亚热带河口陆基养殖塘底泥甲烷产生动力学研究

河口区陆基围垦养殖塘是重要的温室气体排放源,但其底泥甲烷产生动力学特征目前尚未厘清.本研究对我国东南沿海亚热带闽江河口、木兰溪河口和九龙江河口的6个南美白对虾（Penaeus vannamei）养殖塘底泥进行了为期60 d的室内厌氧培养,并对甲烷累积产量曲线利用一阶动力学模型及改进的岡珀茨模型进行拟合和分析.结果表明,所有河口陆基养殖塘底泥产甲烷过程是一个动态变化过程,可分为延滞、产生和稳定3个阶段.延滞期发生在培养初期1~4 d,产生期主要集中在4~25 d,在培养25 d后,所有养殖塘底泥的甲烷累积产量曲线趋于平衡.盐度和孔隙水DOC浓度均能够影响养殖塘底泥甲烷产生动力学拟合参数.随着养殖塘底泥盐度的增加,甲烷最大产生潜力由5961 ng·g^-1减少至559 ng·g^-1,甲烷最大产生速率由674 ng·g^-1·d^-1减少至84 ng·g^-1·d^-1.研究表明,一阶动力学模型更适合低盐养殖塘底泥甲烷产生动力学过程的拟合,而改进的岡珀茨模型更适合高盐养殖塘底泥甲烷产生动力学过程的拟合.选择近海养殖塘进行南美白对虾养殖及在甲烷产生期来临之前清除底泥可极大程度地减少养殖塘底泥温室气体CH₄的产生潜力.     

改性生物炭对水体中头孢噻肟的吸附机制

采用液相浸渍方法制备3种改性生物炭,采用红外光谱、扫描电镜、比表面积测定仪和元素分析仪等手段表征生物炭表面结构形貌和组成.以头孢噻肟为探针分子,考察改性生物炭对头孢噻肟的吸附性能及吸附影响因素,并探究其吸附机理.结果表明,30min时碱改性生物炭（BC-NaOH）对头孢噻肟的吸附率为83%,符合伪二级动力学方程（R²>0.99）,吸附率显著大于其他几种材料.热力学研究表明,BC-NaOH吸附头孢噻肟是自发放热过程.基于反应热力学及吸附率影响因素分析,得出BC-NaOH吸附头孢噻肟的机理是疏水亲和作用和静电引力.     

秸秆露天焚烧典型大气污染物排放因子

利用烟气污染物稀释采样系统,基于实际测试,针对玉米、小麦、花生和棉花4种农作物秸秆开展露天焚烧排放大气污染物采集和分析.利用修正燃烧效率区分燃烧状态,根据碳平衡法计算烟气中颗粒物和气态污染物排放因子.结果表明,4种秸秆露天焚烧CO、SO₂、NO_x和CH₄平均排放因子分别在7.39~92.4g/kg、0.11~0.89g/kg、0.72~3.86g/kg和0.2~5.45g/kg之间,PM_2.5平均排放因子在1.48~13.29g/kg之间.OC和EC的质量分别占PM_2.5全部质量的27.7%~54.3%和4.4%~17.1%,是PM_2.5的主要组成成分.污染物排放主要来自混合燃烧状态,焖烧状态排放污染物浓度相对较高.随着含水率升高,焖烧过程增强显著,CO、CH₄、PM_2.5和OC的排放因子升高,其中PM_2.5排放量增高主要是由OC排放占比升高导致.     

Modified Whittaker plots as an assessment and monitoring tool for vegetation in a lowland tropical rainforest

Resource exploitation in lowland tropical forests is increasingand causing loss of biodiversity. Effective evaluation and management of the impacts of development on tropical forests requires appropriate assessment and monitoring tools. We proposethe use of 0.1-ha multi-scale, modified Whittaker plots (MWPs) to assess and monitor vegetation in lowland tropical rainforests.We established MWPs at 4 sites to: (1) describe and comparecomposition and structure of the sites using MWPs, (2) compare these results to those of 1-ha permanent vegetation plots (BDPs),and (3) evaluate the ability of MWPs to detect changes in populations (statistical power). We recorded more than 400 species at each site. Species composition among the sites was distinctive, while mean abundance and basal area was similar. Comparisons between MWPs and BDPs show that they record similarspecies composition and abundance and that both perform equallywell at detecting rare species. However, MWPs tend to record morespecies, and power analysis studies show that MWPs were more effective at detecting changes in the mean number of species of trees 10 cm in diameter at breast height (dbh) and in herbaceous plants. Ten MWPs were sufficient to detect a change of 11% in the mean number of herb species, and they were able to detect a 14% change in the mean number of species of trees 10 cm dbh. The value of MWPs for assessment and monitoringis discussed, along with recommendations for improving the sampling design to increase power.     

