• 상하수도학회지
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• 제29권1호
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• pp.33-38
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• 2015

In this study, flat-type photocatalytic reaction system is applied to reduce toxic hexavalent chromium (Cr(VI)) to trivalent chromium (Cr(III)) in aqueous solution under UV irradiation. To overcome the limitation of conventional photocatalysis, a novel approach toward photocatalytic system for reduction of hexavalent chromium including nanotubular $TiO_2$ (NTT) on two kinds of titanium substrates (foil and mesh) were established. In addition, modified Ti substrates were prepared by bending treatment to increase reaction efficiency of Cr(VI) in the flat-type photocatalytic reactor. For the fabrication of NTT on Ti substrates, Ti foil and mesh was anodized with mixed electrolytes ($NH_4F-H_2O-C_2H_6O_2$) and then annealed in ambient oxygen. The prepared NTT arrays were uniformly grown on two Ti substrates and surface property measurements were performed through SEM and XRD. Hydraulic retention time(HRT) and substrate type were significantly affected the Cr(VI) reduction. Hence, the photocatalytic Cr(VI) reduction was observed to be highest up to 95% at bended(modified) Ti mesh and lowest HRT. Especially, Ti mesh was more effective as NTT substrate in this research.

• 대한두개안면성형외과학회지
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• 제19권3호
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• pp.175-180
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• 2018

Background: The facial bone has a complex structure compared to other bones, and various types of fractures can occur due to its characteristics. Among them, in comminuted fractures of anterior maxillary wall, multiple depressed and impacted bony segments cannot be reduced easily when performing internal fixation using plates and screws or wires, and inadequate restoration leads to a range of complications. This paper introduces an alternative technique using a resorbable mesh with fibrin glue to restore comminuted fractures of anterior maxillary wall. Methods: Thirteen patients were diagnosed with comminuted fractures of anterior maxillary wall between March 2017 and February 2018 in the authors' hospital. All patients with comminuted fractures of anterior maxillary wall underwent restoration using resorbable mesh with fibrin glue. The patients' demographics, causes of facial trauma, mean operation time, length of hospital stay, follow-up period, and complications were recorded. Results: No major complications and only one hypoesthesia of the skin area was noted. Three months after surgery, the hypoesthesia recovered completely. After surgery (mean, 3.9 months; range, 2-12 months), computed tomography showed that the bone fragments in all patients were fixed successfully in their anatomical places. Conclusion: In comminuted fractures of anterior maxillary wall, the use of a resorbable mesh with fibrin glue can be an advantageous and effective method for a successful restoration without complications.

• 대한두개안면성형외과학회지
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• 제11권2호
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• pp.85-90
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• 2010

Purpose: The goals of a blow-out fracture reconstruction are to restore the osseous continuity, provide support for the orbital contents and prevent functional and anatomic defects. Over the past several years, a range of autogenous and synthetic implants have been used extensively in orbital reconstructions. None of these implants have any absolute indications or contraindications in certain clinical settings. However, in extensive blow-out fractures, it is difficult to restore support of the orbital contents, which can cause more complications, such as enophthalmos. This study examined the clinical outcomes of extensive or comminuted blow-out fractures that were reconstructed by the simultaneous use of a titanium mesh plate and $Medpor^{(R)}$. Methods: Eighty six patients with extensive orbital fractures, who were admitted between March 1999 and February 2007, were reviewed retrospectively. The patients' chart and CT were inspected for review. Twenty three patients were operated on with both a titanium mesh plate (Matrix MIDFACE pre-formed orbital plate, Synthes, USA) and $Medpor^{(R)}$ (Porex, GA, USA). The patients underwent pre-operative CT scans to evaluate the fracture site and measure the area of the fracture. A transconjunctival approach was used, and titanium mesh plates were inserted subperiosteally with screw fixation. $Medpor^{(R)}$ was inserted above the titanium mesh plate. The patients were evaluated post-operatively for enophthalmos, diplopia, sensory disturbances and eyeball movement for a period of at least 6 months. Results: No implant-related complications were encountered during the follow-up period. Enophthalmos occurred in 1 patient, 1 patient had permanent sensory disturbance, and 3 patients complained of ocular pain and fatigue, which recovered without treatment. Although there were no significance differences between groups, the use of 2 implants had fewer complications. Therefore, it can be an alternative method for treating blow out fractures. Conclusion: The use of both a titanium mesh plate and $Medpor^{(R)}$ simultaneously may be a safe and acceptable technique in the reconstruction of extensive blow-out fractures.

• 한국대기환경학회지
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• 제31권2호
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• pp.118-130
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• 2015

Fine dust containing iron compounds is of current interests in metro subway as well as large scale industries including iron manufacturing and smelting works. This work attempts to find a new design of magnetic filter module for iron dust capture. It simulated the vertical rectangular duct with metal mesh which might promote electric fields in the duct space. A lab test using coal fly ash composed of 8.66% Fe with the most form of $Fe_3O_4$ and $Fe_2O_3$ showed capability of magnetic collection. It showed the capture efficiency with 80~93% for $PM_{2.5}$ depending on magnetic intensity. Ferromagnetic wire mesh contributed up to 50% of collection increment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1283-1287
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• 2003

Reverse engineering technology refers to the process that creates a CAD model of an existing part using measuring devices. Recently, non-contact scanning devices have become more accurate and the speed of data acquisition has increased drastically. However, they generate thousands of points per second and various types of point data. Therefore. it becomes a important to handle the huge amount and various types of point data to generate a surface model efficiently. This paper proposes a new triangular mesh generation method using 3D grids. The geometric information of a part can be obtained from point cloud data by estimating normal values of the points. In our research, the non-uniform 3D grids are generated first for feature based data reduction based on the geometric information. Then, triangulation is performed with the reduced point data. The grid structure is efficiently used not only for neighbor point search that can speed up the mesh generation process but also for getting surface connectivity information to result in same topology surface with the point data. Through this integrated approach, it is possible to create surface models from scanned point data efficiently.

