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Gas equilibrium heat capacity synthesis under the influence of acoustic relaxation process and its application in gas detection

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Chinese Journal of Acoustics 2019年第4期38卷 386-402页

作者： zhang Kesheng zhang xiangqun SHAO Fang School of Electrical and Information Engineering Guizhou Institute of TechnologyGuiyang 550003 School of Electronic Information and Communications Huazhong University of Science and TechnologyWuhan 430074 School of Mechanical Engineering Guizhou Institute of TechnologyGuiyang 550003

In an excitable gas,the molecular vibration relaxation process caused by an acoustic disturbance leads the equilibrium heat capacity to the effective one that depends on the acoustic frequency,resulting in acoustic dispersion and acoustic relaxational *** on the algorithm of synthesizing a single-relaxation process,we develop a synthesizing method to get the equilibrium heat capacities of excitable gases from the two-frequency acoustic speed and absorption *** two measurement frequencies are selected in the range where the acoustic relaxational absorption is *** method can obtain the heat capacities of internal and external degrees of freedom of gas molecules respectively,and effectively eliminate the influence of the acoustic relaxation process on the measurement results of excitable gas heat *** various gases,consisting of CO2,CH4,Cl2,N2 and O2 at room temperature,the gas heat capacities obtained in this paper agree with the thermodynamic theoretical calculations based on the Planck-Einstein formula,and the maximum relative error is 3.51% in comparison to the experimental *** synthesized heat capacities of rotation and vibration can be applied to the detection of gas molecular geometry,vibration frequency and mole fractions of gas mixtures.

关键词： relaxation equilibrium gases

Lattice Boltzmann Method used for the aircraft characteristics computation at high angle of attack

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Science China(Technological Sciences) 2010年第8期53卷 2068-2073页

作者： DU TeZhuan,LI xiangqun,zhang XiaLing&WANG YiWei College of Engineering,Peking University,Beijing 100871,China 1. College of Engineering Peking University Beijing 100871 China

Traditional Finite Volume Method(FVM)and Lattice Boltzmann Method(LBM)are both used to compute the high angle attack aerodynamic characteristics of the benchmark aircraft model named *** though the software requires flow on the order of Ma<0.4,simulation at Ma=0.5 is run in PowerFLOW after theoretical *** consistency with the wind tunnel testing is satisfied,especially for the LBM which can produce perfect results at high angle *** can accurately capture the detail of flows because it is inherently time-dependent and parallel and suits large-scale computation very well.

关键词： LBM CFD high AOA

Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

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Chinese Journal of Acoustics 2018年第2期37卷 202-218页

作者： zhang Kesheng zhang xiangqun TANG Wenyong XIAO Yingqun JIANG Xueqin School of Electrical and Information Engineering~ Guizhou Institute of Technology Guiyang 550003 School of Electronic Information and Communications Huazhong University of Science and Technology Wuhan 430074 School of Big Data Guizhou Institute of Technology Guiyang 550003

To research the correlation between vibrational energy transition rates and acoustic relaxation processes in excitable gases, the vibrational relaxation theory provided by Tanczos [J. Chem. Phy3. 25, 439 （1956）] is applied to calculate the energy transition rates of Vibrational- Vibrational （V-V） and Vibrational-Translational （V-T） energy transfer in gas mixtures. The results of calculation for the multi-relaxation processes in various gas mixtures, consisting of carbon dioxide, methane, chlorine, nitrogen, and oxygen at room temperature, demonstrate that the acoustic energy stagnated in every vibrational mode is coupled with each other through V-V energy exchanges. The vibrational excitation energy will relax through the V-T de-excitation path of the lowest mode because of its fastest V-T transition rate, resulting in that only one absorption peak can be measured for most of excitable gas mixtures. Thus, an effective model is provided to analyze how the vibrational energy transition rates affect the characteristics of acoustic relaxation processes and acoustic propagation in excitable gas mixtures.

关键词： Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

Risk assessment study on bridge foundation in deep overlying stratum

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Engineering Sciences 2012年第3期10卷 38-43页

作者： zhang xiangqun Wang Jingguo Liu Manhong Jiangsu Provincial Yangtze River Highway Bridge Construction Commanding Department Taizhou Jiangsu 225321 China College of Geological Sciences and Engineering Hohai University Nanjing 210098 China

Based on the analysis about the hydrogeological conditions and engineering geological conditions, this paper makes analysis on the possible risks of the deep overlying stratum foundation and establishes the risk evaluation index system during the foundation operating period. Such methods as analytic hierarchy process （AHP） , Delphi method and fuzzy comprehensive evaluation method are adopted to make the quantitative analysis on the risk factors and establish the risk judgment model. According to the actual engineering of Taizhou Bridge, the paper evaluates the risk of the foundation during the operating period at the condition of deep overlying stratum. The evaluation results can provide the reference for the risk management of the bridge foundation durin~ the ooerating period.

关键词： risk assessment deep overlying stratum suspension bridge AHP

Improvement of refrigerant capacity of La_(0.67)Ca_(0.33)MnO_(3) single crystal with a few percent Fe doping

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Science China(Physics,Mechanics & Astronomy) 2009年第6期52卷 809-812页

作者： LI GuoKe, zhang xiangqun, KOU ZhiQi, LI QingAn, SUN Young & CHENG ZhaoHua State Key Laboratory of Magnetism, Beijing National Laboratory of Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China State Key Laboratory of Magnetism Beijing National Laboratory of Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China

Large low-field-induced magnetic entropy changes, ΔSM, are observed in La0.67Ca0.33MnO3 and La0.67-Ca0.33Mn0.96Fe0.04O3 single crystals. The peaks of ΔSM broadened asymmetrically to high temperatures under higher magnetic fields for two materials should be attributed to the first-order magnetic phase transition at Tc. A small amount of iron doping results in an increase in the refrigerant capacity of the material though the magnetic entropy change decreases. The discovery of excellent magnetocaloric features of these single crystals in the low magnetic field can provide some ideas for exploring novel magnetic refrigerants operating under permanent magnet rather than superconducting one as magnetic field source.

