This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（...This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（FFT） correlation through hyper code technique and the amount of points in every FFT correlation by using an averaging correlation method. To validate the proposed acquisition performance, the paper applies this algorithm to the real L2C signal collected by the global positioning system（GPS） L2C intermediate frequency（IF） signal sampler—SIS100L2C. The acquisition results show that the proposed modified algorithm can acquire the code phase accurately with less calculation and its acquisition performance is better than the single hyper code method.展开更多
Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser&...Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser's curiosity increases to know about the production process which can be accomplished by production traceability system.The traceability system can store and superintend the specific attribute information about products regarding the productive centre,producer and production finish data.The products undergo various circulation processes and they are being managed by individually constructed traceability system.Thus,it is difficult for the producer and the consumer to guarantee the safety from transpirable issues about the falsification of production traceability because the traceability information can be re-produced by forging through various ways.So in this paper,we proposed a system for integrated management of agro-fishery products based on quick response code(QR-code)for forgery prevention which may help to solve these issues.The proposed system makes QR-code using production information provided by producer.And then it is provided to the distributor and the consumer through integrated service model using the QR-code.Therefore,this system make sure to provide the same production traceability about the products to the distributor and the consumer and always keeps both updated with the same information.展开更多
X-Code is one of the most important redundant array of independent disk （RAID）-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and...X-Code is one of the most important redundant array of independent disk （RAID）-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is proposed to extend X-Code to an arbitrary length. It can be further proved that the code shortening algorithm maintains the maximum-distance-separable （MDS） property of X-Code, and namely, the shortened X-Code is still MDS code with the optimal space efficiency. In the context of the shortening algorithm for X-Code, an in-depth performance analysis on X-Code at consecutive code lengths is conducted, and the impacts of the code shortening algorithm on the performance of X-Code in various performance metrics are revealed.展开更多
A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional densit...A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.展开更多
GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of ...GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of the whole quality of toys and the development of toysindustry. It also improves the competitive ability of our toys in international market. It is a newlandmark of the development of toys industry in China.展开更多
The KHNP （Korea Hydro ＆ Nuclear Power Co.） has developed a multipurpose nuclear safety analysis code called SPACE （the safety and performance analysis code） for nuclear power plants. SPACE code is a best-estimate...The KHNP （Korea Hydro ＆ Nuclear Power Co.） has developed a multipurpose nuclear safety analysis code called SPACE （the safety and performance analysis code） for nuclear power plants. SPACE code is a best-estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. In this paper, LOFT （loss of fluid test） L9-3 experiment using the SPACE code was selected to confirm the capability of SPACE code and the results calculated by the SPACE code are compared with those measured through the experiment. The results were compared with the experimental data and those of the other code simulations. Throughout the simulation result, it was concluded that the SPACE code can effectively simulate LOFT L9-3 experiment.展开更多
利用光场的高斯-赫米特源项展开法,推导了粒子运动一维方程加三维修正和光场幅度、光束半径、瑞利参数的非线性方程组,编制稳态Matlab FEL code程序,初始粒子加载与国际通用软件Genesis进行对比,吻合很好。新程序对于X射线FEL理论研究...利用光场的高斯-赫米特源项展开法,推导了粒子运动一维方程加三维修正和光场幅度、光束半径、瑞利参数的非线性方程组,编制稳态Matlab FEL code程序,初始粒子加载与国际通用软件Genesis进行对比,吻合很好。新程序对于X射线FEL理论研究的深化,实验装置的设计和改进具有重要意义。展开更多
