• 한국산학기술학회논문지
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• 제10권2호
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• pp.222-229
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• 2009

본 논문에서는 루버형 핀 형상을 가진 핀-튜브 열교환기와 알루미늄 평행류 열교환기의 에어컨 응축기 조건에서의 열전달 성능과 공기측 압력강하 특성을 비교하였다. 모든 실험은 ASHRAE 표준에 근거해 제작된 공기엔탈피형 칼로리미터를 사용하여 수행하였다. 관외 측 공기 속도는 0.7-1.6 m/s까지 0.3 m/s 간격으로 변화시켰으며 건구온도는 $20^{\circ}C$, 상대습도는 60%로 유지하였다. 관내 측 물의 입구온도는 $70^{\circ}C$, 유량은 10 LPM로 고정하였다. 알루미늄 열교환기의 열전달 성능은 루버 핀-튜브 열교환기보다 단위체적당, 단위질량당, 단위열전달면적당 약 17-163%정도 높게 나타나는 연구결과를 보였으며 반면에 공기측 압력강하는 핀-튜브 열교환기에 비해 약 19-81% 정도 낮게 나타났다.

• 한국진공학회지
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• 제6권4호
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• pp.308-313
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• 1997

Capacitance Diaphragm Gauge(CDG)를 전달표준기로 사용하여 한국과 영국의 저진 공표준의 국제비교를 수행한 결과 양국 표준기에서 교정한 CDG의 압력비의 차이는 0.05% 이었다. 또한 두 개의 Spinning Rotor Gauge(SRG)를 이용하여 한국과 일본이 고진공표준의 국제비교를 수행한 결과 양국 표준기에서 교정한 SRG의 accommodation coefficient($sigma$)의 차이가 0.4% 이내이었다. CDG와 SRG를 이용한 한국과 영국의 저진공표준기 및 한국과 일 본의 고진공표준기의 국제비교 결과 CDG 및 SRG 자체의 고유오차범위 이내에서 결과가 일치함을 확인할 수 있었다.

• 한국대기환경학회지
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• 제33권3호
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• pp.251-264
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• 2017

Recently, Jeollabuk-do has been reported as a province where the $PM_{10}$concentration is one of the highest levels in South Korea. To explore the characteristics and origins of the $PM_{10}$in Jeollabuk-do, we present one of the first long-term datasets including a statistical analysis of $PM_{10}$concentrations obtained from six cities in the province from 2010 to 2015. During the entire periods, the mean hourly $PM_{10}$concentration was $49.3{\mu}g/m^3$, which correspond to the annual ambient air quality standards for $PM_{10}$in South Korea, and the annual $PM_{10}$concentration of each city showed a similarity in year-to-year variations. In the monthly variation of $PM_{10}$, the $PM_{10}$concentrations showed a maximum value in May that was one of the top levels among the provinces of Korea while the concentrations were dramatically decreased in August showing one of the lowest levels among the provinces in Korea. For the diurnal variation of $PM_{10}$, the $PM_{10}$concentration was enhanced during the rush hours together with gaseous species of $NO_2$, and CO. When the high concentrations of $PM_{10}$were observed (the highest 10% of the $PM_{10}$mass contribution), temperature and relative humidity were low. Using HYSPLIT backward trajectories and cluster analysis for the high $PM_{10}$concentrations, we found that the pollution plumes were transported mainly from China.

• 한국대기환경학회지
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• 제29권6호
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• pp.757-772
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• 2013

In this study, a combination of sorbent tube (ST)-thermal desorption (TD)-gas chromatography (GC)-mass spectrometry (MS) was used for quantitative analysis of liquid phase standards of 10 BVOC ((1) (+)-${\alpha}$-pinene, (2) (+)-${\beta}$-pinene, (3) ${\alpha}$-phellandrene, (4) (+)-3-carene, (5) ${\alpha}$-terpinene, (6) p-cymene, (7) (R)-(+)-limonene, (8) ${\gamma}$- terpinene, (9) myrcene, and (10) camphene). The results of BVOC calibration yielded comparatively stable pattern with response factor (RF) of 23,560~50,363 and coefficient of determination ($R^2$) of 0.9911~0.9973. The method detection limit (MDL) of BVOC was estimated at 0.03~0.06 ng with the reproducibility of 1.30~5.13% (in terms of relative standard error (RSE)). Emissions of BVOC were measured from four types of fruit samples ((1) tangerine (TO), (2) tangerine peel (TX), (3) strawberry (SO), and (4) sepals of strawberry (SX)). The sum of BVOC flux (${\sum}flux$ (BVOC) in ng/hr/g) for each sample was seen on the descending order of (1) TX=291,614, (2) TO=2,190, (3) SO=1,414, and (4) SX=2,093. If the results are compared between the individual components, the highest flux was seen from (R)-(+)-limonene (265,395 ng/hr/g) from TX sample.

