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Numerical simulation of a buried hot crude oil pipeline during shutdown

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Petroleum Science 2010年第1期7卷 73-82页

作者： Xu Cheng Yu Bo Zhang Zhengwei Zhang Jinjun Wei Jinjia Sun Shuyu Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum Beijing 102249China Zhejiang department Preparatory Team PetroChina West East Gas Pipeline Company Hangzhou Zhejiang 310000 China State Key Laboratory of Multiphase Flow in Power Engineering Xi＇an Jiaotong University Xi＇an Shaanxi 710049 China department of Mathematical Sciences Clemson University Clemson SC 29634-0975 USA

In this paper a mathematical model is built for a buried hot crude oil pipeline during shutdown, and an unstructured grid and polar coordinate grid are respectively applied to generating grids for the soil region and the three layers in the pipe （wax layer, pipe wall, and corrosion-inhibiting coating）. The governing equations are discretized using the finite volume method. The variations in temperatures of static oil and soil were investigated during pipeline shutdown in both summer and winter, in which some important parameters of the soil and crude oils of a Northeast pipeline are employed.

关键词： Moving boundary stagnation point equivalent thermal conductivity thermal influence region unstructured grid

Controlling uncertainty parameters switched systems with time-varying delays in control input

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Controlling uncertainty parameters switched systems with tim...

Characterization of composite particles responsive to electric and magnetic fields

第八届中国不确定系统年会

作者： Gao Fengyin,Guo Yanli department of applied Mathematics and physics, School of Air Force Engineering university,xi''an 710051,{4.

＜正＞This article gives a novel criterion for the asymptotic stabilization of the zero solutions of a class of switched systems with delays in control input. By constructing Lyapunov functional,we obtained the criterion which is expressed in terms of matrix *** results are more advanced than the *** examples are presented to illustrate the effectiveness of the theoretical results.

关键词： asymptotic stability Lyapunov function linear matrix inequality time delay

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Progress in Natural Science:Materials International 2004年第10期 72-76页

作者： ZHAO xiaopeng and GUO Hongxia (Institute of Electrorheological Technology,department of applied physics,Northwestern Polytechnical university,xi’an710072,{4.)

The multilayer particles with responses to electric and magnetic fields are a prerequisite for particles assembled under ex-ternal *** routes to produce particles responsive to electric and magnetic fields are presented in this *** size and morphol-ogy,properties as well as the electric-magnetic responses of three kinds of particles are comparatively *** will provide a useful basis for the control of the behavior of the particles in suspensions by external electric and magnetic fields.

关键词： composite particles morphology electric-magnetic response

A New Method of Studying Surface Activity for Liquid Alloys

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Semiconductor Photonics and Technology 1997年第2期3卷 69-73,77页

作者： YANG Yongzheng (department of applied physics,Northwestern Polytechnical university,xi’an 710072,CHN) YANG Jun (xi’an Dali Instrument Research Institute,xi’an 710054.CHN)

In order to research surface characteristics of liquid metal which based on hydrodynamics theory and interaction principle between laser wave and surface tension stationary wave of liquid metal,it is finished to provide an entirely theoretical equation,apparatus and techniques of the measuring the surface tension for liquid metal at high *** apparatus is an automatic measuring system for information collecting and processing,in which a computer is attached to charge coupled device,driving circuits and A/D converter. Applying the new apparatus the surface tension values of Sn-Pb based binary and ternary alloy solders have been obtained on the basis of the above *** experimental results indicate that the surface tension values of liquid metal Sn-Pb based solders are decreased by 37.3% and 31.9% *** 1% of Bi or In is added in the solders,the elements Bi and In have evident surface activity in Sn-Pb based solders and the wettability of the solders is increased with increasing surface activity.

关键词： Liquid Metal Solder Surface Activity Element Surface Tension Wettability

Delay-Independent Robust Stability and Stabilization for Uncertainty Parameters Discrete-time Switched System with Time Delays

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Delay-Independent Robust Stability and Stabilization for Unc...

第八届中国不确定系统年会

作者： Gao Fengyin,Dou Haili department of applied Mathematics and physics,School of Air Force Enginieering university xi''an 710051,{4.

＜正＞In this paper,we obtain some criteria for determining the asymptotic stability of the zero solution for some classes of discrete time switched systems, and delay-independent robust stability and stabilization of *** mainly used a discrete version of the second Lyapunov method and linear matrix inequality *** examples proved that it works.

关键词： asymptotic stability Lyapunov function linear matrix inequality time delay

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一阶广义分布参数系统的指数稳定性

系统科学与数学 2010年第3期30卷 315-322页

作者：袁燕飞葛照强西安交通大学应用数学系西安710049

利用退化半群的方法讨论了Hilbert空间中一阶广义分布参数系统的指数稳定性,并给出了判断指数稳定性的充要条件.

关键词：退化Co-半群一阶广义分布参数系统指数稳定性

Dependence of the coefficient of ultrasonic velocity on the coefficient of free length in organic liquids

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Chinese Journal of Acoustics 2000年第1期19卷 79-82页

作者： LU Yigang PENG Jianxin (department of applied physics, South china {4. of Technology Guangzhou 51064.) TONG Jie DONG Yanwu (applied Acoustics institute, Shaanxi Normal {4. xi’an 710062) department of applied physics South China University of Technology Guangzhou510641 applied Acoustics Institute Shaanxi Normal University Xi'an710062

On the basis of Jacobson's free length theory and the theory of pressure coefficient and temperature coefficient of free length in liquids, the relationship between the pressure coefficient of ultrasonic velocity and the pressure coefficient of free length, and the relationship between the temperature coefficient of ultrasonic velocity and the temperature coefficient of free length were studied. Relevant equations were given, and the pressure coefficient and temperature coefficient of ultrasonic velocity were calculated, which are in agreement with the measured values.

关键词： length Dependence of the coefficient of ultrasonic velocity on the coefficient of free length in organic liquids free

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CVT光伏泵水系统瞬态工作点特性分析

太阳能学报 2002年第5期23卷 554-556页

作者：苑进社余世杰何慧若西安理工大学应用物理系西安710048 合肥工业大学能源研究所合肥230009

采用定电压跟踪器 (CVT)的光伏水泵系统在不同地区已成功地投入实际应用。实地运行数据表明 ,CVT不能适应太阳电池阵列伏安特性的变化 ,使系统瞬态工作点偏离阵列输出最大功率点 ,导致系统功率损失。该文报道 2 .5kWp光伏水泵系统的基... 详细信息

采用定电压跟踪器 (CVT)的光伏水泵系统在不同地区已成功地投入实际应用。实地运行数据表明 ,CVT不能适应太阳电池阵列伏安特性的变化 ,使系统瞬态工作点偏离阵列输出最大功率点 ,导致系统功率损失。该文报道 2 .5kWp光伏水泵系统的基本构成和典型实地运行数据。

关键词： CVT 光伏水泵系统瞬态工作点定电压跟踪器光机电一体化

Corona Regime of Dual Bar Against a Plane

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Corona Regime of Dual Bar Against a Plane