Cu-4.7%Sn （mass fraction） alloy plate was prepared by the self-developed two-phase zone continuous casting （TZCC） process. The relationship between process parameters of TZCC and surface quality of the alloy plate...Cu-4.7%Sn （mass fraction） alloy plate was prepared by the self-developed two-phase zone continuous casting （TZCC） process. The relationship between process parameters of TZCC and surface quality of the alloy plate was investigated. The microstructure and mechanical properties of the TZCC alloy plate were analyzed. The results show that Cu-4.7%Sn alloy plate with smooth surface can be obtained by means of reasonable matching the entrance temperature of two-phase zone mold and the continuous casting speed. The microstructure of the TZCC alloy is composed of grains-covered grains, small grains with self-closed grain boundaries, columnar grains and equiaxed grains. Compared with cold mold continuous casting Cu-4.7%Sn alloy plate, the room temperature tensile strength and ductility of the TZCC alloy plate are greatly improved.展开更多
Background:Most of previous studies aimed to estimate the effect of nurse staffing on quality of acute hospital care have used stochastic methods and their results are mixed.Objective:To measure the magnitude of effec...Background:Most of previous studies aimed to estimate the effect of nurse staffing on quality of acute hospital care have used stochastic methods and their results are mixed.Objective:To measure the magnitude of effect of nurse-staffing level on increasing quality of acute care services in long-run.Data:The number of practicing nurses'density per 1000 population as the proxy of nurse-staffing level and three Health Care Quality Indicators(HCQI)included 30-day mortality per 100 patients based on acute myocardial infarction(MORTAMIO),hemorrhagic stroke(MORTHSTO)and ischemic stroke(MORTISTO)were collected as a part of ongoing project by OECD.org in panels of 26 OECD countries over 2005-2015 period.Method:Panel data analysis.Results:There were committed relationships from nurse-staffing level to the enhancement of HCQI i.e.1%increase in nurse-staffing level would reduce the rates of patient mortality based on MORTAMIO,MORTHSTO and MORTISTO by 0.65%,0.60%and 0.80%,respectively.Furthermore,the role of nursestaffing level in increasing overall HCQI were simulated at the highest level in Sweden(-3.53),Denmark(-3.31),Canada(-2.59),Netherlands(-2.33),Finland(-2.09),Switzerland(-1.72),Australia(-1.64)and United States(-1.53).Conclusion:A higher proportion of nurses-staffing level is associated with higher quality of acute care services in OECD countries.Also,the nursing characteristics of Sweden,Denmark,Canada,Netherlands,Finland,Switzerland,Australia and United States would be good patterns for other countries to maximize nursing outcomes in the care of patients with acute and life-threatening conditions by reducing the risk of complication,mortality and adverse clinical outcomes.展开更多
In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with ...In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with the focus on flat-grinding. It is also going to present the method of choosing grinding wheels and parameters, as well as their impact on the processing quality parameters （roughness, surface flatness and seat width）. The optimization of the grinding process ensures acceptable quality of the final product applying the smallest possible changes in parameters at non-uniform quality levels of the tools. Here we have to make sure that the machining process is acceptable in terms of processing cost as weIl. We are going to use the G-factor as the efficiency indicator for different tools.展开更多
Time, cost, and quality are three key control factors in rockfill dam construction, and the tradeoff among them is important. Research has focused on the construction time-cost-quality tradeoff for the planning or des...Time, cost, and quality are three key control factors in rockfill dam construction, and the tradeoff among them is important. Research has focused on the construction time-cost-quality tradeoff for the planning or design phase, built on static empirical data. However, due to its intrinsic uncertainties, rockfill dam construction is a dynamic process which requires the tradeoffto adjust dynamically to changes in construction conditions. In this study, a dynamic time-cost-quality tradeoff （DTCQT） method is proposed to balance time, cost, and quality at any stage of the construction process. A time-cost-quality tradeoff model is established that considers time cost and quality cost. Time, cost, and quality are dynamically estimated based on real-time monitoring. The analytic hierarchy process （AHP） method is applied to quantify the decision preferences among time, cost, and quality as objective weights. In addition, an improved non-dominated sorting genetic algorithm （NSGA-II） coupled with the technique for order preference by similarity to ideal solution （TOPSIS） method is used to search for the optimal compromise solution. A case study project is analyzed to demonstrate the applicability of the method, and the efficiency of the proposed optimization method is compared with that of the linear weighted sum （LWS） and NSGA-II.展开更多
基金Project(51374025) supported by the National Natural Science Foundation of ChinaProject(2014Z-05) supported by the State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,ChinaProject(2152020) supported by the Beijing Natural Science Foundation,China
文摘Cu-4.7%Sn （mass fraction） alloy plate was prepared by the self-developed two-phase zone continuous casting （TZCC） process. The relationship between process parameters of TZCC and surface quality of the alloy plate was investigated. The microstructure and mechanical properties of the TZCC alloy plate were analyzed. The results show that Cu-4.7%Sn alloy plate with smooth surface can be obtained by means of reasonable matching the entrance temperature of two-phase zone mold and the continuous casting speed. The microstructure of the TZCC alloy is composed of grains-covered grains, small grains with self-closed grain boundaries, columnar grains and equiaxed grains. Compared with cold mold continuous casting Cu-4.7%Sn alloy plate, the room temperature tensile strength and ductility of the TZCC alloy plate are greatly improved.
