• Korean Journal of Metals and Materials
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• v.50 no.10
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• pp.785-792
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• 2012

A new flip chip structure consisting of interlocking joints locally surrounded by non-conductive adhesive was investigated in order to improve the contact resistance characteristics and prevent the parasitic capacitance increase. The average contact resistance of the interlocking joints was substantially reduced from $135m{\Omega}$ to $79m{\Omega}$ by increasing the flip chip bonding pressure from 85 MPa to 185 MPa. Improvement of the contact resistance characteristics at higher bonding pressure was attributed not only to the increased contact area between Cu chip bumps and Sn pads, but also to the severe plastic deformation of Sn pads caused during formation of the interlocking-joint structure. The parasitic capacitance increase due to the non-conductive adhesive locally surrounding the flip chip joints was estimated to be as small as 12.5%.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.1-11
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• 2010

The physicochemical characteristics, adhesion power, and conservation of imported tapes repairing documents that consisted of adhesive, carrier, and masking were investigated. Materials related to pressure sensitive adhesive produced in domestic companies were examined also. And then, the performance evaluation of prototype manufactured in our laboratory was undertaken. Both the pressure sensitive tapes were compared. The polyacrylate of adhesive agents such as polyacrylate, starch, Glue, and PVA of imported tapes was best. The adhesion strength, power, reversibility, and stability (deterioration) of imported tapes were analyzed. By comparing results of imported tapes, two adhesive agents were selected finally. The carriers of imported tapes are made of one of papers, cotton sheets, and felts. Major carrier material was a paper. The jutes, conifers, and hardwoods were main ingredient of papers. The durability of Hangi($18{\pm}2g/m^2$) was one and half times superior to imported one.

• Journal of the Korean Society of Safety
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• v.18 no.3
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• pp.81-87
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• 2003

Latex polymers are widely used for adhesive, binder, paint etc. Especially the PVAc(Polyvinyl acetate) latex which manufactured by vinyl acetate and vinyl alcohol as protective colloid is a useful environmentally friendly adhesive. To increase useful property of PVAc latex, this study was carried out for checking thermal characteristics and physical condition of PVAc latex by DSC, FT-IR, Pyrolyzer GC-MS. The activation energies of thermal decomposition for 40, 48, 56, 64% solid content of PVAc latex were found as 28.1-36.0kcal/mol by Kissinger's method and 17.2-22.0kcal/mol by DSC method. Actually, reasonable solid content could be consiered as 56% because of activation energy and adhesive characteristics. According to the effect of protective colloid for 4, 10, 15, 20wt%, the activation energy shows same tendency to both method and in case of l5wt% has been found as the highest activation energy. The mechanism of thermal decomposition was mainly estimated by main chain scission, not by side group on FT-IR analysis. Main component of Pyrolzer GC-MS result were consisted of $CH_3COOH$, $CH_3$, $H_2O$ and light gases(CO, $CO_2$, $CH_4$ etc).

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.886-893
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• 2018

In this study, clinching characteristics of aluminum and galvanized steels were investigated for the application of clinching as a joining technique to aluminum wheelhouse assembly. A6451 aluminium alloy and galvanized steel sheets were joined by hybrid joining(clinching + adhesive bonding). Tensile-shear load and fracture mode of hybrid joints were investigated. Maximum tensile-shear load of hybrid joints was about six times higher than that of clinched joints without adhesive. Energy absorption values of hybrid joints were higher than those of clinched joints without adhesive as well as resistance spot welded steel joints. Developed aluminum wheelhouse assembly showed higher static stiffness than the existing steel parts. Aluminum wheelhouse inner panel unit was 44% lighter than the steel unit, and the final assembled aluminum wheelhouse was 14.6% lighter than the existing steel parts.

