Transverse momentum distribution of lepton-pairs in Drell-Yan process in an asymptotically free scalar field theory

The transverse momentum dependence of the parton distribution function and the Drell-Yan cross section is studied in detail in the asymptotically free scalar field theory in six dimensions. In the context of the renormalization group approach of Collins, particular attention is devoted to the transition between the small q_T formula (due to multe-quanta effects) and the large q_T formula (due to single hard-quantum emission). The calculation represents a case study of the application of the renormalization group method and provides a guide to the corresponding study in QCD.     

Characteristics of thin gate dielectric in a rapid thermal processing machine and temperature uniformity studies

Rapid Thermal oxidation (RTO) of silicon has been investigated in the temperature range 1000° to 1250°C for an oxidation time of 5 to 60 s. The fairly extensive kinetics data show that linear growth occurs with an activation energyE _a of 1.4 eV. Rapid thermal nitridation of SiO₂ (96 Å) has been performed at three different temperatures: 1150°, 1200°, and 1250°C for a nitridation time up to 150 s. The characteristics of both materials have been investigated by capacitance-voltage, current-voltage, high resolution transmission electron microscopy and Auger spectroscopy. The results will be discussed with special emphasis on breakdown field statistics. The influence of Rapid Thermal Annealing (RTA) on the characteristics of both oxide and nitrided oxide will also be presented. A simulation model of a rapid thermal processing machine is presented with particular attention to the formation of slip lines. The theoretical results are in good agreement with those obtained experimentally.     

Determination of branching distribution by concurrent GPC and sedimentation velocity experiments

A method of determining the distribution of branching in polydisperse polymer samples is proposed. This method uses data from concurrent gel permeation chromatography and sedimentation-velocity experiments. Tedious fractionation, which must precede other methods of determining long-chain branching, is eliminated. An example of use of the method on the data of a sample of styrene–divinylbenzene copolymer is given.     

QCD asymptotics and kinematic thresholds in deep inelastic scattering

The Nachtmann moments of deep inelastic scattering structure functions are required by kinematics to contain a so far neglected threshold factor which is dependent on both n and q². Its presence significantly affects the “moment analysis” in the usual QCD phenomenology and it resolves the difficulties connected with improper threshold behavior of the “ξ-scaling” analysis of structure functions.     

Random grafting statistics in graft distribution analysis

Graft distribution functions have been derived from random grafting statistics. Among the functions, the weight fraction of ungrafted backbone chains, the molecular weight distribution of the ungrafted backbone chains and the GPC apparent molecular weight distribution of the graft copolymer have been found to agree with experimental values determined for a graft copolymer system in which grafting was expected to be random. The other functions, which are not directly measurable, are therefore probably also correct. In analytical work the entire set of graft distribution functions may be computed for a graft copolymer system from the following experimental data: (1) molecular weight distribution of the starting backbone chains; (2) the chemical composition of the mixture of the graft copolymer and ungrafted backbone; (3) the graft side-chain molecular weight distribution, which may be assumed to be identical to that of the ungrafted homopolymer separable from the reaction mixture.     

Determination of long-chain branching in model polystyrene samples by the GPC-sedimentation method

The GPC–sedimentation velocity method proposed earlier for the determination of long-chain branches was examined quantitatively by using model star-shaped and comb-shaped polystyrene samples of known degree of branching. The results showed that separation by sedimentation velocity was more sensitive to branching variations than separation by GPC. The results showed also that at low and moderate levels of branching the GPC–sedimentation velocity method reflected accurately the amounts of branching in the model samples. At high levels of branching, the method underestimated the amount of branching. The discrepancy, however, appears to have been caused by the inadequacy of the theories used in the interpretation of the raw data and not by any inherent problem in the method itself. The relative sensitivities of the GPC-sedimentation, GPC-viscosity, and GPC–light scattering methods are discussed.     

The observation of abnormal signals in laser flash photolysis: a type of probable synchronized nuclear spin signals

In laser flash photolysis (LFP) work, noise-like signals were observed together with transient absorption decay spectra in time domain. Analyzed results show that it is a valuable resonance spectrum of excited state molecules, in which four molecular cases are given here. We proposed that this kind signal might originate from nuclear or nuclear and electron spin resonance features in the excited molecules based on radio wave frequency spectrum levels and the significant interaction with static magnetic field.