• 제목/요약/키워드: Mass loss

검색결과 1,649건 처리시간 0.025초

Inner Circumstellar Ring of Galactic Luminous Blue Variable G26.

  • Lee, Jae-Joon
    • 천문학회보
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    • 제43권2호
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    • pp.51.4-51.4
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    • 2018
  • Luminous blue variables (LBVs) are luminous evolved massive stars (thus with very large initial masses) typified by their irregular variabilities, which are sometimes associated with eruptive mass loss. G026.47+0.02 is one of the known Galactic LBV surrounded by large circumstellar shell (r~1') detected in far IR. In this presentation, we report the identification of another shell of smaller radii (r~20") indicating that the central star experienced multiple episodes of eruptions. We present detailed multi-wavelength study of the inner shell in near IR and sub-mm, with which we reconstruct its mass-loss history.

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차음재의 음향투과손실 측정에 Two-Microphone Impedance Tube Method의 적용과 한계 (The Limit and Application of Two-microphone Impedance Tube Method to the Sound Transmission Loss Measurement of Sound Isolation Materials)

  • 이승;안민홍;이동훈
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.883-888
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    • 2002
  • This study describes the limit and application of the two-microphone impedance tube method to the sound transmission loss measurement of several sound isolation materials with different physical properties. For the sound isolation materials having small flexural rigidity, it is shown that the two-microphone impedance tube method is validated to practically measure the sound transmission loss. For the sound isolation materials having large flexural rigidity, on the other hand, it is found that the two-microphone impedance tube method is no longer valid to measure the sound transmission loss because the regions of resonance and mass law are moved into the higher frequencies. In addition, in order to accurately measure the sound transmission loss of sound isolation materials, their size should be decided based on the consideration of the effect of acoustic excitation on their vibration response.

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가스 터빈 블레이드 냉각 성능 향상을 위한 경사요철의 단락 효과 (An Investigation of Angled Discrete Rib-Turbulators for Cooling Enhancement of Gas Turbine Blades)

  • 우성제;이세영;조형희
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.782-789
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    • 2001
  • Local heat/mass transfer and friction loss in a square duct roughened with various types of continuous and discrete rib turbulators are investigated. The combined effects of the gap flows of the discrete ribs and the secondary flows are examined for the purpose of the reduction of thermally weak regions and the promotion of the uniformity of heat/mass transfer distributions as well as the augmentation of average heat/mass transfer. The rib-to-rib pitch to the rib height ratio (p/e) of 8 and the rib angles of 90 and 60 deg are selected with $e/D_{h}=0.08$. The vortical structure of the secondary flows induced by the parallel angled arrays are quite distinct from that induced by the cross angled arrays. This distinction influences on heat/mass transfer and friction loss in all the tested cases. The gap flows of the discrete ribs reduce the strength of the secondary flows but promote local turbulence and flow mixing. As a result, the fairly uniform heat/mass transfer distributions are obtained with two row gaps.

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Factors Affecting Blood Loss During Thoracoscopic Esophagectomy for Esophageal Carcinoma

  • Urabe, Masayuki;Ohkura, Yu;Haruta, Shusuke;Ueno, Masaki;Udagawa, Harushi
    • Journal of Chest Surgery
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    • 제54권6호
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    • pp.466-472
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    • 2021
  • Background: Major intraoperative hemorrhage reportedly predicts unfavorable survival outcomes following surgical resection for esophageal carcinoma (EC). However, the factors predicting the amount of blood lost during thoracoscopic esophagectomy have yet to be sufficiently studied. We sought to identify risk factors for excessive blood loss during video-assisted thoracoscopic surgery (VATS) for EC. Methods: Using simple and multiple linear regression models, we performed retrospective analyses of the associations between clinicopathological/surgical factors and estimated hemorrhagic volume in 168 consecutive patients who underwent VATS-type esophagectomy for EC. Results: The median blood loss amount was 225 mL (interquartile range, 126-380 mL). Abdominal laparotomy (p<0.001), thoracic duct resection (p=0.014), and division of the azygos arch (p<0.001) were significantly related to high volumes of blood loss. Body mass index and operative duration, as continuous variables, were also correlated positively with blood loss volume in simple linear regression. The multiple linear regression analysis identified prolonged operative duration (p<0.001), open laparotomy approach (p=0.003), azygos arch division (p=0.005), and high body mass index (p=0.014) as independent predictors of higher hemorrhage amounts during VATS esophagectomy. Conclusion: As well as body mass index, operation-related factors such as operative duration, open laparotomy, and division of the azygos arch were independently predictive of estimated blood loss during VATS esophagectomy for EC. Laparoscopic abdominal procedures and azygos arch preservation might be minimally invasive options that would potentially reduce intraoperative hemorrhage, although oncological radicality remains an important consideration.

