• International Journal of Concrete Structures and Materials
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• v.2 no.2
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• pp.153-160
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• 2008

Fracture of prestressed concrete beams is studied with a novel and robust three-dimensional meshfree method. The meshfree method describes the crack as a set of cohesive crack segments and avoids the representation of the crack surface. It is ideally suited for a large number of cracks. The crack is modeled by splitting particles into two particles on opposite sides of the crack segment and the shape functions of neighboring particles are modified in a way the discontinuous displacement field is captured appropriately. A simple, robust and efficient way to determine, on which side adjacent particles of the corresponding crack segment lies, is proposed. We will show that the method does not show any "mesh" orientation bias and captures complicated failure patterns of experimental data well.

• Journal of Korean Neurosurgical Society
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• v.37 no.2
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• pp.154-156
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• 2005

We present a case of chondroblastoma in the thoracic vertebra. A 40-year-old patient with upper back pain and lower extremity weakness was admitted to our clinic. On neurological examination, the patient exhibited lower extremity spastic paraparesis. Magnetic resonance imaging revealed a mass infiltrating the 7th thoracic vertebra and its adjacent structures with concomitant compression of the epidural space. After right upper lung tuberculoma was resected through the transthoracic approach, T7 total corpectomy was done with anterior stabilization using a MESH cage and T7 rib bone graft. Two weeks after the first operation, remained part of vertebra was removed and posterior stabilization was performed using a pedicle screw fixation and cross linkage bar with the assistance of the navigation system. The final pathologic diagnosis of the vertebral lesion was benign chondroblastoma.

• Journal of Chest Surgery
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• v.19 no.4
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• pp.736-743
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• 1986

Thymus gland is a kind of endocrine organ which secretes thymosin and thymoprotein. There can be developed variable lesions like thymoma, thymic hyperplasia, thymic cyst, thymolipoma, and carcinoid tumor of the thymus gland. We have experienced 25 patients of thymic disease: thymoma 12, thymic hyperplasia 11, thymic cyst 1, carcinoid tumor 1. The age distribution were ranged from 3 to 66 years and the sex ratio was 1:1.8 [male to female]. Thymectomy was performed in all cases, but 3 cases with deep infiltration to the adjacent structures were not resectable completely. Malignancy [all thymoma] were 5 and the rest were benign. Two cases were died of recurrence after tumor resection. Myasthenia gravis occurred in 10 cases. Among them, 2 were thymoma and 8 were thymic hyperplasia. We could obtained the result that thymectomized cases reached 2 remission and 5 improvement. Myasthenia gravis treated medically [18 cases] had no remission and only 2 clinical improvement. In the light of these results, early radical thymectomy would be most favorable treatment in not only thymic tumor, but generalized myasthenia gravis.

• Selected Papers of The Society of Naval Architects of Korea
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• v.1 no.1
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• pp.4-14
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• 1993

A natural and an artificial harbor can exhibit frequency (or period) dependent water surface oscillations when excited by incident waves. Such oscillations in harbors can cause significant damages to moored ships and adjacent structures. This can also induce undesirable current in harbor. Many previous investigators have studied various aspects of harbor resonance problem. In the present paper, both a localized finite element method(LFEM) which is based on the functional constructed by Chen & Mei(1974) and Bai & Yeung(1974) and an integral equation method which was used by Lee(1969) are applied to harbor resonance problem. The LFEM shows computationally more efficient than the integral equation method. Our test results show a good agreement compared with other results. In the present computations, specifically two harbor geometris are treated here. The present method by LFEM can be extended to a fully three dimensional harbor problem.

• Bulletin of the Society of Naval Architects of Korea
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• v.25 no.3
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• pp.3-12
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• 1988

A natural or an artificial harbor can exhibit frequency(or period) dependent water surface oscillations when excited by incident waves. Such oscillations in harbors can cause significant damage to moored ships and adjacent structures. This can also induce undesirable current in harbors. Many previous investigators have studied various aspects of harbor resonance problem. In the percent paper, both a localizes finite element method(LFEM) which is based on the functional constructed by Chen & Mei(1974) and Bai & Yeung(1974) and an integral equation method which was used by Lee(1969) are applied to harbor resonance problem. The present method(LFEM) shows computationally more efficient than the integral equation method. Our test results shows good agreement compared with other results. This enhanced computational efficiency is due to the fact that the present method gives a banded symmetric coefficients matrix and requires much less computational time in the calculation of the influence coefficients matrix than the integral equation method involved with Green's function. To test the present numerical scheme, two models are treated here. The present method(LFEM) can be extended to a fully three dimensional harbor problem with the similar computational advantage.

