• 제목/요약/키워드: density analysis

검색결과 8,990건 처리시간 0.032초

이중에너지 방사선 흡수계측법(DEXA)을 이용한 성인들의 체구성과 골밀도 분석 (The analysis of body composition and bone mineral density in adult by using dual energy X-ray absorptiometry)

  • 이중철;한상완
    • The Journal of Korean Physical Therapy
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    • 제15권4호
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    • pp.466-478
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    • 2003
  • This study was to evaluate the body composition and bone mineral density according to aging in adult and investigated the relationship between various parameters such as body mass index(BMI), bone mineral density(BMD), bone mineral content(BMC), lean body mass(LBM), fat mass(FM) and the value obtained from dual energy X-ray absorptiometry(DEXA). The subjects were composed of healthy adult male and female who were $20^{\sim}73$ years old and they were divided three group according to age (A group : 20-39 yrs., B group : 40-59 yrs., C group : more than 60 yrs.). The conclusion derived from statistical analysis was as follows : 1. Bone mineral content and density were significantly affected by lean body mass(relatively, R=0.85 - 0.63). 2. There was significant difference among age groups in total bone mineral density. 3. There was significant difference among age groups in bone mineral content of male and female. 4. Lean body mass is diminished according to age, but there was not significant difference among age groups. 5. Fat mass of A group in male had the highest mass and followed by C group and B group. In female groups, fat mass of A group had the highest mass and followed by B group and C group. Abdominal fat mass is increased according to age. This result suggest that aging was closely relation with loss of muscle mass, bone mineral density and bone mineral content.

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Analysis of the oxidized low density lipoprotein receptor 1 gene as a potential marker for carcass quality traits in Qinchuan cattle

  • Gui, Lin-sheng;Raza, Sayed Haidar Abbas;Jia, Jianlei
    • Asian-Australasian Journal of Animal Sciences
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    • 제32권1호
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    • pp.58-62
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    • 2019
  • Objective: The oxidized low density lipoprotein receptor 1 (OLR1) gene plays an important role in the degradation of oxidized low-density lipoprotein and adipocyte proliferation in mammals. For this reason, we aimed at investigating the association of OLR1 gene polymorphisms with carcass quality traits in Chinese Qinchuan cattle. Methods: The single nucleotide polymorphism (SNP) was identified in the 3' untranslated region of bovine OLR1 gene by DNA sequencing. In addition, the haplotype frequency and linkage disequilibrium estimates of three SNPs were evaluated in 520 individuals. Results: Results indicated that the studied three SNPs were within the range of moderate genetic diversity (0.25< polymorphism information content<0.5). Haplotype analysis of three SNPs showed that ten different haplotypes were identified, but only five haplotypes were listed as those with a frequency of <0.05 were excluded. The Hap3 ($-G_1T_2C_3-$) had the highest haplotype frequency (42.10%). Linkage disequilibrium analysis showed that the three SNPs had a low linkage ($r^2<0.001$). The T10588C and C10647T were significantly associated with backfat thickness and intramuscular fat content in Qinchuan cattle. Conclusion: Based on our results, we believe that the OLR1 gene could be a strong candidate gene for influencing carcass quality traits in Qinchuan cattle.

비선형 부식분포를 고려한 철근덮개 파괴해석 (Fracture Analysis Considering the Non-uniform Corrosion Distribution)

  • 오병환;장봉석
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.1041-1044
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    • 2001
  • This study was performed to evaluate the effect of non-uniform corrosion distribution on the analysis of concrete cover failure. A series of experiments have been undertaken to measure the corrosion rate of reinforcement according to the concentration of chloride ion so as to suggest a relationship between the reinforcement corrosion rate and chloride ion density. The corrosion induced pressure depending on the density of chloride ion has been derived. And nonlinear analysis assuming nonlinear corrosion distribution for cover cracking was achieved and compared with other experimental results to verify the accuracy of the model. Analysis was also performed for various parameters to compare their effects.

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컨볼루션 기법을 이용한 영역이 제한된 비정규 확률문제의 신뢰성 해석 (Reliability Analysis of the Non-normal Probability Problem for Limited Area using Convolution Technique)

  • 이현만;김태곤;최원;서교;이정재
    • 한국농공학회논문집
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    • 제55권5호
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    • pp.49-58
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    • 2013
  • Appropriate random variables and probability density functions based on statistical analysis should be defined to execute reliability analysis. Most studies have focused on only normal distributions or assumed that the variables showing non-normal characteristics follow the normal distributions. In this study, the reliability problem with non-normal probability distribution was dealt with using the convolution method in the case that the integration domains of variables are limited to a finite range. The results were compared with the traditional method (linear transformation of normal distribution) and Monte Carlo simulation method to verify that the application was in good agreement with the characteristics of probability density functions with peak shapes. However it was observed that the reproducibility was slightly reduced down in the tail parts of density function.

