• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.409-415
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• 1985

This study has been carried out in order to investigate the bacterial quality of fish meat paste products and the characteristics of isolated thermodurics from the products. Twenty samples of crab-flavored fish stick (Kematsal), 23 samples of plate fish meat paste (Panomuk, Kamaboko), 5 samples of fried fish meat paste (Tigimomuk), 2 samples of roasted fish meat paste (Puduromuk, Chikuwa), 20 samples of fish sausage were collected from processing plants and supermarkets in Pusan, Korea during the period from May to October in 1984. The results obtained are as follows. Amont the samples collected from supermarkets, roasted fish meat paste and fried fish meat paste marked hish counts in coliforms and fungi while very low in the samples of crab-flavored fish stick and plate fish meat paste. Salmonella was not detected in all the samples examined and Staphylococcus aureus was detected only in fried fish meat paste, Thermoduric bacteria were detected less than 10$^2$/g in the samples of crab-flavored fish stick and plate fish meat paste, which might come from subsidiary materials such as starch and seasonings. Among the isolated bacteria, distribution of the proteolytics were more than 87％ and the lipolytics were less than 20％. Gram positive bacteria was more than 70％ in crab-flavored fish stick and plate fish meat paste, 47.3％ in fried fish meat paste. And rod in shape was almost more than 90％ in all the samples. The most heat resistant bacterium isolated from the samples was identified as a Bacillus licheniformis(named B. licheniformis CR-11). The strain showed strong proteolytic activity and also grew well at above 2$0^{\circ}C$. The growth rate and generation time of CR-11 strain were 0.31 hr$^{-1}$ , 2.24 hr at 2$0^{\circ}C$, 0.64 hr$^{-1}$ , 1.09 hr at 3$0^{\circ}C$ and 0.78 hr$^{-1}$ , 0.89 hr at 35$^{\circ}C$. Heat resistance value of the spores of CR-11 strain suspended in phosphate buffer solution was D$_{85}$ $^{\circ}C$=41.9 min, D$_{90}$ $^{\circ}C$=27.9 min, D$_{95}$ $^{\circ}C$=10.2 min, D$_{100}$ $^{\circ}C$=4.3 min (Z=13.8$^{\circ}C$)

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2004.09a
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• pp.233-241
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• 2004

A new alloy definition will be presented concerning increasing demands for the board level reliability of miniaturized interconnections. The damage mechanism for LFBGA components on different board finishes is not quite understood. Further demands from mobile phones are the drop test, characterizing interface performance of different package constructions in relation to decreased pad constructions and therefore interfaces. The paper discusses the characterization of interfaces based on SnPb, SnPbXYZ, SnAgCu and SnAgCuInNd ball materials and SnAgCuInNd as solder paste, the stability after accelerated tests and the description of modified interfaces strictly related to the assembly conditions, dissolution behavior of finishes on board side and the influence of intermetallic formation. The type of intermetallic as well as the quantity of intermetallics are observed, primaliry the hardness, E modules describing the ability of strain/stress compensation. First results of board level reliability are presented after TCT-40/+150. Improvement steps from the ball formulation will be discussed in conjunction to the implementation of lead free materials In order to optimize ball materials for area array devices accelareted aging conditions like TCTs were used to analyze the board level reliability of different ball materials for BGA, LFBGA, CSP, Flip Chip. The paper outlines lead-free ball analysis in comparison to conventional solder balls for BGA and chip size packages. The important points of interest are the description of processability related to existing ball attach procedures, requirements of interconnection properties and the knowledge gained the board level reliability. Both are the primary acceptance criteria for implementation. Knowledge about melting characteristic, surface tension depend on temperature and organic vehicles, wetting behavior, electrical conductivity, thermal conductivity, specific heat, mechanical strength, creep and relaxation properties, interactions to preferred finishes (minor impurities), intermetallic growth, content of IMC, brittleness depend on solved elements/IMC, fatigue resistance, damage mechanism, affinity against oxygen, reduction potential, decontamination efforts, endo-/exothermic reactions, diffusion properties related to finishes or bare materials, isothermal fatigue, thermo-cyclic fatigue, corrosion properties, lifetime prediction based on board level results, compatibility with rework/repair solders, rework temperatures of modified solders (Impurities, change in the melting point or range), compatibility to components and laminates.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.362-364
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• 2003

