• Title/Summary/Keyword: CENTER OF MASS(CM)

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The Kinematic Analysis of the Rybalko Motion on the Horizontal Bar (철봉 리발코(Rybalko) 동작의 운동학적 분석)

  • Lee, Byoung-Won
    • Korean Journal of Applied Biomechanics
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    • v.16 no.1
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    • pp.109-117
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    • 2006
  • The purpose of this study was done in order to investigate the Kinematical variables of the Rybalko motion on the Horizontal bar using the 3-dimensional cinematographic method. For this study, three excellent athletes take part in a 2003 Daegue universid game were chosen. The subject,s Rybalko motion was filmed with S-VHS camera at the speed of 60 fields per second and digitized the each fields. And the Kwon3D 3.1 version program was employed to obtain 3-dimensional data. As a result of this study. 1. A total time spent for performing Rybalko skill was Mean $2.52{\pm}0.13sec$. From starting down swing to releasing right hand the Mean $0.84{\pm}0.24sec$ was taken. 2. In the event 3 of Rybalko motion, that is, the moment which the right-hand is released on the bar, the center of mass must is employed at the position above the horizontal line of bar. In this research, the average vertical displacement(z axe) of center of mass shows $47.87{\pm}3.14cm$. 3. In the event 5, that is, the moment which the right-hand is catched again on the bar, the center of mass is employed at the position before the vertical line of bar. In this research, the average horizontal displacement(z axe) of center of mass shows $47.87{\pm}3.14cm$. 4. It has been seen that, at the moment of release of right-hand, lateral variation of center of mass is 13.395cm, vertical variation of center of mass is 7.41cm Thus, it is concluded that lateral variation of center of mass should be reduced for high grade to be acquired. 5. It has been founded that high speed of down swing influences speed of up swing, and that, in the motion of twist, the horizontal speed is little changed.

Two Cases of Repeated Pancreatectomy for Pancreatic Cancer Developing in the Remnant Pancreas after a Resection of Pancreatic Cancer - Repeated Pancreatectomy of Pancreatic Cancer - (췌장암 절제 후 잔여췌장에 발생한 췌장암에 대한 반복절제를 시행한 2례 - 췌장암의 반복절제 -)

  • Young-Il Kim;Sang Myung Woo;Woo Jin Lee
    • Journal of Digestive Cancer Research
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    • v.1 no.1
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    • pp.43-47
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    • 2013
  • There have been very few reports related to pancreatic cancer developing in the remnant pancreas after a resection for pancreatic cancer. We report two cases of repeated pancreatectomy for second primary pancreatic cancer. A 58-year-old man with a 2.3 cm sized low attenuated pancreatic tail mass on abdomen CT scan, received a distal pancreatectomy (adenosquamous carcinoma, stage IIB) and adjuvant chemoradiotherapy. A follow-up abdomen CT scan revealed a 2.0 cm sized pancreatic head mass in the remnant pancreas at 35 months after the distal pancreatectomy. He received a pancreaticoduodenectomy and diagnosed as ductal adenocarcinoma (stage IIA). Another 62-year-old female was declared pancreatic head mass on a regular health examination. An abdomen CT scan revealed a 3.6 cm sized mixed solid and cystic mass. She received a pylorus-preserving pancreaticoduodenectomy (ductal adenocarcinoma, stage IB) and adjuvant chemoradiation therapy. At 20 months after the resection, a 1.8 cm sized ill-defined low attenuated mass developing in the tail of remnant pancreas was detected on a follow-up abdomen CT scan. The patient received a distal pancreatectomy and diagnosed as ductal adenocarcinoma (stage IIA).

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Intraventricular Cavernous Malformation Radiologically Mimicking Meningioma

  • Jin, Sung-Chul;Ahn, Jae-Sung;Kwun, Byung-Duk;Kwon, Do-Hoon
    • Journal of Korean Neurosurgical Society
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    • v.44 no.5
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    • pp.345-347
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    • 2008
  • We report a case of trigonal cavernous malformation (CM) radiologically mimicking meningioma. The computed tomographic (CT) head angiography and magnetic resonance imaging (MRI) showed a partially calcified lesion with slight contrast enhancement located in the area of the left atrium of lateral ventricle. The lesion was completely removed using microsurgery with a parieto-occipital transcortical approach. The resected mass was histologically confirmed as CM. CM should be considered as differential diagnosis in case of the atrial mass lesion due to lack of hemosiderin ring characteristically seen other seated CM.

