高纬电离层中非麦克斯韦分布等离子体的非相干散射谱的模拟

使用一个修正的双麦克斯韦分布函数，通过最小均方适应技术使它与高纬电离层Ｆ区中离子的非麦克斯韦速度分布函数相适配．结果表明，使用这样的分布函数可以简化非相干散射谱的计算，并有助于简化高纬地区电离层非相干散射谱的反演．     

载炭泡塑分离富集－火焰原子吸收法测定金

用载炭泡塑从５％～３０％的王水介质中吸附富集５～１０００μｇＡｕ，经无臭灰化和王水浸提，Ａｕ的回收率大于９９％。方法用于含Ａｕ量较高的矿石分析时，效果较泡塑吸附好。用火焰原子吸收法测定含Ａｕ６．８０ｇ／ｔ的金标样，验证分离富集方法的可靠性，结果平均值为６．７２ｇ／ｔ，相对标准偏差（ｎ＝１１）为３．１％。     

Electron microprobe analysis of some minor- and accessory components in mesosiderites

Summary Analyses of chromite, ilmenite, whitlockite, farringtonite, schreibersite, and tridymite from four mesosiderite specimen were made using electron microprobe techniques. These minerals are chemically homogeneous with the exception of chromite, which exhibits slight zoning and grain to grain compositional variation in the same specimen. It can be assumed that schreibersite, troilite, and phosphates formed by solid state nucleation from -NiFe or solid state reactions between mixed metal and silicate fragments at temperatures of approximately 600–700°C during a stage of thermal metamorphism. Chromite was associated with the silicate fraction before metal and silicate fragments have mixed. It is shown that the results of this work are consistent with the theory of mesosiderite genesis evolved byPowell (1969, 1971).

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Elektronenstrahlmikroanalyse einiger Nebenbestandteile und Akzessorien in Mesosideriten

Zusammenfassung In der vorliegenden Arbeit wird über Mikrosondenanalysen von Chromit, Ilmenit, Whitlockit, Farringtonit sowie Schreibersit und Troilit in vier Mesosideriten berichtet. Mit Ausnahme von Chromit, der leichten Zonarbau und geringe Unterschiede in der Zusammensetzung in derselben Probe zeigt, sind alle Minerale homogen. Für die Bildung von Schreibersit, Troilit und den Phosphaten können Ausscheidungsreaktionen im festen Zustand aus -NiFe oder Reaktionen — ebenfalls im festen Zustand — zwischen metallischen und silikatischen Fragmenten in einem Gemenge bei Temperaturen von etwa 600–700°C während einer thermischen Metamorphose angenommen werden. Chromit war schon vor der Mischung der silikatischen und metallischen Anteile mit dem Silikat assoziiert. Die Ergebnisse stehen mit einer bereits vorliegenden Theorie über die Entwicklung der Mesosiderite vonPowell (1969, 1971) in gutem Einklang.

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With 3 Figures

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Dedicated to Professor Dr.F. Hecht on the occasion of his 70th birthday.     

Low temperature\lg f_{O_2 } - pH diagrams of sulfur isotope evolution in an equilibrium hydrothermal system

According to Sakai-Ohmoto's theory regarding the evolution of sulfur isotopes in hydrothermal systems, in conjunction of new data on chemical resaction equilibrium constants and equilibrium isotopic fractionation factors as well as on individual ion activity coefficients of aqueous sulfur species, the following lgfo₂.-pH diagrams are constructed:

1. mole fractions of aqueous sulfur species (X _i ),
2. stability fields of some minerals in the Fe-S-O system,
3. diagram depicting the oxidation-reduction-state ratio for aqueous sulfur species (R′)
4. isotopic compositions of sulfur compounds ( \(\delta S_1 ^{34} \) ).

