Cropland suitability analysis is a vital tool for ensuring food security and sustainable agriculture,coordinating ecological space with human activity space on the Qinghai-Tibet Plateau(QTP).However,there are few stud...Cropland suitability analysis is a vital tool for ensuring food security and sustainable agriculture,coordinating ecological space with human activity space on the Qinghai-Tibet Plateau(QTP).However,there are few studies on complete and accurate cropland suitability assessments on the QTP,let alone on identifying key potential areas for cropland development.We used a novel assessment model to generate a 30-m cropland suitability map for the QTP.The identification of areas with cropland development potential and the evaluation of potentially available cropland were further integrated into a unified analytical framework.We found that only 10.18%of the study area is suitable for large-scale and permanent cropland.Moreover,approximately 72.75%of the existing cropland was found to be distributed in suitable or marginally suitable areas.Considering the trade-offs related to irrigation water supply convenience,approximately 1.07%of the study area was identified as having high potential for cropland development.Four key potential areas were further identified:the Shannan Valley,the Nyingchi Valley,the Zanda Valley,and the Gonghe Basin.These areas boast abundant potentially available cropland resources and ecological resettlement capacities,which leads us to recommend strategic priorities for comprehensive land consolidation and water development.This study has practical significance for optimizing land resource allocation and guiding decision-making related to ecological migration on the QTP.展开更多
Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divide...Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that: 1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space,which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones,ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.展开更多
Monte-Carlo method is used for estimating coalbed methane （CBM） resources in key coal mining areas of China. Monte-Carlo method is shown to be superior to the traditional volumetric method with constant parameters i...Monte-Carlo method is used for estimating coalbed methane （CBM） resources in key coal mining areas of China. Monte-Carlo method is shown to be superior to the traditional volumetric method with constant parameters in the calculation of CBM resources. The focus of the article is to introduce the main algorithm and the realization of functions estimated by Monte-Carlo method, including selection of parameters, determination of distribution function, generation of pseudo-random numbers, and evaluation of the parameters corresponding to pseudo-random numbers. A specified software on the basis of Monte-Carlo method is developed using Visual C＋＋ for the assessment of the CBM resources. A case study shows that calculation results using Monte-Carlo method have smaller error range in comparison with those using volumetric method.展开更多
Since the implementation of the Action Plan for Air Pollution Prevention and Control , all regions of China have steadily promoted the prevention and control of air pollution and achieved results continuously. However...Since the implementation of the Action Plan for Air Pollution Prevention and Control , all regions of China have steadily promoted the prevention and control of air pollution and achieved results continuously. However, the atmospheric environment in key areas such as Beijing-Tianjin-Hebei region, the Yangtze River Delta region, and Fenwei Plain is still severe, and especially during the heating period heavy pollution occurs frequently, which has become the focus and difficulty of improving the quality of the atmospheric environment and is also the weakest link of China s air pollution control at present. How to alleviate air pollution, how to win the battle of pollution prevention and control, how to hold the fruits of the blue sky defense war, energy consumption is key.展开更多
As one of the important policies of promoting the formation of main functional areas, the industrial policy directly determines the sustainable growth of space control ability of main functional areas. A restricted de...As one of the important policies of promoting the formation of main functional areas, the industrial policy directly determines the sustainable growth of space control ability of main functional areas. A restricted development zone is a type of main functional area which provides agricultural products and ecological products, assures the supply of national agricultural products and the stability of ecosystems, as well as safeguards the ecological functions and agricultural functions of wider regions by restricting its own development. Therefore scientific, complete and operable industrial policy support is needed. Restricted development zones are distributed widely in western China. With the restriction of their main functions, differential industrial policies should be implemented in the development of the restricted development zones: Dealing well with the relationship between industrial development and ecological protection, developing special industries which are friendly to resources and environment and appropriate for local conditions, guiding and encouraging industries to learn from regions with favorable development conditions, orderly withdrawing industries and enterprises adverse to main functions, facilitating industrial structure upgrading, optimizing industrial organization, improving industrial technological level and rationalizing industrial layout.展开更多
The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydro...The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydrocarbon generation and expulsion from source rocks, multi-cycle hydrocarbon enrichment and accumulation, and multi-phase reservoir adjustment and reconstruction. The enrichment, accumulation and distribution of hydrocarbon is mainly controlled by the source rock kitchen, paleo- anticline, regional cap rock and intensity of tectonic movement. In this paper, the T-BCMS model has been developed to predict favorable areas of hydrocarbon accumulation in complicated superimposed basins according to time and spatial relationships among five key factors. The five factors include unconformity surface representing tectonic balancing （B）, regional cap rock representing hydrocarbon protection （C）, paleo-anticline representing hydrocarbon migration and accumulation （M）, source rock kitchen representing hydrocarbon generation and expulsion （S） and geological time （T）. There are three necessary conditions to form favorable areas of hydrocarbon accumulation. First, four key factors BCMS should be strictly in the order of BCMS from top to bottom. Second, superimposition of four key factors BCMS in the same area is the most favorable for hydrocarbon accumulation. Third, vertically ordered combination and superimposition in the same area of BCMS should occur at the same geological time. The model has been used to predict the most favorable exploration areas in Ordovician in the Tarim Basin in the main hydrocarbon accumulation periods. The result shows that 95% of the discovered Ordovician hydrocarbon reservoirs are located in the predicted areas, which indicates the feasibility and reliability of the key factor matching T-BCMS model for hydrocarbon accumulation and enrichment.展开更多
