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Desulfurization of coal by an electrochemical-reduction flotation technique

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Journal of China University of Mining and Technology 2008年第4期18卷 571-574页

作者： zhao wei XU wen-juan ZHONG Shi-teng ZONG Zhi-min School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou Jiangsu 221116 China

The optimum conditions for sulfur removal from coal by electrochemical reduction flotation in an aqueous NaCl solution were determined from orthogonal experiments. The effect of electrolytic conditions on the desulfurization ratio was also studied. The electrochemical-reduction processed coal was examined by X-ray diffraction, Fourier transform infrared spectroscopy and wet chemical analysis. The results show that electrochemical reduction converts hydrophobic pyrite in Nantong coal into hydrophilic FeS and S2- and leads to an increase in the concentration of hydroxyl groups and aliphatic moieties and a corresponding decrease in carboxyl and carbonyl groups, which enhances the flotation desulfurization of the coal.

关键词： desulfurization coal electrolytic reduction flotation

Linear Integral Analysis of Bar Rough Rolling by Strain Rate Vector

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Journal of Iron and Steel Research International 2010年第3期17卷 28-33页

作者： DENG wei zhao De-wen QIN Xiao-mei GAO Xiu-hua DU Lin-xiu LIU Xiang-hua State Key Laboratory of Rolling and Automation Northeastern University Shenyang 110004 Liaoning China

A new linear integral method for bar hot rolling on roughing train was obtained. First, for plastic deformation energy rate, equivalent strain rate about Kobayashi＇s three-dimensional velocity field was expressed by two-dimensional strain rate vector; then, the two-dimensional strain rate vector was inverted into inner product and was integrated term by term. During those processes, boundary equation and mean value theorem were introduced; for friction and shear energy dissipation rate, definite integral was applied to the solution process. Sequentially, the total upper bound power was minimized, and the analytical expressions of rolling torque, separating force, and stress state factor were obtained. The calculated results by these expressions were compared with those of experimental values. The results show that the new linear integral method is available for bar rough rolling analysis and the calculated results by this method are a little higher than those of experimental ones. However, the maximum error between them is less than 10%.

关键词： bar rough rolling linear integration strain rate vector roll separating force

NUMERICAL SIMULATION AND ANALYSIS ON THE HEMODYNAMICS OF AN ELASTIC ANEURYSM

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Journal of Hydrodynamics 2008年第2期20卷 216-224页

作者： zhao Jun-wei YIN wen-yi DING Guang-hong YANG Xin-jian SHI Wan-chao ZHANG Xiao-long Department of Mechanics and Engineering Science Fudan University Shanghai 200433 China Beijing Institute ofNeurosurgery Beijing 100050 China Huashan Hospital Affiliated to Fudan University Shanghai 200040 China

Intracranial aneurysms are pathological dilatations which endanger people＇s health. Hemodynamics is thought to be an important factor in the pathogenesis and treatment of aneurysms. To date, the bulk of investigations into hemodynamics have been conducted by making use of mathematically idealized models for rigid aneurysms and associated arteries. However the walls of aneurysms and associated arteries are elastic in vivo. This study shows the differences of the simulation between elastic and rigid wall models. The numerical simulation of elastic aneurysm model is made fi＇om a representative Digital Subtraction Angiography （DSA） image and calculated with CFD software to get the wall deformation and the velocity field. Then the results are analyzed. By comparing the simulation results of the two models from their velocity vectors and shear stress distribution, many differences can be noted. The main difference exists in the distribution of velocity magnitude at some sections, with one outlet having obviously off-center distribution for the elastic wall model. The currents of the distribution of wall shear stress along the wall of aneurysm simulated in rigid and elastic wall models were similar. But there were apparent differences between the two models on the values of wall shear stress especially at the neck of aneurysm. The off-center distribution of velocity magnitude affects the distribution of wall shear stress and the exchange of substance through the wall. The analysis demonstrated clearly that the results of 2-D elastic numerical simulation were in good agreement with the clinical and pathological practice. The results of this study play an important role in the formation, growth, rupture and prognosis of an aneurysm on clinic application.

