• 자원리싸이클링
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• 제12권6호
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• pp.47-56
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• 2003

PVC를 열분해시켰을 때에 방출되는 염화수소와 전기로 제강공정에서 발생하는 분진을 반응시켜 PVC의 염소와 분진에 함유되어있는 유가금속을 염화물로 회수하기 위해 국내 I 사와 P 사의 전기로 제강공정에서 분진을 채취하여 물성을 조사하고, 순수한 PVC 분말과 분진을 혼합하여 펠릿을 제조한 후에 이를 $300^{\circ}C$에서 가열하여 생성되는 염화물과 펠릿의 상태를 조사하였다. 분진의 주 구성 광물은 zincite와 franklinite였으며, I dust와 P dust에 함유되어있는 아연중에서 각각 약 50%와 48%가 zincite로 존재하고 있는 것으로 나타났다. 펠릿은 30$0^{\circ}C$에서 15분 이상의 가열로 PVC 분말의 모든 염소가 방출되었으며, 방출된 염화수소는 20%의 PVC 혼합량까지는 거의 전량이 분진과 반응하여 염화물을 형성하였다. 염화수소와의 반응은 zincite의 반응속도가 franklinite보다 빨라서 먼저 반응하고 이후의 남은 염화수소가 franklinite와 반응하므로 염화철(III)이 생성되지 않기 위한 PVC의 혼합량은 zincite의 양에 좌우된다.

• 한국재료학회지
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• 제14권11호
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• pp.755-763
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• 2004

A stoichiometric mixture of evaporating materials for $CuInse_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuInse_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $620^{\circ}C\;and\;410^{\circ}C$, respectively. The temperature dependence of the energy band gap of the $CuInse_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_{g}(T)=1.1851 eV - (8.99{\times}10^{-4} eV/K)T^2/(T+153 K)$. After the aa-grown $CuInse_2$ single crystal thin films was annealed in Cu-, Se-, and In-atmospheres, the origin of point defects of $CuInse_2$ single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of $V_{cu},\;V_{Se},\;Cu_{int},\;and\;Se_{int}$ obtained by PL measurements were classified as a donors or accepters type. And we concluded that the heat-treatment in the Cu-atmosphere converted $CuInse_2$ single crystal thin films to an optical n-type. Also, we confirmed that In in $CuInse_2$/GaAs did not form the native defects because In in $CuInse_2$ single crystal thin films existed in the form of stable bonds.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.226-229
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• 2004

A stoichiometric mixture of evaporating materials for $CuAlSe_2$ single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, $CuAlSe_2$ mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuAlSe_2$ single crystal thin films measured with Hall effect by van der Pauw method are $9.24{\times}10^{16}\;cm^{-3}$ and $295\;cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the $CuAlSe_2$ obtained from the absorption spectra was well described by the Varshni's relation, $E_g(T)\;=\;2.8382\;eV\;-\;(8.68{\times}10^{-4}\;eV/K)T^2/(T+155K)$. The crystal field and the spin-orbit splitting energies for the valence band of the $CuAlSe_2$ have been estimated to be 0.2026 eV and 0.2165 eV at 10K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the ${\Delta}so$ definitely exists in the ${\Gamma}_5$ states of the valence band of the $CuAlSe_2$. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.179-182
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• 2004

The $p-CdIn_2Te_4$ single crystal was grown in the three-stage vertical electric furnace by using Bridgman method. The quality of the grown crystal has been investigated by the x-ray diffraction and the photoluminescence measurements. From the Photoluminescence spectra of the as-grown $CdIn_2Te_4$ crystal and the various heat-treated crystals, the $(D^{o},X)$ emission was found to be the dominant intensity in the photoluminescence spectrum of the $CdIn_2Te_4:Cd$, while the $(A^{o},X)$ emission completely disappeared in the $CdIn_2Te_4:Cd$. However, the $(A^{o},X)$ emission in the photoluminescence spectrum of the $CdIn_2Te_4:Te$ was the dominant intensity like an as-grown $p-CdIn_2Te_4$ crystal. These results indicated that the $(D^{o},X)$ is associated with $V_{Te}$ acted as donor and that the $(A^{o},X)$ emission is related to $V_{Cd}$ acted as acceptor, respectively. The $p-CdIn_2Te_4$ crystal was found to be obviously converted into the n-type after annealing in the Cd atmosphere. The origin of $(D^{o},\;A^{o})$ emission and its TO Phonon replicas is related to the interaction between donors such as $V_{Te}$ or $Cd_{int}$, and accepters such as $V_{Cd}$ or $Te_{int}$. Also, the In in the $CdIn_2Te_4$ was confirmed not to form the native defects because it existed in the stable form of bonds.

