• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.137-140
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• 2002

In this paper, a new algorithm for two-dimensional (2-D) finite-difference time-domain (FDTD) method is presented. By this new method, the maximum time step size can be increased over the Courant-Friedrich-Levy (CFL) condition restraint. This new algorithm is adapted from an Alternating-Direction Implicit FDTD (ADI-FDTD) method. However, unlike the ADI-FDTD algorithm. the alternation is performed with respect to the blocks of fields rather than with respect to each respective coordinate direction. Moreover. this method can be efficiently simulated with parallel computation. and it is more efficient than the conventional FDTD method in terms of CPU time. Numerical formulations are shown and simulation results are presented to demonstrate the effectiveness and efficiency of our proposed method.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2000년도 추계 학술대회논문집
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• pp.129-134
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• 2000

An efficient numerical method to solve the unsteady incompressible Navier-Stokes equations is developed. A fully implicit time advancement is employed to avoid the CFL(Courant-Friedrichs-Lewy) restriction, where the Crank-Nicholson discretization is used for both the diffusion and convection terms. Based on a block LU decomposition, velocity-pressure decoupling is achieved in conjunction with the approximate factorization. Main emphasis is placed on the additional decoupling of the intermediate velocity components with only n th time step velocity The temporal second-order accuracy is Preserved with the approximate factorization without any modification of boundary conditions. Since the decoupled momentum equations are solved without iteration, the computational time is reduced significantly. The present decoupling method is validated by solving the turbulent minimal channel flow unit.

• 한국전산유체공학회지
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• 제12권2호
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• pp.14-20
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• 2007

We present an improved immersed boundary method for computing incompressible viscous flow around an arbitrarily moving body on a fixed computational grid. The main idea is to incorporate feedback forcing scheme of virtual boundary method with Peskin's regularized delta function approach in order to use large CFL number and transfer quantities between Eulerian and Lagrangian domain effectively. From the analysis of stability limits and effects of feedback forcing gains, optimum regions of the feedback forcing are suggested.

• 대한방사선협회지
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• 제27권2호
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• pp.115-123
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• 2001

The two ligaments, the anterior talofibular ligament(ATFL) and the calcaneofibular ligament(CFL), arise from the anteroinferior aspect of the lateral malleolus, and therefore avulsion fragments are superimposed on the lateral malleolus on the srandard rad

• Neonatal Medicine
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• 제28권2호
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• pp.89-93
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• 2021

Nemaline myopathy is a genetically heterogeneous neuromuscular disorder and one of the most common congenital myopathies. The clinical manifestations usually vary depending on the age of onset. Neonatal nemaline myopathy has the worst prognosis, primarily due to respiratory failure. Several genes associated with nemaline myopathy have been identified, including NEB, ACTA1, TPM3, TPM2, TNNT1, CFL2, KBTBD13, KLHL40, KLHL41, LMOD3, and KBTBD13. Here, we report a neonatal Korean female patient with nemaline myopathy carrying compound heterozygous mutations in the gene KLHL40 as revealed using next generation sequencing (NGS). The patient presented with postnatal cyanosis, respiratory failure, dysphagia, and hypotonia just after birth. To identify the genetic cause underlying the neonatal myopathy, NGS-based gene panel sequencing was performed. Compound heterozygous pathogenic variants were detected in KLHL40: c.[1405G>T];[1582G>A] (p. [Gly469cys];[Glu528Lys]). NGS allows quick and accurate diagnosis at a lower cost compared to traditional serial single gene sequencing, which is greatly advantageous in genetically heterogeneous disorders such as myopathies. Rapid diagnosis will facilitate efficient and timely genetic counseling, prediction of disease prognosis, and establishment of treatments.

• The Plant Pathology Journal
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• 제33권4호
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• pp.351-361
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• 2017

Bacterial canker is the largest limiting factor in the cultivation and production of kiwifruit worldwide. Typical symptoms comprise necrotic spots on leaves, canker and dieback on canes and trunks, twig wilting, and blossom necrosis. Pseudomonas syringae pv. actinidiae (Psa), which is the causal agent of kiwifruit bacterial canker, is divided into four biovars based on multilocus sequence analysis of different genes, additional PCR testing of pathogenic genes (argKtox cluster, cfl, and various effector genes), and biochemical and physiological characterization. Bacterial canker caused by Psa biovar 2 designated Psa2 was detected for the first time on the green-fleshed kiwifruit cultivar Hayward in 1988 and the yellow-fleshed kiwifruit cultivar Hort16A in 2006 in Korea. Psa biovar 3 designated Psa3, responsible for the current global pandemics of kiwifruit bacterial canker, began to appear in Korea in 2011 and caused tremendous economic losses by destroying many vines or orchards of yellow-fleshed kiwifruit cultivars in one or several growing seasons. Bacterial canker epidemics caused by both Psa2 and Psa3 are prevalent in Korea in recent years. In this review, we summarize the symptomatology, etiology, disease cycle, diagnosis, and epidemiology of kiwifruit bacterial canker in Korea.

