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Wyświetlanie 1-24 z 24
Tytuł:
Fabrication of YSZ coatings on nickel-based alloys by anodic electrophoretic deposition
Autorzy:
Binxia, Yuan
Tianzhong, Chen
Yongzhi, Shang
Haibo, Xue
Min, Li
Powiązania:
https://bibliotekanauki.pl/articles/2204142.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
YSZ coating
anodic electrophoretic deposition
suspension solution
nickel-based alloys
Opis:
In the paper, YSZ coatings were prepared on nickel-based alloy substrates by anodic electrophoretic deposition. The YSZ suspension solution was obtained under stirring and ultrasonic treatment, in which the anhydrous ethanol and acetylacetone were used as the dispersion medium and ammonium polyacrylate was used as the dispersant of the suspension. The effects of different deposition voltage and deposition time on YSZ coating were investigated. Meantime, the microstructure of the coating surface was observed by metallographic microscope. It was found that the high-quality YSZ coating could be obtained by deposition at 60 V for 2–3 min. Finally, the effect of sintering temperature on coating quality was investigated by X-ray diffractometer and scanning electron microscopy. The results showed that the YSZ coating bonded closely with the substrate after sintering at 1200 °C, and the porosity of the YSZ coating increased after sintering.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 1; 8--11
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On an interval-partitioning scheme
Autorzy:
Neuts, Marcel
Li, Jian-Min
Pearce, Charles
Powiązania:
https://bibliotekanauki.pl/articles/1338794.pdf
Data publikacji:
1999
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
random partitioning
spacings
Opis:
In a recent paper, Neuts, Rauschenberg and Li [10] examined, by computer experimentation, four different procedures to randomly partition the interval [0,1] into m intervals. The present paper presents some new theoretical results on one of the partitioning schemes. That scheme is called Random Interval (RI); it starts with a first random point in [0,1] and places the kth point at random in a subinterval randomly picked from the current k subintervals (1
Źródło:
Applicationes Mathematicae; 1999, 26, 3; 347-355
1233-7234
Pojawia się w:
Applicationes Mathematicae
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:
The critical trait of digital entrepreneur: mixed methods research
Autorzy:
Chuang, Li-Min
Lee, Yu-Po
Chang, Yu-Ju
Powiązania:
https://bibliotekanauki.pl/articles/2201960.pdf
Data publikacji:
2023
Wydawca:
Centrum Badań i Innowacji Pro-Akademia
Tematy:
digital entrepreneurship
digital economy
entrepreneurship
entrepreneurs
analytic hierarchy process
AHP
przedsiębiorczość cyfrowa
gospodarka cyfrowa
przedsiębiorczość
przedsiębiorcy
proces hierarchii analitycznej
Opis:
Pioneers of the digital era have invented a different business model and expanded the existence of the digital economy, and the digital entrepreneurship is the beginning of this digital revolution. To explore the key characteristics of digital entrepreneurs, this study is divided into two stages. The first stage conducted a literature review and case study to construct the characteristic elements of the entrepreneurship into a model of digital entrepreneurs. In the second stage, the relative weights of the key characteristics of digital entrepreneurs are understood through an analysis of the AHP questionnaire results. The results show that autonomy and selfdiscipline are keys among the main dimensions of the key characteristics of digital entrepreneurs' entrepreneurship; the secondary dimension of "action power" is key in the main dimension of "autonomy and self-discipline"; the secondary dimension of "business networks" is key in the main dimension of "social capital"; the secondary dimension of "insight" is key in the main dimension of "innovation and breakthrough"; the secondary dimension of "communication ability" is key in the main dimension of "leadership communication".
Źródło:
Acta Innovations; 2023, 46; 5--18
2300-5599
Pojawia się w:
Acta Innovations
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical Spectroscopy of Bearing Steel
Spektroskopia mechaniczna stali łożyskowej
Autorzy:
Lu, X.
Li, W.
Jin, M.
Min, N.
Jin, X.
Powiązania:
https://bibliotekanauki.pl/articles/351791.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bearing steel
twin martensite
mechanical spectroscopy
internal friction
Snoek-Köster peak
stal łożyskowa
bliźniacza struktura martenzytu
atomy węgla
spektroskopia mechaniczna
tarcie wewnętrzne
niskotemperaturowe zbocze szczytu Snoek-Köstera
Opis:
This study presents mechanical spectroscopy of bearing steel subjected to different heat treatments. A non-thermally activated maximum, P1, was found at 130°C, in quenched martensitic samples, which were austenitized at 1050°C and 860°C, and presented twin martensite microstructures. It is suggested that the mechanism of the P1 maximum, observed on the low-temperature side of Snoek-Köster peak, is related to the change of defect configurations in twinned martensite assisted with high mobility of the solute carbon atoms under an external harmonic stress field applied during mechanical loss measurements.
