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        검색결과 268

        101.
        2015.10 구독 인증기관·개인회원 무료
        The population of managed honey bees has been dramatically declining the recent past in worldwide. The one of most common disease of bees is nosemosis, the nosemosis is caused by microsporidia in the genus Nosema. Nosema apis and N. ceranae have been described as honeybee pathogens. These microsporidia are highly evoloved fungi with an obligately intracellular parasitic lifstyle. The disease causes significant detriment to honey production and results in economic losses. In our knowledge, Fumagillin is the only antibiotic approved for control of nosemosis in honey bees, however this antibiotic may have unintended effects on the honey bee host, ultimately contributing to increased prevalence and pathogenicity of Nosema. Therefore, we screened anti-Nosema substances from entomopathogenic fungal culture filtrates using in vitro polar tube germination assay. These fungal metabolites are employed as antibiotic agents. As results, Total 3 samples (23% of 13 total samples) showing the germinating inhibition against N. ceranae. This screening method may be useful for the detection of anti-Nosema substances from various samples and selected samples in this study may be a good feature to be used in the development of a new biocontrol method of nosemosis.
        102.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A series of injection and drainage test were conducted on an circular acrylic tube to investigate the pressure generated by the accumulated fill materials inside a circular acrylic tube structure. The acrylic tube was filled by means of gravity filling with a slurry material having an average water content of 700%. The water head during the filling process was 1.8m and the bottom pressure during initial filling was 20.18kPa. The recorded stress at the sides of the acrylic tube was 17.89kPa during the filling process and was reduced to 13.58kPa during the leaving process. Continuous drainage of the acrylic tube has greatly influenced the stresses around the tube structure. As the water is gradually allowed to overflow, the generated pressure at the topmost pressure sensor of the tube was reduced further to 2.17kPa. Eventually, the initially liquid state slurry material transforms into plastic state after water has dissipated and substantial soil particles are deposited in the acrylic tube. The final water content of the deposited silt inside the acrylic tube after the test was 42%. It was found that the state of stresses(geo-static earth pressures) in the acrylic tube was anisotropic rather than isotropic.
        4,000원
        103.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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.
        4,000원
        104.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        So far, square concrete filled tubular(CFT) columns have been used in a limited width thickness ratio. The reason is that local buckling occurs in steel tube easily. Once the local buckling occurs, the confinement effect of steel tube on concrete disappears. In this study, we developed welded built-up square steel tube with reinforcement which are placed at the center of the tube width acts as an anchor. 3 specimens of slender welded built-up square CFT columns and 3 specimens of slender welded built-up square steel tube columns were manufactured with parameters of width(B) of steel tube, width thickness ratio(B/t). we conducted a experimental test on the 6 specimens under eccentric load, and evaluated the structural resistance and behavior of 6 specimens.
        4,000원
        105.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, we developed the hydraulic leveling jack(HLJ) with double-tube type structure which could be applicable to excessive lateral load area. In order to develop HLJ, the design requirements, such as the vertical and lateral loads where applied to hydraulic jack, were selected. To verify the structural stability of the HLJ, the structure analysis was performed. In order to verify the operational performance and structural stability of the developed HLJ, test bench was designed. The performance of HLJ was verified via various test using test bench.
        4,000원
        106.
        2015.04 구독 인증기관 무료, 개인회원 유료
        An experiment have been conducted to investigate the behavior of dredged fills on flexible containers (scale model geotextile tubes). The study was focused on the development of geotextile strain. The model geotextile tube is made of woven geotextile material. Results showed that during the dewatering stage, the tube height decreases and the tube width increases. This increases the density of the confined fill material and the tensile reaction of the tube. The compaction effect on top of the geotextile tube decreases as the tube height reduces. On the other hand, the confinement effect at the sides of the geotextile tube increases as the tensile reaction intensifies. As a result, The geotextile strain increases as the value of the coefficient of lateral pressure is increased.
        3,000원
        107.
