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为揭示微重力环境下加热表面尺寸对气泡动力学行为的影响，通过对比实验研究了不同热流密度条件下两种尺寸芯片表面核态沸腾过程中气泡的动力学行为.结果表明，低热流密度时两种尺寸芯片表面均能维持典型的孤立气泡沸腾，气泡生长合并过程缓慢，仅大芯片表面气泡脱落，并且体积达到小芯片气泡的3.4倍.两芯片在中等热流密度下均呈稳定的核态沸腾，气泡生长合并加速、脱离频率升高.大芯片表面气泡脱离次数明显高于小芯片，脱离气...
X级质子耀斑的特征研究
质子耀斑 非质子耀斑 日冕物质抛射
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2018/5/4
为了更加准确地判断X级耀斑是否引发质子事件，对X级质子耀斑和非质子耀斑的耀斑积分通量、源区、CME速度、CME角宽度、背景太阳风速度及背景X射线通量的分布进行了统计研究.发现非质子耀斑和质子耀斑的积分通量、经度、CME速度和CME角宽度具有明显不同的分布.非质子耀斑大多集中在东部，耀斑积分通量小于0.3J·m-2，CME速度小于1300km·s-1的区域内；质子耀斑大多集中在中部或西部，耀斑积分通...
徽州传统民居内部日照环境研究
徽州传统民居 日照时数 天井高宽比 太阳辐射得热
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2018/11/20
以徽州传统民居作为研究对象，利用Ecotect 软件对其内部的日照时数和光斑分布以及改变建筑朝向及天井高宽比后厢房内的太阳辐射得热量进行模拟。结果表明：民居内部夏季凉爽的主要原因是超过80%的区域的日照时数都小于1h，同时夏季太阳主要照射在天井底部，增强了天井底部水体的自然蒸发冷却和夜晚的自然通风；冬季约15%的高日照时数区域都位于厢房和厅堂的内部，在为居住者提供健康、卫生的室内环境的同时减少了厢...
Interactive evolution of multiple water-ice reservoirs on Mars: Insights from hydrogen isotope compositions
Mars water ice isotope atmospheric escape
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2017/4/10
Remote sensing data from orbiter missions have proposed that ground ice may currently exist on Mars, although the
volume is still uncertain. Recent analyses of Martian meteorites have suggested that ...
Preface: Evolution of the early solar system: Presolar cosmochemical fingerprints and the formation of watery rocky planets
Presolar cosmochemical fingerprints the formation of watery rocky planets
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2017/4/10
Recent developments in cosmochemistry of high-precision
and high spatial resolution isotope analyses, and of
high-performance computing techniques, have enabled
cosmochemists to gain vital insight ...
COUPLED SPIN AND SHAPE EVOLUTION OF SMALL RUBBLE-PILE ASTEROIDS:SELF-LIMITATION OF THE YORP EFFECT
methods numerical–minor planets,asteroids general
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2015/12/25
We present the first self-consistent simulations of the coupled spin-shape evolution of small gravitational aggregates under the influence of the YORP effect. Because of YORP's sensitivity to surface ...
Numerical simulations of collisional disruption of rotating gravitational aggregates:Dependence on material properties
Asteroids Planetesimals Dynamics N-body simulations Collisional physics
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2015/12/25
Our knowledge of the strengths of small bodies in the Solar System is limited by our poor understanding of their internal structures, and this, in turn, clouds our understanding of the formation and e...
Selective sampling during catastrophic disruption:Mapping the location of reaccumulated fragments in the original parent body
Asteroids Collisions Internal structure Gravitational reaccumulations
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2015/12/25
In this paper, we simulate numerically the catastrophic disruption of a large asteroid as a result of a collision with a smaller projectile and the subsequent reaccumulation of fragments as a result o...
Effects of orbital ellipticity on collisional disruptions of rubble-pile asteroids
Celestial mechanics Methods:numerical Minor planets,asteroids:general Planets and satellites:physical evolution
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2015/12/25
The behavior of debris ejected from asteroids after collisional disruptions has significant implications for asteroid evolution. Analytical approximations of the elliptic restricted three-body system ...
Low-speed impact simulations into regolith in support of asteroid sampling mechanism design I:Comparison with 1-g experiments
Asteroids Surfaces Collisional physics Granular material Sampling mechanism Geological processes Regoliths
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2015/12/25
This study is carried out in the framework of sample-return missions to asteroids that use a low-speed projectile as the primary component of its sampling mechanism (e.g., JAXA’s Hayabusa and Hayabusa...
Numerical predictions of surface effects during the 2029 close approach of Asteroid 99942 Apophis
Asteroids,dynamics Asteroids, surfaces Near-Earth objects Regoliths Tides,solid body
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2015/12/25
Asteroid (99942) Apophis’ close approach in 2029 will be one of the most significant small-body encounter events in the near future and offers a good opportunity for in situ exploration to determine t...
The Brazil nut effect and its application to asteroids
methods:numerical comets:general minor planets,asteroids:general
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2015/12/25
Out of the handful of asteroids that have been imaged, some have distributions of blocks that are not easily explained. In this paper, we investigate the possibility that seismic shaking leads to the ...
Numerically simulating impact disruptions of cohesive glass bead agglomerates using the soft-sphere discrete element method
Asteroids, Surfaces Collisional physics Geological processes Regoliths
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2015/12/25
We present our implementation of cohesion in the parallel N-body code pkdgrav in order to model small bodies that are not fully monolithic but that have at least some degree of cohesion. Small bodies ...
ROTATION-DEPENDENT CATASTROPHIC DISRUPTION OF GRAVITATIONAL AGGREGATES
minor planets asteroids:general planets and satellites:formation planets and satellites:physical evolution
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2015/12/25
We carry out a systematic exploration of the effect of pre-impact rotation on the outcomes of low-speed collisions between planetesimals modeled as gravitational aggregates. We use pkdgrav, a cosmolog...
Collision and gravitational reaccumulation:Possible formation mechanism of the asteroid Itokawa
gravitation methods:numerical minor planets asteroids:general minor planets asteroids:individual:Itokawa
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2015/12/25
Aims: We investigate the possibility that the observed sea-otter shape of the asteroid Itokawa, associated with the presence of big boulders on its surface, originates from the reaccumulation process ...