• Title/Summary/Keyword: Center of mass

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Experimental study of strength characteristics of reinforced broken rock mass

  • Yanxu Guo;Qingsong Zhang;Hongbo Wang;Rentai Liu;Xin Chen;Wenxin Li;Lihai Zhang
    • Geomechanics and Engineering
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    • v.33 no.6
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    • pp.553-565
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    • 2023
  • As the structure of broken rock mass is complex, with obvious discontinuity and anisotropy, it is generally necessary to reinforce broken rock mass using grouting in underground construction. The purpose of this study is to experimentally investigate the mechanical properties of broken rock mass after grouting reinforcement with consideration of the characteristics of broken rock mass (i.e., degree of fragmentation and shape) and a range of reinforcement methods such as relative strength ratio between the broken rock mass and cement-based grout stone body (λ), and volumetric block proportion (VBP) representing the volumetric ratio of broken rock mass and the overall cement grout-broken rock mass mixture after the reinforcement. The experimental results show that the strength and deformation of the reinforced broken rock mass is largely determined by relative strength ratio (λ) and VBP. In addition, the enhancement in compressive strength by grouting is more obvious for broken rock mass with spherical shape under a relatively high strength ratio (e.g., λ=2.0), whereas the shape of rock mass has little influence when the strength ratio is low (e.g., λ=0.1). Importantly, the results indicate that columnar splitting failure and inclined shear failure are two typical failure modes of broken rock mass with grouting reinforcement.

Analysis of Glycerol with Isolation of Endogenous Interferences using "Dilute and Shoot" Strategy and High-Resolution Mass Spectrometry in Human Urine for Antidoping Testing

  • Kim, Yongseok;Min, Hophil;Sung, Changmin;Park, Ju-hyung;Son, Junghyun;Lee, Kang Mi;Kim, Ho Jun;Lee, Jaeick;Kwon, Oh-Seung;Kim, Ki Hun
    • Mass Spectrometry Letters
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    • v.7 no.4
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    • pp.111-115
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    • 2016
  • Glycerol was identified and isolated from endogenous interferences during analysis of human urine using high-resolution mass spectrometry (HRMS) for doping control. Urinary sample preparation was simple; the samples were diluted with an organic solvent and then analyzed using a liquid chromatography-mass spectrometry ("dilute and shoot" method). Although the interfering ion peaks were observed at the similar retention time of glycerol, the inference could be identified by isolation with HRMS and further investigation. Thus, creatinine was identified as the endogenous interference for glycerol analysis and it also caused ion suppression resulting in the decrease of glycerol signal. This study reports the first identification and efficient isolation of endogenous interferences in human urine for "dilute and shoot" method. The information about ion suppression could be novel to prevent overestimation or a false result for antidoping analysis.

Study on anchorage effect on fractured rock

  • Wang, Jing;Li, Shu-Cai;Li, Li-Ping;Zhu, Weishen;Zhang, Qian-Qing;Song, Shu-Guang
    • Steel and Composite Structures
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    • v.17 no.6
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    • pp.791-801
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    • 2014
  • The effects of anchor on fractured specimens in splitting test are simulated by DDARF method, the results of which are compared with laboratory test results. They agree well with each other. The paper contents also use the laboratory model test. The main research objects are three kinds of specimens, namely intact specimens, jointed specimens and anchored-jointed specimens. The results showed that with the joint angle increased, the weakening effects of jointed rock mass are more obvious. At these points, the rock bolts' strengthening effects on the specimens have become more significant. There is a significant impact on the failure modes of rock mass by the joint and the anchorage.

A fatal case of acute pulmonary embolism caused by right ventricular masses of acute lymphoblastic lymphoma-leukemia in a 13 year old girl

  • Ko, Yu-Mi;Lee, Soo-Hyun;Huh, June;Koo, Hong-Hoe;Yang, Ji-Hyuk
    • Clinical and Experimental Pediatrics
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    • v.55 no.7
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    • pp.249-253
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    • 2012
  • We report a case of a 13-year-old girl with acute lymphoblastic lymphoma- leukemia, who presented with a cardiac metastasis in the right ventricle, resulting in a pulmonary embolism. At the time of her leukemia diagnosis, a cardiac mass was incidentally found. The differential diagnosis for this unusual cardiac mass included cardiac tumor, metastasis, vegetation, and thrombus. Empirical treatment was initiated, including anticoagulation and antibiotics. She underwent plasmapheresis and was administered oral prednisolone for her leukemia. Five days later, she experienced sudden hemodynamic collapse and required extracorporeal membrane oxygenation insertion and emergency surgery. These interventions proved futile, and the patient died. Pathology revealed that the cardiac mass comprised an aggregation of small, round, necrotic cells consistent with leukemia. This is the first known case of acute lymphoblastic leukemia presenting as a right ventricular mass, with consequent fatal acute pulmonary embolism. A cardiac mass in a child with acute leukemia merits investigation to rule out every possible etiology, including vegetation, thrombus, and even a mass of leukemic cells, which could result in the fatal complication of pulmonary embolism.

