在Anton Paar DMA 4500M数字密度计测定正丙醇-三乙酸甘油酯、正丁醇-三乙酸甘油酯以及正丁醇-乙酸丁酯二元混合体系在常压、温度为(293.15~328.15K)下的密度.利用该实验密度计算直链醇与酯类在不同温度(293.15~328.15K)下混合体系的超...在Anton Paar DMA 4500M数字密度计测定正丙醇-三乙酸甘油酯、正丁醇-三乙酸甘油酯以及正丁醇-乙酸丁酯二元混合体系在常压、温度为(293.15~328.15K)下的密度.利用该实验密度计算直链醇与酯类在不同温度(293.15~328.15K)下混合体系的超额摩尔体积。利用R-K多项式方程对混合体系的超额摩尔体积与组分浓度关系进行关联.结果发现,不同浓度下正丙醇-三乙酸甘油酯、正丁醇-三乙酸甘油酯以及正丁醇-乙酸丁酯二元混合体系的超额摩尔体积均呈正偏差,且正偏差程度随温度的升高而增大。研究表明,极性有机混合体系分子间存在互缔合与自缔合的相互竞争,碳链与支链增加使得分子空间阻隔作用和溶质溶剂化效应增强。展开更多
A nonlinear seismic analysis method for complex frame structures subjected to sta- tionary random ground excitations is proposed.The nonlinear elasto-plastic behaviors may take place only on a small part of the struct...A nonlinear seismic analysis method for complex frame structures subjected to sta- tionary random ground excitations is proposed.The nonlinear elasto-plastic behaviors may take place only on a small part of the structure.The Bouc-Wen differential equation model is used to model the hysteretic characteristics of the nonlinear components.The Pseudo Excitation Method (PEM)is used in solving the linearized random differential equations to replace the solution of the less efficient Lyapunov equation.Numerical results of a real bridge show that the method proposed is effective for practical engineering analysis.展开更多
In recent years, China's social and economic development has advanced by leaps and bounds, and water conservancy has also been greatly developed. Under the current situation, the scale of water conservancy and hyd...In recent years, China's social and economic development has advanced by leaps and bounds, and water conservancy has also been greatly developed. Under the current situation, the scale of water conservancy and hydropower projects in China is constantly expanding, and it is playing an increasingly important role in agriculture, shipping and hydropower generation. Slope construction is an important part of water conservancy and hydropower projects, and the quality of slope construction directly affects the overall construction level of water conservancy and hydropower projects. However, it is worth noting that there are still some shortcomings in the slope construction of water conservancy and hydropower projects in China at this stage. Some construction units have weak sense of responsibility, and pay low attention to the slope construction, so they cannot strengthen their management. In this case, the slope construction quality of water conservancy and hydropower projects is difficult to be guaranteed, which has a great impact on the subsequent use of water conservancy and hydropower projects, and poses a certain threat to the lives and property safety of people around the project. In this paper, the slope excavation technology and supporting technology in water conservancy and hydropower projects are studied in detail, and some suggestions are put forward, in order to help the construction unit to strengthen the control of the slope construction quality of water conservancy and hydropower projects and improve the slope construction level.展开更多
At present, according to the characteristics of the medical industry, research is carried out on the work of safety in production in hospitals, and the shortcomings and blind spots in safety management are analyzed. C...At present, according to the characteristics of the medical industry, research is carried out on the work of safety in production in hospitals, and the shortcomings and blind spots in safety management are analyzed. Combined with the construction of risk classification and hidden danger investigation and management system, the risks of safety in production are comprehensively sorted out. In medical institutions, risk assessment and hierarchical control are carried out for the risks of public logistic support facilities such as fire fighting, water supply and heating, and power supply in hospitals, so as to strengthen the investigation and management of potential safety hazards, implement the management and prevention, improve the safety management level of hospitals, and avoid production safety accidents. It does not include the prevention and control of medical accidents and their risks.展开更多
