• Archives of Pharmacal Research
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• 제20권2호
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• pp.184-190
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• 1997

A new method based on the chemical reaction has been devised for the sequential analysis of reducing oligosaccharides using 8-amino-2-naphthalenesulfonic acid (ANS), a fluorescent precolumn derivatization reagent for reducing saccharides. The procedure established includes 1) the derivatization of a reducing oligosaccharide to produce a Schiff base, 2) the reduction of the base with sodium cyanoborohydride $(NaBH_3/CN), 3)$ the methoxycarbonylation of the resultant secondary amino group, 4) the cleavage of the glycoside bond next to the reducing end, based on the intramolecular acid hydrolysis by the action of a sulfonic acid group of the ANS derivative, 5) the identification of the liberated reducing end by high-performance liquid chromatography (HPLC), and finally 6) the recovery of the resultant oligosaccharide fragment from the cleavage reaction mixture. The extensive examination of the conditions for the sequential analysis of reducing oligosaccharides resulted in the procedure of simplicity , high selectivity and high recovery. This procedure was found to be useful for the sequential analysis of di-, tri- and tetrasaccharides.

• 산업경영시스템학회지
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• 제43권3호
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• pp.41-52
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• 2020

This paper investigates the stress-reducing preventive maintenance model through numerical experiments. The preventive maintenance model is used to analyze the relationship between related conditions and variables to gain insight into the efficient operation of the system when performing preventive maintenance in real-world situations. Various preventive maintenance models have been developed over the past decades and their complexity has increased in recent years. Increasing complexity is essential to reflect reality, but recent models can only be interpreted through numerical experiments. The stress-reducing preventive maintenance is a newly introduced preventive maintenance concept and can only be interpreted numerically due to its complexity, and has received little attention because the concept is unfamiliar. Therefore, for information purposes, this paper investigates the characteristics of the stress-reducing preventive maintenance and the relationship between parameters and variables through numerical experiments. In particular, this paper is focusing on the economic feasibility of stress-reducing preventive maintenance by observing changes in the optimal preventive maintenance period in response to changes in environmental stress and the improvement factor. As a result, when either the environmental stress or the improve effect of stress-reducing preventive maintenance is low, it is not necessary to carry out the stress-reducing preventive maintenance at excessive cost. In addition, it was found that the age reduction model is more economical than the failure rate reduction model.

• Environmental Engineering Research
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• 제19권1호
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• pp.41-45
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• 2014

The peels of Carya cathayensis Sarg. (PCCS) were treated under subcritical water conditions ($130^{\circ}C$ to $280^{\circ}C$ for 0 to 120 min). The extract from PCCS included reducing sugar, proteins, and compounds with radical scavenging activity. Addressing the reducing sugar that is a resource of bioethanol, we could maximize the reducing sugar under the subcritical water ($190^{\circ}C$ for 60 min) and obtain 0.24 g/g-sample together with 9.7 units/mg-sample of radical scavenging activity. The obtained extract was estimated to correspond to 1 L of bioethanol/100 g-sample. It was therefore considered that the treatment by subcritical water could yield reducing sugar and natural compounds with radical scavenging activity.

• 한국생산제조학회지
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• 제8권1호
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• pp.112-118
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• 1999

Aluminum alloy, which is advantageous to machining and injection, makes a great contribution to shortening in delivery time, infection cycle time and reducing expense. This study presents machining conditions for mild materials and describes the difference between theoretical and practical machined surface roughnesses affected by various machining conditions. Machining results have been evaluated and analyzed under varying machining conditions. Special properties of the mild materials have been presented by the quantitative analysis and the optimal machining condition has been proposed for the mild materials.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 INTERNATIONAL SYMPOSIUM ON SOIL & GROUNDWATER ENVIRONMENT
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• pp.182-182
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• 2005

• 패션비즈니스
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• 제15권4호
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• pp.144-154
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• 2011

Polygoum tinctoria dye is the one using the method of reducing dyeing, and so is made by the mechanism different from natural dye in general, and the reproductive dye is more difficult because it varies in accordance with manufacturing method and days being manufactured in case of natural indigo dye that has been used traditionally. In addition, overall analysis is short of color changes in accordance with natural dyeing condition and barely none of the research for cellulose system such as cotton in particular. Accordingly, this study tries to research on the natural dyeing method optimal for color development that is desirable in designing and development of natural dyeing as comparing and contemplating the change of dyeing quality and color in accordance with reduction temperature and time, reductant quantity, dyeing temperature and time, NaOH quantity, and dyeing repetition times in order to expand dyeing methods and use variously polygoum tinctoria by improving traditional dyeing methods as well as to establish exact dyeing method of cotton which is a fabric of cellulose system in order to make such polygoum tinctoria quantificated and reproductive. The optimum conditions in the dyeing procedure are as follows: Reducing temperature is $50^{\circ}C$. Added concentration of the reducing agent is $3g/{\ell}$. Reducing time is 30minutes. Dyeing temperature is $30^{\circ}C$. Added concentration of NaOH is $1g/{\ell}$. Dyeing time is 30minutes.

