检索结果-南通市图书馆

Hydrolytic　dynamics　of　pesticide　N＇－（2，4－dimethylphenyl）－N－methylformamidine　in　aquatic　solution

在线全文

学校读者我要写书评

暂无评论

Journal of environmental sciences 1996年第2期8卷 185-190页

作者： mo hanhong yang kewu An fengchun Liu Ye (research center for eco-environmental sciences, chinese academy of sciences, beijing 100085, china) Res. Ctr. for eco-Environ. sciences Chinese Academy of Sciences Beijing 100085 China

The hydrolytic dynamics of pesticide N' -(2,4-dimethylphenyl)-N-methylformamidine (DMA) in aquatic solution and its degradation in simulated aquatic ecosystem were investigated. The results showed that the compound was not very stable in aqueous solution and easily decomposed in alkaline solution. It was stable below pH5 and there was obvious tendency that the compound was easily decomposed when PH was greater than 6. The reaction rate constant of DMA increased with increasing of either pH value Or temperature of reaction medium. The half-life values of hydrolysis for DMA at 25℃ were 15. 92 days at pH 6, and 1. 40 days at pH 9 , respectively. The temperature coefficient and activation energy of hydrolysis for DMA was 2. 9 and 78. 74kJ. mol-1 , respectively. The degradation of DMA in simulated aquatic ecosystem was similar to that in buffer solution in the laboratory. The half-life values of degradation for DMA at 26℃ in simulated aquatic ecosystem were 3. 23 days at pH 9. 13 and 1. 41 days at pH 8. 28 , respectively.

关键词： pesticide N'- ( 2,4-dimethylphenyl)-N-methylformamidine hydrolysis degradation.

In situ reconstruction induced oxygen-deficient multiphase Cu based species hybridized with Ni single atoms as tandem platform for CO_(2) electroreduction

在线全文

学校读者我要写书评

暂无评论

Nano research 2024年第5期17卷 3888-3894页

作者： Juzhe Liu Yuheng Wang Pengpeng mo Feng yang Kaiqi Jiang Zhixiang Cheng Yuxuan Liu Zhiyi Sun Zheng Liu Yimei Zhang Wenxing Chen The Key Laboratory of Resources and environmental System Optimization Ministry of EducationCollege of Environmental Science and EngineeringNorth China Electric Power UniversityBeijing 102206China Energy&Catalysis center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China State Key Laboratory of environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China

Tandem catalysis,capable of decoupling individual steps,provides a feasible way to build a high-efficiency CO_(2) electro-conversion system for multicarbons(C_(2+)).The construction of electrocatalytic materials is one of focusing ***,we fabricated a single atom involved multivalent oxide-derived Cu composite material and found it inclined to reconstruct into oxygen-deficient multiphase Cu based species hybridized with monatomic Ni on N doped C *** this prototype,rapid CO generation and C-C coupling are successively achieved on NiN4 sites and surface amorphized Cu species with defects,resembling a micro-production *** this way,the in situ formed tandem catalyst exhibited a high Faradaic efficiency(FE)of~78%for C_(2+)products along with satisfactory durability over 50 ***,the reconstruction-induced amorphous layer with abundant asymmetric sites should be favorable to improve the ethanol selectivity(FE:63%),which is about 10 times higher than that of the non-tandem Cu-based contrast *** work offers a new approach for manipulating tandem catalyst systems towards enhancing C_(2+)products.

关键词： tandem catalysis single atom reconstruction amorphous CO_(2)reduction reaction

Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the Early Cambrian,SW china:Constraints from in situ LA-ICP-MS Analysis of Pyrite

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2024年第2期98卷 416-429页

作者： yang Zhen FU Yong LI Chao CAI Xi GUO Chuan College of eco-environmental Engineering Guizhou Minzu UniversityGuiyang 550025China College of Resources and environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and the Environment Ministry of EducationGuizhou UniversityGuiyang 500025China National research center for Geoanalysis Chinese Academy of Geological SciencesBeijing 100037China

A polymetallic layer is usually developed at the bottom of the early Cambrian black shale in Guizhou *** mineral that makes up the polymetallic layer is related to the sedimentary *** analyze the differentiation mechanism between polymetallic deposits(Ni-mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of *** results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan *** isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional *** sulfur in the Ni-mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from ***,the Ni-mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

