• 한국구조물진단유지관리공학회 논문집
• /
• 제11권1호
• /
• pp.130-140
• /
• 2007

섬유시트보강 및 강판보강은 RC 구조물에 주로 사용되었으나, 이들은 조기부착파괴나 자중의 과다 등의 단점을 가지고 있어 현실적으로 적용사례가 대폭 줄어들고 있는 실정이다. 본 연구에서는 전단강도 증가를 위해 GSP(Glass fiber-Steel composite Plate)로 전단보강된 RC 보의 실험한 결과를 제시한다. GSP는 높은 강도의 유리섬유시트를 조기탈락하지 않도록 앵커링할 수 있으며, 정착시 섬유시트의 손상을 방지할 수 있도록 얇은 강판을 섬유시트 사이에 둔 보강재료이다. 기준 실험보 3개와 GSP로 전단보강된 보 60개로 전단실험을 수행하였다. 본 연구는 GSP로 전단보강된 RC보의 전단 보강효과를 평가하며, 이 실험결과 GSP로 전단보강된 RC보의 전단강도는 기준실험보에 비하여 현저히 증가하였음을 확인하였다.

• 한국식품과학회지
• /
• 제38권1호
• /
• pp.135-139
• /
• 2006

세균이 외부stress에 대한 자가저항으로 biofilm형성을 하는 것은 식품 뿐만아니라 식품기기등의 세척, 소독등의 식품안전 확보에 많은 어려움을 주게 된다. 본 연구에서는 glass wool과 mlcrotiter plate assay를 이용하여 주요 식중독 세균인 Salmonella, E. coli, B. cereus, S. aureus를 여러가지 식품보존하에서 상해와 biofilm형성 정도를 비교하였다. 이들 세균은 외부의 stress없는 조건하에서도 상해를 받지 않았고 모두 biofilm이 형성되어 glass wool에 부착되었다. Microtiter plate assay에서의 상해별 biofilm형성은 acid stress에서 10%이내의 상해를 받은 E. coli와 약 40%의 상해를 받은 S. aureus에서 높게 나타났다. $4^{\circ}C$의 cold temperature에서는 30-50% 상해를 나타낸 B. cereus와 E. coli가 높은 biofilm 형성을 보였고 cold starvation에서는 다른 stress에 비해 전체적으로 biofilm형성도가 낮은 값으로 측정되었다. 그리고 6% sodium chlorine solution에서 30-55%의 상해를 입은 Salmonella가 높은 biofilm 형성도를 보였다. 그러나 같은 종의 식중독 세균이라도 외부의 stress 대하여 다양한 정도의 biofilm을 생성하는 것으로 보인다. 따라서 식품으로부터 이들 식중독 세균을 제어하기 위해서는 대상식품의 보존환경에 따른 biofilm 형성특성을 고려해야 할 것으로 사료된다.

• 한국광학회지
• /
• 제6권2호
• /
• pp.130-134
• /
• 1995

이득 선폭이 넓고 가공이 쉬원 고출력 제이저의 증폭 이득 매질로 유리한 Nd:glass 이득 매질의 소신호 이득 계수를 측정하고 이 Nd:glass를 이용하여 제작한 cavity-dumping형 레이저의 출력 특성을 조사하였다. 소신호 이득 계수를 측정하기 위해 Nd:glass, Pockels cell, 편광분할기 등을 포함하는 공진기를 구성하였으며, 측정된 소신호 이극 계수는 전기 입력 에너지가 100J일 때 $0.088 cm_{-1}$ 공진기의 왕복 내부 손실은 56%였다. Cavity-dumping형 레이저 공진기는 곡률반경이 2m인 두개의 전반사경과 Nd:glass, Pickels cell, 편광분할기, $\lambda/4$ plate 등으로 구성되었으며 제작된 레이저의 출력 에너지는 전기 입력 에너지가 140J일 때, 최대 0.85J이었고 출력 레이저 펄스폭은 8ns였다.

• 대한기계학회논문집
• /
• 제15권6호
• /
• pp.1781-1791
• /
• 1991

본 연구에서는 천이온도하에 있는 물체의 균열의 거동을 연구하기 위하여 선 적분 형태의 J적분을 유도하고 유한요소법으로 수치계산하여 기존의 결과와 비교한다. 한편 관성항과 재료의 물성치가 J적분값에 미치는 영향을 검토한다.

