This paper makes a brief introduction of the ecological environment, forestry achievements, and the existing questions of Jilin Province. The task of forest ecological network and eight questions demanding prompt solu...This paper makes a brief introduction of the ecological environment, forestry achievements, and the existing questions of Jilin Province. The task of forest ecological network and eight questions demanding prompt solution were discussed based on the present situation of forestry in Jilin Province. The author also made prospects for future application of bio-technique, infor-mation technology, new material technology and nuisance-free forest health technology in forest ecological network.展开更多
Osteocytes reside as three-dimensionally(3D) networked cells in the lacunocanalicular structure of bones and regulate bone and mineral homeostasis. Despite of their important regulatory roles, in vitro studies of os...Osteocytes reside as three-dimensionally(3D) networked cells in the lacunocanalicular structure of bones and regulate bone and mineral homeostasis. Despite of their important regulatory roles, in vitro studies of osteocytes have been challenging because:(1) current cell lines do not sufficiently represent the phenotypic features of mature osteocytes and(2) primary cells rapidly differentiate to osteoblasts upon isolation. In this study, we used a 3D perfusion culture approach to:(1) construct the 3D cellular network of primary murine osteocytes by biomimetic assembly with microbeads and(2) reproduce ex vivo the phenotype of primary murine osteocytes, for the first time to our best knowledge. In order to enable 3D construction with a sufficient number of viable cells, we used a proliferated osteoblastic population of healthy cells outgrown from digested bone chips. The diameter of microbeads was controlled to:(1) distribute and entrap cells within the interstitial spaces between the microbeads and(2) maintain average cell-to-cell distance to be about 19 mm. The entrapped cells formed a 3D cellular network by extending and connecting their processes through openings between the microbeads. Also, with increasing culture time, the entrapped cells exhibited the characteristic gene expressions(SOST and FGF23) and nonproliferative behavior of mature osteocytes. In contrast, 2D-cultured cells continued their osteoblastic differentiation and proliferation. This 3D biomimetic approach is expected to provide a new means of:(1) studying flow-induced shear stress on the mechanotransduction function of primary osteocytes,(2) studying physiological functions of 3D-networked osteocytes with in vitro convenience,and(3) developing clinically relevant human bone disease models.展开更多
In this letter,Constructive Neural Networks (CNN) is used in large-scale data mining. By introducing the principle and characteristics of CNN and pointing out its deficiencies,fuzzy theory is adopted to improve the co...In this letter,Constructive Neural Networks (CNN) is used in large-scale data mining. By introducing the principle and characteristics of CNN and pointing out its deficiencies,fuzzy theory is adopted to improve the covering algorithms. The threshold of covering algorithms is redefined. "Extended area" for test samples is built. The inference of the outlier is eliminated. Furthermore,"Sphere Neighborhood (SN)" are constructed. The membership functions of test samples are given and all of the test samples are determined accordingly. The method is used to mine large wireless monitor data (about 3×107 data points),and knowledge is found effectively.展开更多
This paper introduces the selection and scheme demonstration of higher voltage class in Northwest ChinaPower Network, and conclusions made by main research institutes and experts’ comments.[
The research advances on 3G CDMA standards are outlined and the network architecture and networking characteristics of CD- MA2000 1x EV-DO and CDMA2000 1x EV-DV are described.Em- phasis is put on the key technical iss...The research advances on 3G CDMA standards are outlined and the network architecture and networking characteristics of CD- MA2000 1x EV-DO and CDMA2000 1x EV-DV are described.Em- phasis is put on the key technical issues that may occur when China Unicom upgrades CDMA2000 1x to CDMA2000 1x EV-DO.展开更多
The technical characters of mobile agent (MA) originated in the distributional artificial intelligence domain is introduced. A network management construction based on agent (NMCA) is then proposed. The NMCA struc...The technical characters of mobile agent (MA) originated in the distributional artificial intelligence domain is introduced. A network management construction based on agent (NMCA) is then proposed. The NMCA structure features are elaborated in detail. A prototype design of NMCA is given by using the jKQML programming. The establishment of NMCA platform will be helpful to reduce the correspondence load of network management and improves the efficiency and the expansion ability of network management systems.展开更多
