• 대한화학회지
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• 제52권5호
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• pp.523-529
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• 2008

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1129-1132
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• 2005

We report state-of-the-art phosphorescent organic light emitting diode lifetime and efficiency performances for a range of emission colors. Lifetimes in excess of 100,000hrs have been demonstrated at display luminance levels for saturated red emission. External quantum efficiencies close to the theoretical maximum (e.g. 23% without enhanced optical output coupling) are also demonstrated for devices with lifetimes in excess of 15,000hrs at a display level luminance for both orange red and green.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2003년도 정기총회 및 추계학술대회
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• pp.115-119
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• 2003

The green space become more important in the city. It is shown as the urban neighborhood park. But the current problem of urban neighborhood parks planning in Ulsan is uniform without reflecting area's characteristic. The Purpose of this study is to propose the planning methods of urban neighborhood parks by surveying characteristic of each urban neighborhood parks in Ulsan actual states and use behaviors.

• 대한수학회지
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• 제37권4호
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• pp.579-592
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• 2000

We study the variational principle for quantum unbounded spin systems interacting via superstable and regular interactions. We show that the (weak) KMS state constructed via the thermodynamic limit of finite volume Green's functions satisfies the Gibbs variational equality.

• Journal of the Korean Statistical Society
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• 제21권1호
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• pp.14-26
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• 1992

In this paper, asymptotic expansions of the distribution of the likelihood ratio statistic for testing multisample sphericity have been derived in the null and nonnull cases when the alternatives are close to the null hypothesis. These expansions are obtained in the form of series of data distributions.

• Journal of the Korean Statistical Society
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• 제10권
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• pp.140-144
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• 1981

This paper approximates to a kernel density estimate by a truncated series of expansion involving Hermite polynomials, since this could ease the computing burden involved in the kernel-based density estimation. However, this truncated series may give a multimodal estimate when we are estiamting unimodal density. In this paper we will show a way to insure the truncated series to be positive and unimodal so that the approximation to a kernel density estimator would be maeningful.

• Journal of Ginseng Research
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• 제47권1호
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• pp.167-167
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• 2023

• 한국지반환경공학회 논문집
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• 제16권12호
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• pp.45-52
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• 2015

최근 산림 훼손지를 원래 상태로 되돌리기 위한 생태복원에 대한 관심이 높아지면서 인공 비탈면을 보강하면서 친환경적인 녹화가 될 수 있는 연구가 진행되고 있으며, 이러한 생태복원을 목표로 식생생육의 기반이 되는 인공토양의 조성과 관련된 많은 기술들이 개발되고 있는 추세이다. 본 연구에서는 하수오니, 톱밥, 제지슬러지, 화강풍화토가 포함되어 사용되고 있는 녹생토와 친환경적인 토양안정재를 활용하여 연구수행을 하였다. 토양안정재와 혼합된 녹생토를 이용해 기본물성실험을 통해 녹생토의 기본적인 특성을 분석하였으며, 친환경적인 토양안정재를 일정비율로 녹생토와 혼합하여 각각의 비율에 따른 전단강도실험을 수행하여 최대전단강도를 분석하고 이에 따른 점착력과 내부마찰각을 산정하였다. 그리고 녹생토와 토양안정재의 혼합비율을 전단강도실험과 동일한 조건으로 비탈면의 기울기를 적용하여 토양안정재의 혼합비율에 대한 침식률과 발아율을 분석하여 주변 환경적 요인에 대처 가능한 토양안정재의 경제적인 혼합비율을 고찰하고자 한다. 실험결과 양생기간과 안정재의 혼합률에 따라 최대 51%까지 전단강도가 증가하였으며, 실험결과를 바탕으로 내부마찰각과 점착력이 모두 상승한 점을 확인하여 안정재가 녹생토의 전단성능 과침식저항 향상에 기여하고 있음을 확인하였다.

• 반도체디스플레이기술학회지
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• 제6권4호
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• pp.29-32
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• 2007

Zinc gallate, $ZnGa_2O_4:Mn^{2+}$ co-doped with different concentrations of $Mg^{2+}$ (0.001- 0.5 mol%) was prepared by solid state synthesis method. These compositions were investigated for their photoluminescence and cathodoluminescence properties. The optimized composition $Zn_{0.990}Mg_{0.005}Ga_2O_4:Mn_{0.005}$ shows higher luminescence intensity compared to the parent phosphor. The intense green emission peak was found at 504 nm. The $Mg^{2+}$ doping does not affect much the decay time. It remains <10 ms for these compositions which make them potential candidate for application in TV screens.

• Environmental Engineering Research
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• 제16권1호
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• pp.29-34
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• 2011

The electric charge on a membrane was investigated by analyzing the experimental rejection of various monovalent and divalent ionic solutes. The characteristics of the separation of ionic solutes using various nanofiltration membranes were obtained from an experimental nanofiltration set-up, with a surface area of $40cm^2$ under the operational pressures between 0.25-0.3 MPa. The state of the membrane electric charge was observed using separation coefficients, i.e., the permeation ratio of monovalent to divalent ions. To confirm the state of the membrane charge observed via the separation coefficient, a calculation using the extended Nernst-Planck equation, coupled with the Donnan equilibrium, assuming different electric charge states of the membrane, was compared with the experimental rejection of ionic solutes. The examination of the characteristics of separation using three types of nanofiltration membranes showed that one of the membranes carried a negative/positive double charge density inside, while other two membranes carried either a positive or negative charge density.