土壤气相抽提法去除红壤中挥发性有机污染物的影响因素研究

土壤气相抽提技术(SVE)是一种安全、经济、高效的土壤治理技术,广泛应用于不饱和土壤中挥发性有机污染物的去除.本实验以我国南方典型土壤红壤(粘性较大的土壤)为实验土样,选用最常见的挥发性有机物苯作为污染物,采用一维土柱通风模拟SVE过程,研究了通风流量、土壤含水率以及间歇操作对苯污染红壤去污过程的影响.结果表明,在各土柱垂向气相中苯浓度变化趋势一致,通风初期浓度迅速降低后进入长时间的拖尾阶段,拖尾阶段初期进行间歇操作可降低能耗达到较经济的治理效果.通风流量与土壤含水率是影响净化时间和修复效果的重要因素,两者均存在最佳值.当通风流量为600 mL/min,含水率为17.2%时本实验净化时间降低为36 h,去除率为99.9%,达到了最佳的治理效果.     

COMPARATIVE STUDY OF FRESH-SALT WATER INTERFACES USING FINITE ELEMENT AND SIMPLE APPROACHES

ABSTRACT: The fresh-salt water interface in artesian aquifers has been investigated by various techniques on the basis of its analogy to the free surface in earth dams or cores of dams. Although various approximations are used, some more or less exact solutions exist. One of the simple methods, that would appeal to practical workers, was developed by the analysis of hydraulic forces. However, this method has not been checked thoroughly due to the lack of wide ranges of coverage by the more or less exact solutions. In this paper a suggested finite element method is used for the purpose of comparing with the method of hydraulic forces. The presented procedure eliminates some of the difficulties and uncertainties in current finite element procedures. Both methods proved to be in close agreement. Moreover, the hydraulic heads along the upper boundary of the artesian aquifer were found to be in close agreement with Dupuit's equation. The results of this investigation would greatly simplify the more complex management problems when the effects of discharge and/or recharge wells are added to the natural flow effects.     

从慧木碰撞谈地球安全

从慧木碰撞事件出发，根据小天体与地球相撞的史实，分析了小天体撞击地球的可能性及其效应，探讨了地球免遭个天体碰撞的可能对策。     

稀土氧化物催化还原烟气中的SO2

在实验室研究结果的基础上，建立了小型实际燃煤烟气脱硫试验装置，采用实际燃煤烟气进行了稀土氧化物催化还原烟气脱硫的试验，考察了空速、反应温度对脱硫率的影响。试验结果表明，在反应温度520～550℃、空速2800h。的条件下，脱硫率为99％，NOx的去除率为95％，SO2最高排放质量浓度为100mg／m^3，NOx最高排放质量浓度为50mg／m^3，符合GB13223-2003《火电厂大气污染物排放标准》2时段标准，与实验室的实验结果基本吻合。     

Exploring Environmentalism amidst the Clamor of Networks: A Social Network Analysis of Utah Environmental Organizations

Dwelling in a world awash in multiple environmental crises while science and social theory erode the last vestiges of the subject of humanism, it makes sense to imagine our world beyond the lens of humanism and turn to diverse methodologies in order to explore what is going on and how to promote changes that nurture ecological sustainability. In this essay we take on this task in relation to environmental communication. In what follows we explore the contours of the age after humanism, what we term the Age of the Animate Earth. In the wake of the theoretical and actual deconstruction of the subject, we offer networks as a key unit of analysis. From this perspective, we suggest social network analysis (SNA) as one viable method for doing environmental communication studies and perform this move through a SNA of Utah environmental groups.     

从废FCC催化剂和废汽车尾气净化催化剂中回收稀土的研究进展

以稀土元素(简称稀土)用量较大的废FCC催化剂和废汽车尾气净化催化剂为研究对象,分析总结了两类废催化剂中稀土的成分和回收方法。从废催化剂中回收稀土普遍采用先浸出、后分离提纯的方法。浸出普遍采用无机酸(多为盐酸),分离方法包括溶剂萃取法、化学沉淀法等,最后经焙烧得到稀土氧化物。为从废催化剂中高效回收稀土,可着重考察新浸出机制的引入、分离方式的选择、分离试剂的应用,以及浸出和分离条件的优化,从而为实现工业化回收提供技术支持。     