In this study, sintering behavior of closed-cell type barrier ribs formed via capillary molding route was examined. Sintering of the molded barrier ribs revealed asymmetric shrinkage, leading to distortion of the cells. The effects of the parameters such as solid loading in the paste, presintering temperature, and morphology of the barrier ribs on the sintering shrinkage of the barrier ribs were investigated.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.64.1-64.1
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• 2011

LCD 디스플레이 등에 사용되는 글래스 패널 위에 bare si die를 직접 실장하는 COG 플립칩 패키지의 경우 Au 범프와 ITO 패드 간의 전기적 접속 및 접합부 신뢰성 확보를 위해 접속소재로서 ACF (anisotropic conductive film)가 사용되고 있다. 그러나 ACF는 고가이고 접속피치 미세화에 따라 브릿지 형상에 의한 쇼트 등의 문제가 발행할 수 있어 NCP (non-conductive paste)의 상용화가 요구되고 있다. 본 연구에서는 NCP를 적용한 COG 패키지에 있어서 온도, 압력 등의 열압착 본딩 조건과 NCP 물성이 Au-ITO 접합부의 전기적 및 기계적 특성에 미치는 영향을 조사하였다. NCP는 에폭시 레진과 경화제, 촉매제를 사용하여 다양하게 포뮬레이션을 하였고 DSC (Differential Scanning Calorimeter), TGA (Thermogravimetric Analysis), DEA (Dielectric Analysis) 등의 열분석장비를 이용하여 NCP의 물성과 경화 거동을 확인하였다. 테스트 베드는 면적 $5.2{\times}7.2\;mm^2$, 두께 650 ${\mu}m$, 접속피치 200 ${\mu}m$의 Au범프가 형성된 플립칩 실리콘 다이와 접속패드가 ITO로 finish된 글래스 기판을 사용하였다. 글래스 기판과 실리콘 칩은 본딩 전 PVA Tepla사의 Microwave 플라즈마 장비로 Ar, $O_2$ 플라즈마 처리를 하였으며, Panasonic FCB-3 플립칩 본더를 사용하여 본딩하였다. 본딩 후 접합면의 보이드를 평가하고 die 전단강도로 접합강도를 측정하였다.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.610-616
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• 2011

The effect of curing temperature on basic geopolymeric reactivity and hardening behaviour of blast furnace slag were investigated using the mixture of pulverized slag and several alkaline solutions of relatively high concentration. For the pastes prepared at several different temperatures between 20$^{\circ}C$ and 90$^{\circ}C$, setting time and heat of reaction were examined while mineralogical and morphological examinations were performed for the hardened paste after curing period at same temperature. The geopolymeric reaction of slag was revealed to be accelerated strongly according to the curing temperature regardless of the sort and concentration of the alkaline solution. The increase of concentration of the alkaline solution within 9M and the existence of silicic ion in the solution also promoted the reaction severely. The mineral component and their ratio of the hardened paste were revealed to be influenced by the chemical species and silicic ion contained in alkaline solution rather than by the curing temperature. The higher temperature and longer period of curing stage were effective for the sustained formation of geopolymer and succeed improvement of density and uniformity of morphology of the final hardened body.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.12
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• pp.1837-1842
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• 2010

Studies on alternative energy have been carried out for many decades because of the accelerated exhaustion of fuel. While the efficacy of solar cells is still low in comparison with that of nuclear power, solar cells have been highlighted as potential sources of alternative energy because they are environmentally friendly and have a source of unlimited energy, namely, the sun. In this study, the optimum efficiency of solar cells was simulated as a function of the incident angle of sunlight and the geometric shapes of patterns using MATLAB and MathCAD software. The foremost efficiency of the solar cell was found to be 1.10 when the thickness and width of the patterns were in the range 25-$50{\mu}m$ and 50-$100{\mu}m$, respectively. To achieve the 25 um thick layer, 100,000 cps silver paste and 500 um orifice tip has been successfully implemented with Micro-Dispensing Deposition Writing.

