생후 등줄쥐의 대뇌겉질 및 줄무늬체에서 NADPH-diaphorase 양성신경세포에 관한 연구

황승준,이종환,홍혜남,이흥식,허영범,조정식 대한해부학회 1999 Anatomy & Cell Biology Vol.32 No.1

대구 및 인근지역의 도로먼지에 함유된 미량원소성분의 함량분포

황윤정,황승만,최진수,김무식,백성옥 嶺南大學校 環境問題硏究所 1998 環境硏究 Vol.17 No.2

요약문 본 연구는 각종 먼지 가운데서도 독성이 가장 큰 것으로 알려진 도로먼지에 함유된 미량원소 성분이 조성 및 특성을 파악하기 위해 1992년 1월에서 10월가지 주거지역, 상업지역, 공업지역, 교외지역, 전원지역 등에 위치한 도로에서 시료를 채취하였으며 채취된 시료는 산으로 추출한후 ICP로 분석하였다 . 그 결과 토사 및 황사현상과 같은 자연발생원과 연관지을 수 있는 Al, Ca, Mg, Ti, Si, Na, K의 농도가 지역에 따라서는 전원지역과 교외지역에서, 그리고 도로포장 형태에 따라서는 비포장 도로에서 높게 나타난 반면에, 각종 연소 및 차량과 같은 인위적인 발생원과 관련이 있는 As, Cr, Mn, Zn, Pb, Cu, Ni는 공업지역 및 상업지역, 그리고 아스팔트에서 비교적 높게 검출되어 이러한 미량원소성문들의 농도분포는 지역에 따라, 그리고 도로포장 형태에 따라 특징적인 양상을 나타내는 것으로 조사되었다. 또한 As, Pb, Al 등의 일부 미량원소성분들의 농도는 계절에 따른 차이를 나타내었으며, 농축계수에 의한 평가결과 농축계수가 낮게 나타난 Na, Si, Ti, K, Al 등은 자연발생원에 의해 상당한 영향을 받는 반면에 As, Pb, Zn 등은 농축계수가 매우 높게 나타나 이들 성분의 경우에는 인위적인 발생원에 의한 기여도가 큰 것으로 평가되었다. Abstract This study was carried out to characterize the trace elements in street dust known to contain several toxic elements. Street dust was collected in residential, commercial, industrial, suburban and rural area of Taegu and on the vicinity of Taegu from January to October, 1992. Total amount of 16 trace elements in street dust were analyzed by ICP spectrophotometer. While the levels of As, Cr, Mn, Zn, Pb, Cu and Ni were higher in industral and commercial area than any other area by sites and the highest levels appeared on asphalt and cement street by street conditions. Also the concentrations of some trace elements originated mainly from soil (e.g. Al, Ca, Mg, Si, Na) were higher in rural and suburban area by sites and the highest levels appeared in unpaved street by street conditions. The concentrations of several trace elements such as Aa, Pb, Al appeared seasonal differences. The estimated enrichment factors (EF) for Na, Si, Ti, K and Al components showed with soil compositions appeared to have low values, while As, Pb and Zn components showed relatively higher values. These results imply that the latter constituents were likely to be affected by dry and wet depositions of atmospheric particles orginated from anthropogenic sources such as fuel combustion and refuge burning.

