期刊文献+
共找到1,596篇文章
< 1 2 80 >
每页显示 20 50 100
Research on the Transfer Benefit of Railway Investment Projects
1
作者 Yang Jimei Xie Wei(School of Economics and Management,Southwest Jiaotong University,Chengdu 610031,China) 《Journal of Modern Transportation》 1995年第1期16-23,共8页
Though an additional railway investment will result in very complex uifluenceon the whole economic-socinl system, an assessing system comes to be set up inthis thesis. It not only shows the seope and direction of the ... Though an additional railway investment will result in very complex uifluenceon the whole economic-socinl system, an assessing system comes to be set up inthis thesis. It not only shows the seope and direction of the assessment ofrailway investment projects, but indicates a new assessment theory coming intobeins. lii view of the transfer benefit of railway investinent projects being themain part of their external benefit for our national economy, we paid specialattention to calculating the transfer benefit. Finally, a series of matheniaticalmodels throush which we can accurately figure out the transfer benefit of arailway investment project are presented. 展开更多
关键词 assessing system the transfer benefit
下载PDF
Eco-environmental benefit assessment of China's South-North Water Transfer Scheme——the middle route project
2
作者 DUANGuang-ming ZHAOJing-zhu LIUGuo-hua KEBing XIAOHan WUGang DENGHong-bing 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第2期308-315,共8页
This paper assess the eco-environmental benefits that may come from the middle route project of China's South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of ... This paper assess the eco-environmental benefits that may come from the middle route project of China's South-North Water Transfer Scheme(SNWT) with principles and methods of eco-economics and planning reports of SNWT's middle route project. Some benefits were calculated in monetary units. To make sure that the results can be comparable with normal monetary indices, concrete assessment objects and the parameters are prudently selected according to the major characteristics of the project and its water import region. Primary assessment revealed that in different project construction stages, the benefit could be more than 13 07 billion RMB Yuan in 2010 and 19 79 billion RMB Yuan in 2030, respectively. The monetary value tends to increase with social-economic development. To realize these potential benefits, however, calls for more endeavors. 展开更多
关键词 China's South-North Water transfer Scheme(SNWT) the middle route project of South-North Water transfer(MRPSNWT) assessment ecosystem services monetary indices
下载PDF
Analysis of Patterns and Benefits of Cultivated Land Transfer in Rural Areas in the Loess Plateau——A Case Study of Yuanzhou District of Ningxia
3
作者 Xiaoyi SUN Yong XU Qing TANG 《Asian Agricultural Research》 2016年第10期59-65,共7页
Cultivated land transfer is one of hotspots in research on agriculture,rural areas and farmers in China. Based on research achievements related to cultivated land transfer and the field survey of Yuanzhou District in ... Cultivated land transfer is one of hotspots in research on agriculture,rural areas and farmers in China. Based on research achievements related to cultivated land transfer and the field survey of Yuanzhou District in the Loess Plateau,the primary patterns of cultivated land transfer in rural areas in the Loess Plateau were summarized according to the management subjects of cultivated land. According to the analyses of family income and expenses of a peasant household,the benefit of various patterns of cultivated land transfer to increase farmers' income was analyzed,and the social and ecological benefits of cultivated land transfer were assessed. The results showed that cultivated land transfer had developed rapidly in the Loess Plateau,and 42. 