• 제목/요약/키워드: impedence

검색결과 106건 처리시간 0.018초

La 첨가량에 따른 Bi$_{4-x}La_x$Ti$_3O_12$ 강유전체의 주파수특성 (The Ferroelectric Frequency characteristics of Bi$_{4-x}La_x$Ti$_3O_12$ ceramics with the variation of Lanthanum additives)

  • 김응권;박복기;박기엽;박춘배
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.463-466
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    • 2001
  • In recent year, Ferroelectric BLT($Bi_{4-x}$La$_{x}$Ti$_3$O$_{12}$) is a promising candidate materials. This study was Practiced to make good conditions of BLT targets. In this study, calcination and sintering temperature were kept at 75$0^{\circ}C$, 110$0^{\circ}C$ for 2 hour respectively. the density obtained 7.612, 7.98, 7.877 g/㎤ as La$_2$O$_3$ contents were 0.0mol%, 0.25mo1%, 0.5mol%. Especially, the lanthanum content of 0.5 mol% measured C-axis (117) preferred orientation more than the others targets in the XRD. In $\varepsilon$$_{r}$-f relationship using by HP 4194 A impedance analyzer, the 0.5 mol% observed above 200 relative dielectric constant. but the dissipation factor was higher than others targets at 100Hz~13MHz range. SEM photograph with the content of La$_2$O$_3$ was observed like rod and plate types.types.s.

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비만치료에 유용한 단순비만지표의 선별 (Assessment of Anthropometric Obesity Indexes by Correlation with Body Composition)

  • 류수민;신승우;김길수;심우진
    • 한방비만학회지
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    • 제6권1호
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    • pp.69-80
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    • 2006
  • Object : Waist circumference(WC), waist-hip ratio(WHR), waist-stature ratio(WSR), and body mass index(BMI) are commonly used for evaluating obesity. This Research were done to determine what is more sensitive obesity indexes(WC, WHR, WSR, BMI) Correlated with body composition such as body fat mass, body fat(%), visceral fat area, and fat free mass. And what is more sensitively correlated obesity indexes with % changes of body composition during weight reduction treatment. Methods : This clinical retrospective research were carried out 127 cases of female obese outpatients with weight reduction treatment during 1 month. Bioelectrical impedence analysis(for body composition) and body size(for anthropometric obesity indexes) were estimated in pre-treatment and post-treatment to evaluate the obesity indexes. Pearson correlation coefficients were used to select useful obesity index. Result & Conclusion : BMI is useful index for diagnosis and evaluation of obesity. WSR is sensitively correlated with visceral fat area and body fat(%). So, WSR is useful index for evaluating abdominal obesity and risk factors of metabolic syndrome. WC is correlated with both body fat mass and fat free mass. WHR is not optimal for diagnosis and evaluation of obesity.

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Circuit training과 마황(麻黃) 복용이 태음인 여성의 심폐기능향상과 체지방감소에 미치는 상관성 연구 (Correlation between Cardiopulmonary System Function and Body Fat by Circuit Training and Ephedra Herba in Taeumin Women)

  • 박상호;조현철;최승범;송윤경;임형호
    • 한방재활의학과학회지
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    • 제15권1호
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    • pp.39-65
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    • 2005
  • Objectives : This study was aimed to find out correlation of relation between cardiopulmonary function and body fat. Methods : We studied tendency of change of cardiopulmonary function and body fat for medication of Ephedrae Herba capsule by ergogenic aids with circuit training. We got the results for Exercise stress test and Segmental Bioelectrical Impedence Analysis. Results : 1. Sample Group of Ephedrae Herba medication and Circuit training generally showed the insignificant improvement of Body composition, but Control Group of Placebo and Circuit training significantly(p<.05) showed significant improvement of Body composition. 2. Sample Group of Ephedrae Herba medication and Circuit training generally showed the significant improvement of cardio-pulmonary function. Control Group of Placebo and Circuit training showed insignificant elevation of Cardiopulmonary function. 3. In the case of Sample Group, there wasn't closely correlation relationship of improvement of cardiopulmonary function and body composition, but in the case of Control Group, there was closely correlation relationship of improvement of cardiopulmonary function and body composition. Conclusions : It might be recognized that cardiopulmonary function has the correlation of body composition, and Ephedrae Herba might help the reduction of Body Fat by elevation of Cardiopulmonary function for ergogenic aids and it might be needed further study In various viewpoints.