        2015.04 구독 인증기관 무료, 개인회원 유료
        The acrylic tube, referred to as geocell in this paper, is 2.19m long with an inner diameter of 280mm. Both ends of the acrylic tube were covered with permeable geotextile sheets to allow water dissipation. The dredged soil fill material is hydraulically filled into the acrylic tube in the form of soil-water mixture (slurry). Load cells oriented in the vertical and horizontal directions were installed inside the geocell to measure the horizontal and vertical pressures inside the cylindrical tube. The pressure readings are collected through a data logger and interpreted by a desktop computer. The pressure distribution inside the geocell based on the load cell readings are closely related to the theoretical Ko and Ka conditions.
        3,000원
        108.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        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
        4,000원
        109.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적 : 본 연구에서는 임상 작업치료사들이 간헐적 구강식도관을 적절하게 적용할 수 있는 기준에 대한 근 거자료를 제공하고, 간헐적 구강식도관에 대한 인식을 높이고자 하였다. 연구방법 : 간헐적 구강식도관 적용이 의뢰된 자 57명을 대상으로 작업치료사가 간헐적 구강식도관을 적 용하였다. 의무기록 열람을 통해 대상자들의 특징을 조사하였고, 인지 기능 평가를 위해 한국형 간이 정 신상태 검사(Korean version of Mini Mental State Examination; K-MMSE)를 시행하였다. 훈련을 통해 간헐적 구강식도관 적용을 성공한 군과 실패한 군으로 나누어 두 군의 특징을 비교하였다. 결과 : 57명 중 45명(78.9%)은 간헐적 구강식도관을 적용하였으나, 12명(21.1%)은 간헐적 구강식도관 적 용을 실패하여 영양 섭취 방법을 변경하지 않았다. 실패 원인으로는 인지 저하 4명 (33.3%), 적용 방법에 대한 거부 3명(25.0%), 구역 반사 3명(25.0%), 폐렴 2명(16.7%)순으로 조사되었다. K-MMSE 점수에 서 간헐적 구강식도관 적용을 성공한 군의 점수가 실패한 군의 점수보다 유의하게 높았다. 그러나 각 군의 평균 연령, 발병일로부터 연하재활치료 시작일까지의 평균 기간, 발병일로부터 간헐적 구강식도관 훈련일까지의 평균 기간, 연하재활치료 시작일부터 간헐적 구강식도관 훈련일까지의 평균 기간, 간헐적 구강식 도관 훈련 기간에서는 유의한 차이가 없었다. 결론 : 간헐적 구강식도관 적용은 처치 방법과 관리에 대해 충분한 설명을 들은 환자 및 보호자가 동의하였을 경우 실시가능하다. 또한, 인지 기능과 구역 반사가 간헐적 구강식도관을 적용하기에 적합한 환자에게는 과도기적 영양 지원 방법으로 뿐만 아니라 치료적 목적으로 고려될 수 있다고 사료된다. 그러나 폐렴, 역류 등이 의심되는 경우 적용을 제한할 것을 권고하고 장기간 안전하게 적용하기 위해서는 환자 및 보호자의 철저한 관리가 요구된다.
        4,300원
        110.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, modified catalytic chemical vapor deposition (CCVD) method was applied to control the CNTs (carbon nanotubes) growth. Since titanium (Ti) substrate and iron (Fe) catalysts react one another and form a new phase (Fe2TiO5) above 700℃, the decrease of CNT yield above 800℃ where methane gas decomposes is inevitable under common CCVD method. Therefore, we synthesized CNTs on the Ti substrate by dividing the tube furnace into two sections (left and right) and heating them to different temperatures each. The reactant gas flew through from the end of the right tube furnace while the Ti substrate was placed in the center of the left tube furnace. When the CNT growth temperature was set 700/950℃ (left/right), CNTs with high yield were observed. Also, by examining the micro-structure of CNTs of 700/950℃, it was confirmed that CNTs show the bamboo-like structure.
