• 콘크리트학회지
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• 제7권3호
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• pp.149-155
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• 1995

무세골재 콘크리트에 석분을 혼입하므로써 얻을 수 있는 강도 증가효과를 조사하기 위하여 실험을 통한 연구를 수행하였다. 시멘트-골재의 비 1 : 6, 1 : 8 그리고 1 : 10 과 30~56% 사이의 여러 물 -시멘트 비를 배합설계시에 선정하였다. 작업하기 적당한 콘크리트를 얻기 위하여 필요에 따라 고유동화제를 시멘트중량의 1.5%사용하였으며, 석분을 혼입한무세골재 콘크리트의 경우 시멘트와 같은 중량의 석분을 혼입하였다. 여러 배합설계에 대한 압축강도와 인장강도 시험 결과를 비교분석하였다. 시험결과는 무세골재 콘크리트에 비하여 압축강도는 약 38%, 인장강도는 약 17%~72% 증가시킬 수 있음을 보여주고 있다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.201-208
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• 2000

The reduction of NO by hydrocarbons was investigated over Cu/Al$_2$O$_3$catalysts using a stainless steel flow reactor under highly oxidising diesel exhaust conditions(up to 15%). Three different Cu loadings(1,5 and 10wt.%) on an $Al_2$O$_3$support were prepared and characterized using spectroscopic techniques. The catalytic activity tests show that different Cu loadings as well as temperature, oxygen, and hydrocarbon concentration levels significantly influence the NO reduction. Increasing Cu loadings up to 5 and 10wt.% decreases the catalytic activities for NO reduction due to the formation of a bulk crystalline CuO phase, as observed from XRD and SEM images. In particular, the visualization of the copper dispersion on the surface using the SEM-BEI technique provides information on the extent of copper saturation, particle size, and the effects on NO reduction. However, the lower Cu loading(1 wt.%) increases the catalytic activity with a temperature window of 720-810K, thereby favoring the formation of well dispersed isolated Cu species, e.g. Cu(sup)2+ ions, which is related to selective NO reduction. The effects of other reaction parameters, such as oxygen, the hydrocarbon level and type, and byproduct emissions are further discussed.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1191-1194
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• 2014

Imaging Differential Optical Absorption Spectroscopy (Imaging-DOAS) has been utilized in recent years to provide slant column density (SCD) distributions of several trace gas species in the plume. The present study introduces a new method using Imaging-DOAS data to determine two-dimensional plume structure from the plume emissions of power plant in conditions of negligible aerosol effects on radiative transfer within the plume. We demonstrates for the first time that two-dimensional distributions of sulfur dioxide ($SO_2$) and nitrogen dioxide ($NO_2$) in power plant emissions can be determined simultaneously in terms of SCD distribution. The $SO_2$ SCD values generally decreased with increasing distance from the stack and with distance from the center of the plume. Meanwhile, high $NO_2$ SCD was observed at locations several hundred meters away from the first stack due to the ratio change of NO to $NO_2$ in NOx concentration, attributed to the NO oxidation by $O_3$. The results of this study show the capability of the Imaging-DOAS technique as a tool to estimate plume dimensions in power plant emissions.

• ETRI Journal
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• 제31권2호
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• pp.111-120
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• 2009

Network-on-chip (NoC) architecture provides a highper-formance communication infrastructure for system-on-chip designs. Circuit-switched networks guarantee transmission latency and throughput; hence, they are suitable for NoC architecture with real-time traffic. In this paper, we propose an efficient integrated scheme which automatically maps application tasks onto NoC tiles, establishes communication circuits, and allocates a proper bandwidth for each circuit. Simulation results show that the average waiting times of packets in a switch in $6{\times}6$6, $8{\times}8$, and $10{\times}10$ mesh NoC networks are 0.59, 0.62, and 0.61, respectively. The latency of circuits is significantly decreased. Furthermore, the buffer of a switch in NoC only needs to accommodate the data of one time slot. The cost of the switch in the circuit-switched network can be reduced using our scheme. Our design provides an effective solution for a critical step in NoC design.