In the case study in Agricultural Area of Tibet, the process and characteristics of farmers' land use were surveyed by semi-structural interview questionnaire. By comparing the change of land covers and farmers...In the case study in Agricultural Area of Tibet, the process and characteristics of farmers' land use were surveyed by semi-structural interview questionnaire. By comparing the change of land covers and farmers' land decision in two periods, the spatial connection of them was obtained. And the relations among farmers' land decision, land use change and environment were examined by calculating emergy and value flow. The results show that: hunting the maximal profits is the primary aim of farmers' land decision; farmers' land decision is incompatible with sustainable land use presently; farmers' land decision and land cover can be embodied spatially by each other; the change of farmers' land decision can be monitored by observing the change of land cover, and the sustainability of farmers' land decision can be appraised by calculating emergy and value flow.展开更多
Taking 138 key rural tourism villages in Beijing for example,this paper applied GIS analysis to analyze the spatial distribution characteristics of these villages,selected the influence factors of the villages conside...Taking 138 key rural tourism villages in Beijing for example,this paper applied GIS analysis to analyze the spatial distribution characteristics of these villages,selected the influence factors of the villages considering the classification characteristics,so as to explore the impact of different influence factors on its spatial distribution.The results showed(i)Key rural tourism villages in Beijing manifested an aggregated distribution on the whole,they were unevenly distributed and mostly located in the fringe area of northern mountainous areas and plains,such as Huairou District and Miyun District.Such a“multi-center distribution”pattern was significantly influenced by terrains and natural resources.(ii)Depending on local natural and cultural resources,tourism resources,development characteristics and functional differences,key rural tourism villages in Beijing could be devided into natural scenery type,scenic area-dependent type and agriculture experiencing type.(iii)Key factors influencing the distribution of these villages included mean temperature,annual precipitation,quantity of scenic area,road network density,agricultural land and so on,and the interaction of dual factors exerted more significant impact on single factors.展开更多
Wireless body area networks(WBANs)are an emerging technology for the real-time monitoring of physiological signals.WBANs provide a mechanism for collecting,storing,and transmitting physiological data to healthcare pro...Wireless body area networks(WBANs)are an emerging technology for the real-time monitoring of physiological signals.WBANs provide a mechanism for collecting,storing,and transmitting physiological data to healthcare providers.However,the open wireless channel and limited resources of sensors bring security challenges.To ensure physiological data security,this paper provides an efficient Certificateless Public Key Infrastructure Heterogeneous Ring Signcryption(CP-HRSC)scheme,in which sensors are in a certificateless cryptosystem(CLC)environment,and the server is in a public key infrastructure(PKI)environment.CLC could solve the limitations of key escrow in identity-based cryptography(IBC)and certificate management for public keys in PKI.While PKI is suited for the server because it is widely used on the Internet.Furthermore,this paper designs a ring signcryption method that allows the controller to anonymously encrypt physiological data on behalf of a set of sensors,but the server does not exactly know who the sensor is.The construction of this paper can achieve anonymity,confidentiality,authentication,non-repudiation,and integrity in a logically single step.Under the computational Diffie-Hellman(CDH)problem,the formal security proof is provided in the random oracle model(ROM).This paper demonstrates that this scheme has indistinguishability against adaptive chosen ciphertext attacks(IND-CCA2)and existential unforgeability against adaptive chosen message attacks(EUF-CMA).In terms of computational cost and energy usage,a comprehensive performance analysis demonstrates that the proposed scheme is the most effective.Compared to the three existing schemes,the computational cost of this paper’s scheme is reduced by about 49.5%,4.1%,and 8.4%,and the energy usage of our scheme is reduced by about 49.4%,3.7%,and 14.2%,respectively.展开更多
The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling ...The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling in Chongqing.And after more than ten years of deep and careful cultivation,a series of important achievements have been obtained in the exploration and development.From the perspective of exploration and development history,theory and technology,this paper systematically summarizes the exploration discovery process and productivity construction progress of shale gas in the demonstration area,expounds the geological exploration theories and key technologies of mountain shale gas,and predicts their development prospect and direction.And the following research results are obtained.First,the exploration and development in the demonstration area has gone through five development stages,and so far,three major productivity construction zones have been formed,including Huangjinba and Zijinba middleedeep shale gas zones and Taiyang shallow shale gas zone,with cumulative proved geological reserves more than 3100×10^(8) m^(3) and cumulative gas production more than 72×10^(8) m^(3).It has been constructed into the third largest green shale gas demonstration base in China.Second,the“multi-field coordination and multi-element coupling”mountain shale gas enrichment,accumulation and occurrence theory of“sedimentary background controlling source rock and reservoir,reworking intensity controlling preservation,and three-dimensional sealing controlling enrichment”is put forward innovatively,and the“three-dimensional sealing system”accumulation model of extrabasinal shallow shale gas is established.Third,a series of zone selection and evaluation technologies for mountain shale gas in strongly reworked complex structural areas have been developed,and the concept of geologyeengineering integration has first been adopted to create transparent shale gas reservoirs and cultivate high-yield wells.A major exploration breakthrough has been achieved from marginal basin medium deep shale gas layers to extrabasin ultra shallow to medium shallow ones,and domestic first large-scale monoblock shallow shale gas field with reserves over 2570×10^(8) m^(3) has been discovered.Fourth,a landmark technological achievement and efficient development model with geologyeengineering integration and shale geomechanical evaluation as the core has been formed,which leads the clean,green and efficient exploration and development of mountain shale gas.In conclusion,it is necessary to implement the exploration strategic idea of“two outgoing”in the demonstration area,i.e.,“walking out of the stable area of the basin and marching into the complex structure areas in the Dianqianbei Depression”and“walking out of the WufengeLongmaxi Formation and exploring other layers for breakthrough”.What's more,it is recommended to carry out the double-layer stereoscopic horizontal well pattern deployment of“Leping Formation CBM(coal measure gas)þLongmaxi Formation shale gas”appropriately in a large scale,so as to establish a new integrated development model for the three-dimensional efficient development of mountain shale gas and CBM.展开更多
