• Structural Engineering and Mechanics
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• 제54권3호
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• pp.579-595
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• 2015

A general geometrically non-linear model for lateral-torsional buckling of thick and thin-walled FGM box beams is presented. In this model primary and secondary torsional warping and shear effects are taken into account. The coupled equilibrium equations obtained from Galerkin's method are derived and the corresponding tangent matrix is used to compute the critical moments. General expression is derived for the lateral-torsional buckling load of unshearable FGM beams. The results are validated by comparison with a 3D finite element simulation using the code ABAQUS. The influences of the geometrical characteristics and the shear effects on the buckling loads are demonstrated through several case studies.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.71-78
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• 1997

The high precision analysis by the p-version of the finite element method are fairly well established as highly efficient method for linear elastic problems, especially in the presence of stress singularity. It has been noted that the merits of p-version are accuracy, modeling simplicity, robustness, and savings in user's and CPU time. However, little has been done to exploit their benefits in elasto-plastic analysis. In this paper, the p-version finite element model is proposed for the materially nonlinear analysis that is based on the incremental theory of plasticity, the associated flow rule, and von-Mises yield criteria. To obtain the solution of nonlinear equation, the Newton-Raphson method and initial stiffness method, etc are used. Several numerical examples are tested with the help of the square plates with cutout, the thick-walled cylinder under internal pressure, and the center cracked plate under tensile loading. Those results are compared with the there cal solutions and the numerical solutions of ADINA software.

• 아시안잔디학회지
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• 제1권1호
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• pp.42-48
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• 1987

This study was carried out to elucidate the physiological and ecological mechamism of the branch pattern and electronmicroscopic structure of photosynthetic organs in Zoysia japonica Steud. The angles between the internodes of rhizome and the branches of Z.iaponica were changed from 0 to 52 degrees. The rhizomes tended to branch from the 3th node to the 10th node. When the terminal bud was damaged by various environmental factors, the initial branching formation was appeared immediately to the 4th node. The internode growth of the rhizome started from the beginning of April and continued to the end of Octobor. It became evident that there is a division labor between two different kinds of photosynthetic cells of mesophyll and bundle sheath tissues in Z.japonica The thick-walled bundle sheath cells surrounds the leaf vascular bundles as the Kranz type and separates them from the mesophyll cells.

• 대한세포병리학회지
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• 제19권2호
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• pp.188-193
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• 2008

Angiomyolipoma of the liver is a rare benign tumor that's composed of variable mixtures of adipose tissue, smooth muscle and thick-walled blood vessels. We report here on the imprint cytologic features of a hepatic angiomyolipoma in a 47-year-old man. The smears showed spindle and epithelioid tumor cells in clusters, trabeculae and single cells. The spindle cells had elongated, cigar-shaped nuclei with finely granular chromatin and fibrillary cytoplasm. The epithelioid cells had round nuclei with a moderate amount of cytoplasm. Any adipose tissue was not found. Immunohistochemically, both the spindle and epithelioid cells revealed cytoplasmic positivity for smooth muscle actin and HMB-45.

• 설비공학논문집
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• 제18권5호
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• pp.451-457
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• 2006

Conjugate heat transfer (CHT) is the simultaneous, coupled heat transfer within a fluid and an adjoining solid, and the interface treatment plays an important role in its analysis, particularly when using unstructured grid system. In the present paper a new solid-fluid interface treatment in CHT analysis is presented and applied to two typical CHT problems, i.e. natural convections in both concentric thick-walled cylinders and cavity with a centered solid body. The present interface treatment for unstructured mesh clearly demonstrates the same accuracy and robustness as that for typical structured mesh.

• Journal of Chest Surgery
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• 제54권6호
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• pp.532-534
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• 2021

This study examined a rarely seen benign heart tumor that was found incidentally on a chest X-ray. Radiological images were taken of a 42-year-old patient with no symptoms of a heart condition, showing a thick-walled left lung cavity that appeared after prior inflammation and concomitant enlargement of the cardiac shadow. A large subepicardial lipoma in combination with a chronic abscess on the left lung was revealed on chest computed tomography. The treatment consisted of simultaneous surgical removal of both the lung and heart lesions using video-assisted thoracoscopic surgery.

• 대한영상의학회지
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• 제83권3호
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• pp.693-698
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• 2022

자궁 경부 혈관근종은 평활근 세포와 두꺼운 벽의 혈관으로 구성되어 있는 극히 드문 양성 종양이다. 현재 자궁 경부 혈관근종에 대한 증례 보고는 거의 없는 것으로 알려져 있다. 저자들은 38세 여성의 증례를 통하여 자궁 경부 혈관근종의 초음파, 조영증강 전산화단층촬영, 자기공명영상을 포함한 영상학적, 그리고 병리학적 소견에 대하여 보고하고자 한다.

