土地利用规划与旅游规划协调研究

就土地利用规划和旅游规划之间难以衔接与协调的问题,依据规划及社会经济发展的基本原则,从"两规"的差异性、"两规"协调的理论和法律依据、"两规"协调的途径三个方面,试图分析和解决这一长期困扰土地利用规划界与旅游规划界的难题.     

冻融循环对黏质粗粒土抗剪强度影响的试验研究

通过室内循环冻融循环试验和三轴不固结不排水(UU)压缩试验研究了循环冻融作用与细砾组含量(P_(2-5))对黏质粗粒土抗剪性能的影响。结果表明,冻融循环作用对黏质粗颗粒土的应力—应变曲线性状具有一定的影响,可使其由未冻融的应变软化向应变硬化转变的趋势,但随着细砾组P_(2-5)含量的增加,冻融作用对其影响逐渐减弱。随着冻融循环次数的增加,土样剪切强度呈现逐渐衰减,且在5～9次冻融循环次数后基本保持不变,多次循环冻融作用后剪切强度最大衰减幅度可达40%。弹性模量随冻融循环次数的增加上下波动较大但整体呈现下降趋势。在抗剪强度指标方面,冻融作用对黏聚力影响比较显著,随着冻融循环次数的增加,黏聚力逐渐减小,最大衰减幅度可达65%,而内摩擦角上下波动较大无明显趋势。此外,随着细砾组P_(2-5)含量的增加,剪切强度、弹性模量及抗剪强度指标均呈现不同程度的减小,这与粗粒土内部粗颗粒和细颗粒占比及其强度发挥机制有关。     

西安市高新技术产业开发区向生态工业园区的转变经验

生态工业园是继经济技术开发区和高新技术开发区后的第三代工业园区,是实施循环经济的三个领域之一。本文介绍了西安市高新技术产业开发区向生态工业园区转变模式与实施步骤,并总结实践经验。     

Enhanced dewatering characteristics of waste activated sludge with Fenton pretreatment: effectiveness and statistical optimization

In this work, the enhanced dewaterabing characteristics of waste activated sludge using Fenton pretreatment was investigated in terms of effectiveness and statistical optimization. Response surface method （RSM） and central composite design （CCD） were applied to evaluate and optimize the effectiveness of important operational parameters, i.e., H202 concentrations, Fe2＋ concentrations and initial pH values. A significant quadratic polynomial model was obtained （R2= 0.9189） with capillary suction time （CST） reduction efficiency as the response. Numerical optimization based on desirability function was carried out. The optimum values for H202, Fe2, and initial pH were found to be 178 mg-g-1 VSS （volatile suspended solids）, 211mg.gI VSS and 3.8, respectively, at which CST reduction efficiency of 98.25% could be achieved. This complied well with those predicted by the established polynomial model. The results indicate that Fenton pretreatment is an effective technique for advanced waste activated sludge dewatering. The enhancement of sludge dewaterability by Fenton＇s reagent lies in the migration of sludge bound water due to the disintegration of sludge flocs and microbial cells lysis.     

植被在大气汞收支中作用的研究进展与展望

在汞的生物地球化学循环中,对于"源"和"汇"的认识还存在许多不确定性。大气汞收支不平衡的问题使得植被在汞循环中的作用日益凸现;开展植被在大气汞收支中作用的研究有助于为全球汞减排政策的制定提供参考。本文首先概述了植被中汞的来源和影响因素及其与大气汞的源汇关系;进而重点论述了植被参与大气汞收支的主要方式:凋落物沉降、生物质燃烧和植被表面与大气汞的动态交换,并阐述了植被在大气汞污染监测中的应用;最后在总结我国相关研究的基础上展望了未来的发展方向。     

