• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.4
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• pp.707-714
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• 2012

After a single-stage, second-order, multiple-feedback ${\Delta}-{\Sigma}$ modulator and a two-stage, second-order MASH ${\Delta}-{\Sigma}$ modulator were analyzed and simulated using Simulink and Matlab and their characteristics were compared, the following result was obtained: 1) The two ${\Delta}-{\Sigma}$ modulators do not have group delay distortion. 2) The characteristics of the noise shaping are nearly identical. As a result of the noise shaping, the power spectral densities have slope of 40 dB/dec. 3) There was no spurious tone. 4) The input range of the two modulators is from -1 to +1 in common. 5) Because the output of the two-stage MASH modulator is 2-bits (4-levels), design of frequency dividers and charge pumps of PLL are more demanding.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.571-576
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• 2016

Asymmetric double gate(DG) MOSFET has the different top and bottom gate oxides thicknesses. It is analyzed the deviation of subthreshold swing(SS) and conduction path for the ratio of top and bottom gate oxide thickness of asymmetric DGMOSFET. SS varied along with conduction path, and conduction path varied with top and bottom gate oxide thickness. The asymmetric DGMOSFET became valuable device to reduce the short channel effects like degradation of SS. SSs were obtained from analytical potential distribution by Poisson's equation, and it was analyzed how the ratio of top and bottom oxide thickness influenced on conduction path and SS. SSs and conduction path were greatly influenced by the ratio of top and bottom gate oxide thickness. Bottom gate voltage cause significant influence on SS, and SS are changed with a range of 200 mV/dec for $0<t_{ox2}/t_{ox1}<5$ under bottom voltage of 0.7 V.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.7
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• pp.96-101
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• 2013

In this paper we analyzed the effects of polystyrene(PS) blended in TIPS-pentacene on the performance of OTFTs. With the various molecular weight and the content of PS the performance of TIPS-pentacene OTFTs was examined and the proper molecular weight and the content were extracted for the best results. With the molecular weight of 9,580 and 0.3 wt% of PS OTFTs produced the mobility of $1.0{\pm}0.19cm^2/V{\cdot}sec$, the subthreshold slope $0.22{\pm}0.05$ V/dec, the threshold voltage $-1.19{\pm}1.21$ V, the current on/of ratio $7.12{\pm}2.09{\times}10^6$. Additionally the suitable substrate temperature for ink jet printing of the blended TIPS-pentacene OTFTs was also extracted and it was $46^{\circ}C$.

• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.98-103
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• 2001

The electrochemical characteristics and specific capacitance were investigated by preparation processes (dip coating method, doctor blade coating method and paste rolling method) of activated carbon electrode for an EDLC(electric double layer capacitor). The EDLC using $LiPF_6$ salts and PC-DEC solvents showed good specific capacitance, 130F/g and small IR-drop at linear time-voltage curve. 0.11V, Cyclic voltammetry analysis using the activated carbon electrode prepared by dip coating method was shown closer to ideal EDLC characterization.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.507-512
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• 2005

When carbon electrode is used as an anode in Li ion battery, passivation film forms on the electrode surface during the initial charge process due to so called Solid-Electrolyte Interphase (SEI). The passivation film formed by solvent decomposition during the initial charge process affects charge/discharge capacity. In this paper, 1 M $LiPF_6,EC:DEC$ (1 : 1, volume ratio) electrolyte with $Li_2CO_3$, at various temperatures, the electrochemical characteristics of passivation film formed on Kawasaki Mesophase Fine Carbon electrode surface were investigated by using chronopotentiometry, cyclic voltammetry, and impedance spectroscopy. Experimental observations indicated that as solvent decomposition occurred, the decomposition voltage was strongly dependent on ionic conductivity, which was low in the process at low temperature. The impedance of passivation film formed during the initial charge process, were dependent on the temperature.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.391-399
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• 2016

This study aimed to investigate the effect of verbal abuse experience, coping style and resilience on emotional response and practical stress. 261 nursing students participated in this study. The Data were collected using self-report questionnaires from Dec. 1 to Dec. 20, 2014. We found a positive correlation among verbal abuse experience, emotional coping style and stress during clinical practicum; a positive correlation among problem coping style, emotional coping style and resilience; a positive correlation among emotional coping style, emotional response and stress; a negative correlation among resilience and emotional response; a positive correlation among emotional response and stress during clinical practicum. The highest impact factors affecting the emotional response was emotional coping style(${\beta}=.422$). The highest impact factors affecting stress during clinical practicum was verbal abuse experience(${\beta}=.283$). Future efforts should be focused to provide interpersonal relation training and communication skills training for a safe environment of nursing students.

