• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.381-388
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• 2006

A porous medium is composed of solids, fluids, and gas which have different physical and chemical properties. In addition, these constituents have a relative velocity between each other. So far, in order to analyze porous media using finite element method, Lagrangian or Eulerian method has been used. However, the numerical analyses for porous media have a defect that the methods do not describe the movements of constituents. In this paper, numerical analysis for unsaturated porous media was performed in frame of ALE method which has advantages of Lagrangian and Eulerian. Namely, the Lagrangian description was used in solid phase, and the Eulerian description was used in fluid or gas phase in a porous medium Then the relationship between each other was controlled by the convective term in ALE method. Finally, the numerical results of ALE were compared with tile results of Lagrangian analysis.

• 생약학회지
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• 제25권1호
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• pp.28-30
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• 1994

The rate of growth and production of bioactive substances from Rehmannia glutinosa Liboschitz (Scrophulariaceae) were studied with the variation on the constituents of the culture media. The best growth was observed from MS basal medium containing 3.0 ppm NAA and 2.0 ppm kinetin. Carbohydrates (fructose, glucose and sucrose), phytosterols(${\beta}-sitosterol$, campesterol and stigmasterol) and carotenoid like substances were identified by GC-MS and TLC from the callus mass. However, catalpol was not detected from both solid and cell suspension cultures containing geraniol. Callus cultured Rehmannia glutinosa in the MS basal medium containing 0.1 ppm NAA and 0.1 ppm kinetin become differentiated to root.

• 한국세라믹학회지
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• 제36권11호
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• pp.1189-1197
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• 1999

Low-density silica gel monolith was synthesized at ambient pressure by surface modification with TMCS and sub-sequent heat treatment. The mechanical thermal and optical properties of gel were studied. Compressive strength and modulus of compression of 350$^{\circ}C$-heated gel with the density of 0.24g/cm3 were 250kPa and 0.2MPa respectively. The thermal conductivity of silica gels synthesized at ambient pressure exhibited 0.02 W/m$.$K for the density of 0.24g/cm3 which is similar to that of the gel via supercritical drying and their main thermal transfer mechanism is considered to be solid and radiation conduction at room temperature. Ambient-dried silica gels were transparent blue showing about 60% of transmittance in the wavelength of 1500-2100nm and typical absorption bands of existing bonds under heat treatment at 350$^{\circ}C$. Medium scale monolity(${\Phi}$=50mm) at ambient pressure could be successfully prepared through total 5-month process period.

• Journal of Welding and Joining
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• 제32권1호
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• pp.34-39
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• 2014

There are so many difficulties of melt bonding mainly applied for hull construction of a aluminum alloy small boat. For resolving this problem, Friction stir welding(FSW) in non-melting solid state welding Process generally is applied in the transport industry. This paper is studied the joining strength characteristics and macrostructure according to dissimilar aluminium 5000/6000 alloy joining for a small boat applied for this FSW technology. It is reported that difference of joining strength in accordance with the direction of rotation in case of friction stir welding between dissimilar metals(Al/Cu, Al/Fe) is also highly large. In this study, Test is carried out by making the specimen according to the direction of rotation of dissimilar aluminium alloy joining.

• 한국자원식물학회지
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• 제11권1호
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• pp.15-21
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• 1998

This study was carried out to determine the effects of plant growth regulators on cell culture and organogenesis from Sicyos angulatus L. using explants of leaves, stems and cotyledons. Optimal callus induction for S. angulatus was obtained on MS medium with 0.1mg/$\ell$ BA and 2.0mg/$\ell$ 2,4 -D from cotyledons, 0.1mg/$\ell$ BA and 5.0mg/$\ell$ NAA from leaves explants, Optimal media for subculture and growth of S. angulatus callus were 1/2 MS medium with 0.1mg/$\ell$ BA and 1.0mg/$\ell$ 2,4 -D for solid culture, and 0.1mg/$\ell$ 2,4-D for suspension culture. Many adventitious roots with some shoots were formed were formed from leaf and cotyledon explants of S. angulatus during callus induction with optimal combinations of plants growth regulators.

• Journal of Microbiology
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• 제40권2호
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• pp.173-177
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• 2002

In order to identify Yawowia lipolytica genes induced by serum, cDNA representational difference analysis was performed using a PCR-select CDNA subtraction method. One of the genes cloned from the subtraction was a gene (YIMBFl) homologous to Saccharomyces cerevisiae MBF1 encoding the coactivator multiprotein bridging factor 1. Disruption of YIMBFl revealed that the gene was net essential for viability, and the Ylmbf△ strain did not show any distinct phenotypic change on solid serum medium. In liquid medium, however. a difference was found in the ability to maintain hyphae induced by serum. This result suggests that the YIMbf1 protein may mediate transcriptional activation of certain genes involved in the hypha fonmation of Y. lipolytica.

• Steel and Composite Structures
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• 제34권2호
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• pp.309-319
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• 2020

The objective is to study the deformation in a homogeneous isotropic modified couple stress thermoelastic medium with mass diffusion and with two temperatures due to a thermal source and mechanical force. Laplace and Fourier transform techniques are applied to obtain the solutions of the governing equations. The displacements, stress components, conductive temperature, mass concentration and couple stress are obtained in the transformed domain. Numerical inversion technique has been used to obtain the solutions in the physical domain. Isothermal boundary and insulated boundaryconditions are used to investigate the problem. Some special cases of interest are also deduced.

