• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.942-944
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• 2017

초고속 비행체는 발사 시 엔진에 의한 음향 압력과 비행 중 공력 가열 및 공기역학적 압력 등 복합적인 하중을 받는다. 이러한 외부환경으로부터 비행체의 연료 탱크 등 내부 시스템을 보호하기 위해 열방어 시스템 패널(Thermal Protection System Panel)이 필요하다. 본 논문에서는 온도 조건에 대해 유한차분법을 이용하여 열방어 시스템 패널의 열전달 모델을 정의하고, 구한 절점별 온도 데이터를 회귀분석을 통해 두께방향 온도 구배의 함수로 정리하였다. 도출한 온도 이력과 극한 압력 하에서 열방어 시스템 패널의 열구조 특성에 대한 해석적 모델을 정의하였다. 해석적 모델을 이용하여 열방어 시스템 패널의 열구조 특성에 대해 매개변수 분석을 수행하였다. 이를 통해 열방어 시스템 패널의 경량화 및 열구조적 설계 요구조건을 충족하는 설계변수를 도출하였다.

• 한국자원식물학회지
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• 제28권4호
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• pp.400-410
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• 2015

Juniperus chinensis (Cupressaceae) is a valuable woody plant resource, but this rare plant is only distributed in restricted regions in Korea. In this study, we surveyed the geographic distribution regions, variation of sex ratio and the dynamics of natural populations of J. chinensis. in order to establish conservation strategies for the sustainable conservation of this important resource tree. The 17 natural populations of J. chinensis are restrictively distributed in the shore cliffs of (1) Ulleungdo island, (2) Gyeongju-si to Gangneung-si of the eastern coast, the riverside cliff along (3) Donggang-river of Jungsun-gun and Pyeongchang-gun and (4) branch of Nakdonggang-river in Uiseong-gun. The populations in Ulleungdo island showed continuous population distribution of over 200 individuals, but populations in other regions had discontinuous population distribution of under 200. The population of J. chinensis surveyed in Korea was estimated in ca. 3,200 individuals. The sex ratio (male/female) among populations of J. chinensis was diverse with variation from 0.46~1.67 range, but showed no significance. The sex ratio of the total individuals by species level was 0.74, and the percentage of female tree was significantly higher than the male. The results of dynamics analysis within population among regions showed that seedlings and saplings of J. chinensis in three regions surveyed were continuously regenerating. The distribution of DBH class showed a stable population structure of inverse J shape graph, but fragmentation and decrease in populations because of invading broad-leaved shrubs and trees from the surroundings were concerned. Further studies, and in situ and ex situ conservation strategies for the sustainable conservation on natural populations of this rare resources woody plant, J. chinensis in Korea are recommended.

• 미생물학회지
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• 제27권4호
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• pp.342-347
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• 1989

Fusarium 속의 20균주를 PDA 배지에서 배양하고. HCI-Giemsa 염색법을 이용하여 균사 내에서의 영양핵의 핵분열을 관찰하였고, 염색체 수를 세었다. 관찰한 모든 Fusarium 속의 균주들익 염색체 수는 4-8개 사이에 있었다. 그 중에서 3균주인 F. solari S Hongchun D4. F. moniiforme(from banana), F. raphani (from radish)는 n=8개이고, F, solani 7468(from Sydney), F, solani 7475 (from Sydney), F, oxyporum (from tomato), F, oxyporum(from tomato). F F. roseum(from rice), F, sporotrichioides C. Jungsun 1, F. avenaceum C Kosung 6. F, avenaceum46039 등의 7균주에서는 n=7개였다 F. monilzfonne (from rice), F. graminellrum, F. probiferatum 6787(from Sydney), F. anguioides ATCC20351의 5균주는 n=6개 F. moniliforme NRRL2284. F. poae NRRL3287. F. tricintum NRRL 3299의 3균주는 n=5개였고 가장 적은 수의 n=4개인 균주로는 F. sporotrichioides NRRL3510과 F. equiscli KFCC 11843 IFO 030198의 3균주였다. 이상의 균주들의 염색체 수를 비교 고찰할 때 Fusarium 속의 기본 염색체 수는 반수체가 4개이며 종 분화과정에서 이수체와 배수체가 되었을 것으로 추론된다.

