• 한국잠사곤충학회지
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• 제31권2호
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• pp.121-126
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• 1989

1. 제사용수의 pH가 총탄산이 낮은 용수에서는 견층 Sericin 용해에 미치는 영향이 적었지만, 총탄산이 높은 용수에서는 견층 Sericin 용해에 미치는 영향이 컸다. 2. 총탄산이 낮은 용수에서는 견층처리전후의 pH변화가 컸지만 총탄산이 높은 용수에서는 그 변화가 적었다. 3. 무탄산 증류수로 표준경도용액을 만들어 견층을 처리한 결과 경도가 높고 낮은데 대한 Sericin 용액관계는 없었다.

• 약학회지
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• 제15권1호
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• pp.24-31
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• 1971

Optimum reaction conditions for the preparation of extra-light magnesium carbonate from bittern by the reaction with sodium carbonate solution was found to be as follows: reaction temperature 33.deg. molar ratio(Mg$^{+2}/CO$^{2-}_{3}$)0.8, reaction time 14 minutes, drying temperature 99.deg. and bittern concentration 17%. While Korean pharmacopeia regulates the bulkiness above 12 mililiters per gm., our experimental result shows above 45 mililiters. Electron microscopic shapes were compared with products prepared under various reaction conditions, and it was found that there exists lighter the powder the more pillar crystalline, the heavier the powder the more amorphous and the intermediate was mixture of them.

• Korean Chemical Engineering Research
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• 제46권6호
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• pp.1107-1112
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• 2008

침강성 탄산칼슘의 제조를 위해 액체-액체 상태에서의 결정화 실험을 실행하였다. 탄산칼슘 결정을 만들기 위한 방법 중 조작이 간단하며 다양한 탄산칼슘 결정을 얻을 수 있는 염화칼슘과 탄산나트륨의 반응법을 선택하였다. 반응 시간, 용질의 농도, pH, 유기 첨가제를 변경하여 탄산칼슘을 합성하였다. 유기 성분을 가진 탄산칼슘을 합성하기 위해 아미노산이 복합되어 있는 silk fibroin을 첨가하였고, silk fibroin이 탄산칼슘의 결정화에 미치는 영향에 대해 초점을 맞추어 실험을 수행하였다. 여러 탄산칼슘 결정을 분석하기 위해 FE-SEM, XRD, 그리고 FT-IR을 사용하였다. 반응 시간, pH가 탄산칼슘 결정 형태에 큰 영향을 줌을 관찰하였다. Silk fibroin이 결정형태 vaterite의 형성을 저해하고 calcite의 형성에 효율적인 첨가제로 작용하는 것을 발견하였다.

• 한국세라믹학회지
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• 제18권2호
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• pp.105-111
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• 1981

The iron precipitates were prepared by adding sodium carbonate solution to ferrous chloride and ferric chloride solutions to pH=9 and pH=4.5, respectively. The thermal reaction of the iron precipitates was investigated by means of TGA, DTA and X-ray diffraction. In the former the crystallization of $\alpha$-$Fe_2O_3$ begins at about 35$0^{\circ}C$, while in the latter at about 30$0^{\circ}C$, during the calclnation in air. In the iron precipitate from ferrous chloride solution, the activation energy for the crystallite-growth or $\alpha$-TEX>$Fe_2O_3$ in air is about 7.6$\times$104J/mole between 800 and 100$0^{\circ}C$. As the result of X-ray diffration for the reduction product of hematite, it was found that maghemite, magnetite and wustite are formed and that hematite is transformed to magnetite through maghemite.

• 대한가정학회지
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• 제32권1호
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• pp.229-238
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• 1994

The purpose of this study was to investigate the objectification of coloring matter abstraction of the way to natural dye by cathamus flower. Watersoluble carthamin in the dyeing cathamus flower was removed for the fastness of dyeing and only insoluble carthamon was abstracted which came by solvent such as Sodium hydroxide(NaOH) Potassium hydroxide(KOH) Sodium carbonate(Na2CO3)and Potassi-um carbonate(K2CO3) Carthamon made abstract essence from a carthamus flower out of the pH6, pH7, pH9, pH11, solvent and by using a UV/VIS Spectra according to the change of pH. Silk dyes with solution abstract carthamon and it was treated by 5 kinds of mordant. The table of surface-colors was measured by the number of dyeing the color of silk dyed and by the kind of mordant which treated with and the dyeing was evaluated by measuring Color Fastness to Light and Washing.

