The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices...The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices that can flexibly control active and reactive power flows.With the exception of active power output,photovoltaic(PV)devices can provide reactive power compensation through an inverter.Thus,a synergetic optimization operation method for SOP and PV in a distribution network is proposed.A synergetic optimization model was developed.The voltage deviation,network loss,and ratio of photovoltaic abandonment were selected as the objective functions.The PV model was improved by considering the three reactive power output modes of the PV inverter.Both the load fluctuation and loss of the SOP were considered.Three multi-objective optimization algorithms were used,and a compromise optimal solution was calculated.Case studies were conducted using an IEEE 33-node system.The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation.Synergetic optimization improves power control capability and flexibility,providing better power quality and PV consumption rate.展开更多
Package delivery via ridesharing provides appealing benefits of lower delivery cost and efficient vehicle usage.Most existing ridesharing systems operate the matching of ridesharing in a centralized manner,which may r...Package delivery via ridesharing provides appealing benefits of lower delivery cost and efficient vehicle usage.Most existing ridesharing systems operate the matching of ridesharing in a centralized manner,which may result in the single point of failure once the controller breaks down or is under attack.To tackle such problems,our goal in this paper is to develop a blockchain-based package delivery ridesharing system,where decentralization is adopted to remove intermediaries and direct transactions between the providers and the requestors are allowed.To complete the matching process under decentralized structure,an Event-Triggered Distributed Deep Reinforcement Learning(ETDDRL)algorithm is proposed to generate/update the real-time ridesharing orders for the new coming ridesharing requests from a local view.Simulation results reveal the vast potential of the ETDDRL matching algorithm under the blockchain framework for the promotion of the ridesharing profits.Finally,we develop an application for Android-based terminals to verify the ETDDRL matching algorithm.展开更多
Light emitting diodes(LEDs)have accounted for most of the lighting market as the technology matures and costs continue to reduce.As a new type of e-waste,LED is a double-edged sword,as it contains not only precious an...Light emitting diodes(LEDs)have accounted for most of the lighting market as the technology matures and costs continue to reduce.As a new type of e-waste,LED is a double-edged sword,as it contains not only precious and rare metals but also organic packaging materials.In previous studies,LED recycling focused on recovering precious and strategic metals while ignoring harmful substances such as organic packaging materials.Unlike crushing and other traditional methods,hydrothermal treatment can provide an environment-friendly process for decomposing packaging materials.This work developed a closed reaction vessel,where the degradation rate of plastic polyphthalamide(PPA)was close to 100%,with nano-TiO_(2)encapsulated in plastic PPA being efficiently recovered,while metals contained in LED were also recycled efficiently.Besides,the role of water in plastic PPA degradation that has been overlooked in current studies was explored and speculated in detail in this work.Environmental impact assessment revealed that the proposed recycling route for waste LED could significantly reduce the overall environmental impact compared to the currently published processes.Especially the developed method could reduce more than half the impact of global warming.Furthermore,this research provides a theoretical basis and a promising method for recycling other plastic-packaged e-waste devices,such as integrated circuits.展开更多
Ensuring high product quality is of paramount importance in pharmaceutical drug manufacturing,as it is subject to rigorous regulatory practices.This study presents a research focused on the development of an on-line d...Ensuring high product quality is of paramount importance in pharmaceutical drug manufacturing,as it is subject to rigorous regulatory practices.This study presents a research focused on the development of an on-line detection method and system for identifying surface defects in pharmaceutical products packaged in aluminum-plastic blisters.Firstly,the aluminum-plastic blister packages exhibit multi-scale features and inter-class indistinction.To address this,the deep semantic network with boundary refinement(DSN-BR)model is proposed,which leverages semantic segmentation domain knowledge,to accurately segment the defects in pixel level.Additionally,a specialized image acquisition module that minimizes the impact of ambient light is established,ensuring high-quality image capture.Finally,the image acquisition module,image detection module,and data management module are designed to construct a comprehensive online surface defect detection system.To validate the effectiveness of our approach,we employ a real dataset for instance verification on the implemented system.The experimental results substantiate the outstanding performance of the DSN-BR,achieving the mean intersection over union(MIoU)of 90.5%.Furthermore,the proposed system achieves an inference speed of up to 14.12 f/s,while attaining an F1-Score of 98.25%.These results demonstrate that the system meets the actual needs of the enterprise and provides theoretical and methodological support for intelligent inspection of product surface quality.By standardizing the control process of pharmaceutical manufacturing and improving the management capability of the manufacturing process,our approach holds significant market application prospects.展开更多
