• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.6
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• pp.401-415
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• 1989

A simple but accurate analytical model for the lateral channel electric field in gate-offset structured Lightly Doped Drain MOSFET has been developed. Our model assumes Gaussian doping profile, rather than simple uniform doping, for the lightly doped region and our model can be applied to LDD structures where the junction depth of LDD is not identical to the heavily doped drain. The validity of our model has been proved by comparing our analytical results with two dimensional device simulations. Due to its simplicity, our model gives a better understanding of the mechanisms involved in reducing the electric field in the LDD MOSFET. The model shows clearly the dependencies of the lateral channel electric field on the drain and gate bias conditions and process, design parameters. Advantages of our analytical model over costly 2-D device simulations is to identify the effects of various parameters, such as oxide thickness, junction depth, gate/drain bias, the length and doping concentration of the lightly doped region, on the peak electric field that causes hot-electron pohenomena, individually. Our model can also find the optimum doping concentration of LDD which minimizes the peak electric field and hot-electron effects.

• Journal of Welding and Joining
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• v.6 no.4
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• pp.16-26
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• 1988

The effect of carbon content on hot cracking of welded carbon steel was investigated Eight steel plates whose carbon content range from 0.02 to 0.23 percent were welded by autogeous gas tungsten are process. Constant strain was applied to the hot crack test specimen under the strain rate of 0.15 mm per second during welding. The hot cracking susceptibility ws high in the rnage of 0.02-0.05 and 0.12-0.23 percent carbon contents. The critical carbon content immune to hot cracking is in the range from 0.07 to 0.12 percent carbon. By electron probe microanalyser, amanganese segregation was not seen significantly in the whole carbon range. But segregation of silicon was higher in the region of low carbon contents. However, sulphur was segregated remarkably in the region betwen 0.18 and 0.23 percent carbon by peritectic reaction. Very smal lamount of dnedritic structure was observed in the region from 0.02 to 0.05 percent carbon by peritectic reaction. Very small amount of dendritic structure was observed in the region from 0.02 to 0.05 percent carbon but the predominant solidification structure was smooth by cellular growth. The higher the carbon content is, the more the columnar dendritic structure was observed.

• The Korean Journal of Food And Nutrition
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• v.12 no.5
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• pp.478-483
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• 1999

This study was conducted to investigate functional properties of 70% acetone extract in different parts of two potato varieties. 'Superior' and 'Atlantic' potato were processed by following method. Potatoes are washed, peeled, sliced and steamed before hot air drying for flesh and peel powder. Hunter's L and b values of flesh powder from blanched 'Superior' potato were higher than flesh powder from fresh 'Superior' potato. Discoloration of 'Superior' potato was inhibited by steam blanching. Contents of total polyphenol and chlorogenic acid in the 70% acetone extract of 'Superior' potato were higher than those of 'Atlantic' potato paticularly in the blanched flesh and peel. But flavonoid was not detected in flesh extract. The phenolic concentration was not decreased by the heat treatment. The nitritescavenging and electron donating ability was greatest at the tuber peel including the skin and cortex tissue 1mm beneath the skin. From the above results browning reaction and polyphenol contents in different parts of potato slices were dependent on cutivars. Peels contained more polyphenols than those from the flesh. The results indicate that potato peel extract of steam blanched plus hot air dried potato tuber showed the effectiveness as a natural nitrite scavenger and antioxidant.

• Proceedings of the Korean Vacuum Society Conference
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• 2004.02a
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• pp.58-58
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• 2004

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.3
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• pp.71-75
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• 2009

Cotton waste is usually used for cultivating agaric mushroom after outdoor fermentation for a few months. Electron beam was used to break down the polymer chaims of cotton waste for increasing low molecular weight soluble sugars, which may enhance the agaric mushroom cultivation. By increasing electron beam radiation, alpha cellulose content of the cotton waste was decreased while beta cellulose content and hot water solubles were increased. Electron beam radiation over 240 kGy on cotton waste caused significant increase of mushroom yield without lowering mushroom quality.

• Applied Microscopy
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• v.48 no.4
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• pp.126-127
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• 2018

Carbon has numerous allotropes and various crystalline forms with full dimensionalities such as diamond, graphite, fullerenes, and carbon nanotubes leading a wide range of applications. Since the emerge of graphene consisting of a single atomic layer of carbon atoms, a fabrication of all-carbon-based device with combination of one-, two-, and three-dimensional carbons has become a hot issue. Here, we introduce an ultimate one-dimensional carbon atomic chain. Carbon atomic chains were experimentally created by removing atoms from monolayer graphene sheet under electron beam inside transmission electron microscope (TEM). A series of TEM images demonstrate the dynamics of carbon atomic chains over time from the formation, transformation, and then breakage.

• Korean Journal of Materials Research
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• v.16 no.7
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• pp.435-438
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• 2006

The hot pressing was employed to prepare Fe-doped $CoSb_3$ skutterudites and their thermoelectric properties were investigated. Single phase ${\delta}-CoSb_3$ was successfully obtained by the hot pressing under 60MPa at 773 K for 2 hrs. Iron atoms acted as electron acceptors by substituting cobalt atoms. Thermoelectric properties were remarkably improved by the appropriate doping. $Co_{0.7}Fe_{0.3}Sb_3$ was found as an optimum composition for the best thermoelectric property in this work.

• Journal of the Korean institute of surface engineering
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• v.39 no.3
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• pp.87-92
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• 2006

The characteristic of interface layer and the effect of bias voltage on the microstructure of c-BN films were studied in the microwave plasma hot filament C.V.D process. c-BN films were deposited on a high speed steel(SKH-51) substrate by hot filament CVD technique assisted with a microwave plasma to develop a high performance of resistance coating tool. c-BN films were obtained at a gas pressure of 20 Torr, vias voltage of 300 V and substrate temperature of $800^{\circ}C$ in $B_2H_6-NH_3-H_2$ gas system. It was found that a thin layer of hexagonal boron nitride(h-BN) phase exists at the interface between c-BN layer and substrate.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.4
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• pp.129-135
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• 1996

In this paper, the hot carrier effect and device degradation of deep submicrometer SC-PMOSFETs have been measured and characterized. It has been shown that the substrate current of a 0.15$\mu$m PMOSFET increases with increasing of impact ionization rate, and the impact ionization rate is a function of the gate length and gate bias voltage. Correlation between gate current and substrate current is investigated within the general framework of the lucky-electron. It is found that the impact ionization rate increases, but the device degradation is not serious with decreasing effective channel length. SCIHE is suggested as the possible phusical mechanism for enhanced impact ionization rate and gate current reduction. Considering the hot carrier induced device degradation, it has been found that the maximum supply voltage is about -2.6V for 0.15$\mu$m PMOSFET.

• Korean Journal of Materials Research
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• v.16 no.6
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• pp.382-385
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• 2006

Ni-doped $CoSb_3$ was prepared by the hot pressing, and its doping effects on the thermoelectric properties were investigated. Single phase ${\delta}-CoSb_3$ was successfully obtained by encapsulated induction melting and the subsequent heat treatment at 773 K for 24 hrs, followed by the hot pressing under 60 MPa at 773 K for 2 hrs. Nickel atoms acted as electron donors by substituting cobalt atoms. Thermoelectric properties were remarkably improved by the Ni doping.