• Journal of Life Science
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• v.21 no.7
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• pp.976-984
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• 2011

Total phenolic content was the highest in 60% ethanol extracts at 21.91 mg/g, and inhibitory activity against tyrosinase of 60% ethanol extracts was higher than ethanol extracts of other concentration. The inhibitory compounds against tyrosinase from Persimmon leaves were purified using Sephadex LH-20, MCI-gel CHP-20 column chromatography with gradient elution. Two purified compounds were isolated as a result. The chemical structures of each compound were determined and identified using $^1H$-NMR and $^{13}C$-NMR, FAB-Mass. The compounds were confirmed as (+)-gallocatechin and prodelphinidin B-3. The tyrosinase inhibitory activities of purified (+)-gallocatechin and prodelphinidin B-3 were 29.5 and 40.2%, respectively. The inhibitory activities of (+)-gallocatechin and prodelphinidin B-3 against melanin biosynthesis in melanoma cell were 32.5 and 46.7%. The safety of essence with tyrosinase inhibitory compounds from persimmon leaves was also assessed by various safety profiles. First, changes in pH (4.90~4.95) and viscosity (23,000~26,000 cP) was not detected for 60 days. Essence also showed stability against temperature and light for 60 days. All these findings suggest that extracts from persimmon leaves have a great potential as a cosmetical ingredient with a potent whitening effect.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.5
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• pp.327-339
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• 1991

The present paper is a histological study of neurosecretory cells in the brain and the thoracic ganglion with the gonadal development in Palaemon serrifer. The reproductive cycle includes the successive stages of the growing period (February-March), the mature period(April-May), the ripe and spent periods(June-August) and the degenerative and resting periods(September-January). The neurosecretory cells are grouped into four types based on Matsumoto(1958) : A-,A'-, B- and E-cells. A- and A'-cells are $80-90{\mu}m,\;B-cell\;is\;30-40{\mu}m$ and E-cell is $10-15{\mu}m$. A- and B-cells are the positive to CHP and AF, while B-cell is the positive only to AF. The secretory grannules of a A-cell are transported to the axon, and at the same time they are discharged through the peripheral membrane. Of the four neurosecretory cells, A- and I-cells show the difference of secretory activity according to the gonad developmental process. In the female, A-cells show secretory activity for the ripe and spent periods, while I-cells show for the mature, ripe and spent periods. In the male, A-cells show secretory activity for the mature, ripe and spent periods, while I-cells show for the growing, mature, ripe and spent periods.

• Research in Community and Public Health Nursing
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• v.14 no.3
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• pp.507-519
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• 2003

Purpose: The purpose of this study was to identify the prevalence, health behaviors, and control of hypertension in rural areas in Korea. Method: A total of 927 subjects above age 20 were selected from the areas which fell under the jurisdiction of the 24 Community Health Center located in Chungcheongbuk-do. The employees in the Community Health Center visited and interviewed patients. Data were collected using a questionnaire from July to October 2002. Result: The result showed that women had higher hypertension prevalence rates than men and the increment of its rate leveled up according to age. The hypertension prevalence rate was significantly high when the monthly income was less than 1 million won, their type of the Medical Insurance was the Guardian, they were only able to read Korean characters, and they were bereaved of spouses. In the Health behavior related to hypertension, the hypertension group showed a significantly lower level than the non- hypertension group in terms of drinking rate, smoking rate, intake of salt and intake of meat. There was no significant difference in the exercise rate and coffee intake rate between these groups. In the degree of the obesity the hypertension group was significantly higher than the non-hypertension group. The factors related to hypertension were that the duration for the incidence of hypertension was 12 to 60 months and took up 41.2%. The places where the medical check-ups occurred were the Community Health Center at 46.6%, the medical institution was mostly hospitals recording 46.5%. There were 66.1% of the targets who knew well about their blood pressure and there were 64.7% people who received education about it. As for the education place, the rate of Community Health Center was mostly high and it stood at 77.0%. In the aspect of the management of hypertension, the targets who took medicine on a regular basis were up to 76.1% and the targets who measured blood pressure once a month happened to be about 46.1 %. The targets who always recorded their blood pressure were 3.8%, chest X-ray as a related examination of hypertension reached 32.6%, electrocardiogram examination was 36.2%, cholesterol and serum lipid examination took up 33.6%, and the eye ground examination took 7.3%, which showed the lowest level of all.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.33-33
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• 2021

