• 대한한의학회지
• /
• 제33권1호
• /
• pp.68-78
• /
• 2012

Objectives: The purpose of this study was to analyze the relationship between Yin-deficiency questionnaire score and various biofunctional signals in women. Methods: A retrospective chart review was performed on charts of 195 patients who visited Gangdong Kyung Hee Hospital between April 1st and September 30th, 2011. The subjects were categorized into two groups, a low Yin-deficiency group (n=118) and a high Yin-deficiency group (n=77). The authors analyzed the correlation between Yin-deficiency questionnaire score and biofunctional signals by Pearson's correlation coefficient test and the difference in biofunctional signals between the two groups by independent samples t-test using SPSS for windows. Results: 1. Negative correlations were observed between the temperature difference of back-humerus, standard deviation of all R-R intervals (SDNN), total power (TP), low frequency (LF), high frequency (HF) on heart rate variability parameters, and Yin-deficiency questionnaire score. A positive correlation was observed between the temperature difference of knee-humerus and Yin-deficiency questionnaire score. 2. The temperature difference of back-humerus in the high Yin-deficiency group was significantly higher than that in the low Yin-deficiency group. The temperature difference of knee-humerus, height, waist-hip ratio, SDNN, TP, LF, and HF of the high Yin-deficiency group were significantly lower than those of the low Yin-deficiency group. Conclusions: The results of this study suggest that the comprehensive diagnosis of Yin-deficiency and biofunctional signals is useful.

• 대한전자공학회논문지TE
• /
• 제39권4호
• /
• pp.409-412
• /
• 2002

IMT-2000 전 대역(1920∼2170MHz, BW=250MHz)에서 사용되는 중계기용 2단 저잡음 증폭기를 설계하였다. Ansoft사의 Serenade를 이용하여 첫째 단 PHEMT의 소스와 접지간 source lead의 인덕턴스 값을 최적화하여 기판 선고로 등가화하고, 첫째 단의 잡음 정합은 물론 각 단의 정합회로가 간단하도록 high pass 구조로 설계하였다. 바이어스 회로는 단일 능동회로로 구성하였고, 인가전압은 8V, 총 전류는 180mA이다. 이때, 첫째 단 PHEMT의 Vgs = -0.4V, Vds = 4V이고, 둘째 단 AH1의 Vds = 5V이다. 상업화가 가능하도록 설계 기준을 정하여 제작되었고, 측정 결과 이득은 20dB, NF는 1dB, 입력 VSWR은 1.14∼l.3dB, P1dB는 22.4dBm, gain flatness는 ±0.45dB로 상업용 저잡음 증폭기로 사용될 수 있다.

• Journal of Electrochemical Science and Technology
• /
• 제11권4호
• /
• pp.384-391
• /
• 2020

Due to its characteristics of light weight, high energy density, good safety, long service life, no memory effect, and environmental friendliness, lithium-ion batteries (LIBs) are widely used in various portable electronic products. The capacity and performance of LIBs largely depend on the performance of electrode materials. Therefore, the development of better positive and negative materials is the focus of current research. The application of metal organic framework materials (MOFs) derivatives in energy storage has attracted much attention and research. Using MOFs as precursors, porous metal oxides and porous carbon materials with controllable structure can be obtained. In this paper, rod-shaped Co-MOF-74 was grown on Ni Foam (NF) by hydrothermal method, and then Co-MOF-74/NF precursor was heat-treated to obtain rodshaped Co₃O₄/NF. Ni Foam was skeleton structured, which effectively relieved. The change of internal stress changes and destroys the structural volume of the electrode material and reduces the capacity attenuation. Co₃O₄/NF composite material has a specific discharge capacity of up to 1858 mA h/g for the first time, and a reversible capacity of up to 902.4 mA h/g at a current density of 200 mA/g, and has excellent rate and impedance performance. The synthesis strategy reported in this article opens the way to design high-performance electrodes for energy storage and electrochemical catalysis.

