The effect of catch crops on sulphate leaching and availability of S in the succeeding crop on sandy loam soil in Denmark

Sulphate leaching losses may reduce the long-term possibility of maintaining the S supply of crops in low input farming systems. The ability of catch crops (Italian ryegrass (Lolium multiflorum Lam), winter rape (Brassica napus L.) and fodder radish (Raphanus sativus L.)) to reduce soil sulphate concentrations in autumn and make it available to a succeeding crop was investigated in 1996–1998 on sandy loam soil in Denmark. All catch crops reduced soil sulphate concentrations in the autumn compared to bare soil. Especially, the cruciferous catch crops had the ability to deplete efficiently soil sulphate levels and thus, reduce the sulphate leaching potential. The S uptake in aboveground catch crop was 8, 22 and 36 kg S per ha for ryegrass, winter rape and fodder radish, respectively. In the following spring, sulphate levels of the autumn bare soil were low in the top 0.5 m and a peak of sulphate was found at 0.75–1 m depth. In contrast, where a fodder radish catch crop had been grown, high sulphate levels were present in the top 0.5 m, but only small amounts of sulphate were found at 0.5–1.5 m depth. In spring barley (Hordeum vulgare L.), that followed catch crops, S concentrations at heading and maturity revealed that the availability of soil S increased following winter rape and fodder radish, whereas there were indications that following ryegrass, the S availability was reduced compared to bare soil. This initial study showed that catch crops have a high potential for reducing sulphate leaching and may be used to synchronise S availability with plant demand in a crop rotation.     

福建省森林固定CO2价值评估

借鉴国内外研究成果,引入“市场逼近系数”,构造森林固定CO2效益经济结构模型,评估福建省森林固定CO2价值,为福建省森林资源的科学管理和资产评估提供了借鉴和参考。     

中国东南沿海大(中)型浅成中低温热液矿床—斑岩型矿床评价的地质准则、成矿模式及其找矿意义

本文总结中国东南沿海高钾钙碱性—双峰式火山岩带中已勘查大中型矿床成矿环境的共性：矿床所处区域构造的部位、成岩与成矿时代、矿床与岩浆成因类型、火山构造及其基底构造控矿性、矿床与爆发角砾岩、矿床与矿化类型叠加与共生、矿化与蚀变的分带往、矿床定位深度与剥蚀深度。作者认为这八点可作为找寻与评价大（中）型矿床的地质准则。通过火山地质与矿床地质统一的研究提出本区晚中生代以火山为中心地热体系的成矿模式。并就三个方面作类比：①与现代火山地热体系成矿作用类比；②以紫金山高硫型浅成低温热液矿床与世界同类型矿床作比较；③与环太平洋其他火山岩带同类型矿床模式作类比．通过建立本区的模式与类比获得进一步找矿中值得重视的一些思路．     

不锈钢壳体的冷挤压工艺及模具设计

壳体是机械中广泛使用的重要零件之一.采用冷挤压工艺可提高质量、降低成本.对不锈钢壳体成形工艺及模具设计作了详细讨论.     

Uranium enrichment by the separation-nozzle process

The Science of Nature - The development of reliable manufacturing methods for commercial separation elements, the successful operation of separative stages, and extensive tests performed on plant...     

Ecoprofit-Styria-prepare Thirteen pollution prevention case studies in the Styrian industry

The paper focuses upon the organization of a federal state-funded pollution prevention project in the Styrian industry. The project includes 13 companies from the textile, pulp and paper, machine building, wood working and printed circuit board manufacturing industries, covering most of the sectors and sizes in the Styrian industry. It started in January 1994 and will last for one year. It will demonstrate the possibilities of pollution prevention and the need for further research work. This project will make use of the methods and tools that were refined in the Austrian Prepare project. As a first step, a systematic balance of all the inputs and outputs of a company is made, after which the weak points and inefficiencies of material and energy use are identified and the options for improvements, both economical and ecological, are defined. Consequently, modifications in products and production lead to a situation with less waste and emissions. The preliminary lessons from these projects are presented: as a rule, the utilities (consumption of process materials and water, cleaning, energy, preparatory and finishing steps) are treated as black boxes and usually represent a considerable optimization potential. In these areas especially there is usually a lack of information and coordination as well as a need for a systematic and comprehensive approach. Leadership in the company and creative consultants are needed for starting lasting successful pollution prevention projects.     

气相色谱法测定汽油作业环境中MTBE含量

建立了汽油作业场所空气中MTBE的气相色谱测定方法。空气中的MTBE用注射器采集，直接进样，经大口径毛细管柱分离，氢焰离子化检测器检测，以保留时间定性，峰面积定量，并考察了MTBE与甲醇、正己烷的分离效果。     

德兴地区超大型铜、金矿床成矿控制因素及其模拟实验

在深入研究德兴地区超大型铜、金矿成矿地质背景的基础上 ,从构造地球化学方面着重研究德兴地区超大型铜、金矿床成矿的控制因素 ,并进行构造控矿模拟实验。研究结果表明 ,德兴地区超大型铜、金矿床的形成除因其处于特殊的构造位置 ,具有特殊的地质背景及成矿环境外 ,还与多种地质作用、多种控矿因素耦合作用及地质构造长期发展演化使成矿物质多次叠加富集密切相关