• 전력전자학회논문지
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• 제17권4호
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• pp.353-358
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• 2012

In this paper, three-phase power equalizing system (PES) with UPS function is proposed. This system is based on NiMH battery with battery management system. The power conversion circuit is composed with the three-phase converter/inverter, the bi-directional converter, and the thyristor switches. The three-phase converter/inverter provides the power to the grid or get the power from the grid. Also, it operates as a UPS. The bi-directional converter charges or discharges the battery. The thyristor switches are used for connecting/disconnecting with the grid and the load. A 15 kW prototype is implemented for the verifying the performance of the proposed system.

• Journal of Biosystems Engineering
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• 제35권6호
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• pp.413-419
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• 2010

Plant growth was greatly affected by the spectral distribution and light intensity of artificial lighting sources. In this study, the spectral characteristics of high power sodium (HPS) lamps and metal halide (MH) lamps produced by three different manufacturers were measured. Even though the spectral distribution of HPS lamps with lamp wattage of 250 W and 400 W was very similar, but the spectral light intensity by the manufacturers was different. Difference in the spectral light intensity of MH lamps by the manufacturers was increased with the increasing lamps wattage. Light intensity at the region of blue (B), green (G), red (R) and far-red (FR) light of HPS and MH lamps was also analyzed. HPS lamps showed the light intensity in order of R, FR, B and G light. The ratio of G, B, R and FR to photosynthetic photon flux (PPF) of HPS lamps with the lamp wattage of 250 W was 3.0-3.2%, 5.5-5.9%, 17.3-19.2% and 6.5-7.8%, respectively. For MH lamps, it showed the light intensity in order of R, FR, B, and G. The ratio of B, G, R, and FR to PPF of MH lamps with 250 W was 14.0-15.5%, 22.6-27.5%, 7.5-9.5% and 2.7-4.2%, respectively. HPS and MH lamps with 400 W had a relatively smaller ratio of R and FR to PPF than those with 250 W. HPS lamps showed that the ratio of light intensity of B and FR to R was 0.15-0.28 and 0.36-0.4, respectively. For MH lamps, the ratio of light intensity of B and FR to R was 1.26-2.72 and 0.27-0.56, respectively. From these results, it was concluded that the portion of blue light of MH lamps was higher than those of HPS lamps.

• 생물환경조절학회지
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• 제17권2호
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• pp.132-137
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• 2008

동계 절화장미 'Vital'재배시 보광이 장미의 생육과 절화수량에 미치는 영향을 구명코자 하였다. 보광 광원은 250W의 메탈할라이드등, 고압나트륨등 및 혼합(메탈할라이드등+고압나트륨등)등을 베드 위 120cm 높이에 $310cm{\times}450cm$로 설치하였다. 보광등에서 1m 떨어진 지점의 광도는 $32{\sim}34{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$였다. 보광구는 무처리구에 비해 개화소요일수가 1번화는 $5{\sim}8$일, 2번화는 $3{\sim}5$일 단축되었다. 보광구 간에는 혼합등이 개화소요일수가 가장 짧았고, 고압나트륨등, 메탈할라이드등 순 이었으나 차이가 크지 않았다. 생육도 보광구가 무처리구에 비해 좋았다 특히 블라인드 발생이 $5{\sim}7%$ 감소되어 절화수량 증가의 주 요인이었다. 보광구간에는 혼합등이 가장 좋았고, 메탈할라이드등, 고압나트륨등 순 이었으나 큰 차이는 없었다 결론적으로, 보상점보다 낮은 광도의 보광도 개화소요일수 단축 및 블라인드 발생억제에 효과적이었다.

• 아동학회지
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• 제17권1호
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• pp.245-258
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• 1996

The purpose of this study was to examine the relationship between mother's parenting stress and child's temperament, mother's temperament, and poorness-of-fit. The subjects were 236 mothers of 4- to 6-year-old children in Seoul. Data was analyzed by correlation, analysis of variance, and stepwise regression analysis. Results showed that most poorness-of-fit of emotionality was due child's high-mother's high (CH-MH) and high-low (CH-ML) combination. Most poorness-of-fit (activity as well as sociability) was associated with child's low-mother's low (CL-ML) and low-high (CL-MH) combination. Mothers who had a highly emotional child and who were in poorness-of-fit emotionality perceived more hassles and more intensive daily parenting stress. It was also found that the most significant variable predicting mother's hassles and daily stress intensity was poorness-of-fit of emotionality, followed by mother's emotionality.

• Transactions on Electrical and Electronic Materials
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• 제17권2호
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• pp.79-85
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• 2016

In this study, we proposed a new single-stage small power MH lamp electronic ballast and power-factor correction circuit with improved circuit by the current of passive power factor correction. Main circuit integrates traditional DC/DC and DC/AC circuits into one-stage DC/AC inverter. Moreover, we described the working principle and control strategy of the new circuit; it's soft switching principle; and resonant element parameter design formula. An experimental prototype of HID lamp electronic ballast with output power of 70 W was built to verify the feasibility of the analysis and design. The simulation and experimental results proved that the power factor of this circuit could reach 94%, with efficiency of 90%. The input current harmonics conform to IEC 61000-3-2 standards and its cost is low. These superior performances of the new circuit indicate certain practical values.