• 한국전자파학회논문지
• /
• 제17권12호
• /
• pp.1150-1155
• /
• 2006

본 논문에서는 대역 통과 필터의 입력부에 응용되는 탭 선로의 등가 회로를 제시하였고, 그 변수 값을 수식적으로 제시한다. 탭 선로의 등가 회로는 개방형 스터브와 음의 전기적 길이를 갖는 전송 선로로 구현하며, 탭 선로의 위치와 공진기 길이는 공진기의 임피던스와 인버터 값으로 구할 수 있다. 이러한 새로운 등가 회로에 의한 설계는 기존의 방법에 비해 이론적으로 근접한 결과를 얻을 수 있게 한다. 새로운 탭 선로의 등가 회로를 이용한 헤어핀 대역 통과 필터는 중심 주파수 2 GHz에서 1.1 dB의 삽입 손실과 20 dB의 반사 손실 특성을 나타낸다.

• 한국학교보건학회지
• /
• 제19권1호
• /
• pp.67-78
• /
• 2006

Purporse : The purpose of this study was to examine the relationship between a health promoting lifestyle and body composition in university students. The study subjects were 194 university students who attended K-university located in Chungnam. Methods : The data was collected between March 2 and May 31, 2004. The instrument used for this study was the modified Health Promoting Lifestyle Profile(HPLP) developed by Walker, Sechrist, & Pender(1987). The body composition was measured by In Body 3.0, a Bioelectrical Impedance Analyzer. The data was analyzed using the SPSS/WIN 10.0 program by t-test, ANOVA and pearson correlation coefficients. Results : The results of this study are as follows: 1) The scores of the Health Promoting Lifestyle(HPL) ranged from 79 to 170, with a mean score of 110(±15.8). The mean scores of sub-categorical HPL were self-actualization 31.8(±4.9), health responsibility 17.0(±4.0), exercise 8.3(±3.2), nutrition 15.4(±3.7), interpersonal relationships 20.3(±3.5) and stress management 17.2(±3.4). 2) The HPL according to the subjects' general characteristics had significant correlation to exercise amount(F=8.09, p＜.01), drinking amount(F=6.56, p＜.01), perceived health status(F=19.2, p＜.01) and perceived health knowledge (F=15.9, p＜.01). 3) The total HPL did not significantly correlate with any categories in body composition. The exercise area of sub-categorical HPL had significant positive correlation to height (r=.199, p＜.01), weight(r=.181, p＜.05) and soft lean mass(r=.257, p＜.01), and negative correlation to percent body fat(r=-.255, p＜.01) in body composition. Conclusion : The results suggest that the exercise area of sub-categorical HPL was an important variable for an exercise program's development such as nursing intervention for the health promotion of university students.

• 센서학회지
• /
• 제7권2호
• /
• pp.83-89
• /
• 1998

$TiO_{2-x}$ 박막 습도센서를 스퍼터링법에 의해 제조하고, 스퍼터링 조건과 열처리조건에 따른 습도 감지특성 및 동작온도에 따른 특성 등을 조사하였으며, Auger 전자 분광기와 전자현미경으로 그 원인을 분석하였다. $TiO_{2-x}$ 박막 습도센서는 부임피던스 습도특성을 보였으며, rf power가 200 W, 압력은 50 mTorr 및 기판 온도는 $200^{\circ}C$ 에서 증착하고, $600^{\circ}C$에서 1시간 동안 열처리한 소자의 상대습도 변화에 따른 임피던스 변화는 $0.794\;K{\Omega}/%RH$로 가장 컸으며, 응답 시간은 흡착시 약 2분, 탈착시 약 3분이었다.

• Korean Chemical Engineering Research
• /
• 제52권1호
• /
• pp.52-57
• /
• 2014

본 연구에서는 낮은 사이클 안정성을 갖는 MCMB의 단점을 향상시키기 위하여 높은 사이클 안정성과 부피팽창이 없는 장점을 갖는 물질인 $Li_4Ti_5O_{12}$를 코팅하여 core-shell 구조의 $MCMB/Li_4Ti_5O_{12}$를 합성하고 $MCMB/Li_4Ti_5O_{12}$를 음극으로, $LiMn_2O_4$, Active carbon fiber를 양극으로 사용하여 단위 셀을 제조하였다. $LiPF_6$ 염과 EC/DMC/EMC 용매를 전해질로 사용하여 제조한 하이브리드 커패시터 단위 셀로 충방전, 사이클, 순환전압전류, 임피던스 테스트를 진행하여 전기화학적 특성을 평가한 결과, MCMB-$Li_4Ti_5O_{12}/LiMn_2O_4$ 전극을 사용한 하이브리드 커패시터가 MCMB 전극의 하이브리드 커패시터 보다 좋은 충/방전 성능을 보였고, 67 Wh/kg, 781 W/kg의 에너지밀도와 출력밀도를 나타내었다.

