Research on Angular Output Velocity of a Drive Shaft with Double Cross Universal Joints

The study object is the angular output velocity of the drive shaft which is made up of two series-wound cross universal joints. We have deduced the function relation between the angular output velocity and initiative input angle of the drive shaft with double cross universal joints that is based on the calculation formula of the angular output velocity of a single cross universal joint, and by analyzing the relation between the two input angles. By using this function relation, the constant velocity condition of the drive shaft with double cross universal joints＂ is verified. The step-by-step searching algorithm is adopted to obtain the optimal phase angle that leads to the minimum fluctuate index of the angular output velocity in the vary velocity condition. At the same time, we worked out the maximal and minimum value of the angular output velocity, and their initiative input angle. The correctness of the function of the angular output velocity and the step-by-step search algorithm are verified by an ADAMS simulation example.

Application and Realization of Rapid Searching Technology in the RL & SM Universal Fixture System

A searching-machining system of RL & SM (Rapid Location and State Memory) universal fixture is here introduced, and the concept of rapid searching technology and manufacturing information transformation is then described, with the appropriate control methods and key techniques for its realization being proposed and also practically realized. Theoretical analysis and experimental results show that the proposed idea and methods are feasible to serve as in the practical application of the RL & SM system.

Rhombic Cell Analysis - A New Way of Probing the Large- Scale Structure of the Universe. I.General Considerations

A new way of probing the large-scale structure of the universe is proposed. Space is partitioned into cells the shape of rhombic dodecahedron. The cells are labelled 'filled' or 'empty' according as they contain galaxies or not. The cell size is so chosen as to have nearly equal numbers of filled and empty cells for the given galaxy sample. Two observables on each cell are definable: the number of its like neighbors, n1, and a two-suffixed topological type τ, the suffixes being the numbers of its like and unlike neighbor-groups. The frequency distributions of n1 and T in the observed set of filled (empty) cells are then considered as indicators of the morphology of the set. The method is applied to the CfA catalogue of galaxies as an illustration. Despite its limited size, the data offers evidence 1) that the empty cells are more strongly clustered than the filled cells, and 2) that the filled cells, but not the empty cells, have a tendency to occur in sheets. Further directions of development both in theory and application are indicated.

M.A. AND PH.D. DISSERTATIONS 1994-95 INSTITUTE FOR THE HISTORY OF ANCIENT CIVILIZATIONS NORTHEAST NORMAL UNIVERSITY, CHANGCHUN

Ma Xiaoying, Assyriology, Ph.D., 1994.12 "Women’s Social Status in Old Babylonia Reflected in Marital Property" (Supervisors: Professors Lin Zhichun, Thomas Lee, Tova Meltzer, Wu Yuhong) Wang Liying, Classics, Ph.D., 1995.6 "Sallust’s Bellum Catilinae" (Supervisors: Porfessors Wang Dunshu, P.Ruth Taylor-Briggs, F. Ahlheid, Lin Zhichun)

三叉杆-球笼式万向联轴器组合传动轴系统的动力学仿真研究

为了解三叉杆-球笼式万向联轴器组合传动轴系统的动态特性,为以后的设计工作提供理论依据,对三叉杆-球笼式万向联轴器组合传动轴系统的滑移销、叉杆臂和钢球等关键部件进行了研究。运用ADAMS软件对三叉杆-球笼式万向联轴器组合传动轴系统建立了动力学仿真模型,并对其分别进行了无摩擦和有摩擦条件下的动力学仿真,得到了关键部件的受力曲线图和摩擦力曲线图。研究结果表明,在三叉杆-球笼式万向联轴器组合传动轴系统中,钢球受力曲线的波动和突变最大,说明钢球属于易磨损部件;相比无摩擦时的受力曲线,有摩擦时作用在各个部件上的受力曲线波动变强,更能反映出该三叉杆-球笼式万向联轴器组合传动轴系统的真实受力情况。

5LZ172-Ⅲ型长寿命螺杆钻具的研制

针对5LZ172-Ⅱ型螺杆钻具使用寿命短,难以满足施工要求的问题,通过改进旁通阀结构、研制等壁厚定子及配套转子、采用油密封传动轴以及挠轴等结构,研制出5LZ172-Ⅲ型高性能长寿命螺杆钻具。现场应用情况表明,5LZ172-Ⅲ型螺杆钻具在钻井液大排量条件下使用寿命为316 h,该钻具在多口井的应用中均获得了260 h以上的长寿命,同时减少了钻井过程中不必要的起下钻作业,提高了机械钻速,缩短了建井周期。