关键词： aneurysm 2-D numerical simulation elastic wall medical image

Analysis of post-operative endophthalmitis after pars plana vitrectomy： a 10-year experience at a single center

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Chinese Medical Journal 2013年第15期126卷 2890-2893页

作者： SHI Xiang-yu zhao Hong-shu wei wen-bin Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Laboratory Beijing 100730 China

Background Endophthalmitis can be a devastating complication after pars plana vitrectomy. The incidence of post- vitrectomy endophthalmitis is significantly lower than that of endophthalmitis occurring after other intraocular operations. However, normal post-operative pain and inflammation may mask endophthalmitis and lead to delayed diagnosis and grave visual consequences. This study aimed to summarize the outcomes of cases that underwent pars plana vitrectomy over a 10-year period and to analyze the characteristics of post-vitrectomy endophthalmitis. Methods A retrospective observational case study was conducted on all the cases who underwent pars plana vitrectomy in the Beijing Tongren Hospital between January 1, 2002 and March 31, 2012. All cases of endophthalmitis that occurred during a period of 10 years and 3 months were reviewed, and the possible risk factors, clinical findings, causative organism（s）, and the sources of infection were analyzed. Results Within the 10-year observational period, 14 patients developed endophthalmitis after pars plana vitrectomy. The incidence of post-vitrectomy endophthalmitis （0.05%） was lower than that reported previously from the same center （0.12%）. Staphylococcus epidermidis （five patients, 35.71%） was the most common organism identified in aqueous or vitreous cultures. Eight patients （57.14%） had diabetes mellitus. There was no statistically significant difference （P 〉0.05） in the incidence of endophthalmitis between period 1 （with antibiotic pretreatment） and period 2 （without antibiotic pretreatment）. Surgical procedures for the treatment of endophthalmitis were performed in 10 patients （71.43%）. Conclusions This series of cases showed that the incidence of endophthalmitis after pars plana vitrectomy is lower than what was previously reported in our hospital. A variable degree of corneal edema with relatively normal or mildly increased intraocular pressure was one of the commonly observed characteristics of post-vitrecto

关键词： pars plana vitrectomy endophthalmitis post-operative complication

A novel method to improve spatial resolution of acousto-optic deflector

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Optoelectronics Letters 2006年第1期2卷 34-36页

作者： wen Tao ZHUANG zhao-wen wei Ji-bo MA Dong-tang College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

In this paper, a novel method of laser beam deflecting is introduced to improve the spatial resolution of an acoustic-optic deflector (AOD). We use double AOD (DAOD) to control laser beam. Compared with single AOD, the double AOD can improve speed and precision of target tracking and pointing significantly. Finally, a method of calculating the static and dynamic number of resolvable points (NRP) is provided, and it is supported by the experimental data excellently.

关键词：光学偏转仪空间分辨率激光束靶点轨迹

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国内图书馆开展数字参考咨询服务的思考

情报科学 2005年第9期23卷 1364-1366,1402页

作者：赵文伟浙江财经学院图书馆浙江杭州310012

本文分析和探讨了目前国内图书馆开展数字参考咨询服务的指导思想和服务方式。

关键词：参考咨询数字参考咨询服务 DRS

关帝山不同海拔华北落叶松人工林土壤养分特征

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江西农业大学学报 2019年第6期41卷 1103-1112页

作者：赵伟文梁文俊魏曦山西农业大学林学院

了解不同海拔华北落叶松人工林土壤养分特征规律,为揭示土壤-海拔生态学功能具有重要作用。本文以山西吕梁关帝山自然保护区八道沟和柴禄沟落叶松人工林为研究对象,采用随机取样法取样,测定土壤总氮、有效钾、土壤有机质、有效磷、土壤... 详细信息

