• 설비공학논문집
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• 제11권3호
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• pp.301-312
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• 1999

Experiments were carried out to evaluate performance of the cold air distribution systems with an ice storage tank in test room. Cold air distribution systems provide primary air for comfort conditioning or process cooling at coil discharge temperatures$4^{\circ}C$ to$11^{\circ}C$. The application of a cold air distribution system allows for the downsizing of air distribution equipment and central plant equipment when ice storage tank is used. The benefit of a cold air distribution system include a decrease in the floor-to-floor height, increase floor space, reduced building capital costs, reduced energy use and demand. The use of cold air distribution can result in the most cost effective system and is currently being implemented world wise as the new standard in air conditioning systems. In this study, the cold air distribution system is compared with the general ice storage system. Under the same cooling load conditions, experimental results show that the supply air volume of cold air distribution system decrease 38%, and decrease 45% flow rate of brine for the general ice storage system.

• 대한기관식도과학회지
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• 제4권1호
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• pp.96-100
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• 1998

Lymphangiomas are congenital malformations of the lymphatic system. Cervicofacial lymphangioma represents 75% of all lymphangiomas. Surgical excision has been the treatment of choice, however the reported results have been unsatisfactory. Various sclerosants have been tried to treat lymphangiomas, with variable results and considerable side effects. Herein we report the results of treatment using intralesional picibanil for lymphangioma. Between January 1996 and January 1998, 16 patients with lymphangiomas, 10 boys and 6 girls, were treated with intralesional picibanil injections. All cases were treated as a primary therapy. Eight lymphagiomas were located in the neck, and 2 in the cheek, 2 in the parotid, 2 in the trunk, 1 in the oropharynx, 1 in the thigh. Dose and method of intralesional injection was similar to that reported by Ogita in 1987. Complete regression was observed in 10 cases and marked regression(> 75% size decrease) in 2 cases and moderate regression(75%-25% size decrease) in 2 cases and poor regression(< 25% size decrease) in 2 cases. No serious side effect was observed except fever lasting for 2-3 days. Intralesional injection of picibanil for lymphangiomas represents a safe, easy and effective way of treatment with high success rate. Picibanil injection can be used as a primary therapy for lymphangiomas.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 추계 학술논문 발표대회
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• pp.157-158
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• 2019

As the aggregate supply and demand shortages in Korea due to the lack of aggregates due to the regulation of production and use conditions of domestic aggregate collectors, the media recently pointed out the distribution of so-called bad aggregates containing soil powder. Such poor aggregates have a high self-absorption rate according to the reference, etc., leading to a decrease in the fluidity of the concrete. Therefore, in order to secure fluidity, the unit quantity increases greatly from $30kg/m^3$ to $55kg/m^3$, and the increased unit yield eventually leads to a decrease in compressive strength, resulting in a decrease in strength from about 35% to 45% compared to general aggregates. It indicates that there is a risk of shortening the life of the structure. Therefore, this study aims to analyze the effect of aggregate soil on concrete.

• Design & Manufacturing
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• 제15권4호
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• pp.51-56
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• 2021

Piercing is the process of shearing a circular hole in sheet metal, whose high shear force makes it difficult to secure the durability of tools. In addition, uneven clearance between tools due to poor alignment of the piercing punch causes accelerated die wear and breakage of the tool. This study reviewed the feasibility of in-situ determining alignment failure during the piercing process by analyzing the signal deviation of a bolt-type piezo sensor installed inside the tool whose alignment level was controlled. Finite element analysis was performed to select the optimal sensor location on the piercing tool for sensitive detection of process signals. A well-aligned piercing process results in uniform deformation in the circumferential direction, and shearing is completed at a stroke similar to the sheet thickness. Afterward, a sharp decrease in shear load is observed. The misaligned piecing punch leads to a gradual decrease in the load after the maximum shear load. This gradual decrease is due to the progressive shear deformation that proceeds in the circumferential direction after the initial crack occurs at the narrow clearance site. Therefore, analyzing the stroke at which the maximum shear load occurs and the load reduction rate after that could detect the misalignment of the piercing punch in real-time.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.519-525
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• 2024

In this paper, a study on the physical properties of mortar applying 3D Textile was conducted to compensate for the shortcomings of the existing concrete surface repair and reinforcement method. In the tests conducted to analyze the physical properties, compressive strength, flexural strength, and dynamic modulus measurement tests were conducted. As a result of the compressive strength test, as the number of surfaces to which the stereoscopic fiber was applied increased, the amount of displacement and strength reduction rate increased, and the flexural strength also increased as the number of surfaces to which the stereoscopic fiber was applied increased. In addition, it was confirmed that the use of stereoscopic fibers tended to decrease the dynamic modulus of elasticity. This result is a characteristic of the application of stereoscopic fibers, and it caused a decrease in compressive strength due to a decrease in the mortar content of the part to which the stereoscopic fib er was applied, and the high tensile force of the stereoscopic fiber is believed to have affected the increase in flexural strength.