三叉杆-球笼式万向联轴器传动轴的运动仿真分析

针对三叉杆-球笼式万向联轴器传动轴结构复杂,难以采用传统的图解法、解析法获得其运动规律的问题,采用Pro/E软件,在充分考虑各构件之间的相互约束关系的基础上,对三叉杆-球笼式万向联轴器传动轴整体进行了三维建模,仿真分析了传动轴中关键零件钢球的运动规律,得到了输入轴和中间轴分别在10°、20°和30°夹角下钢球中心的位移、速度和加速度等运动曲线。仿真结果表明,钢球随输入轴的等速回转做近似周期性的简谐运动,并且两个联轴器夹角越大,各运动参数波动的幅度也越大;该仿真结果为合理设计三叉杆-球笼式万向联轴器传动轴,有效解决其在应用中的摩擦、磨损、润滑问题打下了基础。

Journal of University of Science and Technology Beijing

This journal provides an international medium for the publication of theoretical and experimental studies related to the fields of Mineral, Metallurgy and Materials. Papers dealing with mineral processing, mining, mine safety, environmental pollution and protection of mines, process metallurgy, metallurgical physical chemistry, metals working, structure and physical properties of materials, corrosion and resistance of materials, are viewed as suitable for publication.

Relationship between Beating and Setting-on Place

In this paper,what causes the setting-on place of woven fabrics without adopting tension compensation is explained by means of experimental methods.Owing to that the main shaft speed and the beating speed of reed can not attain the normal values at setting-on,the warp tension and the beating force of the reed can neither reach the normal level.Therefore,the relative slippage movement of the weft against the warp during beating will be less,while the common movement of the weft together with the warp will be bigger than those at nor-mal running.As a result,the setting-on place is

Anisotropic power spectrum and the observed low-l power in PLANCK CMB data

In this work,we study a direction dependent power spectrum in anisotropic Finsler spacetime. We use this direction dependent power spectrum to address the low-l power observed in WMAP and PLANCK data. The angular power spectrum of the temperature fluctuations has a lower amplitude in comparison to the ΛCDM model in the multipole range l = 2-40. Our theoretical model gives a correction to the isotropic angular power spectrum Cl^TT ldue to the breaking of rotational invariance of the primordial power spectrum. We estimate best-fit model parameters along with the six ΛCDM cosmological parameters using the PLANCK likelihood code in Cosmo MC software. We find that this modified angular power spectrum fits the CMB temperature data in the multipole range l = 2-10 to a good extent but fails for the whole multipole range l = 2-40.

Super-Large-Scale Structures in the Sloan Digital Sky Survey

We study the super-large-scale structures in the Sloan Digital Sky Survey by cluster analysis, and examine the geometry and the properties of the member galaxies. Two subsamples are selected from the SDSS, Subsample 1 at the celestial equator and Subsample 2 further north. In Subsample 1 we discover two compact super-large-scale structures： the Sloan Great Wall and the CfA Great Wall. The Sloan Great Wall, located at a median redshift of z= 0.07804, has a total length of about 433 Mpc and a mean galaxy density of about six times that of the whole sample. Most of its member galaxies are of medium size and brightness. The CfA Great Wall, located at a median redshift of z = 0.03058, has a total length of about 251 Mpc and includes large percentages of faint and small galaxies and relatively fewer early-type galaxies.

轧机主传动万向接轴及其关键件有限元分析

通过对轧机主传动系统中的关键件——叉头进行三维建模及力学特性分析,发现危险截面出现在叉头顶部即与十字轴相连接的孔面上。以叉头顶部距叉头底面距离和孔面半径为优化所需的设计变量,以最大等效应力为目标函数进行优化设计,得到叉头最佳设计方案。叉头优化设计后所受最大等效应力相比优化前降低了37%。又因在轧机主传动系统中,万向接轴直接受尖峰扭振影响,最为薄弱,故根据优化后的叉头建立万向接轴的有限元模型并对其固有特性进行分析,得到万向接轴的共振点在100 Hz附近,此时的第一阶扭振在传动系统中的破坏性大,因此,轧机工作环境要避免或减少该频率附近的振动,以免共振时峰值扭矩突然增大,造成接轴及其关键零件破坏。

某车型传动轴2阶抖动优化控制

随着动力系统功率扭矩不断提升,十字万向节传动轴2阶抖动问题更加凸显,研究该问题对提升后驱车型乘坐舒适性意义重大。根据传动轴附加弯矩计算公式得出,万向节夹角越大附加弯矩越大,整车抖动越大。文章以某车型起步大油门加速工况的传动轴2阶抖动为研究对象,实车测试分析振动较大位置为传动轴第二中间支撑和后桥主减壳体,进一步分析得知传动轴夹角α3和α4较大。根据分析结果提出了调整传动轴夹角和等速万向节改制等两种优化方案,并且整车验证优化效果明显。该研究内容对优化传动轴2阶抖动问题具有较强的工程意义。