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Wyszukujesz frazę "Li, Wei" wg kryterium: Autor


Tytuł:
The Graphs Whose Permanental Polynomials Are Symmetric
Autorzy:
Li, Wei
Powiązania:
https://bibliotekanauki.pl/articles/31342428.pdf
Data publikacji:
2018-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
permanental polynomial
rooted product
matching
Opis:
The permanental polynomial $ \pi (G,x) = \Sigma_{i=0}^n b_i x^{n − i} $ of a graph G is symmetric if $ b_i = b_n−i $ for each $i$. In this paper, we characterize the graphs with symmetric permanental polynomials. Firstly, we introduce the rooted product $ H(K) $ of a graph $ H $ by a graph $ K $, and provide a way to compute the permanental polynomial of the rooted product $ H(K) $. Then we give a sufficient and necessary condition for the symmetric polynomial, and we prove that the permanental polynomial of a graph $ G $ is symmetric if and only if $ G $ is the rooted product of a graph by a path of length one.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 1; 233-243
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Note on the Permanental Roots of Bipartite Graphs
Autorzy:
Zhang, Heping
Liu, Shunyi
Li, Wei
Powiązania:
https://bibliotekanauki.pl/articles/30147218.pdf
Data publikacji:
2014-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
permanent
permanental polynomial
permanental roots
Opis:
It is well-known that any graph has all real eigenvalues and a graph is bipartite if and only if its spectrum is symmetric with respect to the origin. We are interested in finding whether the permanental roots of a bipartite graph G have symmetric property as the spectrum of G. In this note, we show that the permanental roots of bipartite graphs are symmetric with respect to the real and imaginary axes. Furthermore, we prove that any graph has no negative real permanental root, and any graph containing at least one edge has complex permanental roots.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 1; 49-56
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Single-Photon Router in Quantum Fluctuation of Field
Autorzy:
Liu, Li-Wei
Shi, Yu-Qing
Qiong, Chen
Powiązania:
https://bibliotekanauki.pl/articles/1032595.pdf
Data publikacji:
2017-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
single-photon quantum router
Bose-Einstein condensate
cavity optomechanical
Opis:
We investigate a single-photon quantum router in quantum fluctuation of fields. The optomechanical system composed of a cigar-shaped Bose-Einstein condensate trapped in an ultrahigh-finesse Fabry-Pérot cavity. We show how an analog of electromagnetically induced transparency in an optomechanical system can be used to produce a switch for a quantum fluctuation field using very low pumping field strength. The numerical results show that the output photon is completely different by turning the pump off and turning the pump on. We also show that the quantum noise sources are very small. This optomechanical system can serve as a single-photon quantum router.
Źródło:
Acta Physica Polonica A; 2017, 132, 4; 1358-1362
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anti-overturning safety performance investigation for single column pier bridge
Autorzy:
Ji, Yongcheng
Liu, Wenchao
Li, Wei
Wang, Pixiang
Powiązania:
https://bibliotekanauki.pl/articles/2174020.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
podpora jednokolumnowa
most dźwigarowy
stateczność przeciwwywrotna
modelowanie metodą elementów skończonych
przewrócenie
obciążenie krytyczne
obrót
single column pier
girder bridge
anti overturning stability
finite element modelling
overturn
ultimate load
rotation
Opis:
Under eccentric load, a single column pier bridge often overturns. In order to study the anti overturning performance of a single column pier bridge, taking the accident bridge in Wuxi as an example, a finite element model is established based on ABAQUS. According to the model simulation results, the relationship between the ultimate rotational load and overturning load of the accident bridge is obtained, and the ratio of the latter to the former is 1.75. Based on the model, the stress state, displacement state, and support state of the accident bridge under dead load, highway class I vehicle load, and accident vehicle load are obtained. Whether the strength and stability of the accident bridge under each load meet the service requirements is analyzed. In order to explore the differences among China, United States, and Japan specifications, the lateral stability of accident bridges is checked. It is found that the safety of the United States and Japan specifications is conservative, but the utilization rate of bridge traffic capacity is low. The safety of China specifications is slightly lower, but it can maximize the bridge’s traffic capacity and judge the ultimate overturning state of the bridge more accurately. The research results can provide technical references for the design and application of a single-column pier bridge.
Źródło:
Archives of Civil Engineering; 2022, 68, 3; 221--240
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Data correction method of the persistent scatterer interferometric synthetic aperture radar technique in landslide surface monitoring
Autorzy:
Xie, Mo-Ewn
Lv, Fu-Xia
Wang, Li-Wei
Powiązania:
https://bibliotekanauki.pl/articles/89050.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
landslide monitoring
PS-InSAR technology
reservoir landslide
error analysis
Opis:
Landslides generally cause more damage than first predicted. Currently, many methods are available for monitoring landslides occurrence. Conventional methods are mainly based on single-point monitoring, which omits the aspect of variation in large-scale landslides. Due to the development of radar satellites, the differential interferometric synthetic aperture radar technique has been widely used for landslide monitoring. In this study, an experimental region in the Wudongde Hydropower Station reservoir area was studied using archived spaceborne synthetic aperture radar (SAR) data collected over many years. As the permanent scatterer interferometric SAR (PS-InSAR) technique is an advanced technology, it could be suitably used to overcome the time discontinuity in long time series. However, the accuracy of date processing obtained using the PS-InSAR technique is lower than that obtained using the single-point monitoring method. The monitoring results of the PS-InSAR technique only demonstrate the moving trend of landslides and do not present the actual displacement. The Advanced Land Observation Satellite and a high-precision total station were used for long-term landslide monitoring of the Jinpingzi landslide at the Wudongde Hydropower Station reservoir area. Based on a relationship analysis between the data obtained using the PS-InSAR technique and the total station, a revised method was proposed to reduce the errors in the PS-InSAR monitoring results. The method can not only enhance the monitoring precision of the PS-InSAR technology but also achieve long-term monitoring of landslide displacement from a bird's-eye view.
Źródło:
Mining Science; 2019, 26; 91-109
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Band Calculations on the Upper Critical Fields of Iron Pnictide Superconductor $Ba(Fe_{1-x}Ni_x)_2As_2$ (x=0.072)
Autorzy:
Huang, Hai
Lv, Peng-Li
Li, Wei-Feng
Liu, Peng
Powiązania:
https://bibliotekanauki.pl/articles/1399148.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
74.25.Ha
Opis:
Based on two-band Ginzburg-Landau theory, we study the upper critical fields for the overdoped composition of the iron-based superconductor $Ba(Fe_{1-x}Ni_x)_2As_2$ with x=0.072. All the temperature and angular results of this compound are consistent with the experimental data. Thus our analysis strongly suggests that $Ba(Fe_{1-x}Ni_x)_2As_2$ in the overdoped regime is a two-gap superconductor.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 799-802
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Patient-specific finite element analysis of frictional behavior in different esophageal regions during endoscopy
Autorzy:
Lin, Chengxiong
Ren, Pan
Li, Wei
Deng, Hengyi
Zhou, Zhongrong
Powiązania:
https://bibliotekanauki.pl/articles/27324143.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
human esophagus
frictional behavior
finite element model
patient
przełyk człowieka
zachowanie cierne
model elementów skończonych
pacjent
Opis:
Endoscopy is a common and effective method to treat digestive system diseases. Not only can it detect the physiological state of the digestive tract, but also can conduct clinical operations. As a result, it’s of great significance to make clear the relationship between the clinical operation and the complications. Methods: Considering the difficulty in measuring the contact force and determining the stress distribution in real time during endoscopy, a specific-patient finite element model for the frictional behavior at the endoscope-esophagus interface was built in current study. By collecting the CT data of the patient, a 3D esophagus model was built and divided into three characteristic regions (narrow region, thoracic region and abdominal region) according to the physiological structure. Results: Results showed that the radius of the narrowest position was the dominant factor for the maximum von Mises stress when the endoscope passed through the narrow region. For abdominal region and thoracic region, with the increasing coefficient of friction (COF) and amplitude, the total force duo to frictional force (CFSM), frictional dissipation (FD), strain energy (SE) and maximum von Mises stress (Max) all increased correspondingly. Meanwhile, the region of stress concentration gradually approached the initial contact stage. Conclusions: The results can provide theoretical basis and technical support for clinical application and offer some suggestions for medical workers during endoscopy as well.
