This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Ma...This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Many areas warrantfurther investigation and much optimization remains to be done. The fascinatingchemistry of phosphorus poses interesting hurdles but at the same time leavesample room for polymer scientists to exercise their creativity in designinginteresting biomaterials. As the mutual understanding between basic and clinicalscientists on the need of medical devices and the capabilities of these newbiomaterials expands, imaginative application of new biomaterials to other medi-cal applications can be expected.展开更多
Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualizatio...Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualization,ICIO networks with tremendous low-weight edges are too dense to show the substantial structure.These redundant edges,inevitably make the network data full of noise and eventually exert negative effects on Social Network Analysis(SNA).In this case,we need a method to filter such edges and obtain a sparser network with only the meaningful connections.Design/methodology/approach:In this paper,we propose two parameterless pruning algorithms from the global and local perspectives respectively,then the performance of them is examined using the ICIO table from different databases.Findings:The Searching Paths(SP)method extracts the strongest association paths from the global perspective,while Filtering Edges(FE)method captures the key links according to the local weight ratio.The results show that the FE method can basically include the SP method and become the best solution for the ICIO networks.Research limitations:There are still two limitations in this research.One is that the computational complexity may increase rapidly while processing the large-scale networks,so the proposed method should be further improved.The other is that much more empirical networks should be introduced to testify the scientificity and practicability of our methodology.Practical implications:The network pruning methods we proposed will promote the analysis of the ICIO network,in terms of community detection,link prediction,and spatial econometrics,etc.Also,they can be applied to many other complex networks with similar characteristics.Originality/value:This paper improves the existing research from two aspects,namely,considering the heterogeneity of weights and avoiding the interference of parameters.Therefore,it provides a new idea for the research of network backbone extraction.展开更多
In wireless sensor network,virtual backbone is a cost effective broadcasting method.Connected dominating set formation is proposed to construct a virtual backbone.However,it is NP-Hard to find a minimum connected domi...In wireless sensor network,virtual backbone is a cost effective broadcasting method.Connected dominating set formation is proposed to construct a virtual backbone.However,it is NP-Hard to find a minimum connected dominating set in an arbitrary graph.In this paper,based on cross-entropy method,we present a novel backbone formulation algorithm(BFA-CE)in wireless sensor network.In BFA-CE,a maximal independent set is got at first and nodes in the independent set are required to get their action sets.Based on those action sets,a backbone is generated with the cross-entropy method.Simulation results show that our algorithm can effectively reduce the size of backbone network within a reasonable message overhead,and it has lower average node degree.This approach can be potentially used in designing efficient broadcasting strategy or working as a backup routing of wireless sensor network.展开更多
A new polysaccharide was extracted and purified from the roots of Angelica sinensis (Oliv) Diels (ASD). Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The...A new polysaccharide was extracted and purified from the roots of Angelica sinensis (Oliv) Diels (ASD). Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The polysaccharide was made of → 1) Fruf(2→and→6) Glcp (l→as its backbone with highly branched structure. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the roots of the ASD.展开更多
An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here,which is different from a previously developed'spare parts'approach(Jones and Thirup,198...An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here,which is different from a previously developed'spare parts'approach(Jones and Thirup,1986;Claessens et al.,1989). In our procedure,the geometric restraint of angle N-CA-C is used to generate a list of polypeptide chains,and several filters are used later to select the best conformer.The most important filter is based upon the Ramachandran scatter plot of mainchain dihedral angles PHI and PSI.Results for all test cases are satisfactory,with more than 95%of peptide planes correctly reconstructed and the overall root-mean-square deviation less than 0.5 angstrom compared with the refined X-ray coordinates.展开更多
