• Journal of Community Nutrition
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• 제5권1호
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• pp.37-43
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• 2003

Iron deficiency and anemia are severe nutrition problems in most of Korea. Iron intake, especially iron with better bioavailability is insufficient over a total age group. Recent changes in diet and life style of Koreans have been repeatedly suggested problems caused by excess nutrient intake rather than under intake. Despite the changes in diet patterns, iron deficient anemia is still prevalent in many parts of Korea. Eight hundred and fifty subjects (323 male and 527 female subjects) in Asan were recruited from farming, factory and urban area. Each subject was interviewed to assess nutrients intakes according to a 24hr-recall method. Twelve hour fasting blood samples were collected to vacutainer with EDTA for hemoglobin (Hb) and separate the tubes for serum iron (SI) and total iron binding capacity (TIBC). The mean serum iron value of female subjects in the factory area was significantly higher (p < 0.05) than that of the female subjects in the urban area although subjects in urban area showed significantly higher the dietary iron intake for both the men and woman (p < 0.05). Dietary iron intake for the younger women was lowest in the farming area and those in the urban area showed the highest dietary iron intake (p < 0.05). When the dietary iron intake was compared by different the age groups, dietary iron intake of the older women from animal sources was less than that of younger women in the urban area (p < 0.05). Dietary iron intake of Asan residents was not sufficient regardless of age, sex and regions and intake of heme iron was especially lower than nonheme iron. (J Community Nutrition 5(1) : 37∼43, 2003)

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권2호
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• pp.45-50
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• 2004

The field utilization factor (equation omitted) (the mean electric field / the maximum electric field) of standard sphere gaps was calculated by the charge simulation method, taking into account the ground plane and shanks. n changes mainly with g/r and slightly with 1$_1$, 1$_2$ and 1, where D=2r is the sphere diameter, g is the gap length, 1$_1$ and 1$_2$, respectively, are the lengths of the upper and lower shank, and t is the shank diameter. Generally, (equation omitted) increases as 1$_1$,1$_2$ and t each becomes larger. IEC standard 60052(2002) limits t$\leq$0.2D 1$_1$$\geq$1D and prescribes A=1$_2$＋D＋g where A is the height of the spark point on the upper sphere. Therefore, (equation omitted) is the largest when A=9D and the smallest when A=3D. The simple equation of a straight line, (equation omitted)=1- (g/3r), can generally be used as a representative value of (equation omitted) for a wide variety of sphere diameters that are permitted by the IEC standard. The maximum electric field E$_{m}$ at sparkover of standard air gaps has also been calculated by the relation E$_{m}$=V/(equation omitted)g). E$_{m}$ describes a U-curve for g/r, up to the sphere diameter of 1 m. Moreover, for 1.5-m and 2-m diameters and especially .for negative polarity, sparkover voltages have been calculated by integration of the ionization index.index.

• 한국통신학회논문지
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• 제31권11B호
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• pp.997-1004
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• 2006

인터넷을 기반으로 하는 IT 눈부신 발전과 더불어 언제, 어디서나, 시간과 장소에 구애받지 않고 인터넷을 사용할 수 있도록 하는 사회적 요구가 구체화 되고 있다. 이러한 요구에 부응하고자 국내에서는 시속 200km이상의 빠른 속도로 이동 중에 있더라도 초고속인터넷이나 방송 서비스를 제공할 수 있는 위성광대역 인터넷 시스템기술을 개발하고 있다. 본 연구에서는 위와 같이 개발된 시스템을 국내 고속철도(KTX)에 적용하여 서비스를 제공할 때, 관련 시설투자에 대한 경제적 타당성을 검토하고i라 한다. 경제성 분석을 위해 현재 유럽에서 이미 제공되고 있는 고속철도 인터넷서비스를 조사하였고, 국내 고속철의 특성을 감안하여 필요시설과 장비를 구성하여 항목별 비용분석을 수행하였다. 해외 사례와 비행기 등의 다른 운송수단에서 예상하고 있는 수요 및 요금 수준에 근거하여 고속철도 인터넷서비스 매출을 시나리오별로 전망하였으며, 각 시나리오에서 계산된 비용과 매출로부터 순현재가와 수익률을 산정 하였다. 본 연구의 결과는 관련 기술 개발에 대한 경제적 타당성 여부를 판단하는데 활용될 수 있으며, 비용효과적인 서비스 설계 및 구현에 도움을 줄 수 있을 것으로 기대된다.

