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Wyświetlanie 1-15 z 23
Tytuł:
Off-Axis Electron Holography of Magnetic Nanostructures: Magnetic Behavior of Mn Rich Nanoprecipitates in (Mn,Ga)As System
Autorzy:
Barańska, M.
Dłużewski, P.
Kret, S.
Morawiec, K.
Li, Tian
Sadowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1033003.pdf
Data publikacji:
2017-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.jp
68.37.Lp
07.05.Pj
75.50.Pp
Opis:
The Lorentz off-axis electron holography technique is applied to study the magnetic nature of Mn rich nanoprecipitates in (Mn,Ga)As system. The effectiveness of this technique is demonstrated in detection of the magnetic field even for small nanocrystals having an average size down to 20 nm.
Źródło:
Acta Physica Polonica A; 2017, 131, 5; 1406-1408
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of Gaussian Schell-model vortex beams in biological tissues
Autorzy:
Duan, Meiling
Tian, Yannan
Li, Jinhong
Powiązania:
https://bibliotekanauki.pl/articles/173473.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
GSM vortex beams
intensity distribution
spectral degree of coherence
biological tissue
Opis:
The dependence of changes in the relative intensity and the spectral degree of coherence on the refractive-index Cn2 of biological tissues, space correlation length σ0 and wavelength λ of the Gaussian Schell-model (GSM) vortex and non-vortex beams in biological tissues has been studied. It is shown that the intensity distribution of GSM vortex beams passing through the biological tissues undergoes several stages. The bigger Cn2 is, and the smaller σ0 is, the quicker the intensity evolution is. The attenuation of intensity for GSM vortex beams is much slower than that of non-vortex beams, thus the beam quality of the former is better than the latter. When propagating through the biological tissue, the phase singularities of GSM vortex beams will appear. As the propagation distance increases, the position of the phase singularities will shift, and these points will disappear where the changes in the spectral degree of coherence of GSM vortex beams are consistent with those of GSM non-vortex beams. At the same propagation distance, the bigger Cn2 is, and the smaller σ0 and λ are, the shorter the distance between the phase singularities and the z axis is, when the propagation distance z is in the range of 0–50 μm.
Źródło:
Optica Applicata; 2019, 49, 2; 203-215
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stirred-tank leaching of coarse-grained waste, printed circuit boards with Acidithiobacillus ferrooxidans
Autorzy:
Fu, Kaibin
Tian, Li
Hou, Puyao
Long, Meiqiao
Chen, Shu
Lin, Hai
Powiązania:
https://bibliotekanauki.pl/articles/2146844.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
stirred tank leaching
coarse-grained WPCBs
A ferrooxidans
H+ consumption
Avrami equation
Opis:
Stirred tank leaching of metals from coarse-grained waste, printed circuit boards (WPCB) used Acidithiobacillus ferrooxidans (A. ferrooxidans) at ambient temperature (20-35°C). The effect of the baffle size, WPCB concentration, and inoculation volume was tested. 95.92% of Cu, 93.53% of Al, 92.58% of Zn, 65.27% of Ni, and 95.33% of Sn in WPCBs were leached under the optimal conditions: no baffle, WPCB concentration of 5.0% (w/w), and inoculation volume of 5% (v/v). The alkaline substance and reactivity metal of WPCBs, and the oxidation of Fe2+, consume H+. Adding acid can maintain the pH value of the leaching solution, which is conducive to the growth and reproduction of the bacteria and improves the leaching efficiency of WPCBs. The second-order dynamics model can describe the acid consumption in the bioleaching process of coarse-grained WPCBs. Moreover, the Avrami equation can successfully explain the bioleaching kinetics of Cu, Al, Zn, Ni, and Sn from the coarse-grained WPCBs. The key factors controlling the bioleaching of coarse-grained WPCBs are metal reactivity and specific surface area. These results revealed that bioleaching metals from coarse-grained WPCBs using A.ferrooxidans is feasible, and has important significance to guiding its industrialization.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 5; 153--163
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Probe Measurements of Electron Transport in GaN:Si/(Ga,Mn)N/GaN:Si Spin Filter Structures
Autorzy:
Kalbarczyk, K.
