质点

Further topics include kinematics, particle dynamics, motion relative to accelerated reference frames, work and energy, impulse and momentum, systems of particles and rigid body dynamics.

更进一步探讨运动学，质点动力学，于加速坐标系上之运动行为、功、能量、冲量、动量和质点系统与刚体动力学。

That when a particle meets its antiparticle, the pair always annihilate one another in a burst of energy.

这一理论认为当一个质点和它的反质点相遇时它们就会融合成一股能量。

The length of central region of the cell decreases with the increasing oscillation amplitude and Strouhal number. The movement of Brownian particles can be either periodic or chaotic from whichever region the particles originate.

模拟结果表明，涡胞中心区质点的运动有强周期性，轨迹呈螺旋形状，而边缘区质点的运动是一种混沌行为，两区的质点被分界线隔开；中心区宽度随振幅、Strouhal数的增大而减小；布朗粒子的分子扩散效应可以克服两区分界线的限制。

Result The background noise of bidirectional electrophoresis map of protein extracted by TCAJA method was greater, its clarity was poor, its horizontal striations were more and there were tinny spots with irregular shape appeared on it. The variegated spots had difference from the normal protein spots, they formed high coverage and shading on the other protein spots and affected the accurate expression of map information. The background noise of bidirectional electrophoresis map of protein extracted by Trizol method was little, its horizontal striations and non-protein impurities were less, there was no shading phenomenon strong spots and mere protein spots, so it provided abundant information for quantitative and qualitative analyses on the proteome from buffalo grass seeds, Compared with TCA/A precipitation.

结果］TCA/A法提取的蛋白质双向电泳图谱背景噪音大，清晰度差，横向条纹较多，图谱上呈现多个形状不规则的斑点，杂色与正常蛋白质点有区别，对其他蛋白质点构成高度及盖和遮进，影响图谱信息的准确表达；Trizol法所提取的蛋白质样品，其双向电泳图谱背景嗓音小，横向条纹少，非蛋白类杂质少，无斑点间的这进现象，蛋白质点数量增多，为野牛草种于蛋白质组定量、定性分析提供了丰富的信息。

It is proved that arc coordinates of a directed curve cannot be used as ordinary coordinates or generalized coordinate s for the motion of an Appell-Hamel particle without a fixed orbit, but they can be used as quasi coordinates.

证明了弧长坐标 s在轨道未知的 Appell- Ham el质点运动中不能作为普通坐标或广义坐标，但可以作为准坐标，指出文献 [1]中引入弧长 s坐标的做法及"Appell- Ham el质点运动的轨迹是一般螺线"的结论是正确的，但其Appell- Ham el约束是完整约束及在该质点运动中 s坐标是广义坐标的观点是错误的。

Key words: analytical mechanics; event space; variable mass; nonholonomic constraint; principle of Jourdain; Noether′s theorem

考虑N个质点组成的系统，其中每个质点的质量mi(i=1，…，N)是时间、位置、速度的函数， i为第i个质点mi的位矢。

The differential equations of three mass points are derived for different mass relations between them,and their analytic solutions are obtained,by which the movement rule of three mass points are discussed.

分析了一个由三质点和弹簧构成的系统的运动问题，给出了三质点质量满足不同关系时各质点的运动微分方程，求出了运动微分方程的解析解，并由此讨论了各质点的运动规律。

The results showed that about610 protein spots could be visualized on the two dimensional electrophoresis map bycoomassie brilliant blue staining within Mr 9.0～100.0kD and pH 4～7,and about 94 spotswere differential expressed between male-sterile line and its maintainer line by PDQuestsoftware.Among those differential proteins,about 49 spots and 40 spots were differentialexpressed between uninucleate anther stage and binucleate stage respectively;Meanwhilecomparing with the 2-DE maps of the total proteins from the binucleate anther stage anduninucleate stage,15 differential spots were detectable at male-sterile line;and 16 differentialspots were detectable at its maintainer line.

在分子量9.0～100.0 kD、等电点4～7线性范围内，可识别约610个蛋白质点，PDQuest软件分析结果表明：在单核期不育系和保持系之间存在40个差异蛋白质点，二核期两者共有49个差异点；不育系在单核期和二核期两者之间存在有15个差异点，保持系在两个不同时期有16个差异点；不育系与保持系间在表达量上的差异蛋白质点以及不育系与保持系间特异表达或特异缺失的蛋白质点很可能与小麦雄性不育有关。3。

Investigating the strengthening and embrittling mechanisms of the second phase particles on BMGs. The average size of the second phase particles significantly affects the fracture strength of BMGs.

全面系统地阐述了第二相质点的强化和脆化问题，第二相质点的强化和脆化问题的关键在于第二相质点的尺寸。

In this project, the selection criteria of matrix and reinforcement for obtaining composites with high strength and toughness are determined. The as-cast and aged microstructures of composites reinforced with particles of different strength are observed, and their metallurgical conditions and stabilization mechanisms are analyzed. The aging precipitation behaviors and mechanisms are studied. Some characteristics of nano-materials (micro-distortion areas) are found in 150nm- Al2O3p/Al composites and their formation mechanisms are expatiated. The "flexible" restriction to the deformation of the matrix by low strength AlN particle is observed by in-situ TEM and SEM techniques, and the mechanisms of its resist on cracks propagation and its contribution to composite strength are revealed. The high temperature deformation behaviors of Al2O3p/Al composites are studied. A rare-earth coating is established on sub-micron Al2O3 particles, leading to an improvement in wettability between coated Al2O3 and liquid aluminum and a decrease in infiltration pressure. The strength and ductility of coated particles reinforced composite are also increased. The interfacial characteristics, bonding structures and their formation mechanisms are studied, and the crystal orientation relationships between reinforcement particles and aluminum matrix are investigated. Finally a lighter composite with better balance of strength and damping properties is reinforced with hollow ceramic microballoons of ultra-lower strength.

本项目发现了获得高强度和高韧性复合材料的基体、增强体选择依据；观察了各种强度质点增强复合材料的铸态和时效态微观组织，分析其微观结构形成的金属学条件及稳定性机理，研究了其时效析出规律和时效机制，发现了150nmAl2O3颗粒增强铝基复合材料基体中的纳米材料特征，并解释了其形成机理；利用TEM和SEM动态拉伸技术发现了低强度质点AlN颗粒对变形协调的&柔性强化&机制，揭示了其对裂纹扩展的阻碍作用和对复合材料高强度的贡献；研究了中强度质点的Al2O3颗粒增强铝基复合材料的高温变形行为，并对其进行了稀土界面层设计与制备，改善了颗粒与铝合金之间的界面润湿性，降低了复合材料铸造渗透压力，提高了复合材料的强、韧性；研究了多种复合材料界面结构及形成机理，确定了增强体与基体之间的界面结合机制，分析了复合材料界面处的晶体学位向关系；最后制备了含微孔的中空型陶瓷颗粒增强的特种复合材料，得到了强度和阻尼综合性能较好的轻质复合材料。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。