猪粪及奶牛粪中温厌氧发酵对Cu和Zn的影响

以猪粪和奶牛粪为发酵原料,在中温〔(37±2)℃〕条件下采用完全混合式厌氧反应器进行了158 d的室内试验研究,分析厌氧发酵过程中Cu和Zn在沼液中质量浓度的变化及其在沼渣中的赋存形态. 结果表明:①猪粪沼液中ρ(TCu)和ρ(TZn)(TCu和TZn分别为总Cu和总Zn)随发酵时间的增加逐渐升高,而奶牛粪沼液中二者变幅不明显. ②整个发酵过程中,猪粪沼液中ρ(TCu)和ρ(TZn)的平均值极显著低于进料(P<0.001),降幅分别为80%和43%;而奶牛粪沼液中二者降幅分别仅为11%和13%. ③猪粪和奶牛粪沼液中ρ(溶解性Cu)占ρ(TCu)的53%和43%,与进料相比有小幅降低;而猪粪和奶牛粪沼液中ρ(溶解性Zn)占ρ(TZn)的35%和19%,极显著高于进料(P≤0.01),增幅分别为109%和37%. ④猪粪和奶牛粪沼渣中Cu主要以可氧化态存在,Zn主要以残渣态和酸溶态/可交换态存在. 中温厌氧发酵对猪粪和奶牛粪中溶解性Cu和Zn的削减效果有限,并且沼渣中残渣态Cu和Zn的减少可能增加二者的生物有效性,因此不利于农田的直接利用.      

UNDERSTANDING A WATERSHED FROM THE BIOLOGICAL VIEWPOINT1

In watershed management the effects of plants on water cannot be considered a constant and forgotten because: plants of different sizes and forms use water at different rates and plants of the same size differ in their needs for water because of anatomical differences. Many common denominators are present in all watersheds covered by vegetation. Forces exerted on the soil water by vegetation, climate and soil are the same kinds of forces. The differences between watersheds in water yield potential appear to be due to differences in the degree in which these forces are exerted. However, the influence of biotic factors are more individual. The similarities and differences existing between watersheds suggest some principles that can be used as guides to understanding individual watershed problems and as possible guides to determining when, how, and where to treat a given watershed. Eleven principles are given and their application to the definition and solution of biological or vegetational problems of watershed management are discussed.     

提高液晶电焊防护片响应速度

论述了提高液晶电焊防护片响应速度的办法，经试验，发现电焊电流产生超前电焊光的时间是13ms。因此可用电焊电流作为触发信号提前开启液晶偏转电路以达到全过程防护的目的。     

谷氨酸晶体分离工艺研究

采用以浅层理论制作的固液分离器对味精生产中的谷氨酸废液和结晶母液进行分离，可加强对细粒级谷氨酸晶体的回收。其分离直径可达12μm。分离效率优于传统的滑槽工艺。     

CHANNEL FORM AND STREAM ECOSYSTEM MODELS1

A system is proposed to classify running water habitats based on their channel form which can be considered in three different sedimentological settings: a cobble and boulder bed channel, a gravel bed channel, or a sand bed channel. Three physical factors (relief, lithology, and runoff) are selected as state factors that control all other interacting parameters associated with channel form. When these factors are integrated across the conterminous United States, seven distinct stream regions are evident, each representing a most probable succession of channel forms downstream from the headwaters to the mouth. Coupling these different channel profiles with typical biotic community structures usually associated with each of the channel types should result in considerable refinement of the applicability of the River Continuum Concept and other holistic ecosystem models by realizing the nonrandomness of the effects of geo-morphology on stream ecosystems. Thus, this regional perspective of streams should serve to make persons concerned with water resources more aware of the geographical considerations that affect their study areas.     

