• JSTS:Journal of Semiconductor Technology and Science
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• 제14권1호
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• pp.34-39
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• 2014

This paper discusses the 3-level charge pumping (CP) method in planar-type Silicon-Oxide-High-k-Oxide-Silicon (SOHOS) and Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) devices to find out the reason of the degradation of data retention properties. In the CP technique, pulses are applied to the gate of the MOSFET which alternately fill the traps with electrons and holes, thereby causing a recombination current Icp to flow in the substrate. The 3-level charge pumping method may be used to determine not only interface trap densities but also capture cross sections as a function of trap energy. By applying this method, SOHOS device found to have a higher interface trap density than SONOS device. Therefore, degradation of data retention characteristics is attributed to the many interface trap sites.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.41-44
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• 2021

We developed an optimization process of the pulsed laser deposition method to grow epitaxial CeCoIn₅ thin films on MgF₂ substrates. The effects of different deposition parameters on film growth were extensively studied by analyzing the measured X-ray diffraction patterns. All the deposited films contained small amounts of CeIn₃ impurity phase and misoriented CeCoIn₅, for which the c-axis of the unit cell is perpendicular to the normal vector of the substrate surface. The deposition temperature, target composition, laser energy density, and repetition rate were found effective in the formation of (00l)-oriented CeCoIn₅ as well as the undesired phases such as CeIn₃, misoriented CeCoIn₅ along the (112) and (h00). Our results provide a set of deposition parameters that produce high-quality epitaxial CeCoIn₅ thin films with sufficiently low amounts of impurity phases and can serve as a reference for future studies to optimize the deposition process further.

• Journal of Electrochemical Science and Technology
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• 제14권3호
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• pp.272-282
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• 2023

Ni-rich layered oxides cathode has recently gained attention as an advanced cathode material due to their applicable energy density. However, as the Ni component in the layered site is increased, the high reactivity of Ni⁴⁺ results in parasitic reaction associated with decomposing electrolyte, which leads to a rapid decreasing the lifespan of the cell. The electrolyte additive triallyl borate (TAB) improves interfacial stability, leading to a stable cathode-electrolyte interphase (CEI) layer on the LNCM83 cathode. A multi-functionalized TAB additive can produce a uniformly distributed CEI layer via electrochemical oxidation, which implies an increase in long-term cycling performance. After 100 cycles at elevated temperature, the cell tested by 0.75 TAB retained 88.3% of its retention ratio, whereas the cell performed by TAB-free electrolyte retained 64.1% of its retention. Once the TAB additive formed CEI layers on the LNCM83 cathode, it inhibited the decomposition of carbonate-based solvents species in addition to the dissolution of transition metal components from the cathode. The addition of TAB to LNCM83 cathode material is believed to be a promising way to increase the electrochemical performance.

• 운동영양학회지
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• 제16권1호
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• pp.11-17
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• 2012

The purposes of this study were to investigate the effects of acute exercise on blood vaspin, glucose level, and inflammatory cytokines in middle-aged women with pre-diabetes. Nineteen middle-aged women (normal women, n = 11) and women with pre-diabetes(n = 8), who were apparently healthy and not taking any medications affecting their blood pressure or blood glucose, participated. Body fatness parameters including body mass index, body fat percentage, and waist circumference were measured using a bio-impedance analyzer. Resting blood pressure was measured in duplicate, and mean values were used for the data analysis. Regardless of group assignments, all subjects participated in a 3-day consecutive walking exercise at an intensity of 65% VO_2max targeting an energy expenditure of 1200 kcal (400 kcal per day). The major outcome variables included total cholesterol, triglycerides, high-density lipoprotein cholesterol, glucose, vaspin, interleukin-6, and adiponectin levels. Unlike normal women, women with pre-diabetes had a significant improvement in the homeostatic model assessment of insulin resistance (p < 0.025) with no significant group difference in response to acute exercise. The findings suggest that acute exercise results in a significant improvement in insulin sensitivity without any change in serum vaspin levels in women with pre-diabetes.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.477-484
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• 2024

