• Journal of applied mathematics & informatics
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• v.22 no.1_2
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• pp.169-180
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• 2006

We study convergence of multisplitting method associated with a block diagonal conformable multisplitting for solving a linear system whose coefficient matrix is a symmetric positive definite matrix which is not an H-matrix. Next, we study the validity of m-step multisplitting polynomial preconditioners which will be used in the preconditioned conjugate gradient method.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.11a
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• pp.73-75
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• 2007

이 논문은 얼굴인식에 있어서 중요한 얼굴 영역과 머리 영역을 차영상을 이용하여 분리하는 방법을 제안한다. 먼저 입력영상에 대한 CMYK 영상 중 K 영상을 가지고 머리 영역을 분리한 후에 YIQ 영상의 Y영상과 머리 영상과의 차영상을 이용하여 얼굴영역을 분리한다. 분리한 머리영역과 얼굴영역에 대하여 라벨링을 하여 각 영역을 얻는다. 제안한 방법은 머리와 얼굴 영역을 뚜렷하게 분리하여 특징 점 추출 시 매우 유용할 것이다.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.69-74
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• 2006

본 연구는 페라이트의 Fe 양이온 일부를 Ni, Mn, Co등으로 치환하여 M-ferrite를 제조하여 열화학적 2단계 물 분해 반응의 특성을 비교 평가하였고, XRD, SEM, GC등의 분석으로 각 금속산화물의 특성을 확인하였다. M-ferrites 는 고상법으로 제조하였다. 각각의 M-ferrite에 대한 열적환원은 1573K 에서 진행하였고 물 분해 반응은 1273K 에서 실시하였다. 이 반응에서 생성된 가스는 전량 포집하여 GC를 통해 분석하였다. 반응 전후의 시료에 대하여 SEM, XRD를 분석하여 GC결과와 함께 금속산화물의 산화환원반응 특성을 고찰하였다. 그 결과로서 물 분해 반응 후 M-ferrite (M=Co, Ni, Mn)의 생성을 XRD를 통하여 확인할 수 있었고, 물 분해 반응과의 비교결과 격자상수의 증대가 M-ferrite내의 산소의 환원에 영향을 미치는 것을 알 수 있었다. SEM결과에서는 4cycle의 물 분해 반응 후 Mn-ferrite의 심한 sintering 현상을 확인 할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.43-46
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• 2006

본 연구는 페라이트의 Fe 양이온 일부를 Ni, Mn, Co등으로 치환하여 M-ferrites를 제조하여 열화학적 2단계 물 분해 반응의 특성을 비교 평가하였고, XRD, SEM, GC등의 분석으로 각 금속산화물의 특성을 확인하였다. M-ferrites는 고상법으로 제조하였다. 각각의 M-ferrites에 대한 열적환원은 1573K에서 진행하였고 물 분해 반응은 1273K에서 실시하였다. 이 반응에서 생성된 가스는 전량 포집하여 GC를 통해 분석하였다. 반응 전후의 시료에 대하여 SEM, XRD를 분석하여 GC결과와 함께 금속산화물의 산화환원반응 특성을 고찰하였다. 그 결과로서 물 분해 반응 후 M-ferrite (M=Co, Ni, Mn)의 생성을 XRD를 통하여 확인할 수 있었고, 물 분해 반응과의 비교결과 격자상수의 증대가 M-ferrite내의 산소의 환원에 영향을 미치는 것을 알 수 있었다. SEM결과에서는 4cycle의 물 분해 반응 후 Mn-ferrite의 심한 sintering 현상을 확인 할 수 있었다.

• Journal of Yeungnam Medical Science
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• v.6 no.2
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• pp.183-194
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• 1989

This is a report of 2-cases of mandibular prognathism corrected by Intraoral oblique splitting osteotomy of mandibular ramus. The Intraoral oblique splitting osteotomy is a modification of sagittal split osteotomy of ramus and it is documented by Yoshida, on 1985. By this method. authors obtained the following results. 1. The patients' esthetic, psychological and functional problems were dissolved by setback of mandibular prognathism. 2. The postoperative infection, splitted bone segments fracture, paresthesia of the face and T.M.J. dysfunction were not appeared. 3. Postoperative intermaxillary fixation was maintained for 8 weeks. The patients could open their mouths in normal range after a week of intermaxillary fixation removal. 4. The soft tissue changes of lower lip and chin were about 1:1 to the hard tissue changes. 5. During intermaxillary fixation period and postoperative orthodontic treatment, slight relapse was observed. Now, the patients are under postoperative orthodontic treatment.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.186-191
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• 1999

An Euler solver is developed to predict accurate aerodynamic data such as lift coefficient, drag coefficient, and moment coefficient. The conservation law form of the compressible Euler equations are used in the generalized curvilinear coordinates system. The Euler solver uses a finite volume method and the second order Roe's flux difference splitting scheme with min-mod flux limiter to calculate the fluxes accurately. An implicit scheme which includes the boundary conditions is implemented to accelerate the convergence rate. The multi-block grid is integrated into the flow solver for complex geometry. The flowfields are analyzed around NACA 0012 airfoil in the cases of $M_{\infty}=0.75,\;\alpha=2.0\;and\;M_{\infty}=0.80,\;\alpha=1.25$. The numerical results are compared with other numerical results from the literature. The final goal of this research is to prepare a robust and an efficient Navier-Stokes solver eventually.

