检索结果-南通市图书馆

Effect of allelochemicals sustained-release microspheres on the ingestion, incorporation, and digestion abilities of Daphnia magna Straus

引用

Journal of Environmental Sciences 2023年第2期124卷 205-214页

作者： Benhang Li Yijun Yin Xiaohong Zhou Li Feng Yongze Liu Ziwen Du yajun tian Liqiu Zhang Beijing Key Laboratory for Source Control Technology of Water Pollution Engineering Research Center for Water Pollution Source Control and EcoremediationBeijing Forestry UniversityBeijing 100083China College of Environment Zhejiang University of TechnologyHangzhou 310014China

Allelochemicals sustained-release microspheres(ACs-SMs)exhibited great inhibition effect on algae,however,few studies have focused on ACs-SMs toxicity on invertebrate.In this study,the effects of single high-concentration ACs(15 mg/L,SH-ACs),repeated lowconcentration ACs(3×5 mg/L,RL-ACs)and ACs-SMs containing 15 mg/L ACs exposure on the ingestion,incorporation,and digestion of Daphniamagna Straus(DS)were investigated by stable isotope 15N labeling method.Meanwhile,the diversity and abundance of microflora in DS guts were determined by 16S rRNA genes and cloning methods.The results showed that SH-ACs exposure caused 50%and 33.3%death rates for newborn and adult DS,while RL-ACs exposure caused 10%death rate for newborn DS and no obvious effect on the activity of adult DS.And ACs-SMs exposure did not diminish the motility of both newborn and adult DS,indicating the lower acute toxicity of ACs-SMs.Furthermore,SH-ACs inhibited the ingestion(-6.45%),incorporation(-47.1%)and digestion(-53.8%)abilities of DS and reduced the microbial abundance(-27.7%)in DS guts.Compared with SH-ACs,RL-ACs showed relatively low impact on the ingestion(-3.23%),incorporation(-5.89%)and digestion(-23.9%)abilities of DS.Interestingly,ACs-SMs enhanced the ingestion(+9.68%),incorporation(+52.9%)and digestion(+51.3%)abilities of DS and increased the microbial abundance(+10.7%)in DS guts.Overall ACs and ACs-SMs reduced the diversity of microflora in DS guts.In conclusion,ACs-SMs can release ACs sustainably and prolong the sustained release time,which not only effectively reduce the toxicity of ACs,but also had positive effects on DS.

关键词： Allelochemicals(ACs) Sustained-release microspheres (SMs) Daphnia magna Straus(DS)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Temporal sequence Object-based CNN(TS-OCNN) for crop classification from fine resolution remote sensing image time-series

引用

The Crop Journal 2022年第5期10卷 1507-1516页

作者： Huapeng Li yajun tian Ce Zhang Shuqing Zhang Peter MAtkinson Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130012JilinChina Lancaster Environment Centre Lancaster UniversityLancaster LA14YQUK Faculty of Science and Technology Lancaster UniversityLancaster LA14YRUK

Accurate crop distribution mapping is required for crop yield prediction and field management. Due to rapid progress in remote sensing technology, fine spatial resolution(FSR) remotely sensed imagery now offers great opportunities for mapping crop types in great detail. However, within-class variance can hamper attempts to discriminate crop classes at fine resolutions. Multi-temporal FSR remotely sensed imagery provides a means of increasing crop classification from FSR imagery, although current methods do not exploit the available information fully. In this research, a novel Temporal Sequence Object-based Convolutional Neural Network(TS-OCNN) was proposed to classify agricultural crop type from FSR image time-series. An object-based CNN(OCNN) model was adopted in the TS-OCNN to classify images at the object level(i.e., segmented objects or crop parcels), thus, maintaining the precise boundary information of crop parcels. The combination of image time-series was first utilized as the input to the OCNN model to produce an ‘original’ or baseline classification. Then the single-date images were fed automatically into the deep learning model scene-by-scene in order of image acquisition date to increase successively the crop classification accuracy. By doing so, the joint information in the FSR multi-temporal observations and the unique individual information from the single-date images were exploited comprehensively for crop classification. The effectiveness of the proposed approach was investigated using multitemporal SAR and optical imagery, respectively, over two heterogeneous agricultural areas. The experimental results demonstrated that the newly proposed TS-OCNN approach consistently increased crop classification accuracy, and achieved the greatest accuracies(82.68% and 87.40%) in comparison with state-of-the-art benchmark methods, including the object-based CNN(OCNN)(81.63% and85.88%), object-based image analysis(OBIA)(78.21% and 84.83%), and standard pixel-wise CNN(79.18%and 82.90%). The proposed approach is