• 한국전자파학회논문지
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• 제28권2호
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• pp.113-119
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• 2017

본 논문에서는 국내 RFID/USN 주파수 대역의 Duty Cycle 기술기준 하에서 광역 IoT 망의 하나인 LoRa 기기의 성능분석 결과를 제시하고, LoRa 기술의 활성화를 위해 기술기준 개정이 필요함을 제안한다. 무선기기는 국가별로 전파법 및 무선설비규칙을 준수하여야 하므로 나라별로 기술기준이 다를 경우 그 성능에 차이가 있을 수 있다. 따라서 향후 IoT 기술의 발전을 위해서는 국내 기술기준에 따른 LoRa 기술의 성능의 한계를 아는 것은 매우 중요하다. 분석 결과, 국내 RFID/USN 주파수 대역의 Duty cycle 기술기준인 0.4초 이내로 데이터 송신을 마치도록 한 규정에 따라 단일 LoRa 기기의 성능이 크게 제한됨을 알 수 있었다. 이에 따라 LoRa IoT 망의 활성화를 위해서는 EU와 유사하도록 국내 Duty Cycle 기술기준을 개정할 필요가 있다고 판단된다.

• 정보과학회 논문지
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• 제42권5호
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• pp.580-590
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• 2015

최근 그린 컴퓨팅의 일환으로 데이터센터의 효율적인 전력관리가 부각되고 있으며, 이러한 효율적인 데이터센터의 전력관리를 위해서는 서버 모니터링이 필수적이다. 하지만 기존 서버 모니터링 기법은 주로 데이터베이스만을 이용해 관리하였기 때문에, 관리자는 데이터센터 및 데이터베이스의 구조를 명확하게 알고 있어야 하고, 관측한 데이터 간 상관관계를 분석해야 한다. 또한 관리자는 데이터베이스에 명시되지 않은 부분에 대한 모니터링이 불가능하다. 이에 본 논문에서는 효율적인 데이터센터 내 전력관리를 위한 온톨로지 기반의 모니터링 기법을 제안한다. 제안된 기법은 서버관리를 위한 도메인 온톨로지를 구축하고, 구축한 온톨로지를 시맨틱 어노테이션 기술을 통해 데이터베이스와 연동하였으며, 서버의 상태 및 질의문 생성에 대한 규칙을 정의하였다. 그리고 제안하는 기법의 유효성 입증을 위해 온톨로지 기반 모니터링 시스템 아키텍처를 설계하고, 지식 체계를 구축하였으며, 파일럿 시스템을 구현하여 검증을 실시하였다.

• Safety and Health at Work
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• 제9권1호
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• pp.75-78
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• 2018

Background: To identify work sectors with high risk for work-related musculoskeletal disorders (MSDs) in Korean men and women. Methods: We analyzed nationwide data to identify ergonomic risk factors in Korean employees. In particular, we analyzed data on exposure to five ergonomic risk factors (painful/tiring postures, lifting/moving heavy materials, standing/walking, repetitive hand/arm movements, and hand/arm vibration) according to employment sector, sex, and age, using the 2014 Fourth Korean Working Conditions Survey. We also used workers' compensation data on work-related MSDs in 2010, which is available by sex. Results: The different work sectors had different gender distributions. "Manufacturing" (27.7%) and "construction" (11.3%) were dominated by males, whereas "human health and social work activities" (12.4%), "hotel and restaurants" (11.7%), and "education" (10.4%) were dominated by females. However, "wholesale and retail trade" and "public administration and defense" employed large numbers of males and females. Furthermore, the work sectors with a greater proportion of work-related MSDs and with multiple ergonomic risk factors were different for men and women. For men, "construction" and "manufacturing" had the highest risk for work-related MSDs; for women, "hotel and restaurants" had the highest risk for work-related MSDs. Conclusion: Ergonomic interventions for workers should consider gender and should focus on work sectors with high risk for MSDs, with multiple ergonomic risk factors, and with the largest number of workers.

• 생약학회지
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• 제46권2호
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• pp.140-147
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• 2015

