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Configuration optimization of high velocity arc spraying gun

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 100-102页

作者： CHEN Yong-xiong ZHU Zi-xin liu yan XU Bin-shi National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China

In order to improve the in-flight characteristics of the atomizing droplets during high velocity wire arc spraying (HVAS), some changes have been operated on the original design of the HVAS gun configuration. A comparative study was carried out to investigate the microstructure and properties of the coatings produced by the original design spraying gun and the modified one, using 3Cr13 wires of 3 mm in diameter. The characteristics of their jets were examined during spraying. The results indicate that, the included angle between the two wires and the distance from the nozzle to the meeting point of the two vires may have a strong influence on the characteristics of the in-flight droplets and then the coatings. The jet divergence is found to be lower than that of the original one (about 12° against 25°). By modified gun, the adhesion strength, the microhardness and porosity of the coating deposited by modified gun are increased by 39% and 9% respectively. And the porosity of the coatings is decreased by 57%.

关键词： high velocity arc spraying gun configuration optimization coating

Heat transfer analysis of atomized droplets during high velocity arc spraying

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中国有色金属学会会刊：英文版 2004年第Z1期14卷 103-105页

作者： ZHU Zi-xin liu yan CHEN Yong-xiong XU Bin-shi ZHANG Wei National Key Laboratory for Remanufacturing Academy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for RemanufacturingAcademy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for RemanufacturingAcademy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for RemanufacturingAcademy of Armored Forces Engineering Beijing 100072 China National Key Laboratory for RemanufacturingAcademy of Armored Forces Engineering Beijing 100072 China

The heat transfer problem of the atomized droplets during high velocity arc spraying (HVAS) was modeled and solved by a numerical method using a Fe-Al alloy, and the influences of several important process parameters on the heat transfer behaviors of the atomized droplets were analyzed. The results show that the initial cooling rates of different size droplets range from 105 to 107 K/s, thus producing the coating microstructure with the features of rapid solidification. The droplet size, atomization gas pressure and droplet superheat have great influences on the heat transfer behavior of the droplet. The droplet temperature and cooling rate are much sensitive to the droplet sizes, but insensitive to the atomization gas pressure and droplet superheat. It can be predicted that the properties of HVAS coatings will be improved by decreasing droplet size as well as increasing atomization gas pressure and droplet superheat in certain extents.

关键词： high velocity arc spraying atomized droplet heat transfer numerical simulation

Gauge Transformation and Constraint Induced Operator Ordering for Charged Rigid Planar Rotator in Uniform Magnetic Field

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Communications in Theoretical Physics 2006年第5X期46卷 843-844页

作者： LAI Mei-Mei WANG xin XIAO yan-Ping liu Quan-Hui School for Theoretical Physics and Department of Applied Physics Hunan University Changsha 410082 China

When the motion of a particle is constrained, excess terms exist using hermitian form of Cartesian momentum pi （i=1, 2,3） in usual kinetic energy （1/2/μ）∑ pi^2 , and the correct kinetic energy turns out to be （1/2μ） ∑1/ fipi f ipi, where fi are dummy factors in classical mechanics and nontrivial in quantum mechanics. In this paper the explicit form of the dummy functions fi is given for a charged rigid planar rotator in the uniform magnetic field with different gauge chosen. Under different gauges, we have different sets of dummy factors. It means that these factors do not have direct observable effect.

关键词： operator ordering gauge transformation quantum mechanics

Risk assessment of corroded casing based on analytic hierarchy process and fuzzy comprehensive evaluation

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Petroleum Science 2021年第2期18卷 591-602页

作者： Sheng-Shan Chen Han-Xiang Wang Hao Jiang Ya-Nan liu yan-xin liu Xiao-Xiao Lv College of Mechanical and Electronic Engineering China University of Petroleum(East China)Qingdao266580China

Casing corrosion during CO2 injection or storage results in significant economic loss and increased production ***,in this paper,a corroded casing risk assessment model based on analytic hierarchy process and fuzzy comprehensive evaluation is established to identify potential risks in ***,the corrosion rate and residual strength characteristics are analyzed through corrosion tests and numerical simulations,respectively,to determine the risk factors that may lead to an ***,an index system for corroded casing risk evaluation is established based on six important factors:temperature,CO2 partial pressure,flow velocity,corrosion radius,corrosion depth and wellhead ***,the index weights are calculated via the analytic hierarchy ***,the risk level of corroded casing is obtained via the fuzzy comprehensive *** corroded casing risk assessment model has been verified by a case well,which shows that the model is valuable and *** provides an effective decision-making method for the risk evaluation of corroded casing in CO2 injection well,which is conductive to improve the wellbore operation efficiency.

