• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1061-1067
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• 2005

The resonant frequency modulation of $YBa_2Cu_3O_{7-x}$ meander lines has been investigated as functions of optical pulse energy and temperature by using a network analyzer. The frequency-domain measurements are performed by controlling both the resonant frequency and the frequency width. The meander lines, configured in a microstrip geometry, are illuminated by optical pulses from an actively mode-locked Nd:YAG laser. The variation of the resonant frequency shows a quadratic dependence on the reduced optical pulse energy $P/P_c$, where $P_c$ is defined as the critical optical pulse energy at which resonance signal has disappeared. As for the dependence on temperature, the results are in good agreement with the previously reported data.

• 연구논문집
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• 통권29호
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• pp.17-27
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• 1999

The experimental results of the 17K inertance tube pulse tube cryocooler for cooling cryosensors are presented in this paper. In prototype experiments, linear compressor is driven by linear motor, and inertance tubes are inserted between one liter reservoir and pulse tube. Design of the inertance tube pulse tube cryo-cooler is conducted by ARCOPTR program of NASA Ames Research Center. To find optimal conditions of inertance tube pulse tube cryocooler, no load temperature and refrigeration capacity according to the variations of inertance tube volume, reservoir volume and charging pressure are measured. and the cool down and load characteristics at the particular conditions are presented. As the representative results, no load temperature of the cold end is 52.7K and refrigeration capacity is 5W at 72K..

• 전기전자학회논문지
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• 제23권2호
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• pp.681-686
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• 2019

본 논문은 동일 크기의 인버터 체인을 가진 지연 버퍼를 사용한 펄스 수축방식에 기반된 CMOS 온도 센서를 제안한다. 온도 센서는 2 개의 서로 다른 온도 지연 라인을 가진 온도에 비례하여 펄스를 생성하는 온도-펄스 변환기( TPC)와 공정 변화에 민감하지 않도록 동일 크기를 가진 인버터 체인을 사용하여 펄스를 수축하여 디지털 값으로 변환하는 시간-디지털 변환기(TDC)로 구성된다. 칩은 공급 전압이 3.3 V인 $0.35{\mu}m$ CMOS 공정을 이용하여 $0.49{\mu}m{\times}0.23{\mu}m$의 면적으로 구현되었다. 측정 결과 $0^{\circ}C{\sim}100^{\circ}C$의 온도 센서 범위에 분해능은 9-비트 데이터에서 $0.24^{\circ}C/bit$를 가진다.

• 한국초전도ㆍ저온공학회논문지
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• 제6권2호
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• pp.40-45
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• 2004

The experimental results of the G-M (Gifford-McMahon) type pulse tube refrigerators are presented in this paper. The pulse tube refrigerator, which has no moving parts at its cold section, is attractive in obtaining higher reliability, simpler construction, and lower vibration than any other small refrigerators. The objectives of this study are to develop the design technology of the G-M type pulse tube refrigerator and acquire its application methods for replacing G-M cryocooler. As a preliminary test, the refrigeration performances of the basic, orifice, and double inlet pulse tube refrigerators were investigated. The lowest temperature obtained in the one-stage pulse tube refrigerator was 34.4K and the refrigeration capacity at the optimum operation condition was 23W at 80K. And the lowest temperature of the second stage cold head in the two-stage pulse tube refrigerators was 18.3K and the refrigeration capacities at optimum condition were 0.45W at 20K and 20W at 80K, respectively. Finally, the lowest temperature obtained in the three-stage pulse tube refrigerator was 29.8K and the refrigeration capacity at the optimum operation condition was 1.3W for 40K and 5W for 70K.

• 한국초전도ㆍ저온공학회논문지
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• 제9권2호
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• pp.35-38
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• 2007

A single-stage and two-stage pulse tube refrigerators have been designed for cryopump application. The different diameters of pulse tube and regenerator have been investigated at single-stage pulse tube refrigerator(PTR). Experiments have been performed on single-stage PTR to reach minimum temperature with optimum valve opening at a few frequencies. And the two-stage pulse tube refrigerators have been assembled with tested single-stage pulse tube and tested. When orifice turn is opened to 9 and double inlet is opened to 3 at a single-stage, the lowest temperature of 33.7 K is achieved. The cooling capacity at single-stage is 38 W at temperature of 80 K. A two-stage pulse tube refrigerator has 16.3K at the second stage and 59.7K at the first stage. The cooling capacity achieved is 16.5 W at 80 K, the first stage and 0.6 W at 20 K, the second stage. Some details on the design of pulse tube refrigerator and the experimental apparatus are given.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.186-187
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• 2007

In this work, a temperature stable PWM(Pulse width modulation) circuit is proposed. The designed PWM circuit has a temperature dependent current source and a temperature independent voltage to compensate electrical characteristics with operating temperature. The variation of driving current is from about 4% to -6% in the temperature range $0^{\circ}C\;to\;70^{\circ}C$ compared to the current at the room temperature. The variation of bandgap voltage reference is from about 1.3% to -0.2% with temperature when the supply voltage is 3.3 volts. From simulation results, the variation of output pulse width is less than from 0.86% to -0.38% in the temperature range $0^{\circ}C\;to\;70^{\circ}C$.