Temporal key integrity protocol （TKIP） is a sub-protocol of IEEE 802.11i. TKIP remedies some security flaws in wired equivalent privacy （WEP） protocol. TKIP adds four new algorithms to WEP： a message integrity co...Temporal key integrity protocol （TKIP） is a sub-protocol of IEEE 802.11i. TKIP remedies some security flaws in wired equivalent privacy （WEP） protocol. TKIP adds four new algorithms to WEP： a message integrity code （MIC） called Michael, an initialization vector （IV） sequencing discipline, a key mixing function and a reeying mechanism. The key mixing function, also called temporal key hash, de-correlates the IVs from weak keys. Some cryptographic properties of the substitution box （S-box） used in the key mixing function are investigated in this paper, such as regularity, avalanche effect, differ uniform and linear structure. Moen et al pointed out that there existed a temporal key recovery attack in TKIP key mixing function. In this paper a method is proposed to defend against the attack, and the resulting effect on performance is discussed.展开更多
Ecosystem services are transferred from the service-providing area to the service-benefiting area to satisfy human needs through some substance, energy or information. Most studies focus on the provision of ecosystem ...Ecosystem services are transferred from the service-providing area to the service-benefiting area to satisfy human needs through some substance, energy or information. Most studies focus on the provision of ecosystem services and few focus on the demands on ecosystem services and their spatial distribution. Here, on the basis of the flow of water conservation services from the providing area to the benefiting area, the benefits produced by water conservation service are investigated and the benefiting areas are identified. The results indicate that in 2010 the water conservation service of key ecological function areas provided irrigation water for 1.67×105 km2 of paddy fields and 1.01×105 km2 irrigated fields, domestic water to urban residents and industrial water to factories, mines and enterprises of 2.64×104 km2 urban construction land and domestic water to rural residents across 3.73×104 km2 of rural settlements and formed 6.64×104 km2 of inland water which can be used for freshwater aquaculture, downstream regions comprise 1.31×104 km of navigable river, which can be used for inland shipping. The benefit areas of the key function areas located in the upper and middle reaches of the Yangtze River are greater and more influential benefit areas. To protect these key function areas, more attention should be paid to the maintenance and improvement of water conservation. Some benefit areas have access to the benefits produced by water conservation of nine key ecological function areas and cover 17% of the overall benefit area and the length of their channels benefited accounts for 7%. Multiple key ecological function areas should be taken into account equally in the formulation of ecological compensation policies. These research findings can serve as a scientific basis for the compensated use of and ecological compensation for ecosystem services provided by key ecological function areas.展开更多
Soil erosion is a significant factor in the deterioration of the ecological environment and soil conservation is an important ecological service of National Key Ecological Function Areas in China. Here, climate, terra...Soil erosion is a significant factor in the deterioration of the ecological environment and soil conservation is an important ecological service of National Key Ecological Function Areas in China. Here, climate, terrain, soil and vegetation cover, soil erosion and soil conservation spatial data in 25 National Key Ecological Function Areas in 2010 were analyzed using the Universal Soil Loss Equation by Arc GIS tool. We found that soil conservation effects due to vegetation cover and soil conservation measures are obvious and that micro and slight erosion areas in National Key Ecological Function Areas have increased by 26.2%. The area of intensive erosion decreased by 25.1%, and the soil conservation amount in southern National Key Ecological Function Areas is high. The conservation amount of soil nutrients within National Key Ecological Function Areas is related to amount of soil conservation and content of each nutrient element in soil. The sequence of nutrient conservation amounts from high to low is soil organic carbon, total K, total N and total P in soil. The conservation amount of various soil nutrient elements in the Alkin Grassland function area and Yunnan and Sichuan function area was highest. Based on our findings, we recommend the strengthening of vegetation protection and management in the areas with high per unit area soil erosion, enhancement of vegetation cover and improvement of soil conservation measures in order to improve soil conservation functions and reduce soil nutrient losses. Vegetation protection and soil conservation measures should be consolidated in the areas with high potential erosion to prevent further deterioration.展开更多
At the end of the 1990 s China started to construct an ecological compensation system for national key ecological function areas. An eco-compensation system focusing on the ＂Transfer Payment of National Key Ecologica...At the end of the 1990 s China started to construct an ecological compensation system for national key ecological function areas. An eco-compensation system focusing on the ＂Transfer Payment of National Key Ecological Function Areas＂ has been established. The current eco-compensation system has played a positive role in improving the ecological environment of national key ecological function areas; but the ecological effect is weakening due to existing problems in the eco-compensation system such as unreasonable calculation of compensation standards, poor expression of rights and interests of stakeholders, simple sources of capital and modes of compensation. For better development, the eco-compensation system should be improved by（i） adhering to the combination of vertical compensation（oriented） and horizontal compensation（auxiliary） on the whole and establishing a transfer payment system of eco-compensation at national scale;（ii） defining the compensation standard according to ecological protection costs, development opportunity costs and ecological service values and adding indicators that reflect economic green transformation to evaluate compensation effects;（iii） gradually building a utilization system of eco-compensation funds in which multi-stakeholders participate and establishing a green development-oriented system to evaluate the performance of local governments; and（iv） cultivating a new business pattern where ecological services are the product, to grow the ecological service industry.展开更多
