Computer simulation was used for optimizing a hot zone for Czochralski （CZ） silicon crystal growth. The heater structure and heat shield material were investigated. With this optimized hot zone, the temperature grad...Computer simulation was used for optimizing a hot zone for Czochralski （CZ） silicon crystal growth. The heater structure and heat shield material were investigated. With this optimized hot zone, the temperature gradient near the crystal/melt interface increased and the CZ crystal could be grown at a faster rate. It is a great contribution for saving power consumption.展开更多
Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42%were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law.A sim...Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42%were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law.A simple predicting method for crack growth rates has been proposed involving strengthσband the relation between cyclic stress and strain.The validity of proposed method has been confirmed by experiments on several carbon steels with different loadings.展开更多
Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the s...Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.展开更多
The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent...The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.展开更多
为准确把握城市轨道交通客流生成规律,本文从客流成长性视角探究城市轨道交通站点客流与站点周边建成环境之间的交互关系。以上海市城市轨道交通为研究案例,通过人口及就业密度、土地利用、路网密度、出入口数量、介中心性等13个因子刻...为准确把握城市轨道交通客流生成规律,本文从客流成长性视角探究城市轨道交通站点客流与站点周边建成环境之间的交互关系。以上海市城市轨道交通为研究案例,通过人口及就业密度、土地利用、路网密度、出入口数量、介中心性等13个因子刻画建成环境,基于上海市地铁刷卡数据、人口及经济普查、兴趣点(Point of Interest,POI)、道路网络等多源异构数据,分别构建建成环境对轨道交通客流影响的普通最小二乘法(Ordinary Least Square,OLS)模型与极限梯度提升(eXtreme Gradient Boosting,XGBoost)模型进行量化实证分析。结果表明,基于机器学习算法的XGBoost模型比OLS模型具有更好的模型表现。从影响贡献度来看,轨道交通站点建成初期,地铁站点出入口数量(21.9%),常住人口密度(15.9%),路网密度(9.8%)是影响城市轨道交通站点客流的最重要建成环境因素。建成近期,商业设施用地(16.5%)、容积率(11.1%)和就业密度(8.5%)等用地类建成环境变量成为提升城市轨道交通站点客流的关键。建成远期,城市轨道交通站点客流水平取决于出入口数量(18.9%)、商业设施用地开发(16.6%)与换乘线路数量(7.7%)等用地和交通之间的结合水平。研究结果证实了轨道交通客流与站点周边建成环境之间的成长性特征关系及各阶段显著影响客流的建成环境变量,为因时制宜制定城市轨道交通站城一体化开发策略提供了参考。展开更多
BACKGROUND Clinically significant portal hypertension(CSPH) and severe portal hypertension(SPH) increase the risk for decompensation and life-threatening complications in liver cirrhosis. Pathologic angiogenesis might...BACKGROUND Clinically significant portal hypertension(CSPH) and severe portal hypertension(SPH) increase the risk for decompensation and life-threatening complications in liver cirrhosis. Pathologic angiogenesis might contribute to the formation of these conditions. Placental growth factor(PlGF) and Nogo-A protein are biomarkers of pathological angiogenesis, but data on their role in liver cirrhosis and portal hypertension is scarce.AIM To determine plasma levels of PlGF and Nogo-A in patients with liver cirrhosis,CSPH, SPH and potential to predict portal hypertension.METHODS A cohort of 122 patients with hepatitis C virus and/or alcohol-induced liver cirrhosis with characterized hepatic venous pressure gradient(HVPG) were included in the study. Demographic data, medical history, Child-Turcotte-Pugh and Model of End Stage liver disease score, clinical chemistry, liver stiffnessvalues were recorded on the day of the procedure prior HVPG measurement. The degree of portal hypertension was determined by the invasive HVPG measurement. Nogo-A and PlGF plasma levels were evaluated using enzyme linked immunosorbent assay. The control group consisted of 30 healthy age-and sex-matched individuals.RESULTS Peripheral PlGF levels were higher and Nogo-A levels were lower in patients with liver cirrhosis(23.20 vs 9.85;P < 0.0001 and 2.19 vs 3.12;P = 0.004 respectively). There was a positive linear correlation between peripheral levels of PlGF and HVPG(r = 0.338, P = 0.001) and negative linear correlation