The downlink energy-efficient transmission schedule with non-ideal circuit power over Wreless networks involving a single transmitter and multiple receivers was investigated. According to the special structure of the ...The downlink energy-efficient transmission schedule with non-ideal circuit power over Wreless networks involving a single transmitter and multiple receivers was investigated. According to the special structure of the problem, a novel algorithm called OOSCPMR （the optimal offine scheduling with non-ideal circuit power for multi-receivers） is proposed, and the optimal offine solutions to optimize the energy- efficient transmission policy are found. The packets to be transmitted can be divided into two types where one type of packet is determined to be transmitted using the enrgy- efficient tansmission time, and the other type of packet is determined by the ID moveright algorithm. Finally, an energy-efficient online schedule is developed based on te proposed OOSCPMR algoriAm. Simulation results show that the optima offline transmission schedule provides te lower bound performance for the online tansmission schedule. The proposed optimal offline and online policy is more energy efficient than the existing schemes tat assume ideal circuit power.展开更多
A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of...A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of simulated moving bed chromatography (SMBC). The model equations were solved by a new efficient numerical technique of orthogonal collocation on finite elements with periodical movement of concentration vector. The simulated SMBC performance is in accordance with the experimental results reported in the literature for separation of l,1'-bi-2-naphthol enantiomers using SMBC. This model is useful for design, operation, optimization and scale-up of non-linear SMBC for chiral separations with significant non-ideal effects, especially for high solute concentration and small intraparticle diffusion coefficient or large chiral stationary phase particle.展开更多
Ammonium nitrate and fuel oil(ANFO)based explosive is a classic example of non-ideal high explosives.Its detonation is characterized by a strong dependence of detonation parameters on explosive charge diameter,presenc...Ammonium nitrate and fuel oil(ANFO)based explosive is a classic example of non-ideal high explosives.Its detonation is characterized by a strong dependence of detonation parameters on explosive charge diameter,presence and characteristics of confinement,as well as incomplete consumption of explosive at the sonic point.In this work we propose a detonation model based on the Wood-Kirkwood(WK)theory coupled with the thermochemical code EXPLO5 and supplemented with reaction rate models.Our objective is to analyze the validity of the model for highly non-ideal ANFO explosives,with emphasis on effect of reaction rate models.It was found that both single-step and two-step pressure-based models can be calibrated to reproduce experimental detonation velocity-charge radius data of ANFO at radii significantly above the failure radius(i.e.for D/D_(id)>~0.6).Single-step pressure-based model,with the pressure exponent equal to 1.4,proved to be the most accurate,even in the vicinity of the failure radius.The impact of the rate models is most evident on temporal(and spatial)distribution of flow parameters in detonation driving zone,especially when it comes to the conversion and width of detonation driving zone.展开更多
A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous...A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.展开更多
An expanding model of the confinement of non-ideal detonation of small charge is established on the basis of the nozzle theory.Making use of the expanding model,the analytic relationship of small charge detonation vel...An expanding model of the confinement of non-ideal detonation of small charge is established on the basis of the nozzle theory.Making use of the expanding model,the analytic relationship of small charge detonation velocity and the semi-empirical relationship of detonation pressure that both change with charge diameter and confinement condition are established.The detonation velocity and pressure of small charges are calculated and experimentally verified,and the detonation velocity deviation is less than 7% while the detonation pressure deviation is less than 9%.展开更多
