精密主动地震监测——系统构成与试验

本文介绍的精密主动地震监测系统以与GPS保持同步的电子系统控制的旋转质量体作为地震信号源,产生精确的、高度可重复的地震信号,这种信号经过地下介质传播到达观测点纪录,由专门的计算方法提取,观测距离可以达到150km,可以获得监视地下介质结构变化的有效信息,从而实现地下介质结构及物性的主动精确动态监测.     

沉积微相测井资料神经网络判别方法研究

不同的沉积微相可以由不同的相标志组合识别,相标志与沉积微相之间的关系可以采用神经网络通过许多基本处理单元间并行的相互作用建立。沉积微相相标志既可以由地质资料的观察、岩芯分析直接获得,也可以由测井资料间接地求得     

舟山虾塘纹藤壶的繁殖生物学研究

应用挂板试验方法,研究了舟山对虾养殖塘纹藤壶的繁殖生物学。底径为５．０～１２．０ｍｍ间的怀卵个体数量最多,怀卵率随底径的增大而升高;受精卵的卵径,随胚胎发育逐渐增大。幼体表现出随机分布的附着方式。底径增大、壳高增长和湿重增加是生长表观现象。     

清代科尔沁农耕北界的变迁

根据清代对蒙政策及其对蒙施土地垦殖的影响，结合当时科尔沁建置的时空特征，恢复了清代科尔沁土地垦殖典型时期的农耕北界，发现：清代科尔沁农耕北界具有两次显著的北跃，其中，农垦的第一次扩展是在18世纪末到20世纪初的“请旨招垦”时期，导致农耕北界从清代初期的“柳条边墙”北上至今长春-四平-昌图以及敖汉、翁牛特旗南部，哲里木盟东南部、卓索图盟大部以及昭乌达盟南部变成农牧并以逐为主的交错区，农耕的第二次发展是在清末时期，农垦推到洮儿河下游及西辽河两岸地区，此时的农耕北界北起黑龙江大庆县，经白城西、通辽北、开鲁县到林西县，今吉林省西部、辽宁省北部以及西辽河沿岸地带发展成为以农为主的农牧交错区，事实证明：清朝对蒙政策及其变化是导致科尔沁农耕北界跃变的主要驱动因子之一，是科尔沁农牧交错区形成的重要人文条件。     

南极中山锚地与普里兹湾顶地形地貌特征

本文使用中山锚地选址测绘资料及考察记录,对中山锚地现代地形地貌特征进行了分析。基于中山站附近海湾海底地形复杂多变,水深变化大的特点,将研究区域主要分为水下岸坡、海底峡谷和台地3个大的地貌单元,且对海底冲刷沟槽、水下低丘、洼地等次一级地貌类型发育进行了分析。同时指出位居台地上的中山锚地发育有裂隙带,此裂隙带横跨台地,长约3.8km,宽约80m,可能会在特定条件下,如地震、冰崩等,形成因海底斜坡失稳而向深海滑塌的地质灾害。     

23Na NMR chemical shifts and local Na coordination environments in silicate crystals,melts and glasses

In order to decipher information about the local coordination environments of Na in anhydrous silicates from ²³Na nuclear magnetic resonance spectroscopy (NMR), we have collected ²³Na magic angle spinning (MAS) NMR spectra on several sodium-bearing silicate and aluminosilicate crystals with known structures. These data, together with those from the literature, suggest that the ²³Na isotropic chemical shift correlates well with both the Na coordination and the degree of polymerization (characterized by NBO/T) of the material. The presence of a dissimilar network modifier also affects the ²³Na isotropic chemical shift. From these relations, we found that the average Na coordinations in sodium silicate and aluminosilicate liquids of a range of compositions at 1 bar are nearly constant at around 6–7. The average Na coordinations in glasses of similar compositions also vary little with Na content (degree of polymerization). However, limited data on ternary alkali silicate and aluminosilicate glasses seem to suggest that the introduction of another network-modifier, such as K or Cs, does cause variations in the average local Na coordination. Thus it appears that the average Na coordination environments in silicate glasses are more sensitive to the presence of other network-modifiers than to the variations in the topology of the silicate tetrahedral network. Further studies on silicate glasses containing mixed cations are necessary to confirm this conclusion.     

STUDY ON FLUXES OF CH4 EMISSION FROM PADDY FIELDS IN CHANGCHUN AREA

CH4 is a kind of important greenhouse gases in atmosphere. The current atmospheric concentration of CH4 is about 1.7ppmv and is increasing at almost 2％ per year. The sources of CH4 include paddies, wetland and tundra, insects, the digestive tracts of ruminants, coal mining, biomass burning, and the leakage of natural gas. The total input to the atmosphere lies in the range 300－ 550Tg per year. CH4 from paddy fields is about 10％ － 20％ of total source of atmospheric CH4 (DING, 1997). …     

基于MapBasic的等高线赋值设计与实现

等高线是地形表达常用的形式之一,它是地理信息系统基础的数据模型,而高程则是构成等高线的重要属性。本设计利用MapBasic编程语言实现了对矢量化后的无值等高线批量赋予高程值[1],有效地提高了等高线高程录入的效率和准确度。文章首先介绍了自动赋值算法的基本思想,然后,结合MapBasic关键代码,从赋值等高线的获取与排序、等高线属性的修改与赋值等方面阐述了MapInfo中实现等高线自动赋值的思路,并最终给出实验结果。