Objective:The main objective of this study is to investigate the effectiveness of the stress management intervention package in improving stress-related burnout.Materials and Methods:An experimental study was done on ...Objective:The main objective of this study is to investigate the effectiveness of the stress management intervention package in improving stress-related burnout.Materials and Methods:An experimental study was done on 300 nurses selected by a nonprobability convenience sampling technique and a quasi-experimental one-group pre-and posttest research design was utilized.Modified expanded nurses stress scale and self-structured three-point Likert scale on the challenges that nurses may face following stressful life events utilized to collect information.The nurses signed up for six interactive sessions on various stress-coping methods by utilizing a variety of teaching strategies such as lecture cum discussion,video slides,group work,and direct interaction with the experts to explore stress-related issues.Results:Continuous stress affects both the body and the mind,causing psychosomatic symptoms.Data found that 2%to 10%of nurses frequently suffered with physical symptoms such as exhaustion,backache,acidity,headache,shoulder stiffness,and insomnia.Following the intervention,the number of nurses who had these symptoms frequently and sometimes decreased.Previously,10%of nurses experienced emotional symptoms frequently;however,after intervention,this figure was reduced to<2%.The greatest proportion of nurses(18%)reported frequently worrying,while 1.3%expressed frequent worrying after intervention.Maximum(5%)of nurses had a tendency to eat too little or too much;this has been reduced to 0.3%after the intervention.The intervention package on stress management significantly improved nurses’Conclusion:An intervention package for stress management was helpful in lowering physical,emotional,psychological,and behavioral stress-related symptoms among nurses.展开更多
As the increasing desire for more compact,portable devices outpaces Moore’s law,innovation in packaging and system design has played a significant role in the continued miniaturization of electronic systems.Integrati...As the increasing desire for more compact,portable devices outpaces Moore’s law,innovation in packaging and system design has played a significant role in the continued miniaturization of electronic systems.Integrating more active and passive components into the package itself,as the case for system-on-package(SoP),has shown very promising results in overall size reduction and increased performance of electronic systems.With this ability to shrink electrical systems comes the many challenges of sustaining,let alone improving,reliability and performance.The fundamental signal,power,and thermal integrity issues are discussed in detail,along with published techniques from around the industry to mitigate these issues in SoP applications.展开更多
Modern electronic circuit requires compact,multifunctional technology in communication systems.However,it is very difficult due to the limitations in passive component miniaturization and the complication of fabricati...Modern electronic circuit requires compact,multifunctional technology in communication systems.However,it is very difficult due to the limitations in passive component miniaturization and the complication of fabrication process.The bandpass filter is one of the most important passive components in millimeter(mm)-wave communication system,attracting significant interest in three-dimension(3D) miniaturized design,which is few reported.In this paper,a bandpass filter structure using low-temperature co-fired ceramic(LTCC) technology,which is fully integrated in a system-in package(SIP) communication module,is presented for miniaturized and high reliable mm-wave application.The bandpass filter with 3D end-coupled microstrip resonators is implemented in order to achieve a high performance bandwidth characteristic.Specifically,all of the resonators are embedded into different ceramic layers to decrease the insertion loss and enhance the out-of-band rejection performance by optimizing the coupling coefficient and the coupling strength.A fence structure,which is formed by metal-filled via array with the gap less than quarter wavelength,is placed around the embedded bandpass filter to avoid electromagnetic(EM) interference problem in multilayer structure.This structural