인버터 구동용 유도전동기 고정자 권선의 절연특성 연구

황돈하,김동희,이광식,정원영,김영훈,오승훈 영남대학교 공업기술연구소 1999 工業技術硏究所論文集 Vol.27 No.2

Inverters with high speed switching and advanced PWM techniques are widely used for variable speed applications. But some adverse effects on the stator winding insulation are reported due to excessive voltage stress, which results in the premature insulation breakdown. This is aggravated by the high switching speed of modem switching devices such as IGBT (Insulated Gate Bi-polar Transistor) with which the rate of rise in voltage (dv/dt) increases considerably. In this paper, the test results for evaluation on the stator winding insulation of 310V induction motors are presented. Also, the insulation characteristics are presented in order to analyze the insulation strength under high voltage due to high switching speed of IGBT PWM inverter. 26 induction motors of 6 types with different wires and insulation techniques are built and thoroughly tested. The maximum partial discharge (PD) magnitude (Qm) and the discharge inception voltage (DIV) are obtained by PD test. Under AC current test, the rate of change in AC current (ΔI) and the change in dissipation factor (Δtanδ) are measured. From the above test data, the effects due to different wires and insulation techniques on the insulation characteristics of low-voltage induction motors are compared and analyzed. The insulation technique to enhance the insulation strength is suggested from the test results.

두가지 혈류 유발방법에 의한 새로운 심폐소생술(이중 혈류 유발 심폐소생술)장치의 개발

황성오,김현,조준휘,오범진,임종천,최경훈,윤정한,이승환,김영식,이강현,이윤선 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: There have been many efforts to augment blood flow during cardiopulmonary resuscitation. These efforts have focused on maximizing the effect of cardiac pump or thoracic pump alone. However, considering that the heart is the biggest blood reservoir and increase of intrathoracic pressure can generate blood flow, simultaneous exploitation of both mechanisms may have synergistic effect. We hypothesized that simultaneous chest constriction in addition to sternal compression by standard CPR may have additive hemodynamic effects by preventing deformation of the chest and increase of intrathoracic pressure. Methods and results: we built a new mechanical device to perform compression and thoracic constriction simultaneously. The device consists of two main elements. Piston in the center is to depress the sternum. Strap is to constrict the thorax circumferentially. Strap is attached to both sides of the piston. When the piston is pushed down, it depresses the sternum and pulls on the thoracic strap. To determine strap width to produce optimal hemodynamic effect, we measured hemodynamic parameters with variable widths of strap in two dogs after induction of ventricular fibrillation. Result of the experiment showed that 10cm wide strap was determined to be most effective. We also determined optimal depth of compression to produce maximal hemodynamic effect with animal experiments using two dogs. Animal experiments showed that the highest aortic pressure could be generated when the stemum was depressed to 5 cm. Cardiopulmonary resusciation using a new device could generate higher systolic aortic pressure, coronary perfusion pressure and end-tidal carbon dioxide tension in comparison with standard cardiopulmonary resuscitation in a pilot animal study using two dogs. Conclusion: New cardiopulmonary resuscitation method using a mechanical device designed by us could perform sternal compression and simultaneous thoracic constriction, and generate better hemodynamic effects than standard cardiopulmonary resuscitation in pilot animal experiments.

