The paper reveals the relation between the linear AND-OR gate and the emitter function logic. With theoretic calculation and PSPICE simulation, the paper proves that the linear AND-OR gates can work at super-high-spee...The paper reveals the relation between the linear AND-OR gate and the emitter function logic. With theoretic calculation and PSPICE simulation, the paper proves that the linear AND-OR gates can work at super-high-speed and can be multi-cascaded. On the basis of analyzing the high-speed switch units which coordinate with linear AND-OR gates, two kinds of emitter coupled logic circuits are designed. The paper also discusses the design principles of super-high-speed digital circuits, and some examples of combinational and sequential circuits using linear AND-OR gate are given.展开更多
This paper deals with the vertical vibration, the horizontal translatory and flexural vibrations of plate gate with a flat bottom under the action of unstable submerged underflow. Based on a non linear resonant oscil...This paper deals with the vertical vibration, the horizontal translatory and flexural vibrations of plate gate with a flat bottom under the action of unstable submerged underflow. Based on a non linear resonant oscillator model by which the coupled excitation mechanism between the unstable vortices and gate motion can be simulated, the differential equations for the three types of gate vibrations are established. The parameters in the equations are determined by model experiments. Then, the steady state non linear responses of the three types of gate vibrations are calculated. The calculation results are in good agreement with the experimental data of gate vibrations with different reduced velocity and gate parameters by previous researchers.展开更多
Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors （SPDs） are used to herald the...Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors （SPDs） are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Bene~ network is shown in which only one SPD is used.展开更多
According to the study of super-resolution range-gated system, we proposed an improved system with linear plus detects. And a range function is derived by considering the shot effect noise and dark current noise. The ...According to the study of super-resolution range-gated system, we proposed an improved system with linear plus detects. And a range function is derived by considering the shot effect noise and dark current noise. The simulation shows that the improved system has a good range accuracy capability.展开更多
随着5G通信、毫米波雷达和卫星通信系统对高频大功率器件线性度要求的不断提升,传统AlGaN/GaN高电子迁移率晶体管(High Electron Mobility Transfer,HEMT)在功率放大器应用中面临的非线性失真问题日益凸显。本文针对高线性度氮化镓功率...随着5G通信、毫米波雷达和卫星通信系统对高频大功率器件线性度要求的不断提升,传统AlGaN/GaN高电子迁移率晶体管(High Electron Mobility Transfer,HEMT)在功率放大器应用中面临的非线性失真问题日益凸显。本文针对高线性度氮化镓功率放大器件的设计需求,基于Silvaco TCAD软件,系统研究了栅源/栅漏间距(Lgs/Lgd)、异质结势垒层Al组分分布以及栅下凹槽结构对GaN HEMT器件转移特性及线性度关键指标--栅压摆幅(Gate Voltage Swing,GVS)的影响规律。通过对比分析发现,减小栅源栅漏间距以及增大栅源栅漏Al组分能够有效提高器件的GVS。减小栅下Al组分可以改善器件GVS大小并使器件的阈值电压正漂,随后结合栅下凹槽使得器件的GVS提高了55.56%。本研究为高线性度GaN功率器件的结构优化提供了系统的设计方法和理论依据。展开更多
Piezoelectric resonators are widely used in frequency reference devices, mass sensors, resonant sensors(such as gyros and accelerometers), etc. Piezoelectric resonators usually work in a special resonant mode. Obtaini...Piezoelectric resonators are widely used in frequency reference devices, mass sensors, resonant sensors(such as gyros and accelerometers), etc. Piezoelectric resonators usually work in a special resonant mode. Obtaining working resonant mode with high quality is key to improve the performance of piezoelectric resonators. In this paper, the resonance characteristics of a rectangular lead zirconium titanate(PZT) piezoelectric resonator are studied. On the basis of the field-programmable gate array(FPGA) embedded system, direct digital synthesizer(DDS) and automatic gain controller(AGC) are used to generate the driving signals with precisely adjustable frequency and amplitude. The driving signals are used to excite the piezoelectric resonator to the working vibration mode. The influence of the connection of driving electrodes and voltage amplitude on the vibration of the resonator is studied. The quality factor and vibration linearity of the resonator are studied with various driving methods mentioned in this paper. The resonator reaches resonant mode at 330 kHz by different driving methods.The relationship between resonant amplitude and driving signal amplitude is linear. The quality factor reaches over 150 by different driving methods. The results provide a theoretical reference for the efficient excitation of the piezoelectric resonator.展开更多
