Exploitation of sustainable energy sources requires the use of unique conversion and storage systems,such as solar panels,batteries,fuel cells,and electronic equipment.Thermal load management of these energy conversio...Exploitation of sustainable energy sources requires the use of unique conversion and storage systems,such as solar panels,batteries,fuel cells,and electronic equipment.Thermal load management of these energy conversion and storage systems is one of their challenges and concerns.In this article,the thermal management of these systems using thermoelectric modules is reviewed.The results show that by choosing the right option to remove heat from the hot side of the thermoelectric modules,it will be a suitable local cooling,and the thermoelectric modules increase the power and lifespan of the system by reducing the spot temperature.Thermoelectric modules were effective in reducing panel temperature.They increase the time to reach a temperature above 50℃ in batteries by 3 to 4 times.Also,in their integration with fuel cells,they increase the power density of the fuel cell.展开更多
Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity ...Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.展开更多
As the“engine”of equipment continuous operation and repeated operation, equipment maintenance support plays a more prominent role in the confrontation of symmetrical combat systems. As the basis and guide for the pl...As the“engine”of equipment continuous operation and repeated operation, equipment maintenance support plays a more prominent role in the confrontation of symmetrical combat systems. As the basis and guide for the planning and implementation of equipment maintenance tasks, the equipment damage measurement is an important guarantee for the effective implementation of maintenance support. Firstly,this article comprehensively analyses the influence factors to damage measurement from the enemy’s attributes, our attributes and the battlefield environment starting from the basic problem of wartime equipment damage measurement. Secondly, this article determines the key factors based on fuzzy comprehensive evaluation(FCE) and performed principal component analysis (PCA) on the key factors. Finally, the principal components representing more than 85%of the data features are taken as the input and the equipment damage quantity is taken as the output. The data are trained and tested by artificial neural network (ANN) and random forest (RF). In a word, FCE-PCA-RF can be used as a reference for the research of equipment damage estimation in wartime.展开更多
We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were use...We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response.展开更多
In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the test...In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.展开更多
Nowadays, rapid technological progress influences the dependability of equipments and also causes rapid obsolescence. The mechatronic and electronic equipment components are mostly affected by obsolescence. A new chal...Nowadays, rapid technological progress influences the dependability of equipments and also causes rapid obsolescence. The mechatronic and electronic equipment components are mostly affected by obsolescence. A new challenger unit possesses identical functionalities, but with higher performances. This work aims to find the optimal number of components which should be replaced by new-type units, under budgetary constraints. In this work, the new challenger unit is characterized by lower energy consumption and the optimization steps are based on genetic algorithm (GA). The result shows the importance of this type of replacement in order to economize energy consumption and to deal with obsolescence.展开更多
The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (...The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (UER) and multivariate linear regression (MLR) were used in this study. Loading equipment parameters such as bucket capacity, machine weight, engine power, boom length, digging depth, and dumping height were considered as variables. The results obtained by models and mean absolute error rate indicate that these models can be applied as the useful tool in determination of overhaul and maintenance cost of loading equipment. The results of this study can be used by the decision-makers for the specific surface mining operations.展开更多
Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medi...Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medium enterprises(SMEs)that are engaged in ISO 14001:2015 initiatives and consume electrical and electronic equipment(EEE)to enhance their performance and profitability.The methodology employed an exploratory approach involving the application of general equilibrium theory(GET)to contextualize the study and generate relevant parameters for deploying the random forest regression learning algorithm for predictions.Machine learning was applied to 80%of the samples for training,while simulation was conducted on the remaining 20%of samples based on quantities of EEE utilized over a specific period,utilization rates,repair rates,and average lifespans.The results demonstrate that the model’s predicted values are significantly close to the actual quantities of generated WEEE,and the model’s performance was evaluated using the mean squared error(MSE)and yielding satisfactory results.Based on this model,both companies and stakeholders can set realistic objectives for managing companies’WEEE,fostering sustainable socio-environmental practices.展开更多
Considering two characteristics of compact heat dissipation room and high heat flux, a novel miniature capillary pumped loop (MCPL) for electronics cooling was proposed. MCPL consists of evaporator, condenser, vapor a...Considering two characteristics of compact heat dissipation room and high heat flux, a novel miniature capillary pumped loop (MCPL) for electronics cooling was proposed. MCPL consists of evaporator, condenser, vapor and liquid line dissipates heat by boiling and condensation of working fluids with no extra power consumption. Working fluid circulation is ensured by vapor pressure and capillary head. Saturated wick screens vapor and liquid, and ensures one-way flow of working fluid with no extra valve. In order to promote heat dissipation capacity of MCPL, the intensified boiling and condensation structures are embedded into evaporator and condenser respectively, which are useful to increasing boiling and condensation efficiency. Startup and run characteristics are tested by experiments in the condition of different power inputs and working fluids. MCPL is capable of dissipating 80 W of thermal energy and keeping the bottom substrate temperature of evaporator at 80 ℃.展开更多
In view of the current reliability evaluation requirements of warship equipment based on component, this paper comprehensively considered the characteristics of components,and the component identification method, stru...In view of the current reliability evaluation requirements of warship equipment based on component, this paper comprehensively considered the characteristics of components,and the component identification method, structural decomposition method,component architecture modeling method were studied for warship equipment software. Based on the characteristics of warship equipment component, this paper proposed a formal modeling language based on Petri nets to realize the modeling of component software architecture and laid a foundation for the reliability evaluation method research of warship equipment component.展开更多
The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is m...The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5~3 times as large as that of smooth chip at the same subcooling.展开更多
High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the...High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.展开更多
The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain...The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.展开更多
Rare earth elements (REEs), especially heavy rare earth elements (HREEs), are in demand for their current and emerging applications in advanced technologies. Here we perform computer-driven micro-mapping at the millim...Rare earth elements (REEs), especially heavy rare earth elements (HREEs), are in demand for their current and emerging applications in advanced technologies. Here we perform computer-driven micro-mapping at the millimeter scale of the minerals that comprise Round Top Mountain, in west Texas, USA. This large rhyolite deposit is enriched in HREEs and such other critical elements as Li, Be, and U. Electron probe microanalysis of 2 × 2 mm areas of thin sections of the rhyolite produced individual maps of 16 elements. These were superimposed to generate a 16-element composition at each pixel. Principal components analysis of elements at each pixel identified the specific mineral at that site. The pixels were then relabeled as the appropriate minerals, thereby producing a single mineral map. The overall mineral composition of the 7 studied samples compared favorably with prior analyses of the Round Top deposit available in the literature. Likewise the range of porosity in the maps was consistent with that of previous direct measurements by water saturation. This new statistical and GIS-based technique provides a robust and unbiased approach to electron microprobe mapping. The study further showed that the high-value yttrofluorite grains exhibited little tendency to cluster with other late-stage trace minerals and that the samples extended the previously documented overall homogeneity of the deposit at field scale to this microscopic scale.展开更多