Foltyn, M.
Grzybowski, M.
Stefanowicz, W.
Adhikari, R.
Li, Tian
Kruszka, R.
Kamińska, E.
Piotrowska, A.
Bonanni, A.
Dietl, T.
Sawicki, M.
Powiązania:
https://bibliotekanauki.pl/articles/1398574.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.25.Dc
73.40.Cg
73.43.Qt
78.55.Cr
Opis:
Results of two-probe magnetoresistance studies in GaN:Si/(Ga,Mn)N/GaN:Si prospective spin filter structures are reported. It is postulated that transport characteristics are strongly influenced by highly conductive threading dislocations and that shrinking of the device size partially mitigates the issue. Simultaneously, maxima at ≈1500 Oe on overall weak, up to 2%, negative magnetoresistance are seen at low temperature, whose origin has been tentatively assigned to effects taking place at the contacts areas.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1196-1198
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flotation separation of rutile from almandine using octadecyl amine polyoxyethylene ether as collector
Autorzy:
Li, Hongqiang
Zheng, Huifang
Chen, Qian
Kasomo, Richard M.
Leng, Jiahao
Weng, Xiaoqing
Song, Shaoxian
Xiao, Linbo
Tian, Chengtao
Powiązania:
https://bibliotekanauki.pl/articles/1449410.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
rutile
almandine
flotation separation
adsorption mechanism
Opis:
In this study, the flotation separation of rutile from almandine using cationic surfactant Octadecyl amine polyoxyethylene ether (AC1815) as a new collector was investigated. The adsorption mechanism of AC1815 on rutile was illustrated through zeta potential measurement, infrared spectrum and XPS analyses. The flotation experiments demonstrated that AC1815 exhibited an excellent collecting ability and selectivity for rutile. The results of zeta potential measurements and XPS analysis indicated that more AC1815 was adsorbed on rutile surface instead of almandine. The adsorption mechanism of AC1815on rutile was mainly attributed to the electrostatic interaction between the positively charged molecules of AC1815 and the negatively charged rutile surface, and the hydrogen bonding between the protonated $≡NH^+$, $≡N$ group of AC1815 and $Ti-OH$ on rutile surface.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 4; 653-664
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault mode analysis and reliability optimization design of a mechanical interface based on cylindrical cam mechanisms
Autorzy:
Li, Jian-Hao
Liu, Zhi-Jie
Wang, Da-Peng
Tian, Yun
Zhao, Yu-Chong
Powiązania:
https://bibliotekanauki.pl/articles/1841922.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
mechanical interface
fault mode analysis
Monte Carlo simulation
reliability design
cylindrical cam mechanism
Opis:
The mechanical interface has the characteristics of low shock and vibration, and is emphasized in the aerospace and ocean engineering fields. In this paper, a mechanical interface based on coupled cylindrical cam mechanisms is designed. It can achieve the expected functions, but there exist faults in some times. The fault modes and causes of the interface are firstly analyzed. Then a design approach based on Monte Carlo simulation is presented for analyzing and optimizing its reliability. According to the fault modes, the performance functions of the interface are established for obtaining the optimal scheme. A case is given to illustrate the proposed method. The simulation results and the prototype experiments prove that the optimization scheme effectively improves the reliability of the interface, and has better performance than the original one.
Źródło:
Eksploatacja i Niezawodność; 2020, 22, 4; 715-723
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a rapid immunochromatographic assay for detection of antibodies against porcine epidemic diarrhea virus
Autorzy:
Li, R.
Ma, J.
Tian, X.
Yu, Y.
Qiao, S.
Wang, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2087760.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porcine epidemic diarrhea virus
immunochromatographic test strip
nucleocapsid protein
diagnosis
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 1; 139-147
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Isolation and genetic analysis of a variant porcine epidemic diarrhea virus in China
Autorzy:
Li, R.-f.
Tian, X.-g.
Liu, Y.
Xu, J.
Liu, D.-y.