Blockchain merges technology with the Internet of Things(IoT)for addressing security and privacy-related issues.However,conventional blockchain suffers from scalability issues due to its linear structure,which increas...Blockchain merges technology with the Internet of Things(IoT)for addressing security and privacy-related issues.However,conventional blockchain suffers from scalability issues due to its linear structure,which increases the storage overhead,and Intrusion detection performed was limited with attack severity,leading to performance degradation.To overcome these issues,we proposed MZWB(Multi-Zone-Wise Blockchain)model.Initially,all the authenticated IoT nodes in the network ensure their legitimacy by using the Enhanced Blowfish Algorithm(EBA),considering several metrics.Then,the legitimately considered nodes for network construction for managing the network using Bayesian-Direct Acyclic Graph(B-DAG),which considers several metrics.The intrusion detection is performed based on two tiers.In the first tier,a Deep Convolution Neural Network(DCNN)analyzes the data packets by extracting packet flow features to classify the packets as normal,malicious,and suspicious.In the second tier,the suspicious packets are classified as normal or malicious using the Generative Adversarial Network(GAN).Finally,intrusion scenario performed reconstruction to reduce the severity of attacks in which Improved Monkey Optimization(IMO)is used for attack path discovery by considering several metrics,and the Graph cut utilized algorithm for attack scenario reconstruction(ASR).UNSW-NB15 and BoT-IoT utilized datasets for the MZWB method simulated using a Network simulator(NS-3.26).Compared with previous performance metrics such as energy consumption,storage overhead accuracy,response time,attack detection rate,precision,recall,and F-measure.The simulation result shows that the proposed MZWB method achieves high performance than existing works.展开更多
The intersection of the Industrial Internet of Things(IIoT)and artificial intelligence(AI)has garnered ever-increasing attention and research interest.Nevertheless,the dilemma between the strict resource-constrained n...The intersection of the Industrial Internet of Things(IIoT)and artificial intelligence(AI)has garnered ever-increasing attention and research interest.Nevertheless,the dilemma between the strict resource-constrained nature of IIoT devices and the extensive resource demands of AI has not yet been fully addressed with a comprehensive solution.Taking advantage of the lightweight constructive neural network(LightGCNet)in developing fast learner models for IIoT,a convex geometric constructive neural network with a low-complexity control strategy,namely,ConGCNet,is proposed in this article via convex optimization and matrix theory,which enhances the convergence rate and reduces the computational consumption in comparison with LightGCNet.Firstly,a low-complexity control strategy is proposed to reduce the computational consumption during the hidden parameters training process.Secondly,a novel output weights evaluated method based on convex optimization is proposed to guarantee the convergence rate.Finally,the universal approximation property of ConGCNet is proved by the low-complexity control strategy and convex output weights evaluated method.Simulation results,including four benchmark datasets and the real-world ore grinding process,demonstrate that ConGCNet effectively reduces computational consumption in the modelling process and improves the model’s convergence rate.展开更多
This article focuses on reviewing the technologies of persistent scatterer interferometry (PSI), which has been often used to monitor the deformation of Earth surface. Three critical steps in the implementation of P...This article focuses on reviewing the technologies of persistent scatterer interferometry (PSI), which has been often used to monitor the deformation of Earth surface. Three critical steps in the implementation of PSI were introduced, i.e., (1) detection of persistent scatterer (PS), (2) construction of PS network, and (3) PSI modeling and solution. Finally, the main problems and outlooks on the PSI technique are discussed and given.展开更多
The significant achievements in construction and upgrade of China’s urban grids in the past two years and more are enumerated with respect to scale of grids, configuration of medium-and high-voltage grids, technical ...The significant achievements in construction and upgrade of China’s urban grids in the past two years and more are enumerated with respect to scale of grids, configuration of medium-and high-voltage grids, technical and localizing level of equipment, as well as social and economic benefits. At the same time, the new tasks for the year 2001 is put forth for volume of investment to be completed, projects progressing and operating benefit indexes, etc.展开更多
Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model t...Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model that distinguishes five crucial perspectives on a creative act(actors,audience,artefacts,actions and affordances).The paper will outline a linguistic version of this model that adopts Construction Grammar as its theoretical foundation.The resulting"5C model of constructional creativity"argues that the central elements of linguistic creativity are constructors,co-constructors,constructs,constructional blending and the constructional network.展开更多
