超临界条件下吸热型碳氢燃料氧化安定性研究

采用超临界反应装置测定了吸热型碳氢燃料HDF-1的氧化安定性能．结合吸光度分析结果、红外谱图以及氧化沉积量的测定结果,考察了2,6-二叔丁基对甲酚（BHT）对燃料氧化安定性能的影响．结果表明,如果反应时间为3h,BHT能够将燃料的氧化沉积量降低64％,有效地提高燃料的氧化安定性能,但BHT对缓解燃料颜色变化并无明显效果．     

钢筋混凝土梁截面加固承载力分析

针对钢筋混凝土梁的截面加固问题进行了深入的受力分析，明确地论证了加固结构的受力性能与未经加固的普通结构有着显著的差别，并提供了计算公式。     

硅基稀土热扩散法初探

稀土元素在我国有丰富的贮量．近年来,稀土元素在各种新科技领域中得到不断的开发和利用．各类稀土功能材料在发光和光通信领域中正展现巨大的应用潜力［１］．稀土磁光薄膜材料是优良的记录介质;稀土Ｅｒ由于其特殊的电子结构,已用来制造掺铒光纤激光器和光纤放大器［２］;掺铒硅还可制造发光谱线单一的发光器件［３］,这为实现人们所期待的硅基光电集成提供了有益途径．此外,基于对掺铒硅荧光发射衰减时间的分析,可用于制造温度传感器［４］．因此,稀土在共价半导体材料如Ｓｉ、ＧａＡｓ中的行为研究日益受到重视．但这些工作主要…     

冲击压缩载荷下大尺寸混凝土力学响应的数值模拟

利用Ansys/Ls-dyna有限元软件模拟打击气压为0.6、0.8、1.2MPa下大尺寸混凝土的SHPB束杆试验. 试验结果表明, 模拟得到的冲击试验过程中束杆传播的入射、反射及透射应力波信号与实测结果比较, 波形总体吻合较好, 入射波偏差很小, 反射波和透射波差异略大; 打击气压越大, 试样破损速度越快. 数值模拟给出了不同打击气压下大尺寸混凝土破坏形貌变化的规律.     

十水硫酸钠体系潜热蓄热材料的研究

本文研究了 十水硫酸钠 体系潜热蓄热及其熔冻行为,并对熔化热的测定技术及计 算 公式进行 了研 究.该 蓄热材料经 15。。次熔冻循环后,蓄热客量仍在 30 C al·g一`以上.     

Lys121-Ile的定点突变对人尿胰蛋白酶抑制剂热稳定性的影响

为检验人尿胰蛋白酶抑制剂(UTI)两个结构域中的盐键的稳定性对UTI热变性可逆性的影响,将UTI中的Lys121突变成Ile以中断Glu69与Lys121之间形成的盐键,并命名为?UTI.然后对?UTI进行表达纯化和热解折叠实验.结果显示,?UTI在大肠杆菌中成功表达,纯化复性后经园二色谱测定三级结构与UTI基本相似,酶学测定表明恢复胰蛋白酶抑制剂活性.热变性实验表明:在pH低于7.4的缓冲溶液中?UTI的热解折叠是可逆的,与UTI的结果(pH<4.2)相比,pH值提高了3.结合以前对UTI在酸性条件下可逆热解折叠而在中性与碱性条件下不可逆热解折叠的机制的研究结果,认为多结构域蛋白解折叠的曲线除考虑各个结构域单独形成的多个S曲线的叠加外,还要考虑到结构域之间相互作用强度的影响.     

腔中捕获原子团间的纠缠态

利用单模腔场与捕获原子团的相互作用,提出原子团之间最大纠缠态的制备方案.数值上给出原子团间的纠缠度随白噪声强度的变化关系.计算出系统的热纠缠及其存在的临界温度.     

计及风和湍流的热晕及其相位补偿的数值研究

本工作用包括热晕、湍流和风等效应的等压近似下四维激光传输程序，数值计算了激光大气传输中的整束热畸变效应及其理想相位补偿，得到了各种情况下的激光大气传输畸变图象，并分析了热晕和湍流的相互作用。另外，还讨论了时、空步长的选取原则。     

MRI of thermally denatured blood: methemoglobin formation and relaxation effects

Focal regions of T₁-shortening have been observed in magnetic resonance imaging (MRI)-monitored thermal ablations of perfused tissues. The aims of this study were two-fold: to find evidence for heat-induced conversion of hemoglobin (Hb) to methemoglobin (mHb), and to investigate the effects of heat treatment of in-vitro blood components upon their MR relaxation times. Spectrophotometric studies were performed to confirm the heat-induced formation of methemoglobin. Preparations of whole and fractionated blood, previously submitted to elevated temperatures of 40°C to 80°C, were imaged and the relaxation times were calculated. Optical absorption spectra of samples containing free Hb, heated to 60°C, showed increased light absorption at 630 nm, evident of mHb presence. Short T₁ values in whole blood (1.13 s) and packed red blood cell (0.65 s) compartments, heated at 60°C, compared to their baseline values (1.62 s and 0.83 s, respectively), were attributed to mHb formation. In relation to MRI-guided thermal interventions, these results suggest a possible explanation for observation of hyperintense regions on T₁-weighted images.     

Residual stress/strain analysis in thin films by X-ray diffraction

Residual stresses are found in the majority of multilayer thin film structures used in modem technology. The measurement and modeling of such stress fields and the elucidation of their effects on structural reliability and device operation have been a “growth area” in the literature, with contributions from authors in various scientific and engineering disciplines.

In this article the measurement of the residual stresses in thin film structures with X-ray diffraction techniques is reviewed and the interpretation of such data and their relationship to mechanical reliability concerns are discussed.