了解不同海拔华北落叶松人工林土壤养分特征规律,为揭示土壤-海拔生态学功能具有重要作用。本文以山西吕梁关帝山自然保护区八道沟和柴禄沟落叶松人工林为研究对象,采用随机取样法取样,测定土壤总氮、有效钾、土壤有机质、有效磷、土壤总磷和铵态氮含量,分析土壤养分水平和垂直空间变异性。结果表明:(1)关帝山八道沟、柴禄沟土壤有机质含量分别为77.38 g/kg、55.38 g/kg,两区域有机质含量充沛,其余土壤各养分含量也相对较高。(2)通过半方差函数分析两区域土壤养分,得出除柴禄沟土壤有机质含量拟合程度不高外,两区域的土壤其余养分拟合模型理想,八道沟土壤总氮和有机质含量空间变异小于柴禄沟。(3)分析两区域典型林分的土壤养分空间分布图可知,两区域土壤各养分含量表现为在东北方向上占绝对优势。八道沟土壤各养分空间分布较为复杂。(4)根据土壤各类养分含量Pearson相关性分析发现,土壤养分两两之间存在相关性,具有协同效应。土壤有机质与有效钾呈极显著负相关,土壤有效磷与土壤铵态氮呈极显著负相关性。(5)对土壤养分含量随海拔梯度变化分析可知,土壤养分含量大体上均随海拔梯度的增加而增加,土壤铵态氮含量与土壤总氮和有机质含量随海拔梯度变化趋势相同。

关键词：华北落叶松海拔土壤养分空间变异

用大涡模拟方法数值模拟Spar平台涡激运动问题

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水动力学研究与进展（A辑） 2015年第1期30卷 40-46页

作者：赵伟文万德成上海交通大学船舶海洋与建筑工程学院海洋工程国家重点实验室高新船舶与深海开发装备协同创新中心上海200240

该文采用基于开源代码计算流体力学工具包Open FOAM开发的船舶与海洋工程水动力学求解器naoeFOAM-SJTU,对一座Spar模型的硬舱部分进行了涡激运动的数值模拟。采用大涡模拟方法数值模拟了不同折合速度下Spar模型的涡激运动情况,并与Finni... 详细信息

该文采用基于开源代码计算流体力学工具包Open FOAM开发的船舶与海洋工程水动力学求解器naoeFOAM-SJTU,对一座Spar模型的硬舱部分进行了涡激运动的数值模拟。采用大涡模拟方法数值模拟了不同折合速度下Spar模型的涡激运动情况,并与Finnigan等[1,2]的模型试验结果作了对比和分析,证明了求解器naoe-FOAM-SJTU在模拟涡激运动方面的可靠性。

关键词： Spar平台涡激运动折合速度大涡模拟 naoe-FOAM-SJTU求解器

用SST-DES和SST-URANS方法数值模拟亚临界雷诺数下三维圆柱绕流问题

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水动力学研究与进展（A辑） 2016年第1期31卷 1-8页

作者：赵伟文万德成上海交通大学船舶海洋与建筑工程学院海洋工程国家重点实验室高新船舶与深海开发装备协同创新中心上海200240

基于剪切应力运输(shear stress transport,SST)的分离涡模拟(detached-eddy simulation,DES)在近壁面的流动区域采用SST模型,而在其他区域采用亚格子模型求解流场。本研究中分别应用SST-DES和SST-URANS方法对亚临界雷诺数Re=3900下的... 详细信息

基于剪切应力运输(shear stress transport,SST)的分离涡模拟(detached-eddy simulation,DES)在近壁面的流动区域采用SST模型,而在其他区域采用亚格子模型求解流场。本研究中分别应用SST-DES和SST-URANS方法对亚临界雷诺数Re=3900下的三维圆柱绕流进行了数值模拟,比较分析了两种数值方法下圆柱表面的时均压力分布、圆柱后方的漩涡脱落特征、圆柱下游流场的时均速度剖面分布等,并将数值模拟结果同前人物理试验比较,结果表明SST-DES方法在亚临界雷诺数下的三维圆柱绕流数值模拟问题上比SST-RANS方法具有更好的效果。

关键词：圆柱绕流流动分离分离涡模拟亚临界雷诺数