• Bulletin of the Korean Chemical Society
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• 제32권12호
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• pp.4371-4376
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• 2011

In this work, we investigate the growth behavior of silicon oxide nanowires via a solid-liquid-solid process. Silicon oxide nanowires were synthesized at $1000^{\circ}C$ in an Ar and $H_2$ mixed gas. A pre-oxidized silicon wafer and a nickel film are used as the substrate and catalyst, respectively. We propose two distinctive growth modes for the silicon oxide nanowires that both act as a unique solid-liquid-solid growth process. We named the two growth mechanisms "grounded-growth" and "branched-growth" modes to characterize their unique solid-liquid-solid growth behavior. The two growth modes were classified by the generation site of the nanowires. The grounded-growth mode in which the grown nanowires are generated from the substrate and the branchedgrowth mode where the nanowires are grown from the side of the previously grown nanowires or at the metal catalyst drop attached at the tip of the nanowire stem.

• 한국재료학회지
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• 제14권2호
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• pp.83-89
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• 2004

SiC nanotubes were synthesized by SLS growth mechanism using various metal catalysts. Synthesized nanotubes had mean diameters of 20~50 nm and several $\mu\textrm{m}$ length. The kind of catalysts affected microstructures of SiC nanotubes by different diffusion routes. These differences are attributed to catalysts' physical properties and relative activities to the graphite substrate. Fe acted as a good catalyst of SLS growth mechanism. But in case of Ni, SiC nanotubes grew slowly. Optical property was measured by photoluminescence measurement. Relatively broad peak was obtained and mean peak positioned at about 430 nm. This result was the same as other nanocrystalline SiC materials, but was different from the results of bulk SiC probably due to quantum confinement effect and defect in the grown SiC nanotube.

• 한국결정성장학회지
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• 제14권4호
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• pp.174-186
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• 2004

Striations are growth-induced inhomogeneities which hamper the applications of solid-solution crystals and of doped crystals in numerous technologies. Thus the optimized performance of solid solutions often can not be exploited. The inhomogeneity problem can be solved in specific cases by achieving a distribution coefficient one in growth from melts and from solutions. Macrostep-induced striations can be suppressed by controlling the growth mode, by achieving growth on facets thereby preventing step bunching. Thermal striations are commonly assumed to be caused by convective instabilities so that reduced convection by microgravity or by damping magnetic fields was and is widely attempted to reduce such inhomogeneities. Here it will be shown that temperature fluctuations at the growth interface cause striations, and that hydrodynamic fluctuations in a quasi-isothermal growth system do not cause striations. The theoretically derived conditions were experimentally established and allowed the growth of striation-free crystals of $KTa_{1-x}Nb_xO_3$"KTN" solid solutions. Hydrodynamic variations from the accelerated crucible rotation technique ACRT did not cause striations as long as the temperature was controlled within $0.03^{\circ}$ at $1200^{\circ}C$ growth temperature. Alternative approaches to solve or reduce the segregation and striation problems in growth from melts and from solutions are discussed as well.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.19-26
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• 2004

The growth of solid particles in TiC-XC-2vo1.% and TiC-XC-30vo1.% Ni alloys, (where X=Zr, W or Mo) was fitted to the equation of the form $d^3$-${do}^3$=Kt during the liquid phase sintering at 1,673K. Also, the grain growth behavior decreased markedly with the addition of ${MO}_2$C or WC and increased with the addition of zrC. The contiguity was greater in the alloys with a smaller growth rate constant and especially, decreased by increasing the Ni content in the TiC-${MO}_2$C-Ni alloy. In addition, the effect of the addition of carbide on the grain growth of 2 vo1.% Ni alloys was found to be similar to that of 30vo1.% Ni alloys. Consequently, the grain growth mechanism cannot be explained by the usual solution / reprecipitation process, but can be explained in terms of a new growth velocity equation, which includes the effects of contiguous carbide grain boundaries in restricting the overall grain growth, as well as the area of the solid / liquid interface in the alloy.

• 대한기계학회논문집B
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• 제27권2호
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• pp.265-273
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• 2003

Numerical analysis of bubble motion during nucleate boiling is performed by imposing a constant heat flux condition at the base of a heater which occurs in most of boiling experiments. The temporal and spatial variation of a solid surface temperature associated with the bubble growth and departure is investigated by solving a conjugate problem involving conduction in the solid. The vapor-liquid interface is tracked by a level set method which is modified to include the effects of phase change at the interface, contact angle at the wall and evaporative heat flux in a thin liquid micro-layer. Based on the numerical results, the bubble growth pattern and its interaction with the heating solid are discussed. Also, the effect of heating condition on the bubble growth under a micro-gravity condition is investigated.

