• 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.

• 한국재료학회지
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• 제29권3호
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• pp.183-188
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• 2019

Flexible dye-sensitized solar cells using binder free $TiO_2$ paste for low temperature sintering are developed. In this paste a small amount of titanium gel is added to a paste of $TiO_2$ nanoparticle. Analysis of titanium gel paste prepared at $150^{\circ}C$ shows that it has a pure anatase phase in XRD and mesoporous structure in SEM. The formation of the titanium gel 1-2 nm coated layer is confirmed by comparing the TEM image analysis of the titanium gel paste and the pristine paste. This coating layer improves the excited electron transfer and electrical contact between particles. The J-V curves of the organic binder DSSCs fabricated at $150^{\circ}C$ shows a current density of $0.12mA/cm^2$ and an open-circuit voltage of 0.47 V, while the titanium gel DSSCs improves electrical characteristics to $5.04mA/cm^2$ and 0.74 V. As a result, the photoelectric conversion efficiency of the organic binder DSSC prepared at low temperature is as low as 0.02 %, but the titanium gel paste DSSCs has a measured effciency of 2.76 %.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2003년도 international symposium on advanced powder metallurgy
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• pp.76-77
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• 2003

• International Journal of Concrete Structures and Materials
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• 제4권1호
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• pp.37-43
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• 2010

Theoretical models based on modern interpretations of the morphology and interactions of cement hydration products are developed for prediction of the mechanical properties of hydrated cement paste (hcp). The models are based on the emerging nanostructural vision of calcium silicate hydrate (C-S-H) morphology, and account for the intermolecular interactions between nano-scale calcium C-S-H particles. The models also incorporate the effects of capillary porosity and microcracking within hydrated cement paste. The intrinsic modulus of elasticity and tensile strength of hydrated cement paste are determined based on intermolecular interactions between C-S-H nano-particles. Modeling of fracture toughness indicates that frictional pull-out of the micro-scale calcium hydroxide (CH) platelets makes major contributions to the fracture energy of hcp. A tensile strength model was developed for hcp based on the linear elastic fracture mechanics theories. The predicted theoretical models are in reasonable agreements with empirical models developed based on the experimental performance of hcp.

• 한국건축시공학회지
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• 제11권1호
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• pp.83-90
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• 2011

The purpose of this research is to investigate the effect of AFm formation on the stiffening process of cement paste. High and low alkali sulfate clinkers were used for the experiments. The flow and stiffening behavior of cement paste was investigated using modified ASTM C403 penetration resistance test and oscillatory shear rheology. X-ray powder diffraction (XRD) was used for phase identification associated with stiffening of the paste. It was found from the results that low alkali clinker mixture produced very strong premature stiffening whereas high alkali clinker mixture did not cause premature stiffening. This is because of the large amount of alkali sulfate present in the clinker. Addition of calcium and sodium chloride to the high alkali clinker mixture caused faster stiffening and set.

• 한국인쇄학회지
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• 제26권1호
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• pp.97-111
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• 2008

BLU is a important part of the most representative LCD at flat panel display. In order to supplement the optical special quality which LCD cannot light itself, BLU is an essential property to supply with same brightness on the screen. In this study we have manufactured and characterized the low temperature calcined paste that can be used as a flat light source for LCD BLU. For the phosphor paste and intermediate paste, the low temperature calcined acryl resin was used as the binder. From the result of thermal decomposition measurement, residual carbonaceous materials was found to be less than 0.2wt% at $400^{\circ}C$.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.205-206
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• 2019

This study investigated the fluidity and compressive strength properties of blast furnace slag based non-cement paste containing ferronickel slag powder to evaluate the possibility of use in for cement replacement materials. As a result, the fluidity of non-cement paste showed a higher flow as the mixing ratio of ferronickel slag powder increased. The compressive strengths similar to those of the non-cement paste using only blast furnace slag powder were obtained when 5 and 10% of ferronickel slag powder were used.

• 한국세라믹학회지
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• 제47권5호
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• pp.426-429
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• 2010

The Influence of the character of fly ash on the fluidity of cement paste with a polycarboxylic acid type superplasticizer was investigated in connection with the particle size distribution, unburned carbon content, specific surface area and shape of the fly ash. The fluidity of the fly ash cement paste with an added 20 vol% fly ash increases with an increasing roundness of the fly ash and it decreases with an increasing n-value of the fly ash cement. There is a linear correlation between the roundness/n-value and the fluidity of fly ash cement paste.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.295-298
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• 2003

The principal problems in development of dielectric paste materials for PDP(plasma display panel)are PbO free paste and low melting temperature. We prepared PbO free paste from glasses in the system BaO-ZnO-$B_2O_3-V_2O_5$. DTA, XRD and SEM were used to study and characterize BaO-ZnO-$B_2O_3-V_2O_5$ glasses. PbO free paste developed at this paper has thermal expansion of $74{\times}10^{-7}/^{\circ}C$, DTA transformation point of $460^{\circ}C$, and firing condition of $560^{\circ}C$, 10min.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.524-525
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• 2005

The principal problems in development of dielectric paste materials for PDP(plasma display panel)are PbO free paste and low melting temperature. We prepared PbO free paste from glasses in the system $ZnO-B_2O_3-Bi_2O_3-SiO_2$, DTA, and XRD were used to characterize $ZnO-B_2O_3-Bi_2O_3-SiO$ glasses. In this present study, PbO free paste had thermal expansion of $74\times10^{-7}/^{\circ}C$, DTA transformation point of $470^{\circ}C$, and firing condition of $540^{\circ}C$, 20min.