Dislocation Density-Based Constitutive Model and Processing Map for T2 Copper During Isothermal and Time-Variant Deformation

Gang Chen,Yu Jin,Jing Wang,Cheng Zhang,Qiang Chen,Hongming Zhang,Xingjian Zhao,Zhiyong Li,Changhai Xie,Zhiming Du 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.9

Isothermal compression tests were carried out to study the hot deformation behavior of T2 copper under various conditions. The deformation parameters, such as temperature and strain rate, have strong influence on flow stress and microstructureevolution of the alloy. A unified dislocation density-based model considering dynamic recovery and recrystallization wasestablished. And material parameters of the developed model were optimized by genetic algorithm. Comparisons betweenthe experimental and model data demonstrates that the developed model can precisely describe the flow behavior at quitewide range of deformation conditions. Meanwhile, the designed iterative procedure allows the model to be applied in timevariantdeformation conditions. Processing map and microstructure examination were constructed to optimize the processingwindow of the studied alloy. According to the processing maps, flow instability mainly appeared at low temperatures of500–650 °C and strain rates higher than 0.1 s−1. The optimum deformation parameters of T2 copper was concluded as thetemperature range of 700–800 °C and the strain rate of 0.1–1 s−1.

Effect of oxidizing treatment on electrocatalytic activity of boron‑doped amorphous carbon thin films

Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

p‐Type InP Nanopillar Photocathodes for Efficient Solar‐Driven Hydrogen Production

Lee, Min Hyung,Takei, Kuniharu,Zhang, Junjun,Kapadia, Rehan,Zheng, Maxwell,Chen, Yu‐,Ze,Nah, Junghyo,Matthews, Tyler S.,Chueh, Yu‐,Lun,Ager, Joel W.,Javey, Ali WILEY‐VCH Verlag 2012 Angewandte Chemie Vol.124 No.43

<P><B>Perfekte Textur</B>: Der Einfluss der Oberflächen‐Nanotexturierung, der TiO<SUB>2</SUB>‐Passivierung und des Ru‐Cokatalysators auf die photoelektrochemische Wasserstoffentwicklung durch p‐InP‐Photokathoden wurde untersucht. Höhere Stromdichten und günstigere Onset‐Potentiale werden nach Oberflächen‐Nanotexturierung beobachtet. NHE=Normalwasserstoffelektrode.</P>

Experimental studies on elastic cooling and pyromagnetic effect ofpolyvinyl chloride sheets with defects

Yingshe Luo,Shengming Chen,Liang Zhang,Jianxin Su,Yongzhong Zhang3,Shuling Luo 한국유변학회 2012 Korea-Australia rheology journal Vol.24 No.3

Polyvinyl Chloride (PVC) sheets were made into samples with precast defects for uniaxial tensile test. The tests are carried out under room temperature with conditions of same displacement rate but different defect sizes or of same defect but different displacement rates. The local nonuniform temperature field on whole deformation area of specimen is recorded with a thermal infrared imager and the whole coupling magnetic field with thermal changes in experiments is detected and measured by a self-developed sensors system. The experimental results show that, in a complete tensile test process of PVC samples, the temperature reduction phenomenon emerges firstly in its elastic deformation stage (areas) that temperature of specimen is cooler than room temperature. And then in viscoplastic deformation period (areas), the temperature increases sharply to be obviously higher than room temperature due to the thermo-mechanical coupling effection of tensile load and viscoplastic deformation heat. These thermal variations lead a coupling pyromagnetic effect occur and the effect intensity is dependent strongly on the strain rate and/or the size of defects. The tem\-perature prejudgment conditions for materials yield are preliminary discussed based on this effect.

Biodegradable cross-linked poly(L-lactide-co-e-caprolactone) networks for ureteral stent formed by gamma irradiation under vacuum

Xiliang Liu,Song Liu,Youkun Fan,Jin Qi,Xin Wang,Wei Bai,Dongliang Chen,Chengdong Xiong,Lifang Zhang 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-