5% of the investigated peasant households took part in cultivated land transfer. The benefit of cultivated land transfer to increase farmers' income was obvious after cultivated land transfer. There were significant differences between various patterns of cultivated land transfer in the increase of farmers' income. The pattern driven by agricultural cooperatives increased farmers' income most obviously,and the annual family earnings per peasant household reached 12072. 99 yuan / a. The social and ecological benefits of cultivated land transfer conducted by peasant households spontaneously were very remarkable. The pattern led by leading enterprises promoted the large-scale operation of cultivated land greatly,but its benefit to increase farmers' income was limited. The comprehensive benefit of the pattern guided by the government was the most balanced. Geographic environment had decisive influences on the choose of patterns of cultivated land transfer in the Loess Plateau. 展开更多
关键词 Loess Plateau Cultivated land transfer PATTERNS benefit Yuanzhou District of Ningxia
下载PDF
Ecosystem service value of artificial reef area in Qingdao Luhaifeng sea ranching:A meta-analysis and benefit transfer valuation
4
作者 LIU Ya-jun Paula NOVO 《Ecological Economy》 2022年第4期261-273,共13页
This study evaluates the ecosystem service value of Qingdao Luhaifeng Sea Ranch artificial reef area through the established meta-analysis value transfer model,and the results show that the total value will be 150 mil... This study evaluates the ecosystem service value of Qingdao Luhaifeng Sea Ranch artificial reef area through the established meta-analysis value transfer model,and the results show that the total value will be 150 million yuan in 2022.According to the regression results of the meta-analysis,the types of ecosystem services,the types of pasture sediment,the population density of the pasture area,and the economic level all have a significant impact on the wetland value.The model in this paper passes the validity test,and the conclusions are the same as many current empirical studies.This shows that the benefit transfer method meta-analysis can save assessment labor,time and capital,and the decision-makers can make judgments quickly.Meta-analysis is an effective and fast ex ante evaluation tool.The reliability of the value transfer method of meta-analysis largely depends on the quantity and quality of existing studies and the establishment of mathematical models.It is necessary to expand the number of literature searches.However,the current evaluation method of ecosystem services in China has just started,so the government needs to encourage research institutions to evaluate the value of ecosystem services to provide more effective and abundant research literature. 展开更多
关键词 sea ranching artificial reef ecosystem services benefit transfer META-ANALYSIS
下载PDF
Cyberattack Ramifications, The Hidden Cost of a Security Breach
5
作者 Meysam Tahmasebi 《Journal of Information Security》 2024年第2期87-105,共19页
