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971.
提出了一种研究折板及多面板类结构非线性弯曲行为的样条核质点法.方法包括以下步骤:(1)将折板及多面板结构模拟成不同平面上平板的集合体;(2)基于冯.卡门的大挠度理论,使用一阶剪切变形理论和样条核质点法先分析各平板的几何非线性行为;(3)将经过修正的各板的非线性刚度矩阵叠加得到整个折板结构的非线性刚度矩阵;(4)研究整个结构的几何非线性行为.由于摆脱了网格的束缚,本文方法可以避免网格扭曲引起的网格重构问题.文末通过几个算例将本文方法解与使用壳单元的ANSYS有限元解或已有文献解进行对比,验证了本文方法的收敛性和准确性. 相似文献
972.
测度值分枝过程与移民过程 总被引:8,自引:0,他引:8
本文介绍了测度值分枝过程和由斜卷积半群定义的伴随移民过程的基本理论和研究现状,主要内容包括:分枝粒子系统的收敛;超过程的基本正则性和极限定理;非线性微分方程;广义分枝模型;斜卷积半群和进入律;用Kuznetsov过程构造移民过程等。 相似文献
973.
974.
In the present paper, the algorithm of Binary Image Cross-Correlation (BICC) was developed to measure the unsteady flow field.
A vortex flow field was used to test the algorithm by numerical simulation. The results show that BICC is an effective algorithm
for particle identification from consecutive images, the accurate velocity vector field can be obtained. The real velocity
field in a valve chamber was measured by BICC in this study. From the full-field velocity information, the pressure and vorticity
fields were also extracted by post-processing.
The project supported by the National Natural Science Foundation of China 相似文献
975.
热解涂层石墨管性能测试及其若干问题探讨 总被引:1,自引:0,他引:1
用石墨炉原子吸收光谱仪对国产热解涂层石墨管的使用寿命,灵敏度,精度等性能指标进行测试,并针对正常状态,原子化温度过高,载气不纯等几种不同条例下测试对石墨性能的影响进行了讨论,得出了对实际应用有参考价值的结论。测试时提界定较严格,选定典型的难熔金属元素V作为被测元素,有较强的代表性。 相似文献
976.
Lee Jinn-Shing Hsu Chung-King Lin Li-Kuo Huang Chin-Wang 《Journal of Thermal Analysis and Calorimetry》1999,56(1):223-226
Thermal decomposition of Zr/KClO4 priming compositions containing different concentration of additives, such as graphite, Fe2O3 and Al2O3 have been studied by DSC/TG techniques. The firing characteristics of these primer mixtures have also been examined by Bruceton
test and by adiabatic calorimeter. The results of these experiments suggest that strong interaction has been occurred between
KClO4 and Fe2O3 in the solid state.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
977.
Tan Zhi-Cheng Zhang Ji-Biao Shang-He Meng 《Journal of Thermal Analysis and Calorimetry》1999,55(1):283-289
A computerized adiabatic calorimeter for heat capacity measurements in the temperature range 80–400 K has been constructed.
The sample cell of the calorimeter, which is about 50 cm3 in internal volume, is equipped with a platinum resistance thermometer and surrounded by an adiabatic shield and a guard
shield. Two sets of 6-junction chromel-copel thermocouples are mounted between the cell and the shields to indicate the temperature
differences between them. The adiabatic conditions of the cell are automatically controlled by two sets of temperature controller.
The reliability of the calorimeter was verified through heat capacity measurements on the standard reference material α-Al2O3. The results agreed well with those of the National Bureau of Standards (NBS): within ±0.2% throughout the whole temperature
region. The heat capacities of high-purity graphite and polystyrene were precisely measured in the interval 260–370 K by using
the above-mentioned calorimeter. The results were tabulated and plotted and the thermal behavior of the two materials was
discussed in detail. Polynomial expressions for calculation of the heat capacities of the two substances are presented.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
978.
S. Cebulak A. Gawęda A. Langier-Kużniarowa 《Journal of Thermal Analysis and Calorimetry》1999,56(2):917-924
This paper presents the results of oxyreactive thermal analyses of organic matter in rocks, heated naturally during diagenetic
to metamorphic processes. During the experiments we traced the reactions in the temperature range up to 900°C, it means from
the very beginning of diagenetic transformations to the highest real temperatures acting in the Earth's crust as a solid phase.
The results showed that TA could be a tool for the reconstruction of thermal regime in natural coal-bearing systems.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
979.
Particle Deposition in Porous Media: Analysis of Hydrodynamic and Weak Inertial Effects 总被引:1,自引:0,他引:1
We have studied the transport and capture of non-Brownian particles in porous media, when the particles are mainly submitted to hydrodynamic and weak inertial effects. Visualization experiments have been performed using several models of porous media which consist of transparent etched networks of interconnected channels. Typical particle deposits have been observed at the corners of the grains of the porous medium. Their shape and their orientation were dependent on flow rate and on the anisotropy of the flow field. A trajectory analysis model has been applied to a porous medium made of a doubly periodic array of rectangular grains very close to the experimental model. This numerical model has been used to localize particle deposits and to determine particle capture efficiency on the grains over a range of low Stokes numbers, grain aspect ratios and flow-field anisotropy ratios. The results have been interpreted in terms of shape of particle deposits and compared successfully to experimental observations. 相似文献
980.
IntroductionTurbulentflowladenwithparticlesisacommonocurenceinbothnatureandindustry.Recentresearchhasshownthattheparticlecon... 相似文献