• 설비공학논문집
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• 제24권5호
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• pp.454-460
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• 2012

The purpose of the present work is to investigate the removal characteristics of positively charged filters for capturing negatively charged particles such as bacteria and virus in water. In order to reduce the pressure drop and increase the filtration efficiency, the filter media, modified by charge modifier having positive functional groups, is developed and evaluated. Improved liquid filters have been developed with the modified surface charge to capture and adsorb particles by electrokinetic interaction between the filter surface and particles contained in an aqueous liquid. The positively charged filter media is composed of glass fiber, cellulose and poly-ethylenimine resin for positively charging with the variation of volume ratio. The zeta potential value of the positively charged filter is +37.92 mV at the glass fiber and cellulose content ratio of 50 : 50 with resin content of 100%, while that of the PSL test particle is -23.5 mV at pH 7. The removal efficiency of the electro-positively charged filter is 98% for PSL particles of 0.11 ${\mu}m$, while that of the negatively charged filter is 7%. The positively charged filter media showed the potential to be an effective method for removing fine particles from the contaminated water for liquid filtration.

• Restorative Dentistry and Endodontics
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• 제37권3호
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• pp.136-141
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• 2012

Objectives: The maintenance of the healthy periodontal ligament cells of the root surface of donor tooth and intimate surface contact between the donor tooth and the recipient bone are the key factors for successful tooth transplantation. In order to achieve these purposes, a duplicated donor tooth model can be utilized to reduce the extra-oral time using the computer-aided rapid prototyping (CARP) technique. Materials and Methods: Briefly, a three-dimensional digital imaging and communication in medicine (DICOM) image with the real dimensions of the donor tooth was obtained from a computed tomography (CT), and a life-sized resin tooth model was fabricated. Dimensional errors between real tooth, 3D CT image model and CARP model were calculated. And extra-oral time was recorded during the autotransplantation of the teeth. Results: The average extra-oral time was 7 min 25 sec with the range of immediate to 25 min in cases which extra-oral root canal treatments were not performed while it was 9 min 15 sec when extra-oral root canal treatments were performed. The average radiographic distance between the root surface and the alveolar bone was 1.17 mm and 1.35 mm at mesial cervix and apex; they were 0.98 mm and 1.26 mm at the distal cervix and apex. When the dimensional errors between real tooth, 3D CT image model and CARP model were measured in cadavers, the average of absolute error was 0.291 mm between real teeth and CARP model. Conclusions: These data indicate that CARP may be of value in minimizing the extra-oral time and the gap between the donor tooth and the recipient alveolar bone in tooth transplantation.

• 제어로봇시스템학회논문지
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• 제9권11호
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• pp.874-882
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• 2003

The condition assessment of engineering systems has increased in importance because the manpower needed to operate and supervise various plants has been reduced. Especially, induction motors are at the core of most engineering processes, and there is an indispensable need to monitor their health and performance. So detection and diagnosis of motor faults is a base to improve efficiency of the industrial plant. In this paper, a model-based fault detection system is developed for induction motors, using steady state vibration signals. Early various fault detection systems using vibration signals are a trivial method and those methods are prone to have missed fault or false alarms. The suggested motor fault detection system was developed using a model-based reference value. The stationary signal had been extracted from the non-stationary signal using a data segmentation method. The signal processing method applied in this research is FFT. A reference model with spectra signal is developed and then the residuals of the vibration signal are generated. The ratio of RMS values of vibration residuals is proposed as a fault indicator for detecting faults. The developed fault detection system is tested on 800 hp motor and it is shown to be effective for detecting faults in the air-gap eccentricities and broken rotor bars. The suggested system is shown to be effective for reducing missed faults and false alarms. Moreover, the suggested system has advantages in the automation of fault detection algorithms in a random signal system, and the reference model is not complicated.

• Bulletin of the Korean Chemical Society
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• 제35권5호
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• pp.1485-1490
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• 2014

We have designed and developed a new ladder type tetrafused ${\pi}$-conjugated building block such as dihydroindolo[3,2-b]indole (DINI) and investigated its role as an electron rich unit. The photovoltaic properties of a new semiconducting ${\pi}$-conjugated polymer, poly[[5,10-bisoctyl-5,10-dihydroindolo[3,2-b]indole-[5,6- bis(octyloxy)-4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole]], represented by PDINI-OBTC8 are described. The new polymer PDINI-OBTC8 was synthesized in donor-acceptor (D-A) fashion, where fused ${\pi}$-conjugated tetracyclic DINI, and 5,6-bis(octyloxy)-4,7-di(thiophen-2-yl) benzo[c][1,2,5]thiadiazole (OBTC8) were employed as electron rich (donor) and electron deficient (acceptor) moieties, respectively. The conventional bulk heterojunction (BHJ) device structure ITO/PEDOT:PSS/PDINI-OBTC8:PCB71M/LiF/Al was utilized to fabricate polymer solar cells (PSCs), which comprises the blend of PDINI-OBTC8 and [6,6]-phenyl-$C_{71}$-butyric acid methyl ester ($PC_{71}BM$) in BHJ network. A BHJ PSC that contain PDINI-OBTC8 delivered power conversion efficiency (PCE) value of 1.68% with 1 vol% of 1,8-diidooctane (DIO) under the illumination of A.M 1.5G 100 $mW/cm^2$.

