• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.7
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• pp.521-524
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• 2012

We report on variations of electrical properties with different active layer thickness and post-annealing temperature in amorphous In-Ga-Zn-O (IGZO) thin-film transistors (TFTs). In particular, subthreshold swing (SS) of the IGZO-TFTs was improved as increasing the active layer thickness at an given post-annealing temperature, accompanying the negative shift in turn-off voltage. However, as increasing post-annealing temperature, only turn-off voltage was shifted negatively with almost constant SS value. The effect of the active layer thickness and post-annealing temperature on electrical properties, such as SS, field effect mobility and turn-off voltage in IGZO-TFTs has been explained in terms of the variation of trap density in IGZO channel layer and at gate dielectric/IGZO interface.

• Atmosphere
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• v.22 no.2
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• pp.187-197
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• 2012

This study investigates the relationship between the Korean temperature and the atmospheric circulation such as Arctic Oscillation, Siberian High and Aleutian Low during the winter (December-January) for the period of 1970-2011. It is found that all indices to represent aforementioned circulations are significantly correlated with Korean winter temperature for the period of 1970 - 2011. There are marked contrasts in such relationship, however, before and after the mid-1980s when a significant regime shift of Korean winter temperature occurred. While Korean winter temperature has a close relationship with Arctic Oscillation after the mid-1980s, its relationship with Siberian High and Aleutian Low is weakened. The composite analysis between a positive and negative phase of Arctic Oscillation before and after the mid-1980s is conducted to examine a recent strengthening of Arctic Oscillation-Korean winter temperature relationship. It is found that the structural changes of low-level wind and the geopotential height at 500 hPa between the two phases of Arctic Oscillation are more effective to influence Korean winter temperature after the mid-1980s. This may induce a close relationship between the Korean winter temperature variability and Arctic Oscillation after the mid-1980s compared to before the mid-1980s.

• Asia pacific journal of information systems
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• v.25 no.2
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• pp.306-328
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• 2015

A recent trend in innovation paradigm is the shift from closed innovation to open innovation principles. This trend is characterized by the use of purposive inflows and outflows of knowledge not only to accelerate internal innovation, but also to expand the markets for external use of innovation. However, the Not-Invented-Here (NIH), and Not-Sold-Here (NSH) or Only-Use-Here (OUH) syndromes are the most common challenges encountered in open innovation processes. Therefore, this study has the following main aims: 1) propose a research model that explains the factors that influence NIH and NSH/OUH attitudes based on motivation theory with perceived organizational fairness and commitment, 2) investigate their impacts on NIH and NSH/OUH attitudes, and 3) provide useful theoretical and practical insights. The proposed research model was empirically tested using survey data collected from information technology (IT) professionals in Korea. One of the major findings indicates that IT professionals' perceived organizational fairness has a negative effect on NIH attitudes in open innovation process. Theoretical and practical contributions of this study are also discussed.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.sup1
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• pp.130-133
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• 2008

Adrenal tumors are increasingly detected by widespread use of anatomical imaging such as a, MRI, etc. For these adrenal tumors, differentiation between malignancy and benignancy is very important. In diagnostic assessment of adrenal tumor, $^{18}F-FDG$ PET and PET-CT have been reported to have high diagnostic performance, especially, very excellent performance in evaluation of adrenal metastasis in the oncologic patient. In cases of adrenal incidentalomas, $^{18}F-FDG$ PET or PET-CT is helpful if a or chemical-shift MRI is inconclusive. $^{18}F-FDG$ PET and PET-CT may be applied to the patients with MIBG-negative pheochromocytomas. In summary, $^{18}F-FDG$ PET and PET-CT are expected to be effective diagnostic tools in the management of adrenal tumor.

• JSTS:Journal of Semiconductor Technology and Science
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• v.1 no.3
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• pp.158-166
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• 2001

Based on uniform hot carrier injection (optically assisted electron injection) across the $Si-SiO_2$ interface into the gate insulator of n-channel IGFETs, the threshold voltage shifts associated with electron injection of $1.25{\times}l0^{16}{\;}e/\textrm{cm}^2 between 0.5 and 7 MV/cm were found to decrease from positive to negative values, indicating both a decrease in trap cross section ($E_{ox}{\geq}1.5 MV/cm$) and the generation of FPC $E_{ox}{\geq}5{\;}MV/cm$). It was also found that FNC and large cross section NETs were generated for $E_{ox}{\geq}5{\;}MV/cm$. Continuous, uniform low-field (1MV/cm) electron injection up to $l0^{19}{\;}e/\textrm{cm}^2 is accompanied by a monatomic increase in threshold voltage. It was found that the data could be modeled more effectively by assuming that most of the threshold voltage shift could be ascribed to generated bulk defects which are generated and filled, or more likely, generated in a charged state. The injection method and conditions used in terms of injection fluence, injection density, and temperature, can have a dramatic impact on what is measured, and may have important implications on accelerated lifetime measurements.

