Gas injection process is a very important technology in enhanced oil recovery.Minimum miscible pressure is one of the key parameters in gas injection processes.Various experimental methods such as slim tube are used t...Gas injection process is a very important technology in enhanced oil recovery.Minimum miscible pressure is one of the key parameters in gas injection processes.Various experimental methods such as slim tube are used to measure MMP.These methods are costly and time consuming.Recently computational methods are used in order to achieve a cost-effective and reliable technique to evaluate MMP.In this work,a new methodology has been proposed for determination of MMP using the minimum tie line length method.A real mixing cell model was developed to estimate the MMP,MME and key tie lines.This method is simple,robust,and faster than conventional one-dimensional simulation of slim tube.The new mixing cells method can accurately determine the whole key tie lines to a shift,regardless of the number of injection gas and reservoir fluid components.Unlike other methods of mixing cells,this method automatically corrects dispersion by additional contacts to achieve the low variation domain of tie line slope.Also,the determination and implementation of the minimum miscibility enrichment are investigated.展开更多
The advent and extensive use of computer and increasing development of different technologies it is important to increase the awareness of issues related to the electronic text or text presentation on computer screen....The advent and extensive use of computer and increasing development of different technologies it is important to increase the awareness of issues related to the electronic text or text presentation on computer screen. The usage of web shows the importance of usability and readability of the web applications or sources provide by the web and web textual contents. Web application fails to encounter the user’s requirements in effective manner specially related to textual information, because the designers are unaware from some of the important factors effecting readability, reading from the screen. In this regard, this study is the continuation of the previous work that has been done for the improvement of readability, to handle the readability issues on the basis of Eye Blink for male participants and female participants. To achieve general recommendations for suitable or optimum length of text line for all type of users on the bases of eye blink. Basically during reading from the computer screen focus losses at two positions, when eye blink in the middle of text line and when text line ends. The study specifies suitable length of text line on the basis of Eye Blink, assuming three typographical variables i.e. font style, font color, font size, and with white background, which improve the overall readability or reading from computer screen. The study also shows two important things the degree of understandability and the degree of attractive appearance of different combination.展开更多
Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straigh...Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straight lines and running conditions of train in high-speed railway station yard. Using the established model, and choosing vehicle lateral acceleration and wheel suspension as the evaluation indexes, dynamic characteristic of vehicle traveling in turnout and adjacent area on main line was analyzed, and effects on travelling safety and stability of train aroused by length variation of straight lines were calculated based on analyzing the damping rules of vibration. The results show that, a certain length of straight lines can alleviate the vibration aroused in turnout and curve(turnout), length of straight lines connecting turnouts in different sections on main line was proposed to meet the demand of traveling stability, and shortening or cancelation of straight line for the scale limitation of station yard has less influence on operation safety of train.展开更多
在混合双馈入直流输电系统中,由于电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)的存在,系统在不同的联络线长度下呈现出不同的高频振荡特征。为研究混合双馈入直流输电系统的...在混合双馈入直流输电系统中,由于电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)的存在,系统在不同的联络线长度下呈现出不同的高频振荡特征。为研究混合双馈入直流输电系统的高频振荡特征及机理,首先建立系统的状态空间模型,基于此研究系统的高频振荡特征,结果表明,由于LCC子系统的存在,在不同的联络线长度下混合双馈入直流输电系统呈现出不同的高频振荡特征。然后,建立混合双馈入直流系统的高频阻抗模型,研究LCC子系统、联络线长度、模块化多电平换流器(modular multilevel converter,MMC)控制链路延时、交流线路长度等对系统高频阻抗的影响。结果表明,对于无电气距离的混合双馈入系统,LCC滤波器的存在使其无高频振荡风险;对于有电气距离的混合双馈入系统,当LCC和MMC子系统之间的电气距离较近时,LCC交流滤波器对系统高频振荡的抑制效果随着联络线长度的增大而减弱。最后,提出混合双馈入系统无高频振荡风险的联络线临界长度确定方法,并通过理论分析和电磁暂态仿真进行有效性验证。展开更多
文摘Gas injection process is a very important technology in enhanced oil recovery.Minimum miscible pressure is one of the key parameters in gas injection processes.Various experimental methods such as slim tube are used to measure MMP.These methods are costly and time consuming.Recently computational methods are used in order to achieve a cost-effective and reliable technique to evaluate MMP.In this work,a new methodology has been proposed for determination of MMP using the minimum tie line length method.A real mixing cell model was developed to estimate the MMP,MME and key tie lines.This method is simple,robust,and faster than conventional one-dimensional simulation of slim tube.The new mixing cells method can accurately determine the whole key tie lines to a shift,regardless of the number of injection gas and reservoir fluid components.Unlike other methods of mixing cells,this method automatically corrects dispersion by additional contacts to achieve the low variation domain of tie line slope.Also,the determination and implementation of the minimum miscibility enrichment are investigated.