The poly(L-lactide-co-e-caprolactone) (PLCL) ureteral stent creeps and loses shape stability, increasingthe risk of stent tube dislocation. The rubbery biodegradable cross-linked PLCL networks were preparedthrough gamma irradiation under vacuum in the presence of trimethylolpropane triacrylate (TMPTA),pentaerythritol tetraacrylate (PET4A), and pentaerythritol triacrylate (PETA). At a standard sterilizationdose of 25 kGy, the gel content and network density of PLCL networks increased with increasingcrosslinking agent content (1, 3, 5, 7 wt%), and crosslinking efficiency decreased in the order ofPETA > PET4A > TMPTA. The average molecular weight (Mc ) between two crosslinks ranged from 2000to 105 g/mol. To perform the beneficial semi-interpenetrated polymer network and characterized bythe principle, the networks were processed in several doses (25, 50, 75, 100, and 125 kGy). In place ofthe Charlesby-Pinner equation, the irradiation cross-linking followed the Chen-Liu-Tang equation. ThePLCL network with 7 wt% PETA had a gel fraction of 83%, tensile strength of 34.7 MPa, and tensile setvalue as low as 5%. Furthermore, degradation in vitro was slowed down. Thus, PLCL networks with appropriateelasticity and flexibility, inherent biodegradability, and excellent biocompatibility can provide apromising alternative method for soft tissue repair engineering, such as ureteral stents.

Anomalous magnetization jumps in granular Pb superconducting films

Zhang An-Lei,Jiang Wan-Yan,Chen Xing-Hong,Zhang Xiao-Ke,Lu Wen-Lai,Chen Fei,Feng Zhen-Jie,Cao Shi-Xun,Zhang Jin-Cang,Ge Jun-Yi 한국물리학회 2022 Current Applied Physics Vol.35 No.-

In granular superconductors, the grain boundaries are closely related to the vortex dynamics and the macroscopic superconducting properties. In our research, Pb films with different grain sizes were prepared by tuning the substrate temperature. With the grain size decreasing, Pb films are prone to feature the anomalous magnetization jumps in the M − T curves, while in the M − H curves flux avalanche happens. Both phenomena appear in the same region of the H − T phase diagram and thus are considered to have the same origin. The further theoretical analysis shows that with grain size decreasing the pinning mechanism evolves from a mixed δTc and δl pinning to the δl pinning mechanism. The results shed light on the study of pinning mechanism for granular superconductors and is beneficial to the potential application of manipulating vortex pinning by regulation of intrinsic defects.

Association between Polymorphisms of MSTN and MYF5 Genes and Growth Traits in Three Chinese Cattle Breeds

Zhang, R.F.,Chen, H.,Lei, C.Z.,Zhang, C.L.,Lan, X.Y.,Zhang, Y.D.,Zhang, H.J.,Bao, B.,Niu, H.,Wang, X.Z. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.12

The objective of this study was to assess the association of polymorphisms in MSTN and MYF5 genes with growth traits in three Chinese cattle breeds. Only one homozygous animal with BB genotype at MSTN locus was observed in Jiaxian population which was at Hardy-Weinberg disequilibrium (p<0.05). The frequencies of allele A at MSTN locus and allele B at MYF5 locus in the three Chinese breeds were 0.9550/0.9730/0.9720 and 0.8275/0.7581/0.7523, respectively. Allele A at MSTN locus and allele B at MYF5 locus were dominant in these three populations. No statistically significant differences in growth traits were observed between the genotypes of the Jiaxian breed at MSTN and MYF5 loci and the Nanyang breed at MYF5 locus. However, there were statistically significant differences between the genotypes at MSTN locus of the Nanyang breed for WH, HG, HGI and HGBLR (p<0.05), and of the Qinchuan breed for BLI (p<0.05). The SNP in MYF5 had significant effects on WH and HHC of Qinchuan animals (p<0.05). These results suggest that MSTN and MYF5 are strong candidate genes that influence growth traits in cattle. Other SNPs of MSTN and MYF5 or other linked genes should also be studied, which could lead to the development of selection plans to improve the performance of Chinese cattle and also promote the breeding of genuine beef cattle in China.

Effects of dietary supplementation with different fermented feeds on performance, nutrient digestibility, and serum biochemical indexes of fattening lambs

Zhang Chen,Zhang Chongyu,Du Meiyu,Wang Yunpeng,Zhang Guiguo,이윤경 아세아·태평양축산학회 2021 Animal Bioscience Vol.34 No.4

