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高庆弟 《核聚变与等离子体物理》1987,(4)
利用张量等离子体的平衡方程,研究了托卡马克等离子体中由各向异性引起的等压强面相对于碰面的偏离及其变化规律,并对张量等离子体的自由边界平衡问题进行了计算。等压强面相对于碰面的偏离与压强的剖面分布有密切关系,且在各向异性较强的等离子体中,平行和垂直压强分量等值面的偏离行为是完全不同的。 相似文献
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本文在电力平方反比定律偏离平方反比的情况下推导了点电荷电场中通过球面 S 的电通量的表达式,与高斯定理相比,讨论了偏离平方反比带来的影响,并在宏观、微观(原子核线度)范围内计算了偏离系数。在任意曲面 S 的情况对偏离系数进行了估算.计算结果表明,在近代实验所确定的指数偏差下,偏离平方反比对高斯定理的影响很小。 相似文献
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随着真空技术的发展(极高真空、真空校准、吸附型真空泵、复杂结构的真空设备等等),提出了一系列偏离麦克斯韦分布的理论问题.那么,真空技术中的非麦氏分布问题究竟有哪些?可不可以求解?解答的原则如何?引起许多人的关注.现在提出拙见,抛砖引玉.我们已知,气体分子运动论是以麦克斯韦分布津为基础对大量分子进行统计.所以,稀薄气体或超稀薄气体的非麦氏分布问题可以概括为两类:(1)麦氏分布律本身的偏离:温度、.... 相似文献
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本文详细讨论了试件在空间六个自由度中产生刚体运动时所形成的云纹图特性,定量地分析了各种刚体运动形式对云纹干涉法的影响。经分析表明:在用云纹干涉法测量变形位移场时,只有当试件绕坐标轴刚体转动时才会影响所测变形位移场。 相似文献
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虚功原理又称虚位移原理,它是借助功能关系求解静力学问题的一种方法.其应用的基本步骤为:先假设系统内各质点发生无限小位移,再分析哪些力做功并计算功的数值,最后根据系统的功能关系列出方程并求解.下面通过几例竞赛题说明具体的使用方法. 相似文献
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Body stress flow can be expected in the fast ignition imploding of the inertial fusion process that strongly damps small‐scale velocity structures. The Weibel instability is one of the plasma instabilities that require anisotropy in the distribution function. The body stress effect was neglected in the calculation of the Weibel instability growth rate. In this article, the propagation condition of impinging waves and the growing modes of the Weibel instability on the plasma density gradient of the fuel fusion with the body stress flow are investigated. Calculations show that the minimum value of the body stress rate threshold in the linear polarization is about 2.96 times greater than that of the circular polarization. Increasing 10 times of the density gradient and decreasing 2 times of the wavelength in the linear polarization and the circular polarization, respectively, lead to about 1.78 × 106 times increment and 0.019 times decrement in the maximum of the Weibel instability growth rate. Also, the Weibel instability growth rate maximum in the circular polarization is about 107 times greater than that of the linear polarization. The body stress flow and the density gradient tend to stabilize the Weibel instability in the circular polarization and act as a destabilizing source in the linear polarization. Therefore, by increasing steps of the density gradient plasma near the relativistic electron beam‐emitting region, in the circular polarization, the Weibel instability occurs at a higher stress flow. 相似文献
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Scaling left ventricular (LV) mass and other cardiac dimensions to account for individual body size is important. The traditional method of simple ratio scaling using, for example, body surface area (BSA) assumes a linear and proportional relationship and accurate measurement of both LV mass and BSA. These assumptions can be questioned; hence, we examined the appropriateness of methods and different indices using highly accurate magnetic resonance imaging scans. Cardiac and whole-body scans were performed in 172 young, healthy, male subjects (age range, 17-28 years) to assess LV mass, volume, linear dimensions, lean body mass and fat mass. Height, body mass and BSA were determined anthropometrically. Relationships were examined for linearity and closeness of fit using log-log least-squares linear regression to determine the slope exponent b (where 1.0 indicates linearity). The relationship between LV mass and lean body mass (b=.90+/-.15; r(2)=.66) was linear and geometrically consistent. This was also the case for LV end-diastolic volume (b=.70), although the confidence intervals were broader (+/-0.32) and the r(2) (.31) smaller. The relationships between LV mass, volume and other variables were generally not linear or geometrically consistent. LV linear dimensions did not demonstrate any linear relationships, and in particular, those with BSA were extremely poor (r(2)=.02-.09). In summary, the traditional scaling of LV measurements to BSA does not remove the influence of body size and other techniques should be considered. Lean body mass was the most appropriate variable for simple indexing of LV mass. No body size variable had a linear and proportional relationship with LV linear dimensions, and the use of simple ratio scaling for these is seriously questioned. 相似文献
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