It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications.As a standard of broadband wireless access systems,IEEE 802.16 adopts Orthogonal Frequency Divisi...It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications.As a standard of broadband wireless access systems,IEEE 802.16 adopts Orthogonal Frequency Division Multiplexing(OFDM)and multi-modulation/coding techniques at the physical layer,combines contend and pre-contract mechanisms at the Medium Access Control(MAC)layer.Based on the QoS-related concepts such as connection and service flow,IEEE 802.16 optimizes network entry and initialization,and frame format in order to improve network throughput,reduce network delay,and increase the flexibility of network configuration.Based on IEEE 802.16,WiMAX adopts Point-to-Multipoint(PMP)network topology to realize flexible networking.It is a typical application technology of broadband wireless access systems.展开更多
With the continuous enrichment of mobile communication application scenarios in the future, the traditional macro-cellular-based mobile communication network architecture will be difficult to meet the explosive growth...With the continuous enrichment of mobile communication application scenarios in the future, the traditional macro-cellular-based mobile communication network architecture will be difficult to meet the explosive growth in demand for communications services.展开更多
The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks(WMNs).There is a rule for wireless Ad hoc networks that ...The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks(WMNs).There is a rule for wireless Ad hoc networks that the average node capacity decreases while the number of nodes increases,so it is hard to establish a large-scale wireless Mesh network.Network scalability is very important for enhancing the adaptive networking capability of the wireless Mesh network.This article discusses key scalability technologies for Mesh Base Stations(BSs)and Mesh Mobile Stations(MSs),such as channel allocation,intelligent routing,multi-antenna,node classification,Quality of Service(QoS)differentiation and cooperative transmission.展开更多
When computers and communication devices are available everywhere in the future,the categories of communication will expand to cover not only the man-man and the man-machine,but also the machine-machine(M2M)communicat...When computers and communication devices are available everywhere in the future,the categories of communication will expand to cover not only the man-man and the man-machine,but also the machine-machine(M2M)communication.Someday,the traffic generated by machines will greatly exceed those of man-machine and man-man applications.Large numbers of M2M applications will need various wireless networks to support them.This paper introduces the characteristics,advantages and disadvantages of the currently available various wireless network technologies,including WiFi,Bluetooth,ZigBee,passive RFID and the 802.15 standard networks.展开更多
The network integration provides users with a new network with long connection time and a high data rate when needed,but it also brings the defects of all the networks that integrate together into the integrated netwo...The network integration provides users with a new network with long connection time and a high data rate when needed,but it also brings the defects of all the networks that integrate together into the integrated network.This will cause all kinds of existing and some new security problems in the operation of the integrated network.A complete protection based on recovery is proposed in the paper.It uses the public-key algorithm to authorize and private-key algorithm to encrypt the communicating data.This solution can provide the system with reliable security,and avoid Denial of Service(DoS)of the user.This solution has been proposed lately,and we should further identify the correct action of all the layers and figure out how to react when a legal node is framed by multiple malicious nodes.展开更多
The Peer-to-Peer(P2P)network traffic identification technology includes Transport Layer Identification(TLI)and Deep Packet Inspection(DPI)methods.By analyzing packets of the transport layer and the traffic characteris...The Peer-to-Peer(P2P)network traffic identification technology includes Transport Layer Identification(TLI)and Deep Packet Inspection(DPI)methods.By analyzing packets of the transport layer and the traffic characteristic in the P2P system,TLI can identify whether or not the network data flow belongs to the P2P system.The DPI method adopts protocol analysis technology and reverting technology.It picks up data from the P2P application layer and analyzes the characteristics of the payload to judge if the network traffic belongs to P2P applications.Due to its accuracy,robustness and classifying ability,DPI is the main method used to identify P2P traffic.Adopting the advantages of TLI and DPI,a precise and efficient technology for P2P network traffic identification can be designed.展开更多
Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research a...Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research at home and abroad regardless of the mention of its development of a national strategic level, it is called the third wave of the world information industry following the computer, and internet.展开更多
