PP/PE共混物的声发射和断裂行为

本文考察了不同共混比的 PP/PE 试样单轴拉伸时的声发射现象,探讨了共混比、拉伸速率对声发射的影响。用扫描电镜和光学显微镜观察了取向结构及微裂纹的形态,提出了这类共混物在拉伸时应力分布存在“趋表效应”、断裂是流变断裂的观点。     

岩石声发射特性的研究

本课题自1982年7月开始,至1986年7月结束。其中分为三个阶段:第一个阶段是准备阶段,对国内外的情况进行调研,建立本课题研究内容的测试系统,添置必须的仪器、换能器、刚性试验装置,进行测试系统的调试;第二阶段是室内实验,其目的在于研究应力应变全程曲线各阶段内的岩石声发射规律,用岩石声发射的多参数、多频率窗口变化规律探讨岩石试件破坏的机制,寻找岩体失稳最为可靠的参数,为现场岩体失稳预报建立坚实的理论基础;第三阶段是在牟定铜矿井下采场进行现场监测,其目的在于验证室内实验所获得的岩石声发射规律,并用这些规律去指导围岩稳定性监测,最后监测记录到了两次片帮事故。     

马氏体相变的微观理论—LASER模型 Ⅰ.基本概念和简单统计模型

提出马氏体相变的非平衡量子统计理论,考虑到了马氏体相变的特殊性:本身为远离热平衡相变,但马氏体相处热力学支。这需要合理应用激光物理、耗散结构理论、经典统计和量子体系的哈密顿动力学。本文建立一个简单的统计模型以说明电子-晶格强耦合体系的跃迁特征。非平衡统计部分由Master方程在声子表象中研究。导出的熵变式表明integral from n=path dS<0过程在形成粒子数反转中起关键作用,并示出在何种条件下,晶格原子跃迁特征由各个原子散乱跳越变为相干声子驱动的所有原子的协同跃迁。分折了马氏体相变的“声Laser”工作机理和激光阈的差别,并指出二者的基本原理一致。     

高容量泡沫式镍电极的研制

本文介绍了一种高容量泡沫式镍电极,确定了电极的工艺参数,考察了由其作为正极的圆柱密封氢镍电池的性能。     

Prediction of ammonia emission from dairy barns using feed characteristics part 1: Relation between feed characteristics and urinary urea concentration

Urinary urea concentration is an important predictor of NH3 emission from dairy barns. To reduce urinary urea concentration, accurate and precise prediction of urea concentration for different feeding regimes is a prerequisite. The objective of this research, therefore, was to predict urinary urea concentration of a cow using feed characteristics. To compute urinary urea concentration of a cow, we predicted: urine volume; urinary N excretion, using a regression or a mechanistic model; and the relationship between urinary urea concentration and urinary N concentration, which was derived from experimental data. Model results were validated using experimental data. Cows were fed one of nine diets, which was a combination of one of three rumen-degradable protein balances, and one of three roughage compositions. Each diet was repeated once. Measured parameters included herd, diet, and urine characteristics. Observed urinary urea concentration can be predicted with reasonable accuracy from existing models to predict urine volume and urinary N excretion using feed characteristics. The regression model predicted N excretion slightly better than the mechanistic model. In addition, input parameters required for the regression model are recorded at each dairy farm in The Netherlands. This regression model, therefore, can be used by animal nutritionists and producers to determine diets that result in a reduced NH3 emission.     

Effect of Change in Time of Acoustic Emission Attenuation in Rock Salt when Subjected to the Maximum Compaction

The effects peculiar to the acoustic emission during rock salt testing in the regime of evenly increasing strains and step-by-step change in loading are considered.     