Ths paper,based on the principles of geometric self-similarity of fractal theory and some research results of rotein chemistry,improved the method of comput-ing protein fractal dimensions,and computed fractal dime...Ths paper,based on the principles of geometric self-similarity of fractal theory and some research results of rotein chemistry,improved the method of comput-ing protein fractal dimensions,and computed fractal dimensions of some protein back bone,secondary and assumed folding structures.The relationship between protein back-bone strucrural fractal dimensions and its spatial structures was investigated.The results indicated that protein backbone fractal dimensions not only have a close relation with protein secondary structure,but also with its folding.In addition,the folding of protein Polypeptide chains in 3-D space may be similar to the other macromolecular chain be haviour described by the self-avoiding walks(SAW)model.展开更多
Under the background of the rapid development of ground mobile communication,the advantages of high coverage,survivability,and flexibility of satellite communication provide air support to the construction of space in...Under the background of the rapid development of ground mobile communication,the advantages of high coverage,survivability,and flexibility of satellite communication provide air support to the construction of space information network.According to the requirements of the future space information communication,a software-defined Space-Air-Ground Integrated network architecture was proposed.It consisted of layered structure satellite backbone network,deep space communication network,the stratosphere communication network and the ground network.The Space-Air-Ground Integrated network was supported by the satellite backbone network.It provided data relay for the missions such as deep space exploration and controlled the deep-space spacecraft when needed.In addition,it safeguarded the anti-destructibility of stratospheric communication and assisted the stratosphere to supplement ground network communication.In this paper,algorithm requirements of the congestion control and routing of satellite backbone protocols for heterogeneous users’services were proposed.The algorithm requirements of distinguishing different service objects for the deep space communication and stratospheric communication network protocols were described.Considering the realistic demand for the dynamic coverage of the satellite backbone network and node cost,the multi-layer satellite backbone network architecture was constructed.On this basis,the proposed Software-defined Space-Air-Ground Integrated network architecture could be built as a large,scalable and efficient communication network that could be integrated into space,air,and ground.展开更多
Reaction of dimers of (R) thionophosphine sulfide (R = P - C6H4OMe,SMe ) with Co, (CO), yields the novel hexacobalt cluster [Co'(μ3, -S)2, (CO) 14 (μ4 -μ4- and the trinuclear clusterPSCH,)J 2' In 1, tw0 Co3...Reaction of dimers of (R) thionophosphine sulfide (R = P - C6H4OMe,SMe ) with Co, (CO), yields the novel hexacobalt cluster [Co'(μ3, -S)2, (CO) 14 (μ4 -μ4- and the trinuclear clusterPSCH,)J 2' In 1, tw0 Co3S(C0)7 units linked by a novel phosphido-thio1ato bifunc-tiona1 bridging p'-SPR ligand as backbone.展开更多
The modern telecommunication system is characterized by the rapid improvement of information and communication technologies, such as the improvement in the data rate, power consumption and Quality of Service (QoS). Ba...The modern telecommunication system is characterized by the rapid improvement of information and communication technologies, such as the improvement in the data rate, power consumption and Quality of Service (QoS). Based on this development, the next generation network (NGN) is shaped. The NGN is represented by a packet transport network demarcated functions and services. To provide transport functions in NGN, using Multi-Protocol Label Switching (MPLS) technology, there are two main problems, which are multipath routing and traffic distribution, which are what this paper works with. Accordingly, this paper proposes a solution to these two problems using optimization procedures to find the shortest path Dijkstra and Bellman-Ford, which is characterized by a high-speed-oriented selection of a single shortest path between the source and the destination, based on several selected criteria related to the optimal use of the network resources. Solving the information flow distribution problems in large number of nodes network applying salesman procedure or having NP-completeness, causes significant time delay, which means that the proposed solution is not suitable for real time applications. Accordingly, for real time applications, there is a need to move to other methods based on the use of several independent shortest paths.展开更多
The Metro Ethernet Forum(MEF) put forward the concept of Carrier Ethernet(CE) to improve Ethernet technology and make it a transmission convergence layer solution for Next Generation Network(NGN).Provider Backbone Tra...The Metro Ethernet Forum(MEF) put forward the concept of Carrier Ethernet(CE) to improve Ethernet technology and make it a transmission convergence layer solution for Next Generation Network(NGN).Provider Backbone Transport(PBT) is the result of the enhancement and improvement of the early Ethernet technologies and it is the new version of CE implementation technology and standard which is promising.Through studying the PBT-related technologies,PBT network structure,PBT advantages as the transmission convergence layer solution and its trend of future development,it is concluded that PBT can be used as the preferred technology of the transmission convergence layer in the NGN,though there are some problems to be solved for PBT.展开更多
