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1.
为研究石家庄市在"利剑斩污"行动管控期和非管控期挥发性有机物(VOCs)的污染特性变化,在2个时间段内对石家庄市3个国控点进行采样分析。通过苏玛罐(SUMMA罐)进行样品采集,利用气相色谱/质谱联用(GC/MS)仪对石家庄市区3个国控点的VOCs进行定性定量检测分析。结果表明,监测期间主要的特征污染物是二氯甲烷、二氯丙烷、苯和甲苯。与非管控期间相比,管控期间各污染物的质量浓度均有所降低,总VOCs平均质量浓度降低45.107μg/m~3,二氯甲烷质量浓度降低8.796μg/m~3,二氯丙烷质量浓度降低3.750μg/m~3,苯质量浓度降低18.285μg/m~3,甲苯质量浓度降低16.895μg/m~3。大气环境调控策略的实施,有效降低了VOCs浓度,减少了空气污染程度,空气质量改善效果显著。"利剑斩污"行动期间采取的相关举措,对于制定常态化下VOCs的防治对策具有一定的参考价值。  相似文献   
2.
桑叶配方颗粒迄今尚没有统一的质量标准。为提升桑叶配方颗粒的内在质量,对其物质基准评价方法进行了研究。选取具有代表性产地的15批桑叶制备物质基准,采用高效液相色谱法,以芦丁、异槲皮苷、紫云英苷作为评价指标,确定桑叶物质基准的出膏率范围、标志性成分含量及转移率范围,采用超高效液相色谱法,建立物质基准UPLC特征图谱,并对其主要成分进行指认。结果表明:15批物质基准中,芦丁转移率为19.94%~34.05%,异槲皮苷转移率为11.67%~43.58%,紫云英苷转移率为10.73%~43.05%;物质基准特征图谱中,标定了14个共有峰,指认出7个色谱峰,分别为新绿原酸、绿原酸、咖啡酸、芦丁、异槲皮苷、槲皮素-3-O-(6″-O-丙二酰基)-β-D-葡萄糖苷、紫云英苷。所建立的基准评价方法为桑叶配方颗粒质量标准的制定及其后续大规模生产提供了数据基础。  相似文献   
3.
This is the first paper to show that participation in an international environmental agreement has some effectiveness. Our identification strategy consists of applying difference-in-differences techniques in a panel data framework to various levels of data aggregation. We find that ratification of the Rotterdam Convention (RC) and the Stockholm Convention (SC) leads to a reduction in trade of hazardous substances from OECD to non-OECD countries. In particular, we find that when the exporter ratifies the RC, there is a reduction in the import of hazardous chemicals of about 7 percent. In the case of the SC, the results show significant reductions of around 16 percent in trade shipments of persistent organic pollutants. This reduction is more than double the effect found for the RC, which was expected due to a more restricted obligation imposed by the SC convention.  相似文献   
4.
We study the factors influencing the percentage of organic and fair trade certified coffee sold through a cooperative by growers of five cooperatives in Mexico. The percentage of coffee sold through the cooperative was used as a proxy of growers’ engagement with a cooperative. Using factor analysis and a fractional probit regression, we evaluated the proposition that the level of engagement can be explained by transaction cost economics, social norms and connections, and farmer and farm business characteristics. We found that farm size, uncertainty regarding cooperative time of payment to the members and cooperative commitment on price to be paid negatively influence the level of engagement. In contrast, asset specificity, relational commitment, and price have a positive impact on engagement. Our results may help cooperatives and policy makers to build strategies aiming to increase this level of engagement. This is relevant because lower grower engagement has been found to be positively correlated with weak performing cooperatives.  相似文献   
5.
