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991.
在系统地分析了目前各种测震学地震预报方法科学思路的基础上,认为测震学地震预报方法基本上可以分为两大类。一类是以已经发生的一些地震作为未来可能发生的地震的“因”,即由于已经发生的地震对区域应力场的影响,导致未来发生较强地震。这一类包括的预报方法较多,如空区、条带、b值、地震迁移、相关地震等等及其由此衍生出来的各种方法。另一类是把已经发生的一些地震作为区域应力场增强的“果”,即已经发生的地震是区域应力场增强过程中的一种反映,而未来地震不一定是已经发生的地震所导致的结果。这一类包括“地震窗口”、小震群活动等方法。针对第一类方法,各种预报方法都是力图从地震三要素中提取未来地震的信息,而具体作法又都是利用地震三要素这个多维空间的某个剖面。为了从地震活动诸要素的多维空间提取综合信息,我们对每个地震加入了破裂面方位,构成了地震第四要素,并依据地震4要素建立了地震综合效应场函数。地震综合效应场函数概括了多种测震学地震预报方法的科学思路和预报经验,从而可以形成测震学的综合预报方法。  相似文献   
992.
大别山榴辉岩一片麻岩杂岩的成因   总被引:2,自引:1,他引:1  
大别山榴辉岩由辉长岩、大陆拉斑玄武岩和少量泥灰质经高压变质作用形成。大别地块可划分出四个形成条件不同的榴辉岩区,它们代表一种构造-岩石组合体。片麻岩杂岩中各种高压变质岩类的发现证明它们与榴辉岩一起经历了原地高压变质过程。二者变质作用P-T参数的差异归因于抬升过程中退变质反应速度的不同。不同地区榴辉岩退变质组合及P-T条件与围岩的一致性表明,大别杂岩现今所展示的“递增”变质带是由榴辉岩相退变质作用形成的。高压榴辉岩-片麻岩杂岩的产生是印支期扬子与华北两个大陆板块碰撞的结果。  相似文献   
993.
“雅安天漏”研究 III:特征、物理量结构及其形成机制   总被引:9,自引:5,他引:4  
本文的这一部分首先进一步分析了第二部分的预报结果,结果发现,在本文第二部分所建立的模式,不仅较好地预报出了24小时总降水量,而且也较好地预报出了“雅安天漏”的降水特征和降水中的物理结构。模式基本上抓住了形成雅安降水的主要影响因子。然后通过一系列精心设计的数值模拟试验得到了形成雅安降水的可能机制。  相似文献   
994.
Wang  Yutian  Tan  Bingqi  Wang  Yifeng  Wu  Jiangtao 《Natural Resources Research》1994,3(4):284-294
We propose an information-structure-analysis (ISA) method to quantify the correlations between quantitative and qualitative variables as well as within each type of variable. This method is applied to the evaluation of mineral resources in the western Zheijiang Province of China. The district contains a number of silver-bearing Fe–Cu–Pb–Zn mineral deposits near igneous complexes and FeCuPbZn zones away from the complexes. Silver anomalies occur not only in the known Fe–Cu–Zn–Pb deposits, but also in the country rock, suggesting the possible existence of silver deposits far from the igneous complexes.The tonnage distribution of silver is modeled by Monte Carlo simulation. This simulation is conducted on the basis of the correlations between silver (Ag) and lead (Pb), since no known data on silver is available. The known tonnage distribution of lead in 11 control cells was used to approximate the tonnage distribution of silver in the Monte Carlo simulation. With ISA and Monte Carlo methods, the total amount of potential polymetallic resources in 49 cells in the western Zhejiang Provice is predicted. Significantly, a deposit with about 24 tonnes of silver has been found within our exploration target area.  相似文献   
995.
We have started a program of high-resolution (0.4/pixel) 10m imaging of bipolar outflow sources using the 10m camera CAMIRAS. We present recent results obtained at the Canada France Hawaii Telescope which reveal extended emission or IR companions in several luminous objects. The extended emission we detected probably arises from transiently heated very small grains, while the newly discovered companions could contribute significantly to the outflow activity and extended far-IR emission usually attributed to the main optical source.  相似文献   
996.
