Nominal contact resistance, minimum erosion and material transfer are required with low cost materials working in a wide currents range for DC relays. Ag-Ni contact materials have low contact resistance, but the erosi...Nominal contact resistance, minimum erosion and material transfer are required with low cost materials working in a wide currents range for DC relays. Ag-Ni contact materials have low contact resistance, but the erosion and material transfer are large at high current level. Ag-SnO2 contact materials have good anti-welding properties and resistance to arc erosion, but they have large contact resistance during working and are easily block SnO2 from flocking together on the surface at low current level. In this paper, the failure mechanisms of Ag-Ce contact material were studied. The surface morphologies of the contacts after electrical endurance test for Ag-Ce contact material were compared with that of Ag-Ni and Ag-SnO2 contact materials. The effect of Ce on the surface morphologies of the contacts after electrical endurance test was analyzed.展开更多
The development of mobile internet and internet of things brings the vigorous developing data service, which increases need of bandwidth sharply. Operators strive to develop the data service oriented LTE(long term evo...The development of mobile internet and internet of things brings the vigorous developing data service, which increases need of bandwidth sharply. Operators strive to develop the data service oriented LTE(long term evolution)technology, especially TD-LTE (time division-LTE) technology adopting the spectral asymmetric. This paper analyzed details of TD-LTE system networking, and studied the feasibility of TD-LTE and TD-SCDMA(TD-synchronous code division multiple access) system with the same spectrum. At last, the paper provided suggestions on networking of TD-LTE system.展开更多
Objective:To explore the potential mplecular mechanism of Puji Xiaodu Drink(普济消毒饮,PJX-DD)in the treatment of corona virus disease 2019(COVID-19)based on network pharmacology and molecu-lar docking technology.Meth...Objective:To explore the potential mplecular mechanism of Puji Xiaodu Drink(普济消毒饮,PJX-DD)in the treatment of corona virus disease 2019(COVID-19)based on network pharmacology and molecu-lar docking technology.Methods:The main active compounds of PJXDD were searched by Traditional Chinese Medicine Systems Pharmacology(TCMSP)database and related literature records,and the potential target of PJXDD was found by Swiss Target Prediction;relevant targets of COVID-19 were obtained through Gene Cards database.The PPI network of"drug-compound-target"and target protein interaction was constructed by STRING database and Cytoscape 3.6.1 software.The key targels were analyzed by MCODE plug-in.Finally,the common targets were used for GO enrichment analysis and KEGG pathway analysis by Enrichr.Molecular docking was used to screen the main active components that interact with key targets.Results:202 effective chemical components of PJXDD were screened,and 71 targets were applied to COVID-19.The results of molec-ular docking suggested that naringin and luteolin may be important active compounds of PJXDD against COV-ID-19.They may play a role in the treatment of COVID-19 by parieipating in the signaling pathways of inter-leukin signaling,cytok ine signaling in immune system,and the intrinsic pathway of apoptosis.Conclusion:PJX-DD plays an important role in anti-COVID-19 through multi-component,multi-target and multi-channel action in inflammatory response and immune regulation.展开更多
In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel tim...In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel time division multiplexing technology （TDM） based on multi-channel shared synchronizer is proposed in this paper to solve the constrained hardware resource problem of multi-system satellite navigation receiver. Through the using of control state machine and data register structure, we realize the multiplexing of bit synchronizer of navigation receiver, which saves the hardware resource. After the experiment, it can be verified that the receiver based on the bit synchronization and multiplexing technology can correctly restore the navigation information.展开更多
A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in this paper.A special d...A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in this paper.A special diagnostic signal current is injected into the fault distribution system,and then it is detected at the outlet terminals to identify the fault line and at the sectionalizing or branching point along the fault line to locate the fault section.The method has been put into application in actual distribution network and field experience shows that it can identify the fault line and locate the fault section correctly and effectively.展开更多
In this study, information related to optical fiber fusion splicing skills is consolidated by extracting explicit knowledge of the proficiency levels of skilled technicians in two ways. The first is to visually captur...In this study, information related to optical fiber fusion splicing skills is consolidated by extracting explicit knowledge of the proficiency levels of skilled technicians in two ways. The first is to visually capture and quantify those skills by identifying differences in the skill levels of a nationally certified technician and a highly skilled expert technician using motion capture software, the other is to explore the relevance of the operation and thinking processes by interviewing the expert technician and then attempt to quantify empirical tacit knowledge by an analysis of mobile tracking views using motion capture software. The results show that a technician＇s ability to engage in ＂sensory thinking＂, such as the proper management of visual and tactile cues, is the most important component of his or her proficiency during optical fiber fusion splicing operations, and it was clear that operations were complemented when work path movements were reduced.展开更多