The Moving Pictures Expert Group(MPEG)and H.263 standard codingmethod is widely used in video compression. However, the visualquality of detail regions such as eyes and mouth is not content inpeople at the decoder, as...The Moving Pictures Expert Group(MPEG)and H.263 standard codingmethod is widely used in video compression. However, the visualquality of detail regions such as eyes and mouth is not content inpeople at the decoder, as far as the conference telephone orvideophone is concerned. A new coding method based on improving de-tail regions is presented in this paper. Experimental results showthat this method can improve the visual quality at the decoder.展开更多
文摘在Anton Paar DMA 4500M数字密度计测定正丙醇-三乙酸甘油酯、正丁醇-三乙酸甘油酯以及正丁醇-乙酸丁酯二元混合体系在常压、温度为(293.15~328.15K)下的密度.利用该实验密度计算直链醇与酯类在不同温度(293.15~328.15K)下混合体系的超额摩尔体积。利用R-K多项式方程对混合体系的超额摩尔体积与组分浓度关系进行关联.结果发现,不同浓度下正丙醇-三乙酸甘油酯、正丁醇-三乙酸甘油酯以及正丁醇-乙酸丁酯二元混合体系的超额摩尔体积均呈正偏差,且正偏差程度随温度的升高而增大。研究表明,极性有机混合体系分子间存在互缔合与自缔合的相互竞争,碳链与支链增加使得分子空间阻隔作用和溶质溶剂化效应增强。
基金Project supported by the National Natural Science Foundation of China(No.10072015)the National Key Base Research Special Foundation(No.G1999032805).
文摘A nonlinear seismic analysis method for complex frame structures subjected to sta- tionary random ground excitations is proposed.The nonlinear elasto-plastic behaviors may take place only on a small part of the structure.The Bouc-Wen differential equation model is used to model the hysteretic characteristics of the nonlinear components.The Pseudo Excitation Method (PEM)is used in solving the linearized random differential equations to replace the solution of the less efficient Lyapunov equation.Numerical results of a real bridge show that the method proposed is effective for practical engineering analysis.
文摘In recent years, China's social and economic development has advanced by leaps and bounds, and water conservancy has also been greatly developed. Under the current situation, the scale of water conservancy and hydropower projects in China is constantly expanding, and it is playing an increasingly important role in agriculture, shipping and hydropower generation. Slope construction is an important part of water conservancy and hydropower projects, and the quality of slope construction directly affects the overall construction level of water conservancy and hydropower projects. However, it is worth noting that there are still some shortcomings in the slope construction of water conservancy and hydropower projects in China at this stage. Some construction units have weak sense of responsibility, and pay low attention to the slope construction, so they cannot strengthen their management. In this case, the slope construction quality of water conservancy and hydropower projects is difficult to be guaranteed, which has a great impact on the subsequent use of water conservancy and hydropower projects, and poses a certain threat to the lives and property safety of people around the project. In this paper, the slope excavation technology and supporting technology in water conservancy and hydropower projects are studied in detail, and some suggestions are put forward, in order to help the construction unit to strengthen the control of the slope construction quality of water conservancy and hydropower projects and improve the slope construction level.
文摘At present, according to the characteristics of the medical industry, research is carried out on the work of safety in production in hospitals, and the shortcomings and blind spots in safety management are analyzed. Combined with the construction of risk classification and hidden danger investigation and management system, the risks of safety in production are comprehensively sorted out. In medical institutions, risk assessment and hierarchical control are carried out for the risks of public logistic support facilities such as fire fighting, water supply and heating, and power supply in hospitals, so as to strengthen the investigation and management of potential safety hazards, implement the management and prevention, improve the safety management level of hospitals, and avoid production safety accidents. It does not include the prevention and control of medical accidents and their risks.
文摘The Moving Pictures Expert Group(MPEG)and H.263 standard codingmethod is widely used in video compression. However, the visualquality of detail regions such as eyes and mouth is not content inpeople at the decoder, as far as the conference telephone orvideophone is concerned. A new coding method based on improving de-tail regions is presented in this paper. Experimental results showthat this method can improve the visual quality at the decoder.
