锦屏电站大坝右岸洞室开挖过程控制及对策

锦屏一级水电站大坝右岸地下洞室具有地质条件复杂、施工条件差、干扰因素多、难度大、工程量大、质量要求高、工期紧等诸多特点,因此施工过程控制极其重要。     

A three-dimensional examination of the planar nature of the golf swing

Previous planar models of the downswing in golf have suggested that upper limb segments (left shoulder girdle and left arm) move in a consistent fixed plane and that the clubhead also moves only in this plane. This study sought to examine these assumptions. Three-dimensional kinematic analysis of seven right-handed golfers of various abilities (handicap 0?–?15) was used to define a plane (named the left-arm plane) containing the 7th cervical vertebra, left shoulder and left wrist. We found that the angles of this plane to the reference horizontal z axis and target line axis (parallel to the reference x axis) were not consistent. The angle to the horizontal z axis varied from a mean of 133° (s = 1°) at the start of the downswing to 102° (s = 4°) at impact, suggesting a “steepening” of the left-arm plane. The angle of the plane to the target line changed from ??9° (s = 16°) to 5° (s = 15°) during the same period, showing anticlockwise (from above) rotation, although there was large inter-individual variation. The distance of the clubhead from the left-arm plane was 0.019?m (s = 0.280?m) at the start at the downswing and 0.291?m (s = 0.077?m) at impact, showing that the clubhead did not lie in the same plane as the body segments. We conclude that the left arm and shoulder girdle do not move in a consistent plane throughout the downswing, and that the clubhead does not move in this plane. Previous models of the downswing in golf may therefore be incorrect, and more complex (but realistic) simulations should be performed.     

The Prosocial and Antisocial Behaviour in Sport Scale: Further evidence for construct validity and reliability

Abstract

The purpose of this research was to provide further evidence for the construct validity (i.e., convergent, concurrent, and discriminant validity) of the Prosocial and Antisocial Behaviour in Sport Scale (PABSS), an instrument that has four subscales measuring prosocial and antisocial behaviour toward teammates and opponents. We also investigated test-retest reliability and stability of the PABSS. We conducted three studies using athletes from a variety of team sports. In Study 1, participants (N = 129) completed the PABSS and measures of physical and verbal aggression, hostility, anger, moral identity, and empathy; a sub-sample (n = 111) also completed the PABSS one week later. In Study 2, in addition to the PABSS, participants (N = 89) completed measures of competitive aggressiveness and anger, moral attitudes, moral disengagement, goal orientation, and anxiety. In Study 3, participants (N = 307) completed the PABSS and a measure of social goals. Across the three studies, the four subscales evidenced the hypothesised relationships with a number of variables. Correlations were large between the two antisocial behaviours and small between the two prosocial behaviours. Overall, the findings supported the convergent, concurrent, and discriminant validity of the scale, provided evidence for its test-retest reliability and stability, and suggest that the instrument is a valid and reliable measure of prosocial and antisocial behaviour in sport.     

互成角度的两平面镜成像问题的讨论

夹角为θ的平面镜M和N之间放置一物点P,由反射所成的虚像设为K个,这些像均分布在同一个圆周上,像的总数K=[(180°-α)/θ]+[(180°-β)/θ]。当180°/θ为整数时,K个虚像中有两个像重合,故只有K-1个虚像能被看到;当180°/θ不为整数时,K的值既取决于平面镜M和N之间的夹角,还与物点P所放位置有关。     

对速度瞬心的动量矩定理及其应用

本文从动能定理出发论证了对速度瞬心的动量矩定理,并通过实例阐述了用它求解有瞬心的力学问题更简洁有效。     

Stewart formula and some inequalities for a simplex

1 Stewart formula and inequalities for a simplex Given a triangle ABC, suppose that , ,a bw w and cw are respectively the lengths of the angle bisectors of ?ABC, a, b and c are the lengths of the sides of ?ABC. The well-known Stewart’s formula for a triangle is proved as follows 222222222,( ),( ).( )abca bcw bc b cab cw ac a cabcw ab a b? = ?? +??? = ?? +??? = ? +?? (1) Let 1 2 1n nA A A? += be an n-dimensional simplex in the n-dimensional Euclidean space nE , V be the volume of ;n? kF…     

球面和圆柱面相等对应关系的研究

建立轴射圆柱面投影方法，研究轴射圆柱面投影下球面向圆柱面投影的理论，解决正投影无法解决的复杂的旋转体投影问题．用轴射圆柱面投影法的投影理论，建立球面和圆柱面的一一对应关系，找出二者之间的某些几何规律，该投影下任意形状的球面投影到圆柱面上是相等的，建立球面的轴射圆柱面投影定理，解决球面不规则计算问题．     

关于Gauss－Seidel迭代法的一个收敛定理

本文给出了Ｇａｕｓｓ－Ｓｅｉｄｅｌ迭代收敛的两个充分条件，所给定理比目前常用的判据，应用范围广，且易于检验。     

有关透镜组合基点基面公式的讨论

本文以两个共轴透镜组成的光学系统为例,结合具体的光路图,推导出主点和节点的计算公式,其过程简单,物理意义清晰。     

A Multilevel CFA–MTMM Approach for Multisource Feedback Instruments: Presentation and Application of a New Statistical Model

Multisource feedback instruments are a widely used tool in human resource management. However, comprehensive validation studies remain scarce and there is a lack of statistical models that account appropriately for the complex data structure. Because both peers and subordinates are nested within the target but stem from different populations, the assumption of traditional multilevel structural equation models that the sample on a lower level stems from the same population is violated. We present a multilevel confirmatory factor analysis multitrait–multimethod (ML–CFA–MTMM) model that considers this peculiarity of multisource feedback instruments. The model is applied to 2 scales of the Benchmarks® instrument and it is demonstrated how measures of reliability and of convergent and discriminant validity can be obtained using multilevel structural equation modeling software. We discuss the results as well as some implications and guidelines for the use of the model.