期刊文献+
共找到15篇文章
< 1 >
每页显示 20 50 100
Feasibility Study on Recovering Human-Occupied Vehicle with An Offshore Crane
1
作者 HAN Ming-yue XIE Peng +4 位作者 XIAN Hao-yi ZHONG Xin-xin CHEN Sheng-lin SUN Tie-rui SUN Feng-lei 《China Ocean Engineering》 SCIE EI CSCD 2024年第4期648-662,共15页
Launching and recovering human-occupied vehicles(HOVs)has always been a challenging problem.The current recovery process requires staff to manually complete the tethering task,which is inefficient and endangers the li... Launching and recovering human-occupied vehicles(HOVs)has always been a challenging problem.The current recovery process requires staff to manually complete the tethering task,which is inefficient and endangers the lives of staff.This paper suggests moving the recovery position from the surface to underwater at approximately half the wavelength of the water depth(30−50 m underwater),where the HOV experiences less environmental disturbance.An ROV equipped with a ultra-short baseline beacon(USBL)and a manipulator was used to complete the tethering operation.Additionally,a shackle customized to the shape of the manipulator’s gripper is fitted to the end of the cable to simplify the tethering process.To investigate the dynamic response of recovering the HOV using this suggested method,a comprehensive numerical model is developed in this research.The effects of wind,surface waves,ocean currents,and nonlinear interaction between the installation vessel and the HOV are quantitatively examined.The results show that the proposed recovery method can reduce the motion amplitude of the HOV and that the wave has the greatest influence on the dynamic response of the HOV during the recovery process.This model provides better insight into the proposed HOV recovery method and confirms the effectiveness of the heave compensation system.The proposed approach aims to enhance safety and operational efficiency by reducing direct human involvement in the recovery process and mitigating potential dangers.This finding holds particular significance,especially in environmentally sensitive areas,where reducing the impact on the surrounding ecosystem is crucial. 展开更多
关键词 human-occupied vehicle recovery dynamic response active heave compensation
下载PDF
Thermal Distortion Compensation for Improving Electrical Performance of Reflector Antennas 被引量:1
2
作者 Jiamei Kang Wei Wang +2 位作者 Shuo Zhang Shaofan Lian Hong Bao 《Open Journal of Applied Sciences》 2021年第4期523-540,共18页
Aiming at the problem of the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load. This paper presents a method to compensat... Aiming at the problem of the surface accuracy and electrical performance of the antenna in space environment are reduced due to thermal deformation caused by temperature load. This paper presents a method to compensate the thermally induced shape distortion of antenna reflector by actively adjusting actuators in order to improve the electrical performance. The adjustment of each actuator is related to the local deformation of the panel. Then, taking a space deployable antenna with a diameter of 5 meters as an example, the finite element model is established. According to the range of the temperature variation in space (<span style="white-space:nowrap;">&#8722;</span>180<span style="white-space:nowrap;">&#176;</span>C - 200<span style="white-space:nowrap;">&#176;</span>C), different temperature loads are applied to the antenna. The variation of electrical properties and surface accuracy is analyzed and the worst working condition is determined, and the antenna is compensated based on this condition. Then, four different electrical performance parameters are used as the optimization objectives, and the electromechanical coupling optimization model is established, and the PSO algorithm is used to optimize the actuators adjustments. The results show that the method can effectively improve the electrical performance of the deformed reflector antenna. 展开更多
关键词 Space Reflector Antenna Thermal Distortion active compensation Electrical Performance PSO
下载PDF
An active temperature compensated fiber Bragg grating vibration sensor for high-temperature application 被引量:2
3
作者 CHEN Bao-jie JIA Ping-gang +4 位作者 QIAN Jiang FENG Fei HONG Ying-ping LIU Wen-yi XIONG Ji-jun 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2020年第4期397-404,共8页
An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified b... An active temperature compensated fiber Bragg grating(FBG)vibration sensor with a constant section cantilever beam is proposed for the simultaneous measurement of temperature and vibration,and the sensor is verified by a temperature compensation feedback system.The high-temperature vibration sensor is composed of a quartz cantilever beam and a femtosecond Bragg grating.The feedback control demodulation system of active temperature compensation can adjust the laser wavelength to stabilize the grating offset point and realize simultaneous measurement of temperature and vibration.On this basis,the performance of the sensor is tested and analyzed within the range of 20-400℃by setting up a high-temperature vibration test system.The experimental results show that the sensitivity of the sensor is about 132.33 mV/g,and the nonlinearity is about 3.33%.The sensitivity between the laser wavelength and temperature is about 0.01307 nm/℃.In addition,the active temperature compensated fiber Bragg grating vibration sensor has the advantages of a simple structure,stable performance,easy demodulation and high sensitivity.Moreover,the sensor can achieve high temperature vibration signal monitoring and has good practical application value. 展开更多
