http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Yanqiu Chen,Jin Zhang,Peishi Yu,Jian Wu,Weibo Wang,Junhua Zhao 한국강구조학회 2020 International Journal of Steel Structures Vol.20 No.4
The stress and strain concentration in some component has been a signifi cant topic for structural safety assessment. However, the evaluation of the stress and strain concentration based on the widely existing solutions for linear elastic material under static loading would lead to remarkable errors when the material undergoes the dynamic loading, since the coupling eff ect induced by the nonlinearity of the stress–strain relationship and the strain-rate strengthening could be of signifi cant infl uence. Here we analyzed the strain-rate dependent concentration of stress and strain for a visco-plastic plate with an elliptic hole subjected to dynamic loading. The three-dimensional stress and strain are calculated by fi nite element analyses based on a rate-dependent Johnson–Cook model in which the material constants are set according to a typical visco-plastic standard 45 carbon steel. Our results show that both the plastic stress and strain concentration factors signifi cantly depend on not only the strain but also the strain rate. With the increment of the remote strain rate, the stress concentration monotonically increases, while the strain concentration shows decreasing tendency.
Yanqiu Zhao,Xiaohong Zhan,Qiyu Gao,Shuai Chen,Yue Kang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.3
Laser-metal inter gas (MIG) hybrid welding technique provides higher overall productivity over the traditional fusionwelding processes for joining medium-thick aluminum alloy. In this paper, laser-MIG hybrid welding experiment was performedby the TruDisk 12003 Laser and KUKA robot. The second fusion line, the laser-dominated region and laser-MIGhybrid-dominated region were introduced to this study to discuss the microstructure distribution. A three-dimensionalfinite element model was established by MSC. Marc to study the thermal field distribution of laser-MIG hybrid weldingprocess. It found that the temperature in the laser-MIG hybrid-dominated region was much higher than the laser-dominatedregion. The formation of the second fusion line in the welded joint is mainly owing to the different heat effect of laser-archybrid-dominated region and laser-dominated region. The crystalline size of equiaxed dendrite grains in the laser-MIGhybrid-dominated region is finer than the laser-dominated region. In addition, the tensile property was measured to dissectthe failure mechanism of the laser-MIG hybrid welding joints. The element content in fractured surface at the position ofdimple and pore wall were comprehensively analyzed. The element content of Mg and O in pore wall are higher than dimple. In the solidification process, the growth of equiaxed dendrite grains is in part hindered by the existence of coarse pores inthe laser-MIG hybrid-dominated region.
Yanqiu Wang,Ying Zhao,Ling Liu,Yan Chen,Dong Ai,Yingshui Yao,Yuelong Jin 대한신경정신의학회 2020 PSYCHIATRY INVESTIGATION Vol.17 No.3
Objective The purpose of this cross-sectional survey is to explore the current state of Internet addiction (IA) in Chinese medical students and its connection with medical students’ sleep quality and self-injury behavior. Methods Respondents were came from Wannan Medical College, China. The Young’s Internet Addiction Test, Pittsburgh Sleep Quality Index (PSQI), Self-Harm Questionnaire were used in this cross-sectional survey. A total of 3,738 medical students were investigated, 1,552 (41.52%) males, 2,186 (58.48%) females. T-test, chi-square test and MANOVA were used for data analysis. Results Of the 3,738 medical students, 1,054 (28.2%) reported having IA, 1,126 (30.1%) reported having poor sleep quality, 563 (15.1%) having self-harm behaviors. IA tends to be more female, upper grade students. The sleep quality of IA was worse than that of non-IA (χ2=54.882, p<0.001), and the possibility of self-injury was higher than non-IA (χ2=107.990, p<0.001). Conclusion This survey shows that the IA detection rate of medical students was 28.2%. Females, higher grade students had a higher IA detection rate. The low sleep quality and self-injury behavior of medical students are associated with IA.
Yanqiu Wei,Baozhi Yang,Yunlong Li,Yongcheng Duan,Deyu Tian,Baoxiang He,Chuangfu Chen,Wenjun Liu,Limin Yang 대한수의학회 2020 Journal of Veterinary Science Vol.21 No.4
A fluorescent microsphere-based immunochromatographic strip test (FICT) was developed for the rapid, sensitive, and quantitative detection of porcine reproductive and respiratory syndrome virus (PRRSV) antibodies at the pen-side. The assay was based on the formation of a sandwich immune-complex (anti-pig IgG-PRRSV antibodies-NSP7/N), which was validated by a comparison with IDEXX-ELISA using 3325 clinical specimens. The diagnostic specificity, sensitivity, and accuracy of FICT were 97.28, 93.41, and 94.95%, respectively. FICT showed a good correlation with the virus neutralization assay. Overall, a promising pen-side diagnostic tool was developed for the rapid and quantitative detection of PRRSV antibodies within 15 min.
Chen, Wuguo,Zhang, Jiamin,Dong, Changjin,Yang, Bo,Li, Yanqiu,Liu, Chuanfeng,Hu, Yuanyang Korean Society for Biochemistry and Molecular Biol 2006 Journal of biochemistry and molecular biology Vol.39 No.4
We examined the intracellular localization of NS5 protein of Dendrolimus punctatus cytoplasmic polyhedrosis virus (DpCPV) by expressing NS5-GFP fusion protein and proteins from deletion mutants of NS5 in baculovirus recombinant infected insect Spodoptera frugiperda (Sf-9) cells. It was found that the NS5 protein was present at the plasma membrane of the cells, and that the N-terminal portion of the protein played a key role in the localization. A transmembrane region was identified to be present in the N-terminal portion of the protein, and the detailed transmembrane domain (SQIHMVWVKSGLVFF, 57-71aa) of N-terminal portion of NS5 was further determined, which was accorded with the predicted results, these findings suggested that NS5 might have an important function in viral life cycle.
