• Journal of IKEEE
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• v.21 no.3
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• pp.284-287
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• 2017

In this study, we examined the simulated electrical characteristics of single-gated feedback field effect transistors (FBFETs) and the influence of channel length variation of the memory window characteristics through the 3D device simulation. The simulations were carried out for various channel lengths from 50 nm to 100 nm. The FBFETs exhibited zero SS(< 1 mV/dec) and a current $I_{on}/I_{off}$ ratio${\sim}1.27{\times}10^{10}$. In addition, the memory windows were 0.31 V for 50 nm-channel-length devices while no memory windows were observed for 100 nm-channel-length devices.

• Journal of the Korean Chemical Society
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• v.32 no.4
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• pp.301-310
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• 1988

Reaction rates for mononuclear heterocyclic rearrangement of N-(5-phenyl-1,2,4-oxadiazol-3-yl)-N'-arylformamidines into 3-acylamino-1-aryl-1,2,4-triazoles were determined spectrophotometrically in dioxane/water (50 : 50, v/v). There are two different reaction paths according to pH. One is pH-independent path, the other is pH-dependent one. In pH-independent path, the result of substituent effect by IYT equation show that N-H bond breaking as well as new N-N bond formation controls the reaction rate. In pH-dependent path, concave-upward Hammett plot was observed. It can be concluded that new N-N bond formation is more advanced than N-H bond breaking in transition state for electron-donating substituents, but N-H bond breaking is more advanced than new N-N bond formation for electron-withdrawing substituents.

• Journal of Korean Society of Forest Science
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• v.90 no.1
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• pp.55-63
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• 2001

Populus euramericana and Betula platyphylla var. japonica have been identified as possible species for use for phytoremediation of landfills. To identify the effects of waste leachate on growth and physiological characteristics in Populus euramericana and Betula platyphylla var. japonica, four different treatments were applied to seedlings for 3 months: leachate solution(100% leachate), 50% dilution(50% leachate: 50% water, v/v), 75% dilution(25% leachate: 75% water, v/v) and control(tab water) were applied to these two species. Treatment with waste leachate significantly stimulated both Populus euramericana and Betula platyphylla var. japonica height, diameter at root collar and biomass production relative to the water control. Chlorophyll contents, photosynthesis and transpiration of leachate irrigated-trees were significantly higher than those of water control. These results suggested that these two species could be suitable species for phytoremediation in landfills because these species showed good growth performance and were capable of taking up waste leachate.

• Geophysics and Geophysical Exploration
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• v.17 no.1
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• pp.11-20
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• 2014

To reveal shear-wave velocities ($v_s$) and site characterization of Wonju, Korea, Rayleigh waves were recorded at 78 sites of lower altitude using 12 to 24 4.5-Hz vertical geophones for 20 days during the period of February to September 2013. Dispersion curves of the Rayleigh waves obtained by the extended spatial autocorrelation method were inverted using the damped least-squares method to derive $v_s$ models. From these 1-D models, the average $v_s$ to a depth of 30 m ($v_s30$), $v_s$ of weathered rocks, depths to these basement rocks, and average $v_s$ of the overburden layer were derived to be $16.3{\pm}0.7m$, $576{\pm}8m/s$, $290{\pm}7m/s$, and $418{\pm}13m/s$, respectively, in the 95% confidence range. To determine adequate proxies for $v_s30$, we computed correlation coefficients of $v_s30$ with topographic slope (r = 0.46) and elevation (r = 0.43). An empirical linear relationship is presented as a combination of individually estimated $v_s30$ with weighting factors of 0.45, 0.45, and 0.1 for topographic slope, elevation, and mapped lithology, respectively. Due to a weak correlation between $v_s30$ obtained from inversion of dispersion curves and the proxy-based estimation (r = 0.50), however, the relatively large error range should be considered for applications of this relationship.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1657-1662
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• 2014

In this paper, the impact of substrate bias($V_{BS}$) on the zero capacitor RAM(Z-RAM) in n-channel junctionless multiple gate MOSFET(MuGFET) has been analyzed experimentally. Junctionless transistors with fin width of 50nm and 1 fin exhibits a memory window of 0.34V and a sensing margin of $1.8{\times}10^4$ at $V_{DS}=3.5V$ and $V_{BS}=0V$. As the positive $V_{BS}$ is applied, the memory window and sensing margin were improved due to an increase of impact ionization. When $V_{BS}$ is increased from 0V to 10V, not only the memory window is increased from 0.34V to 0.96V but also sensing margin is increased slightly. The sensitivity of memory window with different $V_{BS}$ in junctionless transistor was larger than that of inversion-mode transistor. A retention time of junctionless transistor is better than that of inversion-mode transistor due to low Gate Induced Drain Leakage(GIDL) current. To evaluate the device reliability of Z-RAM, the shifts in the Set/Reset voltages and current were measured.

• Korean Journal of Food Science and Technology
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• v.44 no.3
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• pp.373-377
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• 2012

This study was carried out in order to investigate the functional properties of 50% methanol extracts from four parts (root, stem, leaf and fruit) of Acanthopanax sessiliflorus by means of measuring the contents of eleutheroside B, E, and total polyphenols as well as determining electron donating ability (EDA), nitrite scavenging ability (NSA), and anticancer activity. The highest contents of eleutheroside B and E were found in the fruit (538.99 ${\mu}g/g$) and the stem (556.00 ${\mu}g/g$). The root extract demonstrated the highest polyphenol content (2.97 mg/g). EDA of the stem and root extracts were 90.21% and 85.71%. All of the extracts showed 81.5-93.0% of NSA at pH 1.2. In addition all extracts indicated no cytotoxicity to normal cell line (DC2.4). The root extract had a 23% inhibitory effect against the stomach cancer cell line (SNU-719). These results revealed that 50% methanol extracts from A. sessiliflorus can be used as a potential resource of nutraceuticals.

