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Wyświetlanie 1-33 z 33
Tytuł:
Global behavior of a multi-group SEIR epidemic model with spatial diffusion in a heterogeneous environment
Autorzy:
Liu, Pengyan
Li, Hong-Xu
Powiązania:
https://bibliotekanauki.pl/articles/2134056.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
global stability
multigroup epidemic model
spatial heterogeneity
spatial diffusion
globalna stabilność
wielogrupowy model epidemii
różnorodność przestrzenna
dyfuzja przestrzenna
Opis:
In this paper, we propose a multi-group SEIR epidemic model with spatial diffusion, where the model parameters are spatially heterogeneous. The positivity and ultimate boundedness of the solution, as well as the existence of a global attractor of the associated solution semiflow, are established. The definition of the basic reproduction number is given by utilizing the next generation operator approach, whereby threshold-type results on the global dynamics in terms of this number are established. That is, when the basic reproduction number is less than one, the disease-free steady state is globally asymptotically stable, while if it is greater than one, uniform persistence of this model is proved. Finally, the feasibility of the main theoretical results is shown with the aid of numerical examples for a model with two groups.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 2; 271--283
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and properties of ZrO2 ceramic and Ti-6A-4V alloy vacuum brazed by Ti-28Ni filler metal
Mikrostruktura i właściwości złącza ceramiki Zr02 i stopu Ti-6A-4V lutowanego próżniowo spoiwem Ti-28Ni
Autorzy:
Li, Hong
Liu, Xuan
Huang, Haixin
Powiązania:
https://bibliotekanauki.pl/articles/115028.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
ceramika ZrO2
stop Ti-6A-4V
lutowanie próżniowe
mikrostruktura
połączenie
właściwości mechaniczne
ZrO2 ceramic
Ti-6A-4V alloy
vacuum brazing
interface microstructure
mechanical properties
Opis:
Reliable ceramics/metal joints have an extensive application in the aerospace and biomedical area. However, ZrO2 ceramic has not been investigated systematically compared to the Si3N4 and Al2O3 ceramic. Therefore, successful brazing of ZrO2 ceramic and Ti-6A-4V alloy was achieved by using a binary active Ti-28Ni filler metal in this paper. The effect of holding time on the microstructure of ZrO2 ceramic/filler metal interface and mechanical properties of brazed joints was investigated. The results indicated that the representative interfacial microstructure was ZrO2 ceramic/Ti2O/Ni2Ti4O/Ti-rich phase/ Ti2Ni+α-Ti. With the increase of holding time, the thickness of Ti-rich layer in the interface of ZrO2/Ti-6Al-4V joint decreased obviously due to the diffusion of Ti atoms. Substantial brittle intermetallic compounds Ti2Ni and Ni2Ti4O were formed in the joint, which were detrimental to the mechanical properties of the brazed joints. The maximum shear strength of joint was 112.7 MPa when brazed at 1060 °C for 10 min.
Niezawodne połączenia ceramiki/metalu mają szerokie zastosowanie w przemyśle lotniczym i biomedycznym. Jednak ceramika Zr02 nie była badana systematycznie w porównaniu z ceramiką Si3N4 i Al2O3. W niniejszym artykule przeprowadzono udany proces lutowania ceramiki Zr02 i stopu Ti-6A-4V, który został osiągnięty dzięki zastosowaniu binarnie aktywnego metalu wypełniającego Ti-28Ni. Zbadano wpływ czasu trwania połączenia na mikrostrukturę powierzchni ceramicznej/metalu wypełniającego ZrO2 oraz właściwości mechaniczne lutowanych połączeń. Wyniki wskazują, że reprezentatywną mikrostrukturą międzyfazową była ceramika ZrO2/Ti2O/Ni2Ti4O/faza bogata w Ti/Ti2Ni+α-Ti. Wraz ze wzrostem czasu trwania połączenia, grubość warstwy bogatej w Ti w interfejsie złącza ZrO2/Ti-6AI-4V zmniejszyła się z powodu dyfuzji atomów Ti. W spoinie powstały znaczne kruche związki międzymetaliczne Ti2Ni i Ni2Ti4O, które były szkodliwe dla właściwości mechanicznych lutowanych połączeń. Maksymalna wytrzymałość złącza na ścinanie wynosiła 112,7 MPa po lutowaniu w 1060 °C przez 10 min.
Źródło:
Welding Technology Review; 2019, 91, 10; 35-41
0033-2364
2449-7959
Pojawia się w:
Welding Technology Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An upper bound on the Laplacian spectral radius of the signed graphs
Autorzy:
Li, Hong-Hai
Li, Jiong-Sheng
Powiązania:
https://bibliotekanauki.pl/articles/743035.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
Laplacian matrix
signed graph
mixed graph
largest Laplacian eigenvalue
upper bound
Opis:
In this paper, we established a connection between the Laplacian eigenvalues of a signed graph and those of a mixed graph, gave a new upper bound for the largest Laplacian eigenvalue of a signed graph and characterized the extremal graph whose largest Laplacian eigenvalue achieved the upper bound. In addition, an example showed that the upper bound is the best in known upper bounds for some cases.
