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61.
In this paper we study the occurrence of chaos for charged particles moving around a Schwarzschild black hole, perturbed by uniform electric and magnetic fields. The appearance of chaos is analyzed resorting to the Poincaré-Melnikov method.  相似文献   
62.
关奉伟  刘巨 《中国光学》2013,(6):919-929
根据空间应用电子设备的热控要求,对空间光学遥感器的控制电箱进行了热控设计。首先,总结了空间电子设备的热设计原则。针对空间光学遥感器控制电箱介绍了相应的热设计流程,对典型的大功率器件进行了温差推算,并说明了电箱的各电路板和大功率元器件的热设计方案。最后,通过热分析和热试验手段对热控电箱的热控方案进行了验证。试验结果表明:控制电箱的整机稳态工况热平衡温度小于30℃,各元器件的最高壳温在54.2℃以内。结果验证了该设计方案完全满足设计指标要求。  相似文献   
63.
The Laser Undulator Compact X-ray source(LUCX) is a test bench for a compact high brightness X-ray generator,based on inverse Compton Scattering at KEK,which requires high intensity multi-bunch trains with low transverse emittance.A photocathode RF gun with emittance compensation solenoid is used as an electron source.Much endeavor has been made to increase the beam intensity in the multi-bunch trains.The cavity of the RF gun is tuned into an unbalanced field in order to reduce space charge effects,so that the field gradient on the cathode surface is relatively higher when the forward RF power into gun cavity is not high enough.A laser profile shaper is employed to convert the driving laser profile from Gaussian into uniform.In this research we seek to find the optimized operational conditions for the decrease of the transverse emittance.With the uniform driving laser and the unbalanced RF gun,the RMS transverse emittance of a 1 nC bunch has been improved effectively from 5.46 πmm.mrad to 3.66 πmm.mrad.  相似文献   
64.
The dynamic characteristics of measured uncertainty and quantum coherence are explored for an inertial Unruh–DeWitt detector model in an expanding de Sitter space. Using the entropic uncertainty relation, the uncertainty of interest is correlated with the evolving time t, the energy level spacing δ, and the Hubble parameter H. The investigation shows that, for short time, a strong energy level spacing and small Hubble parameter can result in a relatively small uncertainty. The evolution of quantum coherence versus the evolving time and Hubble parameter, which varies almost inversely to that of the uncertainty, is then discussed, and the relationship between uncertainty and the coherence is explicitly derived. With respect to the l1 norm of coherence, it is found that the environment for the quantum system considered possesses a strong non-Markovian property. The dynamic behavior of coherence non-monotonously decreases with the growth of evolving time. The dynamic features of uncertainty and coherence in the expanding space with those in flat space are also compared. Furthermore, quantum weak measurement is utilized to effectively reduce the magnitude of uncertainty, which offers realistic and important support for quantum precision measurements during the undertaking of quantum tasks.  相似文献   
65.
In this paper, we study the Noether-form invariance of nonholonomic mechanical controllable systems in phase space. Equations of motion of the controllable mechanical systems in phase space are presented. The definition and the criterion for this system are presented. A new conserved quantity and the Noether conserved quantity deduced from the Noether-form invariance are obtained. An example is given to illustrate the application of the results.  相似文献   
66.
夏小建 《大学物理》2011,30(8):22-24,29
对经典一维受迫谐振子量子化,求解量子化后体系的时间演化算符.应用相空间准概率分布函数,研究了体系的量子特性.研究结果表明,初始为真空态,经过时间演化,系统波函数是一个二维高斯波包;波包中心的振幅和相位受到作用力的调制,成为调幅、调相波,波包中心的运动与经典受迫谐振子的运动形式相同.  相似文献   
67.
In this work, a new model of the magneto-thermoelasticity theory has been constructed in the context of a new consideration of heat conduction with fractional derivative. A one-dimensional application for a conducting half-space of thermoelectric elastic material, which is thermally shocked in the presence of a magnetic field, has been solved using Laplace transform and state-space techniques (Ezzat, 2008 [1]). According to the numerical results and its graphs, a conclusion about the new theory of magneto-thermoelasticity has been constructed. The theories of coupled magneto-thermoelasticity and of generalized magneto-thermoelasticity with one relaxation time follow as limited cases. The result provides a motivation to investigate conducting thermoelectric materials as a new class of applicable materials.  相似文献   
68.
We first review the Coset Space Dimensional Reduction (CSDR) programme and present the best model constructed so far based on the , 10‐dimensional E8 gauge theory reduced over the nearly‐Kähler manifold with the additional use of the Wilson flux mechanism. Then we present the corresponding programme in the case that the extra dimensions are considered to be fuzzy coset spaces and the best model that has been constructed in this framework too. In both cases the best model appears to be the trinification GUT .  相似文献   
69.
根据透镜组基点性质和透镜组可变焦原理 ,设计定第二主点变焦光学系统。该系统用于视力矫正 ,在变焦过程中 ,“眼镜片光心”相对于眼睛的位置保持不变 ,是一种新型的光学变焦系统。用它可对近视、远视、散光等非正视眼进行快捷、准确的验光。  相似文献   
70.
相空间中的Noether定理及其应用   总被引:1,自引:0,他引:1  
从修改的哈密顿变分原理出发导出相空间的 Noether 定理,对正则拉氏量系统,分析该系统在相空间中的对称性质,可导出其相应的守恒量,而这种相空间中的对称性质在位形空间中常常又是不呈现出来的.对奇异拉氏量系统,该系统具有 Dirac约束,我们分析了约束系统的对称性质,讨论了 Dirac 猜想是否有效.  相似文献   
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