• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.706-709
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• 2002

We investigated the effect of lithium 8-hydroxyquinolinolatolithium (Liq) as an electron injection layer on the performance of organic light emitting devices (OLEDs) and optimized the device efficiency by varying thickness of Liq layer. The device with 1nm Liq layer showed significant enhancement of the device performance and device lifetime. We also compared $Znq_2$ and LiBBOX with Liq as an electron injection layer.

• Laser Solutions
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• v.18 no.3
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• pp.6-8
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• 2015

Finishing process includes deburring, polishing and edge radiusing. It improves the surface profile of specimen and eliminates the alien substance on surface. Deburring is the elimination process for debris of edges. Polishing lubricates surfaces by rubbing or chemical treatment. There are two types for electron finishing. The one is using pulse beam. The other is using the convergent and scanning electron beam. Pulse type device appropriates the large area process. But it does not control the beam dosage. Scanning type device has advantages for dosage control and edge deburring. We design the convergence and scan type. It has magnetic lenses for convergence and scan device for scanning beam. Magnetic lenses consist of convergent and objective lens. The lenses are designed by the specification(beam size and working distance). In this paper, we evaluate the convergence performance by pattern process. Also, we analysis the results and important factors for process. The important factors for process are beam size, pressure, stage speed and vacuum. These results will be utilized into systematizing pattern shape and the factors.

• Journal of the Semiconductor & Display Technology
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• v.10 no.4
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• pp.107-112
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• 2011

This paper is for improving the RF frequency performance of a fabricated 100nm ${\Gamma}$-gate MHEMT, scaling down vertically for the epitaxy-structure layers of the device. Hydrodynamic simulation parameters are calibrated for the fabricated MHEMT with the modulation-doped $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}$As heterostructure grown on the GaAs substrate. With these calibrated parameters, simulations for the vertically-scaled epitaxial layers of the device are performed and analyzed for DC/RF characteristics, including the quantization effect due to the thickness reduction of InGaAs channel layer. A newly designed epitaxy-structure device shows higher extrinsic transconductance, $g_m$ of 1.556 S/mm, and higher frequency performance, $f_T$ of 222.5 GHz and $f_{max}$ of 849.6 GHz.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.28-36
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• 2009

The majority of fixed shading devices are installed in the exterior of a building in order to dissipate the heat absorbing from the sun and to prevent the direct sunlight. In designing external shading devices for windows, many requirements must be considered simultaneously; solar geometry, optimum energy performance, multi-purpose usage and design factors etc.. In order Lo satisfy these requirements, we suggests the folding shading device and its optimum design methodology. Also we analyzed the thermal performance using the IES_VE program according to various operating modes and compared with existing shading devices. The results show that proposed device reduce about $1.90{\sim}22.40%$ in cooling load and about $1.09{\sim}24.22%$ in heating load in comparison with existing ones.

• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.47-54
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• 1993

This paper describes briefly the effect of ultrasonic fuel supply device on the performance of four stroke cycle gasoline engine. Experiments were carried out to clarify the effect of ultrasonic fuel supply device on the engine output, traveling fuel consumption ratio, exhaust emissions. The results were obtained as follows: 1.Engine output was increased 9-14% in comparison with that of the conventional injector. 2.Travelling fuel consumption ratio was improved 17-29% in comparison with that of the conventional injector. 3. CO, HC exhaust emissions was decreased compared to the value of the conventional injector. 4.Fuel consumption ratio in highway driving test was improved about 10% in comparison with that of the conventional injector.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.385-388
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• 2009

We have investigated the effect of the device structure on the performance of polycrystalline ZnO TFT and amorphous AZTO TFT with top gate and bottom gate structure. While the mobility of both TFTs showed relatively similar value in a top and bottom gate structure, bias stability was quite different depending on the device structure. Top gate TFT showed much less Vth shift under positive bias stress compared to that of bottom gate TFT. We attributed this different behavior to the defects formation on the gate insulator induced by energetic bombardment during the active layer deposition in a bottom gate TFT. We suggest the top gate oxide TFT would show more stable behavior under the Vgs bias.

• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.125-131
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• 2003

In recent years, the Korean Army made use of fork-lifters or conveyors when loading and/or unloading military material in order to prevent accidents and to promote efficiency of military material handling activities. However, in troops smaller thin battalions, manual material handling activities are still committed for many reasons. In this thesis, a brand new loading/unloading device for efficient military material handling or manual workers was developed, and its validation study was conducted through objective assessment based on electromyography, subjective assessment based on Body-Map technique developed by Corlett and Bishop, and finally work performance comparison. The results of EMG analysis showed that muscular workload improved by 24% when using the device compared to manual work without the device, and complain of each body part was remarkably reduced. In addition, remarkable effectiveness enhancement was observed in the work performance. Consequently, it could be concluded that ergonomic devices like one developed in this research should be studied further in the ergonomic sense as well as in the economical sense.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.407-412
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• 2002

A measurement device for gas concentration and flow rate using hot wire is developed for the utilization in industrial applications. The device has two cells of measuring and reference, and a bridge circuit is installed to detect electric current through the hot wire in the cells. An amplification of the signal and conversion to digital output are conducted for the on-line measurement with a personal computer. The flow rate of air and carbon dioxide gas is separately measured for the performance examination of the device. Also, the concentration of air-carbon dioxide and carbon dioxide-argon mixtures is determined for the same evaluation. The outcome of the performance test indicates that the accuracy and stability of the device is satisfactory for the purpose of industrial applications.

• Journal of Integrative Natural Science
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• v.12 no.1
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• pp.9-13
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• 2019

Recently, as the sleep disorder problem of modern people deepens, the interest towards quality of sleep is increasing. To increase the quality of modern people's sleep. This paper has suggested an LED lighting control system according to the sleep stage using PPG sensors of wearable devices. The pulse of the wrist radial artery was measured using a wearable device mounted with PPG sensor, which enables heart rate-measuring, and by using the point that heart rate lowers during stable sleep than non-sleeping, the LED lighting of indoors was controlled, which is the disturbing element when sleeping. For the performance evaluation, a 10-Fold cross analysis was conducted for performance evaluation, and a result of an average accuracy 87.02% was obtained as a result. Therefore, the LED lighting control system according to the sleep stage using a wearable device of this paper is expected to contribute to raise the quality of the user's life.

• Journal of Electrochemical Science and Technology
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• v.8 no.4
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• pp.265-273
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• 2017

Solid-state alkaline water electrolysis is a promising method for producing hydrogen using renewable energy sources such as wind and solar power. Despite active investigations of component development for anion exchange membrane water electrolysis (AEMWE), understanding of the device performance remains insufficient for the commercialization of AEMWE. The study of assembled AEMWE devices is essential to validate the activity and stability of developed catalysts and electrolyte membranes, as well as the dependence of the performance on the device operating conditions. Herein, we review the development of catalysts and membranes reported by different AEMWE companies such as ACTA S.p.A. and Proton OnSite and device operating conditions that significantly affect the AEMWE performance. For example, $CuCoO_x$ and $LiCoO_2$ have been studied as oxygen evolution catalysts by Acta S.p.A and Proton OnSite, respectively. Anion exchange membranes based on polyethylene and polysulfone are also investigated for use as electrolyte membranes in AEMWE devices. In addition, operation factors, including temperature, electrolyte concentration and acidity, and solution feed methods, are reviewed in terms of their influence on the AEMWE performance. The reaction rate of water splitting generally increases with increase in operating temperature because of the facilitated kinetics and higher ion conductivity. The effect of solution feeding configuration on the AEMWE performance is explained, with a brief discussion on current AEMWE performance and device durability.