model is validated through actual LTCC process.The bandpass filter is successfully manufactured by modifying the co-fireablity characteristics,adjusting the sintering profile,releasing the interfacial stress,and reducing the shrinkage mismatch with different materials.Measured results show good performance and agree well with the high frequency EM full wave simulation.The influence of layer thickness and dielectric constant on the frequency response in fabricated process is analyzed,where thicker ceramic sheets let the filter response shift to higher frequency.Moreover,measured S-parameters denote the center frequency is also strongly influenced by the variation of ceramic material's dielectric constants.By analyzing the relationship between the characteristics of the ceramic tape and the center frequency of the filter,both theoretical and experimental data are accumulated for broadening application filed.With the coupling resonators embedded into the ceramic layers,the bandpass filter exhibits advantages of small size and high reliability compared to conventional planar filter structure,which makes the bandpass filter suitable for SIP communicational application.展开更多
A 3D fan-out packaging method for the integration of 5G communication RF microsystem and antenna is studied.First of all,through the double-sided wiring technology on the glass wafer,the fabrication of 5G antenna arra...A 3D fan-out packaging method for the integration of 5G communication RF microsystem and antenna is studied.First of all,through the double-sided wiring technology on the glass wafer,the fabrication of 5G antenna array is realized.Then the low power devices such as through silicon via(TSV)transfer chips,filters and antenna tuners are flip-welded on the glass wafer,and the glass wafer is reformed into a wafer permanently bonded with glass and resin by the injection molding process with resin material.Finally,the thinning resin surface leaks out of the TSV transfer chip,the rewiring is carried out on the resin surface,and then the power amplifier,low-noise amplifier,power management and other devices are flip-welded on the resin wafer surface.A ball grid array(BGA)is implanted to form the final package.The loss of the RF transmission line is measured by using the RF millimeter wave probe table.The results show that the RF transmission loss from the chip end to the antenna end in the fan-out package is very small,and it is only 0.26 dB/mm when working in 60 GHz.A slot coupling antenna is designed on the glass wafer.The antenna can operate at 60 GHz and the maximum gain can reach 6 dB within the working bandwidth.This demonstration successfully provides a feasible solution for the 3D fan-out integration of RF microsystem and antenna in 5G communications.展开更多
The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage peri...The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage period. The results showed that the losses of weight and vitamin C were significantly reduced. The accumula-tion of crude fiber was effectively inhibited. But protein content was maintained at a low level and the rotting more serious of Chinese cabbage at the end of the stor-age packaged with the fresh keeping bags.展开更多
To reduce the drift error existing in the output signal of fiber optic gyroscopes (FOG), a mathematical model of the FOG output signal is set up; the error characteristics of the FOG output signal are analyzed, and ...To reduce the drift error existing in the output signal of fiber optic gyroscopes (FOG), a mathematical model of the FOG output signal is set up; the error characteristics of the FOG output signal are analyzed, and semi-soft threshold filtering is chosen based on the comparison of hard threshold and soft threshold filtering. The semi-soft threshold wavelet package filtering method is applied in the filtering of the FOG output signal. Experiments of the stationary and dynamic FOG output signals filtered with the wavelet package analysis are carried out in a lab environment, respectively. Experiments done with the real-time measured FOG signal show that the method of semi-soft threshold wavelet package filtering reduces the mean square error from 5 (°)/h to 1 (°)/h, so it is effective in eliminating the white noises and the fractal noises existing in the FOG. The novel method proposed here is proved valid in reducing the FOG drift error, satisfying the technical demands of high precision and realtime processing.展开更多
High performance can be obtained for the integrated power electronics module(IPEM) by using a three-dimensional packaging structure instead of a planar structure. A three- dimensional packaged half bridge-IPEM (HB-...High performance can be obtained for the integrated power electronics module(IPEM) by using a three-dimensional packaging structure instead of a planar structure. A three- dimensional packaged half bridge-IPEM (HB-IPEM), consisting of two chip scale packaged MOSFETs and the corresponding gate driver and protection circuits, is fabricated at the laboratory. The reliability of the IPEM is controlled from the shape design of solder joints and the control of assembly process parameters. The parasitic parameters are extracted using Agilent 4395A impedance analyzer for building the parasitic parameter model of the HB- IPEM. A 12 V/3 A output synchronous rectifier Buck converter using the HB-IPEM is built to test the electrical performance of the HB-IPEM. Low voltage spikes on two MOSFETs illustrate that the three-dimensional package of the HB-IPEM can decrease parasitic inductance. Temperature distribution simulation results of the HB-IPEM using FLOTHERM are given. Heat dissipation of the solder joints makes the peak junction temperature of the chip drop obviously. The package realizes three-dimensional heat dissipation and has better thermal management.展开更多