The 21 st century is an era of information technology, network technology is in all areas of life and production and also higher education administration began to apply network technology and network management. Howev...The 21 st century is an era of information technology, network technology is in all areas of life and production and also higher education administration began to apply network technology and network management. However, in the rapid development of information technology today, due to network with their own information technology, high-speed, information-based features are widely used in educational management in universities, so that some common problems on the network has infiltrated into university education management, making College Educational management in the New face new problems and challenges. Through the influence of network technology for Higher Education Management of the research on network technology we make a few constructive suggestions on education management application and Universities.展开更多
To find out an effective way to improve higher vocational college students＇ reading abilities, the author designs an experiment that applying the multimedia and network technologies in the higher vocational public En...To find out an effective way to improve higher vocational college students＇ reading abilities, the author designs an experiment that applying the multimedia and network technologies in the higher vocational public English reading teaching to test whether the multimedia teaching mode is more effective than the traditional teaching mode in enhancing vocational college students＇ reading performance. The contrastive experiment is done for one semester and the experiment shows that if applying multimedia and network technologies in higher vocational public English reading teaching, creating authentic language environment, it can improve the classroom efficiency, improve students＇ English reading ability, thus forming the student-centered modem higher vocational public English reading teaching mode,展开更多
As a smart spectrum sharing technology,Cognitive Radio(CR)is becoming a hot topic in the field of wireless telecommunications.Besides providing traditional services,the cognitive radio network Media Access Control(MAC...As a smart spectrum sharing technology,Cognitive Radio(CR)is becoming a hot topic in the field of wireless telecommunications.Besides providing traditional services,the cognitive radio network Media Access Control(MAC)layer is required to perform an entirely new set of functions for effective reusing spectrum opportunity,without causing any harmful interference to incumbents.Spectrum sensing management selects and optimizes sensing strategies and parameters by the selection of sensing mode,sensing period,sensing time,sensing channel,and sensing quiet period.Access control avoids collision with primary users mainly by cooperation access and transparent access.Dynamic spectrum allocation optimizes the allocation of uncertain spectrum for binary interference model and accumulative interference model.Security mechanism adds authentication and encryption mechanisms to MAC frame to defense MAC layer security attacks.Cross-layer design combines MAC layer information with physical layer or higher layers information,such as network layer,transmission layer,to achieve global optimization.展开更多
Based on the latest research findings of 3GPP on network sharing,this paper introduces 4 solutions to WCDMA 3G network sharing:site sharing,common network sharing,geographically split network sharing,and radio access ...Based on the latest research findings of 3GPP on network sharing,this paper introduces 4 solutions to WCDMA 3G network sharing:site sharing,common network sharing,geographically split network sharing,and radio access network sharing.It also analyzes the key network sharing technologies,including the lu-Flex function in Release 5,the UTRAN sharing mechanism in the connected mode in Release 5 and the mechanism of network sharing support enhancement in Release 6.展开更多
This paper analyzes the communication business needs and application characteristics based on China's railway operation scenarios.Focusing on the specific needs of railways,the 5G-Railway(5G-R)system adds railway-...This paper analyzes the communication business needs and application characteristics based on China's railway operation scenarios.Focusing on the specific needs of railways,the 5G-Railway(5G-R)system adds railway-specific functional network elements on the basis of general architecture.In terms of system networking,it focuses on the innovative key technologies of 5G-R core network and wireless network networking to adapt to the railway management mechanism and reliability requirements.It analyzes the technical optimization and innovation of 5G-R railway common equipment in terms of redundancy mode,function sinking,fault detection and reversal mechanism,etc.;5G-R wireless network adopts the same-site equipment redundancy mode,and the paper analyzes the technological innovation of RRU redundancy,BBU redundancy and PCI planning,etc.;it also highlights the benefits of the train-ground integrated transmission system,including reduced roof antennas,decoupling of services and communication,unified spatial and temporal benchmarks,and cost savings.展开更多
