对高校基础课程考试考核制度改革的探究

考试考核历来被认为是教学过程中必不可少的重要环节。本文分析了高校基础课程考试考核存在的弊端,以人为本,围绕精英教育的理念,对基础课程考试考核制度改革的提出了几点建议,指出了考试方式及考核结果成绩评定应注意的问题。     

de Sitter-Schwarzschild正则黑洞的质量标量场扰动

采用数值计算方法对de Sitter-Schwarzschild正则黑洞在质量标量场微扰下的稳定性问题进行了探讨,并计算它在扰动下的似正则模和分析了它的性质。首先讨论了de Sitter-Schwarzschild正则黑洞的构型:具有de Sitter时空的中心,外部平滑连接Schwarzschild时空,并验证它的时空无奇性。然后计算黑洞时空中的质量标量场扰动方程,分析有效势的特性。之后再利用3～6阶WKB近似计算扰动的似正则模,计算结果表明:de Sitter中心相关的参数r₀²=3/Λ对质量标量场扰动下的似正则模影响很小;角量子数l对似正则模的作用与Schwarzschild黑洞相似;标量场的质量m²变化对似正则模的影响与Schwarzschild黑洞的情况有显著的不同,这也成为区分该黑洞与Schwarzschild黑洞的关键因素。     

The decoherence of quantum entanglement and teleportation in Bell-diagonal states

We study the dynamics of entanglement and teleportation in Bell-diagonal states. Using the concepts of concurrence and fidelity, the analytical expressions of the entanglement, the output entanglement and the average fidelity with decoherence are obtained for this model. We discover a class of initial states in which the output entanglement and the average fidelity are destroyed by decoherence. The quality of teleportation depends on the system parameters and time.     

DS/SS系统中Chip波形对系统抗单频干扰能力的影响

随着DS/SS系统的广泛应用。提高系统抗干扰能力一直是扩频通信研究的热点之一，扩频系统的处理增益作为衡量系统抗干扰能力的主要指标。通常等于单位数据比特内Chip的个数N。当系统受到强干扰时，系统的抗干扰性能会下降，首先分析了DS/SS系统的抗单频干扰能力。然后讨论了系统Chip波形对处理增益的影响，最后指出了系统Chip波形的幅度谱在零点处取值较小时可以获得大的系统处理增益。     

不同方向Dzyaloshinskii-Moriya相互作用和磁场对自旋系统纠缠和保真度退相干的影响

通过求解系统的Milburn方程,研究了包含Dzyaloshinskii-Moriya相互作用的自旋链系统中纠缠和保真度的动力学演化特性,讨论了不同方向Dzyaloshinskii-Moriya相互作用、不同方向均匀和非均匀磁场、不同初始态对纠缠以及保真度退相干的影响.研究发现,非均匀磁场的引入能够抑制纠缠退相干的发生,初始态的选择对系统纠缠状态的影响很大,可以通过调制Dzyaloshinskii-Moriya相互作用的方向来获得所需纠缠和较高的保真度.研究还发现,退相干条件下,无论是均匀还是非均匀磁场对于保真度的提高并不明显.纠缠和保真度随初始态角度的变化具有周期性,可以根据需要来选取不同系统中的最优初始态.     

Thermal Entanglement in Two-Qutrit Heisenberg XX Chain with Different Dzyaloshinskii-Moriya Interaction and Nonuniform Magnetic Field

The effects of the different Dzyaloshinskii-Moriya (DM) interaction on thermal entanglement of a two-qutrit Heisenberg XX spin chain in a nonuniform magnetic field are investigated. Our results imply that the x-component DM interaction plays a central role in enhancing quantum entanglement and it has a higher critical temperature than the z-component DM interaction. The entanglement can be tunable controlled by changing the multiple of the magnetic fields B1 and B2 . Also we found that different DM interaction are competitive to each other in some conditions.     

Entanglement in a two-qubit Heisenberg XXZ chain with different Dzyaloshinskii-Moriya couplings and an inhomogeneous magnetic field

Ground state entanglement and thermal entanglement of a two-qubit Heisenberg XXZ chain in the presence of the different Dzyaloshinski-Moriya interaction and inhomogeneous magnetic field are investigated.By the concept of concurrence,we find that the inhomogeneity of the magnetic field may make entanglement last for a long time and the critical temperature is dependent on Jz and b.The entanglement can be increased by increasing the temperature in some cases.We also find that the x-component parameter Dx has a higher critical temperature and more entanglement for a certain condition than the z-component parameter Dz.     

Effect of spin-orbit interaction on entanglement of two-qutrit Heisenberg XYZ systems in an inhomogeneous magnetic field

We investigate the properties of spin-orbit interaction in the ground state and thermal entanglement of a two-qutrit Heisenberg XYZ system in the presence of an inhomogeneous magnetic field. Using negativity as entanglement measure, we give the dependence of entanglement on each parameter in detail. The result shows that one can get appropriate entanglement by adjusting the magnetic field, Dzyaloshinskii-Moriya interaction and anisotropy parameter simultaneously.     

非均匀磁场和杂质磁场对自旋1系统量子关联的影响

通过负值度和测量诱导的扰动, 研究了非均匀磁场和杂质磁场对自旋为1的Heisenberg系统量子关联的影响. 研究发现非均匀磁场的增加会降低纠缠, 但也可用来产生纠缠, 并且会提高临界非线性作用K_c的值, 测量诱导的扰动的临界磁场要高于负值度的临界磁场, 而且测量诱导的扰动不会随着非线性作用|K| 的减小而消失, 它能全面反映量子关联的存在. 研究还发现, 不同杂质磁场对测量诱导的扰动的影响彼此间无交叉. 杂质磁场下, 相互作用|J| 必须小于非线性作用|K| 才会有纠缠存在, 但是测量诱导的扰动却可以在相互作用|J| 大于非线性作用|K| 时依然存在, |J| 与|K| 相同时只是测量诱导的扰动的最小取值点. 此外, 系统粒子数目对量子关联也具有重要影响.     

热敏电阻数字温度计设计制作实验的线性化方案探究

分析了半导体热敏电阻制作电子数字温度计的原理,对两种线性化设计方案及其实验结果进行了比较,对实验的教学进行了探讨.