Experimental observation of interaction of runaway electrons with lower hybrid waves in slide-away regime in the HT-7 tokamak

The characters of slide-away regime in the HT-7 tokamak have been investigated, and evidences that lower hybrid waves (LHW) are excited in slide-away regime are presented based on local fast electron bremsstrahlung (FEB) emission profile and FEB emission spectrum. The interaction of high energy runaway electrons with those excited LHW via anomalous Doppler resonance is analyzed and the resonance energy is derived with which the behavior of those relevant signals in the experiment can be explained very well. It is shown that this interaction can provide an effective way to reduce the damage to the machine caused by runaway electrons.     

Superconducting and excitonic quantum phase transitions in doped Dirac electronic systems

We investigate the effect of superconducting and excitonic interactions, as well as their competition, on Dirac electrons on a bipartite planar lattice. It is shown that, at half-filling, Cooper pairs and excitons coexist if the superconducting and excitonic coupling parameters are equal and above a threshold corresponding to a quantum critical point. In the case where only the excitonic interaction is present, we obtain a critical chemical potential, as a function of the interaction strength. Conversely, if only the superconducting interaction is considered, we show that the superconducting gap displays a characteristic dome as charge carriers are doped into the system. We also show that, as the chemical potential increases, superconductivity tends to suppress the excitonic order parameter.     

Reactive EB Processing of Polymer Compounds

Polymer modification with high energy electrons is well-established in polymer industry and used for degradation, cross-linking, grafting, curing, and polymerization. These applications use local and temporal precise input of energy in order to generate excited atoms or molecules as well as ions for subsequent molecule changes via radical induced chemical reactions. Reactive electron beam (EB) processing combines melt mixing process and chemical reaction simultaneously. For this purpose, a 1.5 MeV electron accelerator was directly coupled to an internal mixer in order to induce chemical reactions by energy input via high energy electrons under dynamic conditions of melt mixing of different polymer compounds. In the present study, reactive EB processing was used for the development of a flame retardant polyethylene composite as well as Thermoplastic Vulcanizate. The influence of absorbed dose as well as electron energy and electron treatment time was studied. Increased values of both tensile strength and elongation at break of polymer compounds indicated in-situ compatibilization upon reactive EB processing.     

金刚石薄膜质量的拉曼光谱与红外光谱判定

根据ＤｉＤｏｍｅｎｉｃｏ公式并采用计算机模拟计算了金刚石薄膜中的ｓｐ２／ｓｐ３键价比，计算中不仅考虑了ｓｐ３相及ｓｐ２相拉曼线１３３２ｃｍ－１，１５８０ｃｍ－１，同时考虑了“Ｄ”线１３５５ｃｍ－１存在，这一计算给出了金刚石薄膜质量的定量评估方法。当金刚石薄膜质量较高时，由于仪器灵敏度限制，其拉曼光谱中显示不出ｓｐ２相宽带结构情况下，无法采用拉曼光谱判定薄膜质量。在此情况下，本文提出了藉助于红外光谱计算有效电子数ｎｅｆｆ从而相对评估金刚石薄膜质量的判断技术     

Plasmon dispersion in metallic lithium–ammonia solutions

Inelastic X-ray scattering spectra of lithium (Li)–ammonia solutions with concentrations of 9, 13, and 17 mol.% metal have been measured with 0.05- and 0.38-eV resolution for momentum transfer between 0.18 and 0.56 Å⁻¹. The peak growing with Li-concentration was found around 2 eV, and was assigned to the plasmon of delocalized Li-2s electrons. The plasmon shows a positive dispersion, indicating that exchange–correlation effects in actual nearly free electrons are considerably smaller than expected.     

From solvated electrons to metal anions: Electronic structure and dynamics

The techniques of magnetic susceptibility and magnetic resonance (NMR, ESR) have proved to be invaluable in the study of the electronic structure and dynamics of both paramagnetic and diamagnetic species in solutions of metals in non-aqueous solvents. This paper contains a brief review of recent experimental work in this area, concentrating on localized excess-electron states ranging from solvated electrons, electron-cation encounter species, through finally to gas-like metal anion species existing in these non-aqueous solutions. Throughout, the emphasis is on the information gleaned from magnetic measurements about the microstructure and environment of these matrix-bound states.Session lecture, Ninth International Conference on Non-Aqueous Solutions, Pittsburgh, PA, August 1984.     

日冕磁流管中的离子回旋不稳定性与电子加速

本文结合数值计算,给出日冕条件下发生回旋不稳定性的条件。经分析得到离子回旋不稳定性较电子回旋不稳定性优先发生的结论,并讨论由离子回旋不稳定性所产生的电场和加速电子流。     

Some relations of the diffusion constant of latent tracks in polymers and the ion energy loss

Measurements of the diffusion constant and the permeability of ion irradiated Makrofol KG (polycarbonate) sheets have been done with Argon and Nitrogen as diffusion gas. The polymers were irradiated at the “Gesellschaft für Schwerionenforschung” (GSI, Germany) with Uranium and Gold ions with energies of about 10 MeV/nuc. The fluence varies from 3·10⁹ to 4·10¹¹ ions/cm². For the irradiation the material was put together in stacks with layers of 8 μm thickness. This allows to relate a definite amount of energy loss to each layer and to examine the dependence of the diffusion constant and the permeability on it. For comparison electron irradiated and pristine material (i.e. the untreated material) were also measured.

The general tendency shows an increase of the diffusion constant and the permeability with growing energy loss up to a certain limit. In case of the highest energy loss the material changes its appearance and the diffusion constant and the permeability values are remarkable lower than those of the pristine material. A first trail of explanation might give the three-zone-model presented in this paper.     

Electro-optical phenomena accompanying electron and hole heating in superlattices and quantum wells GaAs/AlGaAs and Ge/GeSi

New electro-optical phenomena in quantum-well structures, i.e. modulation of the light absorption and birefringence due to carrier heating in a strong electric field, have been investigated. The effects have revealed different features in the three types of structures under investigation, namely: (1) well-dopedn-type GaAs/AlGaAs multiple quantum wells, (2) barrier-dopedn-type GaAs/AlGaAs superlattices and (3) barrier-dopedp-type Ge/GeSi multiple quantum wells. Possible mechanisms of the phenomena have been discussed.