Rapid advancement in science and technology has seen computer network technology being upgraded constantly, and computer technology, in particular, has been applied more and more extensively, which has brought conveni...Rapid advancement in science and technology has seen computer network technology being upgraded constantly, and computer technology, in particular, has been applied more and more extensively, which has brought convenience to people’s lives. The number of people using the internet around the globe has also increased significantly, exerting a profound influence on artificial intelligence. Further, the constant upgrading and development of artificial intelligence has led to the continuous innovation and improvement of computer technology. Countries around the world have also registered an increase in investment, paying more attention to artificial intelligence. Through an analysis of the current development situation and the existing applications of artificial intelligence, this paper explicates the role of artificial intelligence in the face of the unceasing expansion of computer network technology.展开更多
Background:Risk substances in cosmetics have long been associated with adverse reactions.However,as risk substances become more concealed and diversified,conventional targeted analysis methods are no longer sufficient...Background:Risk substances in cosmetics have long been associated with adverse reactions.However,as risk substances become more concealed and diversified,conventional targeted analysis methods are no longer sufficient to meet regulatory requirements.Objective:To construct a rapid and effective non-targeted screening method for the identification of risk substances,and to provide a high-throughput method for toxicity assessment.Methods:Molecular networking was utilized for the non-targeted screening of risk substances in facial skincare products,and the toxicity of these risk substances was evaluated through molecular docking and quantitative structure-activity relationship(QSAR)models.Results:Through molecular networking,we identified seven known prohibited ingredients,six of which were confirmed using standard substances.In addition,17 potential risk substances were discovered within molecular clusters containing prohibited ingredients,including antibiotics,antihistamines,and phthalates,etc.Notably,chloramphenicol base and N-desmethyl chlorpheniramine exhibited stronger binding affinity to keratin 5/14 than chloramphenicol and chlorpheniramine through molecular docking,respectively.Additionally,toxicity prediction results indicated that the carcinogenicity of antibiotics presented gender differences in mice and rats,and two chlorpheniramine derivatives also showed carcinogenicity in mice.Moreover,of the 24 compounds,11 showed skin sensitization,while 14 caused skin irritation.Furthermore,half of these compounds demonstrated potential developmental toxicity,and only 4-nitrobenzenethiol was found to be mutagenic.Conclusion:In this study,we developed a visualization strategy for non-targeted screening of risk substances and a high-throughput method for initial toxicity assessment of risk substances.展开更多
Normal-pressure shale gas is an important object of shale gas reserves and production increasewith broad resource prospects in China,but its large-scale benefit development is still confronted with technical bottlenec...Normal-pressure shale gas is an important object of shale gas reserves and production increasewith broad resource prospects in China,but its large-scale benefit development is still confronted with technical bottlenecks.To promote the large-scale benefit development of normal-pressure shale gas,this paper systematically sorts out and summarizes the research achievements and technological progresses related to normal-pressure shale gas from the aspects of accumulation mechanism,enrichment theory,percolation mechanism,development technology,and low-cost engineering technology,and points out the difficulties and challenges to the benefit development of normal-pressure shale gas in the complex structure zones of southern China,by taking the shale gas in the Southeast Chongqing Area of the Sichuan Basin as the research object.In addition,the research direction of normal-pressure shale gas exploration and development is discussed in terms of sweet spot selection,development technology policy,low-cost drilling technology and high-efficiency fracturing technology.And the following research results are obtained.First,the accumulation mechanism of normal-pressure shale gas is clarified from the perspective of geological exploration theory;the hydrocarbon accumulation model of generation,expulsion,retention and accumulation is established;the enrichment theory of“three-factor controlling reservoir”is put forward;and the comprehensive sweetspot target evaluation system is formed.Second,as for development technology,the development technology policies of“multiple series of strata,variable well spacing,long horizontal section,small included angle,low elevation difference,strong stimulation and pressure difference controlling”are formulated.Third,as for drilling engineering,the optimal fast drilling and completion technology with“secondary structureþradical parameterþintegrated guidanceþunpressured leak-proof cementing”as the core is formed.Fourth,as for fracturing engineering,the low-cost and high-efficiency fracturing technology with“multi-cluster small-stageþlimited-entry perforatingþdouble temporary blockingþhigh-intensity sand injectionþfully electric”as the core is formed.Fifth,normal-pressure shale gas is characterized by complex geological conditions,low pressure coefficient and gas content,poor resource endowment and so on,but its resource utilization still faces a series of challenges,such as uncertain productivity construction positions,low single-well productivity and ultimate recoverable reserve,high investment cost and poor economic benefit.In conclusion,the key research directions to realize the large-scale benefit development of low-grade normal-pressure shale gas are to deepen the research on the enrichment and high yield mechanism and sweet spot selection of normal-pressure shale gas,strengthen the research on the benefit development technology policy based on percolation mechanism and the key technologies for low-cost drilling,accelerate the research and devel-opment of the key technologies for low-cost and high-efficiency fracturing,and implement cost reduction and efficiency improvement continuously.展开更多