Based on the discussion of relationships between thinning and wind damage, and published information, a method for estimating risk ratios of wind damage was developed. Estimations of risk-ratio for Pinus thunbergii tr...Based on the discussion of relationships between thinning and wind damage, and published information, a method for estimating risk ratios of wind damage was developed. Estimations of risk-ratio for Pinus thunbergii trees and stands were de-duced from stem bending theory and coefficients characterizing wind profile, distribution of branches and optical stratification po-rosity. The results showed that if the value of constant b in the branch distribution-model equals the attenuation coefficient s in the wind profile model for a single tree crown, then the parameter H/D1.33 (height over stem diameter cubed) can be used to compare and evaluate the risk-ratio of wind damage for individual trees. The same method can be applied to stands using the coefficient of wind profile in a stand, i.e. attenuation coefficient , the coefficient from distributions of optical stratification porosity, i.e. extinction coefficient , and the parameter D1.33. The application of parameter H/D1.33 and the process of determining risk ra-tios of wind damage for stands were also given in the paper.展开更多
Chronic alcohol consumption induces hepatic steatosis, the early stage of alcoholic liver disease （ALD）. The aim ofpresent study is to investigate the protective effect ofPanax notoginseng saponins （PNS） against c...Chronic alcohol consumption induces hepatic steatosis, the early stage of alcoholic liver disease （ALD）. The aim ofpresent study is to investigate the protective effect ofPanax notoginseng saponins （PNS） against chronic ethanol-induced hepaticsteatosis in vivo. Mice were pair-fed a modified Lieber-DeCarli liquid diet containing alcohol or isocaloric maltose dextrin ascontrol diet with or without PNS （200 mg/kg, BW） for 8 weeks. Animals supplemented with PNS were protected against hepaticlipid accumulation induced by chronic ethanol exposure. Accordingly, PNS could significantly decrease the elevation of plasmatriglyceride, plasma enzyme activities, i.e. alanine aminotransferase （ALT） and aspartate aminotransferase （AST）, and hepaticTNF-ct and IL-6 levels which were induced by chronic alcohol exposure. In addition, PNS markedly reduced the lipolysis ofwhite adipose tissue （WAT） that stimulated by alcohol feeding through the inhibiting protein expression of phosphorylation ofhormone-sensitive lipase （p-HSL）, rather than total HSL. Furthermore, alcohol exposure also enhanced fatty acid uptake capacityin liver by elevated hepatic CD36 expression, which could attenuated by PNS treatment. These results demonstrate that PNSsupplementation protects against chronic ethanol-induced hepatic steatosis, which is associated with ameliorating dysfunctionallipid metabolism of WAT and the reduced inflammatory cytokines. Our findings suggested that PNS might be potential to bedeveloped as an effective agent for the treatment of chronic alcoholic steatosis.展开更多
以某台2.25Cr-1Mo-V钢加氢反应器为例,从工程角度介绍现行设计方法与ASME Code Case 2605-3在反应器设计中的应用,说明过去留有一定余量的设计是设备安全运行的原因之一。探讨了压力和温度载荷对蠕变参数的影响,其中压力对三轴度系数影...以某台2.25Cr-1Mo-V钢加氢反应器为例,从工程角度介绍现行设计方法与ASME Code Case 2605-3在反应器设计中的应用,说明过去留有一定余量的设计是设备安全运行的原因之一。探讨了压力和温度载荷对蠕变参数的影响,其中压力对三轴度系数影响较大,而温度对蠕变松弛影响显著。最后提出在业主非强制要求进行完整分析的前提下,ASME Code Case 2605-3在工程上的简化应用。展开更多
Inspired by the idea that bionic non-smooth surfaces(BNSS)can reduce water flow resistance,the application of BNSS resistance reduction method in grooves surface of antiskid tire tread pattern has been investigated fo...Inspired by the idea that bionic non-smooth surfaces(BNSS)can reduce water flow resistance,the application of BNSS resistance reduction method in grooves surface of antiskid tire tread pattern has been investigated for increasing hydroplaning velocity of tire by using computational fluid dynamics(CFD)simulation.Three kinds of BNSS(riblet,convex dome,and dimple concave)are arranged in tire tread grooves to study the water flow resistance effects in grooves with non-smooth characteristics.A tire-water coupled model is established and CFD technique is applied to simulating hydroplaning.The simulation results show that BNSS grooves can reduce water flow resistance and increase mean flow rate by disturbing the eddy movement in boundary layers.The drag forces of riblet and dimple surface are lower and drainage capacity is higher than those of smooth surface under the same void space on tread pattern,but it is not in dome.BNSS is a good way to promote antiskid performance without increasing additional groove space;extra tire-road noise production is therefore avoided due to groove space enlargement.展开更多
To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method （i.e.the pyrolysis process of the sludge with ZnCl2 activation）,the characteris...To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method （i.e.the pyrolysis process of the sludge with ZnCl2 activation）,the characteristic of mass loss and gas products generated during pyrolysis of the sludge with ZnCl2 activation were analyzed by thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy （TG-FTIR）.The kinetic parameters were calculated by the Coats-Redfem method and the mechanism models were established.The role of ZnCl2 in the pyrolysis process of the sludge with ZnCl2 activation was also illustrated through the comparison of the pyrolysis characteristics and kinetics of the sludge with and without ZnCl2 activation.The results showed that the pyrolysis process of the sludge with