Publications by authors named "Youngjun You"

Direct wafer bonding is one of the most attractive techniques for next-generation semiconductor devices, and plasma has been playing an indispensable role in the wider adoption of the wafer bonding technique by lowering its process temperature. Although numerous studies on plasma-assisted direct wafer bonding have been reported, there is still a lack of deep investigations focusing on the plasma itself. Other than the plasma surface treatment, the wafer bonding process includes multiple steps such as surface cleaning and annealing that require comprehensive studies to maximize the bonding strengths.

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The repair of underwater concrete structures is usually difficult work, requiring specialized materials and installation systems. This paper presents a carbon-textile-reinforced concrete (TRC) grouting system for underwater repair of concrete structures. One multi-purpose grout and two types of underwater grouts were considered in this study, and the bond performance between the substrate and grout was evaluated by a bi-surface shear test with cubic specimens.

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This paper presents a new textile-reinforced concrete (TRC) installation method for strengthening structurally deficient or damaged reinforced concrete (RC) structures with grouting. In this study, cementitious grout was used as a matrix for the TRC system. TRC coupon specimens with different lap-splice lengths were tested under tension to determine the minimum textile lap-splice length.

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A textile reinforced concrete (TRC) system has been widely used for repair and strengthening of deteriorated reinforced concrete (RC) structures. This paper proposes an accelerated on-site installation method of a TRC system by grouting to strengthen deteriorated RC structures. Four RC slabs were strengthened with one ply of carbon textile grid and 20 mm-thick cementitious grout.

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Colorful indoor organic photovoltaics (OPVs) have attracted considerable attention in recent years for their autonomous function in internet-of-things (IoT) devices. In this study, a solution-processed TiOlayer in a metal-oxide-metal (MOM) color filter electrode is used for light energy recycling in P3HT:ICBA-based indoor OPVs. The MOM electrode allows for tuning of the optical cavity mode to maximize photocurrent production by modulating the thickness of the TiOlayer in the sandwich structure.

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Construction with precast or prefabricated elements requires the connecting of structural joints. This study presents an accelerated construction method to strengthen reinforced concrete (RC) slab-type elements in flexure using precast lap-spliced textile-reinforced concrete (TRC) panels. The objectives of this study are to identify the tensile behavior of a TRC system with lap-spliced textile, and to experimentally validate the performance of the proposed connecting method by flexural failure test for the concrete slabs strengthened by TRC panels with lap-spliced textile.

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Although carbon textile reinforcement widely used to replace the steel reinforcing bars but the bonding strength of carbon textile is generally much smaller than that of common steel bars. This study examines the strengthening effect of concrete slab-type elements strengthened in flexure by carbon textile reinforcement according to the surface coating of textile and the amount of reinforcement. The effect of the surface coating of textile on the bond strength was evaluated through a direct pullout test with four different sizes of coating material.

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This study investigated the hardening process of alkali-activated material (AAM) mortar using calcium sulfoalumiante (CSA) expansive additive (CSA EA), which accelerates the initial reactivity of AAMs, and subsequent changes in ultrasonic pulse velocity (UPV). After the AAM mortar was mixed with three different contents of CSA EA, the setting and modulus of elasticity of the mortar at one day of age, which represent curing steps, were measured. In addition, UPV was used to analyze each curing step.

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Textile reinforced concrete (TRC) has widely been used for strengthening work for deteriorated reinforced concrete (RC) structures. The structural strengthening often requires accelerated construction with the aid of precast or prefabricated elements. This study presents an innovative method to strengthen an RC slab-type element in flexure using a precast panel made of carbon TRC.

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This paper deals with flexural strengthening of reinforced concrete (RC) slabs with a carbon textile reinforced concrete (TRC) system. The surface coating treatment was applied to a carbon grid-type textile to increase the bond strength. Short fibers were incorporated into the matrix to mitigate the formation of shrinkage-induced cracks.

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Herein, we introduce an interdigitated horizontal electrode (IHE) structure with a metal-based electron-collecting (or -injecting) electrode and a hole-collecting (or -injecting) electrode composed of a conductive polymeric material that has a nanoscale distance and is horizontally separated. In the IHE, a metal electrode is fabricated on a silicon-oxide substrate, and a self-assembled monolayer (SAM) is selectively bonded to the metal and the oxide to form a conductive polymer electrode by dip coating. Each of the SAM materials is composed of a head part bonded to the substrate surface and a tail part that is hydrophilic or hydrophobic.

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The rule of mixtures (ROM) method is often used to estimate the tensile strength of fiber reinforced polymers (FRPs) reinforcing bars (rebars). Generally, the ROM method predicts the FRP rebars' modulus of elasticity adequately but overestimates their tensile strength. This may result from defects occurred during manufacture that prevent the used materials from exhibiting a sound performance and the shear-lag phenomenon by transmission of external forces through the surface of the rebar having a circular cross section.

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