• 한국인터넷방송통신학회논문지
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• 제11권2호
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• pp.35-40
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• 2011

본 논문에서는 복합재 샌드위치 구조를 가지는 이중대역(1.575, 2.645 GHz) 안테나의 충격 및 굽힘 특성에 관하여 연구하였다. 평면형 안테나에 복합재료인 Carbon Fiber Reinforced Plastic, Glass Fiber Reinforce Plastic을 접착하여 기계적 성능을 향상시킬 수 있다. 시험 규격 ASTM D7137에 따라 충격 시험과 시험규격 ASTM C393, MIL-STD401B에 따라 굽힘 시험을 실시한 후, S11 및 이득 측정을 통하여 안테나의 전기적 성능과 기계적 성능을 확인하였다. 제안된 안테나는 복합재료 보강 전보다 약 4배인 충격 하중 4 kN, 약 2배인 400 N의 굽힘 하중을 견디며, GPS, DMB 대역에서 6 dBi, 4.6 dBi의 이득을 가진다. 복합재 샌드위치 구조는 구조체 또는 운송체 표면에 적용 가능함을 확인하였다.

• 신재생에너지
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• 제16권3호
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• pp.1-12
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• 2020

Shingled technology is the latest cell interconnection technology developed in the photovoltaic (PV) industry due to its reduced resistance loss, low-cost, and innovative electrically conductive adhesive (ECA). There are several advantages associated with shingled technology to develop cell to module (CTM) such as the module area enlargement, low processing temperature, and interconnection; these advantages further improves the energy yield capacity. This review paper provides valuable insight into CTM loss when cells are interconnected by shingled technology to form modules. The fill factor (FF) had improved, further reducing electrical power loss compared to the conventional module interconnection technology. The commercial PV module technology was mainly focused on different performance parameters; the module maximum power point (Pmpp), and module efficiency. The module was then subjected to anti-reflection (AR) coating and encapsulant material to absorb infrared (IR) and ultraviolet (UV) light, which can increase the overall efficiency of the shingled module by up to 24.4%. Module fabrication by shingled interconnection technology uses EGaIn paste; this enables further increases in output power under standard test conditions. Previous research has demonstrated that a total module output power of approximately 400 Wp may be achieved using shingled technology and CTM loss may be reduced to 0.03%, alongside the low cost of fabrication.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1511_1512
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• 2009

This paper presents a polarization switching antenna integrated with silicon RF MEMS SPDT switches in the form of a package. A low-loss quartz substrate made of SoQ (silicon-on-quartz) bonding is used as a dielectric material of the patch antenna, as well as a packaging lid substrate of RF MEMS switches. The packaging/antenna substrate is bonded with the bottom substrate including feeding lines and RF MEMS switches by BCB adhesive bonding, and RF energy is transmitted from signal lines to antenna by slot coupling. Through this approach, fabrication complexity and degradation of RF performances of the antenna due to the parasitic effects, which are all caused from the packaging methods, can be reduced. This structure is expected to be used as a platform for reconfigurable antennas with RF MEMS tunable components. A linear polarization switching antenna operating at 19 GHz is manufactured based on the proposed method, and the fabrication process is carefully described. The s-parameters of the fabricated antenna at each state are measured to evaluate the antenna performance.

• 마이크로전자및패키징학회지
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• 제22권1호
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• pp.51-54
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• 2015

An electro-plating technology on a cured isotropic conductive pattern with a hybrid Cu paste composed of resin matrix, copper, and solder powders has been developed. In a conventional technology, Ag paste was used to perform a conductive pattern on a PCB or silicon substrate. From previous research, the electrical conductive mechanism and principle of the hybrid Cu paste were concisely investigated. The isotropic conductive pattern on the PCB substrate was performed using screen-printing technology. The optimum electro-plating condition was experimentally determined by processing parameters such as the metal content of the hybrid Cu paste, applied current density, and time for the electroplating in the plating bath. The surfaces and cross-sections were observed using optical and SEM photographs. In conclusion, the optimized processing conditions for Cu electro-plating technology on the conductive pattern were a current density of $40mA/cm^2$ and a plating time of 20min on the hybrid Cu paste with a metal content of 44 vol.%. More details of the mechanical properties and processing conditions will be investigated in further research.