• Elastomers and Composites
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• v.58 no.3
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• pp.128-135
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• 2023

To improve the adhesive strength of natural rubber (NR) for a seismic isolation damper, citraconic acid-g-NR (CCA-g-NR) was synthesized via the melt grafting of citraconic acid (CCA) onto NR using an azobisisnomerobutyronitrile (AIBN) initiator. Subsequently, the influence of CCA and AIBN concentrations on the graft ratio G/R (%) and graft efficiency G/E (%) of the CCA-g-NR was investigated. The optimum CCA and AIBN concentrations required to achieve the desired G/R (3.49%) and G/E (49.8%) were found to be 7 phr and 0.13 phr, respectively. Additionally, we studied the influence of CCA-g-NR concentration on the mechanical properties (tensile strength, elongation at break, and modulus at 300%), adhesive strength, and cure characteristics of the rubber compound in the seismic isolation damper. As the concentration of CCA-g-NR increased, the elongation at break and adhesive strength of the compound increased, whereas its tensile strength and modulus at 300% decreased. Moreover, as the concentration increased, the maximum torque decreased and the scorch time was delayed to obtain an optimal vulcanization time.

• Journal of the Korean Society of Industry Convergence
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• v.9 no.1
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• pp.45-50
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• 2006

In order to analyse the properties of the fiber-adhesive that was used as Flocking process we synthesized quaterpolymer with the variation of the types of monomer ratio by emulsion polymerization. We characterized the properties of this adhesive: Differential Scanning Calorimeter(DSC), Thermogravimetry Analysis(TGA), Raman spectroscopy. The polymer was synthesized by changing the using amount of 2-EHAM, and then we investigated the characteristics of glass transition temperature(Tg), melting temperature(Tm), thermal stability and hydroxyl group respectively. The optimum monomer composition was 36.84% EAM, 15.79% MAM, 42.1% 2-EHAM and 5.26% AAc.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.505-508
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• 2006

Self-leveling mortar is walkable bottom mortar which can maintain the horizontality of self fluid and have the the quick-setting quality, the low-human-effort practicable material of high-quality bottom in construction. In accordance with more adhesive strength with bottom side and absorption control, Primer is used for purpose to prevent pin-hole occurrence by self leveling mortar application prior to construction. This study is composed measurement of absorption, adhesive strength. Used material is NP-40 as nonionic emulsifying agent, uses SA-210L as negative ion emulsifying agent, uses APS, SBS as ridical initiator. A result of test, in accordance with image of Primer, as low temperature and application frequency, indicates low absorption rate and adhesive strength, as solid powder and dryness time is increse, absorption rate and adhesive strength lowly shows figure.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.10a
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• pp.236-239
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• 2004

'Structural surface becomes an antenna.' This term, CAS, indicates antenna embedding in structural surfaces. The CAS is composed of several composite laminates and Nomex honeycombs, and microstrip antenna elements are inserted between layers with designed configurations. Constituent materials are selected considering electrical contributions as well as mechanical performances. Antenna design with adhesive films are impossible because cf their thin and rough distributions between honeycomb and substrate. Therefore, adhesive effects on antenna performances in CAS are experimentally investigated, CAS with targeted impedance and radiation characteristics are designed considering adhesive effects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.635-638
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• 2000

It is necessary to work on a vertical plane of workpiece in order to produce a large structure like a ship. These works can be automated by using the robot with permanent magnet wheels. We developed the permanent magnet wheel which can be used by a mobile robot and easily detached. We enhanced an adhesive power by restricting the occurrence direction of magnetic flow. And we also developed a method which weakens adhesive magnetic force by changing magnetic flow with metal pins. We used the load cell and the gaussmeter to measure the characteristics of the adhesive force and magnetic force. We obtained the result that the adhesive power is reduced to 1/3 of normal state by using 4 inducing pins.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.32-38
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• 2007

The purpose of this study is to investigate the cause of fine wrinkles occurred in silky wallpaper and its solution. The characteristics of base papers, wallpapers and adhesives (conventional and modified) were evaluated to find the possibility for the occurrence of fine wrinkles. It was found that the base papers and wallpapers did not cause the occurrence of silky wallpaper. It was concluded that the fine wrinkles in silky wallpaper was caused by the nonuniform distribution of adhesive, the localized shrinkage of adhesive and the breaking the balance between the resistance of wallpaper and shrinkage of adhesive. Three possible solutions for the prevention of the occurrence of fine wrinkles in silky paper were recommended.