예측하기 어려운 복잡한 기후 변화로 인해 수자원 관리측면에서 다양한 방법을 도입하여 해결할 수 있는 방안이 국가적 주요 관심사로 다루어지고 있다. 따라서 투입인력과 소요시간 절감, 장비와 인력진입 불가지역에 대한 정보획득, 높은 공간해상도, 항공측량 대비 높은 경제성 등 다양한 장점의 드론을 이용한 하천지형 특성별 수리특성 분석방안이 필요하다. 본 연구에서는 성연천 하류부지역을 대상으로 위성항법시스템(Global Navigation Satellite System, GNSS) 측량 지형성과와 드론측량(Drone) 지형성과를 지상에 설치된 CHP(Check Point) 좌표 값을 확인하여 두 지형의 정확도를 비교하였으며 HEC-RAS 모형을 이용하여 빈도별 수리특성을 비교 산정하였다. 본 연구는 성연천 하류 480m구간을 선정하고 GNSS를 이용한 실측지형자료와 GCP(Ground Control Point)를 얻기 위해 정확도 검증을 실시하였으며 위성항법시스템(GNSS) 측량과 DRONE RGB측량의 CHP(Check Point) 오차를 비교하여 정확도를 검증하였다. 오차 값이 확인된 위성항법시스템(GNSS)을 이용하여 가상기준점을 선정하고 RTK 모바일스테이션을 설치하여 DRONE LIDAR측량을 통해 지형자료를 취득하였으며 얻어진 지형자료를 HEC-RAS를 통해 입력 후 성연천 하천기본계획에 제시되어진 조도계수와 빈도별 홍수위를 적용하여 연구구간 480m에 대해 100년 빈도의 결과 값을 비교 검토하였다. 100년 빈도 계획 홍수량 조건의 하상과 한계수위의 차에서 위성항법시스템(GNSS) 측량 지형자료를 기준으로 평균수위 측정오차는 드론 RGB 측량 지형자료 0.460m, 드론 LIDAR 측량 지형자료 0.260m의 결과를 얻었으며 동일 조건 흐름하의 평균유속에서 위성항법시스템(GNSS) 측량 지형자료를 기준으로 평균유속 측정오차는 드론 RGB 측량 지형자료 0.40m/s, 드론 LIDAR 측량 지형자료 0.36m/s의 결과를 얻었다. 통수 단면적의 비교 결과는 위성항법시스템(GNSS) 측량 지형자료를 기준으로 드론 RGB 측량 지형자료 전체 단면의 평균오차는 20.20m², 드론 LIDAR 측량 지형자료 전체 단면의 평균오차는 21.68²의 결과를 얻었으며 이상에서와 같이 홍수위와 평균유속, 통수 단면적의 측정오차 비교 결과를 종합할 때 통수 단면적 측정결과는 위성항법시스템(GNSS) 측량과 드론 RGB 측량의 차이가 적었으나 계획 홍수량 조건의 하상과 한계수위 차이와 동일조건 흐름하의 평균유속에서 위성항법시스템(GNSS) 측량과 드론 LIDAR 측량의 차이가 적은 것으로 나타났다. 그리고 통수용량(capacity)(m³) 비교에서는 위성항법시스템(GNSS) 측량을 기준으로 드론 RGB 측량은 약 7644m³, 드론 LIDAR 측량은 약 7547m³의 차이를 보여 드론 LIDAR를 이용한 결과가 가장 정확한 측정방법으로 추천할 수 있음을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.72.1-72.1
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• 2010

지금까지 연료전지 시스템의 효율을 극대화시키기 위한 기술들이 개발되어 왔는데, 대표적인 방법은 CHP(Combined Heat & power)와 FCT(Fuel cell & Turbine) Hybrid 시스템이다. 그러나 본 연구의 기술은 연료전지 배열을 이용한 Coanda 공기증폭기를 장착한 새로운 개념의 고효율 연료전지 시스템이다. 원래 공기 증폭기는 완만한 곡면 주위를 흐르는 유체가 곡면의 표면을 따라 흐름의 방향이 바뀌는 원리(Coanda Effect)를 이용한 장치로서, 소량의 고압유체를 구동 에너지원으로 사용하여 최고 20배에 해당하는 많은 양의 주변 유체를 빠른 속도로 이송시키는 역할을 한다. 문제는 고압의 유체원을 만드는 것인데, 본 연구에서는 발전용 연료전지 시스템의 배기가스를 활용하여 먼저 고압의 수증기를 발생시키고, 다음으로 고압의 수증기를 공기 증폭기의 구동원으로 사용함으로써 연료전지 시스템의 Air blower를 대체하는 것이다. 이러한 개념을 검증하기 위해서 고압의 스팀작동 Coanda 공기증폭기를 제작하여 선행실험을 진행하였다. 먼저 공기증폭기의 Gap 및 스팀압력에 따른 공기유량, 압력 등의 기본특성을 조사하였고, 출력 공기의 특성을 개선하기 공기증폭기의 형상 및 재료를 새롭게 설계하였다. 그리고 실제 시스템의 적용가능성을 알아보기 위해서, 예로 300kW급 용융탄산염 연료전지 발전시스템의 Air blower 대체가능성을 확인하였고, 배열이용 Coanda 공기증폭기를 활용한 고효율 연료전지 시스템의 개념설계를 수립하였다. 결론적으로 본 기술을 활용하면 연료전지 시스템의 최종 전기효율을 향상시킬 뿐 아니라는 시스템의 장기 신뢰성을 증대시키는 효과를 기대할 수 있다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.248-257
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• 2010

