• Title/Summary/Keyword: impedence

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A Study on Dietary Intakes and Nutritional Status in College Women Smokers -I. Anthropometric Measurements and Nutrient Intakes - (흡연 여대생의 식이섭취실태 및 영양상태 평가에 관한 연구 -I. 신체계측 및 식이섭취실태 -)

  • 김정희;이화신;문정숙;김경원
    • Korean Journal of Community Nutrition
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    • v.2 no.1
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    • pp.33-43
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    • 1997
  • In order to investigate the dietary intakes and physical characteristics in college women smokers, interviews using questionnaires were done on 33 smokers and 42 nonsmokers residing in seoul area. General living habits, dietary habits, food consumption frequency and nutrient intake by quick estimation were investigated through direct interviews with subjects. Subjects height, weight and blood pressure were measured, and body fat percentage were statistically analyzed using Bio-electrical Impedence Fatness Analyzer(GIF-891). All data were statistically analyzed by SAS PC package program ; percentage or mean and standard error were examined for each item, and the significant difference was evaluated by chi-square test or Student's t-test at $\alpha$=0.05. In the analysis of taste and food preference, smokers consumed larger amount of alcohol and coffee than nonsmokers ; they also disliked sweet taste. The results of food consumption frequency data also showed that smokers consumed less fish, milk and fruits but consumed more instant foods than nonsmokers. As a result of anthropometric measurements, height, age, and 패요 fat percentage showed no difference, but there was a significant difference in weight, BMI, systolic blood pressure, and diastolic blood pressure. Energy intake in nonsmokers was 1640 ㎉/day(CHO : Pro : Fat=66.0 : 14.7 : 19.3), in smokers. Intakes of calcium, iron, vitamin C, vitamin A, vitamin B1, vitamin B2, and niacin in smokers were not significantly different from those of nonsmokers.

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An Optimal Design of the Front Wheel Drive Engine Mount System (전륜구동형 승용차의 엔진마운트 시스템 최적설계)

  • Kim, M.S.;Kim, H.S.;Choi, D.H.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.1 no.3
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    • pp.74-82
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    • 1993
  • Optimal designs of a 3-point and a 4-point engine mount system are presented for reducing the idle shake of a Front Wheel Drive(FWD) vehicle. Design variables used in this study are the locations, the angles and the stiffness of an engine mount system. The goal of the optimization is minimizing the transmitted force without violating the constraints such as static weight sag, resonant frequency and side limits of design variables. The Augmented Lagrange Multiplier(ALM) Method is used for solving the nonlinear constrained optimization. The generalized Jacobi and the impedence method are employed for a free vibration analysis and a forced response analysis. The trend of analysis results well meet that of the experimental results. The optimization results reveal that the 4-point system transmits less torque than the 3-point system. It is also found from the design sensitivity analysis that the vibration characteristics of the 4-point system is less sensitive than those of the 3-point system.

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Multi-hole RF CCP 방전에서 방전 주파수가 미치는 영향

  • Lee, Heon-Su;Lee, Yun-Seong;Seo, Sang-Hun;Jang, Hong-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.145-145
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    • 2011
  • Recently, multi-hole electrode RF capacitively coupled plasma discharge is being used in the deposition of microcrystalline silicon for thin film solar cell to increase the speed of deposition. To make efficient multi-hole electrode RF capacitively coupled plasma discharge, the hole diameter is to be designed concerning the plasma parameters. In past studies, the relationship between plasma parameters such as pressures and gas species, and hole diameter for efficient plasma density enhancement is experimentally shown. In the presentation, the relationship between plasma deriving frequency and hole diameter for efficient multi-hole electrode RF capacitively coupled plasma discharge is shown. In usual capacitively coupled plasma discharge, plasma parameter, such as plasma density, plasma impedence and plasma temperature, change as frequency increases. Because of the change, the optimum hole diameter of the multi-hole electrode RF capacitively coupled plasma for high density plasma is thought to be modified when the plasma deriving frequency changes. To see the frequency effect on the multi-hole RF capacitively coupled plasma is discharged and one of its electrode is changed from a plane electrode to a variety of multi-hole electrodes with different hole diameters. The discharge is derived by RF power source with various frequency and the plasma parameter is measured with RF compensated single Langmuir probe. The shrinkage of the hole diameter for efficient discharge is observed as the plasma deriving frequency increases.

