改性SBA-15对电厂尾气CO_2的吸附性能研究

文章以三嵌段共聚物P123为模板剂、正硅酸乙酯为硅源,水热合成了介孔分子筛SBA-15,以3-丙胺基三乙氧基硅烷(APTES)为氨基化剂,采用浸渍法将其嫁接到SBA-15孔内,形成氨基化的SBA-15用于吸附电厂尾气CO2。通过氮等温吸附-脱附、XRD、TEM等测试技术对其进行了表征,考察了改性前后SBA-15的吸附性能。结果表明:改性前后的SBA-15对电厂尾气中CO2均具有良好的吸附性能,改性的SBA-15比合成的SBA-15吸附性能要好。     

Effect of chlorine content of chlorophenols on their adsorption by mesoporous SBA-15

Studies on the effect of the chlorine content of chlorophenols (CPs) on their adsorption from aqueous solution by mesoporous SBA-15 are important in understanding the mechanisms of CP adsorption. In this study, three CPs with different degrees of chlorine content (i.e., 2-chlorophenol, 2,6-dichlorophenol and 2,4,6-trichlorophenol) were investigated. The effects of parameters such as temperature and solution pH were studied. The results showed that CP adsorption by SBA-15 increased with increasing number of chlorine substituents and depended strongly on the temperature and solution pH. Thermodynamic parameters such as Gibbs free energy change (ΔG⁰), enthalpy change (ΔH⁰) and entropy change (ΔS⁰) were also calculated. By comparison of the adsorption coefficient of CPs with varying physical-chemical properties (size, hydrophobicity and electron density), we propose that hydrophobic interactions between CPs and the SBA-15 surface, as well as electron donor-acceptor (EDA) complexes between oxygen of the siloxane surface of SBA-15 (e^--donor) and the πup-system of the CPs (e^--acceptor), were dominant adsorption mechanisms.     

利用根箱法解析甜椒根际土壤中氮的行为(英文)

为研究甜椒根际土壤中氮的行为,与既报同样的方法进行研究,即,利用15NH4+,15NO3-双标记的硝胺(NH,4>15NO3,15NH4NO3),在温室里对甜椒进行6周的根箱栽培.收割后,对土壤全氮,NO3-N,水溶性NH4-N,KCl抽出NH4-N和其各自的15N atom%进行测定.结果表明,土壤全氮从非根际到根际逐渐增加,与栽培前相比,土壤全氮在非根际中减少,却在根际中增大.土壤NO3-N浓度朝根际增加到离根际2 mm处,然后激减到根际.NO3-N的来自施给NO3-N的比例靠近根际逐渐升高,在根际达到了69%,反而,来自施给NH4-N的比例靠近根际逐渐降低,在根际将至7%左右.水溶性NH4-N和KCl抽出NH4-N浓度靠近根际逐渐降低,而且,从非根际到根际,二者匀保持3∶10的比例.KCl抽出NH4-N的来自施给NO3-N的比例靠近根际逐渐升高,但在根际仍低于3%,反而,其来自施给NH4-N的比例在非根际约为47%～55%,在根际降到41%.在整个根箱里,施用NO3-N的有機率达到62%,但其值在根际比非根圈要低.相反,施用NH4-N的有機率仅11%左右,但其值在根际比非根际要高.以上结果表明,在甜椒根际土壤中氮的无机化-有机化活性与水稻相比显著低.     

Risk assessment of conventional crop plants in analogy to transgenic plants

The risk assessment of genetically-modified plants pursuant to Annex II B of EU Directive 94/15/EC assumes that it is possible to infer the environmental impacts of a crop plant from its characteristics, so most of Annex II should also be applicable to conventional plants. To test this, we surveyed reports on the ecological impacts of the cultivation of non-transgenic crop plants with novel or improved traits and, in three cases, investigated whether Annex II B would have been adequate to indicate the effects. Such an assessment appears to be feasible only if the time frame on which it is based is short, so that long-term effects cannot be assessed. Secondly, the plant must be genetically homogenous which is not always granted, e.g. with forest-trees. Thirdly, the cultivation area must be defined. Differences in the behaviour of foreign plants between their original and cultivation habitats may be ecologically relevant and should be assessed. In the (few) cases where direct inference of the observed effects was possible from inherent traits, these effects often correlated with poor adaptation to local environmental conditions. The ecological impacts of traits that had been introduced in order to overcome poor adaptation may differ widely according to the way in which the traits are exploited. In practice, the effects of agricultural measures are more important than the effects of gene transfer and invasiveness, although the latter currently play a major role in risk assessment. In the light of these deliberations, a modification of Annex II B of EU Directive 94/15/EC is suggested.     

Global Climate Talks from Failure to Cooperation and Hope: Swedish News Framings of COP15 and COP21

The purpose of this study is to offer an analysis of how two UN Conferences of Parties, COP15 in Copenhagen 2009 and COP21 in Paris 2015, were covered and debated in Swedish newspapers. Two national and two regional newspapers were selected for the study, and a qualitative frame analysis was conducted on 309 articles. A typology of frames applicable to science-related policy and climate change debates was used and its relevance for global climate summit context was discussed. Having territory in the Arctic region, indigenous populations affected by climate change measures, and political and public sensitivity to environmental issues, the climate debate has particular significance in the Swedish case. Findings indicate a trust in the role of national and supra-national governance to address climate change problems, but also that newspapers in Sweden maintained a focus on the global aspects of the two meetings, rather than framing them as surrogate battlefields for domestic politics.     