• Structural Engineering and Mechanics
• /
• 제85권5호
• /
• pp.573-592
• /
• 2023

This paper presents a careful theoretical investigation into interfacial stresses in composite aluminum-slab reinforced concrete beam bonded by a prestressed hybrid carbon-glass composite material. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the aluminum beam, the slab reinforced concrete, the hybrid carbon-glass composite plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of interfacial stress distributions. It is shown that the stresses at the interface are influenced by the material and geometry parameters of the composite beam. This research is helpful for the understanding on mechanical behaviour of the interface and design of the hybrid structures.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2009년도 춘계학술대회 논문집
• /
• pp.103-106
• /
• 2009

Fracture characteristics of plate shape using shock tube for glass filled ceramics was carried out. Glass filled ceramics have been considered as a promising candidate material for the dome port cover of air breathing engine. This part of the air breathing engine has an important role separating solid and liquid fuel, and needs the frangible characteristics that the fracture of a part should not affect the internal components of combustion. The objectives of this study are to evaluate the fracture pressures for various thicknesses and diameters of shock impact area. Also fracture phenomena of separated membrane using a shock tube are observed. The experimental apparatus of shock tube consists of a driver, a driven section and a dump tank. The used material is glass filled ceramic made from Corning company. Specimens are used 3, 4.5 and 6mm thickness. Also diameters of shock wave area are chosen 70, 60 and 50 mm. It is expected that the results obtained from this study can be used in the basic data for the dome port cover design of an air breathing engine.

• Structural Engineering and Mechanics
• /
• 제74권5호
• /
• pp.671-678
• /
• 2020

In this work, the dynamic properties of a high performance concrete containing glass powder (GP) was studied. The GP is a new cementitious material obtained by recycling waste glass presenting pozzolanic activity. This eco-friendly material was incorporated in concrete mixes by replacing 20 and 30% of cement. The mechanical properties of building materials highly affect the response of the structure under dynamic actions. First, the resonant vibration frequencies were measured on concrete plate with free boundary conditions after 14, 28 and 90 curing days by using an alternative vibration monitoring technique. This technique measures the average frequencies of several excitations done at different points of the plate. This approach takes into account the heterogeneity of a material like concrete. So, the results should be more precise and reliable. For measuring the bending and torsion resonant frequencies, as well as the damping ratio. The dynamic properties of material such as dynamic elastic modulus and dynamic shear modulus were determined by modelling the plate on the finite element software ANSYS. Also, the instantaneous aroused frequency method and ultrasound method were used to determine the dynamic elastic modulus for comparison purpose, with the results obtained from vibration monitoring technique.

• Structural Engineering and Mechanics
• /
• 제65권4호
• /
• pp.369-380
• /
• 2018

In this paper, a multi-layered finite element model for laminated glass plates is introduced. A layer-wise theory is applied to the analysis of laminated glass due to the combination of stiff and soft layers; the independent layers are connected via Lagrange multipliers. The von $K{\acute{a}}rm{\acute{a}}n$ large deflection plate theory and the constant Poisson ratio for constitutive equations are assumed to capture the possible effects of geometric nonlinearity and the time/temperature-dependent response of the plastic foil. The linear viscoelastic behavior of a polymer foil is included by the generalized Maxwell model. The proposed layer-wise model was implemented into the MATLAB code and verified against detailed three-dimensional models in ADINA solver using different hexahedral finite elements. The effects of temperature, load duration, and creep/relaxation are demonstrated by examples.

• Genomics & Informatics
• /
• 제4권3호
• /
• pp.133-136
• /
• 2006

The adsorption of proteins on the surface of glass slides is essential for construction of protein chips. Previously, we prepared a nickel-coated plate by the spin-coating method for immobilization of His-tagged proteins. In order to know whether the structural factor is responsible for the immobilization of His-tagged proteins to the nickel-coated glass slide, we executed a series of experiments. First we purified a His-tagged protein after expressing the vector in E. coli BL21 (DE3). Then we obtained the unfolding curve for the His-tagged protein by using guanidine hydrochloride. Fractions unfolded were monitored by internal fluorescence spectroscopy. The ${\Delta}G_{H20}$ for unfolding was $2.27kcal/mol{/pm}0.52$. Then we tested if unfolded His-tagged proteins can be adsorbed to the nickel-coated plate, comparing with $Ni^{2+}-NTA$ (nitrilotriacetic acid) beads. Whereas unfolded His-tagged proteins were adsorbed to $Ni^{2+}-NTA$ beads, they did not bind to the nickel-coated plate. In conclusion, a structural factor is likely to be an important factor for constructing the protein chips, when His-tagged proteins will immobilize to the nickel-coated slides.

• 한국태양에너지학회 논문집
• /
• 제33권3호
• /
• pp.36-41
• /
• 2013

The reflection plate in twin-glass evacuated tube solar collector is controlled to reduce the overheat during the summer time. The sliding type and folding types are suggested and tested. The sliding type changes the plate angle and the folding type changes the opening angle of the reflection plate. By scattering the focus of the reflected radiation from the reflection plate, the temperature rise of the working fluid can be reduced. The sliding type shows the best results in overheat reduction. When solar radiation is 900 $W/m^2$, the temperature rise in one sliding type collector is reduced about $2^{\circ}C$ compared to that of the normal solar collector. When this method is applied to seven series-collectors in the field, the reduction of temperature rise during the summer time should be significant.