Comparative Study of DC Breakdown and Space Charge Characteristics of Insulation Paper Impregnated with Natural Ester and Mineral Oil

Hao, Jian,Zou, Run-Hao,Liao, Rui-Jin,Yang, Li-Jun,Liao, Qiang,Zhu, Meng-Zhao The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

Natural ester is a suitable substitute for mineral oil and has been widely used in AC transformer in many countries. In order to further application of natural ester in direct current (DC) equipment, it is needed to investigate its long term insulation property under DC condition. In this paper, a thermal ageing experiment was conducted for both mineral oil-paper and natural ester-paper insulation. The DC breakdown and space charge characteristics of insulation paper impregnated with natural ester and mineral oil was compared. Results show that the resistivity of the paper immersed in natural ester and mineral oil both increase as the ageing goes on. While insulation paper impregnated with natural ester has higher resistivity and DC breakdown voltage than the paper impregnated with mineral oil. The DC breakdown voltage for the oil impregnated insulation paper being DC pre-stressing is higher than that without pre-stressing. The average DC breakdown field strength difference between the test with pre-stressing and without pre-stressing clearly shows that there is an apparent enhancement effect for the homo-charge injection on the DC breakdown.

Comparative Study of DC Breakdown and Space Charge Characteristics of Insulation Paper Impregnated with Natural Ester and Mineral Oil

Jian Hao,Run-Hao Zou,Rui-Jin Liao,Li-Jun Yang,Qiang Liao,Meng-Zhao Zhu 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

Natural ester is a suitable substitute for mineral oil and has been widely used in AC transformer in many countries. In order to further application of natural ester in direct current (DC) equipment, it is needed to investigate its long term insulation property under DC condition. In this paper, a thermal ageing experiment was conducted for both mineral oil-paper and natural ester-paper insulation. The DC breakdown and space charge characteristics of insulation paper impregnated with natural ester and mineral oil was compared. Results show that the resistivity of the paper immersed in natural ester and mineral oil both increase as the ageing goes on. While insulation paper impregnated with natural ester has higher resistivity and DC breakdown voltage than the paper impregnated with mineral oil. The DC breakdown voltage for the oil impregnated insulation paper being DC prestressing is higher than that without pre-stressing. The average DC breakdown field strength difference between the test with pre-stressing and without pre-stressing clearly shows that there is an apparent enhancement effect for the homo-charge injection on the DC breakdown.

The Current Situation and Suggestions of Physical Education Curriculum for All Primary School Teachers in Rural Chongqing

邹,浩(Zou Hao) 아시아사회과학학회 2022 International Science Research Vol.2 No.1

小学全科教师是针对解决农村地区师资矛盾问题的一个新的教师岗位, 对满足农村地区适龄学生的教育需要具有重要的意义。在重庆, 开设有小学全科教师的院校众多, 这些院校的培养方式和教育形式各具特色, 但是它们在小学全科教师体育课程设置方面比较集中地存在着一些问题。体育课程是以身体练习为手段, 通过合理的体育教育和科学的体育锻炼过程, 达到增强体质。增进健康和提高体育素养为主要目标的公共必修课程。基于此, 本文通过文献资料法和调查法, 分析重庆农村小学全科教师体育课程设置现状, 研究各个高校关于全科教师体育课程的设置, 为重庆农村小学全科教师体育课程设置现状提出建议。 The primary school generalist teacher is a new teaching position aimed at solving the problem of conflicting teacher qualifications in rural areas, and is of great significance in meeting the educational needs of school-age students in rural areas. In Chongqing, there are many institutions that offer primary school generalist teachers, and these institutions have different training methods and forms of education, but they have a relatively high concentration of problems with the physical education curriculum for primary school generalist teachers. The physical education curriculum is a physical exercise as a means to enhance physical fitness through a rational physical education and scientific physical exercise process. It is a compulsory public course with the main objective of enhancing health and improving physical literacy. Based on this, this paper analyses the current situation of the physical education curriculum for general education teachers in rural primary schools in Chongqing through the literature method and survey method, studies the settings of the physical education curriculum for general education teachers in various universities, and makes suggestions for the current situation of the physical education curriculum for general education teachers in rural primary schools in Chongqing.