In this paper a three degrees of freedom autoparametric system with limited power supply is investigated numerically. The system consists of the body, which is hung on a spring and a damper, and two pendulums connecte...In this paper a three degrees of freedom autoparametric system with limited power supply is investigated numerically. The system consists of the body, which is hung on a spring and a damper, and two pendulums connected by shape memory alloy （SMA） spring. Shape memory alloys have ability to change their material properties with temperature. A polynomial constitutive model is assumed to describe the behavior of the SMA spring. The non-ideal source of power adds one degree of freedom, so the system has four degrees of freedom. The equations of motion have been solved numerically and pseudoelastic effects associated with the martensitic phase transformation are studied. It is shown that in this type system one mode of vibrations might excite or damp another mode, and that except different kinds of periodic vibrations there may also appear chaotic vibrations. For the identification of the responses of the system＇s various techniques, including chaos techniques such as bifurcation diagrams and time histories, power spectral densities, Poincare maps and exponents of Lyapunov may be used.展开更多
Memristor has been widely studied in the field of neuromorphic computing and is considered to be a strong candidate to break the von Neumann bottleneck. However, the non-ideal characteristics of memristor seriously li...Memristor has been widely studied in the field of neuromorphic computing and is considered to be a strong candidate to break the von Neumann bottleneck. However, the non-ideal characteristics of memristor seriously limit its practical application. There are two sides to everything, and memristors are no exception. The non-ideal characteristics of memristors may become ideal in some applications. Genetic algorithm(GA) is a method to search for the optimal solution by simulating the process of biological evolution. It is widely used in the fields of machine learning, combinatorial optimization,and signal processing. In this paper, we simulate the biological evolutionary behavior in GA by using the non-ideal characteristics of memristors, based on which we design peripheral circuits and path planning algorithms based on memristor networks. The experimental results show that the non-ideal characteristics of memristor can well simulate the biological evolution behavior in GA.展开更多
Terahertz(THz) radiation can be generated due to the instability of THz plasma waves in field-effect transistors(FETs). In this work, we discuss the instability of THz plasma waves in the channel of FETs with spin and...Terahertz(THz) radiation can be generated due to the instability of THz plasma waves in field-effect transistors(FETs). In this work, we discuss the instability of THz plasma waves in the channel of FETs with spin and quantum effects under non-ideal boundary conditions. We obtain a linear dispersion relation by using the hydrodynamic equation, Maxwell equation and spin equation. The influence of source capacitance, drain capacitance, spin effects, quantum effects and channel width on the instability of THz plasma waves under the non-ideal boundary conditions is investigated in great detail. The results of numerical simulation show that the THz plasma wave is unstable when the drain capacitance is smaller than the source capacitance;the oscillation frequency with asymmetric boundary conditions is smaller than that under non-ideal boundary conditions;the instability gain of THz plasma waves becomes lower under non-ideal boundary conditions. This finding provides a new idea for finding efficient THz radiation sources and opens up a new mechanism for the development of THz technology.展开更多
In present paper, certain aspect of shock wave in non-ideal gas, when magnetic field is orthogonal to the trajectories of the gas particles and electrical conductivity is taken to be infinite, is investigated. Conside...In present paper, certain aspect of shock wave in non-ideal gas, when magnetic field is orthogonal to the trajectories of the gas particles and electrical conductivity is taken to be infinite, is investigated. Considering one-dimensional unsteady non-planer motion, basic equations, its general solution and formation of shock-wave, conservation laws and jumps conditions, variation of area of non-uniform cross section and analytical solution of strong non planer shock is obtained.展开更多
In the present work the widths of layers constituting the non-ideal superlattice are much bigger then the characteristic scales of space dispersion. In such a case the contribution of individual layers to gyrotropy ca...In the present work the widths of layers constituting the non-ideal superlattice are much bigger then the characteristic scales of space dispersion. In such a case the contribution of individual layers to gyrotropy can be regarded as independed. Thus the corresponding optical quantities can be expressed through the layers’ gyrotropic characteristics. This approach is applied to calculate the specific rotation angle of plane of polarization of light propagating through a nonideal 1D-superlattice, which varies in composition as well as in layers’ width. We carry out numerical calculation of the frequency dispersion of optical activity of a non-ideal superlattice, which includes impurity layers with point defects.展开更多
