• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.102-104
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• 1996

The fabrication and analytical expression for the temperature dependent capacitance characteristics of inverted staggered hydrogenerated amorphous silicon thin film transistors(a-si :H TFT) from 303k to 363k were presented. The results show that the experimental capacitance-voltage characteristics at several temperatures are easily measured. Capacitance increased exponentially by gate voltage increase and decreased by temperature increase. C/C(max) ratio decreased at higher temperature, C/C(min) ratio increased at higher temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.825-826
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• 2008

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.271-284
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• 1999

As a semiconductor material for electronic devices operated under extreme environmental conditions, silicon carbides (SiCs) have been intensively studied because of their excellent electrical, thermal and other physical properties. The growth characteristics of single-crystalline 4H-SiC homoepitaxial layers grown by a thermal chemical vapor deposition (CVD) were investigated. Especially, the successful growth condition of 4H-SiC homoepitaxial layers using a SiC-uncoated graphite susceptor that utilized Mo-plates was obtained. The CVD growth was performed in an RF-induction heated atmospheric pressure chamber and carried out using off-oriented substrates prepared by a modified Lely method. In order to investigate the crystallinity of grown epilayers, Nomarski optical microscopy, Raman spectroscopy, photoluminescence(PL), scanning electron microscopy (SEM) and other techniques were utilized. The best quality of 4H-SiC homoepitaxial layers was observed in conditions of growth temperature 1500$^{\circ}C$ and C/Si flow ratio 2.0 of C3H3 0.2sccm & SiH4 0.3sccm. The growth rate of epilayers was about 1.0$\mu\textrm{m}$/h in the above growth condition.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.3
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• pp.353-360
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• 1999

An investigation made of the variations of angle of bias on the top of the sleeve cap curve line and calculated easing contraction ratio by capheights(A ; a,h$\times$5,/6) B: A, H/4 +4cm C:A.H/3 D: A.H/ 4+3cm E:AH/4+2cm, F: A,H/4+1cm, G: A,H/4, H:A,H/6, I:A,H/8) and the efects of easing contraction on the cap curve lines of sleeve A, D, G by easing stitch density with the gathering foot: sewing condition-lockstitch industrial machine stitch density(N1.0 ; 38stitches/3cm N1.5: 26stitches/3cm, N2.0 ; 19stitches/3cm, N2.5 ; 14stitches/ 3cm) The results obtained were as follows; 1) The variations of the angle of bias on the top of the sleeve cap curve line by cap heights can be done according to the angle balance (front; $\alpha$-$\beta$ back ; $\alpha$'- $\beta$') between the angle (front ;$\alpha$, $\beta$, back ; $\alpha$'- $\beta$') of bias of the two base-lines. 2) The higher cap height the more higher the calculated easing contraction ratio. 3) The lower the stitch density the higher easing contraction ratio. 4) The effects of easing contraction was that sleeve G was more than sleeve A, D.

• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.44-56
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• 1997

When sewage sludge is treated by cornposting, higher moisture content and lower C/N ratio on sewage sludge is problems. This paper project to alesolve two problems. The almost trends in run 3 of MC 70% are similar to these in run 1 and 4 of MC 65%. A retention time of the highest temperature (>50$\circ$C) and increase rate of temperature in run 3 are an affinity to these in run 4. Particularly, decrease rate of temperature in run 3 is slower than others and this data shows the more activity of thermal microbial in run 3 than that in others. C/N ratio trends in run 3 shows slow reaction in initial stage but, after 9 days, is similar to that in run 1 and 4. Carbon trends in each run are a similarity to C/N ratio trends. Temperature, MC, carbon and C/N ratio trends in run 5, whose C/N ratio is 15, show less microbial activity than that in run 6, whose C/N ratio is 20. But temperature increase of the beginning stage and pH of the final stage in run 5 are greater than that in run 6. Final MC and carbon content in run 5 and 6 have a similar values. That is, final MC in run 5 and 6 is 49.39% and 48.97% and final carbon content in each run is 25.15% and 22.20%. Expecially, a temperature increase and C/N ratio decrease rate of the beginning stage in run 5 are greater than these in run 6. This shows the shorter lag time in run 5 than lag time in run 6.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.590-595
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• 1994

Kimchi packed in PP tray was stored at $10^{\circ}C$ to investigate the effect of filling ratio on the quality changes. The quality of Kimchi studied were gas composition in the package, pH, titratable acidity, color, growth of lactic acid bacteria and sensory properties. As the filling ratio increased, there was more $O_{2}$ consumption and $CO_{2}$ evolution measured. Titratable acidity and pH were not significantly affected by the filling ratio. Color change of crushed Kimchi juice was also little affected by the filling ratio. During the storage, L and b values were decreased exponentially, but a value s remained constant. The growth of lactic acid bacteria and sensory scores showed no significant difference according to the filling ratio. Therefore, the filling ratio in packaging of Kimchi seemed to have little influence on the quality changes of Kimchi.