In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered main...In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered maintenance ( RCM) combined with condition-basedmaintenance ( CBM) and maintenance efficiency review (MER). A maintenance management informationsystem was constructed for electronic equipment for the purpose of failure analysis, reliabilityevaluation, and maintenance decisions such as time, mode, and plan. The best maintenance time couldbe predicted with failure analysis and reliability evaluation, which was mainly influenced byenvironmental stress. Suitable maintenance modes should be determined from equipment importance,failure aftereffect, maintenance condition, and economical power so as to ensure equipmentreliability and decrease the requirement of the maintenance source.展开更多
It is difficult to develop the corresponding fault diagnosis system and the software reusability is bad because the engineering equipment types are so many and their performance is diverse. This paper discussed the so...It is difficult to develop the corresponding fault diagnosis system and the software reusability is bad because the engineering equipment types are so many and their performance is diverse. This paper discussed the solution to engineering equipment integrated fault diagnosis system based on component technology, put forward the sys- tem model and gave the system frame design process and working principle. The software was designed based on the three-layer hierarchy. It is easy to rease and maintain, and the operation of the software is simple. A kind of new theory and method to develop the engineering equipment fault diagnosis system for the future was provided.展开更多
目的:构建基于Android平台的电子信息系统,探讨其在手术室仪器设备电子化动态管理中的应用价值。方法:采用Java开发语言、SQL Server 2008 R2数据库开发工具、浏览器与服务器(B/S)架构,设置Linux内核层、运行层、函数库、应用框架和应...目的:构建基于Android平台的电子信息系统,探讨其在手术室仪器设备电子化动态管理中的应用价值。方法:采用Java开发语言、SQL Server 2008 R2数据库开发工具、浏览器与服务器(B/S)架构,设置Linux内核层、运行层、函数库、应用框架和应用层构建基于Android平台的电子信息系统。选取2023年4-9月上海健康医学院附属崇明医院手术室在用的145件仪器设备,基于Android平台电子信息系统应用前采用人工手工登记,对比Android平台电子信息系统应用前后手术室仪器设备管理质量评分、运行质量和管理人员能力评分。结果:应用Android平台电子信息系统后仪器设备使用和归位速度、安全性能、维修速度和清洁质量评分分别为(39.01±1.38)分、(39.79±1.05)分、(38.85±1.22)分和(38.49±2.41)分,均明显高于应用前,其差异有统计学意义(t=3.313、19.407、26.957、8.010,P<0.05);应用Android平台电子信息系统后仪器设备开机率、成本效益增幅和社会效益增幅分别为(96.17±5.33)%、(7.93±1.15)%和(10.74±1.09)%,均高于应用前,仪器设备运转率为(9.21±1.35)%,低于应用前,其差异有统计学意义(t=9.386、59.769、47.946、27.078,P<0.05);应有Android平台电子信息系统后仪器设备管理人员的理论知识、操作能力和安全意识考核评分分别为(39.79±2.07)分、(39.11±2.18)分和(19.65±2.44)分,均明显高于应用前,其差异有统计学意义(t=9.261、7.645、7.253,P<0.05)。结论:基于Android平台的电子信息系统应用于手术室仪器设备管理,有助于实现仪器设备的电子化动态管理,提高仪器设备管理质量和管理水平。展开更多
In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagneti...In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagnetic storm time and low point displacement time interval respectively. After fitting of ten high spectral values to loga-rithmic functions,it is found that,by using same length of data,the spectral values at geomagnetic storm time in-crease apparently compared with those at normal time,especially at the high frequency segment. While low point displacement occurred,the spectral values at high frequency are approximate to those at normal time,but at period above 4 hours they are mostly lower than those at normal time. Comparison of accumulating of some FFT results at low point displacement and normal time shows that,spectral values at periods of 8.5 and 13.7 hours increase at low point displacement time relative to those at normal time. Compared with the images of Ne observed at DE-METER satellite,it is illustrated that the occurrence of geomagnetic low point displacement is well corresponding with the increase of Ne in ionosphere. Finally it was discussed about those spectral features and the occurrence mechanism of geomagnetic low point displacement.展开更多
When the electronic nose is used to identify different varieties of distilled liquors, the pattern recognition algorithm is chosen on the basis of the experience, which lacks the guiding principle. In this research, t...When the electronic nose is used to identify different varieties of distilled liquors, the pattern recognition algorithm is chosen on the basis of the experience, which lacks the guiding principle. In this research, the different brands of distilled spirits were identified using the pattern recognition algorithms (principal component analysis and the artificial neural network). The recognition rates of different algorithms were compared. The recognition rate of the Back Propagation Neural Network (BPNN) is the highest. Owing to the slow convergence speed of the BPNN, it tends easily to get into a local minimum. A chaotic BPNN was tried in order to overcome the disadvantage of the BPNN. The convergence speed of the chaotic BPNN is 75.5 times faster than that of the BPNN.展开更多