A Changing Pattern of Isotope Scan of the Midline Ectopic Thyroid - A Case Report - (정중선 이소성 갑상선에서 주사상의 변화 추적 - 증례보고 -)

  • Kim, Kap-Tae;Kim, Wan-Sub;Chung, Eul-Sam
    • Advances in pediatric surgery
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    • v.2 no.2
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    • pp.133-137
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    • 1996
  • A 17 month-old girl presented in the pediatric clinic on November 27th, 1990 with a neck mass. The mass was 2 cm in diameter, firm in consistency and movable on the upper pole of the thyroid cartilage in the midline. The technetium thyroid scan showed a hot reactivity at the compatible site of the mass, but no other radioactivity in either site of the normal thyroid positions. At her second visit on January 23th, 1996, the mass had enlarged up to 3.5cm in diameter in the same location of the neck. The follow up thyroid scan revealed a walnut sized, snowman-like radioactivity. One of the snowman-like double images seemed to be a lingual ectopic thyroid and the other a midline ectopic thyroid remnant in the infrahyoid level. This interpretation was supported by the computed tomography of the neck, which showed a ligual mass in the foramen cecum area and an another mass in the anterior comis-sure of the larynx in the mildline. Thyroid function test was normal except a slightly increased TSH. As a result of this changing pattern of thyroid radioactive images, a case of a lingual thyroid as well as another midline ectopic thyroid tissue at the infrahyoid level is reported.

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Deposition of Aerosols on Leaves in a Cool-temperate Larch Forest in Northern Hokkaido, Japan

  • Tatsuya, Fukazawa;Naoto, Murao;Hisashi, Sato;Masahiro, Takahashi;Masayuki, Akiyama;Takashi, Yamaguchi;Izumi, Noguchi;Hiroyuki, Takahashi;Chikara, Kozuka;Rei, Sakai;Kentaro, Takagi;Yasumi, Fujinuma;Nobuko, Saigusa;Kazuhide, Matsuda
    • Asian Journal of Atmospheric Environment
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    • v.6 no.4
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    • pp.281-287
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    • 2012
  • Aerosol concentrations at the CC-Lag site in the Teshio Experimental Forest increased from winter to spring and sometimes showed extremely high values associated with Kosa and/or forest-fire events. The range and mean of the mass concentrations of aerosol chemical species were as follows: total particulate mass, 1.2-29, 5.0; elemental carbon, 0.061-2.2, 0.43; organic carbon, 0.059-3.5, 0.79; and sulfate, 0.12-6.2, 1.8 ${\mu}g/m^3$. The total masses of the deposited particles on hybrid larch and on bamboo leaves were approximately 35 and 30 ${\mu}g/cm^2$, respectively. The amounts of soil particles on the leaves were 6 ${\mu}g/cm^2$ for the upper part of hybrid larch, 2 ${\mu}g/cm^2$ for the lower part of hybrid larch, and 1 ${\mu}g/cm^2$ for Sasa bamboo leaves. The amounts of deposited black carbon were 2.3 ${\mu}g/cm^2$ for the upper part of hybrid larch, 0.6 ${\mu}g/cm^2$ for the lower part of hybrid larch, and 0.2 ${\mu}g/cm^2$ for Sasa bamboo leaves. Half of the total deposited particular mass was attached on the hybrid larch; however, most of the total deposited mass was adhered on the Sasa bamboo leaves. Regardless of the species, there tend to be more deposited particles on the leaves in the upper part than in the lower part, with only a few meters height difference. Comparing the composition of the deposited particles to that of the atmospheric aerosols without any size cut, the fractions of water-soluble material sulfate and sea salt in the deposited aerosols were about one tenth and one hundredth lower than that in the aerosols, respectively. On the basis of the measured concentration and the deposited amount on leaves, the deposition velocity of black carbon was estimated to be approximately 0.5 cm/s.

Effect of Balustrade Heights and Blanket Types on Mechanism of Falling Accident during Shaking-Off the Dust of the Blanket from Balcony

  • Hyun, Seunghyun;Ryew, Checheong
    • International journal of advanced smart convergence
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    • v.9 no.2
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    • pp.38-48
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    • 2020
  • The shaking-off the dust from balustrade of higher stories may cause the higher risk of falling accident rate. Main purpose of this study was to quantify an effect of balustrade heights and blanket types on possibility of falling accident relative to one's motor controllability during shaking-off the dust of the blanket from balcony. Female participants, who consisted of total 10 under condition of balustrade height of 3 kinds (90 cm, 110 cm, 130 cm) and blanket types (0.4 kg, 1.6 kg, 3 kg, 200230 cm), performed repetitively the task of shaking-off the dust of the blanket. Vertical position and velocity of center of mass due to increase of blanket weigh in case of balustrade height of 90 cm was increased, but vertical ground reaction force was decreased swiftly. That is, the higher balustrade height was, the less distance difference between center of mass and center of pressure was.

Predicting the seismic behavior of torsionally-unbalanced RC building using resistance eccentricity

  • Abegaz, Ruth A.;Kim, In-Ho;Lee, Han Seon
    • Structural Engineering and Mechanics
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    • v.83 no.1
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    • pp.1-17
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    • 2022
  • The static design approach in the current code implies that the inherent torsional moment represents the state of zero inertial torsional moments at the center of mass (CM). However, both experimental and analytical results prove the existence of a large amount of the inertial torsional moment at the CM. Also, the definition of eccentricity by engineers, which is referred to as the resistance eccentricity, is defined as the distance between the center of mass and the center of resistance, which is conceptually different from the static eccentricity in the current codes, defined as the arm length about the center of rotation. The difference in the definitions of eccentricity should be made clear to avoid confusion about the torsion design. This study proposed prediction equations as a function of resistance eccentricity based on a resistance eccentricity model with advantages of (1) the recognition of the existence of torsional moment at the CM, (2) the avoidance of the confusion by using resistance eccentricity instead of the design eccentricity, and (3) a clear relationship of applied inertial forces at the CM and resisting forces. These predictions are compared with the seismic responses obtained from time-history analyses of a five-story building structure under moderate and severe earthquakes. Then, the trend of the resistance eccentricity corresponding to the maximum edge drift is investigated for elastic and inelastic responses. The comparison given in this study shows that these prediction equations can serve as a useful reference for the prediction in both the elastic and the inelastic ranges.

