液核地球CIP轴的极移和岁差章动

基于经典的液核地球自转动力学理论,通过引入章动参考系相对惯性空间的运动,建立了液核地球极移和章动的联合动力学方程,由此对CIP轴进行了理论定义,并给出了其极移、岁差和章动的动力学方程,在顾及到5阶岁差章动力矩的情况下,给出了岁差章动的解析表达式,通过推导发现,即使没有核幔边界的耗散耦合,奇数阶岁差章动力矩也使得黄经章动和交角章动出现了异向项,即黄经章动出现了cos项,交角章动出现了sin项,同时还证明了岁差表达式与地球模型无关,本的理论可为动力大地测量学和天地球动力学的研究提供理论参考和依据。     

液核地球极移和章动的联合动力学方程

以经典的液核地球自转动力学理论为基础,通过引入章动坐标系相对惯性空间的运动,建立了液核地球极移和章动的联合动力学方程。主要内容有：（1）顾及了高阶岁差章动力矩对地球自转的影响;（2）引入了摄动周期满足T≤2/3d和T≥2d的其他因素（大气、海洋和地表水分布变化等）对地球自转的影响;（3）建立了自转轴极移和任一天球参考轴极移和章动之间的理论关系;（4）建立了液核地球极移和章动的联合动力学方程,试图用统一的方法研究极移和章动。作者给出的理论公式可为动力大地测量学和天文地球动力学的研究提供理论参考和依据。     

三轴液核地球自转的动力学方程

整体地球自转动力学的理论研究一般是在旋转对称模型基础上进行的,并得到了一系列与观测相符合的结论.但实际上地球是一个非旋转对称的椭球体,甚至是梨形椭球体.因此,三轴地球模型的自转理论研究应该是具有一定意义的.在所有量保留到极移平方量级而忽略其更小量级的情况下,给出了三轴液核地球自转的动力学方程.研究指出,在此精度上三轴液核地球自转的动力学方程是线性耦合的,并得到了三轴液核地球自转的4个本征频率.同时指出,如果在推导过程中保留更小量级,则液核地球自转动力学方程是复杂的非线性方程组,它没有解析解.     

弹性地球极移和章动的联合动力学方程

基于经典的弹性地球自转动力学理论，通过引入章动坐标系相对惯性空间的运动，推导出一个同时包含极移和章动的弹性地球自转联合动力学方程。在推导过程中首次考虑了高阶岁差章动力矩和其它摄动因素(摄动周期满足0．5d≤T≤1．5d)对地球自转的影响，从而使得方程更加完备和完美，与现行的地球自转动力学方程相比较表明，该方法综合性强而且易于理解。     

刚体地球极移和章动的联合动力学方程

以经典的刚体地球自转欧拉动力学理论为基础,通过引入章动坐标系相对惯性空间的运动,推导出了一个同时包含极移和章动的刚体地球自转联合动力学方程。在推导过程中首次考虑了高阶岁差章动力矩(摄动周期满足2d/3相似文献   

地球内核的动力学理论及章动效应

 地球固体内核与其其余部分之间的引力和压力的耦合作用将引起一内力矩,内核通过这一力矩影响岩石圈相对惯性空间的定向.讨论了一个弹性无海洋、球形分层的内核地球章动理论,将内核的作用明确地反映在公式中.并依据Mathews et al的内核地球动力学理论,讨论了归一化章动振幅的Mathews形式和Wahr形式的应用;通过PREM地球模型检测了内核对章动振幅的影响,由此发现本文的结果与Mathews et al的结果存在一定的差异,但都在亚毫角秒量级上影响主要的圆章动项.     

弹性地球CIP轴的极移和岁差章动

基于经典的弹性地球自转动力学理论,通过引入章动参考系相对惯性空间的运动,建立了弹性地球极移和章动的联合动力学方程。由此对 CIP 轴进行了理论定义,并给出了其极移、岁差章动的动力学方程。在顾及到 5 阶引潮力矩的情况下,给出了 CIP 轴的岁差章动的解析表达式。理论研究表明,奇数阶岁差章动力矩使得黄经章动和交角章动出现了异向项（即黄经章动出现了 cos 项,交角章动出现了 sin 项）,同时也证明了岁差表达式与地球模型无关。得出的理论可为动力大地测量学和天文地球动力学的研究提供理论参考和依据。     

2008年冬季—2009年春季干旱的大气结构与地球转动特征

针对干旱预测的难题,利用揭示大气热结构垂直特征的V-3θ图,分析影响旱区的气流特征。根据国际地球自转服务（IERS）的数据,分析地球极移、章动和转速的变化与大气热结构变化的关系,基于地气动量守恒原理,将大气热结构与地球转动特征变化进行了制约性分析。结果表明,大气热结构异常和地球转动特征引起的冷空气路径变化与大范围干旱有关。     

地球外核液体的子午面对流

阐述了地球外核液体午面对流的原因，导出了流速方程，并模拟了流体运动图象。     

高能核─核碰撞的椭球状衰变模型与核阻止本领

提出一种椭球状衰变的模型，分析了目前高能区核─核碰撞的核阻止本领对入射能量和碰撞核质量依赖关系。     

Evidence for an oxygen-depleted liquid outer core of the Earth

On the basis of geophysical observations, cosmochemical constraints, and high-pressure experimental data, the Earth's liquid outer core consists of mainly liquid iron alloyed with about ten per cent (by weight) of light elements. Although the concentrations of the light elements are small, they nevertheless affect the Earth's core: its rate of cooling, the growth of the inner core, the dynamics of core convection, and the evolution of the geodynamo. Several light elements-including sulphur, oxygen, silicon, carbon and hydrogen-have been suggested, but the precise identity of the light elements in the Earth's core is still unclear. Oxygen has been proposed as a major light element in the core on the basis of cosmochemical arguments and chemical reactions during accretion. Its presence in the core has direct implications for Earth accretion conditions of oxidation state, pressure and temperature. Here we report new shockwave data in the Fe-S-O system that are directly applicable to the outer core. The data include both density and sound velocity measurements, which we compare with the observed density and velocity profiles of the liquid outer core. The results show that we can rule out oxygen as a major light element in the liquid outer core because adding oxygen into liquid iron would not reproduce simultaneously the observed density and sound velocity profiles of the outer core. An oxygen-depleted core would imply a more reduced environment during early Earth accretion.     