Źródło:
Discussiones Mathematicae Graph Theory; 2008, 28, 2; 345-359
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the Determinant of q-Distance Matrix of a Graph
Autorzy:
Li, Hong-Hai
Su, Li
Zhang, Jing
Powiązania:
https://bibliotekanauki.pl/articles/30147229.pdf
Data publikacji:
2014-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
q-distance matrix
determinant
weighted graph
directed graph
Opis:
In this note, we show how the determinant of the q-distance matrix Dq(T) of a weighted directed graph G can be expressed in terms of the corresponding determinants for the blocks of G, and thus generalize the results obtained by Graham et al. [R.L. Graham, A.J. Hoffman and H. Hosoya, On the distance matrix of a directed graph, J. Graph Theory 1 (1977) 85-88]. Further, by means of the result, we determine the determinant of the q-distance matrix of the graph obtained from a connected weighted graph G by adding the weighted branches to G, and so generalize in part the results obtained by Bapat et al. [R.B. Bapat, S. Kirkland and M. Neumann, On distance matrices and Laplacians, Linear Algebra Appl. 401 (2005) 193- 209]. In particular, as a consequence, determinantal formulae of q-distance matrices for unicyclic graphs and one class of bicyclic graphs are presented.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 1; 103-111
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Minimum Spectral Radius of Signless Laplacian of Graphs with a Given Clique Number
Autorzy:
Su, Li
Li, Hong-Hai
Zhang, Jing
Powiązania:
https://bibliotekanauki.pl/articles/30148000.pdf
Data publikacji:
2014-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
clique number
kite graph
signless Laplacian
spectral radius
Opis:
In this paper we observe that the minimal signless Laplacian spectral radius is obtained uniquely at the kite graph $PK_{n-\omega,\omega}$ among all connected graphs with $n$ vertices and clique number $\omega$. In addition, we show that the spectral radius $\mu$ of $PK_{m,\omega}$ $(m\geq1)$ satisfies $$\frac{1}{2}(2\omega-1+\sqrt{4\omega^{2}-12\omega+17})\leq\mu\leq 2\omega-1.$$ More precisely, for $m>1$, $\mu$ satisfies the equation \[ \mu-\omega-\frac{\omega-1}{\mu-2\omega+3}=a_m\sqrt{\mu^2-4\mu}+\frac{1}{t_1}, \] where $a_m=\frac{1}{1-t_1^{2m+3}}$ and $t_{1}=\frac{\mu-2+\sqrt{(\mu-2)^{2}-4}}{2}$. At last the spectral radius $\mu(PK_{\infty,\omega})$ of the infinite graph $PK_{\infty,\omega}$ is also discussed.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 1; 95-102
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Laplacian spectrum of some digraphs obtained from the wheel
Autorzy:
Su, Li
Li, Hong-Hai
Zheng, Liu-Rong
Powiązania:
https://bibliotekanauki.pl/articles/743220.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
digraph
Laplacian matrix
eigenvalue
wheel
Opis:
The problem of distinguishing, in terms of graph topology, digraphs with real and partially non-real Laplacian spectra is important for applications. Motivated by the question posed in [R. Agaev, P. Chebotarev, Which digraphs with rings structure are essentially cyclic?, Adv. in Appl. Math. 45 (2010), 232-251], in this paper we completely list the Laplacian eigenvalues of some digraphs obtained from the wheel digraph by deleting some arcs.
Źródło:
Discussiones Mathematicae Graph Theory; 2012, 32, 2; 255-261
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual-parameter sensing characteristics of a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing
Autorzy:
Li, Hong
Zhang, Haoyue
Song, Yanming
Meng, Fanyong
Zhu, Lianqing
Powiązania:
https://bibliotekanauki.pl/articles/2033955.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
fiber Bragg grating
cross-sensitivity
double peaks
surface pasting
curing
Opis:
A novel technology for the simultaneous and independent measurement of dual parameters is proposed and experimented. By using a single fiber Bragg grating half-pasted by 1C-LV epoxy under different curing conditions, the sensor structure is designed such that the reflective single-peak spectrum splits into a twin-peak spectrum, which makes the FBG spectrum form a natural spectral peak splitting bias. A measurement limitation exists in the FBG sensor packaging at room temperature, which can be solved by the high-temperature cured packaging method. To verify the validity of the theory and methodology, the experimental system is used. In the range from –1000 to +1000 με and from 35 to 75°C, the Bragg wavelength change is relative linear to the strain and temperature. The temperature and strain variations can be independently and simultaneously measured using the split peak, and the deviations of the FBG sensor are ±1°C and ±5 με, respectively. This single FBG sensor can realize dual-parameter measurement, which is valuable for narrow-space health monitoring.
Źródło:
Optica Applicata; 2021, 51, 3; 391-406
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of particle density on the classification efficiency of the static air classifier in Vertical Spindle Mill
Autorzy:
Li, Hong
He, Yaqun
Yang, Jinshan
Zhu, Xiangnan
Peng, Zhen
Xie, Weining
Powiązania:
https://bibliotekanauki.pl/articles/110134.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
static air classifier
classification efficiency
material density
Opis:
In order to investigate the impact of density on the classification behavior of particles in the static classifier of Vertical Spindle Mill, the sensitivity of overflow yield to the increase of air amount for narrowly sized pyrite, carborundum, quartz and coal samples were compared in a lab-scale classifier, respectively. Response surface methodology is used to analyze the combined effect of size and density on the classification. Wide size classification was also conducted and results show that both the yield and R90 of overflow increase with the decreasing of density, and the growth of air amount would also lead them to rise. The Whiten’s model was applied to illustrate the influence of density on the sharpness of classification, corrected cut size and fishhook effect. Results show that material with a lower density would have a higher fishhook effect parameter, classification sharpness and corrected cut size. The increase of air amount would result in a more evident fishhook effect for the high density material. Based on the Whiten’s model, a new classification efficiency model with the addition of particle density in various forms was established. This new model could describe the classification efficiency of materials with different density in the identical experiment conditions.
Źródło:
Physicochemical Problems of Mineral Processing; 2019, 55, 2; 494-503
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabric Treated with Dye Modified TiO2/Graphene Composite and its Photocatalytic and Self-Cleaning Properties
Autorzy:
Wen, Yu-xin
Bao, Li-hong
Ling, Jia-wen
Guan-Fanglan
Mei, Zhang
Nie-Jinmei
Powiązania:
https://bibliotekanauki.pl/articles/2200765.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
dye modified titanium
dioxide composite
graphene composite
treatment method
cotton fabric
photocatalytic self-cleaning
photocatalytic degradation
Opis:
In this paper, a dye modified titanium dioxide/graphene composite (DTG20) was prepared using direct grey D, a dye with good water solubility, as a modifier. Then the DTG20 and its intermediates, including TiO2 and titanium dioxide/graphene (TG), were finished on cotton fabric through the padding, coating and compounding methods, respectively. Photocatalytic properties of the treated fabrics were investigated using the MB simulated pollutant. It was found that the photodegradation efficiency of MB shown by DTG20 finished fabric treated with the compounding method can reach 90.55 %, and after four recycling experiments, the removal rate of MB can still reach 77.07 %. After being exposed to sunlight for 6 hours, the photodegradation efficiency of MB stained on the surface of DTG20 treated fabric can achieve 91.44 %; therefore, it also exhibited an excellent self-cleaning effect.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 5 (151); 53--59
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of vitamins A, E, hematological and serum biochemical markers in Crucian carp (Carassius auratus gibelio) exposed to environmental Pb2+ and Cd2+
Autorzy:
Khan, Sher
Zhou, Peiyuan
Liu, Xiaoyu
Li, Hong
Li, Jingna
Rehman, Zia ur
Ahmad, Ijaz
Powiązania:
https://bibliotekanauki.pl/articles/1039010.pdf
Data publikacji:
2015
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
vitamins A and E
hematology
serum chemistry
Crucian carp (Carassius auratus gibelio)
Cd2+
Pb2+
Opis:
Toxicity of Pb2+ and Cd2+ is a widespread issue in the world; however, few studies have been conducted to understand their effect at environmentally realistic concentration in a mixture. In the present study, Crucian carp was exposed to Pb2+ (30 µg·l-1), Cd2+ (100 µg·l-1) and their mixture (30+100 µg·l-1) for 96 h and 21 d period to assess changes in the liver and muscle vitamin A and E content, and hematological and serum biochemical parameters. The results indicated significant decline in the level of antioxidant vitamins A, E and alterations in the hematological and serum biochemical indices. The toxicity revealed anemia, impairment of the liver and kidney with evident responses after 21 d exposure due to additive effect of Pb2+ and Cd2+ in mixture. Moreover, the differential response of vitamins A, E and blood parameters to low levels of waterborne Pb2+ and Cd2+ in freshwater fish can be used as biomarkers for monitoring contamination of aquatic environment.
