Conformational stability of factor VIIa: biophysical studies of thermal and guanidine hydrochloride-induced denaturation

The binding of the multidomain protein factor VIIa (fVIIa) to tissue factor provides the interprotein communication necessary to make fVIIa an efficient catalyst of the initial event in the extrinsic pathway of blood coagulation. We have investigated the stability of individual domains in fVIIa and the influence of Ca2+ and an irreversible active-site inhibitor (FFR-chloromethyl ketone). Equilibrium guanidine hydrochloride (GuHCl)-induced unfolding monitored by tryptophan fluorescence and far-UV circular dichroism (CD) demonstrated that the gamma-carboxyglutamic acid (Gla) domain unfolds at 0.3 M GuHCl and the serine protease (SP) domain at 3 M GuHCl and that Ca2+ is a prerequisite for the formation of an ordered, compact structure in the Gla domain. The loss of amidolytic activity coincides with the first transition, which is stabilized by the active-site inhibitor, and a change in the environment of the active site is demonstrated using a fluorescent inhibitor (DEGR-chloromethyl ketone). Thermal unfolding monitored by differential scanning calorimetry (DSC) reveals that Ca2+ stabilizes the SP domain slightly, increasing the unfolding temperature by 2.7 degrees C. In addition, Ca2+ is required for a large enthalpy change concomitant with unfolding of the Gla domain, and this unfolding enthalpy is only detectable in the presence of the SP domain, indicating some kind of interaction between these domains. Thermal unfolding measured by CD indicates secondary structural changes at the same temperature as the heat absorption in the DSC but only when both the Gla domain and the SP domain are present together with Ca2+ ions. Taken together, these results indicate a Ca2+-dependent interaction between the Gla domain and the SP domain, implying a high degree of flexibility of the domains in free fVIIa. It is also shown that the epidermal growth factor-like domains are stable at elevated temperatures and high GuHCl concentrations. Moreover, already at physiological temperature, subtle structural changes take place which influence the overall shape of fVIIa and are detrimental to its enzymatic activity.     

高韧性—70℃低温钢WHD4（09MnNiDR）的性能及应用

本文研究了武钢研制生产的高韧性—70℃低温钢WHD4(09MnNiDR)钢板的全面力学性能、焊接性能.介绍该钢在大型石油、化工设备中的应用实例.结果表明该钢具有优异的低温韧性和优良的焊接性能,是制造低温压力容器等设备的理想用材.     

双相位共轭镜的工作条件参数分析

本文讨论了纯扩散机制的光折变晶体用作单作用区的双相位共轭镜（ＤＰＣＭ）时的阈值耦合强度和允许的输入光强比范围，并与双作用区的情况进行比较后，给出了在输入光强比远离１的条件下，双相位共轭镜的正常工作的条件参数。     

测量高功率激光的体吸收能量计

叙述了体吸收激光能量计的特点，介绍了其标定方法，给出了其技术参数。体吸收激光地的推广应用取得了广泛的社会效益。     

SiH4＋CH4激光等离子体动力学时空特性

采用时间，空间分辨的等离子体光辐射诊断技术，研究了脉冲ＴＥＡＣＯ２激光诱发ＳｉＨ４＋ＣＨ４击穿产生的等离子体膨胀过程，得到不同空间位置，不同实验条件下等离子体发光的时间特性，证明了ＳｉＨ４＋ＣＨ４气体击穿产生爆燃波而后诱发激波是等离子体中基本宏观动力学过程，并在实验上分析了激波对等离体内化学反应的影响，为激光等离子体合成ＳｉＣ粉末微观反应动力学过程的研究提供了参考数据。     

Actor模型的继承机制研究

Ａｃｔｏｒ模型是一种面向对象的并发模型，但它缺乏对继承机制的支持。本文试图阐明在Ａｃｔｏｒ模型中该支持什么样的继承以及如何支持这种继承。     

Mechanical properties of Al2O3 particle-Y-TZP matrix composite and its toughening mechanism

Dense Al₂O₃ particle-Y-TZP matrix (Al₂O₃<40 vol%) composite was prepared by pressureless sintering at 1550°C. Composites with 10–30 vol% Al₂O₃ particles showed enhanced fracture toughness, bending strength and Vicker's hardness as compared to single-phase Y-TZP. The highest strength (1150 MPa) and highest toughness (12.4 MPa m^1/2) were obtained for the composite containing 10 vol% Al₂O₃. It was found that, in addition to the contribution by the crack-deflection effect, the enhanced phase transformation from tetragonal to monoclinic during fracture was the main toughening mechanism in operation in the composites.     

A minimum cost assessment method for composite generation andtransmission system expansion planning

Composite generation and transmission system expansion analysis should take into account both economic considerations and adequacy requirements. An optimum expansion plan should achieve the minimum total investment, operation and damage cost. A minimum cost assessment method for composite system expansion planning, which can be used to consider generation expansion and transmission expansion simultaneously, is presented. The minimization model proposed to incorporate both operating and outage costs can recognize different customer damage functions at different load buses and includes the duration of the simulated contingency system states . A computer program based on the presented method has been developed to provide a set of line, load bus, generator bus and system indices which can be used to select optimal expansion plans at different load growth levels. Case studies in which the method is applied to the IEEE Modified Reliability Test System indicate its effectiveness     

新型后坐加速度开关阵列传感器

分析了国外后坐加速度传感器发展动向。介绍了新型后坐加速度开关阵列传感器的结构、原理、参数选择和性能设计。给出了原理性静态、动态试验结果，以证明新方案的可行性。最后指出了这种新型结构的传感器所具有的特点。