• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.21-38
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• 2009

The use of multi scale modeling concepts and simulation techniques to study the destabilization of an ultrathin layer of oxide interface between a metal substrate and the surrounding environment is considered. Of particular interest are chemo-mechanical behavior of this interface in the context of a molecular-level description of stress corrosion cracking. Motivated by our previous molecular dynamics simulations of unit processes in materials strength and toughness, we examine the challenges of dealing with chemical reactivity on an equal footing with mechanical deformation, (a) understanding electron transfer processes using first-principles methods, (b) modeling cation transport and associated charged defect migration kinetics, and (c) simulation of pit nucleation and intergranular deformation to initiate the breakdown of the oxide interlayer. These problems illustrate a level of multi-scale complexity that would be practically impossible to attack by other means; they also point to a perspective framework that could guide future research in the broad computational science community.

• Journal of Engineering Education Research
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• v.23 no.4
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• pp.52-65
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• 2020

This study aims to find the major creative ideation patterns embedded in the commercially valuable patents in the mobile communication industry. For the purpose, we analyze 171 cases of the patent infringement lawsuit filed by Nokia in the United States. It is examined that what kind of TRIZ inventive principles and SIT thinking tools were applied to resolve technical contractions in each of the 171 cases respectively. Among the 40 inventive principles of TRIZ, 'feedback' principle was used mostly and 'division' principle the next. Among the 5 thinking tools of SIT, 'attribute dependency' mostly used, and 'division' the next. This suggests that what kind of inventive principles or thinking tools should be considered preferentially to resolve technical contradictions in practically important technical problems in the mobile communication industry.

• Korean Journal of Pharmacognosy
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• v.7 no.2
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• pp.85-93
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• 1976

Since cellulose is the only organic material that is annually replenishable in very large quantities, we must explore ways to utilize it as a source of energy, food and chemicals. For the utilization of this resource, it is first enzymatic hydrolyzed to glucose, then the glucose can be used as a food, converted single cell protein by microorganism, fermented to clean burning fuel and other chemicals. Cellulolytic enzyme, cellulase, consists of two or three major components, $C_1-cellulase$, $C_x-cellulase$ and ${\beta}-glucosidase$. $C_x-cellulase$ are fairly common but $C_1-cellulase$ are quite rare. Trichoderma viride is the best source of active cellulose, especially $C_1-enzyme$. Saccharification rate of cellulose in greatly influenced by the degree of crystallinity and extent of lignification. But by the pretreatment the substrate with cellulose swelling agent, delignifying reagent and physical treatment, the degree of saccharification is enhanced. Thus, glucose syrups of 2 to 10% concentration are realized from milled newspaper. The enzymatic hydrolysis of such energy rich material, such as cellulose, to glucose is technically feasible and practically achievable on a very large scale.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.3
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• pp.118-126
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• 2010

The automated mechanical transmission(AMT) is composed of electronic control management(ECM) and automatic shift gear(ASG). The AMT has advantages which are high efficiency of manual transmissions(MT) and offer operation convenience similar to automatic transmissions(AT). However, it has defects that are the torque gap during gear shift transients and shift time is long. To reduce such defects, it is necessary practically to evaluate error and characteristics as developing simulation model before the control algorithm is applied. In this paper, models are composed of vehicle model and AMT shift control model. Particularly AMT shift control model consists of main clutch management model (MCM) and shift control management model(SCM). The developed models were verified by comparing the simulated and experimental results under the same operational conditions. It can also be used to evaluate shift algorithm.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.843-850
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• 2005

In this study, simplified whirl flutter analyses using quasisteady aerodynamic theory have been Performed for a 2-DOF tiIt-rotor system with both pitch and Yaw motions of a rotor-nacelle. The present dynamic system consists of the rotor (propeller) , forming the gyroscopic and aerodynamic element, supported horizontally by a pylon that is pivoted at some wing attachment point. Several design parameters for rotor-nacelle system are considered to practically investigate the effects of whirl flutter stability.

• Journal of KSNVE
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• v.9 no.3
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• pp.587-592
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• 1999

Piston slap is one of the sources producing engine block surface vibration and mechanical noise. To analyze piston slap-induced vibration, a realistic but simple model is proposed and verified experimentally. A piston is modeled by 3 degree of freedom system and an impact point between piston skirt and cylinder wall by 2 degree of freedom system. Numerical simulation estimates impact forces of piston in cylinder, and the engine block surface vibration response is predicted by the convoluton of the impact forces with measured impulse responses. Experimental verification on the predicted response has been also performed by using a commercial 4-cylinder diesel engine. the predicted and experimental vibration responses confirm that the suggested model is practically useful.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.652-657
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• 2000

In this paper, Firstly, it is shown that the high vibration source of piping system is the pulsation transmission of pipe line element, such as, orifice plate, valves and the control valve is a broad band source and the branch wall and the cavity have vortex frequency. Secondly, in order to decrese the high vibration of piping system, some practical Friction damper with high damping have been developed and its effectiveness is investigated as installing it at piping system practically.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1667-1674
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• 2000

A new method is proposed to measure the flow rate in a pipe by multiple measurements of acoustic pressure using a microphone array. It is based on the realization that variation in flow velocity affects the change in wave number. The method minimizes measurement random errors and sensor mismatch errors thereby providing practically realizable flow rate measurement. One of the advantages of the method is that it does not obstruct the flow field and can provide the time-spatial mean flow rate. Numerical simulations and experiments were conducted to verify the utility of this method.

• Biomolecules & Therapeutics
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• v.1 no.1
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• pp.20-25
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• 1993

DA-125, a new anthracycline derivative, shows significant anticancer activities. We conducted a study to examine the local irritating effect of DA-125 using mice and rabbits. In the skin test in mice, intradermal injection of 0.4 mg of DA-125, compared to a dosage of 0.2 mg of adriamycin, had weak irritating potentials to induce skin ulceration and erythematous induration. A dosage of 0.6 mg of DA-125 produced similar degree of lesions in perivascular irritation model to that of 0.2 mg of adriamycin, but the healing time was shorter in the case of mice treated with DA-125. In ocular irritation study in rabbit, the highest M.O.I.(mean ocular irritation index) of 0.5% DA-125 solution was 0.67, therefore DA-125 could be considered as a practically non-irritating anticancer agent. These results suggest that substitution of DA-125 for Adriamycin would reduces the possibility of outbreaks of local irritation and the severity of the lesions.

• Biomolecules & Therapeutics
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• v.2 no.1
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• pp.71-76
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• 1994

Anti-inflammatory and analgesic activities and skin irritation of piroxicam patch were investigated. Piroxicam patch increased the pain threshold in rat hind paw inflamed by carrageenan and inhibited writhing induced by acetic acid in mice. Piroxicam patch also inhibited the carrageenan-induced edema in rat hind paw as well as the increased vascular permeability induced by histamine in rats. In adjuvant arthritis of rats, piroxicam patch showed anti-inflammatory effects. Skin irritation of piroxicam patch was tested in Newzealand White rabbits and evaluated by Primary Irritation Index of Draize. The results from skin irritation test showed that piroxicam patch seemed practically non-irritating. The result from the present study indicates that piroxicam may be useful without serious side effects as anti-inflammatory analgesics in this patch form.