To learn about the need of post-oriented education training of backbone civilian nurses,and to provide scientific evidence for the promotion of training. Methods The convenience sampling method was performed,and an an...To learn about the need of post-oriented education training of backbone civilian nurses,and to provide scientific evidence for the promotion of training. Methods The convenience sampling method was performed,and an anonymous survey on 324 nurses who participated in the "backbone civilian nurses training program"from September 2013 to October 2015 was carried out by using self-made questionnaire.Results(1)Among the 324 nurses,12. 04% of them volunteered to participate in the training and 87. 96%were sent by their departments.(2)More than 90% of training contents met their needs.(3)The training methods in demand included theoretical classroom teaching,clinical observation and probation,seminars,clinical management practice,clinical problem discussion and clinical nursing practice(4)The training period suggested by most nurses was about 2 to 4 weeks. Conclusion It is important to strengthen the significance of post-oriented education training and to improve the quality and capacity of civilian through scientific education design and practical training programs.展开更多
Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) an...Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.展开更多
This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns m...This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint, relay load constraint and gateway capacity constraint. Experimental results show that its performance is as good as that of the best of existing algorithms for the gateway placement problem. But, the new algorithm can be used for BWMNs that do not form one connected component, and it is easy to implement and use.展开更多
The 3-D structure of the β-adrenergic receptor with a molecular weight of 55,000 daltons is available from crystallographic data. Within one of the seven transmembrane ion channel helices in the β2-receptor, one loo...The 3-D structure of the β-adrenergic receptor with a molecular weight of 55,000 daltons is available from crystallographic data. Within one of the seven transmembrane ion channel helices in the β2-receptor, one loop of a helix ACADL has previously been proposed as the site that explains β2 activity (fights acute bronchitis) whereas ASADL in the β1-receptor at the corresponding site explains β1-activity (cardiac stimulation). The α-agonist responsible for this selective reaction is only 0.5% of the receptor molecular weight, and only 1.5% of the weight of the trans-membrane portion of the receptor. The understanding of the mechanism by which a small molecule on binding to a site on one single loop of a helix produces a specific agonist activity on an entire transmembrane ion channel is uncertain. A model of an α-helix is presented in which of pitch occurs at angles both smaller and larger than 180° n. Consequently, atomic coordinates in a peptide backbone α-helix match the data points of individual atom (and atom types) in the backbone. More precisely, eleven atoms in peptide backbone routinely equal one loop of a helix, instead of eleven amino acid residues equaling three loops of a helix;therefore, an α-helix can begin (or end) at any specific atom in a peptide backbone, not just at any specific amino acid. Wavefront Topology System and Finite Element Methods calculate this specific helical shape based only upon circumference, pitch, and phase. Only external forces which specifically affect circumference, pitch and/or phase (e.g. from agonist binding) can/will alter the shape of an α-helix.展开更多
1 Technical Features of ZTE’sDWDM SystemThe toll backbone wave division equipmentof ZXWM M900 backbone transmissionplatform is well designed forlarge-capacity optical transmission. It canfully satisfy the networking ...1 Technical Features of ZTE’sDWDM SystemThe toll backbone wave division equipmentof ZXWM M900 backbone transmissionplatform is well designed forlarge-capacity optical transmission. It canfully satisfy the networking and managementrequirements of diversified users and be fit forvarious toll backbone networks. The systemsupports up to 40 working wavelengths and up to400 Gb/s transmission capacity, and thewavelength selection and interval are in strictcompliance with ITU-T Recommendations. It展开更多
Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strat...Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.展开更多
文摘This review provides a glimpse of the potential of the biodegradable phos-phoryl-containing polymers in medical applications. Undoubtedly these polymerspossess unique properties that are yet to be fully understood. Many areas warrantfurther investigation and much optimization remains to be done. The fascinatingchemistry of phosphorus poses interesting hurdles but at the same time leavesample room for polymer scientists to exercise their creativity in designinginteresting biomaterials. As the mutual understanding between basic and clinicalscientists on the need of medical devices and the capabilities of these newbiomaterials expands, imaginative application of new biomaterials to other medi-cal applications can be expected.
