Allelopathic potential ofnuphar lutea (L.) Sibth. & Sm. (Nymphaeaceae)

Aqueous extracts ofNuphar lutea (L.) Sibth. & Sm. leaves (blades plus petioles) and roots plus rhizomes were tested for allelopathic activity using lettuce seedling andLemna minor L. assay systems. The 12.5, 25, 125, and 250 parts per thousand (ppt) treatments of both extracts killed the lettuce seedlings. At 2.5 ppt of extract, radicle growth of lettuce was 29% of the control for leaves and 31% of the control for roots plus rhizomes.Lemna minor frond number was reduced to 34% of the control by the 25 ppt leaf extract and to 43% of the control by the 25 ppt roots plus rhizomes extract.L. minor was killed by concentrations of 125 ppt and above of both plant part extracts. As expected, the frond number and total chlorophyll content measured by theL. minor assay were highly correlated. Osmotic potentials below 143 mOsmol/kg had no influence onL. minor growth. Neither the osmotic potential nor the pH of the undiluted extracts ofN. lutea were in the range known to influence the growth of either lettuce seedlings orL. minor. Nuphar lutea extracts were many times more inhibitory than 16 other hydrophytes we previously examined.     

运用遥感及非地震物探数据划分盆地三级构造单元

中国尚有数百个盆地处于早期油气勘探阶段，盆地早期评价方法研究意义重大。遥感及非地震物探数据各有特长，在盆地早期评价中可发挥重要作用。提出基于遥感及非地震物探数据的盆地三级构造单元平面与剖面立体综合解释模式。以百色盆地为试验区，阐述了该模式的具体工作步骤和应用效果。该模式的核心是两种数据的综合分析与立体结合，其关键是利用两种不同层次数据的综合分析来确定断层的性质。该方法应用效果明显     

基于势场的运动路径规划

本文阐述了基于势场的三轮自治车(AV)运动路径规划,以由障碍物和目标产生的虚拟势场力作为 AV运动的驱动力.先讨论了势场力的存在条件包括距离条件和方向条件并提出了计算方法,然后讨论了把 AV 简化成杆的运动路径规划,包括 AV 及杆的运动机理、加权势场合力的求法及其控制作用和运动定位等问题.最后给出了仿真结果.本文首次将势场法应用于三轮 AV 的路径规划.     

云南晚第三纪地层分区及其含油气性

云南上第三系为山间盆地沉积。依据盆地的大地构造位置、地理位置、地层发育情况、基岩性质、沉积物及古生物特征，可划分为滇东、滇西２个地层区和１１个地层分区：昭通—会泽、宣威—曲靖、文山—广南、玉溪—建水、楚雄—元谋、丽江—洱源、兰坪—永平、思茅—江城、临沧—澜沧、保山—镇康、腾冲—潞西。分析各区的地层层序、区域地质特征及含油气性，认为滇东区的曲靖—宣威、丽江—洱源，滇西区的思茅—江城、保山—镇康等地层分区的一些盆地，烃源岩厚度、有机质丰度等指标和生储盖组合条件相对较好，有可能形成油气聚集带，为较有利的油气勘探领域。图１参６（梁大新摘）     

O_2/Si(100)-2×1重构表面相互作用过程的动力学研究

对双原子分子O2与Si（100）－2×1重构表面的相互作用过程进行了动力学研究。建立了相互作用系统的LEPS势能超曲面，并在此基础上采用准经典轨迹方法计算了不同特征吸附位上的分子运动轨迹，得到了与理想表面模型相比更为合理的表面吸附特性。     

Consideration of some dilute-solution phenomena based on an expression for the Gibbs free energy

Rigorous expressions based on the Lennard-Jones (6–12) potential, are presented for the Gibbs and Helmholtz free energy of a dilute mixture. These expressions give the free energy of the mixture in terms of the thermodynamic properties of the pure solvent, thereby providing a convenient means of correlating dilute mixture behavior with that of the pure solvent. Expressions for the following dilute binary solution properties are derived: Henry's constant, limiting activity coefficients with their derivatives, solid solubilities in supercritical gases, and mixed second virial coefficients. The Henry's constant expression suggests a linear temperature dependence; application to solubility data for various gases in methane and water shows a good agreement between theory and experiment. In the thermodynamic modeling of supercritical fluid extraction, we have demonstrated how to predict new solubility-pressure isotherms from a given isotherm, with encouraging results. The mixed second virial coefficient expression has also been applied to experimental data; the agreement with theory is good.Paper presented at the Ninth Symposium on Thermophysical Properties, June 24–27, 1985, Boulder, Colorado, U.S.A.     

油气成藏过程研究的地质意义

油气成藏过程研究是含油气盆地研究的重要内容,具有十分重要的地质意义。根据近几年笔者对油气成藏过程研究的实例,认为油气地球化学特征除了具有“源控”特征外,还具有不可忽视的受油气成藏过程控制的特征;对一个地区烃源岩的评价,尤其对高过成熟的烃源岩的生气潜力的评价,不能只停留在静态条件下的评价,必须结合成藏过程综合评价。同时以中西部前陆盆地为例,讨论了油气成藏过程研究对油气勘探方向的指导作用。     

Optimum shapes of tire‐treads for avoiding lateral slippage between tires and roads

Optimum design of tire‐tread sections is an important practical issue. However, useful study of the problem that can suggest a reliable guideline for determining the optimum tread sections had hardly been made in the past. The present paper describes a new analysis of the state of stresses in tire‐tread sections in contact with the road surface, taking special care of the boundary conditions. Based on the analysis, a method is proposed to determine the optimum tread shapes for avoiding lateral slippage between tires and roads. The displacement potential function formulation, an ideal mathematical model for the practical stress problems, has been used in conjunction with finite‐difference method of solution. For the present analysis, lateral slipping in absence of frictional resistance as well as the no‐slip conditions of the tire‐tread contact surface have been considered along with a large number of tread aspect ratios. The present computational approach proves to be a powerful tool for determining the optimum tread shapes for avoiding the lateral slippage of tire‐treads. Copyright © 2005 John Wiley & Sons, Ltd.     

具有粘弹性支撑的平板上势流的稳定性

本文研究了具有粘弹性支撑的平板上均匀势流中的稳定性问题。在研究中采用基于空间－时间稳定性理论的映射法搜寻绝对不稳定特征模态。研究结果表明，当支撑刚度足够小时总量会有不稳定发生。对于纯弹性支撑，尽管有不稳定，但它并不是绝对不稳定；而对于粘弹性支撑，所发生的不稳定则一定是绝对不稳定。