• YAKHAK HOEJI
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• v.39 no.1
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• pp.61-67
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• 1995

PVC membrane electrodes based on the lipophilic neutral carrier, dibenzo-18-crown-6, cyclic oligomers of teit-butylphenol-formaidehyde condensates, calix[4]arenes as the active sensors for verapamil have been prepared and tested in a variety of plasticizers. At pH 5.0, the electrode exhibits a Nernstian response in the range of 10$^{-2}$~5$\times$10$^{-5}$ M verapamil with a slope of 49.1$\pm$0.5mV per concentration decade. The electrode constructed in this work can be used continuously for at least 1 month before any damage to the membrane occurs. And the analyses of the local anesthetic amine, which are good to select a specific compound in a mixed solution, were also accomplished by using of another neutral carrier, a DB18C6, for comparing with calix[4]arene.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.10a
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• pp.75-75
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• 2006

• Korean Journal of Veterinary Research
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• v.32 no.4
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• pp.463-479
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• 1992

The morphological findings of the parotid, mandibualr and sublingual salivary glands of the Korean native goat have been investigated by the histological and histochemical observation using the light microscope. Tissues were fixed with 10% neutral buffered formalin and Bouin's solution, and embedded in paraffin. The tissue sections were stained with hematoxylin and eosin, Heidenhain's azocarmine-aniline blue, alcian blue, toluidine blue, periodic acid Schiff, aldehyde fuchsin, alcian blue-periodic acid Schiff and aldehyde fuchsin-alcian blue. Some sections were stained with the alcian blue after each teatment of diastase digestion, methylation, methylation-saponification, and neuraminidase digestion. The results were as follows ; 1. The major salivary glands were compound. tubuloacinar glands, and the parenchyma was composed of acini, intercalated ducts, striated ducts and excretory ducts. 2. The acini were composed of serous cells in the parotid gland, and mucous cells, serous cells and seous demilunes in the mandibular gland. The acini of the sublingual glands were composed of mucous cells and serous demilunes. 3. In histochemistry, the serous cells of the parotid gland contained neutral mucin and enzyme-liable silaic acid. 4. The serous cells and demilunes of the mandibular gland contained neutral mucin and enzyme-liable sialic acid, and the mueous cells contained sulfated mucin, enzyme liable sialic acid and neutral mucin 5. In the sublingual gland, the mucous cells contained sulfated mucin, enzyme-resistant sialic acid and neutral mucin, and the serous demilunes contained neutral mucin and enzyme-resistant sialic acid.

• Korean Journal of Materials Research
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• v.32 no.9
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• pp.361-368
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• 2022

The overall process, from the pre-treatment of aluminum substrates to the eco-friendly neutral electroless Ni-P plating process, was observed, compared, and analysed. To remove the surface oxide layer on the aluminum substrate and aid Ni-P plating, a zincation process was carried out. After the second zincation treatment, it was confirmed that a mostly uniform Zn layer was formed and the surface oxide of aluminum was also removed. The Ni-P electroless plating films were formed on the secondary zincated aluminum substrate using electroless plating solutions of pH 4.5 and neutral pH 7.0, respectively, while changing the plating bath temperature. When a neutral pH7.0 electroless solution was used, the Ni-P plating layer was uniformly formed even at the plating bath temperature of 50 ℃, and the plating speed was remarkably increased as the bath temperature was increased. On the other hand, when a pH 4.5 Ni-P electroless solution was used, a Ni-P plating film was not formed at a plating bath temperature of 50 ℃, and the plating speed was very slow compared to pH 7.0, although plating speed increased with increasing bath temperature. In the P contents, the P concentration of the neutral pH 7.0 Ni-P electroless plating layer was reduced by ~ 42.3 % compared to pH 4.5. Structurally, all of the Ni-P electroless plating layers formed in the pH 4.5 solution and the neutral (pH 7.0) solution had an amorphous crystal structure, as a Ni-P compound, regardless of the plating bath temperature.

• KSBB Journal
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• v.4 no.1
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• pp.8-10
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• 1989

Mutagenic characteristics deactivation of 7, 12-dimethylbenz(a)anthraracene was studied in a nonacclimated sandy loam soil at low and neutral pH soil conditions. Soil extracts containing transformation products were separated into three fractions based on HPLC retention time(polarity). Highly polar transformation products of 7, 12-dimethylbenz(a)anthracene demonstrated a negative mutagenic response with the Ames mutagenicity assay, strain TA-100, for both low and neutral pH soils. Moderate and low polar fractions, however, induced mutagenicity for both soil samples with mutagenic ratios similar to those of the parent compound.