A model for modified-atmosphere packaging (MAP) systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was success...A model for modified-atmosphere packaging (MAP) systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was successfully verified by experiments with yellow peaches at 5,15 and 25 ℃ using two types of packaging films.A Michaelis-Menten type respiration model with noncompetitive inhibition mechanism due to CO2 was adopted while the respiration rates were measured with an improved permeable system method suitable for either steady or unsteady state.The applicability of the model in the design of MAP systems was demonstrated with a calculation to evaluate film specification and equilibrium concentrations of O2 and CO2 in the package containing yellow peaches.展开更多
In electronics packaging the time-pressure dispensing system is widely usedto squeeze the adhesive fluid in a syringe onto boards or substrates with the pressurized air.However, complexity of the process, which includ...In electronics packaging the time-pressure dispensing system is widely usedto squeeze the adhesive fluid in a syringe onto boards or substrates with the pressurized air.However, complexity of the process, which includes the air-fluid coupling and the nonlinearuncertainties, makes it difficult to have a consistent process performance. An integrated dispensingprocess model is first introduced and then its input-output regression relationship is used todesign a run to run control methodology for this process. The controller takes EWMA scheme and itsstability region is given. Experimental results verify the effectiveness of the proposed run to runcontrol method for dispensing process.展开更多
An ultrasonic test of spot welding for stainless steel is conducted. Based on wavelet packet decomposition, the ultrasonic echo signal has been analyzed deeply in time - frequency domain, which can easily distinguish ...An ultrasonic test of spot welding for stainless steel is conducted. Based on wavelet packet decomposition, the ultrasonic echo signal has been analyzed deeply in time - frequency domain, which can easily distinguish the nugget from the corona bond. The 2D C-scan images produced by ultrasonic C scan which contribute to quantitatively calculate the nugget diameter for the computer are further analyzed. The spot welding nugget diameter can be automatically obtained by image enhancement, edge detection and equivalent diameter algorithm procedure. The ultrasonic detection values in this paper show good agreement with the metallographic measured values. The mean value of normal distribution curve is 0.006 67, and the standard deviation is 0.087 11. Ultrasonic C-scan test based on wavelet packet signal analysis is of high accuracy and stability.展开更多
The finite element method(FEM) is used to analyze the effects of lead widths and pitches on reliability of soldered joints. The optimum simulation for QFP devices is also researched. The results indicate that when t...The finite element method(FEM) is used to analyze the effects of lead widths and pitches on reliability of soldered joints. The optimum simulation for QFP devices is also researched. The results indicate that when the lead pitches are the same, the maximum equivalent stress of the soldered joints increases with the increasing of lead widths, while the reliability of the soldered joints reduces. When the lead widths are the same, the maximum equivalent stress of the soldered joints doesn't decrease completely with the increasing of lead pitches, a minimum value of the maximum equivalent stress values exists in all the curves. Under this condition the maximum equivalent stress of the soldewed joints is relatively the least, the reliability of soldered joints is high and the assembly is excellent. The simulating results indicate the best parameter: The lead width is 0.2 mm and lead pitch is 0.3 mm (the distance between two leads is 0.1 mm), which are benefited for the micromation of QFP devices now. The minimum value of the maximum equivalent stress of soldered joints exists while lead width is 0.25 mm and lead pitch is 0.35 mm (the distance between two leads is 0.1 mm), the devices can serve for a long time and the reliability is the highest, the assembly is excellent. The simulating results also indicate the fact that the lead width is 0.15 mm and lead pitch is 0.2 mm maybe the limit of QFP, which is significant for the high lead count and micromation of assembly.展开更多
基金supported by the Science and Technology Project of SGCC(kj2022-075).