Recently,speech enhancement methods based on Generative Adversarial Networks have achieved good performance in time-domain noisy signals.However,the training of Generative Adversarial Networks has such problems as con...Recently,speech enhancement methods based on Generative Adversarial Networks have achieved good performance in time-domain noisy signals.However,the training of Generative Adversarial Networks has such problems as convergence difficulty,model collapse,etc.In this work,an end-to-end speech enhancement model based on Wasserstein Generative Adversarial Networks is proposed,and some improvements have been made in order to get faster convergence speed and better generated speech quality.Specifically,in the generator coding part,each convolution layer adopts different convolution kernel sizes to conduct convolution operations for obtaining speech coding information from multiple scales;a gated linear unit is introduced to alleviate the vanishing gradient problem with the increase of network depth;the gradient penalty of the discriminator is replaced with spectral normalization to accelerate the convergence rate of themodel;a hybrid penalty termcomposed of L1 regularization and a scale-invariant signal-to-distortion ratio is introduced into the loss function of the generator to improve the quality of generated speech.The experimental results on both TIMIT corpus and Tibetan corpus show that the proposed model improves the speech quality significantly and accelerates the convergence speed of the model.展开更多
水质指标具有多元相关性、时序性和非线性的特点,为有效预测河流水质变化,针对水质数据存在缺失和异常的问题,提出基于灰色关联分析-门控循环单元(Grey Relational Analysis-Gated Recurrent Unit, GRA-GRU)的水质预测模型。以淮河流域...水质指标具有多元相关性、时序性和非线性的特点,为有效预测河流水质变化,针对水质数据存在缺失和异常的问题,提出基于灰色关联分析-门控循环单元(Grey Relational Analysis-Gated Recurrent Unit, GRA-GRU)的水质预测模型。以淮河流域水质数据为样本,使用线性插值修补缺失数据和剔除的异常数据。使用灰色关联分析计算不同水质指标间的相关性,选择高相关性的水质指标以确定输入变量,并使用门控循环单元(Gated Recurrent Unit, GRU)预测不同的水质指标。将GRA-GRU的预测结果与反向传播神经网络(Back Propagation Neural Network, BPNN)、循环神经网络(Recurrent Neural Network, RNN)、长短期记忆神经网络(Long Short Term Memory, LSTM)、GRU及灰色关联分析-长短期记忆神经网络(Grey Relational Analysis-Long Short Term Memory, GRA-LSTM)进行对比分析,结果显示GRA-GRU在不同水质指标预测上具有较好的适应性,可以有效降低预测误差。其中,与其他模型相比,GRA-GRU预测的化学需氧量在均方根误差上分别降低了3.617%、0.681%、0.478%、1.505%和0.471%。展开更多
基金Supported by the National Natural Science Foundation of China
文摘The paper reveals the relation between the linear AND-OR gate and the emitter function logic. With theoretic calculation and PSPICE simulation, the paper proves that the linear AND-OR gates can work at super-high-speed and can be multi-cascaded. On the basis of analyzing the high-speed switch units which coordinate with linear AND-OR gates, two kinds of emitter coupled logic circuits are designed. The paper also discusses the design principles of super-high-speed digital circuits, and some examples of combinational and sequential circuits using linear AND-OR gate are given.
文摘This paper deals with the vertical vibration, the horizontal translatory and flexural vibrations of plate gate with a flat bottom under the action of unstable submerged underflow. Based on a non linear resonant oscillator model by which the coupled excitation mechanism between the unstable vortices and gate motion can be simulated, the differential equations for the three types of gate vibrations are established. The parameters in the equations are determined by model experiments. Then, the steady state non linear responses of the three types of gate vibrations are calculated. The calculation results are in good agreement with the experimental data of gate vibrations with different reduced velocity and gate parameters by previous researchers.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61372076 and 61301171)the 111 Project(Grant No.B08038)the Fundamental Research Funds for the Central Universities,China(Grant Nos.K5051301059 and K5051201021)
文摘Linear optical quantum Fredkin gate can be applied to quantum computing and quantum multi-user communication networks. In the existing linear optical scheme, two single photon detectors （SPDs） are used to herald the success of the quantum Fredkin gate while they have no photon count. But analysis results show that for non-perfect SPD, the lower the detector efficiency, the higher the heralded success rate by this scheme is. We propose an improved linear optical quantum Fredkin gate by designing a new heralding scheme with an auxiliary qubit and only one SPD, in which the higher the detection efficiency of the heralding detector, the higher the success rate of the gate is. The new heralding scheme can also work efficiently under a non-ideal single photon source. Based on this quantum Fredkin gate, large-scale quantum switching networks can be built. As an example, a quantum Bene~ network is shown in which only one SPD is used.
