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Analysis of structural hot-spot stress in orthotropic plates

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Engineering Sciences 2012年第3期10卷 88-92页

作者： chen Ce ji Bohai Xu Hanjiang College of Civil and Transportation Engineering Hohai University Nanjing 210098 China jiangsu Provincial Yangtze River Highway Bridge Construction Commanding Department Taizhou Jiangsu 225321 China

On the basis of the actual steel deck structure of Taizhou Bridge, this paper carries out hot-spot stress analysis on some key spots by using the finite element model which simulates local structure of orthotropic steel bridge decks. A finite element model is established for local structure of orthotropic steel bridge decks, and in the analysis of linear elasticity of the structure, face load is employed to simulate the loads from vehicle wheels. Analysis results show that main stresses are relatively heavy at the joints between diaphragm plates, top plates and U-shaped ribs and the joints between diaphragm plates and U-shaped ribs. These joints shall be regarded as key points for hot-spot stress analysis. Different mesh densities are adopted in the finite element model and the main stresses at different hot spots are contrasted and linear extrapolation is carried out using extrapolation formulae. Results show that different mesh densities have different influences on the hot-spot stresses at the welded seams of U-shaped ribs. These influences shall be considered in calculation and analysis.

关键词： steel bridge deck local structure mesh density hot-spot stress

Preparation of pre-reduced pellet using pyrite cinder containing nonferrous metals with high temperature chloridizingreduction roasting technology—Effect of CaCl_2 additive

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Journal of Central South University 2015年第11期22卷 4154-4161页

作者：陈栋朱德庆洪澜陈瑶许继芳伍凌 Shagang School of Iron and Steel Soochow University School of Minerals Processing and Bioengineering Central South University School of Mechanical and Electric Engineering Soochow University

The role of CaCl2 during the high temperature chloridizing-reduction roasting process was investigated, aiming at acquiring high strength blast furnace burden with high iron grade and low nonferrous metals content. The effects of CaCl2 dosage on pelletizing, preheating and reduction were investigated. The results show that CaCl2 can improve the wet drop strength but reduces the thermostability of pyrite cinder green balls. When the dosage of CaCl2 exceeds 1%, the compressive strength of preheated pellets decreases while the growth of iron oxide particles is improved. Furthermore, the compressive strength of pre-reduced pellets increases but the metallization degree of pre-reduced pellets decreases with CaCl2 additive. The removal tests indicate that Zn can be removed completely without CaCl2 additive, Cu is removed only under the condition with CaCl2 additive and part of Pb must be removed by CaCl2 additive.

关键词： pyrite cinder CaCl2 additive pelletizing chloridis

Surgical management in biliary restricture after Roux-en-Y hepaticojejunostomy for bile duct injury

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World Journal of Gastroenterology 2007年第48期13卷 6598-6602页

作者： ji-Qi Yan cheng-Hong Peng jia-Zeng Ding Wei-Ping Yang Guang-Wen Zhou Yong-Jun chen Zong-Yuan Tao Hong-Wei Li Department of Surgery Ruijin Hospital School of Medicine Shanghai Jiaotong University Shanghai 200025 China

AIM: To discuss the surgical method and skill of biliary restricture after Roux-en-Y hepaticojejunostomy for bile duct injury. METHODS: From November 2005 to December 2006, eight patients with biliary restricture after Roux-en-Y hepaticojejunostomy for bile duct injury were admitted to our hospital. Their clinical data were analyzed retrospectively. RESULTS: Bile duct injury was caused by cholecys- tectomy in the eight cases, including seven cases with laparoscopic cholecystectomy and one with mini- incision choleystectomy. According to the classification of Strasberg, type E1 injury was found in one patient, type E2 injury in three, type E3 injury in two and type E4 injury in two patients. Both of the type E4 injury patients also had a vascular lesion of the hepatic artery. Six patients received Roux-en-Y hepaticojejunostomy for the second time, and one of them who had type E4 injury with the right hepatic artery disruption received right hepatectomy afterward. One patient who had type E4 injury with the proper hepatic artery lesion underwent liver transplantation, and the remaining one with type E3 injury received external biliary drainage. All the patients recovered fairly well postoperatively. CONCLUSION: Roux-en-Y hepaticojejunostomy is still the main approach for such failed surgical cases with bile duct injury. Special attention should be paid to concomitant vascular injury in these cases. The optimal timing and meticulous and excellent skills are essential to the success in this surgery.