W pracy przedstawiono wyniki badań spektroskopii mechanicznej stali łożyskowej poddanej różnej obróbce cieplnej. W hartowanych martenzytycznych próbkach, które były austenityzowane w 1050°C i 860°C, i posiadały bliźniaczą mikrostrukturę martenzytu, występuje nietermicznie aktywowane maksimum P1 przy 130°C. Sugeruje się, że mechanizm maksimum P1, które występuje na niskotemperaturowym zboczu piku Snoek-Köstera, związane jest ze zmianą konfiguracji defektów w bliźniaczym martenzycie, przy wysokiej ruchliwości atomów węgla. Maksimum P1 ujawnia się pod wpływem działania harmonicznie zmiennego zewnętrznego pola naprężeń przyłożonego do próbki w trakcie badań metodą spektroskopii mechanicznej.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 3A; 2085-2091
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Investigation Of Segregation Of Carbon Atoms Due To Sub-Zero Cryogenic Treatment In Cold Work Tool Steel By Mechanical Spectroscopy And Atom Probe Tomography
Doświadczalne badania segregacji atomów węgla w stali narzędziowej do pracy na zimno po obróbce kriogenicznej metodą spektroskopii mechanicznej i tomografii atomowej
Autorzy:
Min, N.
Li, H. M.
Xie, C.
Wu, X. C.
Powiązania:
https://bibliotekanauki.pl/articles/351716.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cryogenic treatment
isothermal martensite
atom probe tomography
mechanical spectroscopy
Cottrell atmosphere
obróbka kriogeniczna
izotermiczny martenzyt
tomografia atomowa
spektroskopia mechaniczna
atmosfera Cottrella
Opis:
In this work, we present mechanical spectroscopy of cold work tool steel subjected to sub-zero cryogenic soaking treatment to reveal the carbon segregation and the subsequent carbides refinement. The maximum of Snoek-Köster (SK) peak height was obtained in the sample subjected to soaking 1h at −130°C cryogenic treatment. The SK peak height is reduced with prolonging the soaking time. The results indicate that an increase in the height of SK peak is connected with an increase in dislocation density and the number of segregated carbon atoms in the vicinity of dislocations or twin planes after martensite transformation at −130°C which is confirmed by corresponding TEM and atom probe tomography measurement. Hence, it is suggested that the isothermal martensite, formed during the cryogenic soaking treatment decreases (APT) the height of SK peak.
W pracy przedstawiono wyniki spektroskopii mechanicznej stali narzędziowej do pracy na zimno poddanej obróbce kriogenicznej w celu odsłonięcia segregacji węgla i późniejszego tworzenia węglików. Dzięki połączeniu transmisyjnej mikroskopii elektronowej (TEM) i tomografii atomowej (APT) uzyskano maksymalny pik Snoek-Köstera (SK) w próbce poddanej obróbce kriogenicznej przez 1 godzinę w −130°C. Wysokość piku SK obniża się wraz z wydłużeniem czasu obróbki. Wyniki wskazują, że zwiększenie wysokości piku SK jest połączone ze wzrostem gęstości dyslokacji i liczby segregowanych atomów węgla w sąsiedztwie dyslokacji lub płaszczyzn bliźniaczych po przemianie martenzytycznej w -130°C, co potwierdzone jest odpowiednimi pomiarami TEM oraz APT. W związku z tym proponuje się, że izotermiczny martenzyt powstały podczas obróbki kriogenicznej zmniejsza wysokość piku SK.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2A; 1109-1113
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Work stress and the risk of recurrent coronary heart disease events: A systematic review and meta-analysis
Autorzy:
Li, Jian
Zhang, Min
Loerbroks, Adrian
Angerer, Peter
Siegrist, Johannes
Powiązania:
https://bibliotekanauki.pl/articles/2176999.pdf
Data publikacji:
2015-02-24
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
work stress
recurrence
coronary heart disease
meta-analysis
epidemiology
prospective studies
Opis:
Though much evidence indicates that work stress increases the risk of incident of coronary heart disease (CHD), little is known about the role of work stress in the development of recurrent CHD events. The objective of this study was to review and synthesize the existing epidemiological evidence on whether work stress increases the risk of recurrent CHD events in patients with the first CHD. A systematic literature search in the PubMed database (January 1990 – December 2013) for prospective studies was performed. Inclusion criteria included: peer-reviewed English papers with original data, studies with substantial follow-up (> 3 years), end points defined as cardiac death or nonfatal myocardial infarction, as well as work stress assessed with reliable and valid instruments. Meta-analysis using random-effects modeling was conducted in order to synthesize the observed effects across the studies. Five papers derived from 4 prospective studies conducted in Sweden and Canada were included in this systematic review. The measurement of work stress was based on the Demand- Control model (4 papers) or the Effort-Reward Imbalance model (1 paper). According to the estimation by meta-analysis based on 4 papers, a significant effect of work stress on the risk of recurrent CHD events (hazard ratio: 1.65, 95% confidence interval: 1.23–2.22) was observed. Our findings suggest that, in patients with the first CHD, work stress is associated with an increased relative risk of recurrent CHD events by 65%. Due to the limited literature, more well-designed prospective research is needed to examine this association, in particular, from other than western regions of the world.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2015, 28, 1; 8-19