An Ethical Toolkit for Food Companies: Reflections on its Use

Nowadays many debates are going on that relate to the agricultural and food sector. It looks as if present technological and organizational developments within the agricultural and food sector are badly geared to societal needs and expectations. In this article we briefly present a toolkit for moral communication within the food chain. This toolkit is developed as part of a European research project. Next, we discuss what such a toolkit can bring about, given the characteristics of the present day agricultural and food sector and its wider context. We defend that the toolkit can be seen as one of the mechanisms that can help enterprises in the agricultural and food sector to be accountable. It should, however, be complemented with other mechanisms, first, to empower the wider public and, second, to stimulate a dialogue, on a more equal footing, between public authorities, citizens, and economic actors.     

碳基高价银分子晶体电池处理铬污染源水试验研究

以扬州第四水厂的沉淀后出水作为原水,模拟突发铬污染,通过投加碳基高价银分子晶体电池进行应急处理的实验研究。实验结果表明：碳基高价银分子晶体电池对铬的吸附在30min内能达到88.2％的吸附容量;碳基高价银分子晶体电池对铬的吸附符合Langmuir吸附模式;溶液pH值大于5时,吸附几乎为0;对进水质量浓度小于0．75mg／L的铬污染水样,接触时间5min以内便能使出水中铬的质量浓度降到生活饮用水标准的限值0．05mg／L。     

原子吸收光谱法在环境分析中的应用

环境分析是原子吸收光谱法(AAS)的主要应用领域,该技术在国内外发展很快。本文评述了近年来AAS在环境形态分析及环境监测方面的应用进展。     

论环境污染导致健康损害的公共化补偿制度

环境污染导致健康损害的公共化补偿制度具有明显的公益性,在污染频发的当今社会,该制度能起到促进社会和谐的重要作用。我国在借鉴国外先进经验的基础上,应该构建环境污染导致健康损害公共化补偿制度。该制度的主要理论基础就在于行政力量应该成为风险社会背景下抵抗环境污染风险的最终保障,因此其设立和运行着重强调政府责任,国家应该通过其主管的公共化补偿基金,依照法定程序对未能获得救济的健康受害人进行及时的救治和帮助。     

Spatial characteristics analysis by PCR-DGGE for bacterial communities in surface sediments of Tangxi River,Hefei City北大核心CSCD

Microbes play an important role in material circulation and pollutant release in urban sediments, and its community structure can provide an important basis for evaluating the pollution load and ecosystem health of an urban river. In this study, bacterial communities in sediments from different locations of Tangxi River in Anhui Province were analyzed and compared, with an objective of evaluating the effects of aquatic environment on spatial characteristics of bacterial communities and the feasibility of using bacterial community composition as an indicator of urban river health. PCR-DGGE was applied to analyze the bacterial communities; fifteen major bands of 16S rDNA genes fragments from DGGE profiles of sediment samples were further eluted from gel, reamplified and sequenced. The sequences of these fragments were compared with the database in GenBank (NCBI). The collected samples were clustered based on UPGM Aanalysis. In addition, relationships between bacterial communities and environmental factors were analyzed by Monte Carlo test and redundancy analysis (RDA). The DGGE profiles indicated that upstream surface sediments had about 30 bands, but the differences in brightness were not significant. Although midstream surface sediments had only 18 bands on average, the brightness of some bands was relatively high, indicating that some dominant species of bacteria existed in these sediments. The amounts of bands in downstream sediments were between those of upstream and midstream, with some bands of high brightness. The NCBI comparison results showed that ten sequences shared 98-100% homology with known sequences, one with 97%, and the other four with uncultured bacteria. Shannon index (H) of bacterial diversity from upstream surface sediments was 3.31 on average, which was significantly (P < 0.05) higher than that of midstream surface sediments, and slightly higher than that of downstream surface sediments. UPGMA results showed both the distribution of bacteria communities and the diversity were strongly related with the sampling locations (Eigenvalue = 0.188, P = 0.134). Monte Carlo test and RDA analysis showed that the ion exchangeable form of nitrogen (IEF-N) was the main factor influencing the spatial characteristics of bacterial communities in the sediments. The aquatic plants had a significant effect on the richness of bacterial communities in the sediments, and the effectiveness of plant species was more notable than that of the vegetation coverage. The above results indicated that bacterial community structure and diversity in the surface sediments can well reflect the degree of urbanization development and effectiveness of ecological restoration in Tangxi River region.