陕西关中盆地大气降水同位素研究

大气降水作为地下水的主要补给源之一,它是自然界水循环过程中的一个重要环节.查明大气降水中同位素分布特征及其影响因素,不仅有助于定性或定量地研究地下水的起源和形成等问题,更有助于揭示"三水"转化关系.根据全球大气降水同位素观测网 1985～1993 年大气降水氢氧同位素资料并结合所采集样品的分析结果对陕西关中盆地大气降水环境同位素特征、变化规律及其影响因素进行了探讨,建立了西安地区雨水线,为地下水的起源及运移研究奠定了基础.     

高纯球形-准球形亚微米晶质SiO2材料的制备与表征

以天然粉石英为基本原料,通过氢氟酸与盐酸混合酸溶蚀技术和机械强力搅拌处理,制备了高纯球形-准球形亚微米晶质SiO2材料。XRD,SEM表征结果表明,制备的高纯球形亚微米晶质SiO2材料为纯结晶SiO2相,粒子呈球形-准球形,球化-准球化率达80%～90%,粒径一般为300 nm～800 nm;其化学组成为:w(SiO2)99.90%,w(Al2O3)192×10-6,w(Fe2O3)33×10-6,w(Mg)1×10-6,w(Ca)2×10-6,w(Cl-)20×10-6。     

Impedance characteristics of carbon steel under cathodic protection

INTRODUCTIONInpraCticalengineeringapplicati0ns,thecormsionofstalundercathodicprotalioncanbecontr0llediftheproodi0np0tenhalisset2O()t03(X)mVnegativewithaspeCttothenatamlcormsi0np0tenial(MasatSugi,l976,Takehiko,l972).Theprotalnp0tentia1edinpraedcalapplicationisbedonexperienceandtheory.Tooru(l985,l986)foundthattheopbocathodicproodionpotentialcoinddedwiththepotentialwhenpolarhati0nresistancemaxndnd,s0thiscoinedencecanbeedt00btainoptbore-sultforcarbonstalundercathodicpronaion.Inthiswork,the…     

Reform of Carbonate Rock Subsurface by Crustose Lichens and Its Environmental Significance

Crustose lichens are distributed extensively in karst areas in Southern China. They can be found on the surface of carbonate rocks. Through biophysical and biochemical processes, crustose lichens reform the subsurface of carbonate rocks and in the meanwhile change their physical and chemical properties: (1) the mechanical strength decreases by 17.04° on average (up to 33.2° ); (2) the chemical solution surface area increases from 28.26% to 75.36% (lichen microholes considered only); and (3) the water-holding capacity is greatly improved. Comparative field experiments between biokarst samples underneath crustose lichens and fresh rock samples with the same composition and texture show that the corrosional rate of carbonate rocks of the former is 1.264-1.643 times higher than that of the latter. Crustose lichens are considered as an activator of the surface corrosion of carbonate rocks.     

环境水土对重要建筑材料的腐蚀作用

从建筑材料和水土中活跃成分的化学性质出发,讨论环境水土成分对重要建筑材料的腐蚀的机理及其评价的有关问题。     

地下水对混凝土的pHs分解性侵蚀判别式

针对地下水对混凝土分解性侵蚀指标pHs现行评价方法中存在水样间pHs横向没有可对比性和难以定量绘制pHs分解性侵蚀分区图等两大缺陷,推出了一个新的pHs分解性侵蚀判别式sk1,用编制的"地下水对混凝土分解性侵蚀判别式计算程序",完成了新定义的判别式sk1的计算,计算结果不但具备了水样间的每种分解性侵蚀横向对比的功能,而且还具备了定量绘制每种分解性侵蚀分区图和定量绘制3种分解性侵蚀综合评价迭加图的功能。通过实例应用,形象地印证了现行评价方法存在的缺陷及现推出的判别式、定量编绘侵蚀分区图的可行性。     

点蚀损伤下桩基式平台腿柱轴压极限承载力研究

采用圆柱体点蚀损伤模型,建立含细观尺度点蚀损伤的桩基式平台腿柱多尺度精细化数值模型,研究壁厚损伤度、点蚀损伤强度以及点蚀体积损伤强度影响平台腿柱轴压极限承载力的规律。研究结果表明,壁厚损伤度及点蚀损伤强度明显削弱平台腿柱的极限强度,且随点蚀损伤强度增大壁厚损伤度的影响加剧;点蚀体积损伤强度由于综合考虑了壁厚损伤度和点蚀损伤强度的耦合因素,相比于独立考虑后两者,其更能合理地描述点蚀损伤对平台腿柱极限强度的影响,故点蚀体积损伤强度体现了点蚀损伤的关键特征。本方法不仅适用于研究点蚀损伤构件的极限承载力,其所提出的点蚀损伤模型的构建方法,可拓展于研究受点蚀损伤的整体平台结构的极限承载力,且确定点蚀体积损伤强度为描述点蚀损伤特征的关键参数后,有望将其用于修正点蚀损伤平台腿柱的承载力设计公式。     

Ultimate Load Capacity of Offshore Pipeline with Arbitrary Shape Corrosion Defects

A set of generalized solutions are proposed for estimating ultimate load capacity of pipeline with arbitrary corrosion shapes subjected to combined internal pressure, axial force and bending moment. Isotropic and anisotropic material characteristics in longitudinal and circumferential direction of pipeline are also considered in the proposed equations. Simplified numerical method is used to solve the generalized expressions. The comparisons of numerical results based generalized solutions and full-scale experimental results are carried out. The predicted results agree reasonably well with the experiment results. Meanwhile, the effects of corrosion shapes and locations on the ultimate load capacity are studied.     

大武水源地地下水水位变化及其影响因素

介绍了淄博市大武水源地地下水的补、迳、排条件,根据地下水水位的动态特征及其变化情况,分析了地下水水位的影响因素,随后提出了开采利用地下水相关技术要求及建议：黄河水与当地地下水联合优化调度、搞好太河水库管理调度、做好地下水监测和依法做好水源地地面沉降监测管理工作。     

复配型席夫碱缓蚀剂对碳钢在海水中缓蚀性能研究

设计了由邻氧乙酸苯甲醛-4-吡啶甲酰腙席夫碱80 mg/L,邻香草醛脱氢枞胺席夫碱6 mg/L,ZnSO4 50 mg/L,Tween-80 100 mg/L四元复配缓蚀剂,通过失重法、极化曲线法和电化学交流阻抗技术,研究了该复配缓蚀剂在模拟现实使用环境中的缓蚀性能。结果表明,该复配缓蚀剂的缓蚀率受海水盐度的影响不大,但该复配缓蚀剂的缓蚀性能受海水温度和海水流速的影响较大,当温度低于50℃和流速较低、缓蚀剂浓度为临界浓度时,缓蚀剂对碳钢有很好的抑制作用,而有锈试样和间浸实验发现高浓度的复配缓蚀剂可以抑制碳钢的腐蚀。