A primo vessel-like structure in a dog with inflammatory pseudotumor

  • Cho, Sung-Jin;Hong, Sun-Hwa;Han, Sang-Jun;Kim, Ok-Jin
    • Korean Journal of Veterinary Service
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    • v.35 no.1
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    • pp.77-82
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    • 2012
  • Inflammatory pseudotumor (IPT) is a term defining a mass characterized microscopically by a proliferation of bland mesenchymal spindle cells infiltrated by diffuse mixed inflammatory cells with a predominance of plasma cells and lymphocytes. Here, we show the primo vessel-like structure of the primo-vascular system (PVS) in a dog with IPT. A 6-years old male Mongrel dog was diagnosed with an abnormal mass (diameter 5.5 cm, weight 22 g) near left preputial area. The dog was submitted to the surgical detectomy of the mass. During the surgical operation, we observed primo vessel-like material. After fixations, the masses appeared macroscopically as lipoid-like, firm, white to grey masses, measuring $5{\times}8cm$. Histologically, cellular infiltration into the muscular layers was frequently seen. The mesenchymal proliferation remained the main component of the mass and was composed of myofibroblastic-like spindle cells characterized by globular, irregular nuclei containing open chromatin and a prominent nucleolus. On the basis of the histopathologic lesions, the subcutaneous mass was diagnosed as IPT. Also, we detected a primo vessel-like structures in some areas of the IPT tissues. These were observed as novel thread-like structures and bundle of tubular structures. To our knowledge, this report is the first case of primo vessel-like structure in a dog with IPT.

Kinematic Analysis of Double Backward Somersault on the Parallel Bars (평행봉 2회전 뒤돌아 무릎 구부려 내리기 동작의 운동학적 분석)

  • Lee, Jong-Hun;Lee, Yong-Sik
    • Korean Journal of Applied Biomechanics
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    • v.14 no.1
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    • pp.27-40
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    • 2004
  • The purpose of this study was to provide basic data for improving athletic performances by analyzing the kinematic variables of the Double Backward Somersault on the Parallel Bars through the 3D motion analysis. The subjects in this study were 5 male gymnasts who were ranked as national athletes. The results are as follows. 1. A total time(Mean Time) of performance showed $2.72{\pm}0.82\;sec$. and flight time to landing after releasing was 0.87sec.(mean). In order to perform better stable flying movement, the flight time should be increased. 2. In the change of velocity of the center of mass, when the increasing ascension velocity of the upper point was high, the position in the top point was high on releasing. 3. In the position variable of the center of mass, the mean of upper-bottom position in horizontal posture was $242.1{\pm}6.5cm$, $232.8{\pm}6.4cm$ in releasing, and $265.0{\pm}5.6cm$ in the highest point. This result is explained that the position of center of mass can be raised by using elastic power when wrist raised the bar in the releasing movement. 4. The angle of shoulder joint was $271.1{\pm}14.0$. Such a big angle influences a negative effect on the releasing velocity, because trunk is not a position in the enough vertical direction. 5. The ankle of hip joint in hand-standing was $191.1{\pm}5.9$, $118.8{\pm}5.3$ in releasing, and $122.3{\pm}5.3$ in taking on. Therefore, the result suggests that trunk should be straightly raised in taking on.

A Study on the Flame Behavior of Whirl Eire and Pool Fire (Whirl Fire와 Pool fire의 화염 거동에 관한 연구)

  • Oh Kyu-Hyung;Kang Youn-Ok;Lee Sung-Eun
    • Journal of the Korean Society of Safety
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    • v.19 no.3 s.67
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    • pp.45-50
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    • 2004
  • 4-panel of 1m height and 45cm width were fixed on the $40cm{\times}40cm$ bottom plate and the opening of the panel comer was 5cm. Diameter of stainless vessel is loom and its height is 2cm and it located at the center of the bottom plate. 78mL liquid fuel was filled in the vessel and its depth was 1cm. Flame temperature was measured with K type thermocouple, and radiation heat of flame was measured with heat flux meter. Flame height and its behavior was visualized with video camera. and mass burning rate was measured by fuel combustion time. According to the development of fire, flame swirling was begin. From the experiment the mass burning rate was larger and the height of flame was higher than the usual pool fire flame. Flame temperature and heat flux also increased far more than the pool fire. Consequently the swirling air flow through the openings between the panel and thermal buoyance contribute to increase of heat release rate, flame length and mass burning rate.