ZnCl2 activation can be divided into four stages including the dehydration of sludge and initial depolymerization of a small portion of organics matters,the decomposition of large molecular organic matters into small molecular intermediates,the further degradation of intermediates and volatilization of ZnCl2,and the decomposition of inorganic minerals and undecomposed organic matters.CO2,CO,CH4,H2O,some aldehydes and carboxylic acids are the major pyrolysis gaseous products.The activation energies and pre-exponential factors are in the range of 28.84-206.42 kJ/mol and 9885.16-8.08× 1011 min-1,respectively.During the pyrolysis of sludge,ZnC12 not only can function as a dehydration agent and inhibit the formation of tar,but also can peptize the organic matters in the sludge,making them easier to be decomposed.展开更多
Jet pipe electro-hydraulic servo valve is the heart of feedback control systems,and it is one of the mechatronic components used for precision flow control application.It consists of several precision and ddicate comp...Jet pipe electro-hydraulic servo valve is the heart of feedback control systems,and it is one of the mechatronic components used for precision flow control application.It consists of several precision and ddicate components.The performance of the jet pipe servo valve depends on many parameters.During the developmental stage,it is very difficult to ascertain the function parameters.The steady-state analysis of jet pipe electro-hydraulic servo valve has been made to simulate its fluid characteristics （flowin,flow-out,leakage flow,recovery or load pressure,etc.） by mathematical modeling.Theoretical model was conducted on various affecting parameters on the pressure,the main flow rate of fluid,or leakage flow through the receiver holes.The major parameters studied are jet pipe nozzle diameters,receiver hole diameters,angle between the two centre-lines of receiver hole,nozzle offset,and nozzle stand-of distance.In this paper the research is important to determine and optimize the structural parameters of jet pipe servo valve.Thus,equations of the pressure and flow characteristics are set up and the optimal structural parameters of jet pipe are established.展开更多
Aiming at large error when inertial devices measure the roll angle under high overload conditions,the article designs one kind of roll angle measurement system based on magneto-resistive sensor which calculates the ro...Aiming at large error when inertial devices measure the roll angle under high overload conditions,the article designs one kind of roll angle measurement system based on magneto-resistive sensor which calculates the roll angle by micro controller STM32.Experiment results of a triaxial turntable show that using magneto-resistive sensor to measure roll angle is feasible and of high accuracy,and it can calculate the roll angle of the conventional projectile with the error in 1°.展开更多
This paper presents a multi-interface embedded server architecture for remote real-time monitoring system and distributed monitoring applications. In the scheme,an embedded microprocessor( LPC3250 from NXP) is chosen ...This paper presents a multi-interface embedded server architecture for remote real-time monitoring system and distributed monitoring applications. In the scheme,an embedded microprocessor( LPC3250 from NXP) is chosen as the CPU of the embedded server with a linux operation system( OS) environment. The embedded server provides multiple interfaces for supporting various application scenarios. The whole network is based on local area network and adopts the Browser / Server( B / S) model. The monitoring and control node is as a browser endpoint and the remote node with an embedded server is as a server endpoint. Users can easily acquire various sensors information through writing Internet protocol address of remote node on the computer browser. Compared with client / server( C / S) mode,B / S model needs less maintain and can be applicable to large user group. In addition,a simple network management protocol( SNMP) is used for management of devices in Internet protocol( IP) networks. The results of the demonstration experiment show that the proposed system gives good support to manage the network from different user terminals and allows the users to better interact with the ambient environment.展开更多
基金supported by the Fundamental Research Fund for the Central Universities(NS2013016)
文摘This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（FFT） correlation through hyper code technique and the amount of points in every FFT correlation by using an averaging correlation method. To validate the proposed acquisition performance, the paper applies this algorithm to the real L2C signal collected by the global positioning system（GPS） L2C intermediate frequency（IF） signal sampler—SIS100L2C. The acquisition results show that the proposed modified algorithm can acquire the code phase accurately with less calculation and its acquisition performance is better than the single hyper code method.