중고도비만 환자에 대한 가미태음조위탕의 활용: 후향적 차트 리뷰 (Gamitaeeumjowee-tang for Patients with Class II or III Obesity: A Retrospective Chart Review)

  • 이유빈;이아름;손민주;안시현;한지연
    • 한방비만학회지
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    • 제24권1호
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    • pp.54-67
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    • 2024
  • Objectives: The purpose of this study was to evaluate changes in body weight and blood pressure and also analyze adverse events after weight loss program using Gamitaeeumjowee-tang in patients with class II or III obesity, considering for metabolic and bariatric surgery. Methods: A retrospective chart review was conducted on class III obesity or class II obesity patients with comorbidities, who participated in 24-week weight loss program using Gamitaeeumjowee-tang (n=54). The analysis included changes in body weight, body mass index, fat mass, skeletal muscle mass, waist-hip ratio and blood pressure before and after the program. And also calculated the proportion of patients who lost more than 5%, 10%, and 15% of their initial weight. Adverse events were assessed by causality, severity and system-organ classes. Results: After the weight loss program, body weight decreased 12.21±6.43 kg (12.77%), and BMI decreased 4.61±2.25 kg/m2 (12.75%) on average (P<0.05). The 90.7% of the subjects lost more than 5% of their weight, 68.5% lost more than 10%, and 35.1% lost more than 15% of their weight. Blood pressure significantly decreased 11.04±14.53 mmHg in systolic and 7.28±11.89 mmHg in diastolic on average (P<0.05). The 97% of adverse events were mild, and 75% were evaluated as 'unlikely' in the causality evaluation. Conclusions: The results of this study, the weight loss program using Gamitaeeumjowee-tang showed significant weight loss and blood pressure reduction in patients with class III obesity or class II obesity with comorbidities, without serious adverse events. Well-designed clinical studies are recommended for the future.

가미생화탕과 가미보허탕의 연속 투여가 산후 체중정체와 체성분 변화에 미치는 영향 (The effect of Kami-Saenghwatang and Kami-Bohertang to postpartum weight retention)

  • 하정일;김동일
    • 대한한방부인과학회지
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    • 제20권2호
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    • pp.164-175
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    • 2007
  • Purpose: The purpose of this study was to investigate the relationships between the herbal medicines used for women in puerperium on postpartum care, Kami-Saenghwatang(SHT) and Kami-Bohertang(BHT) and postpartum body composition change. We also examined the influence of gestational age, the number of parity and the route of delivery for gestational weight gain and postpartum weight loss. Methods: 239 women followed by postpartum care center. Variety factor s were conformed and then checked body composition analysis. 8 weeks later, we followed up body composition of 36 women among the former checked. and additionally asked the body weight of another 42 former checked women by telephone call. Results: $Mean{\pm}S.D$(standard deviation) of pre-pregnancy weight is $55.22{\pm}8.98kg$, $Mean{\pm}S.D$ of gestational maximun weight is $69.26{\pm}9.77kg$, $Mean{\pm}S.D$ of weight loss in postpartum 8 weeks(means sub-tract postpartum 1 week weight from postpartum 8 week weight) is $57.86{\pm}8.60kg$. The number of parities had corrrelation with gestational weight gain. Age, number of parities and route of delive were not significantly correlated with postpartum weight loss during 8 weeks after delivery, and also it was not correlated with body water mass, body fat mass, body mass index and body weight on postpartum 8 weeks whether they treated with SHT and BHT. conclusion: It was not correlated with body water mass, body fat mass, body mass index and body weight on 8 weeks postpartum whether they treated with SHT and BHT.

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변량계수모형을 이용한 체지방 실험자료에 관한 통계적 분석 (A statistical analysis of the fat mass experimental data using random coefficient model)

  • 조진남
    • Journal of the Korean Data and Information Science Society
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    • 제22권2호
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    • pp.287-296
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    • 2011
  • 36명의 여대생을 대상으로 체 지방 감소효과에 대한 실험을 실시하였다. 이 실험에서 처리는 매일 섭취하는 식사종류 및 양에 대한 식사일지 작성과 카메라 폰으로 찍어 실험관리자에게 전송하여 매주상담을 받는 것이다. 실험관리자는 체 지방 및 관련된 자료를 일주일마다 측정하여 8주간의 반복측정자료를 얻었다. 이 실험자료를 이용하여 혼합모형의 일종인 변량계수모형을 이용하여 추정 및 유의성 검정을 실시한 결과, 유의한 고정인자들은 처리 전체지방 값, 비만지수, 확장기 혈압, 총 콜레스테롤 및 시간이다. 처리 후 시간에 따른 체 지방 감소는 2차 함수의 관계가 성립된다. 변량인자인 개체효과와 개체와 시간과의 교호작용에서 1차 함수의 관계가 존재한다. 처리 후 시간이 지남에 따라 체 지방 량은 점점 감소하였으며, 실험실시 8주 후에는 평균 2.1kg 감소한 효과가 있음을 보여주었다.