关键词： Corrosion rate Residual strength Analytic hierarchy process Fuzzy comprehensive evaluation

Ferrets: A powerful model of SARS-CoV-2

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Zoological Research 2023年第2期44卷 323-330页

作者： yan Zhao Chang-Le Wang Zhi-Yun Gao Hong-Xiu Qiao Wei-Jie Wang xin-yan liu Xia Chuai Department of Pathogenic Biology Hebei Medical UniversityShijiazhuangHebei 050017China Institute of Medicine and Healthy of Hebei Medical University ShijiazhuangHebei 050017China Department of Oncology Hebei Provincial Thoracic HospitalShijiazhuangHebei 050010China

The rapid spread of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2) in recent years not only caused a global pandemic but resulted in enormous social,economic,and health burdens *** considerable efforts to combat coronavirus disease 2019(COVID-19),various SARS-CoV-2 variants have emerged,and their underlying mechanisms of pathogenicity remain largely ***,effective therapeutic drugs are still under ***,an ideal animal model is crucial for studying the pathogenesis of COVID-19 and for the preclinical evaluation of vaccines and antivirals against SARS-CoV-2 and variant ***,several animal models,including mice,hamsters,ferrets,and nonhuman primates(NHPs),have been established to study *** them,ferrets are naturally susceptible to SARS-CoV-2 infection and are considered suitable for COVID-19 ***,we summarize recent developments and application of SARS-CoV-2 ferret models in studies on pathogenesis,therapeutic agents,and vaccines,and provide a perspective on the role of these models in preventing COVID-19 spread.

关键词： SARS-CoV-2 COVID-19 Animal models Ferret Angiotensin-converting enzyme 2(ACE2)receptor

Changes in Unsaturated Levels of Fatty Acids in Thylakoid PSII Membrane Lipids During Chilling-induced Resistance in Rice

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Journal of Integrative Plant Biology 2007年第4期49卷 463-471页

作者： Su-Qin Zhu Chun-Mei Yu xin-yan liu Ben-Hua Ji De-Mao Jiao Institute of Bioengineering Nantong University Nantong 226007 China College of Life Sciences Nantong University Nantong 226007 China Institute of Agrobiological Genetics and Physiology Jiangsu Academy of Agricultural Sciences Nanjing 210014 China

Temperature is one of the abiotic factors limiting growth and productivity of plants. In the present work, the effect of low non-freezing temperature, as an inducer of ＂chilling resistance＂, was studied in three cultivars of rice （Oryza sativa L.）, japonica cv. 9516 （j-9516）, the two parental lines of superhigh-yield hybrid rice between subspecies, Peiai/E32 （ji-PE）, and the traditional indica hybrid rice Shanyou 63 （i-SY63）. Leaves of chill-treated rice showed chilling-induced resistance, as an increase of their low-temperature tolerance was measured using chlorophyll fluorescence measurements, revealing a change in photosystem II （PSII） efficiency. After 5 d of exposure to 11 ~C under low light （100 pmol·m^-2·s^-1）, levels of unsaturated fatty acids in PSII thylakoid membrane lipids decreased during the initial 1-2 d, then increased slowly and reached 99.2%, 95.3% and 90.1% of the initial value （0 d） in j-9516, ji-PE and i-SY63, respectively, on the fifth day. However, under medium light （600 μmol·m^-2·s^-1）, all cultivars experienced similar substantial photoinhibition, which approached steady state levels after a decline in levels of unsaturated fatty acids in PSII thylakoid membrane lipids to about 57.1%, 53.8% and 44.5% of the initial values （0 d） in j-9516, ji-PE and i-SY63 on the fifth day. Under either chilling-induced resistance （the former） or low temperature photoinhibition （the latter） conditions, the changes of other physiological parameters such as D1 protein contents, electron transport activities of PSII （ETA）, Fv/Fm, xanthophyl cycle activities expressed by DES （deepoxide state） were consistent with that of levels of unsaturated fatty acids in PSII thylakoid membrane lipids. So there were negative correlations between saturated levels of fatty acids （16：1（3t）, 16：0, 18：0）, especially the 16：1（3t） fatty acid on thylakoid membrane and other physiological parameters, such as D1 protein contents, ETA and （A＋Z）/（A＋V＋Z）. A specific role of desaturation o

关键词： chilling-induced resistance D1 protein rice thylakoid PSII membrane lipids unsaturated fatty acids xanthophyl cycleactivity.

Total Synthesis of N-Methylsansalvamide A

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Chinese Chemical Letters 2006年第6期17卷 761-764页

作者： Shou xin liu yan Lou GENG Xia TIAN Xiao Li ZHEN Jian Rong HAN College of chemical ＆ pharmaceutical Engineering Hebei University of Science ＆ Tecnnology Shijiazhuang 050018

Total synthesis of N-methylsansalvamide A was accomplished in solution phase by a convergent approach. An N-Boc-td-depsipepide 6 and a dipeptide ester 10 were prepared in the yield of 89% and 91%, respectively. Cycliz... 详细信息

关键词： Synthesis N-methylsansalvamide A solution phase cyclic depsipeptide.

