低壓 보일러의 經濟負荷率에 關한 考察

柳炳哲,林載根 군산대학교 1984 群山水産專門大學 硏究報告 Vol.18 No.1

In general, the efficiency of boiler varies with the loading rate, season and the operated year. When the boiler is operated in accordance with the maximum efficiency, it can be possible to save energy. In this experiment, the operating data of three boilers (two-drum D-type water tube boiler, capacity 30t/h, steam pressure 7.5 kg/cm2) were checked and calculated in order to know the amounts of evaporation and consumption of fuel oil, temperature (feed water, fuel oil, exhaust gas and air), the CO2%, the loss of exhaust gas and the calculated boiler efficiency. For the purposes of this study, the boilers were operated and six times checked with 45-100% of the loading rate in summer from 15th of July to 14th of August and in winter from 15th of December to 14th of january in the next for three years. The main results obtained from this study are as follows: 1.The maximum efficiency of boiler was decreased by 0.63% in summer and by 0.49% in winter in a year. 2.The average maximum efficiency of boiler was higher by 1.73% in summer (average 90.49%) than in winter (average 88.76%). 3.The economical loading rates showed 75% in summer and 80% in winter by No. 1 boiler, 85% in summer and winter by No. 2 boiler and 75% in summer and 80% in winter by No. 3 boiler. 4.The total average boiler efficiency with respect to 45-100% of the loading rate was higher by 1.39% in summer (87.84%) than in winter (86.45%). 5.The average temperature of exhaust gas was higher by 12.35℃ in winter (158.28℃) than in summer (145.93℃). 6.The average loss of exhaust gas was higher by 1.13% in winter (6.01%) than in summer (4.88%). 7.When No. 1 boiler was operated on the loading rate in accordance with the maximum efficiency, the fuel cost was down by 2,1000,000 won/ month in summer and 1.080,000 won/month in winter in comparison with± 5% of that condition.

한국 전통담장 및 화계조성 사례 연구 : 상명대 도서관 중정을 중심으로 Base on the Gardening of Sang Myung University Library court

유경상,백난영,이재근 한국정원학회 2002 한국전통조경학회지 Vol.20 No.3

Many studies have been conducted under the grand title as modernization of traditional landscape archit-ectures and there is also growing number of sites where the techniques of traditional landscape architecture have actually been tried. But conventional studies concentrated mainly in theoretical studies of "Kotdam(beautiful wall)", due to its title and scarcity. The studied on the detailed construction methods have been neglected. And what is worse, the wall usually is implamented by the architectural drawing. In the case, due to increase in ghe expenses, the building companies either reduce the size or substituted it with different structures. Thus, in the study, though stuctural issues may be solved with modern methods, it focused on expression of traditional pattern for architectural value and used tile type attaching method which resulted in signif-icant reduction of costs. As a result of the study, efficient way to build traditional pattern of Kotdom is suggested in attaching concept figure, standard model and standard Pumseom(quantity manpower spent per unit).

부비동에 발생한 콜레스테롤 육아종의 치험 5예

김재호,김민관,유근식,이봉재 대한이비인후과학회 2000 대한이비인후과학회지 두경부외과학 Vol.43 No.2

펄스 옥시미터 시스템 구현에 관한 연구

유동주,허 웅,김근이,이호재,임현수 明知大學校 産業技術硏究所 1992 産業技術硏究所論文集 Vol.11 No.-

In this paper, we implemented a pulse oximeter system which is measured oxygen saturation coefficient of a human blood in vivc We use the Beer-Lambert Law to measure the percentage of hemoglobin is oxygen saturation. The oximeter sensor are consisted of two LED(RED and INFRARED LED) and a single photodiode. The photodiode measures lights which transmitted through the tissue from two light source alternately, We calculated a ratio of light transmittance between two LEDs and then, it applied for the oxygen saturation coefficient calculation to formula. As a result, the oxygen saturation coefficient that measured from normal conditions men was 96.43[%]

4주간의 육미지황탕 투여가 최대하운동시 근대 5종 선수들의 혈액성분 및 혈액가스성분 변화에 미치는 영향

오재근,최용어,서인원,조준용,유루리 韓國體育大學校 1997 論文集 Vol.20 No.-

The purpose of this study was to estimate the changes of blood components and blood gases on submaximal exercise after Yuk-mi-ji-Whang-tang administration during 4 weeks. Ten modern pentathlon athletes participated as subjects of this study. The result and conclusion of this study is as follows; The changes of blood components on pre-, post-sumaximal exercise and during recovery time was not significant difference in Yuk-mi-ji-whang-tang administration group except for WBC(p<.05.). But comparative observation of blood gases levels such as pH, PCO₂, PO₂, HCO₃, O₂SAT, O₂CT was showed a tendency of being lower acidity, higher PO₂, lower PCO₂on pre-, post-sumaximal exercise and during recovery time in Hyang-sa-pyung-yi-san than in Yuk-mi-ji-whang-tang administration group.

설계변경의 경향 및 원인 분석을 통한 설계 품질향상 방안

석성재,김재근,이철우,홍순구,유춘번 한국품질경영학회 2000 품질혁신 Vol.1 No.1

This study is prepared to introduce design quality improvement measures by the trend and cause analysis of design changes which have been made during operations of construction project for power plant. In this study, two types of analysis tool have mainly taken for the use of the improvement measures. One tool is the trend analysis to identify which action should be taken to cut down design changes. This is also useful to monitor whether project participant's endeavour for the action taken is effective or not, to the project performance and design quality improvement. The other is the cause analysis, by using cause and effect diagram, which is useful to identify main causes of the design changes and to establish the measures to reduce recurrence of the design changes.