基金support from National Natural Science Foundation of China(Grant No.71971006)Humanities and Social Science Foundation of Ministry of Education of the People’s Republic of China(Grant No.19YJCGJW014).
文摘Purpose:With the availability and utilization of Inter-Country Input-Output(ICIO)tables,it is possible to construct quantitative indices to assess its impact on the Global Value Chain(GVC).For the sake of visualization,ICIO networks with tremendous low-weight edges are too dense to show the substantial structure.These redundant edges,inevitably make the network data full of noise and eventually exert negative effects on Social Network Analysis(SNA).In this case,we need a method to filter such edges and obtain a sparser network with only the meaningful connections.Design/methodology/approach:In this paper,we propose two parameterless pruning algorithms from the global and local perspectives respectively,then the performance of them is examined using the ICIO table from different databases.Findings:The Searching Paths(SP)method extracts the strongest association paths from the global perspective,while Filtering Edges(FE)method captures the key links according to the local weight ratio.The results show that the FE method can basically include the SP method and become the best solution for the ICIO networks.Research limitations:There are still two limitations in this research.One is that the computational complexity may increase rapidly while processing the large-scale networks,so the proposed method should be further improved.The other is that much more empirical networks should be introduced to testify the scientificity and practicability of our methodology.Practical implications:The network pruning methods we proposed will promote the analysis of the ICIO network,in terms of community detection,link prediction,and spatial econometrics,etc.Also,they can be applied to many other complex networks with similar characteristics.Originality/value:This paper improves the existing research from two aspects,namely,considering the heterogeneity of weights and avoiding the interference of parameters.Therefore,it provides a new idea for the research of network backbone extraction.
基金supported partially by the science and technology project of CQ CSTC(No.cstc2012jjA40037)
文摘In wireless sensor network,virtual backbone is a cost effective broadcasting method.Connected dominating set formation is proposed to construct a virtual backbone.However,it is NP-Hard to find a minimum connected dominating set in an arbitrary graph.In this paper,based on cross-entropy method,we present a novel backbone formulation algorithm(BFA-CE)in wireless sensor network.In BFA-CE,a maximal independent set is got at first and nodes in the independent set are required to get their action sets.Based on those action sets,a backbone is generated with the cross-entropy method.Simulation results show that our algorithm can effectively reduce the size of backbone network within a reasonable message overhead,and it has lower average node degree.This approach can be potentially used in designing efficient broadcasting strategy or working as a backup routing of wireless sensor network.
文摘A new polysaccharide was extracted and purified from the roots of Angelica sinensis (Oliv) Diels (ASD). Its composition and linkage was elucidated by selective hydrolysis and GC/MS analysis of its derivatives. The polysaccharide was made of → 1) Fruf(2→and→6) Glcp (l→as its backbone with highly branched structure. To our best knowledge, this is the first report of the fructose residue in polysaccharides from the roots of the ASD.
文摘An automatic procedure for building a protein polyalanine backbone from guiding alpha-carbon positions is presented here,which is different from a previously developed'spare parts'approach(Jones and Thirup,1986;Claessens et al.,1989). In our procedure,the geometric restraint of angle N-CA-C is used to generate a list of polypeptide chains,and several filters are used later to select the best conformer.The most important filter is based upon the Ramachandran scatter plot of mainchain dihedral angles PHI and PSI.Results for all test cases are satisfactory,with more than 95%of peptide planes correctly reconstructed and the overall root-mean-square deviation less than 0.5 angstrom compared with the refined X-ray coordinates.
文摘Ths paper,based on the principles of geometric self-similarity of fractal theory and some research results of rotein chemistry,improved the method of comput-ing protein fractal dimensions,and computed fractal dimensions of some protein back bone,secondary and assumed folding structures.The relationship between protein back-bone strucrural fractal dimensions and its spatial structures was investigated.The results indicated that protein backbone fractal dimensions not only have a close relation with protein secondary structure,but also with its folding.In addition,the folding of protein Polypeptide chains in 3-D space may be similar to the other macromolecular chain be haviour described by the self-avoiding walks(SAW)model.
