• Electrical & Electronic Materials
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• v.9 no.1
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• pp.30-37
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• 1996

Previously, crystallization of a-Si:H films on glass substrates were limited to anneal temperature below 600.deg. C, over 10 hours to avoid glass shrinkage. Our study indicates that the crystallization is strongly influenced by anneal temperature and weakly affected by anneal duration time. Because of the high temperature process and nonconducting substrate requirements for poly-Si TFTs, the employed substrates were limited to quartz, sapphire, and oxidized Si wafer. We report on poly-Si TFT's using high temperature anneal on a Si:H/Mo structures. The metal Mo substrate was stable enough to allow 1000.deg. C anneal. A novel TFT fabrication was achieved by using part of the Mo substrate as drain and source ohmic contact electrode. The as-grown a-Si:H TFT was compared to anneal treated poly-Si TFT'S. Defect induced trap states of TFT's were examined using the thermally stimulated current (TSC) method. In some case, the poly-Si grain boundaries were passivated by hydrogen. A-SI:H and poly-Si TFT characteristics were investigated using an inverted staggered type TFT. The poly -Si films were achieved by various anneal techniques; isothermal, RTA, and excimer laser anneal. The TFT on as grown a-Si:H exhibited a low field effect mobility, transconductance, and high gate threshold voltage. Some films were annealed at temperatures from 200 to >$1000^{\circ}C$ The TFT on poly-Si showed an improved $I_on$$I_off$ ratio of $10_6$, reduced gate threshold voltage, and increased field effect mobility by three orders. Inverter operation was examined to verify logic circuit application using the poly Si TFTs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.172-175
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• 2002

The technique of induced discharge by a pulsed CO2 laser is being applied to control electrical discharge path, material processing, triggered lightning for protecting the power equipments. In this paper, we have investigated about the characteristics of the induced discharge at atmospheric conditions by using a plasma channel, which is produced when a pulsed CO2 laser radiation is focused by a focusing mirror as a trigger source. A plasma channel produced by laser radiation has an effect on decreasing the threshold voltage and inducing the discharge in both needle electrodes. We have confirmed a delay time between a produced plasma channel and an electrical discharge after laser radiation. We provided the decreased voltage lower than the natural discharge voltage between electrode type of needles and was induced the discharge by forming a plasma channel between them. In this research we could understand the time delay of induced discharge by laser radiation, and the characteristics of the discharge cause by the decrease in the threshold voltage, and the polarity effect by changes of plasma channel positions between two electrodes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.10
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• pp.821-825
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO TFTs having different channel thicknesses deposited at low temperature. The ZnO films were deposited as active channel layer on $Si_3N_4/Ti/SiO_2/p-Si$ substrates by RF magnetron sputtering at $100^{\circ}C$ without additional annealing. Also, the ZnO thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film was deposited as gate insulator by PE-CVD at $150^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method. The fabricated devices have different threshold slop, field effect mobility and subthreshold slop according to channel thickness. This characteristics are related with ZnO crystal properties analyzed with XRD and SPM. Electrical characteristics of 60 nm ZnO TFT (W/L = $20\;{\mu}m/20\;{\mu}m$) exhibited a field-effect mobility of $0.26\;cm^2/Vs$, a threshold voltage of 8.3 V, a subthreshold slop of 2.2 V/decade, and a $I_{ON/OFF}$ ratio of $7.5\times10^2$.

• Journal of Preventive Medicine and Public Health
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• v.22 no.4 s.28
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• pp.474-479
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• 1989

This research was conducted to evaluate the effect of improvement in work environment and of segregation in a fluorescent lamp manufacturing factory. Among the total of 80 workers, 8 workers whose mercury concentration in urine reached a hazardous level ($200-299{\mu}g/l$) were moved to mercury free workplace. The follow-up examination for their mercury concentration in urine was done three times ; on May 3, 1988, September 1, 1988 and April 3, 1989. The results were as follows : 1. Mercury concentration in the air was reduced from 0.140 to 0.107 $mg/m^3$ in 4 months, and to $0.087mg/m^3$ in one year after environmental improvement in workplace. However the level still exceeded the Threshold Limit Value. 2. The geometric mean of urinary mercury concentration among 80 workers was $173.0{\mu}g/l\;(5.1{\sim}458.6{\mu}g/l$). The distribution of workers according to urinary mercury concentration showed that 9 workers (11.2%) were above the mercury poisoning level ($300{\mu}g/l$), 24 workers (30.0%) were $200-299{\mu}g/l$, 35 workers (43.8%) were $50-199{\mu}g/l$, and 12 workers (15.0%) were below 50 ${\mu}g/l$. 3. Among the 24 workers whose urinary mercury concentration was 200-299 $50-199{\mu}g/l$, 8 were able to be followed up. Their mean urinary mercury concentration before segregation was $244.9{\mu}g/l$, but decreased to $151.4{\mu}g/l$ in four months, $128.8{\mu}g/l$ in six months, and $46.8{\mu}g/l$ in one year after segregation.

