微计算机与早期型号波长色散X射线荧光谱仪联用作为控制和数据获得系统     

B.B.JABLONSKL  O.E.LEYDEN  姜桂兰 《世界地质》1983,(2)

由于采用了微计算机,可以使早期型号的波长色散 X 射线荧光谱仪廉价地配备上计算机的能力。微计算机比小型计算机的主要优点是价格低,而主要缺点是运算速度较慢。我们已经发现 APPLEⅡPLUS 微计算机能够完成以前一台较大且贵得多的小型计算机所承担的全部任务。由于微计算机用作实验室的计算机见效快、易于维修,程序灵活,所以使它成为一种有吸引力的选择对象。基体效应校正程序 XRF-4已用于微计算机,且得到极好的效果。  相似文献   

谱模式在美国国家气象中心应用一年的统计性能     

D.G.Marks  B.W.Watkins  J.D.Stackpole  黄文杰 《气象科技》1983,(5):33-37

一、引言美国国家气象中心(NMC)于1980年8月12日开始使用谱模式,结束了舒曼(Shuman)和赫韦曼尔(Hovermale)于1968年提出的、长期以来较受重视的原始方程(PE)模式。这个新的谱模式是1980年由 Sala 提出的。本文并不涉及谱模式本身的详细情况,只对它作简单的描述。  相似文献   

Variations in Typhoon Landfalls over China   总被引：1，自引：1，他引：1  

Emily A. FOGARTY  James B. ELSNER  Thomas H. JAGGER  Kam-biu LIU  Kin-sheun LOUIE 《大气科学进展》2006,23(5):665-677

The interannual variability in typhoon landfalls over China is investigated using historical and modern records. For the purpose of substantiating and elaborating upon the claim of north to south variation in tropical cyclone activity over China, a north-to-south anti-correlation in yearly activity is confirmed in the historical cyclone records. When cyclone activity over the province of Guangdong is high （low）, it tends to be low （high） over the province of Fujian. A similar spatial variation is identified in the modern records using a factor analysis model, which delineates typhoon activity over the southern provinces of Guangdong and Hainan from the activity over the northern provinces of Fujian, Taiwan, Zhejiang, Shanghai, Jiangsu, and Shandong. A landfall index of typhoon activity representing the degree to which each year follows this pattern of activity is used to identify correlated climate variables. A useful statistical regression model that includes sea-level pressure differences between Mongolia and western China and sea-surface temperature （SST） over the northwestern Pacific Ocean during the summer explains 26% of the interannual variability of the landfall index. It is suggested that a stronger than normal north-south pressure gradient increases the surface easterly wind flow over northern China： this, coupled with lower SST over the Pacific, favors typhoons taking a more westerly track toward southern China.  相似文献   

犹他州Iron县Escalante沙漠南部Escalante山谷地裂缝的成因与范围     

William  R.  Lurid  Christopher  B.  DuRoss  赵玉军 《水文地质工程地质技术方法动态》2006,(6):1-22

犹他州地质调查局对犹他州西南部Escalante山谷内的5个地裂缝进行了勘查。2005年1月8—12日，在Escalante山谷突降一场强冬季暴风雪（可引起洪水）后，Escalant山谷内出现了地裂缝。洪水的渗透和层状冲刷（或片冲作用）扩大了地裂缝的范围。这些地裂缝长约100米（330英尺）至400米（1300公尺），而且在Beryl Junction地区中部形成了一个不连续的长9千米的裂缝带（一般向北部延伸）。在某些位置，洪水侵蚀了裂缝并形成宽3米、深2米的冲沟。据当地居民描述，在洪水泛滥期间，洪水源源不断地流入地裂缝（持续时间1天或几天），并在地裂缝上部形成旋涡。布格重力数据显示，Escalante山谷是一个沉积物充填的盆地（以下简称充填盆地），其最深位置正好位于Beryl Junetion东部。Escalante山谷也是一个农业耕作区，自20世纪20年代起开始从充填盆地含水层抽取地下水。监测结果表明，自从20世纪40年代以来，Escalante山谷的地下水位开始稳定下降。近年来，由于干旱，Escalante山谷地下水位的下降速率不断增加。Beryl Junction南部地区地下水位的下降速率最大。调查结果显示，地裂缝的物理特性类似于在其他西部地区（由地下水开采和水位下降引起）形成的裂缝。这些地裂缝长与宽的比值（长宽比）较大，且大多数地裂缝是线性结构，可以在多种地层中出现并能够延伸相当大的距离。基于流入地裂缝的洪水总量，地裂缝的深度能够延伸至更大范围（甚至达到地下水位）。沉积层（含粘土）范围内的能够产生不同裂纹特征的地裂缝（例如干缩裂缝、水压实或地表断层）的其他可能的成因是震级较大的地震（大于6．5级）。此外，对Escalante山谷地面进行的高分辨率GPS勘查结果显示，在1941年-1972年期间，Beryl Junction中部地区的地面局部下沉4英尺（1．2米），在该地区（Beryl Junction中部地区）地下水位的下降速率最大。基于现有的数据得出，Escalante山谷地裂缝形成的域合理的解释是地下水开采。地下水开采能够引起地下水位明显下降、Escalante山谷含水层细粒单元永久的压实，以及Beryl Junction附近地区的地面沉降。经推断得出，Escalante山谷内的地裂缝是Esealante山谷西部不同含水层压实的差异引起的Escalante山谷内含水层（存在水平张力）的表面下沉。为了更好地了解其他地裂缝的成因和未来可能的范围，建议进行以下研究：（1）干涉雷达法确定Escalante山谷的地面沉降；（2）对Escalante山谷进行更详细地地质和水文地质勘查，来确定其与地裂缝形成之间的关系：（3）对其他地裂缝进行勘查和（4）对山谷内水井套管和井口变形进行全面分析。  相似文献   