文摘The advent and extensive use of computer and increasing development of different technologies it is important to increase the awareness of issues related to the electronic text or text presentation on computer screen. The usage of web shows the importance of usability and readability of the web applications or sources provide by the web and web textual contents. Web application fails to encounter the user’s requirements in effective manner specially related to textual information, because the designers are unaware from some of the important factors effecting readability, reading from the screen. In this regard, this study is the continuation of the previous work that has been done for the improvement of readability, to handle the readability issues on the basis of Eye Blink for male participants and female participants. To achieve general recommendations for suitable or optimum length of text line for all type of users on the bases of eye blink. Basically during reading from the computer screen focus losses at two positions, when eye blink in the middle of text line and when text line ends. The study specifies suitable length of text line on the basis of Eye Blink, assuming three typographical variables i.e. font style, font color, font size, and with white background, which improve the overall readability or reading from computer screen. The study also shows two important things the degree of understandability and the degree of attractive appearance of different combination.
基金Project(2014JBZ012)supported by the Fundamental Research Funds for the Central Universities,China
文摘Taking the development of high-speed railway in China as background, and referring to the dynamic theory and wheel-rail contact mode, dynamic analysis model was established, considering the setting position of straight lines and running conditions of train in high-speed railway station yard. Using the established model, and choosing vehicle lateral acceleration and wheel suspension as the evaluation indexes, dynamic characteristic of vehicle traveling in turnout and adjacent area on main line was analyzed, and effects on travelling safety and stability of train aroused by length variation of straight lines were calculated based on analyzing the damping rules of vibration. The results show that, a certain length of straight lines can alleviate the vibration aroused in turnout and curve(turnout), length of straight lines connecting turnouts in different sections on main line was proposed to meet the demand of traveling stability, and shortening or cancelation of straight line for the scale limitation of station yard has less influence on operation safety of train.
文摘在混合双馈入直流输电系统中,由于电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)的存在,系统在不同的联络线长度下呈现出不同的高频振荡特征。为研究混合双馈入直流输电系统的高频振荡特征及机理,首先建立系统的状态空间模型,基于此研究系统的高频振荡特征,结果表明,由于LCC子系统的存在,在不同的联络线长度下混合双馈入直流输电系统呈现出不同的高频振荡特征。然后,建立混合双馈入直流系统的高频阻抗模型,研究LCC子系统、联络线长度、模块化多电平换流器(modular multilevel converter,MMC)控制链路延时、交流线路长度等对系统高频阻抗的影响。结果表明,对于无电气距离的混合双馈入系统,LCC滤波器的存在使其无高频振荡风险;对于有电气距离的混合双馈入系统,当LCC和MMC子系统之间的电气距离较近时,LCC交流滤波器对系统高频振荡的抑制效果随着联络线长度的增大而减弱。最后,提出混合双馈入系统无高频振荡风险的联络线临界长度确定方法,并通过理论分析和电磁暂态仿真进行有效性验证。
