• Tribology and Lubricants
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• v.17 no.4
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• pp.297-306
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• 2001

Under the condition of variable density and specific heat, maximum pressure, maximum temperature, bearing load, friction and side leakage in high-speed journal bearing operation are examined within some degree of Journal misalignment. The results are compared with the calculation results under the conditions of constant density and specific heat, and variable density and constant specific heat. It is found that the condition of variable density and specific heat play important roles in determining friction and load of Journal bearing at high speed operation.

• Journal of Plant Biology
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• v.30 no.3
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• pp.181-187
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• 1987

Copper inhibited PSII-mediated O2 evolution (H2OlongrightarrowDCIP, H2OlongrightarrowSiMo) but not PSImediated O2 uptake(DCIP. Asc.longrightarrowMV) in isolated Chinese cabbage chloroplasts. Copper toxicity on PSII-mediated O2 evolution was higher at alkaline condition than at acidic condition and was inhanced by light illumination after copper treatment. The increased toxicity by light illumination was not recovered by subsequent dark treatment. The inhibitory effect of copper on H2OlongrightarrowDCIP reaction was higher than that on H2OlongrightarrowSiMo reaction. This result suggests that there may be another inhibitory site of copper on PSII other than water oxidizing side of PSII.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.77-80
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• 2006

Graft copolymerized polycarboxylate(PC)-type superplasticizers(PCs) which have carboxylic acid with $\pi$ bond among the molecular structure and polyethyleneglycol methyl ether methacrylate(PMEM) were synthesized by free radical reaction and investigated the chemical structure, polymerization condition, and physical and chemical properties. Also, the effects of PCs in the dispersion, adsorption and hydration of cement were evaluated. As the molecular weight of graft chain decreases, the adsorption amount on cement particles increased. It was advantageous for the flow to reduce molar ratio, the lower the side bone molecular weight, and increase the molar ratio, the larger the side bone molecular weight. The hydration reaction speed was highly delayed at day 1, due to increase in molar ratio and reduction in side bone molecular weight, but it was recovered in the days after.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.98-103
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• 2012

One of the problems in the grinding process using the machining center(MC) with a small diametric wheels is machining error due to decrease of the quill diameter. In this thesis, side-cut grinding is performed with a vitrified bonded CBN wheel on the machining center to establish the basis of the grinding using MC. The grinding force and machining error are investigated experimentally for the change of the machining condition. It is possible to estimate the machining performance by the ratio of the setting depth of cut and actual depth of cut. In addition, the relation between normal grinding force and machining error is presented by the experimental formula.

• 한국데이터정보과학회:학술대회논문집
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• 2002.06a
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• pp.51-73
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• 2002

Empirical likelihood ratio method is a new technique in nonparametric inference developed by A. Owen (1988, 2001). Sometimes empirical likelihood has difficulties to define itself. As such a case in point, we discuss the way to define a modified empirical likelihood for the location of symmetry using well-known points of symmetry as a side conditions. The side condition of symmetry is defined through a finite subset of the infinite set of constraints. The modified empirical likelihood under symmetry studied in this paper is to construct a constrained parameter space $\theta+$ of distributions imposing known symmetry as side information. We show that the usual asymptotic theory (Wilks theorem) still hold for the empirical likelihood ratio on the constrained parameter space and the asymptotic distribution of the empirical NPMLE of difference of two symmetric points is obtained.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.378-383
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• 2005

The performances of side channel type regenerative blowers were evaluated by the blower performance test, 1-D performance prediction and CFD. The performance prediction method was modified using the results of the performance test and CFD and applied to the design of the new regenerative blowers. The major geometric parameters such as channel height, channel area and expansion angle were decided from the performance prediction method for the improved models and the predicted results were compared with CFD and experimental data. Both of the modified models showed improved efficiency at the operating condition. Especially, model3 could be possible to reduce operating rotating speed, that is benefit to noise performance, because of the high head performance at the design point. The CFD results showed that the performance of the regenerative blower was influenced by the secondary circulatory flow in the channel.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.296-299
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• 2002

The precision blanking of thin sheet metal is important process on production of precision electronic machine parts such as IC leadframe. In the blanking process, the factors that friction coefficient, tool clearance, material properties are the most important factors in the precision blanking process, because these factors affect the sheared face of product, side forces to punch during blanking process and surface condition after blanking process. So, many investigations have been performed. But, the former studies did not take up the characteristic of material. In this paper, in order to investigate the characteristic of blank, such as K(strength coefficient) and n(strain hardening coefficient), on the sheared face of blank and the side force to punch, FE-simulation has been analyzed by means of DEFORM-2D. To obtain input Parameters on FE-simulation, tensile and friction test has been done.

• Journal of Sensor Science and Technology
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• v.13 no.3
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• pp.207-212
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• 2004

We have investigated the optical characteristics of a directional coupler made of a side-polished polarization maintaining fiber in contact with a multimode planar waveguide and its applications as sensors. A device structural condition to achieve the polarization insensitive wavelength response has been presented. The fabricated devices revealed a superior immunity to the bending and the deformation of PM fibers in the input section. It is experimentally shown that the proposed device is suitable for a remote fiber sensor.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.6 no.2
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• pp.110-119
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• 1994

Three dimensional characteristics of fluid flow and heat transfer have been studied numerically around the latent heat storage vessel which was applied to the practical ice-storage system. The result obtained indicates that the value of frictional coefficient decreases with decrease of baffle width. For the baffle spacing. $S/H_D=9.375$, baffle height. $H/H_D=0.5$ and various pressure drop, average Nusselt numbers in heat transfer surface are much dependent on the width of side baffle and middle baffle. that is. Nu_m decreases with decrease of the width of middle baffle when the width of side baffle is 4.375, where as the optimum condition of side baffle for $Nu_m$ exists in the range of 3.5< $B_1/H_D$ <4.375 at the width of middle baffle, $B_2/H_D=6.875$.

• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.34-35
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• 1995

The unique feature of pervaporation is the mass transfer from a liquid phase to a vapor phase through a non-porous polymeric membrane. When a liquid mixture is brought into contact with a membrane at one side, it is sorbed into the membrane. Due to a driving force applied across the membrane, the sotbed liquid molecules permeate through the membrane and evaporate at the downstream side of the membrane. In pervaporation the permeated species are usually removed from the downstream side under a relatively low vapor pressure, for example by evacuation with a vacuum pump. As far as this condition is fulfilled, the evaporation step can be considered to be much faster than sorption or diffusion. Hence evaporation does not contribute to permselectivity. Therefore the separation by pervaporation results from the differences in the preferential sorption of the individual components of a mixture into the membrane together with the diffusion rates through the membrane. This postulation implies that both sorption and diffusion phenomena have to be accounted for to understand the physico-chemical nature of the pervaporation separation process.