• YAKHAK HOEJI
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• v.9 no.1_2
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• pp.18-22
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• 1965

A new organic reagent, 1-isonicotinoyl-2-furfurylidene hydrazine was synthesized from isonicotinic acid hydrazide and furfural, gives precipitate with copper(II), mercury(II) and argent(I), whereas, it gives a water soluble yellow complex with iron(III). Copper complex of the reagent is soluble in EtOH MtOH, pyridine, dioxane and dimethylformamide with green yellow coloration. The complex has a maximum absorption at 385 m.$\mu$ and molar ratio of copper; reagent was estimated as 1:1 by continuous variation method, slop method and chelate titration method. Molar extinction coefficient (9600) and apparant formation constant of this complex was spectrophotometrically determined. K=1.7 * $10^{7}$ (Babko's method) K=2.1 * $10^{7}$ (Anderson's method). This reagent reacted with copper so sensitive that it would be available for determination of Cu (II).

• Proceedings of the KIEE Conference
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• 2005.07e
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• pp.73-75
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• 2005

In present measurement of moisture contents is used as one of method for estimating degradation of transformer. Most of people use Karl-Fischer titration method for detection moisture contents but this measurement is inconvenient method because we must analyze transformer oil-paper after dismounting transformer and sampling in field. Therefore we don't directly investigate them in field. In this paper we will introduce Recovery Voltage Method(RVM) that is new method for estimating measurement in field though dismounting facility. For measure of moisture contents using RVM in accordance with accelerated thermal aging we have made experimental test cell and aged at a temperature up to 140$^{\circ}C$ for 300 hours. And we have been measured at intervals of 100 hours using RVM 5462 made in fetter company.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.151-160
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• 2014

CL-SPEEK/Cs-TPA/$CeO_2$ composite membrane was prepared for polymer electrolyte membrane water electrolysis (PEMWE). In order to improve the electrochemical, mechanical, durabilities and electrocatalytic characteristics, engineering plastic of polyether ether ketone (PEEK) as polymer matrix was sulfonated and the organic-inorganic blend composite membranes was prepared by loading cesium-substituted tungstophosphoric acid (Cs-TPA) by titration method with cross-linking agent contents of 0.01mL. Ceria ($CeO_2$) was used to scavenge free radicals which attack the membrane in the PEMWE circumstance and to increase the duration of the membrane. CL-SPEEK/$Cs_{(1)}$-TPA/CeriaIn conclusion, 1% membrane showed the optimum results such as 0.119 S/cm at $80^{\circ}C$ of proton conductivity and 62MPa of tensile strength.

• Analytical Science and Technology
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• v.34 no.6
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• pp.267-274
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• 2021

Acid-base titration experiments were carried out using the same sample to obtain a direct comparison of analysis results between a new titrator and conventional Spectrator (SPT) titrators. This allowed the confirmation of an endpoint both by spectroscopic detection and by conventional titrators (automatic burette (ABT) and autotitrator (ATT)). Statistical analysis was performed on the measured values (endpoints) obtained using different titrators, to assess their differences by comparison of straightness, equivalence, ANOVA, F-test, and t-test results. The coefficients of determination, confirmed by straightness, were all >0.999. Thus, the null hypothesis that there was no statistical difference could not be rejected. The Bland-Altman analysis method was used to confirm agreement with the new experimental method. No discrepancy was found in the measured values obtained using different titrators used in this study.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.187-188
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• 2008

In this paper, we have investigated water content of semiconductive shield materials for power cables, EEA(Ethylene Ethyl Acrylate) is used polymer matrix. And filler is used CNT(Carbon Nanotube) and CB(Carbon Black). EEA, CNT and CB is favor moisture. In case of EEA, it has polyolefin resin that strong polarity combination. To research water content, experimental method used KF(Karl Fischer). KF method is Electrochemical titration based on chemical reaction. As a result, specification by KEPCO(Korea Electric Power Corporation) is lower than 800ppm. CNT and CB ratio of 80 versus 20 is best specimen that had lowest moisture content. It seem likely to increase crosslinking rate, CNT between CB.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.2
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• pp.152-158
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• 2003

Titration method is one of the widely used methods for the concentration measurement of absorbent ammonia/water. However, this method is inconvenient because the solution should be extracted for the measurement. Moreover, significant error can be introduced by the evaporation of ammonia during the sampling and measuring procedure. In this study a reliable in-line concentration measurement method was proposed. To prove the validity of the concept, a measuring apparatus was designed, built, and tested with water. It is found that the location of flow inlet and exit is important in the measurement accuracy. The flow inlet and exit located in the middle of the test cell showed the best result. By the error analysis, it is expected that the ammonia concentration can be measured within the error of $\pm$0.18% assuming the error of 0.1 K in temperature measurement and 0.1 g in weight measurement.

