液體 噴流의 安定 曲線에서의 臨界 레이놀즈 수의 豫測

황용하,임성빈 忠州大學校 2003 한국교통대학교 논문집 Vol.38 No.4

The first maximum point in the stability curve of liquid jet, ie, the critical point is associated with the critical Reynolds number. This critical Reynolds number should be predicted by simple means. In this work, the critical Reynolds number in the stability curve of liquid jet are predicted using the empirical correlations and the experimental data reported in the literatures. The critical Reynolds number was found to be a function of the Ohnesorge number, nozzle length-to-diameter ratio, ambient Weber number and nozzle inlet type. An empirical correlation for the critical Reynolds number as a function of the Ohnesorge number and nozzle length-to-diameter ratio is newly proposed here. Although an empirical correlation proposed in this work may not be universal because of excluiding the effects of ambient pressure and nozle inlet type, it has resonably agrees with the measured critical Reynolds number.

MR Spectroscopy로 진단한 Leigh 병 1례

황성욱,황태규,김용우 인제대학교 2006 仁濟醫學 Vol.27 No.-

Leigh syndrome is a progressive and degenerating central nerve system disease with symmetrically localized necrotic changes on the both gray and white matter, called subacute necrotizing encephalopathy. The causes of this disease have been revealed that defect of various enzymes (pyruvate dehydrogenase, repiratory complex Ⅰ, Ⅳ, Ⅴ, etc.)related to mitrochondrial carbonate metabolism and energy generating mechanisms. The clinical course is variable, and symptoms such as non-specific- seizure, respiratory failure, nystagmus, decreased muscle tone, developmental delay, vomiting and lethargy etc. appeared. And the diagnostic tool is not clear, so the diagnosis is difficult. Brain MRI and MR spectroscopy have been used to diagnose Leigh syndrome. We experienced 1 case of Leigh syndrome with typical MR, MR spectroscopic findings. MRI shows the lesions on midbrain, both basal ganglia, caudate nucleus, putamen, periaqueductal area, and periventricular white matter. MR spectroscopic findings showing high lactate peak were appropriate to Leigh disease. The patient is a 16-month-old girl with generalized weakness, and died within 1 month after first admission on our hospital. We report this case with typical MR spectroscopic findings.

강원도 삼척지역의 스멕타이트질 점토의 산상 및 특성

황진연,박성완,이상현,최수용 부산대학교 기초과학연구소 1995 부산대학교 기초과학연구소 연구논문집 Vol.15 No.-

The smectite-rich clays were found locally in Paleozoic calcareous sedimentary rocks in the Samcheok area. Their occurrences were investigated in detail, and the physico-chemical properties of the clays were also determined by X-ray diffraction, chemical analysis, thermal analysis and cation exchanging experiment. The smectitie clays occur as the fissure filling dyke developed in calcareous semimentary rock and as alteration products of instrusive rhyolite. Most of clays occur at the contact between the sedimentary rock and the rhyolite, and the alteration zone was observed only in rhyolite body close to the contact. Judging from their occurrences, it is believed that the smectite-rich clays in this area were formed by the hydrothemal alteration. The smectite clays from the area are mainly composed of Ca-montmorillinite, and associated with small quantities of quartz, opal-CT and feldspar. The montmorillinites from this area lower in Fe content, and higher in exchangeable Ca ion, compared to those of bentonite from the Yangnam-Yeongil area.

