• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.55-65
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• 1998

The oxidation behavior of Ag-36.8a%Cu-7.4at%Ti alloy brazed on Si3N4 substrate was investigated at 400, 500 and 600$^{\circ}C$ in air. Under this experimental condition Si3N4 and Ag were not oxidized whereas Cu and Ti among the brazing alloy components were oxidizied obeying the parabolic oxidation rate law. The activation energy of oxidation was found to be 80kj/ mol which was smaller than that of pure Cu owing to the presence of oxygen active element of Ti. The outer oxide scale formed from the initial oxidation state was always composed of Cu oxides which were known to be growing by the outward diffusion of Cu ions. As the oxidation progressed the concentration gradient occurred due to the continuous consumption of Cu as Cu oxides and consequently build-up of an Ag-enriched layer below the Cu oxides resulted in the formation of multiple oxide scales composed of Cu oxide (CuO) /Ag-enriched layer/Cu oxide (Cu2O) /Ag-enriched layer. Also the inward diffusing of oxygen through Cu oxide and Ag-enriched layers led to the formation of internal oxides of TiO2.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.23-29
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• 2019

This study applies to the surface modification technique by coating the surface of aggregates using the modified paste such as cementitious materials in order to develop completely recycling technology of coarse aggregate. In this case, coating thickness of modified aggregate can be considered that the decision is dependent on the viscosity and tenacity of modified paste. In this study identify the flow properties of the fresh modified paste, and examined for the coating thickness of modified aggregate. As a result, it was possible to design a quantitative coating thickness of modified paste assuming that a modified paste to a Bingham Fluid and consider by excess paste theory and rheology constant (yield value). Accordingly, it is considered that the quantitative mix design of concrete using by surface modified aggregates will be possible.

• Composites Research
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• v.34 no.3
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• pp.148-154
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• 2021

Carbon/epoxy composite bipolar plate (BP) is a BP that is likely to replace existing graphite bipolar plate of vanadium redox flow cell (VRFB) due to its high mechanical properties and productivity. Multi-functional carbon/epoxy composite BP requires graphite coating or additional surface treatment to reduce interfacial contact resistance (ICR). However, the expanded graphite coating has the disadvantage of having low durability under VRFB operating conditions, and the surface treatments incur additional costs. In this work, an excessive resin absorption method is developed, which uniformly removes the resin rich area on the surface of the BP to expose carbon fibers by applying polyester fabric. This method not only reduces ICR by exposing carbon fibers to BP surfaces, but also forms a unique ditch pattern that can effectively hold carbon felt electrodes in place. The acidic environmental durability, mechanical properties, and gas permeability of the developed carbon/epoxy composite BP are experimentally verified.

• Journal of Advanced Navigation Technology
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• v.25 no.6
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• pp.517-522
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• 2021

Optical dispersion-managed link combined with optical phase conjugation for compensating of the distorted optical signals due to chromatic dispersion and nonlinear effects, which is required to implement long-haul wavelength division multiplexed system, is proposed and assessed in viewpoint of network topology flexibility. Optical phase conjugator capable to compensate for the distorted optical signal due to nonlinear effects is placed non-midway of total transmission distance. And, in dispersion-managed link, residual dispersion per span (RDPS) of each fiber spans in former half section and latter half section with respect to optical phase conjugator are different to each other. Simulation results show when the RDPS of each fiber sections in one half section makes it's own net residual dispersion slight different from another half section's net residual dispersion, the compensation effect in the proposed link configuration is more increased.

• Journal of the Economic Geographical Society of Korea
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• v.19 no.3
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• pp.512-534
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• 2016

This paper is to see what appears to be an economic crisis as urban crisis, to explore its emerging process and its major distinctive figures in the context of S. Korea, and to consider alternatives to overcome such an urban crisis. For this purpose, it first tries to show that the capitalist economic development (i.e. capital accumulation) has been stimulated and driven largely by extending investments into built environments. Then it analyzes how crises of overaccumulation, coupled with other crises such as the IMF crisis in 1997 and the financial crisis in 2008 which have been brought about by serious impacts of foreign financial capitals working on the global level, have led to accumulating of huge surplus reserves within both big companies and the central government on the one hand, increasing tremendously debts of households as well as government and private companies on the other. In particular, the debt crisis seems to be accelerated by fictitious capital generated through government's financial strategies to promote both supplies and demands in housing and property markets. There seem several ways of overcoming the urban crisis spiraled around accumulating surplus capital and increasing financial debt; raising real income, moderating investments into built environment, and increasing inputs into the fields of technology and well-being. In order to open up these ways, it is concluded, recent urban movements in terms of the right to the city are required not only to make the government and capital to do so, but also to realize interest of urban people who have produced such surplus but who are suffering from the debt crisis.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1181-1190
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• 2014

In this study, the erosional parameters for deposit beds were quantitatively estimated domestically for the first time through the erosion tests using an annular flume. Four erosion tests were carried out for the deposit beds with different consolidation structures, which were obtained by consolidating the kaolinite slurries for a given time durations. Results of erosion tests showed that the bed shear strength ${\tau}_s$ increased with the consolidation time and bed depth. The erosion rate ${\epsilon}$ was also shown to be related well with the excess shear stress ${\tau}_b-{\tau}_s$ which was given by the difference between flow shear stress ${\tau}_b$ and bed shear strength ${\tau}_s$. While the logarithm of the erosion rate was linearly related with the excess shear stress as ${\tau}_b-{\tau}_s{\geq}0.1N/m^2$, however, the erosion rate decreased rapidly with it when ${\tau}_b-{\tau}_s{\leq}0.1N/m^2$. These erosion test results were also shown to be good enough to verify by comparing with the test results from previous studies and a new equation was suggested to describe the erosion rate more well in the region of ${\tau}_b-{\tau}_s{\leq}0.1N/m^2$.