Źródło:
Acta of Bioengineering and Biomechanics; 2020, 22, 2; 11--24
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the Critical Sizes for Detonation of Cube-shaped Transfer Charges
Autorzy:
Zhao, Xiang-run
Jin, Shi-xin
Huang, Jin-hong
Li, Chao-zhen
Yan, Li-wei
Powiązania:
https://bibliotekanauki.pl/articles/358353.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
explosive train
transfer charge
shock wave sensitivity
minimum safe separation distance
Opis:
In order to obtain the minimum size, thickness and safe separation distance, for the cube-shaped transfer charges used in MEMS (micro-electromechanical system) explosive trains, an explosive train using a JO-9C(III) cube-shaped transfer charge was designed for experimental research. Detonation transfer experiments and detonation interruption experiments were conducted in turn. In initial experiments, the electric detonators were all in the armed position, but different thicknesses of the cube-shaped transfer charges were used. In the later experiments, the thickness of the transfer charges were unchanged, but the separation distances were different. The detonation path of the transfer charge under unsafe conditions was analyzed using the shock wave attenuation law. The results showed that the minimum thickness ranged from 0.2 mm to 0.4 mm, the minimum safe separation distance ranged from 0.4 mm to 0.6 mm; and the cube-shaped transfer charge is detonated by a shock wave from a steel gap rather than air clearance when the safe separation distance is less than the minimum threshold. The thickness design value of the cube-shaped transfer charge (JO-9C(III)) should not be less than 0.6 mm, and the safe separation distance design value of the MEMS explosive train should not be less than 1 mm.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 1; 91-104
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Bidirectional Buck-Boost Converter-Based Switching Ripple Communication Strategy for Intelligent Street Lighting Systems
Autorzy:
Zhang, Yixuan
Hu, Yihua
Tse, Zion
Liu, Yuwei
Deng, Jiamei
Xu, Hui
Wang, Yangang
Li, Wei
Powiązania:
https://bibliotekanauki.pl/articles/1955998.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bidirectional switching ripple communication
buck-boost converter
intelligent street lighting system
pulse width modulation
smart city
Opis:
The light-emitting diode (LED) is an essential component of intelligent street lighting (ISL) systems. An efficient ISL system can not only reduce power consumption by planning LED illuminating time but also reduce maintenance costs through a high degree of automation. In this paper, a buck-boost converter is used to realise composite transmission of power and signals for an ISL system. The power is modulated by the pulse width modulation (PWM) approach, and the switching ripple generated in the PWM process is utilised as the carrier of the signals transmitted between the remote-control centre and the slave nodes. Moreover, the proposed model involves a ‘request to send (RTS)/confirm to send (CTS)’ mechanism to avoid signal conflicts. Compared with the conventional power line communication (PLC) approach, the proposed transmission scheme has the advantages of simple circuit structure and simple system wiring. Additionally, a simulation model built in MATLAB/Simulink proves the designed transmission method has strong anti-noise ability.
Źródło:
Power Electronics and Drives; 2021, 6, 41; 260-275
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Molecular mechanisms of resistance to antifolates, a review
Autorzy:
Banerjee, Debabrata
Ercikan-Abali, Emine
Waltham, Mark
Schnieders, Barbara
Hochhauser, Daniel
Li, Wei
Fan, Jianguo
Gorlick, Richard
Goker, Erdem
Bertino, Joseph
Powiązania:
https://bibliotekanauki.pl/articles/1045204.pdf
Data publikacji:
1995
Wydawca:
Polskie Towarzystwo Biochemiczne
Źródło:
Acta Biochimica Polonica; 1995, 42, 4; 457-464
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on the output characteristics of photovoltaic arrays under partial shading conditions based on peak point approximate calculation method
Autorzy:
Wei, Liming
Li, Kaikai
Powiązania:
https://bibliotekanauki.pl/articles/2086691.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
– characteristic equation
peak point approximate calculation method
peak voltage point
shadow occlusion’s rate
type of illumination distribution
Opis:
The mismatch effect of photovoltaic (PV) arrays due to different illumination intensity has a significant impact on the output characteristics and output power of PV arrays, which is crucial to understand the output characteristics of PV arrays and optimize the array configuration in order to improve the value of the maximum power point. This paper illustrates the short-circuit current mismatch of series circuits, and the open-circuit voltage mismatch of parallel circuits and proposes corresponding solutions for each mismatch phenomenon. The output characteristics of multi-stage series PV arrays and multi-stage parallel PV arrays under complex illumination are analyzed by using the peak point approximation calculation method, and the distribution law of peak voltage points as well as the I-V (Current-Voltage) characteristic equation of each operating section are proposed. On this basis, the output characteristics of 3 x 3 centralized PV arrays are analyzed and verified by simulation. By comparing series and parallel PV arrays with the same condition, as well as several groups of centralized PV arrays with the same topology and different types of illumination distribution, this paper proposes a configuration optimization method for PV arrays. Matlab/Simulink simulation results confirm that the output power of parallel arrays is greater than that of series arrays under the same configuration and illuminationt distribution type, and the peak point is less than that of series arrays under the same configuration and lighting conditions; while in centralized PV arrays, the fewer series modules are shaded, the greater the output power and the less the peak point.
Źródło:
Archives of Electrical Engineering; 2022, 71, 2; 409--424
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Ni60/SiO2 Coating Prepared by the Pyrolysis Products of Rice Husk
Autorzy:
Wei, Chunxue
Li, Hongbing
Powiązania:
https://bibliotekanauki.pl/articles/2203726.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni60/SiO2
coating
rice husk
hardness
wear
Opis:
Surface coating technology, as the main technology to improve the fatigue life of mechanical systems, has been well applied in mechanical equipment. The present study aimed to explore low-cost surface coating preparation technology using inexpensive rice husk as the research object, and the pyrolysis process behavior of rice husk was analyzed. The Ni60/SiO2 coating was prepared on the surface of the 45# steel substrate using the pyrolysis product SiO2 fiber as the reinforcing phase and supersonic plasma-spraying equipment. The results showed no defects such as cracks, pores, and inclusions in the prepared coating. The nanohardness of the Ni60/SiO2 coating reached 6506 μN, and the average friction coefficient reached 0.42. In the friction-and-wear experiment, the Ni60/SiO2 coating was manifested as an abrasive wear mechanism.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 37--42
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-Seas Initiative countries and their competitiveness in Europe
Kraje inicjatywy Trójmorza i ich konkurencyjność w Europie
Autorzy:
Wierzbiński, Bogdan
Surmacz, Tomasz
Wei, Li
Powiązania:
https://bibliotekanauki.pl/articles/548254.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
regional development
regional competitiveness
evolution of economics processes
rozwój regionalny
konkurencyjność regionów
ewolucja procesów ekonomicznych
Opis:
The paper shows the regional characteristics of the Three-Seas area in terms of defining the competitive advantage of the whole region and its countries through the development of relationships and changes in their approaches to the competitive paradigm in this area. The scientific discussion undertaken in this paper is related to internal resources in terms of ICT and human resources development (and its involvement in science and technology – measured by Human Resources for science and technology) as well as innovativeness. The authors have chosen indicators of development that could be beneficial in terms of decreasing historical economic developmental inequalities, with some differences between the Three-Seas countries being analysed for the period of 2006–2018. The secondary data was taken from Eurostat and other available sources. The regional strategy should focus on the knowledge-based economy, and the possibilities for rapid development in this area. This gives opportunities to make rapid progress in a region centrally located in Europe to generate great potential to strengthen accumulated resources and, in the nearest future, to create the possibility of becoming a hub connecting eastern and western Europe.
W pracy przedstawiono regionalną charakterystykę obszaru Trójmorza pod względem określania przewagi konkurencyjnej całego regionu i jego krajów poprzez rozwój relacji i zmianę podejścia do konkurencyjnego paradygmatu tego obszaru. Dyskusja naukowa podjęta w tym artykule odnosi się do zasobów wewnętrznych związanych z rozwojem ICT i potencjału ludzkiego (i jego wpływu na naukę i technologię – mierzoną przez HRSC, czyli Human resources for science and technology), a także z innowacyjnością. Autorzy wybrali wskaźniki rozwoju, które mogą być korzystne pod względem zmniejszania historycznych nierówności rozwojowych pod względem gospodarczym, a różnice między krajami Trójmorza zostały przeanalizowane dla lat 2006–2018. Dane wtórne pochodzą z Eurostatu i innych dostępnych źródeł. Strategia regionalna powinna koncentrować się na gospodarce opartej na wiedzy, dającej możliwości rozwoju tego obszaru. Daje to możliwość szybkiego rozwoju regionu o centralnej lokalizacji w Europie, co stwarza doskonałą okazję do wzmocnienia zakumulowanych zasobów, a w najbliższej przyszłości daje szansę na stanie się łącznikiem między wschodem a zachodem w Europie.
Źródło:
Nierówności Społeczne a Wzrost Gospodarczy; 2020, 62; 75-88
1898-5084
2658-0780
Pojawia się w:
Nierówności Społeczne a Wzrost Gospodarczy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improved linear complexities of the frequency hopping sequences in two optimal sets
Autorzy:
Gao, J.
Li, X.
Wei, Y.
Powiązania:
https://bibliotekanauki.pl/articles/206234.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
frequency hopping sequence
linear complexity
permutation polynominal
optimal set
Opis:
For the anti-jamming purpose, high linear complexity is desired for each frequency hopping sequence in an optimal set. Using a proper power permutation, Wang has shown that an optimal set of frequency hopping sequences with small linear complexity can be transformed into a new optimal set of frequency hopping sequences with large linear complexity. This paper conains two results. First, we extend the result of Wang. A power permutation is only suitable for a special construction of optimal set of frequency hopping sequences, see Wang (2011). However, the power permutation chosen in this paper applies to the general construction of optimal set of frequency hopping sequences. Second, by using a binomial permutation polynomial P(x), which is different from those permutations used before, we obtain a novel optimal set of frequency hopping sequences with high linear complexity from an optimal set of frequency hopping sequences with small linear complexity. By counting the number of different roots in the sequence representation, we determine the linear complexities of the frequency hopping sequences in two optimal sets transformed by the power permutation or binomial permutation.
Źródło:
Control and Cybernetics; 2012, 41, 2; 317-334
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pilling Performance of Cashmere Knitted Fabric of Woollen Ring Yarn and Mule Yarn
Pilling dzianin kaszmirowych wykonanych z wełnianych przędz obrączkowych i wózkowych
Autorzy:
Li, L.
Zhu, M.