In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term ... In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term consequences that businesses encounter. This study integrates findings from various research, including quantitative reports, drawing upon real-world incidents faced by both small and large enterprises. This investigation emphasizes the profound intangible costs, such as trade name devaluation and potential damage to brand reputation, which can persist long after the breach. By collating insights from industry experts and a myriad of research, the study provides a comprehensive perspective on the profound, multi-dimensional impacts of cybersecurity incidents. The overarching aim is to underscore the often-underestimated scope and depth of these breaches, emphasizing the entire timeline post-incident and the urgent need for fortified preventative and reactive measures in the digital domain. 展开更多
关键词 Artificial Intelligence (AI) Business Continuity Case Studies Copyright Cost-benefit Analysis Credit Rating Cyberwarfare Cybersecurity Breaches Data Breaches Denial Of Service (DOS) Devaluation Of Trade Name Disaster Recovery Distributed Denial of Service (DDOS) Identity theft Increased Cost to Raise Debt Insurance Premium Intellectual Property Operational Disruption Patent Post-Breach Customer Protection Recovery Point Objective (RPO) Recovery Time Objective (RTO) Regulatory Compliance Risk Assessment Service Level Agreement Stuxnet Trade Secret
下载PDF
Need for operational simplicity and timely disbursal of benefits—a qualitative exploration of the implementation of a direct benefit transfer scheme for persons with tuberculosis in India
6
作者 Malu Mohan Jeromie W.V.Thangaraj +17 位作者 Sumit Pandey G.Sri Lakshmi Priya Sivavallinathan Arunachalam Rahul Sharma Hemant Deepak Shewade B.Aishwarya K.Afeeq Afsana Khatoon B.Gokulvijay Gude Sireesha Kavita Chandra S.Nandhakumar Prince Samuel C.Nanditha Viswanathan Devika Shanmugasundaram Raghuram Rao Manoj V.Murhekar Kathiresan Jeyashree 《Infectious Diseases of Poverty》 SCIE CAS CSCD 2024年第3期58-72,共15页
Background Ni-kshay Poshan Yojana(NPY)is a direct benefit transfer scheme of the Government of India introduced in 2018 to support the additional nutritional requirements of persons with TB(PwTB).Our recent nationwide... Background Ni-kshay Poshan Yojana(NPY)is a direct benefit transfer scheme of the Government of India introduced in 2018 to support the additional nutritional requirements of persons with TB(PwTB).Our recent nationwide evaluation of implementation and utilization of NPY using programmatic data of PwTB from nine randomly selected Indian states,reported a 70%coverage and high median delay in benefit credit.We undertook a qualitative study between January and July 2023,to understand the detailed implementation process of NPY and explore the enablers and barriers to effective implementation and utilization of the NPY scheme.Methods We followed a grounded theory approach to inductively develop theoretical explanations for social phenomena through data generated from multiple sources.We conducted 36 in-depth interviews of national,district and field-level staff of the National Tuberculosis Elimination Programme(NTEP)and NPY beneficiaries from 30 districts across nine states of India,selected using theoretical sampling.An analytical framework developed through inductive coding of a set of six interviews,guided the coding of the subsequent interviews.Categories and themes emerged through constant comparison and the data collection continued until theoretical saturation.Results Stakeholders perceived NPY as a beneficial initiative.Strong political commitment from the state administration,mainstreaming of NTEP work with the district public healthcare delivery system,availability of good