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Terahertz Direct Detection Characteristics of a Superconducting NbN Bolometer

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Chinese Physics Letters 2011年第1期28卷 50-53页

作者： REN Yuan MIAO Wei YAO Qi-Jun ZHANG Wen SHI Sheng-Cai Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 Graduate School of the Chinese Academy of Sciences Beijing 100049

We report the terahertz direct detection characteristics of a spiral antenna coupled NbN superconducting hot- electron bolometer （HEB） at a bath temperature of 4.2K. Thermal conductance determined from resistance transition curves with different bias currents is found to be 3 × 10 7 W/K. The device shows a read-out circuit limited noise equivalent power （NEP） of 4.5 × 10-12 W/Hz/2 at 4.2 K with a home-made transimpedance amplifier operating at room temperature.

关键词： Superconductivity instrumentation and measurement

Velocity measurement Based on Laser Doppler Effect

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Chinese Physics Letters 2010年第12期27卷 89-91页

作者：张艳艳霍玉晶何淑芳巩轲 Department of Electronic Engineering Tsinghua University Beijing 100084

A novel method for velocity measurement is presented. In this scheme, a parallel-linear-polarization dual- frequency laser is incident on the target and senses the target velocity with both the frequencies, which can increase the maximum measurable velocity significantly. The theoretical analysis and verification experiment of the novel method are presented, which show that high-velocity measurement can be achieved with high precision using this method.

关键词： instrumentation and measurement Optics, quantum optics and lasers

Nuclear Magnetic Resonance measurements of Original Water Saturation and Mobile Water Saturation in Low Permeability Sandstone Gas

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Chinese Physics Letters 2010年第12期27卷 217-218页

作者：高树生叶礼友熊伟郭和坤胡志明 Researeh Institute of Petroleum Exploration and Development-Langfang Langfang 065007 School of Energy Resources China University of Ceosciences Beijing 100083 Institute of Porous Flow and Fluid Mechanics Chinese Academy of Sciences Langfang 065007

We use nuclear magnetic resonance （NMR） and centrifugation to measure the original water saturation and mobile water saturation of cores from the Xujiahe low permeability sandstone gas reservoir, and compare the NMR results with the corresponding field data. It is shown that the NMR water saturation after 300psi centrifugation effectively represents the original water saturation measured by weighing fresh cores. There is a good correlation between mobile water saturation and the water production performance of the corresponding gas wells. The critical mobile water saturation whether reservoir produces water of the Xujiahe low permeability sandstone gas is 6%. The higher the mobile water saturation, the greater the water production rate of gas well. This indicates that well＇s water production performance can be forecasted by mobile water saturation of cores.

关键词： instrumentation and measurement Plasma physics

Adaptive Synchronization of an Array of Time-Varying Coupled Delayed Neural Networks

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Chinese Physics Letters 2010年第3期27卷 60-63页

作者：王健安刘贺平 School of Information Engineering University of Science and Technology Beijing Beijing 100083

Synchronization in an array of time-varying coupled delayed neural networks is investigated. We assume that the entries of time-varying coupling configuration matrix and inner-coupling matrix of the model are all bounded. By combining linear feedback with an adaptive control approach, some simple controllers are proposed to ensure the states of such coupled networks globally asymptotically synchronize to a desired synchronous solution. Simulation results are provided to demonstrate the effectiveness of the proposed approach.

关键词： instrumentation and measurement

Correlation of Photosensitization and Binding Mode of Methylene Blue and DNA

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Chinese Physics Letters 2011年第1期28卷 115-118页

作者： LIU Tao ZHANG Feng CHEN Ping TANG Guo-Qing LIN Lie Key Laboratory of Optoelectronic Information Science and Technology (Ministry of Education) Institute of Modern Optics Nankai University Tianjin 300071