Experimental investigations on gamma - rays attenuation parameters and dielectric spectroscopic properties were done on a polymeric mixture with chemical composition (100-x) polyethylene + x basalt, where x = 0, 1, 3, 5, 10, and 20 wt%. Using the melting blending technique,six nanocomposite polymeric samples were prepared. The linear attenuation coefficient µ of each prepared set of samples was measured using a gamma-ray spectrometer including High Purity Germanium detector (HPGe) at energies 662.5, 1173.24, and 1332.51 keV. Based on the measured values of (µ) and sample density, the other effective shielding parameters were calculated. The values of µ showed an increase with increasing the dopant ratios from 0.0 up to 20.0 wt%. In addition, the µ values decreased with the photon's energy. The µ values were found 0.0847 up to 0.1175 cm^-1, 0.0571 up to 0.0855 cm^-1, and 0.0543 up to 0.075 cm^-1 at 662.5, 1173.24, and 1332.51 keV. for B0 up to B20, respectively. The ATR spectroscopy was done on the prepared samples, and a good evidence of adding the filler to the pure polyethylene (HDPE) was obtained. Besides, an enhancement in dielectric constant by insertion of basalt NPs also recorded and can be attributed to the large dielectric constant of basalt compared to pure HDPE.

• 한국전기전자재료학회논문지
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• 제30권5호
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• pp.263-269
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• 2017

A piezoelectric cantilever energy harvester (PCEH) driven in longitudinal (3-3) vibration mode was fabricated, and its electrical properties were evaluated by varying the resistive load. A commercial PZT piezoelectric ceramic with a high piezoelectric charge constant ($d_{33}$) of 520 pC/N and the interdigitated (IDT) electrode pattern was used to fabricate the PCEH driven in longitudinal vibration. The IDT Ag electrode embedded piezoelectric laminates were co-fired at $850^{\circ}C$ for 2 h. The 3-3 mode PCEH was successfully fabricated by attaching the piezoelectric laminates to a SUS304 elastic substrate. The PCEH exhibited a high output power of 3.8 mW across the resistive load of $100k{\Omega}$ at 100 Hz and 1.5 G. This corresponds to a power density of $10.3mW/cm^3$ and a normalized global power factor of $4.56mW/g^2{\cdot}cm^3$. Given the other PCEH driven in transverse (3-1) vibration mode, the 3-3 mode PCEH could be better for vibration energy harvesting applications.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.768-775
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• 2017

Energy harvesting characteristics of trapezoidal piezoelectric cantilever generator, which has a lead zirconate titanate (PZT) laminate film, were compared by longitudinal (3-3) and transverse (3-1) modes. The PZT laminate film, fabricated by a conventional tape casting process, was cofired with Ag electrode at $850^{\circ}C$ for 2 h. A multi-layered Ag electrode by a planar pattern and an interdigitated pattern was applied to the PZT laminate to implement the 3-3 and 3-1 modes, respectively. The energy harvesting performance of the 3-3 mode trapezoidal piezoelectric cantilever generator was better than that of the 3-1 mode. An extremely high output power density of $26.7mW/cm^3$ for the 3-3 mode was obtained at a resonant frequency of 145 Hz under a load resistance of $50{\Omega}$ and acceleration of 1.3 G, which is ~3-times higher than that for the 3-1 mode. Therefore, the 3-3 mode is considered significantly efficient for application to high-performance piezoelectric cantilever generator.