geographic and internet connectivity and state-specific grievance redressal mechanisms and innovations were identified as enablers of implementation.However,the complex,multi-level benefit approval process,difficulties in accessing banking services,perceived inadequacy of benefits and overworked human resources in the NTEP were identified as barriers to implementation and utilization.Conclusion The optimal utilization of NPY is enabled by strong political commitment and challenged by its lengthy implementation process and delayed disbursal of benefits.We recommend greater operational simplicity in NPY implementation,integrating NTEP activities with the public health system to reduce the burden on the program staff,and revising the benefit amount more equitably. 展开更多
关键词 National Tuberculosis Elimination Programme Nutritional status Direct benefit transfer IMPLEMENTATION Cash transfer scheme Grounded theory INDIA
原文传递
The Benefit Risk Assessment of Consumption of Marine Species Based on Benefit-Risk Analysis for Foods(BRAFO)-tiered Approach 被引量:5
7
作者 GAO Yi Xiong ZHANG Hong Xia +6 位作者 LI Jing Guang ZHANG Lei YU Xin Wei HE Jia Lu SHANG Xiao Hong ZHAO Yun Feng WU Yong Ning 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2015年第4期243-252,共10页
Objective To assess the net health effect caused by the consumption of specific marine species based on Benefit-Risk Analysis for Foods (BRAFO)-tiered approach. Methods Twenty species were collected from the Zhousha... Objective To assess the net health effect caused by the consumption of specific marine species based on Benefit-Risk Analysis for Foods (BRAFO)-tiered approach. Methods Twenty species were collected from the Zhoushan Archipelago, China. Concentrations of n-3 long-chain polyunsaturated fatty acids, methyl mercury (MeHg), and dioxin-like compounds (DLCs) in the samples were analyzed for benefit risk assessment based on BRAFO-tiered approach. Results Based on the BRAFO-tiered approach, reference scenario (no intake) and alternative scenario (intake of specific species of 200 g/week) were determined. The exposure to MeHg/DLCs via alternative scenario of all studied species did not exceed provisional tolerable weekly/monthly intake. However, the adult population with high DLCs exposure in China would significantly exceed the upper limit of DLCs via an additional alternative scenario of some species such as Auxis thazard. The results of deterministic computation showed that alternative scenario of all studied species generated clear net beneficial effects on death prevention and child IQ gain. Conclusion The alternative scenario of all studied species could be recommended to population with average DLCs exposure, and the reference scenario of species with relatively high DLCs concentration could be recommended to population exposed to high DLCs. 展开更多
关键词 N-3 long-chain polyunsaturated fatty acid Methyl mercury Dioxin-like compound benefit-Risk Analysis for Foods (BRAFO) benefit risk assessment
下载PDF
Spatial distribution prediction and benefits assessment of green manure in the Pinggu District,Beijing,based on the CLUE-S model 被引量:14
8
作者 ZHANG Li-ping ZHANG Shi-wen +3 位作者 ZHOU Zhi-ming HOU Sen HUANG Yuan-fang CAO Wei-dong 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2016年第2期465-474,共10页
