• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.22-26
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• 1996

In this paper, we designed 4-channel electrolyte analyzer that can measure simultaneousely the 4 electrolytes - pH, $pNa^{+}$, $pCa^{2+}$, and $pK^{+}-$ using 2-point calibration and implemented it. Developed electrolyte analyzer consists of singal processing part, actuator part and control unit for sample flow system. To implement reliable instrument, design considerations are emphasized on flow system and sample chamber that requires small sample volume and prevent air contact with sample solution. In addition to the hardware design, we developed system software which controls full measuring process. After system developed, we verified the system performance by the test measurement for pH, $pNa^{+}$, $pCa^{2+}$, and $pK^{+}$ value.

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1176-1179
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• 1995

1H NMR spectra of pyridine, α-, β-, and γ-picoline coordinated to the paramagnetic heteropolyanion [Ni3(PW9O34)2]12- (P2Ni3) are reported. NMR lines are assigned to [Ni3(ptl)n(PW9O34)2]12- (n=1, 2 or 3; ptl=pyridine-type ligand) on the basis of their [P2Ni3]/[ptl] dependence. The formation constants for γ-picoline complexes at 25 ℃ are K1=80, K2=610, and K3=190 L mol-1. The monopicoline complex has greater affinity for γ-picoline than P2Ni3. A degradation product, [Ni2(WO2)(PW9O34)2]12-, was also identified at low pH by measuring the NMR spectrum of pyridine coordinated to it. The isotropic NMR shifts come mainly from the contact interaction due to σ-electron delocalization.

• Bulletin of the Korean Chemical Society
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• v.16 no.7
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• pp.595-600
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• 1995

The kinetics of the reaction between O(3P) and C2H4 was investigated by measuring time-dependent concentrations of OH resulting from the reaction by using the LIF detection. Oxygen atoms were generated by titrating microwave discharged N2/He with NO to the chemiluminescent end point. The operating pressures in the flow reactor ranged from 5 to 15 torr and the mixtures consisted of He/O(3/P)/C2H4 in the approximate ratios from 100/1/0.1 to 100/1/1. The controlled residence time prior to the detection were estimated to be 0.8-17 ms at the reactor pressure of 7 torr. Experimentally determined profiles both in shape and magnitude were compared with the computed OH density for a specified set of experimental parameters, allowing us to arrive at a complete mechanism for the reaction of O(3P) with ethylene.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.9
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• pp.1566-1572
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• 2004

Effects of azodicarbonamide (ADA) were investigated on the rheological properties of flour dough by measuring farinogram, amylogram and extensogram based on the amount of ADA added. Quality characteristics of the bread made with the ADA added dough were also evaluated by measuring dough volume, moisture content, pH, proofed time, baking loss and textural characteristics. The farinogram showed that water absorption, stability and elasticity of the dough with ADA were higher than those without ADA. However, its absorption time and weakness decreased compared to the dough without ADA. Through the amylogram, it was found that gelatinization temperature and maximum viscosity increased, but temperature of maximum viscosity reduced in the dough with ADA. The extensogram showed that the area and resistance of the dough increased slightly but extensibility decreased drastically after fermentation, resulting in the ratio of resistance and extensibility (R/E) of the dough with ADA was lower than those without ADA. The bread prepared with the dough containing ADA after freezing up to 12 weeks showed higher pH and specific loaf volume but lower moisture content, second proof time and resistance than those without ADA.

• Journal of Korean Dental Science
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• v.11 no.1
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• pp.5-13
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• 2018

Purpose: Surface treatment with pH buffering agent has been developed to achieve higher and faster osseointegration. The aim of this study was to evaluate its influence by measuring removal torque and analyzing histological characteristics. Materials and Methods: Titanium implants with following surfaces were used in this study: sand-blasted acid-etched (SA) surface (SA group as control I group), SA surface in calcium chloride aqueous solution (CA group as control II group) and SA surface coated with pH buffering agent (pH group as test group). Removal torque test after 2 weeks and bone-to-implant contact and bone area analyses at 2 and 4 weeks were performed. Result: The rotational torque values at 2 weeks were significantly higher in pH group ($107.5{\pm}6.2Ncm$, P<0.05). The mean values of bone-to-implant contact at 2 and 4 weeks were both higher in pH group ($93.0%{\pm}6.4%$ at 2 weeks, $88.6%{\pm}5.5%$ at 4 weeks) than in SA group ($49.7%{\pm}9.7%$ at 2 weeks, $47.3%{\pm}20.1%$ at 4 weeks) and CA group ($73.7%{\pm}12.4%$ at 2 weeks, $72.5%{\pm}10.9%$ at 4 weeks) with significances (P<0.05). The means of bone area showed significantly higher numbers in pH group ($39.5%{\pm}11.3%$ at 2 weeks, $71.9%{\pm}10.9%$ at 4 weeks, P<0.05). Conclusion: Our findings demonstrated that surface modification with pH buffering agent improved early osseointegration with superior biomechanical property.

