• 한국재료학회지
• /
• 제19권9호
• /
• pp.468-472
• /
• 2009

The silver nanofluids were synthesized by the pulsed wire evaporation (PWE) method in a liquid-gas mixture. The size and microstructure of nanoparticles in the deionized water were investigated by a particle size analyzer (PSA), transmission electron microscope (TEM), and scanning electron microscope (SEM). Also, the synthesized nanofluids were investigated in order to assess the stability of dispersion of nanofluid by the zetapotential analyzer and dispersion stability analyzer. The results showed that the spherical silver nanoparticle formed in the deionized water and mean particle size was about 50 nm. Also, when explosion times were in the range of 20$\sim$200 times, the absolute value of zeta potential was less than -27 mV and the dispersion stability characteristic of low concentration silver nanofluid was better than the high concentration silver nanofluid by turbiscan.

• Food Science and Biotechnology
• /
• 제18권4호
• /
• pp.861-866
• /
• 2009

Effects of pressure come-up and holding times on the inactivation of Salmonella enterica and Listeria monocytogenes were evaluated in deionized water, milk, orange juice, and tomato juice with pH 6.76, 6.85, 3.46, and 4.11, respectively. The inoculated samples were subjected to high pressure treatments at 300, 400, and 500 MPa for less than 10 min at $30^{\circ}C$. At 500 MPa, the numbers of S. enterica and L. monocytogenes in deionized water, orange juice, and tomato juice were reduced by more than 6 log CFU/mL during the come-up time. Compared to orange and tomato juices, milk showed a considerable baroprotective effect against S. enterica and L. monocytogenes. At 300 MPa, the D values for S. enterica in milk, orange juice, and tomato juice were 0.94, 0.41, and 0.45 min, while those for L. monocytogenes were 9.56, 1.11, and 0.94 min, respectively. Low pH resulted in a noticeable synergistic effect on the inactivation of S. enterica and L. monocytogenes in orange and tomato juices. Therefore, these results might provide more useful information for designing the entire high hydrostatic pressure (HHP) conditions, taking the come-up time reduction, and food system.

• 한국환경과학회지
• /
• 제13권1호
• /
• pp.89-97
• /
• 2004

An author has been known that A-type zeolite supported with silver ions has excellent antibacterial activity. However, it is no research of concern in the antibacterial activity of eluted silver ions. This study tested the elution of silver ions from A-type zeolite silver ions in deionized distilled water and NaNO$_3$ aqueous solution. In NaNO$_3$ aqueous solution of 74mM to 588mM, it was found that the concentration of silver ions and electric conductivity increased with the increasing concentration of sodium ions, and equilibrated at 15 min, and the ion exchange equilibrium coefficient, k, is 1.3${\times}$10$\^$-3/. However, deionized distilled water is not equilibrated to pass 6 months. A-type zeolite sodium ions showed no antibacterial activity. It was found that antibacterial activity was exhibited even at the concentration of 10 nM of eluted silver ions, and E-coli died with the incorporation of 2.43${\times}$10$\^$8/ Ag ion/cell. antibacterial activity of A-type zeolite silver ions were mainly attributed to hydroxyl radical.

• 한국식품조리과학회지
• /
• 제8권1호
• /
• pp.57-63
• /
• 1992

The purpose of this study was to investigate the rheological and thermal properties of yam starch. Yam starch had a hydrodynamic volume with the intrinsic viscosity,［$\eta$］, of 0.29dl/g deionized water. The values of the intrinsic viscosity of yam starch, determined to pH 2-11, varied between 0.07 to 0.18 dl/g. The highest intrinsic viscosity was obtained at pH 7. At salt concentrations 0-0.2 M NaCl, the intrinsic viscosity of yam starch was decreased up to 0.05 M NaCl concentration then increased to 0.07 M NaCl concentration and remained constant to reach 0.2 M NaCl concentration. The overlap parameter, calculated with the intrinsic vicosity data, was 3.45 g/dl in deionized water. The thermal properties of yam starch were investigated by Differential Scanning Calorimetry. Three endotherms were observed both pH solution and salt concentation. In the presence of pH 9, the onset temperature of gelatinization peak was the lowest temperature of 50.$32^{\circ}C$ and the enthalpy ($\Delta$H) was increased in this solution. The effect of salt on the thermal properties of yam starch was determined at salt concetration of 0-0.2 M NaCl. The enthalpy significantly decreased to salt concentration 0.07 M NaCl and the lowest onset temperature of this concentration was 52.$90^{\circ}C$.

• 한국전기전자재료학회논문지
• /
• 제26권5호
• /
• pp.360-366
• /
• 2013

For conventional electrical actuators, the materials are mainly made up of metals, which mean they are prone to corrosion and electrical sparking. Replacing these systems with polymer metal composite based materials can be solved both problems. Considering their excellent electromechanical property, low device fabrication cost, light weight, and good electrical conductivity, the actuator based on ionic polymer metal composite (IPMC) was fabricated using Nafion film, NaOH 0.1 molar solution, and Au electrode. IPMCs exhibit good electrostatic property which means they can in principle be used in making actuators based on electromechanical motions. The resistance measurements of Nafion film after soaking in NaOH and deionized water were demonstrated and compared each other. The result of sample soaked in NaOH showed better electrical conductivity than in deionized water. The fabricated IPMC actuator exhibits a large deformation of bending displacement of approximately 9 mm with applied low AC voltage 6.89 V at 2.84 Hz. The result of computer simulation was also very similar and shown as a bending displacement of 8.6085 mm.