We study some simple periodic orbits and their bifurcations in the Hamiltonian . We give the forms of the orbits, the characteristics of the main families, and some existence diagrams and stability diagrams. The existence diagram of the family 1a contains regions that are stable (S), simply unstable (U), doubly unstable (DU) and complex unstable (). In the regionsS andU there are lines of equal rotation numberm/n. Along these lines we have bifurcations of families of periodic orbits of multiplicityn. When these lines reach the boundary of the complex unstable region, they are tangent to it. Inside the region there are linesm/n, along which the orbits 1a, describedn-times, are doubly unstable; however, along these lines there are no bifurcations ofn-ple periodic orbits. The families bifurcating from 1a exist only in certain regions of the parameter space (, ). The limiting lines of these regions join at particular points representing collisions of bifurcations. These collisions of bifurcations produce a nonuniqueness of the various families of periodic orbits. The complicated structure of the various bifurcations can be understood by constructing appropriate stability diagrams.  相似文献   
997.
The scope of the present paper is to provide analytic solutions to the problem of the attitude evolution of a symmetric gyrostat about a fixed point in a central Newtonian force field when the potential function isV (2).We assume that the center of mass and the gyrostatic moment are on the axis of symmetry and that the initial conditions are the following: (t 0)=0, (t 0)=0, (t 0)=(t 0)=0, 1(t 0)=0, 2(t 0)=0 and 3(t 0)= 3 0 .The problem is integrated when the third component of the total angular momentum is different from zero (B 1 0). There now appear equilibrium solutions that did not exist in the caseB 1=0, which can be determined in function of the value ofl 3 r (the third component of the gyrostatic momentum).The possible types of solutions (elliptic, trigonometric, stationary) depend upon the nature of the roots of the functiong(u). The solutions for Euler angles are given in terms of functions of the timet. If we cancel the third component of the gyrostatic momentum (l 3 r =0), the obtained solutions are valid for rigid bodies.  相似文献   
998.
We have used the ESO 10 m camera, TIMMI, to image with a very high angular resolution (PFoV: 0.3; FWHM:0.9) several main-sequence star disk candidates. Information on the -Pictoris dust disk has been obtained in a region largely inaccessible to previous observations: 0–80 AU, with a resolution of about 5 AU after deconvolution. Another promising target for 10 m imaging, 51 Ophiuchi, appears point-like.based on data collected at the European Southern Observatory (ESO), La Silla, Chile  相似文献   
999.
The photodegradation of naphthalene (NPH), chosen as a model of polynuclear aromatic pollutants, has been studied in the presence of a layer of four water-insoluble inorganic solids which can be found in the troposphere (TiO2, Fe2O3, muscovite, and a fly ash sample). Direct photolysis of NPH is negligible at >340 nm. Dark adsorption of NPH on TiO2 (mainly anatase, nonporous, 50 m2 g–1) at 293 K corresponds to a surface coverage ofca. 50% at equilibrium. Under these conditions (saturated surface), the stationary-state photocatalytic degradation reaches 0.4 molecule nm–2 h–1 (>340 nm, radiant fluxca. 22 mW cm–2). Dioxygen is required and its partial pressure in air is such that the degradation is zero order in O2. Water vapor markedly increases the rate. The other particulates have also an effect, less important than that of TiO2, however quite noticeable with respect to surface area unit for the fly ash sample which contains 3.2% Fe2O3. Apart from 1,4-naphthoquinone, which is the main intermediate product in all cases, 2-naphthol, phthalide, phthaldialdehyde, phthalic acid, acetophenone, benzaldehyde, benzoic acid are also formed on dry TiO2. Depending on their volatility, these compounds are transferred to the gas phase or remain principally adsorbed on the solid particles where they are further transformed. For instance, phthalic acid (or anhydride) and benzoic acid are generated from 1,4-naphthoquinone. Degradation mechanisms are briefly discussed.  相似文献   
1000.
An experimental study is described of Fe(III)-S(IV) formation constants measured as a function of pH (1–3), ionic strength (0.2–0.5 M) and [Fe(III)] T (2.5–5.0×10–4 M) using a continuous-flow spectrophotometric technique to make observations 160 ms after mixing. Preliminary experiments using pulse-accelerated-flow (PAF) spectrophotometry to measure rate constants on a microsecond timescale are also described. The conditional formation constant at 25 °C can be modeled with the following equation: {ie307-1} where {ie307-2}K 7 andK 8 can be interpreted as intrinsic constants for the coordination of HSO 3 by FeOH2+ and Fe3+, respectively, but until further evidence is obtained they should be regarded as fitting constants. PAF spectrophotometry showed that the initial reaction of Fe(III) with S(IV) (pH 2.0) is characterized by a second-order rate constant of 4×106 M–1 s–1 which is comparable to rate of reaction of FeOH2+ with SO 4 2– . However, the PAF results should be regarded as preliminary since unexpected features in the initial data indicate that the reaction may be more complex than expected.  相似文献   
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