• Current Optics and Photonics
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• v.2 no.3
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• pp.226-232
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• 2018

We propose a triangular-multicore hollow optical fiber (TMC-HOF) design for uncoupled mode-division and space-division multiplexing. The TMC-HOF has three triangular cores, and each core has three modes: $LP_{01}$ and two split $LP_{11}$ modes. The asymmetric structure of the triangular core can split the $LP_{11}$ modes. Using the proposed structures, nine independent modes can propagate in a fiber. We use a fully vectorial finite-element method to estimate effective index, chromatic dispersion, differential group delay (DGD), and confinement loss by controlling the parameters of the TMC-HOF structure. We confirm that the proposed TMC-HOF shows flattened chromatic dispersion, low DGD, low confinement loss, low core-to-core crosstalk, and low crosstalk between adjacent modes. The proposed TMC-HOF can provide a common platform for MDM and SDM applications.

• Journal of Embryo Transfer
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• v.29 no.4
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• pp.393-395
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• 2014

A 6-year old, Greyhound bitch was presented with vaginal hemorrhage and dystocia. Physical examination revealed severe vaginal hemorrhage, abdominal pain, pale mucous membranes and the presence of solid structures to abdominal palpation. A hematological test revealed a marked hemorrhagic anemia, and abdominal radiography and ultrasonographic examination showed two dead fetuses in the uterus. Median laparotomy revealed a rupture of the left uterine horn adjacent to the bifurcation, region of weakened uterine wall in the right uterine horn, blood clots and uterine fluids in abdominal cavity without septic peritonitis. The bitch underwent ovariohysterectomy and recovered without complication.

• Steel and Composite Structures
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• v.18 no.2
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• pp.325-344
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• 2015

Experimental tests on cellular beams with sinusoidal openings showed two main failure modes around the openings. They concern the formation of four plastic hinges and the local instability of the sinusoidal part of the opening. In parallel, numerical analysis of the sinusoidal part of the opening revealed the existence of an elastic rotational restraint between the intermediate web-post and the adjacent opening panel. The aim of the present study is to present an approach to quantify this rotational restraint. Through the response surface method, a mathematical model is proposed. It shows a great ability to predict the rotational restraint value as a function of the geometrical parameters of the opening. This model can be used to perform an extensive study with various geometrical configurations of beams with the aim to develop a reliable and realistic analytical model predicting the resistance of the sinusoidal openings.

• Journal of Plant Biology
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• v.27 no.2
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• pp.51-60
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• 1984

Jisimdo is an island where evergreen broadleaved forests are well preserved. Soil environments and forest structures of Jisimdo were investigated, and an actual vegetation map and profile diagrams were drawn out. The natural vegetation of Jisimdo was divided into two stand units, one was evergreen broadleaved forest and the other was Pinus thunbergii forest. 26 species were identified as evergreen broadoeaved trees, and among them, Camellia japonica was the dominont of the tree layer of evergreen broadleaved forest. Profile diagram shows that Camellia japonica, with average height of 7∼8m, formed lower tree layer, and laurels like Cinnamomum japonicum, Machilus thunbergii, and Neolitsea sericea formed upper tree layer. In Pinus thunbergii forest, plants of shrub and herb layers were abundant because of much light penetrated into the forest floor, and these layers were largely composed of evergreen broadleaved trees. This fact shows the possibility of succession from Pinus thunbergii forest into evergreen broadleaved forest. Jisimdo is geographically adjacent to Jangseungpo and Okpo, and this increases the economic value of Jisimdo as a place of public resort. It will be necessary from being destroyed by land development and human interferences.

• Earthquakes and Structures
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• v.16 no.6
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• pp.665-677
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• 2019

This study utilizes large-scale shake table test to investigate the seismic performance of an isolated bridge with lead rubber bearings crossing an active fault. Two transverse restraining systems with and without shear keys are tested by applying spatially varying ground motions. It is shown that the near-fault span exhibits larger bearing displacement than the crossing-fault span. Bridge piers away from the fault rupture are more vulnerable than those adjacent to the fault rupture by attracting more seismic demand. It is also verified that the shear keys are effective in restraining the bearing displacement on the near-fault span, particularly under the large permanent ground displacement.