A comparison of three hydrometallurgical methods for selective recovery of copper from low-grade electric and electronic wastes was reported. Scraps were smelted to produce Cu?Zn?Sn?Ag alloy. Multiphase material wa...A comparison of three hydrometallurgical methods for selective recovery of copper from low-grade electric and electronic wastes was reported. Scraps were smelted to produce Cu?Zn?Sn?Ag alloy. Multiphase material was analyzed by SEM?EDS and XRD. The alloy was dissolved anodically with simultaneous metal electrodeposition using ammoniacal and sulfuric acid solutions or leached in ammonia?ammonium sulfate solution and then copper electrowinning was carried out. This resulted in the separation of metals, where lead, silver and tin accumulated mainly in the slimes, while copper was transferred to the electrolyte and then recovered on the cathode. The best conditions of the alloy treatment were obtained in the sulfuric acid, where the final product was metal of high purity (99% Cu) at the current efficiency of 90%. Ammoniacal leaching of the alloy led to the accumulation of copper ions in the electrolyte and further metal electrowinning, but the rate of the spontaneous dissolution was low. Anodic dissolution of the alloy in the ammonia?ammonium sulfate solution led to the unfavorable distribution of metals among the slime, electrolyte and cathodic deposit.展开更多
文摘Exploitation of sustainable energy sources requires the use of unique conversion and storage systems,such as solar panels,batteries,fuel cells,and electronic equipment.Thermal load management of these energy conversion and storage systems is one of their challenges and concerns.In this article,the thermal management of these systems using thermoelectric modules is reviewed.The results show that by choosing the right option to remove heat from the hot side of the thermoelectric modules,it will be a suitable local cooling,and the thermoelectric modules increase the power and lifespan of the system by reducing the spot temperature.Thermoelectric modules were effective in reducing panel temperature.They increase the time to reach a temperature above 50℃ in batteries by 3 to 4 times.Also,in their integration with fuel cells,they increase the power density of the fuel cell.
基金The authors thank D.Berger,D.Hofmann and C.Kupka in IFW Dresden for helpful technical support.H.R.acknowledges funding from the DFG(Deutsche Forschungsgemeinschaft)within grant number RE3973/1-1.Q.J.,H.R.and K.N.conceived the work.With the support from N.Y.and X.J.,Q.J.and T.G.fabricated the thermoelectric films and conducted the structural and compositional characterizations.Q.J.prepared microchips and fabricated the on-chip micro temperature controllers.Q.J.and N.P.carried out the temperature-dependent material and device performance measurements.Q.J.and H.R.performed the simulation and analytical calculations.Q.J.,H.R.and K.N.wrote the manuscript with input from the other coauthors.All the authors discussed the results and commented on the manuscript.
文摘Multidimensional integration and multifunctional com-ponent assembly have been greatly explored in recent years to extend Moore’s Law of modern microelectronics.However,this inevitably exac-erbates the inhomogeneity of temperature distribution in microsystems,making precise temperature control for electronic components extremely challenging.Herein,we report an on-chip micro temperature controller including a pair of thermoelectric legs with a total area of 50×50μm^(2),which are fabricated from dense and flat freestanding Bi2Te3-based ther-moelectric nano films deposited on a newly developed nano graphene oxide membrane substrate.Its tunable equivalent thermal resistance is controlled by electrical currents to achieve energy-efficient temperature control for low-power electronics.A large cooling temperature difference of 44.5 K at 380 K is achieved with a power consumption of only 445μW,resulting in an ultrahigh temperature control capability over 100 K mW^(-1).Moreover,an ultra-fast cooling rate exceeding 2000 K s^(-1) and excellent reliability of up to 1 million cycles are observed.Our proposed on-chip temperature controller is expected to enable further miniaturization and multifunctional integration on a single chip for microelectronics.
