• Journal of the korean academy of Pediatric Dentistry
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• v.25 no.1
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• pp.93-102
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• 1998

Infant formula in nursing bottle, with inappropriate feeding habits, is major factor associated with the development of nursing caries. Although each infant formula has different carbohydrate and protein composition, studies comparing cariogenic potential of many Korean-branded infant formulas are deficient. In addition, it is on the point of being difficult to evaluate the cariogenecity of milk due to development of many infant formulas. In this study, to evaluate the cariogenic potential of many infant formulas, after oral rinse with six Korean-branded infant formulas(three milk based formulas, one soy based formula and two specific formulas for infants with allergy to milk protein and with lactose intolerance) for ten adult volunteers(eight males and two females), plaque pH change was measured with In vivo/In vitro combination technique and results were as follows. 1. All six different kinds of Korean-branded commercial infant formulas dropped the plaque pH significantly(p<0.05) and at an hour after rinse, plaque pH was not recovered in most of subjects. 2. Soy based infant formula and casein-hydrolyzated infant formula containing no casein dropped the plaque pH significantly more than milk based infant formula containing casein (p<0.05). 3. In the milk protein of infant formulas, casein had more effect on buffering the pH change of the infant formula than whey protein and casein-hydrolyzated infant formula had a reduced effect of casein. 4. In infant formulas with similar protein composition, infant formula containing sucrose dropped plaque pH more than infant formula containing lactose, but there was no significant difference (p>0.05).

• Communications of the Korean Mathematical Society
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• v.30 no.1
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• pp.7-21
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• 2015

We give the characterization of H$\ddot{o}$lder differentiability points and non-differentiability points of the Riesz-N$\acute{a}$gy-Tak$\acute{a}$cs (RNT) singular function ${\Psi}_{a,p}$ satisfying ${\Psi}_{a,p}(a)=p$. It generalizes recent multifractal and metric number theoretical results associated with the RNT function. Besides, we classify the singular functions using the singularity order deduced from the H$\ddot{o}$lder derivative giving the information that a strictly increasing smooth function having a positive derivative Lebesgue almost everywhere has the singularity order 1 and the RNT function ${\Psi}_{a,p}$ has the singularity order $g(a,p)=\frac{a{\log}p+(1-a){\log}(1-p)}{a{\log}a+(1-a){\log}(1-a)}{\geq}1$.

• Korean Journal of Microbiology
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• v.17 no.1
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• pp.42-48
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• 1979

Cellulases were isolated from both healthyl(PC) and virus0infected penicillum chrysogenum(PCV) in the wheat bean culture, and some properties of the enzymes were studied. 1) At $37^{\circ}C$, pH 6, 4 and 6day's culture the maximal enzyme yield was obtained in both PC and PCV. 2) The optimum temperature for the PC cellulase was at $50^{\circ}C$, and that for the PCV enzyme was the same. 3) The optimum pH for the PC enzyme was at 5.0, whereas the PCV enzyme was at 6.0, indicating that they are isozymes. 4) When Na-CMC was used as a substrate, PC enzyme was twice as high as the activity of PCV enzyme.

• Journal of the Korean Chemical Society
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• v.40 no.12
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• pp.733-740
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• 1996

The rate constants for the hydrolysis of 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide(AMQD) were determined by ultraviolet visible spectrophotometer in water at $25^{\circ}C.$ The rate equation which could be applied over wide pH ranges were obtained. On the basis of pH-rate profile, Bronsted plot, hydrolysis product analysis, general base catalysis and substituent effect, the plausible hydrolysis mechanism was proposed: Below pH 3.00, the hydrolysis reaction was proceeded by the attack of water to 4'-position of quinonoid after protonation at nitrogen of acridinyl and between pH 3.00 and 9.00, the addition of water and hydroxide occurred competitively. However, above pH 9.00, the rate constants were dependent upon only the concentration of hydroxide ion.

• Journal of the Korean Chemical Society
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• v.40 no.9
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• pp.599-606
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• 1996

The effects of chemical species in groundwater on the solubility of the uranyl hydrolysis precipitates formed at pH 6.4 and 9.7 were investigated. Based on the chemical composition of the groundwater, the synthetic groundwater was prepared. The colloid-free (separated) groundwater was also prepared by removal of both organic and inorganic colloids from the sampled groundwater. Solubilities of precipitates formed in the hydrolysis of uranyl ion in groundwater, separated groundwater, synthetic groundwater and 0.1 M NaCl solution were measured over neutral to alkaline pH range, and especially, the effect of the anions and cations found in groundwater on the solubility was investigated. Solubility in groundwater was approximately two orders of magnitude greater than that in 0.1 M NaCl solution. Soubililties of uranyl hydrolysis precipitates formed at pH 9.7 and 6.4 were compared in groundwater and synthetic groundwater. Solubilities of the precipitates formed at different pH were found to be in the same order of magnitude in groundwater and synthetic groundwater, however the uranyl hydolysis precipitates formed at higher pH values showed a tendency of higher solubility.