Contrast-enhanced US of the liver mass : Quantitative Analysis (초음파 조영제를 이용한 간종양의 유형별 소견 고찰)

  • Kim Yun-Min;Han Jung-Hwan;Kim Dong-Hwan;Park Won-Sik
    • Journal of The Korean Radiological Technologist Association
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    • v.27 no.2
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    • pp.148-156
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    • 2001
  • Ⅰ. Purpose : To determine echo value and duration of contrast enhancement of liver mass on contrast-enhanced US with Levovist by quantitative analysis. Ⅱ. Materials and Methods : Twenty three patients with liver mass were prospectively evaluated with cont

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Multilobular Osteochondrosarcoma of the Cranium in a Miniature Pinscher Dog

  • Kim, Soo-Chan;Lee, Jung-Woo;Jeong, Woo-Chang;Song, Ha-Na;Choi, Soo-Young;Choi, Ho-Jung;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.34 no.6
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    • pp.470-473
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    • 2017
  • An eight-year old neutered male miniature pinscher dog was referred with a mass on the right frontal region. Radiography, computed tomography (CT) and magnetic resonance imaging (MRI) examination were performed. Imaging results showed mineralized mass invaded frontal bone without brain parenchymal change and distant metastasis. The mass was removed mostly by surgical resection, and the dog was discharged without any complications. On the histopathological examination, the mass was diagnosed as grade I multilobular osteochondrosarcoma. Though the mass recurred after the surgical resection, the dog is still alive to date without metastasis.

Fast GPU Computation of the Mass Properties of a General Shape and its Application to Buoyancy Simulation

  • Kim, Jin-Wook;Kim, Soo-Jae;Ko, Hee-Dong;Terzopoulos, Demetri
    • 한국HCI학회:학술대회논문집
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    • 2007.02c
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    • pp.326-333
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    • 2007
  • To simulate solid dynamics,a we must com-pute the mass, the center of mass, and the products of inertia about the axes of the body of interest. These mass property computations must be continuously re-peated for certain simulations with rigid bodies or as the shape of the body changes. We introduce a GPU-friendly algorithm to approximate the mass properties for an arbitrarily shaped body. Our algorithm converts the necessary volume integrals into surface integrals on a projected plane. It then maps the plane into a frame-buffer in order to perform the surface integrals rapidly on the GPU. To deal with non-convex shapes, we use a depth-peeling algorithm. Our approach is image-based; hence, it is not restricted by the mathematical or geometric representation of the body, which means that it can efficiently compute the mass properties of any object that can be rendered on the graphics hardware. We compare the speed and accuracy of our algorithm with an analytic algorithm, and demonstrate it in a hydrostatic buoyancy simulation for real-time applications, such as interactive games.

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Generation of Water Droplet Ion Beam for ToF-SIMS Analysis

  • Myoung Choul Choi;Ji Young Baek;Aram Hong;Jae Yeong Eo;Chang Min Choi
    • Mass Spectrometry Letters
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    • v.14 no.4
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    • pp.147-152
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    • 2023
  • The increasing demand for two-dimensional imaging analysis using optical or electronic microscopic techniques has led to an increase in the use of simple one-dimensional and two-dimensional mass spectrometry imaging. Among these imaging methods, secondary-ion mass spectrometry (SIMS) has the best spatial resolution using a primary ion beam with a relatively insignificant beam diameter. Until recently, SIMS, which uses high-energy primary ion beams, has not been used to analyze molecules. However, owing to the development of cluster ion beams, it has been actively used to analyze various organic molecules from the surface. Researchers and commercial SIMS companies are developing cluster ion beams to analyze biological samples, including amino acids, peptides, and proteins. In this study, a water droplet ion beam for surface analysis was realized. Water droplets ions were generated via electrospraying in a vacuum without desolvation. The generated ions were accelerated at an energy of 10 keV and collided with the target sample, and secondary ion mass spectra were obtained for the generated ions using ToF-SIMS. Thus, the proposed water droplet ion-beam device showed potential applicability as a primary ion beam in SIMS.

Sudoriferous Cyst Adhered to Levator Aponeurosis: A Case Report (상안검 거근건막에 유착된 한선낭종의 치험례)

  • Cho, Jeong Nam;Suh, In Suck;Chung, Chan Min;Tak, Kyoung Seok;Sin, Mi Kyoung
    • Archives of Craniofacial Surgery
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    • v.9 no.2
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    • pp.93-96
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    • 2008
  • Purpose: Sudoriferous cyst usually occurs on the face, and especially on the ear and scalp as a solitary cystic mass. It is derived from the sweat glands of Moll and results from the obstruction of excretory ducts with the retention of fluid. In the eyelid, it is usually seen as small and firm vesicle arising at the eyelid margin. If it rarely occurs on the orbit, it develops from orbital ectopic epithelial cells predetermined to form glands of Moll. We experienced a case of sudoriferous cyst on eyelid which was adhered to levator aponeurosis and it disappeared when patient closed eyes. Methods: A 55-year-old women suffered palpable mass on left upper eyelid without pain that had been present for 25 years. Orbital computed tomographic finding showed a oval mass($2.1{\times}0.6{\times}0.6cm$ size) inside upper eyelid and it invaded the orbit. The mass was completely excised under general anesthesia and histopathological examination was followed. Results: Cystic mass was purple color and it was located in superiorly to tarsal plate. The mass was adhered to levator aponeurosis and levator palpabrae superioris muscle between the fat layer of post-orbital septum and the Whitnall ligament. The mass was completely excised without injury of aponeurosis and muscle. Microscopically, the lesion was a solitary cyst lined by two layers of cuboidal epithelial cells and innermost cells displaying eosinophilic cytoplasm with apical expansions. Conclusion: Sudoriferous cyst usually occurs on eyelid margin. But in this case, cystic mass occurred on upper eyelid and disappeared when patient closed the eyes because it was partially adhered to levator aponeurosis and levator palpebrae superioris muscle. Therefore, if sudoriferous cyst occurs on eyelid, it is necessary to excised the mass carefully.