• Journal of Korean Society of Steel Construction
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• v.16 no.3 s.70
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• pp.325-332
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• 2004

Cross sections of steel-plate girder bridges are divided into three cross sections of non-composite, partially composite, and fully composite sections, according to their composite characteristics. The Korean provision for the partially and fully composite sections specifies general usage of the stud of shear connectors, whereas the one for the non-composite section specifies empirical usage of slab anchors. However, the actual behavior of the cross sections of steel-plate girder bridges using slab anchors is close not to the non-composite action, but to the partially composite action. Therefore analytical and experimental studies on partial composites of steel-plate girder bridges using slab anchors are performed in this study. Intial stiffness of the slab anchor is obtained by the experimental study for the first time, and the composite characteristic of simple-span and two-span continuous steel-plate girder bridges is investigated by the finite element analyses for the second time. Based on the obtained initial stiffness, the reduction effect of tensile stresses in the concrete-slab on the intermediate support of the continuous bridge is also considered herein.

• Journal of Energy Engineering
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• v.10 no.1
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• pp.40-48
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• 2001

디젤엔진에 적합한 환경 친화적 연료로 평가받고 있는 디메틸에테르(DME)를 기존의 메탄올 탈수화에 의한 간접법 대신 합성 가스로부터 직접 합성법으로 제조하였다. 합성가스에서 메탄올을 합성하는 경우에 비해 화학 평형 상의 이점 때문에 DME를 합성하는 것이 경제적이며 이는 실험 결과와 일치하였다. 기상 반응기에서 메탄올 탈수촉매의 부가에 의한 메탄올 환산 생산량은 메탄올 합성촉매에 의한 생산량에 비해 두 배 이상의 증가를 보인다. 메탄올 탈수촉매를 Cu로 개질한 효과는 없었으며, 메탄올 탈수촉매로서 순수 감마알루미나가 가장 우수한 반응성을 보였다. 반응 조건이 25$0^{\circ}C$, 30atm일 때 고려된 GHSV 범위에서 촉매 적정 혼합비는 7:3, 합성 가스의 조성비는 $H_2$/CO=1일 때 가장 좋은 선택도와 수율을 나타내었다.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.1_2
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• pp.110-123
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• 2001

본 논문에서는 자유 선택 신호 전이 그래프와 비동기 유한 상태기로 기술된 회로 명세로부터 직접 속도 독립 회로를 합성하는 시스템에 대해 기술한다. 기존의 상태 그래프 기반의 합성 시스템은 상태의 수가 지수승으로 증가할 수 있기 때문에 큰 규모의 회로에 대해서는 합성에 실패할 수 있다는 문제점을 가지고 있다. 이를 해결하기 위해 여러 직접 합성 방법들이 제안되었는데, 본 논문의 합성 시스템은 마크드 그래프 분할 방법과 임시 전이의 사용을 허용함으로써 합성할 수 있는 회로의 범위를 넓혔다. 기존의 벤치마크 회로에 대한 실험결과 본 합성 시스템은 기존의 상태 그래프 기반의 합성 시스템에 비하여 현저하게 수행 속도를 단축시킬 수 있었고 기존의 직접 합성 시스템에 비하여 보다 확장된 그리고 보다 실용적인 회로 명세를 처리할 수 있었다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1994.11a
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• pp.132-156
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• 1994

본 논문에서는 비선형 합성 함수를 이용하여 생성된 난수 계열의 특성을 분석한다. 먼저 트레이스 함수 등을 정의하고, 선형 복잡도 및 생성기 구조 분석시 요구되는 관련 이론을 도출하고, 특정 난수 계열이 주어진 경우 이계열을 생성할 수 있는 최소 길이의 LFSR을 합성할 수 있는 USR 합성 알고리듬을 제시한다. 동일한 계열을 위상 천이한 계열간의 비선형 결합으로 생성된 난수 계열과 다른 계열간의 비선형 결합으로 생성된 난수 계열에 대한 주기 및 선형 복잡도 등의 특성을 분석하고 생성기의 구조를 제시한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.2 s.72
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• pp.203-212
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• 2006

Although composite construction has many mechanical advantages over noncomposite construction, the design of noncomposite construction for skew bridges with large skew angels has been often checked because composite construction caused large stresses in the bridge deck. But there is somewhat difficulty to apply noncomposite construction in the field because of the structural problem such as the slip at the interface between the concrete deck and steel girders. In this study, the validity of the application of the composite construction to skew angles with large skew angles is investigated by analyzing effects of two interactions such as composite and noncomposite actions between the concrete deck and steel girders on the behavior of skew bridges. A series of parametric studies for the total 27 simply supported skew bridges was conducted with respect to parameters such as girder spacing, skew angle, and deck aspect ratio. The improvement of the behavior of composite skew bridges was examined by using the concept of the stiffness adjustment of bearings which I suggested in previous research. Results of analyses show that a more desirable behavior of skew bridges can be obtained from composite construction instead of noncomposite construction and the method of the stiffness adjustment of bearings results in a more rational and economical design of composite skew bridges and substructures.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.5
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• pp.593-604
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• 2007

