勘查地球化学的过去与未来的发展

勘查地球化学经过了半个多世纪的发展，其工作范围在不断扩大。另一方面，应用地球化学虽经多年发展，但它仍不能解决环境和资源方面的重大问题。全球观点、地球化学图是促使应用地球化学起巨大作用的最基本东西，否则，应用地球化学就不可能有巨大的发展，勘查地球化学应该进入应用地球化学的行列。2l世纪以来，勘查地球化学已发展到应用地球化学，从研究分散模式发展到研究分布模式，从只研究成矿后的地质过程发展到研究从地球形成开始的所有地质过程中所有元素的行为，从局部到全球，从资源到环境，从发现、开发、监控到修复，从岩石圈、土壤圈到水圈、生物圈、人类圈。这样的发展趋势必将为应用地球化学解决环境和资源的重大问题做出巨大贡献。     

Intercomparison of Boron Isotope and Concentration Measurements. Part I: Selection, Preparation and Homogeneity Tests of the Intercomparison Materials

In 1999 the Istituto di Geoscienze e Georisorse (IGG), with the support of the International Atomic Energy Agency (IAEA), undertook the collection, preparation and distribution of eight geological materials intended for a blind interlaboratory comparison of measurements of boron isotopic composition and concentration. The materials came from Italian sources and consist of three natural waters (Mediterranean seawater and two groundwaters) and five rocks and minerals (tourmaline, basalt, obsidian, limestone and clay). The solid materials were crushed, milled and mixed, in preparation for distribution. Extensive assays performed at the IGG on these materials demonstrated that their boron isotopic and chemical compositions are homogeneous.
Additional homogeneity tests were carried out on solid material fragments at the GeoForschungsZentrum Potsdam, with the specific objective of investigating the suitability of some of them for the calibration in situ of micro-analytical techniques. Two materials, B4 (tourmaline) and B6 (obsidian), proved to be isotopically homogeneous and may become excellent references for in situ microanalyses of boron isotopes.
The materials described here were used as the basis of a major laboratory intercomparison study and are now available for further distribution from either the IAEA (solid materials) or the IGG (waters).     

MagiX PRO X射线荧光光谱仪在多目标地球化学调查中的应用

X射线荧光光谱分析从20世纪80年代起就成为我国化探扫面分析最有效的手段之一[1]。进入21世纪后，新一轮目标地球化学调查工作全面展开，对分析准确度和检出限提出了更高的要求[2]，使用PHILIPS公司生产的新型MagiX PRO X射线荧光光谱仪进行多目标地球化学调查样品的多元素分析。经对5000多试样分析结果表明，该仪器可分析39个元素，其中内检合格率在96％以上的有23个元素，并首次给出Cl、Br、TI等元素的结果。     

地热资源评价的蒙特卡罗法

目前国内外评价地热资源的方法 ,均将热储参数作为定值而未考虑其随机特性。蒙特卡罗法是以热储参数的随机特征为基础建立的 ,并且通过计算可以给出结果的可信度。本文在论述蒙特卡罗法基本原理的基础上 ,结合开封市地热系统 ,分别利用蒙特卡罗法和单元热储体积法对地热资源进行了计算 ,经对比分析得出的地热资源量为 133 0 95 5×10 1 3 Kcal,相当于 1 5 476× 10 1 2 度电或 7 7381× 10 8t煤所产生的热量 ,为开封市地热资源的合理开发提供了科学依据。     

二维水流数学模型区产流、汇流问题的探讨

目前,二维水流数学模型已得到普遍应用,但模型区的产流、汇流问题考虑较少。通过南水北调中线工程总干渠左岸串流区二维水流模拟计算,针对水面区和陆面区不同情况对模型区的产流、汇流问题进行了分析研究,在二维水动力学数学模型的基础上建立了串流区水文、水力学模型,提出了处理模型区产流、汇流问题的一套行之有效的方法。     

O3浓度增加对油菜影响的诊断试验研究

利用OTC-1型农田开顶式气室对油菜进行了不同臭氧浓度200×10-9、100×10-9、50×10-9、未过滤（25×10-9～40×10-9）和过滤掉自然大气的O₃后（约为10×10-9）5个处理的长期接触试验，结果表明:目前大气本底（25×10-9～40×10-9）和50×10-9的低浓度臭氧对油菜有慢性伤害作用。臭氧浓度增加到100×10-9、200×10-9时油菜出现退绿、失水等急性伤害症状。臭氧浓度增加可导致植株矮化，株型缩小，叶片数和叶面积减少，光合速率、生物产量和经济产量下降。试验还表明，正常生长的油菜移入浓度为100×10-9、200×10-9的臭氧环境下，首先受影响的是叶肉和表皮，而此环境下的新生叶片其叶脉将首先扭曲变形。     

二氧化碳浓度增加对冬小麦生长发育影响的数值模拟

根据国内外小麦生长模拟研究成果,借鉴荷兰学者的模拟思路,从作物生长的主要生理过程人手,综合考虑气候变暖与大气中CO2浓度增加等因素对作物生长发育和产量形成的影响,修正了在一级生产水平下冬小麦生长模拟模式,使得模式能够对CO2浓度的变化做出相应的反应。经资料检验,在当前CO2浓度下,冬小麦总干重和穗干重的模拟平均相对误差小于10％,其它器官干重及叶面积指数的模拟也取得了较好的结果。运用改进后的模式模拟试验了未来气候变暖和CO2倍增对冬小麦生长发育的可能影响。     

水滴冻结实验测量降水物中的冻结核含量

文中介绍了一套新研制的均匀水滴冻结实验装置 ,实验水滴与周围环境同步冷却 ,其温度梯度很小 ,可控制降温速率 ,并能自动记录冻结事件 ,从而提高了实验的精度。用此装置对北京地区 1995年底至 1998年出现的各类降水样品进行了实验 ,由水滴冻结温度谱推算了降水的冻结核浓度 温度谱 ,并对结果进行了分析和讨论     

Aerosol concentration measurement with multiple light scattering system and laser aerosol spectrometer

The performance of two different optical concentration-measuring techniques was investigated over a concentration range starting with about 10² cm⁻³ and extending over more than four decades. Both instruments are capable of real-time counting, however due to their particular design-single particle counter and ensemble particle-measuring system—they operate in overlapping, but different concentration ranges. The upper, coincidence-free counting limit for the single particle counter used in this study was established to be in the order of 10⁴ cm⁻³. The ensemble technique was found to be functional and stable for concentrations of about 10³ cm⁻³ and limited by the onset of multiple scattering at concentrations nearby 2×10⁶ cm⁻³. Within the determined boundaries, both techniques proved to provide reliable aerosol concentration data.     

EXPERIMENTAL STUDY ON FLOW AND SEDIMENT MOVEMENT IN CAVITY CIRCULATIONS

1 INTRODUCTION Cavity channels are often found in harbor basins, waterways approaching navigation locks, trench intakes and so on. Because of the expansion of channel section, the main flow is separated from the boundary and forms a circulation flow near the cavity crest. In general, the velocity and turbulent intensity in the circulation flow are lower than that in the main flow, as a result, sediment drawn into the cavity basin is very likely to be deposited there. For instance, the de…