• 천문학회보
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• 제40권1호
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• pp.65.2-65.2
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• 2015

We developed a three-dimensional magnetohydrodynamic (MHD) code to reproduce the structure of a solar wind, the properties of a coronal mass ejection (CME) and the interaction between them. This MHD code is based on the finite volume method incorporating total variation diminishing (TVD) scheme with an unstructured grid system. In particular, this grid system can avoid the singularity at the north and south poles and relax tight CFL conditions around the poles, both of which would arise in a spherical coordinate system (Tanaka 1994). In this model, we first apply an MHD tomographic method (Hayashi et al. 2003) to interplanetary scintillation (IPS) observational data and derive a solar wind from the physical values obtained at 50 solar radii away from the Sun. By comparing the properties of this solar wind to observational data obtained near the Earth orbit, we confirmed that our model captures the velocity, temperature and density profiles of a solar wind near the Earth orbit. We then insert a spheromak-type CME (Kataoka et al. 2009) into the solar wind to reproduce an actual CME event. This has been done by introducing a time-dependent boundary condition to the inner boundary of our simulation domain. On the basis of a comparison between a simulated CME and observations near the Earth, we discuss the physics involved in an ICME interacting with a solar wind.

• 한국전기전자재료학회논문지
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• 제26권10호
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• pp.778-784
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• 2013

In order to develop a LED luminaire for naval-submarines which can replace a conventional one with two-compact fluorescent lamp (CFL) of 18 W, we analyzed the electrical and optical performance of the conventional luminaire. A LED luminaire was fabricated as compact as possible based on the analyzed data. The weight of the prototype LED luminaire is 1.8 kg, reducing up to 58% of the conventional one. The use of LED package for the submarine luminaire could reduce the power consumption from 38 W to 14.5 W with the same optical performance. The reason is that the optical efficacy of the LED luminaire improved by 2.47 times as 61.9 lm/W, compared to 25.1 lm/W for the conventional one.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.91.1-91.1
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• 2011

고체산화물 연료전지(Solid Oxide Fuel Cell이하 SOFC)는 연료가 갖는 화학에너지를 연소과정 없이, 공기와 H2, CO, CH4와 같은 환원성 가스를 공급받아 $600{\sim}1000^{\circ}C$에서 전기화학적 반응을 통하여 직접 전기를 얻는 방식이다. SOFC는 $700^{\circ}C$ 이상의 고온에서 고체산화물이 연료와 공기가 반응하여 전기와 열을 동시에 생산하기 때문에 carnot cycle의 제한을 받지 않아 발전효율이 40% 이상으로 고효율이고, NOx 및 SOx를 배출하지 않아 무공해이며, moving parts가 없어 소음이 나지 않고, 건설과 증설이 지역이나 기후 조건에 제약 없이 용이하고, 다양한 용량이 가능하며, 고가의 백금 촉매를 사용하지 않으며, 수소, 석탄가스, 천연가스 등의 연료를 사용할 수 있는 장점이 있음, 또한 다향한 형태로 제작할 수 있으며 전해질이 고체에서 전해질 손실 및 보충에 문제가 없고 타 연료전지에 비해 개질기가 필요 없어 발전시스템이 간단하고 경량화가 가능하다. 전사법은 paste를 제작하여 전사용지에 Screen printing하여 건조 후 coating하는 방법으로 기존의 여러 coating 방법보다 제작이 용이하고 소재의 크기, 두께조절이 간편하며, 구성층의 표면조도나 굴곡에 대응이 용이한 방법이다. 본 실험에서는 paste 제조, 전사법을 이용하여 Anode, AFL, Electrolyte, CFL, Cathode전사지를 제작하고 이를 세라믹 평관형 지지체에 변수로 두께 조건별 Coating 한 후 $1400^{\circ}C$ 소결을 진행하여 SEM 분석으로 미세구조 관찰, 출력특성 및 Impedance을 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.586-591
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• 2001

This research investigated the feasibility of the accelerated carbonation of cement waste forms with carbon dioxide in a supercritical state. Hydraulic cement has been used as a main solidification matrix for the immobilization of radioactive and/or hazardous wastes. As a result of the hydration reaction for major compounds of portland cement, portlandite (Ca(OH)$_2$) is present in the hydrated cement waste form. The chemical durability of a cement form is expected to increase by converting portlandite to the less soluble calcite (CaCO$_3$). For a faster reaction of portlandite with carbon dioxide, SCCD (supercritical carbon dioxide) rather than gaseous $CO_2$, in ambient pressure is used. The cement forms fabricated with an addition of slated lime or Na-bentonite were cured under ambient conditions for 28days and then treated with SCCD in an autoclave maintained at 34$^{\circ}C$ and 80atm. After SCCD treatment, the physicochemical properties of cement matrices were analyzed to evaluate the effectiveness of accelerated carbonation reaction. Conversion of parts of portlandite to calcite by the carbonation reaction with SCCD was verified by XRD (X-ray diffraction) analysis and the composition of portlandite and calcite was estimated using thermogravimetric (TG) data. After SCCD treatment, tile cement density slightly increased by about 1.5% regardless of the SCCD treatment time. The leaching behavior of cement, tested in accordance with an ISO leach test method at 7$0^{\circ}C$ for over 300 days, showed a proportional relationship to the square root of the leaching time, so the major leaching mechanism of cement matrix was diffusion controlled. The cumulative fraction leached (CFL) of calcium decreased by more than 50% after SCCD treatment. It might be concluded that the enhancement of the characteristics of a cement matrix by an accelerated carbonation reaction with SCCD is possible to some extent.