• Title/Summary/Keyword: 질량중심

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Optimum Design of Dynamic Vibration Absorber for Reducing Bending Vibrations of Two-Piece Vehicle Drive Line (2축 분할식 차량 구동라인의 굽힘진동 저감을 위한 동흡진기 최적설계)

  • Lee, Sang-Beom;Yoo, Young-Sun
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.2
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    • pp.118-124
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    • 2010
  • In this paper, design parameters of dynamic vibration absorber, which is used to reduce bending vibrations of a vehicle drive line, is optimized. For obtaining the correct dynamic response characteristics, a flexible-body drive line is made by applying the flexibility data extracted from vibration analysis of propeller shafts to the drive line dynamic model. Inner tube mass, rubber stiffness and rubber damping coefficient of the dynamic vibration absorber are taken as design parameters for optimization. To minimize the vertical acceleration of the drive line, a second-order regression equation of the objective function is generated by performing the central composite experimental design with 3 factors, 2 levels and 15 test runs. And the design parameters of the dynamic vibration absorber are determined by using optimization program. The vehicle model with optimized dynamic vibration absorber reduces the vertical acceleration peak of the drive line by 17.1 % in compared with the initial model.

Comparing Directional Parameters of Very Fast Halo CMEs (코로나질량방출의 방향지시 매개인수 비교)

  • Rho, Su-Lyun;Chang, Heon-Young
    • Journal of Astronomy and Space Sciences
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    • v.25 no.4
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    • pp.383-394
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    • 2008
  • We examine geoeffective directional parameters of coronal mass ejections (CMEs). We select 30 front-side halo CMEs from SOHO LASCO CMEs whose speed is larger than 1000km/s and longitude is less than ${\pm}30^{\circ}$. These are thought to be the most plausible candidate of geoeffective CMEs. We examine the relation between CMEs directional parameters (Earthward direction, eccentricity, ${\Delta}$ distance and central angle parameter) and the minimum value of the Dst index. We have found that the Earthward direction parameter has a good correlation with the Dst index, the eccentricity parameter has a much better correlation with the Dst index. The bo distance and central angle parameter has a poor correlation with the Dst index. It's, however, well correlated with the Dst index in very strong geomagnetic storms. Most of CMEs causing very strong storms (Dst ${\leq}$-200nT) are found to have large Earthward direction parameter $({\geq}0.6)$, small eccentricity, bo distance and central angle parameters $(E{\leq}0.4,\;{\Delta}X\;and\;sin\;{\theta}{\leq}0.2)$. These directional parameters are very important parameters that control the geoeffectiveness of very fast front-side halo CMEs.

Automated Determination of Prostate Depth for Planning in Proton Beam Treatment (양성자치료에서의 종양의 위치 및 깊이 검출 자동화 시스템에 관한 연구)

  • Cheong, Min-Ho;Yoon, Myong-Geun;Kim, Jin-Sung;Shin, Dong-Ho;Park, Sung-Yong;Lee, Se-Byeong
    • Progress in Medical Physics
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    • v.20 no.3
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    • pp.180-190
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    • 2009
  • Depth of prostate volume from the skin can vary due to intra-fractional and inter-fractional movements, which may result in dose reduction to the target volume. Therefore we evaluated the feasibility of automated depth determination-based adaptive proton therapy to minimize the effect of inter-fractional movements of the prostate. Based on the center of mass method, using three fiducial gold markers in the prostate target volume, we determined the differences between the planning and treatment stages in prostate target location. Thirty-eight images from 10 patients were used to assess the automated depth determination method, which was also compared with manually determined depth values. The mean differences in prostate target location for the left to right (LR) and superior to inferior (SI) directions were 0.9 mm and 2.3 mm, respectively, while the maximum discrepancies in location in individual patients were 3.3 mm and 7.2 mm, respectively. In the bilateral beam configuration, the difference in the LR direction represents the target depth changes from 0.7 mm to 3.3 mm in this study. We found that 42.1%, 26.3% and 2.6% of thirty-eight inspections showed greater than 1 mm, 2 mm and 3 mm depth differences, respectively, between the planning and treatment stages. Adaptive planning based on automated depth determination may be a solution for inter-fractional movements of the prostate in proton therapy since small depth changes of the target can significantly reduce target dose during proton treatment of prostate cancer patients.

