• Ceramist
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• v.21 no.2
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• pp.75-82
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• 2018

In the photovoltaics (PV) industry, there were many efforts to reduce the cost of production with high efficiency. The single most important cost factor in silicon technology is the wafer, accounting presently for ~35% of the module cost. it was already shown that the solar cell efficiency can be maintained up to the thickness range of $40-60{\mu}m$. The direct production of ultra-thin silicon wafer is very attractive and numerous different techniques, such as electrochemical process, ion implantation, and epitaxial growth, have been proposed and developed in many academic and industrial laboratories.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.9
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• pp.855-862
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• 2005

An experimental investigation has been carried out for aluminum foam heat sink inserted into the annulus to examine the feasibility as a heat sink for high performance forced water cooling in the annulus. The local wall temperature distribution, inlet and outlet pressures and temperatures, and heat transfer coefficients were measured for heat flux of 13.6, 18.9, 25.1, 31.4 $kw/m^2$ and Reynolds number ranged from 120 to 2000. Experimental results show that the friction factor is higher than clear annulus without aluminum foam, while the significant augmentation in Nu is obtained. This technique can be used for the compactness of the heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.2 no.4
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• pp.316-326
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• 1990

The measurements of heat transfer and pressure drop were performed on ripple tube with air flow. The results with the tube were compared with the performance of smooth tube. The enhancements in heat transfer coefficient for ripple tube, being compared with smooth tube, was ranged from 7.4 to 39 percent. The local Nusselt number for the inner fin tube, being compared with that for smooth tube, varied from 7.4% to 39%, while the corresponding increase in friction factors were 4.1 to 8.1%. One of the most direct indications of Nusselt number of ripple tube is given as following equation: $$Nu=0.061Re^{0.75}Pr^{0.4}(Tb/Tw)^{0.5}$$ We can see that Nusselt number for ripple tube in this experiment is consistent with the theoretical one taken from Walkinson's equation at Reynolds number range from 8,000 to 20,000.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.261-266
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• 2007

An efficient three-dimensional (3D) inversion of magnetotelluric (MT) data can be carried out by using approximate sensitivities or avoiding the calculation of a full sensitivity matrix. In this paper, we propose approximate sensitivities for efficient 3D MT inversion based on the Gauss-Newton method and test and compare four kinds of sensitivities. Applying the four sensitivities to both synthetic and field data shows that the effects of sensitivities are highly dependent on data and thus applying various combinations of sensitivities is recommended for efficient inversion and good images.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.11a
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• pp.1022-1025
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• 2017

스마트 비서 어플리케이션을 통해 하나의 앱에서 일정 관리와 날씨, 지도 및 교통 정보를 제공한다. 이를 통해 매일 반복되는 일상을 소화하는 데에 필요한 여러 종류의 정보를 얻기 위해 다양한 앱을 실행시켜야 하는 현대인들의 불편함을 없애고 편리함과 일의 효율성을 높인다.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.493-496
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• 2016

차량 전장용 소프트웨어의 안정성을 플랫폼 단계에서 테스트 및 검증을 수행하면 많은 비용이 소요된다. 본 연구에서는 플랫폼 단계에서 차량용 내장형 소프트웨어를 테스트하기 이전에 Spin 모델 검증기를 활용하여 전장용 소프트웨어의 기본단위인 타스크들의 행위를 모의 실험함으로써 시스템의 설계오류를 검증할 수 있는 도구를 개발하였다. 본 연구에서는 운영체제와 환경설정 및 제어 프로그램이 수행할 타스크들을 모델로 구축하고, 모델 검증 도구 Spin을 이용하여 타스크의 상태변화를 확인할 수 있었으며, NuSMV를 이용한 방식과 비교하여 다양한 장점들을 확인하였다.

• Journal of The Korean Astronomical Society
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• v.19 no.1
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• pp.1-9
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• 1986

We present a method for deriving most optimal filter system by which the accuracy of derived physical quantities can be maximized. Using Kurucz(1978)'s model atmospheres, an optimal four filter system for F and G dwarfs is suggested, for which mean wavelengths are located at $3400{\AA}$, $3850{\AA}$, $4190{\AA}$, and $4600{\AA}$ with half-bandwidth of $200{\AA}$. It is found that 35, 38 and 42 filters of the DDO system and the $Str{\ddot{o}}mgren$ u and $\nu$ filters are close to those of the most optimal system.

• Korean Journal of Plant Resources
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• v.21 no.6
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• pp.427-430
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• 2008

Here we reported two unrecorded naturalized species from Korean flora. Andropogon virginicus L. of Graminaeae and Euphorbia postrata Aiton of Euphorbiaceae are collected from Dong-gu, Ulsan-si and Sinjindo-ri, Taean-gun, Chungcheongnam-do respectively. A. virginicus L. was easily distinguishable from Themeda triandras var. japonica Makino by keel on glume, 2-4 racemes and long hairy rachis. Thus, the new Korean name, 'Na-do-sol-sae', was given. E. postrata Aiton was cleary distinguished from related taxa by hairs on only edges of fruits. The new Korean name, 'Nu-un-ttang-bin-dae' was given considering the species epithet. Descriptions, illustrations and photographs showing habitat were given.

• Communications of the Korean Mathematical Society
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• v.38 no.3
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• pp.755-772
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• 2023

Our aim is to establish certain image formulas of the (p, q)-extended modified Bessel function of the second kind M_ν,p,q(z) by employing the Marichev-Saigo-Maeda fractional calculus (integral and differential) operators including their composition formulas and using certain integral transforms involving (p, q)-extended modified Bessel function of the second kind M_ν,p,q(z). Corresponding assertions for the Saigo's, Riemann-Liouville (R-L) and Erdélyi-Kober (E-K) fractional integral and differential operators are deduced. All the results are represented in terms of the Hadamard product of the (p, q)-extended modified Bessel function of the second kind M_ν,p,q(z) and Fox-Wright function _rΨ_s(z).

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.1400-1403
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• 2007

최근 학교 교육 현장에서는 교수-학습의 효과 극대화를 위하여 교육정보화 사업이 추진되고 있다. 이를 위하여 교육인적자원부는 컴퓨터 기반 수업(CAI)을 지원하고 특히 학습자가 인지적 구조를 구성할 수 있는 학습 환경 조성을 위해 우수한 교육용 소프트웨어를 개발 보급하여 활용할 수 있도록 지원하고 있다. 그런데 학교 현장에서는 소프트웨어 구입에 따라 매년 그 보유수가 늘어나고 있으며, 이에 따른 효율적인 교육용 소프트웨어 관리의 필요성이 증가되고 있다. 따라서 본 논문에서는 교육용 소프트웨어를 교수 학습용 소프트웨어, 업무 지원용 소프트웨어, 시스템 관리 소프트웨어 3가지로 분류하여 등록하고 사용자별 사용 구분을 두어 보다 효과적으로 시스템을 사용할 수 있는 XML 기반 관리 시스템을 제안한다.