• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.708-710
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• 2001

In this paper, back commutation phenomena for iron chute chamber in AC low testing. For this experimental we used high speed camera and carried out with same prospective currents up to 10kA RMS. Hybrid arc quenching chambers which are composed with iron plate and insulating materials tested for reducing back commutation phenomena in interrupting process. It is shows that hybrid chambers which are various narrow slot path width reduces back commutation. As a result, a new type arc quenching chamber is to force the arc rapidly into a narrow insulating slot with iron plate. By this means the arc is lengthened and squeezed between insulating walls. Using this model, the behavior of the arc squeezed in the hybrid chamber and characteristics of arc voltage are also investigated.

• Journal of Welding and Joining
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• v.19 no.5
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• pp.481-485
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• 2001

Laser cladding processing allows rapid transfer of heat to the material being processed with minimum conduction into base metal. The effect of $CO_2$ laser cladding with high viscosity mixed powders was investigated. High viscosity mixed powder consists of bronze powder and flux that is used at a high temperature condition. The mixed powder has a high viscosity that it can be easily pasted over a curved or slope substrate. The device for mixed powder was designed and manufactured. It consists of the high viscosity mixed powder feeding system, the preheating system and the shielding gas system which prevents the clad layer from being oxidized. The results of experiment indicated that the feed rate of high viscosity mixed powder was important for later cladding with mixed powder feeding. The high viscosity mixed powder and substrate must be preheated to prevent porosity from breaking at the clad layer. The experimental result shows that the high viscosity mixed can be applied for laser cladding process.

• Journal of the Korean Wood Science and Technology
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• v.20 no.1
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• pp.23-27
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• 1992

81.9% of the cellulose delignified by acetosolv process was hydrolyzed in HCl-$AlCl_3$ hydrolysis system when $AlCl_3$ was used as catalyst in breaking down of glycosidic bond of cellulose. It was well compared that the HCl hydrolysis system without $AlCl_3$ as catalyst showed only 60~61% of the hydrolyzed yield. Also monosaccharide yield including glucose clearly increased when $AlCl_3$ was use. When concentration of HCl and $AlCl_3$ was increased, the hydrolyzed monosaccharide was increased within certain range. The monosaccharid yield out of the hydrolyzed reached 55.4% at optimum conditions which were identified as 20% of Hel solution, 0.03 Mol of $AlCl_3$, $120^{\circ}C$ of reaction temperature and 7 hours of reaction time employed in this study.

• Bulletin of the Korean Chemical Society
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• v.35 no.6
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• pp.1754-1758
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• 2014

The nucleophilic substitution reactions of bis(Y-aryl) chlorothiophosphates (1) with X-pyridines are investigated kinetically in acetonitrile at $35.0^{\circ}C$. The free energy relationships with both X and Y are biphasic concave upwards with a break point at X = 3-Ph and Y = H, respectively. The sign of cross-interaction constants (CICs; ${\rho}_{XY}$) is positive with all X and Y. Proposed mechanism is a stepwise process with a rate-limiting leaving group departure from the intermediate with all X and Y. The kinetic results of 1 are compared with those of Y-aryl phenyl chlorothiophosphates (2). In the case of Y = electron-withdrawing groups, the cross-interaction between Y and Y, due to additional substituent Y, is significant enough to change the sign of ${\rho}_{XY}$ from negative with 2 to positive with 1, indicative of the change of mechanism from a rate-limiting bond formation to bond breaking.

• Journal of the Korean Home Economics Association
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• v.8 no.1
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• pp.87-92
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• 1970

Recently it has become a common belief that ascorbic acid comes to break up in the process of making its color after peeling it. In this study the writer has attempted to observe whethier ascorbc acid really breaks up or not, what percentage of salt is needed in water to keep ascorbic acid in the best condition. Ascorbic acid was quantified by the spectrophotometric method. The results were obtained as follows; It seems that ascorbic acid does not break up considerably in mixing by the imxer for two minutes and if the mixing lasts longer ascorbic acid breaks up by heat and presumably by enzyme and oxidation. Generally at our home the breaking of ascorbic acid usually does not appear so much as only two minutes, mixing gives us the desirable result.

