• Journal of Chest Surgery
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• v.28 no.11
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• pp.1045-1048
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• 1995

Pulmonary atresia with VSD is uncommon congenital anomaly with high mortality in neonatal period.Recently we experienced surgical correction of pulmonary atresia with VSD. The case was 2 month old male patient diagnosed as pulmonary atresia with VSD and PDA. Atretic pulmonary artery segment from Rt ventricular infundibulum to pulmonary artery was lcm in length. The pulmonary trunk tapered toward Right ventricular infundibulum and resulted in blind pouch with diameter of lmm. The left pulmonary artery was stenosed at just proximal and distal part to which PDA was connected. Total correction was undertaken which consisted of PDA ligation, dacron patch closure of VSD, establishment of continuity between right ventricle and pulmonary artery with autogenous pericardium. Postoperative systolic fight ventricular pressure and left ventricular pressure ratio was 0.7. In patient with pulmonary atresia with VSD it is advisable to perform a corrective operation, whenever the size and anatomy of pulmonary artery are acceptable for it.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.56-61
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• 1986

Rotor dynamic response of pumps is greatly influenced by the nature of the hydraulic forces arising from wearing seal, balance drum and impeller, etc.. Therefore, rotor dynamic analysis should be conducted during the design stage in order to aleviate some of the vibrational problems which might occur during the operational life of pumps. Previsousely, the authors have proposed the method to obtain the dynamic seal coefficients of the annular plain seal, convergent and divergent tapered seals, parallel grooved seal, spiral grooved seal and annular stepped seal. On the basis of these results, this paper presents the investigated effect of seals on the stability behavior of a centrifugal pump. The results show the effects of seal geometry, pressure difference, clearance, length/diameter ratio, on stability behavior.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.3
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• pp.21-24
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• 1981

A simple optial fiber Y-branch is fabricated using micro - torch and fusion splicer. Tapered end of two fibers - in -contact is spliced with another fiber. Total insertion loss is 26dB and optical power branchi ng ratio is 0.98. Using fiber Y-branch, an UTDR with simple optical system is realized The resolution of the OTDR is $\pm$ 5m in length and t 0.5 dB/km in loss coefficient.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.1
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• pp.87-93
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• 2001

이 논문은 사하중에 의한 정적 처짐을 갖는 변단면 보의 자유진동에 관한 연구이다. 사하중이 작용하는 변단면 보의 자유진동을 지배하는 상미분방정식을 유도하고 이를 수치해석하여 최 저차 3개 모드의 고유진동수 및 진동형을 산출하였다. 수치해석 예제에서는 선형 변단면과 등분포 사하중을 채택하였다. 지점조건으로는 회전-회전, 회전-고정, 고정-고정 보를 채택하였다. 수치해석의 결과로 하중강도, 세장비 및 단면비가 고유진동수에 미치는 영향을 분석하였다. 사하중의 영향을 고려한 경우와 고려하지 않은 경우의 진동형을 서로 비교하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.943-948
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• 1996

In this paper. we will discuss in making large size cylindrical shells with multithickness wall sections such as straight, stepped, tapered sides. These shells are constructed of type 6061 O temper aluminum starting with a blanking size of 877 mm plate. Its diameter to length ratio of 1 to 2.78 and a 36.7％ wall reduction is achieved by our continuous deep drawing process. This process required no in-process annealing. But after cold working, these shells is performed heat treatment to T6 condition. These shells are used for the making of seamless LPG pressure vessels after the spinning process. This process is composed of deep drawing, reverse redrawing, drawing-ironing and several ironing processes. In the verification of forming process design, we used DEFORM code.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.1
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• pp.25-40
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• 2015