• Structural Engineering and Mechanics
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• 제77권1호
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• pp.137-149
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• 2021

In engineering design, the axial equivalent elastic modulus of laminated FRP pipe was mostly calculated by the average elastic modulus method or the classical laminated plate theory method, which are based on relatively simplified assumptions, and may be not accurate enough sometimes. A new analytical calculation method for the axial equivalent elastic modulus of laminated FRP pipe was established based on three-dimensional stress state. By comparing the results calculated by this method with those by the above two traditional analytical methods and the finite element method, it is found that this method for the axial equivalent elastic modulus fits well not only for thin-walled pipes with orthotropic layers, but also for thick-walled pipes with arbitrary layers. Besides, the influence of the layer stacking on the axial equivalent elastic modulus was studied with this method. It is found that a proper content of circumferential layer is beneficial for improving the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers, and then can reduce its material quantity under the premise that its axial stiffness remains unchanged. Finally, the meso-mechanical mechanism of this effect was analyzed. The improving effect of circumferential layer on the axial equivalent elastic modulus of the laminated FRP pipe with oblique layers is mainly because that, the circumferential fibers can restrain the rigid body rotations of the oblique fibers, which tend to cause the significant deformations of the pipe wall units and the relatively low axial equivalent elastic modulus of the pipe.

• 식물병연구
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• 제10권3호
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• pp.175-182
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• 2004

2003∼2004년 향나무에서 Gymnosporangium ariurirem과 G.yamadae 두종의 겨울포자를 채집하여 관찰하였다. 향나무에서 채집한 G.asiaticum의 겨울포자는 막이 두꺼운 (평균 2.5 $\mu\textrm{m}$)후막겨울포자와 막이 얇은(평균 1.2 $\mu\textrm{m}$)박 막겨울포자가 관찰되었으며, G.asiaticum의 겨울포자퇴는 무딘원뿔모양으로 향나무의 잎, 가지에서 발생되었다. G.yamadae 의 겨울포자 또한 막이 두꺼운(평균 2.5 $\mu\textrm{m}$) 후막겨울포자와 막이 얇은(평균 1.2 $\mu\textrm{m}$) 박막겨울포자가 관찰되었으며, G.yamodae의 겨울포자퇴는 향나무의 잎에 주로 발생하였으며 혹모양 또는 꽃모양으로 형성되었다. G.yamodae는 G.asiaticum보다 더 둥글면서 끝은 약간 뽀족하게 돌출된 모양이었다. 또한 한 그루의 향나무에서 두 종류의 겨울포자퇴가 동시에 형성되는 것도 관찰하였다. 그러나 G.asiaticum이 G.yamodae보다 우점종이었다(류, 2004). 모과나무의 붉은별무의병은 강우량에 따라 매년 발병 양상이 달라지는데 담자포자의 형성시기인 4월 하순의 강우량이 많으면 병의 발생도 많았다. 또한 G.asiaticum의 병원성을 검정한 결과 모과나무와 배나무에서 병이 발생하였지만 아그배나무에서는 병이 발생하지 않았다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.264-264
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• 2010

Single-walled carbon nanotubes (SWCNTs) were grown on a Si wafer by using thermal chemical vapor deposition (t-CVD). We investigated the effect of the catalyst deposition rate on the types of CNTs grown on the substrate. In general, smaller islands of catalyst occur by agglomeration of a catalyst layer upon annealing as the catalyst layer becomes thinner, which results in the growth of CNTs with smaller diameters. For the same thickness of catalyst, a slower deposition rate will cause a more uniformly thin catalyst layer, which will be agglomerated during annealing, producing smaller catalyst islands. Thus, we can expect that the smaller-diameter CNTs will grow on the catalyst deposited with a lower rate even for the same thickness of catalyst. The 0.5-nm-thick Fe served as a catalyst, underneath which Al was coated as a catalyst support as well as a diffusion barrier on the Si substrate. The catalyst layers were. coated by using thermal evaporation. The deposition rates of the Al and Fe layers varied to be 90, 180 sec/nm and 70, 140 sec/nm, respectively. We prepared the four different combinations of the deposition rates of the AI and Fe layers. CNTs were synthesized for 10 min by flowing 60 sccm of Ar and 60 sccm of $H_2$ as a carrier gas and 20 sccm of $C_2H_2$ as a feedstock at 95 torr and $810^{\circ}C$. The substrates were subject to annealing for 20 sec for every case to form small catalyst islands prior to CNT growth. As-grown CNTs were characterized by using field emission scanning electron microscopy, high resolution transmission electron microscopy, Raman spectroscopy, UV-Vis NIR spectroscopy, and atomic force microscopy. The fast deposition of both the Al and Fe layers gave rise to the growth of thin multiwalled CNTs with the height of ${\sim}680\;{\mu}m$ for 10 min while the slow deposition caused the growth of ${\sim}800\;{\mu}m$ high SWCNTs. Several radial breathing mode (RBM) peaks in the Raman spectra were observed at the Raman shifts of $113.3{\sim}281.3\;cm^{-1}$, implying the presence of SWCNTs (or double-walled CNTs) with the tube diameters 2.07~0.83 nm. The Raman spectra of the as-grown SWCNTs showed very low G/D peak intensity ratios, indicating their low defect concentrations.