• Journal of Microbiology and Biotechnology
• /
• 제17권4호
• /
• pp.616-623
• /
• 2007

The effects of initial concentration and pulsed pressurization on the inactivation of Clostridium sporogenes spores suspended in deionized water were determined during thermal processing $(TP;\;105^{\circ}C,\;0.1MPa)$ and pressure-assisted thermal processing $(PATP;\;105^{\circ}C\;and\;700MPa)$ treatments for 40 min and 5min holding times, respectively. Different inoculum levels $(10^4,\;10^6\;and\;10^8CFU/ml)$ of C. sporogenes spores suspended in deionized water were treated at $105^{\circ}C$ under 700MPa with single, double, and triple pulses. Thermally treated samples served as control. No statistical significances (p>0.05) were observed among all different inoculum levels during the thermal treatment, whereas the inactivation rates $(k_1\;and\;k_2)$ were decreased with increasing the initial concentrations of C. sporogenes spores during the PATP treatments. Double- and triple-pulsed pressurization reduced more effectively the number of C. sporogenes spores than single-pulse pressurization. The study shows that the spore clumps formed during the PATP may lead to an increase in pressure-thermal resistance, and multiple-pulsed pressurization can be more effective in inactivating bacterial spores. The results provide an interesting insight on the spore inactivation mechanisms with regard to inoculum level and pulsed pressurization.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
• /
• pp.293-296
• /
• 1998

Surface electrical conduction in insulator is most important factor to assess the insulation performances of outdoor insulating materials. In this paper, contamination performance of the widely used materials for outdoor insulator - porcelain, EPDM, Silicone rubber - were discussed by measuring properties of average leakage current and scintillation discharge pulses under artificial contamination conditions. The artificial contaminations used were deionized distilled water fog, 0.5wt% NaCl salt fog of light pollution and 2wt% NaCl salt fog of medium pollution. The average leakage current was appeared linearly with applied voltage at dry and clean surface condition. The magnitude of leakage current was almost same at different kinds of samples. In case of deionized distilled water fog, the characteristics of leakage current and applied voltage was most different to that in case of dry and clean condition. In case of salt fog pollution condition, The leakage current was increased above critical voltage. The scintillation discharges were also activated at the level. the leakage current and scintillation discharges were increased with increasing pollution degree. The resistance to pollution properties of silicone rubber appeared excellent among them.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
• /
• pp.207-210
• /
• 1998

Surface electrical conduction in insulator is most important factor to assess the insulation performances of outdoor insulating materials. In this paper, contamination performance of the widely used materials for outdoor insulator - porcelain, EPDM, Silicone rubber - were discussed by measuring properties of average leakage current and scintillation discharge pulses under artificial contamination conditions. The artificial contaminations used were deionized distilled water fog, 0.5wt% NaCl salt fog of light pollution and 2wt% NaCl salt fog of medium pollution. The average leakage current was appeared linearly with applied voltage at dry and clean surface condition. The magnitude of leakage current was almost same at different kinds of samples. In case of deionized distilled water fog, the characteristics of leakage current and applied voltage was most different to that in case of dry and clean condition. In case of salt fog pollution condition. The leakage current was increased above critical voltage. The scintillation discharges were also activated at the level the leakage current and scintillation discharges were increased with increasing pollution degree. The resistance to pollution properties of silicone rubber appeared excellent among them.

• 한국전기전자재료학회논문지
• /
• 제11권10호
• /
• pp.758-762
• /
• 1998

Electrical conduction property of insulator surface is most important factor to assess the insulation performances of outdoor insulating materials. In this paper, contamination performance of the materials to be used for outdoor insulator such as porcelain, EPDM, silicone rubber was discussed by measuring properties of average leakage current and scintillation discharge pulses under salt fog conditions. The fog was applied by nozzle in chamber and fogging fluids were deionized distilled water, 0.5wt% NaCI solution and 2wt% NaCl solution. The average leakage current showed linearly with applied voltage at dry and clean surface condition. The magnitude of leakage current was almost same at different kinds of samples. In case of deionized distilled water fog, the characteristics of leakage current and applied voltage were much different to those in case of dry and clean condition with 2wt% salt fog. In case of slat fog pollution condition, the leakage current was increased above critical voltage. the scintillation discharges were also activated at the level. The leakage current and scintillation discharges were increased with increasing pollution degree. The resistance to pollution properties of silicone rubber appeared excellent among them.

• 한국진공학회지
• /
• 제5권1호
• /
• pp.6-13
• /
• 1996

The kinetics of native oxide formation on the (Al, Ga)As and (Cd, Mn)Te have been studied by X-ray photoelectron spectroscopy(XPS) and Auger electron spectroscopy(AES). The regrowth of native oxide after 3keV Ar ion sputter etch and deionized water etch has been studied. The previous report exhibited that the native oxide on CdTe and GaAs can be removed completely by deionzied(DI) water only[1]. On the other hand, the airgrown native oxide on (Al, Ga)As become nonhomogeneous and the regrown native oxide on (Cd,Mn)Te can be partially removed.