• Journal of IKEEE
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• v.23 no.2
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• pp.704-709
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• 2019

In this paper, the electrical characteristics of tunneling field effect transistor(TFET) was studied for different annealing conditions. The TFET samples annealed using hydrogen forming gas(4 %) and Deuterium($D_2$) forming gas(4 %). All the measurements were conducted in noise shielded environment. The results show that subthreshold slope(SS) decreased by 33 mV/dec after annealing process compared to before annealing. Under various temperature range, the noise is improved by average of 31.2 % for 10 atm Deuterium gas at $V_G=3V$ condition. It is also noticed that, post metal annealing with $D_2$ gas reduces the noise by average of 30.7 % at $I_D=100nA$ condition.

• Tunnel and Underground Space
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• v.29 no.1
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• pp.64-74
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• 2019

Behavior of a rock block consisting of rock joints during excavation of an underground opening is an important factor for the mechanical stability of the opening. In this study, the behavior of a rock block under different geostatic stress and joint property conditions was analyzed quantitatively. The behavior of the rock block analyzed by 3DEC numerical analysis was compared with that of the theoretical calculation, and the error between the theoretical value and the numerical analysis result was analyzed under various geostatic stress and joint property conditions. The result of the stability analysis of a rock block showed less than 5% of error with numerical simulation result, which verified the applicability of the purposed analytic solution.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.352-359
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• 1985

A clinical evaluation was performed on 811 cases of chest trauma who were admitted and treated at the department of thoracic & cardiovascular surgery, Catholic Medical College, during the past 19 years from Jan. 1966 to Dec. 1984. 1. The overall incidence rate of male to female was 3:1. 2. The common age groups were 4th, 5th, and 3rd decades. 3. The most common cause of chest trauma was stab in penetrating wound and traffic accidents in non penetrating wound. 4. The most common injury from non penetrating chest trauma was rib fracture [81.3%], and the incidence rate of flail chest was 14.5% of all cases of rib fractures. 5. The incidence rate of hemo-pneumothorax was 50.4% in non penetrating wounds, and 55.2% in penetrating wounds. 6. The most common method of surgical treatment was CTD [33.5%], and open thoracotomy was performed in 67 cases [8.3%]. 7, The overall mortality was 3.3% [27 cases], and common causes of the death were shock and respiratory insufficiency.

• Journal of Chest Surgery
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• v.17 no.3
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• pp.511-515
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• 1984

In this study, 213 cases of the spontaneous pneumothorax experienced at the department of thoracic and cardiovascular surgery, Chungnam National University Hospital during from April, 1977, till Dec, 1983 were reviewed. 1.Sex ratio of the studied patients was 7.19;1 showing high incidence male patients. The incidence according to the age group showed that 20.2%, 18.3% of the patients belong to the age group 6th, 5th decade respectively. 2.The etiologic factors were as follows, tuberculous origin in 50.2%, unknown origin in 28.2%, COPD in 3.3%, bullae in 8.5%. The site was right in 47.9% and left in 44.1%, bilateral in 8%. 3.The clinical symptoms were frequently dyspnea in 35%, chest pain in 27.5%. 4.The employed method of treatment were as follow, bed rest with oxygen inhalation in 1.9%, closed thoracostomy in 95.8%, open thoracotomy in 7.98%, which bullectomy was performed in 12 cases and pneumonectomy in 3 cases and lobectomy in 1 case and decortication with simple closure of bleb was performed in remaining 1 case. 5.The duration of closed thoracostomy was longer in tuberculosis, which average duration was 11.28 days. 6.The overall recurrent rate was 12.3%.