        4,000원
        111.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A powder-in-sheath rolling (PSR) process utilizing a copper alloy tube was applied to a fabrication of a multi-walled carbon nanotube (CNT) reinforced aluminum matrix composite. A copper tube with an outer diameter of 30 mm and a wall thickness of 2 mm was used as a sheath material. A mixture of pure aluminum powders and CNTs with the volume contents of 1, 3, 5 vol% was filled in the tube by tap filling and then processed to 93.3% height reduction by a rolling mill. The relative density of the CNT/Al composite fabricated by the PSR decreased slightly with increasing of CNTs content, but showed high value more than 98%. The average hardness of the 5%CNT/Al composite increased more than 3 times, compared to that of unreinforced pure Al powder compaction. The hardness of the CNT/Al composites was some higher than that of the composites fabricated by PSR using SUS304 tube. Therefore, it is concluded that the type of tube affects largely on the mechanical properties of the CNT/Al composites in the PSR process.
        4,000원
        112.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서 고투과도를 갖는 실리카 분리막은 콜로이달 실리카 졸과 고분자형 실리카 졸 두 가지를 DRFF법과SRFF법으로 다공성 금속 지지체 위에 코팅하여 제조되었다. 실리카 졸은 졸-겔법으로 테트라에톡시실란(TEOS)에 의하여 제조되었고, 각각의 졸은 동적광산란법(DLS), 전계방사 주사전자현미경(FE-SEM), 질소 흡착법 등을 이용하여 그 특성을 평가하였다. 다공성 금속 지지체위에 콜로이달 실리카 졸로 중간층을 형성하여 치밀한 구조의 실리카 층을 형성한 후 그 위에 분리층으로 고분자형 실리카 졸을 코팅하여 핀홀을 줄이는 방법으로 기체분리용 분리막을 제조하였다. FE-SEM으로 분리막의코팅 층을 분석한 결과 분리층은 중간층보다 침밀한 구조를 가지고 있음을 확인하였고 기체투과 결과 수소 투과도 (6.63-9.21) × 10-5 mol⋅m-2⋅s-1⋅Pa-1 분포를 보였다.
        4,000원
        114.
        2014.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ammonia is one of typical index substances of environmental odor. This study describes a rapid and simpleadsorption tube type detector to be able to measure the level of strict emission standards with quantitativeconcentration of gaseous ammonia as the regulations are enhanced. a gas detector tube can be measured theammonia gas concentration of 0.23ppm, 0.5ppm, 1ppm, 1.5ppm and 2ppm through the relation between theSampling rate Kog (=DA/L) and the discoloration reaction rate by physico-chemical analysis. Also this study canbe predicted the relation between the sampling volume and the sampling time. and it can be designed to measuringthe range of various concentrations. In this case study, an optimum design was found with an sampling rate, 42ml/min and with a tube diameter, 3.0mm. Adsorption and diffusion rate was evaluated by Fick's law.
        4,000원
        115.
        2013.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to develop the automatic fin tube cutting machine, equipped with semi-automatic supplying board, automatic transfer equipment, fin tube holder, and cutting equipment assembly for the effective and safe fin tube cutting. The development of the automatic fin tube cutting machine resulted in improving 150% of productivity, 300% of cutting length precision, and 230% of a vertical angle precision on the cutting plane. In addition, we were able to secure safety of the workers and to automate production management, and further to reduce environmental pollution by recycling cutting chips.
        4,000원
        116.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        터널을 통과하는 고속 열차로 인해 발생하는 열차풍에 의한 영향은 갑작스런 압력장의 변화 등으로 인한 충격파의 전달 과정의 정확한 분석이 필수적이다. 이에 본 논문에서는 근사 리만 솔버를 이용한 단상 압축성 유체장의 충격파 전달 과정의 수치해석 기법을 제시하였다. 통상 이용되는 이상기체 상태 방정식을 대신하여 Tait 상태방정식을 이용하였으며, 1차원에서의 오일러 고정 격자계에서의 고압과 저압의 영역을 구분하는 막이 파열됨으로써 발생하는 충격파의 전파를 해석하였다. 본 논문에서 제시하는 기법을 검증하기 위하여 이전의 해석적 기법에 의한 연구 결과와 비교하여 잘 일치함을 나타내었으며, 범용 전산 유체 역학 프로그램을 이용한 해석을 수행하여 비교함으로써 유용성 및 효율성을 검증하였다.