Wei, X
Powiązania:
https://bibliotekanauki.pl/articles/231821.pdf
Data publikacji:
2014
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
cashmere knitted fabric
ring yarn
mule yarn
pilling
kaszmirowe dzianiny
przędza ring
przędza muł
mechacenie
Opis:
The yarn for cashmere knitted fabric is mainly processed by ring spinning and mule spinning. In this paper, four kinds of cashmere dye colours (red, black, grey, and beige) were selected to compare the pilling performance of cashmere knitted fabric of mule yarn and ring yarn. The pilling rates of the fabrics for different colours and spinning methods were tested using ICI’s Pilling Box, and the worn-off weight of the pill and fuzz for each sample was measured using an electronic balance. The results showed that the pilling rate of cashmere knitted fabric of mule yarn is higher than that of ring yarn, and that the worn-off weight of cashmere knitted fabric of mule yarn is less than that of ring yarn.
Przędze przeznaczone dla dzianin kaszmirowych są głównie produkowane na przędzarkach obrączkowych i wózkowych. W pracy badano przędze barwione czterema kolorami (czerwony, czarny, szary i beż). Pilling dzianin wykonanych z przędz o czterech kolorach i na dwóch rodzajach przędzarek sprawdzono za pomocą „ICI Pilling Box”, za pomocą ważenia dzianin oraz wytworzonego puchu pil każdej z próbek. Stwierdzono, że pilling dzianin wykonanych z przędz przędzarek wózkowych jest większy niż z przędz obrączkowych.
Źródło:
Fibres & Textiles in Eastern Europe; 2014, 1 (103); 74-75
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On controllability for fractional differential inclusions in Banach spaces
Autorzy:
Wang, J.
Li, X.
Wei, W.
Powiązania:
https://bibliotekanauki.pl/articles/256046.pdf
Data publikacji:
2012
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
controllability
fractional differential inclusions
Bohnenblust-Karlin's fixed point theorem
Opis:
In this paper, we investigate the controllability for systems governed by fractional differential inclusions in Banach spaces. The techniques rely on fractional calculus, multivalue mapping on a bounded set and Bohnenblust-Karlin's fixed point theorem.
Źródło:
Opuscula Mathematica; 2012, 32, 2; 341-356
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Academic and linguistic gains during a semester long study abroad: A cohort case study
Autorzy:
Cai, Wei
Li, Xiangrong
Liu, Meihua
Powiązania:
https://bibliotekanauki.pl/articles/780741.pdf
Data publikacji:
2013-12
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
gain
exchange program
academic
linguistic
Opis:
The present case study investigated university students’ academic and linguistic gains during a semester-long exchange program abroad. Thirty three third-year English majors from a Chinese university answered a battery of questionnaires and 13 of them participated in semi-structured interviews both prior to and after the program. Analyses of the data showed that the participants gained greatly from the exchange program both academically and linguistically. Based on the findings, some implications about exchange programs are discussed.
Źródło:
Studies in Second Language Learning and Teaching; 2013, 3, 4; 505-522
2083-5205
2084-1965
Pojawia się w:
Studies in Second Language Learning and Teaching
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on Airflow Background Noise Suppression for Aeroacoustic Wind Tunnel Testing
Autorzy:
Li, Yuanwen
Li, Min
Feng, Daofang
Yang, Debin
Wei, Long
Powiązania:
https://bibliotekanauki.pl/articles/2141671.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aeroacoustic measurement
acoustic source localization
EEMD; background noise suppression
wind tunnel test.
Opis:
The microphone data collected in aeroacoustic wind tunnel test contains not only desired aeroacoustic signal but also background noise generated by the jet or the valve of the wind tunnel, so the desired aeroacoustic characteristics is difficult to be highlighted due to the low Signal-to-Noise Ratio (SNR). Classical cross spectral matrix removal can only reduce the microphone self-noise, but its effect is limited for jet noise. Therefore, an Airflow Background Noise Suppression method based on the Ensemble Empirical Mode Decomposition (ABNSEEMD) is proposed to eliminate the influence of background noise on aeroacoustic field reconstruction. The new method uses EEMD to adaptively separate the background noise in microphone data, which has good practicability for increasing SNR of aeroacoustic signal. A localization experiment was conducted by using two loudspeakers in wind tunnel with 80 m/s velocity. Results show that proposed method can filter out the background noise more effectively and improve the SNR of the loudspeakers signal compared with spectral subtraction and cepstrum methods. Moreover, the aeroacoustic field produced by a NACA EPPLER 862 STRUT airfoil model was also measured and reconstructed. Delay-and-sum beamforming maps of aeroacoustic source were displayed after the background noise was suppressed, which further demonstrates the proposed method’s advantage.
Źródło:
Archives of Acoustics; 2022, 47, 2; 241-257
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative evaluation of wear behavior of tribo-pairs in reciprocating pumps with multiple materials under different conditions
Autorzy:
Li, Ran
Wei, Wenshu
Liu, Hao
Wang, Dalong
Ye, Jian
Li, Shoubin
Wang, Wei
Wu, Huigang
Powiązania:
https://bibliotekanauki.pl/articles/2200870.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
reciprocating pump
tribo-pair
cast iron pin
wear behavior
wear resistance
Opis:
In the study of wear behavior of tribo-pairs in reciprocating pumps, the tribo-pairs can be considered as contact pairs consisting of a disc and pin. In this paper, pin-on-disc wear tests were carried out by using two types of cast iron pin specimens with different materials. Additionally, the effects of the lubrication condition, test load, diamond-like carbon (DLC) coating and plateau honing cross-hatch pattern on wear behavior of the tribo-pairs were investigated. Experimental results based on surface topography analysis and scanning elec- tron micrograph (SEM) analysis show that the lubricant and DLC coating have a positive effect on wear resistance of test specimens. Disc specimens of three material types (i.e. ISO 185/JL/250, tin-bronze, zirconia) are able to show good anti-wear behavior. The tribo-pairs composed of spheroidal graphite cast irons as well as implementation of the plateau honing cross hatch on disc specimens have no significant effect on the wear resistance. The Archard model was used to estimate abrasive wear under dry conditions, which was over-predicted compared to the experimental results.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 77--87
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Triplex qRT-PCR with specific probe for synchronously detecting Bovine parvovirus, bovine coronavirus, bovine parainfluenza virus and its applications
Autorzy:
Geng, J.
Niu, Y.
Wei, L.
Li, Q.
Gong, Z.
Wei, S.
Powiązania:
https://bibliotekanauki.pl/articles/2087278.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bovine parvovirus
bovine coronavirus
bovine parainfluenza virus
qRT-PCR
specificity
sensitivity
Źródło:
Polish Journal of Veterinary Sciences; 2020, 23, 4
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Utility optimization-based bandwidth allocation for elastic and inelastic services in peer-to-peer networks
Autorzy:
Li, Shiyong
Zhang, Yue
Wang, Yan
Sun, Wei
Powiązania:
https://bibliotekanauki.pl/articles/330690.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
peer-to-peer network
bandwidth allocation
elastic services
inelastic services
utility function
sieć peer-to-peer
alokacja przepustowości
funkcja użyteczności
Opis:
This paper considers reasonable bandwidth allocation for multiclass services in peer-to-peer (P2P) networks, measures the satisfaction of each peer as a customer by a utility function when acquiring one service, and develops an optimization model for bandwidth allocation with the objective of utility maximization. Elastic services with concave utilities are first considered and the exact expression of optimal bandwidth allocation for each peer is deduced. In order to obtain an optimum in distributed P2P networks, we develop a gradient-based bandwidth allocation scheme and illustrate the performance with numerical examples. Then we investigate bandwidth allocation for inelastic services with sigmoidal utilities, which is a nonconvex optimization problem. In order to solve it, we analyze provider capacity provisioning for bandwidth allocation of inelastic services and modify the update rule for prices that service customers should pay. Numerical examples are finally given to illustrate that the improved scheme can also efficiently converge to the global optimum.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2019, 29, 1; 111-123
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nano-sized micelles formed by self-assembling of polylactide(ethylene glycol) block copolymers in aqueous solutions
Autorzy:
Yang, L.
Zhao, Z.
Wei, J.
Li, S.
Powiązania:
https://bibliotekanauki.pl/articles/284952.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Tematy:
kopolimery
copolymers
Źródło:
Engineering of Biomaterials; 2007, 10, no. 63-64; 16-18
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of oat β-glucan on in vitro digestion characteristics of set-type yogurt
Autorzy:
Qu, Xiaoqing
Li, Bo
Yang, Wei
Nazarenko, Yuliya
Powiązania:
https://bibliotekanauki.pl/articles/2142863.pdf
Data publikacji:
2022
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
oat beta-glucan
yogurt
in vitro digestion
antioxidative activity
cholesterol solubility
beta-glukan z owsa
jogurt
trawienie in vitro
aktywność antyoksydacyjna
rozpuszczalność cholesterolu
Opis:
The main objective of the study was to evaluate the effect of added 0.3% (w/w) oat β-glucan (OG) in set-type yogurt on its protein digestion using an in vitro gastrointestinal model. During gastric digestion phase, the amount of soluble proteins and peptides increased to 25% and 40% for control yogurt (yogurt without OG) and 0.3% OG yogurt, respectively. Buccal digestion has little effect on the structure of yogurts, while large spherical vesicles were formed for both control yogurt and 0.3% OG yogurt after gastric digestion. The presence of 0.3% OG promoted the hydrolysis of yogurt in the gastric digestion phase and caused higher antioxidant activity. Compared with that of control yogurt, the inhibition of cholesterol solubility of 0.3% OG yogurt showed no differences after buccal digestion but significantly higher after gastrointestinal digestion (21.3% for gastric and 22.7% for intestinal digestion). Overall, this study enhances the understanding of digestion characteristics of 0.3% OG-fortified set-type yogurt and provides a theoretical basis for the development of this kind of dairy products.