1.Agricultural produce Wholesale markets in cities to be monitored;five poisonous pesticides banned. 2.Processed food Production and processing plants must hold permits.Small companies must guarantee product safety. 3...1.Agricultural produce Wholesale markets in cities to be monitored;five poisonous pesticides banned. 2.Processed food Production and processing plants must hold permits.Small companies must guarantee product safety. 3.Food in circulation Markets in cities of county-level and above must get qualification proof and receipts from suppliers. Small grocery stores must record purchases.展开更多
Subject Code:C03 With the support by the National Natural Science Foundation of China and Ministry of Science and Technology of China,the research team led by Dr.Wu Ruidong(武瑞东)from Yunnan University reveals severa...Subject Code:C03 With the support by the National Natural Science Foundation of China and Ministry of Science and Technology of China,the research team led by Dr.Wu Ruidong(武瑞东)from Yunnan University reveals several key limitations in the study of global roadless areas mapping and assessment,which was展开更多
Based on thorough researches on the Chinese wireless local area network （WLAN） security standard, i. e., WLAN authentication and privacy infrastructure （WAPI）, the security of the authentication access process is ...Based on thorough researches on the Chinese wireless local area network （WLAN） security standard, i. e., WLAN authentication and privacy infrastructure （WAPI）, the security of the authentication access process is analyzed with the CK （Canetti-Krawczyk） model and the BAN （Burrows-Abadi- Needham） logic. Results show that it can achieve the alleged authentication and key negotiation goals. Besides those alleged, further analyses indicate that the authentication access process can satisfy other security requirements, such as mutual identity authentication, mutual key control, key confirmation, message integrity check, etc. If the used elliptic curve encryption algorithm and the hash algorithm are secure enough, the protocol can efficiently realize mutual authentication between STAs （station） and APs （access point）. Therefore, WAPI can be applied to replace the security mechanism used in the original WLAN international standard to enhance its security.展开更多
Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guang...Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guangdong-Hong Kong-Macao Greater Bay Area(GBA),as one of China's most economically active regions,serves as a key engine for economic growth while also facing considerable carbon emission challenges.This study analyzes the industrial emission volume and geographical distribution of key emitting enterprises in the GBA,summarizes their technological processes and main carbonemitting equipment,and provides scientific support for precise mitigation policies and low-carbon development.Based on data from 176 key emitting enterprises,the study reveals that Guangzhou and Dongguan host the largest number of such enterprises.Carbon emissions are primarily concentrated in the power sector,dominated by coal-and gas-fired power units,characterized by significant spatial dispersion and uneven distribution.Beyond the power sector,the paper industry has a high number of enterprises but lower emissions.Key facilities such as boilers,cogeneration systems,and production lines are predominantly located near tributaries rivers in Dongguan and Jiangmen.The building materials sector,primarily cement production,ranks as the second-largest emitter,with hightemperature kilns and grinding equipment,particularly rotary kilns and glass furnaces,as the main sources.The petrochemical and chemical sectors have fewer enterprises and lower emissions in the GBA,mainly located in suburban industrial clusters.Carbon emissions in the GBA exhibit distinct industry concentration and geographical distribution disparities.This study provides crucial data and theoretical insights for the development of targeted emission reduction strategies,optimization of source-sink matching,and the advancement of CCUS technologies in the region,particularly from the GBA to the northern South China Sea.展开更多
National key eco-function zones for water and soil conservation are exceptionally fragile areas in terms of their eco-environments and are also severely affected by water and soil loss. They have been a focus of atten...National key eco-function zones for water and soil conservation are exceptionally fragile areas in terms of their eco-environments and are also severely affected by water and soil loss. They have been a focus of attention from all sectors of society. This research assesses important ecosystem service functions and their values using such indexes as NPP, soil conservation quantity and water conservation quantity. The result indicates that the ecosystem services of China＇s eco-function zones for water and soil conservation are worth 3268.90×10^8 CNY in total, of which organic matter production accounts for 530.96×10^8 CNY, nutrient substance circulation and storage 301.91×10^8 CNY, carbon fixation and oxygen release 1616.16×10^8 CNY, soil conservation 442.70×10^8 CNY and water source conservation 816.20×10^8 CNY. Of the four functional zones, the Guangxi-Guizhou-Yunnan Area registers the highest value of 1551.30×10^8 CNY, and the Three Gorges Reservoir Area the lowest value of 448.15×10^8CNY. In terms of ecosystem service value per unit of area, the Guangxi-Guizhou-Yunnan Area takes the first place, followed by Three Gorges Reservoir Area and the Dabie Mountain Area, which are roughly equivalent, and finally the Loess Plateau Area is at the bottom.展开更多
基金The Second Tibetan Plateau Scientific Expedition and Research ProgramNo.2019QZKK0406。
文摘Cropland suitability analysis is a vital tool for ensuring food security and sustainable agriculture,coordinating ecological space with human activity space on the Qinghai-Tibet Plateau(QTP).However,there are few studies on complete and accurate cropland suitability assessments on the QTP,let alone on identifying key potential areas for cropland development.We used a novel assessment model to generate a 30-m cropland suitability map for the QTP.The identification of areas with cropland development potential and the evaluation of potentially available cropland were further integrated into a unified analytical framework.We found that only 10.18%of the study area is suitable for large-scale and permanent cropland.Moreover,approximately 72.75%of the existing cropland was found to be distributed in suitable or marginally suitable areas.Considering the trade-offs related to irrigation water supply convenience,approximately 1.07%of the study area was identified as having high potential for cropland development.Four key potential areas were further identified:the Shannan Valley,the Nyingchi Valley,the Zanda Valley,and the Gonghe Basin.These areas boast abundant potentially available cropland resources and ecological resettlement capacities,which leads us to recommend strategic priorities for comprehensive land consolidation and water development.This study has practical significance for optimizing land resource allocation and guiding decision-making related to ecological migration on the QTP.