• 한국전기전자재료학회논문지
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• 제31권4호
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• pp.216-220
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• 2018

The piezoelectric properties of $0.65Pb(Zr_{1-x}Ti_x)O_3-0.35Pb(Zn_{1/6}Ni_{1/6}Nb_{2/3})O_3$ ($PZT_x-PZNN$) ceramics with $0.530{\leq}x{\leq}0.555$ were investigated for application to piezoelectric energy harvesters. Although a morphotropic phase boundary (MPB) was found at approximately x = 0.545, the ceramic with the highest figure of merit (FOM) ($d_{33}{\times}g_{33}$) was observed at a composition of x = 0.540. Values of this figure of merit, $d_{33}{\times}g_{33}$, of $19.6pm^2/N$ and $20.2pm^2/N$ were obtained from $PZT_{0.540}-PZNN$ ceramics sintered at $920^{\circ}C$ and $950^{\circ}C$, respectively. A high output power of $937{\mu}W$ and a high power density of $3.3mW/cm^3$ were obtained from unimorph-type piezoelectric energy harvesters fabricated using $PZT_{0.540}-PZNN$ ceramic sintered at $920^{\circ}C$ for 4h.

• 한국방사선학회논문지
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• 제12권7호
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• pp.833-844
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• 2018

골다공증의 진단에서 이중에너지 X선 흡수계수법은 가장 빈번하게 사용되는 검사이다. 외국의 골밀도 장치 제조사인 지이나 홀로직 장치에 대한 교차분석 연구는 다양하나 국내 제조사 이중에너지 X선 흡수골밀도 장치에 대한 비교 분석이 부족하다. 이에 본 연구에서는 국내 제조사의 이중에너지 X선 흡수골밀도 장치와 해외 제조사의 이중에너지 X선 흡수 골밀도 장치의 교차분석을 시행하여 교차식을 수립하였다. 유럽인 척추 팬텀을 이용한 검사에서 가장 높은 표준 편차를 보인 Dexxum T 장치의 경우 상. 중. 하부 척추에서0.030, 0.029, 0.037를 보였고, 홀로직의 Horizon Ci에서는 0.005와 0.004로 하부와 중간 척추에서 가장 낮은 표준편차를 나타냈다. 오스테오 프로맥스 장치의 경우 상부 척추에서 0.005의 표준편자를 나타냈다. 본 연구에서 도출한 국내 외 이중에너지 흡수 골밀도 장치의 교차식은 임상환경에서 골밀도 검사의 추척검사에 유용한 사례가 될 것이다. 또한 본 연구에서 제시한 국산 이중에너지 X선골밀도 장치에 대해 설정된 교차 방정식에 기초로 임상환경에서 보다 정확한 골밀도 추적 관찰을 위해 보다 다양한 국산 이중에너지 X선 골밀도 장치의 교차 보정을 설정하는 것이 필요하다.

• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.148-158
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• 2022

The electrochemical CO₂ reduction (ECR) to produce value-added fuels and chemicals using clean energy sources (like solar and wind) is a promising technology to neutralize the carbon cycle and reproduce the fuels. Presently, the ECR has been the most attractive route to produce carbon-building blocks that have growing global production and high market demand. The electrochemical CO₂ reduction could be extensively implemented if it produces valuable products at those costs which are financially competitive with the present market prices. Herein, the electrochemical conversion of CO₂ obtained from flue gases of a power plant to produce diesel and formic acid using a consistent techno-economic approach is presented. The first scenario analyzed the production of diesel fuel which was formed through Fischer-Tropsch processing of CO (obtained through electroreduction of CO₂) and hydrogen, while in the second scenario, direct electrochemical CO₂ reduction to formic acid was considered. As per the base case assumptions extracted from the previous outstanding research studies, both processes weren't competitive with the existing fuel prices, indicating that high electrochemical (EC) cell capital cost was the main limiting component. The diesel fuel production was predicted as the best route for the cost-effective production of fuels under conceivable optimistic case assumptions, and the formic acid was found to be costly in terms of stored energy contents and has a facile production mechanism at those costs which are financially competitive with its bulk market price. In both processes, the liquid product cost was greatly affected by the parameters affecting the EC cell capital expenses, such as cost concerning the electrode area, faradaic efficiency, and current density.