Źródło:
Acta Innovations; 2022, 43; 5-14
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A combinatorial auction mechanism for time-varying multidimensional resource allocation and pricing in fog computing
Autorzy:
Li, Shiyong
Zhang, Yanan
Sun, Wei
Liu, Jia
Powiązania:
https://bibliotekanauki.pl/articles/15548021.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fog computing
combinatorial auction
time varying multidimensional resource allocation
resource pricing
mgła obliczeniowa
aukcja kombinatoryczna
wycena zasobów
Opis:
It is a hot topic to investigate resource allocation in fog computing. However, currently resource allocation in fog computing mostly supports only fixed resources, that is, the resource requirements of users are satisfied with a fixed amount of resources during the usage time, which may result in low utility of resource providers and even cause a waste of resources. Therefore, we establish an integer programming model for the time-varying multidimensional resource allocation problem in fog computing to maximize the utility of the fog resource pool. We also design a heuristic algorithm to approximate the solution of the model. We apply a dominant-resource-based strategy for resource allocation to improve resource utilization as well as critical value theory for resource pricing to enhance the utility of the fog resource pool. We also prove that the algorithm satisfies truthful and individual rationality. Finally, we give some numerical examples to demonstrate the performance of the algorithm. Compared with existing studies, our approach can improve resource utilization and maximize the utility of the fog resource pool.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2023, 33, 2; 327--339
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Generalized Rainbow Connection of Graphs and their Complements
Autorzy:
Li, Xueliang
Magnant, Colton
Wei, Meiqin
Zhu, Xiaoyu
Powiązania:
https://bibliotekanauki.pl/articles/31342420.pdf
Data publikacji:
2018-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
ℓ-rainbow path
( k, ℓ)-rainbow connected
( k, ℓ)-rainbow connection number
Opis:
Let $G$ be an edge-colored connected graph. A path $P$ in $G$ is called $ \mathcal{l} $-rainbow if each subpath of length at most $ \mathcal{l} + 1 $ is rainbow. The graph $G$ is called $(k, \mathcal{l} )$-rainbow connected if there is an edge-coloring such that every pair of distinct vertices of $G$ is connected by $k$ pairwise internally vertex-disjoint $ \mathcal{l} $-rainbow paths in $G$. The minimum number of colors needed to make $G$ $(k, \mathcal{l})$-rainbow connected is called the $ (k, \mathcal{l} )$-rainbow connection number of $G$ and denoted by $ rc_{ k,\mathcal{l} } (G) $. In this paper, we first focus on the (1, 2)-rainbow connection number of $G$ depending on some constraints of $ \overline{G} $. Then, we characterize the graphs of order $n$ with (1, 2)-rainbow connection number $ n − 1 $ or $ n − 2 $. Using this result, we investigate the Nordhaus-Gaddum-Type problem of (1, 2)-rainbow connection number and prove that $ rc_{1,2}(G) + rc_{1,2}( \overlina{G} ) \le n + 2 $ for connected graphs $ G $ and $ \overline{G} $. The equality holds if and only if $G$ or $ \overline{G} $ is isomorphic to a double star.
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 2; 371-384
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A near-infrared fluorescent probe for selective detection of fluorion
Autorzy:
Kang, Yan-Fei
Wei, Fan
Meng, Ya-Li
Xin, Zhen-Hui
Wei, Dong
Powiązania:
https://bibliotekanauki.pl/articles/778367.pdf
Data publikacji:
2020
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Probe
Fluorescence
Fluoride anion
Selectivity
Near-infrared
Opis:
In this work, we have designed and synthesized the fluorescent probe 1, which was capable to selectively detect fluoride anion (F). More importantly, the probe 1 possessed near-infrared excitation and emission wavelengths (excitation at 650 nm and emission at 695), and the probe solution had changed dramatically from yellow to cyan with the addition of F. In addition, the fluorescence intensity exhibited perfectly positive correlation with concentration of F concentration from 0 to 40 μM (R2 = 0.9972), which offered the important condition for quantitative analysis. The probe 1 owned detection limit of 46 nM. Therefore, this near-infrared probe can be of great benefit for detecting F in practical application.
Źródło:
Polish Journal of Chemical Technology; 2020, 22, 1; 1-5
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on path optimization for multimodal transportation of hazardous materials under uncertain demand
Autorzy:
Han, Wei
Chai, Huo
Zhang, Jianpeng
Li, Yuanping
Powiązania:
https://bibliotekanauki.pl/articles/27311810.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
hazardous materials
multimodal transport
routing optimization
fuzzy random numbers
NSGA-II
materiały niebezpieczne
transport multimodalny
optymalizacja tras
Opis:
In the process of long-distance and large-volume transportation of hazardous materials (HAZMAT), multimodal transportation plays a crucial role with its unique advantages. In order to effectively reduce the transportation risk and improve the reliability of transportation, it is particularly important to choose a suitable transportation plan for multimodal transport of HAZMAT. In this paper, we study the transportation of HAZMAT in multimodal transport networks. Considering the fluctuation in demand for HAZMAT during the actual transportation process, it is difficult for decision makers to obtain the accurate demand for HAZMAT orders in advance, leading to uncertainty in the final transportation plan. Therefore, in this paper, the uncertain demand of HAZMAT is set as a triangular fuzzy random number, and a multi-objective mixed integer linear programming model is established with the objective of minimizing the total risk exposure population and the total cost in the transportation process of HAZMAT. In order to facilitate the solution of the model, we combined the fuzzy random expected value method with the fuzzy random chance constraint method based on credibility measures to reconstruct the uncertain model clearly and equivalently, and designed a non-dominated sorting genetic algorithm (NSGA-Ⅱ) to obtain the Pareto boundary of the multi-objective optimization problem. Finally, we conducted a numerical example experiment to verify the rationality of the model proposed in this paper. The experimental results indicate that uncertain demand can affect the path decision-making of multimodal transportation of HAZMAT. In addition, the confidence level of fuzzy random opportunity constraints will have an impact on the risk and economic objectives of optimizing the multimodal transportation path of HAZMAT. When the confidence level is higher than 0.7, it will lead to a significant increase in transportation risks and costs. Through sensitivity analysis, it can provide useful decision-making references for relevant departments to formulate HAZMAT transportation plans.
Źródło:
Archives of Transport; 2023, 67, 3; 91--104
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on the mechanism of the difference in flotation performance between fine-grained crystalline SiO2 and amorphous SiO2
Autorzy:
Ma, Saisai
Li, Jie
Wang, Yonglun
Wei, Bangqi
Powiązania:
https://bibliotekanauki.pl/articles/27323646.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
flotation separation
heteromorphism
infrared spectrum calculation
DLVO theory
Opis:
Numerous minerals found in nature contain silica, including quartz, cristobalite, opal, etc. They have the same chemical composition but different crystal structures, and this phenomenon is called “polymorphism” in mineralogy. For these polymorphic and multi-like minerals, in the flotation process, will it directly or indirectly affect the flotation effect. Based on this, this study mainly explores the difference between crystalline SiO2 and amorphous SiO2 in flotation. In this study, two crystal forms of SiO2 were subjected to flotation and adsorption capacity tests. FTIR, other test techniques, the chemical calculation of the flotation solution, and the theoretical calculation of the DLVO can all be used to provide an explanation. Finally, in the flotation experiment, the feedbacks of the two minerals to the change of the pH value of the pulp and the change of the concentration of the reagent are different. Through the comprehensive analysis of the adsorption capacity test and semi-quantitative calculation of the infrared spectrum, the adsorption capacity of crystalline SiO2 to drugs is about 23% higher than amorphous SiO2. Furthermore, during the flotation process, the amorphous SiO2 particles will agglomerate together and entrain into the foam through, resulting in concentrate pollution. So amorphous SiO2 will undoubtedly increase the difficulty of flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 6; art. no. 174567
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
Autorzy:
Ju, Yang
Wei, Zhengxian
Li, Huangfu
Feng, Xiao
Powiązania:
https://bibliotekanauki.pl/articles/259300.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
acoustic
low SNR
signal classification
feature maintain
dimension reduction
Opis:
The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
Źródło:
Polish Maritime Research; 2020, 2; 187-198
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear drift of the spring gravimeter caused by air pressure from the kunming GS15 gravimeters
Autorzy:
Wei, J.
Shen, W.
Li, H.
Liu, Z.
Powiązania:
https://bibliotekanauki.pl/articles/260586.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
GS15 gravimeter meter
air pressure admittance
nonlinear air pressure correction
superconducting gravimeter
Opis:
In order to monitor and correct the meteorological factors of the spring gravity meter, the characteristics of the time varying gravity changes caused by meteorological factors were analyzed. Kunming GS15 gravity meter from 2007 continuous gravity observation has been carried out with the sampling rate of the pressure observation. In this study, we first compare the effects of 4 types of gravity meter and 3 different types of stations on the gravity observed seasonal gravity signals. It is indicated that the observed seasonal gravity signal of the cave is only 1/10, and there is a constant temperature and constant pressure device. Compared with the same time, the gravity signal of the gravity signal is about 100 times smaller. The influence of the pressure load of the gravity meter is tested by using the theory of pressure. The results show that only the actual value of 2cpd - 3cpd pressure load varies from -0.395 to -0.280×10-8ms-2 , and the 1cpd to 1 cpm periodic partial type gravity meter is also in accordance with the law of gravity and air pressure. And with the characteristics of time lag. In this paper, the nonlinear zero drift parameters of the linear regression model with time lag and the time series of the GS15 gravity meter are used to simulate the nonlinear zero drift parameters of the gravity meter. The results show that the gravity signal contains time lag 35 hours, and the air pressure admittance is 0.8 × 10-8ms-2/mbar. The correlation can reach 79%. The gravity changes signal and satellite gravity as well as the gravity water load signal of the land water model are the same as the gravity water load signal in the autumn as the minimum value, and the seasonal variation of the maximum value of gravity in summer.
