浅谈交通运输肇事后逃逸的罪责问题

近年来,在处理交通肇事案时,我们常常为如何对交通肇事者的事后逃逸行为的定性产生分岐.虽然有关的司法解释对此已作了规定,但是由于司法实践中情况千变万化,总是不断更新着人们对事物的原有认识,根据具体情况具体分析的原则,我们认为有必要对这～问题作进一步的探讨.     

行星挥发分提取和分析

行星挥发分是指可以通过撞击、加热等物理过程从行星表面固体样品中分离出的气相物质.这些物质一方面对于研究太阳系的形成和行星及其卫星的演化至关重要,另一方面可以为深空探测提供资源.随着近几十年来对深空的探索,挥发分的探测结果也不断刷新人类对宇宙的认识.例如,月球极地冰的发现改变了对月球匮乏挥发分的印象;在火星上检测到疑似生物成因甲烷重燃了火星曾经存在生命的希望;67P彗星氢同位素探测指示地球上的水大部分来自小行星,而不是彗星.在深空探测中,高温热解炉是挥发分提取的主要手段,质谱分析是测试的主要方法.本文总结了深空探测中挥发分的提取方法和功能参数,并对比了挥发分测量质谱仪的性能指标.此外,本文还介绍了未来的深空探测任务用于挥发分探测的载荷.     

行星减速机传动的测量研究

本文主要论述了行星减速机传动力矩的测量方法,通过伺服系统测量行星减速机的传动力矩及力矩波动值,同时结合整个传动机构各部件特性,分析影响减速机传动过程中的因素.     

环双星系统中行星-行星之间的散射

流体模拟的研究表明,如果多颗行星形成在环绕双星的气体盘中,行星之间的会聚迁移会导致行星之间的散射.本文系统研究了环双星的行星系统中两颗等质量行星(P型行星)之间的散射,目的是探讨散射对P型行星系统构型的影响.数值模拟的研究表明散射后只剩一颗行星的几率最大,一般80%.从某种意义上说,伴星的存在有利于行星的存活,尤其是在靠近双星的地方.我们发现散射会导致行星的向外迁移,这和单恒星系统中的散射现象相反,此现象可以用来解释最近通过成像方法发现的远距离P型行星.即便对于等质量的行星,散射位置的不同会造成偏心率分布的多样性.在靠近双星的位置,幸存行星的偏心率较小;在远离双星的位置,剩余行星的偏心率较大.此外,P型行星之间的散射可使P型行星转变为围绕一颗主星运行的S型行星.     

高能不等核碰撞中的参与者数和二元核子核子碰撞数

采用核核碰撞的Glauber模型,给出了高能d核与Au核在不同对心碰撞中的参与者数与二元核子核子碰撞数,所得结果与RHIC PHOBOS合作组给出的结果相吻合.     

行星齿轮轴承早期失效分析

针对某型直升机用行星齿轮轴承出现早期的疲劳失效现象,提出了双列球面滚子轴承要达到最佳运动状态须满足的两个基本条件,分析了影响轴承滚子与内圈滚道接触点位置的主要因素,提出该轴承早期失效的主要原因是产品结构设计的几何参数选取不当,零件制造精度不够精确所致,并在轴承的设计和测量等方面提出了相应的改进措施.     

行星轮式搅拌器的实验与数值模拟

在实验和数值模拟的基础上重点研究一种新型搅拌器——行星轮式搅拌嚣,对搅拌器的搅拌功率、搅拌效率进行实验和分析,并与传统的推进式、锚式搅拌器进行比较.实验表明,其搅拌功率准数小于推进式、锚式等传统搅拌器,搅拌效率优于推进式、锚式搅拌器.搅拌过程中,行星轮发生公转和自转,同时产生较好的径向流和轴向流,形成高湍动的充分混和区...     

An extrasolar planetary system with three Neptune-mass planets

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.     

Transiting extrasolar planetary candidates in the Galactic bulge

More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to reflex motions of their host stars, and more recently through transits of some planets across the faces of the host stars. The detection of planets with the shortest known periods, 1.2-2.5 days, has mainly resulted from transit surveys which have generally targeted stars more massive than 0.75 M(o), where M(o) is the mass of the Sun. Here we report the results from a planetary transit search performed in a rich stellar field towards the Galactic bulge. We discovered 16 candidates with orbital periods between 0.4 and 4.2 days, five of which orbit stars of masses in the range 0.44-0.75 M(o). In two cases, radial-velocity measurements support the planetary nature of the companions. Five candidates have orbital periods below 1.0 day, constituting a new class of ultra-short-period planets, which occur only around stars of less than 0.88 M(o). This indicates that those orbiting very close to more-luminous stars might be evaporatively destroyed or that jovian planets around stars of lower mass might migrate to smaller radii.