• 대한의용생체공학회:의공학회지
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• 제41권5호
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• pp.179-184
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• 2020

Purpose: The purpose of this study was to evaluate the effect according to the NEX, VENC, targeted cardiac phases on the velocity measurement of 4D phase-contrast MRI. Materials and Methods: The abdominal aortic phantom was made to experiment. The working fluid was mixed with water and glycerin to mimic the density and viscosity of human blood. The inlet velocity was Reynolds number 2000. The experimental conditions were NEX 1 and 4, VENC 102 cm/s and 200 cm/s, and 10 and 15 targeted cardiac phases, respectively. The average flow rate, average velocity, maximum velocity, and cross-section area were measured. Results: As a result of the case-by-case comparison, the error rate was less than 5%. There was no significant difference (p > 0.05). Conclusion: It is expected that this result will be useful for acquiring blood flow information in clinical practice.

• 열처리공학회지
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• 제1권1호
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• pp.8-12
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• 1988

This study has been carried out to evaluate gaseous nitrocarburizing treatment undertaken for pure iron at $570^{\circ}C$ in an atmosphere containing 50% endothermic gas, generated from natural gas, and 50% ammonia. The results obtained from the experiment are as follows ; 1) The microstructure of gaseous nitrocarburized pure iron consists of the compound layer on the surface and the diffusion zone beneath it. The compound layer progresses uniformly into ferrite with a thickness of $20{\mu}$ obtained after treating for 3 hours. 2) Chemical analysis has shown that the compound layer has a C/N ratio of 0.19 and that the average combined interstitial content of the compound layer is about 30 atomic percent, which is close to the lower limit of the ${\varepsilon}$-carbonitride phase field in Fe-C-N phase diagram. 3) X-ray diffraction analysis has revealed that the compound layer consists mainly of the c.p.h. phase, ${\varepsilon}-Fe_3$(C.N) and a small amount of $Fe_4N$ and traces of ferrite are also present in the compound layer. 4) The microhardness of the compound layer is about 600 V.H.N and shows a relatively sharp fall-off at the compound layer/diffusion zome interface. 5) The average actual degree of ammonia dissociation is calculated to be 27% for a gaseous nitrocarburizing treatment carried out at $570^{\circ}C$.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.172-179
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• 2004

Average Bi-directional flow tube was suggested to measure single and two phase flow rate. Its working principle is similar with Pilot tube, however, it makes it possible to eliminate the cooling system which is normally needed to prevent from flashing in the pressure impulse line of Pilot tube when it is used in the depressurization condition. The suggested instrumentation was tested in the air-water vertical test section which has 80mm inner diameter and 10m length. The flow tube was installed at 120 of L/D from inlet of test section. From the test, single air and water flow rate was measured successfully. For the emasurement of two phase flow rate, Chexal drift-flux correlation was used. In the test a new correlation of momentum exchange factor was suggested. The test result shows that the suggested instrumentation using the measured void fraction and Chexal drift-flux correlation can predict the mass flow rates within $10\%$ error of measured data.

• 전력전자학회논문지
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• 제6권1호
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• pp.27-33
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• 2001

본 연구에서는 독립형 TMS32OC31 DSP보드에 의해 전략분석 과정을 완전 소프트웨어화하고, 전압센서와 전류 센서를 시스템 내부에 탑재한 저전력용 3상 모터구동장치플 위한 전랙품질 분석시스템을 개발하였다. 평균전력이 론에 의해 전략품질을 분석하였고 분석 결과를 LCD화변에 의해서 실시간으로 출력하였다. 특히 개발된 시스템은 설치공간이 필요한 종전의 대전력용 전력분석장비와는 다르게, 상용 인버터에 곧바로 탑재 가능하도록 히여 설치 공간을 줄였고 또한 초보자도 사용하기 용이하게 하였다. 정상상태와 모터구동장치의 부하가 급변하는 과도상태에 서도 제안된 전력품질 분석시스템은 실시간으로 전력분석을 하였으며, 본 연구의 유용성을 엽증할 수 있었다.

• 한국재료학회지
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• 제9권6호
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• pp.589-594
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• 1999

The effect of $\beta$-heat treatment on th microstructure, mechanical properties and texture in the nuclear fuel cladding of Zircaloy-4 tubes was chosen at 1000, 1100 and 120$0^{\circ}C$, and the tubes were heat-treated by a high frequency vacuum induction furnace. Morphology of the second phase particles and $\alpha$-grain of as-received tubes were markedly changed by heat treatment. The average sizes of second phase particles of as-received and $\beta$-heat treated tubes were 0.1$\mu\textrm{m}$ and 0.076$\mu\textrm{m}$, respectively. However, the average sizes of second phase particles were not much changed in the $\beta$-heated temperatures. With increasing heat treatment temperatures, the 0.2% yield strength and the hoop strength were decreased because of changes in preferred orientation as will as $\alpha$-plate width. Heat treated Zircaloy-4 tubes exhibited texture changes but the preferred orientation of grains still remained.

