Increased Vulnerability to Stress Following Opiate Exposures: Behavioral and Autonomic Correlates.

The authors used rats to study the impact of a history of opiate exposures on behavioral and autonomic responses to restraint stress. Brief restraint (30 min) provoked tachycardia and a pressor response, anxiety (as indexed by social interaction), grooming, and reduced exploration. The pressor response was reduced at 1 day, but not 7 days, after last opiate exposure; tachycardia was unaffected (Experiment 1). Stress-induced anxiety was potentiated 1 and 7 days after last opiate exposure (Experiment 2), and this potentiation was a function of dose (Experiment 3) and duration (Experiment 4) of opiate exposure. The results show that a history of opiate exposures alters vulnerability to stress and has implications for understanding coping, anxiety, and emotionality in former opiate users. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

输电线路边界保护中雷电冲击与故障的识别

输电线路的边界保护原理是在单端利用暂态分量中包含的高频分量是否经过线路边界这一特点构成的 ,当雷电冲击线路时 ,会使边界保护发生误动作。通过大量的仿真分析 ,发现在雷电冲击没有造成短路和造成弧光短路以及普通短路故障情况下 ,由于线路两端的避雷器造成暂态分量的小波谱随着时间的变化规律不同 ,并提取这一差别构成了雷电和短路的识别算法。输电系统的仿真模型采用频率相关模型 ,ZnO避雷器采用IEEE公认的频率相关模型。EMTP仿真验证说明了该算法的正确性。     

分子自组装体系的影响因素及其在纳米材料中的应用

介绍了分子自组装体系的影响因素以及分子自组装技术在纳米材料制备方面的应用,并对聚合物自组装体系及研究进展作了综述.     

电子自旋共振波谱法检测含骨类食品的初步研究

电子自旋共振(Electron spin resonance,ESR)波谱测定是检测含骨类食品自由基的有效方法之一.本工作研究了辐照诱导的含骨类食品的ESR波谱特征、样品制备方法及辐射剂量-效应关系.结果表明,辐照前后ESR波谱图形、g因子和△H皆有明显差异,据此很容易区分辐照与未辐照含骨类食品样品;冷冻干燥和磨碎是样品制备过程中的关键步骤;吸收剂量(0.3-10.1kGy)与ESR信号强度有良好的线性关系;ESR信号的相对强度还与动物种类有关.这为制定我国含骨类辐照食品的ESR检测方法标准提供了依据.     

新疆东天山灵北地区康南岩体岩石学#br# 特征及其构造意义

研究区位于新疆东天山觉罗塔格造山带吐哈盆地以南百灵山以北,多年来对于研究区古生代构造背景的认识受前人热议,存在争议。通过对研究区新发现基性岩体的岩石、地球化学特征与构造背景进行探讨,以期为大区域构造背景的研究提供一定的数据支持。主量元素研究表明,康南岩体具有高Mg、Fe,低Al的特征,说明研究区基性侵入岩为碱性岩石系列。微量元素测试结果表明具有同源演化的特征,Rb、Hf元素亏损较为严重。K、Ba、P、Sm富集明显,Tb、Nb、Ti表现为弱异常,在稀土元素球粒陨石标准化配分模式图中Eu的负异常不明显,表现为弱的正异常, Yb+Nb-Rb构造环境判别图解中样品落在“后碰撞”环境内,以上特征说明具有岛弧花岗岩的基本特征。岩性为深灰绿色弱蚀变细粒橄榄辉绿岩。     

Rheology, phase morphology, mechanical, impact and thermal properties of polypropylene/metallocene catalysed ethylene 1-octene copolymer blends

Blends of a polypropylene (PP) and a metallocene catalysed ethylene-octene copolymer (EOC) were prepared using a single screw extruder fitted with a barrier screw design. The EOC used had 25 wt% 1-octene content and the weight fraction of EOC in the blends covered the range 1-30 wt.% Viscosity values for the blends determined experimentally from dual capillary rheological studies were similar to those calculated theoretically using the log additivity principle described by Ferry. This result together with scanning electron microscopy (SEM) observations and evidence from tan δ curves from dynamic mechanical thermal analysis showed PP and EOC to be partially miscible for blends having 10 wt% EOC or less. The tensile modulus, break strength and flexural modulus of the blends decreased with respect to virgin PP as the weight fraction of EOC was increased to 30 wt.% The diminution in mechanical properties was concomitant with an initial increase in elongation at break from 40% for neat PP to 140% for the blend with 15 wt% EOC before decreasing to 65% when 30 wt% EOC was blended. The optimum impact modification of the PP used in this study, in the temperature range −40 to 23 °C, was achieved by blending with between 20 and 30 wt% EOC.     

深井破碎围岩条件下煤巷锚杆构件合理配套

基于徐州矿区张小楼井24302工作面运输平巷的地质条件，在深井破碎围岩条件下进行了煤巷锚杆支护试验，介绍了锚网带索支护技术参数和不同构件配合支护的巷道矿压显现．根据顶板锚杆螺母撕裂和穿过托板与钢带导致的锚杆支护失效问题，在实验室完成了锚杆、托板、钢带和螺母等支护构件配合的力学性能试验．试验表明：直径20mm的螺纹钢锚杆杆体性能稳定，破断载荷均在186kN，杆体和螺母的螺纹配合完好，顶圆底四方螺母能与托板和钢带很好地配合，外接圆直径为38mm的六方螺母与托板和钢带不能很好地配合．深井高应力破碎围岩条件对锚杆支护系统中的锚杆、锚固剂、托板、钢带和螺母等构件的力学性能配合要求高，它们的力学性能应基于锚杆的破断力合理配套．     

尾盐水兑卤试验研究

对钾肥生产车间排出的高钾含量尾盐水进行了回收钾的兑卤试验,结果表明,在高温季节按7∶1～8∶1的比例兑卤,可满足工艺回收钾的要求.     

Polyethylene multiwalled carbon nanotube composites

Polyethylene (PE) multiwalled carbon nanotubes (MWCNTs) with weight fractions ranging from 0.1 to 10 wt% were prepared by melt blending using a mini-twin screw extruder. The morphology and degree of dispersion of the MWCNTs in the PE matrix at different length scales was investigated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM) and wide-angle X-ray diffraction (WAXD). Both individual and agglomerations of MWCNTs were evident. An up-shift of 17 cm⁻¹ for the G band and the evolution of a shoulder to this peak were obtained in the Raman spectra of the nanocomposites, probably due to compressive forces exerted on the MWCNTs by PE chains and indicating intercalation of PE into the MWCNT bundles. The electrical conductivity and linear viscoelastic behaviour of these nanocomposites were investigated. A percolation threshold of about 7.5 wt% was obtained and the electrical conductivity of PE was increased significantly, by 16 orders of magnitude, from 10⁻²⁰ to 10⁻⁴ S/cm. The storage modulus (G′) versus frequency curves approached a plateau above the percolation threshold with the formation of an interconnected nanotube structure, indicative of ‘pseudo-solid-like’ behaviour. The ultimate tensile strength and elongation at break of the nanocomposites decreased with addition of MWCNTs. The diminution of mechanical properties of the nanocomposites, though concomitant with a significant increase in electrical conductivity, implies the mechanism for mechanical reinforcement for PE/MWCNT composites is filler-matrix interfacial interactions and not filler percolation. The temperature of crystallisation (T_c) and fraction of PE that was crystalline (F_c) were modified by incorporating MWCNTs. The thermal decomposition temperature of PE was enhanced by 20 K on addition of 10 wt% MWCNT.