• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.669-672
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• 2001

Pseudo-first-order rate constants have been measured spectrophotometrically for the title reactions. The plot of kobs vs the concentration of alkali metal ethoxides is linear for the reactions performed in the presence of complexing age nt, 18-crown-6 ether, but curved upwardly for the corresponding reactions performed in the absence of the complexing agent, indicating that the alkali metal ions studied in this study behave as a catalyst. The catalytic effect was found to increase in the order Li+ << K+ ${\leq}$ Na+. Second-order rate constants were determined for the reactions with dissociated free ethoxide (kEtO-) and with ion paired alkali metal ethoxides (kEtO-M+ ) from ion pairing treatments. The magnitude of catalytic effect (kEtO-M+/kEtO-) was found to be 2.3, 9.5 and 8.7 for the reaction of 8-(5-nitroquinolyl) 2-furoate, while 1.4, 3.6 and 4.2 for that of 4-nitrophenyl 2-furoate, indicating that the catalytic effect is larger in the reaction of the former substrate than in that of the latter one. The larger catalytic effect was attributed to two possible complexing sites with alkali metal ions in the former substrate.

• Journal of Ocean Engineering and Technology
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• v.31 no.3
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• pp.248-255
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• 2017

Many rivers and seas have been affected by environmental contamination. Therefore, city water supplies often require a high-degree purification treatment to provide safe drinking water. However, in order to achieve a high-degree purification treatment, a large amount of chlorine has to be added to sterilize city drinking water. The added chlorine reacts chemically with water and forms hypochlorous and chlorine ions. The hypochlorous ionizes with hypochlorous ions and hydrogen ions. As a result, the city water contains a large amount of chlorine ion. As such, when city water is used with domestic boilers, many kinds of heat exchangers, and the engines of vehicle and ships, there are often corrosion problems. In this study, alkali water was electrochemically made by electrolysis of city water, and corrosion properties between alkali and city water were investigated with an electrochemical method. Most of the chlorine ions are thought to not be contained in the alkali water because the alkali water is created in the cathodic chamber with an electrolysis process. In other words, the chlorine ion can be mostly removed by its migration from a cathodic chamber to an anodic chamber. Moreover, the alkali water also contains a large amount of hydroxide ion. The alkali water indicated relatively good corrosion resistance compared to the city water and the city water exhibited a local corrosion pattern due to the chlorine ion created by a high-degree purification treatment. In contrast, the alkali water showed a general corrosion pattern. Consequently, alkali water can be used with cooling water to inhibit local corrosion by chlorine ions in domestic boilers, various heat exchangers and the engine of ships and for structural steel in a marine structure.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.1
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• pp.31-37
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• 1993

To analyze and classify the varietal variation of alkali digestibility in detail, which is closely connected with the gelatinization temperature and physical characteristics of cooked rice, the patterns of alkali decomposition changed along the alkali concentration were investigated for thirty three Korean leading rice cultivars and new breeding lines(japonica : 25, Tongil-type:8) including five glutinous rice. Principal component analysis was used to condense the information and to classify rice materials according to decomposed reaction pattern at several levels of potassium hydroxide(KOH) concentration. Thirty three rice varieties were classified largely into four groups by the distribution on the plane of upper two principal component scores which contained above 92% of total informations. Group I was consisted of one variety, Dobongbyeo, which owned almost same strong resistance to alkali digestion at the range of 0.8% to 1.6% KOH solutions. Group II included three japonica and Tongil-type glutinous rice varieties, which revealed medium alkali digestion value(ADV) at 1.4% KOH solution and intermediate change in ADV from 0.8% to 1.6% KOH solutions. Most of Tongil-type and early-maturity japonica rice, which exhibited medium-high ADV at 1.4% of KOH concentration and large ADV difference between low and high alkali solutions, were contained in Group III. Group N included most of medium or medium-late-maturity japonica, which showed high ADV at 1.4% KOH and medium or intermediate-high ADV change between low and high alkali solutions. The 1st principal component indicated the average index of ADV through 0.8-1.6% KOH solutions and the 2nd principal component pointed out the factor related with ADV difference between low and high alkali solutions or regression coefficients of ADV change along with the KOH concentrations.

