• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.148-148
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• 1999

다이아몬드에 버금가는 높은 경도뿐만 아니라 높은 화학적 안정성 및 열전도성 등 우수한 물리화학적 특성을 가진 입방정 질화붕소(cubic Boron Nitride)는 마찰.마모, 전자, 광학 등의 여러 분야에서의 산업적 응용이 크게 기대되는 자료이다. 특히 탄화물형성원소에 대해 안정하여 철계금속의 가공을 위한 공구재료로의 응용 또한 기대되는 재료이다. 특히 탄화물형성원소에 대해 안정하여 철계금속의 가공을 위한 공구재료로의 응용 또한 크게 기대된다. 이 때문에 각종의 PVD, CVD 공정을 이용하여 c-BN 박막의 합성에 대한 연구가 광범위하게 진행되어 많은 성공사례들이 보고되고 있다. 그러나 이러한 c-BN 박막의 유용성에도 불구하고 아직 실제적인 응용이 이루어지지 못한 것은 증착직후 급격한 박리현상을 보이는 c-BN 박막의 밀착력문제때문이다. 본 연구에서는 평행자기장을 부가한 ME-ARE(Magnetically Enhanced Activated Reactive Evaporation)법을 이용하여 c-BN 박막을 합성하고, 합성된 c-BN 박막의 밀착력에 미치는 공정인자의 영향을 규명하여, 급격한 박리현상을 보이는 c-BN 박막의 밀착력 향상을 위한 최적 공정을 도출하고자 하였다. BN 박막 합성은 전자총에 의해 증발된 보론과 (질소+아르곤) 플라즈마의 활성화반응증착(activated reactive evaporation)에 의해 이루어졌다. 기존의 ARE장치와 달리 열음극(hot cathode)과 양극(anode)사이에 평행자기장을 부여하여 플라즈마를 증대시켜 반응효율을 높혔다. 합성실험용 모재로는 p-type으로 도핑된 (100) Si웨이퍼를 30$\times$40 mm크기로 절단 후, 100%로 희석된 완충불산용액에 10분간 침적하여 표면의 산화층을 제거한후 사용하였다. c-BN 박막을 얻기 위한 주요공정변수는 기판바이어스 전압, discharge 전류, Ar/N가스유량비이었다. 증착공정 인자들을 변화시켜 다양한 조건에서 c-BN 박막의 합성하여 밀착력 변화를 조사하였다. 합성된 박막의 결정성 분석을 FTIR을 이용하였으며, Bn 박막의 상 및 미세구조관찰을 위해 투과전자현미경(TEM;Philips EM400T) 분석을 병행하였고, 박막의 기계적 물성 평가를 위해 미소경도를 측정하였다. 증착된 c-BN 박막은 3~10 GPa의 큰 잔류응력으로 인해 증착직후 급격한 박리현상을 보였다. 이의 개선을 위해 증착중 기판바이어스 제어 및 후열처리를 통해 밀착력을 수~수백배 향상시킬 수 있었다. c-BN 박막의 합성을 위해서는 증착중인 박막표면으로 큰 에너지를 갖는 이온의 충돌이 필요하기 때문에 기판 바이어스가 요구되는데, c-BN의 합성단계를 핵생성 단계와 성장 단계로 구분하여 인가한 기판바이어스를 달리하였다. 이 결과 그림 1에서 나타낸 것처럼 c-BN 박막의 핵생성에 필요한 기판바이어스의 50% 정도만을 인가하였을 때 잔류응력은 크게 경감되었으며, 밀착력이 크게 향상되었다.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.351-356
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• 2007

The objective of this study was to develop a rapid and reliable method for the sex determination of beef using the PCR(polymerase chain reaction) technique. We have used two bovine sex determining genes, SRY and ZFY, on the Y-chromosome to identify the sex of Hanwoo and Holstein beet. We attempted to amplify 1,348 bp and 979 bp fragments from male and female genomic DNA corresponding to the SRY and ZFY genes, respectively, using male specific primers. The amplified PCR products were separated by electrophoresis in a 1.5% agarose gel to detect a male specific DNA band. When DNA from male beef was amplified with primers specific for the SRY gene, a DNA band of 1,348 bp was present in all of the male samples, but absent from all of the female samples. Also, when DNA from male beef was amplified with primers specific for the ZFY gene, a DNA band of 979 bp was observed in all of the male samples, but absent from all female samples. In conclusion, the bovine SRY and ZFY genes are typically found only in male beef. For the practical application of this method for the sexing of commercial beef at the processing and marketing stages after slaughter. a total of 350 beef samples collected randomly from local markets were analyzed for sex determination. The proportions of male and female samples were 252 (72%) and 98 (28%), respectively. Therefore. the SRY and ZFY genes. which are specific for the Y-chromosome, may be useful sex-diagnostic DNA markers to distinguish male meat from female meat.