关键词 fiber Bragg grating(FBG) vibration sensor active temperature compensation cantilever beam feedback control
下载PDF
Active Anomalous Transmission and Its Application in Compensating Waveform Distortions
4
作者 王春 陈雷 +5 位作者 乔闪 沈昱舟 朱安杰 叶德信 李长志 冉立新 《Chinese Physics Letters》 SCIE CAS CSCD 2017年第11期32-35,共4页
In theoty, engineered anomalous transmission in passive materials and waveguide devices can be used to compensate for wavetorm distortions. However, they suffer from inherent dissipation. Recently, active non-Foster e... In theoty, engineered anomalous transmission in passive materials and waveguide devices can be used to compensate for wavetorm distortions. However, they suffer from inherent dissipation. Recently, active non-Foster elements with imaginary immittance monotonically decreasing with frequency have shown important potentials in broadening bandwidths of electromagnetic devices. So far, they are implemented besed on negative impedance convertors (NICs) loaded with Foster devices. This makes them intrinsically one-port elements and thus cannot be used to compensate for distortions of signals. We construct a two-port network with a non-Foster transmission coefticient based on an unconventional use of NICs. Simulation and experiments show that it can compensate for extremely distorted signals. The proposed method can be used to broaden existing applications in different areas such as antennas, circuits and systems, and physical-layer signal processing. 展开更多
关键词 active Anomalous Transmission and Its Application in Compensating Waveform Distortions
原文传递
DOUBLE LOOP ACTIVE VIBRATION CONTROL OF PNEUMATIC ISOLATOR WITH TWO SEPARATE CHAMBERS
5
作者 YANG Qingjun LI Jun WANG Zuwen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2006年第4期610-613,共4页
A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation: ① The low frequency resonance... A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation: ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation (MFRC) are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions: one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously. 展开更多
关键词 Pneumatic isolator active vibration control Double-loop control Two separate chambers Mass flow rate compensation (MFRC)
下载PDF
Low-frequency characteristics extension for vibration sensors 被引量:2
6
作者 杨学山 高峰 候兴民 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2004年第1期139-146,共8页
Traditional magneto-electric vibration sensors and servo accelerometers have severe shortcomings when used to measure vibration where low frequency components predominate.A low frequency characteristic extension for v... Traditional magneto-electric vibration sensors and servo accelerometers have severe shortcomings when used to measure vibration where low frequency components predominate.A low frequency characteristic extension for velocity vibration sensors is presented in this paper.The passive circuit technology,active compensation technology and the closed- cycle pole compensation technology are used to extend the measurable range and to improve low frequency characteristics of sensors.Thses three types of low frequency velocity vibration sensors have been developed and widely adopted in China. 展开更多
关键词 vibration sensor low frequency characteristic extension passive circuit technology active compensation technology closed-cycle pole compensation
下载PDF
A low harmonic 12-pulse rectifier based on zigzag autotransformer by current injection at DC side 被引量:1
7
作者 LIU Jiongde CHEN Xiaoqiang +1 位作者 WANG Ying CHEN Tao 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第3期347-355,共9页
To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current i... To improve the harmonic suppression ability of multi-pulse rectifier,a 12-pulse rectifier based on zigzag autotransformer by DC side active compensation strategy is proposed.By controlling the small capacity current inverter to generate compensating currents and injecting the currents directly into the DC side of the system,the grid-side currents of the rectifier can be approximated to sine wave.Using zigzag autotransformer as phase-shifting transformer can block the zero sequence current components and reduce the equivalent capacity of the rectifying system.The study on harmonic distortion rate of grid-side currents with the variation of the load shows that the harmonic content of the compensated rectifier decreases significantly under various load conditions.The harmonic content of the grid-side currents of the proposed active injection rectifier is only 1.17%,and the equivalent capacity of the rectifier is calculated.The results show that the rectifier can not only suppress the harmonic currents,but also have a lower equivalent capacity. 展开更多
关键词 multi-pulse rectifier active compensation zigzag autotransformer equivalent capacity
下载PDF
Residual field suppression for magnetocardiography measurement inside a thin magnetically shielded room using bi-planar coil
8
作者 Kang Yang Hong-Wei Zhang +2 位作者 Qian-Nian Zhang Jun-Jun Zha Deng-Chao Huang 《Chinese Physics B》 SCIE EI CAS CSCD 2022年第7期229-234,共6页