关键词： sedimentary environment black shale polymetallic layer pyrite early Cambrian

Effects of combined substitution of Dy and mo or Si on the crystal structures and magnetic properties of Nd_(1-y)Dy_yFe_(11-x)TiM_x(M=mo,Si) compounds

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2009年第8期52卷 1097-1103页

作者： LI XiangJun,ZHENG Na,HU ZhongBo & YUAN ZhuoBin College of Chemistry and Chemical Engineering,Graduate University of chinese academy of sciences,beijing 100049,china College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing China

A series of Nd1-yDyyFe11-xTiMx(M=mo,Si) alloys have been prepared by arc melting and studied by X-ray diffraction and neutron *** samples are found to crystallize in the ThMn12-type *** lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTimox alloys increase linearly with increasing content of mo(x),while the lattice parameters a and c and unit cell volume V of Nd0.5Dy0.5Fe11-xTiSix alloys decrease linearly with increasing content of Si(x).In NdyDy1-yFe11-xTiMx(M=mo,Si) compounds,Ti and mo atoms preferentially occupy the 8i sites and Si atoms preferentially occupy the 8j and 8f *** measurements show that the substitution of Fe by either mo or Si leads to a decrease in the Curie temperature.

关键词： rare earth-transition metal compounds crystal structure X-ray diffraction neutron diffraction

在线全文

学校读者我要写书评

暂无评论

北京大气环境中的重金属元素

环境科学 1988年第6期9卷 12-17页

作者：汪安璞黄衍初杨淑兰中国科学院生态环境研究中心

重金属进入环境后会广泛分布于大气、水体、土壤和生物体中。它会长期积累、长程迁移或与其它物质发生化学反应生成有害物质。大气环境中的重金属元素有来自工业生产中的排放物,机动车的排气,燃煤燃油的产物;也有来自天然来源,如风砂、... 详细信息

重金属进入环境后会广泛分布于大气、水体、土壤和生物体中。它会长期积累、长程迁移或与其它物质发生化学反应生成有害物质。大气环境中的重金属元素有来自工业生产中的排放物,机动车的排气,燃煤燃油的产物;也有来自天然来源,如风砂、土壤或扬尘。这些重金属一般以颗粒状态分散于大气中,会进入人体呼吸系统,被血液吸收而危害健

关键词：重金属元素粗粒细粒总悬浮颗粒物非采暖期大气环境地理环境北京

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

广西典型行业VOCs排放源成分谱特征

环境化学 2024年第5期43卷 1732-1742页

作者：张达标杨俊超穆奕君毛敬英董慧峪覃纹黄喜寿莫招育粟少丽黄炯丽刘绍刚广西壮族自治区环境保护科学研究院南宁530022 中国科学院生态环境研究中心中国科学院饮用水科学与技术重点实验室北京100085 广西民族大学化学化工学院林产化学与工程国家民委重点实验室广西高校应用分析化学重点实验室南宁530006

挥发性有机物(VOCs)作为臭氧生成的重要前体物,摸清其排放源成分谱特征,是破解臭氧污染防治难题的关键所在.当前,广西臭氧污染日益凸显,然而VOCs排放底数仍模糊不清.针对此问题,本研究对广西包装印刷、家具制造、汽车维修、岗石制造、... 详细信息

挥发性有机物(VOCs)作为臭氧生成的重要前体物,摸清其排放源成分谱特征,是破解臭氧污染防治难题的关键所在.当前,广西臭氧污染日益凸显,然而VOCs排放底数仍模糊不清.针对此问题,本研究对广西包装印刷、家具制造、汽车维修、岗石制造、人造板制造等5个典型行业VOCs排放进行采样,分析115种VOCs组分,探究其VOCs排放浓度水平、源成分谱特征及臭氧生成潜势.结果表明,包装印刷行业VOCs的浓度相对最高(12.98 mg·m^(−3)),是其余4个行业的2—86倍,其次分别为家具制造(5.72 mg·m^(−3))、汽车维修(1.34 mg·m^(−3))、岗石制造(0.84 mg·m^(−3))、人造板制造(0.15 mg·m^(−3))行业,其中,包装印刷行业排放以烷烃(55.37%)为主,其次是OVOCs(27.51%);家具制造行业以OVOCs(50.98%)排放为主,其次是芳香烃(31.05%);汽车维修行业以芳香烃(32.25%)为主,其次是OVOCs(23.76%);岗石制造行业组成以烷烃(42.43%)排放为主,其次是芳香烃(23.76%);人造板制造行业以OVOCs(52.05%)排放为主,其次是芳香烃(14.32%).臭氧生成潜势计算结果显示,臭氧生成潜势大小依次为家具制造(22.62 mg·m^(−3))>包装印刷(17.24 mg·m^(−3))>汽车维修(4.29 mg·m^(−3))>岗石制造(1.44 mg·m^(−3))>人造板制造(0.50 mg·m^(−3))行业,5个行业中对臭氧生成潜势贡献最大的关键物种依次分别为己醛(44.21%)、2-甲基己烷(9.76%)、间/对-二甲苯(24.61%)、苯乙烯(29.27%)、乙醛(23.86%).针对家具制造、汽车维修、岗石制造、人造板制造行业的VOCs治理及其引起的臭氧污染防控应重点关注臭氧生成潜势贡献率大的关键VOCs物种.