文摘Background:Most of previous studies aimed to estimate the effect of nurse staffing on quality of acute hospital care have used stochastic methods and their results are mixed.Objective:To measure the magnitude of effect of nurse-staffing level on increasing quality of acute care services in long-run.Data:The number of practicing nurses'density per 1000 population as the proxy of nurse-staffing level and three Health Care Quality Indicators(HCQI)included 30-day mortality per 100 patients based on acute myocardial infarction(MORTAMIO),hemorrhagic stroke(MORTHSTO)and ischemic stroke(MORTISTO)were collected as a part of ongoing project by OECD.org in panels of 26 OECD countries over 2005-2015 period.Method:Panel data analysis.Results:There were committed relationships from nurse-staffing level to the enhancement of HCQI i.e.1%increase in nurse-staffing level would reduce the rates of patient mortality based on MORTAMIO,MORTHSTO and MORTISTO by 0.65%,0.60%and 0.80%,respectively.Furthermore,the role of nursestaffing level in increasing overall HCQI were simulated at the highest level in Sweden(-3.53),Denmark(-3.31),Canada(-2.59),Netherlands(-2.33),Finland(-2.09),Switzerland(-1.72),Australia(-1.64)and United States(-1.53).Conclusion:A higher proportion of nurses-staffing level is associated with higher quality of acute care services in OECD countries.Also,the nursing characteristics of Sweden,Denmark,Canada,Netherlands,Finland,Switzerland,Australia and United States would be good patterns for other countries to maximize nursing outcomes in the care of patients with acute and life-threatening conditions by reducing the risk of complication,mortality and adverse clinical outcomes.
文摘In the optimization of the process of steel valve plate grinding, it is necessary to take into consideration different processing parameters. This paper is going to describe the production of a steel valve plate with the focus on flat-grinding. It is also going to present the method of choosing grinding wheels and parameters, as well as their impact on the processing quality parameters （roughness, surface flatness and seat width）. The optimization of the grinding process ensures acceptable quality of the final product applying the smallest possible changes in parameters at non-uniform quality levels of the tools. Here we have to make sure that the machining process is acceptable in terms of processing cost as weIl. We are going to use the G-factor as the efficiency indicator for different tools.
基金Project supported by the Innovative Research Groups of the National Natural Science Foundation of China （No. 51621092）, the National Basic Research Program （973 Program） of China （No. 2013CB035904）, and the Natural Science Foundation of China （No. 51439005）
文摘Time, cost, and quality are three key control factors in rockfill dam construction, and the tradeoff among them is important. Research has focused on the construction time-cost-quality tradeoff for the planning or design phase, built on static empirical data. However, due to its intrinsic uncertainties, rockfill dam construction is a dynamic process which requires the tradeoffto adjust dynamically to changes in construction conditions. In this study, a dynamic time-cost-quality tradeoff （DTCQT） method is proposed to balance time, cost, and quality at any stage of the construction process. A time-cost-quality tradeoff model is established that considers time cost and quality cost. Time, cost, and quality are dynamically estimated based on real-time monitoring. The analytic hierarchy process （AHP） method is applied to quantify the decision preferences among time, cost, and quality as objective weights. In addition, an improved non-dominated sorting genetic algorithm （NSGA-II） coupled with the technique for order preference by similarity to ideal solution （TOPSIS） method is used to search for the optimal compromise solution. A case study project is analyzed to demonstrate the applicability of the method, and the efficiency of the proposed optimization method is compared with that of the linear weighted sum （LWS） and NSGA-II.