• Journal of the Korean Society of Clothing and Textiles
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• v.10 no.2
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• pp.1-9
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• 1986

To study the effects of surface structure of fiber on the decrement of fatty soil removal at high temperature, the following variables were selected: controled and alkali-treated P.E.T.(polyester) fabrics and chopped fibers as substrates to estimate the detergencies, different aging methods of soiled substrates, and different washing temperatures and surfactant solutions. Radiotagged tripalmitin was used as soil and the detergency was estimated by means of liquid scintillation counting method. The results were as following: The surface of the fiber became rough with many grooves and the hydrophilicity of the fiber was increased and the structure of the fabric became loose by alkali treatment. While the detergency of alkali-treated P.E.T. fabric was better than that of controled P. E. T. fabric, there was no significant differences between the detergencies of controled and alkali-treated chopped fibers. These results indicate that the increment of detergency of alkali-treated P.E.T. fabric is mainly resulted from the changes of fabric structure and the improved hydrophilicity of fiber by alkai treatment. The detergency of tripalmitin was increased with elevating temp. below the m.p. of tripalmitin, was decreased around the m.p., and again was increased above the m.p ..It is considered that the decrement of detergency around the m.p. is due to the diffusion of molten tripalmitin into the grooves on fiber surface, the inner part of fiber, and between fibers. When controled and alkali-treated soiled fabrics and soiled chopped fibers were washed in the distilled water and in the Na-DBS solution respectively, below $60^{\circ}C$ detergencies of alkali-treated fabrics and chopped fibers were improved. However above $60^{\circ}C$ this result was reversed. Therefore these results are regarded as the effects of grooves on fiber surface at high temp. and improved hydrophilicity at low temp. by alkali treatment. When controled and alkali-treated soiled fabrics and soiled chopped fibers were hot-aged before washing, the detergencies of both species were decreased generally. Because the soil was diffused into the grooves on fiber surface, the inner part of fiber, and between fibers during hot-aging. The detergencies of hot-aged species were also decreased above certain temp.. These results suggest that the decrement of detergency at high temp. be resulted not only from the diffusion of soil into the grooves on fiber surface, the inner part of fiber, and between fibers, but also from the characteristics of surfactant solutions.

• Korean Chemical Engineering Research
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• v.45 no.6
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• pp.633-637
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• 2007

Electroless plating of Co-alloy thin films as capping layers for Cu interconnection has been investigated using alkali-free precursors such as $(NH_4)_2Co(SO_4)_2{\cdot}6H_2O$, $(NH_4)_2WO_4$, $(NH_4)H_2PO_4$, etc. The characteristics of the Co-alloy thin films were discussed by analyses of the effects of pH, Co-precursor concentration, and deposition temperature on the thickness and surface morphology of the films. The thickness of the Co-alloy thin films increased with increasing pH, Co-precursor concentration, and deposition temperature, similarly to the results of electroless plating of Co-alloy thin films using alkali-containing chemicals. The SEM images of the surface of the Co-alloy thin films showed that the proper ranges of pH and deposition temperature were 8.5~9.5 and $75{\sim}85^{\circ}C$, respectively. This work found a feasibility that Co-alloy thin films as capping layers for Cu interconnection could be electroless plated using alkali-free chemicals.

• Journal of Korea Foresty Energy
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• v.20 no.1
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• pp.62-72
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• 2001

To elucidate the behaviors of alkali swelllng of woods. the dimensional change in cross section of cell elements of four major Korean woods during alkali swelling were examined by an optical microscory, an imaging analysis method and an X-ray diffrartion During alkali swelling, tracheid diameter of Larix kaempferi wood showed greater swelling property than that of Pinus koraiensis wood, and the cell wall swelled highly over 10% sodium hydroxide solution treatment. The radial diameter of vessel elements in earlywood shrunk, but it swelled slightly in tangential direction. When treated with 5% NaOH, the wall thickness of wood fiber increased about three times over the original one. The thickness of cell wall in all elements and the diameter of wood fiber and tracheid showed almost isotropic shrinkage. The diameter of cell elements during the mercerization process decreased, but cell wall thickness Increased. Crystal transformation of cellulose in wood was not occurred by alkali treatments. but relative crystallinity and crystallite width of the woods increased slightly. Consequently, it was demonstrated that the swelling properties of woods were dependant on wood species, cell elements and alkali concentration.