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A Study on the Heat Release Characteristics of Fire Load for Performance Based Design of Multiplexes: A Focus on the Heat Release Rate and Fire Spread Rate of Cinema Seats (복합영상관의 성능위주설계를 위한 가연물의 연소발열특성 연구: 객석의자의 열발생률 및 연소확산속도를 중심으로)

  • Nam, Dong-Gun;Jang, Hyo-Yeon;Hwang, Cheol-Hong;Lim, Ohk-Kun
    • Fire Science and Engineering
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    • v.34 no.1
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    • pp.11-17
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    • 2020
  • As performance-based design (PBD) has a direct impact on evacuation safety assessments, designing fire scenarios based on real fire tests is essential. To improve the reliability of the PBD for fire safety in multiplexes, information on fire behavior, such as heat release rate (HRR) and fire spread rate, are provided in this study by conducting a standard fabric flammability test. To this end, several chairs were arranged in a pattern that resembled a theater-style seating. The peak HRR and heating value per unit mass for each chair ranged from 415 kW to 988 kW and 15.2 MJ/kg to 23.8 MJ/kg, respectively. The heating values per unit mass of the new and old chairs were 23.6 MJ/kg and 16.7 MJ/kg, respectively. As the quantity of plastic and cushioning materials in the new chairs was more than that of the old ones, the new chairs were more vulnerable to fire hazards. Furthermore, when the chairs were arranged in a line, the fire spread rate was observed to be 0.39-0.42 m/min, regardless of the ignition location. Finally, a fire growth curve showing the peak HRR and fire spread rate was also demonstrated.

한국 가정과 교육과정의 현황과 과제

  • 윤인경
    • Proceedings of the KHEEA Conference
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    • 2002.08a
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    • pp.5-19
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    • 2002
  • 재한국, 1995년제일차출대국가제정적가정과교육과정. 지후, 한국적가정과교육과정경마료7차적수정여개혁과정. 재차과정중, 가정과정불단지추극출신, 기과목명칭재변화, 필수자선 등 선과성질야재변화, 과치함축, 여기술과정합. 이차, 가정과변위남녀생공수적과목, 저취순응료사회발전적수요. 종한국적교육과정래간, 1년급도10년급시국민공용기본교육계단, 11년급도12년급시자선교육계단. 거차, 가정과교육과정적접배위여하 : 소학(5~6학년)위실과, 중학화고중(7~10학년)위"기술.가정", 고중(11~12학년)위"가전과학". 장종2003년개시실시적가정과과시안배위여하 : 소학각2과시, 7~12학년시각2.3.3.3과시, 11~12학년위6개등차. 최근, 청소년문제, 교육환경, 상시인성, 가정파양, 소비과잉, 학대아동, 등사회문제도근가정생활유착밀절적연계, 인차, 재반지교육중, 가정교육응수중시. 단시, 실제상병불시여차. 작위교육주체적교사화부모도몰유인식도저개실정. 인차, 가정학자여교사유심요주근지거연구가정교육. 우기시, 유필요근중국, 일본, 등저사아주국가호상교류화합작적과정중거탐색가정교육적안정발전. 하면파미래가정학육발전적방향건의여하 : 1) "가정" 과시이가정과위연구대상적가정학적독립적연구요영역. 가정경적연구감상시 "가정", 타이가정생활질량적제고위기연구목적. 인차, 재가정교육중, 과목적명칭명명위 "기술. 가정", "가정일반". "가사" 시부합리적. 이응위 "가정" 2) 가정교육웅사중시성각색적변환, 직업적인직변고적각도출발, 사소학도고중분개위필수화선수과, 유남녀생공수. 3) 가정과과시재축점축단. 도시유우교육과정적축단이인기적피면불료적현상. 단시고 여가정과시실천, 실험성과목응보장기최저적과시, 최기마필수유지현재적과시. 4) 향래, 한국적가정교육과정기이가정과위기본철학배경화리념, 우급시파국가교육과정적배경화이념, 가정학적발전동태반영재교육과정중, 즉강조즘요교. 단시, 경력료반복적변혁지후, 최근, 각중시즘양거배양학생적십 요 양적능력여가치. 인차, 가정교육파교육목라방재즘루거제고가정생활적질량, 즘루거호조화가정생활화직업생활, 즘양거개발합리지해결화실천가정생활적가치관. 5) 최근, 가정교육파교육방향화목라방재거배양학생작위독립적개인, 작위가족적성원, 작위사회성원래주인생도로적능력. 인차, 가정교육이인적생활위중심. 우거섭급학생재성장과정중소우도적문제,재거포괄재가정화사회생활중소우도적문제. 즉거배양해결가정생활중소우도적소유적 문종적종합능력. 6) 가정과재교학방법화교학평개상, 응채용실험, 실습, 관찰 등방식, 응반체험성, 실천성경험. 위차, 응필편기험적실험, 실습설비. 7) 확정교육과정편제적치후, 응제고일반교육학자적참여율, 가정교육학자응적극참여 제정교청정책적유관교육적각종위원회. 재제정정책적과정중각진소능, 적극제출건고성적의황. 8) 한, 중, 일 삼국권원층립가정교육과정도작사, 위삼국교육과정적량호발전주공헌.