서울 강서지역 1개 대학병원에서 성인 급성 신우신염의 원인균과 항생제 감수성

황병연,이재갑,박대원,이연주,김성범,엄중식,손장욱,정희진,김우주,김민자,박승철 대한감염학회 2003 감염과 화학요법 Vol.35 No.5

목적 : 3년간 서울시 강서지역의 1개 대학병원에서 입원치료를 받은 성인 급성 신우신염 환자를 대상으로 원인균과 항생제 감수성을 조사하고, 향후 급성 신우신염의 초기 경험적 치료 항생제를 제안하고자 하였다. 방법 : 1999년 1월부터 2001년 12월까지 3년간 고려대학교 의과대학 구로병원에 상부요로감염으로 내원한 16세 이상 환자 229명의 의무 기록을 검토를 통하여, 인구학적 특성, 원인균, 항생제 감수성, 초기 항생제 사용 양상과 입원기간을 조사하였다. 결과 : 연구에 포함된 229명을 118명의 단순 신우신염군과 111명의 복잡 신우신염군으로 구분 하였다. 단수 신우신염의 평균 발생 연령은 38.2세와 복잡 신우신염 56.1세로 복잡 신우신염 환자의 연령이 유의하게 높았다(P<0.001). 양군 모두에서 원인균 중 E. coli의 분리율이 가장 높았으며 항생제 감수성 결과 ampicillin, trimethoprim-sulfame-thoxazole에는 높은 내성률을 보였고, ciprofloxacin, gentamicin, cefotaxime에 대한 감수성은 비교적 높았으나 복잡 신우신염의 경우 단순 신우신염에 비하여 ciprofloxacin, gentamicin에 대한 감수성이 다소 낮은 것을 확인할 수 있었다. 평균 입원 기간, 항생제 투여 기간에 있어서도 복잡 신우신염군에서 유의하게 길었다. 결과 : 본 연구의 결과 서울의 강서 지역에서 대학병원급에 치료 의뢰되는 단순 급성 신우신염의 치료에 있어 1차 항생제로 3세대 cephalosporin, aminoglycoside, quinolone 중 한가지를 초기 경험적 치료제로 사용을 고려하여야 할 것으로 사료된다. Background : The purpose of this study is to recommend the initial therapeutic regimen for adult patients with acute pyelonephritis (APN) according to the changes of antimicrobial susceptibility patterns of causative microorganisms isolated from patients with APN. Methods : We reviewed medical charts of 229 APN patients, who had been treated at Korea University Guro Hospital from 1st of January. 1999 to 31st of December, 2001. We investigated the demographic data, clinical findings, durations of hospital treatment, antimicrobial susceptibility patterns of the causative microorganisms and initial antibiotic regimens in patients with APN. Results : In this study, 229 adult patients with APN were classified into simple APN patients (118 patients, 51.5%) and complicated APN patients (111 patients, 48.4%). Mean age of patients with simple APN was 38.2±14.1 years old and that of patients with complicated APN was 56.1±14.9 years old. Mean age of patients with complicated APN was significantly higher than that of simple APN patients (P<0.0001). Escherichia coli was the most common microorganism both in simple APN (96.7%) group and in complicated APN (90.6%) group. Antimicrobial susceptibility of E. coli was at the low level of ampicillin (31%/20%) and trimethoprim-sulfamethoxazole (42.6%/34.2%) in each group. In contrast, ciprofloxacin (11.5%/22.7%), gentamicin (16.4%/22%) and cefotaxime (0%/8.2%) resistance remained at relatively lower level. In comparison of simple APN with complicated APN, ciprofloxacin and gentamicin resistances were higher in complicted APN group. Average duration of hospitalization (5.9±2.3 days/8.2±4.6 days) and duration of antibiotic use (12.1±3.9 days/15.3±10.0 days) were significantly longer in complicated APN. Conclusions: The results of this study suggests that 3rd cephalosporin, aminoglycoside or quinolone antibiotic would considered as one of the initial therapeutic regimen for patients with simple APN in southwestern Seoul.

Butyl acetate-MEK 혼합용매를 이용한 초산분리에 관한 연구

장윤식,황승순,박동원 동아대학교 환경문제연구소 2000 硏究報告 Vol.23 No.1

We studied on the phase equilibria of quaternary liquid-liquid extraction system containing acetic acid-water-binary solvent at 25℃, MEK-butyl acetate were used as binary solvents. Binodal curve, tie-line, distribution and selectivity for each quaternary system have been determined in order to investigate the effect of using binary solvent in extracting acetic acid from aqueous solution. And these experimental tie-line data were also compared with the values predicted by WAC model. It was shown that UNIFAC model is capable of predicting the tie-line in these quaternary systems within an average RSDM of 3.76 mol%.