• Journal of Oral Medicine and Pain
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• 제25권2호
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• pp.215-221
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• 2000

A 69-year-old male pateint was admitted for discomfort on right temporomandibular joint during opening, closing and chewing that started few months ago. The patient had no special medical history except for lung tuberculosis approximately 30 years ago and nothing specific appeared on a physical exam taken 2 months ago. Clinical tests show that mouth opening of 53mm which was normal and no joint sound, deviation, pain during opening. But tenderness to palpation on Rt masseter muscle and pain existed on Rt temporomandibular joint during loading test on the right joint. No pain existed during resistance test and protrusion and range of lateral movement was normal. Rt temporomandibular joint was not swollen and no palpable mass was observed. No previous trauma history to the face existed. On X-ray calcific material existed in the joint cavity and on CT image, approximately 2mm sized calcific material appeared on the Rt temporomandibular joint but no change in bone appeared on the condyle nor the temporal bone. The patient was diagnosed as loose body, and the symptoms were relived after 2 physical therapies and is under regular check ups. The purpose of this case is to review disease that cause loose bodies.

• Journal of applied mathematics & informatics
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• 제30권3_4호
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• pp.381-393
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• 2012

In this paper, we show two ways of the time reparametrization of piecewise Pythagorean-hodograph $C^1$ Hermite interpolants. One is the time reparametrization with no shape change, and the other is that with shape change. We show that the first reparametrization does not depend on the boundary data and that it is uniquely determined by the size of parameter domain, up to the general cases. We empirically show that the second parametrization can cause the change of the shape of interpolant.

• 대한수학회지
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• 제52권1호
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• pp.67-80
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• 2015

For a pomonoid S, let us denote Pos-S the category of S-posets and S-poset maps. In this paper, we consider the slice category Pos-S/B for an S-poset B, and study some categorical ingredients. We first show that there is no non-trivial injective object in Pos-S/B. Then we investigate injective objects with respect to the class of regular monomorphisms in this category and show that Pos-S/B has enough regular injective objects. We also prove that regular injective objects are retracts of exponentiable objects in this category. One of the main aims of the paper is to draw attention to characterizing injectivity in the category Pos-S/B under a particular case where B has trivial action. Among other things, we also prove that the necessary condition for a map (an object) here to be regular injective is being convex and present an example to show that the converse is not true, in general.

• 한국환경과학회지
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• 제5권6호
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• pp.801-812
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• 1996

We investigated concentrations of heavy metals(Cr, Cd, Zn, Fe, Pb, Cu, and Mnl and correlations between concentrations of heavy metals in the sediment, soil, weeds, and vegetables on the lower Nakdong river. Concentrations of heavy metals on the lower Milyang river was generally lower than those of other sampling area. In the soil, concentration of Pb is generally larger than that of other heavy metals. Generally, concentrations of heavy metals in the sediment show decreasing tendency 8s the sampling area moves toward downstream of the river, but those of in the soil and weeds show increasing tendency. There is no significant correlation between concentration of heavy metals in the soil-sediment, soil-vegetables, sediment-weeds, or vegetables-weeds. Only concentrations of Pb in the vegetables and those of in the weeds show very high correlation.

• 한국항공운항학회지
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• 제15권3호
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• pp.70-76
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• 2007

The benefits for using reduced takeoff thrust are many, ranging from lower maintenance and operating costs to improved engine and dispatch reliabilities. Some pilots, however, are apprehensive about using reduced thrust. They are particularly reluctant to use the maximum permissible level of reduced thrust. Two common arguments are (1)If reduced thrust is used, then the airplane will not be able to clear the obstacles if an engine fails during takeoff, and (2)If the maximum allowable assumed temperature is used, then there will be no stopping margin left if the takeoff is aborted. There is the notion that using reduced thrust sacrifices safety. The intent of this discussion is to: (1)Show that reduced thrust performance meets all regulatory requirements (2)Show that the Assumed Temperature method includes inherent extra performance margins (3)Show how to maximize performance margins while maximizing thrust reduction.

• 정보보호학회논문지
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• 제30권5호
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• pp.795-803
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• 2020

본 논문에서는 SP 구조의 F-함수를 가진 4-브랜치 GFN-2 구조에 대한 기지키 구별 공격(Known-Key Distinguishing Attack) 및 부분 충돌 공격(Partial-Collision Attack)을 연구한다. 첫 번째로, 이 구조에 대해 기지키 구별 공격이 15 라운드까지 가능함이 밝혀진다. 두 번째로, 마지막 라운드에 셔플 연산이 있는 경우, 부분 충돌 공격이 14 라운드까지 가능함이 밝혀진다. 마지막으로, 마지막 라운드에 셔플 연산이 없는 경우, 부분 충돌 공격이 15 라운드까지 가능함이 밝혀진다.