关于具有负系数和缺系数的单叶函数

Let P_k(A,B) be the class of functions(?), regu-lar in the unit disc U={z:|z|<1} and satisfying |[f′(z)-1]/[A-Bf′(z)]|<1 for z∈U, where -1≤Bk(A,B) under the assumption -1≤B≤0. We also obtain class preserving integral operators of the form.     

Kinematic cuts and backward photoproduction

We present a phenomenological analysis of backward photoproduction in terms of the recently proposed kinematic cut model. The cut fills in the dip at u ≈ −0.15 without having to invoke the N_γ trajectory. Good agreement with the data is obtained in the scattering region; the extrapolation to the nucleon pole is unsatisfactory.     

Self-reflection of intense electromagnetic waves in plasmas

A uniform electromagnetic wave of high power density, propagating in a collisional plasma gives rise to a modification in temperature-dependent collision frequency and in turn induces a gradient in the complex refractive index of the medium. A WKB solution of the problem predicts a backward propagating wave on account of the self-induced inhomogeneity. The amplitude of the backward (i.e. reflected) wave increases with increasing power density of the wave. This is a volume nonlinear effect and is appreciable for usually employed power densities.     

Self-consistent theory of localization in weakly disordered systems

An analytic treatment of localization in a weakly disordered system is presented for the case where the real lattice is approximated by a Cayley tree. Contrary to a recent assertion we find that the mobility edge moves inwards into the band as disorder increases from zero.     

Reaction of sputtered Pt films on GaAs

Pt/GaAs interface reaction has been investigated between 250–500°C. Schottky barrier Impatt diodes for microwave applications with this structure have an operating temperature of ～250°C and the solid state reaction at the interface can lead to degradation of the device. Using RF sputtered Pt films on (100) GaAs, the reaction has been investigated with the help of X-ray diffraction, Auger spectroscopy, Rutherford backscattering and electrical resistivity measurements.The reaction starts by a rapid diffusion and dissolution of Ga in Pt and is slowed down by the formation of PtAs₂ at the interface which acts as a barrier for further Ga diffusion and reaction. Five different Pt-Ga phases and PtAs₂ were identified at various stages of the reaction. The final reaction products are PtAs₂ and GaPt. The reaction becomes self limited (up to 500°C) for Pt films thicker than ～2000 Å, probably due to extremely slow diffusion of Ga through the interfacial PtAs₂. Electrical resistivity data seem to indicate that Pt₃Ga is more resistive than PtGa which is the final equilibrium Pt-Ga compound observed in this reaction.     

The reaction of PPh3 with Di-μ-chlorobis(arylazooximato)dipalladium(II)

Summary Di--chlorobis(arylazooximato)dipalladiuni(II) compounds react with PPh₃ to give the four-coordinate complexes (5) and (4) in which the azooxime acts as a unidentate and bidentate ligand respectively. Hydrogen bonding in polar solvents such as MeOH or EtOHetc. stabilize (5) whereas, polar solvents such as Me₂CO, py and Et₂O convert (5) into (4). The equilibrium: (4) + PPh₃ (5) exists in PhH solution and equilibrium constants at 30°C have been calculated spectrophotometrically. The variation in equilibrium constants and the stabilities of (5) have been explained on the basis of electron-releasing and electron-withdrawing properties of substituents, R, in the azooxime ligand.     

Some solutions for Yang's equations for self-dual SU(2) gauge fields

It is shown that a large class of solutions of Yang's equations for self-dual SU(2) gauge fields can be obtained from the solutions of two-dimensional and four-dimensional Laplace equations.