• Electrical & Electronic Materials
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• v.7 no.4
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• pp.281-288
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• 1994

According to spread volume of B(BiPbCuO) layer, composition ratio and each stage of sintering process, we studied stability of high Tc superconductor phase and generation and growth movement of superconducting phase. The dual layer composed of SrCaCuO and BiPbCuO compound were prepared to develop the Bi-2223 superconductor[108K] through interaction and diffusion during sintering process. The dual layer samples were sintered at 830.deg. C for 0-210 hours. From the result, the optimum conditions were : spread volume(A:B=1:0.6), sintering time(210h) and composition ratio(A:S $r_{2}$C $a_{2}$C $u_{2}$- $O_{x}$, B:B $i_{1.9}$P $b_{0.5}$C $u_{3}$ $O_{y}$) at 830.deg. C.. C.C.C.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.302-305
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• 2007

In recent years, many researches on new storage media with high capacity and information are developing. For manufacture of optical storage with high capacity, the injection molding process is generally used. In order to increase the filling ratio of the injection molding structure, the injection molding process required for high injection pressure, packing pressure and temperature control of the mold. However, conventional injection molding process is difficult to increase the filling ratio using injection master with the range of several nanometers and high aspect ratio. In order to improve and increase filling ratio of nano-structure with high aspect ratio, the active temperature control of injection mold was used. Experimental conditions were used injection pressure, time and temperature. Consequently, by using the peltier device into injection mold, we carried out the efficient and active temperature control of mold at low cost.

• Journal of Power System Engineering
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• v.6 no.1
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• pp.43-49
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• 2002

This paper showed the study on the heat transfer into space by the aspect ratio of solar concentration absorber, and the purpose of this study was to obtain the optimum aspect ratio and tilt angle. The boundary conditions of a numerical model are assumed as follows : (1) The heat source is located at the center of absorber. (2) The bottom wall is opened and adiabatic. (3) The top, right and left walls are cooled wall. The parameters for the study are the tilt angles and the aspect ratio. The velocity vectors and isotherms were dense at wall side and the heat source. The mean Nusselt number had a maximum value at Ar=1:1 and ${\theta}=0^{\circ}$ and showed a low value as the tilt angles were increased.

• Journal of Nutrition and Health
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• v.28 no.8
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• pp.706-716
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• 1995

This study was undertaken to investigate the influence of age and dietary linolenic acid content and the linolenic acid/linoleic acid (LAN/LA) ratio on the brain lipid composition and membrane-bound enzyme, acetylcholinesterase(AchE) activities. AchE was selected as a test case for the relationship between cell lipid composition and cell membrane function. The male rats were fed diets with 0.2, 0.4, 0.6 of LNA/LA ratio within 8% LNA(H-LNA) or 4% LNA(L-LAN) of total fatty acid content for different feeding period(1, 4, 12 month). The fats used s source were sesame oil, perilla oil, soybean oil and beef tallow. The AchE activity of brain crude synaptosomal fraction was reduced with advancing age, showing 20-30% reduction in 12M compared with 1 M, and the P/C ratio was reduced in old rats. In 1 and 4 monthed rats, AchE activites was higher in H-LAN-0.2 and L-LNA-0.2 and 0.4 group. In accordance with rising of AchE activities was higher in H-LNA-0.2 and L-LNA-0.2 and 0.4 group. In accordance with rising of AchE activities, the PC/PE ratio increasedin those groups. Paricularly in L-LNA, the PC/PE ratio increased as the AchE activites for decline of membrane fluidity with increasing cholesterol and decreasing P/C ratio when rats were old. Also, AchE activity increaed with increasing PC/PE ratio which depended on the dietary LNA/LA ratio within each LNA content. Therefore, it is concluded that the lipid composition of cell membrane influenced the AchE activiteis, which was mediated by aging and the modification of dietary LNA/LA ratio.