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1.
我们在教学过程中发现,课本中一些演示实验和一些学生实验采用的器材可操作性不强,往往会影响实验的结果.如果把一些实验的器材在原来的基础上加以合理改进,减小原来实验器材不足存在的影响,可以使得一些实验的对比性增强,还会大大地提高一些实验的成功率.  相似文献   

2.
磁场对水作用机制的计算机模拟研究   总被引:9,自引:0,他引:9  
卢贵武 《物理》1997,26(11):679-682
介绍了对水系统进行计算机模拟研究的方法和常用的一些位势模型,报道了磁处理水研究进展和计算机模拟研究的一些结果。  相似文献   

3.
多体体系输运理论——反常扩散   总被引:2,自引:0,他引:2  
主要介绍最近在多体体系输运理论的一些模型和动力学等工作, 特别是一些有关反常扩散方面的工作结果.  相似文献   

4.
利用数字信号处理技术,可直接应用微机而不用锁定放大器来检测物质的光声信号。本文给出用互功谱技术和多次平均方法所得的一些实验结果。当炭黑和黄色金刚石粉末为试样时,用微机和用锁定放大器所得到的光声信号的相位和幅值都非常吻合。文章还给出了用这数字信号处理技术检测一些薄型不透光试样的热扩散率的实验结果。这些结果与用激光导热仪所测得的结果也良好地相符合。  相似文献   

5.
本文提出了用定向散斑屏作为编码器的白光图像处理新技术。和其它一些编码方法相比较,它有一些明显的优点。作为实验演示,本文给出了彩色图像档案存贮和等密度假彩色编码的实验结果。  相似文献   

6.
500 MHz反射式机械扫描声学显微镜的研究和试制   总被引:1,自引:0,他引:1  
本文叙述了500MHz反射式机械扫描声学显微镜的研究试制工作。介绍了显微镜的基本结构,分析和讨论了声透镜的分辨率和显微镜的实际分辨能力。测试结果证明该显微镜的分辨率已达2μm。文章最后给出一些样品的声学图像和声学特征曲线。结果说明它具有一些独特功能和广泛的应用前景。  相似文献   

7.
孔伟  郗传英  叶邦角  翁惠民  周先意  韩荣典   《中国物理 C》2004,28(11):1234-1237
研制了一套数字化的正电子湮没双多普勒展宽谱测量系统,用它测量了10个样品的双多普勒展宽谱,得到了一些有意义的结果.这些结果展示了一些金属单质材料的双多普勒展宽谱随着电子结构变化而发生的变化.本文简略介绍了双多普勒展宽谱仪,实验数据处理,以及这些金属单质材料的数据和分析结果.  相似文献   

8.
应用原子核的宏观-微观模型研究远离稳定线核的性质,得到了一些结果,例如质子和中子滴线,质子和中子密度分布及其均方根半径和中子皮厚度随同位素位移的变化.对一些奇异核性质的计算结果同相对论平均场方法计算的结果作了比较,对质子滴线附近核的质子放射性也作了简要讨论.  相似文献   

9.
应用原子核的宏观-微观模型研究远离稳定线核的性质,得到了一些结果,例如质子和中子滴线,质子和中子密度分布及其均方根半径和中子皮厚度随同位素位移的变化.对一些奇异核性质的计算结果同相对论平均场方法计算的结果作了比较,对质子滴线附近核的质子放射性也作了简要讨论.  相似文献   

10.
本文用扭曲波方法计算类H离子的电子碰撞激发截面,并给出ls→ns的截面计算公式和计算结果,文中不考虑电子交换。计算结果与发表过的一些理论结果作了比较。  相似文献   

11.
This review attempts to present the most salient developments of research on organic conductors and superconductors during the past 10 years. A theoretical introduction treats instabilities of quasi-one-dimensional electron systems and associated precursor effects which are relevant to the experimental results on organic conductors. We then describe the characterization of quasi-one-dimensional organic conductors by their transport, optical and magnetic properties. Finally, two sections are devoted to the experimental investigation of the low temperature instabilities: lattice instability in TTF-TCNQ and related compounds, superconducting or antiferromagnetic instabilities in the (TMTSF) 2 X series. The importance of one-dimensional fluctuations is emphasized in both lattice and superconducting instabilities.  相似文献   