• 한국세라믹학회지
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• 제47권6호
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• pp.583-589
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• 2010

In this paper, the properties of reclaimed ash(RA) from various domestic thermal power plants(S, D and H) were analyzed, and the possibility of fabricating the artificial lightweight aggregate(ALA) using RA was studied. The chemical compositions of RA are similar to the clay, but it had higher concentrations of alkali earth metal oxides(CaO, MgO) and unburned-carbon. The TCLP(Toxicity Characteristic Leaching Procedure) results showed that the dissolution concentrations of heavy metal ions of RA were below the limitation defined by the enforcement regulation of wastes management law in Korea. The results of IC analysis showed that leaching concentration of $Cl^-$ ion was 124 ppm for RA of HN and ${SO_4}^{2-}$ ion was leached a few hundreds ppm for all RA in this study. The ALAs with various mass ratio of clay to reclaimed ash(RA:Clay = 7:3, 6:4, 5:5, 4:6, 3:7) were sintered with a electric muffle furnace at the temperature of $1050{\sim}1200^{\circ}C$. The specific gravity and water absorption(%) of the sintered ALAs were 1.1~1.8 and 10~30% respectively. The ALA sintered in the rotary kiln at $1125^{\circ}C$ showed a bulk density of 1.7 and water absorption of 15.2%.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.267-273
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• 2012

Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. And the new type of double-layer absorber-the front layer, porous metal foam which absorbs the radiation and transfers the heat from material to gas, and the back layer, catalytically-activated metal foam-was prepared, and its activity was tested by using electric furnace. Ni was applied as the active metal on the gamma-Al2O3 coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically activated metal foam absorber, this new type of double layer absorber is found to exhibit a superior reaction and thermal storage performance at the fluctuating incident solar radiation. In addition, unlike direct irradiation of the foam absorber, double layer absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 3.25kW and the maximum CH4 conversion was almost 59%.

• 한국세라믹학회지
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• 제32권10호
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• pp.1169-1177
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• 1995

Barium nitrate and yittrium nitrate were dissolved into distilled water. Titaium hydroxide precipitated from titanium chloride with NH4OH was dissolved into nitric acid. Each aqueous solution was mixed for 12 hr in the composition of Ba1-xYxTiO3 (x=0.1∼0.6) and the concentration of mixed solution was 0.1 mol/ι. The mixed solution was sprayed with an ultrasonic atomizer and carried into an electric furnace which was kept at 900∼1000$^{\circ}C$ and pyrolyzed. Pyrolyzed powders were collected on the glass filter with vacuum pump. Aqueous Mn solutiion was added into the synthesized powders, mixed with ultrasonic vibration and sintered at 1300∼1400$^{\circ}C$. Synthesized powders were characterized with SEM, XRD, DT-TGA, and BET. Microsture and resistivity of sintered body were investigated with SEM and multimeter. The results of this experiment were as follows; 1) Yittrium dooped BaTiO3 powders were synthesized above 950$^{\circ}C$. 2) The average particle sizes of powders from BET specific surface area and SEM were 0.045$\mu\textrm{m}$, 0.046$\mu\textrm{m}$ respectively. The particle size distribution was narrow in the range of 0.1∼1.0$\mu\textrm{m}$ from SEM. 3) Room temperature resistivity and pmax/pmin of 0.4 mol% Y doped specimen which was sintered at 1375$^{\circ}C$ were 102∼3 (Ω$.$cm) and 102∼3 respectively. 4) Room temperature resistivity and pmax/pmin of 0.4 mol% Y and 0.04 at% Mn added specimen which was sintered at 1375$^{\circ}C$ were 102∼3 (Ω$.$cm) and 106∼7 respectively. 5) Grain growth was inhibited with addition of Y2O3 and enhanced in addition of Mn by 0.05 atm%.

