基于CLUE-S和灰色线性规划的嘉兴北部土地利用优化配置研究

构建基于CLUE-S与灰色线性规划混合模型的土地利用优化配置方法,在导入区域政策、社会经济、生态目标和土地利用现状等条件下,进行土地利用数量结构与空间布局的统一优化,并以嘉兴北部地区为例进行实证研究,共设置现状趋势情景、规划目标情景和规划可持续情景这3种模拟情景.规划可持续情景侧重社会经济环境效益,故对建设用地快速增长和农用地持续减少起到明显调控作用,可实现生态敏感区环境和粮食安全的双重保护,是理想的土地利用优化方案.CLUE-S模型与灰色线性规划的耦合能够兼顾现状条件和区域发展目标,模拟土地利用的数量和空间变化,是解决土地资源优化配置问题的有效方法.     

Characteristics of geological hazards in South China coastal areas and impact on regional sustainable development

Prevention and treatment of geological hazards is important for the sustainable development of human society. Surface geological hazards alone caused direct economic losses of ¥3.47 billion, with 768 deaths and 785 injuries in Guangdong Province, South China, from 1994 to 2005. The major factors causing geological hazards can be categorised into three types: geo-environmental, climatic-meteorological and human activity. Accompanied by rapid economic development and population growth, human activities can cause geological hazards that are as serious as those caused by natural factors. The authors propose some suggestions for prevention and treatment of geological hazards to achieve sustainable development on the Chinese coast.     

Enhanced production of laccase by Coriolus hirsutus using molasses distillery wastewater

The effect of physical parameters of cultivation (load volume, temperature, pH, agitation, inoculum size, and incubation period) in the production of laccase by wood-rotting basidiomycete Coriolus hirsutus were studied using diluted molasses distillery wastewater (MDW) as a major composition. Using fractional factorial design, our study first identified load volume, agitation, and inoculum size as statistically significant factors. Optimal preferences and mutual interactions of the factors were then determined by the response surface method, which is based on the center composite design. A quadratic model was used to fit the experimental data. The optimized operational parameters for laccase production were determined to be the following: culture temperature of 25°C, pH 4, load volume of 40 mL diluted MDW in 150 mL flask, agitation rate of 183 r·min^?1, inoculation of 11.5% v/v, and cultivation time of 6 d. The experimental validation under these conditions (the maximum laccase production of 2198.2 U·mL^?1 was within the confidence interval) subsequently verified the accuracy of the constructed model. Moreover, the removal of chemical oxygen demand and nitrogen of MDW reached 62.85% and 48.00% respectively, and the decolorization ratio under the optimal condition was 41.85%. The enhanced production of laccase by C. hirsutus is a new recovery strategy for MDW.     

Visual MODFLOW在露天矿地下水模拟中的应用

用Visual MODFLOW建立了某露天矿地下水数值模型,运用其跟踪模拟(MODPATH)子模块及溶质运移模拟(MT3D)子模块对该露天矿地下水的水质点示踪和三维污染羽进行了模拟,模拟结果有助于识别该矿露天开采对地下水污染的污染源及污染途径,为预测露天矿开采期间地下水位及水质的变化,采用的监测与预保护措施提供了决策依据。     

Fenton试剂氧化降解紫丁香醇的研究

在自制的圆柱型双层玻璃反应器中,以木素类模型物紫丁香醇(SL)为目标化合物,考察Fenton试剂对紫丁香醇的降解效果,研究溶液的pH值、H2O2的用量、Fe2+的用量、紫丁香醇溶液初始浓度、反应时间、紫外光照射等因素对紫丁香醇降解的影响。实验结果表明:在室温条件下,当体系pH值为3.0时,加入两倍理论用量的H2O2,Fe2+与H2 O2的物质的量之比为1︰50,反应60 min后,50 mg/L的紫丁香醇的去除率可达87.5%;当体系中引入紫外光后,Fenton试剂的氧化性明显增加,反应速度显著加快,30 min后紫丁香醇可完全矿化。     

Urea formation from carbon dioxide and ammonia at atmospheric pressure

Urea synthesis, currently the largest use of carbon dioxide in organic synthesis, is conventionally operated at high pressure and high temperature. Here, we report for the first time that urea forms at atmosphere and ambient temperatures by negative corona discharge in gas phase. The conversion of CO₂ and yields of a solid mixture of urea and ammonium carbamate, which was identified by the ¹³C NMR spectrum, rise with reducing temperatures and increasing molar ratios of NH₃/CO₂ and discharge frequencies. The conversion of carbon dioxide was found to be 82.16?% at 20?°C and 1?atm with a molar flow ratio of n(NH₃)/n(CO₂) of 2.5. High pressure and high temperature as energy inputs are not necessary.     

