Ouyang Ziyuan

A Balloon-Borne Detector for Stratospheric Cosmic Dust Detection

This paper introduces a kind of cosmic dust collecting technique anddescribes in detail the structure of the collector, the balloon-basket system and concerning experimental skill.

A Preliminary Study on Dust Grains in the Stratosphere

Collected by means of a high-altitude scientific balloon and a self-made automatic sample collector, a total of 276 dust grains were selected for the study of shape, grain size and optical property. Some of the grains were examined by X-ray diffraction and electron microprobe techniques. The stratospheric dust grains can be classified as 6 types: cosmic dusts, cosmic dusts (?), microtektite, natural pollutants, artificial pollutants and the unknown substances. The different types of dust grains have different characters and distinguishing symbols.Widespread in the space of the solar system, cosmic dusts are the initial substances of the solar system and, to some degree, have recorded a great wealth of information on the early history of the solar system. So they have become one of the important objects in the field of cosmochemistry at present time. Since the 1960’s, scholars of many countries have collected cosmic dusts both in the space near the earth (using rockets, space probes and space shuttles)and in the stratosphere (using high-altitude balloons or U-2airplanes). According to the shape (the scanning electron microimage), element composition (the energy-dispersive X-ray spectrum) and optical properties of dust grains, the substances in the stratosphere can be classified as 5 types:cosmic dusts, alumina spheroids, terrestrial artificial pollutants, terrestrial natural pollutants and unknown substances (CDPET, 1982).

ABUNDANCE PATTERNS OF TRACE ELEMENTS IN COSMIC DUSTS FROM DEEPSEA SEDIMENTS

Chemical elemental compositions of some silicate, magnetic and glassy spherules picked up from deep-sea sediments were studied with INAA. The determined dements include Os, It, Ni, Co, Fe, Cr, Au, REE, etc. The elemental correlations and their enrichment (or depletion) factors relative to type C...

A preliminary study on mineralogical and chemical compositions of some chondrites falling in China

Samples are available from 37 stony meteorites falling in China. Twenty-two chondrites are examined in terms of chemical and mineral compositions, cosmogenic nuclides, formation and exposure ages, impact effect and chondrule textures. On the basis of chemical-petrologic features these chondrites are classified asE4 (Qingzhen),H5 (Jilin, Changde, Shuangyang, Anlong, Xinyi and Yangjang),L6 (Renqiu, Junan, Heze, Rugao and Nei Monggol) andLL6 (Dongtai).E4 is characterized by high iron and sulfur, with the former occurring mainly as Feo and FeS. FromH5 throughH6 toLL6, iron and nickel decrease gradually while FeO and the ratio of Fe silicate to total iron increase gradually. indicating a general increase in the orderE-H-L-LL in the degree of oxidation at the time of formation.E4 consists mainly of enstatite and, to much less extent, free SiO2 but olivine is hardly to be found. The olivine proportions amount to 29.07, 41.98 and 51.36 percent inH5,L6 andLL6 respectively, with Fa increasing from 17 to 27 percent.Recrystallization has been noticed to different degrees inH4,H5,L6 andLL6 chondrites. The extent to which the original structure disappears and the boundaries of chondrules become indistinct decreases from type 6 through type 5 to type 4, reflecting different degrees of thermal metamorphism. Major minerals in the meteorites all exhibit signs of low to medium shock metamorphism.Specific activity, depth effect and orbit effect are also measured on some chondrites that have fallen in recent years and some new information has been obtained with respect to the orbit and source region for meteorite parent bodies in space. This results show that the environment of formation ofE group may be nearer to Mars than that ofO group.Each chemical group of chondrites has its own evolutionary history, and chondritets of different chemical groups may have originated from parent bodies of different compositions. Or owing to the differentiation caused by thermal melamorphism, various kinds of meteorites may be derived from a common parent body. From this argument it is suggested that five stages may be recognized during the formation process of chondrites.

A study on cosmogenic nuclides in the Jilin meteorite and its irradiation history

Abstract44 samples of the Jilin meteorite were analyzed by various laboratories for spallogenic, radiogenic, and trapped rare gases. A non-uniform distribution has been found for the rare gases of different origins. There have been found correlations among the spallogenic rare gases, with apparent depth effects. 43 samples were analyzed for their cosmogenic radionuclides60Co,26Al,36Cl,40K,53Mn,54Mn, and22Na. Correlations have been found between60Co and53Mn and between60Co and21Ne. The Jilin meteorite has a complex history of cosmic-ray irradiation. According to the two-stage model and the other fragments have a burying depth two stages,T1=11 m.y. andT2=0.3 m.y. The burying depth of all samples in the parent body can be obtained by the content of21Ne. Jilin meteorite No. 1 is located 20–142 cm from the surface, No. 4 ranges from 106–134 cm, and the other fragments have a burying depth between 15 and 150 cm. The equation of the reference plane for the surface of the 1-stage Jilin meteoroid is 0.24x+0.81y+0.53z+0.5=0. Use can also be made of60Co to determine the burying depth of all samples in the 2-stage Jilin meteoroid (under a geometry of 4π), and further to restore the preatmospheric form and size of the parent body. During its atmospheric passage, the Jilin had an ablation rate of ca. 30%. On the basis of the two-stage model and the concentration of21Ne and60Co in the samples, we propose a scheme to restore the relative position of all samples in the parent body. 12 sample-distribution regions can be sketched out. Also can be restored the relative position of all the samples in the parent body during the two stages.