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。     

强圆极化光对三能级原子寿命的影响

在薛定谔方程中引入能级衰减项,并通过对圆极化光调频及强激光近似,对三种类型的三能级原子分别找到了三个特殊态,基于对特殊态的研究,讨论了圆极化光对三能级原子寿命的影响.     

Phenomenological Connection Between Hadronic Wavefunction and Its Radius

A picture for the hadronic structure is discussed based on previous work^[1]. The radius contributed from the valence Fock-state wavefunction (i.e., qq component) is calculated in ~ the light-cone framework. We propose a concept of the characteristic length λ to represent the contributions of higher Fock states to hadronic radii phenomenologically and calculate its value. Using an equivalence between the "intrinsic" radii of constituent quarks and the radii coming from higher Fock states we put forward a constraint on the hadronic wavefunctions of mesons. It is found that these wavefunctions lead to consistency between theories and experiments for D and B exclusive decays. We also give the radii for K, D and B mesons. The results show that the radius of K meson is in good agreement with experimental data.     

Polaronic States Incorporating Effects of Phonon Confinement in a Rectangular Quantum Well Wire

The electron self-energy due to the interaction of the electron with the LO-phonon incorporating effects of phonon confinement in a rectangular quan tum well wire has been calculated as a function of the size of the wire by the perturbative method within the framework of the effective mass approximation. The results show that in a very smaU wire the self-energy has a peak at the beginning and then increases gradually to the two-dimensional limit value as the wire expands in one direction while keeping fixed in the other direction. The peak values are about at the square cross sections. For larger wires, the self-energy increases monotonically without appearing peaks and approaches slowly to the two-dimensional limit values. The results also present that the self-energy is related to the size of the cross section rather than to the cross sectional area of the wire, and the absolute values of the self-energies are lese than those in comparable two-dimensional quantum wells.     

Anomalous Vector-Boson Mass Generation on a Lattice

We show the vector boson mass generation on a lattice with the Wilson's fermion formulation. By calculating explicitly the change of the effective action under chiral transformation, it is also found an arbitrariness in the solution of the chiral Schwinger model, which depends on a lattice regularization in continuum theory.     

Beltrami Gauge Symmetry and 2D Induced Gravity

We introduce the Beltrami gauge symmetry related to the Beltrami parametrization of the metrics and the Beltrami equations. We explore its role in 2d induced gravity and show that Polynkov's. SL(R) and KPZ's residual symmetries are subsymmetries of the Beltrami gnuge symmetry in the light-cone gauge. We also find that the 2d induced gravity with or without matter can be reformulated as Beltrami-Liouville field theories on Riemann surfaces of higher genus.     

A Monte Carlo Study of Carrier Distribution in Yba2Cu3O7.

A Monte Carlo simulation has been carried out on the carrier distribution in the Ba-O plane of Yba₂Cu₃O₇, where the O-2p_z orbitals perpendicular to the plane are strongly hybridized with 3d_z² orbitals in adjacent Cu planes, while the in-plane O-2p_z and O-2p_y orbitals, which are nonbonding with respect to the Cu-3d orbitals, form two nearly degenerate subbands. The degeneracy is removed by the distortion of the lattice. A tight-binding Hamiltonian is constructed for such a coupled electronlattice system and the Monte Carlo simulation is made for a sample containing 35×35 unit cells with periodic boundary condition at various temperatures. Although the total number of carriers is fixed, the results show approximately a linear temperature dependence of in-plane hole density, and this is in good agreement with the Hall effect measurements. The distortion of the lattice is found to exhibit random character with some short range order. The relations to the other transport properties and to other superconducting oxides, especially the Nd-Ce-Cu-O systems, are also discussed.     

Study on KC1 Colorated Center Doped with Na+ Crystal by Positron Annihilation

The relation of the live times and S parameters with doped quantities of Na⁺ have been studied by positron annihilation method in pure,colourable and irradiant KC1 single crystals,The results show that the concentration of vacancies of KC1 doped with 800ppm Na⁺ is 4.24×10¹⁷/cm³.It is close to that of the pure KC1 crystal.The obvious F centers exist in the colorated crystal.The S parameters are mainly influenced by the external electrons of halide ions.Mechanism of annihilation of KC1 crystal doped with Na⁺ has been discussed.     

Shallow States of Donor Impurities at Defective Semiconductor Surfaces

Ground state energies for shallow states of donor impurities at certain idealized defective isotropic semiconductor surfaces are calculated variationally for GaAa surfaces with electrons confined within the semiconductor. Calculations show that impurity states with donor ions located at parts projecting out of surfaces have lower ground state energiea than those with ions located at parts sunk into surfaces.     

Calculation of Binding Energies of the Ground and Excited States of a Donor in GaAs-A1xGal-xAs Step Quantum Wells

In this paper we present for the first time completely analytical variational expressions for calculating the binding energies of the low-lying bound states of a hydrogenic donor in a quantum well (QW). These expressions can be used for the problem of the binding energy of an impurity in a general manner, e.g. for calculating the binding energies of a donor associated with subband states of any order in the QW with any arbitrary potential profile. 70 demonstrate the utilization of these expressions we have theoretically studied the binding energies for the ground and a few low-lying excited etates of a hydrogenic donor in a stepped quantam well (SQW). The variations of the binding energies for these donor etates with impurity positions are investigated for different heights of the step potential. The numerical calculation results show that the binding-energy curves in the SQW, in contrast to the case of the flat quantum wells (FQW's), exhibit a non-symmetrical structure relative to the center of the QW and depend on the sub-barrier potential. The peak position in the binding energy curves shifts away from the region occupied by the sub-barrier as increasing sub-barrier height. The maximum in the binding energies increases as the step potential increaaes. These effects can be interpreted by referring to the variation of the electron probability-density distribution and of the lowest subband in the SQW. The shape of the binding-energy curves related to the 2po-like state is different from the other states. It is associated with the particular feature of the wave function of the 2po state in the QW.