岫岩—海城5.6级地震前电磁前兆变化特征

岫岩－海城５．６级地震前半年内,先后出现了义县地电阻率,台安地电阻率异常变化,这些异常信息也是该次地震成功预报和重要前兆判据之一。研究认为,震前的义县、台安地电阻异常属于“场兆”,而临震前的电磁辐射信息是“源兆”。同时,电阻率的异常变化显示出向震中迁移的特点。     

西安翠华山古崩塌性滑坡体的沉积特征及其形成过程

西安翠华山风景地貌由古崩生滑坡体高速运行堆积而成,堆积体存在一些反映其运动和动力状况的沉积特征,将崩塌性滑坡体的平面堆积体划分出５个平面相带;中央相带、边缘相带、抛掷相带、气浪溅泥相带和特殊的残留相带,各带有不同的沉积特征,反映出调整运动中的崩塌式滑坡体动力过程和沉积过程在平面上分布的差异,通过研究该古积物的粒径变化、砾石组构和沉积结构、构造的差异,认为该崩塌式滑坡体在运动和沉积过程,存在前后部位     

The significance of lake sediments geochemistry in environmental reconstruction of south Hongshan Lake, northwestern Tibetan Plateau during the past 150 years

1 IntroductionPast Global Changes (PAGES) is one of the important IGBP (International Geo-Biosphere Program) core programs, of which the objectives are to obtain and interpret all kinds of palaeoclimate records, understand the history of environment and ecological change, and provide basic material and necessary test for the establishment and improvement of climate forecasting models. Because the research of climatic and environmental changes on short time scale is the key connection bet…     

Reference value of old people's hematocrit and geographical factors

1 IntroductionHematocrit is an important index of hemorheology. At present, it is difficult to achieve accuracy in clinical practice, because of the lack of a unified standard of the reference value of old people's hematocrit in China. Many researchers have measured the reference value of local old people's hematocrit[1-59]. No reports on the relationship between the reference values of old people's hematocrit and geographical factors have been found. By means of correlation and stepwise regr…     

试论科研管理工作者创新素质的培养

<正> 知识经济的形成与发展,是以创新为基本动力。江泽民同志指出“创新是一个民族进步的灵魂,是国家兴旺发达的不竭动力,一个没有创新能力的民族,难以屹立于世界先进民族之林。”根据对象不同创新可划分为技术创新和非技术创新,后者包括管理创新、组织     

近400年来北极地区和中国气温变化的对比研究

对中国和北极地区近400年来的气温变化进行了趋势分析和谱特征分析,通过对比认为,北极地区及中国基本上都有17世纪、19世纪两个寒冷期和18世纪、20世纪两个温暖期,在一定程度上说明了气候变化的全球性,但两地区气温的冷暖转化不同步。中国大部分地区(除华东、新疆、西藏区外)17、19世纪升温开始得较北极早;北极地区绝大部分站点18世纪升温较中国明显,且气温变化的区域差异较大。400aBP以来两地气温变化的周期较为一致,以130～140年、100年、80年的周期为主,说明400aBP以来气温的变化具有全球性,而且气温的变化受太阳活动的影响较大,自然因素尤其是太阳活动的影响是气候变化的主要原因。     

1961-2005年中国霾日气候特征及变化分析

利用1961-2005 年中国霾日统计资料, 对中国霾的时空气候分布特征、变化趋势进行了详细分析, 并探讨了霾变化的可能原因及其与太阳总辐射、日照时数变化的关系。结果表明: 近45 年来, 中国年和四季霾日的空间分布特征均呈现东多西少的空间分布态势, 东部地区集中在三个多发区, 分别为长江中下游、华北和华南; 季节变化, 除东北地区、青藏高原、西北西部四季霾日均很少且变化不明显外, 其余大部分地区均呈现为冬季多, 夏季少, 春秋 季居中的特点。近45 年, 全国平均年霾日数呈现明显的增加趋势, 2004 年为最高值。我国东部大部地区主要呈现增加趋势, 尤其霾多发地区, 如长江中下游、珠江流域及河南西部等 地, 霾日增加幅度大, 趋势显著, 人类活动造成的大气污染物增加及天气气候变化是这些地区霾日呈现增加趋势的可能原因, 我国西部地区和东北大部地区则以减少趋势为主。华北、长江中下游地区、华南地区霾日变化趋势与日照时数变化趋势相反, 霾的增加是造成太阳总 辐射减少的主要原因之一。东北地区、西北地区、西南地区、青藏高原霾日变化和日照时数变化均呈现不明显的减少趋势, 但由于这些地区霾日发生少, 其变化不会对日照时数和太阳总辐射变化造成很大的影响。     

