欧洲天气雷达网的协作计划     

G.A.克利夫特 《气象科技》1983,(4)

前言“COST-72”是欧洲在科学技术研究领域第72号合作计划的缩写。由于该计划对财政上的和科学技术资源的要求,使欧洲的任何一个国家想单独来承担是不可能的。所以欧洲的一些国家联合起来,在欧洲共同体的赞助下共同来从事这项计划。该计划由许多分计划所组成,并通过每个分计划的完成来实现关于气象仪器标准化问题的总目的。下面就该计划的一个分计划——欧洲天气雷达网的协作计划作一介绍。  相似文献   

冲击变质石英的单晶X射线研究     

谢先德  J.A.明金  赵景德 《矿物学报》1983,(2)

石英在经受中等强度的冲击后其折光率和重折射率均明显下降,波状和镶嵌块状消光极发育,并出现独特的冲击微页理,这些微页理均发生在石英晶格的一些特定方位上。因此,用X射线单晶研究方法来鉴别石英单晶颗粒形变特征是最有效的方法之一。较早用X射线对受冲击石英进行研究的有赵景德,T.E.本奇(Bunch)和F.达切尔(Dachille)等人。赵景德利用德拜-席勒技术发现采自西德雷斯(Ries)陨石坑的一颗平均折光率为1.530的受冲击  相似文献   

西德莱兹厂ELSAM声学显微镜简介     

A·THAER  郭宝罗 《地质科技情报》1983,(4)

自从显微镜发明以来,由于其工作方法有了重大改进,甚至在某个时期内曾取代了化学分析的工作和方法。在这方面的发展,目前不仅能测定微小实物的光学参数,而且能获得微小实物的电子、离子、X射线、辐射热和声束的信息,例如用在非光学“探针”上。  相似文献   

如何利用和在什么情况下不用MOS指导     

D.A.Lowry  周一鹤 《气象研究与应用》1983,(5)

近十年来,我们可以看到用模式输出统计(MOS)(见Glnhn和lowry,1972)制作的指导预报日益增加。与这一问题有关的大部份有参考价值的文献,主要讨论预报因子、相关资料的样本容量、预报检验以及其它类似的课题。如何利用这种产品帮助做好台站天气预报,可资参考的文献不多。本文试图弥补上述之不足。在什么情况下不用MOS指导是明确的。如果你不去尽力改善它,就接受MOS指导产品,那么将会导致为Snellman(1978)所详细说明的气象病态。因此,本文讨论应用MOS指导预报的若干重要规则,以及这些规则在几个气象变量,诸如降水概率(POP)、风和温度预报中的应用。  相似文献   

塞拉利昂太古宙基底中不一致的Rb—Sr和Pb—Pb全岩等时年龄的意义     

R.D.Beckinsale  N.H.Gale  R.J.Pankhurst  A.Macfarlane  M.J.Crow  J.W.Arthurs  A.F.Wilkinson  李顺智 《华北地质》1982,(1)

英国地质科学研究所一个研究队(I.G.S),通过对塞拉利昂北部的野外制图和构造研究,建立了西非克拉通太古宙地层层序,划分出一个较老的利欧尼亚(Leonian)花岗岩—绿岩区,它在利比里亚构造—变质事件结束时形成的,一个花岗岩—绿岩区之前就经受过一次构造—变质事件。在法杜古区,在具有利欧尼亚构造的花岗片麻岩中,得到在统计学上是合理的但不一致的Pb—Pb和Rb—Sr全岩等时年龄分别为2959±50百万年和2753±61百万年(误差2σ)。这些年龄是和塞拉利昂其他地区的利欧尼亚和利比里亚构造放射年龄可对比,可以认为,法杜古区的Rb—Sr全岩等时年龄已受到利比里亚事件的影响。法杜古片麻岩的Pb—Pb全岩等时年龄和一个先前测定的(经重新计算并作部分检查)取自塞拉利昂东南花岗片麻岩中的Rb—Sr全岩等时年龄为2980±80百万年,为利欧尼亚构造—变质事件提供了一个确切的年龄,约2970百万年。利欧尼亚花岗岩类的。~(87)Sr/~(86)Sr初始值和现代单阶段模式U~(238)/Pb~(204)值很难与地幔的值相区分,但并不排除这种可能性,即这些花岗岩类是来自地壳或下部地壳只经历了一个短暂时期的那些母质中。法杜古区花岗片麻岩的2753±61百万年的Rb—Sr全岩等时年龄为塞拉利昂北部的利比里亚事件提供了一个确切的年龄。在野外划分出比利欧尼亚更老的(即老于2970百万年)一套岩石,但还没有测定同位素年龄。  相似文献   

地质省在前寒武纪古地磁研究中的作用     

M.D.Cavanaugh  A.E.M.Nairn  李普 《华北地质》1982,(1)