Sensitivity of Bidens laevis L. to mutagenic compounds. Use of chromosomal aberrations as biomarkers of genotoxicity

The wetland macrophyte Bidens laevis possesses suitable cytological characteristics for genotoxicity testing. To test its sensitivity as compared to terrestrial plants species currently in use in standardized assays, Methyl Methanesulfonate (MMS), N-ethyl-N-nitrosourea (ENU) and Maleic Hydrazide (HM) were used. On the other hand, the insecticide Endosulfan (ES) - an environmentally relevant contaminant - was assayed in seeds and two-month old plants. Mitotic Index (MI), frequency of Chromosome Aberrations in Anaphase-Telophase (CAAT) and frequency of Abnormal Metaphases (AM) were analyzed. MH, MMS and ENU caused a significant decrease of the MI. MMS was aneugenic whereas MH and ENU were both aneugenic and clastogenic. ES caused a significant concentration-dependent increase of total- and aneugenic-CAAT in roots and a significant high frequency of AM at high concentrations. Because of its sensitivity to mutagenic substances, B. laevis can be regarded as a reliable and convenient species for genotoxicity assays especially if aquatic contaminants are evaluated.     

黑曲霉M1M15M19降解稻草秸秆的试验研究

分析黑曲霉M1M15M19在含不同浓度的C源、N源稻草秸秆基质上培养30 d过程中木质纤维素酶类和主要化学成分.结果表明,黑曲霉M1M15M19降解秸秆的最佳条件是低碳高氮LCHN,降解秸秆中木质素的最佳条件是高碳低氮HCLN,经过25 d降解率分别为48.2%和20.4%.秸秆降解过程中纤维素酶和半纤维素酶起到了决定性的作用,秸秆中木质素降解过程中木质素过氧化物和锰依赖过氧化物起了重要作用.     

二胺基改性有序多孔SBA-15对溶液中Cd2+离子的吸附研究

具有高度有序孔道结构的SBA-15是一种广受关注的新型吸附材料,为增加其对溶液重金属离子的吸附性能,选用水热-后期接枝的合成方法,制备出二胺基改性多孔二氧化硅2N-SBA-15,并用透射电镜、X射线衍射、氮气吸附-解吸和红外光谱等手段对其结构进行了表征.并以其为吸附剂,通过批实验的方法讨论了吸附时间、体系初始pH值、吸附剂用量和温度等因素对水溶液中Cd2+吸附的影响,同时结合Zeta电势和XPS分析对其吸附机制进行了探讨.结果表明,合成的SBA-15具有规则多孔特征,SBA-15对Cd2+的吸附受体系pH控制;未改性的SBA-15对Cd2+的吸附量较小,胺基改性可以显著增强SBA-15对Cd2+的吸附能力.在100 mL 25 mg.L-1的Cd2+溶液中,2N-SBA-15的用量在7.5～20 mg之间均能对Cd2+的吸附能力约达95%左右.2N-SBA-15对溶液中Cd2+的吸附很迅速,并在30 min内达到吸附平衡;随着体系温度从25℃增加到35℃,2N-SBA-15对溶液中Cd2+的吸附率从94.73%增加到98.22%.吸附等温线可用Langmuir模型描述,在298 K时Cd2+的最大吸附量为0.9 mmol.g-1,0.1 mol.L-1HCl溶液对Cd2+的洗脱率接近93%.结合pH、温度、Zeta电势和XPS分析结果,可以推测出2N-SBA-15对Cd2+的吸附机制是包含物理吸附、离子交换和络合反应等的复杂吸附过程.2N-SBA-15是一种对水体Cd2+具有较好吸附能力的吸附材料.     

CDN辐射骚扰测试影响因素的探究

研究影响CISPR15中辐射骚扰测试项目所用的电波暗室测试法的替代方法（CDN法）的测试因素。通过在不同的测试环境、不同的布置下对比测试,得到了不同的测试结果,从而加深了对标准布置的理解,也为实验室间比对测试提供了参考。     

条件非线性最优扰动在热带气旋调控减灾中的应用初探

为主动减小热带气旋灾害,给将来热带气旋调控的工程实践奠定理论基础。从RossHoffman对热带气旋调控减灾的研究出发,引出了作为非线性最优控制技术的四维变分天气控制版本。简要介绍了条件非线性最优扰动(CNOP)的概念,在此基础上,重点介绍了CNOP方法与四维变分方法相比改进方面的主要应用,它可以利用控制过程中的观测数据,从而在天气控制方面优于四维变分技术。进一步研究了CNOP在热带气旋控制中的另外两个应用,即对初始扰动发展为热带气旋的反演以及利用CNOP寻求产生最大垂直风切变的扰动。新的非线性最优控制技术可称为"非线性最优强迫变分(NOFV)"或"非线性最优强迫扰动(NOFP)"方法,它可以使控制尽可能接近观测。研究表明,CNOP方法在热带气旋调控减灾中大有用武之地。