Objective: The effects of adding fermented feed to a pelleted total mixed ration (PTMR) on the growth performance of lambs remain unclear. The present study aimed to investigate the feed efficiency and productivity of lambs that were fed PTMR containing fermented soybean meal (FSM) or wheat bran (FWB). Methods: Sixty 90-d-old hybrid lambs were randomly allocated into 12 pens (5 lambs/pen) that were randomly assigned to 4 dietary treatments (3 pens/treatment) with PTMR (basal diet), 2% FSM, or Lactobacillus- or yeast-FWB (L-FWB or Y-FWB) addition in the basal diet. Results: The findings showed that lambs fed 2% FSM supplemented diet had enhanced (p<0.05) average daily gain (ADG) and carcass yield (p = 0.015), while they had a decreased (p = 0.006) feed conversion ratio compared to that of other three groups. Inclusion of FSM or FWB in PTMR improved (p<0.05) the nutrient digestibility, while it reduced the urea nitrogen content in serum compared to the PTMR group. Additionally, the decreased ratio of N excretion to ADG (p<0.01) was observed with FSM and L-FWB supplementation compared with the PTMR and Y-FWB groups. Conclusion: In conclusion, feeding the fermented feed-supplemented diet improved nutrient digestibility and growth performance, and 2% FSM-supplemented diet exhibited superior production-promoting efficiency to lambs. Objective: The effects of adding fermented feed to a pelleted total mixed ration (PTMR) on the growth performance of lambs remain unclear. The present study aimed to investigate the feed efficiency and productivity of lambs that were fed PTMR containing fermented soybean meal (FSM) or wheat bran (FWB).Methods: Sixty 90-d-old hybrid lambs were randomly allocated into 12 pens (5 lambs/pen) that were randomly assigned to 4 dietary treatments (3 pens/treatment) with PTMR (basal diet), 2% FSM, or <i>Lactobacillus</i>- or yeast-FWB (L-FWB or Y-FWB) addition in the basal diet.Results: The findings showed that lambs fed 2% FSM supplemented diet had enhanced (p<0.05) average daily gain (ADG) and carcass yield (p = 0.015), while they had a decreased (p = 0.006) feed conversion ratio compared to that of other three groups. Inclusion of FSM or FWB in PTMR improved (p<0.05) the nutrient digestibility, while it reduced the urea nitrogen content in serum compared to the PTMR group. Additionally, the decreased ratio of N excretion to ADG (p<0.01) was observed with FSM and L-FWB supplementation compared with the PTMR and Y-FWB groups.Conclusion: In conclusion, feeding the fermented feed-supplemented diet improved nutrient digestibility and growth performance, and 2% FSM-supplemented diet exhibited superior production-promoting efficiency to lambs.

AtHAP3b Plays a Crucial Role in the Regulation of Flowering Time in Arabidopsis during Osmotic Stress

Chen, Nai-Zhi,Zhang, Xiu-Qing,Wei, Peng-Cheng,Chen, Qi-Jun,Ren, Fei,Chen, Jia,Wang, Xue-Chen Korean Society for Biochemistry and Molecular Biol 2007 Journal of biochemistry and molecular biology Vol.40 No.6

The HAP complex has been found in many eukaryotic organisms. HAP recognizes the CCAAT box present in the promoters of 30% of all eukaryotic genes. The HAP complex consists of three subunits - HAP2, HAP3 and HAP5. In this paper, we report the biological function of the AtHAP3b gene that encodes one of the HAP3 subunits in Arabidopsis. Compared with wild-type plants, hap3b-1 and hap3b-2 mutants exhibited a delayed flowering time under long-day photoperiod conditions. Moreover, the transcription levels of FT were substantially lower in the mutants than in the wild-type plants. These results imply that AtHAP3b may function in the control of flowering time by regulating the expression of FT in Arabidopsis. In a subsequent study, AtHAP3b was found to be induced by osmotic stress. Under osmotic stress conditions, the hap3b- 1 and hap3b-2 mutants flowered considerably later than the wild-type plants. These results suggest that the AtHAP3b gene plays more important roles in the control of flowering under osmotic stress in Arabidopsis.

EMI Noise Source Reduction of Single-Ended Isolated Converters Using Secondary Resonance Technique

Zhang-yong Chen,Yong Chen,Qiang Chen,Wei Jiang,Rongqiang Zhong 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.2

Aiming at the problems of large dv/dt and di/dt in traditional single-ended converters and high electromagnetic interference (EMI) noise levels, a single-ended isolated converter using the secondary resonance technique is proposed in this paper. In the proposed converter, the voltage stress of the main power switch can be reduced and the voltage across the output diode is clamped to the output voltage when compared to the conventional flyback converter. In addition, the peak current stress through the main power switch can be decreased and zero current switching (ZCS) of the output diode can be achieved through the resonance technique. Moreover, the EMI noise coupling path and an equivalent model of the proposed converter topology are presented through the operational principle of the proposed converter. Analysis results indicate that the common mode (CM) EMI noise and the differential mode (DM) EMI noise of such a converter are deduced since the frequency spectra of the equivalent controlled voltage sources and controlled current source are decreased when compared with the traditional flyback converter. Furthermore, appropriate parameter selection of the resonant circuit network can increase the equivalent impedance in the EMI coupling path in the low frequency range, which further reduces the common mode interference. Finally, a simulation model and a 60W experimental prototype of the proposed converter are built and tested. Experimental results verify the theoretical analysis.