Satellite-terrestrial networks have garnered significant attention in recent years and are extensively applied in intelligent transportation and emergency rescue.This paper provides a comprehensive review of the lates...Satellite-terrestrial networks have garnered significant attention in recent years and are extensively applied in intelligent transportation and emergency rescue.This paper provides a comprehensive review of the latest research advancements in satellite-terrestrial integrated network(STIN)technologies from a network perspective,dividing STIN technologies into three categories according to network service flows—namely,topology maintenance,network routing,and orchestration transmission technologies.Furthermore,a novel network-layer perspective is considered to examine the applications of STINs across various domains,along with related frameworks,platforms,simulators,and datasets.Finally,this paper explores the mainstream research directions in STIN technologies,with an innovative focus on the network layer.It reviews the existing literature,outlines future trends,and discusses opportunities for collaboration with related fields.展开更多
To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybr...To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybrid and dual-teacher classroom model.Based on big data and online platforms,this study constructs a music teaching resource system that integrates online micro-lessons,real-time interaction,virtual choirs,collaborative composition,and learning behavior tracking to enhance the openness and personalization of teaching.Through comparative experiments,the study focuses on changes in student knowledge acquisition,musical skills,learning interest,and classroom engagement.Results show that the experimental group significantly outperforms the control group in terms of improvement in knowledge test scores,rhythm and pitch performance,task completion rate,and scores on the learning motivation questionnaire.Differences are particularly prominent in interaction frequency and the expressiveness of the work.The study shows that Group A demonstrates significant improvement in all three dimensions:interest increases from 3.1 to 4.2;autonomous learning motivation increases from 3.0 to 4.1;emotional engagement increases from 3.2 to 4.3,demonstrating strong positive effects.Experimental Group B shows the greatest improvement,with interest increasing from 3.0 to 4.5,autonomous learning motivation from 2.9 to 4.4,and emotional engagement from 3.1 to 4.6,indicating the most significant improvements in learning attitudes and emotions.展开更多
This paper takes a college English Academic teaching mode based on computer network technology as the research object.Firstly,the Challenges of Academic English writing for Chinese College Students are analyzed.Then t...This paper takes a college English Academic teaching mode based on computer network technology as the research object.Firstly,the Challenges of Academic English writing for Chinese College Students are analyzed.Then the advantages of college English autonomous learning dynamic teaching mode under computer network technology are discussed.After that,it demonstrates a case study of a Computer-assisted English teaching model in academic writing.展开更多
文摘It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications.As a standard of broadband wireless access systems,IEEE 802.16 adopts Orthogonal Frequency Division Multiplexing(OFDM)and multi-modulation/coding techniques at the physical layer,combines contend and pre-contract mechanisms at the Medium Access Control(MAC)layer.Based on the QoS-related concepts such as connection and service flow,IEEE 802.16 optimizes network entry and initialization,and frame format in order to improve network throughput,reduce network delay,and increase the flexibility of network configuration.Based on IEEE 802.16,WiMAX adopts Point-to-Multipoint(PMP)network topology to realize flexible networking.It is a typical application technology of broadband wireless access systems.
文摘With the continuous enrichment of mobile communication application scenarios in the future, the traditional macro-cellular-based mobile communication network architecture will be difficult to meet the explosive growth in demand for communications services.
基金funded by Special Standardization Foundation of the Science and Technology Commission of Shanghai Municipality under Grant 07DZ05018the Natural Science Foundation of Shanghai Municipality under Grant 07ZR14104
文摘The continuous increase of data transmission density in wireless mobile communications has posed a challenge to the system performance of Wireless Mesh Networks(WMNs).There is a rule for wireless Ad hoc networks that the average node capacity decreases while the number of nodes increases,so it is hard to establish a large-scale wireless Mesh network.Network scalability is very important for enhancing the adaptive networking capability of the wireless Mesh network.This article discusses key scalability technologies for Mesh Base Stations(BSs)and Mesh Mobile Stations(MSs),such as channel allocation,intelligent routing,multi-antenna,node classification,Quality of Service(QoS)differentiation and cooperative transmission.
