露地和温室栽培模式下西兰花中3种农药的残留动态与风险评估

西兰花是中国典型的出口兼内销蔬菜品种。毒死蜱、辛硫磷和茚虫威是中国蔬菜生产中的常用农药。通过田间试验,对比这3种农药在露地和温室栽培模式下,按照推荐剂量和1.5倍推荐剂量用药,在西兰花花球、叶片和土壤中的残留动态。样品采用QuEChERS方法处理和液相色谱-质谱（LC-MS/MS）多残留检测。验证结果表明：在质量比分别为0.02、0.2和1 mg/kg时,毒死蜱、辛硫磷和茚虫威的添加回收率分别为85.8%~101.0%、90.8%~105.3%和86.1%~107.5%。3种农药的最低检出限（LOD）为0.006 mg/kg,最低定量限（LOQ）为0.01 mg/kg,满足方法要求。残留动态结果表明：在西兰花花球上,毒死蜱的半衰期为5.53~7.20 d,辛硫磷为3.55~3.92 d,茚虫威为6.11~7.73 d;在西兰花叶片上,毒死蜱的半衰期为4.33~6.93 d,辛硫磷为3.85~5.77 d,茚虫威为3.85~5.33 d;在土壤中,毒死蜱的半衰期为23.1~34.6 d,辛硫磷为23.1~34.6 d,茚虫威为17.3~23.1 d。最终残留对比表明,3种农药在西兰花叶片的残留量高于花蕾的残留量。在试验剂量施用量条件下,茚虫威和毒死蜱的限量标准不会超过现有欧盟、日本、CAC标准;在高剂量使用条件下,辛硫磷会出现超标现象。     

细胞色素c与氧化石墨烯的吸附研究

通过分子动力学模拟,研究细胞色素c在氧化石墨烯表面的吸附行为.结果表明,细胞色素c和氧化石墨烯之间有较强的结合趋势.均方根涨落及回转半径分析表明,部分体系的吸附构象与原始构象比较接近,但P3系统有着较大的偏离.这些结果表明,在某些构象中,氧化石墨烯可能将细胞色素c结构破坏.     

吸附在Au(100)、Au(110)和Au(111)表面的CTAB双分子层的结构和动力学性质的分子模拟

金纳米棒的各向异性生长常被认为是由于金表面吸附溴化十六烷基三甲基铵（CTAB）双分子层导致的。利用密度泛函理论（DFT）研究溴离子在（100）、（110）和（111）3种金表面上可能的吸附位点,根据它构建金表面CTAB双分子层模型,再利用分子动力学模拟方法研究这种烷基链互相交错排布的双分子层的结构。此外,动力学性质研究表明外层CTAB有着明显的横向扩散现象,而在法向上则出现上下起伏振动。相比较而言,在（111）表面上的双分子层结构的横向扩散和法向涨落更加显著。用外层单个CTA⁺脱离双分子层所需要的能量表征金表面CTAB双分子层的稳定性。结果表明（111）表面的CTAB双分子层的稳定性弱于其他两种金表面上的CTAB双分子层。认为这是因为（111）表面上的CTAB双分子层的排布密度相对较低,导致它相对于其他两种表面的双分子层有更高的扩散性和较低的稳定性。这可能是金纳米颗粒倾向于沿（111）表面生长的原因。     

Examining social identity and intrateam moral behaviours in competitive youth ice hockey using stimulated recall