Źródło:
Acta Biochimica Polonica; 2015, 62, 3; 581-587
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remaining useful life prediction model of the space station
Model predykcji pozostałego czasu pracy stacji kosmicznej
Autorzy:
Li, Xiaopeng
Huang, Hong-Zhong
Li, Fuqiu
Ren, Liming
Powiązania:
https://bibliotekanauki.pl/articles/301774.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
space station
remaining useful life prediction
key equipment
key activity
Monte Carlo simulation
stacja kosmiczna
przewidywanie pozostałego czasu pracy
kluczowy sprzęt
kluczowe działania
symulacja Monte Carlo
Opis:
Space station is a very complex system, and its remaining useful life will be affected by the key equipment, cosmonauts’ maintenance activities as well as space environments. It is important for the operation management of a space station to predict its remaining useful life (RUL). A valid RUL prediction model is the key foundation for this issue, which motivates the research presented in this paper. Firstly, different types of space station life are defined. Secondly, the function and performance requirements as well as the operation mission program of the space station are analysed, which are further used to confirm the model development precondition. A life prediction model is then proposed by synthetically taking account of the safety, reliability and maintainability restrictions. Finally, the data requirement for supporting the RUL prediction is determined. Based on this work, a comprehensive procedure for RUL prediction model development is constructed for the operation management engineers of the space station. If the data of the development and operation is adequate, RUL prediction of the space station can be well implemented, and can be further leveraged to support the space station operation management.
Stacja kosmiczna stanowi wysoce złożony system, którego pozostały czas pracy (ang. remaining useful time, RUL) zależy od kluczowego sprzętu, czynności konserwacyjnych przeprowadzanych przez kosmonautów, a także warunków panujących w kosmosie. Zarządzanie operacyjne stacją kosmiczną wymaga przewidywania RUL. Podstawą tego zagadnienia jest stworzenie prawidłowego modelu predykcji RUL, co jest przedmiotem niniejszej pracy. W artykule, w pierwszej kolejności, zdefiniowano różne kategorie czasu pracy stacji kosmicznej na orbicie. Następnie, przeanalizowano wymagania dotyczące funkcji i eksploatacji stacji a także program jej misji operacyjnych. Wyniki tych analiz wykorzystano do weryfikacji wstępnych warunków koniecznych do budowy modelu. W dalszej kolejności, zaproponowano model predykcji czasu pracy stacji, który w sposób syntetyczny uwzględnia ograniczenia dotyczące bezpieczeństwa, niezawodności i możliwości konserwacji. Na koniec określono rodzaje danych wspierających predykcję RUL. Na podstawie opisanych etapów prac skonstruowano kompleksową procedurę opracowywania modeli predykcji RUL dla inżynierów zarządzania operacyjnego pracujących na stacjach kosmicznych. Jeśli dane dotyczące rozwoju i operacji są prawidłowe, zaprojektowany algorytm predykcji pozostałego czasu pracy stacji kosmicznej można z powodzeniem zaimplementować, a także rozszerzyć tworząc skuteczne narzędzie wsparcia personelu zarządzającego pracą stacji kosmicznej.
Źródło:
Eksploatacja i Niezawodność; 2019, 21, 3; 501-510
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability evaluation for vhf and uhf bands under different scenarios via propagation loss model
Ocena niezawodności propagacji fal radiowych pasm VHF i UHF w różnych warunkach terenowych z wykorzystaniem modelu utraty mocy sygnału
Autorzy:
Li, Xiang
Huang, Hong-Zhong
Li, Yi-Fan
Li, Yan-Feng
Powiązania:
https://bibliotekanauki.pl/articles/301184.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
propagation
reliability estimation
lognormal distribution
VHF radio propagation
UHF radio propagation
propagacja
ocena niezawodności
rozkład lognormalny
propagacja fal radiowych VHF
propagacja fal radiowych UHF
Opis:
The significant effect of path loss on the reliability of very high frequency (VHF) and ultrahigh frequency (UHF) bands propagation has drawn much attention. Previous works mainly focus on the reliability evaluation for infrastructures and basic equipment, however, its propagation reliability has not been taken into full consideration. This paper proposes a new method for evaluating the reliability of the wireless communication based on the analysis of the traditional outdoor wave propagation loss models. In the reliability evaluation of the radio communication, we firstly consider the transmission frequency, the antenna height, the cell type and the communication distance. Then, we use a lognormal distribution to fit the random distribution curve of the communication distance so that the relationship between the path loss value and the reliability can be analysed. We further derive the probability distribution function (PDF) and the cumulative distribution function (CDF) of the path loss value from different antenna correction factors, cell type correction factors and terrain correction factors. Finally, we calculate the radio communication reliability values at different frequencies based on the threshold of the propagation loss value. Compared with the reliability degree only considering the communication distance threshold, the influence of environmental factors on the reliability of the VHF and the UHF radio propagation has been analysed.
W literaturze przedmiotu, wiele uwagi poświęca się ostatnio znaczącemu wpływowi utraty mocy sygnału (ang. path loss) na niezawodność rozchodzenia się fal tworzących pasma o bardzo wysokiej częstotliwości (VHF) i ultra wysokiej częstotliwości (UHF). Wcześniejsze prace koncentrują się głównie na ocenie niezawodności infrastruktury i podstawowego wyposażenia, nie uwzględniając w pełni niezawodności propagacji fal. W niniejszym artykule zaproponowano nową metodę oceny niezawodności komunikacji bezprzewodowej opartą na analizie tradycyjnych modeli utraty mocy sygnału podczas propagacji fal radiowych w środowisku zewnętrznym. Oceniając niezawodność komunikacji radiowej, w pierwszej kolejności rozważano częstotliwość transmisji, wysokość anteny, typ komórki oraz odległość komunikacyjną. Następnie, za pomocą rozkładu lognormalnego, dopasowano krzywą rozkładu losowego odległości komunikacyjnej, co pozwoliło na analizę związku między wartością utraty mocy sygnału a niezawodnością. W dalszej kolejności, z wartości różnych współczynników korekcji anteny, typu komórki oraz terenu wyprowadzono funkcję rozkładu prawdopodobieństwa oraz dystrybuantę wartości utraty mocy sygnału. Na koniec obliczono wartości niezawodności komunikacji radiowej dla różnych zakresów częstotliwości w oparciu o próg wartości utraty mocy sygnału. Przedstawiona analiza wykracza poza elementarne obliczenia niezawodności na podstawie maksymalnej odległości komunikacyjnej biorąc także pod uwagę wpływ czynników środowiskowych na niezawodność propagacji fal radiowych VHF i UHF.