Green manure use in China has declined rapidly since the 1980 s with the extensive use of chemical fertilizers.The deterioration of field environments and the demand for green agricultural products have resulted in mo... Green manure use in China has declined rapidly since the 1980 s with the extensive use of chemical fertilizers.The deterioration of field environments and the demand for green agricultural products have resulted in more attention to green manure.Human intervention and policy-oriented behaviors likely have large impacts on promoting green manure planting.However,little information is available regarding on where,at what rates,and in which ways(i.e.,intercropping green manure in orchards or rotating green manure in cropland) to develop green manure and what benefits could be gained by incorporating green manure in fields at the county scale.This paper presents the conversion of land use and its effects at small region extent(CLUE-S) model,which is specifically developed for the simulation of land use changes originally,to predict spatial distribution of green manure in cropland and orchards in 2020 in Pinggu District located in Beijing,China.Four types of land use for planting or not planting green manure were classified and the future land use dynamics(mainly croplands and orchards) were considered in the prediction.Two scenarios were used to predict the spatial distribution of green manure based on data from 2011:The promotion of green manure planting in orchards(scenario 1) and the promotion of simultaneous green manure planting in orchards and croplands(scenario 2).The predictions were generally accurate based on the receiver operating characteristic(ROC) and Kappa indices,which validated the effectiveness of the CLUE-S model in the prediction.In addition,the spatial distribution of the green manure was acquired,which indicated that green manure mainly located in the orchards of the middle and southern regions of Dahuashan,the western and southern regions of Wangxinzhuang,the middle region of Shandongzhuang,the eastern region of Pinggu and the middle region of Xiagezhuang under scenario 1.Green manure planting under scenario 2 occurred in orchards in the middle region of Wangxinzhuang,and croplands in most regions of Daxingzhuang,southern Pinggu,northern Xiagezhuang and most of Mafang.The spatially explicit results allowed for the assessment of the benefits of these changes based on different economic and ecological indicators.The economic and ecological gains of scenarios 1 and 2 were 175691 900 and143000 300 CNY,respectively,which indicated that the first scenario was more beneficial for promoting the same area of green manure.These results can facilitate policies of promoting green manure and guide the extensive use of green manure in local agricultural production in suitable ways. 展开更多
关键词 CLUE-S model green manure spatial distribution prediction benefits assessment
下载PDF
Benefit evaluation of the Three-Gorges Reservoir migration by an assessment index model based on analytic hierarchy process 被引量:1
9
作者 WANG Jun-hui GAN Lian-jun 《Journal of Chongqing University》 CAS 2007年第2期100-106,共7页
An assessment index model was established to evaulate the benefit of the Three-Gorges Reservoir migration through the analytical hierarchy process. Totally 43 indicators were selected to assess the impact of migration... An assessment index model was established to evaulate the benefit of the Three-Gorges Reservoir migration through the analytical hierarchy process. Totally 43 indicators were selected to assess the impact of migration on the economic, social and ecological environmental aspects of the migration communities, with the data of the indicators of the years 1992, 1998, 2002 which represented the period of premigration, the end of the first phase migration