FORMATION AND MAGNETIC PROPERTIES OF A NOVEL Gd3(Fe,Ti)29Ny NITRIDE

The novel Gd₃(Fe_0.978Ti_0.022)₂₉ compounds and their nitride have been synthesized. The X-ray diffraction patterns of the Gd₃(Fe,Ti)₂₉N_y and its parent compounds were indexed in the Nd₃(Fe,Ti)₂₉-type structure with a monoclinic symmetry and space group P2₁/c, Both the nitride and the parent compounds exhibit ferrimagnetlc coupling. Nitrogenatio led to an increase in Curie temperature and saturation magnetization. The Curie temperatures are 517K for the parent and 765K for the nitride. The saturation magnetizations σ_s at 4.2K are 101.9A·m²/kg for the parent and 128A·m²/kg for the nitride. Both the nitride and parent exhibit a planar anisotropy. Nitrogenation led to a decrease of the contribution of Fe-sublattice to planar anisotropy. The anisotropy fields at 4.2K are 9.8T for the parent and 6.5 T for the nitride.     

界面耦合对共聚物能带及键结构的影响

建立了紧束缚近似下的二嵌段共聚物-(A)x-(B)y-的物理模型,研究了组成共聚物的均聚物间界面相互作用-界面耦合的强弱对共聚体系的能带结构、键结构性质等的影响.共聚物的带隙也可通过改变均聚物之间的界面相互作用来加以调制,进一步发现可用界面势阱或能垒(energy barrier)来表征界面耦合的强弱.     

反应N(2D)+H2→NH+H和N(2D)+D2→ND+D的立体动力学理论研究.

基于Ho等人的精确势能面(J. Chem. Phys. 119, 3063(2003))研究,运用准经典轨线方法计算了21.3 kJ/mol碰撞能下反应N(²D)+H₂→NH+H和N(²D)+D₂→ND+D的产物与反应物之间的矢量相关．发现两个反应的产物角分布都是前向和后向呈现峰值分布,产物的转动角动量矢量j′不仅是取向的,而且是在y轴负方向上定向的．两个反应显示出的同位素效应主要归因于同位素质量的差别．     

Entanglement for Two-Qubit Extended Werner-Like States： Effect of Non-Markovian Environments

We investigate the sudden birth and sudden death of entanglement of two qubits interacting with uncorrelated structured reservoirs. The system is initially prepared in two-qubit extended Werner-like state. We work out the dependence of the entanglement dynamics on both non-Markovian environments and the purity of initial state, and show that non-Markovian environments and the purity can control the time of the two-qubit entanglement sudden death and the reservoirs＇ entanglement sudden birth. Furthermore, under the conditions of different purity and initial entangIement, the revival of qubits＇ entanglement can manifest before, simultaneously or even after the disentanglement of their corresponding reservoirs.     

Entanglement in One-Dimensional Random XY Spin Chain with Dzyaloshinskii--Moriya Interaction

The impurities of exchange couplings, external magnetic fields and Dzyaloshinskii-Moriya （DM） interaction considered as Gaussian distribution, and the entanglement in one-dimensional random XY spin systems is investigated by the method of solving the different spin-spin correlation functions and the average magnetization per spin. The entanglement dynamics at central locations of ferromagnetic and antiferromagnetic chains have been studied by varying the three impurities and the strength of DM interaction. （i） For the ferromagnetic spin chain, the weak DM interaction can improve the amount of entanglement to a large value, and the impurities have the opposite effect on the entanglement below and above critical DM interaction. （ii） For the antiferromagnetic spin chain, DM interaction can enhance the entanglement to a steady value. Our results imply that DM interaction strength, the impurity and exchange couplings （or magnetic field） play competing roles in enhancing quantum entanglement.     

在电磁学体系下讨论运动电荷的电场与磁场的联系

本文以点电荷相对导体圆环运动为例，在麦克斯韦电磁理论的体系下，阐明导体圆环系下电场与磁场之间的联系，以揭示电磁场的相对性。     

Sobolev方程的连续时空有限元方法

本文研究Sobolev方程的连续时空有限元方法.首先建立Sobolev方程的连续时空有限元格式,然后证明了解的存在唯一性和稳定性并给出连续时空有限元解各种范数下的误差估计.最后给出数值算例来验证理论分析的正确性,并进一步说明本文所建立的格式关于时间可以得到比传统有限元方法更高的精度.     

半导体激光器圆波导的低耦合损耗机制分析

设计了一种具有圆对称波导的半导体激光器,利用有限差分-光束传播法(FD-BPM)研究了半导体激光器圆波导的远场图象(FFP)与波导参量的关系,并分析了光纤与半导体激光器低损耗耦合机制.     

对乙酰基偶氮氯膦与镧显色反应的研究及应用

研究了对乙酰基偶氮氯膦与镧的显色反应 ,在 0 .2 mol/L 盐酸介质中 ,有乙醇及吐温 - 80存在时 ,生成3∶ 1紫色络合物。 λmax=6 75 nm,ε=7.33× 1 0 4 L· mol- 1· cm- 1。采用双波长法 ,以 5 30 nm为参比波长 ,6 75 nm为测定波长 ,ε=9.2 0× 1 0 4 L· mol- 1· cm- 1 ,镧含量在 0— 37.5 μg/2 5 m L范围内符合比耳定律。本法用于电子工业钛酸镧烧结中游离氧化镧的测定 ,结果令人满意。     

电化学方法分析铅阳极膜的相组成

本文提出使用线性电位扫描和电位衰退定性和定量分析铅在4.5mol·dm^-^3H2SO4(30℃)中形成的阳极膜的相组成并与现场X射线衍射, 原子吸收光谱, 阳极溶出等法比较。结果表明电位扫描伏安曲线的峰电位和电位扫描至峰电位左右时电极开路后, 所得的稳定电位可用于阳极膜相组成的定性分析, 电位扫描伏安电线电流峰的面积可用于阴极膜相组成的定量分析。本文的阳极膜由PbO·PbSO4, PbO2和PbOn(2>n>1)组成, 以PbO·PbSO4为主要成份。