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711.
分析了2015年重庆市黔江城区2个自动监测站点PM10,SO2,NO2,O3日均值和小时均值,结合同期气象因素,对污染物浓度与气象因素进行分析.表明,PM10、SO2、NO2和O3春季平均值呈显著差异,PM10超标6天,SO2,NO2,O3污染水平较低,未超标;PM10、SO2和NO2呈现早晚双峰型,O3呈典型单峰型;风速与SO2和NO2浓度呈负相关,与O3浓度则呈正相关关系,风速较小时,利于PM10浓度降低,当风速达到一定程度,会导致PM10浓度升高;污染物浓度和相对湿度呈明显负相关;降水对大气污染物有削减作用. 相似文献
712.
Researchers have examined the effects of individual job‐related anxiety on employee attitudes and behaviors but have yet to examine whether team job‐related anxiety would have similar or different effects. Building on prior research on negative group affective tone and creativity, we propose that team job‐related anxiety has an inverted U‐shaped curvilinear relationship with both team and individual creativity. Furthermore, we posit that team cooperativeness moderates those curvilinear relationships. Using a two‐wave research design and matched employee‐supervisor data from 290 employees nested in 65 teams, we found support for the proposed inverted U‐shaped relationships. Moreover, the intermediate level of team job‐related anxiety was associated with higher individual creativity in teams with higher cooperativeness. We conclude the study with a discussion of the theoretical and practical implications of our findings. 相似文献
713.
利用RAPD(随机扩增多态)标记分析湖内鲤、鲫群体遗传多样性,从40个随机引物中各筛选出8个引物适合鲤、鲫群体RAPD扩增。在鲤群体中,共检测出60条带,其中多态性带42条,多态位点比率为70.00%;而在鲫群体中,共检测出61条带,其中多态性带40条,多态位点比率为65.57%。用POPGENE软件分析实验数据,结果显示:湖内鲤群体的遗传多样性水平(He=0.230 1,H0=0.391 0)和鲫群体的遗传多样性水平(He=0.218 6,H0=0.375 8)都较高,都有较大的遗传变异。而在鲤、鲫群体内,雌性群体与雄性群体相比较,其各自的遗传多样性很接近。 相似文献
714.
湖南省主要自然灾害及减灾策略 总被引:8,自引:0,他引:8
本文概述了湖南省的干旱、洪涝、低温冷害、冰雹、风灾、冰冻、农业病虫害、森林火灾水土流失、地震等主要自然灾害的时空分布特征及其对国民经济的影响,并对主要灾害的发展作出了预测,最后提出了减灾策略。 相似文献
715.
716.
采用Fenton试剂氧化-混凝联合工艺对难处理络合铜镍电镀废水进行了研究,考察了废水初始pH值、H2O2初始浓度、[Fe2 ]/[H2O2]、反应时间和温度、混凝液pH、混凝剂质量浓度对处理过程的影响,探讨了废水的降解途径和机理.结果表明,在体系初始pH=4,温度30℃,H2O2投加量为800mg/L,[Fe2 ]/[H2O2]=0.1,反应时间60 min,混凝液pH=8及混凝剂质量浓度为500mg/L的条件下,废水的COD去除率为96.98%,Cu2 为99.91%,Ni2 为99.92%,处理水完全达到国家一级排放标准.同时依据GC/MS对X-GN降解最终产物的分析结果,推导出废水的基本降解机理和途径. 相似文献
717.
Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0. 相似文献
718.
灯心草部分生理生化指标对土壤复合重金属胁迫的响应 总被引:1,自引:0,他引:1
通过盆栽试验,以叶绿素含量和POD、SOD、CAT3种抗氧化酶活性作为观测指标,研究了Cu、Cd、Pb、Zn和As复合重金属胁迫下灯心草部分生理生化指标的变化趋势和机理.结果表明,灯心草的生理毒害效应呈明显的剂量-效应关系.表现为与对照相比,叶绿素含量减少,叶绿素a/b值降低,叶片失绿现象明显.随着复合重金属胁迫浓度的增加,灯心草3种酶活性均呈先升后降的变化趋势,但出现抗性酶活性高峰所对应的重金属浓度不同,表现出不同的特征变化趋势.总体来说,在接近土壤环境质量标准低浓度设计范围内,酶活性有逐渐被激活的趋势.但在高浓度水平下,酶活性普遍受到抑制.生长在铅锌尾矿和模拟矿毒水污染土壤中的灯心草叶绿素合成受到显著抑制(P<0.05),但POD和CAT两种酶活性均高于对照. 相似文献
719.
Zhang ZhH Chai ZF Mao XY Chen JB 《Environmental pollution (Barking, Essex : 1987)》2002,120(1):157-161
Concentrations of 32 elements, Ag, As, Au, Ba, Ca, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, U, W, Yb, and Zn were determined by instrumental neutron activation analysis (INAA) in the early preserved epiphytic lichens (Parmotrema recticulatum) from the remote southwestern China area in the 1960s, 1980s and 1990s. The concentrations of Ag, As, Ce, Cr, Cs, Eu, Fe, Hf, La, Nd, Ni, Sc, Se, Sm, Tb, U, Yb and Zn were dropped down by the temporal prolongation. The elemental concentration levels obtained from the organisms indicate that the extent of heavy metal atmospheric deposition among the sampling sites has been declining during the past decades. 相似文献
720.
This study evaluated the relationship between the breath concentrations of, and personal exposure to, toluene, xylene and ethylbenzene of thirty workers from ten gasoline stations. Personal exposure air samples and workplace samples were collected simultaneously. Each subject provided a sample of exhaled breath after his or her personal exposure air was sampled. Twenty-five personal air, 17 workplace and 30 breath samples were collected in this study. Results indicated that breath concentrations of toluene and xylene were significantly correlated with personal monitoring concentrations. Furthermore, multiple regression analysis showed that exhaled toluene levels were highly influenced by personal toluene concentrations and the amount of personal gasoline sold (r2 = 0.762), while exhaled xylene levels depended on wind speed and personal xylene exposure concentrations (r2 = 0.665). Exhaled ethylbenzene levels were too low to present a relationship between concentrations and personal exposure levels. The exhaled toluene, xylene and ethylbenzene concentrations ranged from 4.3 to 41.8, 0.9 to 13.9, and 0.2 to 6.5 ppb, and the corresponding personal monitoring concentrations ranged from 60.3 to 572.3, 16.4 to 156.6, and 10.7 to 136.6, respectively. The average number of symptoms per person, according to neurotoxic questionnaire 16 (abbreviated as Q16) was 4.1 and six workers showed over six symptoms in Q16. This study suggests that exhaled toluene and xylene levels are suitable for use as biological exposure indices even at the ppb-level of exposure. Gasoline service workers are exposed to high levels of volatile organic compounds (VOCs) and the potential threats to their neurological systems deserve further investigation. 相似文献