and the end of the second phase migration, respectively. The evaluation matrix is sufficiently consistent, with a consistency ratio CR equal to 0.086 3. The assessment turned out a benefit value for the economic subsystem in the year 2004 larger than triple the value in the year 1992, indicating a remarkable economic growth in the Reservoir area. The constantly increasing value for the social subsystem reflects the stable social situations. There is a slight decline in the assessment outcome of the ecological subsystem for the year 1998, which implies enviromental conservation was given insufficient importance during that period. On the whole, the implementation of the migration project is favorable to the Reservoir region, as confirmed by the stably increasing overall evaluation value from 42.22% in 1992 to 68.81% in 2002. However, there is still much room to improve from the status quo to the target criteria. 展开更多
关键词 Three-Gorges Reservoir migration benefit index system comprehensive assessment
下载PDF
Comprehensive benefits assessment of the ecological management model in Hobq Desert of China
10
作者 Rui Wang Li Hua Zhou Yong Chen 《Research in Cold and Arid Regions》 CSCD 2018年第3期251-260,共10页
The Hobq Desert is the seventh largest desert in China. Since 1988, the effects of ecological management in Hobq Desert have been obvious and a typical desertification control model developed gradually, which is well ... The Hobq Desert is the seventh largest desert in China. Since 1988, the effects of ecological management in Hobq Desert have been obvious and a typical desertification control model developed gradually, which is well known as the "Hobq model". It is important to evaluate the comprehensive benefits of the "Hobq model", but this has not been addressed in previous studies. Thus, we established an index system to comprehensively evaluate the benefits of the "Hobq model", using an analytic hierarchy process method from 1988 to 2013. The results show the following: ecological benefits of the "Hobq model" had a positive trend, but with fluctuations during 2008 and 2009; economic benefits increased by 74% and the maximum value occurred in 2013; and social benefits increased steadily, but with fluctuations in 2010 and 2011. The social benefits were higher than ecological and economic benefits in the same period. Trends in overall benefits of the "Hobq model" were similar to changes in ecological benefits, which increased each year. 展开更多
关键词 benefit assessment comprehensive benefit ecological management Hobq model
下载PDF
Study on Assessment of the Disastrous Weather Warning Service Benefit
11
作者 JI Li GOU Si LI Guang-bing 《Meteorological and Environmental Research》 2012年第1期79-81,共3页
Assessment of the disastrous weather warning service benefit has important guidance significance for improving meteorological forecast capability and meteorological service level. Meanwhile, it is also weak link of th... Assessment of the disastrous weather warning service benefit has important guidance significance for improving meteorological forecast capability and meteorological service level. Meanwhile, it is also weak link of the current meteorological work. Took Beibei District of Chongqing as an example, by analyzing issuance of the rainstorm warning signal from 2008 to now, its disastrous weather warning service benefit was evaluated. Result showed that assessment of the disastrous weather warning service benefit should be studied from forecast accuracy, forecast timeliness, forecast coverage and disaster prevention capability. 展开更多