• Journal of Information Technology Applications and Management
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• v.11 no.1
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• pp.175-187
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• 2004

Many companies have integrated their internal processes with the aid of information technology. Now the focus is on interconnecting trading partners. Collaborative commerce (also known as c-Commerce) has a key role. It is not just about making it easier for business to communicate. It is about by breaking down barriers along the entire length of the supply chain. Some c-Commerce links are permanent, others get established when and where they are needed. c-Commerce is helping business in electronic supply chains to improve product delivery while cutting costs, to strengthen relationships and to reduce lead time. In this paper, we propose the concept of collaborative commerce, and design and implement Collaborative Commerce Portal (CCP) system of small and medium enterprise for marketing support. The technical definition of CCP is set of all technical elements can do collaborative commerce between small and medium enterprises with Internet or Internet. The target information of CCP includes usual and unusual information and all other information of companies used as process events. Through this, it enhances efficiency of business processes, core information sharing and marketing activation.

• Journal of the Korean Ceramic Society
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• v.33 no.6
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• pp.631-636
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• 1996

The powder characteristics of UO2 via AUC prepared by precipitation from a UN with AC soiution produced from nuclear fuel powder conversion plant and that of the existing facility were compared. Mean particle size of AUC powder was decreased and agglomerates were much occured in case of using the AC solution that that of the gases but other properties such as particle size distribution and shape of particle are thought to be similarly. In compaction of UO2 powder the breaking pressur of agglomerated UO2 powder and the sintered density of final UO2 pellet from AC solution were measured 1.45$\times$108 N/m2 and 10.52 g/cc, These values could be used in nuclear fuel powder fabrication process.

• Transactions of The Korea Fluid Power Systems Society
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• v.4 no.4
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• pp.21-27
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• 2007

A hydraulic breaker for construction machinery generally used for the destroying and disassembling of buildings, crashing road pavement, breaking rocks at quarry and so on. So the measurement of the impact energy of a hydraulic breaker is very important thing to prove its capability to manufacturers and customers. Therefore the prediction of impact energy in design process is very helpful to the most of breaker manufacturers. In this study, we carried on modeling and simulation of a hydraulic breaker to predict impact energy via commercial CAE software. The modeling and simulation of a hydraulic breaker was achieved with two parts. One is a hydraulic circuit analysis part via AMESim and the other is impact strain analysis part via ANSYS.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.2 s.233
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• pp.205-213
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• 2005

The drop ejection process from a micro nozzle is investigated by numerically solving the conservation equations for mass and momentum. The liquid-gas interface is tracked by a level set method which is extended for two-fluid flows with irregular solid boundaries. Based on the numerical results, the liquid jet breaking and droplet formation behavior is found to depend strongly on the pulse type of forcing pressure and the contact angle at the gas-liquid-solid interline. The negative pressure forcing can be used to control the formation of satellite droplets. Also, various nozzle shapes are tested to investigate their effect on droplet formation.

• Journal of Agricultural Extension & Community Development
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• v.4 no.1
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• pp.15-27
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• 1997

This paper reviews the concept and limits of rural community development, examines the relation between consciousness education and movement, and suggests the model of social consciousness education to rural community movement. Since consciousness education is closely related to social movement methodologically, organizational and systematic community development movements for re-structuring the urban-oreiented policies and education which back up them be followed as natural consequence. Based upon the results of this study, the new paradigm is suggested. As shown in the model, new understanding of urban-rural continuum theory, new roles and concept of social consciousness education should be emphasized to solve the contemporary rural community problems. The organizational community development movement for the rural-oriented policy should be an essential process, and peoples' re-orientation, such as 'breaking stereotype', 'assumming a critical thinking toward social reality' etc., is the indispensible background of successful movement.