文摘The integration of distributed generation brings in new challenges for the operation of distribution networks,including out-of-limit voltage and power flow control.Soft open points(SOP)are new power electronic devices that can flexibly control active and reactive power flows.With the exception of active power output,photovoltaic(PV)devices can provide reactive power compensation through an inverter.Thus,a synergetic optimization operation method for SOP and PV in a distribution network is proposed.A synergetic optimization model was developed.The voltage deviation,network loss,and ratio of photovoltaic abandonment were selected as the objective functions.The PV model was improved by considering the three reactive power output modes of the PV inverter.Both the load fluctuation and loss of the SOP were considered.Three multi-objective optimization algorithms were used,and a compromise optimal solution was calculated.Case studies were conducted using an IEEE 33-node system.The simulation results indicated that the SOP and PVs complemented each other in terms of active power transmission and reactive power compensation.Synergetic optimization improves power control capability and flexibility,providing better power quality and PV consumption rate.
基金supported by National Natural Science Foundation of China(Grant No.62271073 and 61971066)Beijing Natural Science Foundation(L212003)the National Youth Top-notch Talent Support Program.
文摘Package delivery via ridesharing provides appealing benefits of lower delivery cost and efficient vehicle usage.Most existing ridesharing systems operate the matching of ridesharing in a centralized manner,which may result in the single point of failure once the controller breaks down or is under attack.To tackle such problems,our goal in this paper is to develop a blockchain-based package delivery ridesharing system,where decentralization is adopted to remove intermediaries and direct transactions between the providers and the requestors are allowed.To complete the matching process under decentralized structure,an Event-Triggered Distributed Deep Reinforcement Learning(ETDDRL)algorithm is proposed to generate/update the real-time ridesharing orders for the new coming ridesharing requests from a local view.Simulation results reveal the vast potential of the ETDDRL matching algorithm under the blockchain framework for the promotion of the ridesharing profits.Finally,we develop an application for Android-based terminals to verify the ETDDRL matching algorithm.
基金supported by the National Natural Science Foundation of China(52270132).
文摘Light emitting diodes(LEDs)have accounted for most of the lighting market as the technology matures and costs continue to reduce.As a new type of e-waste,LED is a double-edged sword,as it contains not only precious and rare metals but also organic packaging materials.In previous studies,LED recycling focused on recovering precious and strategic metals while ignoring harmful substances such as organic packaging materials.Unlike crushing and other traditional methods,hydrothermal treatment can provide an environment-friendly process for decomposing packaging materials.This work developed a closed reaction vessel,where the degradation rate of plastic polyphthalamide(PPA)was close to 100%,with nano-TiO_(2)encapsulated in plastic PPA being efficiently recovered,while metals contained in LED were also recycled efficiently.Besides,the role of water in plastic PPA degradation that has been overlooked in current studies was explored and speculated in detail in this work.Environmental impact assessment revealed that the proposed recycling route for waste LED could significantly reduce the overall environmental impact compared to the currently published processes.Especially the developed method could reduce more than half the impact of global warming.Furthermore,this research provides a theoretical basis and a promising method for recycling other plastic-packaged e-waste devices,such as integrated circuits.
文摘Ensuring high product quality is of paramount importance in pharmaceutical drug manufacturing,as it is subject to rigorous regulatory practices.This study presents a research focused on the development of an on-line detection method and system for identifying surface defects in pharmaceutical products packaged in aluminum-plastic blisters.Firstly,the aluminum-plastic blister packages exhibit multi-scale features and inter-class indistinction.To address this,the deep semantic network with boundary refinement(DSN-BR)model is proposed,which leverages semantic segmentation domain knowledge,to accurately segment the defects in pixel level.Additionally,a specialized image acquisition module that minimizes the impact of ambient light is established,ensuring high-quality image capture.Finally,the image acquisition module,image detection module,and data management module are designed to construct a comprehensive online surface defect detection system.To validate the effectiveness of our approach,we employ a real dataset for instance verification on the implemented system.The experimental results substantiate the outstanding performance of the DSN-BR,achieving the mean intersection over union(MIoU)of 90.5%.Furthermore,the proposed system achieves an inference speed of up to 14.12 f/s,while attaining an F1-Score of 98.25%.These results demonstrate that the system meets the actual needs of the enterprise and provides theoretical and methodological support for intelligent inspection of product surface quality.By standardizing the control process of pharmaceutical manufacturing and improving the management capability of the manufacturing process,our approach holds significant market application prospects.