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Facile Synthesis and Characterization of Novel CdS/BiOI Heterojunctions with Enhanced Visible-Light Photocatalytic Performances
Autorzy:
Fang, Shanshan
Lu, Min
Zhou, Man
Li, Zhongyu
Xu, Song
Peng, Yanyan
Li, Qinchi
Lu, Dayong
Powiązania:
https://bibliotekanauki.pl/articles/1030343.pdf
Data publikacji:
2017-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
CdS/BiOI heterojunctions
visible-light photocatalyst
photocatalytic activity
nanocomposites
Opis:
Novel CdS/BiOI heterojunction photocatalysts were successfully prepared by facile method. The as-prepared samples were characterized by transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, the Raman spectroscopy, UV-vis diffuse reflectance spectra, the Fourier transform infrared spectra, and photoluminescence. It was found that CdS nanoparticles were uniformly distributed on the surface of BiOI microspheres. The photodegradation tests showed that the photocatalytic efficiency was increased at first and then decreased when further increasing CdS content in the nanocomposites. The highest activity was obtained by 3%-CdS/BiOI nanocomposites. The enhanced photocatalytic performances were attributed to the matched band potentials of CdS and BiOI, which resulted in the efficient separation of photogenerated electron-hole pairs. Based on the experimental results, a reasonable photocatalytic mechanism of CdS/BiOI photocatalysts was also proposed.
Źródło:
Acta Physica Polonica A; 2017, 131, 2; 263-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pore structure and surface properties of diatomite with mechanical grinding and its influence on humidity control
Autorzy:
Hu, Zhibo
Zheng, Shuilin
Li, Jinyu
Zhang, Shuaiqian
Liu, Min
Wang, Zhicheng
Li, Jiaxin
Sun, Hongjuan
Powiązania:
https://bibliotekanauki.pl/articles/2175445.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
diatomite
mechanical grinding
pore structure
surface properties
humidity control performance
Opis:
Mechanical grinding (MG) is an effective method to regulate the pore structure and surface properties of mineral material. Grinding diatomite samples were prepared by horizontal sander under different grinding time. The pore structure and surface properties of grinding samples were characterized systematically by the particle size analysis, low temperature nitrogen adsorption, MIP, fractal theory, XRD, SEM, TEM, FTIR and surface hydroxyl density analysis. The humidity control performance (HCP) of grinding diatomite was tested under different temperature and relative humidity. The relationship among pore structure, surface properties and HCP was analyzed. The results show that macroporous is more easily damaged by mechanical force than mesoporous, and the internal blind holes structure can be opened. The HCP of diatomite is positively correlated with the specific surface area, mesoporous volume, the inhomogeneity of macroporous structure and the number of hydroxyl groups, while negatively correlated with the proportion of macroporous volume.
Źródło:
Physicochemical Problems of Mineral Processing; 2022, 58, 6; art. no. 153509
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-grade mutant OmpF induces decreased bacterial survival rate
Autorzy:
Zhao, Zhi-ping
Liu, Ting-ting
Zhang, Li
Luo, Min
Nie, Xin
Li, Zai-xin
Pan, Yu
Powiązania:
https://bibliotekanauki.pl/articles/1039304.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
antibiotic resistance
mOmpF
OmpF
outer membrane protein
bacterial survival rate
Opis:
OmpF plays very important roles in the influx of antibiotics and bacterial survival in the presence of antibiotics. However, high-grade mutant OmpF and its function in decreasing bacterial survival rate have not been reported to date. In the present study, we cloned a high-grade mutant OmpF (mOmpF) and sequence analysis suggested that over 45 percent of the DNA sequence was significantly mutated, leading to dramatic changes in over 55 percent of the amino acid sequence. mOmpF protein was successfully expressed. When grown in the presence of antibiotic, the bacterial survival rate decreased and the antibiotic inhibition zone became larger with the increase of the mOmpF. It was concluded that concentration of high-grade mutant mOmpF dramatically influenced the bacterial survival rate. The study presented here may provide insights into better understanding of the relationships between structure and function of OmpF.