基金Under the auspices of Grant Program of Clean Development Mechanism Fund of China(CDMF)(No.2014092)Task 2 of Key Service Project 5 for the Characteristic Institute of Chinese Academy of Sciences(No.TSS-2015-014-FW-5-2)+2 种基金National Natural Science Foundation of China(No.41571159)The Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA20010301)Jiangsu Natural Science Foundation(No.BK20181105)
文摘Three types of spatial function zoning is an effective measure for regional environmental protection and orderly development.For ecological and economic coordinated development, spatial function zones should be divided scientifically to clear its direction of development and protection. Therefore, based on ecological constraints, a beneficial discussion would be about the key ecological function areas adopting the concept of ecological protection restriction and supporting socioeconomic development for spatial function zoning. In this paper, the researchers, taking Tacheng Basin, Xinjiang of China as an example, choose township as basic research unit and set up an evaluation index system from three aspects, namely, ecological protection suitability, agricultural production suitability, and urban development suitability, which are analyzed by using spatial analysis functions and exclusive matrix method. The results showed that: 1) This paper formed a set of multilevel evaluation index systems for three types of spatial function zoning of the key ecological function areas based on a novel perspective by scientifically dividing Tacheng Basin into ecological space, agricultural space, and urban space,which realized the integration and scientific orientation for spatial function at the township scale. 2) Under the guidance of three types of spatial pattern, the functional orientation and suggestions of development and protection was clearly defined for ecological protection zones,ecological economic zones, agricultural production zones, and urban development zones. 3) A new idea of space governance is provided to promote the coordinated and sustainable development between ecology and economy, which can break the traditional mode of thinking about regional economic development, and offers a scientific basis and reference for macro decision-making.
基金supported by the National Natural Science Foundation of China (No. 40730422)the Foundation of China University of Mining & Technology (No. OF061003)State Key Laboratory of Geological Processes and Mineral Resources (No. GPMR2007-11)
文摘Monte-Carlo method is used for estimating coalbed methane （CBM） resources in key coal mining areas of China. Monte-Carlo method is shown to be superior to the traditional volumetric method with constant parameters in the calculation of CBM resources. The focus of the article is to introduce the main algorithm and the realization of functions estimated by Monte-Carlo method, including selection of parameters, determination of distribution function, generation of pseudo-random numbers, and evaluation of the parameters corresponding to pseudo-random numbers. A specified software on the basis of Monte-Carlo method is developed using Visual C＋＋ for the assessment of the CBM resources. A case study shows that calculation results using Monte-Carlo method have smaller error range in comparison with those using volumetric method.
基金Supported by Special Project for Research on Prevention and Control of Air Pollution from Fire Coal in 2018 of Ministry of Ecology and Environment of the People’s Republic of China(2018A030)National Natural Science Foundation of China(41771498)
文摘Since the implementation of the Action Plan for Air Pollution Prevention and Control , all regions of China have steadily promoted the prevention and control of air pollution and achieved results continuously. However, the atmospheric environment in key areas such as Beijing-Tianjin-Hebei region, the Yangtze River Delta region, and Fenwei Plain is still severe, and especially during the heating period heavy pollution occurs frequently, which has become the focus and difficulty of improving the quality of the atmospheric environment and is also the weakest link of China s air pollution control at present. How to alleviate air pollution, how to win the battle of pollution prevention and control, how to hold the fruits of the blue sky defense war, energy consumption is key.
基金the paper is the phased achievement of Projects of the National Social Science Foundation of China——“Study on the Supporting Policies in Limited Development Zones”(11BJL058) directed by the author
文摘As one of the important policies of promoting the formation of main functional areas, the industrial policy directly determines the sustainable growth of space control ability of main functional areas. A restricted development zone is a type of main functional area which provides agricultural products and ecological products, assures the supply of national agricultural products and the stability of ecosystems, as well as safeguards the ecological functions and agricultural functions of wider regions by restricting its own development. Therefore scientific, complete and operable industrial policy support is needed. Restricted development zones are distributed widely in western China. With the restriction of their main functions, differential industrial policies should be implemented in the development of the restricted development zones: Dealing well with the relationship between industrial development and ecological protection, developing special industries which are friendly to resources and environment and appropriate for local conditions, guiding and encouraging industries to learn from regions with favorable development conditions, orderly withdrawing industries and enterprises adverse to main functions, facilitating industrial structure upgrading, optimizing industrial organization, improving industrial technological level and rationalizing industrial layout.
基金supported by the National Basic Research Program (2006CB202308)
文摘The geologic conditions of superimposed basins in China are very complicated. This is mainly shown by multi-phase structural evolution, multiple sets of source-reservoir-cap rock combinations, multiple stages of hydrocarbon generation and expulsion from source rocks, multi-cycle hydrocarbon enrichment and accumulation, and multi-phase reservoir adjustment and reconstruction. The enrichment, accumulation and distribution of hydrocarbon is mainly controlled by the source rock kitchen, paleo- anticline, regional cap rock and intensity of tectonic movement. In this paper, the T-BCMS model has been developed to predict favorable areas of hydrocarbon accumulation in complicated superimposed basins according to time and spatial relationships among five key factors. The five factors include unconformity surface representing tectonic balancing （B）, regional cap rock representing hydrocarbon protection （C）, paleo-anticline representing hydrocarbon migration and accumulation （M）, source rock kitchen representing hydrocarbon generation and expulsion （S） and geological time （T）. There are three necessary conditions to form favorable areas of hydrocarbon accumulation. First, four key factors BCMS should be strictly in the order of BCMS from top to bottom. Second, superimposition of four key factors BCMS in the same area is the most favorable for hydrocarbon accumulation. Third, vertically ordered combination and superimposition in the same area of BCMS should occur at the same geological time. The model has been used to predict the most favorable exploration areas in Ordovician in the Tarim Basin in the main hydrocarbon accumulation periods. The result shows that 95% of the discovered Ordovician hydrocarbon reservoirs are located in the predicted areas, which indicates the feasibility and reliability of the key factor matching T-BCMS model for hydrocarbon accumulation and enrichment.
