地球化学新方法在隐状矿床找矿预测中的应用研究

With the progress of prospecting, the need for the discovery of blind ore deposits become more and more urgent. To study and find out the method and technology for the discovery of blind and buried ores is now a priority task. New geochemical methods are key technology to discover blind ores. Information of mobile components related to blind ores were extracted using this new methods. These methods were tested and applied based on element' s mobile components migrating and enriched in geophysical-geochemical process. Several kinds of partial extraction techniques have tested based on element' s occurrence in hypergenic zone. Middle-large scale geochemical methods for exploration in forest and swamp have been tested. A serious of methods were tested and applied effetely about evaluation of regional geochemical anomaly, 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system instead of the normal net. 1. Element related with ores can be mobiled to migrate upwards and be absorpted by surface soil. These abnomal components can be concentrated by natural or artificial methods. These trace metalic ions partially exist in dissovlvable ion forms of active state, and partially have been absorbed by Fe-Mn oxide, soil and organic matter in the soil so that a series of reaction such as complex reaction have take place. Employing various partial extraction techniques, metallic ions related with the phase of the blind ores can be extracted, such as the technique of organic complex extraction, Fe-Mn oxide extraction and the extraction technique of metallic ions of various absorption phases. 2.1:200000 regional geochemical evaluation anomaly methods: Advantageous ore-forming areas were selected firstly. Center, concentration, morphological feature, belt of anomaly were choosed then. Geological and geochemical anomalies were combined. And geological and geochemical background information were restrained. Xilekuduke area in Fuyun sheet , Zhaheba area in Qiakuerte sheet, the west-north part in Ertai sheet and Hongshanzui anomaly in Daqiao sheet were selected as target areas, in Alertai, in the north of Xinjiang. in Xilekuduke area, 1:25000 soil geochemical methods sampling based on the net in dendritic water system was carried out. Cu anomaly and copper mineralization were determined in the center area. Au , Cu anomalies and high polarization anomaly were determined in the south part. Prospecting by primary halo and organic complex extraction were used to prognosis blind ore in widely rang outcrop of bedrock. 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system were used in transported overburden outside of mining area. Shallow seismic method and primary halo found a new blind orebody in mining area. A mineralization site was fou and outside of Puziwan gold mine, in the north of Shanxi province. Developing middle-large scale geochemical exploration method is a key technique based 1:200000 regional geochemical exploration. Some conditions were tested as Sampling density , distribution sites of sample, grain size of sample and occurrence of element for exploration. 1:50000 exploration method was advanced to sample clast sediment supplement clast sediment in valley. 1:25000 bedrock or soil geochemical methods sampling based on the net in dendritic water system was applied to sample residual material in A or C horizon. 1:2000 primary or soil halo methods used to check anomalies and determine mineralization. Daliang gold mineralization in the northern Moerdaoga was found appling these methods. Thermomagnetic method was tested in miniqi copper-polymetallic ore. Process methods such as grain size of sample, heated temperature, magnetic separating technique were tested. A suite of Thermomagnetic geochemical method was formed. This method was applied in Xiangshan Cu~Ni deposit which is cover by clast or Gobi in the eastern Xinjiang. Element's content and contrast of anomaly with Thermomagnetic geochemical method were higher than soil anomaly. Susceptibility after samples were heated could be as a assessment conference for anomaly. In some sectors thermo-magnetic Cu, Ni, Ti anomalious were found outside deposits area. There were strong anomal ies response up ore tested by several kind of partial extraction methods include Thermomagnetic, enzyme leach and other partial extractions in Kalatongke Cu-Ni deposit in hungriness area in the northern of Xinjiang. Element's anomalies of meobile were mainly in Fe-Mn oxide and salt. A Copper mineralization site in Xilekuduke anomaly area had been determined. A blind ore was foung by shallow seismic and geochemical method and a mineralization site was found outside this mining area in Puziwan gold deposit in shanxi province. A Gold mineralization site was found by 1:50000 geochemical exploration in Daliang, Inner Mongolia.

The effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system

We investigate the effects of nonlinear couplings and external magnetic field on the thermal entanglement in a two-spin-qutrit system by applying the concept of negativity. It is found that the nonlinear couplings favor the thermal entanglement creating. Only when the nonlinear couplings vertical bar K vertical bar are larger than a certain critical value does the entanglement exist. The dependence of the thermal entanglement in this system on the magnetic field and temperature is also presented. The critical magnetic field increases with the increasing nonlinear couplings constant vertical bar K vertical bar. And for a fixed nonlinear couplings constant, the critical temperature is independent of the magnetic field B. (c) 2005 Elsevier B.V. All rights reserved.