• 한국염색가공학회지
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• 제18권6호
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• pp.25-30
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• 2006

Degumming is an essential process to improve the luster and smoothness of the silk filament. Silk varieties were degummed using different methods. A number of methods, from pad-steam to specific alkaline are being used for this propose. In this paper an attempt to compare the efficiencies of different degumming processes has been made. from the results, it may be observed that when silk fabrics were pad-steam, the degree of degumming, as assessed by weight loss. When the pad-steam degumming was carried out at different pHs, adjusted using alkalies, it was observed that at higher pH the weight loss is high. Pad-steam degumming as well as star degumming was found to be superior with minimum damage to the substrate. Among the alkalis used, the sodium carbonate gives the best results, since the weight loss is almost maximum with lower strength loss by over degumming. It is also efficient from the point of view of conservation of heat energy and time as against the comparable star degumming.

• 한국응용과학기술학회지
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• 제25권1호
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• pp.83-90
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• 2008

The core-shell latex particles were prepared by sequential emulsion polymerization using alkyl methacrylate as a shell monomer and potassium persulfate (KPS) as an initiator. We study the effects of core-shell structure of calcium carbonate/alkyl methacrlyate in the presence of an anionic surfactant sodium lauryl sulfate (SLS) and polyoxyethylene alkyl ether sulfate (EU-S133D)). The structure of core-shell polymer were investigated by measuring to the thermal decomposition of polymer composite using thermogravimetric analyzer and morphology of latex by transmission electron microscope (TEM).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.177-178
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• 2006

We investigate anisotropic texturing method for crystalline silicon solar cells with sodium carbonate solutions. Texturing temperature have a large effect on the density of pyramid. The dependence of the surface reflectance on solution temperature and the etching time was investigated. The surface morphology was observed by scanning electron microscope and the surface reflectance was evaluated. The reflection from the silicon surface in the wavelength range 400 to 1000nm is reduced to about 12%.

• 한국가정과학회지
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• 제6권1호
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• pp.27-34
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• 2003

We investigated the bacterial and chemical retting conditions of ramie grown in Hansan. Bacterial retting was done in troughs at a temperature of 30${\pm}$2$^{\circ}C$ for 1, 2, 3, 4, 5, 6 and 10 days. Chemical retting(CR) was done at the different conditions using sodium silicate (Na$_2$SiO$_3$), sodium carbonate(Na$_2$CO$_3$) and sodium hydroxide(NaOH) as alkali solutions. The retting solution was boiled during 1. 2, 4 and 6 hours respectively at the different concentration(0.5, 2.0, 4.0, 6.0. 8.0 %) with decorticated ramie stems submerged in it. The treated ramie was then rinsing with running tap water thoroughly, which was further soaker in 0.5% acetic acid (v/v) solution for three minutes and washed thoroughly with distilled water. Finally ramie was dried for 2 hours in vacuum oven at 100 $^{\circ}C$. To know change of ramie fiber characteristics retted at the different conditions, weight loss, fiber bundle strength were tested and color, texture, luster etc. were also sensually evaluated. The results were as follows. $.$ Weight loss of ramie retted in each alkali solutions were about 10%, 20% and 30% in sodium silicate, sodium carbonate and sodium hydroxide, respectively. $.$ Chemical retting was faster than bacterial retting, but the color of chemically retted ramies were worse than that of bacterially retted ramies. $.$ The combination of bacterial and chemical processing showed some merits. A combination of either 2 or 3 days of bacterial and then chemical retting might provide the best quality ramie. $.$ Ramie fiber became cottonized ramie when retted in 8% NaOH solution for 6-8hours.

• 한국표면공학회지
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• 제36권3호
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• pp.251-255
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• 2003

With increasing environmental demands in surface treatment of steel sheets, the passivation layers containing hexavalent chromium $(Cr^{+6})$ are being replaced by non-chromium or trivalent chromium compounds. After review on the various types of inorganic compounds, the zirconates was chosen as the candidate for alternative to sodium dichromate in the aspect of its barrier properties with excellent adhesion to organics. The ammonium zirconium carbonate (AZC) and sodium hexafluorozirconate (SFZ) could be reach $70-80\%$ level of CDC (cathodic dichromate) treatment by their single applications. But high porosity in the AZC layer and poor electrical conductivity of SFZ solution limit the single application of zirconate. Mixed composition of zirconates to compensate their inferiorities or incorporation of organic compounds to seal the porosity seems to be inevitable to match up the target level of Cr-free passivation of tinplate.