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991.
Atomic coherent states as energy eigenstates of a Hamiltonian describing a two-dimensional anisotropic harmonic potential in a uniform magnetic field 下载免费PDF全文
In this paper we find that a set of energy eigenstates of a two-dimensional anisotropic harmonic potential in a uniform magnetic field is classified as the atomic coherent states |τ> in terms of the spin values of j in the Schwinger bosonic realization. The correctness of the above conclusions can be verified by virtue of the entangled state <η| representation of the state |τ>. 相似文献
992.
The symmetry and |m| partial-wave analysis for two-dimensional (2D) Coulomb-scattering is investigated. As a function of energyE, the |m| partial-wave scattering amplitudef
|m|(θ) is analytically continuated to the, negativeE (complexk) plane, and it is found that the bound state energy eigenvalues (E<0) are just located at the poles off
|m|(θ) on the positive imaginaryk axis as is expected. In addition, as a function of |m|,f
|m|(θ) is analytically continuated to the complex |m| plane, the bound state energy eigenvalues are just located at the poles
off
|m|(θ) on the positive real |m| axis. 相似文献
993.
994.
The gas temperature within hypersonic boundary layer flow is so high that the specific heat of gas is no longer a constant but relates to temperature. How variable specific heat influences on boundary layer flow stability is worth researching. The effect of the variable specific heat on the stability of hypersonic boundary layer flows is studied and compared with the case of constant specific heat based on the linear stability theory. It is found that the variable specific heat indeed has some effects on the neutral curves of both the first-mode and the second-mode waves and on the maximum rate of growth also. Therefore, the relationship between specific heat and temperature should be considered in the study of the stability of the boundary layer. 相似文献
995.
Equilibrium statistics of a cluster of a large number of positive two-dimensional point vortices in an infinite region and the associated thermodynamic functions, exhibiting negative temperatures, are evaluated analytically and numerically from a microcanonical ensemble. Extensive numerical simulations of vortex motion are performed to verify the predicted equilibrium configurations. An application of Kubo's linear response theory is used to study the nonequilibrium situation that results from placing a cluster, of vortices in a weak external velocity field, such as that produced by a distant vortex cluster. The weak field causes the cluster to grow in size as if there were an effective positive eddy viscosity. When a number of clusters interact, the effect is for each to grow while the distances between them decrease with time. The latter effect is an exhibit of negative viscosity. The application of this to the motion of the atmosphere is discussed.Supported in part by National Science Foundation Grant GK-40263.Advanced Study Program, National Center for Atmospheric Research (sponsored by the National Science Foundation). 相似文献
996.
997.
Two series of new liquid crystailine polymers with T-shaped two-dimensional mesogenicunits were synthesized by low temperature solution polycondensations of 4-substituted N-2, 5- dihydroxybenzylidene aniline monomers with different diacyl dichlorides. The polymerswere found to be nematic and shown liquid crystailine behavior. The melting temperatureT_m and the clearing temperature T_i of the polymers change regularly with varying of themonomer structures. 相似文献
998.
本文介绍了一种测量二维形状飞片的光探测系统及其数据处理方法。为了便于说明,用一个一点起爆爆轰事件作为实际示例。其数据处理结果与闪光x光测量结果作了比较,发现在飞片形状和压力两方面都能很好地符合。 相似文献
999.
采用高分辨采样二维液相色谱法(HiRes 2D-LC)对金银花中绿原酸和木犀草苷进行准确定量分析。第一维液相色谱采用C18色谱柱,以乙腈和0.4%(v/v)磷酸水溶液为流动相进行梯度洗脱;第二维液相色谱采用SB-Phenyl色谱柱,以乙腈和0.5%(v/v)乙酸水溶液为流动相进行梯度洗脱;二维接口采用五位十通阀,并配置2个多中心切割阀,对绿原酸组分和木犀草苷组分进行多次连续切割。实验结果表明,二维液相色谱分析提高了绿原酸和木犀草苷色谱峰的确认能力,可揭示一维液相色谱分析中共洗脱或隐藏峰的信息;高分辨采样模式实现了一维目标组分的片段式整峰切割,提高了二维液相色谱分析的准确定量能力;通过线性关系、基质加标回收和重复性等考察结果,表明高分辨采样二维液相色谱具有优异的定量准确性和重复性,为中药等复杂基质组分样品的分离和准确定量提供了新方法。 相似文献
1000.
研究了二维离子色谱测定海水中铵离子的方法。海水样品经10倍稀释,一维色谱采用高容量的CS–165 mm柱,以30 mmol/L甲磺酸溶液等度淋洗,流量为1 m L/min,进样25μL,CSRS–300 4 mm抑制电导分离Na+,NH4+;二维色谱采用CS–12A 4 mm柱,以8 mmol/L甲磺酸溶液等度淋洗,流量为1 m L/min,以1 300μL定量环进样,SC–CSRS–300盐转换器抑制电导检测NH4+。结果表明:色谱峰面积与NH4+质量浓度线性相关,相关系数为0.999 9。10μg/L标准溶液测定结果的相对标准偏差为2.7%(n=7),NH4+的方法检出限和仪器检出限分别为0.42,0.05μg/L,海水中NH4+加标回收率为80.8%~105.8%。 相似文献