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.

Wireless power transfer system for angled concave conditions utilizing quasi-bowl-shaped couplers

Chen, Chen,Li, Jiangui,Wang, Longyang,Nie, Hui,Li, Qiang The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.7

Wireless power transfer (WPT) is favored by consumers due to its convenience, safety, and flexible layout. Circular and rectangular coils are the most common coil structures in WPT systems. However, they are not suitable for installation conditions with angled groove areas such as railways, conveyors, and so on. To fully utilize installation space and to improve transfer efficiency, this paper has proposed a quasi-bowl-shaped (QBS) magnetic coupler, which can suitably fit on angled grooves. First, a QBS coupler model was presented. Second, formulas of its spatial magnetic field density were derived. Third, the influences of the bending distance and bending angle on the coupler coefficient were analyzed. Fourth, five magnetic core types were presented and analyzed for coupler optimization. Finally, QBS WPT performances were tested on a newly built experiment platform. Experimental results show that the QBS coupler can realize a constant transfer efficiency of 92.36% at an axial distance of 6 cm, and it can realize a constant transfer efficiency of 84.17% at an axial distance of 10 cm.

Prediction of the transient energy response for complex vibro-acoustic systems

Qiang Chen,Qingguo Fei,Yanbin Li,Shaoqing Wu,Xuan Yang 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2

As research works of the transient statistical energy analysis (TSEA) and transient local energy approach (TLEA) mostly focus on simple structures, TSEA and TLEA are adopted to quantify the transient response of a complex vibro-acoustic system at the mid-high frequency range in this paper. Numerical examples of a coupled oscillator system, an L-shaped plate, and a launch vehicle fairing model are conducted to demonstrate the effectiveness and accuracy of TSEA and TLEA. The computational precision of TSEA and TLEA is verified by the analytical solution and finite element method. Furtherly, the transient energy responses of subsystems with different coupling ratios between subsystems are investigated. Results show that TLEA has a better performance than TSEA. With the increasing coupling ratio between subsystems, the rise time and peak energy of transient energy response of subsystems decrease gradually. Both ratios of rise time and peak energy predicted by TLEA to these of the TSEA increase as the rising of the coupling ratio.

Characterization of proteolysis in muscle tissues of sea cucumber Stichopus japonicus

Chen-Chen Zhao,Yang Yang,Hai-tao Wu,Zhi-Mo Zhu,Yue Tang,Cui-Ping Yu,Na Sun,Qiang Lv,Jia-Run Han,Ao-Ting Li,Jia-Nan Yan,Yue Cha 한국식품과학회 2016 Food Science and Biotechnology Vol.25 No.6

The proteolysis in muscle tissues of sea cucumber Stichopus japonicus (sjMTs) was characterized. The proteins from sjMTs were primarily myosin heavy chains (MHCs), paramyosin (Pm), and actin (Ac) having a molecular mass of approximately 200, 98, and 42 kDa, respectively. Based on SDS-PAGE analysis and quantification of trichloroacetic acid (TCA)-soluble peptides released, degradation of muscle proteins from sjMTs was favorable at pH 5 and 50°C. Proteolysis of MHCs was mostly inhibited by cysteine protease inhibitors, including trans-epoxysuccinyl-L-leucyl-amido (4- guanidino) butane (E-64) and antipain (AP). E-64 and AP completely inhibited the degradation of Pm and Ac, while iodoacetic acid showed a partially inhibitory effect. These results indicated that the proteolysis of sjMTs was mainly attributed to cysteine proteases. Avoidance of setting the tissues at 40–50oC and slightly acidic condition and inhibition of cysteine proteases are helpful for decreasing sea cucumber autolysis.

Detection of Methanol in Power Transformer Oil Using Spectroscopy

Qiang Fu,Lei Peng,Li Li,Musong Lin,Yaohong Zhao,Shengli Li,Chen Chen 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.2

Oil-paper insulation in transformers plays an important role in the operation of power grid. At present, the aging (life assessment) of transformers are mainly conducted based upon the degree of polymerization, concentration of furfural, and the gas analysis of CO and CO 2 in the transformer oil. However, these techniques lack sensitive response, especially in the early aging of oil-paper insulation. Methanol as a new indicator to evaluate the aging of insulating paper, is getting more and more attention. An evaluation method based on the measurement of methanol concentration using ultraviolet–visible spectrometer was proposed in this work. After the extraction from transformer oils, the methanol was oxidized using potassium permanganate. Then, chromotropic acid was used to react with the oxidation products (formaldehyde) to form a mauve clathrate, fi nally, the methanol content was measured using the spectroscopy. Diff erent from traditional spectroscopy which calculate only by absorbance at the characteristic wavelength, this paper use the partial least squares method, obtain the relationship between the absorbance at selected regions and the concentration of methanol. The minimum detection limit for the proposed method was 10 ppb, whereas the correlation coeffi cient for the relationship between the absorbance and the concentration of methanol was as high as 0.99.

