• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.431-438
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• 1996

Transmission electron microscopy has been used to investigate the microstructure of hot-pressed $TiB_{2}$. Thin foil specimens, prepared by conventional ion beam thinning, revealed many features which originated from the crystallographic anisotropy of hexagonal $TiB_{2}$. It was observed that in these specimens Fe-impurities are precipitated to form secondary Fe-rich phases at grain triple edges, in grain boundaries and sometimes in-grain. These Fe-rich precipitates were characterised by their coherence or semi-coherence to a favourably oriented grain at a grain triple edge or grain boundaries or to the matrix $TiB_{2}$ phase.

• 한국벤처창업학회:학술대회논문집
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• 2023.11a
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• pp.85-89
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• 2023

최근 급변하는 세계 경제 환경에서 창업기업은 혁신, 고용 및 경제 활력의 핵심 동력으로 등장했다. 그러나 초기 창업 기업이 성장하는 여정에는 많은 어려움이 따르며, 이 과정에서 엔젤투자자의 역할이 필수적이다. 초기 창업 시장의 촉매제 역할을 하는 엔젤투자자는 필요한 자본을 제공할 뿐만 아니라 경영 노하우 및 네트워크를 통해 창업기업이 성공할 수 있도록 지원한다. 그러나 최근 데이터에 따르면 신생 기업 중 엔젤 투자의 혜택을 받는 기업은 1.4%에 불과한 것으로 나타나 창업기업의 잠재력과 지원 사이에는 분명한 공백이 존재한다. 이 연구는 지속가능한 경제 성장을 위해 창업 생태계의 중요한 요소인 엔젤투자자의 위험회피 성향을 이해함으로써 이들의 투자 행동, 의사결정 프로세스에 대한 통찰력을 얻을 수 있다. 위험회피가 엔젤투자에 미치는 영향을 알아보고 엔젤투자가 활성화 될 수 있는 방법을 제안하고자 한다. 본 연구를 통해 위험회피 성향이 엔젤투자에 대한 관심도와 실제 투자 활동 간의 관계를 추정해보고자 한다. 위험회피 성향이 엔젤투자자에 어떻게 영향을 미치는지 탐색하는 것에 중점을 두고, 엔젤투자자의 행동과 관심사에 영향을 미치는 다양한 요인들을 포함하여 진행한다. 연구 표본은 서울 및 경기 지역의 일반 성인과 엔젤투자자로 설문조사를 통해 필요한 데이터를 수집한다. 이 연구는 위험회피 성향이 엔젤투자 결정에 어떻게 반영되는지에 대한 깊은 이해를 제공하고, 엔젤투자 활성화를 위한 정책 및 전략을 수립하는데 중요한 통찰력을 제공할 것이다.

• Journal of Digital Convergence
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• v.19 no.7
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• pp.113-127
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• 2021

This study classifies review attributes into ratings, number of comments and image information in online shopping mall to verify their impact on brand attitude and purchase decision and e-WOM intention. Use SPSS 23.0 for frequency analysis, factor analysis and regression analysis. The results showed that review attributes have a positive effect on brand attitudes, purchase decision and e-WOM intention, but the number of comments has not affect on purchase decision. Brand attitude has a positive effect on purchase decision and e-WOM intention. Brand attitude has media effect in the relationship between ratings, image information and purchase decision, and in the relationship between review attributes and e-WOM intention. As these results, consumers don't always like to have a lot of comments. and should allow to focus on high ratings and photo reviews as much as possible when writing reviews.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.6
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• pp.242-247
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• 2008

The glass and glass-ceramics containing EAF dust $30{\sim}70\;wt%$ were fabricated and the dependance of physical properties upon crystal phases and microstructure formed was studied. The crystallization behavior of glass and glass-ceramics containing various contents of EAF dust composing of mainly $Fe_2O_3$ and ZnO was analyzed by crystal identification and microstructure observation. The glass specimen with EAF dust 30 wt% showed a typical amorphous pattern in XRD results and the specimen with above 30 wt% EAF dust had some un-dissolved crystals which was originated from EAF dust. The all glass-ceramics had franklinite, willemite and augite crystal phases. The density of glass-ceramics was higher than that of same composition glass, and it increased with EAF dust contents. In addition, the thermal and mechanical properties of glass-ceramics were always higher than those of glasses. In other words, the thermal expansion coefficient of glass increased with EAF dust contents while it decreased for the glass-ceramics. The vickers hardness for the glass and glass-ceramics increased with EAF dust content, the glass-ceramics always being higher those of glass of same composition.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.4
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• pp.178-182
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• 2012

The grain growth is very important because of its great influence on the various materials properties. Therefore, in this study, the effects of anisotropic grain boundary energy on grain growth in 2-D have been investigated with a large scale phase field simulation model on PC. A $2000{\times}2000$ grid system and the initial number of grains of about 73,000 were used in the computer simulation. The anisotropic ratio of grain boundary energy, ${\sigma}_{max}/{\sigma}_{min}$, has been varied from 1 to 3. As the anisotropy increased, the grain growth exponent, n, increased from 2.05 to 2.37. The grain size distribution showed a central plateau in the isotropic case, and was changed into no central plateau and the increasing population of very small grains in the anisotropic case, resulting from slowly disappearing grains. Finally, simulated microstructures were compared according to anisotropy.