关键词 Disastrous weather warning Service benefit ASSESSMENT China
下载PDF
A New Criteria to Apply Weight-Dependent CATSthr to Cost-Benefit Analysis within the Framework of IMO EnvironmentaI-FSA Studies
12
作者 Y. Yamada F. Kaneko 《Journal of Shipping and Ocean Engineering》 2011年第1期65-76,共12页
The purpose of this paper is to investigate reasonable cost benefit criteria within the framework of environmental formal safety assessment (FSA). In this study a statistical analysis of oil spill data was carried o... The purpose of this paper is to investigate reasonable cost benefit criteria within the framework of environmental formal safety assessment (FSA). In this study a statistical analysis of oil spill data was carried out based on the report of International Oil Pollution Compensation Funds. According to the statistical study of actual oil spill from tankers, it is found that collisions and groundings are the most probable causes of the oil spills from tankers. Probability distributions of costs of oil spill and oil spill amount are investigated, and a non-linear regression formula between costs of oil spills and oil spill weight are derived. Using the regression formula, an oil spill weight dependent CATStm (Cost of Averting a Ton of oil Spilt) is proposed. Moreover in order to apply the weight dependent CATSthr to cost benefit analysis (CBA), a new cost-effective criterion is newly proposed with considering its concrete application to environmental FSA. 展开更多
关键词 Cost of oil spill formal safety assessment cost benefit analysis CAF CATS.
下载PDF
长距离调水工程安全风险综合评估 被引量:1
13
作者 胡江 叶伟 马福恒 《南水北调与水利科技(中英文)》 CAS CSCD 北大核心 2024年第3期417-426,共10页
以某跨流域、跨多省市的长距离调水工程为例,分析工程安全面临的各类风险事件,确定两座节制闸之间的运行调度渠段为风险评估单元,发展基于层次分析法的风险综合评估模型;以一梁式输水渡槽为例,阐释建筑物风险因子识别、风险事件分析和... 以某跨流域、跨多省市的长距离调水工程为例,分析工程安全面临的各类风险事件,确定两座节制闸之间的运行调度渠段为风险评估单元,发展基于层次分析法的风险综合评估模型;以一梁式输水渡槽为例,阐释建筑物风险因子识别、风险事件分析和风险等级标准划分的方法,描述风险评估过程;以该渡槽所在的运行调度渠段为评估单元,采用层次分析法进行风险综合评估;在此基础上,对其余运行调度渠段进行风险综合评估,讨论造成较大风险的主要原因。结果表明:提出的方法辨识出了较大风险的运行调度渠段,造成运行调度渠段工程安全风险综合评估结果为较大风险的因素可归结为左岸水库溃坝或超调水工程防洪标准泄洪导致的风险、交叉河道过流能力不足风险以及左排下游通道排水不畅风险等,进而有针对性地提出了风险管控措施。研究结果可为类似长距离调水工程安全风险综合评估和管控提供参考。 展开更多
关键词 调水工程 风险评估 工程安全 层次分析法 风险管控
下载PDF
论注册资本认缴制的兴利除弊:兼论期限利益与交易安全的动态平衡 被引量:3
14
作者 刘俊海 《学术论坛》 CSSCI 北大核心 2024年第1期44-59,共16页
肇端于2005年《公司法》的注册资本认缴制改革具有正当性与合理性。认缴制的核心是创设了股东延期实缴出资的期限利益,尊重与保护期限利益是一般原则,出资义务加速到期是例外规则。股东期限利益的得丧变更均不妨碍股权的自由转让。认缴... 肇端于2005年《公司法》的注册资本认缴制改革具有正当性与合理性。认缴制的核心是创设了股东延期实缴出资的期限利益,尊重与保护期限利益是一般原则,出资义务加速到期是例外规则。股东期限利益的得丧变更均不妨碍股权的自由转让。认缴制未根本否定资本制度,一旦公司丧失偿债能力,期限利益立即终止,出资义务加速到来。公司不能清偿到期债务的识别标准是执行失败主义,出资加速到期不以股东或公司存在主观过错为要件。有必要建立股东加速出资信息公示制度与敦促债权人及时申报债权的公示催告程序,以确保债权人平等保护。不少判例追究股东恶意转让未实缴出资股权时对公司债权人的赔偿责任,建议以2023年新修订的《中华人民共和国公司法》为基础,完善平衡对冲制度,兼顾公司资本信用与股权流转自由,细化股权转让链条中出资义务加速到期的责任在前后手之间的配置规则。信息披露、5年最长实缴出资期限与出资加速到期连带之债的良性互动,有助于遏制注册资本认缴制的道德风险外溢。 展开更多
关键词 注册资本认缴制 期限利益 加速到期 股权转让 债权人 连带之债
下载PDF
南水北调东线一期工程受水区生态环境效益演变 被引量:1
15
作者 高媛媛 杨亚锋 +2 位作者 杨荣雪 刘艺欣 王红瑞 《南水北调与水利科技(中英文)》 CAS CSCD 北大核心 2024年第3期566-574,共9页
研究南水北调东线一期工程通水以来受水区生态环境效益的演变态势,对南水北调后续工程高质量建设、加快构建国家水网以及促进工程综合效益发挥有决策参考作用。以定性定量相结合的方式分析东线一期工程在优化水资源配置、保障饮水安全... 研究南水北调东线一期工程通水以来受水区生态环境效益的演变态势,对南水北调后续工程高质量建设、加快构建国家水网以及促进工程综合效益发挥有决策参考作用。以定性定量相结合的方式分析东线一期工程在优化水资源配置、保障饮水安全、复苏河湖生态环境和畅通南北经济循环等方面的作用,进而结合层次分析法,从直接效益和间接效益2个方面,筛选构建东线一期工程受水区生态环境效益评价指标体系,主要包括工程年供水量、水质改善度、生态补水量、地下水压采量、地下水水位、水域面积、绿地面积和涵养水源等,并采用VlseKriterijumska Optimizacija I Kompromisno Resenje(VIKOR)多准则妥协解排序方法对南水北调东线一期工程通水以来即2013-2022年受水区生态环境效益演变态势进行分析。结果表明:南水北调东线一期工程通水的10年以来,受水区的生态环境整体复苏效果明显,近3年排序值保持在0.8以上;受降水偏枯进而影响地下水开采量和地下水水位等因素影响,2019年间接生态环境效益下降29.2%,之后迅速恢复并保持稳定。在分析直接效益和间接效益演变的基础上,从工程提质增效、提高工程水质状况以及完善体制机制建设等方面提出东线一期工程进一步促进受水区生态环境持续改善的策略和建议,以期为东线工程及受水区生态环境保护及高质量发展相关研究、决策制定等提供参考。 展开更多