Nitrogen in Chinese coals     

Daishe WU Baoshan ZHENG Xiuyi TANG Mingshi WANG Jun HU Shehong LI Binbin WANG Robert B. Finkelman 《中国地球化学学报》2006,25(B08):54-54

Three hundred and six coal samples were taken from the main coal mines of twenty-six provinces, autonomous regions, and municipalities of China. The method of Kjeldahl-Gunning Analysis was used to measure the nitrogen contents in the samples. Nitrogen in coals is principally of organic nature. A weak positive correlation between coal rank and nitrogen content is inferred in the study. The distribution of nitrogen in each geological age, coal-cumulating area and province＇s coals was studied. The contents of nitrogen in Chinese coals show approximately a normal distribution, and 90% of the values range from 0.52% to 1.41%, the average nitrogen content in Chinese coals is designated as the arithmetic mean, 0.98%.  相似文献   

Is environmental antimony a potential health problem？     

John G. Farmer Joanna M. Cloy Margaret C. Graham Angus B. MacKenzie Gordon T. Cook 《中国地球化学学报》2006,25(B08):68-69

Antimony has long been recognized as a non-essential, potentially toxic element. It has recently been suggested, on the basis of measured elemental profiles in peat bogs, that natural levels of Sb in the environment have been overestimated by a factor of 10 and that anthropogenic Sb deposition from the atmosphere has closely followed that of Pb. The implication is that the health effects of environmental Sb may have been seriously underestimated. To examine these propositions, we have compared new data for Sb and Pb in dated cores from four Scottish ombrotrophic peat bogs, Carsegowan Moss, Flanders Moss, Red Moss of Balerno and Turclossie Moss, in southwest, west-central, east-central and northeast Scotland, respectively. Dried peat sections, 1 to 2 cm thick, were subjected to microwave-assisted digestion in nitric/hydrofluoric acid and subsequently analyzed for a range of elements （including Sb, Pb, and the conservative elements Sc, Ti） and Pb isotopic composition by ICP-OES and ICP-MS as appropriate. Three certified reference materials, including NIMT/UOE/FM/001 Peat, were used for quality control purposes. Radiometric dating of upper and lower sections of the cores was carried out using gamma spectrometry for ^21-Pb and accelerator mass spectrometry for ^14C, respectively Some 2000 years ago, in Roman times, both Sb and Pb were clearly elevated in Scottish peat but typically at concentrations below 0.1 mg/kg and 5 mg/kg, respectively, with an average anthropogenic Sb/Pb ratio of-0.01.  相似文献   

Clay with high fluorine and endemic fluorosis caused by indoor combustion of coal in southwestern China     

Baoshan ZHENG Daishe WU Binbin WANG Mingshi WANG Xiaojing LIU Aimin WANG Guisen XIAO Pugao LIU Robert B. Finkelman 《中国地球化学学报》2006,25(B08):79-80