• Journal of Pharmacopuncture
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• v.25 no.3
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• pp.242-249
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• 2022

Objectives: The aim of this work is to evaluate the in vitro antioxidant, hypoglycemic, and antiobesity effects of Euphorbia resinifera extracts and investigate the phenolic constituents and the toxicity of these extracts. Methods: Phytochemical screening was performed to detect polyphenols and flavonoids. Antioxidant activity was evaluated by four methods (DPPH, ABTS, H₂O₂, and xanthine oxidase inhibition). The hypoglycemic effect was determined by the inhibition of α-amylase and α-glucosidase enzymes in vitro and via a starch tolerance study in normal rats. The antiobesity effect was estimated by in vitro inhibition of lipase. Results: Phytochemical screening revealed that the ethanolic extract was rich in polyphenols (99 ± 0.56 mg GEA/g extract) and tannins (55.22 ± 0.17 mg RE/g extract). Moreover, this extract showed higher antioxidant activity in different tests: the DPPH assay (IC₅₀ = 53.81 ± 1.83 ㎍/mL), ABTS assay (111.4 ± 2.64 mg TE/g extract), H₂O₂ (IC₅₀ = 98.15 ± 0.68 ㎍/mL), and xanthine oxidase (IC₅₀ = 10.26 ± 0.6 ㎍/mL). With respect to hypoglycemic effect, the aqueous and ethanolic extracts showed IC₅₀ values of 119.7 ± 2.15 ㎍/mL and 102 ± 3.63 ㎍/mL for α-amylase and 121.4 ± 1.88 and 56.6 ± 1.12 ㎍/mL for α-glucosidase, respectively, and the extracts lowered blood glucose levels in normal starch-loaded rats. Additionally, lipase inhibition was observed with aqueous (IC₅₀ = 25.3 ± 1.53 ㎍/mL) and ethanolic (IC₅₀ = 13.7 ± 3.03 ㎍/mL) extracts. Conclusion: These findings show the antioxidant, hypoglycemic, and hyperlipidemic effects of E. resinifera extracts, which should be investigated further to validate their medicinal uses and their pharmaceutical applications.

• Biomolecules & Therapeutics
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• v.3 no.2
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• pp.116-121
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• 1995

Some multidrug resistance inhibitors have been known to be influenced by the serum concentration. In this study, effect of serum concentration on inhibition of nucleoside transport by BIBW22, a new multidrug resistance inhibitor derived from dipyridamole (DPM), was studied. When 5% or 100% (v/v) of fetal bovine serum (FBS) was contained in the culture, DPM dose for which nucleoside transport was inhibited by 50% (lD$_{50}$) was 0.42 $\mu$M or 1.17 $\mu$M, respectively. BIBW22 also showed the same trend as DPM did in response to increase of FBS concentration. However, ID$_{50}$ value for DPM in the absence or presence of human plasma was 0.007 $\mu$M or 1.02 $\mu$M respectively showing 145 times increase of ID$_{50}$ value. ID$_{50}$ value for BIBW22 in the presence of human plasma was 0.028 $\mu$M showing only 5 times increase in ID$_{50}$ value. This result suggests that potency of BIBW22 was much less affected by the plasma concentration and BIBW22 could be a good candidate for a clinical use in multidrug resistance treatment.treatment.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.428-433
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• 1973

The quantitative separations of a mixture containing equal amount of each anion such as Si(IV), As(V), P(V), S(VI), W(VI) and Cr(VI) are carried out by the elution through 20${\times}3.14cm^2$ column of anion exchange resin, Dowex 1${\times}$8. The eluents are a mixture of 0.07 M hydrochloric acid and 0.03 M sodium chloride (pH = 1.30) for Si(IV), As(V) and P(V) species, a mixture of 0.6 M sodium chloride and 0.3 M sodium hydroxide for S(VI), W(VI) and Cr(VI) species, and 0.1 N sodium sulfite (pH = 3.48) for P(V) and As(V) species. The subsidiary anions in a standard mixture such as Si(IV), As(V), S(VI), P(V) and W(VI) are separated together from large amount of Fe(III) by the elution through 30cm${\times}3.14cm^2$ column of the resin, Dowex${\times}$50w${\times}$12, using a mixture of 0.1 M sodium nitrate and 2 percent dimethylsulfoxide aqueous solution as an eluent. Si(IV), As(V), S(VI), P(V) and W(VI) eluted together are separated quantitatively under the same conditions as in the separations of the anion mixture. By the conditions obtained in the separations of the standard mixture, Fe(III) and all of the subsidiary anions in steel are quantitatively separated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.253-259
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• 2005

In this paper, BaSrTiO$_{3}$(BST) thin film tunable interdigital capacitor using low cost silicon substrate instead of expensive single-crystalline substrate is presented. The tunable capacitor in which BST thin film is deposited by PLD has operation frequency and applied bias up to 4 GHz and 50 V, respectively. The maximum tunability in capacitance is found to be 30$\%$, for an applied field of 5 kV/cm at a bias of 50 V. Therefore, it has been shown that the BST microwave tunable capacitor can be integrated onto Si substrate.