• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.291-292
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• 2002

Using a low viscosity synthetic traction oil and a low viscosity mineral oil with nearly equal viscosity grade of ISO VG 32, the effect of kind of oil on the fatigue life of bearing steel rollers was examined. A pair of rollers finished the contact surfaces to a mirror-like condition were driven under rolling with sliding conditions of s = -3.2% and a maximum Hertzian stress in the range of $P_H=2.8GPa{\sim}4.0GPa$ was applied in point contact condition. As a result of experiments, the fatigue life with a mineral oil was longer than that with a traction oil under higher stress conditions above $P_H=3.4GPa$. Based on the numerical calculation results of the thermal EHL which simulates the present experiment, the authors discuss the reason why such a difference in the fatigue life comes out.

• Journal of Fashion Business
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• v.22 no.3
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• pp.30-38
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• 2018

Glycolic acid(GA) is well known the most effective cosmetic ingredient on the epidermal remodeling, accelerated desquamation and inhibitory effect on melanin synthesis. The various cosmetic formulations containing GA have not been reported in terms of stability. This study was to investigate the stability of three formulations(gel, cream, and ointment). The stability of obtained formulations was tested chemical and physical characteristics including the composition stability, hot-cool cycling, the variation of pH and viscosity, and the observation of color and odor. The experimental results showed that the gel and cream containing 5% GA, both formulations have proper stability in the centrifugal test, hot-cool cycling test, viscosity, pH stability and the observation of color and odor. On the other hand, the 5% GA ointment did not have stability. We concluded that the formulations of gel and cream are more suitable than ointment to use GA ingredient for developing cosmetic in terms of stability.

• Microbiology and Biotechnology Letters
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• v.23 no.6
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• pp.702-709
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• 1995

Degradation Of $\kappa $-carrageenan-based film by microorganisms screened from carrageenan source and activated sludge of a carrageenan producing factory was investigated by measuring changes of pH, viscosity, total sugar and total organic carbon (TOC) of the medium containing $\kappa $-carrageenan as a carbon source. Initially fifteen strains of microorganism were isolated from carrageenan source and activated sludge and then three organisms among them were selected based on the ability of growing in the medium including 0.3% $\kappa $-carrageenan as a sole carbon source. They were identified as Escherichia coli, Saccharomyces cerevisiae and Aspergillus niger. As indices of biodegradability Of $\kappa $-carrageenan based film, the changes of pH, viscosity, total sugar, and TOC of the carrageenan film-based medium were tested by the cultivation of single or mixed strains of the identified organisms. Mixed culture showed the highest biodegradability, which resulted in the changes of pH from 6.5 to 3.0, viscosity from 164 cps to 15.6 cps, total sugar content from 2.35 g/l to 0.53 g/l and TOC from 5721 ppm to 232 ppm after 30 days of cultivation. The biodegradability determined as the reduction rate of TOC by pure cultures of Asp. niger, E. coli, Sacch. cerevisiae and mixed culture of the three organisms were 94%, 86%, 80% and 96%, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.1001-1005
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• 2004

Rye-sensitized solar cell (DSSC) is a new class of solar cell, which consists of nanoporous TiO$_2$ electrode, dye-sensitizer, electrolyte, and counter electrode. Such cell is operated in sunlight via the principle of photosynthetic electrochemistry. In order to obtain the good dispersion of nano size TiO$_2$ particles In slurry, the pH of solvent, the sort and quantify of solvent additive and the quantity of surfactant were adjusted. As results, the lower the pH of solvent was the lower the viscosity of the slurry became. The addition of ethylene glycol and propylene glycol to dilute HNO$_3$ brought about the lowering of viscosity and the enhancement of stability in slurry. The addition of surfactant lowered the viscosity of slurry. It was possible to obtain the homogeneous and uniformly dispersed mesoporous TiO$_2$ film using the dilute HNO$_3$ solvent of pH 2 with the addition of ethylene glycol and neutral surfactant. DSSC was assembled with TiO$_2$ electrode and Pt electrode, and its photoelectric property was measured using the monochromatic wavelength in the rangee of 350∼700 nm.

• Journal of Pharmaceutical Investigation
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• v.24 no.3
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• pp.139-144
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• 1994

The effect of some formulation variables on the release rate of famotidine, a $H_2$ receptor antagonist, from cellulose matrices containing hydroxypropylcellulose (HPC) in different ratios and types was investigated. The effects of tablet shape and compression pressure on dissolution rate of famotidine were studied. And the effect of the pH of dissolution media was also studied. Increase in the ratio of polymer to drug decreased the release rate of famotidine. Increase of the polymer viscosity also decreased the release rate. The release rate of famotidine was dependent on the pH of dissolution media. The release rate of drug was not much dependent on the compression pressure but dependent on the tablet shape and/or surface area. Consequently, the release rate of famotidine can be modified by changing the HPC contents, types of polymers with different viscosity grades or using appropriate fillers.