文摘Objective:The main objective of this study is to investigate the effectiveness of the stress management intervention package in improving stress-related burnout.Materials and Methods:An experimental study was done on 300 nurses selected by a nonprobability convenience sampling technique and a quasi-experimental one-group pre-and posttest research design was utilized.Modified expanded nurses stress scale and self-structured three-point Likert scale on the challenges that nurses may face following stressful life events utilized to collect information.The nurses signed up for six interactive sessions on various stress-coping methods by utilizing a variety of teaching strategies such as lecture cum discussion,video slides,group work,and direct interaction with the experts to explore stress-related issues.Results:Continuous stress affects both the body and the mind,causing psychosomatic symptoms.Data found that 2%to 10%of nurses frequently suffered with physical symptoms such as exhaustion,backache,acidity,headache,shoulder stiffness,and insomnia.Following the intervention,the number of nurses who had these symptoms frequently and sometimes decreased.Previously,10%of nurses experienced emotional symptoms frequently;however,after intervention,this figure was reduced to<2%.The greatest proportion of nurses(18%)reported frequently worrying,while 1.3%expressed frequent worrying after intervention.Maximum(5%)of nurses had a tendency to eat too little or too much;this has been reduced to 0.3%after the intervention.The intervention package on stress management significantly improved nurses’Conclusion:An intervention package for stress management was helpful in lowering physical,emotional,psychological,and behavioral stress-related symptoms among nurses.
文摘As the increasing desire for more compact,portable devices outpaces Moore’s law,innovation in packaging and system design has played a significant role in the continued miniaturization of electronic systems.Integrating more active and passive components into the package itself,as the case for system-on-package(SoP),has shown very promising results in overall size reduction and increased performance of electronic systems.With this ability to shrink electrical systems comes the many challenges of sustaining,let alone improving,reliability and performance.The fundamental signal,power,and thermal integrity issues are discussed in detail,along with published techniques from around the industry to mitigate these issues in SoP applications.
基金supported by Research Fund for the Doctoral Program of Higher Education of China(Grant No.20060614021)Sichuan Provincial Fundamental Research of China(Grant No.2008JY0057),Fundamental Research Funds for the Central Universities of China(Grant No.ZYGX2009J091)
文摘Modern electronic circuit requires compact,multifunctional technology in communication systems.However,it is very difficult due to the limitations in passive component miniaturization and the complication of fabrication process.The bandpass filter is one of the most important passive components in millimeter(mm)-wave communication system,attracting significant interest in three-dimension(3D) miniaturized design,which is few reported.In this paper,a bandpass filter structure using low-temperature co-fired ceramic(LTCC) technology,which is fully integrated in a system-in package(SIP) communication module,is presented for miniaturized and high reliable mm-wave application.The bandpass filter with 3D end-coupled microstrip resonators is implemented in order to achieve a high performance bandwidth characteristic.Specifically,all of the resonators are embedded into different ceramic layers to decrease the insertion loss and enhance the out-of-band rejection performance by optimizing the coupling coefficient and the coupling strength.A fence structure,which is formed by metal-filled via array with the gap less than quarter wavelength,is placed around the embedded bandpass filter to avoid electromagnetic(EM) interference problem in multilayer structure.This structural model is validated through actual LTCC process.The bandpass filter is successfully manufactured by modifying the co-fireablity characteristics,adjusting the sintering profile,releasing the interfacial stress,and reducing the shrinkage mismatch with different materials.Measured results show good performance and agree well with the high frequency EM full wave simulation.The influence of layer thickness and dielectric constant on the frequency response in fabricated process is analyzed,where thicker ceramic sheets let the filter response shift to higher frequency.Moreover,measured S-parameters denote the center frequency is also strongly influenced by the variation of ceramic material's dielectric constants.By analyzing the relationship between the characteristics of the ceramic tape and the center frequency of the filter,both theoretical and experimental data are accumulated for broadening application filed.With the coupling resonators embedded into the ceramic layers,the bandpass filter exhibits advantages of small size and high reliability compared to conventional planar filter structure,which makes the bandpass filter suitable for SIP communicational application.
