FeSiF66H2O晶体的基态能级和零场分裂参量

由单晶的中子衍射方法得到FeS_iF₆6H₂O的晶体结构,这种晶体结构可以用S_iF^6-和Fe(H₂O)⁺⁺两个离子来描述,而局域三角对称的Fe(H₂O)⁺⁺离子反映了这种晶体的主要光谱性质利用不可约张量的理论,构成了晶体场和自旋轨道相互作用哈密顿完全对角化矩阵因此,由完全对角化的晶体场和自旋轨道相互作用哈密顿矩阵和电子顺磁共振的理论公式来求出晶体FeS_iF₆6H₂O中Fe²⁺离子的电子顺磁共振零场分裂参量D和Fa并研究了低自旋³L态对电子顺磁共振(EPR)零场分裂参量的贡献结果显示低自旋³L态对电子顺磁共振的零场分裂参量的贡献是较强的理论计算的结果与实验值是相符的.     

Quadrupole splitting temperature dependence of high and low affinity deoxyhemoglobin encapsulated in wet silica gel

Hemoglobin (Hb) is still one of the most studied proteins due to its physiological function and because of its allosteric properties. It is actually well known that hemoglobin has at least two quaternary structures, one when the protein is fully oxygenated (R structure) and the other one when it is fully deoxygenated (T structure). In the last years, the encapsulation of hemoglobin in wet silica gel, preventing a change in the quaternary structure, gave the opportunity to show the existence of two T states: high affinity (HA) and low affinity (LA). Hb T state, in presence (LA) and in absence (HA) of allosteric effectors when it is encapsulated in wet silica gel, binds oxygen in non-cooperative way. Small differences between the quadrupole splitting values of HA and LA samples can be pointed out at low temperature regime. However, at present, these are too small differences to deduce that HA and LA Hbdeoxy states are different within the iron surrounding.     

Spin effects in a quantum ring

Recent experiments that are reviewed explore the spin states of a ring-shaped many-electron quantum dot. Coulomb-blockade spectroscopy is used to access the spin degree of freedom. The Zeeman effect observed for states with successive electron number allows to select possible sequences of spin ground states of the ring. Spin-paired orbital levels can be identified by probing their response to magnetic fields normal to the plane of the ring and electric fields caused by suitable gate voltages. This narrows down the choice of ground-state spin sequences. A gate-controlled singlet–triplet transition is identified and the size of the exchange interaction matrix element is determined.     

纳米量级超导Al粒子在磁场中的Zeeman分裂

用随机矩阵理论对BCS理论中的自洽方程进行修正.由此得到的新自洽方程能合理地描述纳米量级Al粒子的超导电性.更进一步论证在外磁场作用下,s>0态由于Zeeman效应得出了实验中已观测到的超导增强效应. 关键词： 纳米粒子 超导电性 Zeeman分裂     

Peak effect studies in single crystals CeRu2 and 2H-NbS2

We have studied the peak effect (PE) phenomenon in single crystals of weakly pinned superconductors CeRu₂ and 2H-NbS₂. 2H-NbS₂ is iso-structural and iso-electronic to 2H-NbSe₂, whose similarity with CeRu₂ as regards the PE representing the order-to-disorder transformation of the flux line lattice was claimed some time ago. We report on the step change in equilibrium magnetization across the peak effect in CeRu₂. We also present the vortex phase diagram of 2H-NbS₂ obtained from the magnetization data, and compare the PE phenomenon in 2H-NbS₂ and 2H-NbSe₂.     

Split fields and direction of propagation for the solution to first-order systems of equations

The standard wave-splitting approach for the wave equation in inhomogeneous media is first reexamined. Next, by analogy with the theory of wave propagation through singular surfaces, a characterization is given for a function in space-time to represent a wave propagating in a direction. The condition is applied in connection with a simple example and found to be quite restrictive. The same problem is then considered in the Fourier-transform domain where the unknown function is an n-tuple satisfying a system of ordinary differential equations. The condition for propagation in a direction is established for the Fourier components. Next, some physical problems are considered which are expressed by partial differential equations or by integro-differential equations. The associated first-order system of equations is examined in terms of the eigenvalues of a matrix. This shows that, for any eigenvalue, the direction of propagation may change with the frequency and that arguments about the dominance of the principal part of the operator may cease to hold.     

Circular flows of nearly Eulerian graphs and vertex‐splitting

The odd edge connectivity of a graph G, denoted by λ_o(G), is the size of a smallest odd edge cut of the graph. Let S be any given surface and ? be a positive real number. We proved that there is a function f_S(?) (depends on the surface S and lim_?→0 f_S(?)=∞) such that any graph G embedded in S with the odd‐edge connectivity at least f_S(?) admits a nowhere‐zero circular (2+?)‐flow. Another major result of the work is a new vertex splitting lemma which maintains the old edge connectivity and graph embedding. © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 147–161, 2002     

含Cr3+透明微晶玻璃的发光性能

选择若干玻璃组成，制得了含莫来石晶相的透明微晶玻璃，利用吸收光谱和室温荧光光谱对玻璃和微晶玻璃的发光进行了研究。研究表明，在一定测试范围内提高玻璃的晶化温度可以提高Cr^3 离子的有效发光效率；Cr^3 离子浓度的增加使微晶玻璃的发光强度增加，但引起浓度淬灭，降低Cr^3 离子的有效发光效率。对微晶玻璃荧光光谱中688nm发射肩的成因进行了探讨，提出了微晶玻璃荧光光谱中688nm和700nm发射可能由^2E能级分裂引起的观点。