• KSBB Journal
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• 제20권5호
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• pp.350-354
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• 2005

수소생산을 최적화하기 위하여 Enterobacter cloacae YJ-1을 이용해 생산성에 미치는 탄소원 농도, 질소원 농도, 금속이온 농도, 아미노산 효과로서 회분식 배양을 통하여 실험을 수행하였다. 각종 탄소원의 종류에 따라 수소생산을 검토한 결과 glucose 첨가시에 가장 양호하였다. 따라서 glucose 농도를 변화시켜 수소생산량을 조사한 결과 $2\%$(w/v) 농도에서 최대를 보여 975.4 mL/L를 생산하였다. 각종 질소원 중에서 가장 효과적인 질소원은 yeast extract이었으며, 최대 수소생산량은 $1.5\%$(w/v) 농도에서 1651.5mL/L이었다. 금속이온으로는 $Na_2MoO_4$가 가장 효과적으로 나타나 $0.04\%$(w/v) 농도에서 1753.3 mL/L를 생산하였다. 아미노산은 cystein에서 가장 생산량이 많았으며, 다음은 proline, histidine, alanine 등 순이었다. 회분식 배양의 최적 조건하에 수소를 연속적으로 생산하기 위하여 반연속배양을 행한 결과 $3\%$ (w/v) 농도에서 2215.4 mL/L로 가장 높았다. 생산균주의 대사에 관한 물질을 보다 세밀히 조사하고 연속적인 수소생산을 살펴 산업적인 공정개발도 가능하리라 생각된다.

• 국토계획
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• 제54권3호
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• pp.63-74
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• 2019

Korean government has implemented policies to strengthen the competitiveness of small and medium sized cities. However, since it is often difficult to enhance the competitiveness through individual projects, many local governments in metropolitan areas are working together to pursue local growth. On the other hand, small and medium sized cities that are not included in metropolitan areas due to their spatial limitations have difficulties in implementing effective growth policies. Given this background, the purpose of this study is to identify the functional correlation based on urban interactions and develop functional econometric model for the economic growth of small and medium sized cities. This study uses spatial econometrics models and functional weight matrix to identify the effects of functional networks on small and medium sized cities. The results show the effect of functional networks on the growth of small and medium sized cities and provide policy implications for regional spatial planning that addresses effective management of small and medium sized cities.

• 산학경영연구
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• 제13권
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• pp.159-178
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• 2000

본 연구는 우리나라 법인세제 하에서 기업규모와 기업특성 및 조세지원제도에 따라 발생하는 조세부담의 차이에 대한 실증적인 점증을 하고자, 상장 대기업과 중소기업을 대상으로 유효법인세율로 측정되는 조세부담의 차이가 기업의 규모 및 업종별로 어떤 차이가 있는지를 분석하였다. 선행연구를 검토하면서 우리나라 조세지원제도를 설명하였으며, 조세지원제도의 효과와 기업특성에 대한 가설을 설정한 다음 T-검정을 실시하였다. 연구결과를 요약하면 첫째, 조세지원에 따른 세액공제가 법인의 조세부담율에 실질적 영향을 미쳤으며 이는 조세지원제도의 유효성을 입증한 결과이며, 둘째, 중소기업에 대한 조세지원제도가 어느 정도 유효하다고 판단되었으며, 셋째, 제조업에 대한 조세지원제도도 어느 정도 유효한 것으로 나타나 종합적으로 조세지원제도는 그 목적을 어느 정도 달성하고 있는 것으로 나타난다. 하지만 법인세부담율에 영향을 주는 기타 요인(수출, 투자, 증자 등)을 반영하지 못하였고, 익금산입이나 손금산입등의 세무조정 내용을 반영하지 못한 점, 또한 단일연도의 자료만을 이용한 점등을 그 한계로 지적할 수 있다.

• 식물조직배양학회지
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• 제27권6호
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• pp.479-484
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• 2000

시클라멘의 급속증식체계를 확립하기 위하여 발아 후 자엽이 전개된 어린 식물체의 괴경, 자엽, 엽병 등의 절편을 분리하여 절편부위별로 캘러스 및 기관분화에 미치는 생장조절제의 종류와 농도에 따른 식물체의 생장반응을 조사하였다. 절편부위별 캘러스 형성 및 shoot분화에 있어서 auxin류 단용처리의 경우 괴경절편의 NAA처리구에서 절편으로부터 캘러스 없이 shoot가 직접 발생하여 가장 양호하였으며, 1개의 절편체에서 10개 이상의 다아체가 분화되었다. 자엽이나 엽병절편은 캘러스만 유도되었고 대부분 치상당시의 상태로 shoot 발생에 auxin류의 처리는 부적합하였다. Cytokinin류 단용처리는 1.0 mg/L TDZ처리구에서 괴경의 경우 100％ shoot 분화율을 보였고, 자엽절편 역시 배양 40일경부터 다수의 shoot가 발생되어 양호하였다. NAA와 BA혼용처리는 0.5 mg/L NAA와 0.5 mg/L BA 혼용첨가된 배지에서 괴경. 자엽, 엽병절편 모두 shoot 분화가 양호하였으며, auxin류와 cytokinin 류 단용처리보다 NAA와 BA 혼용처리가 모들 절편에서 양호한 결과를 보였다. 뿌리발생을 유도하기 위해 NAA와 IBA 단용처리에 shoot를 배양한 결과 배양 15일경부터 0.5 mg/L IBA처리구에서 뿌리가 발생되기 시작하여 배양 30일 후에는 Pot이식이 가능할 정도로 뿌리가 발생되어 가장 양호한 결과를 보였다.