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The Ultra-Centrifuge Rotordynamics (초고속 원심분리기의 회전체동역학 설계)

  • 이안성;김영철;박종권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1996.10a
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    • pp.319-323
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    • 1996
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Analysis of characteristics of natural resins using organic residue analysis organic materials attached on wooden coffins from Singok-dong Site, Uijeongbu (유기잔존물 분석을 활용한 천연 수지 특성 분석 - 의정부 신곡동 유적 출토 목관 부착 유기물을 중심으로 -)

  • YUN, Eunyoung
    • Korean Journal of Heritage: History & Science
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    • v.54 no.4
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    • pp.78-89
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    • 2021
  • Organic residues analysis is an analysis method that reveals the types of organic material samples by using the characteristic that main components constituting substances are different depending on the species of animals and plants. In this study, scientific analysis of the organic residues attached to wood coffins in the Joseon Dynasty Hoemyo excavated from the site of Singok-dong, Uijeongbu was used to identify the types of remnants and to use them as information to restore the uses of organic materials and the way they lived in the past. As a result of FT-IR analysis of the residue attached to the inside of the wood, it was estimated to be a natural plant resin material. In addition, as a result of analysis by GC-MS to confirm the characteristic factors of natural resins, diterpenoids (abietane) and pimaran (pimarane), such as dehydroabietic acid and pimaric acid (diterpenoid) compounds, and saturated and unsaturated fatty acid components were detected together. Diterpenoid compounds are components mainly found in Pinaceae resins. It is confirmed in the literature that rosin, a representative material of Pinaceae resin, was used as an adhesive material. Considering the situation where an organic material remained at the joint of the wood, the organic material attached to the wood is judged to be an adhesive material made of Pinaceae resin. In addition, the fatty acid component detected together is a component derived from plant oil, and it is presumed to be made by mixing rosin and oil as recorded in previous studies. This study confirms that organic residues remain in the burial environment without losing their characteristics. It is expected that scientific analysis of organic residues will be conducted in the future to accumulate information necessary for the interpretation of past living culture.

Effect of a Maepsi Exercise Program on the Ground Reaction Force Variables of middle-aged women during Gait (8주간의 맵시 운동 프로그램이 중년여성들의 보행 동작 시 지면반력 요인들에 미치는 영향)