关键词： Convolutional neural network Multi-temporal imagery Object-based image analysis(OBIA) Crop classification Fine spatial resolution imagery

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Environmental,social,and economic assessment of energy utilization of crop residue in China

引用

Frontiers in Energy 2021年第2期15卷 308-319页

作者： Yueling ZHANG Junjie LI Huan LIU Guangling ZHAO yajun tian Kechang XIE Key Laboratory of Resources and Environmental System Optimization(Ministry of Education) College of Environmental Sciense and EngineeringNorth China Electic Power UniversityBeijing 102206China School Chemical and Environmental Engineering China University of Mining and TechnologyBeijng 100083China Department of Energy Conversion and Storage Technical University of DenmarkLyngby 2820Denmark National Institute of Clean and Low Carbon Energy Beijing 102211China Chinese Acadamy of Engineering Beijing 100088China

This paper aims to discuss an environmental, social, and economic analysis of energy utilization of crop residues from life cycle perspectives in China. The methodologies employed to achieve this objective are environmental life cycle assessment (E-LCA), life cycle cost (LCC), and social life cycle assessment (S-LCA). Five scenarios are developed based on the conversion technologies and final bioenergy products. The system boundaries include crop residue collection, transportation, pre-treatment, and conversion process. The replaced amounts of energy are also taken into account in the E-LCA analysis. The functional unit is defined as 1 MJ of energy produced. Eight impact categories are considered besides climate change in E-LCA. The investment capital cost and salary cost are collected and compared in the life cycle of the scenarios. Three stakeholders and several subcategories are considered in the S-LCA analysis defined by UNEP/SETAS guidelines. The results show that the energy utilization of crop residue has carbon emission factors of 0.09–0.18 kg (CO2 eq per 1 MJ), and presents a net carbon emissions reduction of 0.03–0.15 kg (CO2 eq per 1 MJ) compared with the convectional electricity or petrol, but the other impacts should be paid attention to in the biomass energy scenarios. The energy utilization of crop residues can bring economic benefit to local communities and the society, but the working conditions of local workers need to be improved in future biomass energy development.

关键词： crop residue life cycle assessment life cycle cost social life cycle assessment energy production

来源：

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

Porous carbon from vinegar lees for phenol adsorption

引用

Particuology 2012年第1期10卷 35-41页

作者： Mei Zhong Yin Wang Jian Yu yajun tian Guangwen Xu State Key Laboratory of Multi-Phase Complex Systems Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China Chemistry and Chemical Engineering Department Xinjiang University Xinjiang 830046 China

An effective technology for utilizing vinegar lees （VL）, a biomass waste generated during its production, is much needed in China due to the huge consumption of vinegar. This study investigates the preparation of porous carbon （PC） from VL, now reporting on the adsorption capability of PC in removing phenol from its aqueous solution. The preparation of PC consists of carbonization of VL in N2 and activation in CO2. The results show that the optimal activation temperature and time in CO2 for VL char carbonized at 800 ℃ were 875 ℃ and 1 h, respectively. The PC prepared was found to have large specific surface area and micropore volume, with an adsorptive capacity for phenol from its aqueous solution much higher than that of commercial coconut shell activated carbon （CSAC）. Adsorption of phenol from its aqueous solution by the VL-based PC was found to follow the isothermal Langmuir equation.