between the peripheral Nogo-A levels and HVPG(r =-0.267, P = 0.007). PlGF levels were higher in CSPH and SPH(P = 0.006;P < 0.0001) whereas Nogo-A levels were lower(P = 0.01;P < 0.033). Area under the curve for the diagnosis of CSPH for PlGF was 0.68(P = 0.003) and for Nogo-A-0.67(P = 0.01);for SPH 0.714(P <0.0001) and 0.65(P = 0.014) respectively. PlGF levels were higher and Nogo-A levels were lower in patients with esophageal varices(P < 0.05). PlGF cut-off value of 25 pg/mL distinguished patients with CSPH at 55.7% sensitivity and76.7% specificity;whereas Nogo-A cut-off value of 1.12 ng/mL was highly specific(93.1%) for the diagnosis of CSPH.CONCLUSION Plasma PlGF levels were higher while Nogo-A levels were lower in patients with liver cirrhosis and portal hypertension. Biomarkers showed moderate predictive value in determining CSPH and SPH.展开更多
文摘Computer simulation was used for optimizing a hot zone for Czochralski （CZ） silicon crystal growth. The heater structure and heat shield material were investigated. With this optimized hot zone, the temperature gradient near the crystal/melt interface increased and the CZ crystal could be grown at a faster rate. It is a great contribution for saving power consumption.
基金the supports from the Research Foundation for Visiting Scholars of Key Laboratory of Solid Mechanics and FML of Education Ministry,P R Chinathe supports from Japan Society for Promotion of Science
文摘Three types of fatigue tests for an annealed carbon steel containing carbon of 0.42%were carried out on smooth specimens and specimens with a small blind hole in order to investigate the fatigue crack growth law.A simple predicting method for crack growth rates has been proposed involving strengthσband the relation between cyclic stress and strain.The validity of proposed method has been confirmed by experiments on several carbon steels with different loadings.
文摘Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electro- lyte-suspension co-deposition. After submicron diamonds were added to the electrolyte, the shape of copper grains transformed from oval or round to polyhedron, the growth mode of copper grains transformed from columnar growth to gradual change in size, and the preferred ori- entation of copper grains transformed from （220） to （200）. Analyzing the variation of cathodic overpotential, it was found that the cathodic overpotential tended to remain tmchanged when copper plane （220） grew in the process of electrodepositing pure copper, while it tended to decrease with time when copper plane （200） grew in the process of co-deposition. It was inferred that copper plane （200） was propitious to the deposition of submicron diamonds.
文摘The current study performed a finite element analysis of the strain localization behavior of a voided ductile material using a non-local plasticity formulation in which the yield strength depends on both an equivalent plastic strain measurement (hardening parameter) and Laplacian equivalent. The introduction of gradient terms to the yield function was found to play an important role in simulating the strain localization behavior of the voided ductile material. The effect of the mesh size and characteristic length on the strain localization were also investigated. An FEM simulation based on the proposed non-local plasticity revealed that the load-strain curves of the voided ductile material subjected to plane strain tension converged to one curve, regardless of the mesh size. In addition, the results using non-local plasticity also exhibited that the dependence of the deformation behavior of the material on the mesh size was much less sensitive than that with classical local plasticity and could be successfully eliminated through the introduction of a large value for the characteristic length.