基金This work is supported by Fundamental Research Funds for the Central Universities of China(328201911)C.G.(Chao Guo),the Open Project Program of National Engineering Laboratory for Agri-product Quality Traceability,C.G.(Chao Guo)+2 种基金Beijing Technology and Business University(BTBU)No.AQT-2018Y-B4,C.G.(Chao Guo)Higher Education Department of the Ministry of Education Industry-university Cooperative Education Project,C.G.(Chao Guo)Education and Teaching Reform Project of Beijing Electronic and Technology Institute,C.G.(Chao Guo).
文摘Under the background of the rapid development of ground mobile communication,the advantages of high coverage,survivability,and flexibility of satellite communication provide air support to the construction of space information network.According to the requirements of the future space information communication,a software-defined Space-Air-Ground Integrated network architecture was proposed.It consisted of layered structure satellite backbone network,deep space communication network,the stratosphere communication network and the ground network.The Space-Air-Ground Integrated network was supported by the satellite backbone network.It provided data relay for the missions such as deep space exploration and controlled the deep-space spacecraft when needed.In addition,it safeguarded the anti-destructibility of stratospheric communication and assisted the stratosphere to supplement ground network communication.In this paper,algorithm requirements of the congestion control and routing of satellite backbone protocols for heterogeneous users’services were proposed.The algorithm requirements of distinguishing different service objects for the deep space communication and stratospheric communication network protocols were described.Considering the realistic demand for the dynamic coverage of the satellite backbone network and node cost,the multi-layer satellite backbone network architecture was constructed.On this basis,the proposed Software-defined Space-Air-Ground Integrated network architecture could be built as a large,scalable and efficient communication network that could be integrated into space,air,and ground.
文摘Reaction of dimers of (R) thionophosphine sulfide (R = P - C6H4OMe,SMe ) with Co, (CO), yields the novel hexacobalt cluster [Co'(μ3, -S)2, (CO) 14 (μ4 -μ4- and the trinuclear clusterPSCH,)J 2' In 1, tw0 Co3S(C0)7 units linked by a novel phosphido-thio1ato bifunc-tiona1 bridging p'-SPR ligand as backbone.
文摘The modern telecommunication system is characterized by the rapid improvement of information and communication technologies, such as the improvement in the data rate, power consumption and Quality of Service (QoS). Based on this development, the next generation network (NGN) is shaped. The NGN is represented by a packet transport network demarcated functions and services. To provide transport functions in NGN, using Multi-Protocol Label Switching (MPLS) technology, there are two main problems, which are multipath routing and traffic distribution, which are what this paper works with. Accordingly, this paper proposes a solution to these two problems using optimization procedures to find the shortest path Dijkstra and Bellman-Ford, which is characterized by a high-speed-oriented selection of a single shortest path between the source and the destination, based on several selected criteria related to the optimal use of the network resources. Solving the information flow distribution problems in large number of nodes network applying salesman procedure or having NP-completeness, causes significant time delay, which means that the proposed solution is not suitable for real time applications. Accordingly, for real time applications, there is a need to move to other methods based on the use of several independent shortest paths.
文摘The Metro Ethernet Forum(MEF) put forward the concept of Carrier Ethernet(CE) to improve Ethernet technology and make it a transmission convergence layer solution for Next Generation Network(NGN).Provider Backbone Transport(PBT) is the result of the enhancement and improvement of the early Ethernet technologies and it is the new version of CE implementation technology and standard which is promising.Through studying the PBT-related technologies,PBT network structure,PBT advantages as the transmission convergence layer solution and its trend of future development,it is concluded that PBT can be used as the preferred technology of the transmission convergence layer in the NGN,though there are some problems to be solved for PBT.
文摘To learn about the need of post-oriented education training of backbone civilian nurses,and to provide scientific evidence for the promotion of training. Methods The convenience sampling method was performed,and an anonymous survey on 324 nurses who participated in the "backbone civilian nurses training program"from September 2013 to October 2015 was carried out by using self-made questionnaire.Results(1)Among the 324 nurses,12. 04% of them volunteered to participate in the training and 87. 96%were sent by their departments.(2)More than 90% of training contents met their needs.(3)The training methods in demand included theoretical classroom teaching,clinical observation and probation,seminars,clinical management practice,clinical problem discussion and clinical nursing practice(4)The training period suggested by most nurses was about 2 to 4 weeks. Conclusion It is important to strengthen the significance of post-oriented education training and to improve the quality and capacity of civilian through scientific education design and practical training programs.
