• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.184-186
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• 2003

In order to reduce numerical dissipation in a multi-dimensional flow, a new variable interpolation method for Roe's FDS is proposed. By introducing the Mach number weighting function w, the properties at the cell-interface are interpolated and in a non flow-aligned grid system, it can give more accurate solution because of less numerical dissipation. Various test cases including oblique contact discontinuity are simulated and compared with the results of original Roe's FDS.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.325-330
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• 2001

Shizhuyuan W-Mo-Bi-Ca $F_2$polymetallic ore is classified to the refractory one due to its complex property, fine dissemination and close association of minerals. Through several years of researches, in line with GY new mineral processing technology developed by Guangzhou Research Institute of Nonferrous Metals, in sulfide flotation circuit, an iso-flotability flowsheet is used to replace original overall bulk flotation flowsheet, and in tungsten flotation circuit, a new chelating type-GY reagent and a special pulp-conditioning system and a new technology of wolframite slime flotation are used to replace the traditional "Caustic Soda Method"$_{［1］}$, the metallurgical performance is greatly improved. Besides, GY New Method has created a favorable condition for comprehensive recovery of fluoride from tungsten flotation tailings. Notable economic benefit has been achieved.d.

• Journal of the Speleological Society of Korea
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• v.33 no.34
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• pp.7-22
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• 1993

본 연구에서는 단양지역에 분포한 석회암동굴계의 수질에 대한 주요 원소와 미량 원소 그리고 오염실태를 살펴보았다. 풍화물에 존재하는 미량 원소가 기반암보다 수 배 내지 수 백배 이상 부하되어 있었다. TSD와 EC 등은 화강암의 지하수 보다 높은 경향이 있었고 pH는 중성 내지 알칼리성이었다. Ca와 Mg은 기반암에서 용탈되어 지하수로 용존된 것으로 50ppm이상을 함유하고 있다. Fe과 K은 다른 주요 원소보다 현저히 낮은 경향이 있었다. 주요 음이온인 F$^{-}$ , Cl$^{-}$ , NO$_3$$^{-}$ , SO$_4$$^{-}$ 등은 환경기준치 보다도 현저히 낮은 상태이며, 따라서 오염이 안된 상태로 볼 수 있다. 미량 원소중 Al, Sr, Ba등이 높은 반면에 Co, Mo, Sb, Cs, W, Pb, U, Mn 등은 매우 극소량으로 존재하는 것으로 나타났다. 연구지역 중 온달굴, 고수굴, 천동, 노동 등지는 오염이 거의 안된 상태로 매우 양호한 편이나 천동굴은 관광객으로 인하여 일부 원소가 오염되어 있는 실정이다.

• Journal of Magnetics
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• v.17 no.1
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• pp.6-8
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• 2012

M$\ddot{o}$ssbauer spectra of hexagonal $BaFe_{12}O_{19}$ single crystals were studied at various temperatures (4-300 K). It was found that the spin states in Fe atoms were parallel to the ${\gamma}$-ray's direction into a single crystal along the caxis. The location of the Fe ion in the 2b site is unusual in an oxide structure and has strong anisotropic lattice vibrations. Moreover, at room temperature, the zero absorption lines of the Fe ions at the 2b site were observed due to fast diffusion motion in a double well atomic potential. The two Fe ions of the single crystal mainly enter into the sites in the mirror plane of the trigonalbipyramidal structure.

• ETRI Journal
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• v.34 no.5
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• pp.779-782
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• 2012

$CuIn_{1-x}Ga_xSe_2$ (CIGS) thin films are grown on Mo/soda lime glass using a reactive sputtering process in which a Se cracker is used to deliver reactive Se molecules. The Cu and $(In_{0.7}Ga_{0.3})_2Se_3$ targets are simultaneously sputtered under the delivery of reactive Se. The effects of Se flux on film composition are investigated. The Cu/(In+Ga) composition ratio increases as the Se flux increases at a plasma power of less than 30 W for the Cu target. The (112) crystal orientation becomes dominant, and crystal grain size is larger with Se flux. The power conversion efficiency of a solar cell fabricated using an 800-nm CIGS film is 8.5%.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.145-152
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• 2004

The flow stress value was calculated by comparing predicted and measured roll force. Using basic on-line roll force model and logged mill data the flow stress equation of high strength steel for automobile was derived. The flow stress equation consists of the flow stress equation of carbon steel and flow stress factor calculated by neural network with input parameters not only carbon contents, strip temperature, strain, and strain rate, but also compositions such as Mn, p, Ti, Nb, and Mo. Using the flow stress equation and basic roll force model, precision roll force model of high strength steel for automobile was derived. Using test set of logged mill data the flow stress equation was verified.

• Journal of Welding and Joining
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• v.13 no.3
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• pp.125-133
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• 1995

Rene80 superalloy was liquid phase diffusion bonded by using pure boron (B) as an insert material. As a basic study for the possibility of practical application of this bonding method, hardness and high temperature tensile strength of the bonded joint and metallurgical analysis were investigated. As experimental results, hardness of the bonded joint was homogenized after bonding and the tensile strength at 1144K was obtained to 90% of that of base metal. But there were some problems to be improved also, that means the joint was hardened after bonding due to increase of B content and elongation was much lower than that of base metal. Flat area and (Mo, Cr, W) boride, which should be harmful for bonding strength, were observed on the fractured surface of the tensile tested specimen.

• Journal of Korean Society on Water Environment
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• v.22 no.6
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• pp.1130-1136
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• 2006

This work elucidates the effects of pretreatment of the sewage sludge from wastewater treatment plant by microwave irradiation on elutriated acid fermentation. These experiments typically fell into two process; pretreatment as microwave irradiation and elutriated acid fermentation for hydrolysis and acidification as main process of primary sludge. The results of maximum solubilization rate of B, D primary and secondary sludge were 0.042, 0.086 and 0.15 gSCODprod./gICODin and the optimum irradiation time of microwave on 2,450 MHz and 900 W were 5 min. for primary sludge and 7 min. for secondary sludge. From batch tests on elutriated acid fermentation that was used the pretreated primary sludge as microwave, the optimum pH and HRT (hydraulic retention time) were 7 and 5 days at $35^{\circ}C$ condition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.4
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• pp.441-445
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• 1999

Thick diamond film having $~700\mu\textrm{m}$ thickness was deposited on polycrystalline molybdenum(Mo) substrate using high power (4 kW) microwave plasma-enhanced chemical vapor depostion (MPECVD) system. We could achieve free-standing diamond film via detaching as-deposited diamond film from the substrate by rapid cooling them under vacuum. We investigated the variation of photoconductivity after exposing the film surface to either oxygen or hydrogen plasma. At as-grown state, the growth side (the as-grown surface of the film) showed noticeable photoconcuctivity. The oxygen plasma treatment of this side led to the insulator. After exposing the film surface to hydrogen plasma, on the other hand, we could observe the reappearing of photoconductivity at the growth side. Based on these results, we suggest that the hydrogen plasma treatment may enhance the photoconductivity of free-standing diamond film.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.64-68
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• 2003

For the purpose of the efficient derivation of the closed-form Green's functions by which MoM matrix elements can be analytically evaluated, the optimum approximation path which is deformed from the Sommerfeld integration path on the complex $k_{\rho}$-plane is proposed based upon the steepest descent method and three level approximation procedure.