Shuai Chen,Xiaohong Zhan,Yanqiu Zhao,Youfa Wu,Dongtao Liu 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.6
Dual laser-beam bilateral synchronous welding is introduced to produce the 2.5 mm thick 5A90 Al–Li alloy T-joint. Thegrain morphology and grain size of weld metal (WM) in the T-joint are analyzed and calculated. The tensile experiment,scanning electron microscopy and energy disperse spectroscopy are respectively employed to study the tensile strength,fracture morphology and chemical composition of the T-joint. The results reveal that when the laser power is increased from2500 to 3000 W, the grain sizes of fine-grained layers and columnar dendrites near the fusion line are significantly reduced. Conversely, that of equiaxed dendrites at the WM center is not sensitive to the variety of laser power. Moreover, the degreeof elemental segregation in WM near the fusion line is also aggravated with the increasing of the laser power. The tensilestrength of the T-joint with the laser power of 2500 W is significantly higher than that with the laser power of 3000 W. Thetensile fracture locations are occurred in the weld toe with obvious pores, shear dimples and tear ridges, which are the typicalcharacteristics of ductile fracture. Besides, the chemical compositions of the second phase particles in the WM are moresensitive to than the variation of laser power compared with that of the matrix.
Juan Zhang,Yanqiu Cai,Guocheng Du,Jian Chen,Miao Wang,Zhen Kang 한국미생물학회 2017 The journal of microbiology Vol.55 No.7
Cutinase as a promising biocatalyst has been intensively studied and applied in processes targeted for industrial scale. In this work, the cutinase gene tfu from Thermobifida fusca was artificially synthesized according to codon usage bias of Saccharomyces cerevisiae and investigated in Saccharomyces cerevisiae. Using the α-factor signal peptide, the T. fusca cutinase was successfully overexpressed and secreted with the GAL1 expression system. To increase the cutinase level and overcome some of the drawbacks of induction, four different strong promoters (ADH1, HXT1, TEF1, and TDH3) were comparatively evaluated for cutinase production. By comparison, promoter TEF1 exhibited an outstanding property and significantly increased the expression level. By fed-batch fermentation with a constant feeding approach, the activity of cutinase was increased to 29.7 U/ml. The result will contribute to apply constitutive promoter TEF1 as a tool for targeted cutinase production in S. cerevisiae cell factory.
Regional heterogeneity of agricultural carbon emission reduction potential in China
Shiqi Hou,Mingjie Chen,Sijie Tao,Peijia Li,Yanqiu He 대한환경공학회 2024 Environmental Engineering Research Vol.29 No.4
Agriculture, a critical industry highly susceptible to climate change, requires thorough analysis of its carbon reduction potential and priority exploration to advance towards green and sustainable development. Therefore, this study employs a variable coefficient panel model to examine the regional heterogeneity of influencing factors. It also uses a PSO-BP neural network model to simulate changes in Chinas agricultural carbon intensity and total emissions under three distinct scenarios. The findings revealed that (1) under the baseline scenario and aggressive scenario, most Chinese provinces and cities can achieve a 30% reduction in agricultural carbon intensity by 2030, and the advanced economic development in the eastern coastal regions positions them favorably for achieving peak carbon emissions. (2) Economic interventions are the main driving force for most Chinese provinces and cities to achieve their agricultural carbon intensity reduction targets, followed by technological interventions and agricultural population adjustment. (3) Eight provinces and cities can be used as emission reduction benchmarks, while Xinjiang, Inner Mongolia, and Henan are challenging points in attaining national emission reduction targets.
Optical temperature sensing properties of Yb3+/Tm3+ co-doped NaLuF4 crystals
Lili Tong,Xiangping Li,Ruinian Hua,Lihong Cheng,Jiashi Sun,Jinsu Zhang,Sai Xu,Hui Zheng,Yanqiu Zhang,Baojiu Chen 한국물리학회 2017 Current Applied Physics Vol.17 No.7
Yb3þ/Tm3þ and Yb3þ/Er3þ co-doped NaLuF4 crystals were synthesized by a facile hydrothermal method. The optical temperature sensing properties of Tm3þ based upon its two thermally coupled energy levels 3F2, 3 and 3H4 were systematically investigated by means of fluorescence intensity ratio (FIR) technique. The 980 nm laser-induced thermal effect on Tm3þ doped NaLuF4 crystals was studied by using Er3þ doped sample as thermal probe. The temperature sensitivity of Tm3þ in NaLuF4: Yb3þ/Tm3þ crystals shows a nonlinear dependence on temperature, and the maximum value is about 0.00045 K『1 at 600 K. The accuracy and reliability of the optical thermometry based on Tm3þ in NaLuF4: Yb3þ/Tm3þ crystals has been checked by using Yb3þ/Er3þ co-doped sample as temperature sensing unit. The results demonstrate that NaLuF4: Yb3þ/Tm3þ crystals have good sensing stability and may have potential application for the optical thermometry.