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Fabrication and Characteristics of Surface-Acoustic-Wave Sensors for Detecting $NO_2$ GaS ($NO_2$ 가스 감지를 위한 표면탄성파 센서의 제작 및 특성)

  • Choi, D.H.
    • Journal of Sensor Science and Technology
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    • v.8 no.2
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    • pp.108-114
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    • 1999
  • Surface acoustic wave (SAW) device is very attractive for gas sensor applications because of their small size, low cost, high sensitivity, and good reliability. A dual delay line surface acoustic wave $NO_2$ gas sensors have been designed and fabricated on the $LiTaO_3$ piezoelectric single crystal substrate. The capacitance of the fabricated IDTs was 326.34pF at the frequency of 79.3MHz. The maximum reflection loss of the impedence-matched IDTs was -16.74dB at the frequency of 79.3MHz. The SAW oscillator was constructed and the stable oscillation was obtained by controlling the gain of rf amplifier properly. The oscillation frequency shift of the SAW oscillator to the $NO_2$ gas was 28Hz/ppm.

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Ion Conduction Properties of PVDF/PAN based Polymer Electrolyte for Lithium Polymer Battery (리튬 폴리머전지용 PVDF/PAN계 고분자 전해질의 이온 전도 특성)

  • 이재안;김종욱;구할본
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.306-311
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    • 2000
  • The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li polymer battery. The temperature dependence of conductivity impedance spectroscopy and electrochemical properties of PDF/PAN electrolytes as a function of a mixed ratio were reported for PVDF/PAN based polymer electrolyte films which were prepared by thermal gellification method of preweighed PVDF/PAN plasticizer and Li salt. The conductivity of PVDF/PAN electrolytes was 10$\^$-3/S/cm. 20PVDF5PEN LiCiO$\_$4//PC$\_$10//EC$\_$10/ electrolyte has the better conductivity compared to others. 20PVDF5PANLICIO$\_$4//PC$\_$10//EC$\_$10/ electroylte remains stable up to 5V vs. Li/Li$\^$+/. Steady state current method and ac impedance were used for the determination of transference numbers in PVDF/PAN electrolyte film. The transference number of 20PVDF5PANLiCO$\^$4//PC$\_$10//EC$\_$10/ electrolyte is 0.48.

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Gender Differences in Obesity Rates, Nutrient Intakes, and Dietary Behaviors among College Students (남녀 대학생의 비만도, 영양소 섭취, 식행동에 관한 비교)

  • Yu, Ju-Young;Ro, Hee-Kyung
    • Journal of the East Asian Society of Dietary Life
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    • v.19 no.6
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    • pp.846-855
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    • 2009
  • This study was performed to assess gender differences in rates of obesity, dietary behaviors, and nutrient intakes among college students living in Gwangju. Anthropometric measurements showed that the body mass indexes (BMIs) of the males and females were $22.1{\pm}2.6$ and $20.1{\pm}2.4$ respectively. All obesity indices including BMI, relative body weight (RBW), % body fat by bioelectrical impedence analysis (BIA), and waist-hip ratio (WHR) were significantly higher in the males than in the females. Abdominal fat was also found to be higher in the males whereas underweight was prominent in the female students. The dietary behaviors of the males as determined by dietary scores, were poorer than those of the females. Twenty-four hour dietary recalls revealed that most nutrient intakes were adequate, exceptions of vitamin C, Ca, and folate intakes in both sexes and Fe intake in the female students. Ca and folate intakes were below 75% of the KDRI for both genders. In addition, Unbalanced energy ratios of carbohydrate, protein, and fat were noted in both genders. Effective nutrition education programs targeting college students should be developed and implemented to increase Ca and folate consumption. It is suggested that gender-based nutrition education approaches be created due to poor dietary behavior in males and inadequate nutrient intakes in female college students.

