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1.
西秦岭温泉花岗岩体岩石学特征及岩浆混合标志 总被引:14,自引:5,他引:9
温泉花岗岩体由酸性端元的寄主岩石和暗色微细粒镁铁质包体群及基性岩墙群组成。无岩浆混合作用或岩浆混合作用较弱区段,寄主岩石以似斑状二长花岗岩为主.显示正常的花岗岩结构构造岩浆混合作用强烈区段。岩石的异常结构构造十分发育.矿物之间自形程度差异显著.常见包晶反应、包含结构、交代边、熔蚀边、交代蚕食的港湾状结构构造及交代缝合线、矿物镶边、斜长石异常环带和矿物残留等,多见指示岩浆混合的标志性矿物针状磷灰石。暗色微粒包体中多见寄主二长花岗岩中的捕掳晶。包体的形态、结构构造以及与寄主岩石强烈地成分交换等均是岩浆混合作用的标志。 相似文献
2.
史生才 《紫金山天文台台刊》2003,(1)
为了研制亚毫米波射电天文用超导SIS(超导 -绝缘体 -超导 )接收机 ,我们重点开展了如下研究 ,1 )Nb超导SIS结在其能隙频率附近的量子混频特性 ,及其结合高能隙超导薄膜 (NbTiN)和高电导率金属薄膜 (Al)分布结阵在 780 - 950GHz频率区间的量子混频特性 ;2 )亚毫米波超导混频器嵌入阻抗的数值和实验表征 ;3)高电流密度小面积Nb超导SIS结的制备和特性表征 ;4)一个 60 0 - 72 0GHz超导SIS混频器的研制和特性表征。本文详细介绍了相关的数值分析和实验测量结果。 相似文献
3.
从知道某些天体具有磁场起,人们就对其磁场的起源提出种种解释,例如有电池说,转子说,化石说,发电机说等等。但由于这些学说都分别与某些观测事实相抵触而未被公认,因此星球磁场的起源一直是未能解决的命题。余先河先生提出,星球的磁场起源可能与所受的引力有关,行星的磁场强度正比于其所受卫星的引力;正比于卫星与行星的引力连线转动的相对角速度。本文对这两方面的命题分别进行了相关分析,得到其相关系数分别为:r=0.8481和r=0.8425,它们都在a=0.01的信度水平上相关。结果表明余新河关于行星磁场起源的设想是有基础的。本文还对其统计结果和可能机制进行了讨论。 相似文献
4.
Tidal effects on temperature front in the Yellow Sea 总被引:5,自引:0,他引:5
Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring, thrives in summer, and fades
in autumn as thermocline declines. TF intensity ⋎S
T
⋎ is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution
in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results
are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming
and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the
TF.
Supported by the National Basic Research Program of China (No. G1999043809) and the National Science Foundation of China (No.
49736190). 相似文献
5.
Cold water in the deep Pacific can be drawn up to the surface (or west warm water drifts eastwards ) because strong tide increases the mixing of seawater both in vertical and horizontal. In this way greenhouse effect is decreased or increased by means of absorbing (or releasing) CO2. Therefore, La Nina cold event (or El Nino warm event) may occur,which is caused by wanning - up or cooling - down air above the ocean. Volcanic action at sea bottom is also controlled by strong tide. 相似文献
6.
7.
Lightning discharge generated in the protoplanetary nebula is viewed as a temporally isolated surge in the flow of electrically charged particles, similar to that of terrestrial lightning. If the current is intense enough, a powerful circular impulse magnetic field is generated around the instantaneous virtual electric conductor. Such magnetic field is capable of magnetizing dust grains containing ferromagnetic components present in its vicinity to their saturation levels. As a result, dust grains attract one another, forming the aggregates. This magnetically driven attraction suggests an important process possibly operational at an early stage of the planetary accretion. Based on both a classical model for electric conductor, and the theory of Lienard–Wiechert electromagnetic potentials, our calculations show that the magnetic impulse due to a discharge channel of a few cm in diameter transferring a charge of about 104 electrons reaches as high as 10 T. At these magnetic fields, the ferromagnetic dust grains, and possibly the already-formed larger aggregates as well, are easily magnetized to the saturation levels, producing compact clusters exhibiting permanent magnetic moments. 相似文献
8.
近年来月球探测已经进入了一个全新的时代。特别是 1 990年以来 ,多个月球探测计划已经被成功实现 ,而且另外还有多个探测计划也在准备当中 ,并将在未来的几年内发射升空。在这种背景之下 ,中国的航天机构和有关的科学家也开始积极酝酿和开发自己的月球探测计划。这些月球探测计划将利用卫星上搭载的各种仪器探测和测量月球的地质和地理特性、化学成分和矿物组成、月球物理学特征以及包含地球大气在内的地月空间环境和行星际空间环境 ;进一步研究月球的起源和演化 ,探明月面环境 ,研究太阳等离子体物理 ,提供月面天文台和月面长期科研基地的候选地址 ,调查月球上的可利用资源 ,为将来开发月球提供充实的背景资料。参与新一轮的月球探测同样也为中国天文学研究带来了新的机会。 相似文献
9.
本文论述了保安地区火山岩的地质、岩石、副矿物、岩石化学、微量元素、稀土元素、稳定同位素、火山岩相及火山机构等特征。并对其演化规律、形成机制与成矿作用的关系,作了初步探讨。 相似文献
10.
O. Sadot K. Levy A. Yosef-Hai D. Cartoon Y. Elbaz Y. Srebro G. Ben-Dor D. Shvarts 《Astrophysics and Space Science》2005,298(1-2):305-312
The hydrodynamic instability, which develops on the contact surface between two fluids, has great importance in astrophysical
phenomena such as the inhomogeneous density distribution following a supernova event. In this event acceleration waves pass
across a material interface and initiate and enhance unstable conditions in which small perturbations grow dramatically.
In the present study, an experimental technique aimed at investigating the above-mentioned hydrodynamic instability is presented.
The experimental investigation is based on a shock-tube apparatus by which a shock wave is generated and initiates the instability
that develops on the contact surface between two gases. The flexibility of the system enables one to vary the initial shape
of the contact surface, the shock-wave Mach number, and the density ratio across the contact surface.
Three selected sets of shock-tube experiments are presented in order to demonstrate the system capabilities: (1) large-initial
amplitudes with low-Mach-number incident shock waves; (2) small-initial amplitudes with moderate-Mach-number incident shock
waves; and (3) shock bubble interaction.
In the large-amplitude experiments a reduction of the initial velocity with respect to the linear growth prediction was measured.
The results were compared to those predicted by a vorticity-deposition model and to previous experiments with moderate- and
high-Mach number incident shock waves that were conducted by others. In this case, a reduction of the initial velocity was
noted. However, at late times the growth rate had a 1/t behavior as in the small-amplitude low-Mach number case. In the small-amplitude moderate-Mach number shock experiments a
reduction from the impulsive theory was noted at the late stages.
The passage of a shock wave through a spherical bubble results in the formation of a vortex ring. Simple dimensional analysis
shows that the circulation depends linearly on the speed of sound of the surrounding material and on the initial bubble radius. 相似文献