A Rare Case of Extensive Erythrophagocytosis by Pathological Erythroblasts in a Patient With Myelodysplastic Syndrome

Qiang Xing,Li Jia,Chen Siyu,Gou Yang,Wang Ping,Chen Xueyan 대한진단검사의학회 2023 Annals of Laboratory Medicine Vol.43 No.3

Prevalence and Genotype Distribution of Human Papillomavirus Infections in Women Attending Hospitals in Chaozhou of Guangdong Province

Chen, Qiang,Luo, Zhao-Yun,Lin, Min,Lin, Qi-Li,Chen, Chan-Yu,Yang, Chun,Xie, Long-Xu,Li, Hui,Zheng, Jia-Kun,Yang, Li-Ye,Ju, Gui-Zhi Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

Background: Human papillomavirus (HPV) infection is the main cause of cervical cancer. Limited epidemiologic data of HPV prevalence are available for women attending hospitals in southern China. This study aimed to evaluate the profiles of HPV infection and cytology status in gynecological outpatients in Chaozhou City. Methods: A total of 2833 eligible women were enrolled. The HPV GenoArray test was used for HPV detection and genotyping. Nearly one half of the HPV positive women received liquid-based cytology test. Logistic regression analysis was performed to assess the predictable effects of age and genotype for categories of abnormal cytology. Results: The prevalence of overall, high-risk, and low-risk HPV infection were 24.5%, 19.5% and 8.4%, respectively. A U-shaped age-specific prevalence curve was observed in overall HPV and high-risk HPV, but not in low-risk HPV, which declined with age increasing. The 6 most common high-risk HPV type in descending order, were types 52, 16, 58, 18, 68, and 33. Age and HPV genotype were both important determinants of abnormal cytology incidence, the older women (>45 years) and those infected with HPV type 16 and/or 18 having the highest risk for abnormal cytology. Conclusion: Our findings support the hypothesis that second-generation HPV prophylactic vaccines including HPV-52 and -58 may offer higher protection for women residing in Chaozhou and neighboring cities in Guangdong.

Inhibitory Effects of α-Pinene on Hepatoma Carcinoma Cell Proliferation

Chen, Wei-Qiang,Xu, Bin,Mao, Jian-Wen,Wei, Feng-Xiang,Li, Ming,Liu, Tao,Jin, Xiao-Bao,Zhang, Li-Rong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.7

Background: Pine needle oil from crude extract of pine needles has anti-tumor effects, but the effective component is not known. Methods: In the present study, compounds from a steam distillation extract of pine needles were isolated and characterized. Alpha-pinene was identified as an active anti-proliferative compound on hepatoma carcinoma BEL-7402 cells using the MTT assay. Results: Further experiments showed that ${\alpha}$-pinene inhibited BEL-7402 cells by arresting cell growth in the G2/M phase of the cell cycle, downregulating Cdc25C mRNA and protein expression, and reducing cycle dependence on kinase 1(CDK1) activity. Conclusion: Taken together, these findings indicate that ${\alpha}$-pinene may be useful as a potential anti-tumor drug.

An Exploration of the Coverage of People’s Daily on the “Belt and Road” Initiative-related Issues in Pakistan from a Perspective of Moral Concern and Balance of Interests

Qiang Jin(Qiang Jin),Haibao Yang(Haibao Yang),JinXiao Chen(JinXiao Chen) 아시아사회과학학회 2023 Jornal of Asia Social Science Vol.10 No.1

China-Pakistan relations have been renewed for a long time, especially after the “Belt and Road” initiative and the “China-Pakistan Economic Corridor” were put forward, the cooperation between the two countries has continued to deepen and become more solid. “People's Daily” is best at grasping the situation at home and abroad, and it can also reflect the will of the country, constantly weighing between “morality” and “interest”. Its reports on Pakistan are representative among domestic media. Reports show an irregular trend, with fluctuations and declines. There are various types of reports, but they are mainly news, with the layout at the front. The length is relatively long, and the sources of news are more authoritative. In terms of content, the main body of the report is clear, and the leader’s news accounts for a large proportion. China-Pakistan economic cooperation and the China-Pakistan Economic Corridor are the main ones, and positive reports are mainly used. There are more neutral and negative reports in social news. In the cultural field, education exchanges and Youth exchanges are the main focus, and the military field is mainly military cooperation and counter-terrorism. Relevant reporting can also increase the amount of in-depth reporting, provide diversity information, and focus more on cultural reporting.

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

Chen, Zhangyong,Chen, Yong,Chen, Qiang,Jiang, Wei,Zhong, Rongqiang The Korean Institute of Power Electronics 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.