文摘In the case study in Agricultural Area of Tibet, the process and characteristics of farmers' land use were surveyed by semi-structural interview questionnaire. By comparing the change of land covers and farmers' land decision in two periods, the spatial connection of them was obtained. And the relations among farmers' land decision, land use change and environment were examined by calculating emergy and value flow. The results show that: hunting the maximal profits is the primary aim of farmers' land decision; farmers' land decision is incompatible with sustainable land use presently; farmers' land decision and land cover can be embodied spatially by each other; the change of farmers' land decision can be monitored by observing the change of land cover, and the sustainability of farmers' land decision can be appraised by calculating emergy and value flow.
文摘Taking 138 key rural tourism villages in Beijing for example,this paper applied GIS analysis to analyze the spatial distribution characteristics of these villages,selected the influence factors of the villages considering the classification characteristics,so as to explore the impact of different influence factors on its spatial distribution.The results showed(i)Key rural tourism villages in Beijing manifested an aggregated distribution on the whole,they were unevenly distributed and mostly located in the fringe area of northern mountainous areas and plains,such as Huairou District and Miyun District.Such a“multi-center distribution”pattern was significantly influenced by terrains and natural resources.(ii)Depending on local natural and cultural resources,tourism resources,development characteristics and functional differences,key rural tourism villages in Beijing could be devided into natural scenery type,scenic area-dependent type and agriculture experiencing type.(iii)Key factors influencing the distribution of these villages included mean temperature,annual precipitation,quantity of scenic area,road network density,agricultural land and so on,and the interaction of dual factors exerted more significant impact on single factors.
基金supported by the Postgraduate Research&Practice Innovation Program of Jiangsu Province (Grant No.SJCX22_1677).
文摘Wireless body area networks(WBANs)are an emerging technology for the real-time monitoring of physiological signals.WBANs provide a mechanism for collecting,storing,and transmitting physiological data to healthcare providers.However,the open wireless channel and limited resources of sensors bring security challenges.To ensure physiological data security,this paper provides an efficient Certificateless Public Key Infrastructure Heterogeneous Ring Signcryption(CP-HRSC)scheme,in which sensors are in a certificateless cryptosystem(CLC)environment,and the server is in a public key infrastructure(PKI)environment.CLC could solve the limitations of key escrow in identity-based cryptography(IBC)and certificate management for public keys in PKI.While PKI is suited for the server because it is widely used on the Internet.Furthermore,this paper designs a ring signcryption method that allows the controller to anonymously encrypt physiological data on behalf of a set of sensors,but the server does not exactly know who the sensor is.The construction of this paper can achieve anonymity,confidentiality,authentication,non-repudiation,and integrity in a logically single step.Under the computational Diffie-Hellman(CDH)problem,the formal security proof is provided in the random oracle model(ROM).This paper demonstrates that this scheme has indistinguishability against adaptive chosen ciphertext attacks(IND-CCA2)and existential unforgeability against adaptive chosen message attacks(EUF-CMA).In terms of computational cost and energy usage,a comprehensive performance analysis demonstrates that the proposed scheme is the most effective.Compared to the three existing schemes,the computational cost of this paper’s scheme is reduced by about 49.5%,4.1%,and 8.4%,and the energy usage of our scheme is reduced by about 49.4%,3.7%,and 14.2%,respectively.
基金Project supported by the Scientific Research and Technology Development Project PetroChina Company Limited“Research on microscopic characteristics and enrichment mechanism of shallow shale gas reservoirs in Zhaotong”(No.2021DJ1903)“Field test of downhole fiber intelligent monitoring technology”(No.2020F-44).
文摘The Zhaotong national shale gas demonstration area in Yunnan(hereinafter referred to as demonstration area)is China's third largest national shale gas production base after ChangningeWeiyuan in Sichuan and Fuling in Chongqing.And after more than ten years of deep and careful cultivation,a series of important achievements have been obtained in the exploration and development.From the perspective of exploration and development history,theory and technology,this paper systematically summarizes the exploration discovery process and productivity construction progress of shale gas in the demonstration area,expounds the geological exploration theories and key technologies of mountain shale gas,and predicts their development prospect and direction.And the following research results are obtained.First,the exploration and development in the demonstration area has gone through five development stages,and so far,three major productivity construction zones have been formed,including Huangjinba and Zijinba middleedeep shale gas zones and Taiyang shallow shale gas zone,with cumulative proved geological reserves more than 3100×10^(8) m^(3) and cumulative gas production more than 72×10^(8) m^(3).It has been constructed into the third largest green shale gas demonstration base in China.Second,the“multi-field coordination and multi-element coupling”mountain shale gas enrichment,accumulation and occurrence theory of“sedimentary background controlling source rock and reservoir,reworking intensity controlling preservation,and three-dimensional sealing controlling enrichment”is put forward innovatively,and the“three-dimensional sealing system”accumulation model of extrabasinal shallow shale gas is established.Third,a series of zone selection and evaluation technologies for mountain shale gas in strongly reworked complex structural areas have been developed,and the concept of geologyeengineering integration has first been adopted to create transparent shale gas reservoirs and cultivate high-yield wells.A major exploration breakthrough has been achieved from marginal basin medium deep shale gas layers to extrabasin ultra shallow to medium shallow ones,and domestic first large-scale monoblock shallow shale gas field with reserves over 2570×10^(8) m^(3) has been discovered.Fourth,a landmark technological achievement and efficient development model with geologyeengineering integration and shale geomechanical evaluation as the core has been formed,which leads the clean,green and efficient exploration and development of mountain shale gas.In conclusion,it is necessary to implement the exploration strategic idea of“two outgoing”in the demonstration area,i.e.,“walking out of the stable area of the basin and marching into the complex structure areas in the Dianqianbei Depression”and“walking out of the WufengeLongmaxi Formation and exploring other layers for breakthrough”.What's more,it is recommended to carry out the double-layer stereoscopic horizontal well pattern deployment of“Leping Formation CBM(coal measure gas)þLongmaxi Formation shale gas”appropriately in a large scale,so as to establish a new integrated development model for the three-dimensional efficient development of mountain shale gas and CBM.