• Journal of Welding and Joining
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• v.21 no.3
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• pp.85-91
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• 2003

Narrow gap welding has many advantages over conventional V-grooved butt welding such as high productivity, small deformation and improved mechanical property of joints. With narrower groove gap, less arc heat input is expected will all the other advantages of narrow gap welding. The main defects of narrow gap welding include the lack of root fusion, convex bead surface and irregular surface, all of which have negative effects on the next welding pass. This paper suggests an up-and-down torch oscillation for ultra narrow gap welding with gap size of 5mm and investigates the proper welding conditions to fulfill the reliable and high welding quality. First, GMA welding model was suggested for ultra narrow gap welding system with Halmoy's model referenced for wire melting modeling. And the arc length in ultra narrow gap was defined. Secondly, based on the experimental results of up-and-down torch oscillation welding, phase shift of current and wire extension length were simulated for varying oscillation frequency to show that weld the bead shape in ultra narrow gap welding can be predicted. As the result, it was confirmed that reliable weld quality in ultra narrow gap welding can be achieved with up-and-down torch oscillation above 15Hz due to its ability to provide uniform heat input along the sidewall of gap.

• JSTS:Journal of Semiconductor Technology and Science
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• v.3 no.2
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• pp.83-88
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• 2003

The reset operation of a CCD image sensor was improved using charge trapping of a MOS structure to realize a loe voltage driving. A DC bias generating circuit was added to the reset structure which sets reference voltage and holds the signal charge to be detected. The generated DC bias is added to the reset pulse to give an optimized voltage margin to the reset operation, and is controlled by adjustment of the threshold voltage of a MOS transistor in the circuit. By the pulse-type stress voltage applied to the gate, the electrons and holes were injected to the gate dielectrics, and the threshold voltage could be adjusted ranging from 0.2V to 5.5V, which is suitable for controlling the incomplete reset operation due to the process variation. The charges trapped in the silicon nitride lead to the positive and negative shift of the threshold voltage, and this phenomenon is explained by Poole-Frenkel conduction and Fowler-Nordheim conduction. A CCD image sensor with $492(H){\;}{\times}{\;}510(V)$ pixels adopting this structure showed complete reset operation with the driving voltage of 3.0V. The resolution chart taken with the image sensor shows no image flow to the illumination of 30 lux, even in the driving voltage of 3.0V.

• Ocean and Polar Research
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• v.34 no.3
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• pp.275-286
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• 2012

Over the last 20 years there have been more than 3000 peer-reviewed papers relating to climate change and biodiversity published, and still the numbers are increasing. However, most studies focused on the impacts of climate change at population or community levels, and the results invariably reveal that there has been, or will be, a negative effect on the structure and pattern of biodiversity. Moreover, the climate change models and statistical analyses used to test the impacts are only newly developed, and the analyses or predictions can often be misled. In this review, I ask why an individual's life history is considered in the study how climate change affects biodiversity, and what ecological factors are impacted by climate change. Using evidence from a range of species, I demonstrate that diverse life history traits, such as early growth rate, migration/foraging behaviour and lifespan, can be shifted by climate change at individual level. Particularly I discuss that the optimal decision under unknown circumstance (climate change) would be the reduction of the ecological fitness at individual level, and hence, a shift in the balance of the ecosystem could be affected without having a critical impact on any one species. To conclude, I summarize the links between climate changes, ecological decision in life history, the revised consequence at individual level, and discuss how the finely-balanced relationship affects biodiversity and population structure.

• The Journal of Asian Finance, Economics and Business
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• v.4 no.1
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• pp.19-23
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• 2017

Based on a simultaneous-equation model consisting of aggregate demand and short-run aggregate supply, this paper estimates a reduced-form equation specifying that the equilibrium real GDP is a function of the real effective exchange rate, the government deficit as a percent of GDP, the real interest rate, foreign income, labor productivity, the real oil price, the expected inflation rate, and the interactive and intercept binary variables accounting for a potential change in the slope of the real effective exchange rate and shift in the intercept. Applying the exponential GARCH technique, it finds that aggregate output in Australia has a positive relationship with the real effective exchange rate during 2003.Q3 - 2013.Q2, the government deficit as a percent of GDP, U.S. real GDP, labor productivity and the real oil price and a negative relationship with the real effective exchange rate during 2013.Q3 - 2016.Q1, the real lending rate and the expected inflation rate. These results suggest that real appreciation was expansionary before 2013.Q3 whereas real depreciation was expansionary after 2013.Q2 and that more government deficit as a percent of GDP would be helpful to stimulate the economy. Hence, the impact of real appreciation or real depreciation on real GDP may change overtime.

• Applied Science and Convergence Technology
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• v.23 no.4
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• pp.192-199
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• 2014

The electronic property of graphene was investigated by hydrazine treatment. Hydrazine ($N_2H_4$) highly increases electron concentrations and up-shifts Fermi level of graphene based on significant shift of Dirac point to the negative gate voltage. We have observed contact resistance and channel length dependent mobility of graphene in the back-gated device after hydrazine monohydrate treatment and continuously monitored electrical characteristics under Nitrogen or air exposure. The contact resistance increases with hydrazine-treated and subsequent Nitrogen-exposed devices and reduces down in successive Air-exposed device to the similar level of pristine one. The channel conductance curve as a function of gate voltage in hole conduction regime keeps analogous value and shape even after Nitrogen/Air exposure specially whereas, in electron conduction regime change rate of conductance along with the level of conductance with gate voltage are decreased. Hydrazine could be utilized as the highly effective donor without degradation of mobility but the stability issue to be solved for future application.