• Applied Biological Chemistry
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• v.9
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• pp.91-96
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• 1968

1. Two strains of Aspergilli producing acid resistant amylase were isolated from air. The strain $U^{-1}$ and $U^{-2}$ were similar to Asp. usamii tan type mutant in the morphological characteristics. 2. The influence of cultural pH for production of amylase were investigated in the suface culture, it was different each other in the cultural optimum initial pH. The activity of acid resistant amylase produced by strain $U^{-1}$ was higher than that of strain $U^{-2}$. The acid resistance was increased by culturing in lower pH. 3. The lower initial pH ($U^{-1}$ pH 4.0, $U^{-2}$ pH 2.0) was better than neutral (pH 6.0) for the production of amylase and growth of them. The effect of low initial pH for the production of amylase was not to accelerate but caused by change of pH in the cultural process, in the range of this experiment.

• Journal of Korean Society of Steel Construction
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• v.17 no.3 s.76
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• pp.347-356
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• 2005

Recently, pre-engineering building (P.E.B.) systematic frames are increasingly being used in steel factory buildings, but almost of the related techniques are dependent on the engineering program (e.g, MBS, LTI), which is usually imported from other countries. These are designed under the AISC-ASD because at present there is no Korean design code for P.E.B. frames. Also, there are few studies onbehaviour and we need to develop the element techniques by using H-shaped components.In particular, there is a tendency towards overestimated design because column-rafter connections have been designed with extended end plate type joint, which is treated asrigid joint,so structural examinations are needed. Therefore, this study represents a basic step in ascertaining the application of P.E.B. systematic frames by using H-shaped column-rafter connectionwith flush type end plate. Its structural performance is compared with that of existing extended type joint using a structural performance test. The structural behaviour of specimen was understood qualitatively and the possibility of application (e.g, design aid charts) of semi-connection (flush type) with H-shaped column-rafter was determined.

• Applied Biological Chemistry
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• v.29 no.2
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• pp.212-218
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• 1986

Proteins in Korean rapeseeds, as in many other plantseeds, are usually bound to phytate molecules. These phytate-bound proteins are of little value as foodstuffs because of their poor solubility in digestive systems. Therefore it is necessary to remove phytates from proteins in order to convert these proteins io a useful foodstuff. In the work, an efficient procedure for removal of phytates from defatted Korean rapeseed was found. The influence of pH on the solubility of protein and phytate of rapeseed flour showed that the former was the lowest at pH 5.0 and began to increase as pH further raised. Meanwhile, the latter was the highest at pH 6.0, however, it was decreased abruptly at alkaline pH, especially to content of 1.3% at pH 11.5. The solubility cf protein was relatively high in NaCl aqueous solution at $pH\;6.0{\sim}8.0$, and did not male any noticeable difference depending on NaCl concentration. On the other hand, the solubility of phytate was high at pH of below 6.0 showing an abrupt decrease at pH of above 6.0. The solubility of protein in $CaCl_2$ aqueous solution was highest at $pH\;6.0{\sim}8.0$, however, there was no significant change at the whole range of tested pH of the solution. A maximum solubility of phytate was shown at $pH\;3.0{\sim}4.0$. And it was decreased abruptly at a higher pH of the above range and also decreased at a lower pH with higher $CaCl_2$ concentration. The solubility of phytate in $Na_2SO_3$ aqueous solution was highest at $pH\;5.0{\sim}8.0$. As the concentration goes up the maximum value of solubility was found to move to higher pHs. Depending on the concentration of $Na_2SO_3$, the decreasing pattern was changed in an alkaline solution. The solubility of phytate in the solution containing low concentration of $Ca^{2+}$ ion was low in all treatments at pH of above 7.0 and showed the maximum value at low pH as $Ca^{2+}$ ion concentration increases. The solubility of protein at pH 11.5 showed the highest value in $1mM\;Ca^{2+}$ ion solution.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.91-97
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• 1981

A thermophilic soil isolate Bacillus sp. Y-127 was selected for the production of thermostable amylase. The strain was used for the enzyme production and the thermostable amylase was characterized. The optimum cultural conditions for the enzyme production were 6$0^{\circ}C$ at pH 7.0 for 32 hours using a mineral medium containing 2% soluble starch and 0.2% yeast extract. The extra-cellular enzyme was purified about 123-folds with about 6% recovery. The purified enzyme was stable at pH between 4.0 and 7.0, and temperature up to 6$0^{\circ}C$.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.42-54
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• 1989

This study was carried out to investigate the phenomena of acid precipitation. The pH value, electro conductivity and major anions (sulfate, nitrate and chloride) were measured by automatic acid rain monitor and ion chromatography at 5 points in Seoul area from Jan. to Dec. 1988. 1. The acidity of rainfall was in order winter (4.31) spring (4.77) fall (4.94) summer (5.31). Rainfall with a pH of less than 5.6 was appeared 83.2 percent. 2. The range of the highest appearence frequency rate both at Hannam-dong and Songsu-dong was from pH 4.6 to 5.0 and appeared 30.7 percent and 38.3 percent respectively, Bang-i-dong was 36.3 percent in the ranged from pH 4.1 to 4.5 and Guro and Ssangmun-dong were 26 percent and 30.3 percent in the ranged from pH 5.1 to 5.5 respectively. 3. The sulfate and nitrate ion concentration in earlier rainwater ranged from 0.1 ppm to 50.2 ppm and from 0.01 ppm to 15.8 respectively. The earlier rainwaters were generally more acidic than the after rainwaters. 4. The order of the major anion concentration in rainwater was $SO_4^{2-} > Cl^- > NO_3^-$ and the acidity of it was more effective by sulfate ion than others. The correlation between pH value and anions concentration was shown positive correlationship at Guro-dong and Bang-i-dong and negative correlation at Hannam-dong but not at the other sites.