Powiązania:
https://bibliotekanauki.pl/articles/30492.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
Porcine epidemic diarrhea virus (PEDV) is having a severe effect on the pig breeding industry in central China. The mucosa and the content of the small intestine from newborn pre-weaned piglets with diarrhea were tested for the presence of PEDV by molecular and morphologic methods, and found to be positive. Negative-staining electron microscopy (EM) revealed the presence of coronavirus- like particles in the samples. The result of molecular detection by nested RT-PCR based on the amplification of the M gene was positive. Using a novel alternative method we successfully propagated the PEDV strain (CH/QX-2) in Vero cells, confirmed by ultrathin sections of the cells and Immunofluorescence assay (IFA). Phylogenetic analysis based on the partial S gene showed that the CH/QX-2 isolate was genetically closer to strains more commonly found in China, but differed genetically from two domestic strains (CH/S, 1986 and LZC, 2007), Korean strains (DR13, 2007), and the vaccine strain (CV777 vs) currently being used in China. CH/QX-2 formed a unique clade in the derived phylogenetic tree indicating that the CH/QX-2 strain currently circulating in central China is a new variant of PEDV. This study extends current knowledge on the diversity and epidemiology of PEDV.
Źródło:
Polish Journal of Veterinary Sciences; 2016, 19, 1
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active fault tolerance control of a wind turbine system using an unknown input observer with an actuator fault
Autorzy:
Li, S.
Wang, H.
Aitouche, A.
Tian, Y.
Christov, N.
Powiązania:
https://bibliotekanauki.pl/articles/329822.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
wind turbine system
linear parameter varying system
fault tolerant control
unknown input observer
elektrownia wiatrowa
sterowanie tolerujące uszkodzenia
obserwator wejściowy
Opis:
This paper proposes a fault tolerant control scheme based on an unknown input observer for a wind turbine system subject to an actuator fault and disturbance. Firstly, an unknown input observer for state estimation and fault detection using a linear parameter varying model is developed. By solving linear matrix inequalities (LMIs) and linear matrix equalities (LMEs), the gains of the unknown input observer are obtained. The convergence of the unknown input observer is also analysed with Lyapunov theory. Secondly, using fault estimation, an active fault tolerant controller is applied to a wind turbine system. Finally, a simulation of a wind turbine benchmark with an actuator fault is tested for the proposed method. The simulation results indicate that the proposed FTC scheme is efficient.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2018, 28, 1; 69-81
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of direct reduction time of vanadium titanomagnetite concentrate on the preparation and photocatalytic performance of calcium titanate
Autorzy:
Li, Xiaohui
Kou, Jue
Sun, Tichang
Wu, Shichao
Tian, Yuechao
Powiązania:
https://bibliotekanauki.pl/articles/1449028.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
vanadium titanomagnetite concentrate
calcium titanate
direction reduction
metallic iron
photocatalytic performance
Opis:
Effects of direct reduction time of vanadium titanomagnetite concentrate (VTCE) on the preparation and photocatalytic performance of calcium titanate were investigated in this study. It was found that extending the reduction time could not only promote the formation of calcium titanate, but also facilitate the reduction of iron minerals in the reduction products. The optimum reduction time was 180min under the conditions of $CaCO_3$ dosage of 18wt%, reduction temperature of 1400℃ and lignite dosage of 70wt%. The reduced iron (Fe grade of 90.95wt%, Fe recovery of 92.21wt%) and calcium titanate were obtained via grinding-magnetic separation. Moreover, calcium titanate prepared via the direct reduction method could be used as a photocatalyst, where the degradation degree of methylene blue increased from 25.13% to 60.14% with the addition of calcium titanate. Furthermore, Langmuir Hinshelwood fitting results indicated that the degradation of methylene blue by the calcium titanate prepared under different reduction times conformed to first-order reaction kinetics, where the photocatalytic degradation rate of methylene blue was noted to be the highest for a reduction time of 180 min.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 75-86