• 한국작물학회지
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• 제48권1호
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• pp.44-49
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• 2003

In vitro culture of panicle has been the method to accumulate starch and protein in immature grains by providing nutrients after florets crossed between remote genotypes artificially. Grain filling means embryo development and sucrose translocation from photosynthetic source, and starch manufacture in endosperm. The concentrations of sucrose used to culture immature rice panicle were 5, 10, 15, 20% and glutamine was 20 mM. When immature rice panicles at 5 days after flowering were cultured in distilled water with different concentrations of sucrose, glutamine 20 mM and MS medium with different concentrations of sucrose, glutamine 20 mM for 30 days the later was effective on grain filling. The optimal concentration of sucrose on grain filling in vitro culture of rice panicle was 10% and the weight of grain cultured was 10.14 mg that was corresponded to 57% of intact plant. In the method of treating plant growth regulators, the culture of immature rice panicle adding in MS medium with Kinetin, IAA, $\textrm{GA}_3$ were effective on grain filling than the culturing of immature rice panicle after submerging in solutions of Kinetin, IAA, $\textrm{GA}_3$ for 1day. When immature rice panicle was cultured in MS medium with sucrose 10% and Kinetin 46.47 $\mu$M it was effective on grain filling, respectively. The weight of grain cultured was 13.1mg that was corresponded to 75% of intact and germination rate was 51 %. When immature rice panicles were cultured in medium with different concentrations combined with Kinetin 4.65, 46.47, 464.7 $\mu\textrm{M}$, IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 30 days and in medium with IAA 5.71, 57.08, 570.80 $\mu\textrm{M}$ for 15 days after culturing in medium with Kinetin 4.65, 46.47, 464.70 $\mu\textrm{M}$ for 15 days the effect on grain filling was similar.

• Journal of Mechanical Science and Technology
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• 제17권4호
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• pp.545-561
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• 2003

We use the first-passage-time formulation by Torquato, Kim and Cule ［J. Appl. Phys., Vol. 85, pp. 1560∼1571 (1999) ］, which makes use of the first-passage region in association with the diffusion tracer's Brownian movement, and develop a new efficient Brownian motion simulation method to compute the effective conductivity of digitized composite media. By using the new method, one can remarkably enhance the speed of the Brownian walkers sampling the medium and thus reduce the computation time. In the new method, we specifically choose the first-passage regions such that they coincide with two, four, or eight digitizing units according to the dimensionality of the composite medium and the local configurations around the Brownian walkers. We first obtain explicit solutions for the relevant first-passage-time equations in two-and three-dimensions. We then apply the new method to solve the illustrative benchmark problem of estimating the effective conductivities of the checkerboard-shaped composite media. for both periodic and random configurations. Simulation results show that the new method can reduce the computation time about by an order of magnitude.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.341-345
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• 2004

An attempt has been made in this study to evaluate an applicability of Relative Effective Porosity Model (REPM) as a method for estimating saturated hydraulic conductivity (K$_{s}$) for homogeneous coarse, medium, and fine sands. The saturated hydraulic conductivities obtained from REPM are converted into average linear velocities using Darcy's Law and compared with the results from experimental tracer tests for homogeneous coarse, medium, and fine sand layer. Two types of tracer tests analyses, analytical solution using CXTFIT and moment methods, are performed to obtain reasonable linear velocity range for each layer. For the coarse and medium sands, the converted average linear velocity from REPM is in the velocity range obtained from tracer tests. However, small difference between the results from REPM and tracer tests is found for the fine sands. These results show that REPM gives reasonable estimates of saturated hydraulic conductivity.y.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.320-323
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• 2000

In the resent years, the Thin Film Transistor Liquid Crystal Display(TFT-LCD) have trend toward larger panel sizes and higher spatial and/or gray-scale resolution. In this trend, Because of its low field effect mobility, a-Si TFT is change to poly-Si TFT. In this paper, both effective-medium model of poly-Si TFTs and empirical capacitance model are applied to Pixel Design Array Simulation Tool (PDAST) and the pixel characteristics of TFT-LCD array were simulated, which were compared with the results calculated by Aim-Spice.

• Korea-Australia Rheology Journal
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• 제17권1호
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• pp.27-32
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• 2005

We determine the effective viscosity of suspensions with bidisperse particle size distribution by modifying an effective-medium theory that was proposed by Acrivos and Chang (1987) for monodisperse suspensions. The modified theory uses a simple model that captures some important effects of multi-particle hydrodynamic interactions. The modifications are described in detail in the present study. Estimations of effective viscosity by the modified theory are compared with the results of prior work for monodisperse and bidisperse suspensions. It is shown that the estimations agree very well with experimental or other calculated results up to approximately 0.45 of normalized particle volume fraction which is the ratio of volume faction to the maximum volume fraction of particles for bidisperse suspensions.

• Journal of Mechanical Science and Technology
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• 제17권10호
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• pp.1583-1596
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• 2003

A study of forced convection in a circular pipe with a partially filled porous medium was numerically investigated. The Brinkman-Forchheimer extension of the Darcy model was used to analyze the and temperature distribution in the porous medium. Our study includes two types of porous layer configurations: (1) a layer attached at the tube wall extending inward towards the centerline and (2) a layer at the centerline extending outward. The effect of several parameters, such as Darcy number, effective viscosity, effective thermal conductivity, and inertia parameter, as well as the effect of geometric parameters, were investigated.