文摘Clustering or connected dominating set (CDS) both approaches can establish a virtual backbone (VB) in wireless sensor networks (WSNs) or wireless mesh networks (WMNs). Each cluster consisting of a cluster head (CH) and its neighboring nodes can form a dominating set. After some bridging nodes were selected, cluster heads (CHs) connected through these bridging nodes naturally formed a CDS. Although CDS provides obvious backbone architecture, however, the number of cluster heads and bridging nodes may be too large, this may cause the loss of advantages of virtual backbone. When we effectively reduce their numbers, more effectively WCDS (Weakly Connected Dominating Set) can be fining out. Some essential topics on constructing WCDS-based VB in WSN/WMN are discussed in this paper. From the point of view of three different protocol layers, including network (NWK) layer, MAC layer, and physical (PHY) layer, we explore their cross-layer research topics and design algorithms. For NWK layer, area-based WCDS algorithms and routing strategies including via VB and not via VB are discussed. For MAC layer, a WCDS-based energy-efficient MAC protocol is presented. For PHY layer, battery-aware alternative VB selections and sensor nodes with different transmission ranges are addressed.
文摘This paper presents a novel algorithm for the gateway placement problem in Backbone Wireless Mesh Networks (BWMNs). Different from existing algorithms, the new algorithm incrementally identifies gateways and assigns mesh routers to identified gateways. The new algorithm can guarantee to find a feasible gateway placement satisfying Quality-of-Service (QoS) constraints, including delay constraint, relay load constraint and gateway capacity constraint. Experimental results show that its performance is as good as that of the best of existing algorithms for the gateway placement problem. But, the new algorithm can be used for BWMNs that do not form one connected component, and it is easy to implement and use.
文摘The 3-D structure of the β-adrenergic receptor with a molecular weight of 55,000 daltons is available from crystallographic data. Within one of the seven transmembrane ion channel helices in the β2-receptor, one loop of a helix ACADL has previously been proposed as the site that explains β2 activity (fights acute bronchitis) whereas ASADL in the β1-receptor at the corresponding site explains β1-activity (cardiac stimulation). The α-agonist responsible for this selective reaction is only 0.5% of the receptor molecular weight, and only 1.5% of the weight of the trans-membrane portion of the receptor. The understanding of the mechanism by which a small molecule on binding to a site on one single loop of a helix produces a specific agonist activity on an entire transmembrane ion channel is uncertain. A model of an α-helix is presented in which of pitch occurs at angles both smaller and larger than 180° n. Consequently, atomic coordinates in a peptide backbone α-helix match the data points of individual atom (and atom types) in the backbone. More precisely, eleven atoms in peptide backbone routinely equal one loop of a helix, instead of eleven amino acid residues equaling three loops of a helix;therefore, an α-helix can begin (or end) at any specific atom in a peptide backbone, not just at any specific amino acid. Wavefront Topology System and Finite Element Methods calculate this specific helical shape based only upon circumference, pitch, and phase. Only external forces which specifically affect circumference, pitch and/or phase (e.g. from agonist binding) can/will alter the shape of an α-helix.
文摘1 Technical Features of ZTE’sDWDM SystemThe toll backbone wave division equipmentof ZXWM M900 backbone transmissionplatform is well designed forlarge-capacity optical transmission. It canfully satisfy the networking and managementrequirements of diversified users and be fit forvarious toll backbone networks. The systemsupports up to 40 working wavelengths and up to400 Gb/s transmission capacity, and thewavelength selection and interval are in strictcompliance with ITU-T Recommendations. It
基金supported by the National Natural Science Foundation of China (52203241,21905225,22005121)the Science and Technology Program of Shaanxi Province (2022JM-229,2023-JC-QN-0448)+1 种基金Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University (KJS2208)H.Y.W.acknowledges the financial support from the National Research Foundation of Korea (2019R1A6A1A11044070,2020M3H4A3081814).
文摘Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.