Objective:This study explored the multicomponent,multitarget,and multipathway mechanism of Danhe granules(DG)against hyperlipidemia through network pharmacology.The relevant targets and pathways were verified by preli...Objective:This study explored the multicomponent,multitarget,and multipathway mechanism of Danhe granules(DG)against hyperlipidemia through network pharmacology.The relevant targets and pathways were verified by preliminary experiments.Methods:The active components of DG were selected by TCMSP and TCMIP database,and the component-target network diagram was constructed by Cytoscape 3.7.1.The protein–protein interaction network of targets was constructed and core targets were screened out by STRING11.0 database.Metascape database and Cytoscape 3.7.1 were used to enrich the target and establish a hyperlipidemia model in Sprague-Dawley(SD)rats to detect blood lipid and oxidative stress indexes and observed pathological changes of aorta by H and E staining.Results:The results showed that a total of seven active components of DG were screened out,including quercetin,sitosterol,luteolin,kaempferol,etc.There were 127 corresponding targets,including AKT1,tumor necrosis factor,TP53,interleukin-6,RELA,vascular endothelial growth factor,superoxide dismutases,and catalase.It is mainly involved in biological processes such as drug response,regulation of apoptosis,redox reaction,and lipid reaction.There were 573 signal pathways corresponding to the target,including HIF-1 signal pathway,TNF signal pathway,VEGF signal pathway,nonalcoholic fatty liver disease,etc.The experiment verified that DG can reduce the blood lipid of SD rats by regulating the process of oxidative stress.Conclusions:This study made a preliminary study on the pharmacological mechanism of DG against hyperlipidemia and laid the foundation for the research and development of new drugs and subsequent in-depth research.展开更多
The article briefly introduces the three stages that China Post experienced and the circumstances of the fundamental network construction, focusing on introducing the three sorts of services based on postal comprehens...The article briefly introduces the three stages that China Post experienced and the circumstances of the fundamental network construction, focusing on introducing the three sorts of services based on postal comprehensive computer network's applicable software system : postal financial service ; traditional service electrified ; electronic postal service. Finally the thinking for future China Post's informationizing constructing is put forward.展开更多
Presently,blockchain technology has been widely applied in various application domains such as the Internet of Things(IoT),supply chain management,healthcare,etc.So far,there has been much confusion about whether bloc...Presently,blockchain technology has been widely applied in various application domains such as the Internet of Things(IoT),supply chain management,healthcare,etc.So far,there has been much confusion about whether blockchain performs with scale,and admittedly,a lack of information about best practices that can improve the performance and scale.This paper proposes a novel blockchain network construction methodology to improve the performance of Hyperledger Fabric.As a highly scalable permissioned blockchain platform,Hyperledger Fabric supports a wide range of enterprise use cases from finance to governance.A comprehensive evaluation is performed by observing various configurable network components that can affect the blockchain performance.To demonstrate the significance of the proposed methodology,we set up the experiment environment for the baseline and the test network using optimized parameters,respectively.The experimental results indicate that the test network's performance is enhanced effectively compared to the baseline in transaction throughput and transaction latency.展开更多
Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbo...Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbon fiber(C_(f))@Fe_(3)O_(4) nanocomposites obtained by the electrostatic spinning and reflow method,C_(f)@FeS_(2)nanocomposite was successfully prepared during a further hydrothermal process.The products exhibit excellent electromagnetic wave absorption performances with a minimum reflection loss(RLmin)of-54.11 dB at 2.13 mm matching thickness.At the same time,the optimal effective absorption bandwidth(EAB)value of 6.04 GHz at a thickness of 1.98 mm covers the whole Ku band,suggesting its excellent electromagnetic wave absorption performances.In addition,the interlaced network structure constructed by carbon fiber,outstanding conductivity of FeS_(2)nanoparticles,and interfacial polarization from hetero-structure play significant parts in enhancing the electromagnetic parameters and absorption performances.All these results suggest that the C_(f)@FeS_(2)nanocomposites can be taken as a new electromagnetic wave-absorbing material under their low density,simple craft,and strong absorption characteristics.展开更多
in this poper the unbalance of development level in China's postal communication is discussed,classified into four types by Cluster Analysis Method, and the suggestion on postal service and postal network based on...in this poper the unbalance of development level in China's postal communication is discussed,classified into four types by Cluster Analysis Method, and the suggestion on postal service and postal network based on the different conditions of each type is made.展开更多
文摘This paper makes a brief introduction of the ecological environment, forestry achievements, and the existing questions of Jilin Province. The task of forest ecological network and eight questions demanding prompt solution were discussed based on the present situation of forestry in Jilin Province. The author also made prospects for future application of bio-technique, infor-mation technology, new material technology and nuisance-free forest health technology in forest ecological network.