两层流体热毛细对流空间实验研究=Space Experiments of Thermo Capillary Convection in Two-liquid Layers

1999年,在我国实践5号卫星上完成了两层流体空间实验,实验研究两层不相混合流体的纯Marangoni对流（温度梯度与界面垂直）与热毛细对流（温度梯度方向与流体界面平行）.前者存在发生Marangoni对流的最小临界温差值△Tc,低于该值流体系统处于静止状态;后者中只要存在沿界面的温度梯度便会产生热毛细对流.空间实验采用石蜡和氟化液两层流体新体系,实现了平整的液-液交界面,并从卫星上传回上万幅数字图像.通过多幅图像叠加处理得到了定量的流速场.数值模拟计算分析了相应工况时对流流动的速度场,两者的流场结构和速度大小基本一致,实验验证了理论模型.

Influence of Local Magnetic Fields on P-Doped Si Floating Zone Melting Crystal Growth in Microgravity

A two-dimensional axisymmetric numerical model is presented to study the influence of local magnetic fields on P-doped Si floating zone melting crystal growth in microgravity. The model is developed based on the finite difference method in a boundary-fitted curvilinear coordinate system. Extensive numerical simulations are carried out, and parameters studied include the curved growth interface shape and the magnetic field configurations. Computed results show that the local magnetic field is more effective in reducing the impurity concentration nonuniformity at the growth interface in comparison with the longitudinal magnetic field. Moreover, the curved growth interface causes more serious impurity concentration nonuniformity at the growth interface than the case with a planar growth interface.

The thermo-visco-plastic instability analysis of saturated soil

A theoretical analysis of instability of saturated soil is presented considering the simple shearing of a heat conducting thermo-visco-plastic material. It is shown that the instability is mainly the consequence of thermal softening which overcomes the strain hardening and the other type of instability is controlled by strain softening. The effects of other factors such as permeability to the instability are discussed in this paper.

Microstructure and Magnetic Properties of Nd60Al10Fe20Co10 Glass-forming Alloy

The microstructural variations of the Nd60Al10Fe20CO10 melt-spun ribbons and the as-cast rod were studied by high resolution transmission electron microscopy (HRTEM), x-ray diffraction (XRD) and differential scanning calorimetry. Nano-clusters in glassy m

Effect of non-uniform magnetic field on crystal growth by floating-zone method in microgravity

The magnetic damping effect of the non-uniform magnetic field on the floating-zone crystal growth process in microgravity is studied by numerical simulation. The results show that the non-uniform magnetic field with designed configuration can effectively reduce the flow near the free surface and then in the melt zone. At the same time, the designed magnetic field can improve the impurity concentration non-uniformity along the solidification interface. The primary principles of the magnetic field configuration design are also discussed.

Glass transition and crystallization process of hard magnetic bulk Nd60Al10Fe20Co10 metallic glass

Glass transition and crystallization process of bulk Nd60Al10Fe20Co10 metallic glass were investigated by means of dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electronic microscopy (SEM). It is shown that the glass transition and onset crystallization temperature determined by DMTA at a heating rate of 0.167 K/s are 480 and 588 K respectively. The crystallization process of the metallic glass is concluded as follows: amorphous alpha-->alpha' + metastable FeNdAl novel phase -->alpha' + primary delta phase-->primary delta phase + eutectic delta phase Nd3Al phase + Nd3Co phase. The appearance of hard magnetism in this alloy is ascribed to the presence of amorphous phase with highly relaxed structure. The hard magnetism disappeared after the eutectic crystallization of amorphous phase.

Magnetic properties and magnetic domain structure of bulk glass forming Nd60Al10Fe20Co10 alloy

The transition from hard to soft magnetic behaviour with increasing quenching rate is shown for Nd60WAl10Fe20Co10 melt-spun ribbons with different thickness. Microstructure and magnetic domain structure of ribbons were studied by magnetic force microscopy (MFM). Particle sizes < 5 nm decreasing gradually with increasing quenching rate were deduced from topographic images which differ from large-scale magnetic domains with a periodicity of about 350 nm in all ribbons irrespective the coercivity. This indicates that the magnetic properties of the alloy are governed by interaction of small magnetic particles. It is concluded that the presence of short-range-ordered structures with a local ordering similar to the Al metastable Nd-Fe binary phase is responsible for the hard magnetic properties in samples subjected to relatively low quenching rate.