Binding of methylene blue （MB） and DNA, photosensitization of MB in DNA, and correlation of photosensiti- zation and binding mode are studied at different concentration ratios of DNA and MB. The absorption spectra indicate that the electrostatic binding is the main mode at low γ ratios （γ≤ 2）, while at high γ ratios （γ 〉 2） the intercalative binding is dominated. Mudies on dynamics of photosensitization formation of singlet oxygen （102） for MB in DNA are carried out by using＂ time-resolved technology. There are no obvious changes of the singlet oxygen lifetime and the triplet state MB molecule （MB3＋＊） lifetime at low ratios, they are about 4 μs and 1 μs, respectively. However, we could not obtain the 1 O2 lifetime and MB3＋＊ lifetime due to the great decrease of 1 O2 phosphorescence signals at high ratios. These results show that the photosensitization and binding mode of MB in DNA possess high correlation. When MB binds with DNA by electrostatic interaction, type-lI photosen- sitization of MB plays a major role in photodynamic effect, the damage of DNA probably could be ascribed to 1 O2. However, at high ratios, binding mode between MB and DNA turns to intercalative binding, which greatly weakens the type-Ⅱ photosensitization process. Charge transfer between MB and DNA possibly becomes the main damage mechanism.

关键词： instrumentation and measurement Medical physics Biological physics

High-Quality Continuous-Wave Imaging with a 2.53 THz Optical Pumped Terahertz Laser and a Pyroelectric Detector

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Chinese Physics Letters 2010年第12期27卷 96-98页

作者：邴丕彬姚建铨徐德刚徐小燕李忠洋 The Institute of Laser and Optoelectronies College of Precision Instruments and Opto-Electronics Engineering Tianjin University Tianjin 300072 Key Laboratory of Optoeleetronics Information and Technical Science (Ministry of Education) Tianjin University Tianjin 300072

A cw terahertz （THz） transmission imaging system is demonstrated and a high-quality THz image can be obtained using a pyroelectric detector. The factors that affect the imaging quality, such as the THz wavelength, spot size on the sample surface, step length of the motor, and frequency of the chopper, are theoretically and experimentally investigated. The experimental results show that the maximum resolution of the THz image can reach 0.4mm with the THz wavelength of 118.8μm, the spot size of 1.8mm and the step length of 0.25mm.

关键词： instrumentation and measurement Optics, quantum optics and lasers

Fabrication of Dry Electrode for Recording Bio-potentials

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Chinese Physics Letters 2011年第1期28卷 47-49页

作者： WANG Yu GUO Kai PEI Wei-Hua GUI Qiang LI Xiao-Qian CHEN Hong-Da YANG Jian-Hong Institute of Microelectronics School of Physical Science and Technology Lanzhou University Lanzhou 730000 State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083

Development of minimally invasive dry electrodes for recording biopotentials is presented. The detailed fabrication process is outlined. A dry electrode is formed by a number of microneedles. The lengths of the microneedles are about 150μm and the diameters are about 50μm. The tips of the microneedles are sharp enough to penetrate into the skin. The silver/silver chloride is grown on microneedle arrays and demonstrates good character. The electrocardiogram shows that the dry electrode is suitable for recording biopotentials.

关键词： instrumentation and measurement Medical physics Biological physics

A Combined Alignment Method for Strapdown Inertial Navigation System on Stationary Base

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Journal of Harbin Institute of Technology(New Series) 2020年第6期27卷 57-71页

作者： Shuai Chen Xinzhi Liu Qian Sun Ya Zhang School of Information and Control Engineering Liaoning Shihua UniversityFushun 113001LiaoningChina Department of Applied Mathematics University of WaterlooWaterloo N2L3G1Canada College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China School of Electrical Engineering&Automation Harbin Institute of TechnologyHarbin 150001China

Owing to the weak observability of the azimuth misalignment angle,alignment accuracy and time are always the contradictory issues in the initial alignment process of Strapdown Inertial Navigation System(SINS),which requires a compromise between *** this paper,a combined alignment mechanism is proposed to construct an observable and controllable system model,which can effectively achieve higher azimuth alignment accuracy during the fixed time ***,the Reduced Order Kalman Filter(ROKF)alignment algorithm was utilized to calculate the misalignment angles in parallel with the classical gyrocompass alignment ***,the misalignment angles calculated by the gyrocompass alignment method were used to formulate the augmented measurement model with zero velocity ***,the zero velocity model of the ROKF method was switched into the augmented measurement model when the azimuth misalignment angle of the gyrocompass alignment method was close to steady *** combined alignment method was analyzed reasonably by the observability and the mathematical *** comparison results of the numerical simulation and the experimental data test showed that the combined method had good performance in terms of estimation accuracy and consistency of the alignment results.

关键词： inertial navigation instrumentation and measurement gyroscopes accelerometers Kalman filter measurement errors