• 분석과학
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• 제13권3호
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• pp.357-367
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• 2000

하수슬러지와 토양시료 중 16가지의 다핵방향족 탄화수소(PAH)를 KOH와 $CHE_3OH$에 녹인 용액으로 Soxhlet 추출후 내부표준물질로 2-ethylantracene을 이용하여 GC/MS-SIM 방법으로 분석하였다. 12종의 PAH가 하수슬러지에서 검출되었고 공업지역 하수슬러지 중 가장 특징적인 화합물은 naphthalene($0.78{\mu}g/g$), 도시 하수슬러지에서는 pyrene($0.26{\mu}g/g$)이었으며, 총 PAH는 각각 $1.74{\mu}g/g$과 $1.19{\mu}g/g$이었다. 논 토양과 밭 토양에서의 PAH는 phenanthrene을 포함한 8종이 검출되었으며 그 농도범위는 $0.01-0.04{\mu}g/g$이었고, 총 PAH의 양은 각각 $0.19{\mu}g/g$과 $0.22{\mu}g/g$이었다. 논 토양 중의 총 PAH함량에 비하여 공업지역과 도시지역 하수슬러지 중의 총 PAH양은 각각 9.2배와 6.3배가 높게 나타났다.

• 한국생활과학회지
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• 제13권3호
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• pp.477-484
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• 2004

This paper is an attempt to discuss theoretical and empirical issues embedded in a rapidly dispersing well-being lifestyle in Korea. Increase of people's interests in health and well-being reflects the fact that Korea has been developed socially and economically to the level for common people to pursue the quality of life beyond survival or basic standards of life. The term, well-being life style, was first constructed and has been dispersed through mass media. Media contributes to popularize health issues and to deliver the importance of lifestyle for health promotion to the general public. Well-being lifestyle, initiated by media and joined with commercialism, however, reveal certain negative sides as well. Health or healthy lifestyle in Western societies has been rooted theoretically in the change of health paradigm and the political emphasis on the lifestyle for health promotion in policy implications. Well-being lifestyle in Korea, in lack of theoretical and institutional foundations, is being substantially formed into distorted consumerism. Based on the sociological theories of stratification, it might be necessary to discuss the well-being consumerism in respect of tension among people with different consuming power and the destruction of solid market principles. Considering well-being consumerism as a risk factor to societal well-being, it is also necessary to examine conflicting or misleading information about well-being and to explore the scientific knowledge and principles. All these discussions and examination need to be done with interdisciplinary efforts. Especially, tasks for developing application principles for everyday life are on hands of researchers in living sciences.

• Nutrition Research and Practice
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• 제7권5호
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• pp.409-417
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• 2013

This study was performed to determine the effects of dietary calcium (Ca) intake, milk and dairy product intake, and serum vitamin D level on bone mineral density. The survey data from the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES) for adults (3,819 males, 5,625 females) aged > 20 years were examined; osteoporosis was defined according to the standards for Asian populations (T-score < -2.5). The risk for osteoporosis significantly decreased as Ca intake increased; this effect persisted (quartile 4 vs. quartile 1 of Ca intake: odds ratio [OR] 0.66; 95% confidence interval [CI]: 0.50-0.87) even after adjustment for gender, age, and other factors (body mass index, serum vitamin D, menstruation, female hormone intake, menopausal status, and the number of days per week of muscular strength exercise). Additionally, the risk for osteoporosis significantly decreased as the Ca/P ratio increased (quartile 4 vs. quartile 1: OR 0.76; 95% CI: 0.58-0.98). The degree of risk was 0.96 (0.66-1.38) in those who consumed < 1 portion of milk or dairy products daily, and 0.71 (0.53-0.96) in those who consumed > 1 portion per day, compared with those who had zero intake. The risk for osteoporosis significantly decreased as the serum 25(OH) vitamin D level increased. From these results, we advocate an increase in Ca, milk, and dairy product intake, and that serum 25(OH) vitamin D levels be maintained within the normal range, for the maintenance of bone health and the prevention of osteoporosis in adults.