Źródło:
Polish Maritime Research; 2016, S 1; 180-186
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accurate identification on individual similar communication emitters by using HVG-NTE feature
Autorzy:
Li, Ke
Ge, Wei
Yang, Xiaoya
Xu, Zhengrong
Powiązania:
https://bibliotekanauki.pl/articles/2128146.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
communication emitter
identification
feature extraction
HVG
NTE
emiter komunikacji
identyfikacja
wyodrębnianie cech
Opis:
Individual identification of similar communication emitters in the complex electromagnetic environment has great research value and significance in both military and civilian fields. In this paper, a feature extraction method called HVG-NTE is proposed based on the idea of system nonlinearity. The shape of the degree distribution, based on the extraction of HVG degree distribution, is quantified with NTE to improve the anti-noise performance. Then XGBoost is used to build a classifier for communication emitter identification. Our method achieves better recognition performance than the state-of-the-art technology of the transient signal data set of radio stations with the same plant, batch, and model, and is suitable for a small sample size.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; e136741, 1--6
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Accurate identification on individual similar communication emitters by using HVG-NTE feature
Autorzy:
Li, Ke
Ge, Wei
Yang, Xiaoya
Xu, Zhengrong
Powiązania:
https://bibliotekanauki.pl/articles/2173613.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
communication emitter
identification
feature extraction
HVG
NTE
emiter komunikacji
identyfikacja
wyodrębnianie cech
Opis:
Individual identification of similar communication emitters in the complex electromagnetic environment has great research value and significance in both military and civilian fields. In this paper, a feature extraction method called HVG-NTE is proposed based on the idea of system nonlinearity. The shape of the degree distribution, based on the extraction of HVG degree distribution, is quantified with NTE to improve the anti-noise performance. Then XGBoost is used to build a classifier for communication emitter identification. Our method achieves better recognition performance than the state-of-the-art technology of the transient signal data set of radio stations with the same plant, batch, and model, and is suitable for a small sample size.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 2; art. no. e136741
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of sound on standing postural stability in the elderly with and without knee osteoarthritis
Autorzy:
Hengsomboon, Pichaya
Hiengkaew, Vimonwan
Hsu, Wei-Li
Bovonsunthonchai, Sunee
Powiązania:
https://bibliotekanauki.pl/articles/306232.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
starzenie się
choroba zwyrodnieniowa
staw kolanowy
ageing
auditory
balance
knee osteoarthritis
sensory reweighting
Opis:
The aim of the study was to investigate the influence of sound on standing postural control in the elderly with and without knee osteoarthritis (knee-OA). Methods: Twenty-six elderly with knee-OA and 26 elderly without knee-OA who matched the age and height participated in this study. The standing postural stability was assessed by the 3D motion analysis system. Four testing conditions of the combination of sound (no sound and white noise sound) and surface (firm and soft surfaces) were tested three times with eyes closed for 30 sec. Postural stability variables included the standard deviation and velocity of the centre of pressure, the total body centre of mass, and centre of the head along the antero-posterior (AP) and medio-lateral (ML) directions. Results: Statistical significant reductions of all variables along ML direction were found in the elderly without a knee-OA in the presence of sound during standing on a firm surface. No significant effect of sound was found in the elderly with the knee-OA during standing on a firm surface. In the standing on a soft surface, both groups demonstrated no significant effect of sound on all postural stability variables. Conclusions: Application of sound improved the standing postural stability in the frontal plane for the elderly without knee-OA. However, the effect of sound was limited in standing on a soft surface for both elderly with and without knee-OA.
Źródło:
Acta of Bioengineering and Biomechanics; 2019, 21, 3; 99-108
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Welding Heat Input on Microstructure and Corrosion Characterization in CGHAZ of X80 Pipeline Steel
Autorzy:
Wang, Xue-Mei
Zhao, Wei
Chen, Kai
Li, Zhen
Powiązania:
https://bibliotekanauki.pl/articles/28099607.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
X80 pipeline steel
coarse grain heat-affected zone
heat input
corrosion
Opis:
The coarse-grained heat-affected zone specimens of X80 pipeline steel were produced by welding thermal simulation under different heat inputs of 10, 30, and 55 kJ/cm to study the effects of heat input on microstructure evolution and corrosion characterization. The corrosion resistance of coarse-grained heat-affected zones was poorer than that of base metal due to less homogenous in the former. For 10 kJ/cm coarse-grained heat-affected zone, the corrosion resistance was poorer than the others due to the more adsorption hydrogen around the needle-like martensite/austenite constituents and greater galvanic driving force between the needle-like martensite/austenite constituents and ferrite. In carbonate/bicarbonate solution, better corrosion resistance for coarse-grained heat-affected zones was obtained when the heat input is 30 kJ/cm, which can be attributed to the severe coarse martensite/austenite constituents for 55 kJ/cm coarse-grained heat-affected zone. In the H2S environment, the better corrosion resistance for coarse-grained heat-affected zone was obtained when the heat input is 55 kJ/cm, which can be attributed to the protective effect of corrosion products. In addition, the high content of M/A constituents for 30 kJ/cm CGHAZ was good for hydrogen adsorption, which was adverse to the corrosion resistance in acid environments.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 2; 659--671
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of pH value on effectiveness of biopolymer-based treatment of bauxite mine slurry
Autorzy:
Meng, Jian Ping
Li, Shanmei
Yan, Rongtao
Wei, Changfu
Powiązania:
https://bibliotekanauki.pl/articles/24085778.pdf
Data publikacji:
2023
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pH
biopolymer
xanthan gum
bauxite mine slurry
flocculation
Opis:
Effective dehydration and flocculation of mine slurries or sludge is important for nonferrous metal industries and environmental engineering. However, the mechanisms for the flocculation of slurry remain largely unclear. This paper presents the results of a series of flocculation tests, which was conducted on the slurry suspensions treated by xanthan gum (flocculant) at different pH values. It is shown that the settlement rate of mine slurry particles can be accelerated by adding xanthan gum, and the maximum sedimentation rate was obtained at a pH value of 5.9, and the final volume of flocs is significantly increased due to the addition of the flocculant. In addition, the settlement rates of xanthan gum-treated slurry suspensions at the pH values of 3, 5 and 7 decrease slightly compared with the reference slurry suspensions with pH=5.9, and the slurries remained stable as suspensions at the pH value of 9 and 11. The zeta potential measurement and SEM image analysis show that flocculation occurs primarily due to electrostatic attraction between slurry particles and the flocculants, and the bridging effect between the carboxylic groups in the side chains of xanthan gum molecule and the suspension particles.
Źródło:
Physicochemical Problems of Mineral Processing; 2023, 59, 3; art. no. 167949
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the Correlation between the Structure and Quality of Compact Blend Yarns
Ocena korelacji pomiędzy strukturą i jakością mieszankowych przędz kompaktowych przędzionych dwoma różnymi przędzarkami obrączkowymi
Autorzy:
Li, W.
Su, X.
Zhang, Y.
Xie, C.
Wei, Q.
Powiązania:
https://bibliotekanauki.pl/articles/233941.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
pneumatic compact spinning
blend yarn
hamilton index method
high speed camera
pneumatyczne przędzarki kompaktowe
mieszankowe przędze
Metoda indeksu Hamiltona
szybkobieżna kamera cyfrowa
Opis:
Pneumatic compact spinning is the most widely used compact spinning technology at present, which is implemented by using negative airflow to condense the fibre bundle and decrease the spinning triangle. Roller-type and Lattice apron-type compact spinning are two major kinds of pneumatic compact spinning now. In this paper, blend yarn qualities spun by one kind of roller-type compact spinning: complete condensing spinning (CCS), and one kind of Lattice apron-type compact spinning: 4-line rollers compact spinning (FRCS) were studied and analysed comparatively. First, 28.1, 18.5 and 12.3 tex JC60/T40 blend yarns and 18.5, 14.8 and 11.8 tex JC35/T65 blend yarns were spun on two kinds of compact spinning systems, respectively, and the effects of the blending ratio on yarn qualities were discussed. Then another two kinds of cotton blended yarns - JC60/R40 and JC60/M40 were spun. 28.1, 18.5, 14.8 tex JC60/R40 and 18.5, 14.8, 11.8 tex JC60/M40 were spun on two kinds of compact spinning systems, respectively. Meanwhile the qualities of spun yarns were analysed by using two methods. First with a high speed camera system - OLYMPUS i-speed3 (OLYMPUS Image Co., Ltd., Japan), the condensing process of a fibre strand in the condensing zones were captured and analysed. Second the cross sections of the spun yarns were presented using a Y172 Hardy’s thin cross-section sampling device (Nantong Hongda Experiment Instruments Co., Ltd., China). The corresponding Hamilton Index was then calculated, and the fibre radial distributions in the yarn cross section were analysed. The results show that the fibre condensing effects are increased with an increase in the ratio of cotton fibre on the blended yarn for both kinds of compact spinning, especially the FRCS. Meanwhile with an increase in the ratio of polyester fibre on the blended yarn, the advantage of CCS with respect to yarn qualities increased. For both JC60/R40 and JC60/M40, cotton fibres are transferred to the outer part of the yarn body. However, the fibres in JC60/R40 yarn spun by CCS and those in JC60/M40 yarn spun by FRCS are distributed more randomly.
