• Journal of Broadcast Engineering
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• v.15 no.3
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• pp.414-425
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• 2010

When we implement the single frequency network (SFN) in ATSC terrestrial DTV system, there is an interference problem to DTV receivers due to the use of same frequency channel among transmitters and repeaters. To resolve this problem, it is recommended to adopt the transmitter identification signals in transmitting equipments. In this paper, we analyzed the influence suffered by legacy DTV receivers when the TxID signal is added to the DTV transmitting signals and the results were further verified by computer simulation, laboratory test and field test. The above tests show that if the TxID signal is added to the level of -30dB compared to the original DTV signal, the TOV(Threshold Of Visibility) increment in legacy receivers is about 0.17 dB. It means that we can insert and transmit the TxID signal in ATSC terrestrial DTV system without making the negative effect to the legacy DTV receivers.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.3
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• pp.678-684
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• 2009

It was reported that Dipsaci Radix has decrease pain effect on the Complex Region Pain Syndrome(CRPS). the CRPS was induced by unilateral loose occlusion in 4 part of the sciatic nerve of the rats. For the fingding significantly change on CRPS rats were divided into 4 different experimental groups. and each groups were induced CRPS. Experimental group I (control group; n=15), experimental group II (100 mg/kg Dipsaci Radix dieted rats; n=15), experimental group III (300 mg/kg Dipsaci Radix dieted rats; n=15), and experimental group IV(500 mg/kg Dipsaci Radix dieted rats; n=15). The study of Dipsaci Radix concentration was that foot withdrawal threshold to the thermal stimuli(Hot plate test), foot withdrawal threshold to the mechanical stimuli(von Frey's filament) and immunohistochemistry staining that were substance P. Hot plate test and von Frey Filament were increase in experimental group II, III, IV than group I, especially group III was most significantly change than group II and IV in post-hoc(Duncan's multiple range). and In immunohistochemistry observation; group I showed increase in the group II, III, IV. especially group III had the minimal level of the substance P expression while the experimental group II, III. These results suggested that the Dipsaci Radix dieted made the decrease of pain in CRPS.

• The Journal of Korean Physical Therapy
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• v.19 no.1
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• pp.11-22
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• 2007

Purpose: The purpose of this study were to analysis the effect on change of spinal neuron excitability during gait training of hemiplegia patients by the functional electrical stimulation. Methods: Thirty six hemiplegia patients participated in this study. Stimulation conditions of FES were pulse rate 35pps, pulse width $250{\mu}s$, and on-time 0.3 second, treatment hour was 30 min. and treatment period was once a day for five days a week through six weeks. For functional evaluations before and after treatment, Modified Ashworth Scale (MAS), active range of motion (AROM), Hmax threshold, H/Mmax ratio were measured and the following conclusions were obtained. Results: Functional evaluation showed significant changes in experimental group as MAS(p<0.01), AROM(p<0.001), compared to control group. In spinal neuron excitability evaluation, change of Hmax threshold was significantly reduced in both non weight bearing (p<0.001) and bearing condition (p<0.05), H/Mmax ratio was significantly reduced in non weight bearing (p<0.05) and bearing condition (p<0.05). Conclusion: In conclusion, application of FES to hemiplegia patients in recovery stage during gait training improved mitigation of muscular spasticity, balance adjustment and moving ability and it was interpreted that it was caused by mitigation of muscular spasticity by the spinal neuron excitability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.9
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• pp.2015-2020
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• 2012

The subthreshold characteristics has been analyzed to investigate the effect of two gate in Double Gate MOSFET using impact factor based on scaling theory. The charge distribution of Gaussian function validated in previous researches has been used to obtain potential distribution in Poisson equation. The potential distribution was used to investigate the short channel effects such as threshold voltage roll-off, subthreshold swings and drain induced barrier lowering by varying impact factor for scaling factor. The impact factor of 0.1~1.0 for channel length and 1.0~2.0 for channel thickness are used to fit structural feature of DGMOSFET. The simulation result showed that the subthreshold swings are mostly effected by impact factor but are nearly constant for scaling factors. And threshold voltage roll-off and drain induced barrier lowering are also effected by both impact factor and scaling factor.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.1-7
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• 2008

A study of new materials that are light-weight, high in strength has become vital to the machinery of auto industries. But then, there are a lot of problems with developing such materials that require expensive tools, and a great deal of time and effort. Therefore, the improvement of fatigue strength and fatigue life are mainly focused on by adopting residual stress. And Influence of corrosive condition for corrosion fatigue crack was investigated, after immersing in 3.5%NaCl, $10%HNO_3$+3.5%HF, $6%FeCl_3$. The immersion period was performed for 365days. The compressive residual stress was imposed on the surface according to each shot velocity based on shot peening, which is the method of improving fatigue life and strength. Fatigue life shows more improvement in the shot peened material than in the un peened material in corrosion conditions. The threshold stress intensity factor range was decreased in corrosion environments over ambient. Compressive residual stress of surface on the Shot-peen processed operate resistance force of fatigue crack propagation. The fatigue crack growth rate of the Shot-peened material was lower than that of the un peened material. Also m, fatigue crack growth exponent and number of cycle of the shot peened material was higher than that of the un peened material. That is concluded from effect of da/dN.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.71-74
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• 1996

