• 대한기계학회논문집B
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• 제25권9호
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• pp.1201-1208
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• 2001

Variable temperature anemometer(VTA) has greater sensitivity than a conventional constant temperature anemometer(CTA). In order to design a reliable VTA system, however, an elaborate photoconductive cell stabilizing circuit which plays a key role in setting wire-overheat ratio should be firstly developed. In this study, a stabilizing circuit which adopts proportional-integral analog controller was proposed and thoroughly tested for its accuracy and reproducibility. In contrast to the available circuit suggested by Takagi, the present circuit has characteristic that the resistance of a photoconductive cell increases with the increase of input voltage, which makes the current circuit very suitable for the design of VTA. Finally, VTA adopting stabilizing circuit was made and the enhanced sensitivity of the VTA was validated experimentally by comparing the calibration curves of VTA and CTA.

• 한국군사과학기술학회지
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• 제19권4호
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• pp.435-442
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• 2016

For inertial navigation systems, initial information such as position, velocity and attitude is required for navigation. Self-alignment is the process to determine initial attitude on stationary condition using inertial measurements such as accelerations and angular rates. The accuracy of self-alignment is determined by inertial sensor error. As soon as an inertial navigation system is powered on, the temperature of accelerometer rises rapidly until temperature stabilization. It causes acceleration error which is called temperature stabilizing error of accelerometer. Therefore, temperature stabilizing error degrades the alignment accuracy and also increases alignment time. This paper suggests a method to calculate azimuthal attitude using curve fitting of horizontal control angular rate in fixed-gain self-alignment. It is verified by simulation and experiment that the accuracy is improved and the alignment time is reduced using the proposed method under existence of the temperature stabilizing error.

• 설비공학논문집
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• 제3권5호
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• pp.365-375
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• 1991

Confined natural convection due to lateral temperature difference in rectangular enclosures was studied numerically and experimentally for the insulated and the constant temperature enclosures. In the case of insulated enclosure, the flow pattern and heat transfer modes are rather simple depending mainly upon Rayleigh number. In the case of isothermal enclosure, however, the phenomena of flow and heat transfer are somewhat complex and interesting due to the stable thermal gradients and various circumstances resulted from four wall temperature conditions. As a dimensionless variable, to describe properly the flow and heat transfer phenomena in the isothermal enclosure, temperature difference ratio ${\Delta}T_v/{\Delta}T_H$ is newly introduced and this parameter seems to be appropriate in the analysis of results on the effect of stabilizing thermal gradient.

• 대한기계학회논문집B
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• 제25권9호
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• pp.1202-1202
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• 2001

• 오토저널
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• 제5권2호
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• pp.31-40
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• 1983

A study was made of the effect of cold working and stabilizing temperature on the fatigue properties of Aluminum alloy 5083. The amount of cold working ranged from 14% to 35% and stabilizing temperature was 120.deg. C-160.deg. C. Rotary bending fatigue test was carried out, and it was found that 1) E specimen that had been cold worked by the cold reduction of 35% and stabilized at 160.deg. C for 2 hours was showed the most excellent fatigue limit and endurance ratio and, 2) By the results of the between crack propagation behavior and stress intensity factor, E specimen was showed the better resistance to fatigue crack growth than others.

• 전자공학회논문지B
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• 제33B권3호
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• pp.47-55
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• 1996

An optical transmitter, which is a key component of the optical transmission system, converts the electrical signal to optical signal and consists of a high-speed current-pulse driver for laser diode and low-speed feedback loops that stabilize optical power against aging, power supply voltage fluctuations, and ambient temperature changes. In this paper, the power-stabilizing part, which forms the bulk of the optical transmitter circuitry was designed in integrted circuits. Operational amplifiers and reference voltage generation circuits, which were identified as key building blocks for the power-stabilizing feedback loops, were designed and were subsequently verified through HSPICE simulations. The designed operational amplifier consists of a two-stage folded cascode amplifier and class AB output stage, whereas the reference voltage is obtained by bandgap reference circuits. Finally the power-stabilizing circuitry was laid out based on 3\mu$m CMOS design rules for fabrication.