• 한국환경과학회지
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• 제27권4호
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• pp.251-259
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• 2018

This study was conducted to determine the effects of combination of air temperature and soil water content on the growth, physiological disorder rate, and yield of hot peppers. The study was carried out in a typical plastic house (open on one side and with ventilation fans on the other side), which was maintained with gradient air temperature (maximum difference in air temperature: $6^{\circ}C$). The deficit irrigation (DI) treatment commenced 65 days after transplanting. The height of plant and fresh and dry weights of the stem increased at high air temperature (ambient + $6^{\circ}C$, extreme high temperature; EHT). Furthermore, the leaf area decreased significantly with the DI treatment. There were no significant differences in the stem diameter, number of branches, and fresh and dry weights of the leaves among all the treatments. The net photosynthesis rate of the full irrigation (FI) treatment was higher than that of the DI treatment. The photosynthesis rate at ambient air temperature was $19.7{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$, the highest among all the treatments; however, the photosynthesis rate of the EHT treatment decreased by 60% ($12.3{\mu}mol\;CO_2m^{-2}{\cdot}s^{-1}$). Additionally, the formation of guard cells in the leaf was abnormal with the EHT treatment, and there was a decrease in translocation efficiency. The effects of air temperature treatment were more pronounced on the physiological disorder rate and yield. The physiological disorder rate of the EHT treatment was the highest under the DI treatment condition. The yield of the AFI (ambient air temperature with full irrigation) treatment was 3,771 kg/10a, the highest among all the treatments; however, the yield of the EHT treatment with DI and FI was 1,282 and 1,327 kg/10a, respectively. These results indicate that growth and physiological disorder rate improved with the EHT treatment; however, there was a decrease in yield. Furthermore, the formation of guard cells was abnormal and malfunctional.

• 수산해양교육연구
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• 제28권4호
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• pp.1006-1013
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• 2016

돌기해삼 종묘의 보관에 따른 외상, 부위별 움직임 및 생존율을 관찰하였다. 10, 15, 20 및 $25^{\circ}C$에 종묘를 3, 6, 12, 24시간 보관 후 회복과정을 통해 생존율을 관찰하였고, 이를 위해 외상정도와 네 가지 부위별 움직임 변화(촉수 움직임, 촉수를 제외한 몸의 움직임, 뒤집기, 이동)를 적용할 수 있는지 검증하였다. 외상정도는 $20^{\circ}C$에서 24시간 실험구와 $25^{\circ}C$의 12시간 실험구에서 각각 $2.2{\pm}0.8$, $2.6{\pm}0.7$로 낮게 나타났다. 부위별 움직임 변화는 촉수의 움직임과 이동 여부 항목에서 생존율 및 외상 정도와 관련성을 보였다. 생존율은 보관 온도 $10^{\circ}C$와 $15^{\circ}C$ 실험구에서는 24시간까지, $20^{\circ}C$는 12시간까지 그리고 $25^{\circ}C$에서 6시간까지는 변화가 없었다. 돌기해삼 종묘의 보관 온도에 따른 치사시간(LT10)은 $20^{\circ}C$의 경우 15.73시간 이었으며, $25^{\circ}C$의 경우 5.57시간 이었다. 본 연구결과는 방류종묘의 운송에 따른 생존율을 간접적으로 파악할 수 있는 지표로서 적용 가능할 것이다.

• 한방비만학회지
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• 제20권1호
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• pp.20-30
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• 2020

Objectives: The purpose of this study is to verify the effects of H Gambitang (GB-001) on body composition and basal metabolic rate in pre- and post-menopausal obese woman retrospectively. Methods: The study was conducted on 57 middle-aged obese women. They were divided into two groups; pre-menopausal obesity group (Pr-MOG; n=34) and post-menopausal obesity group (Po-MOG; amenorrhea was continued to 14~48 month, n=23) with no significant difference of age, height, body weight and body mass index. All subjects took herbal medicine 3 times a day, for 6 weeks during treatment period. The weight, height, body fat mass, skeletal muscle mass, and basal metabolic rate of all subjects were measured on first visit. The following measurements were repeated after 2 weeks (2nd), 4 weeks (3rd) and 6 weeks (4th) with Inbody 370 (Biospace) equipment to identify changes of body fat mass, skeletal muscle mass, and basal metabolic rate. Results are represented as mean and standard deviation. Results: Po-MOG showed significantly lower decrease rate in weight reduction on 2~6 weeks while significantly higher decrease rate in skeletal muscle reduction on 4~6 weeks. There were no significant differences between two groups in body fat reduction rate and basal metabolic increasing rate. Conclusions: H Gambitang (GB-001) can be used not only in Pr-MOG but in Po-MOG in weight loss although the effect can be lower in Po-MOG. To prevent skeletal muscle mass loss in Po-MOG, following study on adjusting dose and components of H Gambitang (GB-001) thought to be necessary.