수출용 축양품종 가지의 염절임 공정의 최적화

남학식,김남우,황성희,윤광섭,신승렬 한국식품저장유통학회 ( 구 한국농산물저장유통학회 ) 2003 한국식품저장유통학회지 Vol.10 No.3

가지의 수출 경쟁력 향상을 위한 한 방안으로 수출용 가지품종인 축양품종을 염가공품으로 개발하기 위하여 염절임공정을 최적화하였다. 염절임 시간, 절임온도, 염농도를 독립변수로 하고 절임 후 수분함량, 염도, 표면과 내부의 색도 등을 종속변수로 하여, 중심합성계획법으로 실험을 설계하여 최적조건을 얻고자 하였다. 수립된 이차회귀모형으로 예측식을 수립할 수 있었으며 특히 수분함량이나 염도, 표면과 내부의 L과 b 값에 대하여 높은 적합도를 보여 최적조건을 수립하기 위한 제한 변수로 선정하였다. 염농도를 중심점(30%)에서 고정시켜서 얻은 절임시간과 온도는 각각 5.5~6.5일과 13-17℃였으며, 이때의 종속변수의 제한 요건으로는 수분함량 84%이하, 염도 14%이하 표면 L값 10-20, b값 0이하, 내부 L 값은 70-75, b 값이 16-18이었다. This study was conducted to the optimize salting process of eggplant for development new product and enhancement quality for export. Three variables by five level central composite design and response surface methodology were used to determine optimum conditions for salting time, temperature and salt concentration. Optimization of the process was conducted using the combination of the moisture content, salinity and color of surface and inside of salted eggplant. The regression polynomial model was suitable (P>0.05) by Lack-of-Fit analysis with highly significant. To optimize the process, based on surface response and contour plots, the individual contour plots of the response variables were superimposed. The optimum conditions for this process were 6 days and 15℃ at 30% concentration under the optimum of restricted variables as moisture content was below 84%, salinity was below 14%, L and b value of surface were 10 to 20 and below 0, L value and b value of inside were 70 to 75 and 16 to 18.

ZVS를 이용한 풀 브릿지 단일 전력단 고주파 공진 AC-DC 컨버터의 특성해석

남승식,황계호,오경섭,원재선,조규판,김동희 嶺南大學校 工業技術硏究所 2003 工業技術硏究所論文集 Vol.31 No.2

This paper proposes a single-stage high frequency resonant AC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter ingegrates a half bridge boost rectifier as power factor corrector(PFC) and half resonant converter into a single stage. The input stage of the half bridge boost converter is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. Therefore, high power factor is achieved naturally. The results of simulation using the Pspice have demonstrated the feasibility of the proposed AC-DC converter. The proposed converter will be able to be practically used as power supply.

등줄쥐의 대뇌겉질에 분포하는 NADPH-diaphorase와 Neuropeptide Y 양성반응신경세포에 관한 연구

허영범,황승준,조정식 대한해부학회 1997 Anatomy & Cell Biology Vol.30 No.1

순차적 크리깅기법을 이용한 미소혼합기의 최적화

박재용,유진식,황승민,임민규,오영규,김용대,한석영,맹주성 한국공작기계학회 2008 한국공작기계학회 추계학술대회논문집 Vol.2008 No.-

An active micro-mixer, which is composed of an oscillating micro-stirrer in the micro-channel to provide effective mixing was optimized. The effects of molecular diffusion and disturbance by the stirrer were considered with regard to two types of mixer models: the simple straight micro-channel and micro-channel with an oscillating stirrer. Two types of mixer models were studied by analyzing mixing behaviors such as their interaction after the stirrer. The mixing was calculated by Lattice Boltzmann methods using the D2Q9 model. In this study, the time-averaged mixing index formula was used to estimate the mixing performance of time-dependent flow. The mixing indices of the two models were compared. From the results, it was found that the mixer with an oscillating stirrer was much more enhanced' and stabilized. Therefore, an approximate optimization of an active micro-mixer with an oscillating stirrer was performed using Kriging method with OLHD (Optimal Latin Hypercube Design) in order to determine the optimal design variables. The design parameters were established as the frequency, the length and the angle of the stirrer. The optimal values were obtained as 1.5754, 0.803D and ±45°, respectively. It was found that the mixing index of the optimal design increased by 83.36% compared with that of the original design.