Cosmic Dust as an Indicator for the Genetic Classification of Granites

In the strdy of the source material of granites ,it is found that cosmic dust can be used as one of the indicators for identifying the genetic types of granites.It is suggested that granites can be grouped into two genetic types, dust-barren granite and dust-containing granite, corresponding to I-type and S-type respectively as defined by Chappell et al.

A NEW METHOD OF ANALYZING SURFACE CRACKS

The authors have developed a new line-spring boundary element method in the present paper, which combines the advantage of the line-spring model with that of the boundary element method. This method reduces the three-dimension problem of the surface cracks into a quasi-one-dimension problem and can be used to analyze the surface cracked plate under various loading conditions. In this paper theoretical analyses and numerical verifications are carried out. The calculated results are reported, which indicate that the present method is efficient and can be used to analyze the surface crack problem on a personal computer.

NUMERICAL SOLUTION OF SINGULAR PERTURBATION PROBLEMS FOR THE FOURTH-ORDER ELLIPTIC DIFFERENTIAL EQUATIONS

In this paper we construct the finite-difference scheme for the singularly perturbed boundary value problem for the fourth-order elliptic differential equation on the basis of paper [1], and prove the uniform convergence of this scheme with respect to the small parameter Ε in the discrete energy norm. Finally, we give a numerical example.

ON THE RELATIONSHIP BETWEEN THE TYPES OF SPACE GROUPS OF HIGH-TEMPERATURE PHASE AND LOW-TEMPERATURE PHASE AND THE NATURE OF DOMAIN STRUCTURE FOR PHASE TRANSITIONAL MINERAL

Recently, with the increasing use of TEM technique in mineralogy, more and more space groups of high-temperature phases and low-temperature phases and the domain structures of phase transitional minerals have been determined. Therefore, on the basis of summarizing the numerous results of individual minerals, it is necessary to discuss the relationship between the types of space groups of two phases and the nature of

BASALTIC COLUMNAR JOINTING——A PHENOMENON OF SELF-ORGANIZATION?

Basaltic columnar jointing is a protogenetic-tensile-cracking structure of basalt, which includes two tiers of polygonal (usually hexagonal) prisms with their thickness and length being different. The origin of columnar jointing had been explained by the traditional hypothesis of cooling-contraction for a long time. In 1981, the hypothesis of double-diffusive convection, which is analogous to the theory of salt fingers in marine physics, was proposed by Kantha, and 'basalt fingers'—a new concept was adopted.

Solution and Diffusion Behavior of Pure Gases and Gas Mixtures in Glassy Polymer Membranes

A general model for the solution and diffusion behavior in pure gas-polymer membrane systems and gas mixture-polymer membrane systems has been developed. Proved by experiments on different glassy and rubbery polymer membranes at various temperatures and pressures, this model can achieve the prediction of permeation behavior of pure gases and gas mixtures in polymer membranes only using the model parameters obtained from experiments on pure gases. The calculated results are in good agreement with experimental.

THE CRYSTAL AND MOLECULAR STRUCTURE OF MACROCALIN-A

I.INTRODUCTION The compound C24H30O9,named macrocalin-A, was isolated by Cheng Peiyuan et al. from Rabdosia macrocalyx （Dunn） Hava, a Chinese anticancer herb. Its structural formula was inferred by means of spectroscopic analysis as follows:

A CRYSTALLOGRAPHIC STUDY ON THE DOMAIN STRUCTURE OF P2_1ca ORTHOPYROXENE

Recently, a breakthrough has been made on the topological structure of orthopyroxene. The result shows that the space groups of all natural orthopyroxenes are P21ca, instead of the conventionally held Pbca. Moreover, P21ca orthopyroxene is formed when Pbca orthopyroxene is cooled down from a high temperature. LUO et al.

A STUDY ON THE GENESES OF SURFACIAL TEXTURES OF COSMIC DUST

Most cosmic dusts possess distinctive surfacial textures. The investigation on these textures greatly contributes to the research of ablation for meteorite and the geneses of cosmic dusts.

A METHOD FOR FITTING COMPLEX MSSBAUER SPECTRA——GAUSS-NEWTON METHOD WITH MODIFIED FACTORS

Ⅰ. INTRODUCTION Mssbauer spectroscopy is one of the important modern methods for microstructural analysis of substances. For accurate determination of the Mssbauer spectral parameters, namely, the position, intensity, and width of each absorption peak of

Domain Structures in Minerals

Domain structures in mineral crystals could be categorized into three groups and several subgroups within each group, based on characteristics of domain structures and mechanisms causing domain structures: (ⅰ) domain structures constituted by domains with the same (or identical) crystal structure and chemical composition, including anti-phase domain structures, twinning domain structures, inversion domain structures, and translationtwinning domain structures; (ⅱ) domain structures constituted by two or more than two kinds of domains with the same chemical composition but different crystal structures; and (ⅲ) domain structures constituted by two kinds of compositional and structural different domains, including exsolution-induced and polysomatic reaction-induced domain structures. Different types of domain structures may display different phenomena in their TEM images and SAED patterns, due to different crystallographic characteristics of different domain structures. The domain structures in minerals may affect physical properties, chemical composition, and thermodynamic properties of minerals, and can also indicate the evolution history of minerals.