• 펄프종이기술
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• 제31권1호
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• pp.72-79
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• 1999

The binder plays important roles in determining the quality of pigment coating. In addition to its primary role of binding the pigment to the base paper, the binder performs several other important functions. The binder, also referred to as the adhesive, is the dominant in the aqueous phase of the formulation. Thus it plays a major role in determining viscosity, rheology, water release, and setting time for the coating. Latices based on styrene-butadiene dominate the market for synthetic paper coating binders. Consumption is high and is expected to increase further due to the present tendeyncy toward high-solids coating. The purpose of this study is understanding the impact of various parameters of latex(i.e. Tg, Particle size) affecting prontabilities and optical properties of the coated papers, as well as providing basic information on the use of amphoteric latex for improving print qualities of coated papers. Recently, amphoteric latices, Which are cationic at low pH's but turn anionic at high pH's have attracted interests of paper scientists and engineers. Therefore we investigated the effect of the Tg(glass transition temperature) and particle size of amphoteric latex on the coating qualities. We also studied the effect of mixing ratios (Amphoteric / Anionic)of latex on the coating qualities. Our results showed that Tg and particle size of amphoteric latex have to be controlled for optimizing coated paper qualities. The formulation consisting of 10 parts of amphoteric latex and 5 parts of anionic latex gave best results in ink receptivity, smoothness, air permeability, opacity and sheet gloss. If the results hold for the industrial paper coatings, the amount of expensive amphoteric latex can be reduced while achieving best available printing quality.

• 한국구조물진단유지관리공학회 논문집
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• 제19권1호
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• pp.35-44
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• 2015

본 연구에서는 CSA를 혼입한 폴리머 시멘트 모르타르의 강도, 흡수율, 염화 이온 침투 깊이, 중성화 깊이, 길이변화 및 내약품성에 미치는 영향에 대하여 실험적으로 구명하였다. 그 결과, CSA를 혼입한 폴리머 시멘트 모르타르의 압축, 휨, 인장 및 부착강도는 CSA 첨가량 및 폴리머-시멘트비가 증가함에 따라 증가하였다. 흡수율은 CSA 첨가량 및 폴리머-시멘트비가 증가함에 따라 감소하였다. 길이변화는 CSA 첨가량 및 폴리머-시멘트비가 증가함에 따라 감소하였다. 염화 이온 침투깊이 및 중성화 깊이는 CSA 첨가량 및 폴리머-시멘트비가 증가함에 따라 감소하였다. 또한, 내약품성은 CSA 첨가량 및 폴리머-시멘트비가 증가함에 따라 감소하였다. 이와 같은 강도 및 내구성 개선은 EVA 폴리머의 높은 인장강도에 기인하며, EVA 폴리머 및 CSA 혼입에 의하여 시멘트 수화물과 골재사이의 부착력이 개선되기 때문이라 판단된다.

• Journal of Biosystems Engineering
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• 제18권4호
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• pp.344-350
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• 1993

The purpose of this study is to develop design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage. The main results of this study are as follows. 1. A wheel-lug ought to receive a special resistance in downward direction which resists the lug's upward motion on wet sticky soil surface. The authors introduce a new academic name of the "lift resistance(上昇抵抗力, 상승저항력)" for such a force which resists retraction of a wheel lug from the soil in the upward trochoidal motion. This force is composed of the frictional force acting on the trailing and the leading lug side, and the "perpendicular adhesion(鉛直付着力, 연직부착력)" acting on the lug face and the undertread face on adhesive soil. 2. The "lift resistance ratio(上昇抵抗力係數, 상승저항력계수)" and the "perpendicular adhesion ratio(鉛直付着力係數, 연직부착력계수)" were defined, which are something similar to the definition of the motion resistance ratio, the traction coefficient, etc. 3. The design equation of the optimum weight of a rotary tiller mounted on the tractor derived by calaulating the forces acting on the rotary blades. 4. The design equations to calculate optimum specifications and dimensions such as weight, engine horsepower, etc. of the tractor necessary to perform stable rotary tillage were derived. It becomes clear that the optimum weight of a rotary tiller and a tractor can be estimated in planning design by means of putting about 21 design factors of the target into the equation. These equations are useful for planning design to estimate the optimum dimensions and specifications of a rotary tiller as well as a tractor by the use of known and/or unknown design parameters.