基金the National Laboratory for Modern Communications(No.51436050304JW0317)the National Natural Science Foundation of China(No.60573030)
文摘Temporal key integrity protocol （TKIP） is a sub-protocol of IEEE 802.11i. TKIP remedies some security flaws in wired equivalent privacy （WEP） protocol. TKIP adds four new algorithms to WEP： a message integrity code （MIC） called Michael, an initialization vector （IV） sequencing discipline, a key mixing function and a reeying mechanism. The key mixing function, also called temporal key hash, de-correlates the IVs from weak keys. Some cryptographic properties of the substitution box （S-box） used in the key mixing function are investigated in this paper, such as regularity, avalanche effect, differ uniform and linear structure. Moen et al pointed out that there existed a temporal key recovery attack in TKIP key mixing function. In this paper a method is proposed to defend against the attack, and the resulting effect on performance is discussed.
基金the National Science and Technology Support Program(2013BAC03B05)the National Natural Science Foundation of China(31400411)
文摘Ecosystem services are transferred from the service-providing area to the service-benefiting area to satisfy human needs through some substance, energy or information. Most studies focus on the provision of ecosystem services and few focus on the demands on ecosystem services and their spatial distribution. Here, on the basis of the flow of water conservation services from the providing area to the benefiting area, the benefits produced by water conservation service are investigated and the benefiting areas are identified. The results indicate that in 2010 the water conservation service of key ecological function areas provided irrigation water for 1.67×105 km2 of paddy fields and 1.01×105 km2 irrigated fields, domestic water to urban residents and industrial water to factories, mines and enterprises of 2.64×104 km2 urban construction land and domestic water to rural residents across 3.73×104 km2 of rural settlements and formed 6.64×104 km2 of inland water which can be used for freshwater aquaculture, downstream regions comprise 1.31×104 km of navigable river, which can be used for inland shipping. The benefit areas of the key function areas located in the upper and middle reaches of the Yangtze River are greater and more influential benefit areas. To protect these key function areas, more attention should be paid to the maintenance and improvement of water conservation. Some benefit areas have access to the benefits produced by water conservation of nine key ecological function areas and cover 17% of the overall benefit area and the length of their channels benefited accounts for 7%. Multiple key ecological function areas should be taken into account equally in the formulation of ecological compensation policies. These research findings can serve as a scientific basis for the compensated use of and ecological compensation for ecosystem services provided by key ecological function areas.
基金the National Science and Technology Support Program(2013BAC03B05)the National Natural Science Foundation of China(41101539)
文摘Soil erosion is a significant factor in the deterioration of the ecological environment and soil conservation is an important ecological service of National Key Ecological Function Areas in China. Here, climate, terrain, soil and vegetation cover, soil erosion and soil conservation spatial data in 25 National Key Ecological Function Areas in 2010 were analyzed using the Universal Soil Loss Equation by Arc GIS tool. We found that soil conservation effects due to vegetation cover and soil conservation measures are obvious and that micro and slight erosion areas in National Key Ecological Function Areas have increased by 26.2%. The area of intensive erosion decreased by 25.1%, and the soil conservation amount in southern National Key Ecological Function Areas is high. The conservation amount of soil nutrients within National Key Ecological Function Areas is related to amount of soil conservation and content of each nutrient element in soil. The sequence of nutrient conservation amounts from high to low is soil organic carbon, total K, total N and total P in soil. The conservation amount of various soil nutrient elements in the Alkin Grassland function area and Yunnan and Sichuan function area was highest. Based on our findings, we recommend the strengthening of vegetation protection and management in the areas with high per unit area soil erosion, enhancement of vegetation cover and improvement of soil conservation measures in order to improve soil conservation functions and reduce soil nutrient losses. Vegetation protection and soil conservation measures should be consolidated in the areas with high potential erosion to prevent further deterioration.
文摘At the end of the 1990 s China started to construct an ecological compensation system for national key ecological function areas. An eco-compensation system focusing on the ＂Transfer Payment of National Key Ecological Function Areas＂ has been established. The current eco-compensation system has played a positive role in improving the ecological environment of national key ecological function areas; but the ecological effect is weakening due to existing problems in the eco-compensation system such as unreasonable calculation of compensation standards, poor expression of rights and interests of stakeholders, simple sources of capital and modes of compensation. For better development, the eco-compensation system should be improved by（i） adhering to the combination of vertical compensation（oriented） and horizontal compensation（auxiliary） on the whole and establishing a transfer payment system of eco-compensation at national scale;（ii） defining the compensation standard according to ecological protection costs, development opportunity costs and ecological service values and adding indicators that reflect economic green transformation to evaluate compensation effects;（iii） gradually building a utilization system of eco-compensation funds in which multi-stakeholders participate and establishing a green development-oriented system to evaluate the performance of local governments; and（iv） cultivating a new business pattern where ecological services are the product, to grow the ecological service industry.
