一次较成功的中期地震概率预测实例

１９８８年底依据地震活动性资料，运用ＭＹＣＩＮ不精确推理方法，提出了１９８９年及稍长时间的中国大陆中期地震趋势预测概率图，这是一次较成功的中期地震概率预测实例。     

Alluvial gold in Kalimantan, Indonesia: A colloidal origin?

Extensive placer gold deposits occur in Quaternary palaeochannels in the Ampalit and Cempaga Buang drainage basins near Kasongan, Central Kalimantan, Indonesia. Broad interfluvial Pleistocene terraces surrounding the drainages also contain significant amounts of placer gold. The “channel” and “terrace” gold deposits together cover an area in excess of 180 km².Exploration for gold at Ampalit followed traditional alluvial methods, and assumed that mechanical and gravitational factors were the principal mechanisms affecting gold accumulation and concentration. Gold was considered to be physically reworked from terraces and redeposited in the present drainage channels or underlying, laterally displaced, palaeochannels. However, a comparison of gold grains from the Ampalit drainage channel and adjacent terraces indicates that gold grains in the drainage channels are possibly of colloidal origin and not mechanically transported to their present domain.The morphology of gold grains from the Ampalit drainage is compared with grains from adjacent terraces, using scanning electron microscopy and atomic force microscopy. The latter procedure allows for nondestructive analysis to give true three dimensional surface topography down to nanometre resolution. Evidence from force microscopy supports a colloidal origin for gold aggregates.The average purity of gold produced from the Ampalit dredging operation is 970 fine (970/1000) and the majority of examined gold grains extracted from beneath the drainage channel have a purity of 998 fine. This unusually high degree of purity suggests a selective dissolution/aggregation mechanism. We propose that gold is transported downward and laterally in groundwater percolating through the terrace sands and gravels to the current drainage as a humic acid-stabilised colloid. As the pregnant groundwater migrates toward the present drainage channels, it encounters a sleep chemical gradient and the colloid aggregates. The aggregation process occurs near clay zones within palaeochannel sands and gravels beneath the present river sediments. Here the colloidal aggregates form small grains (usually <1 mm) of extremely high purity.Today, the inherently unstable gold deposits at Ampalit are in a state of both aggregation and dissolution. Identification of low energy zones, location of point bar lags in palaeo and recent drainage channels, and the extrapolation of areas of low energy are not solely valid as exploration guides for gold accumulation in this environment. Exploration methods that also recognise ground water migration and composition, and the geochemical controls of dissolution and aggregation, will improve the ability to identify ore accumulations, thus contributing to improved economics of mining these deposits.     

Determining Paleosol Topography Using Seismic Refraction

The seismic refraction reversed profiling technique has been used to investigate the topography of the last interglacial soil (paleosol S1) within the central Chinese Loess Plateau near Xifeng. The results suggest an essentially flat-lying soil at a depth which varies by only a few meters over an area of more than 10 km². In addition, the results indicate a high-velocity layer at 50-60 m depth which is thought to coincide with a layer of carbonate concretions at the base of paleosol S5. The results agree well with the local loess-paleosol stratigraphy for this area and indicate that the seismic refraction method is a rapid technique for investigating paleotopography.     

无机增强纤维Ⅰ.钛酸钾纤维

结晶质的钛酸钾纤维因其性质特殊而备受青睐，本文介绍了二钛酸钾、四钛酸钾、六钛酸钾和八钛酸钾纤维的结构、性质、用途，及国内外的研究现状．     

Spatial Accessibility to Health Care Facilities in Suhum District,Ghana

To improve geographical accessibility to health facilities in rural Ghana, it has been recommended that additional health facilities be built. Resource constraints make this recommendation infeasible. Using location-allocation models, this paper demonstrates that in the Suhum District of Ghana substantial improvements in accessibility can be achieved with better locational choices and without additional facilities. Also, additional facilities will produce little improvement in accessibility if location is not explicitly considered. The paper demonstrates the utility of location-allocation models for improving accessibility to services in the Third World.     

谐波分析中波参数的误差分析

谐波分析中由于采用离散数据的有限差分代替对函数的连续积分以及实际离散数据取样方式和数据性质的不同等原因,谐波参数或多或少存在一定的计算误差和拟合误差。本文着重讨论了离散化效应对截断频率谱参数的影响以及气象中各种常用离散数据的谐波参数误差情况和校正误差的方法。     

球面斜压大气中上传行星波与纬向平均气流的相互作用

本文指出在球面斜压大气中的行星尺度扰动与纬向平均气流相互作用中必须考虑非地转风分量对位涡度南北方向输送的作用,从而证明了球面大气中行星尺度运动的波作用守恒,并求得球面大气中的行星尺度扰动与纬向平均气流相互作用的欧拉平均运动方程组。 本义利用1979年2月的实际天气观测资料分析了北半球一次对流层阻塞形势建立与平流层爆发性增温过程的行星波与纬向平均气流的相互作用。从分析结果可以看到:由于行星波向上传播,使得在高纬度对流层中、上层出现行星波的波作用通量(也称E-P通量)辐合,使得西风气流减速,因而在高纬度对流层中、上层形成阻塞形势。并且,随着行星波的继续向上传播,使得平流层下、中层的基本气流相继减速并出现东风,因而在平流层下、中层出现爆发性增温。然而,由于高纬度对流层低层出现东风,行星波不能往上传播,在上层波的E-P通量矢量变成辐散,气流由东风又变成西风。     

Emissions control and reduction

A brief review of the information available on technological means for reducing anthropogenic emissions of greenhouse gases is provided. No assessment of economic or institutional difficulties for their implementation is attempted. A few cost figures are quoted where available, usually at the single-unit, microeconomic level, and further aggregation of the data is required to estimate global costs. Considerable additional analysis is required to do the latter, since simple summation of micro-level figures will in general not correctly yield macro level costs. It follows that no conclusions can be drawn from the information provided in this paper as to the preferred, most effective strategies for abating emission growths. The review should be viewed as providing a snap-shot picture of the data available as of today that is needed as input to an analysis of means and costs for achieving global scale reduction in emissions levels.     

北半球冬季环流异常的垂直结构特征

本文对北半球100,500,700和1000hPa四层高度距平资料,应用相关分析,EOF分解和谐波分析方法,分析了北半球冬季环流异常过程中的垂直结构特征。结果表明:第一特征向量在对流层中具有明显的相当正压性结构,并且在环流异常中占有最大权重,它和半球性的天气异常有明显关系。谐波分析表明大气环流异常的正压性主要和超长波的活动有关。     

甘孜地区古地震遗迹的初步研究

本文所指的甘孜地区是指我国四川省西北部甘孜高原西部的甘孜—马尼干戈断裂带、甘孜—理塘断裂带北段以及鲜水河断裂的北西段所展布的范围。作者于1982年对该断裂的近代构造活动性进行了调查,在调查中发现了一些古地震遗迹,现报导如下: 1.甘孜地区地震地质构造背景该区处于青藏高原的东北缘,区内发育一些近于平行和相互斜交的北西向断裂构造(图