• Korean Journal of Materials Research
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• v.11 no.7
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• pp.545-549
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• 2001

Glass-ceramics were prepared and evaluated for the properties to expand the scope of application of the rare earth aluminosilicate glasses, A glass-ceramic added with $TiO_2$as a nucleating agent, which was crystallized internally and it was characterized for physical, thermal and mechanical properties of crystal and residual glass in the glass-ceramic, X-ray diffractometer reveals an unknown crystal as $Nd_{4.6}Si_{7.6}Al_{4.0}Ti_{2.4}O_{32}$ which was found in surface and internal crystals dependent on composition and heat treatments. The thermal expansion coefficients of glass-ceramics were $5.4~6.2{\times}10^{-6}/^{\circ}C$, which increased with increasing crystal growth. Considering that the hardness and the elastic constant of crystal in glass-ceramics are 12GPa and 220GPa, respectively, the application of the glass-ceramics would be applicable for structural materials at elevated temperature.

• Journal of the Korean Vacuum Society
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• v.12 no.2
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• pp.130-135
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• 2003

Polycrystalline silicon thin films have been used for low cost thin film device application. However, it was very difficult to fabricate high performance poly-Si at a temperature lower than $600^{\circ}C$ for glass substrate because the crystallization process technologies like conventional solid phase crystallization (SPC) require the number of high temperature (600-$1000^{\circ}C$) process. The objective of this paper is to grow poly-Si on flexible substrate using a rapid thermal crystallization (RTC) of amorphous silicon (a-Si) layer and make the high temperature process possible on molybdenum substrate. For the high temperature poly-Si growth, we deposited the a-Si film on the molybdenum sheet having a thickness of 150 $\mu\textrm{m}$ as flexible and low cost substrate. For crystallization, the heat treatment was performed in a RTA system. The experimental results show the grain size larger than 0.5 $\mu\textrm{m}$ and conductivity of $10^{-5}$ S/cm. The a-Si was crystallized at $1050^{\circ}C$ within 3min and improved crystal volume fraction of 92 % by RTA. We have successfully achieved a field effect mobility over 67 $\textrm{cm}^2$/Vs.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.584-594
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• 1996

For the separation and purification of aluminium chloride hexahydrate crystals from kaolin leaching solution the effects of crystallization conditions, such as crystallization temperature, concentration of aluminium chloride concentration in the leaching solutin and gas flow rate of HCl into the leaching solution, on purity of the aluminium chloride hexahydrate crystals were investigated. The supersaturation level of aluminium chloride in the leaching solution gave great influence on the purity of the crystals. When supersaturated concentration of the aluminium chloride in the leaching solution was generated in low level, the aluminium chloride hexahydrate crystals were produced with high purity ; that is, the crystals hving a low Fe-ion concentration. The supersaturation level of aluminium chloride in the leaching solution was mainly determined by crystallization temperature, concentrations of aluminium chloride and hydrochloric acid in the solution. However, in spite of changes of the above crystallization coditions, a needle shape morphology of aluminium chloride hexahydrate crystals did not modified. To measure hydrochloric acid concentration in the kaolin leaching solution, we applied the oxalate titration method, which was suggested by shank [9] and it was prove that this method could titrate hydrochloroic acid concentration in multi-component ionic solution such as kaolin leaching solution.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.6-13
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• 1999

NaX zeolite crystal were grown from seed elements of synthetic NaX(2~3$\mu\textrm{m}$) Powder in a mother liquor having an approximate reactant composition ${4.12{Na}_{2}O{\cdot}{Al}_{2}{O}_{3}{\cdot}3.5{SiO}_{2}{\cdot}593{H}_{2}O$.The result was that crystallization time of NaX zeolite was reduced with adding seed materials to the initial mixture and crystal size was reduced . but with increasing crystallization time, NaX zeolite. In this study, We investigated detailed factors which NaX crystal has been determined by a combination of SEM, XRD, FT-IR, and BET.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.5
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• pp.218-223
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• 2001

The chemical-mechanical polishing process was carried out for 2"-dia. sapphire wafer grown by horizontalBridgman method on the urethane lapping pad with the silica sol. The polished wafer shows the full-width at halfmaximum of 200~400 arcsec in double-crystal X-ray diffraction, indicating that the slicing, grinding and lapping processes before the polishing process affected the crystalline structural property of the wafer surface by the mechanical residual stress. For the inclusion of surface treatments after chemical-mechanical polishing such as the thermal annealing at the temperature of $1,200^{\circ}C$for 4 hrs. and chemical etching, the crystalline quality was sigdicantly enhanced with the reduced full-width at half maximum up to 8.3 arcsec.arcsec.