• 제목/요약/키워드: Effective mass

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개폐식 대공간 구조물의 지진 응답 제어 성능 향상을 위한 TMD의 최적 질량에 관한 연구 (A Study on Optimum Mass of TMD for Improving Seismic Response Control Performance of Retractable-Roof Spatial Structure)

  • 김동형;김현수;강주원
    • 한국공간구조학회논문집
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    • 제19권3호
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    • pp.93-100
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    • 2019
  • In this study, the retractable-roof spatial structure was chosen as the analytical model and a tuned mass damper (TMD) was installed in the analytical model in order to control the seismic response. The analysis model is mainly consisted of runway trusses (RT) and transverse trusses (TT), and the displacement response was analyzed by installing TMD on those trusses. The mass of the single TMD which is installed in the analytical model was set to 1% of the total structure mass and the total TMD mass ratio was set to be 8% or 6%. In addition, the mass of a single TMD was varied depending on the number of installations. As a result of analyzing the optimal number of installations of TMD, the displacement response was reduced in all cases compared to the case without TMD. Above all, the case with 8 TMDs was the most effective in reducing he displacement response. However, in this case, as the load on the upper structure of the retractable-roof spatial structure increases, the total mass ratio of TMD was maintained and the number of TMDs was increased to reduce the mass ratio of one TMD.

행동요법이 중ㆍ고도 비만아동의 비만도, 피부두께, 지방량, 혈중지질농도 및 렙틴농도에 미치는 효과 (Effects of Behavior Modification on Obesity Index, Skinfold Thickness, Body Fat9 Serum Lipids, Serum Leptin in Obese Elementary School Children)

  • 김효신
    • 대한간호학회지
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    • 제33권3호
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    • pp.405-413
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    • 2003
  • Purpose: This study was performed to investigate effects of behavior modification on obesity index, skinfold thickness, body fat, serum lipids, serum leptin in obese elementary school children. Method: Forty seven students were selected from two elementary schools. Twenty four children in one school were assigned to experimental group and twenty three children in another school were assigned to control group. Experimental group was received 60~70 minutes of behavior modification once a week for 8 weeks. Result: Obesity index of the experimental group was significantly decreased after behavior modification. But there was no significant difference between two groups. The increase of skin fold thickness was significantly low in the experimental group compared to the control group. Percentage of body fat and fat mass were significantly decreased in the experimental group. Fat free mass was significantly increased in the experimental group. HDL-C, triglyceride and serum leptin between the experimental group and control group showed no significant difference. Conclusion: These results indicate that behavior modification is effective in decreasing percentage of body fat and fat mass, in less increasing skinfold thickness and in increasing fat free mass. In conclusion, behavior modification can be used as effective strategy for managing obesity in elementary school children.

만성골반염(慢性骨盤炎) 환자에 대한 치험일례(治驗一例) (Clinical study on one case of a patient with chronic PID)

  • 서지영;김윤상;임은미
    • 대한한방부인과학회지
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    • 제15권4호
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    • pp.218-227
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    • 2002
  • Pelvic Inflammatory Disease(PID) is a spectrum of inflammatory disorders of the female genital tract involving at least the endrometrium and may include the fallopian tubes, ovaries, and pelvic cavity. Women with PID acutely experience pain and are at risk for sepsis; however, the long-term complications such as chronic pelvic pain, organic changes like chronic salpingitis, adhesions, etc., and the significant increases in ectopic pregnancy and infertility are more important and hard to control. This study is about one patient who has chronic PID with inflammatory pelvic mass. The patient was treated with retention enema therapy which use herbs effective for reducing inflammation, resolution abdominal mass, promoting blood circulation. Also, treated with herbal medication of Danchisoyosan(丹梔逍遙散) and Moxibution at Zhongwan(中脘), Guanyuan(關元). After total treatment for three months, the patient's symptoms are improved and the size of inflammatory pelvic mass is reduced. This results indicates that the combination treatment, especially the retention enema therapy is effective on reducing symptoms of PID and the size of secondary inflammatory organic changes.

