背越式弧线助跑起跳腾空产生旋转角动量的力学分析

背越式跳高至起跳开始,身体重心沿着起跳角形成的固定抛物轨迹运行,身体围绕自身的轨迹旋转达到尽可能的高度,在旋转过程中,经纵轴的背对横杆和水平轴的面部朝上,身体绕两个轴线动作的扭转过杆,结合助跑的水平速度与两个轴线的本身动作,在某种程度上我们要应有个清楚的概念,身体扭旋过杆是由角动量产生的和角动量的形成又如何影响着身体的扭旋。     

激光短脉冲的高导数引力场

引入Teyssandier规律条件,求得线性高导数引力场方程的一般非静态解,利用高导数引入理论研究沿光波导传输的激光短脉冲产生的引力场,并与广义相对论的结果进行比较。     

Gravity anomaly during the Mohe total solar eclipse

By using a high-precision LaCoste-Romberg (D-122#) gravimeter, continuous and precise measurements were carried out during the March 9, 1997 total solar eclipse in the Mohe region in Northeast China. The gravity variations were digitally recorded during the total solar eclipse so as to investigate the possible anomaly of the sun and the moon’s gravitational fields on the earth. After the careful processing and analysis of the observed data, no significant anomaly during the very solar eclipse has been found. However, there are two ‘gravity anomaly valleys’ with near symmetrical decrease of about 6–7 μGal at the first contact and the last contact. This is the anomaly phenomenon observed and reported for the first time in the literature. This note presents some analyses and discussions.     

Effects of gravity waves on the distributions of O3 and OH in the mesopause region

A dynamical-photochemical model of atmospheric gravity waves is used to study the influences of gravity waves on distributions of atmospheric minor species through transportation and photochemical reactions. We mainly study the effect of gravity waves on the distributions of atmospheric trace gases through the nonlinear photochemical reactions. O₃ and OH are taken as examples in this note. The calculations indicate that the effect of gravity waves on the distributions of atmospheric trace gases is mainly through the nonlinear photochemical reactions in the mesopause region. The contribution of the nonlinear photochemical reaction caused by gravity waves can exceed the nonlinear transportation and the eddy diffusion.     

齿型基岩面法改善重力坝坝基抗滑稳定性

为改善重力坝的抗滑稳定性,提出一种齿型基岩面设计与施工方法.分析认为,若选择三角齿方案,在起伏角为40°左右且齿高不低于混凝土最大骨料粒径时,基岩面的抗剪能力可望达到混凝土本体的水平,坝基抗滑稳定安全系数有很大提高.     

某电站勘探平洞超挖块体评价

通过某电站勘探平洞的超挖测绘,分析了平洞超挖块体的边界条件,确定了超挖块体的类型及其特征,推导了各类型超挖块体体积及其有关重心位置的计算公式,评价了各类型超挖块体的体积及其相关分布模型,以及块体重心位置的分布特征,这对于节理岩体地下洞室稳定性评价以及加固处理方案的确定具有一定指导意义。     

水平井蒸汽辅助重力泄油凝结水膜对泄油率的影响

前人建立的水平井蒸汽辅助重力泄油采油工艺理论求解方法是将凝结水和被加热原油作为一个均匀混合体 ,并按原油来处理 ,即忽略了凝结水膜的影响。笔者在此基础上进一步考虑了凝结水膜的客观存在和实际影响 ,导出了新的泄油率计算公式 ,并首次推导出水膜层厚度及泄水率的计算公式 ,证实原有理论对泄油率作了过高估计。运用新的计算公式可准确地预测泄油率 ,还可用于预测泄水率     

基于方位传感的地下管线探测系统的研制

介绍一种适于非开挖地下管道的三维形状探测系统,该系统主要由以重力加速度计、磁强计、定心机构组成的传感头、计程机构、控制电路及上位机控制系统组成.传感头在管道内拖动过程中,在每个采样点处通过传感器采集该采样点处的方向角信息,然后结合计程机构所获得的采样点间的间距,可以得到管道相应位置的三维坐标及管道轴线的空间形状.该管道探测系统在管道位置深度的重复测量精度可达到±5%.     

三塘湖盆地原油物性特征及其影响因素

在对三塘湖盆地不同层位原油物性分布特征研究的基础上,结合地质条件,分析了影响原油物性特征的各种因素。原油物性不仅受原油族组成的影响,而且也受成熟度、埋藏深度、保存条件、组分重力分异作用等的影响。相对密度的影响因素较多,主要包括饱和烃、芳香烃、胶质含量、沥青质和含蜡量等,粘度主要受饱和烃、芳香烃、胶质含量的影响,沥青质和含蜡量对其影响不大。牛圈湖油田芦草沟组原油物性变化不同于其它地区和其它层位,其随深度增加而升高,主要是油气藏中烃类重力分异作用的结果。其它地区原油物性随深度增加而降低的特征主要与保存条件、水洗作用、氧化作用等因素有关。该认识对于其它地区原油物性分布特征的研究具有重要的参考价值。     

Suppressing spacetime emergence

One of the primary tasks in building a quantum theory of gravity is discovering how to save spatiotemporal phenomena using a theory which, putatively, does not include spacetime. Some have taken this task a step further and argue for the actual emergence of spacetime from a non-spatiotemporal ontology in the low-energy regime. In this paper, it is argued that the account of spacetime emergence presented in Huggett and Wüthrich (2013) and then assumed in Baron (2019), Crowther (2016), Wüthrich (2017), and Wüthrich and Lam (2018) fails to accomplish the task to which it is set. There is a prima facie contradiction between the scale-independent ontology of spacetime in GR and the scale-dependent account of emergence proposed by this literature. One can avoid this contradiction but only at the cost of changing the target of emergence and by endorsing a perspectival theory of ontology – a view I call “ontic-perspectivism”. Though this paper explicitly addresses spacetime emergence, many of the following arguments are applicable to other accounts where objects of ontology, or their properties, are claimed to emerge in the low-energy regime.