• 전기학회논문지
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• 제61권12호
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• pp.1813-1819
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• 2012

This paper presents vector magnetic properties of an electrical steel sheet (ESS) employed for electric machine and iron loss analysis considering the vector magnetic properties of the ESS. The vector magnetic properties of the ESS are measured by using a two-dimensional single sheet tester and modeled by an E&S vector hysteresis model to be applied to finite element method. The finite element analysis considering the vector magnetic properties is applied to iron loss analysis of a three-phase induction motor model, and the influences of the vector magnetic properties on the iron loss distribution are verified by comparing with numerical results from a typical B-H curve model.

• 응용통계연구
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• 제22권5호
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• pp.943-960
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• 2009

본 연구는 한반도 바람자원 TMY(typical meteorological year)의 구축에 적절한 알고리즘을 제안하고, 이를 전국 77개 기상관측소에서 1998년~2008년 기간 동안 관측한 바람자료에 적용하여 TMY를 구축하였다. 제안된 알고리즘은 Filkenstein-Shafer(FS) 통계모형 하에서 정의된 다양한 통계를 사용하여 연/원별 바람자료의 설명력 측도인 TMM(typical meteorological month)점수를 구하고, TMM점수에 기준하여 TMY를 구축하는 절차이다. 알고리즘은 두 단계 계산알고리즘으로 구성되었으며, 첫 단계는 각 관측소의 바람개황 그리고 둘째 단계는 한반도의 바람개황을 대표하는 TMY가 되도록 설계하였다. 11년 바람자료와의 비교분석, 경쟁모형에 의해 구축된 TRY(typical reference year)들과의 비교, 기상요소 추가에 따른 TMY의 영향평가 등 여러 종류의 비교 및 평가를 통하여 한반도 바람자원의 개황에 대한 TMY의 대표성과 효용성을 보였다.

• 한국작물학회지
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• 제50권3호
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• pp.186-190
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• 2005

서로 다른 벼 3아종의 품종군에 대한 아밀로그램 특성을 상관 및 주성분 분석으로 품종의 다양성을 파악한바 결과를 요약하면 아래와 같다. 1. 최고점도와 강하점도에서 나타난 성적으로 보아 통일형의 temperate indica품종군이 전형적인 인디카 품종군과 신초형의 tropical japonica품종군보다 자포니카 혈연에 가까웠다. 2. temperate indica 품종군이 전형적인 인디카 품종군과 tropical japonica 품종군보다 최종점도, 응집점도 및 취반점도는 낮게 나타났다. 3. 최고점도와 최저점도는 3아종의 품종군에서 다같이 고도의 정상관을 보였고 강하점도와 취반점도는 3아종에서 다같이 고도의 부상관을 보였다. 4. 제1주성분은 호화온도, 최종점도, 응집점도 및 취반점도를 증가시키는 방향으로 그리고 최고점도 및 강하점도는 감소시키는 방향으로 작용했다. 5. 주성분치로서 평면상 도표를 그린 품종군 분류로 품질관련 아밀로그램 특성의 공통된 품종의 특성을 파악할 수 있었다.

• KSTLE International Journal
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• 제6권1호
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• pp.8-12
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• 2005

The electrorheological properties pertaining to the electrorheological (ER) bebaviour of chitin and chitosan suspensions in silicone oil were investigated. Chitosan suspension showed a typical ER response (Bingham flow behavior) upon application of an electric field, while chitin suspension acted as a Newtonian fluid. The difference in behaior results from the difference in the conductivity of the chitin and chitosan particles, even though they have a similar chemical structure. The shear stress for the chitosan suspension exhibited a linear dependence on the volume fraction of particles and a 1.18 power of the electric field. The experimental results for the chitosan suspension correlated with the conduction model for ER response.

• KSTLE International Journal
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• 제4권1호
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• pp.14-17
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• 2003

The electrical and rheological properties of a chitosan malonate suspension in silicone oil was investigated by varying the electric fields, volume fractions of particles, and shear rates, respectively, The chitosan malonate susepnsion showed a typical electrorheological (ER) response caused by the polarizability of an amide polar group and shear yield stress due to the formation of multiple chains upon application of an electric field. The shear stress fur the suspension exhibited a linear dependence on the volume fraction and an electric field power of 1.88. On the basis of the experimental results, the newly synthesized chitosan malonate suspension was found to be an anhydrous ER fluid.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.123-128
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• 2001