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Determination of some useful radiation interaction parameters for waste foods

  • Akman, F.;Gecibesler, I.H.;Sayyed, M.I.;Tijani, S.A.;Tufekci, A.R.;Demirtas, I.
    • Nuclear Engineering and Technology
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    • 제50권6호
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    • pp.944-949
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    • 2018
  • The mass attenuation coefficients (${\mu}/{\rho}$) of food waste samples (pomegranate peel, acorn cap, lemon peel, mandarin peel, pumpkin peel, grape peel, orange peel, pineapple peel, acorn peel and grape stalk) have been measured employing a Si(Li) detector at 13.92, 17.75, 20.78, 26.34 and 59.54 keV. Also, the theoretical values of the mass attenuation coefficients have been evaluated utilizing mixture rule from WinXCOM program. The results showed that the lemon peel has the highest values of ${\mu}/{\rho}$ among the selected samples. From the obtained mass attenuation coefficients, we determined some absorption parameters such as effective atomic number ($Z_{eff}$), electron density ($N_E$) and molar extinction coefficient (${\varepsilon}$). It was found that the $Z_{eff}$ values of all food wastes lie within the range of 4.034-7.595, whereas the $N_E$ of the studied food wastes was found to be in the range of $0.301-1.720{\times}10^{25}$ (electrons/g) for present energy region.

동조질량감쇠기와 동조액체기둥감쇠기의 건물응답의 제어성능 비교연구 (Comparative Study of Tuned Mass Damper and Tuned Liquid Column Damper for Response Control of Building structures)

  • 김홍진;김형섭;민경원;오정근
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2003년도 추계 학술발표회논문집
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    • pp.427-434
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    • 2003
  • In this study, the control performances of Tuned Mass Damper (TMD) and Tuned Liquid Column Damper (TLCD) are evaluated and compared for seismically excited structures. Results show that TLCD is more effective than TMD for interstory drift control while TLCD is as effective as TMD for acceleration control. In special, it is shown that interstory drifts are maximally controlled in lower floors and accelerations are reduced most in upper floors. This indicates that TLCD is an effective controller for earthquake-induced structures in terms of structural safety as well as serviceability.

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수소저장용 금속수소화물$(Mm\;(La_{0.6-0.8})\;Ni_{4.0}Co_{0.6}Mn_{0.2}Al_{0.2})$의 전열촉진 (Heat transfer enhancement of metal hydride $(Mm\;(La_{0.6-0.8})\;Ni_{4.0}Co_{0.6}Mn_{0.2}Al_{0.2})$ for hydrogen storage)

  • 배상철
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.33-36
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    • 2006
  • The effective thermal conductivities of $Mm\;(La_{0.6-0.8})\;Ni_{4.0}Co_{0.6}Mn_{0.2}Al_{0.2}$ (TL-492) with hydrogen and helium have been examined. Experiment results show that pressure has great influence on effective thermal conductivity in Low pressure range (below 0.5 MPa). And that influence decreases rapidly with increase of gas pressure. The reason is at low pressure, the mean free path of gas becomes greater than effective thickness of gas film which is important to the heat transfer mechanism in this research. And, carbon fibers have been used to try to enhance the poor thermal conductivity of TL-492. Three types of carbon fibers and three mass fractions have been examined and compared. Naturally, the highest effective thermal conductivity has been reached with carbon fiber which has highest thermal conductivity, and highest mass fraction. This method has acquired 4.33 times higher thermal conductivity than pure metal hydrides with quite low quantity of additives, only 0.99wt% of carbon fiber. This is a good result comparing to other method which can reach higher effect ive thermal conductivity but needs much higher mass fraction of additives too.

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터널 굴착으로 인한 터널인접 절리암반 투수계수 감소를 고려한 터널 내 지하수 유입량 산정방법 (Groundwater inflow rate estimation considering excavation-induced permeability reduction in the vicinity of a tunnel)

  • 문준식
    • 한국터널지하공간학회 논문집
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    • 제15권3호
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    • pp.333-344
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    • 2013
  • 본 연구에서는 절리 암반 내 터널굴착 시 지하수 유출량 예측량이 실제 계측치와 큰 차이가 나는 이유 중 하나인 터널주변 절리암반의 투수계수의 감소 현상에 대해 논의하였다. 현재 터널 설계 시 일반적으로 사용되고 있는 지하수 유출량 산정식은 터널주변 암반이 등방, 균질하고 일정한 투수계수를 유지한다고 가정한다. 하지만, 실제로는 터널주변 절리암반의 투수계수는 터널주변 유효응력 상태에 따라 변화하며, 절리 내 지하수 흐름에 따라 다시 터널주변 유효응력 분포가 영향을 받는 수리-역학적 상호거동을 보인다. 터널굴착 직후 터널 접선방향 유효응력이 응력집중과 간극수압 감소로 인해 급증하고 그에 따라 절리의 닫힘현상이 발생하며, 결과적으로 터널인접 절리암반 링 구간에서 투수계수가 급격히 감소하게 된다. 이러한 터널인접 링 구간 내에서 상당히 큰 간극수압 감소가 발생하게 되어 터널주변 간극수압 분포는 등방 균질의 절리암반으로 가정한 산정식과 큰 차이를 보인다. 본 연구에서는 절리암반의 수리-역학적 상호거동의 개념을 도입하여 터널주변 간극수압 분포와 터널 내 지하수 유입량 산정방법을 제안하고 이를 수치해석을 통해 검증하였다.