关键词： Bile duct injury Biliary stricture Roux-en-Y hepaticojejunostomy Hepatic artery injury

Solution to the Dirac equation using the finite difference method

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Nuclear Science and Techniques 2020年第2期31卷 20-27页

作者： ji-Yu Fang Shou-Wan chen Tai-Hua Heng School of Physics and Materials Science Anhui University

In this study,single-particle energy was examined using the finite difference method by taking 208Pb as an *** the first derivative term in the spherical Dirac equation is discretized using a three-point formula,a one-to-one correspondence occurs between the physical and spurious *** these energies are exactly the same,the wave functions of the spurious states exhibit a much faster staggering than those of the physical *** spurious states can be eliminated when applying the finite difference method by introducing an extra Wilson term into the ***,it was also found that the number of spurious states can be reduced if we improve the accuracy of the numerical differential *** Dirac equation is then solved in a momentum space in which there is no differential operator,and we found that the spurious states can be completely avoided in the momentum space,even without an extra Wilson term.

关键词： Finite difference method Spurious states Momentum space

X-ray elastic constant determination and residual stress of two phase TiAl-based intermetallic alloy

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中国有色金属学会会刊：英文版 2001年第2期11卷 205-209页

作者：郭富安张永刚陈昌麒 ZHANG Yong-gong chen Chang-qi Department of Materials Science and Engineering Beijing University of Aeronautics and AstronauticsLM3 ESA CNRS 8006 ENSAM 151 Bd. del'Hpital Paris 75013 France Department of Materials Science and Engineering Beijing University of Aeronautics and Astronautics LM3 ESA CNRS 8006 ENSAM 151 Bd. del'Hpital Paris 75013 France

To evaluate the residual stress in TiAl based alloys by X ray diffraction, X ray elastic constants (REC) of a γ TiAl alloy were determined. From these results, the stress state of a given phase in a duplex TiAl based alloy under a uniaxial tensile loading has been characterized by X ray diffraction. The results show that the X ray elastic constants and the microscopic stresses of the given phase are different from the apparent elastic constants and the macroscopic stresses of the alloy. The reason of the different distribution of the alloy was also discussed. [

关键词： TiAl based alloy X ray diffraction technique X ray elastic constant duplex structure residual stress

Measurement factors of pollutants inside vehicle

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Journal of Environmental Science and Engineering 2008年第1期2卷 41-45页

作者： DENG Da-yue chen Shuang-ji Research Institute of Indoor Environment Beijing Union University Beijing 100083 China

The air quality inside vehicle is concerned widely in the world. The pollution inside vehicle is special serious in China. State Environmental Protection Administration of China is formulating the standard of air quality inside vehicle. However the measurement relates to many factors. Because of the small space, temperature easy changed, various ventilation modes, being close to pollution source of engine exhaust, there are differences between in-vehicle and indoor measurement. The influence of measuring factors was investigated. Those factors include temperature, preconditioning time, ventilation modes, engine state, and sampling fashion. The measuring mode and relating factors were discussed. The suggestion was offered.

关键词： air quality inside vehicle measurement method

黄酮类化合物对PRV感染小鼠的保护作用研究

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黑龙江畜牧兽医 2024年第17期 91-95,115-117页

作者：黄琨李振民吴昌旭冀禹彤陈心瑜张金武韦英益胡庭俊卢广元于美玲广西大学动物科学技术学院南宁530004 河池市巴马县那社乡水产畜牧兽医站广西马县547508

为了明确黄酮类化合物(槲皮素、木犀草素和山奈酚)对感染猪伪狂犬病病毒(Pseudorabies virus,PRV)小鼠的保护作用,试验将60只昆明小鼠随机分为6组(对照组、PRV组和4个药物组),每组10只(雌雄各半),除对照组外,其余组小鼠肌肉注射1×10^(2... 详细信息