     

Response of hydrothermal activity in different types of soil at ground surface to rainfall in permafrost region

In order to understand the hydrothermal activity mechanism of active layers to rainfall in permafrost regions caused by humidification of climate, the differences of ground surface energy balance and hydrothermal activity in different types of shallow soil with the consideration of rainfall were discussed. Based on the meteorological data in 2013 observed at Beiluhe observation station of Tibet Plateau, three types of shallow ground soil (i.e., sandy soil, sandy loam and silty clay) were selected to compare the differences in the water content and energy balance at the ground surface, dynamic processes of water and energy transport in active layers and coupling mechanism under rainfall condition in the plateau using a coupled water-vapor-heat transport model. The results show that the increase of soil particle size leads to the increase of surface net radiation and latent heat of evaporation, but the decrease of soil heat flux. The difference of surface energy balance, especially the sensible heat flux and latent heat of evaporation, are larger in the warm season but smaller in the cold season. The liquid water transport under hydraulic gradient and the water-vapor transport under thermal gradient are obvious as the particle size in soil increases. However, the water-vapor flux under thermal gradient increases but the liquid water flux under hydraulic potential gradient decreases. As a result, the water content in shallow soil decreases accordingly but it increases slightly at the depth of 25 ~75 cm. Moreover, with the increase of soil particle size, the thermal conductivity of soil, convective heat transfer under rainfall and surface evaporation increase, but the soil heat conduction flux and soil temperature gradient decrease. Thus, soil temperature in sandy soil is much higher than that of sandy loam and silty clay at the same depth. The permafrost table declines with the increase of the thickness of active layer, which is unfavourable to permafrost stability. The results can provide theoretical reference for stability prediction and protection of permafrost caused by humidification of climate.     

黔东南地区金矿遥感弱信息自动提取技术研究

笔者以TM多光谱遥感数据为数据源,利用MPH矿化弱信息定量化提取技术,在植被土被覆盖严重、地质条件复杂的黔东南地区进行金矿遥感找矿试验研究,获得了良好的效果。本文主要介绍使用MPH技术的参数和方法流程及其处理的结果。     

薄互层地区高品质地震资料采集影响因素试验研究

根据薄互层地区地质特点,以及所要达到的分辨率的要求,确定了所要保护的主频频率和施工参数。针对影响分辨率的因素,在激发时使用小药量和“钻杆扫描”的方法选择激发深度;在接收时使用中高频检波器、小组合和检波器下井接收的方法,并对它们进行逐一论证,取得了较好的效果。     

基于不规则网络下网络流算法的相位解缠方法

相位解缠作为SAR干涉测量数据处理中的一个关键步骤,受到越来越广泛的关注,出现了各种各样的算法。但现有的相位解缠算法仍无法解决高噪声问题,由此导致噪声区域的误差传递到其它区域,产生全程误差,从而影响相位解缠精度。针对这种情况,我们根据网络优化原理,提出了一种基于不规则网络下网络流算法的解缠方法,以干涉相干作为评价相位质量的标准,从含有大量噪声的干涉纹图中剔除低质量的相位,只对高质量相位进行处理,最终获取有用信息。该方法可以避免低质量区域的误差对高质量区域解缠的影响,保证高质量区域的相位解缠,从而获得较理想的解缠结果。     

首次回击具有双接地点的地闪光学和电学特征的个例分析

利用成像率为1000幅／s的数字化高速摄像系统和时间分辨率为1μs的快、慢天线闪电电场变化测量仪在广州附近观测到一次首次回击具有两个接地点的负极性地闪。两个分支到达地面的时间间隔约为30μs;在发生回击R2时,其中一个分支的直窜先导发展成为企图先导。观测发现M一分量的发光要比梯级先导强;回击间的K一变化与云中的在击穿和通道的延伸有关,但不引起云地间通道的发光。光学和电场变化的同步观测证实了直窜一梯级先导的发展速度与前一次回击的时间间隔有关,较快的先导发展速度对应于较短的回击时间间隔,较慢的发展速度对应于较长的回击时间间隔。另外,本文在资料分析的基础上,提出了产生双接地点的四种可能原因。     

广西洪涝监测研究进展及业务服务情况与展望

介绍广西局地性洪涝、流域性洪涝监测预警指标研究、广西洪涝监测系统及洪涝监测业务服务开展情况,并对GIS技术在广西洪涝监测预报评估中的应用前景进行了分析。