Ta$_2$O$_{5}$ film ale recognized as promising capacitor dielectric for future DRAM\`s. The electrical properties of Ta$_2$O$_{5}$films greatly depend on the heating condition. In the practical fabrication process, several annealing process, such as the annealing of Al in H$_2$(about 40$0^{\circ}C$) and reflow of BPSG (borophosphosilicate glass) film in $N_2$(about 80$0^{\circ}C$), exist after deposition of Ta$_2$O$_{5}$ film. In this paper, we describe the temperature effect on the electrical properties of W/Ta$_2$O$_{5}$/Si structure. The thin film of Ta$_2$O$_{5}$ and tungsten have been deposited on p-si(100) wafer using the sputtering system. The heating temperature was varied from 500 to 90$0^{\circ}C$ in $N_2$for 30min and The degree of temperature is 100\`C. In a log(J/E$^2$) Vs 1/E plot of typical I-V data, we find a linear relationship for the temperature of 500, $600^{\circ}C$ and as deposition. This could indicate Fowler-Nordheim tunneling as the dominant mode of current transports. However, we can not find a linear relationship for the temperature above $700^{\circ}C$. This could not indicate Fowler-Nordheim tunneling as the dominant mode of current transport. The high frequency (1MHz) capacitance-voltage (C-V) of W/Ta$_2$O$_{5}$/Si Capacitor were investigated on the basis of shift in the threshold voltage and dielectric constant. The magnitude of the threshold voltage and dielectric constant depends on the heating temperature, and increases with heating temperature.temperature.

• Nuclear Engineering and Technology
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• v.32 no.1
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• pp.1-9
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• 2000

Delayed hydride cracking (DHC) velocity and threshold stress intensity factor for DHC ($K_{IH}$) tests in the radial direction on M11 pressure tube material in Wolsong unit 1 were carried out following the Atomic Energy Canada Limited (AECL) standard test procedure in order to identify the effect of undercooling on DHCV and to acquire the $K_{IH}$ data. The results showed that $K_{IH}$ 's were 8.8$\pm$0.8 MPa√m in the back offcut and 11.4$\pm$0.7 MPa√m in the front offcut. The fact that $K_{IH}$ in the front offcut is about 20% higher than that in the back offcut is attributed to the microstructural difference between the materials of the front and back ends. $K_{IH}$ 's in M11 pressure tube appeared to be higher than the values from the tubes made of double melted ingot reported earlier. This can be interpreted by the fact that very small amounts of Chlorine (Cl) and Phosphorus (P) are contained in the ingot and that the content of the harmful elements in the M11 pressure tube is equivalent to that made of a quadruple melting process. DHC velocities at 25$0^{\circ}C$ in the front offcut in the radial direction are measured to be 5~8$\times$10$^{-8}$ m/s. The results show that the prior thermal history change the DHC velocity significantly. This effect was confirmed by the experiment of undercooling prior to the DHC tests.DHC tests.

• Imaging Science in Dentistry
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• v.48 no.2
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• pp.111-119
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• 2018

Purpose: This study was conducted to evaluate the accuracy of linear measurements of 3-dimensional (3D) images generated by cone-beam computed tomography (CBCT) and facial scanning systems, and to assess the effect of scanning parameters, such as CBCT exposure settings, on image quality. Materials and Methods: CBCT and facial scanning images of an anthropomorphic phantom showing 13 soft-tissue anatomical landmarks were used in the study. The distances between the anatomical landmarks on the phantom were measured to obtain a reference for evaluating the accuracy of the 3D facial soft-tissue images. The distances between the 3D image landmarks were measured using a 3D distance measurement tool. The effect of scanning parameters on CBCT image quality was evaluated by visually comparing images acquired under different exposure conditions, but at a constant threshold. Results: Comparison of the repeated direct phantom and image-based measurements revealed good reproducibility. There were no significant differences between the direct phantom and image-based measurements of the CBCT surface volume-rendered images. Five of the 15 measurements of the 3D facial scans were found to be significantly different from their corresponding direct phantom measurements(P<.05). The quality of the CBCT surface volume-rendered images acquired at a constant threshold varied across different exposure conditions. Conclusion: These results proved that existing 3D imaging techniques were satisfactorily accurate for clinical applications, and that optimizing the variables that affected image quality, such as the exposure parameters, was critical for image acquisition.

• Polymer(Korea)
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• v.38 no.6
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• pp.767-773
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• 2014

Rheological and electrical properties of polystyrene (PS)/carbon nanotube (CNT) nanocomposites via coagulated precipitation were investigated. Chemical modification and surfactant wrapping of CNT to improve the dispersion of CNTs may reduce the intrinsic properties of pristine CNT. To avoid this problem, PS and CNTs were dissolved and dispersed in dimethylformamide and then PS/CNT nanocomposites were prepared by the coagulated precipitation of CNT-dispersed PS solution in water. The coagulated precipitation method was highly effective enhancing the electrical conductivity of nanocomposites. Furthermore, the effect of adding poly(styrene-co-divinylbenzene) crosslinked particles to PS matrix on the rheological and electrical properties was investigated. With the addition of the crosslinked particles, the electrical percolation threshold of CNT reduced to 0.25 wt% and electrical conductivity increased further. It is speculated that CNTs in the volume occupied by crosslinked particles helped electrical pathway formation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.881-883
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• 2005

In case is below length 100nm of gate, various kinds problem can be happened with by threshold voltage change of device, occurrence of leakage current by tunneling because thickness of oxide by 1.5nm low scaling is done and doping concentration is increased. SiO$_2$ dielectric substance can not be used for gate insulator because is expected that tunneling current become 1A/cm$^2$ in 1.5nm thickness low. In this paper, devised double gate MOSFET(DGMOSFET) to decrease effect of leakage current by this tunneling. Therefore, could decrease effect of these leakage current in thickness 1nm low of SiO$_2$ dielectric substance. But, very big gate insulator of permittivity should be developed for develop device of nano scale.