Effect of Acute hypoxia on Plasma Endothelin in Rats

Hao Weiwei,Yu Qifu,Zao Yuntao,Qin Shuqing,Zou Zhengmou,Yu Songhai,Guo Qiyu 한국항공우주의학협회 1994 항공우주의학회지 Vol.4 No.1

Temperature distribution analysis of steel box-girder based on long-term monitoring data

Hao Wang,Qingxin Zhu,Zhongqin Zou,Chenxi Xing,Dongming Feng,Tianyou Tao 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.5

Temperature may have more significant influences on structural responses than operational loads or structural damage. Therefore, a comprehensive understanding of temperature distributions has great significance for proper design and maintenance of bridges. In this study, the temperature distribution of the steel box girder is systematically investigated based on the structural health monitoring system (SHMS) of the Sutong Cable-stayed Bridge. Specifically, the characteristics of the temperature and temperature difference between different measurement points are studied based on field temperature measurements. Accordingly, the probability density distributions of the temperature and temperature difference are calculated statistically, which are further described by the general formulas. The results indicate that: (1) the temperature and temperature difference exhibit distinct seasonal characteristics and strong periodicity, and the temperature and temperature difference among different measurement points are strongly correlated, respectively; (2) the probability density of the temperature difference distribution presents strong non-Gaussian characteristics; (3) the probability density function of temperature can be described by the weighted sum of four Normal distributions. Meanwhile, the temperature difference can be described by the weighted sum of Weibull distribution and Normal distribution.

Black phosphorus nanosheets‑based effective electrochemical sensor for uric acid detection

Hao Wang,Haitao Wang,Jingjing Yang,Pramitha Yuniar Diah Maulida,Jing Zou,Arramel,Can Wu,Jizhou Jiang 한국탄소학회 2023 Carbon Letters Vol.33 No.7

Black phosphorus (BP) is incorporated in the electrochemical detection of uric acid (UA) to form few layers of BP nanosheets (BPNS)-modified glassy carbon electrodes (BPNS/GCE), investigated by means of ultrasound-assisted liquid-phase exfoliation. We find a significant increase in the peak current magnitude and positive potential shift in the electrochemical response of BPNS/GCE, which may be attributed to the larger specific surface area and good charge transfer ability of BPNS. Further, the electrochemical response of BPNS/GCE is evaluated under different conditions to achieve the optimal conditions. UA detection using differential pulse voltammetry (DPV) shows linear response within the range of 1–1000 μM with a detection limit of 0.33 μM. This work reveals new applications of BP nanomaterials in the electrochemical sensing, thereby promoting further advancement in terms of practical applications of two-dimensional nanomaterials.

Influence of Porosity on Mechanical Behavior of Porous Cu Fabricated via De‑Alloying of Cu–Fe Alloy

Lijie Zou,Fei Chen,Hao Wang,Qiang Shen,Enrique J. Lavernia,Lianmeng Zhang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1

We report on a study of the mechanical behavior of porous Cu containing micron-sized pores and fabricated by de-alloyingof a Cu–Fe precursor alloy. Our results show that the minimum volume fraction of pores that can be obtained by using anapproach that involves de-alloying of a Cu–Fe precursor alloy is approximately 40 vol%. Moreover, the average pore sizeformed by de-alloying Cu–Fe of varying compositions is in the range of 1.5–4.0 μm. Our mechanical behavior results revealthat the yield stress increases from 3.9 to 58.6 MPa as the volume fraction of porosity decreases from 78.9% to 39.3%. Moreover, our data shows that the influence of porosity on the relative yield stress and relative Young’s modulus conformsto the scaling equations of Gibson and Ashby as formulated for open-cell porous metals. The pore cell characteristics anddeformation modes of porous Cu produced by de-alloying Cu–Fe alloys were discussed in the context of the observed fluctuationsin the value of the constants C and n in the Gibson-Ashby scaling equation. The evolution of microstructure duringcompressive deformation of porous Cu was studied and the results reveal an increase in the fraction of low-angle grainboundaries, an increase in the number of twins and a decrease in the average grain size with increasing strain from 0% to 70%.