• Korean Journal of Food Science and Technology
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• v.39 no.2
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• pp.169-174
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• 2007

In this study, we examined the characteristics of alkali gelatinization of corn starch. Here, the degree of corn starch gelatinization increased exponentially with the NaOH concentration of the starch slurry. The alkali gelatinization initiation point (AGIP) was obtained from the intersection point of gelatinization slope line, which resulted from the regression of the logarithmic degree of gelatinization, and was markedly changed. The effects of temperature and corn starch concentration on alkali gelatinization were studied with a 10%(w/w) corn starch suspension. We found that this corn starch suspension gelatinized in 24.1 meq/g starch of NaOH at $40^{\circ}C$, and in 9.8 meq NaOH/g starch at $60^{\circ}C$. Moreover, a 40%(w/w) corn starch suspension gelatinized with 9.5 meq NaOH/g starch, even at $40^{\circ}C$. These results indicate that the amount of alkali added for the gelatinization of corn starch has an inverse relationship with the temperature and concentration of corn starch.

• Resources Recycling
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• v.19 no.4
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• pp.13-18
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• 2010

Effort of reducing wastes and their recycling is increasing in worldwide. Especially, extreme care for alkali recycling is required because of its environmental pollution and its corrosive characteristics. In order to manage alkali wastes effectively, it is necessary to make quality standards for recycling products from the alkali wastes because there are no quality specifications yet. In this study, we selected several recycling candidates from the alkali wastes based on the analysis of the most recent data of the various industrial sites. As a result, the recycling candidates from the alkali wastes are sodium hydroxide, aluminum sulfate, poly aluminum chloride. It is believed that the proper management system for waste products is required in governmental point of view and it propagates positively for resolving various environmental issues.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.1-14
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• 1996

The mixed alkali silicate glasses doped 0.1 mol% $Fe_2O_3$ are fabricated for studying the effect of transition metal oxides, which is related to the $Li^-$ ion movement in Magic-Angle-Spinning NMR. We have investigated the spin-lattice relaxation times in the room temperature and measured the $^7Li$ MAS-NMR spectrum with temperature. When the $Fe_2O_3$ oxides are added in alkali silicate glasses, the width of spectrum is changed a little but the line shape is hardly varied. For this reason, we can think that the mixed alkali effects are shown sufficiently in the spin-spin relaxation processes. However, it is not mixed alkali effects in this case. The activation energy of $Li^-$ ions are diminished in mixed alkali glasses. From the analysis of $Li^-$ diffusion environment, spin-lattice relaxation time and the nuclear magnetization, it is confirmed that the alkali mixed effects are not shown in $^7Li$ spin-lattice relaxation processes.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.810-819
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• 2007

Investigation of alkali activation of fly ash and blast furnace slag was carried out using waterglass and sodium hydroxide. XRD, FTIR, $^{29}Si$ and $^{27}Al$ NMR, TGA and SEM were used to observed the reaction products and microstructure of the fly ash/slag cement (FSC) pastes. The reaction products were amorphous or low-ordered calcium silicate hydrate and aluminosilicate gel produced from alkali activation of blast furnace slag and fly ash, respectively. On the basis of this investigation, waterglass solution with a modulus(Ms) of 1.0 and 1.2 is recommended for alkali activation of fly ash and blast furnace slag. Morphology of FSC pastes alkali-activated with Ms of 1.0 and 1.2 shows a more solid and continuous matrix due to restructuring of gel-like reaction products from alkali-activated fly ash and blast furnace slag together with another hydrolysis product(i.e., silica gel) from water glass.