十字叠层板横向剪切刚度的计算方法

本文研究了十字叠层板横向剪切刚度系数的计算方法.指出前人采用的横向剪应力为抛物线分布的假设不够准确,使C_ii的计算值产生误差.本文首先推导了横向剪应力沿厚度分布的计算公式,然后用幂级数拟合了近似权函数,用权函数法和能量法对两种铺层结构的碳/环氧十字叠层板的C_ii进行了计算.对比了两种方法的结果,并与文献[1]的方法作了对比.结果表明,对于对称层板本文权函数法与文献[1]的结果基本一致;而对于非对称叠层板,二者差别明显.能量法结果与权函数法对比,前者更精确.     

软X射线多层膜光栅

详细介绍了软X射线多层膜光栅的国内外发展概况和广阔的应用领域，全面分析了它的制作工艺，并指出制作多层膜光栅的关键技术及解决方案。     

Bombardment Induced Electron-Capture Processes at Sodium Halide Surfaces

Discrete features observed in the energy distribution of electrons emitted from ion-bombarded sodium halide surfaces can be attributed to a new type of collisional deexcitation mechanism. Such a mechanism involves sodium atoms in bombardment-excited autoionizing states that are the result of cascade collisions within the crystal lattice. This deexcitation process, in contrast to that for a metal, is not simply a consequence of the inner-shell lifetime of the initial collisionally excited sodium Na⁺* ion. Rather, the deexcitation consists of a sequence of lattice collisions during which the excited Na⁺* ion captures an electron to form the inner-shell-excited Na⁰* states responsible for the observed transitions. The formation of such autoionizing Na⁰* states is described within the framework of a new model in which excitation processes and localized collisional electron-transfer mechanisms are taken into account. These localized electron-transfer processes make possible new channels for electronic deexcitation, chemical dissociation, and defect production; they are critical for understanding inelastic ion-surface collisions in solids.     

利用数字技术进行激光横向光强分布分析的研究

本文介绍了利用数字技术进行激光横向光强分布分析的原理。并给出了具体的方案．实现了对激光横向光强分布图像进行锐化处理、生成光强分布的曲线、三维彩色图像及相关函数，并能进行高斯分布拟合检验．     

Gene therapy for malignant gliomas using replication incompetent retroviral and adenoviral vectors encoding the cytochrome P450 2B1 gene together with cyclophosphamide

Cyclophosphamide is an inactive prodrug which is converted by hepatic cytochrome P450 2B1 to cytotoxic metabolites which produce interstrand DNA cross-linking in a cell cycle-independent fashion. The limited ability of these metabolites to cross the blood-brain barrier contributes to the poor activity of cyclophosphamide against brain tumors. In this study we demonstrate that replication deficient retroviral and adenoviral vector-mediated gene transfer of cytochrome P450 2B1 into 9L glioma cells significantly increases the sensitivity of these tumor cells to cyclophosphamide in vitro, and prolongs the survival of animals bearing intracerebral 9L tumors treated with cyclophosphamide in vivo. Attempts to improve the effectiveness of retrovirally mediated transduction of the P450 2B1 gene by increasing the concentration of cyclophosphamide delivered to the tumors using intracarotid and intratumoral injections did not prolong animal survival, although survival was increased when a second treatment with P450-expressing retroviral vectors and cyclophosphamide was administered. These results suggest that in situ transduction of tumor cells with the P450 2B1 gene using retroviral and adenoviral vectors increases their sensitivity to cyclophosphamide and may have a potential role in the therapy of malignant gliomas.     