文摘As the“engine”of equipment continuous operation and repeated operation, equipment maintenance support plays a more prominent role in the confrontation of symmetrical combat systems. As the basis and guide for the planning and implementation of equipment maintenance tasks, the equipment damage measurement is an important guarantee for the effective implementation of maintenance support. Firstly,this article comprehensively analyses the influence factors to damage measurement from the enemy’s attributes, our attributes and the battlefield environment starting from the basic problem of wartime equipment damage measurement. Secondly, this article determines the key factors based on fuzzy comprehensive evaluation(FCE) and performed principal component analysis (PCA) on the key factors. Finally, the principal components representing more than 85%of the data features are taken as the input and the equipment damage quantity is taken as the output. The data are trained and tested by artificial neural network (ANN) and random forest (RF). In a word, FCE-PCA-RF can be used as a reference for the research of equipment damage estimation in wartime.
文摘We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response.
文摘In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.
文摘Nowadays, rapid technological progress influences the dependability of equipments and also causes rapid obsolescence. The mechatronic and electronic equipment components are mostly affected by obsolescence. A new challenger unit possesses identical functionalities, but with higher performances. This work aims to find the optimal number of components which should be replaced by new-type units, under budgetary constraints. In this work, the new challenger unit is characterized by lower energy consumption and the optimization steps are based on genetic algorithm (GA). The result shows the importance of this type of replacement in order to economize energy consumption and to deal with obsolescence.
文摘The purpose of this research was to develop a new approach in determination of overhaul and maintenance cost of loading equipment in surface mining. Two statistical models including univariate exponential regression (UER) and multivariate linear regression (MLR) were used in this study. Loading equipment parameters such as bucket capacity, machine weight, engine power, boom length, digging depth, and dumping height were considered as variables. The results obtained by models and mean absolute error rate indicate that these models can be applied as the useful tool in determination of overhaul and maintenance cost of loading equipment. The results of this study can be used by the decision-makers for the specific surface mining operations.
文摘Given the challenge of estimating or calculating quantities of waste electrical and electronic equipment(WEEE)in developing countries,this article focuses on predicting the WEEE generated by Cameroonian small and medium enterprises(SMEs)that are engaged in ISO 14001:2015 initiatives and consume electrical and electronic equipment(EEE)to enhance their performance and profitability.The methodology employed an exploratory approach involving the application of general equilibrium theory(GET)to contextualize the study and generate relevant parameters for deploying the random forest regression learning algorithm for predictions.Machine learning was applied to 80%of the samples for training,while simulation was conducted on the remaining 20%of samples based on quantities of EEE utilized over a specific period,utilization rates,repair rates,and average lifespans.The results demonstrate that the model’s predicted values are significantly close to the actual quantities of generated WEEE,and the model’s performance was evaluated using the mean squared error(MSE)and yielding satisfactory results.Based on this model,both companies and stakeholders can set realistic objectives for managing companies’WEEE,fostering sustainable socio-environmental practices.
基金Project(50605023) supported by the National Natural Science Foundation of China
文摘Considering two characteristics of compact heat dissipation room and high heat flux, a novel miniature capillary pumped loop (MCPL) for electronics cooling was proposed. MCPL consists of evaporator, condenser, vapor and liquid line dissipates heat by boiling and condensation of working fluids with no extra power consumption. Working fluid circulation is ensured by vapor pressure and capillary head. Saturated wick screens vapor and liquid, and ensures one-way flow of working fluid with no extra valve. In order to promote heat dissipation capacity of MCPL, the intensified boiling and condensation structures are embedded into evaporator and condenser respectively, which are useful to increasing boiling and condensation efficiency. Startup and run characteristics are tested by experiments in the condition of different power inputs and working fluids. MCPL is capable of dissipating 80 W of thermal energy and keeping the bottom substrate temperature of evaporator at 80 ℃.
文摘In view of the current reliability evaluation requirements of warship equipment based on component, this paper comprehensively considered the characteristics of components,and the component identification method, structural decomposition method,component architecture modeling method were studied for warship equipment software. Based on the characteristics of warship equipment component, this paper proposed a formal modeling language based on Petri nets to realize the modeling of component software architecture and laid a foundation for the reliability evaluation method research of warship equipment component.
