火灾中考虑整体性的钢梁破坏形态研究

1990年英国broadgate火灾之后,结构整体性以及由于温度而在整体结构中产生的附加应力得到了人们的重视。处于整体结构中的梁的破坏形态与单个构件的梁的破坏形态有较大差别,当考虑梁的悬链线效应时其抗火承载力明显提高。文章采用大型通用有限元程序ANSYS,对T.C.HLiu所做试验进行了验证,表明了有限元计算悬链线效应的可靠性,同时通过计算分析,提出了处于整体结构中钢梁在火灾中破坏的5个阶段,并给出了钢结构防火的概念设计建议。     

Environmental damage costs in Iran by the energy sector

On the basis of the energy supply and demand, this paper assesses the environmental damage from air pollution in Iran using the Extern-E study that has extended over 10 years and is still in progress in the European Union (EU) commission. Damage costs were transferred from Western European practice to the conditions of Iran by scaling according to GDP per capital measured in PPP terms.     

基于神经-模糊推理系统的机械设计数据处理

针对机械设计领域中所存在的大计算量、多图表问题,应用一种神经-模糊推理系统进行映射辩识,以提高计算速度和编程处理能力,消除知识的"组合爆炸"现象。通过对具体数据、图表的实际应用表明,应用这种方法能够很好地表达原图表数据关系。同时,相对于单纯应用人工神经网络方法,它的数据识别精度更高,速度更快,能够满足设计计算要求。     

Single-sided ventilation — Part II. further considerations

This paper extends an earlier report of measurements and computer predictions of flows in a cubical cavity exposed on one side to the scavenging effect of an external stream. Further measurements and photographs are presented; they are consistent with each other and with the predictions of the computational model. Specifically, comparisons are made between measured and predicted mean velocities and turbulent shear stresses, and photographs are used to elucidate features of the shear layers generated by accelerating and decelerating external flows. The computer model is used to deduce approximate relations between internal turbulent activity (measured by mean velocity, turbulence energy and shear stress) and external velocity, percentage ‘window’ opening and relative position of the plane walls upstream and downstream of the cavity.     

硫对注入YSZ单晶的金属铂在退火过程中结晶的影响

秀卢瑟福背散射－沟道技术（ＲＢＳ－Ｃ）和Ｘ射线衍射技术（ＸＲＤ）研究了Ｐｔ和注入ＹＳＺ（Ｙ２Ｏ３稳定的ＺｒＯ２）后产生的损伤和退火过程中损伤的恢复及注入Ｐｔ的晶化，ＲＢＳ－Ｃ分析表明ＹＳＺ室温下的存在较强自退火效应，ＸＲＤ分析结果示出硫以铂的晶化产生很大影响。     

固铍处理几种工艺方法讨论

近年来,贵溪冶炼厂贫化电炉渣含铜呈逐年上升趋势,究其原因较多,其中在贫化电炉中处理固铍是主要原因之一.文章主要是时贵溪冶炼厂固铍处理生产现状进行介绍,对贵冶固铍处理的几种可能方法进行分析和讨论,并进行相应的技术经济比较.     

基于电子鼻系统的番茄苗不同种类损伤的区分效果研究

通过对早疫病病害番茄苗、灰霉病病害番茄苗、机械损伤番茄苗和对照番茄苗的电子鼻响应信号的对比,可以看出不同处理的番茄苗样本电子鼻的响应信号是不同的,表明用电子鼻响应信号对番茄苗不同种类损伤进行预测是可行的.从PCA结果来看,早疫病病害的番茄苗和灰霉病病害的番茄苗能很好区分开,机械损伤的番茄苗和正常处理的番茄苗产生了重叠现...     

原发性高血压病靶器官损害的预测仿真研究

研究原发性高血压病靶器官损害准确预测问题,由于原发性高血压病靶器官损害的影响因子之间存在着高度冗余和非线性,导致传统方法预测准确率低,为提高预测精度,构建了一种改进的基因表达式编程算法的原发性高血压病靶器官损害预测模型,首先设计了适合靶器官损害预测的适应度函数,然后为克服早熟现象提出了以平均适应度形式自适应的改变重组算子概率和变异算子概率,通过数据训练得到靶器官损害的2年预测模型。采用对山东中医药大学第二附属医院原发性高血压病历史数据进行验证性仿真,结果表明,方法的预测精度更高,在原发性高血压病靶器官损害的预测中有着广泛的应用前景。     

表面n沟CCD的电离辐射损伤

本文报道了150光敏元表面n沟CCD(电荷耦合器件)在不同能量电子和γ射线辐照后的电离辐射效应。试验结果表明,转移失效率在≤10Gy时已明显增大。但大多数器件在累积剂量≤50Gy时,通过调整“胖零”注入仍可工作。在高剂量辐照期间,不同栅偏压器件的转移效率退化存在较大差异。应用高频和准静态C-V技术分析了参数退化的原因。     

Surface characterization of 6H-SiC (0001) substrates in indentation and abrasive machining

Surface characterization of 6H-SiC (0001) substrates in indentation and abrasive machining was carried out to investigate microfracture, residual damage, and surface roughness associated with material removal and surface generation. Brittle versus plastic deformation was studied using Vickers indention and nano-indentation. To characterize the abrasive machining response, the 6H-SiC (0001) substrates were ground using diamond wheels with grit sizes of 25, 15 and 7 μm, and then polished with diamond suspensions of 3 and 0.05 μm. It is found that in indentation, there was a scale effect for brittle versus plastic deformation in 6H-SiC substrates. Also, in grinding, the scales of fracture and surface roughness of the substrates decreased with a decrease in diamond grit size. However, in polishing, a reduction in grit size of diamond suspensions gave no significant improvement in surface roughness. Furthermore, the results showed that fracture-free 6H-SiC (0001) surfaces were generated in polishing with the existence of the residual crystal defects, which were associated with the origin of defects in single crystal growth.