• International Journal of Safety
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• v.9 no.1
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• pp.43-46
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• 2010

In the recycle process of organic solvent, the atmospheric oxygen can cause autoxidation and product peroxide. The time-saving method to evaluate the hazards has been required. In this study, oxygen pressure monitoring experiment was proposed as a new method to evaluate autoxidative resistances of solvents. Some of organic solvents were pressurized by oxygen and kept under isothermal condition. At the same time, the pressure in the vessel tracked. Iodometrical titration, thermal analysis and spectroscopic analysis were performed to measure peroxide concentration, the heat of reaction and chemical bonding change. From the results that THF has larger oxygen consumption rate than CPME, it is considered that autoxidative resistance of THF is lower than that of CPME. This method enables to obtain results in shorter time than other methods. These experimental results were consistent with the previous research with longer test durations [1-2].

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.5
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• pp.275-278
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• 2003

Antioxidative activity is an important factor in inhibiting oxidative stress. The usual methods for determining antioxidative activity are time-consuming and cumbersome. They are also indirect processes that use biological material such as brain or liver microsome. This study therefore proposed a new method. Redoxpotential was determined using galvanic cell with or without the addition of various antioxidants or herbal extracts in zinc sulfate solution. The result was compared with the results from the TBA method and the peroxide value from sodium thiosulfate titration. All methods showed significant and dose-dependent enhancement of antioxidative activity by adding ascorbic acid, quercetin, ginseng, or gingko biloba extract. The result of redox potential using galvanic cell showed the smallest standard deviation and took the shortest time among the three methods. Therefore, the antioxidative potential of chemical substances and herbal extracts can be determined simply, directly and accurately in a short period of time using galvanic cell.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.186-193
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• 1996

Several chitosan beads were prepared by W/O emulsion and capillary extrusion methods. The surface structures were observed through SEM pictures, the surface areas were determined by BET method, the available amine contents were measured by picric acid titration method, and the results were correlated each other. The beads from W/O emulsion method were smaller in size but had higher hardness, surface area, and available amine contents than the ones from capillary extrusion method. Moreover, the surface area, available amine contents, apparent density and the hardness showed large differences according to the drying processes. As compared between the solvent dehydration and the freeze drying technique in W/O emulsion method, the former showed higher surface area, higher available amine contents and hardness than the latter. SEM pictures revealed that in case of solvent dehydration method, very small pores existed, whereas in case of freeze drying method, cell-like pores existed on the surface. The results of picric acid titration showed that the beads dried by solvent dehydration method were 10 times higher in amine contents than those from freeze drying method, and the amount of amine contents were increased as the surface area was increased. After fluorescamine was reacted with chitosan beads, the fluorescence labeled beads were observed through fluorescence microscope. The results showed that most of primary amine existed on the surface of beads and pores.

• Archives of Pharmacal Research
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• v.12 no.2
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• pp.114-118
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• 1989

The effects of intraperitoneal injection of cephradine in a dose of 75 mg/kg and netilmicin in dose of 50 mg/kg and their combination on creatinine and urea serum levels of rabbits were studied as well as the antipseudomonal activity against three multiresistant clinicial isolates. The antibacterial activity was investigated by two methods: Checkerboard titration method and time-kill studies. Finally, the antibacterial activity of the sera obtained from the rabbits receiving the used drugs in the previous regimen was studied using time-kill study method against Pseudomonas aeruginosa isolates. Results obtained from this study indicated that both creatinine and urea serum levels of the rabbits receiving both drugs were not significantly different from those of the rabbits receiving either cephradine or netilmicin alone. At the same time the in vitro antibactrial activity (either of the prepared solutions of the used drugs and their combination or of the sera obtained from the rabbits receiving these drugs as mentioned before) showed a synergistic effect against the tested strains of Pseudomonas aeruginosa