Numerical simulation of magnetic field design for damping thermocapillary convection in a floating half-zone

The magnetic fields produced by electrical coils are designed for damping the the thermocapillary convection in a floating half-zone in microgravity. The fields are designed specially to reduce the flow near the free surface and then in the melt zone by adjusting the longitudinal coil positions close to the melt zone. The effects of the designed magnetic fields on reducing the flow velocity and temperature distribution non-uniformity in the melt zone are stronger than those of the case of an uniform longitudinal magnetic field obtained by numerical simulation, particularly at the melt-rod interface. It brings fundamental insights into the heat and mass transfer control at the solidification interface by the magnetic field design for crystal growth by the floating full-zone method.

Domain structure of hard magnetic NdAlFeCo bulk metallic glass

Magnetic domain structure of hard magnetic Nd60Al10Fe20Co10 bulk metallic glass (BMG) has been studied by using magnetic force microscopy. In the magnetic force images it is shown that the exchange interaction type magnetic domains with a period of about 360 nm do exist in the BMG, which is believed to be associated with the appearance of hard-magnetic properties in this system. As the scale of the magnetic domain is much larger than the size of the short-range ordered atomic clusters existing in the BMG, it is believed that the large areas of magnetic contrast are actually a collection of a group of clusters aligned in parallel by strong exchange coupling interaction. After fully crystallization, the BMG exhibits paramagnetism. No obvious magnetic contrast is observed in the magnetic force images of fully crystallized samples, except for a small quantity of ferromagnetic crystalline phase with low coercivity and an average size of 900 nm.

Magnetic field design for floating zone crystal growth

The magnetic fields produced by electrical coils are designed for P-doped Si crystal growth in a floating full zone in microgravity environment. The fields are designed specially to reduce the how near the free surface and then in the melt zone by adjusting the coil positions near the melt zone. The effects of the designed magnetic fields on reducing the Row velocity and the non-uniformity of the concentration distribution in the melt zone are better than those of the case of a uniform longitudinal magnetic field, obtained by numerical simulation. It is expected to improve the radial macro-segregation and reduce the convection in the crystal growth at the same time by using the designed magnetic field.

Numerical Analysis of LEC Growth of GaAs with an Axial Magnetic Field

A set of numerical analyses for momentum and heat transfer For a 3 in. (0.075 m) diameter Liquid Encapsulant Czochralski (LEC) growth of single-crystal GaAs with or without all axial magnetic field was carried Out using the finite-element method. The analyses assume a pseudosteady axisymmetric state with laminar floats. Convective and conductive heat transfers. radiative heat transfer between diffuse surfaces and the Navier-Stokes equations for both melt and encapsulant and electric current stream function equations Cor melt and crystal Lire considered together and solved simultaneously. The effect of the thickness of encapsulant. the imposed magnetic field strength as well as the rotation rate of crystal and crucible on the flow and heat transfer were investigated. (C) 2002 Published by Elsevier Science Ltd.

Relation between Stabilization Energy, Crystal Field Coefficient and the Magnetic Exchange Interaction for Tb3+ Ion

Based on a single ion model, Hamiltonian of the simplest form about magnetocrystalline anisotropy for Tb3+ ion was solved by using the numerical method. The relation between the stabilization energy, crystal field coefficient B-2(0) and the magnetic exchange interaction was studied as temperature approaches to 0 K. The results show that the stabilization energy contributed by Tb3+ is linear with crystal field coefficient B-2(0) approximately, but it is insensitive to the change of magnetic exchange interaction for the strong magnetic substances such as TbCo5, Tb2Co17 and Tb2Fe14B compounds.

Phase Evolution and its Effect on Magnetic Properties of Nd60Al10Fe20Co10 Bulk Metallic Glass

The thermal stability of nanocrystalline clusters, the phase evolution, and their effects on magnetic Propertieswere studied for as-cast Nd60Al10Fe20Co10 alloy using differential scanning calorimetry curves, x-ray diffraction patterns, scanning electron microscopy, and high-resolution transition electron microscopy. Thermomagnetic curves and hysteresis loops of the bulk metallic glass were measured during the annealing process. The high thermostability of the hardmagnetic properties of the samples observed is attributed to the stability of the nanocrystalline clusters upon annealing, while the slight enhancement in the magnetization is due to the precipitation of some Nd-rich metastable phases. The mechanism of thermostability of the nanocrystalline clusters and the formation of the metastable phases are discussed.