• 접착 및 계면
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• 제5권2호
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• pp.14-26
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• 2004

For reliable determination of mechanical characteristics of adhesively bonded joints used e.g. as input data for computer-aided design of complex components, the thick-adherend tensile-shear test according to ISO 11003-2 is the most important material testing method. Although the total displacement of the joint is measured across the polymer layer directly in the overlap zone in order to minimize the influence of the stepped adherends, the substrate deformation must be taken into account within the framework of the evaluation of the shear modulus and the maximum shear strain, at least when high-strength adhesives are applied. In the standard ISO 11003-2 version of 1993, it was prescribed to perform the substrate deformation correction by means of testing a one-piece reference specimen. The authors, however, pointed to the excessive demands on the measuring accuracy of the extensometers connected with this technique in industrial practice and alternatively proposed a numerical deformation analysis of a dummy specimen. This idea of a mathematical correction was included in the revised ISO 11003-2 version of 2001 but in the simplified form of an analytical method based on Hooke's law of elasticity for small strains. In the present work, it is shown that both calculation techniques yield considerably discordant results. As experimental assessment would require high-precision distance determination (e.g. laser extensometer), finite element analyses of the deformation behavior of the bonded joint are performed in order to estimate the accuracy of the obtained substrate deformation corrections. These simulations reveal that the numerical correction technique based on the finite element deformation modeling of the reference specimen leads to considerably more realistic results.

• 콘크리트학회논문집
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• 제14권4호
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• pp.549-555
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• 2002

탄소섬유쉬트는 철근의 약 10배에 달하는 인장강도를 지니고 있으나, 보강 특성상 접착제를 사용한 일체화가 선행되어져야하기 때문에 부착으로 인한 강도저감요인을 배제할 수가 없다. 결국 탄소섬유쉬트의 인장강도를 최대한 발휘하기 위해서는 부착파괴를 방지할 수 있는 합리적 설계가 이루어져야 한다. 현재까지 부착성능과 관련한 많은 연구가 진행되었지만 부착길이 결정하는 부착강도에 대한 연구는 미흡하였으며, 설계에 반영할 수 있는 기준 역시 미진한 상태이다. 본 연구에서는 일본 규준 안 및 국내 제조사가 제시하고 있는 설계용 부착강도를 기준으로 부착길이를 검토하였으며, 부착성능에 영향을 미칠 젓으로 판단되는 프라이머 도포량 및 에폭시 강도를 변수로 실험을 실시하였다. 본 실험결과에 의하면, 현재 적용 강도는 모두 안전측으로 나타났으며, 설계용 부착강도는 최대 $\tau$a =8 kgf/$\textrm{cm}^2$ 까지 가능할 것으로 판단된다.

• Elastomers and Composites
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• 제49권4호
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• pp.275-283
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• 2014

건축용 접착제로 활용되고 있는 부틸고무는 주로 시트의 형태로 사용된다. 본 연구에서는 컴퓨터 해석을 통해 부틸고무 시트 압출용 다이를 설계하였다. 압출용 다이의 내부는 크게 매니폴드와 랜드로 나뉜다. 매니폴드는 다이중앙에서 유입되는 재료가 폭 방향으로 흐름이 이루어 지도록 하는 역할을 한다. 랜드는 재료가 흐름 방향으로 균일하게 흐르게 하여 균일한 두께의 시트가 성형되도록 한다. 다이는 매니폴드와 랜드 외에도 아일랜드를 설치하여 흐름의 안정을 주도록 하는 경우가 많다. 본 연구에서는 컴퓨터 해석을 통하여 다이에서 매니폴드의 각도와 길이, 랜드 길이 그리고 아일랜드를 설계 변수로 하여 다이 출구에서 다이 폭 방향으로 균일한 흐름이 형성되도록 하는 최적의 다이형상을 연구하였다.