The effect of a constant current(CC)power supply on the CC ocean observation system is a problem that once was neglected.The dynamic characteristics of the CC power supply may have great influence on the whole system,...The effect of a constant current(CC)power supply on the CC ocean observation system is a problem that once was neglected.The dynamic characteristics of the CC power supply may have great influence on the whole system,especially the voltage behavior in the event of load change.This needs to be examined.In this paper,a method is introduced to check whether the CC power supply can satisfy the dynamic requirements of the CC ocean observation system.An equivalent model to describe the non-ideal CC power supply is presented,through which the dynamic characteristics can be standardized.To verify the feasibility of this model,a minimum system of a single node in the CC ocean observation system is constructed,from which the model is derived.Focusing on the power failure problem,the output voltage responses are performed and the models are validated.Through the model,the dynamic behavior of the CC power supply is checked in a practical design.展开更多
In renewable power generation systems,ensuring the synchronization of the inverter and the power grid is crucial for the stable operation of grid-connected inverters.Nowadays,the phase-locked loop(PLL)technology has b...In renewable power generation systems,ensuring the synchronization of the inverter and the power grid is crucial for the stable operation of grid-connected inverters.Nowadays,the phase-locked loop(PLL)technology has become a widely used grid synchronization method because of its simple implementation and robustness under various grid conditions.Even though a lot of PLLs have been proposed,an overview and comparative analysis of multiple PLLs can be helpful for practical applications.In addition,the weak grid condition is a great challenge for the system.Therefore,this study first presents an overview of the existing PLLs together with their general structures and basic working principles.Depending on the implementation of the phase detector,the PLL can be divided into three categories:power-based PLL(pPLL),orthogonal-signalgenerator-based PLL(OSG-PLL)and adaptive-filter-based PLL(AF-PLL).Then,from the above classification,seven typical single-phase PLLs are selected for further study.Finally,some test results are given,and a comprehensive evaluation of the selected PLLs under different grid conditions is conducted.展开更多
The separation of non-ideal mixtures using distillation can be an extremely complex process and there continues to be a need to further improve these techniques.A new method which combines extractive heterogeneous-aze...The separation of non-ideal mixtures using distillation can be an extremely complex process and there continues to be a need to further improve these techniques.A new method which combines extractive heterogeneous-azeotropic distillation(EHAD)and hydrophilic pervapora-tion(HPV)for the separation of non-ideal termary mixtures is demonstrated.This improved distillation method combines the benefits of heterogeneous-azeotropic and extractive distillations in one column but no added materials are needed as is usually the case with pervaporation.The separation of water-methanol-ethyl acetate and water-methanol-isopropyl acetate mixtures were investigated to demonstrate the accuracy of the combined EHAD/HPV technique.There is not currently an established treatment strategy for the separation of the second mixtures in the literature.These separation processes were rigorously modelled and optimized using a professional flowsheet.The objective functions were total cost and energy consumption and heat integration was also investigated.The verification of the process modelling was carried out using laboratory-scale measurements.Extractive heterogeneous-distillation combined with methanol dehydration was found to be more efficient than conventional distillation for the separation of these highly non-ideal mixtures.展开更多
GaN field-effect transistors(FET)have low conduction and switching losses in high-frequency(>MHz)resonant wireless power transfer systems.Nevertheless,such systems impose a unique stress on GaN FETs owing to their ...GaN field-effect transistors(FET)have low conduction and switching losses in high-frequency(>MHz)resonant wireless power transfer systems.Nevertheless,such systems impose a unique stress on GaN FETs owing to their non-ideal voltage waveforms.In this work,we report the observed non-ideal behavior in a 6.78 MHz magnetic resonant wireless transfer system that employs class-D GaN power amplifiers.The non-ideal waveform phenomenon existing at the output of the power amplifier is explained.The study analyzes the causes of this phenomenon,including the coupling coefficient k of the coil,the DC input voltage of the amplifier,and the load on the receiver.Each parameter is simulated and analyzed using LTspice.The influence of the phenomenon on the on-state resistance of the GaN device is proved in an experimental measurement,and the cause of the phenomenon is explained.The study combines a theoretical simulation and an experimental test to discuss the effect of this phenomenon on GaN power devices and proposes the corresponding solutions,which include the limitation of voltage,current,and power of the system,thermal management,and other protection measures.展开更多