• 한국항공우주학회지
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• 제39권8호
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• pp.796-803
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• 2011

정지 상태에서 관성항법장치를 구성하는 가속도계 및 자이로 측정치를 이용하여 초기 자세를 구하는 것을 초기정렬 혹은 자가정렬이라 한다. 초기정렬의 정밀도는 관성항법장치에 탑재되는 관성센서의 성능에 의하여 결정되며 수평축 자세는 수평축 가속도계, 수직축 자세는 E축 자이로 성능에 의해 결정된다. 그러므로 관성센서에서 발생된 불확실한 오차는 초기정렬의 정밀도를 저하시키는 주요원인이 된다. 논 논문에서는 관성센서의 불확실한 오차 중에서 관성항법장치에 전원이 인가되어 온도가 안정화 되는 상태에서의 관성센서 오차가 초기정렬 성능에 어떠한 영향을 미치는 가를 이론적으로 분석하고 시뮬레이션을 통하여 검증한 결과를 제시한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.365-366
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• 2009

This study researched into the manufacture of current-limit module of using YBCO coated conductor. Regarding over-current of exceeding the critical current, the quench characteristics were researched according to the stabilizing layer through tendency in resistance, which is generated in conductor, by applying over-current to YBCO coated conductors, which have stabilizing layer. YBCO coated conductors, which were used in experiment, include one kind such as the conductor, which used stainless as the stabilizing layer. The critical current is 70 A. And, the critical temperature is with 90 K. First of all, the quench generation was researched under over-current of exceeding the critical current by using this YBCO coated conductors. The tendency of a rise in the detected voltage according to the applied current was measured. And, the tendency of a rise in resistance through voltage-current curve was measured. As a result, the point of time in thermal quench of conductor, which has stainless as the stabilizing layer, could be confirmed to be fast.

• Journal of Welding and Joining
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• 제33권4호
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• pp.30-36
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• 2015

Austenite stainless steel(SA213-TP347H) has widely been used for the superheater & reheater tube in USC(ultra-supercritica) coal boiler because of its high creep rupture strength and anti-oxidation. But recently, the short-term failures have happened frequently in heat affected zone for only 4,000~15,000hours of service. Many investigations have been conducted to understand the failure mechanism. The root cause of failure was comfirmed to "strain induce participation hardening crack" or "reheat cracking". This mechanism often occurred due to weld residual stress and precipitation of the Cr, Nb carbides in the stabilized stainless steel such as TP347H. This paper presents an analysis of failure tube and effect of the sample tubes that conducting stabilizing heat treatment in site after 11,380hours & 16,961hours of service. Visual inspection was performed. In addition, microscopic characteristics was identified by O.M, SEM, and hardness test was carried out to find out the heat treatment effects. Failures seem to happen because of being not conducted stabilizing heat treatment in site. And another cause is inadequate weld parameter such as pass, ampere, voltage, inter-pass temperature. Thus, this paper has the purpose to describe that how to prevent similar failures in those weld-joints.

• 한국식품영양학회지
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• 제14권4호
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• pp.300-304
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• 2001

The oxidative stability of salmon mince to which milk protein concentrate(MPC) added was investigated. Salmon mince was stored at 4$\^{C}$ for 21 days, at -18$\^{C}$ for 20 days and at -18$\^{C}$ for 20 days after cooking in an electric omen. At each storage point, peroxide values(POV) were determined. Salmon mince with 4% MPC increased greater oxidative stability than control (without MPC). Sensory evaluation for measuring the oxidative stability of salmon mince was accomplished. Sensory scares of salmon mince with 4% MPC were higher than those of control. The results indicate that MPC could be useful for oxidative stability, as stabilizing protein ingredient of salmon mince.