按地质省编辑了北美和欧洲波罗的海地区14亿年前的前寒武纪岩石A类古地磁资料。目的是试图建立各个构造省的极移曲线,以便检验加拿大和费诺—萨尔马提地盾的克拉通内部完整性。根据这种见解,由于资料贫乏,对大多数省来说,不可能得出任何结论。有可能提出若干试验性的意见,供以后检验: (1)单条极移曲线满足可利用的北美24亿年前的资料。 (2)从距今22亿年到18亿年,在苏必利尔省(十南方省和怀俄明省)和邱吉尔省(十斯拉夫省和拉布多省)之间形成威尔逊环。 (3)单条极移曲线满足了怀俄明省和苏必利尔省的资料。 (4)就每个省来说,有些资料不易适合任一简单极移曲线型式。  相似文献   

铀矿物标型及其实际意义     

A.A.契尔尼科夫  李连杰 《铀矿地质》1982,(6)

对矿物标型的现代理解应包括矿物及矿物共生体的标型以及矿物种类的标型特征的概念。虽然目前已对铀矿物研究,给予了相当的注意,但有关铀矿物标型方面的专门著作,尚未见到。铀对介质的物理-化学条件变化非常敏感,而且它在地壳中分布十分分散;常常形成大量具有一定的成矿溶液参数变化范围的标型矿物。四价铀矿物在近地表的地方,大致和硫化物  相似文献   

Esterase activities in the bivalve mollusc Adamussium colbecki as a biomarker for pollution monitoring in the Antarctic marine environment     

Bonacci S  Browne MA  Dissanayake A  Hagger JA  Corsi I  Focardi S  Galloway TS 《Marine pollution bulletin》2004,49(5-6):445-455

Marine environments are continuously being threatened by a large number of xenobiotics from anthropogenic sources. Even in sparsely populated and relatively pristine areas, such as Antarctica, hazardous chemicals can pose a serious environmental problem. The main aims of the present study were to (1) validate and optimize an analytical technique utilizing a microtitre-plate photometer to ascertain background levels of esterase activities in the Antarctic bivalve Adamussium colbecki, (2) carry out in situ monitoring of esterase activities to assess any potential environmental impacts of the Italian Scientific Antarctic Base "Terra Nova Bay" on the surrounding marine area. Results showed the presence of organophosphorous-sensitive cholinesterase (ChE) and carboxylesterase (CbE) activities in the gills of A. colbecki and optimal assay conditions were comparable with those found for bivalve species from temperate areas. A higher sensitivity of ChE versus acetylthiocholine activity in A. colbecki to chlorpyrifos compared to species from temperate areas may also be inferred. The in situ study indicated no differences in the environmental quality of the three study sites located around the Italian Base.  相似文献   

Polychlorinated biphenyl and organochlorine pesticide residues in Lophius budegassa from the Mediterranean Sea (Italy)     

Storelli MM  Storelli A  Barone G  Marcotrigiano GO 《Marine pollution bulletin》2004,48(7-8):743-748

Persistent organochlorines, such as polychlorinated biphenyls, including coplanar congeners and DDT compounds, were measured in the liver of a teleost species: namely, Lophius budegassa. The mean concentrations of PCBs (1249 ng/g wet wt) were comparable with DDTs mean levels (1459 ng/g wet wt). Among DDTs the compound found at the highest concentration was p,p'-DDE representing 76% of the total DDT burden. The PCB profiles were dominated by congeners 153, 180, and 138 accounting for 49.8%, 16.0% and 13.7% of the total PCBs. The total 2,3,7,8-TCDD toxic equivalent (TEQs) of six coplanar PCBs, including mono- and non-ortho congeners, was 0.98 pg/g wet wt. The congeners with highest TEQs values were non-ortho-congeners followed by mono-ortho ones.  相似文献   

Genetic variation among age-classes of the mangrove Avicennia marina in clean and contaminated sediments     

Melville F  Burchett M  Pulkownik A 《Marine pollution bulletin》2004,49(9-10):695-703

An examination was made of the genetic variation with age in mangrove populations in two estuaries in south-east Australia, one contaminated, the other uncontaminated. Sediment nutrient and metal levels, and isozyme/allozyme complements were measured in three age-classes in four stands in each estuary, to identify site and intergenerational genetic composition, and influences of sediment contamination. Within each river, there were greater genetic distances among the age-classes than among sampling sites. A downstream gradient of genetic distance was found in the uncontaminated river, but not the contaminated one, where genetic distances seemed to reflect site-specific factors, though apparently not the present sediment metal or nutrient levels. It appears that genetic distances in the polluted river may reflect past fluctuations in pollution pressures. In both rivers, genetic distances indicate that the mangroves within one estuary form one population, with 'neighbourhood' differentiation.  相似文献