Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The ind...Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.展开更多
The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemen...The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemental mercury,divalent mercury and particulate-phase mercury.Many studies showed that mercury in Beijing's air was higher than the general level of mercury concentration in the atmosphere.Mercury emission sources were discussed.Industrial emissions,coal burning,vehicle exhaust emissions and waste incineration were thought to be the main sources of atmospheric mercury pollution in Beijing.And also meteorology has an effect on atmospheric mercury concentration in Beijing.Measures have been taken to control the emission of mercury into the air in recent years.展开更多
English majors＇ B.A. （Bachelor of Arts） thesis writing is an important part and test of the students＇ four-year undergraduate education. It lays solid foundation for their future study and work. Yet serious proble...English majors＇ B.A. （Bachelor of Arts） thesis writing is an important part and test of the students＇ four-year undergraduate education. It lays solid foundation for their future study and work. Yet serious problems exist during the process. The author of the paper collects and analyzes the 289 titles of English majors＇ B.A. writing in the recent two years in Changchun University, China. The results of the analysis reveal that almost 40% of the titles are on literature every year and among them there are some similar titles. In view of this situation, the author first explores the reasons that caused those problems. One of the important reasons is that the increasing of the supervisors and reference materials cannot keep the pace of the expanding of students＇ numbers. The author, after that, makes some reflections on those problems, then proposes five practical supervising strategies, and makes some relevant suggestions for English major＇s thesis writing. Meanwhile some other related problems in thesis writing in China are also discussed.展开更多
The development of the logistics work is one of the indispensable important components in the whole construction and development process of colleges and universities. The effective development of the logistics work ca...The development of the logistics work is one of the indispensable important components in the whole construction and development process of colleges and universities. The effective development of the logistics work can lay a solid, powerful foundation for the implementation of the main functions and the education and teaching activities, and also can provide a reliable guarantee for the teaching management work. Therefore, the important significance and value of the logistics management work in colleges and universities are seen. According to the actual situation, in this paper, the logistics work in colleges and universities is deeply considered and discussed, and the main problems in the present logistics management are studied based on fully understanding the logistics management specialties, and then the measures and methods for solving the above problems are proposed. Hopefully, a due effect is played on the quality of the logistics management in colleges and universities at the present time.展开更多
文摘Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.
文摘The atmospheric mercury pollution in Beijing is a serious problem.Atmospheric mercury has three sources:natural emission,anthropogenic emission and previously deposited mercury reemission or recycling,composing elemental mercury,divalent mercury and particulate-phase mercury.Many studies showed that mercury in Beijing's air was higher than the general level of mercury concentration in the atmosphere.Mercury emission sources were discussed.Industrial emissions,coal burning,vehicle exhaust emissions and waste incineration were thought to be the main sources of atmospheric mercury pollution in Beijing.And also meteorology has an effect on atmospheric mercury concentration in Beijing.Measures have been taken to control the emission of mercury into the air in recent years.
文摘English majors＇ B.A. （Bachelor of Arts） thesis writing is an important part and test of the students＇ four-year undergraduate education. It lays solid foundation for their future study and work. Yet serious problems exist during the process. The author of the paper collects and analyzes the 289 titles of English majors＇ B.A. writing in the recent two years in Changchun University, China. The results of the analysis reveal that almost 40% of the titles are on literature every year and among them there are some similar titles. In view of this situation, the author first explores the reasons that caused those problems. One of the important reasons is that the increasing of the supervisors and reference materials cannot keep the pace of the expanding of students＇ numbers. The author, after that, makes some reflections on those problems, then proposes five practical supervising strategies, and makes some relevant suggestions for English major＇s thesis writing. Meanwhile some other related problems in thesis writing in China are also discussed.
文摘The development of the logistics work is one of the indispensable important components in the whole construction and development process of colleges and universities. The effective development of the logistics work can lay a solid, powerful foundation for the implementation of the main functions and the education and teaching activities, and also can provide a reliable guarantee for the teaching management work. Therefore, the important significance and value of the logistics management work in colleges and universities are seen. According to the actual situation, in this paper, the logistics work in colleges and universities is deeply considered and discussed, and the main problems in the present logistics management are studied based on fully understanding the logistics management specialties, and then the measures and methods for solving the above problems are proposed. Hopefully, a due effect is played on the quality of the logistics management in colleges and universities at the present time.