基金the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (1R21AR065032 to W.Y.L and J.Z.)the National Science Foundation (DMR 1409779 to W.Y.L and J.Z.)
文摘Osteocytes reside as three-dimensionally(3D) networked cells in the lacunocanalicular structure of bones and regulate bone and mineral homeostasis. Despite of their important regulatory roles, in vitro studies of osteocytes have been challenging because:(1) current cell lines do not sufficiently represent the phenotypic features of mature osteocytes and(2) primary cells rapidly differentiate to osteoblasts upon isolation. In this study, we used a 3D perfusion culture approach to:(1) construct the 3D cellular network of primary murine osteocytes by biomimetic assembly with microbeads and(2) reproduce ex vivo the phenotype of primary murine osteocytes, for the first time to our best knowledge. In order to enable 3D construction with a sufficient number of viable cells, we used a proliferated osteoblastic population of healthy cells outgrown from digested bone chips. The diameter of microbeads was controlled to:(1) distribute and entrap cells within the interstitial spaces between the microbeads and(2) maintain average cell-to-cell distance to be about 19 mm. The entrapped cells formed a 3D cellular network by extending and connecting their processes through openings between the microbeads. Also, with increasing culture time, the entrapped cells exhibited the characteristic gene expressions(SOST and FGF23) and nonproliferative behavior of mature osteocytes. In contrast, 2D-cultured cells continued their osteoblastic differentiation and proliferation. This 3D biomimetic approach is expected to provide a new means of:(1) studying flow-induced shear stress on the mechanotransduction function of primary osteocytes,(2) studying physiological functions of 3D-networked osteocytes with in vitro convenience,and(3) developing clinically relevant human bone disease models.
基金Supported by the National Natural Science Foundation of China (No.60135010)partially supported by the National Grand Fundamental Research 973 Program of China (No.G1998030509).
文摘In this letter,Constructive Neural Networks (CNN) is used in large-scale data mining. By introducing the principle and characteristics of CNN and pointing out its deficiencies,fuzzy theory is adopted to improve the covering algorithms. The threshold of covering algorithms is redefined. "Extended area" for test samples is built. The inference of the outlier is eliminated. Furthermore,"Sphere Neighborhood (SN)" are constructed. The membership functions of test samples are given and all of the test samples are determined accordingly. The method is used to mine large wireless monitor data (about 3×107 data points),and knowledge is found effectively.
文摘This paper introduces the selection and scheme demonstration of higher voltage class in Northwest ChinaPower Network, and conclusions made by main research institutes and experts’ comments.[
文摘The research advances on 3G CDMA standards are outlined and the network architecture and networking characteristics of CD- MA2000 1x EV-DO and CDMA2000 1x EV-DV are described.Em- phasis is put on the key technical issues that may occur when China Unicom upgrades CDMA2000 1x to CDMA2000 1x EV-DO.
文摘The technical characters of mobile agent (MA) originated in the distributional artificial intelligence domain is introduced. A network management construction based on agent (NMCA) is then proposed. The NMCA structure features are elaborated in detail. A prototype design of NMCA is given by using the jKQML programming. The establishment of NMCA platform will be helpful to reduce the correspondence load of network management and improves the efficiency and the expansion ability of network management systems.