공심 평면인덕터의 임피던스 해석 (Impedence Analysis of Planar Air Core Inductor)

  • 김영학;송재성
    • 한국자기학회지
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    • 제6권3호
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    • pp.179-188
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    • 1996
  • spiral 패턴과 meander 패턴의 공심 평면 인덕터에 대해 주파수, 도체간격, 도체폭, 턴수등을 변화시켜 저항, 인덕턴스와 같은 전기적인 특성치의 이론적인 예측에 대해 검토하였다. 도체폭이 커짐에 따라 저항과 인덕턴스는 감소한다. 이때 Q는 spiral pattern에서는 최대치를 가지는 도체폭이 존재하는 반면 meander pattern에서는 저항의 감소가 인덕턴스의 감소보다 작아지므로 도체폭이 증가하면 Q가 증가하였다. spiral pattern에서는 도체간격을 작게할 때 저항, 인덕턴스, Q는 더 이상 증가하지 않는 도체간격이 존재하지만 meander pattern에서는 인접 도체 사이의 상호 인덕턴스의 부호가 (-)가 됨에 따라 도체 간격은 가능한 한 커야 한다. 턴수가 증가함에 따라 저항, 인덕턴스는 증가하며 spiral pattern에서는 최대의 Q를 가지는 턴수가 존재하지만 meander pattern에서는 인덕턴스의 증가보다 저항의 증가가 크기 때문에 턴수의 증가에 따라 Q는 감소하였다.

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여대생의 골밀도와 신체조성 및 생활습관과의 관계 연구 (The Relationship between Bone Mineral Density and Body Composition, Life Styles of Female College Students)

  • 이종현;이보경;김영순
    • 한국식품영양학회지
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    • 제24권4호
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    • pp.786-796
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    • 2011
  • The purpose of this study was to investigate the relationship between bone mineral density(BMD), body composition and life styles of female college students. The subjects were 334 students with a mean age of 21.0 years. BMDs of forearm and calcaneus were measured by dual energy X-ray absorptiometry, and body composition was measured by bioelectrical impedence analysis. The means for weight, height, and body mass index(BMI) of the subjects were 55.7 kg, 161.0 cm, 21.5 kg/$m^2$, respectively. Grouping by the BMI, 13.2% of the subjects were classified as overweight, and 11.1% of the subjects as obese group. BMD in the forearm and calcaneus were 0.390 g/$cm^2$, 0.514 g/$cm^2$. In the forearm, 58.1% and 9.6% of the subjects were classified as osteopenia and osteoporosis, respectively, and in the calcaneus, 12.0% and 0.3% of the subjects were classified as osteopenia and osteoporosis, respectively. Body weight, skeletal muscle mass, lean body mass, fat mass and BMI were positively correlated with BMDs in the forearm and calcaneus($r$=0.180~0.495, $p$ <0.01~0.001), and height, % body fat and waist-hip ratio(WHR) were positively correlated with BMDs in the calcaneus($r$=0.213~0.239, $p$ <0.001), but not in the forearm. The factors such as beginning age of cigarette smoking and alcohol drinking and exercise had significant influence on BMD($p$ <0.05; p<0.001), whereas sleeping hours, activity level, frequency of exercise, meal times, frequency of snack and fried food intake, breakfast skipping and amount of meal had not significant influence on BMD. Therefore, the acquisition of balanced body composition is necessary through the increase of fat free mass and muscle mass, not through the increase of fat mass among female college students.