• 농업과학연구
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• 제38권2호
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• pp.325-330
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• 2011

In order to revive the ecological function of degraded rivers, a total restoration plan for riverbeds and riparians needs to be developed. Previous evaluations for rivers were mainly focused on the river's physical structures. Therefore, this research has developed indicators to evaluate a riparian restoration considering biodiversity. Through literature and previous cases review, 4 fields and 13 indicators are selected for the evaluation. Four fields are biodiversity, habitat diversity, connectivity and habitat functionality. In the biodiversity field, 4 indicators of the exuberant extent of herbaceous vegetation and their diversity, the exuberant extent of shrub and woody plants and their diversity, the number of plant communities and naturalized plants are included. Habitat diversity are comprised of 4 indicators of the longitudinal continuity of vegetation, the mixture of plant communities, the extent of plant type color fruit abundance and the distribution of vegetation. Connectivity includes 3 indicators of target distribution, the shore slope of low water channels and the extent of artificial embankment materials. Habitat functionality has 2 indicators of the status of food supply plants and the habitat functionality. The value weighting for the fields and indicators has been calculated based on the AHP(Analytic Hierarchy Process) method. 50 experts were surveyed with quantifiable questionnaire, among them 43 experts have more than 10 yesrs experiences in the nature restoration field. The selected and weighted indicators have been tested to the 12 sections in Gap stream located in Daejeon. In conclusion, the indicators are feasible and the selected indicators could be used to establish the direction and objectives of riparian restoration.

• 대한전자공학회논문지
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• 제11권6호
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• pp.1-15
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• 1974

본 연구는 탄성파 지연선에 이용되는 탄성표면파중에서 SH표면파 모우드에 대하여 이론적 해석을 하였으며 그 결과 전기-기계적 결합계수가 크며 또한 여전 매질내 깊이 방향으로 아주 작은 감쇠률을 갖고 표면을 따라 전파됨을 알았단. 예로서 PZT-4인 경우 에너지의 80%가 감쇠되는 깊이는 190파장이 된다. 또한 탄성표면파 지연선을 하나의 계단자강으로서 취급하여 삽입손실를 구하였으며 특히 SH표면파 모우드와 같이 전기-기계론 결합계수가 큰 경우는 인터디지탈 트랜스듀셔의 전극폭과 윤극간 간격 사이의 비에 따라 중심 주파수가 현저히 달라진다. 그리고 탄성파 지연선의 온도계수를 벌크파인 종파, 횡파에 대하여 구하였으며 LiTaO2 Z축방향 전파의 횡파는 지연시간의 온도계수가 5.4X10-6/℃로 아주 작아짐을 알았다. 또한 LiNbO3의 130°, 64° 로테이트 Y캇트, X전파의 탄성표면파의 온도계수가 이론치와 잘 일치함을 실험적으로 확인하였다.

• 한국인터넷방송통신학회논문지
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• 제15권4호
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• pp.211-215
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• 2015

본 논문은 폴디드 모노폴 구조를 이용하여 무선 HDMI 동글장치의 내장형 안테나를 제안하였다. 제안한 안테나는 2.4GHz와 5.8GHz이다. 안테나는 'F'형 구조를 이용하여 모노폴 폴디드 안테나 길이, 간격, 폭 그리고 반원의 반지름을 파라미터로 정하여 최적화 하였다. 안테나 파라미터 특성을 확인하기 위해 ANSYS사의 HFSS를 이용하였다. 안테나 제작은 유전상수가 4.4인 FR4 유전체 기판을 사용하였다. 안테나의 크기는 HDMI 동글 크기 $45{\times}20{\times}1mm$이고, 안테나 부분은 $5{\times}20mm$이다. 제작된 안테나는 2.4GHz와 5.8GHz에서 반사손실이 -10dB를 만족하였다. 최대 안테나 이득은 -4.13dBi 임을 확인 할 수 있었다. 안테나의 측정결과와 시뮬레이션 결과를 비교하여 분석한 결과, 반원을 이용한 프린티드 폴디드 모노폴 안테나의 실용화 가능성을 확인할 수 있었다.