        4,000원
        117.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents the theoretical analysis for the flow driven by surface tension and gravity force in an inclined circular tube. The governing equation is developed to describe the displacement of a Newtonian fluid that continuously flew into a circular tube by surface tension, which represents a second-order, nonlinear, nonhomogeneous and ordinary differencial form. It was found that the theoretical predictions of the governing equation were excellent agreement with the unsteady state solutions for horizontal tube and the results of force balance equation for steady state.
        4,000원
        118.
        2013.04 구독 인증기관 무료, 개인회원 유료
        This study investigates the stress-strain relations of internally confined hollow concrete filled tube pier reinforced with GFRP tube by uniaxial compression test. The confined concrete subjected multi-axial stresses have been known as the strength of concrete increases significantly. Many researchers have studied in confining effects of CFT which have only outer GFRP tube. In this study, specimens reinforced with outer and inner GFRP tube were tested by uniaxial compression test. To investigate the influence of concrete strength increase by confining conditions in GFRP tube, 13 specimens with different thickness of tube, hollowness ratio and nominal concrete strength were tested and compared with Steel tube.
        3,000원
        119.
        2013.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the segmented-in-series solid-oxide fuel cells (SIS-SOFCs), fabrication techniques which use decalcomania paper have many advantages, i.e., an increased active area of the electrode; better interfacial adhesion property between the anode, electrolyte and cathode; and improved layer thickness uniformity. In this work, a cell-stack was fabricated on porous ceramic flattened tube supports using decalcomania paper, which consists of an anode, electrolyte, and a cathode. The anode layer was 40μm thick, and was porous. The electrolyte layers exhibited a uniform thickness of about 20μm with a dense structure. Interfacial adhesion was improved due to the dense structure. The cathode layers was 30μm thick with porous structure, good adhesion to the electrolyte. The ohmic resistance levels at 800, 750 and 700˚C were measured, showing values of 1.49, 1.58 and 1.65Ω·cm2, respectively. The polarization resistances at 800, 750 and 700˚C were measured to be 1.63, 2.61 and 4.17cm2, respectively. These lower resistance values originated from the excellent interfacial adhesion between the anode, electrolyte and cathode. In a two-cell-stack SOFC, open-circuit voltages(OCVs) of 1.915, 1.942 and 1.957 V and maximum power densities(MPD) of 289.9, 276.1 and 220.4mW/cm2 were measured at 800, 750 and 700˚C, respectively. The proposed fabrication technique using decalcomania paper was shown to be feasible for the easy fabrication of segmented-in-series flattened tube SOFCs.
        4,000원
        120.
        2012.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Concrete filled steel tube (CFT) columns have been widely used in moment resisting frame structures both in seismic zones. This paper discusses the design of such members based on the advanced methods introduced in the 2005 AISC Specification and the 2005 Seismic Provisions. This study focuses particularly on design following both linear and nonlinear methods utilizing equivalent static and dynamic loads for low-rise moment frames. The paper begins with an examination of the significance of pseudo-elastic design interaction equations and the plastic ductility demand ratios due to combined axial compressive force and bending moment in CFT members. Based on advanced computational simulations for a series of five-story composite moment frames, this paper then investigates both building performance and new techniques to evaluate building damage during a strong earthquake. It is shown that 2D equivalent static analyses can provide good design approximations to the force distributions in moment frames subjected to large inelastic lateral loads. Dynamic analyses utilizing strong ground motions generally produce higher strength ratios than those from equivalent static analyses, but on more localized basis. In addition, ductility ratios obtained from the nonlinear dynamic analysis are sufficient to detect which CFT columns undergo significant deformations.
        4,500원