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DEVELOPMENT OF NEW FREQUENCY-DEPENDENT TYPE APEX LOCTOR ; VOLTAGE DIFFERENCE COMPENSATING TYPE (주파수의존형 전자근관장측정기의 개발과 정확도에 관한 연구 ; 전압차 자동보정형)

  • Lee, Seung-Jong;Kim, Deok-Won;Nam, Ki-Chang
    • Restorative Dentistry and Endodontics
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    • v.22 no.2
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    • pp.809-819
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    • 1997
  • The purpose of this study was to develop an accurate frequency-dependent type apex locator. To compensate the impedence differences of different canal contents, voltage differences were pre-measured and stored for saline, HOsb1/$2O_2$ and NaOCl. The circuit was adjusted to recognize the different voltages of each solution, thereby the machine could automatically compensate the voltage differences. In the process of this study, the following informations were observed. 1. Most stable apical reading was obtained at 500Hz and 10kHz. 2. There were no differences in accuracy among three different frequency types, sign wave, triangular wave and rectangular wave(p>0.05). 3. Before the compensation of voltage differences, saline, H2O2 and NaOCl showed different readings at the apex even with the frequency-type (p<0.05). 4. After compensating the voltage difference, the accuracy was enhanced from + 0.42 to +0.32 in H2O2(p<0.05), from -0.34 to -0.12 in NaOCl(p<0.05).

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Propagation and Radiation Characteristics of Elliptical Corrugated Waveguide (타원형 커루게이트 도파관의 전파 및 복사 특성)

  • 고욱희;백경훈
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.9 no.5
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    • pp.614-620
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    • 1998
  • In this paper, we analyze theoritically the propagation and radiation characteristics for elliptical corrugated waveguides. The solutions of wave equations in an elliptic cylinder system are obtained in terms of Mathieu functions of 1st and 2nd kind. The electromagnetic fields in the elliptical corrugated waveguide can be represented by series and products of angular and radial Mathieu functions. By using impedence matching at the boundary between the inner region and the slot region, characteristic equations are derived. Then the characteristic equation is solved for $HE_{11}$ mode which is dominant mode in the elliptical corrugated waveguide and the fields in the aperture is calculated. And the propagation pattern for the elliptical corrugated waveguides is calculated through the field equivalence principle.

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The Association Between Visceral Fat Area and Obesity Index (전산화 단층촬영과 생체 전기저항 분석법으로 측정한 내장지방과 비만관련 지표의 연관성)

  • Lim, Je-Yeon;Song, Yun-Kyung;Lim, Hyung-Ho
    • Journal of Korean Medicine Rehabilitation
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    • v.21 no.4
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    • pp.167-179
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    • 2011
  • Objectives: In this study, we used with visceral fat area(VFA)/subcutaneous fat area(SFA) ratio(V/S ratio) and bioelectrical impedence analysis(BIA) for a comparative study between VFA measured from several abdominal computed tomography(CT) images and obesity indexes, such as body mass index(BM), waist circumference(WC), and waist-hip ratio(WHR). Methods: A group of 63 test subjects were gathered in the oriental medical hospital of Kyung-Won university. BIA for body composition and body size for obesity indexes were estimated to evaluate the obesity indexes. Pearson correlation coefficients and regression analysis were used to select useful obesity index. Results: The VFA-CT was significantly related to BMI, SFA, WC, hip circumference(HC), body fat mass(BFM), basal metabolic rate(BMR), and VFA-BIA. Especially, we found that the VFA-BIA and BMI were significantly correlated to VFA-CT. Conclusions: VFA-BIA index is an optimized index for diagnosis and evaluation of obesity. Finally, we found that the BMI is optimized to represent VFA.

The Effect of Very low calorie diet and Chegameuiintang on Body Composition in Obese Patients (초저열량 식이요법과 체감의이인탕의 병행치료가 비만 환자의 신체조성에 미치는 영향)

  • Kim, Gil-Su;Kim, Dong-Yeol
    • Journal of Korean Medicine for Obesity Research
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    • v.1 no.1
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    • pp.21-32
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    • 2001
  • Objectives: The aim of this study was to the effect of very low calorie diet with Chegameuiintang to treat obese patients . Methods: We have evaluated 54 obese patients during very low calorie diet with Chegameuiintang weight-reducing regime by determining the body composition before and 1 month, 2 months after treatment by Bioelectrical impedence analysis . Results: In the change of body composition by the treatment, mean weight reduction was 11.59kg(15.57% of initial weight), mean weight reduction after 1month was 7.68kg( 10.31% of initial weight), mean weight reduction after 2 months was 3.91 kg(5.86% of weight after 1 month). Mean reduction in total fat mass was 8.03kg(2914% of the initial fat mass) which constitutes 69.28%. Mean reduction in lean body mass was 3.56kg(7.59%) Conclusions: This study has demonstrated that the compound therapy of very low calorie diet and Chegameuiintang (Tiganyiyiren-tang) is the good way of weight reduction, which reduces total fat mass and preserves lean body mass.

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