For a magnetocardiography(MCG)system inside a magnetically shielded room(MSR),the residual field should be further suppressed to obtain high-quality MCG signals.In this paper,a compensation system has been developed b... For a magnetocardiography(MCG)system inside a magnetically shielded room(MSR),the residual field should be further suppressed to obtain high-quality MCG signals.In this paper,a compensation system has been developed based on the bi-planar coil and the proportional-integral-derivative(PID)controller.The bi-planar coil,derived from the target-field theory and the Tikhonov regularization method,is utilized to generate magnetic field with high uniformity in the predefined target region.And the PID controller is introduced to provide dynamic compensation current for the coil,according to the residual field change monitored by a reference SQUID magnetometer.The measurement results show that the noise suppression ratio(NSR)can reach above 20 dB in the low-frequency range from 0.1 Hz to 50 Hz.The DC component and the fluctuation of the residual field in time-domain can be respectively suppressed to 0 p T and 4 p T,indicating that this proposed compensation method is useful for the MCG measurement. 展开更多
关键词 SQUID MAGNETOCARDIOGRAPHY bi-planar coil active compensation
原文传递
Voltage sag compensation strategy for unified power quality conditioner with simultaneous reactive power injection 被引量:8
9
作者 Yunfei XU Xiangning XIAO +1 位作者 Yamin SUN Yunbo LONG 《Journal of Modern Power Systems and Clean Energy》 SCIE EI 2016年第1期113-122,共10页
Unified power quality conditioner(UPQC)holds the capability of solving power quality problems,especially shows good performance in the voltage sag compensation. In this paper, a compensation strategy based on simultan... Unified power quality conditioner(UPQC)holds the capability of solving power quality problems,especially shows good performance in the voltage sag compensation. In this paper, a compensation strategy based on simultaneous reactive power injection for UPQC(namely UPQC-SRI) is proposed to address the issue of voltage sag. The proposed UPQC-SRI determines the injection angle of compensation voltage with consideration of optimal configuration of UPQC current-carrying.Moreover, the compensation strategy also considers the current-carrying limit of UPQC, and then the zero active power injection region of UPQC-SRI(also called UPQCSRI region) is obtained. Under the conditions which exceed the UPQC-SRI region, the limit value of shunt current is determined by this proposed strategy. Finally, the proposed strategy and the corresponding algorithm are verified under the PSCAD/EMTDC platform. The result indicates the proposed UPQC-SRI strategy in this paper can provide more persistent voltage sag compensation than the previous strategies for the sensitive load. 展开更多
关键词 Unified power quality conditioner(UPQC) Voltage sag Simultaneous reactive power injection Zero active power injection compensation region
原文传递
ADRC based control for a class of input time delay systems 被引量:5
10
作者 Dongyang Zhang Xiaolan Yao +1 位作者 Qinghe Wu Zhuoyue Song 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第6期1210-1220,共11页
This paper is concerned with the control design and the theoretical analysis for a class of input time-delay systems with stable, critical stable or unstable poles. In order to overcome the time delay, a novel feed-fo... This paper is concerned with the control design and the theoretical analysis for a class of input time-delay systems with stable, critical stable or unstable poles. In order to overcome the time delay, a novel feed-forward compensation active disturbance rejection control(FFC-ADRC) approach is proposed. It combines advantages of the Smith predictor and the traditional active disturbance rejection control(ADRC). The tracking differentiator(TD) is designed to predict the control signal, which adds an anticipatory control to the control signal and allows a higher observer bandwidth to obtain better disturbance rejection. The modified extended state observer(ESO) is designed to estimate both system states and the total disturbances(internal disturbance, uncertainties and delayed disturbance). Then the Lyapunov theory and the theory of the input-output stability are applied to prove the asymptotic stability of the closed-loop control system. Finally, numerical simulations show the effectiveness and practicality of the proposed design. 展开更多
关键词 time-delay system feed-forward compensation active disturbance rejection control(FFC-ADRC) tracking differentiator(TD) Lyapunov theory bound-input-bound-output(BIBO) stability
下载PDF
Fiber-based quantum secure direct communication without active polarization compensation 被引量:3
11
作者 Xin Liu Di Luo +6 位作者 Guangshen Lin Zihao Chen Chunfeng Huang Shizhuo Li Chengxian Zhang Zhenrong Zhang Kejin Wei 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2022年第12期91-96,共6页
