Stages of surface erosion under ion irradiation

Initial stages of surface erosion have been studied for NaCl and LiF single crystals bombarded by Ar⁺ ions with 20 keV. For irradiation with doses D=10¹⁰-10¹¹ ions/cm², exoelectron emission has been used, whereas for higher doses, we have used electron microscopy. Two stages of initial surface erosion have been identified; for small doses, there is slow development of atomic-scale roughening, which reaches its peak when areas damaged by closest incident ions start to overlap, and then, beginning with D=10¹⁶ ions/cm², there is rapid etching, deep into the crystal, followed by the emergence of secondary microscopic structure, i.e. caverns, concentric closed steps and terraces. Ion-induced surface structure of alkali halide crystals has been shown to depend strongly on the presence of foreign particles on the surface, as well as on segregation. Topography of thin carbon films and some metals have been discussed.     

泥土中微量六氯环戊二烯的气相色谱分析

采用SE 3 0为固定液进行色谱柱分离 ,用外标定量法测定泥土中的微量六氯环戊二烯 ,结果最小检知量为 0 .18× 10 - 6 ,相关系数为 0 .99992。     

浅谈采用短木桩加土工网碎石垫层处理挡墙软基

结合工程实例，对采用传统的短木桩加新兴的土工合成材料——土工网及碎石垫层构成复合基础，处理河岸挡墙软基进行探讨，该方法在软土层厚度不超过4．0m的条件下，技术可靠，施工简单，工期短，造价低。     

振动筛合金篦条磨损机理及抗磨损技术

分析了山西焦化股份有限公司振动筛合金篦条磨损情况，对合金篦条磨损机理进行了研究，提出控制磨蚀和提高材料耐磨洼的方法。     

腐蚀算法在重建一类特殊管道中的应用

针对一类特殊而不能直接对其观察的管道（如动物的血管），为了准确了解其内部特征和形态，借助计算机给出了一种用腐蚀算法来重建管道原形的方法。这种方法简单易行，而且精确度高。     

硫氰酸钠湿纺腈纶设备的孔蚀与防护

本文重点讨论了硫氰酸钠湿纺腈纶设备因钝化膜缺陷和Cl-侵入而产生孔蚀的机理及环境因素对孔蚀的影响,并针对产生孔蚀的主要原因提出了防护措施。     

The current and residual value of superphosphate for lupins grown in rotation with oats and wheat on a deep sandy soil

In a field experiment on a deep pale-yellow sand in a 600 mm per annum rainfall Mediterranean environment of south-western Australia, six levels of phosphorus (P) as superphosphate (O up to 546 kg P ha^–1) were applied once only, to the soil surface, before sowing lupins (Lupinus angustifolius). The lupins were grown in a continuous arable cropping rotation with, in successive years, oats (Avena sativa), wheat (Triticum aestivum), lupins. Five such rotations were started in the experiment from 1985 to 1989. The experiment continued until the end of 1990.The relationship between lupin seed (grain) yields and the level of P applied was measured in the year of P application for five successive years (1985 to 1989). The relationship had the same general form but it varied between years, largely due to different maximum yields (yield plateaux) in each year.The residual value of superphosphate applied three years previously was measured for lupins on two occasions (1988 and 1989) relative to superphosphate applied in the current year. The residual values was different in the two years. The superphosphate applied three years previously was about 30% as effective as freshly applied superphosphate in 1988, and 12% as effective in 1989.At each harvest, the relationship between grain yield and the P concentration in the grain differed for different species. However, for each species at each harvest, the relationship was similar regardless of when the P was applied in the previous years. Thus each species had the same internal efficiency of P use curve, and yields varied only with P concentration in tissue.Bicarbonate-extractable soil P was determined on soil samples taken in mid-July of 1989 and 1990. These soil test values were related to grain yields at harvest. The relationship between yield and soil test values had the same general form but varied for different species within years and for each species between years. It also varied for each species within years depending on the year the P was applied.     

利用短周期地脉动推断深层地基S波速度

从二维随机波场的相关理论出发，提出了如何从短周期地脉动（频率＞０．５Ｈｚ）时域信号中计算Ｒａｙｌｅｉｇｈ波弥散曲线，进而反演深层地基剪切波（Ｓ波）速度的理论方法和分析技术，并结合实测信号的分析结果，探讨了该方法的可行性和实用性。     

高速公路建设水土流失防治研究

本文以西南地区的几条高速公路为例,阐述了高速公路建设项目水土流失的特点及防治对策,将工程措施与植物措施相结合并积极地采用新方法、新技术,从而有效地改善公路沿线的生态环境.     

基于WebGIS的粗泥沙集中来源区电子地图系统研究

基于WebGIS的粗泥沙集中来源区电子地图系统建设，以粗泥沙集中来源区作为研究区域，以黄河中游粗泥沙集中来源区水土保持工作流程（包括规划设计、计划管理、综合治理、预防监督和淤地坝管理等）为主线，依托黄河流域水土保持生态与环境监测系统网络、黄河流域水土保持监测系统数据库，建立覆盖黄河流域、黄土高原区、多沙粗沙区、粗泥沙集中来源区，面向不同水土保持管理层的水土保持监测与管理信息系统。