制氧企业安全评价方法探讨

本文针对制氧行业的生产特点以及安全管理情况,对作业过程中存在的危险、有害因素进行了分析,综合运用安全检查表法(SCL)与故障模式、影响及危险度分析法(FMECA)对制氧企业安全现状进行了评价,并提出了相应的对策措施.结果表明:安全检查表法简便、易于掌握、较为实用;故障模式、影响及危险度分析法对评价人员的要求较高,但可得...     

内分泌干扰物在城市污水处理厂中的行为和归趋：综述

内分泌干扰物作为一类新型污染物,由于其在环境水体中微量的浓度即可对野生动物产生内分泌干扰效应,因此引起了人们的广泛关注.本文以两类主要内分泌干扰物(即类固醇雌激素和酚类内分泌干扰物)作为研究对象,综述了它们在城市污水处理厂中的浓度水平以及相应的去除效率,并探讨了不同生物处理工艺、运行操作条件等对去除效率的影响.此外,通...     

酚类雌激素酶催化降解性的QSAR分析

以分子电性距离矢量(MEDV-13)和原子类型电拓扑状态指数(ETSI)2种分子结构描述符,分别有效表征了15个酚类雌性激素的分子结构,应用基于预测的变量选择与模型化(VSMP)方法分别建立了该类化合物经辣根过氧化物酶(HRP)催化氧化的速率常数(InkCAT)与分子结构的定量相关模型.以MEDV-13为分子描述符建立的模型显示:影响去除效果的主要结构因素是由5个MEDV描述子表达的5个子结构碎片,即-CH3、-CH2、-O-、-OH和-cCc,以ETSI为分子描述符所建模型表明:影响该反应速率的主要结构因素是由5个ETSI描述子对应的5个子结构碎片,即-CH3、-CH2、-O-、-OH和>C<.所建模型的估计相关系数分别为0.92和0.93,LOO检验相关系数分别为0.84和0.85,表明2种模型均具有良好的估计能力与稳健性,以上结果说明.虽然酚类雌激素的种类、结构多样,但决定其HRP酶催化去除效果的关键结构因素是酚环上所有取代基整体给电子能力的强弱.     

Economic analysis of effects on cultivated land following China's entry to the WTO

Inspired by the phenomenon of heavy reduction in the area of cultivated land following the entry of Korea and Japan to the WTO,countries with a large population and inadequate amount of cultivated land similar to China,this paper raises the problem of the potential effects on cultivated land in China following its entry to the WTO.The paper attempts analysis,using economic principles,of the effects of Chinese WTO membership on cultivated land from four aspects;tariff concessions,quota increment,comparative advantage,and the substitution principle.And the conclusion is mat China's entry to WTO may lead to a reduction in cultivated land.Finally,some countermeasures are proposed to resolve the problem.     

Quantifying the rebound effects of residential solar panel adoption

Customers who adopt solar panels can reduce their energy bills and lower the effective average electricity prices they pay. When the price falls, a solar consumer might consume more electricity than before – a solar rebound effect. We provide the first empirical evidence of residential solar rebound effects in the U.S. We use household level hourly and daily electricity meter data as well as hourly solar panel electricity generation data from 277 solar homes and about 4000 non-solar homes from 2013 to 2017 in Phoenix Arizona. Using matching methods and a fixed effects panel regression approach, we find that when solar electricity generation increases by 1 kWh, solar homes increase their total electricity consumption by 0.18 kWh. This indicates that solar rebound effects are estimated at 18%. Building upon our theoretical framework, the increase in consumer surplus from solar panel adoption is estimated at $972/yr.     

Investigating cumulative effects across ecological scales

Species, habitats, and ecosystems are increasingly exposed to multiple anthropogenic stressors, fueling a rapidly expanding research program to understand the cumulative impacts of these environmental modifications. Since the 1970s, a growing set of methods has been developed through two parallel, sometimes connected, streams of research within the applied and academic realms to assess cumulative effects. Past reviews of cumulative effects assessment (CEA) methods focused on approaches used by practitioners. Academic research has developed several distinct and novel approaches to conducting CEA. Understanding the suite of methods that exist will help practitioners and academics better address various ecological foci (physiological responses, population impacts, ecosystem impacts) and ecological complexities (synergistic effects, impacts across space and time). We reviewed 6 categories of methods (experimental, meta-analysis, single-species modeling, mapping, qualitative modeling, and multispecies modeling) and examined the ability of those methods to address different levels of complexity. We focused on research gaps and emerging priorities. We found that no single method assessed impacts across the 4 ecological foci and 6 ecological complexities considered. We propose that methods can be used in combination to improve understanding such that multimodel inference can provide a suite of comparable outputs, mapping methods can help prioritize localized models or experimental gaps, and future experiments can be paired from the outset with models they will inform.     