• Journal of the Korean Applied Science and Technology
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• v.35 no.2
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• pp.367-377
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• 2018

Swimming crab(Ovalipes punctatus) is produced in Korea and utilized as semi-processed food at streamed cooked state. Recently, protein hydrolysates have been known as having function such as antioxidant, suppression of hypertension, immunodulatory, alleviation of pain, and antimicrobial activity. This research was investigated to find the functional antioxidant from crab hydrolysates. To fine optimal protease enzyme, alcalase, bromelain, flavourzyme, neutrase, papain, and protamex were selected to evaluate the DPPH radical scavenging activity and finally bromelain to show the best activity was selected. The molecular weight of bromelain hydrolysates were distributed with range from 500 to 3,200 Da and 7 different molecules or more. The amino acids related to antioxidant capacity was about 42.54%. The processes optimization study used was the response surface methodology. The ranges of processes were the reaction temperature of 40 to $60^{\circ}C$, pH 6 to 8, and enzyme concentration 1 to 3%(w/v). As a result, the optimization of process was determined at temperature of $55^{\circ}C$, pH of 6.5, and enzyme concentration of 3%(w/v). In these conditions, degree of hydrolysates were maximum 71.60%. Therefore, we expect that those products are useful as functional food ingredients.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.42-47
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• 2017

In this study,we conducted an injection molding analysis of metal powder materials for the development of flanges, which are necessary adapters for optical communication. The metal powder injection molding process is a technique for producing an injection molded article having a complicated shape by mixing ceramic or stainless powder and binders. It is used to produce products which require complex processing technology or for which the productivity is low. The purpose of this study is to minimize the manufacturing processing of products which are manufactured through existing mechanical processing procedures. For the injection molding analysis, we mixed stainless STS316 metal powder with binders at a ratio of 6 to 4 to make molding materials consisting of granular pellets. Then, three-dimensional modeling and meshing were carried out to obtain the optimal injection molding analysis conditions(molding temperature, melting temperature, injection time, injection temperature, injection pressure, packing time and cooling time). As a result of the analysis, it was discovered that the inlet became available 13.29 seconds after the first injection. Also, as the flowing and packing in the melt through the sprue, runner and gate were stable, it is expected that good molds can be manufactured.

• Analytical Science and Technology
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• v.23 no.3
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• pp.312-321
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• 2010

Seven indicator PCBs (IUPAC nos 28, 52, 101, 118, 138, 153, 180 congeners) concentrations were measured in food samples including cereal (polished rice), meats, eggs, milk and dairy products, and fisheries and products as representation for the general Korean populations during 2006-2007, and was analyzed using isotopic dilution method. Fishes had the highest average level as 39.8 ng/g, 1.4 ng/g for milk and dairy products, and 0.9 ng/g for meats. The hairtail out of fishes was contaminated at the level of 15.4 ng/g, 5.4 ng/g for pacific mackerel and spanish mackerel, and 4.5 ng/g for yellow croaker. The ratio for indicator PCBs in overall food was contributed as follows; 35.8% for PCB-153, 16.2% for PCB-138, 16.1% for PCB-101, 13.4% for PCB-118, 8.8% for PCB-180, 6.9% for PCB-52, and 2.9% for PCB-28. The hexa-CBs including PCB-153 and 138 were more predominated, and the next was penta-CBs including PCB-101 and 118 in food. For estimated daily intake (EDI) in average and $95^{th}$ percentile, fishes and products out of overall food were taken to represent over 50%. However, it was estimated that there was no adverse health effect for Korean.

• Korean Journal of Food Science and Technology
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• v.50 no.2
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• pp.132-137
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• 2018

Enzymatic treatments of maize flour (MF) were investigated using commercial carbohydrases (Ultraflo L and Pentopan 500 BG) to enhance the phenolic acid content and antioxidant property. The total phenolic acid content of the MF was 3.76 mg/100 g, whereas those of the Pentopan 500 BG and Ultraflo L treated MF were 6.85 and 39.55 mg/100 g, respectively. Particularly, ferulic acid content of Pentopan 500 BG-treated MF was 20.0 times higher than that of untreated MF (1.7 vs. 33.9 mg/100 g). Pentopan 500 BG appeared to be more effective than Ultraflo L in increasing the free phenolic acid content. Antioxidant activities of enzyme treated MF were significantly higher than untreated MF. In particular, the Pentopan 500 BG-treated MF (16.0 mmol TE/100 g) was approximately 1.5 times higher than untreated MF (12.6 mmol TE/100 g). Enzymatic hydrolysis of cell wall polysaccharides in MF could be used as an effective procedure for not only increasing phenolic content but also antioxidant activities.