• 한국수산과학회지
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• 제47권5호
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• pp.459-473
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• 2014

The recent mass appearances of jellyfish in Korea have caused economic and social damage, as they plague swimmers and fishermen. However, jellyfish have high economic and nutritional value, and contain low levels of calories and hydrolysates. Thus, jellyfish are a natural, healthy food that can improve high blood pressure, bronchitis, and a multitude of other diseases. Here, we present research on the ecology, classification, bloom, damage caused, food component characterization, and tissues of jellyfish, with the aim of facilitating further study. Research on use of jellyfish as salted products, and for collagen and qniumucin would also be valuable. A jellyfish body is classified into three parts: the body, termed the umbrella; the oral arm; and the tentacle. Jellyfish are planktonic marine members of a group of invertebrate animals comprising the classes Schypozoa (phylum Cnidaria) and Cuboza. In Korea in 2012, jellyfish damage resulted in decreases of annual catch and commercial value estimated at 177 and 141 billion won, respectively. Because concentrations of heavy metals are below the safety limits for seafood, dried jellyfish appear to be safe raw materials for food. The proximate compositions of Nemopilema nomurai and Aurelia aurita were 97.1% and 96.5% moisture, 0.9% and 1.2% crude proteins, undetected and 0.1% crude lipids, and 1.7% and 1.8% ash, respectively. According to their total contents of essential, total, and non-essential amino acids, jellyfish gonads were deemed good-quality protein. Because the major functional components of jellyfish are collagen and qniumucin, jellyfish can be used salted, or these components of healthy diets can be extracted from them. For more effective use of jellyfish, unit costs should be decreased and safety guaranteed. Additionally, dehydrators attached to conveyor belts should be developed. Since jellyfish can be used throughout the year, they should be listed in the Korean Food Standards Codex as a food source.

• 마이크로전자및패키징학회지
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• 제12권1호
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• pp.65-71
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• 2005

At present, Electronic industries push ahead to eliminate the Pb(Lead) -a hazardous material-from all products. Especially, we have performed to select the optimum standard composition of lead free alloy for the application to products for about 3 years from 2000. These days, we have the chance for applying to the mass-production. This project constructed the system for applying the lead free solders on consumer electronic products, which is one of the major products of the LG Electronics. To select the lead free solders with corresponding to the product features, we have passed through the test and applied with Sn-3.0Ag-0.5Cu alloy system to our products, and for the application to the high melting temperature composition, we secured the thermal resistance of the many parts and substrate and optimized the processing conditions. We have operated the temperature cycling test and the high temperature storage test under the standards to confirm the reliability of the products. On these samples, we considered the consequence of our decision by the operating test. For the long life time of the product, we have operated the temperature cycling test at $-45^{\circ}C\;-\;+125^{\circ}C$, 1 cycle/hour, 1000 cycles. Also we have tested the tin whisker growth about lead free plating on lead finish. We have analyzed with the SEM, EDS and any other equipment for confirming the failure mode at the joint and the tin whisker growth on lead free finish.

• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3817-3824
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• 2013

Various separation modes in HPLC, such as anion exchange (AE), reversed-phase (RP), and affinity (AF) chromatography were examined for the separation of selenium species in human blood serum and urine. While RP- and AE-HPLC were mainly used for the separation of small molecular selenium species, double column AF-HPLC achieved the separation of selenoproteins in blood serum efficiently. Further, the effluent of AF-HPLC was enzymatically hydrolyzed and then analyzed with RP HPLC for selenoamino acid study. The versatility of the hybrid technique makes the in-depth study of selenium species possible. For quantification, post column isotope dilution (ID) with $^{78}Se$ spike was performed. ORC ICP/MS (octapole reaction cell inductively coupled plasma/mass spectrometry) was used with 4 mL $min^{-1}$ Hydrogen as reaction gas. In urine sample, inorganic selenium and SeCys were identified. In blood serum, selenoproteins GPx, SelP and SeAlb were detected and quantified. The concentration for GPx, SelP and SeAlb was $22.8{\pm}3.4\;ng\;g^{-1}$, $45.2{\pm}1.7\;ng\;g^{-1}$, and $16.1{\pm}2.2\;ng\;g^{-1}$, respectively when $^{80}Se/^{78}Se$ was used. The sum of these selenoproteins ($84.1{\pm}4.4\;ng\;g^{-1}$) agrees well with the total selenium concentration measured with the ID method of $87.0{\pm}3.0\;ng\;g^{-1}$. Enzymatic hydrolysis of each selenium proteins revealed that SeCys is the major amino acid for all three proteins and SeMet is contained in SeAlb only.