• The Korean Journal of Physiology
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• 제30권1호
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• pp.43-51
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• 1996

This study was aimed to elucidate the changes in heart rate variability during treadmill exercise at various speeds and grades by spectral analysis. Thirty-three untrained male college students aged $20{\sim}26\;yr $were employed to exercise on a treadmill using 4 speeds (4.02, 5.47, 6.76 and 8.05 km/h) and 6 grades (0, 4, 8, 12, 16 and 20%). A fixed speed was selected for each session with the grade increased every 3 min. The electrocardiogram, respiration and the stepping activity were continuously recorded through an A/D converter system on the computer disk. Power spectra of heart rate variability (RRV) were obtained by use of a fast Fourier transform algorithm. The frequency domain was divided into 3 bands: $VLF\;(0{\sim}0.04\;Hz),\;LF\;(0.04 {\sim}0.15\;Hz)\;and\;HF\;(0.15{\sim}1.00\;Hz).$ Heart rate was $74.4{\pm}2.1\;beats/min$ at rest and showed a steady increase during treadmill exercise with increasing speed and grade up to $196.7{\pm}5.0\;beats/min.$ Total power of HRV was $35.0{\pm}6.7\;(beats/min)^{2}$ at rest and progressively decreased during exercise down to $1.9{\pm}0.3\;(beats/min)^{2}.$ The %VLF power of HRV was $34.5{\pm}3.7\; %$ at rest and showed no significant change during exercise except for a decrease observed at the highest intensity of exercise. The %LF power was $44.1{\pm}3.0\;%$ at rest and showed a progressive decrease down to $4.5{\pm}1.0\;%$ during those stages of exercise where heart rate was over 135 beats/min. The %HF power was $21.4{\pm}2.9\;%$ at rest and showed a progressive increase up to $87.1{\pm}6.7\;%$ during higher intensity exercise where heart rate was over 165 beats/min. Peak frequency of HF band was $0.200{\pm}0.018\;Hz$ at rest and was shifted to higher frequencies up to $0.909{\pm}0.048\;Hz$ at heart rates greater than 135 beats/min. Respiratory frequency was $18.0{\pm}1.5$ breaths/min at rest and significantly increased during exercise up to $53.0{\pm}3.7$ breaths/min. Stride frequency during treadmill exercise showed an increasing tendency with increasing speed from $55.6{\pm}0.9$ steps/min at 4.02 km/h to $81.2{\pm}0.6$ at 8.05 km/h. It was concluded that total power of HRV decreased progressively with increasing exercise intensity due to the withdrawal of parasympathetic activity. At higher exercise intensity, % LF power decreased and %HF power increased with its peak frequency shifted to higher values in a progressive mode with increasing speed and grade, reflecting a readjustment in the cardiovascular system and the increased respiration and its rate, respectively.

• 응용통계연구
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• 제32권4호
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• pp.463-483
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• 2019

2000년 이후 우리나라 합계출산율은 일본, 독일, 프랑스처럼 출산율이 상승이나 감소기조에 들어서면 쉽게 변하지 않는 비가역적인 상수형태를 보이는 것과는 다른 양상을 보인다. 또한 2005년 1.08명 최저점에서 서서히 증가해 2015년 1.23명을 보이다가 2016년 1.17명, 2017년 1.05명, 2018년 0.98명으로 급락하고 있다. 이는 마치 경기침체의 더블딥(double dip)과 유사한 형태를 보인다. 본 연구는 이러한 TFR 증감 요인을 규명하기 위해 먼저 TFR에 영향력이 높은 출생아수 추이와 예측, TFR 분해법으로 분해되는 유배우율과 유배우출산율의 추이를 살펴본다. 그리고 이들 변화가 TFR 증감 변화에 어떤 영향력을 나타내는지 살펴보았다. 분석결과 출생아수는 2018년 약 32-33만 명, 2020년 30만 명, 2025년은 23-24만 명 수준을 보일 것으로 추정된다. 유배우율은 1981-2025년까지 지속적으로 감소, 유배우출산율은 2002년 이전까지 감소를 보이다가 2003-2016년 증가추세를 보인후 2017-2025년까지 감소추세로 이어질 것으로 예측되었다. 끝으로 출생아수, 출산율 분해와 통계적 모형으로 살펴본 TFR 향후 추이는 2018년 0.98명, 2020년 0.93-1.11명, 2025년에는 0.76-1.08명으로 분석되었다.