Papers by Keyword: Impedance

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Authors: Jing Wang, Yong Zhang, Wen Li Guo, Tong Xiang Liang, Chang Sheng Deng, Jing Ming Xu
Abstract: La0.8Sr0.2FeO3 electrodes modified with nanoparticles of La0.8Sr0.2MnO3 (LSF/LSM) were prepared by infiltration method. LSM solution had good wettability on LSF surfaces and good electrochemical compatibility with LSF. The impedance of half-cells incorporating the electrodes was also examined. The deconvolution of the impedance spectrum indicated that the peak positions are changed after the LSF infiltration. The LSF/LSM electrode exhibited smaller polarization resistance than pure LSF electrode. Finally, a transform from asymmetry to symmetry appeared in the polarization curves of LSF/LSM electrode with the increase of temperature.
Authors: Qiang Liao, Tao Xu, Xiao Wei Li, Wei Dong Fan
Abstract: Acid value is one of the most important indexes in the detection of lubricating oil, the testing of which has been widely used in the corrosive and quality characterization of petroleum products. So far there is no widely adaptive method and instrument faced with acid value. By the use of impedance method, this paper has used AD5933 to establish a detection system on acid value and achieve detection without chemical and judgment. Convenient setting of parameters and processing and storage of data are realized by the virtual instrument technology. Based on serial communication and virtual I2C communication, timely two-way traffic of statistics is achieved. The checkout of the system is accomplished by the known impedance. According to GB on the test of acid value, through the preparation of oil samples, the feasibility and operability of the system are justified and the best test conditions are determined.
Authors: Hai Ye Qiao, Guang Ling Liang
Abstract: The use of TDR for a single test to analyze the state of communication lines is not accurate to fault location, It also can cause the confusion of fault type and other drawbacks. This paper proposes a analysis algorithm. It can comprehensive analysis TDR test circuit fault pattern and low-frequency circuit parameters of tested line, then it determines the type and position of faults. During a time period, It tests the circuit impedance with 5-element DC model, records the values of line impedance at different times. Combining Curves of the line impedance and TDR waveforms, It accurately determines fault type of the line through the TDR test and Position of fault. By the trying It can increase the accuracy of judging failure , reduce time of repairing.
Authors: Jium Ming Lin, Po Kuang Chang
Abstract: Conventional bio-probes are produced on a silicon substrate, they are not only fragile but unable to dispose according to the profile of human body in a large area manner, and thus the contact resistance between probe and skin may be increased. Besides, the signal processing devices are required to improve both S/N ratio and impedance matching problems. This paper proposes a novel remote human health monitor and an active RFID tag with replaceable non-frangible probes and thin-film-transistor (TFT) amplifiers. The probes are made of bio-degradable polymer (photo resist) and covered with bio-compatible TiN. In addition, we use two pieces of double sides conducting tapes to connect both TFT amplifiers and probe modules. Thus the probe module can be replaced easily by peeling the used probe module away from the double sides conducting tapes to supply a new one. Since the tag is a flexible plastic substrate, e, g. PT, PET and PI, so the probes are easier to deploy and conform to the human body profile. In addition, the signal can be amplified by the TFT amplifier nearby to improve both S/N ratio and impedance matching. Thus the human health conditions can be remotely monitored by measuring various acupuncture impedances via the active RFID tag. The active RFID monitoring range is 15m by using 2.45 GHz ISM band, the probe resistance and parasitic capacitance are as 2735 Ω and 60.7 pf, respectively. Since the typical human acupuncture point resistance is about 40-120KΩ, thus the proposed device and system can be applied.
Authors: Dong Jin Kim, Hyuk Chul Kwon, Seong Sik Hwang, Hong Pyo Kim
Abstract: Alloy 600(74wt% Ni, 15wt% Cr, 9wt% Fe) is used as a material for steam generator tubing in pressurized water reactors(PWR) due to its high corrosion resistance under a PWR environment whose primary side and secondary side are operated under 340oC, 150bar and 290oC, 50bar, respectively. However, in spite of its outstanding corrosion resistance, a stress corrosion cracking(SCC) which has been one of the most important degradation issues, has occurred occasionally owing to the severe high temperature and pressure condition of a PWR. It is expected that a SCC is deeply related to an electrochemical property of a passive film formed under a high temperature and pressure condition. Therefore an understanding of the basic electrochemical behaviors regarding an anodic dissolution and a passivation of the bare surface of metals and alloys provides important information about a SCC mechanism and control. In the present work, the passive oxide films on Alloy 600 were investigated as a function of the dissolved oxygen content and the pH by using a potentiodynamic polarization, electrochemical impedance spectroscopy(EIS) and a depth profiling by Auger electron spectroscopy(AES). For this purpose, 0.5M H3BO3, 0.5M Na2SO4 and 0.1M NaOH aqueous solutions with/without dissolved oxygen at 300oC were used as the test solutions. The resistance of an oxide formed in an aerated solution was smaller than that in a deaerated solution while the oxide film in the aerated solution was thicker than the oxide film in the deaerated solution.
Authors: Daiki Inoshita, Takeshi Iwamoto
Abstract: TRIP steel possesses excellent mechanical properties dominated by strain-induced martensitic transformation (SIMT). For automotive industries, if TRIP steel can be applied to shock absorption members, it can be considered that the weight of automobile can be reduced. However, the strain rate sensitivity of TRIP steels has not been fully understood because the strain rate sensitivity and the deformation mode dependency of SIMT are still unclear. Therefore, it is important to reveal these sensitivity and dependency for confirming a reliability of TRIP steel. Therefore, in this study, it is attempted to estimate the amount of produced martensite in TRIP steel by measuring the inductance of TRIP steel. The specimen made of TRIP steel is used as a core of a prototype coil manufactured in this study. Then, the compressive and tensile tests are conducted by using a material testing machine and a drop weight testing machine using the specimen inside the coil. The inductance of the coil with the deformed specimen are measured continuously during the tests.
Authors: Guang Cheng Long, Kun Lin Ma, You Jun Xie
Abstract: In order to understand microstructure characteristics and properties of reactive powder cementitious materials with low w/b, the A.C impedance test on reactive powder cementitious materials is carried out. The correlation between the impedance parameters, microstructure and properties of reactive powder cementitious materials is also analyzed. Results indicate that the impedance-frequency curve both for reactive powder mortar and ordinary cement mortar consists of vertical part in range of low frequency section and horizontal part within high frequency section. But the angle between vertical part and horizontal part of curve for reactive powder mortar is larger compared with ordinary specimen. There is a good linear relationship between the real part of impedance and angular frequency ω-1/2 for mortar when frequency is from 10Hz to 100Hz. And the slope φ of line increases with the additions of reactive powder and the lowering w/b. The mechanical strength and microstructure of reactive powder cementitious materials with low w/b can be expressed well by the A.C impedance characteristic parameters.
Authors: Hironori Yoshioka, Takashi Nakamura, Junji Senzaki, Atsushi Shimozato, Yasunori Tanaka, Hajime Okumura, Tsunenobu Kimoto
Abstract: We focused on the inability of the common high-low method to detect very fast interface states, and developed methods to evaluate such states (CψS method). We have investigated correlation between the interface state density (DIT) evaluated by the CψS method and MOSFET performance, and found that the DIT(CψS) was well reflected in MOSFET performance. Very fast interface states which are generated by nitridation restricted the improvement of subthreshold slope and field-effect mobility.
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