전이암 환자의 예후 판단 인자로서 생체전기 임피던스 분석을 이용한 위상각의 역할 (Phase Angle Using Bioelectrical Impedance Analysis for Predicting Survival in Patients with Metastatic Cancer)

  • 윤성수;윤성우;류한성;김은혜;이지영
    • 대한한방내과학회지
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    • 제39권4호
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    • pp.463-470
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    • 2018
  • Objectives: The aim of this study was to identify the validity of phase angle as a prognostic factor for survival in patients with metastatic cancer. Methods: Data of patients with metastatic cancer who visited the Korean medicine cancer center at Kyung Hee University Hospital in Gangdong from April 2016 to February 2018 were collected for this study. The values of phase angle (PhA) and blood hemoglobin (Hb), C-reactive protein (CRP), and serum albumin levels were also investigated by bioelectrical impedance analysis (BIA). Results: In total, 86 patients were analyzed. The cut-off value of the phase angle was determined as 5.0. Univariate and multivariate analysis revealed that phase angle (HR 3.15, 95% CI 1.79-5.54) and CRP (HR 2.15, 95% CI 1.24-3.73) predicted survival with statistical significance. The median overall survival of the low PhA group ($PhA{\leq}5.0$) was 1.8 months (95% CI 0.6-2.9 months) and 7.2 months (95% CI 5.2-9.2 months) in the high PhA group (PhA>5.0)(p<0.001). Conclusions: The phase angle could be an independent prognostic factor for patients with metastatic cancer. Further research is required to confirm these findings and their correlation with other indexes.

개에서 고막과 고실의 초음파학적 평가 (Ultrasonographic Assessment of the Tympanic Membrane and Tympanic Bulla in Normal Dogs: A Preliminary Study)

  • 이해운;엄기동;성윤상;이종원;김정은;오태호;정규식;장광호;장동우
    • 한국임상수의학회지
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    • 제21권2호
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    • pp.97-101
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    • 2004
  • This study was aimed for ultrasonographic assessment of the tympanic membrane and the tympanic bulla in five healthy Beagle dogs. To improve an ultrasonographic image, the ear canal was filled with warm saline, and an 11 MHz linear probe and a 6.5 MHz convex probe were used. The structures of ear component such as ear canal, ear cartilage and tympanic membrane were easily identified. Especially, tympanic membrane was presented as a reflaction surface which was resulted from the different acoustic impedence between the fluid-filled anechoic ear canal and the gas-filled hyperechoic tympanic cavity in normal dogs. In five left-side ears, the saline was infused into the external ear canal after the tympanic membrane had been ruptured experimentally. Both anechoic fluid-filled ear canal and tympanic cavity were clearly identified. In five right-side ears, the surgically fluid-filled tympanic cavity was imaged as a hypoechoic oval shaped structure. When tympanic cavity and ear canal have been contained with fluid, it was difficult to identify whether the tympanic membrane was ruptured or not. For assessment of the ear structure with ultrasonography, the 11 MHz linear probe was considered as an optimal equipment for a serial assessment of ear canal, tympanic membrane and tympanic bulla whereas the 6.5 MHz convex probe was suitable to assess the tympanic cavity. The results suggest that ultrasonography with saline infusion into the ear canal can be used to find the intactness of the tympanic membrane and to assess the fluid- filld tympanic bulla.

전자근관장 측정기의 정확도에 관한 연구 (IN VIVO EVALUATION OF ACCURACY OF TWO ELECTRONIC APEX LOCATORS)

  • 김회정;홍찬의
    • Restorative Dentistry and Endodontics
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    • 제21권1호
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    • pp.289-299
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    • 1996
  • It is necessary to measure the length of a root canal in order to attain a satisfactory prognosis after root canal therapy. There are several methods for determining root canal length, such as tactile sensation by the dental practitioner, the utilization of x-ray film, and electronic root canal measurement. Among these, the electrical measurement methods, in which the impedence between the oral mucous membrane and periodontal membrane is determined, have advantages of simplicity and accuracy. During root canal treatment, the root canal contains a solution of high electrical conductivity such as pus, blood, sodium hypochlorite and so on. Recently a new electronic root canal measurement device of frequency-dependent type has been developed, which is capable of measuring the length of root canal under moist conditions. Endex and Root ZX, which are frequency-dependent type, were evaluated for accuracy of measuring root canal length in vivo by stereomicroscope. The result were as follows ; 1. 82.5% of Endex and 87.5% of Root ZX measured in the range of ${\pm}0.5$ mm from the apical foramen and both showed 57.5 % in the range of 0.1 mm to 0.5 mm. 2. Endex showed significantly higher accuracy in vital teeth than nonvital teeth(p<0.05). But in case of Root ZX, there was no significant difference between vital and nonvital teeth. 3. As a result of this study, there was no significant difference in accuracy between Endex and Root ZX, and both devices showed file passes the apical foramen in more than half of the cases, and it is thought that this must be considered clinically.