Hormonal and reproductive influences and risk of melanoma in women

Ratiometric images of cytoplasmic Ca2+ concentration ([Ca2+]c) in individual cells were recorded simultaneously with a confocal ultraviolet-laser microscope in the Indo-1-loaded islets isolated from mice. After changes in [Ca2+]c in response to glucose or amino acids were recorded, the islet was fixed, permeabilized, and stained by the indirect immunofluorescence method against insulin or glucagon in situ; the individual cells were then identified in the focal plain identical to that used for the [Ca2+]c imaging. Almost all cells identified as insulin-positive (beta-cells) by their distinct immunofluorescence responded to the increase in glucose concentration from 3 to 11 mmol/l with an increase in [Ca2+]c. Major populations of cells (approximately 65%) identified as glucagon-positive (alpha-cells) responded to the addition of arginine (5-10 mmol/l) to 3 mmol/l glucose solution with an increase in [Ca2+]c. About half of the alpha-cells (47.6%) responded to the addition of alanine (5-10 mmol/l) to 3 mmol/l glucose solution with an increase in [Ca2+]c. In contrast, <13% of beta-cells responded to the addition of alanine (5-10 mmol/l) or arginine (5-10 mmol/l) to 3 mol/l glucose with an increase in [Ca2+]c. More than one-fourth of alpha-cells responded with an increase in [Ca2+]c when glucose concentration in perifusion solution was reduced from 11 to 0 mmol/l. These results indicate that [Ca2+]c changes in islet cells stimulated by glucose or amino acid were characteristic of the cell species, at least in the alpha- and beta-cell. This technique provides a useful tool to investigate not only the intracellular signal transduction but also the intercellular signal transmission in the intact islet.     

在ZnO/Si衬底上ZnCdSe/ZnSe多量子阱的生长与光学特性

在经NH3等离子体氮化的Si(100)衬底上。用等离子体增强化学气相淀积(PECVD)的方法生长了ZnO缓冲层，经X射线衍射(XRD)测量，得到了单一取向的ZnO(0002)膜。在此ZnO缓冲层上利用低压金属有机化学气相淀积(LP-MOCVD)方法生长了较高质量的ZnCdSe／ZnSe量子阱。通过不同阱宽的ZnCdSe／ZnSe量子阱生长和测量，得到了多级共振拉曼峰。从发光谱中可见，在1520nm附近有很强的发光，而在未覆盖ZnO的Si衬底上直接生长的ZnCdSe／ZnSe量子阱结构，其光致发光(PL)谱未见发光。可见，在氮化的Si衬底上覆盖ZnO膜生长的ZnCdSe/ZnSe量子阱质量较好。是一种在Si衬底上生长Ⅱ-Ⅵ族化合物半导体材料的有效方法。     

球形与非球形颗粒反射膜后向散射特性的实验研究

本文报导了球形与非球形颗粒反射膜后向散射角分布特性。结果表明散射强度和角分布曲线与颗粒密度、颗粒尺寸和形状有关,选择合适的表面颗粒参数有可能控制其后向散射角分布特性。     

Tribological properties of aluminum alloy matrix TiB2 composite prepared by in situ processing

An investigation of the wear behavior, in lubricated sliding and rolling of in situ prepared TiB₂ particle-reinforced 2024 T4 Al alloy matrix composites against 52100 steel and hardened pearlitic nodular cast iron, respectively, was undertaken. In sliding contact, the 10 vol pct 0.3-μm TiB₂-metal matrix composite (MMC) showed slightly less wear than the 10 vol pct 1.3-μm TiB₂-MMC. Transmission electron microscopy of cross sections, taken normal to the wear track and parallel to the sliding direction, revealed that the TiB₂ particles on the wear track were polished and particle pullout was largely absent. This was attributed to the strong interfacial bonding between the Al-alloy matrix and the TiB₂ reinforcing phase. The TiB₂ particles on the wear track inhibited spalling. Subsurface damage of the MMC did not occur. The wear of the steel mating surfaces worn against the TiB₂-MMCs was minor and caused by the cutting action of the TiB₂ particles that resided on the MMC wear track. In rolling contact, the 0.3-μm-size TiB₂-MMC showed 5 times higher weight loss than the 1.3-μm TiB₂-MMC for the same content of reinforcement, but the weight loss of the cast iron mating surface was less for the former. For the smaller particle size, the wear of 5 and 10 vol pct TiB₂-MMCs was the same. A high density of surface cracks was present on the wear track of the 0.3-μm TiB₂-MMC but not on the 1.3-μm MMC. The significance of strong particle/matrix interfacial bonding and particle size effect on the wear behavior of ceramic particulate-reinforced MMCs in lubricated sliding and rolling wear is discussed.     

减一线油进常压塔回炼增产柴油

中国石化南阳石蜡精细化工厂采用减-线油进常压塔回炼技术。使常减压蒸馏装置柴油收率增加2．2％。全厂柴汽比提高0．14。工艺简单，成本低,效益佳。