On the theory of the Kondo effect in two-dimensional metals

The Kondo effect in a (quasi-)two-dimensional metal is studied. The special feature of the two-dimensionality is the Van Hove singularity in the electron density of states. For the band filling choosen such, that the Fermi level is close to the saddle points of the band spectrum, the Van Hove singularity comes into play and changes the usual Kondo log to the log². It turnes out to be possible to carry out the first order parquet summation and to obtain the conditions for the Kondo antiferromagnetic resonance for an arbitrary geometry of the band spectrum. The connection with the Orthogonality Catastrophe is traced and it is shown, that the weak coupling Kondo problem just corresponds to the intermediate asymptotics of the metal's relaxation in a time-dependent external potential.     

Diffractive production of ρ-mesons and of ρπ-systems by neutrinos and antineutrinos on protons

Evidence is presented for diffractive production of -mesons and of -systems invp and chargedcurrent interactions. In the (anti-)neutrino energy range 10 GeVE _v <60 gev=" the=" cross=" sections=" for=" diffractive="> and diffractive production are found to be (0.64±0.14 (stat.)±0.08 (syst.))% and (0.28±0.08 (stat.)±0.04 (syst.))% of the charged-current cross section. The diffractive signal is consistent with being entirely due to diffractivea ₁ production. However, the data cannot distinguish between diffractivea ₁ and diffractive nonresonant production. The experimental distributions ofW, Q ²,x _Bj andy _Bj for diffractive and events are consistent with model predictions.     

激光等离子体能量角分布及吸收定标律

主要研究激光平面靶等离子体发射能量角分布及吸收定标律。实验利用高斯型1.06μm激光脉冲,其能量为2～50J,脉冲宽度为0.3～2.2ns,靶面平均辐照强度为1.8×1013～1.1x10~(15)W/cm~2,光束以25°角入射。实验采用了Au、Ag、Ti、Al和C_8H_8等厚靶。用等离子体卡计测量靶面吸收的激光能量。用指数函数拟合实验数据,给出了吸收效率分别作为激光强度、脉冲宽度和靶材料原子序数的函数的定标关系式。这些关系式定性地与逆轫致吸收的理论关系式相一致。     

超软X射线流气式正比计数管

介绍了一种用于测量183～933eV超软X射线的圆柱形、侧窗式、流气式正比计数管,工作气体是0.11MPa的P-10气体或氦气-丙烷混合气体。计数管内径为φ25mm,直径为φ0.3mm的入射窗是由厚度80～90μgcm~2聚乙烯甲醛制成的。该计数管的特点:(1)薄窗,对软X射线透过率高。(2)流气式,工作寿命长。(3)能量分辨率好。(4)计数率高(1×10~(14)个/s)。(5)可测能区宽(0.183～10keV)。(6)可以方便更换窗膜材料、厚度及窗口直径。近几年来该计数管已经为高强度低能X光源提供较好监测。     

电子束相空间分布效应的三维计算

在386微机上建立了长脉冲单模的三维放大器数值模拟程序3DFEL,每个单程只需20分钟。模拟计算得出:(1)发射度对输出功率的影响几乎是指数式的。(2)电子相空间形状(相同发射度)对输出功率的重大影响主要表现为两方面:(a)不同相空间形状,等效能散度是不同的,(b)电子束包络和光场包络匹配关系。(3)非理想入射(偏入射和斜入射)超出一定范围之后将引起输出功率的指数下降。     

类He的Y离子双电子复合计算

采用准相对论的多组态Hartree-Fock(HFR)方法计算了类Li的Y离子(Z=39)的能级和振子强度,并且通过采用扭曲波方法计算自由电子的波函数,我们得到了由类He的基态到类Li的双激发态的自电离几率和双电子复合系数。在计算中,相对论质量—速度和Darwin修正都包含在哈密顿中。为了便于等离子体细致能级占据数密度的动力学计算,我们用一个解析表达式来表示作为自由电子温度函数的双电子复合速率系数,这个表达式精确地描写了从类He的基态到类Li的单激发态的双电子复合。     

Investigation of the molecular motion of spin-labeled lysozyme in solution by the use of ESP spectra and electron spin relaxation

The theory of electron spin relaxation in protein solutions taking into account the “two-motion” model of spin label mobility is developed. The relations obtained for the longitudinal and transverse relaxation rates describe the experimental results better than isotropic (“one-motion”) model. The mechanism of longitudinal relaxation in solution of spin-labeled lysozyme is revealed and the correlation time of the inherent motion of spin label is evaluated. The linewidth analysis and study of ESR spectra under viscosity variation were used to obtain the microdynamical parameters characterizing lysozyme molecular mobility. A discrepancy between the correlation time values obtained by viscosity-variation-technique and the results known from other methods is found and ascribed to the manifestation of the intermediate time-scale mobility of protein.     

Investigation of the photothermally modulated ferromagnetic resonance signal from magnetostatic modes in yttrium iron garnet films

The conventional and photothermally modulated (PM) ferromagnetic resonance (FMR) of magnetostatic modes (MSM) in yttrium iron garnet (YIG) films have been investigated as a function of temperature. Approaching the ferrimagnetic transition at T _c=560 K a strong enhancement of the PM-FMR signal amplitude is observed which is accompanied by a change of the signal shape. The observations are discussed in the framework of a model that takes into account the temperature derivatives of those quantities that contribute to the high-frequency susceptibility. At temperatures still below T _c a paramagnetic line emerges. The MSM disappear in a state of finite magnetization which is explained on the basis of damping of the MSM being important in the vicinity of the magnetic phase transition. Additionally, frequency and power dependent measurements are presented and the imaging ability of PM-FMR is demonstrated.     

Ablation of an optically homogeneous absorbing medium by scattered pulsed laser radiation

We have studied the ablation of an aqueous CuCl₂ solution in a pulsed Nd:YAG laser field featuring a speckle-patterned structure characterized by spatial radiation energy fluence fluctuations. This leads to a nonuniform distribution of the energy absorbed in the bulk of the sample being irradiated and causes local overheating centers to form, wherein ablation is observed to take place at laser energy fluences below the threshold value found in experiments with a homogeneous laser beam. This effect should be manifest in the laser irradiation of biotissues which, as a rule, scatter light strongly.     

Experimental study of acoustic probing of electrical space charge in solid insulators

Experimental results are presented on acoustic probing of electric fields in solid insulators. An experimental apparatus and methods are described for acoustic measurements of the bulk space charge density and electric field strength in solid insulators. The sensitivity and spatial resolution of the acoustic probe technique are determined.Institute of Introscopy Research, Polytechnical University, Tomsk. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 62–67, September, 1993.