Refocused primary echo: A zero dead time detection of the electron spin echo envelope modulation

We report on the two-dimensional (2D) implementation of the refocused primary electron spin echo envelope modulation (ESEEM) technique, its theory and experimental application to a model system and a system of biological interest. This technique is virtually free of dead time along one time coordinate. The ESEEM obtained by integration of the 2D time-domain data of the refocused primary ESEEM over one of the time coordinates shows the intensity of the sum combination harmonics proportional to k² for k 1 and proportional to k for k 1 (k is a usual notation for the modulation amplitude factor). This feature, in combination with the adjustment of k by means of variation of the operational frequency of the spectrometer, was found to be very useful for detection of protons with distributed hyperfine interaction parameters situated close to the electron spin.     

Causal Green's function formalism in statistical mechanics of composite particles

A causal Green's function formalism is established within the framework of statistical mechanics of composite particles. It is shown that it provides a systematic way for calculating shift and broadening of atomic levels in partially ionized plasmas.     

Determination of an Absorbed Radiation Dose by the EPR Method from the Concentration of the Centers Produced

A method to determine the absorbed radiation dose that is based on the spin-resonance dosimetry is suggested. It rests on the fact that under irradiation additional centers that absorb UHF radiation are generated in substance. This leads to a change in the time of longitudinal relaxation of a Zeeman subsystem and dipole-dipole reservoir as well as in the time of transverse relaxation because of the dipole-dipole interaction, which in turn causes a change in the shape of the line and in the saturation parameter. It is possible to determine the minimum absorbed dose at which the minimum deformation of the shape of the line is registered. A method is also suggested to determine an absorbed dose in the absence of absorbing centers in the substance before irradiation. __________ Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 3, pp. 335–338, May–June, 2005.     

A kinetic theory of spectral line shapes

The methods of kinetic theory are used to describe the radiation from an atom immersed in a gas of perturbing particles. It is shown that the line shape can be expressed in terms of a one-particle distribution function. The appropriate BBGKY hierarchy of equations is derived. This hierarchy is then truncated by assuming that only two-body collisions are important. The resulting equations are solved to obtain a non-Markovian kinetic equation which describes the combined effects of Doppler and pressure broadening. When the Markovian assumption is applied, a generalized linear Boltzmann equation is obtained which describes the line shape in the region where the impact limit is valid and which also describes the phenomenon of collisional narrowing.This research was supported in part by the Advanced Research Projects Agency of the Department of Defense, monitored by Army Research Office-Durham under Contract No. DA-31-124-ARO-D-139.     

Model for infrared and Raman studies of molecular rotations in liquids and gases

Experimental infrared and Raman data for molecular rotations in dense phases often lie in between the results predicted by theJ- andM-diffusion models of Gordon. In this paper, we present a theory which is similar in its basic approach to Gordon’s extended diffusion models (EDM) but in which the restrictions of theJ andM limits are removed. The outcome is a scheme which allows one to describe situations which fall between the two extreme pictures of theJ andM models. Application of this scheme to experiments is discussed.     

快速造P(n,k)大表的左肩法则和斜线法则

设Ｐ（ｎ,ｋ）为整数ｎ分为ｋ部的无序分拆的个数,每个分部≥１,它为大师欧拉所建立（１７０７－１７８３）．它是组合图论和数论里最重要的数据之一．然而,它却十分难于计数和造表．本文,由公式Ｐ（ｎ,ｋ）＝Ｐ（ｎ－１,ｋ－１）＋Ｐ（ｎ－ｋ,ｋ）定义了Ｐ（ｎ,ｋ）的左肩数和锐角数,并由此得到求Ｐ（ｎ,ｋ）的左肩法则（第一法则）．还根据本文作者［５］的一些重要定理得到求 Ｐ（ｎ,ｋ）的斜线法则（第二法则）．使用这些法则得到造Ｐ（ｎ,ｋ）大表的有趣原理．为方便计,我们仅用第一法则设计了计算机程序,用此程序即可快速造出任意大的Ｐ（ｎ,ｋ）表．     

Evaluation of the Intensities of Spectral Lines under the Influence of Interferences and the Determination of Global Maxima of the Mass–Spectrum Peaks

We describe the technique by which the intensity of spectral lines can be evaluated and the global maxima of the mass–spectrum peaks under the influence of pulse interferences can be defined using an experimental setup based on a commercial MX–7304A mass spectrometer, IBM personal computer (PC), and a digital extremum regulator that allows one to ignore local extrema and bring about automatic search for a global maximum of the mass–spectrum peak and its tracking with an accuracy of 0.0012% at a speed of response of 50 kHz, elevated speeds of the scanning of masses 500 amu/sec, and stability of regulation.     

Flow analysis of the weld line formation during injection mold filling of thermoplastics

To study the weld line formation of colliding flow fronts the filling of a mold cavity was simulated. The thermo-rheological findings were used to investigate the sources of weld line weakness. In this way critical areas of the interface in regard to the lack of interdiffusion and the inappropriate molecular orientation were found to be placed near the surface of the finished parts. The main source for the weld line weakness seems to be the V-notch that arises due to the poorly bonded region near the surface in combination with the large shrinkage as a result of extremely high molecular orientations induced at the end of the filling. Furthermore, the empirical knowledge was confirmed that weld lines are rather more sensitive to the local flow situation than the global processing conditions. Melt and mold temperatures can be considered to be the most important factors which influence the weld line strength.In part presented at the 6th European Conference on Rheology, Erlangen, 2002     

p-Adic multi-zeta values

Let X be the projective line minus 0,1, and ∞ over . The aim of the following is to give a series representations of the p-adic multi-zeta values in the depth two quotient. The approach is to use the lifting of the frobenius which is not a good choice near 1, but which gives simple formulas away from 1, and to relate the action of frobenius on the de Rham path from 0 to ∞ and on the one from 0 to 1. Also some relations between the p-adic multi-zeta values of depth two are obtained.