文摘A 3D fan-out packaging method for the integration of 5G communication RF microsystem and antenna is studied.First of all,through the double-sided wiring technology on the glass wafer,the fabrication of 5G antenna array is realized.Then the low power devices such as through silicon via(TSV)transfer chips,filters and antenna tuners are flip-welded on the glass wafer,and the glass wafer is reformed into a wafer permanently bonded with glass and resin by the injection molding process with resin material.Finally,the thinning resin surface leaks out of the TSV transfer chip,the rewiring is carried out on the resin surface,and then the power amplifier,low-noise amplifier,power management and other devices are flip-welded on the resin wafer surface.A ball grid array(BGA)is implanted to form the final package.The loss of the RF transmission line is measured by using the RF millimeter wave probe table.The results show that the RF transmission loss from the chip end to the antenna end in the fan-out package is very small,and it is only 0.26 dB/mm when working in 60 GHz.A slot coupling antenna is designed on the glass wafer.The antenna can operate at 60 GHz and the maximum gain can reach 6 dB within the working bandwidth.This demonstration successfully provides a feasible solution for the 3D fan-out integration of RF microsystem and antenna in 5G communications.
基金Supported by the Major State Research Development Program of China(2016YFD04013)~~
文摘The effect of freshness protection package on Chinese cabbage placed in the self-made shelf in ventilated storage was investigated, and the physiological-qual-ity indexes change were determined during the storage period. The results showed that the losses of weight and vitamin C were significantly reduced. The accumula-tion of crude fiber was effectively inhibited. But protein content was maintained at a low level and the rotting more serious of Chinese cabbage at the end of the stor-age packaged with the fresh keeping bags.
基金Pre-Research Program of General Armament Departmentduring the11th Five-Year Plan Period(No.51309020503)the National De-fense Basic Research Program of China(973 Program)(No.973-61334)+1 种基金the National Natural Science Foundation of China(No.50575042)Specialized Research Fund for the Doctoral Program of Higher Education ( No.20050286026).
文摘To reduce the drift error existing in the output signal of fiber optic gyroscopes (FOG), a mathematical model of the FOG output signal is set up; the error characteristics of the FOG output signal are analyzed, and semi-soft threshold filtering is chosen based on the comparison of hard threshold and soft threshold filtering. The semi-soft threshold wavelet package filtering method is applied in the filtering of the FOG output signal. Experiments of the stationary and dynamic FOG output signals filtered with the wavelet package analysis are carried out in a lab environment, respectively. Experiments done with the real-time measured FOG signal show that the method of semi-soft threshold wavelet package filtering reduces the mean square error from 5 (°)/h to 1 (°)/h, so it is effective in eliminating the white noises and the fractal noises existing in the FOG. The novel method proposed here is proved valid in reducing the FOG drift error, satisfying the technical demands of high precision and realtime processing.
基金Fok Ying Tung Education Foundation(No.91058)the Natural Science Foundation of High Education Institutions of Jiangsu Province(No.08KJD470004)Qing Lan Project of Jiangsu Province of 2008
文摘High performance can be obtained for the integrated power electronics module(IPEM) by using a three-dimensional packaging structure instead of a planar structure. A three- dimensional packaged half bridge-IPEM (HB-IPEM), consisting of two chip scale packaged MOSFETs and the corresponding gate driver and protection circuits, is fabricated at the laboratory. The reliability of the IPEM is controlled from the shape design of solder joints and the control of assembly process parameters. The parasitic parameters are extracted using Agilent 4395A impedance analyzer for building the parasitic parameter model of the HB- IPEM. A 12 V/3 A output synchronous rectifier Buck converter using the HB-IPEM is built to test the electrical performance of the HB-IPEM. Low voltage spikes on two MOSFETs illustrate that the three-dimensional package of the HB-IPEM can decrease parasitic inductance. Temperature distribution simulation results of the HB-IPEM using FLOTHERM are given. Heat dissipation of the solder joints makes the peak junction temperature of the chip drop obviously. The package realizes three-dimensional heat dissipation and has better thermal management.