• Bulletin of the Korean Chemical Society
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• v.11 no.1
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• pp.54-58
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• 1990

Acid-base equilibria and spectroscopic properties of diazepam and chlorodiazepoxide were investigated in sodium dodecyl sulfate (SDS) micellar solutions as functions of pH. The results were compared with the behaviors in homogeneous aqueous media. The presence of SDS increased the $pK_a$ of chlorodiazepoxide to 6.3 from 4.7, while it has little effect on the $pK_a$ of diazepam. The acidic protonated form of diazepam was moderately fluorescent when the solution was excited at 350 nm, and emissnion intensity of the species was enhanced about 5 fold by the presence of SDS. On the other hand, the acidic solution of chlorodiazepoxide was non-fluorescent, but the neutral solution of the compound was fluorescent upon excitation at 350 nm. The emission peak of the neutral chlorodiazepoxide shifted to shorter wavelength region without significant change in the emission intensity upon the addition of SDS. Procedures for assay of the individual drugs from their mixture by the use of SDS micelle were discussed.

• Journal of Korean Society on Water Environment
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• v.29 no.2
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• pp.176-183
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• 2013

The variation of the stable region of arsenic compounds in aqueous environment with temperature has been investigated by constructing the Pourbaix diagram of arsenic at different temperatures. The standard potential corresponding to the boundary between arsenic compounds with different charge valence was estimated to be decreased with temperature, which means the stability of arsenic compound with +5 charge valence increases. The distribution diagram of the most highly oxidized arsenic compound showed that arsenic acid is formed at higher pH and arsenate is generated at lower pH as temperature rises. The aquatic toxicity due to arsenic compounds was considered to be decreased with temperature in the neutral pH condition based on the $LD_T$ value defined in this study.

• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.29-33
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• 1996

Mono-, or di-substituted chlorodicyanovinyl benzene compound was reacted with an excess amount of ethylenediamine to give corresponding imidazoline product with high reaction yield. This reaction occurs by stable imidazoline ring-forming process through nucleophilic attack of terminal amine on the enaminonitrile adduct, the reaction intermediate, toward electropositive enamine carbon, which is accompanied by the release of neutral malononitrile moiety. The similar reaction with 1,2-phenylenediamine produced stable enaminonitrile-amine adduct at lower temperature which could be cyclized intramolecularly to thermally stable benzimidazole at elevated temperature in solution or in solid state. From the difunctional compound of both reactants, poly(enaminonitrile-amine) could be prepared as a new soluble precursor polymer for well-known polybenzimidazole (PBI). The thermal cyclization reaction accompanying the release of malononitrile molecules was studied using thermalanalysis and infrared spectroscopy.

• Korean Journal of Food Science and Technology
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• v.10 no.2
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• pp.119-123
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• 1978

Lipids, extracted with chloroform-methanol (2:1 by vol.) and purified, from nut and leaf of Ginkgo biloba were identified and quantitatived by column, thin layer and gas liquid chromatography. The results were summarized as follow: 1) The total content of purified lipids in the nut and leaf on the fresh weight basis were 1.32% and 2.24%, respectively. 2) The lipid fractions in the nut obtained by silicic acid colum chromatography were found to be composed of about 89% neutral lipids and about 10% compound lipids, and in the leaf were found to be composed of about 28% neutral lipids and about 72% compound lipids. 3) Among the neutral lipid fractions, triglycerides (86.2%) were the major component in the nut, but esterified sterols (53.3%) were the major component in the leaf. 4) The main fatty acids of the total lipids were oleic(37.5%) and linoleic acid(44.5%) in the nut, but linolenic(45.2%) and palmitic acid (25.1%) were main fatty acids in the leaf. The patterns of fatty acid composition of the neutral lipid fractions in the nut and leaf were found to be similar, and oleic, linoleic and palmitic acid were the predominant. A large amount of oleic and linoleic acid in the glycolipid fractions was found in the nut compared with those in the leaf, but linolenic acid content in the leaf was significantly higher than in the nut. And patterns of fatty acid composition of the phospholipid fractions in the nut and leaf were found to be similar to that of glycolipid fractions.

• Journal of Environmental Science International
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• v.22 no.9
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• pp.1153-1160
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• 2013

While a range of natural organic matter (NOM) types can generate high levels of disinfection by-products (DBPs) after chlorination, there is little understanding of which specific compounds act as precursors. Use of eight model compounds allows linking of explicit properties to treatability and DBP formation potential (DBPFP). The removal of model compounds by various treatment processes and their haloacetic acid formation potential (HAAFP) before and after treatment were recorded. The model compounds comprised a range of hydrophobic (HPO) and hydrophilic (HPI) neutral and anionic compounds. On the treatment processes, an ozone oxidation process was moderate for control of model compounds, while the HPO-neutral compound was most treatable with activated carbon process. Biodegradation was successful in removing amino acids, while coagulation and ion exchange process had little effect on neutral molecules. Although compared with the HPO compounds the HPI compounds had low HAAFP the ozone oxidation and biodegradation were capable of increasing their HAAFP. In situations where neutral or HPI molecules have high DBPFP additional treatments may be required to remove recalcitrant NOM and control DBPs.