文摘Blockchain merges technology with the Internet of Things(IoT)for addressing security and privacy-related issues.However,conventional blockchain suffers from scalability issues due to its linear structure,which increases the storage overhead,and Intrusion detection performed was limited with attack severity,leading to performance degradation.To overcome these issues,we proposed MZWB(Multi-Zone-Wise Blockchain)model.Initially,all the authenticated IoT nodes in the network ensure their legitimacy by using the Enhanced Blowfish Algorithm(EBA),considering several metrics.Then,the legitimately considered nodes for network construction for managing the network using Bayesian-Direct Acyclic Graph(B-DAG),which considers several metrics.The intrusion detection is performed based on two tiers.In the first tier,a Deep Convolution Neural Network(DCNN)analyzes the data packets by extracting packet flow features to classify the packets as normal,malicious,and suspicious.In the second tier,the suspicious packets are classified as normal or malicious using the Generative Adversarial Network(GAN).Finally,intrusion scenario performed reconstruction to reduce the severity of attacks in which Improved Monkey Optimization(IMO)is used for attack path discovery by considering several metrics,and the Graph cut utilized algorithm for attack scenario reconstruction(ASR).UNSW-NB15 and BoT-IoT utilized datasets for the MZWB method simulated using a Network simulator(NS-3.26).Compared with previous performance metrics such as energy consumption,storage overhead accuracy,response time,attack detection rate,precision,recall,and F-measure.The simulation result shows that the proposed MZWB method achieves high performance than existing works.
文摘The intersection of the Industrial Internet of Things(IIoT)and artificial intelligence(AI)has garnered ever-increasing attention and research interest.Nevertheless,the dilemma between the strict resource-constrained nature of IIoT devices and the extensive resource demands of AI has not yet been fully addressed with a comprehensive solution.Taking advantage of the lightweight constructive neural network(LightGCNet)in developing fast learner models for IIoT,a convex geometric constructive neural network with a low-complexity control strategy,namely,ConGCNet,is proposed in this article via convex optimization and matrix theory,which enhances the convergence rate and reduces the computational consumption in comparison with LightGCNet.Firstly,a low-complexity control strategy is proposed to reduce the computational consumption during the hidden parameters training process.Secondly,a novel output weights evaluated method based on convex optimization is proposed to guarantee the convergence rate.Finally,the universal approximation property of ConGCNet is proved by the low-complexity control strategy and convex output weights evaluated method.Simulation results,including four benchmark datasets and the real-world ore grinding process,demonstrate that ConGCNet effectively reduces computational consumption in the modelling process and improves the model’s convergence rate.
基金supported by State Key Laboratory of Geodesy and Earth’s Dynamics(SKLGED2015-5-1-E)the Fundamental Research Funds for the Central Universities(2682015CX015)+1 种基金the National Natural Science Foundation of China(41474003)Program for Changjiang Scholars and Innovative Research Team in University(IRT13092)
文摘This article focuses on reviewing the technologies of persistent scatterer interferometry (PSI), which has been often used to monitor the deformation of Earth surface. Three critical steps in the implementation of PSI were introduced, i.e., (1) detection of persistent scatterer (PS), (2) construction of PS network, and (3) PSI modeling and solution. Finally, the main problems and outlooks on the PSI technique are discussed and given.
文摘The significant achievements in construction and upgrade of China’s urban grids in the past two years and more are enumerated with respect to scale of grids, configuration of medium-and high-voltage grids, technical and localizing level of equipment, as well as social and economic benefits. At the same time, the new tasks for the year 2001 is put forth for volume of investment to be completed, projects progressing and operating benefit indexes, etc.
文摘Creativity is a design feature of human language.This paper presents a cognitive model of verbal creativity that draws on insights from the psychological research into creativity-particularly Glaveanu's 5A model that distinguishes five crucial perspectives on a creative act(actors,audience,artefacts,actions and affordances).The paper will outline a linguistic version of this model that adopts Construction Grammar as its theoretical foundation.The resulting"5C model of constructional creativity"argues that the central elements of linguistic creativity are constructors,co-constructors,constructs,constructional blending and the constructional network.