계면경사가 있는 GaAs/(Al, Ga)As 초격자의 밴드구조 (The Band Structure of GaAs/(Al,Ga)As Superlattice with Interface Grading)

  • 김장래;김충원;한백형
    • 대한전자공학회논문지
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    • 제25권3호
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    • pp.287-293
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    • 1988
  • This paper calculates the band structure of the GaAs/(Al,Ga) As semiconductor superlttice with the interface3 grading, in consideration of different effective masses in each region. Including the effective masses, superlattice period, well and barrier widths, and the interface, the dispersion relation is derived, and the effects that the above parameters affect the subband (or miniband) structure of the superlattice and effective energy gap are investigated. It is particularly found that this case(ma<>mb<>mc) is significantly different from the same effective mass case(ma<>mb<>mc).

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스톤마사지 테라피가 복부비만의 감소에 미치는 영향 (The Effects of Stone Massage Therapy on Abdominal Obesity Reduction)

  • 반소정;김정숙;김지현
    • 한국의상디자인학회지
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    • 제15권4호
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    • pp.17-27
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    • 2013
  • This study has the purpose to examine the effects of stone massage therapy on abdominal obesity reduction. 10 sessions for 5 weeks two times a week of stone massage therapy were offered to 43 adult females who were 40s through 70s with 27% or more of body fat and the results were analyzed. The body composition like body fat mass, fat free mass, weight and skeletal muscular mass etc and the degrees of obesity like body fat ratio abdominal fat ratio were measured and analyzed before and after stone massage therapy. The results are as follows: First, the subjects were obese body type and stone massage therapy produced positive effects with body fat mass, fat free mass, weight and BMI value slightly less than before the therapy. Second, as the average values of body fat ratio and waist hip ratio of subject were significantly different statistically before and after the therapy, stone massage therapy was found to be effective in reducing abdominal obesity. Third, as for the change of waist hip ratio, the therapy was found to be effective in reducing waist hip ratio that 40s decreased insignificantly after the therapy, and 50s and 60s significantly at p<0.05 level respectively from 0.92 to 0.90 and from 0.93 to 0.92. In conclusion, the results of this study indicated that stone massage therapy has positive effects on abdominal obesity reduction, and can contribute to healthy life and well-being culture.

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지중 시공 벽체의 매립장 침출수 차단성 연구 (The Study on Cutting-off the Leachate Leakage or Infiltration from Waste Landfill by Wall Mass Constructed in Underground)

  • 고용일
    • 한국지반환경공학회 논문집
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    • 제19권10호
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    • pp.27-34
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    • 2018
  • 원호활동파괴가 발생한 해안 폐기물 매립장에서 기초지반 전단강도의 보완과 폐기물 침출수가 지하수나 인접지반으로 유동되는 것을 차단하는 최종 시설로서 시멘트계 지중벽체를 시공한 후, 침출수 차단효과를 확인하였다. (1) 육안 확인 및 (2) 압축강도 시험에 의하면 지중에 시공된 벽체의 품질이 상당히 양호하다는 사실을 확인할 수 있고 (3) 현장 투수시험과 (4) 성분 및 성분비 분석과 (5) 질량 분석기를 통해서 얻게 되는 크로마토그램의 분포패턴 판정 등 중복적인 실험 및 조사 분석에 의해서 벽체의 수밀성이나 침출수의 이동에 대한 차단성이 매우 크다는 것을 확인할 수 있었다. 따라서, 폐기물 매립장 내에서 발생하는 침출수와 같은 고농도 환경오염수가 매립장 밖으로 유출되거나 침투하는 것에 대한 신뢰적인 차단 여부는 이 5가지의 조사 및 시험을 실시하는 방안에 의하여 객관적으로 판단될 수 있다고 사료된다.