• Journal of the Korean Ceramic Society
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• v.20 no.2
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• pp.166-172
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• 1983

In this study the sillicon-alloyed isotropic pyrolytic carbon was deposited in the tumbling bed from the pyrolysis of propane and silicon tetrachloride and investigated whether the silicon-alloyed isotropic pyrolytic carbon deposited in this study was usable as bionaterial or not. The silicon-allyed isotropic pyrolytic carbon was varied by controlling the process variables such as propane con-concentration and the argon flow rate flowing in to the silicon tetrachloride bubbler at a fixed reaction bed tempera-ture of 120$0^{\circ}C$ a rotation of reaction tube of 40 rpm a bed particle weight of 7.5 g and a total flow rate of 21/min; the propane concentration was varied from 10 to 70 and the argon flow rate flowing into the silicon tetrachloride bubble from 0 to 1000 cc/min. The results show that the silicon-alloyed isotropic pyrolytic carbon was obtained at all conditions investigated, . And then the alloyed silicon content is rangion from 7 to 14.5 wt%. The density and deposition rate of deposited silicon-alloyed isotropic carbon increased axxording to silicon content and propane concentration. And the apparent crystal-size(Lc) of pyrolytic carbon is not changed with silicon content. The density and apparant crystallite size are respec-tively in the range of 1.94 to 2.06 and 20 to 25$\AA$ It is shown that the silicon-alloyed isotropic pyrolytic carbon ob-tained in this experiment is usable as biomaterial.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.34-35
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• 2008

We investigated the effects of Pt nano electrodeposits on the corrosion of carbon substrate in an acidic solution. The electrodes for experiments were prepared by electrodepositing Pt on carbon substrate in a solution of 5 mM $H_2PtCl_6$ and 0.5 M $H_2SO_4$ using pulse deposition technique. In cyclic voltammograms for the carbon electrodes with and without Pt nano electrodeposits, total anodic current including both currents from oxygen evolution reaction and carbon corrosion increased abruptly above a critical potential. In addition, the critical potential of the carbon electrodes with Pt nano electrodeposits was lower than that of bare carbon electrode. This phenomenon was more prominent at $75^{\circ}C$ than $25^{\circ}C$. In potentiostatic experiments, the current transients and the corresponding power spectral density increased with increasing the applied potential for the electrodes. Furthermore, the current transients for the carbon electrodes with Pt nano electrodeposits were much higher than those for the bare carbon substrate. This indicates that the corrosion of carbon substrate can be highly accelerated by Pt nano electrodeposits.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1595-1597
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• 2003

This paper presents the deposition of ${\mu}c$-Si:H thin-film and fabrication of a solar cell by VHF-PECVD method. The ${\mu}c$-Si:H thin films and pin-type solar cells are fabricated using multi-chamber cluster tool system. A 7.4% conversion efficiency was achieved from ${\mu}c$-Si:H thin film solar cells with total thickness less than $5{\mu}m$. The physical characteristic was measured by Raman spectroscopy, Solar cell characteristic was measured under AM1.5 illumination.

• Journal of Biosystems Engineering
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• v.29 no.1
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• pp.21-28
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• 2004

Spraying is one of the most efficient methods for pesticide and insecticide control. Generally, orchard sprayers(aircarrier sprayer) are used for such applications. However, when an orchard sprayer is used, only 20% of total amount of spray deposits on the target. The rest of spray are not only wasted but are also potential sources of environmental pollution. The research far the development of electrostatic spraying system for orchard sprayer was conducted to develop the new pesticide application technology for the reduction of environmental pollution and f3r the production of safe agricultural products. The spray characteristics for nozzles with the different charging methods were tested and the effect of electrostatic charge was analyzed, in the laboratory experiments. The results of this study indicate that the capacitive type of electrostatic spraying nozzle exhibits a large current deposition of water sprays on the sample target. The covering area ratio by conventional spraying system was 10.2%, while that of electrostatic sprays with pulse induction charging method gave the increased covering area ratio by 4.3 times.

• Transactions on Electrical and Electronic Materials
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• v.13 no.1
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• pp.27-30
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• 2012

This paper proposes a micro gas sensor for measuring $H_2S$ gas. This is based on a $SnO_2$-CuO multi-layer thin film. The sensor has a silicon diaphragm, micro heater, and sensing layers. The micro heater is embedded in the sensing layer in order to increase the temperature to an operating temperature. The $SnO_2$-CuO multi layer film is prepared by the alternating deposition method and thermal oxidation which uses an electron beam evaporator and a thermal furnace. To determine the effect of the number of layers, five sets of films are prepared, each with different number of layers. The sensitivities are measured by applying $H_2S$ gas. It has a concentration of 1 ppm at an operating temperature of $270^{\circ}C$. At the same total thickness, the sensitivity of the sensor with multi sensing layers was improved, compared to the sensor with one sensing layer. The sensitivity of the sensor with five layers to 1 ppm of $H_2S$ gas is approximately 68%. This is approximately 12% more than that of a sensor with one-layer.

