• 조명전기설비학회논문지
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• 제21권5호
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• pp.82-89
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• 2007

여자제어 시스템의 AVR(Automatic Voltage Regulator) 장치는 발전기의 출력 전압을 일정하게 유지시키기 위하여, 여자기의 전압 또는 전류를 발전기 부하 전류 및 전압 변동에 따라 제어하는 역할을 수행한다. 이러한 AVR 장치의 응답성과 제어 특성은 발전기의 부하 변동 또는 과도 응답 상태에서의 출력 특성을 결정하게 된다. 본 논문에서는 고성능 전동기 제어 시스템에 널리 사용되고 있는 PWM 제어 시스템과 부하 변동에 강인하게 동작할 수 있는 과도 응답 보상기를 적용한 고성능 여자 시스템을 제안한다. 과도 응답 보상기는 발전기의 부하 전류 변동에 따라, 여자기의 제어신호를 PID 제어기의 출력에 더하여 빠른 속응성과 안정성을 가지도록 함으로써, 발전기의 출력 전압을 안정적으로 공급할 수 있도록 제어한다. 제안된 고성능 여자 시스템은 컴퓨터 시뮬레이션과 소형 발전기 시스템에 적용된 실험을 통하여 그 성능을 검증하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제10권2호
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• pp.156-164
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• 1986

In the case of boiling on high temperature wall, vapor film covers fully or parcially the surface. This phenomenon, film boiling or transition boiling, is very important in the surface heat treatment of metal, design of cryogenic heat exchanger and emergency cooling of nuclear reactor. Mainly supposed hydraulic-thermal accidents in nuclear reactor are LCCA (Loss of Coolant Accident) and PCM (Power-Cooling Mismatch). Recently, world-wide studies on reflooding of high temperature rod bundles after the occurrence of the above accidents focus attention on wall temperature history and required time in transient cooling process, wall superheat at rewet point, heat flux-wall superheat relationship beyond the transition boiling region, and two-phase flow state near the surface. It is considered that the further systematical study in this field will be in need in spite of the previous results in ref. (2), (3), (4). The paper is the study about the fast transient cooling process following the wall temperature excursion under the CHF (Critical Heat Flux) condition in a forced convective subcooled boiling system. The test section is a vertically arranged concentric annulus of 800 mm long and 10 mm hydraulic diameter. The inner tube, SUS 304 of 400 mm long, 8 mm I.D, and 7 mm O.D., is heated uniformly by the low voltage AC power. The wall temperature measurements were performed at the axial distance from the inlet of the heating tube, z=390 mm. 6 chromel- alumel thermocouples of 76 .mu.m were press fitted to the inner surface of the heating tube periphery. To investigate the heat transfer characteristics during the fast transient cooling process, the outer surface (fluid side) temperature and the surface heat flux are computed from the measured inner surface temperature history by means of a numerical method for inverse problems of transient heat conduction. Present cooling (boiling) curve is sufficiently compared with the previous results.

• 전자공학회논문지
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• 제51권12호
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• pp.197-203
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• 2014

뇌격전류가 정보통신설비의 접지시스템에 유입되었을 때 발생하는 과도전위상승에 대한 해석은 접지시스템을 효과적으로 설계하기 위해서 요구되는 사항 중에 하나이다. 접지시스템의 성능은 보통 접지시스템의 전기적 특성을 나타내는 접지임피던스와 과도전위상승으로 평가된다. 뇌격전류의 입사점에 따른 접지임피던스를 계산하는 방법을 제안하였다. 뇌격전류가 수평접지전극의 중앙에 입사되는 경우 델타갭소스 모델을 이용하여 접지임피던스를 계산하였다. 디바이 모델(Debye Model)을 이용하여 주파수의존적인 토양 파라미터를 적용할 수 있는 프로그램을 제안하였다. 그 이유는 접지시스템의 성능을 분석하는 상용프로그램은 주파수 의존적인 토양 파라미터 특성을 적용할 수 없기 때문이다. 동일한 조건에서의 시뮬레이션 결과의 신뢰성을 확인하기 위해서 실험을 수행하였다. 마지막으로, 토양 파라미터의 주파수의존성을 반영한 접지임피던스를 이용하여 뇌격전류파형에 따른 수평접지전극의 과도전위상승을 분석하였다.

