• Tribology and Lubricants
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• v.33 no.5
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• pp.214-219
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• 2017

Abrasive fluidized bed machining (AFBM) is similar to general abrasive fluidized machining (AFM) in that it can perform polishing of the outer and inner surfaces of a 3-dimensional shape by the flow of particles. However, in the case of AFM, the shear force generated by the flow of the particles causes material removal, while in AFBM, the abrasive particles are suspended in the chamber to form a bed. AFBM can be used for deburring, polishing, edge contouring, shot peening, and cleaning of mechanical parts. Most studies on AFBM are limited to metals, and research on application of AFBM to plastic materials has not been performed yet. Therefore, in this study, we investigate the effect of rotating speed of the specimen and the air flow rate on the material removal characteristics during AFBM of polyacetal with a horizontal AFBM machine. The material removal rate (MRR) increases linearly with increase of the rotating speed of the main shaft because of the shear force between the particles of the fluidized bed and the rotation of the workpiece. The reduction in surface roughness tends to increase as the rotating speed of the main shaft increases. As the air flow rate increases, the MRR tends to decrease. At a flow rate of 70 L/min or more, the MRR remains almost constant. The reduction of the surface roughness of the specimen is found to decrease with increasing air flow rate.

• KSBB Journal
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• v.9 no.5
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• pp.443-449
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• 1994

Fermentation characteristics of Kluyveromyces fragilis CBS 1555 with Jerusalem artichoke juice, in extractive ethanol fermentation in aqueous two phase systems composed of polyethylene glycol 20000 (PEG) and crude dextran(Dx), were investigated as a function of initial sugar concentrations, concentrations of ethanol formed, or fermentation time. Both specific ethanol production rate increased with decrease in concentrations of PEG and Dx in two-phase systems. Without being related to the compositions of aqueous two-phase system, maximum specific cell growth rate and maximum specific ethanol production rate were showed in the initial sugar concentration fo $80g/\ell$ and $120g/\ell$, respectively. The inhibition effects of ethanol on specific cell growth rate and specific ethanol production rate decreased with decrease in PEG concentration and in the range of 2.5 to 5% Dx. Specific cell growth rate and specific ethanol production rate was fitted as an exponential function and a hyperbolic function, respectively, of the concentrations of ethanol formed. Overall ethanol productivity increased with increase in initial sugar concentrations, and also the required time for the maximum productivity was so. Ethanol production rate by the elapsed fermentation time showed the maximum value in the initial sugar concentration of $160g/\ell$.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.4
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• pp.50-57
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• 2009

This paper presents a new model-based macroblock layer rate control algorithm for low bit rate video coding which generates output bits corresponding to a target bit budget. The H.264 standard uses various coding modes and optimization methods to improve the compression performance, which makes it difficult to control the generated traffic accurately in low bit rate environments. In the proposed scheme, we first estimate MAD values of macroblocks in a frame and define a target remaining bits using the estimated MAD values before encoding each macroblock. If a difference between the target value and the actual value is greater than a threshold value, the quantization parameter is adjusted to decrease the difference. It is shown by experimental results that the new algorithm can obtain more than 66% decrease of the difference between the target bits and the resulting bits for a frame with the PSNR performance better than that of the existing rate control algorithm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.8
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• pp.604-611
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• 2008

Detailed analysis of NO formation routes and its contributions with strain rate in hydrogen/air flames were numerically investigated. LiG detailed reaction mechanism has been used for calculation, which is compared with experimental data in literature. It shows good agreement with experiment for both temperature and NO mole fraction. Three routes have been found important for NO formation in hydrogen flames. These are the Thermal route, NNH route and $N_2O$ route. Strain rate were varied to discuss the $EI_{NO}$ reduction trend in hydrogen nonpremixed flames, which are analyzed by each NO formation routes. As a result, as the strain rate increase, $EI_{NO}$ decrease sharply until strain rate $100s^{-1}$ and decrease slowly until strain rate $310s^{-1}$ again, after that $EI_{NO}$ keeps nearly constant. It can be identified that $EI_{NO}$ trend with the strain rate is well explained by a combination of variation of production rate of above Thermal, NNH and $N_2O$ route. Also result of Thermal-Mech. that includes only thermal NO reaction is compared with those of Full-Mech. As a result, It can be identified that there was difference between the two results of calculation. It is attributed to result that Thermal-mech did not consider contributions of NNH and $N_2O$ route. From these result, we can conclude that NOx emission characteristics of hydrogen nonpremixed flames should consider contributions of above three routes simultaneously.