• The Korean Journal of Mycology
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• v.50 no.2
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• pp.125-130
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• 2022

The powdery mildew found on Magnolia kobus was recorded as Microsphaera alni for the first time in Korea in 1975. After splitting M. alni into several distinct species, this mildew was regarded as Microsphaera magnifica, now Erysiphe magnifica. Since E. magnifica is known to be a North American species, the powdery mildew found on M. kobus in Korea was studied to clarify its identity. Based on morphological characteristics and sequencing results of the internal transcribed spacer and large subunit rDNA gene, the powdery mildew found on M. kobus in Korea was identified as Erysiphe magnoliicola.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.184-185
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• 2022

This study researched the effect of graphene nanoribbons (0.05 wt%) on cement-based materials' mechanical and electrical properties. The results were compared with the ordinary Portland cement (OPC) paste and OPC paste with the same content of carbon nanotubes. The experiment results showed that after curing for 28 days, the compressive and splitting tensile strength of the sample with graphene nanoribbons were increased by 17.8% and 6.6% compared to OPC paste, and its reinforced effect for cement-based materials was superior to carbon nanotubes. Besides, due to the excellent electrical properties of graphene nanoribbons, the sample reinforced by graphene nanoribbons had a lower electrical resistivity (135.5 Ω·m) than OPC paste (418.5 Ω·m) and paste with carbon nanotubes (175.5 Ω·m). This proved the promising application of graphene nanoribbons on cement-based materials.

• Bulletin of the Korean Chemical Society
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• v.34 no.7
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• pp.2067-2072
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• 2013

Hydrogen ($H_2$) treatment using a two-step $TiO_2$ nanotube (TONT) film was performed under various annealing temperatures from $350^{\circ}C$ to $550^{\circ}C$ and significantly influenced the extent of hydrogen treatment in the film. Compared with pure TONT films, the hydrogen-treated TONT (H:TONT) film showed substantial improvement of material features from structural, optical and electronic aspects. In particular, the extent of enhancement was remarkable with increasing annealing temperature. Light absorption by the H:TONT film extended toward the visible region, which was attributable to the formation of sub-band-gap states between the conduction and valence bands, resulting from oxygen vacancies due to the $H_2$ treatment. This increased donor concentration about 1.5 times higher and improved electrical conductivity of the TONT films. Based on these analyses and results, photoelectrochemical (PEC) performance was evaluated and showed that the H:TONT film prepared at $550^{\circ}C$ exhibited optimal PEC performance. Approximately twice higher photocurrent density of 0.967 $mA/cm^2$ at 0.32 V vs. NHE was achieved for the H:TONT film ($550^{\circ}C$) versus 0.43 $mA/cm^2$ for the pure TONT film. Moreover, the solar-to-hydrogen efficiency (STH, ${\eta}$) of the H:TONT film was 0.95%, whereas a 0.52% STH efficiency was acquired for the TONT film. These results demonstrate that hydrogen treatment of TONT film is a simple and effective tool to enhance PEC performance with modifying the properties of the original material.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.140-150
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• 2007

Thermochemical 2-step methane reforming, involving the reduction of metal oxide with methane to produce syngas and the oxidation of the reduced metal oxide with water to produce pure hydrogen, was investigated on ferrite-based metal oxide mediums. The mediums, CoFZ, CuFZ, or MnFZ, were composed of the mixture of M(M=Co, Cu or Mn)-substituted ferrite as an active component and $ZrO_2$ as a binder, respectively. The WZ medium, composed of the mixture of $WO_3$ and $ZrO_2$, was also prepared to compare. With an addition of $ZrO_2$, the surface area of the mediums was slightly increased and the sintering of active components was greatly suppressed during the reduction. The higher reactivity of the reduced mediums for water splitting was confirmed by the temperature programmed reaction. From the results of the thermochemical 2-step methane reforming, the reactivity of $CH_4$ reduction and water splitting with ferrite-based metal oxide mediums was relatively higher than that with WZ, and the order of reactivity of the mediums was MnFZ>CoFZ>CuFZ>WZ.