文摘When computers and communication devices are available everywhere in the future,the categories of communication will expand to cover not only the man-man and the man-machine,but also the machine-machine(M2M)communication.Someday,the traffic generated by machines will greatly exceed those of man-machine and man-man applications.Large numbers of M2M applications will need various wireless networks to support them.This paper introduces the characteristics,advantages and disadvantages of the currently available various wireless network technologies,including WiFi,Bluetooth,ZigBee,passive RFID and the 802.15 standard networks.
文摘The network integration provides users with a new network with long connection time and a high data rate when needed,but it also brings the defects of all the networks that integrate together into the integrated network.This will cause all kinds of existing and some new security problems in the operation of the integrated network.A complete protection based on recovery is proposed in the paper.It uses the public-key algorithm to authorize and private-key algorithm to encrypt the communicating data.This solution can provide the system with reliable security,and avoid Denial of Service(DoS)of the user.This solution has been proposed lately,and we should further identify the correct action of all the layers and figure out how to react when a legal node is framed by multiple malicious nodes.
基金This work was funded by the National Natural Science Foundation of China under Grant60473090.
文摘The Peer-to-Peer(P2P)network traffic identification technology includes Transport Layer Identification(TLI)and Deep Packet Inspection(DPI)methods.By analyzing packets of the transport layer and the traffic characteristic in the P2P system,TLI can identify whether or not the network data flow belongs to the P2P system.The DPI method adopts protocol analysis technology and reverting technology.It picks up data from the P2P application layer and analyzes the characteristics of the payload to judge if the network traffic belongs to P2P applications.Due to its accuracy,robustness and classifying ability,DPI is the main method used to identify P2P traffic.Adopting the advantages of TLI and DPI,a precise and efficient technology for P2P network traffic identification can be designed.
文摘Networking is the core area of national strategic emerging industry development of information industry; it will play an important role in national economic development. Currently, it is hot issue of global research at home and abroad regardless of the mention of its development of a national strategic level, it is called the third wave of the world information industry following the computer, and internet.
文摘The 21 st century is an era of information technology, network technology is in all areas of life and production and also higher education administration began to apply network technology and network management. However, in the rapid development of information technology today, due to network with their own information technology, high-speed, information-based features are widely used in educational management in universities, so that some common problems on the network has infiltrated into university education management, making College Educational management in the New face new problems and challenges. Through the influence of network technology for Higher Education Management of the research on network technology we make a few constructive suggestions on education management application and Universities.
文摘To find out an effective way to improve higher vocational college students＇ reading abilities, the author designs an experiment that applying the multimedia and network technologies in the higher vocational public English reading teaching to test whether the multimedia teaching mode is more effective than the traditional teaching mode in enhancing vocational college students＇ reading performance. The contrastive experiment is done for one semester and the experiment shows that if applying multimedia and network technologies in higher vocational public English reading teaching, creating authentic language environment, it can improve the classroom efficiency, improve students＇ English reading ability, thus forming the student-centered modem higher vocational public English reading teaching mode,
基金supported by the National Natural Science Foundation of China under Grant No.60772110.
文摘As a smart spectrum sharing technology,Cognitive Radio(CR)is becoming a hot topic in the field of wireless telecommunications.Besides providing traditional services,the cognitive radio network Media Access Control(MAC)layer is required to perform an entirely new set of functions for effective reusing spectrum opportunity,without causing any harmful interference to incumbents.Spectrum sensing management selects and optimizes sensing strategies and parameters by the selection of sensing mode,sensing period,sensing time,sensing channel,and sensing quiet period.Access control avoids collision with primary users mainly by cooperation access and transparent access.Dynamic spectrum allocation optimizes the allocation of uncertain spectrum for binary interference model and accumulative interference model.Security mechanism adds authentication and encryption mechanisms to MAC frame to defense MAC layer security attacks.Cross-layer design combines MAC layer information with physical layer or higher layers information,such as network layer,transmission layer,to achieve global optimization.
文摘Based on the latest research findings of 3GPP on network sharing,this paper introduces 4 solutions to WCDMA 3G network sharing:site sharing,common network sharing,geographically split network sharing,and radio access network sharing.It also analyzes the key network sharing technologies,including the lu-Flex function in Release 5,the UTRAN sharing mechanism in the connected mode in Release 5 and the mechanism of network sharing support enhancement in Release 6.