• 대한지역사회영양학회지
• /
• 제8권6호
• /
• pp.977-985
• /
• 2003

This study was done to evaluate the health and nutritional status of female college students in Seoul. The subjects were 63 healthy college students aged 20 to 29 years. Their body composition, dietary intakes, clinical blood indices were investigated. Their body composition was determined by means of a multifreqency bioelectrical impedance analysis. Their dietary intake was determined using 3-day record method and their nutrient intake was analyzed by Computer Aided Nutritional analysis program for professional (CAN-pro). Their hemoglobin, hematocrit, red blood cell (RBC), white blood cell (WBC) and mean corpuscular volume (MCV) were determined by semi-automated microcell counter (F-520). Their plasma total cholesterol, TG, and HDL-cholesterol levels were measured using test kits. All data were statistically analyzed by SAS PC package program. Their average consumption of calcium, iron vitamin A, vitamin B2 and niacin were 63.3%, 65.0%, 85.2%, 89.2% and 95.2% of RDA, respectively. The overall mean values of the hematological indices in the female college students were within the normal range. However anemic subjects with hemoglobin (< 12 g/dl) and hematocrit (<36%) accounted for about 20% of the subjects. The mean levels of total cholesterol, HDL-cholesterol and TG were 188.4mg/dl, 69.9mg/dl and 67.4mg/dl, respectively. The percentages of the subjects with plasma total cholesterol level (> 200mg/dl) and LDL-cholesterol (＞130mg/dl) were about 41% and 30.4%, respectively. The data showed a significantly positive correlation between either body fat (%) or BMI and TG. However. there was a significantly negative correlation between either body fat (%) or BMI and HDL-cholesterol. These overall results suggest that it is necessary for college women to be educated regarding consuming more iron and vitamin C and less fat, in order to prevent iron deficiency anemia and/or cardiovascular diseases in later life.

• 전기화학회지
• /
• 제18권3호
• /
• pp.130-135
• /
• 2015

흑연 분말을 프탈로시아닌 또는 구리 프탈로시아닌과 함께 비활성 분위기에서 각각 열처리하여 표면처리를 진행하였고, 이의 속도특성과 저온 작동특성을 조사하였다. 표면처리 후 흑연 분말의 표면에 비정질 탄소와 구리의 코팅 층이 균일하게 형성되었다. 표면처리를 통하여 흑연 전극의 속도특성이 개선되는 것을 확인하였는데, 특히 구리 프탈로시아닌으로 처리한 경우 속도특성의 향상이 두드러졌다. 흑연 전극의 저항을 교류 임피던스와 펄스 저항측정법을 활용하여 조사하였는데, 구리 프탈로시아닌으로 처리된 흑연 전극의 경우가 저항이 가장 작았다. 프탈로시아닌으로 부터 유도된 비정질 탄소 층이 리튬이온의 확산을 용이하게 하고, 구리 프탈로시아닌으로부터 유도된 금속상태의 구리는 전자 전도도를 증가시키기 때문에 저항을 감소시키는 것으로 판단된다.

• 한국조명전기설비학회지:조명전기설비
• /
• 제11권2호
• /
• pp.51-55
• /
• 1997

고주파용 형광램프 시스템은 높은 발광효율 때문에 일반적으로 많이 사용되고 있다. 그러나, 이 고주파용 형광램프의 동작 특성은 동작주파수, 램프형상, 램프전압 및 전류값과 전자식안정기와 코아식안정기의 사용에 따라서 차이가 많이 난다. 그렇기 때문에 형광램프의 특성은 안정기의 특성을 고려한 형광램프 시스템의 동작특성 정합성에 매우 중요하다. 본 논문에서는 FHF32W(T8)형광램프의 고주파 특성을 가장 많이 사용되는 주파수 영역(12[kHz]∼50[kHz]에서 측정, 분석하였다. 특히 램프전류의 변화에 따른 형광램프의 비선형 임피던스를 모델링해서, 램프전류 변화에 의한 형광램프의 부임피던스 동작특성을 파악하여 고주파 형광램프의 최적 특성치를 선택할 수 있는 방법을 제시하였다.