Quantum secure direct communication(QSDC)that allows people to directly transmit confidential information through insecure channels is an important branch of quantum communication.The widespread adoption of the QSDC d... Quantum secure direct communication(QSDC)that allows people to directly transmit confidential information through insecure channels is an important branch of quantum communication.The widespread adoption of the QSDC demands the development of simple and stable systems.However,most of the existent QSDC systems involve a complex self-alignment process at the initial stage and additional hardware to compensate environmental disturbance.In this study,we present a fiber-based QSDC system without active polarization compensation.Our system comprises a stable transmitter and a novel Sagnac-Mach-Zehnder interferometer for security detection.This robust system simplifies the self-alignment and is immune to environmental disturbance.The robustness of the system was theoretically and experimentally verified,and low bit error rates in a 12 min continuous operation with an active polarization scrambler were attained.In addition,we performed a proof-of-principle QSDC demonstration,and a secrecy capacity of 3.43 kbps over a 5 km fiber with a detection bit error rate of 0.85%±0.07%and a quantum bit error rate of 0.42%±0.05%were achieved.Experimental results confirm the viability of the proposed QSDC system for practical applications. 展开更多
关键词 quantum secure direct communication Sagnac-Mach-Zehnder interferometer without active polarization compensation
原文传递
Axonal remodeling in the corticospinal tract after stroke: how does rehabilitative training modulate it? 被引量:10
12
作者 Naohiko Okabe Kazuhiko Narita Osamu Miyamoto 《Neural Regeneration Research》 SCIE CAS CSCD 2017年第2期185-192,共8页
Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstru... Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals. 展开更多
关键词 stroke rehabilitative training axonal remodeling corticospinal tract motor map reorganization motor system neurotrophic factor functional compensation neural activity growth promoting signal growth inhibitory signal task-specific training
下载PDF
An Impedance-based Parameter Design Method for Active Damping of Load Converter Station in MTDC Distribution System 被引量:3
13
作者 Pengwei Chen Wenmeng Zhao +1 位作者 Xin Chen Wenwei Jiang 《Journal of Modern Power Systems and Clean Energy》 SCIE EI CSCD 2022年第5期1423-1436,共14页
To achieve the efficient application of impedance analysis in the stability assessment and enhancement of multiterminal DC distribution systems, this paper proposes the DCside reduced-order impedance models with power... To achieve the efficient application of impedance analysis in the stability assessment and enhancement of multiterminal DC distribution systems, this paper proposes the DCside reduced-order impedance models with power control and AC voltage control, respectively, by taking the load converter station as the object. By using the DC-side current as the feedforward state, the active compensator applied to the load converter station with two control modes is also derived as well as the corresponding reduced-order impedance models. Combined with the reduced-order impedance models, a method based on damping factor sensitivity is further proposed to design the parameters of the derived active compensators. The verification results in the frequency domain and time domain demonstrate the accuracy of the reduced-order impedance and the effectiveness of the proposed compensator parameter design method. 展开更多
关键词 Impedance modeling order reduction active compensator damping factor sensitivity
原文传递
Efficacy observation of Yiguanjian decoction combined adefovir Dipivoxil tablet in treating HBeAg negative chronic viral hepatitis B active compensated liver cirrhosis patients
14
作者 段淑红 《China Medical Abstracts(Internal Medicine)》 2016年第3期133-134,共2页
Objective To explore clinical efficacy of Yiguanjian Decoction(YD)combined Adefovir Dipivoxil Tablet(ADT)in treating HBe Ag negative chronic viral hepatitis B(CVHB)active compensated liver cirrhosis(LC)patients.Method... Objective To explore clinical efficacy of Yiguanjian Decoction(YD)combined Adefovir Dipivoxil Tablet(ADT)in treating HBe Ag negative chronic viral hepatitis B(CVHB)active compensated liver cirrhosis(LC)patients.Methods Totally 68 HBe Ag negative CVHB active compensated LC patients initially treated were assigned to the treatment group and the control group 展开更多
关键词 Ag ADT Efficacy observation of Yiguanjian decoction combined adefovir Dipivoxil tablet in treating HBeAg negative chronic viral hepatitis B active compensated liver cirrhosis patients HBV
原文传递
Anomalous Resistivity in Vanadium-Doped Semi-Insulating 4H-SiC Wafers
15
作者 Xianglong Yang Kun Yang +4 位作者 Yingxin Cui Yan Peng Xiufang Chen Xuejian Xie Xiaobo Hu 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2014年第6期1083-1087,共5页
The resistivities of vanadium-doped semi-insulating 4H-SiC wafers were measured by a contactless resistivity measurement system. Anomalous resistivity was found in semi-insulating 4H-SiC wafer. Raman spectra of semi-i... The resistivities of vanadium-doped semi-insulating 4H-SiC wafers were measured by a contactless resistivity measurement system. Anomalous resistivity was found in semi-insulating 4H-SiC wafer. Raman spectra of semi-insulating4H-SiC wafer indicated that the anomalous resistivity was caused by polytype inclusion. Based on the activation energies of different SiC polytypes calculated from resistivity versus temperature data measured by COREMA-VT, the resistivities in the vanadium-doped semi-insulating 4H-SiC wafer with 6H polytype inclusion were calculated. The calculated resistivities are quite consistent with the measured resistivities. Furthermore, the compensation mechanism for the formation of anomalous resistivity was proposed. 展开更多
关键词 SiC Anomalous resistivity Polytype inclusion Activation energy compensation mechanism
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部