文摘This paper analyzes the communication business needs and application characteristics based on China's railway operation scenarios.Focusing on the specific needs of railways,the 5G-Railway(5G-R)system adds railway-specific functional network elements on the basis of general architecture.In terms of system networking,it focuses on the innovative key technologies of 5G-R core network and wireless network networking to adapt to the railway management mechanism and reliability requirements.It analyzes the technical optimization and innovation of 5G-R railway common equipment in terms of redundancy mode,function sinking,fault detection and reversal mechanism,etc.;5G-R wireless network adopts the same-site equipment redundancy mode,and the paper analyzes the technological innovation of RRU redundancy,BBU redundancy and PCI planning,etc.;it also highlights the benefits of the train-ground integrated transmission system,including reduced roof antennas,decoupling of services and communication,unified spatial and temporal benchmarks,and cost savings.
文摘Rapid advancement in science and technology has seen computer network technology being upgraded constantly, and computer technology, in particular, has been applied more and more extensively, which has brought convenience to people’s lives. The number of people using the internet around the globe has also increased significantly, exerting a profound influence on artificial intelligence. Further, the constant upgrading and development of artificial intelligence has led to the continuous innovation and improvement of computer technology. Countries around the world have also registered an increase in investment, paying more attention to artificial intelligence. Through an analysis of the current development situation and the existing applications of artificial intelligence, this paper explicates the role of artificial intelligence in the face of the unceasing expansion of computer network technology.
基金supported by the Scientific and technological innovation project of Guangdong Provincial Drug Administration(ZA20230069,2024ZDZ04)the Science and Technology Plan Project of Guangdong Provincial(2023A1111120025).
文摘Background:Risk substances in cosmetics have long been associated with adverse reactions.However,as risk substances become more concealed and diversified,conventional targeted analysis methods are no longer sufficient to meet regulatory requirements.Objective:To construct a rapid and effective non-targeted screening method for the identification of risk substances,and to provide a high-throughput method for toxicity assessment.Methods:Molecular networking was utilized for the non-targeted screening of risk substances in facial skincare products,and the toxicity of these risk substances was evaluated through molecular docking and quantitative structure-activity relationship(QSAR)models.Results:Through molecular networking,we identified seven known prohibited ingredients,six of which were confirmed using standard substances.In addition,17 potential risk substances were discovered within molecular clusters containing prohibited ingredients,including antibiotics,antihistamines,and phthalates,etc.Notably,chloramphenicol base and N-desmethyl chlorpheniramine exhibited stronger binding affinity to keratin 5/14 than chloramphenicol and chlorpheniramine through molecular docking,respectively.Additionally,toxicity prediction results indicated that the carcinogenicity of antibiotics presented gender differences in mice and rats,and two chlorpheniramine derivatives also showed carcinogenicity in mice.Moreover,of the 24 compounds,11 showed skin sensitization,while 14 caused skin irritation.Furthermore,half of these compounds demonstrated potential developmental toxicity,and only 4-nitrobenzenethiol was found to be mutagenic.Conclusion:In this study,we developed a visualization strategy for non-targeted screening of risk substances and a high-throughput method for initial toxicity assessment of risk substances.
基金supported by the National Science and Technology Major Project of China"Demonstrative project of normal-pressure shale gas exploration and development in the Pengshui area"(No.2016ZX05061)the Sinopec Scientific Research Projects"Evaluation of normal-pressure shale gas enrichment and production mechanisms and targets in Nan-chuan-Wulong"(No.P21087-6)"Evaluation of shale gas enrichment and targets in the East China exploration area in Sichuan Basin and its periphery"(No.P20059-6).