SCAs （Switched Capacitor Arrays） have a wide range of uses, especially in high energy physics, nuclear science and astrophysics experiments. This paper presents a method of using a MOS capacitor as a sampling capaci...SCAs （Switched Capacitor Arrays） have a wide range of uses, especially in high energy physics, nuclear science and astrophysics experiments. This paper presents a method of using a MOS capacitor as a sampling capacitor to gain larger capacitance with small capacitor area in SCA design. It studies the non-ideal effects of the MOS capacitor and comes up with ways to reduce these adverse effects. A prototype SCA ASIC which uses a MOS capacitor to store the samples has been designed and tested to verify this method. The SCA integrates 32 channels and each has 64 cells and a readout amplifier. The stored voltage is converted to a pair of differential currents （~ 4 mA max） and multiplexed to the output. All the functionalities have been verified. The power consumption is less than 2 mW/ch. The INL of all the cells in one channel are better than 0.39%. The equivalent input noise of the SCA has been tested to be 2.2 mV with 625 kHz full-scale sine wave as input, sampling at 40 MSPS （Mega-samples per Second） and reading out at 5 MHz. The effective resolution is 8.8 bits considering 1 V dynamic range. The maximum sampling rate reaches up to 50 MSPS and readout rate of 15 MHz to keep noise smaller than 2.5 mV. The test results validate the feasibility of the MOS capacitor.展开更多
基于无线和电力线通信(power line communication,PLC)的双模通信可以实现二者优势互补,被广泛用于智能计量和电力物联网中。针对正交频分复用(orthogonal frequency division multiplexing,OFDM)双模通信系统在新能源低时延业务接入等...基于无线和电力线通信(power line communication,PLC)的双模通信可以实现二者优势互补,被广泛用于智能计量和电力物联网中。针对正交频分复用(orthogonal frequency division multiplexing,OFDM)双模通信系统在新能源低时延业务接入等应用,提出了一种计及非理想信道估计的OFDM子载波分集组合和功率自适应分配算法。首先建立了以业务数据量、传输功率等为约束,以总时延最小化为目标的功率自适应优化分配模型;接着在分集分组的基础上,利用鲸鱼优化算法和阈值回收进行功率优化分配,实现算法复杂度和性能的折中。仿真实验结果表明,提出的算法在满足速率等约束条件下,减小传输平均时延和稳定性,为台区设备状态监测等实时业务数据采集提供更高的性能保障。展开更多
Isobaric molar heat capacity affected by pressures for non-ideal gases is calculated theoretically at specified temperatures by means of gaseous equations of state,i.e.Redlish-Kwong(RK)Equation,SoaveRedlich-Kwong(SRK)...Isobaric molar heat capacity affected by pressures for non-ideal gases is calculated theoretically at specified temperatures by means of gaseous equations of state,i.e.Redlish-Kwong(RK)Equation,SoaveRedlich-Kwong(SRK)Equation,Peng-Robinson(PR)Equation,Virial Equation,coupled with Romberg numeric integral via solving the key obstacle(δV/δT)_(p),and integral(δ^(2)V/δT^(2))_(p).As an example,methane's C_(p)is calculated at constant 300 K but 1 MPa&10 MPa.The calculation results show that less than 2%relative errors occur in comparison with literature values at any specified temperatures and pressures if no phase change survives at elevated pressure P_(2)and temperature T,or when specified temperatures are greater than critical temperatures in spite of elevated pressures.However,greater errors would be present if gases were considered to be ideal,or if temperatures are lower than critical temperatures at elevated pressures(>10 MPa),because C_(p)is the function of both temperature and pressure.In particular,elevated pressures have significant effect on C_(p).展开更多
基金The National Natural Science Foundation of China(No.61571123,61521061)the National Science and Technology Major Project(No.2016ZX03001011-005)+1 种基金the Research Fund of National Mobile Communications Research Laboratory of Southeast University(No.2017A03)Qing Lan Project
文摘The downlink energy-efficient transmission schedule with non-ideal circuit power over Wreless networks involving a single transmitter and multiple receivers was investigated. According to the special structure of the problem, a novel algorithm called OOSCPMR （the optimal offine scheduling with non-ideal circuit power for multi-receivers） is proposed, and the optimal offine solutions to optimize the energy- efficient transmission policy are found. The packets to be transmitted can be divided into two types where one type of packet is determined to be transmitted using the enrgy- efficient tansmission time, and the other type of packet is determined by the ID moveright algorithm. Finally, an energy-efficient online schedule is developed based on te proposed OOSCPMR algoriAm. Simulation results show that the optima offline transmission schedule provides te lower bound performance for the online tansmission schedule. The proposed optimal offline and online policy is more energy efficient than the existing schemes tat assume ideal circuit power.