• Journal of Korean Neurosurgical Society
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• v.60 no.5
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• pp.550-559
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• 2017

Objective : Subsidence is a frequent complication of anterior cervical discectomy and fusion. Postoperative segmental micromotion, thought to be a causative factor of subsidence, has been speculated to increase with uncinate process resection area (UPR). To evaluate the effect of UPR on micro-motion, we designed a method to measure UPR area based on pre- and postoperative computed tomography images and analyzed the relationship between UPR and subsidence as a proxy of micro-motion. Methods : We retrospectively collected clinical and radiological data from January 2011 to June 2016. A total of 38 patients (53 segments) were included. All procedures included bilateral UPR and anterior plate fixation. UPR area was evaluated with reformatted coronal computer tomography images. To reduce level-related bias, we converted UPR area to the proportion of UPR to the pre-operative UP area (pUPR). Results : Subsidence occurred in 18 segments (34%) and positively correlated with right-side pUPR, left-side pUPR, and the sum of bilateral pUPR (sum pUPR) (R=0.310, 301, 364; p=0.024, 0.029, 0.007, respectively). Multiple linear regression analysis revealed that subsidence could be estimated with the following formula : $subsidence=1.522+2.7{\times}sum\;pUPR$($R^2=0.133$, p=0.007). Receiver-operating characteristic analysis determined that sum $pUPR{\geq}0.38$ could serve as a threshold for significantly increased risk of subsidence (p=0.005, area under curve=0.737, sensitivity=94%, specificity=51%). This threshold was confirmed by logistic regression analysis for subsidence (p=0.009, odds ratio=8.471). Conclusion : The UPR measurement method confirmed that UPR was correlated with subsidence. Particularly when the sum of pUPR is ${\geq}38%$, the possibility of subsidence increased.

• Journal of Korean Physical Therapy Science
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• v.28 no.1
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• pp.46-53
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• 2021

Background: The purpose of this study was to investigate the effect of taping applied to the lower trapezius on the upper trapezius muscle tone, pain intensity, cervical rotation range of motion in chronic upper trapezius pain patients. Design: Case-control study. Methods: Twenty subjects with chronic upper trapezius pain were classified into an experimental group and a control group. The experimental group applied lower trapezius facilitation taping and the control group applied sham taping. Taping Before and after the application of taping, muscle tone, pain intensity, and cervical rotation range of motion of the upper trapezius were measured. Results: In the experimental group, there were significant differences in the pressure pain threshold and muscle tone before and after taping. In the comparison between groups, there was a significant difference in muscle tone between the experimental group and the control group. Conclusion: The application of the lower trapezius facilitation taping was found to be effective in reducing the pressure threshold and muscle tone of the upper trapezius. Therefore, it is expected that more effective treatment can be provided by adding lower trapezius facilitation taping to the treatment protocol for patients with chronic shoulder pain.

• Journal of Korean Physical Therapy Science
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• v.28 no.3
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• pp.30-41
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• 2021

Background: The purpose of this study was to investigate the effects of WBC on the pressure pain threshold, CK and LDH after exercise-induced muscle injury. Design: A Randomized Controlled Trial. Methods: In this study, these subjects were assigned into three groups, a control group (n=10), experiment group I (n=10) and experiment group II (n=10). The subjects in experimental group I were intervened by WBC (-130℃, 3 minutes) before induced EIMD, experimental group II were intervened by WBC (-130℃, 3 minutes) after induced EIMD and control group weren't by any intervened after induced EIMD. Results: First, In the comparison of the PPT, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the PPT of experimental group II was significantly larger than those of other groups (p<.01). Second, In the comparison of the CK, there were significant variations with the lapse the time in three groups (p<.001) and there was a significant interaction of time and group (p<.001). In the among group comparison, the CK of experimental group II was significantly smaller than those of other groups (p<.001). Third, In the comparison of the LDH, there were significant variations with the lapse the time in three groups (p<.01) and there was a significant interaction of time and group (p<.001). In the among group comparison, the LDH of experimental group II was significantly smaller than those of other groups (p<.001). Conclusion: The above results revealed that the WBC intervention after an exercise had a positive effect of muscle function after EIMD.