Understanding the effects of the parameters affecting the interaction of tandem hydrofoil system is a crucial subject in order to fully comprehend the aero/hydrodynamics of any vehicle moving inside a fluid. This study covers a parametric study on tandem hydrofoil interaction in both potential and viscous fluids using iterative Boundary Element Method (BEM) and RANSE. BEM allows a quick estimation of the flow around bodies and may be used for practical purposes to assess the interaction inside the fluid. The produced results are verified by conformal mapping and Finite Volume Method (FVM). RANSE is used for viscous flow conditions to assess the effects of viscosity compared to the inviscid solutions proposed by BEM. Six different parameters are investigated and they are the effects of distance, thickness, angle of attack, chord length, aspect ratio and tapered wings. A generalized 2-D code is developed implementing the iterative procedure and is adapted to generate results. Effects of free surface and cavitation are ignored. It is believed that the present work will provide insight into the parametric interference between hydrofoils inside the fluid.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.731-736
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• 2016

Three-dimensional (3D) high-aspect-ratio (HAR) microstructures for biomedical applications (e.g., microneedle, microadhesive, etc.) are microfabricated using the hybrid ultraviolet (UV) lithography in which inclined, rotational, and reverse-side UV exposure processes are combined together. The inclined and rotational UV exposure processes are intended to fabricate tapered axisymmetric HAR microstructures; the reverse-side UV exposure process is designed to sharpen the end tip of the microstructures by suppressing the UV reflection on a bottom substrate which is inevitable in conventional UV lithography. Hybrid UV lithography involves fabricating 3D HAR microstructures with an epoxy-based negative photoresist, SU-8, using our customized UV exposure system. The effects of hybrid UV lithography parameters on the geometry of the 3D HAR microstructures (aspect ratio, radius of curvature of the end tip, etc.) are measured. The dependence of the end-tip shape on SU-8 soft-baking condition is also discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.43-50
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• 1992

The purpose of this study is to ascertain the robustness of p-version model with hierarchic intergrals of Legendre shape functions in various applications including plane stress/strain, axisymmetric and shell problems. The most important symptoms of accuracy failure in modern finite elements are spurious mechanisms and a phenomenon known as locking which are exhibited for incompressible materials and irregular shapes which contain aspect ratios(R/t, a/b), tapered ratio(d/b), and skewness. The condition numbers and energy norms are used to estimate numerical errors, convergence characteristics and algorithmic efficiencies for verifying the aforementioned symptoms of accuracy failure. Numerical results from p-version models are compared with those from NASTRAN, SAP90, and Cheung's hybrid elements.

• Journal of Veterinary Clinics
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• v.32 no.6
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• pp.523-526
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• 2015

A 9-year-old, castrated male Malamute dog was presented with chronic cough. On thoracic computed tomography, non-tapered and dilated peripheral bronchi were detected. Bronchoarterial ratio was about 2.2. The dilated bronchi appeared as a cluster of grapes especially in left cranial, left caudal and right middle lung lobe. Based on the computed tomographic findings, the diagnosis was made as the saccular type of bronchiectasis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.5
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• pp.254-259
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• 2019

Objectives: Crown-root fracture and cervical caries in maxillary premolars constitute a challenge in cases of subgingival placement of restoration margins. Surgical extrusion has been practiced successfully in permanent anterior teeth. The aim of the present retrospective study was to assess the clinical outcome of surgical extrusion after orthodontic extrusion in maxillary premolars. Materials and Methods: Twenty-one single, tapered root maxillary premolars with subgingival crown-root fracture or caries were included. Presurgical orthodontic extrusion was performed on all teeth to prevent root resorption. Extent of extrusion and rotation was determined based on crown/root ratio. The postoperative splinting period was 7 to 14 days. Clinical and radiographic examination was performed at an interval of 1, 2, and 3 months. Results: After the mean follow-up of $41.9{\pm}15.2months$, failure was observed as increased mobility in 3 of 21 cases. No significant difference was observed in the outcome of surgical extrusion based on tooth type, age, sex, $180^{\circ}$ rotation, or time for extraction. Furthermore, marginal bone loss was not observed. Conclusion: Surgical extrusion of maxillary premolars can be a possible therapeutic option in cases of subgingival crown-root fracture.