• Journal of the Korea Safety Management & Science
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• v.3 no.4
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• pp.53-63
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• 2001

The individual rotten water purification tank recently discharges wastewater and sewage through the outlet without purification ability. The outlet water and affiliated water purification tank with microorganism cultivator tank cultivates microorganism and then drops the value BOD, COD of sewage and discharges the quality of water into the outlet. The blower and water pump operating continuously prompts the waste of energy and deterioration of equipment. Each room of deposition tank, foaming tank, microorganism cultivator tank is equipment with the sludge detection senses so it can detect the density of each room. The power-drive plant of the blower and water pump which are the system cultivating the microorganism must be made as fuzzy controlization (If the sludge amount of each room become higher, the rate of operation of blower and water pump must heighten, on the contrary, in case of row sludge amount, the total handling amount and microorganism handling amount of each room of control. Tank reducing the rate of operation must be DB. At present, the blower amount in proportion to the sludge and oxyzen demanding amount has to control. Each room mus be checked outlet level of the outlet, also each room must flow backward discharge materials, and must operate feed-back control until we want to be come as a below value of BOD/COD(10PPM ; KS).

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.134-137
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• 2019

In this paper, the data retention characteristics were analyzed to find out the thickness effect on the trap energy distribution of silicon nitride in the silicon-oxide-nitride-oxide-silicon (SONOS) flash memory devices. The nitride films were prepared by low pressure chemical vapor deposition (LPCVD). The flat band voltage shift in the programmed device was measured at the elevated temperatures to observe the thermal excitation of electrons from the nitride traps in the retention mode. The trap energy distribution was extracted using the charge decay rates and the experimental results show that the portion of the shallow interface trap in the total nitride trap amount including interface and bulk trap increases as the nitride thickness decreases.

• Advances in materials Research
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• v.2 no.4
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• pp.181-193
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• 2013

Description and theory of spin coating technique has been elaborately outlined and a spin coating machine designed and fabricated using affordable components. The system was easily built with interdisciplinary knowledge of mechanics, fluid mechanics and electronics. This equipment employs majorly three basic components and two circuit units in its operation. These include a high speed dc motor, a proximity sensor mounted at a distance of about 15 mm from a reflective metal attached to the spindle of the motor to detect every passage of the reflective metal at its front and generate pulses. The pulses are transmitted to a micro-controller which process them into rotational speed (revolution per minute) and displays it on a lead crystal display (LCD) which is also a component of the micro-controller. The circuit units are a dc power supply unit and a PWM motor speed controlling unit. The various components and circuit units of this equipment are housed in a metal casing made of an 18 gauge black metal sheet designed with a total area of 1, $529.2cm^2$. To illustrate the use of the spin-coating system, ZnO sol-gel films were prepared and characterized using SEM, XRD, UV-vis, FT-IR and RBS and the result agrees well with that obtained from standard equipment and a speed of up to 9000 RPM has been achieved.

• Atmosphere
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• v.29 no.2
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• pp.227-239
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• 2019

This paper reviews various bulk-type cloud microphysics parameterizations (BCMPs). BCMP, predicting the moments of size distribution of hydrometeors, parameterizes the grid-resolved cloud and precipitation processes in atmospheric models. The generalized gamma distribution is mainly applied to represent the hydrometeors size distribution in BCMPs. BCMP can be divided in three different methods such as single-moment, double-moment, and triple-moment approaches depending on the number of prognostic variables. Single-moment approach only predicts the hydrometeors mixing ratio. Double-moment approach predicts not only the hydrometeors mixing ratio but also the hydrometeors number concentration. Triple-moment approach predicts the dispersion parameter of hydrometeors size distribution through the prognostic reflectivity, together with the number concentrations and mixing ratios of hydrometeors. Triple-moment approach is the most time expensive method because it has the most number of prognostic variables. However, this approach can allow more flexibility in representing hydrometeors size distribution relative to single-moment and double-moment approaches. At the early stage of the development of BMCPs, warm rain processes were only included. Ice-phase categories such as cloud ice, snow, graupel, and hail were included in BCMPs with prescribed properties for densities and sedimentation velocities of ice-phase hydrometeors since 1980s. Recently, to avoid fixed properties for ice-phase hydrometeors and ad-hoc category conversion, the new approach was proposed in which rimed ice and deposition ice mixing ratios are predicted with total ice number concentration and volume.

• Journal of Sensor Science and Technology
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• v.28 no.1
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• pp.23-29
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• 2019

A copper tetracumylphenoxy phthalocyanine (CuPccp) thin film was formed on an organic insulator film by Langmuir-Blodgett (LB) deposition for gas sensor fabrication. To increase the reproducibility of film transfer, stearyl alcohol was used as a transfer promoter. The structural properties of the CuPccp layers were optically monitored through attenuated total reflection and polarization-modulated ellipsometry techniques. The average thickness of a single layer of the CuPccp LB film was measured to be 2.5 nm. Despite the role of the transfer promoter, the stability of the layer transfer was not sufficient to ensure homogeneity of the LB film. This was probably due to the presence of aggregates in the molecular structure of the CuPccp LB film. Nevertheless, copper phthalocyanine polymorphism can be greatly suppressed by the LB arrangement, which appears to contribute to the improvement of electrical conductivity. The p-type semiconductor characteristics were confirmed by Hall measurements from the CuPccp LB films.