水热条件与土壤性质对农田土壤硝化作用的影响

水热条件、土壤性质和耕作管理影响了土壤的硝化作用从而影响农田氮素循环和平衡.本试验选择中国东部3个气候带上的主要农田土壤：中温带黑龙江海伦的黑土、暖温带河南封丘的潮土和中亚热带江西鹰潭的红壤,在上述3个地点的生态试验站建立土壤置换试验,对比研究不同水热条件和土壤类型对玉米单作系统中土壤硝化作用的交互影响.2006～2007年的试验结果表明,在玉米抽雄期,从海伦到鹰潭（月均温由22.3℃上升到26.8℃,月降水由100.8 mm增加到199.6 mm）,3种土壤的硝化作用强度均随着月均温和月降水的增加而下降,黑土、潮土和红壤分别下降了64.2％～67.2%、 52.1%～52.5%和41.7%～75.2%,土壤的硝化作用强度与气温（r＝－0.354,p<0.01）和降水（r＝－0.290,p<0.01）均呈极显著负相关.土壤类型也显著影响了土壤硝化细菌的数量和硝化强度,硝化细菌数和硝化强度的大小顺序为：潮土> 黑土> 红壤.土壤pH对土壤硝化强度有显著影响,其相关系数r=0.551（p<0.01）.总体上,在玉米抽雄期,区域水热状况及土壤类型、施肥均影响了土壤的硝化强度,水热×土壤类型、水热×施肥、土壤类型×施肥、水热×土壤类型×施肥等对硝化强度有着极显著的交互作用.     

空调系统中温湿度与真菌污染关系的研究

良好的空气质量对人们的健康有着重要的意义。为了了解空调系统中温湿度与真菌污染的关系．利用真菌指数的方法来对其进行评价研究。结果表明环境温湿度都与真菌的生长具有显著相关性,其相关性系数分别为：r=0．912,P〈0．05;r=0．995,P〈0．05。相对湿度的变化对真菌指数的影响要大于温度的变化,减小相对湿度有助于抑制真菌的生长。     

Anaerobic benzene biodegradation by a pure bacterial culture of Bacillus cereus under nitrate reducing conditions

A pure culture using benzene as sole carbon and energy sources was isolated by screening procedure from gasoline contaminated soil. The analysis of the 16S rDNA gene sequence, morphological and physiological characteristics showed that the isolated strain was a member of genus Bacillus cereus. The biodegradation performance of benzene by B. cereus was evaluated, and the results showed that benzene could be e ciently biodegraded when the initial benzene concentration was below 150 mg/L. The metabolites of anaerobic nitrate-dependent benzene oxidation by strain B. cereus were identified as phenol and benzoate. The results of substrate interaction between binary combinations for benzene, phenol and benzoate showed that the simultaneous presence of benzene stimulated the degradation of benzoate, whereas the addition of benzene inhibited the degradation of phenol. Benzene degradation by B. cereus was enhanced by the addition of phenol and benzoate, the enhanced e ects were more pronounced at higher concentration. To our knowledge, this is the first report that the isolated bacterial culture of B. cereus can e ciently degraded benzene under nitrate reducing conditions.     

Integrating Joint Implementation Projects for Energy Efficiency on the Built Environment with White Certificates in The Netherlands

In this paper we analyze policy interactions between two innovative climate and energy policy instruments, namely White Certificates (WhC) and Joint Implementation (JI) that target at energy efficiency improvement and reductions of Greenhouse Gas (GHG) emissions. We have selected The Netherlands and Bulgaria as a case study given that the former has a cumulated experience in energy efficiency policies and the latter for a growing potential in JI projects as a host country. Based on a method of analyzing policy interactions, we demonstrate how a possible design of such a scheme can take place and how it should function. A couple of parameters that deserve attention are a baseline definition and a conversion rate for credits. Our basic finding is that an integrated scheme is complementary and can assist substantially in achieving Dutch national United Nations Framework Convention on Climate Change (UNFCCC) Kyoto Protocol targets. Dutch electricity and gas suppliers (parties that receive energy efficiency obligations) can implement energy efficiency projects domestically and in other countries, hence reducing total abatement costs. Furthermore, such a scheme can stimulate further energy efficiency actions from other stakeholders participating in energy markets. Based on an ex-ante assessment, a carefully designed hybrid WhC and JI scheme appears to be effective in terms of targets, efficient, generating positive impacts on markets and society, while uncertain in stimulating innovation.

Supramolecular chemistry—general principles and selected examples from anion recognition and metallosupramolecular chemistry

This review gives an introduction into supramolecular chemistry describing in the first part general principles, focusing on terms like noncovalent interaction, molecular recognition, self-assembly, and supramolecular function. In the second part those will be illustrated by simple examples from our laboratories. Supramolecular chemistry is the science that bridges the gap between the world of molecules and nanotechnology. In supramolecular chemistry noncovalent interactions occur between molecular building blocks, which by molecular recognition and self-assembly form (functional) supramolecular entities. It is also termed the "chemistry of the noncovalent bond." Molecular recognition is based on geometrical complementarity based on the "key-and-lock" principle with nonshape-dependent effects, e.g., solvatization, being also highly influential. Self-assembly leads to the formation of well-defined aggregates. Hereby the overall structure of the target ensemble is controlled by the symmetry features of the certain building blocks. Finally, the aggregates can possess special properties or supramolecular functions, which are only found in the ensemble but not in the participating molecules. This review gives an introduction on supramolecular chemistry and illustrates the fundamental principles by recent examples from our group.     