Several consumer studies have shown considerable market potential for sustainable meat products, however, their markets shares are still marginal. In Germany, the sustainable aspects “organic,” “local origin,” and “animal welfare” are of special interest. To obtain a precise overview of potential target groups for these meat categories and their choice of store format, 620 German consumers were surveyed on their attitudes toward sustainable meat production and their shopping behavior. First, target groups based on consumers’ attitudes were identified by cluster analysis, taking into account possible overlaps. Consumers were also clustered by their store format choice and their preferred type of meat packaging. A cross tabulation of the results then provided insights into which store format and type of meat packaging is preferred by the target groups for sustainable meat products. Due to overlaps found in the target groups, the existence of important subgroups was shown. Amongst the target groups, only a slight preference for unpackaged meat products was found. Basically, the offer of sustainable meat products appears of interest for all store formats, with particular emphasis on supermarkets. The results of this study can support producers and retailers developing new and tailored marketing strategies for sustainable meat products.  相似文献   
6.
While organic food is based on well-defined production criteria, the criteria for ‘local’ food are less clear. This study investigates the preferences and trade-offs of distinct consumer segments relative to organic production and several dimensions of local food (sales channel, size of company, and geographical location of animals used in the production). The analysis is based on a quantitative survey of 505 Danish consumers and a choice experiment involving beef salami. Data were analyzed in a principal component and a latent class analysis. We identify five consumer segments whose preferences for organic and local product attributes differed substantially. Most respondents considered geographical proximity in the raising of cattle to be the most important attribute and a third of the consumers were willing to pay a premium for organic salami. The segmentation provides more detailed information about stated consumer behavior than what is typically elicited when considering only average consumer behavior.  相似文献   
7.
[目的]过量施用化肥导致水体富营养化是造成洱海流域上游面源污染的主要原因之一,调查分析农户减少化肥用量和采用有机肥的意愿有助于了解其调整施肥结构的行为。当前研究忽视了农户减少化肥施用强度和采用有机肥的意愿间的替代性,未能开展联立研究。[方法]基于洱海流域上游397个水稻种植户的问卷调查数据,通过Bivariate-Probit模型对农户减少化肥用量和采用有机肥两种意愿进行分析。[结果]年龄负向影响农户减少化肥量的意愿,农户对有机肥好处的认知正向影响其减少化肥量的意愿,农户参加农业社会化服务对其减少化肥用量和采用有机肥的意愿均产生正向影响,相比之下,对农户采用有机肥意愿的促进作用更大。[结论]引导农户参加农业社会化服务以及加强宣传和培训,提高农户对有机肥作用的认知可能是加强其减少化肥用量和增加有机肥施用量意愿的有效途径。  相似文献   
8.
The rise of the natural and organic products market follows a global trend of increasing demand largely due to the growth of environmental awareness and the concern of having a healthier diet. Thus, the objective of this study is to propose and test a theoretical model based on antecedent constructs of perceived value and repurchase intention on the consumption of organic products. The results, based on 256 consumers of organic products, confirm the positive relationship between environmental awareness and perceived quality, healthy consumption, and perceived price fairness. Moreover, they underpin the influence of healthy consumption, perceived price fairness and perceived quality on perceived value, and lastly, the influence of perceived value on repurchase intention. Therefore, this study can help practitioners and consumers comprehend in a more systematic way the buying behaviour of this food category.  相似文献   
9.
明谦 《价值工程》2014,(19):316-317
本文介绍了一种处理有机硅废水的新的工艺组合,即铁炭微电解——水解酸化——UASB——MBR联合处理法,第一步铁炭微电解很明显的改善了有机硅原水的可生化性,BOD/COD值可达0.52;进入水解酸化池后,部分大分子降解成小分子物质,可生化性进一步提高;随后进入UASB,在颗粒污泥的作用下,COD去除率达到81%;在曝气池中,设置MBR,进一步去除了COD,去除率为96%;最终出水能达标排放。  相似文献   
10.
费平  赵秀  金海玉 《价值工程》2015,(5):307-309
头道桥糜棱岩是以塑性变形为主的韧性剪切带,形成了糜棱岩、碎裂岩系列,该糜棱岩带中糜棱岩的原岩均为花岗岩,该韧性剪切带中的糜棱岩化花岗岩、花岗质初糜棱岩以及花岗质糜棱岩的单矿物化学特征和岩石地球化学特征与岩石变形强度增大和退变质作用增强有着密切的关联,他们都表现出了一定的规律性。  相似文献   
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