基于Apollo信号控制台的NQR炸药探测方法

介绍了一种基于Apollo信号控制台的核四极矩共振（NQR）炸药探测方法，描述了系统的结构组成、工作原理和实现方法，并给出了对RDX的测试试验结果. 试验表明该方法可实现对RDX信号的探测.     

The Modeling of Velocity Enhancement in Polymer Flooding

In single-phase polymer flooding experiments it has repeatedly been observed that the average velocity of the polymer molecules is higher than the average velocity of the water molecules. This effect is incorporated in many conventional Enhanced Oil Recovery (EOR) simulators by the introduction of a constant velocity enhancement factor. In this paper we show that, in absence of dispersion, a constant enhancement factor in the mathematical model for two-phase polymer flow (Buckley--Leverett displacement) leads to ill-posedness of the model equations. We propose a saturation dependent enhancement factor, derived from a model based on percolation concepts, for which this problem does not occur.     

基于正弦灰度变换的X光图像增强

介绍了灰度变换法的几种形式 ,提出了一种正弦非线性变换法 ,对三幅数字X光医学图像进行了处理 ,获得了令人满意的对比度增强效果 ,证明该方法有效而实用     

Dynamic response of permalloy/Cu/Co magnetoresistive sandwiches

The dynamic response of trilayer magnetoresistive permalloy/Cu/Co films was studied by high-frequency permeability spectra measurements. The resonance frequency is shown to depend on the interlayer copper thickness. This dependence is related to exchange coupling between permalloy and cobalt and the interaction field is estimated using the Landau–Lifschitz–Gilbert model.     

Individual and center-of-mass resonances in the motional spectrum of an electron cloud in a Penning trap

We have examined experimentally the motional spectrum of an electron cloud confined in a Penning trap. When the axial oscillation is excited by a radio frequency field the resonance exhibits a double structure. Both components depend differently on the number of trapped electrons and have different shape and width. We conclude that one of them corresponds to the excitation of the individual electrons while the other is the center-of-mass mode of the cloud. The threshold behaviour of the center-of-mass resonance suggests that it is a parametric instability of a Mathieu type equation of motion. Received 11 July 2001 and Received in final form 12 November 2001     

Organic SIMS with single massive gold projectile: Ion yield enhancement by silver metallization

The yield of CN from glycine rises from one CN per projectile impact to two when the sample is covered with a nominally 1 nm thick layer of silver. These yields were obtained for bombardment with Au₄₀₀⁴⁺ projectile with 136 keV impact energy. A multitude of CN-based clusters, e.g. Ag_xO_y(CN)_z are produced concurrently. As a result, a total of three CN-based secondary ions are generated per projectile impact. The exceptionally high yield for CN is of interest for biological SIMS.     

Optimization of the synthesis of non-symmetrical alkyl dimethyl sulfonium halides

This work is aimed at the optimization of the yield and purity of non-symmetrical trialkyl sulfonium halide salts. The effects of parameters such as solvent, temperature and concentration were studied. The products were carefully analyzed and the crystal structure of [{n-CH₃(CH₂)₁₅}(CH₃)₂S]Br determined. The overall aim of the present study is future syntheses of low-dimensional magnetic materials.     

低温等离子体对塑料表面处理——低温等离子体对高密度聚乙烯表面处理的ESR研究

本文研究了不同处理条件(处理功率、处理时间和处理压力)下等离子体气体(Ar、N₂、O₂和空气等)对高密度聚乙烯表面处理产生的自由基的ESR谱。我们观察到等离子体处理产生的自由基是相当稳定的,它的ESR信号强度随处理功率和处理时间增加而增加。但处理压力对它影响不大。我们证明了紫外线对高密度聚乙烯表面产生自由基作用随处理条件而变化。并初步解释了谱的超精细相互作用。     

Novel radical‐responsive MRI contrast agent based on paramagnetic liposomes

A novel, radical responsive MRI contrast agent based on a gadolinium chelate conjugated to a liposome through a disulfide linker was synthesized, with the aim of pursuing the in vivo mapping of radicals. The liposome was prepared by incorporating a thiol‐activated phospholipid, which was subsequently reacted with a gadolinium chelate containing a free thiol group. The long reorientational motion of the supramolecular adduct endows the paramagnetic agent with a relaxivity significantly higher than that of the free complex. The disulfide bond represents a radical‐sensitive moiety and a large decrease in contrast efficacy (T₁ relaxivity) is shown upon its cleavage. A preliminary assessment of the system was made by means of in vitro gamma‐irradiation and thiol–disulfide bond exchange with dithiothreitol. Both methods showed a clear dose‐dependent decrease in T₁‐relaxivity. Copyright © 2003 John Wiley & Sons, Ltd.     

EPR investigations of oxidation effects in (V1−xMox)2−δO3

Electron paramagnetic resonance (EPR) investigations has been carried out on the new family of molybdenum doped vanadium sesquioxides (V_1−xMo_x)_2−δO₃. The oxidation effects were monitored from the rate of paramagnetic V⁴⁺ created when the sample is exposed to the air. The effects of the oxidation time, sample temperature, and annealing at 1000 °C under a diluted hydrogen atmosphere on the EPR signal features are analyzed. The V⁴⁺ concentration in the oxidized samples is determined and the relaxation effects driven by the conduction electrons are pointed out from the thermal behaviour of the EPR line features. EPR spectra of all the oxidized samples also reveal a small ferromagnetic contribution strongly correlated with the V⁴⁺ content.