Przędzenie kompaktowe realizowane na zmodyfikowanych przędzarkach obrączkowych jest obecnie najbardziej rozpowszechnioną techniką przędzalniczą, która została wprowadzona na skalę przemysłową dzięki wykorzystaniu podciśnienia mającego na celu zagęszczenie przetwarzanego w przędzę strumienia włókien oraz zmniejszenie trójkąta przędzenia. Celem prezentowanych przez autorów badań była ocena porównawcza jakości i struktury przędz kompaktowych wytworzonych dwoma systemami kompaktowania. Przedstawiono wyniki badań jakości przędz obrączkowych kompaktowych mieszankowych. Przędze te wyprzędziono z mieszanek bawełny z włóknami poliestrowymi o udziale 65/35, mieszanek bawełny z jedwabiem celulozowym o udziale 60/40 oraz mieszanek bawełny z modalnymi włóknami wiskozowymi o udziale 60/40. Wytworzone przędze analizowano dwoma różnymi metodami. Pierwsza metoda polegała na rejestrowaniu za pośrednictwem szybkobieżnej kamery cyfrowej procesu zagęszczania tasiemki włókien w strefie jej zagęszczania, a następnie analizowaniu struktury tworzącej się przędzy. W drugiej metodzie sporządzano, przy pomocy stanowiska pomiarowego wyposażonego w urządzenie przeznaczone do pobierania próbek oraz mikroskopu, obrazy przekrojów poprzecznych wytworzonych przędz, a także obliczano odpowiednio wskaźniki migracji włókien w przekroju poprzecznym przędzy reprezentowane przez indeksy Hamiltona.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 6 (114); 55-67
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of Acoustic Tubes Array and Application to Measuring Acoustic Loads in Supersonic Airflow
Autorzy:
Wei, L.
Li, M.
Fu, Q.
Fan, Y.
Yang, D.
Powiązania:
https://bibliotekanauki.pl/articles/176750.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic load
acoustic tubes array
near field measurement
supersonic airflow
Opis:
In the acoustic fatigue experiment for hypersonic vehicle in simulated harsh service environment on ground, acoustic loads on the surface of test pieces of the vehicle need to be measured. However, for the normal microphones without high temperature resistance ability, the near field sound measurement cannot be achieved. In this work, on the basis of previous researches, an acoustic tubes array is designed to achieve the near field measurement of acoustic loads on the surface of the test piece in the supersonic airflow with high temperature achieved by coherent jet oxygen lance. Firstly, the process of designing this acoustic tubes array is introduced. Secondly, the equality of phase differences at the front and at the end of the tubes is stated and proved using a phase differences test with an acoustic tubes array whose design is presented in this text; therefore, the phase differences of signals acquired by microphones can be directly applied to beamforming algorithm to determine the acoustic load source. Finally, using above mentioned acoustic tubes array, measurement of acoustic load, with and without a test piece in the supersonic airflow made by the coherent jet oxygen lance, is conducted respectively, and the measurements results are analyzed.
Źródło:
Archives of Acoustics; 2014, 39, 3; 395-402
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A novel Δ12-fatty acid desaturase gene from methylotrophic yeast Pichia pastoris GS115
Autorzy:
Wei, D
Li, M
Zhang, X
Zhou, H
Xing, L
Powiązania:
https://bibliotekanauki.pl/articles/1041169.pdf
Data publikacji:
2006
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
fatty acid desaturase gene
Pichia pastoris
Saccharomyces cerevisiae
linoleic acid
Opis:
The methylotrophic yeast Pichia pastoris GS115, a widely used strain in production of various heterologous proteins, especially membrane-bound enzymes, can also produce linoleic and linolenic acids, which indicates the existence of membrane-bound Δ12 and Δ15-fatty acid desaturases. This paper describes the cloning and functional characterization of a novel Δ12-fatty acid desaturase gene from this methylotrophic yeast. The open reading frame of the gene (named Pp-FAD12) is 1263 bp in size and encodes a 420-amino-acid peptide. The deduced Pp-FAD12 protein shows high identity (50-67%) with Δ12-fatty acid desaturases from other fungi. It also shows a high identity (57%) with Δ15-fatty acid desaturase (named Sk-FAD15) from Saccharomyces kluyveri. Expression of Pp-FAD12 in polyunsaturated fatty acids non-producing yeast Saccharomyces cerevisiae demonstrated that its product converted oleic acid (18 : 1) to linoleic acid (18 : 2). This result suggests that Pp-FAD12 encodes a novel Δ12-fatty acid desaturase in P. pastoris GS115. This is the first report about the cloning and functional characterization of Δ12-fatty acid desaturase gene in methylotrophic yeast.
Źródło:
Acta Biochimica Polonica; 2006, 53, 4; 753-759
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coal permeability change caused by mining-induced stress
Autorzy:
Zhang, Lulu
Li, Bo
Wei, Jianping
Wen, Zhihui
Ren, Yongjie
Powiązania:
https://bibliotekanauki.pl/articles/89077.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
mining-induced stress
permeability
unloading path
sensitivity index
effective stress
Opis:
To study coal permeability evolution under the influence of mining actions, we conducted a sensitivity index test on permeability to determine the influence of axial and confining stresses on coal permeability. Loading and unloading tests were performed afterward, and the differences between loading and unloading paths in terms of strain and permeability were studied. A permeability evolution model was built in consideration of absorption swelling and effective stress during modeling. An effective stress calculation model was also built using axial and confining stresses. The calculation results of the two models were compared with experimental data. Results showed that permeability were more sensitive to confining stress than axial stress, and effective stress placed a large weight on confining stress. Large axial and radial deformations at peak strength were observed during unloading. In the unloading phase, the permeability of coal began to increase, and the increment was enhanced by large initial axial stress when confining stress was loaded. permeability sensitivity to axial and confining stresses were used to explain these permeability changes. The calculation results of the models fitted the experimental data well. Therefore, the proposed models can be used to calculate effective stress on the basis of axial and confining stresses and describe permeability change in coal under the influence of mining actions.
Źródło:
Mining Science; 2019, 26; 203-222
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal and mechanical properties of poly(L-lactic acid) nucleated with N,N’-bis(phenyl) 1,4-naphthalenedicarboxylic acid dihydrazide
Właściwości termiczne i mechaniczne poli(kwasu L-mlekowego) zarodkowanego dihydrazydem kwasu N,N’-bis(fenylo) 1,4-naftalenodikarboksylowego
Autorzy:
Zhao, Li-Sha
Qiao, Jun
Chen, Wei
Cai, Yan-Hua
Powiązania:
https://bibliotekanauki.pl/articles/1789985.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
poly(L-lactic acid)
phenyl hydrazine
nucleation effect
non-isothermal crystallization
mechanical properties
poli(kwas L-mlekowy)
fenylohydrazyna
efekt zarodkowania
krystalizacja nieizotermiczna
właściwości mechaniczne
Opis:
The modified poly(L-lactic acid) (PLLA) with different contents (0.5−3 wt %) of N,N’-bis(phenyl) 1,4-naphthalenedicarboxylic acid dihydrazide (NAPH) were prepared to evaluate effects of NAPH on melt-crystallization behavior (DSC), thermal degradation (TGA) and mechanical properties of PLLA. The melt-crystallization results demonstrated that NAPH as a heterogeneous organic nucleating agent enhanced crystallization ability of PLLA in cooling, and PLLA/1%NAPH had the best crystallization ability because of the highest onset crystallization temperature and the sharpest melt-crystallization peak. However, melt-crystallization behavior also depended on the cooling rate and final melting temperature, overall, a relative slow cooling rate and low final melting temperature were beneficial for crystallization of PLLA. The cold-crystallization results indicated that NAPH had an inhibition for cold-crystallization process of PLLA, and the cold-crystallization peak shifted towards lower temperature and became wider with an increase of NAPH concentration. The different melting behaviors of PLLA/NAPH after melt-crystallization and isothermal-crystallization efficiently reflected the accelerating role of NAPH for PLLA crystallization; the double melting peaks formed in heating were thought to result from melting-recrystallization, as well as that a higher crystallization temperature could cause melting peak to appear in higher temperature regions and possess larger melting enthalpy. A comparative analysis on thermal degradation in air illustrated that the addition of NAPH accelerated decomposition of PLLA, but a decrease of onset decomposition temperature was inhibited by the probable interaction of PLLA with NAPH. Moreover, the tensile test showed that NAPH decreased tensile modulus and elongation at break of PLLA, whereas PLLA with low concentration of NAPH had higher tensile strength than pure PLLA.