关键词： single crystal magnetic entropy refrigerant capacity

声弛豫过程影响下的气体平衡态热容合成方法及其在气体检测中的应用

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声学学报 2020年第3期45卷 394-403页

作者：张克声张向群邵芳贵州理工学院电气与信息工程学院贵阳550003 华中科技大学电子信息与通信学院武汉430074 贵州理工学院机械工程学院贵阳550003

声扰动形成的分子振动弛豫过程使得气体热容成为依赖于声频率的有效热容,导致随频率变化的声速频散和声弛豫吸收。本文基于单弛豫过程合成算法,提出一种基于两频点声速和声吸收测量值的气体平衡态热容合成方法。该方法两个测量声频点只... 详细信息

声扰动形成的分子振动弛豫过程使得气体热容成为依赖于声频率的有效热容,导致随频率变化的声速频散和声弛豫吸收。本文基于单弛豫过程合成算法,提出一种基于两频点声速和声吸收测量值的气体平衡态热容合成方法。该方法两个测量声频点只需在声弛豫吸收显著的频率范围即可分别合成可激发气体分子内外自由度热容,并有效消除声弛豫过程对气体平衡态热容测量结果的影响。对于室温下由CO2、CH4、Cl2、N2和O2组成的多种气体,合成的气体热容值与基于Planck-Einstein公式的热力学理论计算结果相符,相比实验数据最大相对误差为3.51%。合成的转动和振动热容还可应用于气体分子几何结构、振动频率大小和混合气体摩尔分数的检测。

关键词：弛豫过程吸收系数气体分子背景气体摩尔分数平衡态混合气体合成方法气体检测

基于声速频散谱弛豫特征的油中溶解气体检测方法

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电力系统保护与控制 2023年第3期51卷 173-180页

作者：张向群王晓静刘婷婷杜根远张帆许昌学院信息工程学院河南许昌461000 河南轻工职业学院机电工程系河南郑州450008 湖北第二师范学院物理与电子信息学院湖北武汉430205

针对传统气体检测方法难以满足电力运营部门大范围低成本实时监控油浸式电力设备问题,提出一种利用3个频率点声速测量值获取声速频散谱弛豫特征进行气体监测方法。首先,通过推导有效压缩系数与声弛豫过程理论公式,简化声速频散谱表达式... 详细信息

针对传统气体检测方法难以满足电力运营部门大范围低成本实时监控油浸式电力设备问题,提出一种利用3个频率点声速测量值获取声速频散谱弛豫特征进行气体监测方法。首先,通过推导有效压缩系数与声弛豫过程理论公式,简化声速频散谱表达式。其次,根据不同频率点声速测量值重建声速频散谱,抽取油浸式电力设备故障气体声速频散谱弛豫声速和弛豫频率。最终,利用弛豫特征定性定量检测气体成分。仿真结果显示重建声速频散谱与实验数据相符,完成了CH_(4)、CO_(2)等多种气体检测,为实时在线监测电力设备油中溶解气体成分提供一种低成本、测量简单的声学方法。

关键词：油中溶解气体分析声弛豫电力设备气体监测声速频散谱

维普期刊数据库博看期刊

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基于三频点声速测量的气体压强合成算法

计算物理 2022年第4期39卷 411-417页

作者：张向群杜根远刘婷婷许昌学院信息工程学院河南许昌461000 湖北第二师范学院物理与电子信息学院湖北武汉430205

利用声速测量精度高,测量方法简单的特点,提出一种基于三个频率点测量声速合成气体压强的算法。首先在三个频率点测量声速,然后计算得到声速频散谱拐点的弛豫频率,最后根据弛豫频率与压强成线性正比的关系得到气体压强,仿真结果验证了... 详细信息

利用声速测量精度高,测量方法简单的特点,提出一种基于三个频率点测量声速合成气体压强的算法。首先在三个频率点测量声速,然后计算得到声速频散谱拐点的弛豫频率,最后根据弛豫频率与压强成线性正比的关系得到气体压强,仿真结果验证了该算法的可行性。为在线实时检测气体腔体压强提供了一种技术简单、精度高的超声方法。

关键词：声学测量声弛豫频率气体压强超声检测

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胡云英运用桂枝抑肝的经验

浙江中医杂志 2007年第3期42卷 142-143页

作者：章向群浙江省开化县中医院浙江开化324300

传云“木得桂而枯”,森林中有肉桂是否会导致其他树木难以长养,实在未能考证。但是在中医临床中桂枝的抑肝作用则是非常明显的。胡云英主任医师业医四十余载,临床经验丰富。笔者侍诊多年,兹将其运用桂枝抑肝治疗疑难病的经验给予总结,... 详细信息

传云“木得桂而枯”,森林中有肉桂是否会导致其他树木难以长养,实在未能考证。但是在中医临床中桂枝的抑肝作用则是非常明显的。胡云英主任医师业医四十余载,临床经验丰富。笔者侍诊多年,兹将其运用桂枝抑肝治疗疑难病的经验给予总结,以飨同道。[第一段]

关键词：桂枝抑肝胡云英医案