• Journal of the Korean Wood Science and Technology
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• v.45 no.2
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• pp.182-194
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• 2017

The optimum alkali pretreatment parameters (reaction time, reaction temperature and potassium hydroxide concentration) for facilitate the conversion into fermentable sugar (glucose) from steam exploded (severity log Ro 2.45) barley husk were determined using Response Surface Methodology (RSM) based on a factorial Central Composite Design (CCD). The prediction of the response was carried out by a second-order polynomial model and regression analysis revealed that more than 88% of the variation can be explained by the models. The optimum conditions for maximum cellulose content were determined to be 201 min reaction time, $124^{\circ}C$ reaction temperature and 0.9% potassium hydroxide concentration. This data shows that the actual value obtained was similar to the predicted value calculated from the model. The pretreated barley husk using acid hydrolysis resulted in a glucose conversion of 94.6%. This research of steam explosion and alkali pretreatment was a promising method to improve cellulose-rich residue for lignocellulosic biomass.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.411-417
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• 1994

For the analysis of fine ceramics, which is one of the new materials difficult to be dissolved, the methods of sample pretreatments such as alkali fusion and high pressure acid digestion were studied using inductively coupled plasma-atomic emission spectrometer(ICP-AES). For the Al2O3 powder sample, the results from high pressure acid digestion method showed better reproducibility than those obtained by alkali fusion technique. In the case of the analysis of SiC powder using the former method, impurities of the powder in the range of ppm were determined without matrix interference by removing Si as Si-F volatilization. Japan Certified Reference Materials (JCRM022 and JCRM023) were analyzed by this method for ultra fine powder and the results showed high accuracy and good reproducibility.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.284-289
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• 1993

The effect of oil refining processes-degumming, alkali-refining, bleaching and deodorizing-on oil characteristics and oxidation stability of sesame oil were investigated. The colors(L, a, b) of samples were markedly changed and their peroxide and acid values were decreased, while the other characteristics of samples were not changed during refining stages. The L values of alkali-refined, bleached and deodorized sesame oils were largely decreased and their a values were increased due to browning reaction during the storage at $70^{\circ}C$. The colors of crude and degmmed sesame oils were very stable and their peroxide, free fatty acid and conjugated dienoic acid values were slowly increased. Volatile carbonyl compounds formed by oxidation were increased during the storage at $70^{\circ}C$. The results indicated that refining processes did not affect the sesame oil characteristics but decreased the oxidation stability of sesame oil.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.251.2-251.2
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• 2010

Plant biomass has been proposed to be an alternative source for petroleum-based chemical compounds. Especially, phenolic chemical compounds can be obtained from lignin by chemical depolymerization processes because lignin consists of complex aromatic polymer such as trans-p-coumaryl, coniferyl and sinapyl alcohols, etc. Phenolic chemical compounds from lignin were usually produced in super critical water. However, we applied Near-critical water (NCW) system because NCW is known as a good solvent for lignin depolymerization. Organic matter like lignin can be solved in NCW system and the system has a unique acid-base property without conventional non-eco-friendly chemicals such as sulfuric acid and sodium hydroxide. In this work, we tried to optimize the NCW depolymerization system by adjusting the processing variables such as reaction time, temperature and pressure. Moreover, the amount of additional phenol was optimized by changing the molar ratio between water and phenol. Phenol was used as capping agent to prevent re-polymerization of active fragment such as formaldehyde. Alkali-lignin was used as a starting material and characterized by a Solid State 13C-NMR, FT-IR and EA (Elemental Analysis). GC-MS analysis confirmed that o-cresol, p-cresol, anisole and 4-hydroxyphathalic acid were the main product and they were quantitatively analyzed by HPLC.

• Macromolecular Research
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• v.14 no.5
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• pp.545-551
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• 2006

Aqueous dispersions of pristine and functionalized (COOH- and $NH_2$-) multi-walled, carbon nanotubes (MWNTs) were prepared by using three types of surf act ants: sodium dodecyl sulfate (SDS, anionic), PEO-PPO-PEO (Pluronic P84, non-ionic), and poly(styrene/$\alpha-methyl$ styrene/acrylic acid) random terpolymer, i.e., alkali-soluble resin (ASR). The aggregate size, $\zeta-potential$, and storage stability of the MWNT aqueous dispersions were investigated by using dynamic light scattering and the turbidity method at room temperature. The exfoliation of the MWNT aggregates was determined by a UV-visible spectrophotometer and the morphology of the surfactant-coated MWNTs was observed by transmission electron microscopy (TEM). In all cases, ASR showed better dispersion stability with the smallest aggregate size, compared with the other surfactants, because of its unique molecular structure, i.e., randomly incorporated carboxylic acid groups and planar phenyl groups that can be irreversibly and effectively adsorbed on the MWNT surface. A predominantly-exfoliated morphology of MWNTs was observed in the presence of ASR from the strong intensity of the UV-vis spectrum at 263 nm.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.5-11
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• 1993