文摘Normal-pressure shale gas is an important object of shale gas reserves and production increasewith broad resource prospects in China,but its large-scale benefit development is still confronted with technical bottlenecks.To promote the large-scale benefit development of normal-pressure shale gas,this paper systematically sorts out and summarizes the research achievements and technological progresses related to normal-pressure shale gas from the aspects of accumulation mechanism,enrichment theory,percolation mechanism,development technology,and low-cost engineering technology,and points out the difficulties and challenges to the benefit development of normal-pressure shale gas in the complex structure zones of southern China,by taking the shale gas in the Southeast Chongqing Area of the Sichuan Basin as the research object.In addition,the research direction of normal-pressure shale gas exploration and development is discussed in terms of sweet spot selection,development technology policy,low-cost drilling technology and high-efficiency fracturing technology.And the following research results are obtained.First,the accumulation mechanism of normal-pressure shale gas is clarified from the perspective of geological exploration theory;the hydrocarbon accumulation model of generation,expulsion,retention and accumulation is established;the enrichment theory of“three-factor controlling reservoir”is put forward;and the comprehensive sweetspot target evaluation system is formed.Second,as for development technology,the development technology policies of“multiple series of strata,variable well spacing,long horizontal section,small included angle,low elevation difference,strong stimulation and pressure difference controlling”are formulated.Third,as for drilling engineering,the optimal fast drilling and completion technology with“secondary structureþradical parameterþintegrated guidanceþunpressured leak-proof cementing”as the core is formed.Fourth,as for fracturing engineering,the low-cost and high-efficiency fracturing technology with“multi-cluster small-stageþlimited-entry perforatingþdouble temporary blockingþhigh-intensity sand injectionþfully electric”as the core is formed.Fifth,normal-pressure shale gas is characterized by complex geological conditions,low pressure coefficient and gas content,poor resource endowment and so on,but its resource utilization still faces a series of challenges,such as uncertain productivity construction positions,low single-well productivity and ultimate recoverable reserve,high investment cost and poor economic benefit.In conclusion,the key research directions to realize the large-scale benefit development of low-grade normal-pressure shale gas are to deepen the research on the enrichment and high yield mechanism and sweet spot selection of normal-pressure shale gas,strengthen the research on the benefit development technology policy based on percolation mechanism and the key technologies for low-cost drilling,accelerate the research and devel-opment of the key technologies for low-cost and high-efficiency fracturing,and implement cost reduction and efficiency improvement continuously.
基金support from the National Key Research and Development Program of China(2024YFB3108400)the Hubei Province Key Research and Development Program(2024BAB051).
文摘Satellite-terrestrial networks have garnered significant attention in recent years and are extensively applied in intelligent transportation and emergency rescue.This paper provides a comprehensive review of the latest research advancements in satellite-terrestrial integrated network(STIN)technologies from a network perspective,dividing STIN technologies into three categories according to network service flows—namely,topology maintenance,network routing,and orchestration transmission technologies.Furthermore,a novel network-layer perspective is considered to examine the applications of STINs across various domains,along with related frameworks,platforms,simulators,and datasets.Finally,this paper explores the mainstream research directions in STIN technologies,with an innovative focus on the network layer.It reviews the existing literature,outlines future trends,and discusses opportunities for collaboration with related fields.
文摘To address the widespread challenges of insufficient classroom participation,difficulty maintaining learning interest,and inaccurate learning outcome assessment in existing teaching models,this study introduces a hybrid and dual-teacher classroom model.Based on big data and online platforms,this study constructs a music teaching resource system that integrates online micro-lessons,real-time interaction,virtual choirs,collaborative composition,and learning behavior tracking to enhance the openness and personalization of teaching.Through comparative experiments,the study focuses on changes in student knowledge acquisition,musical skills,learning interest,and classroom engagement.Results show that the experimental group significantly outperforms the control group in terms of improvement in knowledge test scores,rhythm and pitch performance,task completion rate,and scores on the learning motivation questionnaire.Differences are particularly prominent in interaction frequency and the expressiveness of the work.The study shows that Group A demonstrates significant improvement in all three dimensions:interest increases from 3.1 to 4.2;autonomous learning motivation increases from 3.0 to 4.1;emotional engagement increases from 3.2 to 4.3,demonstrating strong positive effects.Experimental Group B shows the greatest improvement,with interest increasing from 3.0 to 4.5,autonomous learning motivation from 2.9 to 4.4,and emotional engagement from 3.1 to 4.6,indicating the most significant improvements in learning attitudes and emotions.
文摘This paper takes a college English Academic teaching mode based on computer network technology as the research object.Firstly,the Challenges of Academic English writing for Chinese College Students are analyzed.Then the advantages of college English autonomous learning dynamic teaching mode under computer network technology are discussed.After that,it demonstrates a case study of a Computer-assisted English teaching model in academic writing.
