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Chinese Physics B 2016年第8期25卷 437-442页

作者：刘玮李超孙兆阳赵宇吴世有方广有 Key Laboratory of Electromagnetic Radiation and Sensing Technology Institute of Electronics Chinese Academy of Sciences Beijing 100190 China Electric Power Research Institute of State Grid Beijing Electric Power Company Beijing 100161 China

In the terahertz（THz） band, the inherent shake of the human body may strongly impair the image quality of a beam scanning single frequency holography system for personnel screening. To realize accurate shake compensation in imaging processing, it is quite necessary to develop a high-precision measure system. However, in many cases, different parts of a human body may shake to different extents, resulting in greatly increasing the difficulty in conducting a reasonable measurement of body shake errors for image reconstruction. In this paper, a body shake error compensation algorithm based on the raw data is proposed. To analyze the effect of the body shake on the raw data, a model of echoed signal is rebuilt with considering both the beam scanning mode and the body shake. According to the rebuilt signal model, we derive the body shake error estimated method to compensate for the phase error. Simulation on the reconstruction of point targets with shake errors and proof-of-principle experiments on the human body in the 0.2-THz band are both performed to confirm the effectiveness of the body shake compensation algorithm proposed.

关键词： body shake compensation THz imaging single frequency holography beam scanning

compensation for time-delayed feedback bang-bang control of quasi-integrable Hamiltonian systems

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Science China(Technological Sciences) 2009年第3期52卷 688-697页

作者： LIU ZhongHua1 & ZHU WeiQiu2 1 Department of Civil Engineering, Xiamen University, Xiamen 361005, China 2 Department of Mechanics, State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University, Hangzhou 310027, China Department of Civil Engineering Xiamen University Xiamen China Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou China

The stochastic averaging method for quasi-integrable Hamiltonian systems with time-delayed feedback bang-bang control is first introduced. Then, two time delay compensation methods, namely the method of changing control force amplitude (CFA) and the method of changing control delay time (CDT), are proposed. The conditions applicable to each compensation method are discussed. Finally, an example is worked out in detail to illustrate the application and effectiveness of the proposed methods and the two compensation methods in combination.

关键词： time-delayed feedback control compensation method bang-bang control quasi-integrable Hamiltonian system

compensation EFFECT OF POLYIMIDE THIN FILMS ON NORMALLY WHITE TWISTED NEMATIC LIQUID CRYSTAL DISPLAYS

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Chinese Journal of Polymer Science 1997年第2期15卷 139-145页

作者：李宝忠何天白丁孟贤 Polymer Physics Laboratory Changchun Institute of Applied Chemistry Academia Sinica Changchun 130022

The disadvantages of Normally White Twisted Nematic Liquid Crystal Display (NW-TN-LCD) were discussed. The reason that the negative birefringent polyimide thin films were used to compensate NW-TN-LCD to decrease off-axis leakage, improve contrast ratios and enlarge viewing angles was explained in this paper. A certain polyimide thin film was taken as an example to show compensation effect on NW-TN-LCD.

关键词： polyimide thin films retardation compensation negative birefringence normally white twisted nematic liquid crystal display

compensation trends of the angulation of first molars:retrospective study of 1403 malocclusion cases

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International Journal of Oral Science 2014年第3期6卷 175-181页

作者： Hong Su Bing Han Sa Li Bin Na Wen Ma Tian-Min Xu Department of Orthodontics School and Hospital of Stomatology Peking University Department of Stomatology Shenzhen People’s Hospital Graduate from School and Hospital of Stomatology Peking University Arrail International Dental Clinic

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1 403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First,angulation of the upper first molar varied significantly with age and tipped most distally in cases aged,12 years and least distally in cases aged.16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability.

关键词： Angle classification angulation compensation first molar growth stages malocclusion sagittal skeletal patterns verticalskeletal patterns

compensation of Dead-Time Effect of Speed Sensorless Vector Control System

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Transactions of Tianjin University 2011年第5期17卷 351-355页

作者：夏超英张靖 School of Electrical Engineering and Automation Tianjin University

The key of speed sensorless vector control system lies in the accurate orientation of magnetic field. In some field-oriented algorithms, the integrator of observers and the dead-time effect bring in system errors during the estimation of field position. In this paper, a saturated feedback integrator is used, and the dead-time effect is compen- sated by current positive feedback. Experiments were carried out on the hardware platform of MCK2407, with chip TMS320LF2407 from TI Company. The results show that the prooosed method is simole and effective, and the accuracy of field position is improved.