A wavelength division multiplexer based on curved polymer planar waveguide is proposed. According to the coupled modetheory and the waveguide structure, the performance of the curved waveguide coupler (CWC) is analyze...A wavelength division multiplexer based on curved polymer planar waveguide is proposed. According to the coupled modetheory and the waveguide structure, the performance of the curved waveguide coupler (CWC) is analyzed. The results showthat CWC can accommodate wider multiplexing bandwidth than parallel straight waveguide coupler (SWC) due to thecompensation effect of the effective coupling length. The two variables, curvature radius and minimum spacing, increasethe design flexibility of the waveguide device. A 4-channel wavelength division multiplexing (WDM) system based onCWC is designed. The deviation of the center wavelength, due to the errors of curvature radius and minimum spacingduring fabrication process, is investigated. The smaller the curvature radius and the minimum spacing are, the larger thecentral wavelength deviation caused by the error of the curvature radius and the minimum spacing is, which provides someuseful theoretical basis for the design and the fabrication of polymer waveguide devices.展开更多
Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining wit...Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining with adhesive bonding. Correspondingly, there has been a large effort in improving the adhesive bonding characteristics by changing the surface properties using different surface treatment techniques. One such method is the atmospheric arc discharge process which develops a specific surface roughness which can be leveraged to improve adhesive bonding. In this paper the effect of a textured surface by arc discharge on the failure mode and strength of adhesively bonded aluminum alloy sheets is investigated. A single-lap joint configuration is used for simulation and experimental analysis. A two-dimensional （2D） finite element method （FEM） involving the morphology of treated surfaces and using interfacial elements based on a cohesive zone model （CZM） are used to predict the joint strength which is an enabler for faster product development cycles. The influence of arc process parameters： the arc current and the torch scanning speed, on the surface morphology and joint strength are explored in this study. Specifically, the present study shows that the surface treatment of aluminum alloys by arc discharge can strongly enhance adhesive bond strength. Additionally, arc treatment not only increases the joint strength but also improves the quality of bond along the interface （transition toward cohesive failure mode）. The current FE simulation of adhesive joint using the elastic and elasto-plastic （non-linear） material properties for adherend and adhesive, respectively, and cohesive zone elements for interface shows an accurate prediction of the resulting joint strength. By inclusion of non-linear multi-scale geometry model via considering the surface topographical changes after surface treatment the FE joint strength prediction can be successfully implemented.展开更多
In the heterogeneous wireless networks of the next generation, a large number of different radio access technologies will be integrated into a common network. This paper considers optimizing the utilization of spectru...In the heterogeneous wireless networks of the next generation, a large number of different radio access technologies will be integrated into a common network. This paper considers optimizing the utilization of spectrum resource in heterogeneous environment consisting two different networks： wireless local area network （WLAN） and time division-synchronous code division multiple access （TD-SCDMA） network. An optimal joint spectrum borrowing scheme maximizing overall network revenue is proposed with quality of service （QoS） constraints over both the WLAN and the TD-SCDMA cellular networks. Simulation results illustrate that system revenue earned in the proposed joint spectrum borrowing scheme is significantly larger than the case when individual networks are optimized independently.展开更多
文摘Nominal contact resistance, minimum erosion and material transfer are required with low cost materials working in a wide currents range for DC relays. Ag-Ni contact materials have low contact resistance, but the erosion and material transfer are large at high current level. Ag-SnO2 contact materials have good anti-welding properties and resistance to arc erosion, but they have large contact resistance during working and are easily block SnO2 from flocking together on the surface at low current level. In this paper, the failure mechanisms of Ag-Ce contact material were studied. The surface morphologies of the contacts after electrical endurance test for Ag-Ce contact material were compared with that of Ag-Ni and Ag-SnO2 contact materials. The effect of Ce on the surface morphologies of the contacts after electrical endurance test was analyzed.
