• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 추계학술대회 논문집 전기물성,응용부문
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• pp.153-156
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• 2004

An electric power efficiency of electrodeless fluorescent lamp has big relative property of gas in lamp, gas pressure, lamp formation, ingredients of magnetic substance and shape and action frequency etc. We used magnetic substance that open self examination material of electrodeless fluorescent lamp antenna. Ferrite that is used in this experiment was Mn-Zn type. We have examined resistance kind, impedance, Q-factor's frequency characteristic by ferrite. Impedance, resistance and capacitance did not show difference in start frequency 2.65 [MHz] but there was difference quantity. We could know Q-factor's difference according to material, and Q-factor's is important part of antenna design.

• 한국항해학회지
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• 제20권4호
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• pp.129-137
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• 1996

In this paper, we simulated a radiation pattern directivity of microstrip patch antenna for 9[GHz] using the computer. It is analyzed and compared the directivity of field characteristics at two different aspects. One is that of 1-dimension and 2-dimension array, the other is that of a linear and planar array antenna. We tried the constants for the simulation of teflon substrate, dielectric constant ${\varepsilon}r=2.50$, ground plane conductor thickness t=0.03556, substrate height h=0.72188, dielectric loss degree $tan{\delta}$=0.00085, characteristics impedence of line $Zo=50({\Omega})$. The major advantage of microstrip patch antenna is that the arrangement of antenna is associated with the directivity and effectiveness. We have been studied the difference of the radiation pattern of antenna with wave variety through computer simulation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.809-811
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• 1993

The load impedance of power lines generally varies with time, areas, and season. Also, the harmonic noises by the power electrical equipments are scattered through the power lines. The received signal level varies with the environment and is not able to detect the PLC(Power Line Carrier) signal. For this reason, it is requried for the signal transmitter to hold the received signal level uniform independently with the variation of the load impedence. In this paper, the power lines are modeled simply and a method keeping the received signal level uniform is suggested through the analysis of the signal transmission characteritics of the PLC coupler using tank circuit.

• 지역사회간호학회지
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• 제9권2호
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• pp.458-466
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• 1998

The purpose of this study is to investigate the differences in body fat distribution between obese boys and girls in high school and the relationship between the precent of body fat and the Broca Index. The survey of data was conducted from November 3rd to the 11th in 1997. The data were analyzed by the use of a mean, standard deviation and a Pearson's correlation coefficient. Measurements of the percentage of body fat and lean body mass were made by a Bioelectrical Impedence while height, weigh and the Broca index were measured by a fatness measuring system. First, measurements of height, weight and the Broca index were made by a fatness measuring system on 1,125 1st year students and 1,076 2nd year students. The result of measurements, 216 obese boys and 100 obese girls appeared to have above 10% of the Broca index. The result of this study can be summarized as follows: 1) Obese boys and girls were grouped by the level of the Broca index as follows: boys, 110-less than 120 60.0%, 120-less than 130 20.8%, 130-less than 140 11.1%, above 140 7.4%. ; girls, 110-less than 120 44.4%, 120-less than 130 32.0%, 130-less than 140 13.0%, above 140 11.0%. 2) Obese boys and girls were grouped by level of the percentage of body fat by Bioelectrical Impedence as follows: boys, less than 20% 5%, 20%-less than 25% 34.7%, above 25% 33.8% ; girls. less than 25% 15.0%, 25%-less than 30% 43.0%, above 30% 42.0%. 3) In obese boys the Broca index score appeared to be positively related to body weight(r = .741, p<.001), the percent of body fat(r=.604, p<.001), lean body mass(r=.375, p<.001), body fluid(r=.445, p<.001l). On the other hand the percent of body fat was not a significant correlation of lean body mass (r= -.074), body fluid(r= -.073). 4) In obese girls, the Broca index score appeared to be positively related to body weight(r= .693, p<.001), the percent of body fat(r=.645, p<.001), lean body mass(r=.531, p<.001), body fluid(r=.532, p<.01), and the percent of body weight score appeared to be positively related to lean body mass(r=.206, p<.01), body fluid(r=.207, p<.01).

• Journal of Preventive Medicine and Public Health
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• 제43권6호
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• pp.479-485
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• 2010

Objectives: The Korean Genome and Epidemiology Study (KoGES), a multicenter-based multi-cohort study, has collected information on body composition using two different bioelectrical impedence analysis (BIA) machines. The aim of the study was to evaluate the possibility of whether the test values measured from different BIA machines can be integrated through statistical adjustment algorithm under excellent inter-rater reliability. Methods: We selected two centers to measure inter-rater reliability of the two BIA machines. We set up the two machines side by side and measured subjects' body compositions between October and December 2007. Duplicated test values of 848 subjects were collected. Pearson and intra-class correlation coefficients for inter-rater reliability were estimated using results from the two machines. To detect the feasibility for data integration, we constructed statistical compensation models using linear regression models with residual analysis and R-square values. Results: All correlation coefficients indicated excellent reliability except mineral mass. However, models using only duplicated body composition values for data integration were not feasible due to relatively low $R^2$ values of 0.8 for mineral mass and target weight. To integrate body composition data, models adjusted for four empirical variables that were age, sex, weight and height were most ideal (all $R^2$ > 0.9). Conclusions: The test values measured with the two BIA machines in the KoGES have excellent reliability for the nine body composition values. Based on reliability, values can be integrated through algorithmic statistical adjustment using regression equations that includes age, sex, weight, and height.