• Journal of Energy Engineering
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• v.24 no.2
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• pp.9-16
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• 2015

As electricity is an indispensable input to human's existence and industrial production, economic benefits arise from consumption. The economic benefits of the electricity consumption are useful information in various fields of electricity-related policy. Therefore, this study attempts to value the economic benefits from electricity use. The economic benefit of electricity consumed is the area under the demand curve which made of the sum of the actual consumer expenditure and the consumer surplus. Consumer expenditure can be easily observed but the information on price elasticity of demand is necessarily required to compute consumer surplus. This study derives the estimates for price elasticities through literature review. The price elasticities of the electricity demand for residence, industry, and commercial are estimated to be -0.332, -0.351, and -0.263, respectively. Because the consumer surplus of the electricity consumption for residence, industry, and commercial are computed to be 191.54, 143.44, and 231.91 won per kWh, respectively. Given that average prices of electricity use were 127.02, 100.70, and 121.98 won per kWh for the year 2013, the economic benefit are calculated to be 318.56, 244.14, and 353.89 won per kWh, respectively. We can convert the values to 321.96, 246.75, and 357.67 won per kWh in 2014 constant price, respectively, using consumer price index. They can be used in the economic feasibility analysis of a new electricity supply project.

• Journal of Technology Innovation
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• v.20 no.1
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• pp.45-73
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• 2012

In this paper, we analyse empirically the effects of financial characteristics on the relationship between R&D investment and market value of firms listed on Korea Exchange. The main results of this study can be summarized as follows. Firm size increase the market valuation of R&D investment because it provides economies of scale, easier access to capital market, and R&D cost spreading. Market share also positively effects the relationship between R&D investment and firm value. Alternatively, free cash flow has a negative effect on the relationship between R&D investment and firm value because firms with high free cash flow could be tempted to use the free cash flow to undertake negative NPV projects. The dependence on external finance is a handicap negatively assessed by the market when firms undertake R&D projects due to the higher information asymmetry associated with this kind of project. Labor intensity has a negative effect on the relationship between R&D investment and firm value because the abnormal profits arising from R&D investment are diluted among employees. Capital intensity also has a negative effect on the relationship between R&D investment and firm value due to the greater financial constraints faced by capital intensive firms. In conclusion, several financial characteristics(firm size and market share) positively effect the relationship between R&D investment and firm value, while others(free cash flow, dependence on external finance, labor intensity, and capital intensity) exert a negative effect. Therefore, we conclude that the effectiveness of R&D investment depends on these financial characteristics.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.273-282
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• 2017

The purpose of this study is to investigate the changes in the recovery of equipment using full containers loaded with freight instead of direct container transportation according to the sales policy considering the cost of transporting the containers. The EMU operation case was analyzed. The policies implemented by Company A to provide EMU credits depended only on the relative accountability contribution margin per box (RA CMPB) for the profitability of backhaul full freight. Therefore, these policies resulted in limitations in sales based on profitable accountability (PA) CMPB, which is more profitable. Moreover, while some Asian regions have surplus equipment, many Asian destinations to which their freight is exported have equipment shortages. Thus, in some cases, service sales to the regions with surplus equipment generated greater company-wide profits when compared with the return of empty containers or sales to the regions with insufficient equipment. In other words, the conditions for providing EMU credits should be changed, and even the full freight between regions with surplus equipment should be provided with credit amounts in which potential factory and transport costs in a destination are pre-reflected.

• Journal of Korean Philosophical Society
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• v.126
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• pp.191-212
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• 2013

Cet article consiste ${\grave{a}}$ critiquer $l'{\acute{e}}conomie$ libidinale, $subordonn{\acute{e}}e$ ${\grave{a}}$ l'ordre phallique qui coupe les flux libidinaux. La notion lacanienne du $d{\acute{e}}sir$ qui est $focalis{\acute{e}}e$ sur le manque, ne pourrait prendre en compte la dimension $cr{\acute{e}}ative$ et productive du $d{\acute{e}}sir$ qui est $li{\acute{e}}e$ ${\grave{a}}$ la perspective deleuzienne et guattarienne du $d{\acute{e}}sir$. La $possibilit{\acute{e}}$ de la $d{\acute{e}}rive$ et de la $d{\acute{e}}stratification$ des flux libidinaux pourrait se mener vers la notion du "homo surplus", laquelle est la notion $in{\acute{e}}dite$ que j'ai $cr{\acute{e}}e$. Le surplus est ce qui $d{\acute{e}}passe$ la logique phallogocentrique par son $immensurabilit{\acute{e}}$ et sa surabondance. Dans cette perspective, la critique virulente de la notion du plaisir $cantonn{\acute{e}}$ dans la partie $g{\acute{e}}nitale$, $s^{\prime}op{\grave{e}}re$ avec l'analyse de la jouissance qui est non phallique; Cette jouissance non phallique est $li{\acute{e}}e$ ${\grave{a}}$ l'agencement non $lin{\acute{e}}aire$ et multiple des pratiques sexuelles $in{\acute{e}}dites$ et radicales.