Investigation of Epstein-barr virus in Chinese colorectal tumors

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World Journal of Gastroenterology 2003年第11期9卷 2464-2468页

作者： Huan-xin liu yan-Qing Ding xin Li Kai-Tai Yao, Department of Pathology, the First Military Medical University, Guangzhou 510515, Guangdong Province, China Department of Pathology the First Military Medical University Guangzhou 510515 Guangdong Province China.

AIM: To elucidate the association of Epstein-Barr virus (EBV) with colorectal tumors and to demonstrate whether infection of EBV existed in different stages of colorectal tumors involves in the ***: One hundred and thirty paraffin-embedded tissues of colorectal tumors were classified into 5 groups:26 adenomas, 23 adenomas complicated with dysplasia, 22 adenomas complicated with carcinomatous, 36 colon carcinoma and 23 HNPCC, were examined by PCR, IHC and ISH, ***: EBV DNA was detected by PCR in 26 cases out of the 130 specimens, including 5 cases of adenomas, 5 adenomas complicated with dysplasia, 5 adenomas complicated with carcinomatous, 7 colorectal carcinoma and 4 HNPCC. IHC detection showed the expression of LMP1 in 7 cases, including 1 adenoma, 1 adenoma with dysplasia, 1 HNPPC, 2 adenomas complicated with carcinomatous, and 2 colorectal carcinomas. The expression of EBER1 detected by ISH was positive in 6 cases, including 1 adenoma with dysplasia, 2 adenomas complicated with carcinomatous and 3 colorectal carcinomas. There were no significant differences among the results of PCR, IHC and ISH in the 5 groups. In all cases of HNPCC, none of the tumor cells showed positive signals of EBER1, but some EBV-positive tumor infiltrating lymphocytes were found in 2 of 23 ***: Our results showed that infection of EBV exists in human colorectal tumors, which indicates that EBV may be involved in the carcinogenesis of colorectal tumors but does not play an important role. The mechanisms need to be clarified further.

关键词：爱泼斯坦-巴尔病毒结直肠癌 PCR 肿瘤生成临床研究

Removal of Antibiotic Resistance of Live Vaccine Strain Escherichia coli MM-3 and Evaluation of the Immunogenicity of the New Strain

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Acta Biochimica et Biophysica Sinica 2006年第12期38卷 844-856页

作者： Sheng-Ling YUAN Peng WANG Hao-Xia TAO Xiang-xin liu yan-Chun WANG De-Wen ZHAN Chun-Jie liu Zhao-Shan ZHANG* Beijing Institute of Biotechnology,Beijing 100071,China Beijing Institute of BiotechnologyBeijing 100071 China

MM-3 was a live vaccine strain candidate for protecting neonatal piglets from *** in the 1980s,a high degree of protection from colibacillosis was afforded to piglets in a challengestudy and field *** MM-3 had a drawback of carrying the antibiotic resistance gene (chloramphenicolacetyltransferase gene,cat).The introduction of a host-plasmid balanced lethal system into the vaccine wasa good idea to solve the *** λ-Red recombination system was adopted in this study to realize thereplacement of cat by aspartate-semialdehyde dehydrogenase gene (asd) in the plasmid *** newplasmid named pMMASD was introduced into an Escherichia coli strain χ6097 and Salmonella typhimuriumχ4072 where the asd gene had been knocked out in their *** in an Erlenmeyer flask,expression levels of two antigens K88ac fimbriae and heat-labile enterotoxin B subunit (LTB) in cell lysatewere similar among MM-3,χ4072(pMMASD) and χ6097(pMMASD).However,χ4072(pMMASD) possessedthe more effective secretion mechanism to transport LTB enterotoxin into culture *** relatively higherstability of pMMASD in Salmonella typhimurium χ4072 than that of pMM085 in MM-3 was determined bothin vitro in the absence of selective pressure,and in vivo following oral *** immunization ofBALB/c mice with χ4072(pMMASD) or χ6097(pMMASD) was sufficient to elicit IgA responses in mucosaltissues as well as systemic IgG antibody responses to the K88 fimbriae,while MM-3 failed to elicit specificantibody responses to K88 fimbriae in mucosal *** three live strains,only χ4072(pMMASD)could develop strong humoral responses against LTB *** results suggest that χ4072(pMMASD)is expected to be a promising live vaccine strain.

关键词： λ-Red recombination system host-plasmid balanced lethal system K88ac fimbriae LTB enterotoxin ETEC live vaccine strain Salmonella