Źródło:
Acta Biochimica Polonica; 2014, 61, 2; 369-373
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cracking control technique for continuous steel-concrete composite girders under negative bending moment
Autorzy:
Cai, Min
Li, Wenjie
Wan, Zhiyong
Sheng, Jianjun
Tan, Juliang
Ma, Chao
Powiązania:
https://bibliotekanauki.pl/articles/27312132.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
dźwigar ciągły
dźwigar zespolony
dźwigar stalowo-betonowy
odporność na pękanie
wzmocnienie
beton ultra wysokiej wartości
continuous girder
steel-concrete composite girder
hogging moment
cracking control
strengthening
ultra high performance concrete
Opis:
Continuous steel-concrete composite girder can fully utilize material strength and possess large spanning ability for bridge constructions. However, the weak cracking resistance at the negative bending moment region of the girder seriously harms its durability and serviceability. This paper investigates practical techniques to improve the cracking performance of continuous steel-concrete composite girders subjected to hogging moment.Areal continuous girderwas selected as the background bridge and introduced for numerical analysis. Modeling results show that under the serviceability limit state, the principle stress of concrete slabs near the middle piers of the bridgewas far beyond the allowable material strength, producing a maximum tensile stress of 10.0 MPa. Approaches for strengthening concrete decks at the negative moment region were developed and the effectiveness of each approach was assessed by examing the tensile stress in the slabs. Results indicate that the temporary counterweight approach decreased the maximum tensile stress in concrete slabs by 22%. Due to concrete shrinkage and creep, more than 65% of the prestressed compressive stresses in concrete slabs were finally dispersed to the steel beams. A thin ultra-high performance concrete (UHPC) overlay at the hogging moment region effectively increased the cracking resistance of the slabs, and practical engineering results convicted the applicability of the UHPC technique.
Źródło:
Archives of Civil Engineering; 2023, 69, 3; 239--251
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on synthesis and photoelectric properties of AgInS2 quantum dots
Autorzy:
Yuan, Binxia
Luo, Zige
Sun, Yongjun
Cao, Sheng
Cao, Lan
Li, Min
Powiązania:
https://bibliotekanauki.pl/articles/2106479.pdf
Data publikacji:
2022
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
AgInS
Quantum dots
Optical properties
Photocatalytic hydrogen production
Opis:
AgInS2 Quantum dots (AIS QDs) have high quantum yield and catalytic performance, which is promising materials in photo-catalytic and optoelectronic fields. In the paper, it adopted a simple and non-toxic method to synthesize AIS QDs. The effect of reaction temperature on the growth mechanism, optical and physical properties of AIS had been extensively investigated by using L-cysteine as the sulfur source, and their application in catalytic hydrogen production was also studied. The results demonstrated that the fluorescence properties will be quenched with the increase of temperature, indicating that the separation speed of electron hole pairs of samples obtained at higher temperature was faster. Meantime, the electron transport capacity and the photocurrent had also improved with the increase of reaction temperature. Finally, the sample obtained at 100 oC had higher hydrogen production rate.
Źródło:
Polish Journal of Chemical Technology; 2022, 24, 2; 21--26
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Amino acid substitutions of His296 alter the catalytic properties of Zymomonas mobilis 10232 levansucrase
Autorzy:
Li, Shu
Chen, Ming
Li, Gang
Yan, Yong
Yu, Hai
Zhan, Yu
Peng, Zi
Wang, Jin
Lin, Min
Powiązania:
https://bibliotekanauki.pl/articles/1040841.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Zymomonas mobilis
His296
levansucrase
levan
transfructosylation activity
hydrolysis activity
Opis:
His296 of Zymomonas mobilis levansucrase (EC 2.4.1.10) is crucial for the catalysis of the transfructosylation reaction. The three-dimensional structures of levansucrases revealed the His296 is involved in the substrate recognition and binding. In this study, nine mutants were created by site-directed mutagenesis, in which His296 was substituted with amino acids of different polarity, charge and length. The substitutions of His296 with Arg or Trp retained partial hydrolysis and transfructosylation activities. The positively charged Lys substitution resulted in a 2.5-fold increase of sucrose hydrolysis. Substitutions with short (Cys or Ser), negatively charged (Glu) or polar (Tyr) amino acids virtually abolished both the activities. Analysis of transfructosylation products indicated that the mutants synthesized different oligosaccharides, suggesting that amino acid substitutions of His296 strongly affected both the enzyme activity and transfructosylation products.