• Nuclear Engineering and Technology
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• 제52권3호
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• pp.485-498
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• 2020

A diffusion synthetic acceleration (DSA) technique for the S_N transport equation discretized with the linear discontinuous expansion method with subcell balance (LDEM-SCB) on unstructured tetrahedral meshes is presented. The LDEM-SCB scheme solves the transport equation with the discrete ordinates method by using the subcell balances and linear discontinuous expansion of the flux. Discretized DSA equations are derived by consistently discretizing the continuous diffusion equation with the LDEM-SCB method, however, the discretized diffusion equations are not fully consistent with the discretized transport equations. In addition, a fine mesh rebalance (FMR) method is devised to accelerate the discretized diffusion equation coupled with the preconditioned conjugate gradient (CG) method. The DSA method is applied to various test problems to show its effectiveness in speeding up the iterative convergence of the transport equation. The results show that the DSA method gives small spectral radii for the tetrahedral meshes having various minimum aspect ratios even in highly scattering dominant mediums for the homogeneous test problems. The numerical tests for the homogeneous and heterogeneous problems show that DSA with FMR (with preconditioned CG) gives significantly higher speedups and robustness than the one with the Gauss-Seidel-like iteration.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.55-58
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• 2002

Parallel finite element code has been recently developed for the analysis of the incompressible Wavier-Stokes equations using domain decomposition method. Metis and MPI libraries are used for the domain partitioning of an unstructured mesh and the data communication between sub-domains, respectively. For unsteady computation of the incompressible Navier-Stokes equations, 4-step splitting method is combined with P1P1 finite element formulation. Smagorinsky and dynamic model are implemented for the simulation of turbulent flows. For the validation performance-estimation of the developed parallel code, three-dimensional Laplace equation has been solved. It has been found that the speed-up of 40 has been obtained from the present parallel code fir the bench mark problem. Lastly, the turbulent flows around the MIRA model and Tiburon model have been solved using 32 processors on IBM SMP cluster and unstructured mesh. The computed drag coefficient agrees better with the existing experiment as the mesh resolution of the region increases, where the variation of pressure is severe.

• 한국콘텐츠학회논문지
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• 제7권6호
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• pp.52-59
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• 2007

이 논문은 삼차원 메쉬의 의미있는 조각의 기하적 속성을 나타내기 위하여 정의한 병합우선순위메트릭에 기반한 사용자 의도 메쉬분할의 그리디 방법을 제시한다. 우선순위메트릭은 가우시안사상의 분포, 경계경로의 오목성, 경계경로의 길이, 면의 개수, 분할해상도의 5 가지 기하적 매개변수로 구성된 가중치 함수이다. 이러한 방식은 구도의 변경 없이 다른 기하적 매개변수를 정의하고 추가함으로써 확장될 수 있다. 실험 결과, 분할된 조각의 모양은 기하적 매개변수의 가중치를 부여함으로써 사용자 의도대로 조절될 수 있음을 보여준다.

• 한국임상수의학회지
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• 제39권6호
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• pp.378-383
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• 2022

A 3-year-old, 24-kg intact female Border Collie was referred for a toe-touch weight-bearing stance, intermittent weight-bearing lameness, and moderate pain reaction of the right forelimb on physical examination and right humerus olecranon avulsion fracture on diagnostic imaging examination. Surgical repair was performed using tension band wiring to re-attach the triceps tendon and distal olecranon. Migration of the distal olecranon fragment was observed due to comminuted fracture of the fragment 5-days after surgery, and revision surgery was performed. The tension-relieving sutures were passed through the pre-drilled hole in the olecranon, and the polyester mesh was augmented to the suture region, covering the triceps tendon and olecranon drilling hole using the Krackow suture pattern. The elbow joint was immobilized using a type IA transarticular external fixator, which was removed 8 weeks after surgery. Fourteen weeks after surgery, no lameness was observed on gait evaluation. At follow-up after 7 months, the distal olecranon fragment had stabilized, and no lameness was observed.

• 지적과 국토정보
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• 제44권1호
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• pp.139-150
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• 2014

최근 강력 범죄의 증가는 중요한 사회적인 이슈가 되고 있다. 현대 사회에서의 범죄 예방은 단순한 치안 유지만이 아니라, 국민 복지의 문제로 살펴야하는 중요한 요소이다. 본 연구에서는 이러한 범죄를 예방하기 위하여 범죄공간정보의 특성과 분석 방법에 대하여 연구를 진행하였다. 이러한 연구결과를 이용하여 공간정보오픈플랫폼인 브이월드(Vworld)를 사용한 시범 시스템을 구현하였으며, 시범지역의 범죄공간정보 DB 링크시스템 및 분석 데이터를 주제도 이미지 지도 위에 Mesh-Up으로 표출한 우범지역관리 모니터링 시스템을 개발하고 순찰차 CCTV 최적 배치 등의 가상 시뮬레이션 모형을 제시하였다.