基金The MSIP(Ministry of Science,ICT&Future Planning),Korea,under the ITRC(Information Technology Research Center)support program(NIPA-2013-H0301-13-2006)supervised by the NIPA(National IT Industry Promotion Agency)
文摘Recently,both the importance and awareness relating to food safety relating to agrochemicals,chemical fertilizers,the pollution of ecosystem and unwholesome foods are growing rapidly.For the same reason,the purchaser's curiosity increases to know about the production process which can be accomplished by production traceability system.The traceability system can store and superintend the specific attribute information about products regarding the productive centre,producer and production finish data.The products undergo various circulation processes and they are being managed by individually constructed traceability system.Thus,it is difficult for the producer and the consumer to guarantee the safety from transpirable issues about the falsification of production traceability because the traceability information can be re-produced by forging through various ways.So in this paper,we proposed a system for integrated management of agro-fishery products based on quick response code(QR-code)for forgery prevention which may help to solve these issues.The proposed system makes QR-code using production information provided by producer.And then it is provided to the distributor and the consumer through integrated service model using the QR-code.Therefore,this system make sure to provide the same production traceability about the products to the distributor and the consumer and always keeps both updated with the same information.
基金supported by the National Basic Research Program of China (Grant Nos.2011CB302300, 2011CB302301)the National High-Technology Research and Development Program of China (Grant Nos.2009AA01A401,2009AA01A402)+1 种基金the National Natural Science Foundation of China (Grant Nos.60873028, 60933002, 61025008)the Changjiang Innovation Group of Education of China (Grant No.IRT0725)
文摘X-Code is one of the most important redundant array of independent disk （RAID）-6 codes which are capable of tolerating double disk failures. However, the code length of X-Code is restricted to be a prime number, and such code length restriction of X-Code limits its usage in the real storage systems. Moreover, as a vertical RAID-6 code, X-Code can not be extended easily to an arbitrary code length like horizontal RAID-6 codes. In this paper, a novel and efficient code shortening algorithm for X-Code is proposed to extend X-Code to an arbitrary length. It can be further proved that the code shortening algorithm maintains the maximum-distance-separable （MDS） property of X-Code, and namely, the shortened X-Code is still MDS code with the optimal space efficiency. In the context of the shortening algorithm for X-Code, an in-depth performance analysis on X-Code at consecutive code lengths is conducted, and the impacts of the code shortening algorithm on the performance of X-Code in various performance metrics are revealed.
基金Leading Academic Discipline Project of Shanghai Municipal Education Commission,China(No.J51801)Shanghai Second Polytechnic University Foundation,China(No.QD209008)Leading Academic Discipline Project of Shanghai Second Polytechnic University,China(No.XXKZD1302)
文摘A low-complexity algorithm is proposed in this paper in order to optimize irregular low-density parity-check （LDPC） codes.The algorithm proposed can calculate the noise threshold by means of a one-dimensional density evolution and search the optimal degree profiles with fast-convergence differential evolution,so that it has a lower complexity and a faster convergence speed.Simulation resuits show that the irregular LDPC codes optimized by the presented algorithm can also perform better than Turbo codes at moderate block length even with less computation cost.
文摘GB 6675-2003 National Safety Technical Code for Toys, in which the safetylevel of toys has achieved the advanced international level, is the general standard of all kinds oftoys. It will facilitate the improvement of the whole quality of toys and the development of toysindustry. It also improves the competitive ability of our toys in international market. It is a newlandmark of the development of toys industry in China.
文摘The KHNP （Korea Hydro ＆ Nuclear Power Co.） has developed a multipurpose nuclear safety analysis code called SPACE （the safety and performance analysis code） for nuclear power plants. SPACE code is a best-estimated two-phase three-field thermal-hydraulic analysis code used to analyze the safety and performance of pressurized water reactors. In this paper, LOFT （loss of fluid test） L9-3 experiment using the SPACE code was selected to confirm the capability of SPACE code and the results calculated by the SPACE code are compared with those measured through the experiment. The results were compared with the experimental data and those of the other code simulations. Throughout the simulation result, it was concluded that the SPACE code can effectively simulate LOFT L9-3 experiment.