文摘The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5~3 times as large as that of smooth chip at the same subcooling.
文摘High performance electromechanical equipment is widely used in various fields, such as national defense, industry and so on [ 1]. In addition, the technical level of high performance electromechanical equipment is the embodiment of the national level of science and technology.
文摘The basic principle and method of Grey Model prediction are presented. In view of the defects of general GM(1,1) model, an improved method is proposed. That is using the particle swarm optimization algorithm to obtain the best forecast dimension and using metabolism to make the model parameters adaptively change. Finally, the improved Grey Model is used to predict the fault of high voltage power supply circuit of a certain type of modern air-borne radar. The results which are computed and simulated by Matlab software show that the forecast precision of improved Grey Model is higher than that of original Grey Model.
文摘Rare earth elements (REEs), especially heavy rare earth elements (HREEs), are in demand for their current and emerging applications in advanced technologies. Here we perform computer-driven micro-mapping at the millimeter scale of the minerals that comprise Round Top Mountain, in west Texas, USA. This large rhyolite deposit is enriched in HREEs and such other critical elements as Li, Be, and U. Electron probe microanalysis of 2 × 2 mm areas of thin sections of the rhyolite produced individual maps of 16 elements. These were superimposed to generate a 16-element composition at each pixel. Principal components analysis of elements at each pixel identified the specific mineral at that site. The pixels were then relabeled as the appropriate minerals, thereby producing a single mineral map. The overall mineral composition of the 7 studied samples compared favorably with prior analyses of the Round Top deposit available in the literature. Likewise the range of porosity in the maps was consistent with that of previous direct measurements by water saturation. This new statistical and GIS-based technique provides a robust and unbiased approach to electron microprobe mapping. The study further showed that the high-value yttrofluorite grains exhibited little tendency to cluster with other late-stage trace minerals and that the samples extended the previously documented overall homogeneity of the deposit at field scale to this microscopic scale.
文摘In this paper, the failure mechanism of electronic equipment was analysed.Aiming at the limitation of traditional maintenance modes, modern maintenance strategy was putforward on the basis of reliability-centered maintenance ( RCM) combined with condition-basedmaintenance ( CBM) and maintenance efficiency review (MER). A maintenance management informationsystem was constructed for electronic equipment for the purpose of failure analysis, reliabilityevaluation, and maintenance decisions such as time, mode, and plan. The best maintenance time couldbe predicted with failure analysis and reliability evaluation, which was mainly influenced byenvironmental stress. Suitable maintenance modes should be determined from equipment importance,failure aftereffect, maintenance condition, and economical power so as to ensure equipmentreliability and decrease the requirement of the maintenance source.
文摘It is difficult to develop the corresponding fault diagnosis system and the software reusability is bad because the engineering equipment types are so many and their performance is diverse. This paper discussed the solution to engineering equipment integrated fault diagnosis system based on component technology, put forward the sys- tem model and gave the system frame design process and working principle. The software was designed based on the three-layer hierarchy. It is easy to rease and maintain, and the operation of the software is simple. A kind of new theory and method to develop the engineering equipment fault diagnosis system for the future was provided.