Źródło:
Acta Biochimica Polonica; 2008, 55, 1; 201-206
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Preheating Temperature on Microstructure and Optical Properties of ZnO Thin Films Prepared by Sol-Gel Spin Coating Technique
Autorzy:
Ji, Qiang-min
Wang, Ya-li
Gao, Xiao-yong
Gao, Hui
Zhai, Yao-fei
Powiązania:
https://bibliotekanauki.pl/articles/1398971.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.55.-m
Opis:
Highly-oriented ZnO thin films prepared by using low-cost technique such as sol-gel technique are of much importance to ZnO-based white light-emitting diodes. The chose of proper preheating temperature in sol-gel technique is still critical for highly-oriented ZnO thin film so far. The mechanisms for the preheating in the formation of ZnO thin film and for the reactions involved in the sol solution have not been clearly stated yet. Thus, in this work, the highly-oriented ZnO thin films were prepared on glass substrates by using sol-gel spin-coating technique. The sol solution was prepared by using the two-step method rather than usual one-step method, which facilitates the understanding of the mechanism for the reactions involved in the sol solution. The effect of the preheating temperature on the microstructure and the optical properties of the films were in particular investigated. The mechanisms for the preheating in the formation of the films and for the reactions involved in the sol solution prepared by the two-step method were also proposed in terms of the experimental results. The preheating not only enhances the volatilization of the solvent 2-methoxyethanol and the decomposition of the residual organic species, but also results into the formation of small number of ZnO particles. The preheating temperature of 300°C is most favorable for the highly-oriented ZnO thin film. Increasing the preheating temperature results into the blue shift of the absorption edges of the films. This can be explained by using the quantum-size effect. The photoluminescence spectra of the films show an UV emission at the near-band edge and a broad green-yellow emission at 470-620 nm. The former is closely related to the excitons, while the latter is to the intrinsic defect species in the film.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1191-1196
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model considering residual stiffness and stiffness discontinuity of bolted joints
Autorzy:
Wang, Sheng-Ao
Zhu, Min
Xu, Zi-Jian
Guo, Ming
Li, Biao
Wu, Fei
Powiązania:
https://bibliotekanauki.pl/articles/2087050.pdf
Data publikacji:
2022
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
nonlinear dynamic behaviour
Iwan model
energy dissipation
Opis:
The nonlinear dynamic behavior has an important impact on energy dissipation and vibra- tion damping characteristics of bolted joints. Firstly, the development of tangential dynamic models is summarized and analyzed. Secondly, a five-parameter Iwan model based on a trun- cated power-law distribution is proposed. The backbone and hysteresis curves are obtained. Thirdly, normalized and dimensionless analysis is performed. On the basis of the above, a more concise four-parameter Iwan model with stiffness continuity is proposed. Finally, the validity of the model is verified by comparing the energy dissipation vs excitation force amplitude curve with the experimental data.