The Purpose of this study is to clarify the effect of the monomer ratio on properties of the polymer-modified mortars using methyl methacrylate-butyl acrylate latexes, and to obtain basic data necessary to develop appropriate latexes for cement modifiers. This paper deals with the effect of the monomer ratio on the typical properties of polymer-modified mortars with methyl methacrylate-butyl acrylate latexes. The polymer latex-modified mortars are prepared with 5, 10, IS and 20% of polymer cement ratio respectively, and properties of modified mortars such as water absorption, compressive and flexural strengths, chloride-ion penetration depth are tested. The test results indicate that the monomer ratio is very important factors to characterize the strength properties of polymer-modified mortars, but the water absorption and chloride-ion penetration depth are influenced by polymer-cement ratio rather than monomer ratios.

• 한국기계가공학회지
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• 제7권1호
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• pp.9-16
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• 2008

It is important not only to reduce the casting defects of piston but also to improvement in the mechanical properties(hardness) of piston for the air compressor. The blow hole is typical casting defects in the conventional cast of aluminium alloy(AC8A-T6) piston. Because of the heat treatment method, mechanical properties of the aluminium alloy for piston was decided on the heat treatment method and cycle. Therefore, we tested on the development of mechanical properties and on the casting defects of piston for the air compressor in accordance with the heat treatment and casting condition. After the heat treatment and casting was carried out as several times, and was compared with the imported piston. As a result of several investigations; microstructure, hardness and casting defects of piston was changed under the influence of the heat treatment and casting method. When the cooling rate was controlled and the uni-cast method used, it bas the same mechanical properties and microstructure.

• Journal of Applied Biological Chemistry
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• 제43권4호
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• pp.207-210
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• 2000

As a typical example of the screening for a microbial biocatalyst from nature, isolation of nitrilesynthesizing microorganisms, characterization of a new enzyme aldoxime dehydratase, and its function in the aldoxime-nitrile pathway are introduced. Catalytic properties of some of our enzymes were improved through a direct evolutionary approach.

• 공업화학
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• 제10권8호
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• pp.1216-1220
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• 1999

괴상 중합과 현탁 중합 및 수산화나트륨을 이용한 중화를 통하여 제조된 poly(styrene-co-sodium methacrylate) 이오노머의 가소제로 스테아린산 아연을 첨가하여 열적 성질과 유변학적 성질에 미치는 영향을 조사하였다. 이오노머 중 스테아린산 아연은 이온기 함량에 따라 부분적으로 결정화가 억제됨이 관찰되었다. 이오노머 중 이온기들은 스테아린산 아연을 용해시키고 결정화를 억제하는 것으로 판단되었으며, 이온기 1몰이 0.4~0.6몰의 스테아린산 아연을 용해시키는 것으로 추정할 수 있었다. 용해된 형태의 스테아린산 아연만을 포함한 이오노머는 Cox-Merz 플롯에서 전형적인 균일계의 유변학적 거동을 보였다. 그러나 용해된 스테아린산 아연뿐 아니라 결정성 스테아린산 아연을 포함한 이오노머들은 Cox-Merz 플롯에서 불균일계의유변학적 거동을 보였다.

• 한국물환경학회지
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• 제23권4호
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• pp.482-489
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• 2007

Fluorescence properties and carbohydrate content were investigated using ultrafiltrated size fractions of dissolved organic matters (DOM) originated from different sources. The materials included a treated sewage, an algal organic matter, and a soil leachate, all of which are major constituents of dissolved organic matter in a typical urban river. Four different size fractions were separated from the three sources of each DOM. The size distribution demonstrated that a higher molecular weight fraction was more present in soil leachate compared to two other source DOMs. A higher content of carbohydrates was observed in the following order - algal DOM > treated sewage > soil leachate. A wide range of specific UV absorbance was observed from size fractions of a single source DOM, indicating that aromatic carbon structures are heterogeneously distributed within one source of DOM. The structural heterogeneity was the most pronounced for the soil leachate. The fluorescence index ($F_{450}/F_{500}$) of the treated sewage was similar to that (2.0) typically obtained from autochthonous DOM, suggesting that the treated sewage exhibited autochthonous organic matter-like properties. No protein-like fluorescence intensities were observed for all of the soil leachate size fractions whereas they were observed with two other source DOMs. Based upon the fluorescence peak ratios from fluorescence excitation-emission matrix (EEM), two discrimination indices could be suggested to distinguish three different source DOMs. It is expected that the suggested discrimination indices will be useful to predict the sources of DOM in a typical urban river affected by treated sewage.