关键词：典型行业挥发性有机物源谱特征广西

维普期刊数据库博看期刊

同方期刊数据库

在线全文

学校读者我要写书评

暂无评论

基于卫星遥感的兴凯湖水资源特征变化研究

中国水利水电科学研究院学报（中英文） 2024年第4期22卷 397-410页

作者：郜玉青曹永强么嘉棋王菲莫凡温振辽宁师范大学地理科学学院辽宁大连116029 天津师范大学京津冀生态文明发展研究院天津300387 自然资源部国土卫星遥感应用中心北京100048 山东科技大学测绘与空间信息学院山东青岛266590

随着全球气候变化和人类活动的加剧,湖泊水资源的动态变化成为生态领域的关键研究课题。湖泊作为地球陆地生态系统中不可或缺的组成部分,其水文特性的变化直接影响着区域水循环、生态平衡和人类福祉。研究湖泊动态变化可为气候系统和人... 详细信息

随着全球气候变化和人类活动的加剧,湖泊水资源的动态变化成为生态领域的关键研究课题。湖泊作为地球陆地生态系统中不可或缺的组成部分,其水文特性的变化直接影响着区域水循环、生态平衡和人类福祉。研究湖泊动态变化可为气候系统和人类活动的影响机制提供参考。兴凯湖是位于气候敏感区且受人类活动显著影响的内陆湖泊,本文旨在通过ICEsat-1/2、Landsat及GRACE等多源卫星遥感数据深入分析其水资源的动态变化,并结合气象数据与土地利用数据探索气候变化和人类活动对湖泊的影响。结果表明:(1)ICEsat-1监测的兴凯湖2003—2009年年内水位呈现周期性波动,年际水位呈上升趋势;ICEsat-2监测的兴凯湖2018—2022年年内年际水位呈下降趋势,多轨数据显示水剖面变化趋势一致。(2)2003—2021年兴凯湖面积以增加为主,东部与南部增加最明显。(3)GRACE反演的兴凯湖水储量变化呈上升趋势,且季节变化为春季>冬季>夏季>秋季。湖泊水体变化特征与降水有较高的相关性。研究结果可为流域的水资源综合利用与制定生态环境保护措施提供理论依据。

关键词： ICEsat-1/2 Landsat GRACE 兴凯湖水资源

同方期刊数据库博看期刊

生物碳基纳米钯铜催化剂的优化制备及脱硝研究

在线全文

学校读者我要写书评

暂无评论

中国环境科学 2024年第5期44卷 2460-2472页

作者：莫晓馨张立浩吴雨晴董翼朱宗强朱义年桂林理工大学环境科学与工程学院广西桂林541006 桂林理工大学广西环境污染控制理论与技术重点实验室广西桂林541006 岩溶地区水污染控制与用水安全保障协同创新中心广西桂林541006 中国科学院生态环境研究中心饮用水科学与技术重点实验室北京100035

针对目前高效处理水体硝酸盐污染的技术瓶颈,以毛竹生物碳为载体基材,通过湿化学-浸渍还原的手段制备生物碳基纳米钯铜双金属催化剂(Nano-PdCu-BC),并以其为粒子电极,协同传统的二维电化学反应器,搭建三维粒子电催化反应体系去除水体中... 详细信息