Źródło:
Journal of Theoretical and Applied Mechanics; 2022, 60, 1; 63--75
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Understanding the difficult selective separation characteristics of high-ash fine coal
Autorzy:
Yang, Zili
Liu, Min
Chang, Guohui
Xia, Yangchao
Li, Ming
Xing, Yaowen
Gui, Xiahui
Powiązania:
https://bibliotekanauki.pl/articles/1845210.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
high-ash fine coal
flotation
rod grinding
floatability
slime coating
Opis:
As the supply of high-quality coals decreases and mechanical coal mining becomes more widespread, the high selective recovery of high-ash fine coal has become a prominent problem in the flotation process. Herein, we discuss the main reasons why the selective separation of high-ash fine coal is difficult. The analysis of high-ash fine coal properties shows that coarse particles (0.25-0.5 mm) account for 22.53% of the total size fraction and that 57.90% of the coal is moderate- or high-density (+1.4 g/cm3) intergrowth. Grinding experiments show that the traditional rod mill has little impact on the liberation of the intergrowth. Instead, its main function is to adjust the particle size composition to ensure that the particle sizes of high-ash fine coal are within the particle size range suitable for flotation. The flotation results show that a clean coal yield of 30.42%, with a 12.46% ash content, is obtained with the optimal flotation parameters through the roughing and cleaning flotation process. However, the flotation results also show that in the separation of high-ash fine coal, it is difficult to obtain clean coal with a high yield and low ash content at the same time. This is mainly due to the similar floatability of moderate-density and low-density coal particles, which allows a large number of moderate-density coal particles to be recovered, and a significant slime coating of clay on the coal’s surface that is generated during the flotation process. The results of this work provide valuable guidance for high-ash fine coal industrial flotation applications.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 5; 874-883
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An improved dynamic surface sliding mode method for autonomous cooperative formation control of underactuated USVS with complex marine environment disturbances
Autorzy:
Dong, Zaopeng
Qi, Shijie
Yu, Min
Zhang, Zhengqi
Zhang, Haisheng
Li, Jiakang
Liu, Yang
Powiązania:
https://bibliotekanauki.pl/articles/32909478.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
underactuated USV
dynamic surface sliding mode control
lateral velocity tracking differentiator
nonlinear disturbance observer
Opis:
In this paper, a novel dynamic surface sliding mode control (DSSMC) method, combined with a lateral velocity tracking differentiator (LVTD), is proposed for the cooperative formation control of underactuated unmanned surface vehicles (USVs) exposed to complex marine environment disturbances. Firstly, in view of the kinematic and dynamic models of USVs and the design idea of a virtual control law in a backstepping approach, the trajectory tracking control problem of USVs’ cooperative formation is transformed into a stabilisation problem of the virtual control law of longitudinal and lateral velocities. Then, aiming at the problem of differential explosion caused by repeated derivation in the process of backstepping design, the first-order low-pass filter about the virtual longitudinal velocity and intermediate state quantity of position is constructed to replace differential calculations during the design of the control law, respectively. In order to reduce the steady-state error when stabilising the virtual lateral velocity control law, the integral term is introduced into the design of the sliding mode surface with a lateral velocity error, and then the second-order sliding mode surface with an integral is structured. In addition, due to the problem of controller oscillation and the role of the tracking differentiator (TD) in active disturbance rejection control (ADRC), the LVTD is designed to smooth the state quantity of lateral velocity. Subsequently, based on the dynamic model of USV under complex marine environment disturbances, the nonlinear disturbance observer is designed to observe the disturbances and compensate the control law. Finally, the whole cooperative formation system is proved to be uniformly and ultimately bounded, according to the Lyapunov stability theory, and the stability and validity of the method is also verified by the simulation results.
Źródło:
Polish Maritime Research; 2022, 3; 47-60
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantification of lower extremity physical exposures in various combinations of sit/stand time duration associated with sit-stand workstation
Autorzy:
Pei, Huining
Yu, Suihuai
Babski-Reeves, Kari
Chu, Jianjie
Qu, Min
Tian, Baozhen
Li, Wenhua
Powiązania:
https://bibliotekanauki.pl/articles/2164098.pdf
Data publikacji:
2017-05-16
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
electromyography
ergonomic intervention
perceived level of discomfort
root mean square
body mass index
gender differences
Opis:
Background Sit-stand workstations are available for office work purposes but there is a dearth of quantitative evidence to state benefits for lower limb outcomes while using them. And there are no guidelines on what constitutes appropriate sit/stand time duration. The primary aim of this study has been to compare muscle activity and perceived discomfort in the lower extremity during various combinations of sit/stand time duration associated with a sit-stand workstation separately and to evaluate the effects of the sit-stand workstation on the lower extremity during the text entry task. Material and Methods During the 5 days, all participants completed a 2-h text entry task each day for various sit/stand time duration combinations as follows: 5/25 min, 10/20 min, 15/15 min, 20/10 min, 25/5 min. Lower extremity muscular exposure of 12 male and 13 female participants was collected at 8 sites by surface electromyography and body discomfort was calculated by a questionnaire under those 5 conditions. Results Results have demonstrated that lower extremity muscle activity has been significantly varied among the 5 sit/stand time duration groups. Perceived level of discomfort (PLD) has not differed significantly for 9 out of 10 body parts. Conclusions The muscle activity of the thigh region was influenced by sit/stand time duration significantly. Ergonomic exposures of lower extremity when using a sit-stand workstation were increased, particularly during the long time standing posture. Results indicate that body mass index (BMI) and gender were not significant factors in this study. Combination of sit/stand time duration 25/5 min appears to show positive effects on relief of muscle exposure of back of thigh in the shifts of sitting and standing work position. Med Pr 2017;68(3):315–327
Źródło:
Medycyna Pracy; 2017, 68, 3; 315-327
0465-5893
2353-1339
Pojawia się w:
Medycyna Pracy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two Gln187 mutants of human soluble APRIL inhibit proliferation of lung carcinoma A549 cells
Autorzy:
Dai, Shuangshuang
Zheng, Yingru
Chen, Bin
Gao, Min
Zhang, Yan
Zhang, Li
Gong, Wei
He, Fengtain
Powiązania:
https://bibliotekanauki.pl/articles/1040492.pdf
Data publikacji:
2009
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
APRIL
Gln187 mutant of sAPRIL
anti-tumor activity
Opis:
Soluble APRIL (sAPRIL), the active form of a proliferation-inducing ligand (APRIL), is implicated in the proliferation of tumor cells. Suppressing APRIL function has been considered as a potential strategy for the therapy of APRIL-associated tumors. In the present study, we generated human sAPRIL and its two mutants, Gln187-D-sAPRIL (Gln187 deleted) and Gly187-sAPRIL (Gln187 replaced by Gly). In vitro experiments showed that the two mutants had similar specific binding capacity to lung carcinoma A549 cells compared to the wild-type sAPRIL, and both, especially Gly187-sAPRIL, exhibited significant antagonistic effect on sAPRIL-induced tumor cell proliferation in a dose-dependent manner, which might be predominantly mediated by blocking sAPRIL-induced MEK and ERK phosphorylation but not p38MAPK or JNK signaling. In vivo experiments with nude mice bearing A549 cell-derived xenograft tumor showed that only the Gly187-sAPRIL mutant could significantly suppress the tumor growth. These results suggest that Gln187 may be a crucial amino acid in APRIL-mediated tumor cell proliferation via the MEK-ERK signaling pathway and that the sAPRIL mutants may serve as novel potential antagonists of APRIL for the therapy of APRIL-associated cancers.
Źródło:
Acta Biochimica Polonica; 2009, 56, 4; 703-710
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RFID tag group recognition based on motion blur estimation and YOLOv2 improved by Gaussian algorithm
Autorzy:
Li, Lin
Yu, Xiao-Lei
Liu, Zhen-Lu
Zhao, Zhi-Min
Zhang, Ke
Zhou, Shan-Hao
Powiązania:
https://bibliotekanauki.pl/articles/2051852.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
RFID
YOLOv2
neural network
GRNN
Opis:
Effective recognition of tags in the dynamic measurement system would significantly improve the reading performance of the tag group, but the blurred outline and appearance of tag images captured in motion seriously limit the effectiveness of the existing tag group recognition. Thus, this paper proposes passive tag group recognition in the dynamic environment based on motion blur estimation and improved YOLOv2. Firstly, blur angles are estimated with a Gabor filter, and blur lengths are estimated through nonlinear modelling of a Generalized Regression Neural Network (GRNN). Secondly, tag recognition based on YOLOv2 improved by a Gaussian algorithm is proposed. The features of the tag group are analyzed by the Gaussian algorithm, the region of interest of the dynamic tag is effectively framed, and the tag foreground is extracted; Secondly, the data set of tag groups are trained by the end-to-end YOLOv2 algorithm for secondary screening and recognition, and finally the specific locations of tags are framed to meet the effective identification of tag groups in different scenes. A considerable number of experiments illustrate that the fusion algorithm can significantly improve recognition accuracy. Combined with the reading distance, the research presented in this paper can more accurately optimize the three-dimensional structure of the tag group, improve the reading performance of the tag group, and avoid the interference and collision of tags in the communication channel. Compared with the previous template matching algorithm, the tag group recognition ability put forward in this paper is improved by at least 13.9%, and its reading performance is improved by at least 6.2% as shown in many experiments.
Źródło:
Metrology and Measurement Systems; 2022, 29, 1; 53-74
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Communication atmosphere in humans and robots interaction based on the concept of fuzzy atmosfield generated by emotional states of humans and robots
Autorzy:
Liu, Z. T.
Chen, L. F.
Dong, F. Y.
Hirota, K.
Min, W.
Li, D. Y.
Yamazaki, Y.