• Journal of Radiation Protection and Research
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• 제32권2호
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• pp.71-78
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• 2007

본 연구에서는 원자력 발전소 주변 일시거주자의 방사선 비상시 소개와 관련된 사회행동 특성-특히 소개와 관련된 행동특성을 분석하는데 목적이 있다. 이를 위해 먼저, 이론적 검토 차원에서 비상사태시 소개의 의미와 유형, 그리고 소개를 시작하는데 소요되는 소개준비시간을 살펴보았다. 그리고 소개 대상 주민에 대한 행동특성을 울진, 월성 및 고리원전 방사선비상계획 구역 내에 체류하는 일시거주자를 대상으로 면접설문조사를 통해 실증 분석하였다. 연구의 주요 결과는 다음과 같다. 첫째, 방사선 비상시의 원활한 소개 및 안전 확보를 위하여 일시 거주자에게 소개 경보에 대한 사전 지식을 효율적으로 제공하기 위한 방안을 마련하는 것이 필요하다. 둘째, 방사선 비상시 일시거주자의 교육 훈련 방안을 마련하는 것이 필요하다. 셋째, 일시거주자가 자발적 소개를 하지 않으려는 이유와 배경을 파악하고, 대응 방안을 마련하는 것이 필요하다.

• 센서학회지
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• 제5권3호
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• pp.9-16
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• 1996

본 논문에서는 고전압 임펄스전압 발생장치의 조작에 의하여 발생하는 과도전압을 측정할 수 있는 용량성분 압기를 실현하였다. 전장센서를 이용한 과도전압측정계는 고속응답의 평판형 전장센서와 광대역 전압버퍼로 구성되었으며, 사용된 전압버퍼(LH0033)의 입력임피던스는 $10^{12}{\Omega}$ 정도로 대단히 높다. 단위계단 응답특성을 파악하기 위하여 새로운 교정방법을 제안하고, 설치조건에 따른 분압비 오차를 검토하였으며, 분압비 오차를 0.5% 이내로 하기 위한 최적설치조건을 제시하였다. 교정실험으로부터 과도전압측정계의 응답시간은 약 15.78 ns이었으며, 주파수대역은 6.37 Hz에서 27.3MHz이다. 따라서 본 측정계로 과도과전압은 물론 상용주파수전압도 신호의 일그러짐 없이 측정이 가능하였다.

• 대한한의학회지
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• 제24권2호
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• pp.66-80
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• 2003

Objectives : Recently, herbal acupuncture has been developed in the Korea since the earlier 1960' applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination the merit of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. Ramulus Uncariae Cum Uncis (釣鉤藤) has been claimed to possess sedative, anti-spasmodic actions, and treat childhood epilepsy in oriental medical preparation. Also, it has been stated that Ramulus Uncariae Cum Uncis was antioxidatvie effect and neuroprotection against glutamateinduced neuronal death. Methods : In this study, effects of Ramulus Uncariae Cum Uncis' herbal acupuncture on the $GV_{20}{\;}or{\;}LR_3$, named Baek-hue or Tae-chung, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group, respectively. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Especially, cFos expression was more increased at the herbal acupuncture on $GV_{20}{\;}than{\;}LR_3$, but FosB expression was more decreased in $LR_3$ group than $GV_{20}$ group. Also, pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($254.88{\pm}12{\;}pg/ml{\;}in{\;}GV_{20}$ group, $245.93{\pm}44.4{\;}pg/ml{\;}in{\;}LR_3$ group) and the cortex ($85.81{\pm}3.45{\;}pg/ml{\;}in{\;}GV_{20}$ group, $111.51{\pm}15.79{\;}pg/ml{\;}in{\;}LR_3$, group) compared to the hippocampus ($134.07{\pm}2.96{\;}pg/ml$) and the cortex ($61.16{\pm}4.11{\;}pg/ml$) in control group at 48 hrs after transient forebrain ischemia. Conclusion : These results suggest that pretreatment with Ramulus Uncariae Cum Uncis' herbal acupuncture on $GV_{20}{\;}or{\;}LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $GV_{20}{\;}or{\;}LR_3$ may be related to antioxidative effect and calcium channel block of Ramulus Uncariae Cum Uncis. Also, it could be mentioned there is specificity of acupoints treating ischemic injury through the difference between the herbal acupuncture of $GV_{20}{\;}and{\;}LR_3$.

• 대한한의학회지
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• 제24권2호
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• pp.81-93
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• 2003

Objectives : Recently, the new therapeutic tool, that is herbal acupuncture, has been developed and applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. The objective was to determine the effect of folium artemisiae argyi (艾葉) herbal acupuncture on the trasient forebrain ischemic injured rat. Methods : In this study, the effects of folium artemisiae argyi (艾葉) herbal acupuncture on the $LR_3$ named Taechung, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group. These features were observed in the retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($263.26{\pm}44.56{\;}pg/ml$ extracted by water, $275.35{\pm}51.47{\;}pg/ml$ extracted by moxa tar)and the cortex ($102.33{\pm}13.65{\;}pg/ml$ extracted by water, $109.54{\pm}9.37{\;}pg/ml$ extracted by moxa tar) compared to the hippocampus ($134.07{\pm}2.96{\;}pg/ml$) and the cortex ($61.16{\pm}4.11{\;}pg/ml$) in control group at 48 hrs after transient forebrain ischemia. Conclusions : These results suggest that pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $LR_3$ may be related to antioxidative function of folium artemisiae argyi.