稀土矿区污染农田土壤治理后稀土元素的赋存形态分析

针对赣南稀土矿区受污染农田土壤,研究添加改良剂沸石治理后土壤中稀土元素的含量及形态分布特征。分别采用酸法消解和Tessier连续提取法对土壤样品(土样)中稀土元素总量及赋存形态进行提取分析,并利用电感耦和等离子质谱仪(ICP-MS)测定其中15种稀土元素含量及其形态含量。结果表明,土样中各稀土元素总量高达1 296 mg/kg,远远高于全国土壤平均总量176.8 mg/kg,稀土钇(Y)含量高达386.01 mg/kg远高于其余14种稀土元素含量,土样中轻稀土元素含量与重稀土元素含量比值为0.66远小于全国土壤中轻稀土含量与重稀土含量比值(3.78),表明该稀土矿属重稀土富钇矿型,且加入沸石不能影响土样中稀土元素的总量变化;矿区农田土壤加入沸石治理前,碳酸盐结合态、有机物结合态、铁-锰氧化物结合态、可交换态和残渣态稀土元素含量分别占总量百分比分别为51.03%、29.6%、10.39%、7.52%和1.46%,加入沸石治理后,以上5种形态的稀土元素含量占总量百分比分别为8.19%、71.54%、9.35%、4.34%和6.58%,表明沸石对矿区农田土壤中稀土元素的形态分布有很大影响,并显著钝化稀土元素在土壤中的生物活性及可迁移性。     

高压直流输电系统对埋地管道干扰及防护研究进展

为了让相关人员更好地了解高压直流干扰领域研究现状,通过对国内外相关领域研究成果的总结,介绍了高压直流输电系统接地极和线路对埋地管道干扰的产生方式,分析了高压直流干扰对埋地管道的危害类型、评价指标研究现状以及现有防护措施的类型和优缺点.在此基础上,总结了目前该领域的研究重点和难点,指出了未来高压干扰问题的发展方向,为相关研究人员和工程人员提供参考和借鉴.     

Low-temperature (NO + O2) adsorption performance of alkaline earth metal-doped C-FDU-15

To improve the removal capacity of NO + O₂ effectively, the alkaline earth metal-doped order mesoporous carbon (A-C-FDU-15(0.001) (A = Mg, Ca, Sr and Ba)) and Mg-C-FDU-15(x) (x = 0.001?0.003) samples were prepared, and their physicochemical and NO + O₂ adsorption properties were determined by means of various techniques. The results show that the sequence in (NO + O₂) adsorption performance was as follows: Mg-C-FDU-15(0.001) (93.2 mg/g) > Ca-C-FDU-15(0.001) (82.2 mg/g) > Sr-C-FDU-15(0.001) (76.1 mg/g) > Ba-C-FDU-15(0.001) (72.9 mg/g) > C-FDU-15 (67.1 mg/g). Among all of the A-C-FDU-15(0.001) samples, Mg-C-FDU-15(0.001) possessed the highest (NO + O₂) adsorption capacity (106.2 mg/g). The species of alkaline earth metals and basic sites were important factors determining the adsorption of NO + O₂ on the A-C-FDU-15(x) samples, and (NO + O₂) adsorption on the samples was mainly chemical adsorption. Combined with the results of (NO + O₂)-temperature-programmed desorption ((NO + O₂)-TPD) and in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) characterization, we deduced that there were two main pathways of (NO + O₂) adsorption: one was first the conversion of NO and O₂ to NO₂ and then part of NO₂ was converted to NO₂^? and NO₃^?; and the other was the direct oxidation of NO to NO₂^? and NO₃^?.     

基于郑州地铁下穿南水北调干渠的Peck公式反演分析

土压平衡盾构隧道下穿通水运行中的南水北调工程,在国内尚属首例。以郑州地铁城郊线土压平衡盾构隧道下穿南水北调中线干渠区间实测数据为依据,将Peck公式法运用于隧道下穿南水北调工程引起的地表沉降预测研究中,利用反演分析法,通过引入最大沉降量修正系数j和沉降槽宽度修正系数k,结合实测数据对Peck公式进行修正,得出适用于郑州地区相似工程的Peck公式,并根据现场实际情况,对不同埋深条件下地表沉降规律进行研究。结果表明:引入最大沉降量修正系数j和沉降槽宽度修正系数k对Peck公式进行改进后,能够获得较准确的地表沉降预测曲线,证明了Peck公式法在隧道下穿南水北调工程引起的地表沉降预测研究中的适用性;在其他条件均相同的情况下,随着隧道埋深的增加,地表最大沉降量逐渐减小,沉降槽宽度逐渐增大。