Powiązania:
https://bibliotekanauki.pl/articles/384920.pdf
Data publikacji:
2013
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
human-robot interaction
communication atmosphere
fuzzy logic
emotion recognition
Opis:
Communication atmosphere based on emotional states of humans and robots is modeled by using Fuzzy Atmosfield (FA), where the human emotion is estimated from bimodal communication cues (i.e., speech and gesture) using weighted fusion and fuzzy logic, and the robot emotion is generated by emotional expression synthesis. It makes possible to quantitatively express overall affective expression of individuals, and helps to facilitate smooth communication in humans-robots interaction. Experiments in a household environment are performed by four humans and five eye robots, where emotion recognition of humans based on bimodal cues achieves 84% accuracy in average, improved by about 10% compared to that using only speech. Experimental results from the model of communication atmosphere based on the FA are evaluated by comparing with questionnaire surveys, from which the maximum error of 0.25 and the minimum correlation coefficient of 0.72 for three axes in the FA confirm the validity of the proposal. In ongoing work, an atmosphere representation system is being planned for casual communication between humans and robots, taking into account multiple emotional modalities such as speech, gesture, and music.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2013, 7, 2; 52-63
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation of chromosome damage and promoter methylation status of the DNA repair genes MGMT and hMLH1 in Chinese vinyl chloride monomer (VCM)-exposed workers
Autorzy:
Wu, Fen
Liu, Jing
Qiu, Yu-Lan
Wang, Wei
Zhu, Shou-Min
Sun, Pin
Miao, Wen-Bin
Li, Yong-Liang
Brandt-Rauf, Paul W.
Xia, Zhao-Lin
Powiązania:
https://bibliotekanauki.pl/articles/2179802.pdf
Data publikacji:
2013-03-01
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
vinyl chloride monomer
chromosome damage
MGMT
hMLH1
DNA methylation
Opis:
Objective: To explore the association of the methylation status of MGMT and hMLH1 with chromosome damage induced by vinyl chloride monomer (VCM). Materials and Methods: Methylation of MGMT and hMLH1 was measured in 101 VCM-exposed workers by methylation-specifi c PCR. Chromosome damage in peripheral blood lymphocytes was measured by the cytokinesis-block micronucleus assay. The subjects were divided into chromosome damaged and non-damaged groups based on the normal reference value of micronuclei frequencies determined for two control groups. Results: MGMT promoter methylation was detectable in 5 out of 49 chromosome damaged subjects, but not in the chromosome non-damaged subjects; there was a signifi cant difference in MGMT methylation between the two groups (p < 0.05). Conclusions: We detected aberrant promoter methylation of MGMT in a small number of chromosome damaged VCM-exposed workers, but not in the chromosome non-damaged subjects. This preliminary observation warrants further investigation in a larger study.
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2013, 26, 1; 173-182
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Genomics and the evolution of aminoacyl-tRNA synthesis.
Autorzy:
Ruan, Benfang
Ahel, Ivan
Ambrogelly, Alex
Becker, Hubert
Bunjun, Shipra
Feng, Liang
Tumbula-Hansen, Debra
Ibba, Michael
Korencic, Dragana
Kobayashi, Hiroyuki
Jacquin-Becker, Clarisse
Mejlhede, Nina
Min, Bokkee
Raczniak, Gregory
Rinehart, Jesse
Stathopoulos, Constantinos
Li, Tong
Söll, Dieter
Powiązania:
https://bibliotekanauki.pl/articles/1044116.pdf
Data publikacji:
2001
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
evolution
tRNA
aminoacyl-tRNA
translation
protein synthesis
Opis:
Translation is the process by which ribosomes direct protein synthesis using the genetic information contained in messenger RNA (mRNA). Transfer RNAs (tRNAs) are charged with an amino acid and brought to the ribosome, where they are paired with the corresponding trinucleotide codon in mRNA. The amino acid is attached to the nascent polypeptide and the ribosome moves on to the next codon. Thus, the sequential pairing of codons in mRNA with tRNA anticodons determines the order of amino acids in a protein. It is therefore imperative for accurate translation that tRNAs are only coupled to amino acids corresponding to the RNA anticodon. This is mostly, but not exclusively, achieved by the direct attachment of the appropriate amino acid to the 3'-end of the corresponding tRNA by the aminoacyl-tRNA synthetases. To ensure the accurate translation of genetic information, the aminoacyl-tRNA synthetases must display an extremely high level of substrate specificity. Despite this highly conserved function, recent studies arising from the analysis of whole genomes have shown a significant degree of evolutionary diversity in aminoacyl-tRNA synthesis. For example, non-canonical routes have been identified for the synthesis of Asn-tRNA, Cys-tRNA, Gln-tRNA and Lys-tRNA. Characterization of non-canonical aminoacyl-tRNA synthesis has revealed an unexpected level of evolutionary divergence and has also provided new insights into the possible precursors of contemporary aminoacyl-tRNA synthetases.
Źródło:
Acta Biochimica Polonica; 2001, 48, 2; 313-321
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
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