• Korean Journal of Acupuncture
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• 제20권3호
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• pp.61-80
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• 2003

Objectives : Acupuncture and herbal medicine have been used to prevent and treat the cerebrovascular accident, such as a stroke, and many studies of acupuncture and moxibustion concerning to the stroke have been undertaken in the human and various animals. Recently, the new therapeutic tool, that is herbal acupuncture, has been developed since the 1950' and applied to various diseases including the cerebrovascular accident. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. Methods : In this study, effects of folium Artemisiae Argyi and moxa tar' herbal acupuncture on the $GV_{20}$, named Baek-Hue, on neuroprotection after the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohis- tochemistry and ELISA technique. Results : Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium Artemisiae Argyi or moxa tar' herbal acupuncture on $GV_{20}$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group, respectively. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium Artemisiae Argyi and moxa tar' herbal acupuncture on$GV_{20}$ significantly increased the expression of BDNF protein in the hippocampus and the cortex compared to control group at 48 hrs after transient forebrain ischemia, respectively. Conclusions : These results suggest that pretreatment with folium Artemisiae Argyi or moxa tar' herbal acupuncture on $GV_{20}$ has neuroprotective effect on transient forebrain ischemia and theherbal acupuncture on $GV_{20}$ may be related to antioxidative function.

• Korean Journal of Acupuncture
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• 제22권3호
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• pp.63-81
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• 2005

Herbal acupuncture has been used to prevent and treat the cerebrovascular accident, such as a stroke, and many studies of acupuncture and moxibustion concerning to the stroke have been undertaken in the human and various animals. The main characteristics of herbal acupuncture are a combination of acupuncture and herbal medicine. It was not well known the therapeutic effect and the mechanism of herbal acupuncture on transient forebrain ischemic injury, although it has been used frequently in clinics. In this study, neuroprotective effects of folium artemisiae argyi (艾葉)' herbal acupuncture on the $LR_3$ (Taechung) on the transient forebrain ischemia were investigated in Sprague-Dawely rats. Expressions of cFos, FosB and BDNF protein in the hippocampus and cortex were observed at 2 hrs and 48 hrs after transient forebrain ischemia by immunohistochemistry and ELISA technique. Expression of cFos protein was increased slightly in the hippocampus and cortex at 2 hrs after transient forebrain ischemia, but FosB protein was increased highly comparing to cFos protein. However, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased expression of cFos protein and significantly decreased expression of FosB protein compared to control group. These features were observed in the motor cortex and retrosplenial granular cortex as well as the hippocampus. Also, pretreatment with folium artemisiae argyi' herbal acupuncture on $LR_3$ significantly increased the expression of BDNF protein in the hippocampus ($263.26{\pm}44.56pg/ml$ extracted by water, $275.35{\pm}51.47pg/ml$ extracted by moxa tar)and the cortex ($102.33{\pm}13.65pg/ml$ extracted by water, $109.54{\pm}9.37pg/ml$ extracted by moxa tar) compared to the hippocampus $(134.07{\pm}2.96pg/ml)$ and the cortex $(61.16{\pm}4.11pg/ml)$ in control group at 48 hrs after transient forebrain ischemia. These results suggest that pretreatment with folium artemisiae argyi'herbal acupuncture on $LR_3$ has neuroprotective effect on transient forebrain ischemia and the herbal acupunture on $LR_3$ may be related to antioxidative function of folium artemisiae argyi.

• 조명전기설비학회논문지
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• 제13권3호
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• pp.101-108
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• 1999

본 논문은 임펄스전류에 대한 전력설비용 접지시스템의 과도응답특성에 대하여 기술하엿으며, 피뢰기 접지도선을 통하여 임펄스전류가 유입될 때, 공결점과 다른 접지도선에 유도되는 전위상승을 측정·분석하였다. 낙뢰서지에 의한 피뢰기의 동작을 모의하기 위하여 뇌임펄스전류를 인가하였으며, 본 실험에서 얻은 임펄스 응답특성의 실험결과는 다음과 같다. 접지전극에 유도되는 전위상승은 접지도선에 유도된 것과는 상당히 달았으며, 다른 독립접지전극에도 높은 전위유도가 발생하였다. 또한 임펄스전류에 의한 접지전극과 접지도선의 전위상승은 공결점의 위치에 따라 현저하게 변하였다. 근방공결한 경우 임펄스전류에 의한 공결점의 전위상승은 원방공결한 경우보다 낮게 나타났다. 피뢰기 접지도선의 전위상승은 근방공결한 경우가 원방공결항 것보다 높게 나타났다. 따라서 전위상승의 측면을 고려하면 근방공결하는 경우가 원방공결하는 것보다 효과적이고, 전력기기의 절연보호 측면에서는 원방공결하는 것이 보다 효과적임을 알았다.