Źródło:
Eksploatacja i Niezawodność; 2019, 21, 3; 375-383
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Broadband convolutional scattering characteristics of all dielectric transmission Pancharatnam–Berry geometric phase metasurfaces
Autorzy:
Li, Yiyun
Jin, Yongxing
Jing, Xufeng
Shi, Lijiang
Li, Chenxia
Hong, Zhi
Powiązania:
https://bibliotekanauki.pl/articles/2086765.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
grating
metasurface
optical device
Opis:
In order to obtain the broadband scattering characteristics, we propose a superperiodic cell structure with all-dielectric material to construct Pancharatnam–Berry geometric phase encoding metasurfaces. Because we cannot design or prepare infinitesimal coding unit particles, according to the generalized Snell’s law, we can only obtain discrete scattering angle regulation for the basic coding metasurface sequence. In order to obtain multi-angle scattering characteristics, we introduce the Fourier convolution principle in digital signal processing on the Pancharatnam–Berry geometric phase encoding metasurfaces. By using the addition and subtraction operations on two encoding metasurface sequences, a new encoding metasurface sequence can be obtained with different deflection angle. Fourier convolution operations on the encoding metasurfaces can provide an efficient method in optimizing encoding patterns to achieve continuous scattering beams. The addition and subtraction methods are also applicable to the checkerboard coding mode. The combination of Fourier convolution principle and Pancharatnam–Berry phase coded metasurface in digital signal processing can realize more powerful electromagnetic wave manipulation capability.
Źródło:
Optica Applicata; 2022, 52, 2; 297--323
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on speed control of high speed trains based on hybrid modeling
Autorzy:
Hou, Tao
Tang, Li.
Niu, Hong-xia
Zhao, Tingyang
Powiązania:
https://bibliotekanauki.pl/articles/27311802.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
high-speed train
hybrid modeling
speed control
error compensation
pociąg ekspresowy
modelowanie hybrydowe
kontrola prędkości
kompensacja błędów
Opis:
With the continuous improvement of train speed, the automatic driving of trains instead of driver driving has become the development direction of rail transit in order to realize traffic automation. The application of single modeling methods for speed control in the automatic operation of high-speed trains lacks exploration of the combination of train operation data information and physical model, resulting in low system modeling accuracy, which impacts the effectiveness of speed control and the operation of high-speed trains. To further increase the dynamic modeling accuracy of high-speed train operation and the high-speed train's speed control effect, a high-speed train speed control method based on hybrid modeling of mechanism and data drive is put forward. Firstly, a model of the high-speed train's mechanism was created by analyzing the train's dynamics. Secondly, the improved kernel-principal component regression algorithm was used to create a data-driven model using the actual operation data of the CRH3 (China Railway High-speed 3) high-speed train from Huashan North Railway Station to Xi'an North Railway Station of "Zhengxi High-speed Railway," completing the mechanism model compensation and the error correction of the speed of the actual operation process of the high-speed train, and realizing the hybrid modeling of mechanism and data-driven. Finally, the prediction Fuzzy PID control algorithm was developed based on the natural line and train characteristics to complete the train speed control simulation under the hybrid model and the mechanism model, respectively. In addition, analysis and comparison analysis were conducted. The results indicate that, compared to the high-speed train speed control based on the mechanism model, the high-speed train speed control based on hybrid modeling is more accurate, with an average speed control error reduced by 69.42%. This can effectively reduce the speed control error, improve the speed control effect and operation efficiency, and demonstrate the efficacy of the hybrid modeling and algorithm. The research results can provide a new ideal of multi-model fusion modeling for the dynamic modeling of high-speed train operation, further improve control objectives such as safety, comfort, and efficiency of high-speed train operation, and provide a reference for automatic driving and intelligent driving of high-speed trains.
Źródło:
Archives of Transport; 2023, 66, 2; 77--82
0866-9546
2300-8830
Pojawia się w:
Archives of Transport
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three Insensitive Energetic Co-crystals of 1-Nitronaphthalene, with 2,4,6-Trinitrotoluene (TNT), 2,4,6-Trinitrophenol (Picric Acid) and D-Mannitol Hexanitrate (MHN)
Autorzy:
Hong, D.
Li, Y.
Zhu, S.
Zhang, L.
Pang, C.
Powiązania:
https://bibliotekanauki.pl/articles/1063066.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
co-crystal
insensitive energetic material
crystal structure
explosive properties
Opis:
Co-crystallization is proposed as an effective method to alter the physicochemical properties of energetic materials, e.g. density, sensitivity and solubility. As reported in this paper, it was found that 1-nitronaphthalene could form cocrystals with TNT, picric acid and MHN in a 1:1 molecular ratio. The sensitivity and thermal stability of the 1-nitronaphthalene co-crystals was greatly improved compared with that of pure TNT, picric acid and MHN. In addition, the melting points of TNT, picric acid and MHN were lowered through co-crystallization with 1-nitronaphthalene. The electrostatic potential surface of 1-nitronaphthalene, calculated by the DFT method, showed that the electron-rich 1-nitronaphthalene has a tendency to be a proton donor and to co-crystallize with other energetic materials. The structures of the co-crystals of 1-nitronaphthalene with TNT and picric acid were characterized by single crystal X-ray diffraction (SXRD). The 1-nitronaphthalene/MHN co-crystal was studied by powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and FTIR.