• Journal of the Korean Society of Safety
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• v.10 no.4
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• pp.47-59
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• 1995

The perchlorate, thiocyanate, and nitrate ion-selective PVC membrance electrode for measuring hazardous anion in waste water were developed by incorporating the quaternary ammonium salts as active material. Ion-selective characteristics in waste water were studied by the useful pH range, the selective coefficients to various interfering anions, and the stability of electrode potential. DBP was best as a plasticizer. The effect of the membrane thickness on the electrode characteristics was improved with decreasing the membrane thickness, but below the optimum membrane thickness the electrode exhibited an inverse trend. The electrode potential of perchlorate, thiocyanate, and nitrate electrode with TDDA, as active material, was stable within the pH range 4-11, 3-12, and 4-10 repectively. And the long-term potential stability of these electrodes were 3.0, 3.5, and 3.5 months respectively. The order of the selectivity coefficients was as shown below ; $ClO_4{^-}$ > $SCN^-$ > $I^-$ > $NO_3{^-}$ > $Br^-$ > $CN^-$ > $F^-$ > $Cl^-$ > $Ac^-$ > $H_2PO_4{^-}$, $SO_4{^-}$.

• Journal of dental hygiene science
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• v.12 no.4
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• pp.303-309
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• 2012

This study was designed to provide basic data for developing a standardized caries potentiality index to help to choose snack foods with a low score on the index by investigating adolescents' snack intakes and measuring them in total saccharinity, pH, and acidogenic potential and glucosidase activity of Streptococcus mutans (S. mutans). Total 28 snack foods were selected and measured for total saccharinity (Pocket refractometer PAL-1, ATAGO) and pH with a pH meter (Mentor, Seoul, Korea). Artificial saliva was added to each sample. The experiment group was administered with S. mutans (ATCC 3692), cultured in a constant temperature incubator at $37^{\circ}C$, and measured for pH changes over five times including after 10 minutes, 30 minutes, 1 hour, and 24 hours. Each sample of 0.3 ml was added to tubes containing sucrose, galactose, or glucose to measure the glucosidase activity of S. mutans. They were then observed for glucosidase activity with colorimetry after 24 hours of culture in a constant temperature incubator at $37^{\circ}C$. The mean pH by the acidogenic potential of S. mutans was pH 5.33. The experiment group dropped in pH more than the control group due to the increasing acidogenic potential of S. mutans by glucosidase activity, recording pH 5.27 after 10 minutes, pH 5.21 after 30 minutes, pH 5.15 after 1 hour, and pH 4.80 after 24 hours. The observation results of glucosidase activity of S. mutans with colorimetry show that most of the samples were positive in orange and yellow with glucose, sucrose, and glactose recording activity of 78.58%, 75%, and 71.42%, respectively.

• Korean Journal of Food Science and Technology
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• v.16 no.4
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• pp.423-428
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• 1984

Changes in viscosity of soymilk were evaluated as affected by solid concentration, temperature, pH and sugar addition. Soybeans were soaked, ground with boiling water, and filtered followed by boiling for 30 min for soymilk preparation. It was found that viscosity increased exponentially as solid concentration increased while the raise of temperature caused exponential decrease in it. A minimum viscosity was ovserved at pH 6.5 in the range of pH 5.0-8.0. The effects of solid concentration and pH on viscosity were reduced as the measuring temperature increased. Addition of sucrose up to 9% showed little effect on viscosity with showing a tendency of increase.

• Clinical and Experimental Reproductive Medicine
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• v.10 no.1
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• pp.39-43
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• 1983

During the period of Sep. 1981 to Feb. 1983, a program of measuring the blood gases and pH of 19 varicocele patients was taken. These patients were classified into 2 groups based upon their semen analyses; Group A consisted of 9 patients who demonstrated normal findings and group B consisted of 10 patients who demonstrated seminal stress pattern. The blood pH: $PO_2$ , and $PCO_2$ were measured in the internal spermatic vein and the radial vein of all the patients. The results obtained were as follows; 1. In Group A, no difference was detected in the value of the pH, $PO_2$ and $PCO_2$ between the internal spermatic vein and the radial vein. 2. In group B, a similar lack of difference in blood gases found between the internal spermatic vein and the radial vein. 3. The blood gases between the internal spermatic veins of Group A and B were compared. No difference was discovered between the 2 group also. It has been hypothesized that the pathogenesis of spermatogenic depression in patients with varicocele is testicular hypoxia due to low oxygen tension of the internal spermatic vein. However, our results do not bear out this proposed mechanism.

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.297-300
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• 2002

In this study, we implement the potable blood gas analyzer measuring pH, pCO$_2$and pCO$_2$of the arterial blood. The implemented system by this study is divided into hardware and software part and also the hardware portion is parted by mechanism and electronic circuit unit. The system program is composed of operating, washing, correcting and measuring program. And to correct the system, two-point calibration method is used, one-point calibration method is also added for more accuracy, and system program is coded. For verifying the implemented system, We examine to response property of each electrode. And evaluate accuracy of the system using standard reagent and was construed as statistical.