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소아 체지방 평가를 위한 생체 저항분석법의 타당성 연구 : 이중 에너지 방사선 흡수법과의 비교 (Validity of Bioelectrical Impedance Analysis(BIA) in Measurement of Human Body Composition)

  • 김형석;김수영
    • Clinical and Experimental Pediatrics
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    • 제48권7호
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    • pp.696-700
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    • 2005
  • 목 적 : 소아 체지방 평가에 있어 여러 가지 방법 중 BIA를 이용한 체성분 분석은 비침습적이고, 경제적이며, 방사선 노출의 위험이 없이 검사가 용이해 반복 시행할 수 있다는 장점이 있는 반면 검사 결과의 정확성에 대해 확인해 볼 필요가 있다. 이에 BIA 및 이중 DEXA에 의한 측정치들을 비교하여 BIA의 타당성을 알아보고자 하였다. 방 법 : 2003년 7월에서 10월까지 4개월 동안 부산대학교병원 소아과 방문하였던 소아 100명(남아 58명, 여아 42명)을 연구대상으로 하여 연구 대상자들에 대하여 각각 신장, 체중, 피부두께를 측정하였으며, BIA 및 DEXA법을 이용하여 체성분(체지방량, 제지방량, 제지방률, 체수분량)을 분석하였다. 결 과 : BIA와 DEXA법을 통한 검사상 FBM, LBM, %BF의 상관관계는 남녀 모두에서 통계학적으로 의미있는 양의 상관관계를 보였으며, 통계학적으로 의미가 있었다(P<0.001). 특히 FBM에서 남녀 모두 상관 계수가 높았다. 결 론 : 소아 비만의 평가에 있어 BIA를 통한 체성분 분석은 장치가 간단하고 특별한 기술을 필요로 하지 않으며, 비침습적이면서 경제적일 뿐 아니라 측정치가 객관적이고 정확한 것으로 분석되었다.

성 성숙 속도가 다른 사춘기 초기 여자 어린이의 체구성 및 식생활 비교 (Comparisons of Dietary Intakes and Body Composition with Different Sexual Maturation Velocities in Korean Girls of Early Pubertal Age)

  • 장훈;박민경;백희영;정효지
    • Journal of Nutrition and Health
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    • 제40권1호
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    • pp.58-68
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    • 2007
  • The associations between dietary, body composition and sexual maturation were investigated among Korean girls of pubertal age in this study. Dietary intakes were collected by 3 day food records, body compositions were measured by bio-impedence analyzer and sexual maturation stages were determined with a self-administrated questionnaire using Tanner stages in 1,114 girls 9-13 years of age. Girls were divided into early maturation (EM) and late maturation (LM), based on the comparative maturation stages of breast and pubic hair among the same age groups by months. Subjects were excluded if their stage of maturation could not be divided into early and late groups. EM and LM groups consisted of 42.8% and 38.9% of subjects by breast stage and 67.4% and 22.8% by pubic hair stage. Girls in LM group had significantly lower in height, weight and bone mineral contents (p < 0.05). When nutrient densities of average daily intake of the two groups were compared, folate density was significantly higher among the LM group of breast stages (p < 0.01), and Ca, P, K, Vit. $B_1$, Vit. $B_2$ and folate densities were significantly higher among the LM group of pubic hair stages (p < 0.05). These results show that intakes of some micronutrients differ between children with faster and slower sexual maturation velocities at early pubertal stages. More longitudinal studies are needed to confirm whether such differences are consistent throughout the pubertal period.