Źródło:
Central European Journal of Energetic Materials; 2015, 12, 1; 47-62
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Review of Carbon Emission and Carbon Neutrality in the Life Cycle of Silk Products
Autorzy:
Liu, Shuyi
Liu, Hong
Meng, Yudong
Li, Qizheng
Wang, Laili
Powiązania:
https://bibliotekanauki.pl/articles/2171952.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
carbon footprint
carbon neutrality
silk product
life cycle
Opis:
Silk is a distinctive and significant category of natural structural protein fiber. With a remarkable structure and versatility, silk has emerged as a topic of scientific study perennially because of its chemical, physical and biological properties. Meanwhile, in order to have an omnifaceted understanding of silk, the environmental performance of silk production is also worthy of attention. With the concern of global warming, efforts are increasingly focused on understanding and addressing carbon emission in the life cycle of silk products. However, the majority of current studies give priority to the carbon emission of either just one or a few stages of silk products’ life cycle, or to a specific type of silk product. On the basis of a review of literature on the life cycle assessment of silk products, this study presents a full-scale review of the quantification of the carbon emission and carbon neutrality of cocoon acquisition, industrial production of silk products, distribution, consumption, and recycling. The analysis revealed that the carbon sequestration by photosynthesis at the stage of cocoon acquisition could not be ignored. It is of importance to establish complete and unified system boundaries when quantifying carbon emissions in the industrial production of silk products. Reasonable models of washing times and washing modes are needed to assess carbon emissions in the domestic laundry of silk products. At the end of life phase of silk products, the positive impact on carbon emission in the phase of silk recycling is noteworthy. This study will help interested scholars, manufacturers and consumers to gain an in-depth understanding of the carbon emissions and carbon neutrality of silk products, and it is also of great value for exploring new production processes for reducing carbon emissions of silk products.
Źródło:
Fibres & Textiles in Eastern Europe; 2022, 2 (151); 1--7
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A first-principle study of the effect of Fe/Al impurity defects on the surface wettability of dolomite
Autorzy:
Chen, Hong
Ao, Xianquan
Cao, Yang
Li, Cuiqin
Jiang, Chunyan
Powiązania:
https://bibliotekanauki.pl/articles/2146916.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
density functional theory
phosphate rock flotation
dolomite
surface wettability
density of states
Opis:
The presence of Fe and Al atoms in large quantities in phosphate ores can significantly affect the surface properties of the minerals during flotation. In this study, the effects of Fe/Al impurities on the adsorption of H2O molecules on dolomite, including the density of states (DOS), Mulliken bond group values, and charge groups, were investigated and the adsorption energy was analyzed using density functional theory. The results show that the adsorption of H2O molecules on perfect and Fe/Al-substituted dolomites is weak chemisorption, and the Fe and Al impurities weaken and enhance the adsorption capacity of H2O molecules, respectively. Therefore, the hydrophilicity of the dolomite surface increases in the following order: Fe-substituted dolomite < perfect dolomite < Al-substituted dolomite. The Mulliken charge and bond group analysis shows that the adsorption of H2O molecules on dolomite is primarily through the interaction between Ow and Ca atoms, where the d orbitals of Ca atoms provide charges for Ow atoms to form ionic bonds, which related to the poor electronegativity of Ca atoms and their weak valence electron binding ability. The DOS analysis shows that, during the adsorption of H2O molecules on dolomite, Mg and Al atoms have less influence on the dolomite surface, whereas Fe and Ca atoms undergo competitive adsorption, which inhibits the interaction between Ca atoms and H2O molecules on the dolomite surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 4; art. no. 150702
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Breast Support and Gait Speed on Three-Dimensional Breast Displacement for Women with Small Breasts
Wpływ wsparcia piersi i szybkości chodu na trójwymiarowe przemieszczenie piersi u kobiet z małymi piersiami
Autorzy:
Chen, Xiaona
Sun, Guangwu
Wang, Jianping
Li, Yanmei
Xie, Hong
Powiązania:
https://bibliotekanauki.pl/articles/1419738.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
breast
multiplanar breast displacement
breast suport condition
gait speed
breast movement
piersi
wielopłaszczyznowe przemieszczenie piersi
stan podparcia piersi
prędkość chodu
ruch piersi
Opis:
This paper investigated three-dimensional breast displacement under different breast suport conditions and gait speeds for women with small breasts. The breast coordinates of fifteen female participants with small breasts (sizes ranging from A to C) were recorded during treadmill walking and running tests under two different sports bra conditions and a no bra condition. The results showed that although vertical breast displacement was always the greatest in each condition, mediolateral breast displacement was significantly greater than anteroposterior breast displacement. Mediolateral breast displacement was not effectively reduced in the two sports bra conditions compared to the no bra condition. It is recommended that sports bra designed for women with small breasts should aim to limit mediolateral breast displacement instead of anteroposterior breast displacement, on the premise of controlling vertical breast displacement. The findings also suggest that the effectiveness of sports bras at reducing side-to-side breast movement requires further optimisation.
W pracy zbadano trójwymiarowe przemieszczenie piersi przy różnych warunkach podtrzymywania piersi i szybkości chodu u kobiet z małymi piersiami. Współrzędne piersi piętnastu uczestniczek z małymi piersiami (rozmiary od A do C) rejestrowano podczas testów chodu na bieżni i biegania w stanikach sportowych i bez. Wyniki pokazały, że chociaż pionowe przemieszczenie piersi było zawsze największe w każdym stanie, środkowo-boczne przemieszczenie piersi było znacznie większe, niż przemieszczenie piersi przednio-tylne. Stwierdzono, że biustonosz sportowy nie zmniejszył skutecznie przemieszczenia biustu w bok w porównaniu ze stanem bez stanika. Zaleca się, aby stanik sportowy przeznaczony dla kobiet z małym biustem miał na celu ograniczenie środkowo-bocznego przemieszczenia piersi zamiast przesunięcia piersi w przód i tył, z założeniem kontrolowania pionowego przemieszczenia piersi. Odkrycia sugerują również, że skuteczność staników sportowych w ograniczaniu ruchów piersi na boki wymaga dalszej optymalizacji.
Źródło:
Fibres & Textiles in Eastern Europe; 2021, 2 (146); 87-94
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
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:
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:
Hybrid watermarking scheme based on singular value decomposition ghost imaging
Autorzy:
Wu, Jun-Yun
Huang, Wei-Liang
Wen, Ru-Hong
Gong, Li-Hua
Powiązania:
https://bibliotekanauki.pl/articles/1835818.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
digital watermarking
SVD ghost imaging
discrete wavelet transform
imperceptibility
Opis:
A hybrid watermarking algorithm with an optical watermark image based on singular value decomposition (SVD) ghost imaging is designed. Simultaneously, the blended watermarking algorithm is designed based on 4-level discrete wavelet transform (DWT), discrete cosine transform (DCT) and singular value decomposition (SVD). The 4-level diagonal sub-band image is obtained by performing 4-level two-dimensional wavelet transform on the original image, and the coefficient matrix is produced by applying the discrete cosine transform on the 4-level diagonal sub-band image. Then, three matrices are obtained by performing the singular value decomposition on the coefficient matrix. In addition, the optical watermark image is encrypted by an SVD ghost imaging system. The system could generate a secret key, and unauthorized users could not decrypt and reconstruct the original watermark image without this key. Later the encrypted watermark image is generated into the other three matrices by singular value decomposition. Afterwards, the encrypted watermark is embedded in the host image by mutual operation of different matrices in the algorithm. Simulation results validate the feasibility of the proposed hybrid watermarking scheme.
