• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.93-96
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• 1990

The characteristics of an inverted staggered-type hydrogenated amorphous silicon thin film transistor has been analyzed by employing numerical simulation. The field effect mobility and threshold voltage are characterized as a function of density of deep and tail states and lattice temperature. It has been found that the density of deep states plays an important role of determining the threshold voltage, while the field effect mobility are very sensitive to the slope of band tail states. Also, the numerically temperature dependence of field effect mobility and threshold voltage has been in good agreements with the experimental results.

• Transactions on Electrical and Electronic Materials
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• v.14 no.3
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• pp.156-159
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• 2013

The electrical properties of ZnO nanowire field effect transistors (FETs) have been investigated depending on various diameters of nanowires. The ZnO nanowires were synthesized with an Au catalyst on c-plane $Al_2O_3$ substrates using hot-walled pulsed laser deposition (HW-PLD). The nanowire FETs are fabricated by conventional photo-lithography. The diameter of ZnO nanowires is simply controlled by changing the thickness of the Au catalyst metal, which is confirmed by FE-SEM. It has been clearly observed that the ZnO nanowires showed different diameters simply depending on the thickness of the Au catalyst. As the diameter of ZnO nanowires increased, the threshold voltage of ZnO nanowires shifted to the negative direction systematically. The results are attributed to the difference of conductive layer in the nanowires with different diameters of nanowires, which is simply controlled by changing the catalyst thickness. The results show the possibility for the simple method of the fabrication of nanowire logic circuits using enhanced and depleted mode.

• The Journal of Korean Physical Therapy
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• v.12 no.3
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• pp.339-347
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• 2000

To elucidate pressure pain threshold of pericranial muscle due to involuntary. the effect of 30 min or forward head position(FHP) was studied in 20 patients with episodic tension-type headache and in 20 control without headache. Pressure pain thresholds were recorded before and after the FHP. and evaluated by pressure algometry. Thresholds increased in the patients and control after FHP. Relation between thresholds in patients anf control before FHP were not significant differences, but thresholds increased in patients after FHP. So, involutary muscle contraction due to FHP may be effect pressure pain threshold or pericranial muscle.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.116-121
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• 2013

Panaroma Sun roof's sun shade motor elicits two major sounds when operating: the tonal sound and the white noises. Generally, the sound related to the sharpness contributes the most to the quality of motors' tonal sound. The primary purpose of this study was to set the loudness of the motor's objective tonal sound utilizing the masking effect by its white noises. To conduct this study, the sound made by the operating sun shade motor was categorized into two different subsets of masker and test tone to examine the masking threshold. Also, the shifts of masking threshold were observed with the varying masker loudness.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.8
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• pp.34-45
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• 1994

We studied threshold voltages and I-V characteristics. considering short channel effect of the fully depleted thin film n-channel SOI MOSFET. We presented a charge sharing model when the back surface of short channel shows accumulation depletion and inversion state respectively. A degree of charge sharing can be compared according to each of back-surface conditions. Mobility is not assumed as constant and besides bulk mobility both the mobility defined by acoustic phonon scattering and the mobility by surface roughness scattering are taken into consideration. I-V characteristics is then implemented by the mobility including vertical and parallel electric field. kThe validity of the model is proved with the 2-dimensional device simulation (MEDICI) and experimental results. The threshold voltage and charge sharing region controlled by source or drain reduced with increasing back gate voltage. The mobility is dependent upon scattering effect and electric field. so it has a strong influence on I-V characteristics.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.1-15
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• 1990

The aim of this study was to investigate the effect of dental therapeutic agent on conduction velocity and threshold current of intradental A- and C-fibers in the cat. Inferior alveolar nerve of cat anesthetized with sodium pentobarbital was exposed and dissected until response of functional single pulp nerve until could be evoked by monopolar electrical stimulation of the crown of the lower left canine teeth. 10ms rectangular pulse was used to determine the threshold current and 1ms rectangular pulse was used to determine conduction velocity. After application of calcium chloride (1, 2, 6M), calcium hydroxide mixed with saline, potassium chloride (0.2, 0.8, 1.6M), eugenol, zinc oxide eugenol to the cavity on the labial surface, conduction velocity and threshold current of single pulp nerve unit were compared with the control. In 10 cats, 24 $A{\delta}$- and 11 C- pulp nerve units were recorded. The mean conduction velocities of $A{\delta}$- and C-fibers were 7.5m/sec (SD=5.8) and 1.2m/sec (SD=0.4), respectively. The mean threshold current was $12.3{\mu}A$ (SD=5.3) for $A{\delta}$-fibers and $24.9{\mu}A$ (SD=8.1) for C-fibers. 1, 2, 6M calcium chloride caused decrease of conduction velocity and remarkable increase of threshold current in $A{\delta}$- and C-fibers. The effect of calcium hydroxide mixed with saline was similar but smaller than calcium chloride solution. 0.2M potassium chloride had insignificant effect. In 0.8M potassium chloride, the threshold current was increased although conduction velocity was not affected. In 1.6M potassium chloride, the threshold current was increased and the conduction velocity was slowed down. Spontaneous activity was recorded frequently for first 5 min but gradually reduced both in $A{\delta}$- and C-fibers. Eugenol had irreversible effect on pulp nerve in that initially there were not certain changes in the conduction velocity and threshold current of $A{\delta}$- and C-fibers, but the responses to electrical stimulation were abruptly disappeared after sustained application and were not recovered. Contrary to eugenol, zinc oxide eugenol did not caused significant increase of the threhold current and caused time dependent decrease of the conduction velocity, and did not show any irreversible change.