• Bulletin of the Korean Chemical Society
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• 제15권10호
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• pp.873-881
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• 1994

The approximate rate and stoichiometry of the reaction of excess diisobutylaluminum hydride-dimethyl sulfide complex($DIBAH-SMe_2$) with organic compounds containing representative functional group under standardized conditions (toluene, $0{\circ}C$) were examined in order to define the reducing characterstics of the reagent and to compare the reducing power with DIBAH itself. In general, the reducing action of the complex is similar to that of DIBAH. However, the reducing power of the complex is weaker than that of DIBAH. All of the active hydrogen compounds including alcohols, amines, and thiols evolve hydrogen slowly. Aldehydes and ketones are reduced readily and quantitatively to give the corresponding alcohols. However, $DIBAH-SMe_2$ reduces carboxylic acids at a faster rate than DIBAH alone to the corresponding alcohols with a partial evolution of hydrogen. Similarly, acid chlorides, esters, and epoxides are readily reduced to the corresponding alcohols, but the reduction rate is much slower than that of DIBAH alone. Both primary aliphatic and aromatic amides examined evolve 1 equiv of hydrogen rapidly and are reduced slowly to the amines. Tertiary amides readily utilize 2 equiv of hydride for reduction. Nitriles consume 1 equiv of hydride rapidly but further hydride uptake is quite slow. Nitro compounds, azobenzene, and azoxybenzene are reduced moderately. Cyclohexanone oxime liberates ca. 0.8 equiv of hydrogen rapidly and is reduced to the N-hydroxylamine stage. Phenyl isocyanate is rapidly reduced to the imine stage, but further hydride uptake is quite sluggish. Pyridine reacts at a moderate rate with an uptake of one hydride in 48 h, while pyridine N-oxide reacts rapidly with consumption of 2 equiv of hydride for reduction in 6h. Similarly, disulfides and sulfoxide are readily reduced, whereas sulfide, sulfone, and sulfonic acid are inert to this reagent under these reaction conditions.

• Bulletin of the Korean Chemical Society
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• 제12권6호
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• pp.644-649
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• 1991

The approximate rates and stoichiometry of the reaction of excess lithium tris(dibutylamino)aluminum hydride (LT-DBA) with selected organic compounds containing representative functional groups under standardized conditions (tetrahydrofuran, $0^{\circ}C$) were studied in order to characterize the reducing characteristics of the reagent for selective reductions. The reducing ability of LTDBA was also compared with those of the parent lithium aluminum hydride and the alkoxy derivatives. The reagent appears to be much milder than the parent reagent, but stronger than lithium tri-t-butoxyaluminohydride in reducing strength. LTDBA shows a unique reducing characteristics. Thus, the reagent reduces aldehydes, ketones, esters, acid chlorides, epoxides, and amides readily. In addition to that, ${\alpha},{\beta}$-unsaturated aldehyde is reduced to ${\alpha},{\beta}$-unsaturated alcohol. Quinones are reduced to the corresponding diols without evolution of hydrogen. Tertiary amides and aromatic nitriles are converted to aldehydes with a limiting amount of LTDBA. Finally, disulfides and sulfoxides are readily reduced to thiols and sulfides, respectively, without hydrogen evolution.

• 한국염색가공학회지
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• 제26권3호
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• pp.237-241
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• 2014

The aim of this study is to develop an eco-friendly reduction process of indigo as an alternative choice. Hansenula misumaiensis was used and their reducing activity toward synthetic indigo as well as natural indigo was estimated by dyeing test in terms of indigo dye uptake. The changes in K/S value and pH were monitored on the time-based measurements. Also, reduction duration was evaluated. On the basis of the results described in this study, it was confirmed that Hansenula misumaiensis reduced indigo. Reducing power of Hansenula misumaiensis reached to maximum in two days. It can be possible to develop eco-friendly process of indigo reduction using Hansenula misumaiensis by the optimization of strain culture conditions and the optimization of reduction conditions.

• 한국전기전자재료학회논문지
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• 제36권4호
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• pp.418-421
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• 2023

Multilayer Ceramic Capacitors (MLCCs) are essential passive components in the electronics industry, known for their high capacitance due to the multilayer structure comprising inner electrodes and dielectric layers. Nickel electrodes are commonly used in MLCCs as the inner electrodes, and to prevent oxidation during the co-firing of the dielectric layers with nickel electrodes, reducing atmosphere is required. However, reducing atmosphere sintering can also induce a reduction of the dielectric, necessitating precise control of oxygen partial pressure. To explore the possibility of using oxide electrodes that do not require reducing atmosphere sintering, we analyze the electrical properties of nickel oxide (NiO) as a potential candidate. As a preliminary study on its use as an alternative inner electrode, the correlation between microstructure and electrical properties of bulk NiO under different sintering conditions was investigated to gain insights into the conduction mechanisms of the material.