关键词 南水北调东线一期工程 生态环境效益 指标体系 VIKOR
下载PDF
江苏水稻种植方式碳足迹和经济效益综合评价
16
作者 季国军 纪洪亭 +6 位作者 程琨 刘满强 江瑜 胡正锟 张岳芳 胡乃娟 胡锋 《土壤学报》 CAS CSCD 北大核心 2024年第4期1042-1054,共13页
系统分析水稻不同种植方式碳足迹及经济效益对水稻生产碳减排和发展低碳农业具有重要意义,目前在省级尺度上关于不同水稻种植方式碳足迹和经济效益综合评价的研究尚少见报道。基于江苏水稻农情调查数据,利用生命周期评价方法定量分析江... 系统分析水稻不同种植方式碳足迹及经济效益对水稻生产碳减排和发展低碳农业具有重要意义,目前在省级尺度上关于不同水稻种植方式碳足迹和经济效益综合评价的研究尚少见报道。基于江苏水稻农情调查数据,利用生命周期评价方法定量分析江苏水稻不同种植方式碳足迹及经济效益。结果表明,2016-2020年不同水稻种植方式单位面积碳足迹为11.28~14.39t·hm^(-2),单位产量碳足迹为1.30~1.52kg·kg^(-1),单位产值碳排放为0.49~0.58kg·yuan^(-1),单位面积碳足迹、单位产量碳足迹和单位产值碳足迹从大到小依次为抛秧水稻或手插水稻、机插水稻、直播水稻。机插水稻和手插水稻生产单位面积碳足迹随年份的增加呈下降趋势。机插水稻、手插水稻和直播水稻单位产量碳足迹随年份的变化呈下降趋势。不同水稻生产种植方式碳足迹中占比最大的是稻田甲烷排放,其次为氮肥施用导致的碳足迹、稻田氧化亚氮排放和灌溉用电导致的碳足迹。氮肥和灌溉用电是影响不同水稻种植方式碳足迹差异的主要驱动因素。不同水稻种植方式总收益为2.51×10^(3)~2.75×10^(3)yuan·hm^(-2),资源投入成本为1.88×10^(3)~1.99×10^(3)yuan·hm^(-2),碳排放成本为0.20×10^(3)~0.25×10^(3)yuan·hm^(-2),考虑碳排放的净收益(NI-CO_(2))为0.39×10^(3)~0.64×10^(3) yuan·hm^(-2)。机插水稻NI-CO_(2)低于其他三种水稻种植方式,这与机插水稻较高的总收益和较低的资源投入成本和较低的碳排放成本有关。综上所述,仅考虑碳排放,直播水稻是最为低碳的水稻种植方式,综合碳排放和经济效益,机插水稻优于手插、直播和抛秧水稻。 展开更多
关键词 水稻 种植方式 碳足迹 经济效益 生命周期评价
下载PDF
体系化构造:美国保密基础设施立法及启示 被引量:1
17
作者 张涛 朱莉欣 《西安交通大学学报(社会科学版)》 CSSCI 北大核心 2024年第4期144-154,共11页
数字技术高速发展态势下,国家保密法律制度需要树立符合时代特征的保密基础设施概念,充分考虑设置、维护、管理和销毁保密信息的端点、系统环境、人员的安全及相应的能力,以积极应对网络信息技术运用带来的环境变化和挑战。第二次世界... 数字技术高速发展态势下,国家保密法律制度需要树立符合时代特征的保密基础设施概念,充分考虑设置、维护、管理和销毁保密信息的端点、系统环境、人员的安全及相应的能力,以积极应对网络信息技术运用带来的环境变化和挑战。第二次世界大战后美国保密立法历程表明,美国通过法律法规推动保密基础设施的现代化和改革,逐步完成了系统架构下的涉密信息安全保障;而立法后紧跟的标准、手册等规范文件对贯彻实施其保密基础设施法律法规也起到了非常重要的作用。美国保密基础设施立法一直以国家安全战略为遵循,并不断加强与企业合作,如今则更加重视与网络安全的衔接。研究美国保密基础设施立法现状与趋势,为中国从立法理念、规范内容和形式等方面完善保密法律制度提供了新思路。 展开更多
关键词 国家安全 网络安全 保密基础设施 保密法律制度 关键基础设施 受控非密信息系统 权益让渡
下载PDF
一种基于深度自适应网络迁移的暂稳评估模型更新框架
18
作者 李楠 张帅 +1 位作者 胡禹先 隋想 《电力系统保护与控制》 EI CSCD 北大核心 2024年第14期25-35,共11页
为解决电力系统的运行方式或拓扑结构变化后暂稳评估模型的适应性问题,常规的特征迁移学习方法主要侧重于拉近源域与目标域数据集间的条件分布或边缘分布的距离,却不能定量的评价这两种分布对于不同域之间的贡献,导致模型迁移性能不理... 为解决电力系统的运行方式或拓扑结构变化后暂稳评估模型的适应性问题,常规的特征迁移学习方法主要侧重于拉近源域与目标域数据集间的条件分布或边缘分布的距离,却不能定量的评价这两种分布对于不同域之间的贡献,导致模型迁移性能不理想。针对该问题,引入SENet注意力机制和动态分布自适应算法,构建了基于SEDDAN迁移的深度自适应网络暂稳评估模型更新框架,从特征提取和不同域间分布权重的动态调整两个层面进行改进,进一步提升了评估模型的迁移性能和自适应性。在IEEE 39和IEEE 140节点系统上进行测试,仿真结果表明所提模型在更新后的评估准确性、适应性和迁移性能方面有一定的优势。 展开更多
关键词 电力系统 评估 迁移学习 注意力机制 动态自适应分布
下载PDF
放射性核素生态运移与辐射剂量评价研究现状及趋势
19
作者 刘森林 吴仁杰 +1 位作者 张欣钰 李金凤 《原子能科学技术》 EI CAS CSCD 北大核心 2024年第10期1989-2007,共19页
放射性核素在生态环境中的输运和转移(简称运移)长期以来受到辐射环境保护领域的特别关注。本文将系统梳理放射性核素在生态环境中的运移机制和模型及参数、人类和非人类生物剂量评价方法,以及在核设施发生事故情况下放射性核素非平衡... 放射性核素在生态环境中的输运和转移(简称运移)长期以来受到辐射环境保护领域的特别关注。本文将系统梳理放射性核素在生态环境中的运移机制和模型及参数、人类和非人类生物剂量评价方法,以及在核设施发生事故情况下放射性核素非平衡态运移模型及参数等相关研究现状,并从计算模型、评价方法和参数等多维度探讨放射性核素在生态环境中的运移行为,重点针对放射性核素海洋运移、非人类物种剂量评价、短期事故排放的动态模型、人工智能技术应用等方面开展进一步研究并提出建议,为核与辐射应急响应、环境监测与风险评估等提供科学依据和技术支持。 展开更多
关键词 放射性核素运移 剂量评价 非平衡态运移模型 ^(14)C
下载PDF
京郊有机作物种植的经济效益与环境影响
20
作者 乔玉辉 李强 +2 位作者 甄华杨 冯旭 张宝贵 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第11期1940-1953,共14页
随着城市居民对食品安全和环境保护的日益关注,都市型有机种植业近年来得到了快速发展。明确都市型有机种植业发展现状、经济效益和环境影响,对有机种植业可持续发展具有重要意义。本研究以北京市有机种植业(水果、蔬菜、薯类及薯芋类... 随着城市居民对食品安全和环境保护的日益关注,都市型有机种植业近年来得到了快速发展。明确都市型有机种植业发展现状、经济效益和环境影响,对有机种植业可持续发展具有重要意义。本研究以北京市有机种植业(水果、蔬菜、薯类及薯芋类、坚果和谷物)为研究对象,基于农场调研数据,采用成本效益分析和生命周期评价(LCA)方法,分别分析了有机作物生产的经济效益及其环境影响。本研究结果表明,相比常规种植,5种作物的有机种植降低了农作物的产量。不同作物之间的经济与环境表现存在较大差异。有机生产成本投入较高,尽管有机种植增加了作物利润,但是其成本利润率却低于其对应的常规对照。相比常规种植,有机种植降低了环境影响水平(LCA标准化结果),各作物的减少幅度依次为谷物>薯类及薯芋类>水果>蔬菜=坚果。考虑到粮食安全(常规种植与有机种植的产量差)、消费者负担能力(常规种植与有机种植的价格差)以及有机生产减少环境影响的幅度(常规种植与有机种植的LCA标准化结果差),政府应对有机谷物生产加大补贴力度。北京市有机种植业仍具有较大发展潜力,政府应针对有机农业制定相应补偿政策,从而激励有机农业的进一步发展。 展开更多
关键词 有机农业 都市农业 生命周期评价 环境影响 经济效益
下载PDF
上一页 1 2 80 下一页 到第
使用帮助 返回顶部