Źródło:
Optica Applicata; 2020, 50, 4; 633--647
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Gas6 gene rs8191974 and Ap3s2 gene rs2028299 are associated with type 2 diabetes in the northern Chinese Han population
Autorzy:
Kazakova, Elena
Zghuang, Tianwei
Li, Tingting
Fang, Qingxiao
Han, Jun
Qiao, Hong
Powiązania:
https://bibliotekanauki.pl/articles/1038636.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Type 2 diabetes mellitus
Gas6 gene
Ap3s2 gene
single nucleotide polymorphisms
epidermal growth factor (EGF)-like
Opis:
Previous studies in other countries have shown that single nucleotide polymorphisms (SNPs) in the growth arrest-specific gene 6 (Gas6; rs8191974) and adapter-related protein complex 3 subunit sigma-2 (Ap3s2; rs2028299) were associated with an increasedrisk for type 2 diabetes mellitus (T2DM). However, the association of these loci with T2DM has not been examined in Chinese populations. We performed a replication study to investigate the association of these susceptibility loci with T2DM in the Chinese population.We genotyped 1968 Chinese participants (996 with T2DM and 972controls) for rs8191974 in Gas6 and rs2028299 near Ap3s2, and examined their association with T2DM using a logistic regression analysis. We also analyzed the correlation of genotypes and clinical phenotypes. The distribution of the T allele of SNP rs8191974 in the Gas6 gene was significantly different between T2DM cases and controls when compared with the C allele (P<0.05, OR: 0.80, 95% CI: 0.69-0.94). The occurrence of the CT genotype and the dominant model was also significantly less frequent in the T2DM cases vs. controls when compared with the CC genotype (CT vs. CC: P<0.05, OR: 0.75, 95% CI:0.62-0.90; TT+CT vs. CC: P<0.05, OR:0.75, 95% CI:0.63-0.90). In SNP rs2028299, the allele C showed no statistically significant differencein distribution between the control and T2DM groups when compared with allele A. However, in male populations, the dominant model was statistically more frequent when compared with genotype AA (CC+CA vs. AA: P<0.05, OR:1.29, 95% CI:1.02-1.64), and in obesity-stratified analysis, we also observed a significant difference in the distribution of the dominant model between the T2DM cases and controls in subjects with BMI≥24 kg/m2 and BMI<28kg/m2 (CC+CA vs. AA: P<0.05, OR: 6.33, 95% CI:4.17-9.61). In conclusion, our study shows that SNPsrs8191974 and rs2028299 are significantly associated with T2DM in the Chinese population.
Źródło:
Acta Biochimica Polonica; 2017, 64, 2; 227-231
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability estimation for momentum wheel bearings considering frictional heat
Ocena niezawodności łożysk kół zamachowych z uwzględnieniem ciepła tarcia
Autorzy:
Huang, Hong-Zhong
Yu, Kang
Huang, Tudi
Li, He
Qian, Hua-Ming
Powiązania:
https://bibliotekanauki.pl/articles/1365209.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
momentum wheel bearings
finite element analysis
frictional heat
stress-strength interference model
łożyska kół zamachowych
analiza MES
ciepło tarcia
model obciążeniowo-wytrzymałościowy
Opis:
Momentum wheels are the key components of the inertial actuators in the satellites, and the momentum wheel bearings are weak links of momentum wheels as they operate under harsh conditions. The reliability estimation for momentum wheel bearings are helpful to guarantee the mission successes for both momentum wheels and satellites. Hence, this paper put emphasis into reliability estimation of a momentum wheel bearing considering multiple coupling operating conditions and frictional heat by using the finite element analysis. The stress-strength interference model is employed to calculate the reliability of the momentum wheel bearing. A comparative analysis for reliability estimation with and without frictional heat of the momentum wheel bearing is conducted. The results show that the frictional heat cannot be ignored in the reliability analysis of momentum wheel bearings.
Koła zamachowe są kluczowymi elementami składowymi siłowników bezwładnościowych w satelitach. Ich łożyska stanowią słaby punkt podczas pracy w trudnych warunkach. Ocena niezawodności łożysk kół zamachowych pozwala zapewnić powodzenie misji zarówno w odniesieniu do samych kół zamachowych, jak i satelitów. Dlatego też niniejszy artykuł poświęcono zagadnieniu oceny niezawodności łożyska koła zamachowego z wykorzystaniem analizy metodą elementów skończonych przy uwzględnieniu wielu sprzężonych warunków pracy oraz ciepła tarcia. Do obliczenia niezawodności łożyska koła zamachowego zastosowano model obciążeniowo-wytrzymałościowy. Przeprowadzono także analizę porównawczą oceny niezawodności łożyska koła zamachowego z uwzględnieniem lub bez uwzględnienia ciepła tarcia. Wyniki pokazują, że w analizie niezawodności łożysk kół zamachowych nie można pominąć ciepła tarcia.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 1; 6-14
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on fluoride fixation effect of Bayan Obo rare earth iron ore and three sodium agents under microwave irradiation
Autorzy:
Guo, Jing
Wen, Ming
Li, Jie
Hong, Xunhai
Zhang, Wenhao
Wang, Yonglun
Powiązania:
https://bibliotekanauki.pl/articles/2146846.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
Bayan Obo rare earth iron ore
microwave roasting
sodium agent fluoride fixation
Opis:
To investigate the fluorine fixation of Bayan Obo rare-earth iron ores in beneficiation and metallurgy processes, the effect of three sodium agents, namely, sodium hydroxide, sodium carbonate, and sodium bicarbonate, on fluorine fixation under the action of microwaves was investigated using Xray diffraction, chemical detection, and orthogonal experiments. The effects of different types of sodium, roasting temperatures, sodium ratios, and roasting times on the fluorine fixation rate were evaluated. Results show that compared with conventional roasting, the fluorine fixation efficiency of Bayan Obo rare-earth iron ore under the action of microwave is superior after the formulation of the sodium agent, which is crucial for the study. Among the three sodium agents, the fluorine fixation effect of NaHCO3 can be used as the preferred sodium agent. Orthogonal experiments showed that the factors influencing the magnitude of the fluorine fixation rate are the roasting temperature, sodium agent ratio, and roasting constant temperature time in the order of priority. The optimal conditions for the fluorine fixation process are the microwave roasting temperature of 973.15 K, sodium bicarbonate ratio of 40%, and roasting time of 60 min. The highest fluorine fixation rate of 86.72% can be obtained. The findings of this study can provide a reference for the development of green and economic recovery processes for Bayan Obo rare-earth iron ores.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 1; 63--76
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of bonding condition on mechanical performance of synthetic sports surfaces by FEM
Autorzy:
Wang, Hong
Zheng, Weitao
Liu, Gan
Guo, Zhihao
Han, Rui
Li, Duo
Powiązania:
https://bibliotekanauki.pl/articles/2200836.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
bonding condition
synthetic sports surface
finite element method
Opis:
The purpose of the study was to evaluate the effect of interlayer bonding conditions on the mechanical performance of a synthetic sports track with time. A two-dimensional finite element model of the synthetic sports track was developed in order to calculate the track temperature stress and strain in thermal environmental conditions. Thermal and structural responses of the multi-layer sports ground were simulated using a transient thermal and structural analysis in one day. Based on that, different physical parameters of the interlayer were considered to analyze the influence of the bonding layer status on the potential damage of the surface layer in the sports track. The results indicated that different bonding conditions would affect the strain difference between the top and bottom of the synthetic sports layer, which might cause a weak mechanical performance of the synthetic sports layer. Finally, 2D finite element analysis was regarded to be a proper tool to simulate the transient thermal and mechanical behavior of the synthetic sports track. The suggested simulation model can predict the influence of bonding conditions on damage of the synthetic sports track, which can provide some guidance for engineers and technicians working on constructions of synthetic sports tracks.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 4; 637--647
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
HBx and SP1 upregulate DKK1 expression
Autorzy:
Peng, Hong
Li, Yongguo
Liu, Yunzhi
Zhang, Jingnan
Chen, Ke
Huang, Ailong
Tang, Hua
Powiązania:
https://bibliotekanauki.pl/articles/1038681.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
HCC
HBV
DKK1
SP1
Opis:
Numerous evidences suggested that the hepatitis B virus (HBV) was recognized as an important factor in the development of hepatocellular carcinoma (HCC). Dickkopf-1 (DKK1) recently was reported to be involved in the progress of HCC. HBV may regulate DKK1 expression in hematoma carcinogenesis. Here, we demonstrated that HBV could regulate DKK1 promoter activity which resulted in upregulation of its mRNA and protein expression in several HBV existing cell lines, and HBx played a prominent role in this process. Transcription factor binding site search result showed that there is a SP1 site in DKK1 promoter region. Luciferase assay showed that overexpression of SP1 could increase DKK1 promoter activity in a dose dependent manner. Accordingly, siRNA inhibition of SP1 expression reduced DKK1 promoter activity and decreased the expression of DKK1 protein.
Źródło:
Acta Biochimica Polonica; 2017, 64, 1; 35-39
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Teacher stress among public primary and secondary schoolteachers in Datong, a city of Shanxi Province, China: association between teacher stress and standardized workload
Autorzy:
Zhang, Xiaojuan
Guo, Jungang
Ma, Li
Xu, Ruijun
Wang, Jinfang
Yang, Yonghong
Shen, Hong
Powiązania:
https://bibliotekanauki.pl/articles/2203017.pdf
Data publikacji:
2023-05-23
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
stress
occupational health
China
workload
primary and secondary schoolteachers
occupational health strategy
Opis:
Objectives The policy of the standardized workload has been implemented among primary and secondary schoolteachers in Shanxi Province. The aim of this cross-sectional cohort study is to assess teacher stress among primary and secondary schoolteachers in Datong, a city of Shanxi Province and the association between teacher stress and the quantified workload. Material and Methods Three hundred and fifty schoolteachers in 10 public primary schools, 187 schoolteachers in 6 secondary schools and 268 non-teachers in 21 education institutes were recruited. A single-item rating assessment of work-related stress was completed by using the Exposure to Job Stress measure with modification. The quantified workload included class size, teaching hours, and subjects. Descriptive and logistic regression analyses were carried out. Results In 805 participants, the pro- portion of primary and secondary schoolteachers with moderate stress was significantly greater. The results of Spearman’s correlation and logistic regression analyses showed that the occupations of the primary and secondary schoolteachers had higher stress risk. Further, the stratified results showed that among the primary schoolteachers, the independent stress risk factor was larger class size; while among the secondary schoolteachers, the stress associated factor was more weekly teaching hours. Conclusions After standardization of the workload, there remain higher levels of work stress among primary and secondary schoolteachers. Notwithstanding, the stress state in teachers is manageable and they may be faced with controllable stressors.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2023, 36, 2; 161-176
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reliability assessment of wind turbine generators by fuzzy universal generating function
Autorzy:
Huang, Tudi
Xiahou, Tangfan
Li, Yan-Feng
Qian, Hua-Ming
Liu, Yu
Huang, Hong-Zhong
Powiązania:
https://bibliotekanauki.pl/articles/1841742.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
reliability assessment
double fed induction generator
multi-state system
fuzzy universal generating function
Opis:
Wind power has been widely used in the past decade because of its safety and cleanness. Double fed induction generator (DFIG), as one of the most popular wind turbine generators, suffers from degradation. Therefore, reliability assessment for this type of generator is of great significance. The DFIG can be characterized as a multi-state system (MSS) whose components have more than two states. However, due to the limited data and/or vague judgments from experts, it is difficult to obtain the accurate values of the states and thus it inevitably contains epistemic uncertainty. In this paper, the fuzzy universal generating function (FUGF) method is utilized to conduct the reliability assessment of the DFIG by describing the states using fuzzy numbers. First, the fuzzy states of the DFIG system’s components are defined and the entire system state is calculated based the system structure function. Second, all components’ states are determined as triangular fuzzy numbers (TFN) according to experts’ experiences. Finally, the reliability assessment of the DFIG based on the FUGF is conducted.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 2; 308-314
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comprehensive Analysis of Metal Deformation Law Based on Numerical Simulation of Cold Rolling Process
Autorzy:
Yan, Zhu-Wen
Wang, Bao-Sheng
Bu, He-Nan
Li, Hao
Hong, Lei
Zhang, Dian-Hua
Powiązania:
https://bibliotekanauki.pl/articles/2106570.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
3D elastic-plastic FEM
work roll deflection
lateral thickness
flatness regulation effect
rolling pressure
Opis:
Through taking the cold rolling process as the research object, the three-dimensional finite element model of the strip rolling process is established by using ANSYS/LS-DYNA software. The actual rolling product data has strong consistency with the finite element simulation results. The rolling process is dynamically simulated, and the distribution curves of important rolling parameters such as equivalent stress, control efficiency coefficient, transverse rolling pressure, lateral thickness and work roll deflection is obtained. Based on summarizing the influence of rolling parameters on rolling deformation, the research results of this paper can play an important role in the actual rolling process control. The research results have certain guiding significance for the development and optimization of the rolling control system.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 2; 623--635
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ethnobotany of Acorus in China
Autorzy:
Shu, H.