关键词： Porous carbonCarbonizationVinegar leesPhenolWaste water

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于广义Curvelet变换和相空间特征聚类的VSP波场分离方法

引用

地球物理学报 2024年第1期67卷 289-307页

作者：赵亮高静怀李振张伟田亚军西安交通大学信息与通信工程学院西安710049 海洋油气勘探国家工程研究中心西安710049

垂直地震剖面(Vertical Seismic Profiling,VSP)蕴含大量的地层地质信息,是连接地震反射数据与测井资料之间的桥梁.VSP数据分辨率高,资料丰富,包括上行波、下行波、转换波等多种类型的波场,常被用于地层反射界面标定、介质衰减参数反演... 详细信息

垂直地震剖面(Vertical Seismic Profiling,VSP)蕴含大量的地层地质信息,是连接地震反射数据与测井资料之间的桥梁.VSP数据分辨率高,资料丰富,包括上行波、下行波、转换波等多种类型的波场,常被用于地层反射界面标定、介质衰减参数反演等.其中,如何有效地分离波场是将VSP资料应用于油气勘探的关键之一.广义Curvelet变换是一种具有多尺度、多角度的相空间变换,能够进行相空间域波场特性的提取.本文聚焦于VSP波场的上下行波分离问题,提出一种基于广义Curvelet变换和相空间特征聚类方法.首先,采用广义Curvelet变换对VSP波场进行特征提取,构造融入相空间角度信息的特征数据集;然后,利用K-means聚类算法在相空间对波场特征进行分类;最后,对分类结果进行反变换,完成VSP上下行波波场的自适应分离.为了验证方法的有效性,本文将所提出的方法用于合成数据和实际VSP数据的波场分离,并与常用的基于F-K变换的波场分离方法进行对比.处理结果表明,本文方法角度分辨率高、抗噪能力强,波场分离结果的保真保幅性好,这为后续的成像与地层的特征分析提供了重要基础资料.

关键词：垂直地震剖面(VSP) 波场分离 Curvelet变换广义Curvelet变换 K-means聚类

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Approach and potential of replacing oil and natural gas with coal in China

引用

Frontiers in Energy 2020年第2期14卷 419-431页

作者： Junjie LI yajun tian Xiaohui YAN Jingdong YANG Yonggang WANG Wenqiang XU Kechang XIE School of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing 100083China National Institute of Clean-and-Low-Carbon Energy Beijing 102211China China Energy Investment Corporation Beijing 100011China Chinese Academy of Engineering Beijing 100088China Key Laboratory of Coal Science and Technology of the Ministry of Education Taiyuan University of TechnologyTaiyuan 030024China

China’s fossil energy is characterized by an abundance of coal and a relative lack of oil and natural gas.Developing a strategy in which coal can replace oil and natural gas is,therefore,a necessary and practical approach to easing the excessive external dependence on oil and natural gas.Based on the perspective of energy security,this paper proposes a technical framework for defining the substitution of oil and natural gas with coal in China.In this framework,three substitution classifications and 11 industrialized technical routes are reviewed.Then,three scenarios(namely,the cautious scenario,baseline scenario,and positive scenario)are developed to estimate the potential of this strategy for 2020 and 2030.The results indicate that oil and natural gas replaced by coal will reach 67 to 81 Mt and 8.7 to 14.3 Gm^3 in 2020 and reach 93 to 138 Mt and 32.3 to 47.3 Gm^3 in 2030,respectively.By implementing this strategy,China’s external dependence on oil,natural gas,and primary energy is expected to be curbed at approximately 70%,40%,and 20%by 2030,respectively.This paper also demonstrates how coal,as a substitute for oil and natural gas,can contribute to carbon and pollution reduction and economic cost savings.It suggests a new direction for the development of the global coal industry and provides a crucial reference for energy transformation in China and other countries with similar energy situations.

