工程数据库的双缓冲区管理机制

提出了一面向对象数据库系统Ｏ２Ｓ的双缓冲区机制，阐述了页面缓冲区和对象缓冲区的管理数据结构及其缓冲区内的废品回收等，双缓冲机制能有效地提高应用对象的访问效率。     

传动方案设计专家系统的智能模型与关键技术

分析了传动方案设计的特点，探讨了如何利用人工智能理论及专家系统与常规ＣＡＤ技术解决传动方案设计问题。并给出了智能模型的建立及知识表示、约束推理、参数设计、多方案设计与布置设计的原理与方法。     

用Ω展开方法讨论化学体系的涨落

运用ＶａｎＫａｍｐｅｎ提出的Ω展开方法，对两个化学反应系统：进行了研究，建立了这两个反应系统组分浓度的一阶矩和二阶矩。     

大坝变形信息判据与分析

应用概率统计原理，对水库大坝变形观测中的变形值与随机因素干扰建立了变形数学模型。为排除干扰，提取真正变形信息，正确判据和分析大坝变形状态与规律提供理论依据。该数学模型在水库的实际应用中获得良好效果。     

求解k阶线性递归方程组的一种更有效的并行算法

将求解ｋ（ｋ≥２）阶线性递归方程组问题转化为求矩阵序列部分积问题，在ＳＩＭＤ共享存储模型上提出了求解ｋ阶线性递归方程组的一种新的有效并行算法．研究表明，本算法的加速和效率比现有算法均有较大的改善．     

使过半数规则具有传递性的偏好断面的规模

证明了当ｎ＞３时，使过半数投票表决的结果具有传递性的个人偏好序的最大数目大于２￣（ｎ－），从而否定了Ｃｒａｖｅｎ猜想。文中给出了最大偏好序的递推公式以及确定相应约束集的三条规则。     

Analysis of the relationship between age of larvae at mutagen treatment and frequency and size of spots in the wing somatic mutation and recombination test inDrosophila melanogaster

The relationship between the induction of mutant clones and the time of mutagen treatment was studied in the somatic mutation and recombination test (SMART) in wing cells ofDrosophila melanogaster. Larvae trans-heterozygous for the recessive marker mutations multiple wing hairs (mwh) and flare (flr) were produced. Batches of these larvae were then treated with mutagen at different ages spanning all three larval instars. Methyl methanesulfonate was fed acutely for 2 h by immersing the larvae in a solution of the mutagen mixed with powdered cellulose. Wings of the surviving adult flies were mounted and scored for the presence of spots. The frequency and size of single and twin spots were recorded separately. Twin spots are produced exclusively by mitotic recombination, whereas single spots can results from various types of mutational and exchange events. There exists a clear correlation between time of induction and frequency as well as size of the single spots. In young larvae only few but very large spots are induced, whereas in older larvae the frequencies are considerably increased but the sizes are smaller. The twin spots show a different relationship. Practically no twin spots are found in very young and in very old larvae. The results demonstrate that in the wing spot test the optimal age of the larvae for mutagen treatment is 72 h.     

Active sliding between cytoplasmic microtubules

Microtubules are versatile cellular polymers that play a role in cell shape determination and mediate various motile processes such as ciliary and flagellar bending, chromosome movements and organelle transport. That a sliding microtubule mechanism can generate force has been demonstrated in highly ordered structures such as axonemes, and microtubule-based force generation almost certainly contributes to the function of mitotic and meiotic spindles. Most cytoplasmic microtubule arrays, however, do not exhibit the structural regularity of axonemes and some spindles, and often appear disorganized. Yet many cellular activities (such as shape changes during morphogenesis, axonal extension and spindle assembly) involve highly coordinated microtubule behaviour and possibly require force generated by an intermicrotubule sliding mechanism, or perhaps use sliding to move microtubules rapidly into a protrusion for stabilization. Here we show that active sliding between cytoplasmic microtubules can occur in microtubule bundles of the amoeba Reticulomyxa. A force-producing mechanism of this sort could be used by this organism to facilitate the extension of cell processes and to generate the dynamic movements of the cytoplasmic network.     

Multiple ionization of atom clusters by intense soft X-rays from a free-electron laser

Intense radiation from lasers has opened up many new areas of research in physics and chemistry, and has revolutionized optical technology. So far, most work in the field of nonlinear processes has been restricted to infrared, visible and ultraviolet light, although progress in the development of X-ray lasers has been made recently. With the advent of a free-electron laser in the soft-X-ray regime below 100 nm wavelength, a new light source is now available for experiments with intense, short-wavelength radiation that could be used to obtain deeper insights into the structure of matter. Other free-electron sources with even shorter wavelengths are planned for the future. Here we present initial results from a study of the interaction of soft X-ray radiation, generated by a free-electron laser, with Xe atoms and clusters. We find that, whereas Xe atoms become only singly ionized by the absorption of single photons, absorption in clusters is strongly enhanced. On average, each atom in large clusters absorbs up to 400 eV, corresponding to 30 photons. We suggest that the clusters are heated up and electrons are emitted after acquiring sufficient energy. The clusters finally disintegrate completely by Coulomb explosion.     

学科馆员——图书馆员的新追求

从发挥图书馆职能入手，阐述了学科馆员产生的必要性，通过对学科馆员的概念内涵、岗位职责、与传统参考馆员比较及我国高校图书馆学科馆员现状的分析，探讨了如何才能做好学科馆员，为读者提供优质服务。