Potential Negative Ecological Effects of Corridors

Despite many studies showing that landscape corridors increase dispersal and species richness for disparate taxa, concerns persist that corridors can have unintended negative effects. In particular, some of the same mechanisms that underlie positive effects of corridors on species of conservation interest may also increase the spread and impact of antagonistic species (e.g., predators and pathogens), foster negative effects of edges, increase invasion by exotic species, increase the spread of unwanted disturbances such as fire, or increase population synchrony and thus reduce persistence. We conducted a literature review and meta‐analysis to evaluate the prevalence of each of these negative effects. We found no evidence that corridors increase unwanted disturbance or non‐native species invasion; however, these have not been well‐studied concerns (1 and 6 studies, respectively). Other effects of corridors were more often studied and yielded inconsistent results; mean effect sizes were indistinguishable from zero. The effect of edges on abundances of target species was as likely to be positive as negative. Corridors were as likely to have no effect on antagonists or population synchrony as they were to increase those negative effects. We found 3 deficiencies in the literature. First, despite studies on how corridors affect predators, there are few studies of related consequences for prey population size and persistence. Second, properly designed studies of negative corridor effects are needed in natural corridors at scales larger than those achievable in experimental systems. Third, studies are needed to test more targeted hypotheses about when corridor‐mediated effects on invasive species or disturbance may be negative for species of management concern. Overall, we found no overarching support for concerns that construction and maintenance of habitat corridors may result in unintended negative consequences. Negative edge effects may be mitigated by widening corridors or softening edges between corridors and the matrix. Other negative effects are relatively small and manageable compared with the large positive effects of facilitating dispersal and increasing diversity of native species. Efectos Negativos Potenciales de los Corredores     

二元联合作用藻红外测试方法——以重金属为例

为检验二元联合作用藻红外测试方法的可行性,用Cu~(2+)、Fe3+、Mn~(2+)、Al3+、Cr3+、Hg~(2+)、Cd~(2+)、Pb~(2+)、Zn~(2+)进行了二元联合作用测试实验。结果显示:联合药液的参照浓度与单药液的参照浓度比为0.5:0.25的有15组二元组合,为2.0:1.0的有10组二元组合,为1.0:0.5的有11组二元组合;在9种重金属的36组二元联合作用测试结果中出现拮抗作用、相加作用、协同作用,表明联合作用类型表现出多样性;14组拮抗作用中单组的再现性为50%~100%、多组的再现性的出现率为93%、单组的重现性为67%~100%、多组的重现性的出现率为100%,21组相加作用中单组的再现性为50%~100%、多组的再现性的出现率为86%、单组的重现性为67%~100%、多组的重现性的出现率为100%,1组协同作用重现性67%;36组联合作用测试结果的再现性为50%~100%、再现性的出现率为86%,重现性为67%~100%、重现性的出现率为100%。上述分析可知,9种重金属的36种二元联合作用测试结果具有较好的多样性、再现性、重现性,表明测试条件、藻温测试方法、三指标评价法能够保证藻响应温差和藻响应药品评价结果的质量,参照浓度分析方法、联合作用评价方法能够控制联合作用分析结果的质量;藻响应的有毒有害物都存在敏感浓度,用参照浓度分析方法可分析出藻响应有毒有害物的参照浓度。因此,藻红外测试技术可以用于测试重金属、农药、有机药品、抗生素等的二元联合作用。     

大气中有机胺类物质反应机理和消除过程研究

综述大气中有机胺可能的来源、健康危害及其在大气中的均相和非均相化学转化机制,阐述有机胺的反应产物对二次有机气溶胶及其对大气气溶胶的物理和化学性质的改变,此类改变增强大气气溶胶间接气候效应(如成云结核能力等)。大气中的有机胺主要通过与大气氧化剂的反应和非均相反应过程的溶解或置换进入颗粒相,而后随着湿沉降(如云滴、雾滴、雨滴等)到达地面或海面。     

苦味酸测定中关键问题的研究

目前测定苦味酸的国标方法为《生活饮用水标准检验方法有机物指标》(GB/T 5750.8—2006)中的衍生物-液液萃取-气相色谱法,在实际测试过程中,发现水样pH值和基质效应会影响苦味酸测定。当pH值为8~12时,生成的氯化苦响应强度变化不大;在pH约为13时,响应强度最大。水质中除腐殖酸、硝基甲烷及2,4,6-三硝基甲苯会影响苦味酸测定外,硝基酚类和甲基酚类同样起到正干扰作用,因此,国标方法不能全面和准确地测定水中的苦味酸含量。