基金Important National Science & Technology Specific Projects"New Generation Broadband Wireless Mobile Communication"2010 project"TD-LTE Large-Scale Technical Trial "( No. 2010ZX03002-009)
文摘The development of mobile internet and internet of things brings the vigorous developing data service, which increases need of bandwidth sharply. Operators strive to develop the data service oriented LTE(long term evolution)technology, especially TD-LTE (time division-LTE) technology adopting the spectral asymmetric. This paper analyzed details of TD-LTE system networking, and studied the feasibility of TD-LTE and TD-SCDMA(TD-synchronous code division multiple access) system with the same spectrum. At last, the paper provided suggestions on networking of TD-LTE system.
基金We thank for the funding support from the Henan Emergency Tackling Project(201100312300)Zhengzhou Emergency Tackling Project(ZZKJ2020604)。
文摘Objective:To explore the potential mplecular mechanism of Puji Xiaodu Drink(普济消毒饮,PJX-DD)in the treatment of corona virus disease 2019(COVID-19)based on network pharmacology and molecu-lar docking technology.Methods:The main active compounds of PJXDD were searched by Traditional Chinese Medicine Systems Pharmacology(TCMSP)database and related literature records,and the potential target of PJXDD was found by Swiss Target Prediction;relevant targets of COVID-19 were obtained through Gene Cards database.The PPI network of"drug-compound-target"and target protein interaction was constructed by STRING database and Cytoscape 3.6.1 software.The key targels were analyzed by MCODE plug-in.Finally,the common targets were used for GO enrichment analysis and KEGG pathway analysis by Enrichr.Molecular docking was used to screen the main active components that interact with key targets.Results:202 effective chemical components of PJXDD were screened,and 71 targets were applied to COVID-19.The results of molec-ular docking suggested that naringin and luteolin may be important active compounds of PJXDD against COV-ID-19.They may play a role in the treatment of COVID-19 by parieipating in the signaling pathways of inter-leukin signaling,cytok ine signaling in immune system,and the intrinsic pathway of apoptosis.Conclusion:PJX-DD plays an important role in anti-COVID-19 through multi-component,multi-target and multi-channel action in inflammatory response and immune regulation.
基金the National Natural Science Foundation of China under Grant，the China Postdoctoral Science Foundation under Grant No.2013M530526，the Fundamental Research Funds for the Central Universities under Grant No.FRF-TP-14-046A2
文摘In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel time division multiplexing technology （TDM） based on multi-channel shared synchronizer is proposed in this paper to solve the constrained hardware resource problem of multi-system satellite navigation receiver. Through the using of control state machine and data register structure, we realize the multiplexing of bit synchronizer of navigation receiver, which saves the hardware resource. After the experiment, it can be verified that the receiver based on the bit synchronization and multiplexing technology can correctly restore the navigation information.
基金Postdoctoral Foundation of China(No.20070410755)PAN Zhencun,born in 1962,male,postdoctor researcher.
文摘A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in this paper.A special diagnostic signal current is injected into the fault distribution system,and then it is detected at the outlet terminals to identify the fault line and at the sectionalizing or branching point along the fault line to locate the fault section.The method has been put into application in actual distribution network and field experience shows that it can identify the fault line and locate the fault section correctly and effectively.
