We present the rectifying and nitrogen monoxide (NO) gas sensing properties of an oxide semiconductor heterostructure composed of n-type zinc oxide (ZnO) and p-type copper oxide thin layers. A CuO thin layer was first formed on an indium-tin-oxide-coated glass substrate by sol-gel spin coating method using copper acetate monohydrate and diethanolamine as precursors; then, to form a p-n oxide heterostructure, a ZnO thin layer was spin-coated on the CuO layer using copper zinc dihydrate and diethanolamine. The crystalline structures and microstructures of the heterojunction materials were examined using X-ray diffraction and scanning electron microscopy. The observed current-voltage characteristics of the p-n oxide heterostructure showed a non-linear diode-like rectifying behavior at various temperatures ranging from room temperature to 200 oC. When the spin-coated ZnO/CuO heterojunction was exposed to the acceptor gas NO in dry air, a significant increase in the forward diode current of the p-n junction was observed. It was found that the NO gas response of the ZnO/CuO heterostructure exhibited a maximum value at an operating temperature as low as 100 oC and increased gradually with increasing of the NO gas concentration up to 30 ppm. The experimental results indicate that the spin-coated ZnO/CuO heterojunction structure has significant potential applications for gas sensors and other oxide electronics.

In this study, the seismic performance of connections between filled composite beam (CG beams) and forming angle composite (FAC) column was experimentally evaluated. First, the bending tests were conducted on two CG beams and the axial tests were conducted on two FAC columns. Then, based on these preliminary test results, the cyclic loading test were performed on two interior connections between CG beam and FAC column. The main difference of two specimens is the plate shape of the CG beam. The test results showed that both specimens achieved the maximum story drift capacity over 0.04 radian which is required for special moment frame.

Nowadays, the study of CFRP reinforced with carbon fiber is focused on improving the the mechanical property. The study on the fracture data of CFRP are not properly made out than that of the general mechanical joint. In this study, the fracture property of mode 1 at the same condition of tensile experiment is investigated by applying the layer angle to laminated CFRP with the thickness of 15 mm. When the reaction forces until dropping out the bonded surface are compared with the cases of the layer angles of 0°, 45° and 60°, the reaction force is shown to be most and the elapsed time until dropping out the bonded surface is longest at that of 45°. The deformation energy is also shown to have the highest value by dropping out the adhesive interface. As the basis of the analysis result of this study, the most safety with fracture resistance is shown in the case of 45°. the bonded structure applying the appropriate layer angle is thought to have the structural safety.

This study has assessed mechanical bonding strength of lead-free solder joint. Assessment methods was performing long-term reliability test about thermal shock, thermal life and high temperature & high humidity. Based on the results of analyzing mean values that was obtained from repetion of 5 times according to each conditions, reduction of mechanical bonding strength of each tests was confirmed. When it comes to HB chip, the order of high deviation rate was shown thermal shock, high temperature & humidity and thermal life. And the higher deviation rate of R0 is high temperature & humidity, thermal life and thermal shock. The order of high deviation rate of C1 chip is high temperature & humidity, thermal shock and thermal life. Related to this result of experiment, the most stable error range of mechanical bonding strength is established. From now on optimized quantity of solder and shape of solder-joint is needed by establishing a test method which can make error range of mechanical bonding strength minimize.

To overcome the weakness of spread foundation in large space structure, the research of precast pile for replace spread foundation have been conducted. The new type of joint between PHC pile and steel column is named HAT Joint(Hollow hAlf-sphere cast-sTeel Joint). It connected PHC Pile by bolt that verification of bolt connection should be accomplished. In this paper, pull-out test and flexural performance for HAT Joint to verifying the bolt connection is explained. As a result, the pull-out and flexural capacities of bolt were checked to use in real structure. Furthermore, the equation of pull-out strength was proposed.

CFRP has the high strength and low weight. But it tends to be frail if it is applied with the mechanical bonding method using weld, rivet or bolt. So, the chemical bonding method using the special adhesive has been utilized. By applying the bonding method with the adhesive, this paper investigates the mechanical property of DCB specimen bonded with the type of mode 2 through the simulation analysis. Four kinds of specimen thicknesses are 25mm, 35mm, 45mm and 55mm in this study. The mechanical behaviors of specimens due to the forced displacements are investigated as the distributions of equivalent stresses. The reaction force becomes higher as the specimen thickness is increased. The result of this study about the fracture property of adhesive joint is thought to be contributed to the safe design of structure with CFRP.