关键词： coal replacing oil and natural gas energy security external dependence energy strategy China

来源：

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

Effect of process conditions on the synthesis of carbon nanotubes by catalytic decomposition of methane

引用

China Particuology 2007年第3期5卷 213-219页

作者： Shuanglin Zhan yajun tian Yanbin Cui Hao Wu Yonggang Wang Shufeng Ye Yunfa Chen Institute of Process Engineering Chinese Academy of Sciences Beijing 100080 China Graduate University of Chinese Academy of Sciences Beijing 100049 China China University of Mining and Technology Beijing 100083 China

A new dual-composition catalyst based on Ni-Mo/MgO with high efficiency of producing carbon nanotubes （CNTs） from methane was reported recently. In the present article, with this type of catalyst, the impact of such experimental parameters as reaction temperature, reaction time, concentration of H2, flow rate ratio of CH4 to H2 on yield and graphitization were investigated, leading to the following optimal growth conditions： reaction time 60min, reaction temperature 900℃, CH4：H2 about 100：20mL/min, under which high-yield multi-walled CNTs bundles were synthesized. Raman measurement indicated that the as-synthesized product was well-graphitized, and the purity was estimated over 95% by TG-DSC analysis. In terms of the above results, an explanation of high-efficiency formation of CNTs bundles and the co-catalysis mechanism of Ni-Mo/MgO were suggested. 2007 Chinese Societv of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Carbon nanotubes Catalytic decomposition Carbon yield Graphitization degree

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

金融市场风险溢出对银行理财产品收益的效应研究

引用

财经理论研究 2024年第1期 12-25页

作者：龙林茂郑琦田亚军兰州财经大学统计学院甘肃兰州730020

随着《关于规范金融机构资产管理业务的指导意见》的正式实施,银行理财产品在债券市场与货币市场的投资比重增大,分析投资者所承担的金融市场风险溢出效应,有利于投资者对银行理财产品进行选择。本文运用溢出指数法测度债券市场与货币... 详细信息

随着《关于规范金融机构资产管理业务的指导意见》的正式实施,银行理财产品在债券市场与货币市场的投资比重增大,分析投资者所承担的金融市场风险溢出效应,有利于投资者对银行理财产品进行选择。本文运用溢出指数法测度债券市场与货币市场风险溢出对银行理财产品收益率的效应或者风险贡献,并运用GARCH模型检验溢出指数法测度的有效性,继而就《关于规范金融机构资产管理业务的指导意见》实施前后的影响进行对比分析。研究表明:债券市场对银行理财产品投资收益有相对较大的风险溢出效应,货币市场的风险溢出效应相对较小,且债券市场变化对银行理财产品投资收益的影响存在滞后效应。《关于规范金融机构资产管理业务的指导意见》实施前后,债券市场、货币市场对银行理财产品投资收益的风险溢出效应呈现前高后低。《关于规范金融机构资产管理业务的指导意见》实施后,债券市场和货币市场对银行理财产品收益的风险溢出效应并没有因投资比重增加而显著增强。未来,银行理财产品投资者承担的风险主要来源于银行的投资管理。银行需要在债券市场进一步加强投资管理,以降低银行理财产品投资者的风险。

关键词：金融市场风险溢出资管新规银行理财产品收益

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

全球综合地磁场模型精度评估及统计特征分析

引用

测绘与空间地理信息 2024年第1期47卷 20-23,28页

作者：赵俊田源张亚军西安测绘总站陕西西安710054 大地测量与地球动力学国家重点实验室湖北武汉430077

随着全球地磁场模型的不断更新,利用相关数据开展精度评估及统计特征分析,对于精准评价地磁场模型的可靠性,具有十分重要的意义。结合国际地磁台网(Intermagnet)150个台站,分析了3个(POMME-11,CHAOS-7,EMM2017)全球综合地磁场模型在全... 详细信息

