• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.4
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• pp.640-644
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• 1998

We have fabricated Sb/SiC(4H) Schottky barrier diode (SBD) of which characteristics compared with that of Ti/SiC(4H) SBD. The donor concentration of the n-type SiC(4H) obtained by capacitance-voltage (C-V) measurement was about $2.5{\times}10 ^{17}{\textrm}cm^{-3}$. The ideality factors of 1.31 was obtained from the slope of forward current-voltage (I-V) characteristics of Sb/SiC(4H) SBD at low current density. The breakdown field of Sb/SiC(4H) SBD under the reverse bias voltage was about $4.4{\times}10^2V$/cm. The built-in potential and the Schottky barrier height (SBH) of Sb/SiC(4H) SBD were 1.70V and 1.82V, respectively, which were determined by the analysis of C-V characteristics. The Sb/SiC(4H) SBH of 1.82V was higher than Ti/SiC(4H) SBH of 0.91V. However, the current density and reverse breakdown field of Sb/SiC(4H) were low as compared with those of Ti/SiC(4H). The Sb/SiC(4H), as well as the Ti/SiC(4H), can be utilized as the Shottky barrier contact for the high-power electronic device.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.7
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• pp.824-831
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• 2009

In order to investigate the quality characteristics of powdered teas using Compositae species flower, the samples of Chrysanthemum indicum L. (CI), Chrysanthemum boreale Makino (CB), and Chrysanthemum zawadskii var. latilobum (Maxim.) Kitam (CZ) were extracted with hot water and concentrated, and then mixed with different forming agents of dextrin (D) and maltodextrin (MD). The mixing ratio of D and MD was ranged from 9:1 (DMD91) to 8:2 (DMD82) or D and MD only. The solubility of the powdered tea was higher in added dextrin. The highest total polyphenol and flavonoid content of the powdered tea were 6.75 and 3.24 mg/g at CBDMD91, respectively. Total antioxidant activities of C. indicum, C. boreale, and C. zawadskii powdered tea ranged at $2.51{\sim}2.63$, $4.37{\sim}4.50$, and $3.44{\sim}3.55\;mg$ AA eq/g, respectively. In sensory evaluation, the C. indicum and C. zawadskii powdered teas obtained higher sensory score of all evaluation items than C. boreale powdered tea. The optimal mixing ratio at 36% of D and 4% of MD in forming agent was selected to enhance the sensory characteristics and antioxidant activities of powdered tea.

• Development and Reproduction
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• v.11 no.1
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• pp.31-41
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• 2007

The spermiogenesis of Crocidura shantungensis were studied by electron microscope. All process of spermiogenesis was divided into 11 phases 15 steps, based on the morphological features of the nucleus and cell organelles in cytoplasm of spermatids. The spermatids in Golgi and cap phases were a spherical shape. On the other hand, at the early acrosomal phase they changed into an oval shape, and the tail was created in this phase. In maturation phase, the shapes of spermatid head were thin and longish. Until step 7 the direction of spermatids head turned toward the lumen of the seminiferous tubule. From step 8 to step 15 their heads turned toward the basal lamina. In step 12, the nucleus and acrosome shown maximal elongation. From Step 13 the nucleus of spermatids became flat, simultaneously with flat expansion of the acrosome expanded, and the visible whole lengths of spermatids were tend to be shorten. Spermatid heading which arrived to step 14 was taken the final shape. The nucleus was doing the wedge shape, and the nuclear chromatins condensed completely and homogenized. In the spermiation phase, the spermatids were gradually disconnected from the cytoplasm of the Sertoli cell. In this phase, the acrosome of the spermatids were fully shorten and flat, and the spermatozoa completed the process of heading and the tailing. Considering all the results, the spermiogenesis may be useful information to analyze the differentiation of spermatogenic cells.

• Food Science and Preservation
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• v.15 no.6
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• pp.832-839
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• 2008

The stock that is the first step for preparation of soups and purees links to the taste of food. Many types of vegetable have been used in stocks, but this study focused on stocks prepared with sweet pumpkin. The stock preparation conditions including the weight of sweet pumpkin, the water volume, and the boiling time at $97^{\circ}C$ were optimized by response surface methodology. The quality characteristics of the resulting stock were investigated. The color, flavor, taste and overall acceptability were dependent parameters. A model equation was proposed with regard to the sweet pumpkin weight, water volume, and boiling time at $97^{\circ}C$. A sweet pumpkin weight of 357.9 to 403.0 g, a water volume of 689.8 to 768.5 mL, and a boiling time of 9.9 to 10.3 min at $97^{\circ}C$ were found to be the optimal stock preparation conditions. The quality characteristics of the sweet pumpkin stock prepared under the optimized conditions were pH 6.64, total acidity 0.18%, soluble solids $2.39\;^{\circ}Brix$, color value (L, 99.07 a, -2.43 b, 11.82), total polyphenol 280.75 mg/L, and electron donating ability 21.32%.