The antioxidative activities and anti-inflammatory effects of rice bran and wheat bran were investigated. To determine the antioxidant activity, total phenolic content. DPPH reaction, ABTS reaction and FRAP assay were tested. To investigate the anti-inflammatory effect, the inhibition of NO production, IL-6 production and TNF-${\alpha}$ production were observed. The total phenolic contents were 46.4 mg/g in the BuOH fraction of rice bran (RBB) and 69.0 mg/g in BuOH fraction of wheat bran (WBB). EtOAc fraction of rice bran (RBE), EtOAc fraction of wheat bran (WBE), RBB and WBB showed high radical scavenging activity at a concentration of 5 mg/ml. Scavenging activity of DPPH radical were 89.04% in RBB and 91.53% in WBE. Scavenging activity of ABTS radical were 88.53% in RBB and 90.39% in WBB. In case of FRAP assay, RBE reduced 0.805 mM/mg of Fe²⁺ and WBE reduced 1.521 mM/mg of Fe²⁺. RBB, RBE, WBB and WBE showed concentration dependent inhibition of LPS induced NO production (RBE: 57.38%, WBE: 76.85%), IL-6 production (RBE: 92.08%, WBB: 92.57%), TNF-α production (RBE: 86.33%, WBE: 85.05%) at a concentration of 100 μg/ml of each fraction. These results showed that RBB, RBE, WBB and WBE have strong antioxidative activities and anti-inflammatory effects and show the possibilities of a new natural antioxidants and anti-inflammatory medicines.

• 생약학회지
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• 제44권3호
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• pp.269-274
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• 2013

In this study, we investigated the anticancer effect of rice bran extract in HL-60 human promyelocytic leukemia cells. The extract of rice bran inhibited the proliferation of HL-60 cells. When treated with the rice bran extract, we could observe the apoptotic characteristics such as apoptotic bodies and the increase of sub-G1 hypodiploid cell population, increase of Bax level, decrease of Bcl-2 expression, cleavage of procaspase-3, cleavage of procaspase-9 and cleavage of poly(ADP-ribose) polymerase(PARP) in HL-60 cells. Furthermore, the apoptosis induction of HL-60 cells treated with the rice bran extract was also accompanied by the inactivation of mitogen-activated protein kinases (MAPK) such as ERK1/2 MAPK and p38 MAPK. In addition, the rice bran extract induced the down-regulation of c-myc. These data suggested that the rice bran extract could induce the apoptosis via the inactivation of ERK1/2 MAPK and p38 MAPK, and the down-regulation of c-myc in HL-60 acute pomyelocytic leukemia cells. The results support that the rice bran extract might have potential for the treatment of acute promyelocytic leukemia.

• Journal of Korean Medical Science
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• 제33권44호
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• pp.278.1-278.12
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• 2018

Background: We evaluated the association of blood pressure (BP) with blood levels of cadmium, lead, and cadmium and lead together (cadmium + lead) in a representative sample of adolescents from Korea. Methods: We used 2010-2016 data from the Korean National Health and Nutrition Examination Survey. This cross-sectional study enrolled adolescents aged at 10-18 years-old who completed a health examination survey and had blood measurements of lead and cadmium. The association of adjusted mean differences in diastolic and systolic BP with doubling of blood lead and cadmium were estimated by regression of BP against ${\log}_2$-transformed blood metals and their quartiles after covariate adjustment. Adjusted odds ratio for prehypertension were calculated for ${\log}_2$-transformed blood levels of lead and cadmium and their quartiles. Results: Our analysis of adolescents in Korea indicated that blood levels of lead and cadmium were not significantly associated with increased BP or risk of prehypertension. However, the cadmium + lead level was associated with prehypertension. Previous studies showed that blood levels of lead and cadmium were associated with increased BP and risk of hypertension in adult populations. We found no such association in Korean adolescents. Conclusion: We found that the cadmium + lead level was associated with prehypertension. The differences between adults and adolescents are because adolescents generally have lower levels of these blood metals or because adolescents only rarely have hypertension.

• 상하수도학회지
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• 제35권4호
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• pp.285-292
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• 2021

Osmotic power is to produce electric power by using the chemical potential of two flows with the difference of salinity. Water permeates through a semipermeable membrane from a low concentration feed solution to a high concentration draw solution due to osmotic pressure. In a pressure retarded osmosis (PRO) process, river water and wastewater are commonly used as low salinity feed solution, whereas seawater and brine from the SWRO plant are employed as draw solution. During the PRO process using wastewater effluent as feed solution, PRO membrane fouling is usually caused by the convective or diffusive transport of PRO which is the most critical step of PRO membrane in order to prevent membrane fouling. The main objective of this study is to assess the PRO membrane fouling reduction by pretreatment to remove organic matter using coagulation-UF membrane process. The experimental results obtained from the pretreatment test showed that the optimum ferric chloride and PAC dosage for removal of organic matter applied for the coagulation and adsorption process was 50 mg/L as FeCl₃ (optimum pH 5.5). Coagulation-UF pretreatment process was higher removal efficiency of organic matter, as also resulting in the substantial improvement of water flux of PRO membrane.