• 소성∙가공
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• 제17권3호
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• pp.170-181
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• 2008

The shape of rectangular cup used for Ni-MH(Nickel-coated Metal Hydrogen) battery for hybrid car looks quite simple, but the forming process of extruding and setting up process design are highly difficult. Furthermore, there are few concrete reports on the rectangular deep drawn cup as part of hybrid vehicles till now. In this study, process design for rectangular cup in the multi-stage deep drawing process is carried out, and FE analysis is also preformed based on the result of the process design. From the simulation result, some unexpected problems such as earing, wrinkling and excessive thickness changes of the intermediate blank occurred. To overcome these failures, a series of modification for punch shape in the forming process design are completed and applied. Considering the modified punch shape in the multi-stage deep drawing process, additional FE analysis is also carried out and the simulation result is verified in view of the deformed shape, thickness change and effective strain distribution. The result of FE analysis with the improved process design confirmed not only reducing thinning of wall and possibilities of failure but also improving the quality of drawing product through the modification of punch shape.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제42권
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• pp.8.1-8.5
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• 2020

Background: The cause of maxillary growth restriction in patients with cleft lip and palate remains controversial. While studies have investigated the effects surgical technique and timing have on maxillary growth, few focus on patients with isolated cleft palate (ICP). The purpose of this study was to determine the impact palate repair and its associated complications may have on maxillary growth. Methods: A retrospective chart review of ICP patients who underwent palatoplasty from 1962 to 1999 at Akron Children's Hospital was performed. Patient demographics, Veau type, age at primary repair, closure technique, presence of fistula or velopharyngeal insufficiency (VPI), number of palatal operations, maxillary hypoplasia (MH) frequency, and follow-up were recorded. Exclusion criteria included patients with cleft lip, submucous cleft, or syndromes. Results: Twenty-nine non-syndromic ICP patients were identified; 62% (n = 18) had Veau type 1 and 38% (n = 11) had Veau type 2. All patients underwent 2-flap or Furlow palatoplasty with mobilization of mucoperiosteal flaps. Vomerine flaps were used in all Veau 2 cleft palate closures. Palatoplasty was performed at a mean age of 19.9 ± 8.2 months. Average follow-up was 209 ± 66.5 months. The rate of VPI was 59% (n = 17) and the rate of oronasal fistula was 14% (n = 4). Conclusions: There was a low incidence of MH despite complications after initial palate closure. Our results seem to suggest that age at palate closure, type of cleft palate, and type of surgical technique may not be associated with MH. Additionally, subsequent procedures and complications after primary palatoplasty such as VPI and palatal fistula may not restrict maxillary growth.

• 정보보호학회지
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• 제4권2호
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• pp.5-17
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• 1994

전자 우편 시스템은 컴퓨터와 네트워크를 이용하는 이용자들이 가장 빈번히 사용하고 있는 서비스 중의 하나로서 그 이용률은 매년 급증하고 있으며 이와 더불어 교류되는 정보에 대한 보호 및 안전성에 대한 요구도 제기되고 있다. 본 고에서는 이러한 전자 우편 시스템에 보호 서비스를 제공하기 위한 여러 제안된 방식들중에 X.400 MHS과 Internet의 PEM(Privacy Enhanced Mail),미국의 SDNS MSP(Message Secure Protocol)에 관하여 각각의 보호 서비스 제공 방식과 보호 서비스의 유형, 범위, 특성들을 논의하며 이들 접근 방식간의 관련성과 차이점들을 분석하고자 한다.

• 한국농공학회지
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• 제17권1호
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• pp.3685-3701
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• 1975

This study was conducted to investigate the strength of soil cements for varied molding water content and cement content(3,6,9,12%) in four cementstabilized soils(KY: sand, MH: sad, SS: sandy loam, JJ: loam). The eoperimental results obtainedfrom unconfined compressive strength tests are asfollows: 1. The optimum moisture content increased in accordance with the increase of the cement while maximum dry density didn't change uniformly. 2. The moisture content for maximum strength was higher than the optimum moisture content in the higher cement content. Moisture-density curves showed a dull peak in the higher cement contents, on the other hand, a sharp peak in the lower cement contents. 3. In molding the specimen with the approximate optimum moisture content, the maximum strength showed at the wet side of the optimum moisture content. 4. SS and JJ maybe used as cement-stabilized base of road to require 300PSI of compressive strength cured seven days, but MH and KY may be not adequate. 5. In soil cement, the better the grain size distribution was, the stronger the compressive strength was itn general. 6. The relation between 28-day strengh and 7-day strength in the cementstabilized four soils may be expressed as follows: q28=1.55q7+1.5 in which q28:28-day strength. q7:7-day strength.

• 공업화학
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• 제17권1호
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• pp.62-66
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• 2006

본 연구에서는 폐 알루미늄을 이용하여 제조한 환경친화형인 발포 알루미늄 기능성 판넬의 특성을 조사하였고, 증점 공정, 교반 혼합 공정, 발포 공정, 냉각 공정을 거쳐 첨색 공정에 의한 제품 품질의 고급화를 추구하였다. 시험은 크게 세 가지로 구분하여 음향투과 손실 시험, 흡음율 측정 시험, 그리고 발포작업조건 및 스크랩 혼합시험을 시행하였다. 그 결과 폐 알루미늄을 이용해 만든 기능성 판넬은 초경량성이며 방음과 차음, 유해전자파 차폐에 탁월하고 약 $2.2kcal/mh^{\circ}C$ 정도로 낮은 열전도율 및 뛰어난 단열효과를 보이는 것으로 나타났다.