• 한국세라믹학회지
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• 제23권1호
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• pp.51-59
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• 1986

It was the first time the MgO-C brick was developed for the lining materials in the hot spots in electric are furnace in 1972. MgO-C brick is high registant to thermal and structural spalling. Futhermore for the reason that carbon is hard to react with slag and MgO is high fireproof MgO-C brick shows a high corrosion registance to slag attack compared with conventional basic refractories. Owing to their excellent properties the use of MgO-C refractories are being developed widely in the field of shaped refractories and even in that of monolithic refractories. In this paper the oxidation of carbon the infiltration of slag into the brick texture and effects of additions were investigated. The results obtained were as follows : 1) The use of fused MgO-clinker and high purity carbon as raw materials increased the corosion registance and hot modulus of rupture of MgO-C brick. 2) As the oxidation reaction of the carbon proceeded the slag infiltrated into the brick texture. And then the slag components reacted with the MgO grains and formed low melting point compounds particulary CaO.MgO.$SiO_2$ and 3CaO.MgO.$2SiO_2$ that resulted in the wear of the brick. 3) It is recongnized the Al, Si, $B_3C$ effects on the oxidation registant properties of MgO-C brick by contribu-ting to the decrease of permeability according to the formation of $Al_4C_3$, SiC, $B_2O_3$ and the decrease of open pores relating to the formation of MgO.Al2O3, $SiO_2$, 3MgO.$B_2O_3$ at the decarbonized layer.

• 대한치과기공학회지
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• 제33권4호
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• pp.263-270
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• 2011

Purpose: The grindability of binary Ti-X%Zr(X=10,20,40) alloys in order to develop a Ti alloy with better machinability than unalloyed titanium has been evaluated. Methods: Experimental Ti-Zr alloys were made in an argon-arc melting furnace. Slabs of experimental alloys were ground using a SiC abrasive wheel on an electric handpiece at circumferential speeds(12000,18000,25000 or 30000rpm) by applying a force(200gr). Grinding rate was evaluated by measuring the amount of metal volume removed after grinding for 1 minute and the volume ratio of metal removed compared to the wheel material lost, which was calculated from the diameter loss (grinding ratio). Experimental datas were compared to those for cp Ti(commercially pure titanium) and Ti-6%Al-4%V alloy were used controls. Results: It was observed that the grindability of Ti-Zr alloys increased with an increase in the Zr concentration. More, they are higher than cp Ti, particularly the Ti-20%Zr alloy exhibited the highest grindability at all circumferential speeds. There was significant difference in the grinding rate and grinding ratio between Ti-20%Zr alloy and cp Ti at any speed(p<0.05). Conclusion: By alloying with Zr, the Ti exhibited better grindability at all circumferential speeds. the Ti-20%Zr alloy has a great potential for use as a dental machining alloy.

• 한국주조공학회지
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• 제18권4호
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• pp.383-388
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• 1998

Effects of $CaCN_2$ addition on the grain refinement in the AM60 magnesium ingots were investigated. The effects of the $CaCN_2$ are estimated with different inoculation temperatures, inoculation contents, and holding time to find out the optimum condition. AM60 alloy was melted in the low carbon steel crucible by cylindrical electric furnace under an argon atmosphere. The melting and casting apparatus is specially designed for magnesium alloys. The grain size of AM60 magnesium alloy decreased significantly with an increase in $CaCN_2$ content and, at 0.8 wt% $CaCN_2$ or more, grain size becomes constant at about $85 {\mu}m$. The optimum condition was obtained in the 0.8 wt% $CaCN_2$ for holding molten metal of 30 min. at the temperature of $710^{\circ}C$. The tensile properties of AM60 magnesium alloys were improved due to grain refinement by addition of $CaCN_2$. In the optimum condition, the yield strength, tensile strength and elongation were ${\sigma}_{0.2}=107 MPa$, ${\sigma}_{T.S}=234 MPa$ and e=14.2%. The variation of stress with strain obeyed the relationship of the ${\sigma}=K{\varepsilon}^n$. The strain-hardening exponent, n and strength coefficient, K obtained in the 0.8 wt% $CaCN_2$ added AM 60 magnesium alloy were n=0.21 and K=390 MPa.