基金Supported by the National Natural Science Foundation of China(No.20206027)and the Natural Science Foundation of Zhejiang Province(No.202046).
文摘A non-linear non-ideal model, taking into account non-linear competitive isotherms, axial dispersion, film mass transfer, intraparticle diffusion, and port periodic switching, was developed to simulate the dynamics of simulated moving bed chromatography (SMBC). The model equations were solved by a new efficient numerical technique of orthogonal collocation on finite elements with periodical movement of concentration vector. The simulated SMBC performance is in accordance with the experimental results reported in the literature for separation of l,1'-bi-2-naphthol enantiomers using SMBC. This model is useful for design, operation, optimization and scale-up of non-linear SMBC for chiral separations with significant non-ideal effects, especially for high solute concentration and small intraparticle diffusion coefficient or large chiral stationary phase particle.
基金the Croatian Science Foundation(HRZZ),Croatia,under the projects IP-2019-04-1618 and I-2243-2017.
文摘Ammonium nitrate and fuel oil(ANFO)based explosive is a classic example of non-ideal high explosives.Its detonation is characterized by a strong dependence of detonation parameters on explosive charge diameter,presence and characteristics of confinement,as well as incomplete consumption of explosive at the sonic point.In this work we propose a detonation model based on the Wood-Kirkwood(WK)theory coupled with the thermochemical code EXPLO5 and supplemented with reaction rate models.Our objective is to analyze the validity of the model for highly non-ideal ANFO explosives,with emphasis on effect of reaction rate models.It was found that both single-step and two-step pressure-based models can be calibrated to reproduce experimental detonation velocity-charge radius data of ANFO at radii significantly above the failure radius(i.e.for D/D_(id)>~0.6).Single-step pressure-based model,with the pressure exponent equal to 1.4,proved to be the most accurate,even in the vicinity of the failure radius.The impact of the rate models is most evident on temporal(and spatial)distribution of flow parameters in detonation driving zone,especially when it comes to the conversion and width of detonation driving zone.
基金Project(JC200903180555A) supported by Shenzhen City Science and Technology Plan, China
文摘A novel control strategy for three-phase shunt active power filter (SAPF) was proposed to improve its performance under non-ideal mains voltages. The approach was inspired by our finding that the classic instantaneous reactive power theory based algorithm was unsatisfactory in terms of isolating positive sequence fundamental active components exactly under non-ideal mains voltages. So, a modified ip-iq reference current calculation method was presented. With usage of the new method, not only the positive sequence but also the fundamental active current components can be accurately isolated from load current. A deadbeat closed-loop control model is built in order to eliminate both delay error and tracking error between reference voltages and compensation voltages under unbalanced and distorted mains voltages. Computer simulation results show that the proposed strategy is effective with better tracking ability and lower total harmonic distortion (THD). The strategy is also applied to a 10 kV substation with a local electrolysis manganese plant injecting a large amount of harmonics into the power system, and is proved to be more practical and efficient.