• 한국산림과학회지
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• 제95권3호
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• pp.358-364
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• 2006

송이균의 환경조건에 따른 생장특성을 구명하고자 송이균을 고체매질을 이용하여 배양하였다. 고체매질에서의 송이균의 생장량은 에르고스테롤 함량을 분석하여 비교하였다. 송이균의 배양에 적합한 고체매질은 펄라이트와 마사토로 나타났으며 곡물 영양분으로는 보리가 우수하였다. 적정화된 고체배지에서 송이균의 생장은 송이균의 접종 후 2주부터 급격히 생장하였으며 8주 경에 최고의 생장량을 나타냈다. 송이균 배양에 적합한 수분함량은 30~70%였으며 부엽토 첨가(10%)가 생장에 더욱 양호하였다. 이러한 결과는 송이산지에서 토양유기물이 적절히 있고 토양수분이 높을 때에 송이균의 생장이 왕성할 것으로 추정할 수 있다. 고체배지에서 송이균사체를 접종 후 2주부터 급격히 생장하였으며 8주 경에 최고의 생장량을 나타냈다. 이러한 고체매질은 앞으로 송이 균사체의 생리연구에 이용될 수 있을 것이다.

• 한국수산과학회지
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• 제49권2호
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• pp.168-175
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• 2016

We conducted a 90-day feeding experiment to evaluate the growth and energy budget of the sea cucumber Apostichopus japonicus. Sea cucumbers with a mean initial wet body weight of 3.03±0.06 g were fed one of the following three diets: an eel fecal solid diet, rainbow trout fecal solid diet, or a commercial diet at a water temperature of 17±1℃ and salinity of 32±1 psu. The results suggested that the diets affected the final body weight, specific growth rate (SGR), food ingestion, feces production ratio, and hence the growth and energy budget of the sea cucumbers. Sea cucumbers fed the eel and rainbow trout fecal solid diets showed poorer energy absorption, assimilation, and growth than those fed the commercial diet. The sea cucumbers fed the commercial diet had a significantly higher SGR and proportion of energy used for growth than those fed the other two diets. Sea cucumbers fed the rainbow trout fecal solid diet showed a comparatively higher ingestion rate and feces production ratio than those fed the commercial diet. The eel and rainbow trout fecal solid diets, therefore, were not suitable for sea cucumbers in intensive cultivation. Our findings will facilitate further development of more appropriate diets for culture of sea cucumber.

• 한국화재소방학회논문지
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• 제25권5호
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• pp.62-68
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• 2011

본 연구는 고체가연물의 초기 점화 및 화재성장과정에서의 발열량을 정량적으로 측정하고 가연물에 따른 화재성장특성 파악하고자 한다. 실험에 적용된 고체가연물은 단일/이중 목재크립, 단일/이중 쿠션, 카페트/목재크립이며 화재발달 단계에서 화재성장특성을 시간 제곱 화재성장 시나리오와 비교분석하고 고체가 연물의 화재성장 계수를 정량화 하였다. 고체가연물의 연소과정에서 소모되는 연료의 질량과 방출되는 총열에너지 개념을 이용하여 가연물의 평균 유효연소율을 평가하였으며 환기 및 화재조건의 영향을 분석하여 화재해석시 화재시나리오를 설정하는데 있어서 실질적인 정보를 제공하고자 한다.

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1354-1358
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• 2005

Nano- and microstructured indium nitride crystals were synthesized by the reaction of indium oxide ($In_2O_3$) powder and its pellet with ammonia in the temperature range 580-700 ${^{\circ}C}$. The degree of nitridation of $In_2O_3$ to InN was very sensitive to the nitridation temperature. The formation of zero- to three-dimensional structured InN crystals demonstrated that $In_2O_3$ is nitridated to InN via two dominant parallel routes (solid ($In_2O_3$)-to-solid (InN) and gas ($In_2O$)-to-solid (InN)). The growth of InN crystals with such various morphologies was explained by the vapor-solid (VS) mechanism where the degree of supersaturation of In vapor determines the growth morphology and the vapor was mainly by the reaction of $In_2O$ with ammonia and partially by sublimation of solid InN. The pellet method was proven to be useful to obtain homogeneous InN nanowires.

• 한국건설순환자원학회논문집
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• 제8권4호
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• pp.475-482
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• 2020

본 연구에서는 결정성장형 자기치유 고상캡슐의 코어조성비에 따라 3수준의 고상캡슐을 제조하였으며, 결정성장형 자기치유 고상캡슐을 혼합하여 시멘트 모르타르를 제조하였다. 제조된 고상캡슐은 시멘트 질량의 3%와 혼합하여 시멘트 모르타르의 균열 유도 재령에 따른 치유 특성을 평가하였다. 결정성장형 자기치유 고상캡슐을 혼합한 시멘트 모르타르의 균열 유도 재령에 따른 균열치유 특성을 평가한 결과, 7일 재령 동안 반응하지 않은 수화물질이 남아있기 때문에 고상캡슐과 혼합된 시멘트 모르타르의 자기치유 성능은 28일 재령 대비 7일 재령이 증가한 것으로 나타났다.