• 제목/요약/키워드: Center of mass

검색결과 4,963건 처리시간 0.031초

Mass and energy of erupting plasma associated with a coronal mass ejection in X-rays and EUV

  • Lee, Jin-Yi;Raymond, John C.;Reeves, Katharine K.;Moon, Yong-Jae;Kim, Kap-Sung
    • 천문학회보
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    • 제40권1호
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    • pp.85.1-85.1
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    • 2015
  • We investigate the mass and energy of erupting plasma observed in X-rays and EUV, which is associated with a coronal mass ejection (CME) and an X-class flare. The erupting plasma was observed by both the X-ray telescope (XRT) on Hinode and the Atmospheric Imaging Assembly (AIA) on Solar Dynamic Observatory (SDO). We estimate the emission measures of the erupting plasma using a differential emission measure method. The plasma erupts with a loop-like structure in X-ray and EUV. We estimate the mass of erupting plasma assuming a cylinder structure. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive hot plasma. We find that the thermal conduction timescale is much shorter than the duration of the eruption. This result implies that additional heating during the eruption may be required to explain the hot plasma observations in X-rays.

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Mass transfer in cross-flow dialyzer with internal recycle

  • Yeh, Ho-Ming;Chen, Chien-Yu
    • Membrane and Water Treatment
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    • 제4권4호
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    • pp.251-263
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    • 2013
  • The internal reflux effect on dialysis through the retentate phase of a countercurrently cross-flow rectangular module is investigated. Theoretical analysis of mass transfer in cross-flow devices with or without recycling is analogous to heat transfer in cross-flow heat exchangers. In contrast to a device without reflux, considerable mass transfer is achievable if cross-flow dialyzers are operated with reflux, which provides an increase in fluid velocity, resulting in a reduction in mass-transfer resistance. It is concluded that reflux can enhance mass transfer, especially for large flow rate and feed-concentration operated under high reflux ratio.

생식보조술을 받은 산모와 자연임신한 산모에서 임신 전 체질량지수가 임신 결과에 미치는 영향 (Impact of Prepregnancy Body Mass Index on Pregnancy Outcome in Women with a Singleton Conceived by Assisted Reproductive Technology and Spontaneously Conceived Pregnancy: A Case-Control Study)

  • 김주희;신혜숙;박보경;양광문;이영호;류현미
    • 대한간호학회지
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    • 제42권4호
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    • pp.517-524
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    • 2012
  • Purpose: To compare and confirm the impact of prepregnancy body mass index on pregnancy outcome in women with a singleton conceived by assisted reproductive technology and spontaneously conceived pregnancy. Methods: A sample of 165 and 247 pregnant women with and without assisted reproductive technology were retrospectively recruited from electronic medical charts of C hospital. Results: There were significant differences between the two groups for maternal age, paternal age, length of marriage, prepregnancy body mass index, parity, spontaneous abortion experience, and preterm delivery. A prepregnancy body mass index of ${\geq}25$ was associated with higher risk for maternal and neonatal complication in the assisted reproductive technology group. Conclusion: The results indicate that a higher prepregnancy body mass index is associated with increased risks for adverse pregnancy outcomes for women using assisted reproductive technology. So these women need appropriate care to compensate for the risk.

건강한 노인과 뇌졸중 노인의 일어서기 동작 수행 시 운동학적 특성 연구 (Kinematic Analysis of Rising from a Chair in Healthy and Stroke Subjects)

  • 유연주;임비오
    • 한국운동역학회지
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    • 제17권2호
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    • pp.103-112
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    • 2007
  • The purpose of this study was to investigate the kinematic characteristics during rising from a chair. Six stroke patients and three healthy subjects participated in the study. Three dimensional kinematic analysis was used to get the duration, center of mass, and lower extremity angle. The stroke patients performed longer duration(0.28sec) than the healthy subjects in rising from a chair. The stroke subjects stayed longer time than the healthy subjects did in phase 2(From the initiation of knee extension to the reversal of trunk flexion to trunk extension)(t=-1.01, p=.04). The healthy subjects showed longer time than the stroke subjects in phase 3(from the reversal of trunk motion to extension to full standing position). The healthy subjects displayed larger value of center of mass in anterioposterior direction than stroke subjects(t=5.79, p=0.05). The center of mass in the mediolateral direction did not change during the completion of movement. However, the center of mass in the anterioposterior direction began to increase throughout the completion of movement. The center of mass in the vertical direction increased extensively in phase 3. The significant difference was not found in the maximum dorsiflexion in ankle, the initiation angle of knee, and the minimum angle of hip between stroke and healthy subjects. Even though statistical results did not show any significant angle difference in the lower extremity, the patterns of the change in the knee and hip angle during rising from a chair were different. The stroke subjects showed smaller angle of knee extension than the healthy subjects in phase 3. The stroke subjects flexed their trunk more than the healthy subjects in phase 2.