12.
The generalization of the hard thermal loop effective theory to anisotropic plasmas is described with a detailed discussion of anisotropic dispersion laws and plasma instabilities. The numerical results obtained in real-time lattice simulations of the hard loop effective theory are reviewed, both for the stationary anisotropic case and for a quark-gluon plasma undergoing boost-invariant expansion.  相似文献   

13.
This review attempts to present the most salient developments of research on organic conductors and superconductors during the past 10 years. A theoretical introduction treats instabilities of quasi-one-dimensional electron systems and associated precursor effects which are relevant to the experimental results on organic conductors. We then describe the characterization of quasi-one-dimensional organic conductors by their transport, optical and magnetic properties. Finally, two sections are devoted to the experimental investigation of the low temperature instabilities: lattice instability in TTF-TCNQ and related compounds, superconducting or antiferromagnetic instabilities in the (TMTSF)2X series. The importance of one-dimensional fluctuations is emphasized in both lattice and superconducting instabilities.  相似文献   

14.
With the help of a set of exact closed-form solutions to the stationary Gross Pitaevskii equation, we compre-hensively investigate Landau and dynamical instabilities of a Bose-Einstein condensate in a periodic array of quantum wells. In the tight-binding limit, the anaiyticai expressions for both Landau and dynamical instabilities are obtained in terms of the compressibility and effective mass of the BEC system. Then the stability phase diagrams are shown to be similar to the one in the case of the sinusoidal optical lattice.  相似文献   

15.
C. M. Varma 《哲学杂志》2013,93(15):1657-1666
The cure to the ??=?1 Landau–Pomeranchuk instabilities in translationally invariant fermions is shown to be a state with an anisotropic gap at the Fermi surface. For higher ? and for fermions on a lattice, the general criteria for long-wavelength instabilities and their cure are found in terms of the derivatives of the single particle self-energy with respect to momentum for spin-symmetric instabilities and with respect to magnetic field for spin-antisymmetric instabilities. The results may be relevant to identifying hidden order parameters found in many metals.  相似文献   

16.
We derive in the Migdal-Eliashberg approximation new formulas for the free energy, entropy, and specific heat of conduction electrons coupled to phonons. Analytic results in terms of standard functions are obtained for Einstein phonons, and the calculation for realistic phonon spectra is reduced to simple, weighted integrals over Eliashberg's spectral function 2 F(). Our derivation requires a careful analysis of the range of validity of the Midgal-Eliashberg approximation which leads to some insight into the problem of lattice instabilities induced by a strong electron-phonon coupling.  相似文献   

17.
In this paper we review some recent results obtained on superconducting/ferromagnetic (S/F) structures when measuring the dynamic instabilities of the vortex lattice at high driving currents. The role played on the non-equilibrium properties of the hybrids by both the ferromagnetic and the superconducting materials has been analyzed with a special focus on the values and the temperature dependence of the quasiparticle relaxation times, τ(E). Knowledge of the relaxation mechanisms in these systems is extremely important in view of possible applications since it can drive the optimal choice of both materials to realize, in particular, ultrafast superconducting single photon detectors based on S/F hybrid structures.  相似文献   

18.
P. D. Semalty  Kapil Dev  P. N. Ram 《Pramana》2006,66(6):1077-1092
A detailed theoretical study of the low-temperature lattice specific heat of Ni-based dilute alloys has been carried out. Lattice Green’s function method has been used to calculate the local density of states of substitutional impurities and lattice specific heat in different alloys. The resonance condition has been investigated for possible occurrence of resonance modes. Except in NiCr and NiMn, low-frequency resonance modes have been obtained in all the alloys. However, no localized mode was obtained. The impurity-induced increase in lattice specific heat is explained on the basis of the obtained resonance modes. The calculation shows an excellent agreement with the measured lattice specific heat in these alloys  相似文献   

19.
NiAl的几何与电子结构   总被引:3,自引:0,他引:3       下载免费PDF全文
关键词:  相似文献   

20.
Motivated by the surge in research activities on graphene, we investigate instabilities of electrons on the honeycomb lattice, interacting by onsite and nearest-neighbor terms, using a renormalization group scheme. Near half band filling, critical minimal interaction strengths are required for instabilities toward antiferromagnetic or charge-density-wave order. Away from half-filling, f-wave triplet-pairing and d + id singlet-pairing instabilities are found to emerge out of density-wave regimes.  相似文献   

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