Poli(kwas L-mlekowy) (PLLA) modyfikowano dodatkiem 0,5−3 % mas. dihydrazydu kwasu N,N’-bis(fenylo) 1,4-naftalenodikarboksylowego (NAPH). Zbadano wpływ NAPH na topnienie i krystalizację (DSC), degradację termiczną (TGA) i właściwości mechaniczne PLLA. Analiza procesu krystalizacji ze stanu stopionego modyfikowanego PLLA wykazała, że NAPH, jako heterogeniczny organiczny środek zarodkujący, zwiększał zdolność do krystalizacji PLLA podczas chłodzenia, a próbka PLLA/1% NAPH charakteryzowała się najwyższą temperaturą początku krystalizacji i najostrzejszym pikiem krystalizacji ze stanu stopionego. Przebieg procesu krystalizacji zależał również od szybkości chłodzenia i końcowej temperatury topnienia próbki. Względnie mała szybkość chłodzenia i niska końcowa temperatura topnienia były korzystne dla procesu krystalizacji PLLA. Analiza procesu zimnej krystalizacji wskazała, że obecność NAPH hamowała zimną krystalizację PLLA, jej pik przesuwała w kierunku niższych wartości temperatury, a wraz ze wzrostem stężenia NAPH pik stawał się szerszy. Różny przebieg procesów topnienia PLLA/NAPH po krystalizacji ze stanu stopionego i krystalizacji izotermicznej odzwierciedla przyspieszającą rolę NAPH w krystalizacji PLLA. Autorzy uważają, że podwójne piki topnienia powstające podczas ogrzewania wynikają z zachodzącego procesu topnienia-rekrystalizacji, a także, że wyższa temperatura krystalizacji może być przyczyną pojawienia się piku topnienia w obszarach wyższej temperatury i zwiększenia entalpii topnienia. Analiza porównawcza rozkładu termicznego w atmosferze powietrza wykazała, że dodatek NAPH przyspieszył rozkład PLLA, ale prawdopodobne oddziaływanie PLLA z NAPH wpłynęło na zmniejszenie temperatury początku rozkładu. Ponadto, dodatek większej ilości NAPH spowodował zmniejszenie modułu sprężystości przy rozciąganiu i wydłużenia przy zerwaniu PLLA, jednak PLLA zawierający niewielką ilość NAPH wykazywał większą wytrzymałość na rozciąganie niż niemodyfikowany PLLA.
Źródło:
Polimery; 2021, 66, 4; 234--244
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on torque ripple suppression of brushless DC motor based on PWM modulation
Autorzy:
Daode, Zhang
Wei, Lingkang
Hu, Xinyu
Zhang, Chupeng
Li, Xuesheng
Powiązania:
https://bibliotekanauki.pl/articles/141390.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
DC brushless motor
electric propulsion
fuzzy PID control
torque ripple
PWM_ON_PWM modulation
Opis:
Brushless DC motors are often used as the power sources for modern ship electric propulsion systems. Due to the electromagnetic torque ripple of the motor, the traditional control method reduces the drive performance of the motor under load changes. Aiming at the problem of the torque ripple of the DC brushless motor during a noncommutation period, this paper analysis the reasons for the torque ripple caused by pulsewidth modulation (PWM), and proposes a PWM_ON_PWM method to suppress the torque ripple of the DC brushless motor. Based on the mathematical model of a DC brushless motor, this method adopts a double closed-loop control method based on fuzzy control to suppress the torque ripple of the DC brushless motor. The fuzzy control technology is integrated into the parameter tuning process of the proportional–integral–derivative (PID) controller to effectively improve the stability of the motor control system. Under the Matlab/Simulink platform, the response performance of different PID control methods and the torque characteristics of different PWM modulation methods are simulated and compared. The results show that the fuzzy adaptive PID control method has good dynamic response performance. It is verified that the PWM_ON_PWM modulation method can effectively suppress the torque ripple of the motor during non-commutation period, improve the stability of the double closed-loop control system and meet the driving performance of the motor under different load conditions.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 843-858
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rare Earth Elements supply vs. clean energy technologies: new problems to be solve
Dostawy pierwiastków ziem rzadkich (REE) a czyste technologie energetyczne: nowe problemy do rozwiązania
Autorzy:
Zhou, B.
Li, Z.
Zhao, Y.
Zhang, C.
Wei, Y.
Powiązania:
https://bibliotekanauki.pl/articles/216173.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
Tematy:
rare earth element
clean energy technology
supply chain
pierwiastki ziem rzadkich
czysta technologia energetyczna
łańcuch dostaw
Opis:
Rare earth elements (REEs) provide important properties to clean energy technologies such as wind turbine and hybrid electric vehicles. The global REE demand will grow rapidly during the global transformation toward a greener economy in the next decades. This high demand will require a steady supply chain in the long run. China has a monopoly of global REE production and extraction. The global REE supply chain runs the risk of disruption along with Chinese REE policy evolution. To overcome this supply chain vulnerability, new strategies and measures should be adopted to satisfy future REE supply/demand. There is a pressing need to explore REE deposits, develop efficient REE recycling techniques from end-of-life products, improve substitution technologies for REEs, and reduce the number of critical REEs used in devices. Such measures are facing significant challenges due to environmental factors and an unbalanced market, and overcoming them requires efforts from government and REE companies.
Pierwiastki ziem rzadkich (Rare Earths Elements) mają istotne znaczenie dla rozwoju czystych technologii energetycznych, takich jak turbiny wiatrowe czy pojazdy hybrydowe. Światowy popyt na REE będzie wzrastał w związku z globalną transformacją w kierunku bardziej czystej (ekologicznej) gospodarki w okresie najbliższych dziesięcioleci. Wysoki popyt wymagać będzie stabilnego łańcucha dostaw REE w dłuższej perspektywie. Chiny mają monopol w zakresie globalnej produkcji i wydobycia REE. Światowe dostawy REE obarczone są jednak ryzykiem zakłóceń wynikających z chińskiej polityki w tym zakresie. W związku z tym, powinny być przyjęte nowe środki i strategie w celu zaspokojenia przyszłego popytu/podaży na REE. Istnieje pilna konieczność: poszukiwania nowych złóż, opracowania skutecznych technik recyklingu z wycofanych z eksploatacji produktów, poprawy technologii z zastosowaniem substytutów REE oraz zmniejszenie liczby krytycznych pierwiastków ziem rzadkich w stosowanych urządzeniach. Działania te stanowią poważne wyzwanie ze względu na czynniki środowiskowe i niezrównoważony rynek (monopol podaży). Przezwyciężenie ich wymaga odpowiednich działań ze strony rządu i firm zajmujących się produkcją REE.
Źródło:
Gospodarka Surowcami Mineralnymi; 2016, 32, 4; 29-44
0860-0953
Pojawia się w:
Gospodarka Surowcami Mineralnymi
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Helicobacter pylori cytotoxin-associated gene A impairs the filtration barrier function of podocytes via p38 MAPK signaling pathway
Autorzy:
Yang, Man
Wang, Ling
Gu, Li-jie
Yuan, Wei-jie
Powiązania:
https://bibliotekanauki.pl/articles/1038590.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
CagA
ZO-1
p38 MAPK
podocyte
proteinuria
Opis:
Helicobacter pylori (Hp) specific antigens were found deposited in the glomeruli in some kidney diseases. However, the underlying molecular mechanisms remain to be elucidated. The aim of this study was to investigate the effect of cytotoxin associated gene A protein (CagA), a key virulence factor of Hp, on mouse podocytes. Cells were cultured and treated with recombinant CagA protein. The expression of the tight junction protein ZO-1 and p38 MAPK signaling pathway activation were measured with real-time RT-PCR and western blotting. The filtration barrier function of podocytes was evaluated with albumin influx assay. CagA decreased the expression and membrane distribution of ZO-1, impaired the filtration barrier function of podocytes, while activating p38 MAPK signaling pathway in these cells. Selective p38 MAPK inhibition partly prevented CagA-induced filtration barrier dysfunction of podocytes through ameliorating ZO-1 downregulation. Taken together, the results suggested that CagA, at least via p38 MAPK signaling pathway, may induce podocyte injury. Anti-Hp therapy may be beneficial for the treatment of kidney diseases related to Hp antigen deposition.
Źródło:
Acta Biochimica Polonica; 2017, 64, 3; 471-475
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shrink-Proof Treatment Parameter Optimisation of Cashmere Yarn
Autorzy:
Li, Long
Wang, Wei
Zhang, Xian
Wu, Lei
Yang, Dan
Powiązania:
https://bibliotekanauki.pl/articles/2171991.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
cashmere yarn
shrink-proof
potassium permanganate treatment
yarn shrinkage percentage
Opis:
Cashmere fiber has soft hand and good elasticity. However, it exhibits shrink because of its scale. In this work, cashmere yarn (38.26 tex) was treated using NaCl-KMnO4 to reduce the shrink of cashmere yarn. Orthogonal design and fuzzy comprehensive evaluation were used for optimizing treating parameters. Experimental results showed that the yarn shrink percentage of treated yarn was 0.56% which was less than that untreated yarn, and the treated yarn strength had a little drop compared with untreated yarn. The fiber scale outline of treated yarn could be observed by SEM, but the scale edge is blunt and irregular.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 3 (151); 57--60
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A unified calculation of the optical and EPR spectral data for the trigonal Cr³⁺ center in Cr³⁺-doped α-RbAl(SO₄)₂·12H₂O alum crystal
Autorzy:
Li, Xiao-Wu
Mei, Yang
Wei, Cheng-Fu
Zheng, Wen-Chen
Powiązania:
https://bibliotekanauki.pl/articles/1070555.pdf
Data publikacji:
2016-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.70.Ch
76.30.Fc
78.40.Ha
78.55.Hx
Opis:
The optical band positions and the spin-Hamiltonian parameters (g factors g_{∥}, g_{⊥}, and zero-field splitting parameter D) of alum α-RbAl(SO₄)₂·12H₂O:Cr³⁺ are calculated by diagonalizing the 120× 120 complete energy matrix based on the two-spin-orbit-coupling-parameter model. The model takes into account not only the contributions due to the spin-orbit-coupling parameter of central d^{n} ion in the conventional crystal field theory, but also those due to ligands via covalence effect. The calculation indicates that the fourteen observed spectral data (eleven optical band positions and three spin-Hamiltonian parameters) can be reasonably and uniformly explained with four adjustable parameters (the Racah parameters B, C, intrinsic parameter A̅₄(R) in the superposition model, and the trigonal distortion angle β). The calculations also suggest that contrary to the previous findings, the trigonal distortion of Cr³⁺ (entering the Al³⁺ site in the host crystal) center in α-RbAl(SO₄)₂·12H₂O is induced mainly by the oxygen (or water) octahedron around the Cr³⁺ ion rather than the more distant neighbors.