• Journal of the Korean Graphic Arts Communication Society
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• v.26 no.1
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• pp.39-50
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• 2008

We have manufactured Ag pastes for gravure printing by adding different solvent contents. Then the gravure printability and properties of conductive patterns gravure-printed by the different rheology characteristics of pastes were investigated. The dispersity of pastes was increased and the viscosity and shear rate dependence of viscosity for pastes were decreased by increasing the solvent content. Also storage modulus G', loss modulus G" and angular frequency value when G" starts to be bigger than G' of pastes were increased by decreasing the solvent content. These mean a flow drop of paste. As a result of gravure printing using two plates which have different line counts(175line and 350line), conductive patterns printed using 175line were spreaded more but Ag packing, thickness and conductivity of the conductive patterns were better than those printed using 350line. And the spread values of conductive patterns were increased with solvent contents but the best properties for Ag packing, surface roughness and conductivity of the conductive pattern were obtained by paste (3) which has 550cps of viscosity at $100s^{-1}$ and tan ${\delta}$ > 1 at 10rad/s. As a result of gravure printing using 350 line plate and paste (3), the conductive pattern has $1.2{\mu}m$ of film thickness and $1.9{\times}10^{-5}{\Omega}{\cdot}cm$ of conductivity.

• Journal of Microbiology and Biotechnology
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• v.22 no.11
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• pp.1568-1574
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• 2012

Microbiological calcium carbonate precipitation (MCCP) has been investigated for its ability to improve the durability of cement mortar. However, very few strains have been applied to crack remediation and strengthening of cementitious materials. In this study, we report the biodeposition of Bacillus subtilis 168 and its ability to enhance the durability of cement material. B. subtilis 168 was applied to the surface of cement specimens. The results showed a new layer of deposited organic-inorganic composites on the surface of the cement paste. In addition, the water permeability of the cement paste treated with B. subtilis 168 was lower than that of non-treated specimens. Furthermore, artificial cracks in the cement paste were completely remediated by the biodeposition of B. subtilis 168. The compressive strength of cement mortar treated with B. subtilis 168 increased by about 19.5% when compared with samples completed with only B4 medium. Taken together, these findings suggest that the biodeposition of B. subtilis 168 could be used as a sealing and coating agent to improve the strength and water resistance of concrete. This is the first paper to report the application of Bacillus subtilis 168 for its ability to improve the durability of cement mortar through calcium carbonate precipitation.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.474-480
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• 2017

In this study, the evolution of electrical impedance of electric nodes was investigated to determine the setting time of cement paste using the electrical impedance spectroscopy method. The electric nodes were embedded in fresh cement paste and the electrical impedance signatures were continuously monitored. Vicat needle test and semi-adiabatic calorimetry test were also conducted to validate the electrical impedance spectroscopy method. During hydration period of cement paste, the magnitude of conductance gradually increased, and then started to decrease rapidly at a first certain time. After that, the magnitude of conductance gradually decreased at a second certain time. The times of turning point in the curves of magnitude of conductance seem to be related with the setting time by Vicat needle test. Also, the setting times by the electrical impedance spectroscopy method are well posed within the setting period estimated by the semi-adiabatic calorimetry test. Based on the results, it can be concluded that the setting time of cement paste can be effectively monitored through the electrical impedance spectroscopy method.

• Journal of Powder Materials
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• v.22 no.6
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• pp.396-402
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• 2015

The organic binder-free paste for dye-sensitized solar cell (DSSC) has been investigated using peroxo titanium complex. The crystal structure of $TiO_2$ nanoparticles, morphology of $TiO_2$ film and electrical properties are analyzed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Electrochemical Impedance Spectra (EIS), and solar simulator. The synthesized $TiO_2$ nanopowders by the peroxo titanium complex at 150, 300, $400^{\circ}C$, and $450^{\circ}C$ have anatase phase and average crystal sizes are calculated to be 4.2, 13.7, 16.9, and 20.9 nm, respectively. The DSSC prepared by the peroxo titanium complex binder have higher $V_{oc}$ and lower $J_{sc}$ values than that of the organic binder. It can be attributed to improvement of sintering properties of $TCO/TiO_2$ and $TiO_2/TiO_2$ interface and to formation of agglomerate by the nanoparticles. As a result, we have investigated the organic binder-free paste and 3.178% conversion efficiency of the DSSC at $450^{\circ}C$.