相互作用矩阵在煤气净化过程风险分析中的应用

以炼焦炉的化产系统为例,使用相互矩阵方法分析化学物质相互间的影响、与外部因素的关系及可能发生事故类型,并制定对策措施.     

利用等效水力传导系数在地下水与地表水交互影响模拟中的应用

在滨海地区的环境管理工作中,地表水—地下水交互影响的重要性日益凸显。一方面在湿地系统的研究中,交互影响对地下水系统有着巨大的影响;另一方面,在河流——地下水系统中,大尺度管理模型的建立也是一个难题。因此,将等效水力传导系数的概念引入环境管理之中以解决这些问题。等效水力传导系数的推导过程是基于明渠流曼宁公式建立的,完成地表水系统与地下水系统的统一。最后,以抽水井管理为例,对该方法进行了演示。     

桂西北峰丛洼地泉水和溪流在降雨过程中的水化学动态变化特征

通过对中国科学院环江喀斯特农业生态系统观测研究站所在区域的泉水和溪流在降雨时的连续采集,发现二者的水化学特征对降雨的响应较快,但变化却不同。降雨时泉水的pH值在降雨时降低,电导率和主要离子浓度升高,SI降低,pCO2升高,而溪流的电导率和主要离子浓度降低,碳酸盐矿物饱和指数(SI)降低,水中二氧化碳分压(pCO2)降低。降雨时泉水和溪流的溶质输移速率明显增加,但没有表现出在连续降雨中因为降雨强度大输移速率就高的现象,从而推断,除了雨水的稀释作用和"土壤CO2效应"外,土壤包气带的"前水"以及土壤中可交换态离子也影响了降雨时峰丛洼地水体中溶质的运移。     

“2+26”城市一次多因素叠加重污染过程的特征分析

2018年11月23日-12月4日,京津冀及周边地区"2+26"城市出现了一次长时间、大范围、高强度的复合型大气重污染过程,为揭示区域性重污染过程中多因素的综合作用,利用气象资料、空气质量监测等多源数据以及区域污染特征雷达图,对京津冀及周边地区"2+26"城市此次重污染特征和成因进行分析.结果表明:根据PM_2.5/PM₁₀[ρ（PM_2.5）/ρ（PM₁₀）,下同]可将此次重污染过程划分为4个阶段.第一阶段（2018年11月23-26日）PM_2.5/PM₁₀在0.5~1.0内波动,"2+26"城市大气扩散条件转差,一次污染物局地积累及SO₂、NO_x、NH₃等气态污染物在高湿条件下二次转化是污染形成并发展的主要原因;第二阶段（11月27日）PM_2.5/PM₁₀突降至0.2左右,"2+26"城市北部受形成于蒙古国的沙尘影响,短时ρ（PM₁₀）快速升高（峰值为818 μg/m3）,中南部受形成于内蒙古自治区阿拉善盟的沙尘及上风向PM_2.5污染的传输影响,ρ（PM_2.5）和ρ（PM₁₀）均较高,维持日均重度污染水平（参照GB 3095-2012《环境空气质量标准》和HJ 633-2012《环境空气质量指数（AQI）技术规定（试行）》）;第三阶段（11月28日-12月2日）PM_2.5/PM₁₀由0.3逐渐升至0.8,在静稳、高湿的不利气象条件下,一次污染物积累并二次转化,第二阶段残留沙尘中的矿物质对硫酸盐起到催化作用,导致ρ（PM_2.5）快速上升,"2+26"城市大部分达日均重度及以上污染;第四阶段（12月3-4日）与第二阶段类似,PM_2.5/PM₁₀突降至0.2,"2+26"城市再次受到沙尘天气和区域传输的共同影响,因冷空气持续时间较长,污染被有效清除.研究显示,此次污染过程是气象条件、污染物一次排放和二次转化、区域传输、沙尘天气等多因素综合作用的结果.当静稳、高湿等不利气象条件或沙尘天气出现时,区域应加强对各类污染物排放的管控力度,以降低污染物的一次排放、二次转化以及沙尘和区域传输的共同影响,进而削弱污染严重程度.      

Adsorption of single and mixed haloacetonitriles on silica-based porous materials: Mechanisms and effects of porous structures

Adsorption mechanisms and the role of different porous and crystalline structures on the removal of five haloacetonitriles (HANs) over hexagonal mesoporous silica (HMS), titanium substituted mesoporous silica (Ti-HMS), rod-shaped SBA-15 and microporous zeolite NaY were investigated. In addition, the effect of pH on adsorption mechanism and selective adsorption of five HANs individually and in an equimolar mixed solution were evaluated. The results indicated that the intraparticle diffusion rate constants of the mesoporous adsorbents were higher than that of the microporous NaY. In single solute, the order of adsorption preference (highest to lowest) was mono-HANs?>?di-HANs?>?tri-HAN. However, in mixed solute, the large molecular weight of the tri-HAN and di-HANs are more easily adsorbed than the smaller molecular weight mono-HANs. Except for SBA-15, the order of adsorption capacities in mixed HANs solute was not different compared to that observed for the single HAN solute, which might be caused by the higher accessibility to the active sites due to larger pore size. The ion-dipole electrostatic interaction was likely to be the main adsorption mechanism, and was favored at high pH values due to the high negative surface charge density of the adsorbent. The molecular structure of the HANs and hydrophilic/hydrophobic nature affected the adsorption capacities and their selective adsorption from mixed solutes.