300年来中国森林的变化

Based on historical documents, modern survey and statistics, as well as the result of predecessor studies, the trend and main process of forest dynamics are recognized. The forest area and forest coverage rates for each province of China from 1700 to 1949 are estimated backward by every 50 years. Linking the result with modern National Forest Inventory data, the spatial-temporal dynamics of Chinese forest in recent 300 years （AD 1700-1998） is quantitatively analyzed. The study shows that in recent 300 years, the forest area in current territory of China has declined by 0.95×10^8 hm^2 （or 9.2% of the coverage rate） in total, with a trend of decrease and recovery. Before the 1960s, there was a trend of accelerated descending. The forest area was reduced by 1.66×10^8 hm^2 （or 17% of the coverage rate） in 260 years. While after the 1960s, there has been a rapid increase. The forest area increased by 0.7×10^8 hm^2 （or 8% of the coverage rate） in 40 years. The study also shows that there is a significant spatial difference in the dynamics of forest. The amplitudes of increasing and decreasing in western China are both smaller than the ones in eastern China. During the rapid declining period from 1700 to 1949, the most serious decrease appeared in the Northeast, the Southwest and the Southeast, where the coverage rate in most provinces dropped over 20%. In Heilongjiang Province, the coverage rate dropped by 50%. In Jilin Province, it dropped by 36%. In Sichuan Province and Chongqing Municipality, it dropped by 42%. In Yunnan Province, it dropped by 35%. During the recovery period 1949-1998, the western provinces, municipality and autonomous regions, including Ningxia, Gansu, Inner Mongolia, Sichuan-Chongqing, Yunnan, Tibet, Xinjiang and Qinghai, etc, the increase rates are all below 5%, while the eastern provinces, municipality and autonomous regions （except Heilongjiang, Hubei, Jiangsu-Shanghai） have achieved an increase over 5%, among which the Guangdong-Hainan, Guangxi, Anhui, Beijing-Tianjin-H     

上通流对大陆岩石圈地幔-地壳热结构模式的潜在影响

本文以多孔介质中大尺度传热问题为基础,结合热平衡理论分析与数值计算,探讨了上通流对大陆岩石圈地幔-地壳热结构模式的潜在影响.根据大陆岩石圈中孔隙波传热概念模型的初步理论分析结果,指出了采用理论分析和数值模拟相结合的方法在研究大陆岩石圈地幔-地壳热结构模式时的重要性.理论分析方法可用来确定岩石圈尺度范围内大陆岩石圈的厚度和大陆地壳相关的边界条件,从而为地壳范围内数值模型的建立提供一些重要信息.数值模拟方法可以用来模拟地壳尺度范围内地壳的详细结构和复杂几何形状.如果地壳内的热分布是所考虑的主要因素,采用具有地壳尺度的合理数值模型可以有效减少计算机工作量.利用理论分析方法求出的岩石圈尺度范围内大陆岩石圈厚度与地幔传导热流之间关系的理论解,不仅可以用来验证模拟大陆岩石圈内传热问题所采用的数值方法, 而且可以用来初步研究大陆岩石圈内热分布的基本规律,为研究岩石圈地幔热事件中大陆岩石圈热减薄过程提供相应的边界条件.本文从理论分析的观点初步探讨了中国大陆不同构造背景下大陆岩石圈的热结构模式,其结果与从地球物理和地质资料中获得的大陆岩石圈热结构模式十分吻合.研究结果表明由大陆岩石圈中孔隙波传播所导致的上通流是影响大陆岩石圈地幔-地壳热结构模式及大陆岩石圈地幔与地壳之间物质和能量交换的可能机制之一.     

粗糙集理论进行遥感图像监督分类的样本质量评价的研究

In the supervised classification process of remotely sensed imagery, the quantity of samples is one of the important factors affecting the accuracy of the image classification as well as the keys used to evaluate the image classification. In general, the samples are acquired on the basis of prior knowledge, experience and higher resolution images. With the same size of samples and the same sampling model, several sets of training sample data can be obtained. In such sets, which set reflects perfect spectral characteristics and ensure the accuracy of the classification can be known only after the accuracy of the classification has been assessed. So, before classification, it would be a meaningful research to measure and assess the quality of samples for guiding and optimizing the consequent classification process. Then, based on the rough set, a new measuring index for the sample quality is proposed. The experiment data is the Landsat TM imagery of the Chinese Yellow River Delta on August 8th, 1999. The experiment compares the Bhattacharrya distance matrices and purity index zl and △x based on rough set theory of 5 sample data and also analyzes its effect on sample quality.