文摘为准确把握城市轨道交通客流生成规律,本文从客流成长性视角探究城市轨道交通站点客流与站点周边建成环境之间的交互关系。以上海市城市轨道交通为研究案例,通过人口及就业密度、土地利用、路网密度、出入口数量、介中心性等13个因子刻画建成环境,基于上海市地铁刷卡数据、人口及经济普查、兴趣点(Point of Interest,POI)、道路网络等多源异构数据,分别构建建成环境对轨道交通客流影响的普通最小二乘法(Ordinary Least Square,OLS)模型与极限梯度提升(eXtreme Gradient Boosting,XGBoost)模型进行量化实证分析。结果表明,基于机器学习算法的XGBoost模型比OLS模型具有更好的模型表现。从影响贡献度来看,轨道交通站点建成初期,地铁站点出入口数量(21.9%),常住人口密度(15.9%),路网密度(9.8%)是影响城市轨道交通站点客流的最重要建成环境因素。建成近期,商业设施用地(16.5%)、容积率(11.1%)和就业密度(8.5%)等用地类建成环境变量成为提升城市轨道交通站点客流的关键。建成远期,城市轨道交通站点客流水平取决于出入口数量(18.9%)、商业设施用地开发(16.6%)与换乘线路数量(7.7%)等用地和交通之间的结合水平。研究结果证实了轨道交通客流与站点周边建成环境之间的成长性特征关系及各阶段显著影响客流的建成环境变量,为因时制宜制定城市轨道交通站城一体化开发策略提供了参考。
基金Supported by the Research Fund of Lithuanian University of Health Sciences(SV5-074/BN17-99)No.LSMU-21
文摘BACKGROUND Clinically significant portal hypertension(CSPH) and severe portal hypertension(SPH) increase the risk for decompensation and life-threatening complications in liver cirrhosis. Pathologic angiogenesis might contribute to the formation of these conditions. Placental growth factor(PlGF) and Nogo-A protein are biomarkers of pathological angiogenesis, but data on their role in liver cirrhosis and portal hypertension is scarce.AIM To determine plasma levels of PlGF and Nogo-A in patients with liver cirrhosis,CSPH, SPH and potential to predict portal hypertension.METHODS A cohort of 122 patients with hepatitis C virus and/or alcohol-induced liver cirrhosis with characterized hepatic venous pressure gradient(HVPG) were included in the study. Demographic data, medical history, Child-Turcotte-Pugh and Model of End Stage liver disease score, clinical chemistry, liver stiffnessvalues were recorded on the day of the procedure prior HVPG measurement. The degree of portal hypertension was determined by the invasive HVPG measurement. Nogo-A and PlGF plasma levels were evaluated using enzyme linked immunosorbent assay. The control group consisted of 30 healthy age-and sex-matched individuals.RESULTS Peripheral PlGF levels were higher and Nogo-A levels were lower in patients with liver cirrhosis(23.20 vs 9.85;P < 0.0001 and 2.19 vs 3.12;P = 0.004 respectively). There was a positive linear correlation between peripheral levels of PlGF and HVPG(r = 0.338, P = 0.001) and negative linear correlation between the peripheral Nogo-A levels and HVPG(r =-0.267, P = 0.007). PlGF levels were higher in CSPH and SPH(P = 0.006;P < 0.0001) whereas Nogo-A levels were lower(P = 0.01;P < 0.033). Area under the curve for the diagnosis of CSPH for PlGF was 0.68(P = 0.003) and for Nogo-A-0.67(P = 0.01);for SPH 0.714(P <0.0001) and 0.65(P = 0.014) respectively. PlGF levels were higher and Nogo-A levels were lower in patients with esophageal varices(P < 0.05). PlGF cut-off value of 25 pg/mL distinguished patients with CSPH at 55.7% sensitivity and76.7% specificity;whereas Nogo-A cut-off value of 1.12 ng/mL was highly specific(93.1%) for the diagnosis of CSPH.CONCLUSION Plasma PlGF levels were higher while Nogo-A levels were lower in patients with liver cirrhosis and portal hypertension. Biomarkers showed moderate predictive value in determining CSPH and SPH.