• Korean Journal of Exercise Nutrition
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• v.23 no.3
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• pp.22-28
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• 2019

[Purpose] The purpose of this study was to investigate the effect of diet plus exercise training and detraining for 12 weeks on body composition, aerobic performance, and stress-related variables in obese women. [Methods] Twenty-five women in their 20s-40s with 30% body fat and body mass indices above 25 kg/m² were divided into HR_LT (heart rate at lactate threshold) and HR_LT + 5% groups. Dietary intervention of 70% recommended dietary allowance (RDA) and exercise treatment composed of aerobic exercises on a bicycle (30 min) and treadmill (30 min) were then performed. These interventions were performed three times a week for 12 weeks. [Results] Dietary intake was significantly decreased, while daily activity significantly increased within the 12-week intervention period, and this effect was sustained after 12 weeks of detraining. Exercise training based on dietary intake and daily activity presented a significantly decreased weight and % body fat, improvement of aerobic performance, and a significant increase in heart rate variability (HRV) (e.g., average of all RR intervals and the square root mean squared differences of successive RR intervals) as stress-related variables. It was also confirmed that the improvement of body composition and stress-related variables were maintained even after detraining. [Conclusion] Our results suggest that 70% RDA of dietary intervention and exercise training corresponding to HR_LT and HR_LT + 5% for 12 weeks were effective in improving body composition and aerobic performance, and relieving stress. In particular, enhanced HRV persisted for up to 12 weeks after the end of exercise training in obese women.

• Journal of Adhesion and Interface
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• v.22 no.3
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• pp.91-97
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• 2021

By introducing an organic interlayer on the Parylene C dielectric surface, the electrical device performances and the operating stabilities of organic field-effect transistors (OFETs) were improved. To achieve this goal, hexamethyldisilazane (HMDS) and octadecyltrichlorosilane (ODTS), as the organic interlayer materials, were used to control the surface energy of the Parylene C dielectrics. For the bare case used with the pristine Parylene C dielectrics, the field-effect mobility (μ_FET) and threshold voltage (V_th) of dinaphtho[2,3-b:2',3'-f ]thieno[3,2-b]- thiophene (DNTT) FET devices were measured at 0.12 cm²V^-1s^-1 and - 5.23 V, respectively. On the other hand, the OFET devices with HMDS- and ODTS-modified cases showed the improved μ_FET values of 0.32 and 0.34 cm²V^-1s^-1, respectively. More important point is that the μ_FET and V_th of the DNTT FET device with the ODTS-modified Parylene C dielectric presented the smallest changes during a repeated measurement of 1000 times, implying that it has the most stable operating stability. The results could be meaned that the organic interlayer, especially ODTS, effectively covers the Parylene C dielectric surface with alkyl chains and reduces the charge trapping at the interface region between active layer and dielectric, thereby improving the electrical operating stability.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.4
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• pp.85-95
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• 2014

In the e-commerce, the conversion into the multi-media is the important issue. According to the research by Nielsen Korea, the 83% of customers who purchase the products in the e-commerce utilize multi-channel to buy the products such as mobile and online [3]. Thus, to effectively implement online advertising, marketers should understand the customers' path [15] in the multi-channel. The study of the multi-site activities plays an important role to predict customers' purchase [28]. To explain the e-commerce site visit activities of customers, we have developed research model in terms of the online advertising. This research model is based on the study of Moe and Fader [23]. There are two types of composition in the research model. First, general site visit as an exploratory search have net effect on the shopping site visit because customers could acquire or develop information on the e-commerce site via online advertising. Secondly, the e-commerce site visit as a goal-directed search cause threshold of the e-commerce site visit because customers could achieve their goal. When the threshold is increased, the probability of a shopping site visit is decreased and vice versa. Thus, we have investigated the impact of customers' previous visit activities (general site visit and shopping site visit) on the next e-commerce site visit in terms of dynamic view. Research data was provided by Cheil World Wide. This panel data include mobile and online log data of panelists from Jan. 2013 to March 2013. As the results, the customers' e-commerce site visit on the online media would decrease the probability of e-commerce site visit because these visit activities increase the threshold of e-commerce site visit. This result is similar with the previous study [23]. Otherwise, since e-commerce site visit on the mobile media decrease the threshold, the customers' probability of e-commerce site visit would increase In summary, the site visit activities on the mobile could improve the probability of e-commerce site visits.