정신과 환자들의 의료서비스 이용에 관한 연구 : 경기도 연천 지역에서 In Yonchon Area of Kyunggi Province

황성혜,홍진표,권준수,우종인,김중술,조두영,이부영,조맹제,양병국,배재남 大韓神經精神醫學會 1996 신경정신의학 Vol.35 No.4

본 연구는 농촌지역 정신과 환자들의 의료서비스 이용 형태를 알아보고자 하여 행하여졌다. 경기도 연천군 주민중 1993년 1년간 지역 의료보험과 의료보호자료에서 정신과적 진단을 받은 사람들 1295명 중 209명을 대상으로 하였다. 연구자들이 제작한 반구조화된 면담도구를 사용하여 13명의 훈련된 면담자에 의해 증상을 처음 느낀 후 이용한 의료서비스를 차례대로 조사하였다. 결과는 다음과 같다. 정신증적 장애 환자들은 정신과 치료만을 받은 경우가 28.8%이며 처음 방문한 의료서비스는 정신과 45%, 일반의 28%, 약국 6%, 한방치료 5%, 요양원 6%, 기타 10%였다. 비정신증적 장애 환자들은 정신과를 한번이라도 이용한 경우는 32.1%였고 처음 방문한 의료서비스는 정신과 15%, 일반의59%,약국 17%, 한방치료8%, 기타1%였다. 진단에 따라서는, 정신분열병의 경우 64.5%가 처음에 정신과를 방문하였고 정동형 정신병의 경우는 20.8%에 불과했고 64.1%가 일반이나 약국을 처음에 방문하였다. 신경증적 장애(ICD-9 300)는 40.0%가 일반의만을 방문했다. 이상의 결과로 정신분열병 환자들은 대다수가 정신과 치료를 받는 것으로 나타났으나 정동형 정신병과 신경증적 장애는 다수가 일반의를 이용하는 것으로 나타났다. 지역사회 정신보건에서 일반의의 역할이 매우 중요하며 일반의에 대한 정신과 교육이 절실하고, 보다 전문적인 치료환경과 기술을 요하는 경우에는 정신과와의 연계 체계의 필요성도 요구된다. The purpose of this study was to investigate the pathways of health care seeking by the psychiatric patients at a well - defined rural area in Korea. Among 1,295 patients diagnosed to have mental disorders by ICD-9 in a year, all the psychotic patients(184 in number) and randomly selected 15% of nonpsychotic patients(162 in number) were selected as subjects of this study. Thirteen well - trained interviewers collected the data using semi-structurd inter-view instrument developed by the authors. Two hundred nine patients(60.4%) fully responded to the interviews. As for psychotic patients, 28.8% used only psychiatric services, and the first visits for help were psychiatrists, general practitioners, pharmacists, asylums and oriental herb medicine in the order of decreasing frequency. Only 32.1% of nonpsychotic patients used mental health specialties during the course of their illness, and their most common first visits for care were general practitioners(59%) followed by pharmacists(17%) and psychiatrists(15%). Majority(64%) of schizophrenic patient visited psychiatrist first, while 64.1% of affective psychosis patients visited general practitioners and pharmacists first. The forty percent of neurotic patients(ICD-9 300) visited general practitioners only for their health care.

수소화를 고려한 다결정 실리콘 박막 트랜지스터의 전기적 스트레스의 영향

황성수,황한욱,김용삼 명지대학교 대학원 1999 대학원논문집 Vol.3 No.-

We have investigated the effects of electrical stress on poly-Si TFTs with different hydrogen passivation conditions. The amounts of threshold voltage shift of hydrogen passivated poly-Si TFTs are much larger than those of as-fabricated devices both under the gate bias stressing and under the gate and drain bias stressing. Also, we have quantitatively analyzed the degradation phenomena using by analytical method we have suggested that the electron trapping in the gate dielectric is the dominant degradation mechanism in only gate bias stressed poly-Si TFT while the creation of defects in the channel region and poly-Si/SiO_2 interface is prevalent in gate and drain bias stressed device.

LDD 구조의 다결정 실리콘 박막 트랜지스터의 특성과 최적화

황한욱,황성수,김용상 명지대학교 대학원 1998 대학원논문집 Vol.2 No.-

We have fabricated a LDD structured polysilicon thin film transistor with low leakge current and be optimized LDD length has been obtained. The device performance is improved by hydrogen passivation process. The on/off current ratio of poly-Si TFT's with 0.5㎛ and 1.0㎛ LDD length is much higher than that of conventional structured device due to the decrease of leakage current. The optimized LDD length may be 0.5㎛ from the experimental data such as on/off current ratio, threshold voltage and hydrogenation effect.

누설전류 특성이 향상된 다결정 실리콘 박막 트랜지스터의 제작 및 특성에 관한 연구

황한욱,황성수,김동진,김용상 명지대학교 대학원 1997 대학원논문집 Vol.1 No.-

We have fabricated a LDD structured polysilicon thin film transistor with low leakge current and the optimized LDD length has been obtained. The device performance is improved by hydrogen passivation process. The on/off current ratio of poly-Si TFT's with 0.5 ㎛ and 1.0 ㎛ LDD length is much higher than that of conventional structured device due the decrease of leakage current. The optimized LDD length may be between 0.5 ㎛ and 1.0 ㎛ from the experimental data such as on/off current ratio, threshold voltage and hydrogenation effect.

