Growth control of normal and transformed cells.

Both serum factors and protein synthesis are required for normal cell growth. Swiss 3T3 cells require the serum growth factors insulin and EGF (epidermal growth factor) during the initial part of the G1 period, until they pass a restriction point about 2 h before the initiation of DNA synthesis. Concentrations of cycloheximide that inhibit protein synthesis by as much as 70% dramatically lengthen the cell cycle before the restriction point, while the cell cycle after the restriction point remains nearly constant. These results are consistent with a model in which labile proteins are required for transit of cells past the serum-sensitive restriction point. The relation of these findings to the growth control of transformed cells is discussed.     

数控机床空间误差的无模测量与补偿

提出了用激光杆仪直接测量数控机床刀具的定位误差，实现空间误差无模识别的方法，建立了误差预报的三维网格模型，利用有限元方法实现空间任意一点误差的预报，在XK713数控加工中心上进行了本方法的误差测量，预报和补偿实验，结果表明所提出的误差测量方法具有操作方便、成本底、精度高的特点，误差的预报和补偿效果显著。     

Observing the 3D Chemical Bond and its Energy Distribution in a Projected Space

Our curiosity-driven desire to “see” chemical bonds dates back at least one-hundred years, perhaps to antiquity. Sweeping improvements in the accuracy of measured and predicted electron charge densities, alongside our largely bondcentric understanding of molecules and materials, heighten this desire with means and significance. Here we present a method for analyzing chemical bonds and their energy distributions in a two-dimensional projected space called the condensed charge density. Bond “silhouettes” in the condensed charge density can be reverse-projected to reveal precise three-dimensional bonding regions we call bond bundles. We show that delocalized metallic bonds and organic covalent bonds alike can be objectively analyzed, the formation of bonds observed, and that the crystallographic structure of simple metals can be rationalized in terms of bond bundle structure. Our method also reproduces the expected results of organic chemistry, enabling the recontextualization of existing bond models from a charge density perspective.     

Mellifluous matures to malodorous in musth

Male Asian elephants in musth--an annual period of heightened sexual activity and intensified aggression--broadcast odoriferous, behaviourally influential messages from secretions of the temporal gland. From our observations in the wild, together with instantaneous chemical sampling and captive-elephant playback experiments, we have discovered that young, socially immature males in musth signal their naivety by releasing honey-like odours to avoid conflict with adult males, whereas older musth males broadcast malodorous combinations to deter young males, facilitating the smooth functioning of male society. As elephant--human conflicts can upset this equilibrium, chemically modulating male behaviour may be one way to help the conservation of wild elephants.     

Petri网可视化工具的设计与实现

应用面向对象思想和可视化编程工具VisualC 语言开发了图形化的Petri网建模工具GPNT，GPNT系统作为一个计算机辅助设计和分析工具，使用户可在交互式的计算机图形方式下进行Petri网的建立，删除，修改和存储，并可通过对关联矩阵的初等线性变换求解Petri网的S不变量和T不变量，本GPNT系统可用于Petri网模型的设计，分析和动态仿真。     

散乱数据云的自适应网格划分

提出了一种基于图像边缘检测的自适应网格划分算法，用此方法可以根据测量曲面的几何特征控制型值点的疏密分布，并在保证模型精度的同时，减少了模型数据量，该算法分图形-图像灰度映射，细化点检测，网格自适应细化三个部分，图形-图像灰度映射将三维数据云映射为灰度图像，通过图像处理检测细化点，定位细化点的位置，由此实现网格自适应细化，在柴油机引擎的测量数据云上的应用表明，该方法可以显著地降低模型数据量，提高建模效率。     

大型复杂曲面零件加工余量均布优化问题研究

提出通过曲面的初始匹配和精确匹配来实现余量分布的优化，初始匹配决定后续算法的变量空间；精确匹配获得最佳的曲面匹配姿态及最佳的余量分布，精确匹配采用最小二乘方法构造评估函数，应用遗传算法和单纯形法混合寻优，直接对问题涉及的曲面匹配变换矩阵的6个未知量求解，应用结果表明该方法具有易地实现，算法稳定等特点，较好解决了大型复杂曲面类零件加工余量计算问题。     

螺旋锥齿轮数控展成轨迹生成及直接插补算法

给出了螺旋锥齿轮五坐标NC展成加工运动和直接插补算法，该直接插补算法以NC原理上的最小步长逼近展成轨迹，可获最大展成运动精度，在综合考虑展成允许误差，机床动力特性及伺服驱动能力的基础上，给出了进给速度的限制修正及平滑处理算法，该算法可作为螺旋锥齿轮数控机床数控系统核心处理算法。