Science and values in risk assessment: The case of deliberate release of genetically engineered organisms

To make more responsible decisions regarding risk and to understand disagreements and controversies in risk assessments, it is important to know how and where values are infused into risk assessment and how they are embedded in the conclusions. In this article an attempt is made to disentangle the relationship of science and values in decision-making concerning the deliberate release of genetically modified organisms (GMOs) into the environment. This exercise in applied philosophy of science is based on Helen Longino's contextual empiricism which attempts to reconcile the objectivity of science with its social and cultural construction. Longino distinguishes different levels of research on which values apparently contextual with respect to a given research program can shape the knowledge emerging from that program. Her scheme is applied for locating and identifying the values that affect environment risk assessments of the field experiments with GMOs. The article concludes with some provisional suggestions for the decision process and the role of scientists in it.     

飞机驾驶舱人机几何适配性评价指标研究

飞机驾驶舱人机几何适配性评价对于保障人机效能的充分发挥和飞行安全至关重要。针对一些评价指标制定了相关标准和规范,但未形成一套可操作的指标体系。针对该问题,提出采用改进德尔菲法建立飞机驾驶舱人机几何适配性评价指标体系。通过对现有相关标准、规范和技术数据进行分析研究,初步确定出38个评价指标。针对确定的指标,聘请了飞过多种型号飞机的23名现役有经验飞行员作为专家咨询人员进行了两轮咨询,在对咨询结果进行统计处理的基础上,筛选出了21个评价指标,该指标体系的建立为飞机驾驶舱人机几何适配性综合评价奠定了基础,也可为航空工程部门的评价工作提供科学依据,并有一定的指导作用和实用价值。     

The Magic Bullet Criticism of Agricultural Biotechnology

One common method of criticizing genetically modified organisms (GMOs) is to label them as “magic bullets.” However, this criticism, like many in the debate over GMOs, is not very clear. What exactly is the “magic bullet criticism”? What are its origins? What flaw is it pointing out in GM crops and agricultural biotechnology? What is the scope of the criticism? Does it apply to all GMOs, or just some? Does it point to a fatal flaw, or something that can be fixed? The goal of this paper is to answer these questions and clarify the magic bullet criticism of agricultural biotechnology. It is hoped that the results of this exercise will be helpful in advancing deliberation over the role GMOs and agricultural biotechnology should play in 21st century agriculture.     

改性蛭石吸附性能初探

用酸处理活化蛭石对某些重金属离子最佳吸附条件进行了实验研究，并从蛭石的结构初步探讨了其对某些重金属离子吸附的机理。研究结果表明活化蛭石对某些重金属离子具有较好的吸附性。     

CASS变型工艺污泥膨胀原因分析及控制

在CASS变型工艺处理啤酒废水的可行性研究阶段,由于某种原因造成了污泥膨胀现象,影响了工艺的正常运行。通过对可能导致污泥膨胀的各种原因进行分析,结合实际运行参数进行对比,提出了相应的控制对策,从而确定了污泥膨胀的控制方案并及时实施,使本次膨胀得到了有效的控制。     

改性硅藻土处理城市污水技术的可行性研究

文章分析了改性硅藻土处理城市污水技术的原理,指出改型硅藻土相对于一般的铝盐、铁盐等污水处理剂具有污水处理的效果稳定、产生二次污染少、可回收利用空间大、价格低廉等优点;并提出该技术的常规工艺流程和改进工艺流程,从而从理论上说明该技术在技术上是可行的。结果表明,该技术对COD和BOD5去除效率分别达到70%和73%左右,对SS和TP的去除率分别>94%和92%,从而进一步验证该技术的技术可行性。参照一般的化学强化一级处理技术的经济费用,分析了该技术在经济上的可行性。