• Journal of Applied Reliability
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• v.17 no.3
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• pp.246-255
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• 2017

Purpose: This study proposes the optimal PM (preventive maintenance) policy of leased equipment for lessee's decision-making using two types of reliability condition. Methods: We consider reliability threshold based PM model. Equipment reliability is estimated and used as condition variable. The effect of repair for maintenance is imperfect and represented by age reduction factor. Results: We provide two PM policies. Policy 1 is focused on minimized total cost. This policy guarantees reliability threshold until last maintenance action. Policy 2 focus on maintaining reliability threshold during leased period. The proposed approach provides optimal reliability threshold under number of PM. Through result, we finally construct decision-making process for lessee using reliability threshold and end of reliability. Conclusion: This study provides two PM policy for lessee's decision-making. Through numerical example, we get a result of optimal reliability threshold, number of PM, optimum alternative under lessee's reliability condition.

• The Journal of Korean Physical Therapy
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• v.6 no.1
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• pp.85-93
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• 1994

The purposes of this study were 1) to examine the effects of microcurrent electrical neuromuscular stimulation 2) to compare surface electrode with needle electrode at somatic acupuncture points on experimental pain threshold measured at the distal end of the radius 3) to determine the changes in effect over time. A total of sixty healthy adult male and female subjects were assigned randomly to one of two experimental group or to a control group. Group 1(n=20) received MENS(Microcurrent Electrical Neuromuscular Stimulation) with surface electrode. Group 2(n=20) received HENS with needle electrode. Group 3(n=20) received no MENS. It measured experimental pain threshold at the wrist on pretreatment, 0 min after treatment. 15 min after treatment, 30 min after treatment in two experimental group. The results were as follows: 1. Experimental pain thresholds were higher in males than females(P<0.01). 2. Only the experimental group exhibited a significant increased in pain threshold after MENS treatment(P<0.05). 3. Surface electrode group increased significant pain threshold 0 min, 15 min after treatment, but greatly decrease 30 min after treatment. 4. Needle electrode group increased significant pain threshold 0 min, 15 min after treatment, but decrease 30 min after treatment. The results suggest that MENS applied to appropriate somatic acupuncture point can increase pain threshold. Further research is needed to assess the effects of greatly variety intensity of MENS of pain sufferes.

• The Journal of Korean Physical Therapy
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• v.26 no.6
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• pp.442-448
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• 2014

Purpose: The objective of this study is to evaluate the effect of neuro-feedback training and transcutaneous electrical nerve stimulation (TENS) on stress, quantitative sensory threshold and pain in patients suffering from tension type headache. Methods: 22 participants who passed the preliminary evaluation were enrolled in the study and 11 participants were randomly assigned to each group. The control group (n=11) was subject to the TENS treatment of which was composed of a 20-minute session for 5 times a week during 4 weeks, and the experimental group (n=11) was subject to both neuro feedback training and TENS treatment for 10 minutes a day and 5 days a week during 4 weeks. The Perceived Stress Scale (PSS) was used to measure a level of stress and the quantitative sensory testing (QST) was used for the measurement of cold pain threshold (CPT) and heat pain threshold (HPT); A degree of pain was evaluated through the headache impact test-6 (HIT-6). Results: In comparision of all dependent variables between the control and subject groups, there were significant differences in stress, quantitative sensory threshold and pain after the treatment (p<0.05), and the experimental group showed significant differences in stress, CPT, HPT and pain (p<0.05) and the control group showed only a significant difference in HPT (p<0.05). Conclusion: Findings of this study demonstrate that the concomitant administration of the TENS treatment and neuro feedback training is effective on alleviation of stress, quantitative sensory threshold and pain in patients with tension type headache.

• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.10-14
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• 2013

In this paper, when applying current-mode circuit design technique showing constant power dissipation none the less operation frequency, to the low power design of dynamic voltage frequency scaling, we introduce the low power current-mode circuit design technique applying MOSFET in sub-threshold region, in order to solve the problem that has large power dissipation especially on the condition of low operating frequency. BSIM 3, was used as a MOSFET model in circuit simulation. From the simulation result, the power dissipation of the current memory circuit with sub-threshold MOSFET showed $18.98{\mu}W$, which means the consumption reduction effect of 98%, compared with $900{\mu}W$ in that with strong inversion. It is confirmed that the proposed circuit design technique will be available in DVFS using a current-mode circuit design.