Social identity – identity formed through membership in groups – may play an important role in regulating intrateam moral behaviour in youth sport (Bruner, M. W., Boardley, I., & Côté, J. (2014). Social identity and prosocial and antisocial behavior in youth sport. Psychology of Sport and Exercise, 15(1), 56–64. doi:10.1016/j.psychsport.2013.09.003). The aim of this study was to qualitatively examine this potential role through stimulated recall interviews with competitive youth-ice-hockey players. Twenty-three players (M_age = 13.27 years, SD = 1.79) who reported engaging in high, median or low frequency of antisocial teammate behaviour (determined through pre-screening with the Prosocial and Antisocial Behaviour in Sport Scale [Kavussanu, M., & Boardley, I. D. (2009). The prosocial and antisocial behavior in sport scale. Journal of Sport and Exercise Psychology, 31(1), 97–117. doi:10.1123/jsep.31.1.97]) were recruited from eight youth-ice-hockey teams in Canada. Interviews involved participants recalling their thoughts during prosocial/antisocial interactions with teammates, prompted by previously recorded video sequences of such incidents. Thematic analysis of interview data revealed all athletes – regardless of reported frequency of intrateam antisocial behaviour – felt prosocial interactions with teammates enhanced social identity. In contrast, the perceived influence of antisocial teammate behaviour on social identity differed depending on athletes’ reported frequency of intrateam antisocial behaviour; those reporting low and median frequencies described how such behaviour undermines social identity, whereas athletes reporting high frequency did not perceive this effect. The study findings highlight the potential importance of intrateam moral behaviour and social identity for youth-sport team functioning.     

Kinetic analysis of the lower limbs in baseball tee batting

The purpose of this study was to investigate effects of the ground reaction forces on the rotation of the body as a whole and on the joint torques of the lower limbs associated with trunk and pelvic rotation in baseball tee batting. A total of 22 male collegiate baseball players participated in this study. Three-dimensional coordinate data were acquired by a motion capture system (250 Hz), and ground reaction forces of both legs were measured with three force platforms (1,000 Hz). Kinetic data were used to calculate the moment about the vertical axis through the body’s centre of mass resulting from ground reaction forces, as well as to calculate the torque and mechanical work in the lower limb joints. The lateral/medial ground reaction force generated by both legs resulted in the large whole body moment about its vertical axis. The joint torques of flexion/extension of both hips, adduction of the stride hip and extension of the stride knee produced significantly larger mechanical work than did the other joint torques. To obtain high bat-head speed, the batter should push both legs in the lateral/medial direction by utilising both hips and stride knee torques so as to increase the whole body rotation.     

非惯性系动力学的第一积分

现行理论力学教材[1-4]在质点的非惯性系动力学中一般只讨论其相对运动微分方程,没有对其进行时,空的全部积分．本文首先积分出动量、动能定理．然后对其第一积分进行了分析讨论,指出了第一积分在应用方面的困难．最后举例说明了动能定理在应用方面是具有其优势的．     

初析中小学生体育学习动力

学生体育学习动力问题直接关系到体育教学的成效,因而成为广大体育教育研究者所关注的热点问题之一。本研究通过社会、学校、家庭和个人四个方面的分析,总结得出中小学生体育学习动力的来源及其阻碍因素,最终提出激发和促进体育学习动力的对策。以期给体育工作者一种新的体育学习动力理论认识,解决体育教师在教学实践中的实际问题,并为当前的课程改革提供必要的理论支持。     

群体动力学视域下成人体育教育管理创新

群体动力学的研究为协作学习的倡导者提供了重要启示,应正确认识成人体育教育群体和谐互动的整体性,抛弃以自我中心论,并结合各成人体育院校的实际情况,制定管理最优化措施,以促进成人体育教学各项工作稳定、可持续的发展.     

基于VB的材料力学仿真实验系统

本文提出了如何在Windows XP环境下,借助Visual Basic6.0可视化高级程序设计语言,利用大型有限元分析软件ANSYS10.0开发材料力学仿真实验软件的设计思路,并给出了相应的具体开发方案,为今后材料力学仿真实验软件的开发探索出一种新方法,对材料力学仿真实验教学进行了有益尝试.     

重大项目“大型旋转机械非线性动力学问题” 取得重要进展

国家自然科学基金重大项目“大型旋转机械非线性动力学问题”（编 号19990510）经过各参加单位的共同努力，顺利完成了研究计划，通过了国家自然科学基金 委员会数理科学 部和工程与材料科学部组织的结题验收。该项目获得国家自然科学奖二等奖1项、省部级 自然科学奖一等奖1项、科技进步奖一等奖1项及科技进步奖二等奖2项。该项目所取得的研 究成果使我国在非线性动力学、转子动力学、机械故障诊治等研究领域处于国际前沿水平， 部分成果在国际上产生了影响，为推动我国电力工业的科技进步发挥了重要作用。