关键词： induction motor speed sensorless vector control DSP compensation dead-time field orientation

An FFT-Based High SNR MWC Back-End Architecture with Analog Low-Pass Filter compensation

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Chinese Journal of Electronics 2020年第3期29卷 563-573页

作者： LIU Sujuan LIU Lei Beijing University of Technology

We study the impacts of non-ideal filters in Modulated wideband converter(MWC). An analog filter compensating method is presented. The limitations of the conventional back-end of the advanced MWC is analyzed and an improved back-end based on Fast Fourier transform(FFT) is proposed. By setting proper length of the digital signal processed each time, the proposed system increases the recovery Signal-to-noise ratio(SNR)and significantly reduces the computation loads. The compensating operation is accurate to each frequency point and the expanding operation is simplified to a splitting of the frequency points. Numerical simulations demonstrate our proposed system against the ideal MWC with different filters. The results indicate that the recovery SNR of over 70 decibel is achieved with almost only one-tenth the computation complexity of the conventional MWC backend.

关键词： Compressed sensing Modulated wideband converter Fast Fourier transform Non-ideal low-pass filters compensation

A 1.8-V 240-MHz 2.19-mW Four-Stage CMOS OTA with a Segmenting Frequency compensation Technique

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Chinese Journal of Electronics 2021年第5期30卷 853-860页

作者： LIANG Yuhua ZHENG Zirui LIU Shubin LI Dengquan DING Ruixue ZHU Zhangming School of Microelectronics Xidian University

A four-stage Operational transconductance amplifier(OTA) used in an infrared temperature sensor adopting the proposed Feed-forward Gm-stage and segmenting nested Miller compensation technique is presented. The purpose of the proposed segment compensation is primarily to make more amplifier stages concatenated. The circuit linked several transconductance stages to form a segment, and linked several segments to form a large multistage amplifier. For example, a twostage amplifier linked with a three-stage amplifier can realize a five-stage amplifier, two three-stage amplifiers linked can realize a six-stage amplifier. A four-stage amplifier in the form of 2+2(two stages and two stages)was used as an example to verify this compensation method. The proposed OTA is designed in the 180 nm complementary metal oxide semiconductor process. It consists of two parts which ensure the stability and improve the bandwidth performance. The first part is a feedforward transconductance stage, and the second part is the two-segment transconductance stages with the Miller compensation techniques employed within and between the two segments. Based on the small-signal model,stability analysis and theoretical derivation are performed in theory. On condition of a 2-pF load capacitance, a direct current gain of 109 dB and a gain-bandwidth of 240 MHz with a phase margin of 50° can be achieved. The proposed design consumes 2.19 mW in a 1.8-V supply voltage. The transient simulation indicates that the settling time of the output is 19 ns with the settling error being 1%, and the slew rate is 114 V/μs.

关键词： six-stage amplifier power 2.19 mW time 19.0 ns transient simulation four-stage Operational transconductance amplifier theoretical derivation compensation large multistage amplifier four-stage amplifier operational amplifiers five-stage amplifier small-signal model three-stage amplifier segmenting frequency compensation technique phase margin bandwidth performance complementary metal oxide semiconductor process CMOS analogue integrated circuits gain 109.0 dB feedforward amplifiers stability analysis two-stage amplifier capacitance 2 pF multistage amplifier two-segment transconductance stages integrated circuit design voltage 1.8 V four-stage CMOS OTA segmenting nested Miller compensation technique circuit stability bandwidth 240.0 MHz size 180.0 nm feedforward transconductance stage

An Improved Global Shutter Pixel with Extended Output Range and Linearity of compensation for CMOS Image Sensor

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Chinese Journal of Electronics 2021年第1期30卷 102-108页

作者： GUO Zhongjie YU Ningmei WU Longsheng School of Automation and Information Engineering Xi'an University of Technology Xi'an Microelectronic Technology Institute