• Microbiology and Biotechnology Letters
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• v.22 no.2
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• pp.175-181
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• 1994

A bacterial strain producing highly viscous polysaccharide(A29 POL) was isolated from soil and identified sa Bacillus sp. A29. The cultural conditions of the Bacillus sp. A29 for the polysaccharide prouction were dextrin 12%, soytone 0.2%, SnCl$_{2}$ $\cdot $2H$_{2}$O 0.02%, Na$_{2}$HPO$_{4}$ $\CDOT $12H$_{2}$O 0.36%, L-alanine 0.01%, initial pH6.8, and 30$\circ $C at pH 3 FOR 4 days. Final viscosity of the culture broth was 65, 000 cp and then the amount of produced polysaccharide was 8.3 g/l. A29 POL was composed of glucose and xylose. A29 POL showed high viscosity at low concentration(0.1%) and in the presence of the salts such as NaCl or CaCl$_{2}$. A29 POL showed high viscosity acid condition and at alkali condition and high pseudoplasticity in the presence of a NaCl or CaCl$_{2}$. It was shown that the viscosity at high temperature(80$\circ $C) was decreased but it was recovered at low temperature (20$\circ $C. A29 POL was able to from film and gel in the presence of MgSO$_{4}$ $\CDOT $7H$_{2}$O, Na$_{2}$CO$_{3}$ \CDOT $H$_{2}$O, MnSO$_{4}$ $\CDOT $ 7H$_{2}$O. A29 POL had anionic charge.

• Food Science and Preservation
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• v.17 no.4
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• pp.435-443
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• 2010

Physicochemical and functional properties of collage from skate skin (Raja Kenojei) are examined depending on pH and NaCl concentration in the medium. The solubility decreased as NaCl concentration increased but, turbidity increased as concentration of collagen increased. Oil-holding capacity and water-holding capacity were similar to other fish skin collagens. Emulsion activity, creaming stability, and viscosity were lowest at where pH levels were isoelectric point regions of collagens. However, the higher pH values at 7.0-9.0 caused increasing foam expansion, foam viscosity, and gel strength. These results indicated that collagen from skate skin could be used as a functional ingredient for food and industrial applications.

• Korean Journal of Plant Resources
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• v.11 no.1
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• pp.111-117
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• 1998

The effect of chitosan on physicochemical and organoleptic properties of Nabak kimchi was studied during fermentation at 2$0^{\circ}C$ . Viscosity of the juice of Nabak kimchi added with chitosan was lower than that of control group. The viscosity was gradually increased during storage period, especially from 5 days to ,7 days of storage. Initial pH was higher in control group than inchitosan groups. The pH of controlgroup decreased rapidly during 4 days of storage. The pH of chitosan groups was slightly increased during the first 3 days of storage and decreased thereafter. Acidity was rapidly increased from 3 to 5 days. Reducing sugar contents increased up to 3 days and decreased thereafter. Acidity was rapidly increased from 3 to 5 days. Reducing sugar contents increased upto 3 days and decreased therafter. Glutamic acid, alanine, threonine, aspartic acid, proline and valine were the major free amino acids, and as the fermentation preceeded they were increased gradually. There were signigicant differences in saltiness, sourness and aged odor in sensory evaluation of Nabak kimchi solution during fermentation at 2$0^{\circ}C$.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.297-302
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• 2005

Physicochemical properties were compared between freeze concentrated and vacuum evaporated milk through colour, brix, viscosity, freezing point and pH measurement. Brix and viscosity in each concentrated milk significantly increased due to solute concentration(p<0.05), and there was not much difference between freeze concentrated and evaporative one. Brix results were numerically modeled with the logarithmic regression: Y=-33.460+18.4513 ${\cdot}$ ln(X), $R^2=0.9798$ and this model was fairly fit to predict the solute concentration in the middle of freeze concentration process. Freezing point significantly decreased according to concentration increment(p<0.05) and there was not the significant difference between freeze concentrated and evaporated one. Whereas, in colour and pH value, there were some differences between freeze concentrated and evaporative milk. Vacuum evaporated milk expressed higher discoloration comparing to freeze concentrated one. In pH values, evaporated milk showed the significantly decreased results comparing to freeze concentrated sample, whereas the pH value of freeze concentrated sample expressed the similar value to the reference milk.

• Culinary science and hospitality research
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• v.15 no.4
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• pp.47-55
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• 2009

Gochujang sauces were prepared with 5, 10, 15, and 20% concentrated pomegranate juice(CPGJ) and analyzed with the control for quality characteristics such as proximate composition, viscosity, pH, acidity, $^{\circ}Brix$, $^{\circ}Brix$/acidity ratio, color, and sensory qualities in order to determine the optimal ratio of CPGJ in the formulation. Moisture content, crude ash, viscosity, pH, Brix/acidity decreased, while acidity, Brix increased with increasing CPGJ content. In terms of color, lightness and yellowness decreased as CPGJ content increased however, the control group had significantly(p<0.05) higher redness than the CPGJ samples. For the sensory evaluation, color was not significantly(p>0.05) different among the samples. As the CPGJ content increased, flavor, viscosity, and overall acceptability decreased, whereas sourness, acrid taste, bitterness, astringency, and off-flavor increased. In conclusion, the results indicate that the addition of 10% CPGJ to Gochujang sauce is optimal, and provides good physiological properties as well as reasonably high overall acceptability.