自噬抑制剂3-甲基腺嘌呤在纳米氧化铝致斑马鱼幼鱼早期神经毒性中的作用

由于纳米氧化铝(alumina nanoparticles,AlNPs)独特的理化性质,被广泛应用于医药、电子和化妆品等多个领域,但关于AlNPs的早期神经毒性效应及其潜在机制尚未完全阐明.为探讨AlNPs的毒作用机制,以及自噬抑制剂3-甲基腺嘌呤(3-methyladenine,3MA)对AlNPs致斑马鱼幼鱼早期神经毒性的影响,将6 hpf(hours post-fertilization)的斑马鱼胚胎分为对照组、3MA组、AlNPs组和AlNPs+3MA组.观察胚胎和幼鱼的形态学变化以及幼鱼的一般毒性,并检测神经行为改变、氧化应激水平以及幼鱼体内自噬相关基因beclin1、lc3Ⅱ和vps34的表达情况.结果表明,各组幼鱼在死亡率、孵化率和畸形率方面无显著性差异.形态学观察结果显示,AlNPs组受精卵在12 hpf和24 hpf出现发育迟缓,加入3MA后,在24 hpf后受精卵发育好转.运动行为检测发现,AlNPs组幼鱼黑暗状态下的平均速度、移动距离和趋触性程度显著降低(P<0.05).在强光刺激下的惊恐逃避反射实验中,AlNPs组幼鱼在光照时的速度显著降低(P<0.05).氧化应激水平检测结果显示,AlNPs组超氧化物歧化酶(superoxide dismutase,SOD)活性显著降低(P<0.05),而AlNPs组乳酸脱氢酶(lactate dehydrogenase,LDH)活性显著升高(P<0.05).自噬相关基因beclin1、lc3Ⅱ和vps34在AlNPs组表达均显著升高,加入3MA后,基因表达降低,并具有统计学意义(P<0.05).上述结果表明,AlNPs诱导过度自噬的发生造成斑马鱼幼鱼早期神经毒性,而3MA可以减轻AlNPs引起的氧化损伤并下调自噬相关基因的表达,明显改善AlNPs暴露所致的早期神经毒性.     

Simultaneous removal of NOx and chlorobenzene on V2O5/TiO2 granular catalyst: Kinetic study and performance prediction

• A V₂O₅/TiO₂ granular catalyst for simultaneous removal of NO and chlorobenzene. • Catalyst synthesized by vanadyl acetylacetonate showed good activity and stability. • The kinetic model was established and the synergetic activity was predicted. • Both chlorobenzene oxidation and SCR of NO follow pseudo-first-order kinetics. • The work is of much value to design of multi-pollutants emission control system. The synergetic abatement of multi-pollutants is one of the development trends of flue gas pollution control technology, which is still in the initial stage and facing many challenges. We developed a V₂O₅/TiO₂ granular catalyst and established the kinetic model for the simultaneous removal of NO and chlorobenzene (i.e., an important precursor of dioxins). The granular catalyst synthesized using vanadyl acetylacetonate precursor showed good synergistic catalytic performance and stability. Although the SCR reaction of NO and the oxidation reaction of chlorobenzene mutually inhibited, the reaction order of each reaction was not considerably affected, and the pseudo-first-order reaction kinetics was still followed. The performance prediction of this work is of much value to the understanding and reasonable design of a catalytic system for multi-pollutants (i.e., NO and dioxins) emission control.     

基于隐患整改的职业安全管理

1引言 安全的本质是系统存在的正常状态,是系统不发生意外、运行正常、进展顺利的动态过程.在此过程中,系统不对人身构成危害、不对设备造成损坏、不使系统有目的的行动暂时或永久终止.     

Evaluation and remediation of organics,nutrients and heavy metals in landfill leachate – a case study in Beijing

Leachate pollution in landfill sites is a major source of environmental concern. This study evaluates organics, nutrients and heavy metals in a landfill site in Beijing, and introduces a method combining coagulation–flocculation with filtration for the advanced treatment of leachate. The results confirm that COD_Cr, TN, NH₄⁺ ? N, TP, Mn and As in leachate treated by an anaeobic–oxic biological method are unable to meet discharge or surface water quality standards. When treated with coagulation–flocculation combined with filtration under optimal conditions (cationic polyacrylamide dosage of 8.0 mg/L; polyaluminium chloride dosage of 350 mg/L; 0.4–0.6 mm ceramsite media in the filtration process), the residual NH₄⁺? N, TN, Mn and As in the leachate meet the maximum allowed values for landfill leachate discharge or surface water quality standards in China; the exceptions are chemical oxygen demand and total phosphorus. Leachate treatment processes could be further strengthened or improved.     

一株氯苯优势降解菌的降解条件优化

以氯苯降解率为降解效果指标,以降解温度、初始pH、降解时间、接种量和氯苯初始浓度为影响因素,对实验室保藏的一株氯苯优势降解菌株Lysinibacillus fusiformis LW13降解氯苯的降解条件进行优化。单因素试验结果表明,该降解菌株对氯苯的适宜降解条件分别为:温度20～40℃,pH为8.0,降解时间4 d,接种量2%～4%,氯苯初始浓度60～140 mg/L。以降解温度、氯苯初始浓度和接种量这三个显著影响因素进行正交试验,结果表明各影响因素的主次顺序为降解温度>氯苯初始浓度>接种量,最佳降解条件为降解温度35℃、氯苯初始浓度100 mg/L和接种量4%,最佳降解条件下氯苯降解率可高达93.8%。