First crop of alfalfa (Medicago sativa L.) was harvested, wilted and ensiled with or without NaOH or $NH_3$, and fed to three rumen fistulated goats in a $3{\times}3$ Latin-square design. Each alkali treatment (2.44% of alfalfa dry matter) was made by spraying its solution prior to ensiling. Silage pH, $NH_3-N$ and butyric acid concentration were increased with each alkali addition, and NaOH-treated silage showed the lowest chemical quality. Compared with untreated silage, digestibilities of organic matter, ADF and cellulose were depressed by both alkali treatments, and the reductions in NaOH-treated silage were significant. Crude protein digestibility was also significantly decreased in NaOH-treated silage, but the goats receiving the silage excreted less nitrogen in urine than those on the other two silages. Nitrogen retention of goats was not different among the treatments. Ruminal solubility and potential degradability of dry matter and nitrogen determined with the in situ bag technique were reduced, and rate of degradation of the two components were increased by the NaOH treatment. Addition of $NH_3$ provided ruminal soluble nitrogen to the silage, but the rate of degradation was similar to that of untreated silage. These results suggest that NaOH treatment would denature the protein and reduce the susceptibility to microbial degradation in the rumen, while no positive effect of alkali treatment on fiber digestion and nitrogen utilization was observed in this study.

• Journal of Korea Society of Industrial Information Systems
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• v.9 no.4
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• pp.8-15
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• 2004

Gilding process make thin membrane with other metals to surface of metal and metalloid. It control the hydrogen ion and oxalic acid density with rinsing work since the process used to acid and alkali. Therefore, in this study, several control method applied the gilding process. It desired to the optimal controller and their results can be save on water resource by useful feed of rinsing. And there is quite a possibility of uniform production due to fixed control of acid and alkali. Also it can be contributed the competition power because of lower production unit cost. Especially, this control method to be developed can be applied to any process without mathematical model. And it can be changed their algorithm more easily, if control object is changed.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.200-205
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• 2016

With high specific surface area and pore structural diversity, MOFs show important applications in gas storage, catalysis, sensing, separation, and biomedicine. However, the stability of the structure of MOFs has restricted their application and development. In this study, zirconium metal organic frameworks with 9,10-dicarboxylic acid anthracene as ligand, named UIO-66 ($H_2DCA$), were synthesized and their properties and structures were characterized by XRD, SEM, and $N_2$ adsorption. We focus on the stability of the structure of UIO-66 ($H_2DCA$) under different conditions (acid, alkali, and water). The structural changes or ruins of UIO-66 ($H_2DCA$) were traced by means of XRD, TG, and FT-IR under different conditions. The results show that the UIO-66 ($H_2DCA$) materials are stable at 583 K, and that this structural stability is greatly influenced by different types of acid and alkali compounds. Importantly, we found that the structures maintain their stability in environments of nitric acid, triethylamine, and boiling water.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.145-151
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• 1996

The effectiveness of physiological or chemical acid - alkali solution was investigated as the method to control pH value of nutrient solution in hydroponics dynamically. Lettuces were cultivated using NH$_4$H$_2$PO$_4$ as physiological acid and NaNO$_3$ as physiological alkali or H$_2$SO$_4$ as chemical acid in dynamic control system. The pH of nutrient solution was controlled satisfactorily in the range of pH 5.5-6.5, regardless of treatments. Chemical acid changed pH of solution faster than chemical acid when supplied to the nutrient solution. Any of them did not show any harmful symptom. It is recommended that chemical acid is preferred during the growing stage and physiological acid like as NH$_4$H$_2$PO$_4$ is preferred from several days before harvest stage.

• Journal of the Korean Home Economics Association
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• v.39 no.1
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• pp.91-102
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• 2001

The non-starch polysaccharides in the cell wall of rice, glutinous rice, and black rice, were analyzed. They were fractionated into fractions; water-soluble, hot writer-soluble, ammonium oxalate-soluble, sodium hydroxide-soluble, potassium hydroxide-soluble, and the alkali-insoluble, according to the solvent solubility. The dietary fiber contents were 5.4% in glutinous rice, 4.2% in rice and 7.5% in black rice. The sodium hydroxide soluble fibers were abundant in each kind of rice, especially 4.01% in black rice. The water soluble fibers were 80% of dietary fiber in glutinous rice, 66% in rice, 86% in black rice. It was supposed that the content of the water soluble fibers in rice was increased by pounding. Pectic substances in water soluble fibers, hot water soluble fibers, and ammonium oxalate soluble fibers fraction, were 2.4% in glutinous rice fraction,1.59% in rice, and 1.12% in black rice. Alkali soluble fibers were considered as hemicellulose. Black rice contained 5.80% of hemicellulose, which was more than twice as much as glutinous rice(2.58%) and rice(2.22%). Alkali insoluble fibers were considered as cellulose, which showed no considerable difference. Among samples content of uronic acid in glutinous rice, rice and black rice were 0.9%, 0.66%, 1.8% respectively. Uronic acid of black rice was twice more than other samples tested. The fraction of black rice that uronic acid was extracted at most was the fraction of sodium hydroxide. Mono saccharides of the fraction was the glucose, the arabinose, the xylose.