文摘An expanding model of the confinement of non-ideal detonation of small charge is established on the basis of the nozzle theory.Making use of the expanding model,the analytic relationship of small charge detonation velocity and the semi-empirical relationship of detonation pressure that both change with charge diameter and confinement condition are established.The detonation velocity and pressure of small charges are calculated and experimentally verified,and the detonation velocity deviation is less than 7% while the detonation pressure deviation is less than 9%.
文摘In this paper a three degrees of freedom autoparametric system with limited power supply is investigated numerically. The system consists of the body, which is hung on a spring and a damper, and two pendulums connected by shape memory alloy （SMA） spring. Shape memory alloys have ability to change their material properties with temperature. A polynomial constitutive model is assumed to describe the behavior of the SMA spring. The non-ideal source of power adds one degree of freedom, so the system has four degrees of freedom. The equations of motion have been solved numerically and pseudoelastic effects associated with the martensitic phase transformation are studied. It is shown that in this type system one mode of vibrations might excite or damp another mode, and that except different kinds of periodic vibrations there may also appear chaotic vibrations. For the identification of the responses of the system＇s various techniques, including chaos techniques such as bifurcation diagrams and time histories, power spectral densities, Poincare maps and exponents of Lyapunov may be used.
基金supported by the National Natural Science Foundation of China (Grant Nos. 61976246 and U20A20227)the Natural Science Foundation of Chongqing, China (Grant No. cstc2020jcyj-msxm X0385)the National Key R&D Program of China (Grant Nos. 2018YFB130660 and 2018YFB1306604)。
文摘Memristor has been widely studied in the field of neuromorphic computing and is considered to be a strong candidate to break the von Neumann bottleneck. However, the non-ideal characteristics of memristor seriously limit its practical application. There are two sides to everything, and memristors are no exception. The non-ideal characteristics of memristors may become ideal in some applications. Genetic algorithm(GA) is a method to search for the optimal solution by simulating the process of biological evolution. It is widely used in the fields of machine learning, combinatorial optimization,and signal processing. In this paper, we simulate the biological evolutionary behavior in GA by using the non-ideal characteristics of memristors, based on which we design peripheral circuits and path planning algorithms based on memristor networks. The experimental results show that the non-ideal characteristics of memristor can well simulate the biological evolution behavior in GA.
基金funded by National Natural Science Foundation of China (No. 12065015)the Hongliu First-level Discipline Construction Project of Lanzhou University of Technology。
文摘Terahertz(THz) radiation can be generated due to the instability of THz plasma waves in field-effect transistors(FETs). In this work, we discuss the instability of THz plasma waves in the channel of FETs with spin and quantum effects under non-ideal boundary conditions. We obtain a linear dispersion relation by using the hydrodynamic equation, Maxwell equation and spin equation. The influence of source capacitance, drain capacitance, spin effects, quantum effects and channel width on the instability of THz plasma waves under the non-ideal boundary conditions is investigated in great detail. The results of numerical simulation show that the THz plasma wave is unstable when the drain capacitance is smaller than the source capacitance;the oscillation frequency with asymmetric boundary conditions is smaller than that under non-ideal boundary conditions;the instability gain of THz plasma waves becomes lower under non-ideal boundary conditions. This finding provides a new idea for finding efficient THz radiation sources and opens up a new mechanism for the development of THz technology.
文摘In present paper, certain aspect of shock wave in non-ideal gas, when magnetic field is orthogonal to the trajectories of the gas particles and electrical conductivity is taken to be infinite, is investigated. Considering one-dimensional unsteady non-planer motion, basic equations, its general solution and formation of shock-wave, conservation laws and jumps conditions, variation of area of non-uniform cross section and analytical solution of strong non planer shock is obtained.
文摘In the present work the widths of layers constituting the non-ideal superlattice are much bigger then the characteristic scales of space dispersion. In such a case the contribution of individual layers to gyrotropy can be regarded as independed. Thus the corresponding optical quantities can be expressed through the layers’ gyrotropic characteristics. This approach is applied to calculate the specific rotation angle of plane of polarization of light propagating through a nonideal 1D-superlattice, which varies in composition as well as in layers’ width. We carry out numerical calculation of the frequency dispersion of optical activity of a non-ideal superlattice, which includes impurity layers with point defects.