  • Park, Hui-Jun;Kwon, Moon-Seok
    • Journal of the Korean Applied Science and Technology
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    • v.38 no.3
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    • pp.762-770
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    • 2021
  • The purpose of this study was to analyze the effect on the vertical ground reaction force, the elapsed time, and the center of pressure factors during gait by maepsi exercise program, which is a whole body exercise, to middle-aged women for 8 weeks. A total of 25 subjects participated in this study, 13 in the exercise group(age, 41±4.4 years; heigh, 162.5±5.8cm; weight, 57.8±6.7kg; body mass, 21.9±2.4kg/m2) and 12 in the control group(age, 41.1±5.6 years; height, 160.9±5.5 cm; weight, 576.2±8.1 kg; body mass, 21.7±2.9 kg/m2). In the exercise group, the maepsi exercise program consisting of 7 areas, 23 types and 77 movements, was conducted 3 times a week for 8 weeks. Two-way repeated measures ANOVA was performed to verify the ground reaction force factors during gait, and the post-test was analyzed with bonferroni adjustment(a=.05). In the exercise group, compared to the control group, the exercise group showed higher values than the control group in the elapsed time to FMWA and FPO, vertical ground reaction force at FMWA and FPO, and RMS factors of COP in the AP direction. Therefore, it was found that the 8-week maepsi exercise program improved the acceleration and deceleration exercise functions of middle-aged women who performed gait.

Plio-Quaternary Seismic Stratigraphy and Depositional History on the Southern Ulleung Basin, East Sea (동해 울릉분지 남부의 플라이오-제4기 탄성파 층서 및 퇴적역사)

  • Joh, Min-Hui;Yoo, Dong-Geun
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.14 no.2
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    • pp.90-101
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    • 2009
  • Analysis of multi-channel seismic reflection data from the Southern Ulleung Basin reveals that Plio-Quaternary section in the area consists of nine stacked sedimentary units separated by erosional unconformities. On the southern slope, these sedimentary units are acoustically characterized by chaotic seismic facies without distinct internal reflections, interpreted as debris-flow bodies. Toward the basin floor, the sedimentary units are defined by well-stratified facies with good continuity and strong amplitude, interpreted as turbidite/hemipelagic sediments. The seismic facies distribution suggests that deposition of Plio-Quaternary section in the area was controlled mainly by tectonic movement and sea-level fluctuations. During the Pliocene, sedimentation was mainly controlled by tectonic movements related to the back-arc closure of the East Sea. The back-arc closure that began in the Miocene caused compressional deformation along the southern margin of the Ulleung Basin, resulting in regional uplift which continued until the Pliocene. Large amounts of sediments, eroded from the uplifted crustal blocks, were supplied to the basin, depositing Unit 1 which consists of debris-flow deposits. During the Quaternary, sea-level fluctuations resulted in stacked sedimentary units (2-9) consisting of debris-flow deposits, formed during sea-level fall and lowstands, and thin hemipelagic/turbidite sediments, deposited during sea-level rise and highstands.

Analysis of the Factors Relating Nutritional Status in Discharging of Leukemia Patients Receiving Chemotherapy (항암화학요법을 받고 있는 혈액암 환자의 퇴원시 영양 상태와 관련한 요인 분석)

  • So, Eun-Jin;Kim, Jee-Yeon;Jung, Su-Jin;Park, Sook
    • Journal of Nutrition and Health
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    • v.43 no.1
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    • pp.26-33
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    • 2010
  • This study was performed to investigate the changes of oral diet intake during the admission period and identify the factors related with nutritional status in discharging of leukemia patients. This is a retrospective cross sectional study on 46 leukemia patients receiving chemotherapy at the Catholic University of Korea Seoul St. Mary's Hospital from July to September 2009. The patients' charts were surveyed on the general characteristics and factors relating chemotherapy. The calorie count method was used to investigate diet intake during admission period. Multivariate logistic regression analysis was used to identify possible confounding factors. A p < 0.05 was considered statistically significant. The mean age was $42.8\;{\pm}\;14.6$ years and the average length of stay was $30.4\;{\pm}\;7.0$ days. The incidence of malnourished patients was 60.9% in discharging. There was a significant difference in chemotherapy sessions and chemotherapy period between well-nourished and malnourished patients. The average energy intake was 1,525.9 kcal in well-nourished patients and 1,143 kcal in malnourished patients, which was significant different. From repeated measures ANOVA test, the changes of oral intake during admission period were significant by groups. In addition, there were significant differences in oral intake according to each period between well-nourished and malnourished patients. In multivariate logistic regression analysis, both the ratio of total oral energy intake to recommended energy intake and chemotherapy sessions were significantly associated with nutritional status in discharging. The results of this study could be used to establish a protocol of nutritional management for leukemia patients receiving chemotherapy.