基金The Start-up Research Fund for Teachers withDoctor s Degree by Shanghai University of Science and Technology (No.X530)the Key Subject Foundation of Shanghai Education Committee(PeriodⅣ).
文摘A model for modified-atmosphere packaging (MAP) systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was successfully verified by experiments with yellow peaches at 5,15 and 25 ℃ using two types of packaging films.A Michaelis-Menten type respiration model with noncompetitive inhibition mechanism due to CO2 was adopted while the respiration rates were measured with an improved permeable system method suitable for either steady or unsteady state.The applicability of the model in the design of MAP systems was demonstrated with a calculation to evaluate film specification and equilibrium concentrations of O2 and CO2 in the package containing yellow peaches.
基金This project is supported by National Natural Science Foundation of China (No.50390063, 50390064), Research Grant Council of HK SAR (CityU1086/01E)and City University of HK Applied R&D Project(No.9620002).
文摘In electronics packaging the time-pressure dispensing system is widely usedto squeeze the adhesive fluid in a syringe onto boards or substrates with the pressurized air.However, complexity of the process, which includes the air-fluid coupling and the nonlinearuncertainties, makes it difficult to have a consistent process performance. An integrated dispensingprocess model is first introduced and then its input-output regression relationship is used todesign a run to run control methodology for this process. The controller takes EWMA scheme and itsstability region is given. Experimental results verify the effectiveness of the proposed run to runcontrol method for dispensing process.
基金Funded by Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science & Engineering,Jilin University
文摘An ultrasonic test of spot welding for stainless steel is conducted. Based on wavelet packet decomposition, the ultrasonic echo signal has been analyzed deeply in time - frequency domain, which can easily distinguish the nugget from the corona bond. The 2D C-scan images produced by ultrasonic C scan which contribute to quantitatively calculate the nugget diameter for the computer are further analyzed. The spot welding nugget diameter can be automatically obtained by image enhancement, edge detection and equivalent diameter algorithm procedure. The ultrasonic detection values in this paper show good agreement with the metallographic measured values. The mean value of normal distribution curve is 0.006 67, and the standard deviation is 0.087 11. Ultrasonic C-scan test based on wavelet packet signal analysis is of high accuracy and stability.
基金This project is supported by Provincial Six Kind Skilled Personnel Project of Jiangsu,China(No.06-E-020).
文摘The finite element method(FEM) is used to analyze the effects of lead widths and pitches on reliability of soldered joints. The optimum simulation for QFP devices is also researched. The results indicate that when the lead pitches are the same, the maximum equivalent stress of the soldered joints increases with the increasing of lead widths, while the reliability of the soldered joints reduces. When the lead widths are the same, the maximum equivalent stress of the soldered joints doesn't decrease completely with the increasing of lead pitches, a minimum value of the maximum equivalent stress values exists in all the curves. Under this condition the maximum equivalent stress of the soldewed joints is relatively the least, the reliability of soldered joints is high and the assembly is excellent. The simulating results indicate the best parameter: The lead width is 0.2 mm and lead pitch is 0.3 mm (the distance between two leads is 0.1 mm), which are benefited for the micromation of QFP devices now. The minimum value of the maximum equivalent stress of soldered joints exists while lead width is 0.25 mm and lead pitch is 0.35 mm (the distance between two leads is 0.1 mm), the devices can serve for a long time and the reliability is the highest, the assembly is excellent. The simulating results also indicate the fact that the lead width is 0.15 mm and lead pitch is 0.2 mm maybe the limit of QFP, which is significant for the high lead count and micromation of assembly.