基金Project supported by the National Natural Science Foundation of China(No.41676089)the Natural Science Foundation of Zhejiang Province,China(No.LY18E090003)the Fundamental Research Funds for the Central Universities,China(No.2018QNA4005)。
文摘The effect of a constant current(CC)power supply on the CC ocean observation system is a problem that once was neglected.The dynamic characteristics of the CC power supply may have great influence on the whole system,especially the voltage behavior in the event of load change.This needs to be examined.In this paper,a method is introduced to check whether the CC power supply can satisfy the dynamic requirements of the CC ocean observation system.An equivalent model to describe the non-ideal CC power supply is presented,through which the dynamic characteristics can be standardized.To verify the feasibility of this model,a minimum system of a single node in the CC ocean observation system is constructed,from which the model is derived.Focusing on the power failure problem,the output voltage responses are performed and the models are validated.Through the model,the dynamic behavior of the CC power supply is checked in a practical design.
基金This work is supported in part by the National Natural Science Foundation of China(No.51807089,51877104)in part by the Natural Science Foundation of Jiangsu Province(No.BK20180432).
文摘In renewable power generation systems,ensuring the synchronization of the inverter and the power grid is crucial for the stable operation of grid-connected inverters.Nowadays,the phase-locked loop(PLL)technology has become a widely used grid synchronization method because of its simple implementation and robustness under various grid conditions.Even though a lot of PLLs have been proposed,an overview and comparative analysis of multiple PLLs can be helpful for practical applications.In addition,the weak grid condition is a great challenge for the system.Therefore,this study first presents an overview of the existing PLLs together with their general structures and basic working principles.Depending on the implementation of the phase detector,the PLL can be divided into three categories:power-based PLL(pPLL),orthogonal-signalgenerator-based PLL(OSG-PLL)and adaptive-filter-based PLL(AF-PLL).Then,from the above classification,seven typical single-phase PLLs are selected for further study.Finally,some test results are given,and a comprehensive evaluation of the selected PLLs under different grid conditions is conducted.
基金This work was supported by the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences,UNKP-184-BME-209 New National Excellence Program of the Ministry of Human Capacities,OTKA 112699,128543 and 131586This research was supported by the European Union and the Hungarian State,co financed by the European Regional Development Fund in the framework of the GINOP-2.3.4-15-2016-00004 project,aimed to promote the cooperation between the higher education and the industryThe research reported in this paper has been supported by the National Research,Development and Innovation Fund(TUDFO/51757/2019-1TM,Thematic Excellence Program).
文摘The separation of non-ideal mixtures using distillation can be an extremely complex process and there continues to be a need to further improve these techniques.A new method which combines extractive heterogeneous-azeotropic distillation(EHAD)and hydrophilic pervapora-tion(HPV)for the separation of non-ideal termary mixtures is demonstrated.This improved distillation method combines the benefits of heterogeneous-azeotropic and extractive distillations in one column but no added materials are needed as is usually the case with pervaporation.The separation of water-methanol-ethyl acetate and water-methanol-isopropyl acetate mixtures were investigated to demonstrate the accuracy of the combined EHAD/HPV technique.There is not currently an established treatment strategy for the separation of the second mixtures in the literature.These separation processes were rigorously modelled and optimized using a professional flowsheet.The objective functions were total cost and energy consumption and heat integration was also investigated.The verification of the process modelling was carried out using laboratory-scale measurements.Extractive heterogeneous-distillation combined with methanol dehydration was found to be more efficient than conventional distillation for the separation of these highly non-ideal mixtures.