비골골절 정복술 후 커진 지방육아종의 치험례 (Enlarged Lipogranuloma after Closed Reduction of Nasal Bone Fracture: A Case Report)

  • 이지원;최재일;하원;양완석;김선영
    • 대한두개안면성형외과학회지
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    • 제13권1호
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    • pp.63-67
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    • 2012
  • Purpose: Lipogranuloma is the reaction of adipose tissue to various oils, paraffin, and other hydrocarbons injected into subcutaneous tissue for cosmetic or other reasons. The authors experienced a case of sclerosing lipogranuloma on the nasal dorsum. Methods: A 42-year-old female, without a history of the injection of any foreign materials, was admitted on our hospital for a painless, irregular, and firm mass located on her nasal dorsum with step-off deformity. It was considered that the mass had developed after augmentation rhinoplasty. The size of mass had been increased after closed reduction of nasal bone fracture. On April 2011, under general anesthesia, the mass was removed by open rhinoplasty technique. In addition, a pathologic examination was performed. After the mass extirpation, dermofat graft was performed for the correction of depression deformity. Results: The histopathological findings demonstrated a Swiss cheese pattern with variably-sized vacuoles, which corresponded to lipid removed with tissue processing, and variable foreign body giant cell reaction, fat necrosis, and hyalinized fibrous tissue. The pathologic diagnosis is lipogranuloma replacing nasalis muscle. It has been considered that sclerosing lipogranuloma is caused by nerve injury during augmentation rhinoplasty and the ointment used after the closed reduction of nasal bone fracture, which infiltrated through the injured mucosa. Conclusion: During the treatment of rhinoplasty or nasal bone fracture, the nerve injury or the ointment use can lead to lipogranuloma. Therefore, careful dissection for avoidance of the nerve injury and limited use of ointment seems to be helpful in decreasing incidence of lipogranuloma.

포환던지기 동작 시 포환과 신체 무게중심의 운동학적 특성 : 한국 여자 기록보유자를 대상으로 (Kinematic Characteristics of the Thrower's COM and the Shot in Shot Put : The Woman Record Holder of Korea)

  • 이동진;조병준;이명선
    • 한국산학기술학회논문지
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    • 제13권11호
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    • pp.5148-5154
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    • 2012
  • 본 논문은 포환던지기 여자 기록보유자의 실제 경기에서 포환과 신체 무게중심의 운동학적 특성을 분석하는데 있다. 이를 위해 2대의 비디오카메라를 이용하여 촬영 한 후, 3차원 영상분석을 위해 DLT 방법을 이용하였으며, 자료 분석을 위해 Kwon3D 프로그램을 이용하였다. 그 결과는 다음과 같다. 첫째, 포환의 투사 속도와 투사 높이는 각각 13.73 m/s, 198.6 cm(신장비 119%)로 선행연구들과 비교했을 때, 최적의 수행을 한 것으로 판단되나 투사 각도는 $34^{\circ}$로 다소 작게 나타났다. 둘째, 신체 무게중심의 이동은 글라이드 구간에서 투사 방향으로의 이동이 필요하며, 딜리버리 구간에서 신체 무게중심의 상하 이동을 제어해야 한다. 셋째, 릴리즈 순간 신체 무게중심의 좌우방향과 상하방향의 흔들림 없이 정확한 타이밍에 포환이 투사되어야 한다.