• 대한토목학회논문집
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• 제36권6호
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• pp.1083-1091
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• 2016

본 연구는 대중교통카드자료를 이용해서 수도권 지역간 대중교통통행에서 승객들이 겪는 환승시간, 환승회수의 환승저항을 분석한다. 현재 교통카드자료는 버스와 철도를 이용하는 수단통행을 5회까지 Trip Chian으로 기록하여 수단간 환승과 관련된 정보는 쉽게 파악된다. 그러나 수도권 교통카드는 도시철도의 통행에서 발생하는 환승역 정보를 포함하고 있지않아 Trip Chain에서 승객이 경험하는 환승저항이 저평가되는 문제가 존재한다. 따라서 철도통행에 대하여 승객행태를 반영하는 경로선택모형으로 구축하여 환승시간과 환승회수를 반영하면 온전한 환승저항의 설명력을 갖게된다. 연구방법으로서, 우선 수도권 대중교통환승에 대한 개념을 정립하여 도시철도가 포함되는 수단이용의 경우 교통카드자료의 환승저항 개념을 새롭게 정립한다. 또한 Trip Chain내에 철도의 경로선택모형을 구축하여 환승시간 및 환승회수를 대상으로 통행저항을 재평가하여 설정한다. 그리고 버스 및 도시철도 정류장 좌표를 행정동단위의 소죤 및 시군구 단위의 중죤으로 일치시키기 위해서 빅노드를 운영하는 방법을 채택한다. 마지막으로 수도권의 지역간 통행에서 철도수단이 한번 포함된 통행사슬에 대한 사례연구를 통하여 결과의 타당성을 논의한다.

• 농업과학연구
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• 제24권2호
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• pp.267-274
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• 1997

산채류를 비롯한 식물자원으로부터 항혈전 성분을 탐색하기 위하여 전국일원의 농산시장 및 농촌지도소, 평창산채시험장과 한국인삼연초연구원의 실험포장으로부터 약 160점의 시료를 수집하였으며, modified smear method를 적용하여 그 methanol 추출물의 혈소판응집 저해활성을 비교하였다. Platelet rich plasma 즉 혈소판 혈장을 이용하는 modified smear method는 응집유도물질로서 ADP와 collagen을 사용하였을때 electrical impedence method와 높은 상관성을 나타내었고, 재현성도 비교적 우수하여 정제하지 않은 식물체의 조추출물의 항혈전 활성을 효율적으로 검색할 수 있었다. 참취, 개미취, 곤달비, 산마늘, 산도라지, 영양부추, 산뽕, 쇠비름, 생열귀등이 ADP와 collagen 모두 혈소판응집 저해활성을 나타내었으며, 곰취, 사철쑥, 씀바귀, 민들레, 산지치, 갯완두, 참대등은 collagen을 사용한 경우에는 저해활성이 다소 낮게 검출되었다. 반면에 참나물, 옥잠, 냉이, 메밀, 매실, 복분자, 해란초등은 오히려 혈소판응집 촉진효과를 나타내었다. 한편 DPPH법으로 활성산소 억제율을 비교한 결과 산채류중에는 고사리, 참취, 곰취, 구절초, 사철쑥, 고려엉겅퀴, 달개비, 냉이 그리고 생약재중에서는 적작약, 음양곽, 복분자등이 항산화활성이 높았다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.89-93
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• 1991

The purpose of this reserch is to design the blood cell counting instrument which can measure the number of RBC(Red Blood Cell) and WBC(White Blood Cell) including many other blood component. The proposed method uses the electrical impedence method and the new discrimination method wi th DSP chip and software algorithm. The system consist of control unit, blood cell discrimination unit, hemoglobin spectrometer, post detect ion processor unit, and IBM-PC interface unit. In this paper, the discrimination system has been implemented using digital signal processor, which result in the reduction of system hardware and cost. The system is helpful in providing necessary clinical test for screen test and quality control of hematology.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.163.2-163.2
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• 2010

In this work, nano-flake shaped nickel oxide (NiO) films were synthesized by chemical bath deposition technique for electrochemical capacitors. The deposition was carried out for 1 and 2 h at room temperature using nickel foam as the substrate and the current collector. The structure and morphology of prepared NiO film were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). And, electrochemical properties were characterized by cyclic voltammetry, galvanostatic charge-discharge, and AC impedence measurement. It was found that the NiO film was constructed by many interconnected NiO nano-flakes which arranged vertically to the substrate, forming a net-like structure with large pores. The open macropores may facilitate the electrolyte penetration and ion migration, resulted in the utilization of nickel oxide due to the increased surface area for electrochemical reactions. Furthermore, it was found that the deposition onto nickel foam as substrate and curent collector led to decrease of the ion transfer resistance so that its specific capacitance of a NiO film had high value than NiO nano flake powder.

• 대한화학회지
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• 제58권5호
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• pp.437-444
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• 2014

변전위법과 전기화학적 임피던스측정법(electrochemical impedence spectroscopy)을 이용하여 borate 완충용액에서 Co-RDE의 전기화학적 부식과 부동화에 대하여 조사하였다. Tafel 기울기, 코발트 회전원판전극의 회전속도, 임피던스 그리고 부식전위와 부식전류의 pH 의존성으로부터 코발트의 부식과 부동화 반응 메커니즘과 환원반응에서의 수소 발생 반응구조를 제안하였다. EIS data로부터 등가회로를 제안하였으며 산화반응의 영역별로 전기화학적 변수들을 측정하였다. 부식전위에서 측정된 Nyquist plot의 induction loop가 낮은 주파수 영역에서 관측되는 것으로 보아 흡착/탈착 현상이 Co의 부식과정에 영향을 미치는 것으로 보인다.