文摘In this study, information related to optical fiber fusion splicing skills is consolidated by extracting explicit knowledge of the proficiency levels of skilled technicians in two ways. The first is to visually capture and quantify those skills by identifying differences in the skill levels of a nationally certified technician and a highly skilled expert technician using motion capture software, the other is to explore the relevance of the operation and thinking processes by interviewing the expert technician and then attempt to quantify empirical tacit knowledge by an analysis of mobile tracking views using motion capture software. The results show that a technician＇s ability to engage in ＂sensory thinking＂, such as the proper management of visual and tactile cues, is the most important component of his or her proficiency during optical fiber fusion splicing operations, and it was clear that operations were complemented when work path movements were reduced.
基金This work was partially supported by the National Natural ScienceFoundation of China (No.60577014)the Young Teacher Cultiva-tion Foundation of Dalian University of Technology (No. 893210)the Doctor Start-up Foundation of Dalian University of Tech-nology (No. 893322).
文摘A wavelength division multiplexer based on curved polymer planar waveguide is proposed. According to the coupled modetheory and the waveguide structure, the performance of the curved waveguide coupler (CWC) is analyzed. The results showthat CWC can accommodate wider multiplexing bandwidth than parallel straight waveguide coupler (SWC) due to thecompensation effect of the effective coupling length. The two variables, curvature radius and minimum spacing, increasethe design flexibility of the waveguide device. A 4-channel wavelength division multiplexing (WDM) system based onCWC is designed. The deviation of the center wavelength, due to the errors of curvature radius and minimum spacingduring fabrication process, is investigated. The smaller the curvature radius and the minimum spacing are, the larger thecentral wavelength deviation caused by the error of the curvature radius and the minimum spacing is, which provides someuseful theoretical basis for the design and the fabrication of polymer waveguide devices.
文摘Aluminum alloys are being increasingly applied in the automotive industry as a means to reduce mass. Their application to the vehicle structure is typically via a combination of either mechanical or fusion joining with adhesive bonding. Correspondingly, there has been a large effort in improving the adhesive bonding characteristics by changing the surface properties using different surface treatment techniques. One such method is the atmospheric arc discharge process which develops a specific surface roughness which can be leveraged to improve adhesive bonding. In this paper the effect of a textured surface by arc discharge on the failure mode and strength of adhesively bonded aluminum alloy sheets is investigated. A single-lap joint configuration is used for simulation and experimental analysis. A two-dimensional （2D） finite element method （FEM） involving the morphology of treated surfaces and using interfacial elements based on a cohesive zone model （CZM） are used to predict the joint strength which is an enabler for faster product development cycles. The influence of arc process parameters： the arc current and the torch scanning speed, on the surface morphology and joint strength are explored in this study. Specifically, the present study shows that the surface treatment of aluminum alloys by arc discharge can strongly enhance adhesive bond strength. Additionally, arc treatment not only increases the joint strength but also improves the quality of bond along the interface （transition toward cohesive failure mode）. The current FE simulation of adhesive joint using the elastic and elasto-plastic （non-linear） material properties for adherend and adhesive, respectively, and cohesive zone elements for interface shows an accurate prediction of the resulting joint strength. By inclusion of non-linear multi-scale geometry model via considering the surface topographical changes after surface treatment the FE joint strength prediction can be successfully implemented.
基金Supported by the National Natural Science Foundation of China （60832009）, the Natural Sciences Foundation of Beijing （4102044）, the Fundamental Research Funds for the Central Universities （BUPT2009RC019）, and the National Major Prefects for Science and Technology Development （2009ZX03003-003-01）.
文摘In the heterogeneous wireless networks of the next generation, a large number of different radio access technologies will be integrated into a common network. This paper considers optimizing the utilization of spectrum resource in heterogeneous environment consisting two different networks： wireless local area network （WLAN） and time division-synchronous code division multiple access （TD-SCDMA） network. An optimal joint spectrum borrowing scheme maximizing overall network revenue is proposed with quality of service （QoS） constraints over both the WLAN and the TD-SCDMA cellular networks. Simulation results illustrate that system revenue earned in the proposed joint spectrum borrowing scheme is significantly larger than the case when individual networks are optimized independently.