두 마리의 개에서 결장 평활근종의 증례 (Colonic Leiomyoma in Two Dogs)

  • 정주현;채웅주;권도형;최민철
    • 한국임상수의학회지
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    • 제31권5호
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    • pp.430-434
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    • 2014
  • 두 마리의 개가 각각 다른 임상 증상, 저혈당증과 변비를 주증으로 내원하였다. 복부 방사선 검사에서 연조직 밀도의 크고 둥근 종괴가 하복부에서 관찰되었다. 변비를 주증으로 하는 개에서는 이 종괴로 인한 결장의 직경 감소가 관찰되었다. 복부 초음파 검사에서 이질적 에코의 크고 둥근 종괴가 한계 명료하게 관찰되며, 복강의 주요 장기와 관련이 없을 것으로 생각되었다. 탐색적 개복술에서 종괴는 결장의 장막층에서 유래한 것으로 확인되었고, 쉽게 제거되었다. 조직검사에서 평활근종으로 확인되었고, 두 마리 모두 재발 및 후유증 없이 임상 증상이 개선되었다. 결장 평활근종의 신생물딸림증후군으로 저혈당증이 발생한 증례와 결장 평활근종의 직접적인 압박으로 인한 변비가 발생한 증례를 보고한다.

이마에 발생한 석회화된 지방종 (Calcified Lipoma of the Forehead)

  • 황소민;김형도;임광열;정용휘;송제니퍼김
    • 대한두개안면성형외과학회지
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    • 제13권2호
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    • pp.156-158
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    • 2012
  • Purpose: Although lipoma is known as one of the most common soft tissue tumors, calcification in lipoma is very rare in its occurrence. This calcified lipoma has been reported by some as a result of regression of lipoma, but its genesis is not clearly known yet with various opinions being discussed regarding its possible metabolic relation to hypercalcemia or hyperphosphatemia to be considered as a regression phase of lipoma. The authors would like to present this unusual case of calcified lipoma. Methods: A 50-year-old male patient visited our hospital with complaint of an enlarging mass on his right forehead which has been acknowledged for 5 years' period. On physical examination, a mass was observed on his forehead as palpable, non-tender, mobile and firm in its consistency. Ultra sonogram examination revealed a well-demarcated mass (1.92 cm) with central echoic zone at deep layer of forehead. Mass excision and biopsy were performed subsequently. Results: According to the pathological report, the diagnosis confirmed the lipoma consisting of grown-up adipocyte and calcification. Neither growing lipoma nor relapse was observed for postoperative three years' follow-up of the patient. Conclusion: Now that the calcified lipoma was successfully removed and cured by a simple mass excision, authors hereby report the case of calcified lipoma on forehead.

무게중심을 활용한 모션 생성 기술 (Motion generation using Center of Mass)

  • 박근태;손채준;이윤상
    • 한국컴퓨터그래픽스학회논문지
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    • 제26권2호
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    • pp.11-19
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    • 2020
  • 캐릭터의 자세가 변할 때 마다 캐릭터의 무게 중심(COM) 위치도 변하게 된다. 이 때 무게 중심의 위치 변화는 걷기, 뛰기, 쭈그려 앉기 등 다양한 동작 각각에 대응되는 독자적인 패턴을 가지므로 이를 이용하면 원래 동작의 정보를 알아낼 수 있다. 본 논문에서는 캐릭터의 무게 중심의 위치 변화를 토대로 동작을 예측하는 모션 생성 기법을 제안한다. 이 방법을 이용하면 무게 중심 정보를 통해 원래 동작의 유형에 대한 별도의 라벨 없이도 다양한 동작을 생성할 수 있다. 그러므로 네트워크의 학습 및 실행을 위한 데이터셋을 만들 때 사람의 손을 거칠 필요 없이 전처리를 비롯한 모든 과정을 자동으로 진행할 수 있다. 본 논문에서 제안하는 신경망 모델은 캐릭터의 모션 이력(history) 정보와 무게 중심 정보들을 입력 받아 현재 프레임에서의 포즈 정보를 출력하며, 연속적인 시계열 모션 데이터를 다루기 위해 1차원 Convolution을 수행하는 간단한 형태의 Convolutional Neural Network(CNN)를 사용하여 학습되었다.