Źródło:
Acta Physica Polonica A; 2016, 129, 3; 340-343
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stigmasterol blocks cartilage degradation in rabbit model of osteoarthritis
Autorzy:
Chen, Wei-Ping
Yu, Chong
Hu, Peng-Fei
Bao, Jia-Peng
Tang, Jing-Li
Wu, Li-Dong
Powiązania:
https://bibliotekanauki.pl/articles/1039645.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
matrix metalloproteinases
stigmasterol
osteoarthritis
Opis:
Stigmasterol has been shown exihbit anti-osteoarthritic properties in vitro studies. However, the in vivo effects of stigmasterol on cartilage are still unclear. This study investigated the anti-osteoarthritic properties of stigmasterol on cartilage degradation in a rabbit model of osteoarthritis (OA). Twenty rabbits underwent bilateral anterior cruciate ligament transection (ACLT) to induce OA. Five rabbits were used as normal control. Two weeks after operation, the rabbits were randomly divided into two groups. Each group of 10 rabbits received intra-articular injection with 0.3 ml of stigmasterol in left knees and vehicle in right knees, once weekly. Group 1 was killed 6 weeks after ACLT and 2 were sacrificed 9 weeks after ACLT. The knee joints were assessed by gross morphology, histology and gene expression analysis. We found that expression of genes encoding matrix metalloproteinases (MMPs) was significantly higher while tissue inhibitors of metalloproteinase (TIMP)-1 was significantly lower in the both joints of the two OA groups compared to normal contrals. Stigmasterol reduced the cartilage degradation as assessed by histological analysis and markedly suppressed MMPs expression both in group 1 and group 2. Our results suggest that stigmasterol may be considered as a possible therapeutical agent in the treatment of OA.
Źródło:
Acta Biochimica Polonica; 2012, 59, 4; 537-541
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation and characterization of high count yak wool yarns spun by complete compacting spinning and fabrics knitted from them
Przygotowanie i charakterystyka przędz o dużej masie liniowej z wełny jaków przędzionych systemem kompaktowym rotorowym oraz dzianiny wykonane z tych przędz
Autorzy:
Li, W.
Liu, X.
Liu, C.
Su, X.
Xie, C.
Wei, Q.
Powiązania:
https://bibliotekanauki.pl/articles/232629.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
yak wool
pure high count yarns
complete compacting spinning
CCS
yarn quality
knitted wearability
przędza z jaka
przędzenie kompaktowe
przędzenie obrączkowe
jakość przędzy
Opis:
The attentions of the textile industry has been attracted by yak wool due to its excellent properties, environmental friendly characteristics and inexpensive prices. However, the processing of yak wool is difficult due to the larger fiber dispersion and stiffness, especially spun pure and high count yak wool yarn. Therefore, in this paper, a kind of roller-type compact spinning - complete compacting spinning (CCS) was applied to spun pure high count yak wool yarns, in which a special hollow roller made of stainless steel with a strip groove structure on its surface was employed. Based on the mechanism of CCS, the processing parameters for two kinds of yak wool yarns - 20.83 tex and 16.67 tex were set. Then the qualities of the yarns prepared were tested and compared with yak wool yarns spun by common ring spinning. Finally corresponding knitted fabrics were further produced and tested for wearability.
Przemysł włókienniczy zainteresowany jest produkcją przędzy z jaków dzięki jej dobrej właściwości termicznej, przyjaznych ekologicznie warunkom hodowli i niskim cenom. Jednakże przetwarzanie wełny jaków jest trudne ze względu na duże rozrzuty właściwości tych włókien i ich sztywność co uwidacznia się szczególnie przy przędzeniu wełny jaków o dużych masach liniowych. Dla rozwiązania tego zagadnienia opracowano specjalny system przędzenia oparty na przędzeniu kompaktowym z zastosowaniem wydrążonego wałka ze stali kwasoodpornej ze szczeliną o odpowiedniej strukturze na jego powierzchni. Przedstawiono wytwarzanie przędz o masie liniowej ok. 20,8 tex i 16,7 tex. Właściwości wyprzędzionych przędź porównano z właściwościami przędz otrzymanych za pomocą konwencjonalnego przędzenia obrączkowego. Badania zakończono wyprodukowaniem i sprawdzeniem właściwości użytkowych różnych wyrobów dziewiarskich.
Źródło:
Fibres & Textiles in Eastern Europe; 2016, 1 (115); 30-35
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Insensitive RDX by Suspension Spray Technology and Its Characterization
Autorzy:
Yan, Xiang
Li, Xiao Dong
Zhou, Peng
Ji, Wei
Shi, Xiao Feng
Powiązania:
https://bibliotekanauki.pl/articles/358585.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
RDX
Estane 5703
suspension spray technology
detonation velocity
insensitivity
Opis:
A new insensitive and high energy explosive based on RDX was prepared by suspension spray technology using Estane 5703 as a binder (e-RDX). Scanning electron microscopy was used to characterize the morphology and particle size of the samples. The composite was analyzed by differential scanning calorimetry and X-ray photoelectron spectroscopy. Its impact sensitivity and detonation velocity were determined. For comparison, raw RDX, refined RDX (r-RDX) and solution spray dried RDX/Estane 5703 (e1-RDX) were also tested using these five methods. The SEM results showed that the e-RDX size was 1-3 μm. e1-RDX exhibited a spherical shape with some defects on the surface. The XPS results indicated that Estane 5703 can be successfully coated onto the surface of e-RDX. Compared to raw RDX, the drop height of r-RDX, e1-RDX and e-RDX was increased, being 16.5 cm, 32.9 cm and 58.4 cm, respectively. The activation energy of e-RDX is lower than that of raw RDX, but a little higher than that of e1-RDX. Compared to raw RDX, the detonation velocity of r-RDX, e1-RDX, w-RDX and e-RDX had decreased, being 110 m·s–1, 710 m·s–1, 410 m·s–1 and 210 m·s–1, respectively.
Źródło:
Central European Journal of Energetic Materials; 2019, 16, 2; 216-227
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Threshold effect of economic growth on domestic waste production : evidence from China
Autorzy:
Yang, Li
Wang, Hong-Yan
Yi, Lan
Shi, Xiang-Zhen
Deng, Wei
Powiązania:
https://bibliotekanauki.pl/articles/2203127.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
domestic waste
per capita GDP
source reduction
panel threshold regression model
Opis:
Since the implementation of the compulsory sorting of domestic waste policy in China, the participation rate of residents is low, which leads to the unsatisfactory result of terminal reduction of domestic waste. Therefore, the problem of domestic waste reduction still needs to rely on source reduction. Based on the panel data of 29 provincial capitals in China from 2009 to 2018, this study conducts a comprehensive threshold effect test on per capita GDP and other influencing factors of domestic waste production, conducts panel threshold regression for the factors with threshold value, and explores the nonlinear relationship between per capita GDP and domestic waste production under the influence of different threshold variables. The results show that when the urban population density is less than 272 people/km2, the increase of 1% of per capita GDP will lead to a decrease of 0.251% in the domestic waste production, otherwise, it will lead to an increase of 0.249%; when the per capita consumption expenditure is less than the threshold value of 10,260 yuan/year, the influence coefficient of per capita GDP is 0.155, which increases to 0.207 above the threshold. When the share of tertiary industry is taken as the threshold variable, the two threshold values are 61% and 71% respectively. Through the analysis of control variables, it has been found that population size and amount of courier per capita have significant positive effects on domestic waste production, while gas permeability and the number of non-governmental organizations have significant negative effects.
Źródło:
Archives of Environmental Protection; 2022, 48, 4; 13--24
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Using an Interdigital Micromixer for Separation of In3+ from Zinc Hydrometallurgical Process with D2EHPA as an Extractant
Autorzy:
Li, C.
Jiang, F.
Ju, S.
Peng, J.
Wei, Y.
Zhang, L.
Powiązania:
https://bibliotekanauki.pl/articles/356090.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
interdigital micromixer
solvent extraction
mass transfer coefficient
indium
stripping
Opis:
Experiments were performed in an interdigital micromixer with 30 microchannels (40 μm width of each channel) to separate In3+, Fe3+ and Zn2+ from sulfate solutions using Di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extractant. The effects of pH, extractant concentration and flow rate on the extraction efficiency and flow rate on mass transfer coefficient of In3+, Fe3+ and Zn2+ were investigated. At a phase flow rate of 7.0 mL/min and initial solution pH of 0.423, the extraction efficiency of In3+, Fe3+ and Zn2+ was 99.29%, 3.43% and 2.54%, respectively and mass transfer coefficient of In3+, Fe3+ and Zn2+ was 144.307 s-1,1.018 s-1 and 0.750 s-1. Then, the loaded organic phase was stripped in an interdigital micromixer. At a phase flow rate of 9.0 mL/min and HCl concentration of 160 g/L, stripping efficiency of In3+ was 98.92% and mass transfer coefficient of In3+ was 169.808 s-1, while concentration of Fe3+ and Zn2+ was lower than 0.005 g/L with good separation of In3+ from Fe3+ and Zn2+.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2A; 873-878
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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