This study investigates the mechanical behavior at the compression of bonded aluminum foam. Four kinds of specimen thicknesses are 25, 50, 75 and 100mm. These aluminum foams are compressed with the speed of 5mm/min. The reaction forces in cases of 25, 50, 75 and 100mm are 2510, 5080, 7700 and 10400N respectively. The equivalent stresses are 0.96, 1.00, 1.02 and 1.03MPa respectively. These analysis results are verified by comparing with the experimental results. The results of this study can be contributed to the safe design of structure.

In the moment frame subjected to earthquake loads, beam-column joint is structurally important for ductile behavior of a system. ACI Committee 352 proposed guidelines for designing beam-column joint details. The guidelines, however, need to be updated because of the lack of data regarding several factors that may improve the performance of joints. The purpose of this study is to investigate the seismic performance of reinforced concrete exterior joints with high-strength materials and unbonded tendons. Three specimens with different joint shear demand-to-strength ratios were constructed and tested, where headed bars were used to anchor the beam bars into the joint. All specimens showed satisfactory seismic behavior including moment strength of 1.3 times the nominal moment, ductile performance (ductility factor = at least 2.4), and sufficiently large dissipated energy.

건물외피 발생하는 열교현상은 건물의 단열성능 및 외피의 내구성에 영향을 미치며, 국내의 일반적인 주거형식인 공동주택의 발코니에 있어서 이러한 열교현상은 중요하게 고려되고 있다. 이와 같이 내·외부 발코니 슬래브 사이에서 발생하는 열교현상을 최소화하기 위한 목적으로 열교차단장치가 개발되었으며 다수의 건설현장에서 적용되고 있다. 철근콘크리트 슬래브 벽-슬래브 접합부에 열교차단장치를 적용함으로써 건물의 단열성능을 향상될 수 있으나 풍하중과 같은 양방향의 하중에 의해 열교차단장치 삽입부위가 적합한 구조성능을 확보하고 있는지에 대한 검증이 요구된다. 따라서 본 연구에서는 철근콘크리트 슬래브에 적용된 열교차단장치의 구조성능을 확인하기 위해 변위제어 방식으로 30 싸이클의 반복하중을 가력하였다. 열교차단장치가 삽입된 접합부는 요구되는 구조성능을 확보하며, 최대 모멘트강도, 에너지소산능력, 연성비가 기존의 철근콘크리트 슬래브와 비교하여 향상되는 것으로 나타났다.

This paper presents a foundation pile to steel column connection that can resist large magnitude of moment and that can be easy installed. The developed joint has spherical shape and it is given the name HAT joint to mean Hallow half-sphere steel joint. Four types of HAT joints are developed. Namely, H-type, T-type, P-type and K-type. In this paper I will talk about the performance assessment of T-type(Tube Column) and P-type(Pile Column) of HAT joints with finite element analysis and experiment on a full scale model is presented.

As the property of the aluminum foam with porosity, the effect of impact is distributed through the distortion of each lattice like honeycomb at impact. So, this porous aluminum foam is widely used at the crash box or the impact absorber guard rail to prevent the damage. In addition, there is a property of low weight by the chemical bonding using the adhesive. As this study investigates the distortion property of the aluminum foam bonded with adhesive, the fracture property and the stress distribution of the bonded interface are examined. The specimen thicknesses are 25, 35, 45, 55 and 65 mm. And the torsional moments corresponding to 100, 200 and 300 J are applied at one side of bonded aluminum foam. The mechanical behaviors at the bonded interface and the fixed part are also investigated. It can be seen that the minimum specimen thickness must become 55 mm and over in order to maintain the bonding force due to the applied impact energy. The analysis result of this study at the bonded interface effected on impact can be effectively applied into the safe design of the structure with the bonded aluminum foam.

To research the characteristics of ITO film depending on a polarity of SiOC, specimens of ITO/SiOC/glass with metal-insulator-substrates (MIS) were prepared using a sputtering system. SiOC film with 17 sccm of oxygen flow rate became a non-polarity with low surface energy. The PL spectra of the ITO films deposited with various argon flow rates on SiOC film as non-polarity were found to lead to similar formations. However, the PL spectra of ITO deposited with various argon flow rates on SiOC with polarity were seen to have various features owing to the chemical reaction between ITO and the polar sites of SiOC. Most ITO/SiOC films non-linearly showed the Schottky contacts and current increased. But the ITO/SiOC film with a low current demonstrated an Ohmic contact.