基金Supported by Shenzhen Innovator Special Fund(GRCK2017081715551149)。
文摘GaN field-effect transistors(FET)have low conduction and switching losses in high-frequency(>MHz)resonant wireless power transfer systems.Nevertheless,such systems impose a unique stress on GaN FETs owing to their non-ideal voltage waveforms.In this work,we report the observed non-ideal behavior in a 6.78 MHz magnetic resonant wireless transfer system that employs class-D GaN power amplifiers.The non-ideal waveform phenomenon existing at the output of the power amplifier is explained.The study analyzes the causes of this phenomenon,including the coupling coefficient k of the coil,the DC input voltage of the amplifier,and the load on the receiver.Each parameter is simulated and analyzed using LTspice.The influence of the phenomenon on the on-state resistance of the GaN device is proved in an experimental measurement,and the cause of the phenomenon is explained.The study combines a theoretical simulation and an experimental test to discuss the effect of this phenomenon on GaN power devices and proposes the corresponding solutions,which include the limitation of voltage,current,and power of the system,thermal management,and other protection measures.
基金Supported by National Natural Science Foundation of China(11375100)Strategic Pioneer Program on Space Sciences,Chinese Academy of Sciences(XDA04060606-06)State Key Laboratory of Particle Detection and Electronics
文摘SCAs （Switched Capacitor Arrays） have a wide range of uses, especially in high energy physics, nuclear science and astrophysics experiments. This paper presents a method of using a MOS capacitor as a sampling capacitor to gain larger capacitance with small capacitor area in SCA design. It studies the non-ideal effects of the MOS capacitor and comes up with ways to reduce these adverse effects. A prototype SCA ASIC which uses a MOS capacitor to store the samples has been designed and tested to verify this method. The SCA integrates 32 channels and each has 64 cells and a readout amplifier. The stored voltage is converted to a pair of differential currents （~ 4 mA max） and multiplexed to the output. All the functionalities have been verified. The power consumption is less than 2 mW/ch. The INL of all the cells in one channel are better than 0.39%. The equivalent input noise of the SCA has been tested to be 2.2 mV with 625 kHz full-scale sine wave as input, sampling at 40 MSPS （Mega-samples per Second） and reading out at 5 MHz. The effective resolution is 8.8 bits considering 1 V dynamic range. The maximum sampling rate reaches up to 50 MSPS and readout rate of 15 MHz to keep noise smaller than 2.5 mV. The test results validate the feasibility of the MOS capacitor.
文摘基于无线和电力线通信(power line communication,PLC)的双模通信可以实现二者优势互补,被广泛用于智能计量和电力物联网中。针对正交频分复用(orthogonal frequency division multiplexing,OFDM)双模通信系统在新能源低时延业务接入等应用,提出了一种计及非理想信道估计的OFDM子载波分集组合和功率自适应分配算法。首先建立了以业务数据量、传输功率等为约束,以总时延最小化为目标的功率自适应优化分配模型;接着在分集分组的基础上,利用鲸鱼优化算法和阈值回收进行功率优化分配,实现算法复杂度和性能的折中。仿真实验结果表明,提出的算法在满足速率等约束条件下,减小传输平均时延和稳定性,为台区设备状态监测等实时业务数据采集提供更高的性能保障。
文摘Isobaric molar heat capacity affected by pressures for non-ideal gases is calculated theoretically at specified temperatures by means of gaseous equations of state,i.e.Redlish-Kwong(RK)Equation,SoaveRedlich-Kwong(SRK)Equation,Peng-Robinson(PR)Equation,Virial Equation,coupled with Romberg numeric integral via solving the key obstacle(δV/δT)_(p),and integral(δ^(2)V/δT^(2))_(p).As an example,methane's C_(p)is calculated at constant 300 K but 1 MPa&10 MPa.The calculation results show that less than 2%relative errors occur in comparison with literature values at any specified temperatures and pressures if no phase change survives at elevated pressure P_(2)and temperature T,or when specified temperatures are greater than critical temperatures in spite of elevated pressures.However,greater errors would be present if gases were considered to be ideal,or if temperatures are lower than critical temperatures at elevated pressures(>10 MPa),because C_(p)is the function of both temperature and pressure.In particular,elevated pressures have significant effect on C_(p).