• Coupled systems mechanics
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• 제10권2호
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• pp.143-159
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• 2021

The theory of generalized thermo-magneto-electroelasticity is employed to obtain the plane wave solutions in an unbounded, homogeneous and transversely isotropic medium. Reflection phenomena of plane waves is considered at a stress free and thermally insulated surface. For incidence of a plane wave, the expressions of reflection coefficients and energy ratios for reflected waves are derived. To explore the characteristics of reflection coefficients and energy ratios, a quantitative example is set up. The half-space of the thermo-magneto-electroelastic medium is assumed to be made out of lithium niobate. The dependence of reflection coefficients and energy ratios on the angle of incidence is illustrated graphically for different values of electric, magnetic and thermal parameters.

• 유통과학연구
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• 제13권7호
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• pp.53-61
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• 2015

Purpose - This research analyzes overseas expansion support systems for small- and medium-sized enterprises in Germany and Japan. Germany and Japan have developed overseas expansion support policies for such enterprises. The study then explores the implications for Korea and its local governments. Research design, data, and methodology - We did a comparative analysis of Japan and Germany and their support for overseas expansion of small and medium companies. Data were mainly collected from the Ministry of Economy, Trade and Industry (Japan) and the Germany Trade and Invest (Germany) agency through statistics and literature surveys, and analysis studies. Results - First, human resources cultivation and funding support policies, which both Germany and Japan use as part of small- and medium-sized enterprise policies, should be modified to Korean circumstances and to reflect its own small- and medium-sized enterprise support needs. Second, both the German policies that support overseas expansion of small- and medium-sized enterprises and those of Japan's include the philosophy and methods that put an emphasis on these enterprises, despite the fact that there are big differences in the overseas policies in these two countries. Third, German and Japanese governments are embracing the idea that small- and medium-sized enterprises are key to their national economies and implementing policies based on the ratio occupied by these enterprises in the domestic consumption or GDP. In other words, Germany and Japan consider small- and medium-sized enterprises as central to their nation's industry, and assess them as economic industry that should definitely exist for the continued survival of big businesses, and not just as merely supplemental to big business. Fourth, whereas Germany emphasizes support to product exhibition in its overseas expansion support policies, Japan is providing integrated support containing foreign direct investment to small- and medium-sized enterprises. Fifth, there are differences in the overseas expansion support in Germany and Japan in terms of their support to big business. Whereas Germany considers support to big business unnecessary, Japan is implementing active support policies to areas corresponding to big business. Korea will have to benchmark the policies of Germany and Japan, and decide whether or not to give full support to small- and medium-sized enterprises, while excluding areas supporting big business. Conclusions - Based on this analysis of German and Japanese overseas expansion support policies, we need to choose the policies that will engender a solid outcome and derive modified policies for the circumstances of Korea. Additionally, we can use the comparison of the overseas support policies of Japan and Germany to choose small- and medium-sized enterprise overseas expansion support policies for Korea. However, we cannot provide specific overseas support policies by industry. This point will be referenced as a limitation of this study. In future research, we expect that some researchers will take an empirical approach to exploring Korean overseas expansion support through collecting cases of overseas support policies and interviewing policy authorities.

• 유기물자원화
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• 제8권2호
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• pp.60-70
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• 2000

현재 국내에서 처리에 어려움을 겪고 있으며 사회적으로 문제가 되고 있는 양돈 분뇨의 처리중 생물학적 처리를 위한 전처리 공정의 일환으로 비육돈 슬러리 돈사에서 발생하는 분뇨를 대상으로 고액분리에 관한 연구를 수행하였다. 최적의 고액 분리를 위하여 적정 응집제 선정 및 첨가량을 도출하였으며, 현장 규모의 고액 분리 장치를 통하여 규모별 최적 고액 분리 공정을 도출하였다. 이 결과 탈수성 개량을 위한 적정 응집제로는 Polyarcylamide 계열의 양이온 고분자 응집제인 E-851이 적합하였으며, 단위 고형물당 0.24~0.6%가 요구되었다. 본 연구에서 검토된 공정으로는 Mesh Screen, Drum Screen, Cyclone Drum Filter, Screw Press, 고속 Screw Decanter, 저속 Screw Decanter 및 DAF 공정을 조합하여 검토하였다. 그 결과 최적 공정으로는 중 소규모의 1차 고액 분리 공정으로는 Screw Press(응집제 첨가)와 대규모 및 공공처리장 규모에서는 저속 Screw Decanter(응집제 첨가)가 적정 공정으로 도출되었으며 2차 처리 공정으로는 가압부상조가 가장 안정적인 것으로 나타났다. 한편 고액 분리 유무에 따라 수분조절제 및 유기물 부하량 감소는 각각 94.8, 84.7%로 나타났으며 슬러리 양돈분뇨의 정화방안으로는 고액분리가 반드시 필요한 것으로 나타났다.