Indoor coal-combustion type fluorosis is the only type of endemic disease that still lacks effective method of prevention and control. By the end of 2000, there had been 33901 thousand peoples living in the indoor coal-combustion-type fluorosis area, including 17695 thousand patients of dental fluorosis, and 1465 thousand patients with skeletal fluorosis. Guizhou is the province that suffers mostly from indoor coal-combustion-type fluorosis. 28.11% of the total population of Guizhou Province, 14489 thousand peoples, including 9910 thousand dental fluorosis patients, are living in indoor coal-combustion-type fluorosis area in Guizhou Province （NSB, 2000）. During the period of 1980-1984, the following results were proved by authors ： （1） there is no positive relationship between fluorine concentrations in foodstuff and in soils and rocks; （2） absorbed fluorine from indoor combustion formed high fluorine content foodstuffs. Fluorine emitted from combustion was acid-soluble fluorine; and （3） of the two factors that induced fluorosis,  相似文献   

The medical geology revolution     

Olle C. Selinus Robert B. Finkelman Jose A. Centeno 《中国地球化学学报》2006,25(B08):81-81

Because of the importance of geological factors on health an International Working Group on Medical Geology was established in 1998, with the primary aim of increasing awareness of this issue among scientists, medical specialists, and the general public. In 2000 a new project was established by UNESCO. The primary aim of the projects was to bring together, on a global scale, scientists working in this field in developing countries with their colleagues in other parts of the world. The International Council of Scientific Unions （ICSU） also sponsored international short courses in this subject, a cooperation involving The Geological Survey of Sweden, US Geological Survey and the US Armed Forces of Pathology. In 2006 a new association was established： International Medical Geology Association, IMGA. Regional Divisions all over the world have been established. Two text books have been published, the most recent one by Elsevier 2005： Essentials of Medical Geology which has received two prestigious international awards. A website （ http：//www.medicalgeology.org ） and regular newsletters have been published. Short courses on medical geology, have been held since 2001 in more than 30 countries. Medical geology will also be one of the ten main topics within the Year of Planet Earth declared by UN General Assembly December 22, 2005. Medical geology is also one of the five topics within the GeoUnion initiative. The international impact has been tremendous. Universities all around the world are starting courses and education in medical geology, the first centers are under construction, symposias have been held and a world wide collaboration has started between geoscientists, environmental researchers, epidemiologists, toxicologists, pathologists and other scientists.  相似文献   

Determining depleted uranium （DU） contamination in soils and salt marsh sediments in the vicinity of DU munitions testing sites in SW Scotland and NW England, UK     

Ian W. Oliver Angus B. MacKenzie Rob M. Ellam Margaret C. Graham John G. Farmer 《中国地球化学学报》2006,25(B08):96-96

In its natural state uranium has three isotopes; ^238U （99.27 atom % abundance）, ^235U （0.72%） and ^234U （0.0055%）, with the ^235U ： ^238U activity ratio having a constant value of 0.045 and the ^234U：^238U activity ratio commonly ranging 0.8-1.2 for soils and sediments （e.g. Fisenne 1996）. Uranium enrichment, the process by which the fissile isotope ^235U is concentrated for the production of nuclear fuel, generates a waste product that is depleted in both ^235U and ^234U. Depleted uranium （DU） therefore has a distinct isotopic signature that can be used to monitor contamination arising from the use of munitions containing it （i.e., DU weapons and armour）. The UK Ministry of Defense has tested such munitions at coastal locations in SW Scotland and NW England, resulting in possible contamination of the surrounding terrestrial and marine environments. We examined the U isotope distribution in surface soil （top 10 cm） and salt marsh sediment samples from these locations using alpha spectrometry to determine the extent of any DU contamination from the munitions testing programme. Despite 〉30 t of DU shells having been fired into the sea in this region there was no evidence of deviation from the natural ^234U ： ^238U activity ratio range in salt marsh samples. The ^235U ： ^238U activity ratio could not be used to assess these salt marsh samples because ^235U activities were at the limit of detection for alpha spectrometry.  相似文献   

以减少碳损失为目标的印度大城市可持续林业：以德里地区为例     

Abhineety Goel  Dr. R. B. Singh 《地球科学进展》2006,21(2):144-150

试图识别德里从大气中固碳的碳源行为以及进一步证明各种造林工程有利于控制碳损失。碳化气的释放来源于城市的各个环节，包括城市的居民生活、工业过程、电力生产和轮船及热源工厂的辐射。这里主要想证明德里的土地利用/覆盖变化通过砍伐森林来进行地铁、立交桥、建筑和其他非森林可持续的城市建设对森林和树木覆盖造成的压力。所有的这些都导致德里的微气候变化，尤其是气温的升高。造林工程可以提供大量的气候变化缓解效应。  相似文献