Zhang, S.
Lei, Q.
Zhou, J.
Ji, Y.
Luo, B.
Hong, L.
Li, F.
Liu, B.
Long, C.
Powiązania:
https://bibliotekanauki.pl/articles/59160.pdf
Data publikacji:
2018
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
In China, species in the genus Acorus are used for many different purposes, viz., in traditional medicine, for rituals, and as ornamental plants. Acorus calamus (sweet flag) has been a symbolic plant in Chinese culture for many centuries and is used as a ceremonial object in festivals throughout the country. For other Acorus species in China, ethnobotanical records are few. During field investigations from 2006 to 2017, we interviewed 573 individuals representing ethnic groups such as the Miao, Yao, Buyi, Shui, Tujia, Dong, She, Maonan, Zhuang, Yi, and Han people. Various ethnobotanical approaches were adopted in the field surveys, including key informant interviews, semistructured interviews, participatory observation, direct observation, etc. The results have revealed a rich treasure trove of traditional knowledge on Acorus in China. Two species (A. macrospadiceus and A. gramineus) were used by ethnic groups as spices to add flavor to meat. Through the study found that all the species of Acorus had medicinal value, especially A. tatarinowii, deafness, blindness, and digestive disorders were among the conditions commonly treated using these plants. Traditional knowledge of the cultural, ethnomedicinal, and food values of Acorus, based on our recent literature surveys and field investigations in China is presented here. A better understanding of Acorus is vital for conserving the plants and the traditional knowledge associated with them.
Źródło:
Acta Societatis Botanicorum Poloniae; 2018, 87, 2
0001-6977
2083-9480
Pojawia się w:
Acta Societatis Botanicorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phyllodulcin Protects PC12 Cells Against the Injury Induced by Oxygen and Glucose Deprivation-Restoration
Autorzy:
Hu, Chang-Long
Ge, Lu
Tang, Yong
Li, Jie
Wu, Chun-Hui
Hu, Jiang-Hong
Yuan, Jin-Tao
Fan, Yong-Zhong
Powiązania:
https://bibliotekanauki.pl/articles/895391.pdf
Data publikacji:
2019-12-29
Wydawca:
Polskie Towarzystwo Farmaceutyczne
Tematy:
apoptosis
oxidative stress
PC12 cells
phyllodulcin
oxygen and glucose deprivation/restoration
Opis:
Phyllodulcin is a natural coumarin derivative found in Hydrangea macrophylla. To discover effective therapeutics for cerebral ischemia-reperfusion injury, we investigated the protective effects of phyllodulcin on PC12 cells injury induced by oxygenation and glucose deprivation/restoration (OGD/R). As a result, phyllodulcin can improve the cell viability and attenuate the extracellular lactate dehydrogenase release. Meanwhile, phyllodulcin can ameliorate the dysfunction of mitochondria through reducing reactive oxygen species production, decreasing the intracellular calcium level and increasing the mitochondrial membrane potential. ROS-associated OGD/R can induce cell apoptosis through the mitochondrial pathway. Phyllodulcin can inhibit apoptosis of PC12 cells through down-regulation of Caspase-3 and Bax as well as up-regulation of Bcl-2. These results indicate phyllodulcin can protect PC12 cells against the damage induced by OGD/R. This investigation gives promising evidences for the therapy of cerebral ischemia-reperfusion injury.
Źródło:
Acta Poloniae Pharmaceutica - Drug Research; 2019, 76, 6; 1043-1050
0001-6837
2353-5288
Pojawia się w:
Acta Poloniae Pharmaceutica - Drug Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of differential serum expression of three factors and pulmonary function in patients with silicosis
Autorzy:
Zhu, Ying
Duan, Xia Yu
Cheng, Yun Qi
Yao, Xin Jing
Xu, Hong
Zhang, Kui Sheng
Li, Feng Shi
Yang, Fang
Liu, Liang He
Yuan, Xiang Ju
Powiązania:
https://bibliotekanauki.pl/articles/2086531.pdf
Data publikacji:
2021-08-05
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
silicosis
pulmonary function
early diagnosis
ROC
PTPN2
factor B
Opis:
ObjectivesSilicosis is a chronic occupational lung disease. As was previously found by the authors, some proteins increased in the lung tissue of activated rats, and protein tyrosine phosphatase non-receptor type 2 (PTPN2), factor B, and vaccinia-related kinase 1 (VRK1) showed highly differential expressions.Material and MethodsIn this study, serum and bronchoalveolar lavage fluid samples were collected from patients with silicosis and healthy people to verify the expression of PTPN2, factor B, and VRK1. The diagnostic value of differentially expressed proteins for silicosis was judged.ResultsThe expression levels of serum PTPN2, VRK1, and factor B in patients with silicosis were significantly higher than those in the control group (p < 0.01). Higher serum PTPN2 and factor B concentrations significantly and negatively correlated with the ratio of forced expiratory volume in 1 s to forced vital capacity (FEV1/FVC), maximum vital capacity (VCmax), FEV1, and FVC, suggesting that the high expression of PTPN2 and factor B is associated with decreased pulmonary ventilation function and restrictive ventilatory impairment in patients with silicosis. All area under curve (AUC) measurements generated from single detection events were >0.744, with PTPN2 reaching the highest value (0.858). The AUC, sensitivity, and specificity for the combined diagnosis using factor B and PTPN2 were 0.907, 86.91% and 85.07%, respectively, for factor B and PTPN2. The 3 differentially expressed proteins are potential classes of predictive biomarkers for silicosis.ConclusionsRegarding the economy and test practicality, the best diagnostic combination is factor B and PTPN2 for the analysis of AUC, sensitivity and specificity.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2021, 34, 4; 527-540
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cellular internalization analysis of folatetargeted PLA-PEG filomicelles loaded with new betulin derivative
Autorzy:
Paduszyński, Piotr
Jelonek, Katarzyna
Kasperczyk, Janusz
Li, Suming
Nguyen, Thi Hong Nhung
Orchel, Janusz
Chodurek, Ewa
Jaworska-Kik, Marzena
Chrobak, Elwira
Bębenek, Ewa
Boryczka, Stanisław
Jarosz-Biej, Magdalena
Smolarczyk, Ryszard
Foryś, Aleksander
Powiązania:
https://bibliotekanauki.pl/articles/285051.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Polskie Towarzystwo Biominerałów
Źródło:
Engineering of Biomaterials; 2019, 22, no.153; 67
1429-7248
Pojawia się w:
Engineering of Biomaterials
Dostawca treści:
Biblioteka Nauki
Artykuł
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