Preparation and drug release behavior of pH-responsive bovine serum albumin-loaded chitosan microspheres

Xue Zou,Xiaowen Zhao,Lin Ye,Qi Wang,Hao Li 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

A novel inverse emulsion-ionic crosslinking approach was adopted to prepare pH-responsive chitosanmicrospheres and effect of preparation technique, such as chitosan concentration, emulsifierconcentration, water/oil ratio and homogenization speed, on the morphology and property of themicrospheres were investigated. The chitosan microspheres with spherical in shape, smooth surface,high productivity and promising pH responsiveness were obtained. On this basis, bovine serum albumin(BSA)-loaded chitosan microspheres was prepared to test the drug release behavior in buffers withdifferent pH values. BSA-chitosan microspheres with particle sizes in range from 5 to 10mmreleased BSAslowly in neutral medium and released rapidly in acidic medium, and exhibited obviously pH-responsiverelease behavior. Korsmeyer–Peppas model can be used for describing BSA release kinetics from chitosanmicrospheres, which corresponded with a Fickian release behavior, and the diffusion through theswelling of chitosan microspheres was the main factor in controlling BSA release.

Quantitative Proteomic Analysis Reveals Up-Regulation of Type I Collagen During Tumorigenesis of Colorectal Cancer

Xia Zou,Bo Feng,Taotao Dong,Binbin Tan,Hao Shen,Xiu Zhang,Menghui Zhang,Minhua Zheng,Yan Zhang 한국당과학회 2012 한국당과학회 학술대회 Vol.2012 No.1

Colorectal cancer (CRC) is one of the most prevalent cancers in the world with high mortality and morbidity rates. In this study, we have performed comparative proteomic profiling of sera from CRC patients at stage I (n=17), stage II (n=40), stage III (n=24) and healthy subjects (n=25) to gain a global view of protein expression change during CRC tumorigenesis and provide potential targets for CRC diagnosis and treatment. As a result, a total of 93 proteins were found differentially expressed in CRC patients with a label-free quantitative APXE method. After GO and KEGG pathway analysis, those proteins most frequently involved in ECM-receptor interaction, complement and coagulation cascades. As important as components of ECM, we found several collagens in CRC serum had been changed from tumor stage I to IV. And the validation of collagen I (COL1) at RNA and protein expression level shown extremely comparable to pooled serum proteomic results using independent 26 paired tumor and matched normal colorectal tissues. Those findings indicated that the change of collagen I observed in serum were indeed from pathogenic lesion of colorectal tissue. Moreover, we further investigated serum levels of COL1, PICP (the synthesis indicator) and CTx (the breakdown indicator) in 77 CRC patients and 33 normal controls by ELISA. The results showed PICP and CTx were better for discriminating normal from cancer groups as well as non-metastatic from metastatic tumor than COL1. Finally, we evaluated the expression of MMPs in paired tumor and normal tissues from patients with different stages. Notably, the expression of MMP1, 7 and 14 were remarkably enhanced in carcinoma tissues and the trend were parallel with the progression of tumor stage. The expression of E-cadherin and CDX2, which had been considered as targets of COL1 in cell models, were also verified in tissues and displayed decrease in tumor. Overall, COL1 might be affected by MMP1, 7, 14 and had effects on cell adhesion and differentiation through E-cadherin and CDX2.

TERT rs2736098 Polymorphism and Cancer Risk: Results of a Meta-analysis

Qi, Hao-Yu,Zou, Peng,Zhao, Lin,Zhu, Jue,Gu, Ai-Hua Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.7

Objective: Several studies have demonstrated associations between the TERT rs2736098 single nucleotide polymorphisms (SNPs) and susceptibility to cancer development. However, there are conflicting results. A systematic meta-analysis was therefore performed to establish the cancer risk associated with the polymorphism. Methods: In this meta-analysis, a total of 6 case-control studies, including 5,567 cases and 6,191 controls, were included. Crude odds ratios with 95% confidence intervals were used to assess the strength of associations in several genetic models. Results: Our results showed no association reaching the level of statistical significance for overall risk. Interestingly, in the stratified analyses (subdivided by ethnicity), significantly increased risks were found in the Asian subgroup which indicates the TERT rs2736098 polymorphism may have controversial involvement in cancer susceptibility. Conclusions: Overall, this meta-analysis indicates that the TERT rs2736098 polymorphism may have little involvement in cancer susceptibility.