사각 덕트 내부 열전달 향상을 위한 요철의 단락 효과 (Effects of Discrete Rib-Turbulators on Heat/Mass Transfer Augmentation in a Rectangular Duct)

  • 권혁진;우성제;조형희
    • 대한기계학회논문집B
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    • 제24권5호
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    • pp.744-752
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    • 2000
  • The influence of arrangement and length of discrete ribs on heat/mass transfer and friction loss is investigated. Mass transfer experiments are conducted to obtain the detailed local heat/mass transfer information on the ribbed wall. The aspect ratio (width/height) of the duct is 2.04 and the rib height is one tenth of the duct height, such that the ratio of the rib height to hydraulic diameter is 0.0743. The ratio of rib-to-rib distance to rib height is 10. The discrete ribs were made by dividing each continuous rib into 2, 3 or 5 pieces and attached periodically to the top and the bottom walls of the duct with a parallel orientation The combined effects of rib angle and length of the discrete ribs on heat/mass transfer ae considered for the rib angles $({\alpha})\;of\;90^{\circ}\;and\;45^{\circ}$. As the number of the discrete ribs increases, the uniformity of the heat/mass transfer distributions increases. For $(\alpha})=90^{\circ}$, the heat/mass transfer enhancement with the discrete ribs is remarkable, while the heat/mass transfer performances are slightly higher than that of the transverse continuous ribs due to the accompanied high friction loss penalty. For $(\alpha})=90^{\circ}$, the average heat/mass transfer coefficients and the heat/mass transfer performances decrease slightly with the discrete ribs compared to the case of the angled continuous ribs.

The effect of simulated acid rain on microbial community structure in decomposing leaf litter

  • Cha, Sangsub;Lim, Sung-Min;Amirasheba, Bahitkul;Shim, Jae-Kuk
    • Journal of Ecology and Environment
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    • 제36권4호
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    • pp.223-233
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    • 2013
  • Acid deposition is one of the most serious environmental problems in ecosystems. The present study surveyed the effects of simulated acid rain on leaf litter mass loss and microbial community in the decomposing leaf litter of Sorbus anifolia in a microcosm at $23^{\circ}C$ and 40% humidity. Microbial biomass was measured by substrate-induced respiration (SIR) and phospholipid fatty acids (PLFAs), and the microbial community structures were determined by composition of PLFAs at each interval of decomposition in litter sample and at each pH treatment. The microbial biomass showed peaks at mid-stage of decomposition, decreasing at the late stage. The leaf litter mass loss of S. anifolia decreased with decreasing pH during early and mid-decomposition stages; however the mass loss becomes similar between pH treatments at late-decomposition stage. The acidification remarkably lowers the microbial biomass of bacteria and fungi; however, microbial diversity was unchanged between pH treatments at each stage of litter decomposition. With changes of decomposition stage and pH treatment there were considerable differences in replacement and compensation of microbial species. Fungi/bacteria ratio was considerably changed by pH treatment. The PLFA profile showed significantly larger fungi/bacteria ratio at pH 5 than pH 3 at the early stage of decomposition, and the difference becomes smaller at the later decomposition stage. At low pH, pH 3 and pH 4, the fungi/bacteria ratios were stable according to the litter decomposition stages. Simulated acid rain caused decreases of 10Me17:0, 16:1${\omega}$7c, 18:1${\omega}$7, 15:0, but increase of 24:0. In addition, litter mass loss showed significant positive correlation with microbial biomass measured by SIR and PLFA on the decomposing leaf litter.

OPTIMZATION OF A PIN FIN BASED ON THE INCREASING RATE OF HEAT LOSS

  • Kang, Hyung-Suk
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제12권1호
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    • pp.25-32
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    • 2008
  • A pin fin is optimized based on the increasing rate of heat loss by using a two-dimensional analytic method. The optimum heat loss, corresponding optimum thermal resistance and fin length are presented as a function of the fin base thickness, convection characteristic numbers ratio, fin outer radius and ambient convection characteristic number. One of the results shows that both the optimum heat loss and fin length decrease linearly whereas the optimum thermal resistance increases very slightly with increase of the fin base thickness.

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