文摘目的:构建基于Android平台的电子信息系统,探讨其在手术室仪器设备电子化动态管理中的应用价值。方法:采用Java开发语言、SQL Server 2008 R2数据库开发工具、浏览器与服务器(B/S)架构,设置Linux内核层、运行层、函数库、应用框架和应用层构建基于Android平台的电子信息系统。选取2023年4-9月上海健康医学院附属崇明医院手术室在用的145件仪器设备,基于Android平台电子信息系统应用前采用人工手工登记,对比Android平台电子信息系统应用前后手术室仪器设备管理质量评分、运行质量和管理人员能力评分。结果:应用Android平台电子信息系统后仪器设备使用和归位速度、安全性能、维修速度和清洁质量评分分别为(39.01±1.38)分、(39.79±1.05)分、(38.85±1.22)分和(38.49±2.41)分,均明显高于应用前,其差异有统计学意义(t=3.313、19.407、26.957、8.010,P<0.05);应用Android平台电子信息系统后仪器设备开机率、成本效益增幅和社会效益增幅分别为(96.17±5.33)%、(7.93±1.15)%和(10.74±1.09)%,均高于应用前,仪器设备运转率为(9.21±1.35)%,低于应用前,其差异有统计学意义(t=9.386、59.769、47.946、27.078,P<0.05);应有Android平台电子信息系统后仪器设备管理人员的理论知识、操作能力和安全意识考核评分分别为(39.79±2.07)分、(39.11±2.18)分和(19.65±2.44)分,均明显高于应用前,其差异有统计学意义(t=9.261、7.645、7.253,P<0.05)。结论:基于Android平台的电子信息系统应用于手术室仪器设备管理,有助于实现仪器设备的电子化动态管理,提高仪器设备管理质量和管理水平。
基金National Science and Technology Program (2006BAC011302-04-02)Basic Research Project in Institute of Earthquake Science,China Earthquake Administration.
文摘In this paper,Changli station in Hebei Province was taken as an example,in which the minute data of geomagnetic Z component was used to analyze the spectral values of its main frequencies during normal time,geomagnetic storm time and low point displacement time interval respectively. After fitting of ten high spectral values to loga-rithmic functions,it is found that,by using same length of data,the spectral values at geomagnetic storm time in-crease apparently compared with those at normal time,especially at the high frequency segment. While low point displacement occurred,the spectral values at high frequency are approximate to those at normal time,but at period above 4 hours they are mostly lower than those at normal time. Comparison of accumulating of some FFT results at low point displacement and normal time shows that,spectral values at periods of 8.5 and 13.7 hours increase at low point displacement time relative to those at normal time. Compared with the images of Ne observed at DE-METER satellite,it is illustrated that the occurrence of geomagnetic low point displacement is well corresponding with the increase of Ne in ionosphere. Finally it was discussed about those spectral features and the occurrence mechanism of geomagnetic low point displacement.
基金the Science and Technology Plan Projects, Department of Education of Jilin Province, P R China (Grant no. 2006026)
文摘When the electronic nose is used to identify different varieties of distilled liquors, the pattern recognition algorithm is chosen on the basis of the experience, which lacks the guiding principle. In this research, the different brands of distilled spirits were identified using the pattern recognition algorithms (principal component analysis and the artificial neural network). The recognition rates of different algorithms were compared. The recognition rate of the Back Propagation Neural Network (BPNN) is the highest. Owing to the slow convergence speed of the BPNN, it tends easily to get into a local minimum. A chaotic BPNN was tried in order to overcome the disadvantage of the BPNN. The convergence speed of the chaotic BPNN is 75.5 times faster than that of the BPNN.
基金Project(NNOTECH-2/IN2/18/181960/NCBR)supported by the National Centre for Research and Development,Poland
文摘A comparison of three hydrometallurgical methods for selective recovery of copper from low-grade electric and electronic wastes was reported. Scraps were smelted to produce Cu?Zn?Sn?Ag alloy. Multiphase material was analyzed by SEM?EDS and XRD. The alloy was dissolved anodically with simultaneous metal electrodeposition using ammoniacal and sulfuric acid solutions or leached in ammonia?ammonium sulfate solution and then copper electrowinning was carried out. This resulted in the separation of metals, where lead, silver and tin accumulated mainly in the slimes, while copper was transferred to the electrolyte and then recovered on the cathode. The best conditions of the alloy treatment were obtained in the sulfuric acid, where the final product was metal of high purity (99% Cu) at the current efficiency of 90%. Ammoniacal leaching of the alloy led to the accumulation of copper ions in the electrolyte and further metal electrowinning, but the rate of the spontaneous dissolution was low. Anodic dissolution of the alloy in the ammonia?ammonium sulfate solution led to the unfavorable distribution of metals among the slime, electrolyte and cathodic deposit.