In this paper, Nonlinear Static Pushover analysis method(NSP) is proposed which apply to RC buildings reinforced by external retrofit fornseismic performance. Based on previous analysis and research, NSP is more developed by connection nonlinearity according to shearnresistance mechanism such as dowel and adhesive resistance as major shear resistance elements. According to the proposed method,nstructural analysis for example buildings was carried out to evaluate seismic performance of buildings. And, it was confirmed thatndepending on shear strain and characteristics of joint resistant of external retrofitting are different from internal retrofitting. Furthermore,nthe strength reduction coefficient of the anchor needs to be considered at the joint design.

In this study, the cold rolled DP590 FSW joints were obtained by the position control type of the FSW machine and examined. The FSW weldability was investigated using the Si3N4 tool specially made by Cold Isostatic Press (CIP). Defect-free joints were formed at 180-300 mm/min at 800 rpm. However, a groove-like defect was observed along the joint line of the advancing side due to the insufficient material flow. In addition, the life of the Si3N4 tool was compared to that of the polycrystalline cubic boron nitride (PCBN) tool for the durability. The SI3N4 tool that was broken in which tool reached a length of 5 m and around half of the performance level of the PCBN tool.

In Part I, we disccussed of joint between PHC pile and steel column in foundation of large space structures, one prototype of a joint of PHC pile to steel pipe column was suggested on the basis of analytical studies. In this paper, I explain the Joint of PHC pile to steel tube column and more detail of analysis

To overcome disadvantages of usual spread foundation in large space structure, some prototypes of a joint of the PHC pile to steel pipe column that directly connects a column to a PHC pile are analytically studied. With the consideration of strength requirement and stress concentration of joint of the PHC pile to column, we suggest the most appropriate one.

현대 목조 구조물은 일반적으로 접합철물인 연결재를 이용하여 접합된다. 그리고 목조 구조물에서 다수의 연결재를 사용한 접합부는 반강접 접합부를 만든다. 목조 구조물에 접합부가 핀접합으로 설계될 경우에 접합부를 통해 전달되는 하중이 과소 평가되고 이것은 접합부의 저항능력 부족을 초래한다. 목조 구조물의 접합부를 완전 강접합으로 고려할 경우에 접합에 필요한 접합철물의 양이 과도하게 증가 할 수 있다. 이것은 미적인 요소 뿐만 아니라 시공성과 경제성을 저하시킨다. 접합부의 합리적인 강성에 대한 추정은 목조 구조물의 합리적인 접합부의 설계에 필수적인 요소이다. 이 논문은 목조 구조물의 구조설계를 쉽게 수행할 수 있도록 도움을 주기 위하여 2면 전단접합에 대하여 구조설계에서 널리 이용되는 상용 프로그램을 사용하여 접합부의 근사적인 강성을 나타낼 수 있는 해석 모델링 기법을 제안한다. 제안된 근사해석 모델링 기법은 휨 모멘트, 인장에 대한 실험 결과와 해석결과를 비교하여 접합부의 거동을 나타낼 수 있다는 것을 확인하였다.

최근, 모듈러 구조 시스템은 공기를 단축시킬 수 있는 장점으로 인해 건설 현장에 적용되고 있다. 모듈러 구조시스템은 단위 모듈로 구성되며, 모듈과 모듈의 볼트접합을 위해 보-기둥 접합부에 개구부를 가공하게 된다. 일반적으로 모듈러 구조시스템은 기존 철골모멘트골조와 유사한 하중전달체계를 가지는 것으로 가정하여 설계된다. 이와 같은 설계 가정의 타당성을 확보하기 위해, 단위 모듈의 보-기둥 접합부에 대한 회전 성능이 파악되어야 한다. 본 연구에서는 개구부의 구조적 영향이 고려된 접합부의 회전성능을 파악하기 위해 유한요소해석을 수행하였다. 해석결과 단위모듈은 충분한 변형능력을 가지고 안정적인 이력거동을 하는 것으로 나타났으며, 단위모듈의 접합부는 부분강접 접합부로 분류되었다. 또한 본 연구에서는 단위모듈의 비선형 골조 해석을 위한 간단한 스프링 모델을 개발하였으며, 단위 모듈의 비선형 이력 거동을 구현하기 위해 Ramberg-Osgood 이력 모델을 제시하였다.