An improved global shutter pixel structure with extended output range and linearity of compensation is proposed for CMOS image sensor. The potential switching of the sample and hold capacitor bottom plate outside the array is used to solve the problem of the serious swing limitation, which will attenuate the dynamic range of the image sensor. The non-linear problem caused by the substrate bias effect in the output process of the pixel source follower is solved by using the mirror FD point negative feedback self-establishment technology outside the array. The approach proposed in this paper has been verified in a global shutter CMOS image sensor with a scale of 1024×1024 pixels. The test results show that the output range is expanded from 0.95 V to 2 V, and the error introduced by the nonlinearity is sharply reduced from280 mV to 0.3 mV. Most importantly, the output range expansion circuit does not increase the additional pixel area and the power consumption. The power consumption of linearity correction circuit is only 23.1μW, accounting for less than 0.01% of the whole chip power consumption.

关键词： power 23.1 muW capacitors capacitance measurement global shutter CMOS image sensor compensation sample and hold circuits capacitive sensors pixel source follower voltage 0.95 V to 2.0 V improved global shutter pixel mirrors voltage 0.3 mV to 280.0 mV global shutter pixel structure output range expansion circuit nonlinear problem extended output range mirror FD point negative feedback self-establishment technology CMOS image sensors linearity correction circuit swing limitation substrate bias effect

Thermo-mechanical properties of bowl-shaped grinding wheel and machining error compensation for grinding indexable inserts

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Journal of Central South University 2015年第10期22卷 3830-3836页

作者：张祥雷姚斌陈彬强孙维方王萌萌罗琪 Department of Mechanical and Electrical Engineering School of Physics and Mechanical & Electrical EngineeringXiamen University

In order to meet the technical requirements of grinding the circumferential cutting edge of indexable inserts, thermo-mechanical properties of bowl-shaped grinding wheel in high speed grinding process and the influence of dimension variations of the grinding wheel on machining accuracy were investigated. Firstly, the variation trends of the dimension due to centrifugal force generated in different wheel speeds were studied and the effect of stress stiffening and spin softening was presented. Triangular heat flux distribution model was adopted to determine temperature distribution in grinding process. Temperature field cloud pictures were obtained by the finite element software. Then, dimension variation trends of wheel structure were acquired by considering the thermo-mechanical characteristic under combined action of centrifugal force and grinding heat at different speeds. A method of online dynamic monitoring and automatic compensation for dimension error of indexable insert was proposed. By experimental verification, the precision of the inserts satisfies the requirement of processing.

关键词： bowl-shaped grinding wheel thermo-mechanical properties indexable insert machining accuracy compensation

Cardinality compensation method based on information-weighted consensus filter using data clustering for multi-target tracking

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Chinese Journal of Aeronautics 2019年第9期32卷 2164-2173页

作者： Sunyoung KIM Changho KANG Changook PARK Department of Mechanical and Aerospace Engineering Seoul National UniversitySeoul 08826Republic of Korea BK21+Transformative Training Program for Creative Mechanical and Aerospace Engineers Seoul National UniversitySeoul 08826Republic of Korea Automation and Systems Research Institute Seoul 08826Republic of Korea Institute of Advanced Aerospace Technology Seoul 08826Republic of Korea

In this paper, a cardinality compensation method based on Information-weighted Consensus Filter(ICF) using data clustering is proposed in order to accurately estimate the cardinality of the Cardinalized Probability Hypothesis Density(CPHD) filter. Although the joint propagation of the intensity and the cardinality distribution in the CPHD filter process allows for more reliable estimation of the cardinality(target number) than the PHD filter, tracking loss may occur when noise and clutter are high in the measurements in a practical situation. For that reason, the cardinality compensation process is included in the CPHD filter, which is based on information fusion step using estimated cardinality obtained from the CPHD filter and measured cardinality obtained through data clustering. Here, the ICF is used for information fusion. To verify the performance of the proposed method, simulations were carried out and it was confirmed that the tracking performance of the multi-target was improved because the cardinality was estimated more accurately as compared to the existing techniques.

关键词： Cardinality compensation Cardinalized probability hypothesis density filter Data clustering Information-weighted consensus filter Multi-target tracking