轴对称电磁能流模型及其缺限

通过建立轴对称电容器模型，建立了能量流图像，定量分析了电容器内能量变化与能流的关系，指出了模型本身的物理缺限．     

Accretion of the Earth and segregation of its core

The Earth took 30-40 million years to accrete from smaller 'planetesimals'. Many of these planetesimals had metallic iron cores and during growth of the Earth this metal re-equilibrated with the Earth's silicate mantle, extracting siderophile ('iron-loving') elements into the Earth's iron-rich core. The current composition of the mantle indicates that much of the re-equilibration took place in a deep (> 400 km) molten silicate layer, or 'magma ocean', and that conditions became more oxidizing with time as the Earth grew. The high-pressure nature of the core-forming process led to the Earth's core being richer in low-atomic-number elements, notably silicon and possibly oxygen, than the cores of the smaller planetesimal building blocks.     

城市核心竞争力识别系统分析模型

针对城市核心竞争力要素识别这一复杂系统问题,采用系统分析的方法,从经济学与战略管理两个角度对城市核心竞争力要素进行了界定,指出城市核心竞争力要素具有整合性和独特性双重特点,整合性包括协调性、功能交叉和集聚性,独特性包括价值性、稀缺性、不可模仿性、不可替代性和拓展性.在此基础之上,建立了识别城市核心竞争力要素的二维决策矩阵模型.最后,通过将该二维决策矩阵模型应用到某一沿海港口城市核心竞争力要素识别实例中,说明该城市核心竞争力识别模型的科学性和有效性.     

Partitioning of oxygen during core formation on the Earth and Mars

Core formation on the Earth and Mars involved the physical separation of metal and silicate, most probably in deep magma oceans. Although core-formation models explain many aspects of mantle geochemistry, they have not accounted for the large differences observed between the compositions of the mantles of the Earth (approximately 8 wt% FeO) and Mars (approximately 18 wt% FeO) or the smaller mass fraction of the martian core. Here we explain these differences as a consequence of the solubility of oxygen in liquid iron-alloy increasing with increasing temperature. We assume that the Earth and Mars both accreted from oxidized chondritic material. In a terrestrial magma ocean, 1,200-2,000 km deep, high temperatures resulted in the extraction of FeO from the silicate magma ocean owing to high solubility of oxygen in the metal. Lower temperatures of a martian magma ocean resulted in little or no extraction of FeO from the mantle, which thus remains FeO-rich. The FeO extracted from the Earth's magma ocean may have contributed to chemical heterogeneities in the lowermost mantle, a FeO-rich D" layer and the light element budget of the core.     

Cooling of the Earth and core formation after the giant impact

Kelvin calculated the age of the Earth to be about 24 million years by assuming conductive cooling from being fully molten to its current state. Although simplistic, his result is interesting in the context of the dramatic cooling that took place after the putative Moon-forming giant impact, which contributed the final approximately 10 per cent of the Earth's mass. The rate of accretion and core segregation on Earth as deduced from the U-Pb system is much slower than that obtained from Hf-W systematics, and implies substantial accretion after the Moon-forming impact, which occurred 45 +/- 5 Myr after the beginning of the Solar System. Here we propose an explanation for the two timescales. We suggest that the Hf-W timescale reflects the principal phase of core-formation before the giant impact. Crystallization of silicate perovskite in the lower mantle during this phase produced Fe(3+), which was released during the giant impact, and this oxidation resulted in late segregation of sulphur-rich metal into which Pb dissolved readily, setting the younger U-Pb age of the Earth. Separation of the latter metal then occurred 30 +/- 10 Myr after the Moon-forming impact. Over this time span, in surprising agreement with Kelvin's result, the Earth cooled by about 4,000 K in returning from a fully molten to a partially crystalline state.     

粘弹流体中Giesekus模式和Oldroyd模式的改进

详细研究了粘弹性流体的Ｇｉｅｓｅｋｕｓ和Ｏｌｄｒｏｙｄ两类重要模式,给出了它们本构方程的新表达形式,并对模式的特点进行了分析。文中采用分区覆盖算法对两种模式在Ｗｅ＝２．９的高Ｗｅｉｓｓｅｎｂｅｒｇ数下进行了大量的数值计算并与有关实验数据进行了细致的比较。数值计算表明两种模式在本文采用的分区覆盖算法下均能得到Ｗｅ＝２．９的收敛解,而且修改的Ｏｌｄｒｏｙｄ模式比Ｇｉｅｓｅｋｕｓ模式更贴近实验值。     

轴线为任意曲线曲梁的数值分布传递函数解

对于轴线为任意曲线的曲梁,通过多项式插值计算将曲梁的曲线方程表示出来,并转换为以弧坐标s为参变量的函数。基于曲梁的挠曲线微分方程,建立曲梁系统的数值分布传递函数求解模型。