발포폴리스티렌비드를 사용한 경량콘크리트의 역학적 특성에 관한 실험적 연구

주재금,이종찬,오세출,유택동,정광량,서치호 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.1(구조계)

The purpose of this study is to obtain basic data on the properties of the lightweight concrete within expanded polystyrene beads for various applications in the field. Inquiring into the change of the properties as altering cement matrix mixture and the capacity mixture ratio of expanded polystyrene beads, the mixture plane of this study is set up as W/C is fixed 50%, expanded polystyrene beads is increased 10% from 0% to 80% per 1m³ and the ratio of cement:sand in the cement matrix is 1:0, 1:0.5, 1:1. The results of this study are as follow. The slump as changing the mixture ratio of expanded polystyrene beads decrease smoothly until mixture ratio 50% but decrease rapidly being in excess of 50%. The density decrease regularly as the mixture ratio of expanded polystyrene beads increase but the ratio of strength decrease. The difference of cement matrix. The strength of cement matrix having more sand mixture ratio relatively decrease rapidly as increasing the mixture ratio of expanded polystyrene beads. It is judged decreased strength phenomenon as the quantity of coherent material created in the mixture decrease rapidly.

비만 지표와 흡연,음주,지질,혈당 및 혈압과의 관계

이재근,유병연,조동영 건국대학교 의과학연구소 2000 건국의과학학술지 Vol.10 No.-

It is well known that obesity is an important cause of risk factor of cardiovascular disease, emphasized by many studies and cardiovascular disease has been found to correlate not only to the extent of obesity, but also the fat distribution of the individual. Recently, focusing on obesity of the abdomen, we were able to evaluate the significance of obesity indices by examining correlations between these indices and the risk factors of cardiovascular disease. Three hundred sixty four health examined persons through out-patient department of family medicine, Seoul hospital of Konkuk medical center were chosen as subjects of this study but finally one hundred twenty five examined persons were selected. The auther analysed correlations between obesity indices and cardiovascular risk factors by measuring serum lipid levels, fasting blood glucose levels and blood pressure that are thought to be risk factors of cardiovascular diseases and obesity indices were calculated using anthropometric measurements. The abdominal obesity indices and risk factors of cardiovascular disease, the levels of total cholesterol in the serum, fasting blood glucose levels, systolic and diastolic blood pressure, increased significantly according to age and there was a significant difference in the abdominal obesity indices according to drinking and smoking habits. Systolic and diastolic pressures had significant differences according to the presence or absence of an alcohol drinking history. There were negative correlatons between HDL-cholesterol and obesity indices(r = -0.248, -0.215, -0.204, -0.256, -0.201) and the weakest correlaton was found or noted between fasting blood glucose level and sagittal diameter. Among obesity indices, sagittal diameter and sagittal diameter per height may be important prognostic indicators or risk factors of cardiovascular disease.

황사의 지속시간에 따른 대기 중 농도변동 및 종관기상장 특성

김유근,송상근,강재은 한국대기환경학회 2004 한국대기환경학회지 Vol.20 No.4

We determined Asian dust days by constructing the standard of Asian dust using PM_10 concentrations (≥150 ugm-³, 24-hr average) and TOMS aerosol index (≥0.7) for 5 years (1998-2002), and grouped into long-lasted cases (LLCs, ≥4 days) and short-lasted cases (SLCs, ≤2 days) concerning the mean lasting time (about 3 days) of Asian dust. Further we performed the specific analyses associated with concentration variations and synoptic conditions by using PM_10 and TOMS data, weather maps during the dusty cases (LLCs and SLCs). As a result, the LLCs (9 cases) had large variations of PM_10 concentration as the mean of 131 ugm-³ and the maximum mean of 379.8 ugm-³, and showed dominant features the continuous passage of deep trough caused by blocking effect and weak trough (56%, 5 cases) over Korea. The SLCs (11 cases) had relatively small variations of PM_10 concentration as the mean of 133.3 ugm-³ and the maximum mean of 247.2 ugm-³, and showed passage of one weak trough (64%, 7 cases) over Korea. Thereafter, the case studies (April 7-13, 2002 of LLC and March 23-24, 2000 of SLC) performed by the simulation of MM5 with meteorological variables of the horizontal wind, potential temperature, isentropic potential vorticity, and helped to better understand the features of synoptic conditions in connection with the concentration variations for each case.

법랑질 접착에 대한 습윤 효과

고근호,조영곤,진철희,유상훈,김종욱,박병철,기영재,최희영,김종진 大韓齒科保存學會 2004 Restorative Dentistry & Endodontics Vol.29 No.3

This study evaluated the microleakage and interfacial gap between enamel and composite resin under the dry and wet condition of the enamel surface, V shaped class 5 cavities were prepared on the occlusal portion of extracted human molars. Samples were divided into three groups: D group (air dry for 10-15s), BD group (blot dry with moist cotton pellet), and DR group (air dry for 10-15s and rewet with Aqua-Prep F for 20s). Cavities were filled using Aelitefil composite resin after applied One-Step. Microleakage was tested by 2% methylene blue dye solution and the data were statistically analysed by Kruskal-Wallis test and Mann-Whitney test. Also Enamel-resin interface was observed under SEM. Group BD showed statistically lower microleakage than group D (p〈0.05). but there was no statistically significant difference between group BD and DR (p)0.05). At the enamel-resin interface, group D showed the gap of 2 ㎛ thickness, but group BD and DR showed close adaptation. In conclusion, the use of blot dry and rewetting agent (Aqua-Prep F) resulted in decreased microleakage and improved adhesion between enamel and resin when using One-Step.