针对目前高效处理水体硝酸盐污染的技术瓶颈,以毛竹生物碳为载体基材,通过湿化学-浸渍还原的手段制备生物碳基纳米钯铜双金属催化剂(Nano-PdCu-BC),并以其为粒子电极,协同传统的二维电化学反应器,搭建三维粒子电催化反应体系去除水体中的硝酸盐污染物.探究了催化剂制备的前驱液浓度、初始硝酸盐氮浓度、电流强度、催化剂投加量和初始pH值对电催化还原NO_(3)-N的影响.结果显示,通过浸渍还原的方法可以将钯铜双金属成功负载在毛竹生物碳载体上,获得纳米钯铜双金属催化剂.在前驱液为0.60g/LPdCl_(2)和0.15g/LCuCl_(2)的溶液组合,初始硝酸盐氮(NO_(3)-N)浓度为100mg/L、电流强度为220mA、初始pH值为7,催化剂投加量为0.80g/L的条件下,反应180min后硝酸盐氮去除率可达99.68%,N_(2)选择性约为44.25%;Nano-PdCu-BC电催化还原NO_(3)-N的反应符合一级反应动力学,反应动力学常数k值为0.034/min;经3次循环使用后,NO_(3)-N去除率仍维持在95%以上,N_(2)选择性保持在40%以上;揭示了纳米钯铜双金属催化剂电催化还原硝酸盐的机理,纳米零价Cu位点吸附NO_(3)-N后被氧化为CuO,提供电子促进NO_(3)-N还原为NO_(2)-N,协同纳米零价Pd,通过为吸附激活原子氢H*间接还原NO_(3)-N,达到将NO_(3)-N还原为NH_4和N_(2)的目的.

关键词：毛竹生物碳硝酸盐纳米钯铜催化剂电催化还原原子氢自由基

同方期刊数据库

Impact of land use and land cover changes on carbon storage in rubber dominated tropical Xishuangbanna,South West china

在线全文

学校读者我要写书评

暂无评论

ecosystem Health and Sustainability 2021年第1期7卷 121-134页

作者： Chaya Sarathchandra Yirga Alemu Abebe Fiona Ruth Worthy Iresha Lakmali Wijerathne Huaixia Ma Bi Yingfeng Guo Jiayu Huafang Chen Qiaoshun Yan Yanfei Geng Dayani SWeragoda Li-Li Li yang fengchun Sriyani Wickramasinghe Jianchu Xu State Key Laboratory of Urban and Regional ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201YunnanChina University of chinese academy of sciences Beijing 100049China Department of Biological science Faculty of Applied SciencesRajarata University of Sri LankaMihintale Sri Lanka State Key Laboratory of Super Lattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing China Department of Electrical and computer engineering Faculty of Electrical EngineeringInstitute of TechnologyHawassa UniversityHawassaEthiopia World Agroforestry Centre(ICRAF) East and Central Asia Regional OfficeKunming YunnanChina Ailaoshan Station for Subtropical Forest ecosystem Studies Chinese Academy of SciencesJingdongYunnan College of Tea science Guizhou UniversityGuiyang China Carbon Consulting Company Colombo Sri Lanka center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnanChina Yibin Vocational and Technical College YibinSichuanChina School of chinese Medicinal Material Resources Guangdong Pharmaceutical UniversityChina

Land use and land cover(LULC)play a significant role in carbon ***-china accounts for~65%of china’s carbon *** Xishuangbanna(South-china),rubber is expanding rapidly creating an urgent need to understand and monitor LULC change and how spatial variation affects carbon storage(CS).This is vital for the formation and implementation of better land use management *** studied LULC changes of 22-year period;addressing how these changes have affected the *** quantified LULC changes between1988 and 2010 using remote sensing methods and calculated CS changes using *** showed that between 1988 and 2010,the rate of deforestation accelerated to 203.2 km^(2)y^(−1)and~23%of forest were *** of natural forest to rubber was responsible for 78%of this *** expansion rate was 153.4 km^(2)y^(−1).Changes to LULC drove a temporal CS reduction 0.223 Tg C/km^(2).Local stakeholders have strong economic interest in converting land to more profitable *** efforts is required to control land conversion through new policies and incentives to retain natural *** of specific potential land use change will be required to avoid promoting the conversion of high carbon storage land uses to low carbon storage land uses.

关键词： Carbon storage deforestation economic plantations ecosystem services land cover changes land use