Although composite construction has more mechanical advantages compared to noncomposite construction, the design of noncomposite construction for skew bridges with large skew angels has been often checked because composite construction may cause large stresses in the bridge deck. In this study, the analytical model considered dynamic behaviors for noncomposite skew bridges was proposed. Using the proposed analytical model, the validity of the application of noncomposite construction to skew bridges was checked. Also, the effects of interactions between the concrete deck and steel girders such as composite construction, partial composite construction, and noncomposite construction on the dynamic characteristics and dynamic behaviors of simply supported skew bridges were investigated. A series of parametric studies for the total 27 skew bridges was conducted with respect to parameters such as girder spacing, skew angle, and deck aspect ratio. Although the slip at the interfaces between the concrete deck and steel girders results in the reduction of seismic total base shear in the transverse direction due to period elongation, it causes an undesirable behavior of skew bridges by the modification in mode shapes and distributions of stiffness. Shear connectors placed by minimum requirements for partial composite action have an effect on reducing the girder stresses and deck stresses; except case of some skew bridges, the magnitude of the girder stresses and deck stresses obtained from partial composite skew bridges is similar to or slightly more than those acquired from composite skew bridges.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.195-201
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• 2006

In multicarrier code division multiple access(MC-CDMA), the total system bandwidth is divided into a number of sub-bands, where each subband may use direct-sequence(DS) spreading and each subband signal is transmitted using a subcarrier frequency. In this paper, the system performance analysis of MC-CDMA using to gain combining(EGC) and maximal ratio combining(MRC) method over frequency selective Nakagami-m fading channel is analyzed. In the proposed system, a data sequence is serial-to-parallel converted, and MC-CDMA is used on each of the parallel data streams. The data streams are spread at both the symbol fraction level and at the chip level by the transmitter. In this paper, the compare to analysis,two standard diversity combining techniques, EGC and MRC, The good performance of system using to MRC more than EGC

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1667-1676
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• 2014

Because of the different flexural rigidity between longitudinal and transverse direction, orthotropic plate theory may be suitable for describing the behavior of composite deck. The ratio of flexural rigidity between longitudinal and transverse direction affects the live load moment. Because of the ratio of flexural rigidity of concrete unfilled steel grid deck has a direct relationship with main bearing bar spacing, it is concluded that the study for the distribution factor which is effected by main bearing bar spacing and aspect ratio is needed. In this study, evaluate the live load moment of concrete unfilled steel grid deck using the AASHTO LRFD Bridge Design Specification and presents the distribution coefficient equation for concrete unfilled steel grid deck.

• Korean Journal of Environmental Agriculture
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• v.12 no.3
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• pp.230-238
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• 1993

To develop multifunctional microorganisms for effective wastewater treatment, the cell of P. aeruginosa P1 enable to accumulate lead in its cell were conjugated with the cell of P. fluorescens S1 enable to degrade efficiently synthetic detergents. The plasmids of the P. aeruginosa P1 and the P. fluorescens S1 were found in the cell of the conjugants when determined by agarose gel electrophoresis. The conjugants obtained from P. fluorescens S1 as a recipient cell and P. aeruginosa P1 as a donor cell possessed the ability to degrade synthetic detergents as well as to accumulate lead.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.90-97
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• 2000

There are various kinds of factors associated with the formation of dental plaque in oral cavity such as nutrient molecules and chemical agents. The factors influencing the formation of insoluble glucan by Streptococcus sobrinus and its replication were examined on orthodontic wires. The results were as follows: 1. Insoluble glucan was well produced in the media initially adjusted at pH 7.0 than pH 5.5 or pH 8.5 like bacterial replication. 2. The synthesis of insoluble glucan and bacterial replication were significantly increased in the media containing 2.5% yeast extract. The formation of insoluble glucan was inhibited by 10 folds in the media containing 20% of sucrose than 1.25%, but the replication of bacteria was increased by 20 folds. 3. Insoluble glucan was significantly formed at a concentration of 1.0mM of calcium chloride, 40mM of potassium chloride, 0.1mM of magnesium chloride, while the replication of bacteria was little influenced by them regardless their concentration. 4. The formation of insoluble glucan and bacterial replication were significant in the media containing 10mM of sodium bicarbonate, but both were completely inhibited at 100mM or above. The production of insoluble glucan and the bacterial replication were largely decreased at 10mM of Tris while insoluble glucan was formed in abundance at 100mM of Tris. 5. The synthesis of insoluble glucan and the bacterial replication were inhibited at 10mM or above of sodium phosphate and potassium phosphate.