基金supported by National Science and Technology Major Projects of China based on big data research and development of new Chinese medicines,DG preclinical efficacy,safety and related key technology research(No.2019ZX09201-004)。
文摘Objective:This study explored the multicomponent,multitarget,and multipathway mechanism of Danhe granules(DG)against hyperlipidemia through network pharmacology.The relevant targets and pathways were verified by preliminary experiments.Methods:The active components of DG were selected by TCMSP and TCMIP database,and the component-target network diagram was constructed by Cytoscape 3.7.1.The protein–protein interaction network of targets was constructed and core targets were screened out by STRING11.0 database.Metascape database and Cytoscape 3.7.1 were used to enrich the target and establish a hyperlipidemia model in Sprague-Dawley(SD)rats to detect blood lipid and oxidative stress indexes and observed pathological changes of aorta by H and E staining.Results:The results showed that a total of seven active components of DG were screened out,including quercetin,sitosterol,luteolin,kaempferol,etc.There were 127 corresponding targets,including AKT1,tumor necrosis factor,TP53,interleukin-6,RELA,vascular endothelial growth factor,superoxide dismutases,and catalase.It is mainly involved in biological processes such as drug response,regulation of apoptosis,redox reaction,and lipid reaction.There were 573 signal pathways corresponding to the target,including HIF-1 signal pathway,TNF signal pathway,VEGF signal pathway,nonalcoholic fatty liver disease,etc.The experiment verified that DG can reduce the blood lipid of SD rats by regulating the process of oxidative stress.Conclusions:This study made a preliminary study on the pharmacological mechanism of DG against hyperlipidemia and laid the foundation for the research and development of new drugs and subsequent in-depth research.
文摘The article briefly introduces the three stages that China Post experienced and the circumstances of the fundamental network construction, focusing on introducing the three sorts of services based on postal comprehensive computer network's applicable software system : postal financial service ; traditional service electrified ; electronic postal service. Finally the thinking for future China Post's informationizing constructing is put forward.
文摘Presently,blockchain technology has been widely applied in various application domains such as the Internet of Things(IoT),supply chain management,healthcare,etc.So far,there has been much confusion about whether blockchain performs with scale,and admittedly,a lack of information about best practices that can improve the performance and scale.This paper proposes a novel blockchain network construction methodology to improve the performance of Hyperledger Fabric.As a highly scalable permissioned blockchain platform,Hyperledger Fabric supports a wide range of enterprise use cases from finance to governance.A comprehensive evaluation is performed by observing various configurable network components that can affect the blockchain performance.To demonstrate the significance of the proposed methodology,we set up the experiment environment for the baseline and the test network using optimized parameters,respectively.The experimental results indicate that the test network's performance is enhanced effectively compared to the baseline in transaction throughput and transaction latency.
基金The work reported here was supported by the National Natural Science Foundation of China(Nos.52072196,52002199,52002200,and 52102106)the Major Basic Research Program of Natural Science Foundation of Shandong Province(No.ZR2020ZD09)+2 种基金the Natural Science Foundation of Shandong Province(Nos.ZR2019BEM042 and ZR2020QE063)the Innovation and Technology Program of Shandong Province(No.2020KJA004)the Taishan Scholars Program of Shandong Province(No.ts201511034).We express our grateful thanks to them for their financial support.
文摘Carbon-based electromagnetic wave absorbing materials(absorbers)adhered with metallic sulfide nanoparticles of good electrical conductivity attract increasing researchers’attention.In this study,on the basis of carbon fiber(C_(f))@Fe_(3)O_(4) nanocomposites obtained by the electrostatic spinning and reflow method,C_(f)@FeS_(2)nanocomposite was successfully prepared during a further hydrothermal process.The products exhibit excellent electromagnetic wave absorption performances with a minimum reflection loss(RLmin)of-54.11 dB at 2.13 mm matching thickness.At the same time,the optimal effective absorption bandwidth(EAB)value of 6.04 GHz at a thickness of 1.98 mm covers the whole Ku band,suggesting its excellent electromagnetic wave absorption performances.In addition,the interlaced network structure constructed by carbon fiber,outstanding conductivity of FeS_(2)nanoparticles,and interfacial polarization from hetero-structure play significant parts in enhancing the electromagnetic parameters and absorption performances.All these results suggest that the C_(f)@FeS_(2)nanocomposites can be taken as a new electromagnetic wave-absorbing material under their low density,simple craft,and strong absorption characteristics.
文摘in this poper the unbalance of development level in China's postal communication is discussed,classified into four types by Cluster Analysis Method, and the suggestion on postal service and postal network based on the different conditions of each type is made.