• 정보과학회 논문지
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• 제42권9호
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• pp.1071-1077
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• 2015

본 논문은 PCM을 가상메모리 스왑 장치로 사용하는 시스템을 위한 새로운 페이지 교체 기법을 제안한다. 제안하는 기법은 메모리 내의 각 페이지에 대한 수정 정도를 고려해서 교체 대상 페이지를 선정하며 이를 통해 PCM에 발생시키는 쓰기량을 줄인다. 즉, 제안하는 기법은 페이지의 수정 정도를 서브페이지 단위로 관리하고 최근에 사용되지 않은 페이지 중 수정된 서브페이지의 수가 최소인 페이지를 교체한다. 트레이스를 이용한 재현 실험을 통해 제안한 기법이 기존 CLOCK 알고리즘 대비 평균 22.9% 최대 73.7%의 PCM 쓰기량을 절감함을 확인하였다. 또한 PCM의 수명과 에너지 소모율을 각각 평균 49.0%와 3.0% 개선함을 보였다.

• Journal of Korean Academy of Oral Health
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• 제42권4호
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• pp.109-117
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• 2018

Objectives: The purpose of this study was to evaluate the customized oral health promotion program for North Korean defectors (NKDs). Methods: Using a pre-survey comprising phases 1-5 of the PRECEDE-PROCEED model, a customized oral health promotion program was created. The participants, a total of 129 NKDs, were allocated to the experimental group (n=64; 43 females and 21 males) or the control group (n=65; 46 females and 19 males). After the interventions, phases 7 to 9 of the PRECEDE-PROCEED model were executed to determine the effect of the program. Results: The results for phase 7 revealed high satisfaction with the program, with an average of 2.89 out of 3 points. In phase 8, concerning the impact evaluation, it was found that oral health beliefs and oral health knowledge were improved, with statistically significance differences before and after the experiment. Phase 9, concerning the outcome evaluation, showed that there were statistically significant differences in the average within groups before and after education in oral health beliefs (OHB), O'Leary index scores, and CPI. In terms of the difference between the groups, there were statistically significant improvement in OHB, O'Leary index scores, and CPI after the education program. Conclusions: The oral health promotion program developed in this study has made a positive contribution to improve the oral health status of NKDs.

• 디지털산업정보학회논문지
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• 제19권2호
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• pp.11-25
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• 2023

With the increasing advancement of VLSI technology, health care system is also developing to serve the humanity with better care. Therefore, biomedical implantable devices are one of the amazing important invention of scientist to collect data from the body cell for the diagnosis of diseases without any pain. This Biomedical implantable transceiver circuit has several important issues. Oscillator is one of them. For the design flexibility and complete transistor-based architecture ring oscillator is favorite to the oscillator circuit designer. This paper represents the design and analysis of the a 9-stage CMOS ring oscillator using cadence virtuoso tool in 180nm technology. It is also designed to generate the carrier signal of 403.5MHz frequency. Ring oscillator comprises of odd number of stages with a feedback circuit forming a closed loop. This circuit was designed with 9-stages of delay inverter and simulated for various parameters such as delay, phase noise or jitter and power consumption. The average power consumption for this oscillator is 9.32㎼ and average phase noise is only -86 dBc/Hz with the source voltage of 0.8827V.

• 대한방사선치료학회지
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• 제26권1호
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• pp.69-76
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• 2014

목 적 : 외부 압박을 통해 전립선암 환자의 복강 내 압력을 안정화시켜 움직임을 감소하여 치료 간(interfraction)과 치료 중(intrafraction)에 변화를 측정하여 평가하고자 시행하였다. 대상 및 방법 : 10명의 전립선환자들은 전체 치료과정동안 MVCT 스캔을 통해 치료 전과 후에 걸쳐 환자 당 60개의 영상을 획득하였고 획득한 좌우방향(X), 상하방향(Y), 전후방향(Z), 회전방향(Roll)에 대한 Shift 값들을 이용하여 복부 압박 시 치료 간 치료준비 변화와 치료 중 표적 움직임의 상호 연관성을 분석하였다. 결 과 : 치료 간의 움직임 변화는 평균 좌우방향(X)에서 $0.65{\pm}2.32mm$, 상하방향(Y)에서 $1.41{\pm}4.83mm$, 전후방향(Z)에서 $0.73{\pm}0.52mm$, 회전방향(Roll)에서 $0.96{\pm}0.21^{\circ}$로 나타났다. 치료 중 움직임 변화는 평균 좌우방향(X)에서 $0.15{\pm}0.44mm$, 상하방향(Y)에서 $0.13{\pm}0.44mm$, 전후방향(Z)에서 $0.24{\pm}0.64mm$, 회전방향(Roll)에서 $0.1{\pm}0.9^{\circ}$로 나타났다. 결 론 : 전처치과정과 외부에서 복부압박을 통한 전복부의 움직임을 제한한다면 치료동안에 내부 장기와 환자의 움직임을 감소시켜 보다 적은 여유(margin)로 계획용 표적체적(PTV)을 생성할 수 있어서 정상조직의 부작용 증가 없이 더욱 이상적인 선량 체적을 얻을 수 있을 것으로 사료된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.275-279
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• 1998

The influence of $WO_3$ (0.5-4.0mol%) on the microstructural and electrical properties of ZnO varistors was investigated. The major part of a tungsten segregated to the nodal point. SEM, EDAX, and XRD analysis revealed that three phase, such as W-rich phase, Bi-rich phase, and spinel phase, coexist at the nodal point. The average grain size increased in the range of 15.5-29.9pm with increasing $WO_3$ content. This may be probably attributed to liquid phase formed by $WO_3$, $WO_3$ acted as promotion additive of grain growth. As $WO_3$ content increase, the varistor voltage greatly decreased in the range 186.82-35.87V/mm due to the increase of grain growth. The barrier height decreased in the range 1.93-0.42eV with increasing $WO_3$content.