基金This study was supported by Innovation Research Project of Chinese Academy of Sciences and the Ministry of Culture and Education Japanese Government.
文摘Based on the discussion of relationships between thinning and wind damage, and published information, a method for estimating risk ratios of wind damage was developed. Estimations of risk-ratio for Pinus thunbergii trees and stands were de-duced from stem bending theory and coefficients characterizing wind profile, distribution of branches and optical stratification po-rosity. The results showed that if the value of constant b in the branch distribution-model equals the attenuation coefficient s in the wind profile model for a single tree crown, then the parameter H/D1.33 (height over stem diameter cubed) can be used to compare and evaluate the risk-ratio of wind damage for individual trees. The same method can be applied to stands using the coefficient of wind profile in a stand, i.e. attenuation coefficient , the coefficient from distributions of optical stratification porosity, i.e. extinction coefficient , and the parameter D1.33. The application of parameter H/D1.33 and the process of determining risk ra-tios of wind damage for stands were also given in the paper.
基金Research Committee of the University of Macao(Grant No.MYRG123-ICMS12 and MYRG111-ICMS13)from Macao Science and Technology Development Fund(Grant No.010/2013/A1)
文摘Chronic alcohol consumption induces hepatic steatosis, the early stage of alcoholic liver disease （ALD）. The aim ofpresent study is to investigate the protective effect ofPanax notoginseng saponins （PNS） against chronic ethanol-induced hepaticsteatosis in vivo. Mice were pair-fed a modified Lieber-DeCarli liquid diet containing alcohol or isocaloric maltose dextrin ascontrol diet with or without PNS （200 mg/kg, BW） for 8 weeks. Animals supplemented with PNS were protected against hepaticlipid accumulation induced by chronic ethanol exposure. Accordingly, PNS could significantly decrease the elevation of plasmatriglyceride, plasma enzyme activities, i.e. alanine aminotransferase （ALT） and aspartate aminotransferase （AST）, and hepaticTNF-ct and IL-6 levels which were induced by chronic alcohol exposure. In addition, PNS markedly reduced the lipolysis ofwhite adipose tissue （WAT） that stimulated by alcohol feeding through the inhibiting protein expression of phosphorylation ofhormone-sensitive lipase （p-HSL）, rather than total HSL. Furthermore, alcohol exposure also enhanced fatty acid uptake capacityin liver by elevated hepatic CD36 expression, which could attenuated by PNS treatment. These results demonstrate that PNSsupplementation protects against chronic ethanol-induced hepatic steatosis, which is associated with ameliorating dysfunctionallipid metabolism of WAT and the reduced inflammatory cytokines. Our findings suggested that PNS might be potential to bedeveloped as an effective agent for the treatment of chronic alcoholic steatosis.
文摘以某台2.25Cr-1Mo-V钢加氢反应器为例,从工程角度介绍现行设计方法与ASME Code Case 2605-3在反应器设计中的应用,说明过去留有一定余量的设计是设备安全运行的原因之一。探讨了压力和温度载荷对蠕变参数的影响,其中压力对三轴度系数影响较大,而温度对蠕变松弛影响显著。最后提出在业主非强制要求进行完整分析的前提下,ASME Code Case 2605-3在工程上的简化应用。
基金Colleges and Universities in Jiangsu Province Pans to Graduate Research and Innovation,China(No.CXLX13_676)Jiangsu Province Six Talents Peak Project,China(No.2011A031)
文摘Inspired by the idea that bionic non-smooth surfaces(BNSS)can reduce water flow resistance,the application of BNSS resistance reduction method in grooves surface of antiskid tire tread pattern has been investigated for increasing hydroplaning velocity of tire by using computational fluid dynamics(CFD)simulation.Three kinds of BNSS(riblet,convex dome,and dimple concave)are arranged in tire tread grooves to study the water flow resistance effects in grooves with non-smooth characteristics.A tire-water coupled model is established and CFD technique is applied to simulating hydroplaning.The simulation results show that BNSS grooves can reduce water flow resistance and increase mean flow rate by disturbing the eddy movement in boundary layers.The drag forces of riblet and dimple surface are lower and drainage capacity is higher than those of smooth surface under the same void space on tread pattern,but it is not in dome.BNSS is a good way to promote antiskid performance without increasing additional groove space;extra tire-road noise production is therefore avoided due to groove space enlargement.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51008106)