YBa2Cu3O7 ? x 240 K Phase Transition

YBa₂Cu₃O_{7 – x} ceramic samples have been investigated simultaneously by the thermal expansion and the acoustic emission methods during thermocycling through 200–300 K into liquid nitrogen steam. No jumps in the dilatation curves but change in the slope of one has been found at 228 and 234 K on heating and cooling respectively. These points are accompanied by the acoustic emission signals, a small value testifying for oxygen atoms displacement into the crystal lattice. On the basis of these measured experimental data, a thermal expansion coefficient and a specific capacity c _m have been calculated. By this c _m value an oxygen atom activation energy E = 0.15 eV has been calculated. It is shown that an isostructural oxygen-displacement second-order phase transition takes place between certain orthorhombic phases in YBa₂Cu₃O_{7 – x} near 240 K.     

99mTc-MDP骨显像对兔股骨头缺血性坏死模型的实验研究

本研究是建立阻断股骨头动脉的股骨头缺血模型,通过分别阻断实验兔股骨头旋股内、外侧动脉,观察99mTc-MDP骨显像对于股骨头血流、代谢变化,及组织学改变.将实验兔分成三组:A组,结扎旋股内、外侧动脉;B组,结扎旋股内侧动脉;C组,结扎旋股外侧动脉.所有实验兔在术前均由耳缘静脉注入99mTc-MDP37 MBq,然后于术后两小时至八周应用SPECT检测实验侧股骨头(E头)、实验侧股骨干(E干)、对照侧股骨头(C头)、对照侧股骨干(C干)放射性计数,并计算比值和动态检测股骨头血流量及代谢的改变.结果是A组B组骨显像结果相同,手术当日及术后三日均可见兔实验侧股骨头放射性缺损,于术后一周开始出现放射性浓聚,至术后四周达高峰,术后八周仍有明显放射性浓聚,呈持续性高代谢反应状态.C组各时期三相骨显像结果与A、B组不同,手术当日可见兔实验侧股骨头放射性缺损,于术后三日即开始出现放射性浓聚,术后一周、四周均可见放射性浓聚,于术后八周即完全恢复.①E 头/C头比值:1.020±0.063,C头/C干比值:2.721±0.086.②A组和B组结扎旋股动脉术后两小时和三天E头/C 头和E 头/E 干比值明显下降,术后一周至八周血供重建,两组间无显著性差异(P＞0.05);③C组E 头/C 头和E 头/E干比值轻度下降,术后三天血供重建,比值增高不显著,与前两组之间均有显著性差异(P＜0.05).这说明:1.旋股内侧动脉及其分支为股骨头主要供血动脉;2.99mTc-MDP骨显像定量分析是评价ANFH的好方法.     

对一种利用液化天然气冷能实现零排放的能量系统的评估

该文对一种利用液化天然气（LNG）冷能实现有害气体零排放的能量系统进行了分析。该能量系统由利用LNG冷能的空气分离系统和动力系统两个部分组成。在空气分离系统中，利用LNG冷能作为补充冷量进行空气分离，可以使生产液氧的耗能降低60％-73．5％左右，同时使LNG汽化为天然气（NG）。在动力系统中，NG为燃料，氧气代替空气作为氧化剂。在整个能量系统中，燃烧产物仅仅为二氧化碳和水，其中二氧化碳气体可以通过液氧的冷能进行液化加以回收，从而实现能量系统有害气体的零排放。分析表明，该系统的效率约为37％，低于普通能量系统的效率，但是比同类的不采用LNG冷能的零排放系统的效率高一倍。     

计及环境成本的火电机组供电成本研究

由于我国排污总量收费制度的实施，火电机组的排污费用和燃料成本成为机组变动成本的一部分。在分析火电厂污染物排放的基础上，建立了包括排污收费环境成本在内的火电机组单位发电量成本模型，计算了特定情形下我国常见各类火电机组的计及环境成本的单位供电成本，并对燃料中硫和氮的质量分数变化对各类火电机组单位供电成本的影响进行了敏感性分析；分析了现行环保制度下各类机组存在供电成本差距的原因及应采取的对策。该研究对于正确理解各类火电机组的供电成本，促进环境保护和我国火电机组的竞价上网具有积极意义。