LCC 기법을 이용한 신기술 에너지 절약기기의 적용 사례에 대한 경제성 평가 : 바닥 난방시스템을 중심으로 Focused on the Apartment Floor Heating System

황성수,김용혁,김용수 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2

The purpose of this study is to assess economic effect for the application of a new technology-based energy economizer Memo Valve from "I" company. The study has been performed using LCC technique for the economic assessment. Data for LCC analysis are collected from questionnaire survey and interview for the estimating and maintenance experts of apartment building. Based on the LCC analysis, the economic effect of Memo Valve has been predicted as follows: 9.5% of LCC saving, and 19 times return rate for the investment during 50 years of study period.

순차적으로 도우핑한 드레인을 가지는 다결정 실리콘 박막 트랜지스터의 특성 및 수소화 효과

황성수,김동진,황한욱,김용상 명지대학교 대학원 1997 대학원논문집 Vol.2 No.-

We have fabricated a novel gradually doped drain(GDD) structured poly-Si thin-film transistor. The GDD poly-Si TFTs reduce a fabrication process step, compared with the conventional LDD poly-Si TFT. without LDD implant by employing taper etched Si0_2 film instead of LDD implantation mask. The leakage current of GDD device is reduced two orders of magnitude from 21.52×10 exp (-9) A to 0.14×10 exp (-9) A in OFF state while keeping the ON current to be almost identical to that of the non-LDD poly-Si TFT's After 5 hours hydrogen passivation, the ON/OFF current ratio is increased by four times of magnitude, and the device characteristics, such as threshold voltage, subthreshold slope and leakage current, are improved remarkably.

상아질의 경도, 위치 및 잔존 상아질 후경이 상아질에 대한 부위별 미세 전단결합강도에 미치는 영향 : EFFECTS OF DENTINAL HARDNESS, POSITION, AND REMAINING DENTIN THICKNESS

황선성,임미경,이용근 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The aim of this study was to measure the regional mictr-shear bond strength of dentin bonding sgents to dentin, and to investigate the relationship between the micro-shear bond strength and two dentinal characteristics ; Vickers hardness and remaining dentin thickness. Twenty-four freshly extracted, noncarious human molars were selected for this study. The materials tested in this study consisted of two commercially available dentin bonding agents(MAC-BOND, ONE-STEP) and two restorative light-cured composite resins (AELITEFIL, Z100). The occlusal of side surface of tooth crown was sectioned to expose dentin, and the exposed surface was finally polished with # 600 sandpaper, Four groups of application methods were used combining the filling materials and the dentin bonding agents. The composite resin-attached tooth specimens were embeded in a cold cure acrylic resin. and were obtained from each tooth. The cut spectimens were divided into three groups depending on the position of the dentin bonding wurface. The micro-shear bond strength. remaining dentin thickness, and dentinal hardness were measured. Experimental results were then statestically analyzed with ANOVA, t-test, Scheffe test. and regression analysis. From this experiment, the following results were obtained : 1. In the case of occlusal surface bonding, the pooled micro-shear bond strength of ONSTAELIT group (16.62 MPa) was singificantly higher than that of MACB-AELIT group (9.91 MPa) (p<0.05). However, there was no significant difference in the mictr-shear bond strength depending on the centin positon (p>0.05). 2. In the case of side surface bonding of crown, the pooled micro-shear bond strength of four different bonding groups was not significantly different among each other (p>0.05). However, in three of the test groups (ONST-AELIT, MACB-Z100, ONST-Z100), the micro-sheer bond strength to the lower 1/3(Ⅲ) position was sugnuficantly lower than that to middle 1/3(Ⅱ) position of surface (p<0.05). 3. In the ONST-AELIT bonding group, the pooled micro-shear bond strength to the occlusal surface was significantly lower than that to the side surface of crown (p<0.05). 4. There was no significant correlation between the micro-shear bond strength and dentin hardness / remaining dentin thickness (p>0.05).