随着全球地磁场模型的不断更新,利用相关数据开展精度评估及统计特征分析,对于精准评价地磁场模型的可靠性,具有十分重要的意义。结合国际地磁台网(Intermagnet)150个台站,分析了3个(POMME-11,CHAOS-7,EMM2017)全球综合地磁场模型在全球范围内的平均精度,得到了7个地磁分量的相关精度指标,从地磁台站数据比较的数值结果来看,EMM2017整体三精度相对较优,CHAOS-7次之,POMM11最差。其中EMM2017三分量(X,Y,Z)及总强度的精度分别为75.98 nT,104.38 nT,113.07 nT,101.71 nT,相对精度比CHAOS-7提升21.69%,5.45%,21.25%,24.94%,因此,在地学研究及地磁场应用方面,应优先采用EMM2017模型。同时基于功率普、系数相关性、敏感性矩阵3个方面对模型系数进行了统计特征分析,在功率普方面EMM2017均优于其他两个模型,而在系数相关性、敏感性矩阵方面CHAOS-7与CM6相似。

关键词：地磁场模型 Intermagnet 精度评估统计特征分析

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

中国现代能源体系建设进程评估

引用

工程科学与技术 2024年第1期56卷 206-217页

作者：朱广岩张小妹严晓辉高丹呼和涛力程婉静田亚峻谢克昌中国科学院青岛生物能源与过程研究所泛能源大数据与战略研究中心山东青岛266101 山东能源研究院山东青岛266101 青岛新能源山东省实验室山东青岛266101 中国科学院大学化学工程学院北京100049 国家能源投资集团有限责任公司科技部北京100013 华北电力大学能源动力与机械工程学院北京102206 常州大学城乡矿山研究院江苏常州213164 中国社会科学院数量经济与技术经济研究所北京100732 中国工程院北京100088

能源是国家经济社会发展的基石,构建现代能源体系对保障国家能源安全,如期实现“双碳”目标,推动经济社会高质量发展具有重要意义。本文基于清洁、低碳、安全、高效4个维度构建了现代能源指标体系,运用序关系分析法定量评价中国现代能... 详细信息

能源是国家经济社会发展的基石,构建现代能源体系对保障国家能源安全,如期实现“双碳”目标,推动经济社会高质量发展具有重要意义。本文基于清洁、低碳、安全、高效4个维度构建了现代能源指标体系,运用序关系分析法定量评价中国现代能源体系的历史进程,并进行国内外横向对比。结果表明:过去11年(2010—2020年),中国推动能源革命进程成效显著,2020年达到了世界平均水平,在全球76个主要经济体中排名第38位,落后于欧盟、美国、日本等发达经济体,领先于俄罗斯、印度等发展中经济体。中国高效指数排名明显落后于发达经济体,表明中国能效提升方面空间巨大,也说明更要重视科技投入;中国的安全指数排名比较靠前,证明了中国煤炭在能源安全中的“压舱石”地位,但是同样的原因导致中国的低碳指数相对落后;过去10年,中国能源清洁利用成效显著,但是排名整体靠后,说明中国能源的清洁开发利用依然任重道远。其中,中国能源结构指标、碳排放系列指标、能源强度指标是影响中国综合指数水平的关键性指标,尤其是能源强度指标。因此,首先,未来要加快构建以可再生能源为主、以化石能源为辅的现代能源体系;其次,新能源与低碳技术达到体量尚需时日,长期以来,煤炭支撑中国经济和社会较快发展,是中国能源安全保障的压舱石和稳定器,煤炭清洁高效利用仍需加强,而实现了清洁高效利用的煤炭就是能源清洁;最后,能源转型的关键是优化能源结构,要多能互补,集成热、电、气、冷,提升火电机组灵活性,而在终端消费方面提高能源效率,降低能源强度,实施电能替代,形成以电为中心的能源消费格局。

关键词：现代能源体系指数清洁低碳安全高效

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：