文摘According to the study of super-resolution range-gated system, we proposed an improved system with linear plus detects. And a range function is derived by considering the shot effect noise and dark current noise. The simulation shows that the improved system has a good range accuracy capability.
文摘随着5G通信、毫米波雷达和卫星通信系统对高频大功率器件线性度要求的不断提升,传统AlGaN/GaN高电子迁移率晶体管(High Electron Mobility Transfer,HEMT)在功率放大器应用中面临的非线性失真问题日益凸显。本文针对高线性度氮化镓功率放大器件的设计需求,基于Silvaco TCAD软件,系统研究了栅源/栅漏间距(Lgs/Lgd)、异质结势垒层Al组分分布以及栅下凹槽结构对GaN HEMT器件转移特性及线性度关键指标--栅压摆幅(Gate Voltage Swing,GVS)的影响规律。通过对比分析发现,减小栅源栅漏间距以及增大栅源栅漏Al组分能够有效提高器件的GVS。减小栅下Al组分可以改善器件GVS大小并使器件的阈值电压正漂,随后结合栅下凹槽使得器件的GVS提高了55.56%。本研究为高线性度GaN功率器件的结构优化提供了系统的设计方法和理论依据。
文摘Piezoelectric resonators are widely used in frequency reference devices, mass sensors, resonant sensors(such as gyros and accelerometers), etc. Piezoelectric resonators usually work in a special resonant mode. Obtaining working resonant mode with high quality is key to improve the performance of piezoelectric resonators. In this paper, the resonance characteristics of a rectangular lead zirconium titanate(PZT) piezoelectric resonator are studied. On the basis of the field-programmable gate array(FPGA) embedded system, direct digital synthesizer(DDS) and automatic gain controller(AGC) are used to generate the driving signals with precisely adjustable frequency and amplitude. The driving signals are used to excite the piezoelectric resonator to the working vibration mode. The influence of the connection of driving electrodes and voltage amplitude on the vibration of the resonator is studied. The quality factor and vibration linearity of the resonator are studied with various driving methods mentioned in this paper. The resonator reaches resonant mode at 330 kHz by different driving methods.The relationship between resonant amplitude and driving signal amplitude is linear. The quality factor reaches over 150 by different driving methods. The results provide a theoretical reference for the efficient excitation of the piezoelectric resonator.
基金supported by the National Science Foundation under Grant No.62066039.
文摘Recently,speech enhancement methods based on Generative Adversarial Networks have achieved good performance in time-domain noisy signals.However,the training of Generative Adversarial Networks has such problems as convergence difficulty,model collapse,etc.In this work,an end-to-end speech enhancement model based on Wasserstein Generative Adversarial Networks is proposed,and some improvements have been made in order to get faster convergence speed and better generated speech quality.Specifically,in the generator coding part,each convolution layer adopts different convolution kernel sizes to conduct convolution operations for obtaining speech coding information from multiple scales;a gated linear unit is introduced to alleviate the vanishing gradient problem with the increase of network depth;the gradient penalty of the discriminator is replaced with spectral normalization to accelerate the convergence rate of themodel;a hybrid penalty termcomposed of L1 regularization and a scale-invariant signal-to-distortion ratio is introduced into the loss function of the generator to improve the quality of generated speech.The experimental results on both TIMIT corpus and Tibetan corpus show that the proposed model improves the speech quality significantly and accelerates the convergence speed of the model.
文摘水质指标具有多元相关性、时序性和非线性的特点,为有效预测河流水质变化,针对水质数据存在缺失和异常的问题,提出基于灰色关联分析-门控循环单元(Grey Relational Analysis-Gated Recurrent Unit, GRA-GRU)的水质预测模型。以淮河流域水质数据为样本,使用线性插值修补缺失数据和剔除的异常数据。使用灰色关联分析计算不同水质指标间的相关性,选择高相关性的水质指标以确定输入变量,并使用门控循环单元(Gated Recurrent Unit, GRU)预测不同的水质指标。将GRA-GRU的预测结果与反向传播神经网络(Back Propagation Neural Network, BPNN)、循环神经网络(Recurrent Neural Network, RNN)、长短期记忆神经网络(Long Short Term Memory, LSTM)、GRU及灰色关联分析-长短期记忆神经网络(Grey Relational Analysis-Long Short Term Memory, GRA-LSTM)进行对比分析,结果显示GRA-GRU在不同水质指标预测上具有较好的适应性,可以有效降低预测误差。其中,与其他模型相比,GRA-GRU预测的化学需氧量在均方根误差上分别降低了3.617%、0.681%、0.478%、1.505%和0.471%。