• Journal of Broadcast Engineering
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• v.12 no.1 s.34
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• pp.11-27
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• 2007

T-DMB(Terrestrial-Digital Multimedia Broadcasting) for portable and mobile broadcasting service was officially launched in the metropolitan area of Korea in December 2005. The development of interactive data services and the expansion of T-DMB network have been now progressed, and the regional T-DMB broadcasters will be selected in the near future. Although it is important to evaluate service area and reduce a fringe area for optimizing RF coverage of T-DMB, there was no professional system to support those works, and therefore lots of resources in budget, manpower and time were required. The measurement considering characteristics of SFN(Single Frequency Network) is essential in the implementation of T-DMB network which needs to control synchronization, spacing and output power of transmitters. In addition, mobile measurement, enough measured parameters for many-sided analysis of reception quality, efficient management of enormous measured data and representation of measured results on the electronic map are also important in evaluating service area. In this paper, we derived requirements for a new measurement system in T-DMB by considering the above details, and we proposed and developed an integrated measurement and analysis system. The developed system was applied to the implementation of T-DMB network of KBS and field tests, and it proved its efficiency and accuracy in result.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.59-63
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• 2005

가. 자율주행 트랙터가 작업하는 동안 작동상태를 효과적으로 모니터링하고 제어할 수 있도록 하기 위해 인터넷을 통한 자율주행 트랙터의 모니터링과 원격제어 기술에 대하여 시험 하였다. 나. 트랙터를 모니터링하고 제어하는 곳과 경작지가 있는 곳을 인터넷으로 연결하고, 운전자가 탑승하지 않은 트랙터는 인터넷을 통해 전달받은 명령을 수행하도록 액튜에이터를 제어하고 제어되는 상황을 경작지에 위치한 카메라가 촬영하여 인터넷을 통하여 원격지의 운전자 쪽으로 전송하도록 시스템을 구성했다. 다. HST 트랙터 조종장치로서 서보제어가 가능한 액튜에이터를 개발 장착하고 제어성능을 시험하였다. 전자유압제어(EHPS)식 조향액튜에이터는 , 조향가능각 100도의 전범위에 조향 제어가 가능했으며 전조향에 필요한 시간은 약 1.6초 정도 였다. 피스톤 펌프의 사판각을 제어하는 전후진 제어기는 리니어 모터 구동식으로 총 제어 변위 50mm를 이동하는데 제어시간이 약 1.2초 소요되었다. 엔진 회전수를 제어하기위한 스로틀 액튜에이터는 리니어 모터 구동식으로 제어변위 30mm에 대해 제어시간이 0.8초 소요되었다. 3점 링크에 부착된 작업기의 위치를 제어하는 리프트 제어기도 리니어모터로 구동하였으며 제어거리 40mm에 대해 제어시간 0.9초정도가 소요되었다 라. 제작된 HST 무인 트랙터를 인터넷과 무선통신 시스템을 이용하여 원격 모니터링과제어 가능성에 대해 시험 했다. 인터넷을 통한 장거리 원격제어 및 모니터링 시험에서 제어신호의 전달지연은 0.3 ${\sim}$ 0.5초정도로 제어신호의 피이드 백을 확인할 때까지는 약1초정도의 대기 시간이 필요한 것으로 나타나 모니터링 및 제어 시스템의 개발 시 이를 고려할 설계가 필요한 것으로 나타났다.된 표층수온 분포값보다 2005년 2월에 관측된 표층수온 분포값이 상대적으로 낮은 분포 특성을 나타내고 있었다. 따라서 인공위성자료를 이용한 황해의 2004년 해황 분석 결과는 이상수온 상승의 원인이 쿠로시오 해류의 변동과 관련성이 높다고 판단되며 이에 대한 지속적인 연구가 현재 진행중에 있다.에 인산염 처리, 여기에 초음파 처리, 마지막 단계로 3분 끓이면 억제율이 68%까지 억제되었다. 이는 단일처리시 전혀 억제를 못하는 처리를 단계별로 한 단계씩 더해가면 allergy 억제효과가 나타난다고 할 수 있겠다. 초음파 처리도 역시 저 allergy 처리 공정에 이용될 수 있는데 이것은 그 처리로 인해 새로운 알러젠이 생성될 수도 있다. 또한 복합처리로 allergy를 감소시키면 연속적이고 동시적으로 하기 때문에 원가를 절감할 수 있다.환경현안에 대한 정치경제적 접근을 외면하지 말고 교과서 저작의 소재로 삼을 수 있어야 하며, 이는 '환경관리주의'와 '녹색소비'에 머물러 있는 '환경 지식교육'과 실천을 한단계 진전시키는 작업으로 이어질 것이다. 이후 10년의 환경교육은 바로 '생태적 합리성'과 '환경정의'라는 두 '화두'에 터하여 세워져야 한다.배액에서 약해를 보였으나, 25% 야자지방산의 경우 50 ${\sim}$ 100배액 어디에서도 액해를 보이지 않았다. 별도로 적용한 시험에서, 토마토의 경우에도 25% 야자지방산 비누 50 ${\sim}$ 100배액 모두 약해를 발생하지 않았으나, 오이에서는 25% 야자지방산 비누 100배액에도 약해를 나타내었다. 12. 이상의 결과, 천연지방산을 이용하여 유기농업에 허용되는 각종의 살충비누를 제조할 수 있었으며, 방제가 조사결과 진딧물, 응애 등 껍질이 연약한