• The Korean Journal of Pharmacology
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• v.16 no.2 s.27
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• pp.1-7
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• 1980

As it has been reported that morphine induce antidiuresis, and antinatriuresis along with decrease in renal hemodynamics when given intracerebroventricularly[ivt], the renal action of nalorphine, a partial antagonist of morphine action, and its influence upon the morphine action were investigated in this study. $10{\mu}g/kg$ of nalorphine given into the lateral ventricle of the rabbit brain tended to decrease renal plasma flow and glomerular filtration rate and increase the reabsorption of free water in the tubules. $100{\mu}g/kg$ ivt significantly decreased urine flow rate and increased free water reabsorption, and tended to increase electrolyte excretion in spite of decrease in renal plasma flow and glomerular filtration, suggesting that ADH also involved in the antidiuresis. Morphine hydrochloride, $10{\mu}g/kg$, ivt, produced marked decrement in renal hemodynamics along with decreased excretions of sodium, potassium and water, and these morphine actions were alleviated by nalorphine given 20 min later. The natriuretic action of ivt nalorphine manifested itself uninfluenced by the morphine. These observations indicate that nalorphine ivt produces renal actions similar to those of morphine, though less potent, and that it can antagonize the latter action. It is suggested that morphine influences renal hemodynamics through nerve by stimulating the 'morphine receptor' in the brain, whereas nalorphine liberates ADH by the agonistic action on the 'nalorphine receptor'.

• Journal of The Korean Society of Integrative Medicine
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• v.1 no.1
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• pp.11-22
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• 2013

Purpose : The purpose of this study was to investigate the effects of music intervention upon lighting on stress. Method : The participants 60 college students, were divided three groups. Two groups were apply each music and bright lighting(bright lighting groups) and music and dark lighting(dark lighting groups) during 13minutes at Snozelen and the other group was control group. Each groups were assessed stress resistance, activity of parasympathetic nerve, activity of sympathetic nerve, balance of ANS, physical arousal by EKG of CANS 3000, at before and after other each intervention. The analyses were performed using version of SPSS 17. Result : The change rate of bright lighting group was showed statistically significant decrease in stress resistance compared to control group. And the change rate of dark lighting group was showed statistically significant decrease in resistance stress, activity of parasympathetic nerve, and balance of ANS compared to control group and statistically significant increase in stress resistance and activity of parasympathetic nerve compared to bright lighting group. Conclusion : The results of this study indicate that music intervention on dark lighting is more effective on decrease of stress than application of bright lighting and general lighting.

• Journal of the Korean Society of Safety
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• v.14 no.4
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• pp.114-119
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• 1999

When NaOCl was generated and put into sea-water cooling machine in order to overcome the biological hindrances against sea-water cooling machine, it was converted into metallic ion, particularly Ca and Mg, as a hydrate in sea-water and is to stick to electrolyte as a side reaction. This phenomena make the distance between the electrolytes narrow to decrease the flow rate, which induces the local vortex flow which erodes the pole plate. Moreover, this increases the resistance of the electrolyte as well as voltage to decrease the electrolytic efficiency, which has curtailed a chlorine yield and caused a pole plate cut. We are able to overcome these problems by chemical cleaning and intend to extend the life-time of electrolyte and to increase output of the sea-water electrolysis facilities by studying optimal policy regarding chemical cleaning of electrolytic cell. Cleaning time of electrolytic facilities is determined when both increase in electrolytic efficiency and decrease in pole-plate voltage are 10%. At this time as operating current of electrolytic facilities is high, operating time is diminished. Whereas, parameter of end point determination according to cleaning is Mg ionic concentration in solution. When we use Cleaner as a 7wt% HCl, cleaning time is about 80min proper. We are able to maintain pole plate performance by protecting against pole plate cut by means of electrolytic by-product, improve operating rate of facilities, and cut down on maintenance expenditure after acidic cleaning.

• The Journal of Korean Physical Therapy
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• v.25 no.5
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• pp.252-259
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• 2013

Purpose: The aim of this study was to evaluate the effect of progressive body weight decrease combined with increasing level of overground walking speed training for patients with chronic stroke. Methods: Eighteen subjects with chronic stroke were composed of the control group (5% body weight support combined with increasing speed training) and the experimental group (progressive body weight decrease with increasing speed training); three sets, three times per week over a period of four weeks. Results: Significant differences in terms of comfortable gait speed (CGS) and the rate of change of CGS were observed between the control and experimental groups (p<0.05). However, no significant difference in the dynamic gait index was observed between the control and experimental groups (p>0.05). A significant difference in the 6 minute walking test (6MWT) was observed for the experimental group, and a significant difference in the rate of change for the 6MWT was observed between the control and experimental groups (p<0.05). Conclusion: The progressive body weight decrease combined with increasing in level of overground walking speed training may be a better and more effective method for community walking and reintegration.

• Plant Journal
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• v.9 no.2
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• pp.46-50
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• 2013

When four operation parameters are adjusted, the temperature of reheater steam is around the designed operator temperature and the decrease of reheater spray flow rate is achieved. As a result, the decrease of thermal efficiency also can be prevented. To keep the reheater exit temperature on the designed value and decrease the use of reheater spray flow rate, the control of four operation parameters is considered and applied in the operation of a thermal power plant.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.172-178
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• 2008

An object of this study is to confirm performance characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air flow rate and the ${\Delta}T_c$ decrease ratio of the intercooler were measured in a experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. To investigate energy separation characteristics of the vortex tube, the measured turbo pressure was applied to the vortex tube inlet and the ${\Delta}T_c$ decrease ratio was compared with one of the intercooler in the cold air mass flow ratio similar to the intake air flow rate of the experimental engine. From the results, we found that the energy separation ratio is increased according to of the inlet pressure and the ${\Delta}T_c$ decrease ratio of the vortex tube apparatus is higher than one of the intercooler at low engine speed and engine load of medium and low.