An exhausted heat recovery system for a small gas engine cogeneration plant was investigated. The system was designed and built in a 300 kW class cogeneration demonstrative system. The basic performance was tested depending on load variation, and installed to a field site as a bottoming heat and power supply system. The exhaust gas heat exchangers (EGHXs) in shell-and-tube type and shell-and-plate type were tested. The entire efficiency of the cogeneration system was estimated between 85 to 90% under the 100% load condition, of which trend appears higher in summer due to the less thermal loss than in winter. Power generation efficiency and thermal efficiency was measured in a range of 31~33% and 54~57%, respectively.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.13-19
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• 2015

The wood pellet is standardized of woody type fuel which of small cylindrical shape that is produced compress wood remnants in process of woody processing. The pellet is critical energy which expects to increase of the amount used in future. It consumes fuel which of home, common facilities stove and boiler, district heating, and CHP, etc. This study was to develop a movable pellet manufacturing equipment that can be mounted on a truck. The pellet production volume is approximately 309kg per hour, daily output is about 2ton. One days work based on the expected revenue of approximately \268,000 feasibility is considered sufficient.

• Journal of Energy Engineering
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• v.18 no.1
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• pp.37-48
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• 2009

Recently, the significance of Green-Energy led by low-carbon Green-Development is increasing as well in Korea. Among them, the most practical solution is the cogeneration which performs the best energy efficiency. This paper addresses the two of RCS(Regional Cogeneration System) connecting heat each other. It is conducted to quantitatively evaluate algorithm that optimally operate the heat transaction considering various operating modes. The proposed method is tested using the real system. Through the case studies, it is verified that the proposed algorithm of heat transaction can evaluate availability.

• Journal of Korean Academy of Nursing
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• v.42 no.7
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• pp.965-973
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• 2012

Purpose: The purpose of this study was to evaluate a self-care program for elders with osteoarthritis managed by primary health care workers, Community Health Practitioners (CHPs), in rural Korea. Methods: The self-care program, consisting of 7 areas, was evaluated with a randomized experimental study for patients over age 60 with osteoarthritis in which 150 participants in the experimental group and 140 in the control group were compared. The self-care program was implemented for six weeks, 2 hours per week, at community health posts by CHPs. Data were collected using an interview questionnaire given by the CHPs and laboratory tests before and after the intervention for both groups. Propensity score matching analysis was done to test effectiveness after controlling for confounding variables. Results: The intervention group showed a significant decrease in the number of painful joints (p<.001) and a significant increase in self-care ability (p<.05) compared to the control group. Conclusion: Study results indicate that training and utilizing primary health care workers in rural areas is valuable in increasing the generalization and continuity of intervention programs. As arthritis should be managed life-long, CHP directed self-care programs are useful interventions for rural elders with arthritis to learn self-care management.

• Advances in Energy Research
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• v.4 no.1
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• pp.29-45
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• 2016

There has been a growing interest in the recent time for the development of solar power tower plants, which are mainly used for utility scale power generation. Combined heat and power (CHP) is an efficient and clean approach to generate electric power and useful thermal energy from a single heat source. The waste heat from the topping Brayton cycle is utilized in the bottoming HRSG cycle for driving steam turbine and also to produce process steam so that efficiency of the cycle is increased. A thermal storage system is likely to add greater reliability to such plants, providing power even during non-peak sunshine hours. This paper presents a conceptual configuration of a solar power tower combined heat and power plant with a topping air Brayton cycle. A simple downstream Rankine cycle with a heat recovery steam generator (HRSG) and a process heater have been considered for integration with the solar Brayton cycle. The conventional GT combustion chamber is replaced with a solar receiver. The combined cycle has been analyzed using energy as well as exergy methods for a range of pressure ratio across the GT block. From the thermodynamic analysis, it is found that such an integrated system would give a maximum total power (2.37 MW) at a much lower pressure ratio (5) with an overall efficiency exceeding 27%. The solar receiver and heliostats are the main components responsible for exergy destruction. However, exergetic performance of the components is found to improve at higher pressure ratio of the GT block.