• Journal of the Korean Society of Food Culture
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• v.5 no.3
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• pp.349-359
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• 1990

This study was carried out to understand and analyze the cooking and processing methods presented in CHE MIN YO SUL, Chinese books of husbandary was written in sixth century. This book was composed of two parts-part I is Agricultural production and part II is product-Utilization. Especially, wines and yeast(NU RUK) written in part II were studied at this study paper. Most of yeast was made of barley and wheat. These materials had been prepared as raw, steamed, and roasted state by proper ratio with kinds of yeast and then fermented as dough state. Occasionally, various kinds of soup made from cocklebur, leaves of mulberry tree, wormwood etc. put into yeast dough. Yeast doughs were shaped round and square with or without hole in the center, made in July of the lunar calendar and fermented for 3 or 4 weeks. There were 43 kinds of wines in this book. Most of them were made of all kinds of cereals grown at that time-rice, waxy rice, millet, waxy millet etc. These cereals had been steaming or cooking gruel with grain or powder state and then fermented with yeast. These wines were prepared by single or double brewing methods and the kinds of double brewing wines were more than single brewing wines by two times. There were none of wines made from fruit and distilled wines. Generally, single brewing wines were not made in Apr., Nov., Dec., of the lunar calendar and double brewing wines were not made in Aug., Oct., Nov., of the lunar calendar. And ripenning periods of wine brewing were various, from 1 day to 7 months for single brewing, from 2 days to 8 months for double brewing.

• Korean Journal of Food Science and Technology
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• v.47 no.4
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• pp.539-543
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• 2015

A hardy kiwifruit is a good source of phenolics and antioxidants. This study was aimed at investigating the effects of hot air drying at three different temperatures (35, 50, and $70^{\circ}C$) for 24 h on the total phenolic and flavonoid contents and the antioxidant capacity of hardy kiwifruits of Actinidia arguta ${\times}$ A. deliciosa cv. Mansoo. Dried kiwifruit extracts were produced using 80% (v/v) aqueous ethanol under homogenization. Hot air drying lowered the total phenolic and flavonoid contents and decreased the antioxidant capacity in the dried kiwifruits compared with their fresh counterparts. The results also revealed high positive linear correlations of antioxidant capacity with total phenolic and flavonoid contents, indicating that phenolics are the major contributors to antioxidant capacity. Our results suggested that an optimal drying process must be determined for industrial application in order to obtain dried kiwifruits with increased antioxidant capacity for consumers.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1121-1140
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• 1992

In metal cutting the shape of generated chip varies according to cutting conditions, characteristics of workpiece and geometry of cutting tool. The best surface roughness of machined workpiece is obtained when generating flow type contrinuous chip. If the generated chip is not broken, that is not only tangled workpiece and cutting tool, but also may give damage on the machined surface of workpiece or danger for a operator. The flow type continuous chip may bring the low productivity in high speed any heavy cutting, automatic machining process and non-human factory. There are two type of chip break process ; controlling cutting condition and using chip breaker. In present study we carried out the experiment on new type chip breaker compared with conventional type and proved the efficiency of a new type and showed the chip break condition to be applied in actual metal cutting. In the experiment SM 20 C as a workpiece material and WC as a tool material were used and cutting speed of 30-150m/min, feed of 0.071-0.210mm/rev and depth of cut of 1mm were applied as cutting condition. The results of the experiment are as follows : (1) The mechanism of chip curl can be explained more clearly by plastic flow of workpiece material and moment of shearing force. (2) The most effective radius of curled chip and flat distance from cutting edge is 2.0-2.5mm and 1.5mm in both types. (3) The effective inclination angle of chip break surface and side cutting edge angle are 30.deg.- 45.deg. and 20.deg. in conventional type, while the radius of arc surface, lower arc angle A, upper arc angle B and side cutting edge angle are 3mm, 20.deg.- 45.deg., 0.deg.- 45.deg. and 10.deg.- 20.deg. in new type. (4) The probability to be obtained 100% chip breaking ratio is much higher in new type than in conventional type.

• The Journal of the Korea Contents Association
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• v.15 no.2
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• pp.377-392
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• 2015

In today's data-driven society, we've been hearing a great deal about the power of Big Data over the last couple of years. At the same time, it has become the most important issue that the problems is caused by the data collection, management and utilization. Moreover, Big Data has a wide applications ranging from situation awareness, decision-making to the area to enable for the foreseeable future with man-made and analysis of data. It is necessary to process data into meaningful information given that the huge amount of structured and unstructured data being created in the private and the public sector, even in disaster management. This data should be public and private sector at the same time for the appropriate linkage analysis for effective disaster management. In this paper, we conducted a literature review and case study efficient Big Data to derive the revitalization of national disaster management. The study obtained data on the role and responsibility of the public sector and the private sector to leverage Big Data for promotion of national disaster management plan. Both public and private sectors should promote common development challenges related to the openness and sharing of Big Data, technology and expansion of infrastructure, legal and institutional maintenance. The implications of the finding were discussed.