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sp100 interacts with phage ΦC31 integrase to inhibit its recombination activity
Autorzy:
Lin, Yun
Li, Zhi-Hui
Wang, Jing-Jing
Xu, Gua-Lan
Shen, Qi
Tian, Lin
Xue, Jin-Lun
Chen, Jin-Zhong
Powiązania:
https://bibliotekanauki.pl/articles/1039951.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Sp100
ΦC31 integrase
recombination
Opis:
Phage ΦC31 integrase is a potential vector for the insertion of therapeutic genes into specific sites in the human genome. To understand the mechanism involved in ΦC31 integrase-mediated recombination, it is important to understand the interaction between the integrase and cellular proteins. Using a yeast two-hybrid system with pLexA-ΦC31 integrase as bait, we screened a pB42AD human fetal brain cDNA library for potential interacting cellular proteins. From the 106 independent clones that were screened, 11 potential interacting clones were isolated, of which one encoded C-terminal fragment of Sp100. The interaction between Sp100 and ΦC31 integrase was further confirmed by yeast mating and co-immunoprecipitation assays. The hybridization between a ΦC31 integrase peptide array and an HEK293 cell extract revealed that residues 81RILN84 in the N-terminus of ΦC31 integrase are responsible for the interaction with Sp100. Knocking down endogenous Sp100 with Sp100-specific siRNA increased ΦC31 integrase-mediated recombination but did not impact reporter gene expression. Therefore, endogenous Sp100 may interact with ΦC31 integrase and inhibit the efficiency of ΦC31 integrase-mediated recombination.
Źródło:
Acta Biochimica Polonica; 2011, 58, 1; 67-73
0001-527X
Pojawia się w:
Acta Biochimica Polonica
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:
Double-image encryption algorithm based on discrete fractional angular transform and fractional Fourier transform
Autorzy:
Qiu, Tian
Dai, Wei-Hua
Chen, Su-Hua
Zhou, Hang
Gong, Li-Hua
Powiązania:
https://bibliotekanauki.pl/articles/2172857.pdf
Data publikacji:
2022
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
chaotic system
fractional transform
discrete fractional angular transform
double-image encryption
Opis:
By combining fractional Fourier transform with discrete fractional angular transform, a double-image encryption algorithm is designed. The discrete cosine transform is performed on two grayscale images to generate a spectrum image, and then the generated spectrum image is compressed into an image with Zigzag scanning. The compressed image is processed with the discrete fractional angular transform, and then fractional Fourier transform and double random phase coding are executed on the image. The DNA operation controlled by chaotic system is introduced to change the pixel values. Finally, the ciphertext image is obtained through bit-level permutation and pixel adaptive diffusion. The statistical information of the plaintext images is employed as the input of the SHA-256 to calculate the initial conditions of the chaotic map. Simulation experiments demonstrate that the double-image encryption algorithm can effectively reduce the correlation among adjacent pixels of the plaintext images.
Źródło:
Optica Applicata; 2022, 52, 4; 669--684
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lipopolysaccharide accelerates fine particulate matter-induced cell apoptosis in human lung bronchial epithelial cells
Autorzy:
Ru, Qin
Xiong, Qi
Chen, Lin
Tian, Xiang
Yue, Kai
Ma, Baomiao
Liu, Lu
Wu, Rihui
Xu, Congyue
Pi, Mingshan
Li, Chaoying
Powiązania:
https://bibliotekanauki.pl/articles/2161782.pdf
Data publikacji:
2017-11-03
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
Apoptosis
cytotoxicity
inflammation
fine particulate matter
free radicals
bronchial epithelial cells
Opis:
Objectives The aim of the study has been to investigate the effect of the Standard Reference Material of fine particulate matter (SRM 2786) on cytotoxicity and apoptosis in human lung bronchial epithelial cells (16HBE cells). Whether the lipopolysaccharide (LPS)-induced inflammation could further accelerate cell apoptosis induced by SRM 2786 stimulation has also been determined. Material and Methods 16HBE cells were exposed to various doses of SRM 2786 with or without LPS. The following parameters: cytotoxicity, apoptotic rate, Bax/Bcl-2 expression, nitric oxide (NO) production, and reactive oxygen species (ROS) generation were measured. Results The results have shown that SRM 2786 induces cell damage and apoptosis of 16HBE cells as demonstrated by significant decrease in expression of Bcl-2 and increase in expression of Bax. When compared with the control cells, the apoptotic rate of cells treated by 500 μg/ml of SRM 2786 increased from 2.43±0.21% to 43.96±2.95% (p < 0.01). Further, there was an elevated production of NO and ROS post SRM 2786 treatment. The level of NO in cells treated with 500 μg/ml of SRM 2786 was 18.33±1.02 μmol/l whereas that of control cells was 1.58±0.31 μmol/l (p < 0.01). When compared with the control group, the level of intracellular ROS increased by 24% after treatment with 500 μg/ml of SRM 2786 (p < 0.05). In addition, LPS pre-treatment may accelerate cell apoptosis by increasing generation of NO and ROS followed by SRM 2786 stimulation. When compared to cells treated with 125 μg/ml of SRM 2786 alone, the levels of NO and ROS in cells pretreated with LPS increased by 28% and 11.6%, respectively (p < 0.05), and the apoptotic rate increased from 34.62±4.44% to 54.11±3.34% (p < 0.01). Conclusions These findings have suggested that in vitro exposure to SRM 2786 could induce 16HBE cells apoptosis probably by means of the mechanism involving the generation of free radicals, while the degree of apoptosis would be further aggravated under inflammation condition. Int J Occup Med Environ Health 2018;31(2):173–183
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2018, 31, 2; 173-183
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shoulder girdle muscle activity and fatigue during automobile chassis repair
Autorzy:
Tian, Baozhen
Yu, Suihuai
Chu, Jianjie
Li, Wenhua
Powiązania:
https://bibliotekanauki.pl/articles/2161964.pdf
Data publikacji:
2019-07-15
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
muscle activity
surface electromyography
muscle fatigue
perceived level of discomfort
automobile chassis repair
shoulder postures
Opis:
Objectives The objective of this study was to assess the postures that were commonly used in automobile chassis repair operations, and to evaluate shoulder girdle muscle fatigue for different combinations of the weight of hand-tools. Material and Methods Two right muscles, including upper trapezius (UT) and middle deltoid (MD), were selected. Surface electromyography (SEMG) and a perceived level of discomfort (PLD) were used to assess the degree of shoulder girdle fatigue. Fifteen healthy young male subjects from the Northwestern Polytechnical University participated in the test. The test consisted of assuming 4 different postures and maintaining each of them for 60 s. The 4 postures varied in terms of dumbbell weights, standing for the hand-tools weight: W1 was 0.48 kg and W2 was 0.75 kg; the 4 shoulder postures were shoulder flexions of 150°, 120°, 90°, and 60°, combined with an included elbow angle of 180°, 150°, 120° and 90°, respectively. The experimental sequences were randomly selected. The signals of SEMG and the values of PLD in the shoulder girdle were recorded in 60 s. All subjects completed the whole test. The repeated measure analysis of variance (ANOVA) was performed to ascertain differences between dumbbell weight (0.48 kg and 0.75 kg) and shoulder postures (150°/180°, 120°/150°, 90°/120° and 60°/90°). The Friedman test was utilized to determine the significant differences for UT(PLD) and MD(PLD) on shoulder postures. Spearman’s correlation was used to analyze the relationship between the subjective and objective measurements. Results Significant correlational relationships existed between the UT percentage of the maximal voluntary electrical activation (%MVE) and UT(PLD) (r = 0.459, p < 0.01), between MD(%MVE) and MD(PLD) (r = 0.821, p < 0.01). The results showed that SEMG and PLD of the 4 postures under analysis differed significantly (p < 0.05). Conclusions It was indicated that posture T4 (shoulder forward flexion 60° and included elbow angle 90°) resulted in the lowest fatigue, both in terms of the objective measure and the subjective perception, which meant that this posture was more ergonomic. Int J Occup Med Environ Health. 2019;32(4):537–52
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2019, 32, 4; 537-552
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
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