• Korean Journal of School Psychology
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• v.16 no.2
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• pp.207-230
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• 2019

This study examined the effect of Attention Feedback Awareness and Control Training(A-FACT) on attention bias and generalized anxiety symptoms in college students. A total of 31 college students with at least 10 points on the Generalized Anxiety Disorder 7-item (GAD-7) scale or at least 56 points on the Korean version of the Penn State Worry Questionnaire (K-PSWQ) with attention bias were randomly assigned to one of three groups: A-FACT( n = 11), Attention Bias Modification (ABM)(n = 10) and Active Placebo Control (APC)(n = 10). Participants in A-FACT group received real-time feedback on attention bias based on their Baseline Neutral Response time(BNR) during A-FACT using a dot probe task. Participants in the ABM group received standard ABM, and those in the APC performed a dot probe task that they were informed was a program to reduce attention bias, but feedback was not provided. A total of eight sessions was conducted twice a week over a 4-week period. After every two sessions, GAD-7, K-PSWQ and K-STAI were rated. The effect of attention bias modification training was rated by changes in the Attention Bias Score(ABS), and in GAD-7, K-PSWQ and K-STAI scores. The results of repeated measure ANOVA indicated that the A-FACT group showed a significant decrease in ABS as well as in GAD-7, K-PSWQ and K-STAI scores compared to the other groups. Current results suggest that self-regulatory control of attention, that is, recognition of bias through feedback in A-FACT, may be effective in alleviating attention bias and generalized anxiety symptoms by recognizing bias through feedback on bias in attention bias modification training.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.1-6
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• 2009

The experimental results of exposing IGBT (Insulated Gate Bipolar Transistor) samples to gamma radiation source show shifting of threshold voltages in the MOSFET and degradation of carrier mobility and current gains. At low total dose rate, the shift of threshold voltage is the major contribution of current increases, but for more than some total dose, the current is increased because of the current gain degradation occurred in the vertical PNP at the output of the IGBTs. In the paper, the collector current characteristics as a function of gate emitter voltage (VGE) curves are tested and analyzed with the model considering the radiation damage on the devices for gate bias and different dose. In addition, the model parameters between simulations and experiments are found and studied.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.3
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• pp.87-97
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• 2021

Purpose : The purpose of this meta-analysis was to evaluate the effects of transcranial direct current stimulation on the lower extremity function of stroke patients. Methods : Domestic data were gathered from studies that conducted clinical trials associated with transcranial direct current stimulation and its impact on lower extremity function of stroke patients. A total of 592 studies published between 2012 and 2020 were identified, with 7 studies satisfying the inclusion data. The studies consisted of patient, intervention, comparison, and outcome (PICO) data. The search outcomes were items associated with muscle activity, balance, muscle strength and walking ability. Cochrane risk of bias (ROB) was used to evaluate the quality of 3 randomized control trials. The quality of 4 non-randomized control trials was evaluated using risk of bias assessment tool for non-randomized studies (RoBANS). Effect sizes in this study were computed as the corrected standard mean difference (SMD). A random-effect model was used to analyze the effect size because of the high heterogeneity among the studies. Egger's regression and 'trim-and-fill' tests were carried out to analyze the publishing bias. Results : The following factors had a large total effect size (Hedges's g=2.10, 95 %CI=1.54~2.66) involving transcranial direct current stimulation on stroke patients: muscle activity (Hedges's g=2.38, 95 %CI=1.08~3.68), balance (Hedges's g4=2.41, 95 %CI=1.33~3.60), walking ability (Hedges's g=1.54, 95 %CI=0.49~2.59), and muscle strength (Hedges's g=2.45, 95 % CI: 0.85~4.05). Egger's regression test showed that the publishing bias had statistically significant differences but 'trim-and-fill' test showed that there was still statistical difference. Conclusion : This study provides evidence for the effectiveness of transcranial direct current stimulation on the lower extremity in terms of muscle activity, balance, walking ability, and muscle strength in stroke patients. However, due to the low quality of studies and high heterogeneity factors, the results of our study should be interpreted cautiously.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.1
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• pp.92-99
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• 1994

Diamond thin film was deposited on n type (100) Si substrate by MPECVD(Microwave plasma Enhanced Chemical Vapor Deposition). For the increase in nucleation density of diamond, Si substrate was pretreated by diamond powder or negative bias voltage was applied to the substrate during the initial deposition. In the case of retreated Si substrate, the diamond thin film quality was enhanced with increasing the total pressure in the range of 20~150 Torr. For the negative bias voltage, the formation condition of the diamond was seriously affected by $CH_4$ concentration and total pressure. The formation condition will be discussed with electrical current of substrate generated by plasma ions which depend on $CH_4$concentration, bias voltage, and total pressure.