文摘1.Agricultural produce Wholesale markets in cities to be monitored;five poisonous pesticides banned. 2.Processed food Production and processing plants must hold permits.Small companies must guarantee product safety. 3.Food in circulation Markets in cities of county-level and above must get qualification proof and receipts from suppliers. Small grocery stores must record purchases.
文摘Subject Code:C03 With the support by the National Natural Science Foundation of China and Ministry of Science and Technology of China,the research team led by Dr.Wu Ruidong(武瑞东)from Yunnan University reveals several key limitations in the study of global roadless areas mapping and assessment,which was
基金The National Basic Research Program of China(973Program) (No.G1999035805)the Natural Science Foundation of ShannxiProvince (No.2007F37)China Postdoctoral Science Foundation (No.20060401008,20070410376).
文摘Based on thorough researches on the Chinese wireless local area network （WLAN） security standard, i. e., WLAN authentication and privacy infrastructure （WAPI）, the security of the authentication access process is analyzed with the CK （Canetti-Krawczyk） model and the BAN （Burrows-Abadi- Needham） logic. Results show that it can achieve the alleged authentication and key negotiation goals. Besides those alleged, further analyses indicate that the authentication access process can satisfy other security requirements, such as mutual identity authentication, mutual key control, key confirmation, message integrity check, etc. If the used elliptic curve encryption algorithm and the hash algorithm are secure enough, the protocol can efficiently realize mutual authentication between STAs （station） and APs （access point）. Therefore, WAPI can be applied to replace the security mechanism used in the original WLAN international standard to enhance its security.
基金supported by the National Natural Science Foundation of China(52304098,52106092,42376215,52474105)Shenzhen Science and Technology Program(JCYJ20220818095605012,JCYJ20220530113011027)+5 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515110338,2023A1515012316,2023A1515012761,2025A1515010748)Research Team Cultivation Program of Shenzhen University(2023QNT004)Shenzhen Key Laboratory of Natural Gas Hydrates(ZDSYS20200421111201738)the General Research Fund(No.12616222)Early Career Scheme(No.22611624)of Hong Kong Research Grants CouncilMajor Science and Technology Infrastructure Project of Material Genome Big–science Facilities Platform supported by the Municipal Development and Reform Commission of Shenzhen。
文摘Carbon Capture,Utilization,and Storage(CCUS)technology has gained widespread attention in recent years as a critical strategy to combat global climate change,particularly in achieving carbon neutrality goals.The Guangdong-Hong Kong-Macao Greater Bay Area(GBA),as one of China's most economically active regions,serves as a key engine for economic growth while also facing considerable carbon emission challenges.This study analyzes the industrial emission volume and geographical distribution of key emitting enterprises in the GBA,summarizes their technological processes and main carbonemitting equipment,and provides scientific support for precise mitigation policies and low-carbon development.Based on data from 176 key emitting enterprises,the study reveals that Guangzhou and Dongguan host the largest number of such enterprises.Carbon emissions are primarily concentrated in the power sector,dominated by coal-and gas-fired power units,characterized by significant spatial dispersion and uneven distribution.Beyond the power sector,the paper industry has a high number of enterprises but lower emissions.Key facilities such as boilers,cogeneration systems,and production lines are predominantly located near tributaries rivers in Dongguan and Jiangmen.The building materials sector,primarily cement production,ranks as the second-largest emitter,with hightemperature kilns and grinding equipment,particularly rotary kilns and glass furnaces,as the main sources.The petrochemical and chemical sectors have fewer enterprises and lower emissions in the GBA,mainly located in suburban industrial clusters.Carbon emissions in the GBA exhibit distinct industry concentration and geographical distribution disparities.This study provides crucial data and theoretical insights for the development of targeted emission reduction strategies,optimization of source-sink matching,and the advancement of CCUS technologies in the region,particularly from the GBA to the northern South China Sea.
基金National Natural Science Foundation of China(41371486)National Key Research and Development Program(2016YFC0503706,2016YFC0503403)
文摘National key eco-function zones for water and soil conservation are exceptionally fragile areas in terms of their eco-environments and are also severely affected by water and soil loss. They have been a focus of attention from all sectors of society. This research assesses important ecosystem service functions and their values using such indexes as NPP, soil conservation quantity and water conservation quantity. The result indicates that the ecosystem services of China＇s eco-function zones for water and soil conservation are worth 3268.90×10^8 CNY in total, of which organic matter production accounts for 530.96×10^8 CNY, nutrient substance circulation and storage 301.91×10^8 CNY, carbon fixation and oxygen release 1616.16×10^8 CNY, soil conservation 442.70×10^8 CNY and water source conservation 816.20×10^8 CNY. Of the four functional zones, the Guangxi-Guizhou-Yunnan Area registers the highest value of 1551.30×10^8 CNY, and the Three Gorges Reservoir Area the lowest value of 448.15×10^8CNY. In terms of ecosystem service value per unit of area, the Guangxi-Guizhou-Yunnan Area takes the first place, followed by Three Gorges Reservoir Area and the Dabie Mountain Area, which are roughly equivalent, and finally the Loess Plateau Area is at the bottom.