RBCA、CLEA及CalTOX模型在苯并[a]芘污染场地健康风险评估中的应用比较

为探讨不同模型对污染场地健康风险评估结果的影响,以苯并[a]芘为例,采用RBCA、CLEA和CalTOX模型对某工业污染场地表层土壤进行健康风险评估,分析了评估结果的差异和原因,同时对模型的主要暴露参数进行了敏感性分析,并推导出基于风险概率分布的土壤修复限值。结果表明,RBCA、CLEA和CalTOX模型计算的苯并[a]芘致癌总风险分别为2.40×10-4、6.32×10-4和7.04×10-6,且经口摄入和皮肤接触2个途径对人体健康造成的危害最大。降解作用是影响CalTOX模型风险评估结果不同于RBCA和CLEA模型的重要因素,3个模型间参数取值及方法学的差异也会导致风险评估结果不同。各模型暴露参数的敏感性排序也有差异。采用基于风险概率分布的方法推导土壤修复限值,RBCA、CLEA和CalTOX模型所得结果分别为0.18、0.08、0.13(不考虑降解作用CalTOX模型)和10.74(考虑降解作用CalTOX模型)mg·kg-1,为各模型直接推导值的1.5～2.6倍。基于风险概率分布的方法可有效降低风险评估过程中参数不确定性的影响,为工业污染场地土壤修复值的制定提供参考。     

冷藏技术对发光细菌活性及毒性测试性能的影响

由于发光细菌的在线毒性监测技术受到了细菌生物活性稳定性保持问题的制约,探索一种脱脂牛奶菌悬液冷藏复苏方法,以提高发光细菌活性的保持时间。比较了明亮发光杆菌新鲜菌液冷藏、冻干粉菌悬液冷藏和脱脂牛奶菌悬液冷藏对发光细菌生物活性的影响,同时,比较了不同渗透压调节液对菌悬液急性毒性测试的灵敏度和稳定性的影响。结果表明,质量分数为25%的脱脂牛奶可提高发光细菌生物活性的稳定性,菌悬液冷藏7d后复苏,相对发光率仍可达92%。2%NaCl和10%蔗糖为渗透压调节液时,冷藏至第7天的发光细菌脱脂牛奶菌悬液对重金属毒性测试的灵敏度,与新鲜菌液基本相同,但添加蔗糖降低了其对有机物的测试灵敏度。利用发光细菌脱脂牛奶冷藏菌悬液对Zn~(2+)进行连续7d的毒性测试,EC_(50)的变异系数小于15%,结果稳定性良好。     

Reduction of hexavalent chromium with scrap iron in a fixed bed reactor

The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time (EBCT), and initial Cr(VI) concentration on Cr(VI) reduction were studied. The results showed that the pH, EBCT, and initial Cr(VI) concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57 mg Cr(VI)·g^-1 Fe⁰ at pH 3, 5, and 7 (initial Cr(VI) concentration 4 mg·L^-1, EBCT 2 min, and temperature 25°C), 0.51, 1.51, and 2.85 mg Cr(VI)·g^-1 Fe⁰ at EBCTs of 0.5, 2.0, and 6.0 min (initial Cr(VI) concentration 4 mg·L^-1, pH 5, and temperature 25°C), and 2.99, 1.51, and 1.01 mg Cr(VI)·g^-1 Fe⁰ at influent concentrations of 1, 4, and 8 mg·L^-1 (EBCT 2 min, pH 5, and temperature 25°C), respectively. Fe(total) concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr(VI) ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr⁶⁺·g^-1 Fe. Scanning electron microscope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron.     

桂林岩溶表层带土壤CO2体积分数时空变化规律及其意义

通过2010—2011年的监测建立了桂林盘龙洞坡地和洼地不同深度土壤CO2体积分数的季节性变化。监测土壤CO2体积分数空间上变化为:坡地80 cm>50 cm>30 cm;洼地80 cm>100 cm>50 cm>30 cm。监测土壤CO2体积分数时间上变化为2010年7月和2011年6月未CO2体积分数达到最高值,2010到2011年冬季为土壤CO2达到最低值。由于受到大气降水量急剧减少的影响2011年土壤CO2体积分数整体比2010年低。显示大气降水量也是影响土壤CO2体积分数的重要环境因素。为我国固碳减排科学的选择时间和空间提供有力的依据。