• International Journal of Precision Engineering and Manufacturing
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• v.4 no.4
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• pp.25-31
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• 2003

A computer simulation model for investigating a two-dimensional (2-D) rounding mechanism in a centerless grinding process is described. This model includes the interference phenomena and the concept of machining elasticity. Since initial contact points are used as a reference, the result of this simulation is not affected by the location of the reference circle center and the radius of the reference circle. Also, details of the machining factor are studied by using process variables (grinding wheel speed, wheel specification, workpiece speed, dressing condition, etc.). The effect of the threshold grinding force on the size of ground workpiece is investigated. For the verification of this method, simulation results are compared with the experimental work.

• Natural Product Sciences
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• v.2 no.1
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• pp.24-28
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• 1996

The antiinflammatory and analgesic activities of higenamine were evaluated by measuring edema volume and pain threshold in adjuvant arthritic rats and acetic acid-induced writhing test in mice. Higenamine, with consecutive oral administrations at doses of 10 and 50 mg/kg/day, showed significant antiedemic effect and elevation of pain threshold during the secondary lesion of adjuvant arthritis. Higenamine also showed a significant inhibition of acetic acid-induced writhing syndrome with a single oral administration (200 mg/kg). From these results, it is postulated that higenamine might possess both of centrally and peripherally mediated analgesic properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.443-443
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• 2012

We fabricated a-IGZO TFT with AZO/Ag/AZO transparent multilayer source/drain contacts by rf magnetron sputtering. Enhanced electrical device performance of a-IGZO TFT with AZO/Ag/AZO multilayer S/D electrodes (W/L = = 400/50 mm) was achieved with a subs-threshold swing of 3.78 V/dec, a minimum off-current of 10-12 A, a threshold voltage of 1.80 V, a field effect mobility of 10.86 cm2/Vs, and an on/off ration of 9x109. It demonstrated the potential application of the AZO/Ag/AZO film as a promising S/D contact material for the fabrication of the high performance TFTs.

• 전기의세계
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• v.23 no.6
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• pp.49-55
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• 1974

Amorphous semiconductor from As 30 Te 48 Ge 10 Si 12 was prepared, and studied electron microscopy, X-ray analysis and resistivity measurement. It's resistivity is 1.56*10$^{6}$ .ohm.-cm when small ampule is used for preparing sample it is found that no phase separation has occurced by electron microscopy, and that phase transition temperature is 232.deg. C by differential Thermal Analysis. The specimen showed threshold switching that the low resistance state occur at critical electric field and the resistance recover at low applied field. Critical electric field of the switching is 10$^{5}$ V/cm at room temperature. Threshold voltage secreace exponentially with increasing ambient temperature and at that each voltage resistance of the switching device increase exponentially. According to the series resistance and applied vottage current slope on the V-I curve is varied. When applied voltage is decreased after switching, the resistance of the switching device is increased. By this result the origin of the switching is the Joule's heating.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.8
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• pp.580-583
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• 2012

The dependency of processing pressure on the electrical performances in amorphous silicon-zinc-tin-oxide thin film transistors (SZTO-TFT) has been investigated. The SZTO channel layers were deposited by using radio frequency (RF) magnetron sputtering method with different partial pressure. The field effect mobility (${\mu}_{FE}$) increased and threshold voltage ($V_{th}$) shifted to negative direction with increasing pressure during deposition processing. As a result, oxygen vacancies generated in SZTO channel layer with increasing partial pressure resulted in negative shift in $V_{th}$ and increase in on-current.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.514-516
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• 2018

We have investigated the effect of interface trap charge on the characteristics of a monolithic 3D inverter by TCAD simulation. The interface trap charge affects the variation of the threshold voltage and threshold voltage. also The interface trap charge affects the IN/OUT characteristics of the monolithic 3D inverter.

• Journal of Information Display
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• v.3 no.3
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• pp.35-43
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• 2002

Silicon-based 0.69-inch AMOEL microdisplay with integrated driver and timing controller circuits for microdisplay applications has been developed using 0.35 ${\mu}m$ l-poly 4-metal standard CMOS process with 5 V CMOS devices and CMP (Chemical Mechanical Polishing) technology. To reduce the large data programming time consumed in a conventional current programming pixel circuit technique and to achieve uniform display, de-amplifying current mirror pixel circuit and the current-mode data driver circuit with threshold roltage compensation are proposed. The proposed current-mode data driver circuit is inherently immune to the ground-bouncing effect. The Monte-Carlo simulation results show that the proposed current-mode data driver circuit has channel-to-channel non-uniformity of less than ${\pm}$0.6 LSB under ${\pm}$70 mV threshold voltage variaions for both NMOS and PMOS transistors, which gives very good display uniformity.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.150-155
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• 2004

The base material of optical disc is the amorphous polymer, polycarbonate. So crack growth on the rotating optical disc could happen by the static centrifugal force. This phenomenon is called static fatigue. Today's CD-R disc drive is being operated over 10,000 RPM. This is increasing the possibility of the disc fracture when operating. In this reason, new method to measure the static fatigue threshold quality and the way to calculate the threshold J-integral value and the safe crack length of the optical disc are studied. Finally the environmental effect to optical disc is also studied in this paper.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.6
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• pp.14-21
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• 1993

MODFETs using the heterostructure of phosphorous-contained a-SiN:H: and undoped a-Si:H films have been fabricated by PECVD of SiH$_{4}$, PH$_{3}$ gases. Thecharacteristics of the devices have been invetigated and compared with conventional TFTs(CTFTs). The threshold voltage of the MODFETs was smaller than that of CTFTs, in the case of the devices using the a-SiN:H film with the relatively high phosphorous content, the threshold voltage was negative and the operation of the devices followed the depletion mode. On the other hand, on/off current ratio of the MODFETs was more than one order of magnitude higher than the CTFTs, and the field effect mobility of the former was approximately two times as high as that of the latter.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.671-674
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• 2009

In this work, high-aspect-ratio graphite nanofibers (GNFs) were used to improve the electrical, thermal, and mechanical properties of the poly(methyl methacrylate) (PMMA) polymer, as well as those of PMMA composites suitable for use in bipolar plates. In the result, an electrical percolation threshold for the composites was formed between 1 and 2 wt% GNF content. This threshold was found to be influenced strongly by the three separate stages of the meltblending process. The composites exhibited higher thermal and mechanical properties and lower thermal shrinkage compared with the neat PMMA. Thus, GNFs were demonstrated to have positive impacts on the thermo-mechanical properties of PMMA composites and showed, thereby, reasonable potential for use in composites employed in the fabrication of bipolar plates.