• Progress in Superconductivity
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• v.4 no.1
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• pp.42-47
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• 2002

Measuring magnetic fields with a SQUID sensor always requires preliminary adjustments such as optimum bas current determination and flux-locking point search. A conventional magnetoencephalography (MEG) system consists of several dozens of sensors and we should condition each sensor one by one for an experiment. This timeconsuming job is not only cumbersome but also impractical for the common use in hospital. We had developed a serial port communication protocol between SQUID sensor controllers and a personal computer in order to control the sensors. However, theserial-bus-based control is too slow for adjusting all the sensors with a sufficient accuracy in a reasonable time. In this work, we introduce programmatic control sequence that saves the number of the control pulse arrays. The sequence separates into two stages. The first stage is a function for searching flux-locking points of the sensors and the other stage is for determining the optimum bias current that operates a sensor in a minimum noise level Generally, the optimum bias current for a SQUID sensor depends on the manufactured structure, so that it will not easily change about. Therefore, we can reduce the time for the optimum bias current determination by using the saved values that have been measured once by the second stage sequence. Applying the first stage sequence to a practical use, it has taken about 2-3 minutes to perform the flux-locking for our 37-channel SQUID magnetometer system.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.390.1-390.1
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• 2016

The present work explains the interfacial energetics of all oxide transparent photodiodes. The optical, structural and morphological of copper oxides were systematically analyse by UV-Visible spectrometer, X-Ray diffraction, Raman spectroscopy, Scanning electron microscopy (SEM) and Atomic force microscopy measurements (AFM). The UV-Visible result exhibits optical bandgap of Cu2O and CuO as 2.2 and 2.05 eV respectively. SEM and AFM result shows a uniform grain size distribution in Cu2O and CuO thin films with the average grain size of 45 and 40 nm respectively. The results of Current-Voltage and Kelvin probe force microscope characteristics describe the electrical responses of the Cu2O/ZnO and CuO/ZnO heterojunctions photodiodes. The obtained electrical response depicts the approximately same knee voltages with a measurable difference in the absolute value of net terminal current. More over the present study realizes the all oxide transparent photodiode with zero bias photocurrent. The presented results lay the template for fabricating and analysing the self-bias all oxide transparent photodetector.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.163-163
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• 2015

The effect of nematic liquid crystal(5CB-4-Cyano-4'-pentylbiphenyl) on the amorphous indium gallium zinc oxide thin film transistors(a-IGZO TFTs) was investigated. Through dropping the 5CB on the a-IGZO TFT's channel layer which is deposited by RF-magnetron sputtering, properties of a-IGZO TFTs was dramatically improved. When drain bias was induced, 5CB molecules were oriented by Freedericksz transition generating positive charges to one side of dipoles. From increment of the capacitance by orientation of liquid crystals, the drain current was increased, and we analyzed these phenomena mathematically by using MOSFET model. Transfer characteristic showed improvement such as decreasing of subthreshold slope(SS) value 0.4 to 0.2 and 0.45 to 0.25 at linear region and saturation region, respectively. Furthermore, in positive bias system(PBS), prevention effect for electron trapping by 5CB liquid crystal dipoles was observed, which showing decrease of threshold voltage shift [(${\delta}V$]_TH) when induced +20V for 1~1000sec at the gate electrode.

• The Journal of Information Systems
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• v.24 no.3
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• pp.75-94
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• 2015

Purpose While new versions of mobile applications could offer users better computing environment, users are not always comfortable with them for various reasons. Considering making update decisions is important task for users, it is crucial for us to understand users' behavior and attitude on app updates. The purpose of this study is to explain why mobile users succumb to both reactance toward the update and satisfaction to the current version, ultimately leading them to feel the regret by employing three theoretical perspectives including regret theory, status quo bias theory and the dual model. Design/methodology/approach Survey data collected from 204 mobile users was used to test the research model using partial least squares analysis. The results have shown that both reactance toward the update and satisfaction to the current version have negative impacts on individuals' decisions to update, which leading to their regret after updating the applications Findings By integrating both status quo bias and regret theory in the model, this study tried to explain why mobile users feel regret in application update settings. More specifically, this study has proposed a novel framework that introduces an individual's update decision on mobile applications.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.128.2-128.2
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• 2014

Long-wave infrared detectors using the type-II InAs/GaSb strained superlattice (T2SL) material system with the nBn structure were designed and fabricated. The band gap energy of the T2SL material was calculated as a function of the thickness of the InAs and GaSb layers by the Kronig-Penney model. Growth of the barrier material (Al0.2Ga0.8Sb) incorporated Te doping to reduce the dark current. The full width at half maximum (FWHM) of the 1st satellite superlattice peak from the X-ray diffraction was around 45 arc sec. The cutoff wavelength of the fabricated device was ${\sim}10.2{\mu}m$ (0.12eV) at 80 K while under an applied bias of -1.4V. The measured activation energy of the device was ~0.128 eV. The dark current density was shown to be $1.2{\times}10^{-5}A/cm^2$ at 80 K and with a bias -1.4 V. The responsivity was 1.9 A/W at $7.5{\mu}m$ at 80K and with a bias of -1.9V.

• Transactions on Electrical and Electronic Materials
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• v.16 no.3
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• pp.151-155
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• 2015

We fabricated the Cu Schottky contact on an n-type Ge wafer and investigated the forward bias current-voltage (I-V) characteristics in the temperature range of 100~300 K. The zero bias barrier height and ideality factor were determined based on the thermionic emission (TE) model. The barrier height increased and the ideality factor decreased with increasing temperature. Such temperature dependence of the barrier height and the ideality factor was associated with spatially inhomogeneous Schottky barriers. A notable deviation from the theoretical Richardson constant (140.0 Acm^-2K^-2 for n-Ge) on the conventional Richardson plot was alleviated by using the modified Richardson plot, which yielded the Richardson constant of 392.5 Acm^-2K^-2. Finally, we applied the theory of space-charge-limitedcurrent (SCLC) transport to the high forward bias region to find the density of localized defect states (N_t), which was determined to be 1.46 × 10¹² eV^-1cm^-3.