• The Korean Journal of Ecology
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• 제20권6호
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• pp.423-438
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• 1997

The structure and variation of the mating call in Rana nigromaculata was studied in a population at Da-rak, Chong-won, Chung-buk (36$\circ$ 37' latitude, 127$\circ$ 21' longitude) in Korea. The mating call consists of 3 to 8 pulse groups divided by clear silent intervals. Each pulse group is also composed of fine pulses. Temperature and body size affect the temporal and spectral characteristics of the mating call. Pulse, pulse group repetition rate and dominant frequency rise with increasing temperature, whereas pulse grouprepetition rate and dominant frequency decrease with increasing body size. A playback experiment was designed to establish the effect of a potential intruder on male calling. During the stimulus periods, resident males markedly decreased the pulse repetition rate, and icreased the rate of pulse groups, dominant frequency, and the number of call groups. This results indicate that this species responds in a graded fashion when interacting with other individuals.

• 대한한의진단학회지
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• 제12권1호
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• pp.103-130
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• 2008

Background: For standardizing of Han-Yeol [寒熱], which is a kind of diagnosis method in oriental medicine, it is necessary to investigate into relationship of symptoms and signs representative of Han-Yeol [寒熱] to the biofunctional medical signals; thermal temperature by Thermography, Pulse-Respiration Ratio and so on. By correlation analysis of these data items acquired from patients, it could be provides the fundamental data for standardizing of Han-Yeol [寒熱]. Objectives: We performed this study to check the characteristics of thermal temperature with Han-Yeol [寒熱] statue by pulse-respiration ratio. Methods: We selected nine regions around acupoints including Yin dang[印堂], Sugu[水溝, GV26], Ch'ondol[天突, CV22], Chonjung[CV17], Chung-wan[中脘, CV12], Chonchu[天樞 S25], No-gung[勞官, P8], and calculated based on the utility of R.O.I.(Region of Integer) by IR-2000 these points temperature from 68 subjects. In practicing pulse-respiration ratio over 4.0 means the statues of Yeol [熱], pulse-respiration ratio below 4.0 means the statues of Han [寒]. To optimum conditions thermal temperature, which are not effected by internal and external variables, we studied preceding research. The results shows that optimal time period is 20minutes after undressed and the optimal region is the region around acupoints including Sugu [水溝, GV26]. Based on a preceding research results, we analyzed these data by Paired T-test between GV26 Region and 8-Thermography Regions and two-way repeated ANOVA with thermography$({\Delta}T)$ and Han-Yeol [寒熱] statue by pulse-respiration ratio. Results: 1. In applying of two-way repeated ANOVA with thermography$({\Delta}T)$ and Han-Yeol [寒熱] statue by pulse-respiration ratio, Sugu [水溝穴, GV26] - [印堂穴, HN1], Sugu 水溝, GV26] - Chonjung[CV17], Sugu [水溝, GV26] -Chung-wan[中脘, CV12]had significant differences. 2. In applying of Paired T-test between Sugu [水溝穴, GV26] Region and 8- Thermography Regions, there were significant differences except of Sugu [水溝穴, GV26] -Chondolp[天突, CV22]. 3. In the difference of Sugu [水溝, GV26] -Chung-wan[中脘, CV12], thermal temperature increases a lot in the statues of Yeol [熱], thermal temperature decreases a lot in the statues of Han [寒]. Conclusions: On the analysis of Thermography, we obtain the measurement conditions were considered the individual variations. And it is different that the thermal temperature change on Thermography according to Han-Yeol [寒熱] statue by pulse-respiration ratio.

• 한국대기환경학회지
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• 제19권1호
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• pp.25-31
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• 2003

Ceramic filter has been demonstrated as an attractive system to improve the thermal efficiency and to reduce the effluent pollutants. Removal of particulates from the hot gas stream is very important in air pollution control. In particular, the elimination of the particulate matters discharged from a gas turbine at high temperature can prevent the corrosion inside the IGCC. In this study, a Lab. scale test and numerical simulation were carried out to comprehend the relationship between pulse jet pressure and recovery of pressure drop and to characterize the reverse cleaning flow through a ceramic fil-ter element under high temperature and high pressure. When the pulse-jet pressures were 2, 3 and 4 kg/$ extrm{cm}^2$, the cleaning effect increase of about 10~30% by recovery of pressure drop caused by pulse pressure. Cleaning effect at 45$0^{\circ}C$ was greater than that at 55$0^{\circ}C$ or 650$^{\circ}$ for the same pulse pressure. According to the result of the present simulation, high pressure has been formed in terminal and central regions in our models and temperature distribution caused by pulse air is to be uniform comparatively on inner surface of filter.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1329-1334
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• 2004

The most compact and convenient pulse tube cryocooler for practical applications is the coaxial type. It can replace Stirling cryocooler without any change to the Dewar or the connection to the cooled devices. The experimental results of the coaxial inertance tube pulse tube cryocooler for cooling superconductor RF filter are presented in this paper. To find optimal conditions of inertance tube pulse tube cryocooler, no load temperature according to the variations of inertance tube volume, reservoir volume are measured, and the cool down characteristics at the particular conditions are presented. In case of the coaxial type inertance tube pulse tube refrigerator, cool down time is the lowest in the inertance tube diameter of 1.3 mm and inertance tube length of 1900 mm and lowest temperature is 112K. This results are not satisfactory for practical applications. So, We propose vacuum insulation between regenerator and pulse tube in the Stirling type coaxial pulse tube cryocooler. Stirling type coaxial pulse tube cryocooler with the vacuum insulation between regenerator and pulse tube was designed and manufactured by KIMM(Korea Institute of Machinery and Materials). The optimal conditions will be tested for Stirling type coaxial pulse tube cryocooler with the vacuum insulation between regenerator and pulse tube.