분말단조 공정의 3차원 유한요소해석 (Three Dimensional Finite Element Analysis for Powder Forging Process)

  • 김형섭
    • 한국분말재료학회지
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    • 제3권2호
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    • pp.104-111
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    • 1996
  • In order to obtain homogeneous and high quality products in powder compaction forging process, it is very important to control stress, strain, density and density distributions. Therefore, it is necessary to understand quantitatively the elasto-plastic deformation and densification behaviors of porous metals and metal powders. In this study, elasto-plastic finite element method using Lee-Kim's pressure dependent porous material yield function has been used for the analysis of three dimensional indenting process. The analysis predicts deformed geometry, stress, strain and density distribution and load. The calculated load is in good agreement with experimental one. The calculated results do not show axisymmetric distributions because of the edge effect. The core part which is in contact with the indentor and the outer diagonal edge part are in compressive stress states and the middle part is in tensile stress state. As a results, it can be concluded that three dimensional analysis is more realistic than axisymmetric assumption approach.

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지하철 터널 균열밀도 분석을 통한 합리적인 보수보강 방안 연구 (Study on a rational repair and reinforcement by analysis of crack density in OO subway)

  • 윤태국;신용석;안상로;이송
    • 한국터널공학회:학술대회논문집
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    • 한국터널공학회 2005년도 학술발표회 논문집
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    • pp.262-269
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    • 2005
  • The priority order about a rational repair and reinforcement is generally decided by subjective decision of engineer. An appearance investigation by tunnel scanner that is widely used in foreign nation was carried out to decide about a rational repair and reinforcement through systematic and objective analysis in box and NATM tunnel. We have decided on the order of priority of an rational repair and reinforcement through the crack density analysis by span, distance and location with the result of tunnel scanner.

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분말컨넥팅로드 단조의 유한 요소 해석 (Finite Element Analysis of P/M Connecting Rod Forging)

  • 박종진
    • 소성∙가공
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    • 제1권1호
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    • pp.33-41
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    • 1992
  • Sintered P/M connecting rod is forged to increase density and to satisfy dimensional specifications. Flow of the materials is different form that of wrought materials due to pores in the preform. The Mises yield function was modified to. include the first invariant of stress tensor, and the associated flow rule was derived by applying the normality rule to the yield function. Axisymmetric and plane-strain finite element analyes were carried out for the ring and beam portions of the connecting rod, respectively. The flow of the preform and density change of the analysis are presented in this paper. A load-stroke curve was also presented by superimposing analysis results for the ring and beam portions.

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액체로켓엔진의 성능 민감도 분석 (Performance Sensitivity Analysis of Liquid Rocket Engine)

  • 조원국;박순영
    • 항공우주기술
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    • 제12권1호
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    • pp.200-206
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    • 2013
  • 액체로켓엔진에서 추진제 밀도와 공급 압력 변화에 대한 성능 민감도를 분석하였다. 해석 프로그램은 터보펌프-가스발생기 연계시험 결과와 비교하여 1% 오차를 가지는 것으로 확인되었다. 연료 공급압력이 증가하면 혼합비 감소로 인해 엔진 연소압이 감소하였고 연료의 밀도가 증가하면 혼합비 감소에도 불구하고 추진제 유량이 증가하므로 엔진 연소압이 증가하는 것으로 예측되었다. 또한 산화제의 밀도가 증가되거나 공급압력이 증가하면 엔진의 연소압이 증가할 것으로 분석되었다.

PHASE ANALYSIS FOR THE PREDATOR-PREY SYSTEMS WITH PREY DENSITY DEPENDENT RESPONSE

  • Chang, Jeongwook;Shim, Seong-A
    • 한국수학교육학회지시리즈B:순수및응용수학
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    • 제25권4호
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    • pp.345-355
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    • 2018
  • This paper looks into phase plane behavior of the solution near the positive steady-state for the system with prey density dependent response functions. The positive invariance and boundedness property of the solution to the objective model are proved. The existence result of a positive steady-state and asymptotic analysis near the positive constant equilibrium for the objective system are of interest. The results of phase plane analysis for the system are proved by observing the asymptotic properties of the solutions. Also some numerical analysis results for the behaviors of the solutions in time are provided.

공진주파수에 의한 목재의 동적탄성계수 추정 (Estimation of the Dynamic MOE in Woods with Resonance Frequency)

  • 이원희;황권환
    • Journal of the Korean Wood Science and Technology
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    • 제25권1호
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    • pp.42-49
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    • 1997
  • The purpose of this study was to investigate the relationships among density, moisture content, and modulus of elasticity in which are important characteristics in physical and mechanical properties of woods. In this study, the dynamic MOE was calculated through the combination with resonance frequency of transverse vibration method and density, and the estimated moisture contents were calculated with two different equations (1, 2) in order to compare with experimental moisture contents. The following results from this study were obtained: 1. According to the regression analysis with two different parameters (E and density), the two regression lines appeared to be straight intersecting at 0.6 density. As another factor, moisture contents in wood also influenced on the analysing regression at the below F.S.P. 2. When considering the relationship between moisture contents and E, the tendency of each moisture content and E showed very similar pattern suggesting that moisture contents in addition to density are very important parameter. 3. When together with moisture contents and density as parameters for multiple regression analysis, coefficiences of determinations are dramatically improved. Interestingly, the coefficiences of determinations are further increased when analysing at the below point of F.S.P. and when analysing higher and lower density separately. In summary, more correct estimation of the dynamic MOE of woods can be possible with only transverse vibration and density in wood. Therefore, with this indirect method, the calculation of MOE in all kinds of woods including timber, live tree and wood products can be feasible resulting in accelerating the efficiency of time and labor.

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