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.71-76
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• 2008

Purpose: A simple and efficient method to prepare nanocrystalline ZnO thin film with pure strong UV emission on soda-lime-silica glass substrates by low-temperature annealing was improved. Methods: Crystal structural, surface morphological, and optical characteristics of nanocrystalline ZnO thin films deposited on soda-lime-silica glass substrates by prefiring final annealing process at 300$^{\circ}C$ were investigated by using X-ray diffraction analysis, field emission-scanning electron microscope, scanning probe microscope, ultraviolet-visible-near infrared spectrophotometer, and photoluminescence. Results: Highly c-axis-oriented ZnO films were obtained by prefiring at 300$^{\circ}C$. A high transmittance in the visible spectra range and clear absorption edge in the ultra violet range of the film was observed. The PL spectrum of ZnO thin film with a deep near band edge emission was observed while the defect-related broad green emission was nearly quenched. Conclusions: Our work will be possibly adopted to cheaply and easily fabricate ZnO-based optoelectronic devices at low temperature, below 300$^{\circ}C$, in the future.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.377-383
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• 2019

Naval ships that are navigating always have the possibility of colliding, but there is no clear maneuvering procedure for collision avoidance, and there is a tendency to depend entirely on the intuitive judgment of the Officer Of Watch (OOW). In this study, we conducted a questionnaire survey when and how to avoid collision for the OOW in a Constant Bearing, Decreasing Range (CBDR) situation wherein the naval ships encountered obstacles. Using the results of the questionnaire survey, we analyzed the CBDR situation of encountering obstacles, and how to avoid collision in day/night. The most difficult to maneuver areas were Pyeongtaek, Mokpo, and occurred mainly in narrow channels. The frequency appeared on average about once every four hours, and there were more of a large number of ships encountering situations than the 1:1 situation. The method of check of collision course confirmation was more reliable with the eye confirmation results, and priority was given to distance at closest point of approach (DCPA) and time at closest point of approach (TCPA). There was not a difference in DCPA between the give-way ship and stand-on ship, but a difference between day and night. Also, most navigators prefer to use maneuvering & shifting when avoiding collisions, and steering is 10-15°, shifting ±5knots, and the drift course was direction added stern of the obstacles to the direction of it. These results will facilitate in providing officers with standards for collision avoidance, and also apply to the development of AI and big data based unmanned ship collision avoidance algorithms.

• Food Science and Preservation
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• v.23 no.3
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• pp.347-354
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• 2016

To investigate the effect of different acetic acid bacteria on qualities of detoxified Rhus verniciflua vinegar (DRV), different DRVs were produced by using three acetic acid bacterial strains including Acetobacter pasteurianus KACC16934 (AP), Acetobacter malorum V5-7 (AM), and Gluconoacetobacter entanii RDAF-S (GE). Little difference in pH (2.87~2.90) or titratable acidity (5.33~5.68%) was observed among different DRVs. Acetic acid yields of the AP, AM, and GE strains were 78.6%, 85.3%, and 85.9%, respectively. Organic acid content in different DRVs was in the range of 69.84~73.83 mg/mL. Oxalic acid, malic acid, succinic acid, acetic acid, and fumaric acid were detected in all DRVs. And glutamic acid, alanine, valine, leucine, tyrosine, lysine, anserine, and arginine were detected in all DRVs. Arginine and alanine were the predominant amino acids in all DRVs. PCA plots of electronic nose analysis data showed a significant differentiation of DRVs from different acetic acid bacterial strains. A sensory evaluation of all DRVs indicated that DRV fermented using AM was superior in the aspect of flavor, tasted and overall preference.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.5
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• pp.647-652
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• 2008

Quality characteristics of Chrysanthemum indicum L. flower tea were investigated with the number of pan-firing. Total nitrogen, tannin and caffeine contents of tea were increased as the number of pan-firing increased, whereas chlorophyll and total amino acid (AA) contents were decreased. TAA content was in the range of $5,226{\sim}6,561mg%$ with the number of pan-firing. The content of caffeine and chlorophyll was not changed with the number of pan-firing. As the number of pan-firing increased, total polyphenol, flavonoid content, and antioxidant activity was also increased. The highest total polyphenol and flavonoid content was 17.44 and 11.09 mg/g at 7 times pan-firing, respectively. Total antioxidant activity was the highest value of 16.45 mg AA eq/g at 7 times of pan-firing. Based on the sensory evaluation, the best overall quality of the tea was obtained with 5 times of pan-firing.