文摘To obtain the pyrolysis characteristics and kinetics of preparation process of sludge-based activated carbon by ZnCl2 activation method （i.e.the pyrolysis process of the sludge with ZnCl2 activation）,the characteristic of mass loss and gas products generated during pyrolysis of the sludge with ZnCl2 activation were analyzed by thermogravimetric analysis coupled with Fourier Transform Infrared Spectroscopy （TG-FTIR）.The kinetic parameters were calculated by the Coats-Redfem method and the mechanism models were established.The role of ZnCl2 in the pyrolysis process of the sludge with ZnCl2 activation was also illustrated through the comparison of the pyrolysis characteristics and kinetics of the sludge with and without ZnCl2 activation.The results showed that the pyrolysis process of the sludge with ZnCl2 activation can be divided into four stages including the dehydration of sludge and initial depolymerization of a small portion of organics matters,the decomposition of large molecular organic matters into small molecular intermediates,the further degradation of intermediates and volatilization of ZnCl2,and the decomposition of inorganic minerals and undecomposed organic matters.CO2,CO,CH4,H2O,some aldehydes and carboxylic acids are the major pyrolysis gaseous products.The activation energies and pre-exponential factors are in the range of 28.84-206.42 kJ/mol and 9885.16-8.08× 1011 min-1,respectively.During the pyrolysis of sludge,ZnC12 not only can function as a dehydration agent and inhibit the formation of tar,but also can peptize the organic matters in the sludge,making them easier to be decomposed.
基金National Science and Technology Supporting Program,China(No.2011BAJ02B06)Aeronautical Science Foundation of China(No.20090738003)National Natural Science Foundations of China(No.51175378,No.50775161)
文摘Jet pipe electro-hydraulic servo valve is the heart of feedback control systems,and it is one of the mechatronic components used for precision flow control application.It consists of several precision and ddicate components.The performance of the jet pipe servo valve depends on many parameters.During the developmental stage,it is very difficult to ascertain the function parameters.The steady-state analysis of jet pipe electro-hydraulic servo valve has been made to simulate its fluid characteristics （flowin,flow-out,leakage flow,recovery or load pressure,etc.） by mathematical modeling.Theoretical model was conducted on various affecting parameters on the pressure,the main flow rate of fluid,or leakage flow through the receiver holes.The major parameters studied are jet pipe nozzle diameters,receiver hole diameters,angle between the two centre-lines of receiver hole,nozzle offset,and nozzle stand-of distance.In this paper the research is important to determine and optimize the structural parameters of jet pipe servo valve.Thus,equations of the pressure and flow characteristics are set up and the optimal structural parameters of jet pipe are established.
基金National Natural Science Foundation of China(No.61004127)
文摘Aiming at large error when inertial devices measure the roll angle under high overload conditions,the article designs one kind of roll angle measurement system based on magneto-resistive sensor which calculates the roll angle by micro controller STM32.Experiment results of a triaxial turntable show that using magneto-resistive sensor to measure roll angle is feasible and of high accuracy,and it can calculate the roll angle of the conventional projectile with the error in 1°.
基金Sponsored by the National High Technology Research and Development Program(Grant No.2012AA02A604)
文摘This paper presents a multi-interface embedded server architecture for remote real-time monitoring system and distributed monitoring applications. In the scheme,an embedded microprocessor( LPC3250 from NXP) is chosen as the CPU of the embedded server with a linux operation system( OS) environment. The embedded server provides multiple interfaces for supporting various application scenarios. The whole network is based on local area network and adopts the Browser / Server( B / S) model. The monitoring and control node is as a browser endpoint and the remote node with an embedded server is as a server endpoint. Users can easily acquire various sensors information through writing Internet protocol address of remote node on the computer browser. Compared with client / server( C / S) mode,B / S model needs less maintain and can be applicable to large user group. In addition,a simple network management protocol( SNMP) is used for management of devices in Internet protocol( IP) networks. The results of the demonstration experiment show that the proposed system gives good support to manage the network from different user terminals and allows the users to better interact with the ambient environment.