为了明确黄酮类化合物(槲皮素、木犀草素和山奈酚)对感染猪伪狂犬病病毒(Pseudorabies virus,PRV)小鼠的保护作用,试验将60只昆明小鼠随机分为6组(对照组、PRV组和4个药物组),每组10只(雌雄各半),除对照组外,其余组小鼠肌肉注射1×10^(2)TCID_(50)PRV,100μL/只;感染后1小时灌胃给药,药物组小鼠分别按体重灌胃100 mg/kg槲皮素、木犀草素、山奈酚或阿昔洛韦,对照组和PRV组小鼠灌胃给予生理盐水,0.3 mL/只,连续给药7 d。试验期间,观察小鼠临床症状,统计小鼠死亡率,观察小鼠脏器组织病理学变化,并于试验第7天或小鼠濒死时采血,测定血清肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)的含量,评价槲皮素、木犀草素和山奈酚对感染PRV小鼠的保护作用。结果表明:黄酮类化合物有效缓解了PRV感染导致的小鼠抓挠、啃咬皮肤和被毛脱落、皮肤破损等临床症状;PRV组小鼠存活率为20%,槲皮素、山奈酚、木犀草素和阿昔洛韦组小鼠存活率分别为40%、60%、50%和60%,均显著高于PRV组(P<0.05);黄酮类化合物有效减轻了感染PRV小鼠的各器官水肿、充血、出血和细胞坏死等病理损伤;与PRV组相比,槲皮素组和阿昔洛韦组血清中TNF-α和IL-6含量极显著升高(P<0.01),木犀草素组和山奈酚组血清中TNF-α和IL-6含量显著升高(P<0.05)。说明黄酮类化合物(槲皮素、木犀草素和山奈酚)能通过提高血清中炎症因子水平增强小鼠免疫功能,减轻感染PRV小鼠的临床症状和病理损伤,并提高小鼠的存活率,发挥抗PRV感染的作用。

关键词：伪狂犬病病毒黄酮类化合物槲皮素木犀草素山奈酚保护作用

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四川省某露天矿石灰岩质高陡边坡稳定性分析

矿产勘查 2024年第S1期15卷 249-255页

作者：王一帆邹进吉豫庆陈恒宇张开选张世佳中安国泰(北京)科技发展有限公司北京101318 昆明坤泽矿业技术有限责任公司云南昆明650000 昭通市鼎安科技有限公司云南昭通657000

为研究高陡露天边坡的稳定性,本文以四川省某露天矿石灰岩质边坡为工程背景,选取1个典型剖面分析,运用赤平投影分析法对岩质边坡的稳定性进行分析评价,并采用强度理论的刚体极限平衡法与二维有限元数值模拟、三维数值模拟等进行了相互... 详细信息

为研究高陡露天边坡的稳定性,本文以四川省某露天矿石灰岩质边坡为工程背景,选取1个典型剖面分析,运用赤平投影分析法对岩质边坡的稳定性进行分析评价,并采用强度理论的刚体极限平衡法与二维有限元数值模拟、三维数值模拟等进行了相互验证比较分析。研究结果表明:1个典型剖面在3种工况下的整体边坡安全系数均符合规范要求值,边坡整体稳定性较好。所得结论对后期施工设计提供了理论依据及数据支持,同时为类似工程的边坡稳定性分析提供了参考。

关键词：高陡边坡赤平投影分析法刚体极限平衡法有限元稳定性分析

Graded composition and doping p-i-n Al_(x)Ga_(1−x)As/GaAs detector for unbiased voltage operation

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Nuclear Science and Techniques 2022年第7期33卷 73-82页

作者： Zhi-Fu Zhu ji-Jun Zou Zhi-jia Sun He Huang Qing-Lei Xiu Zhong-Ming Zhang Yong Gan chen-Xian Guo Shao-Tang Wang Xiu-Ping Yue Guo-Li Kong School of Information Engineering Zhengzhou University of TechnologyZhengzhou450044China Engineering Research Center of Nuclear Technology Application(East China University of Technology) Ministry of EducationNanchang330013China State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing100049China Engineering Department LA14YWLancaster UniversityLancasterUK

p-i-n Al_(x)Ga_(1−x)As/GaAs detectors with graded compositions and graded doping were grown and *** the current-voltage and capacitance-voltage measurement results,the devices had good p-n junction diode characteristics,and the electric field strength under an unbiased voltage was 1.7×10^(5) Vcm^(-1).The full width at half maximum and charge collection efficiency of the detectors obtained from energy spectrum measurements of 5.48-MeV alpha particles were 3.04 and approximately 93%,*** this study,we created the most advanced and promising state-of-the-art unbiased detector reported to date.

关键词： Graded composition Graded doping Detector p-i-n Al_(x)Ga_(1−x)As/GaAs