• Analytical Science and Technology
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• v.11 no.4
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• pp.248-253
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• 1998

The adsorption and separation behaviors of alkali, alkaline earth and transition metal ions using a poly-dibenzo-18-crown-6 were investigated in aqueous solution. The adsorption degree(E) and distribution ratio(D) of alkali, alkaline earth metal ions were Li(I)$t_R$) of metal ions were affected by the adsorption degree(E) and distribution ratio(D). This results showed good separation efficiency of K(I), Sr(II), Ag(I) and Pb(II) from the mixed metal solution.

• The Journal of the Acoustical Society of Korea
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• v.35 no.6
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• pp.427-435
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• 2016

Array Gain (AG) is a metric to measure the performance of an array of acoustic sensors. AG is affected by the configuration of array, frequency and array element spacing, and the directivity of the ambient noise. In this paper, an algorithm to calculate AG based on the spatial coherence is used, and the results are verified through sea-going experiment. The method using the spatial coherence can be used to consider the arbitrary shape of an array and directionality of ambient noise. In the sea-going experiment, the towed source was used to transmit the Continuous Wave (CW), and was received at the horizontal line array on the seabed. The ambient noise was measured between the source transmission. The experimental AG was calculated from the SNR (Signal to Noise Ratio) of single sensor and an array of sensors. Finally, the predicted AG is shown to agree with the experimental value of AG.

• Journal of Acupuncture Research
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• v.34 no.3
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• pp.1-11
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• 2017

Objectives : The purpose of this study was to examine the effects of Acori Graminie Rhizoma Pharmacopuncture (PA-AG) at GV20 on cerebral ischemia-induced dementia in Mice. Methods : Mice were divided into the five following groups: normal, control, acupuncture, PA-AG (17 mg/kg), and PA-AG (34 mg/kg). All groups, except the normal group, had cerebral ischemia induced by occlusion of middle cerebral artery. The control group was not treated. The acupuncture, PA-AG (17 mg/kg), and PA-GA (34 mg/kg) groups were treated every other day with a total of 6 treatments. The effect of treatment was observed by Bax, Bcl-2, Bax/Bcl-2 ratio, cytochrome c, cresyl violet, and choline acetyltransferase staining. Results : In the PA-AG (34 mg/kg) group, the intensity of Bax was decreased and the intensity of Bcl-2 was increased. The Bax/Bcl-2 ratio also decreased in the PA-AG (34 mg/kg) group. The intensity of cytochrome c protein stain was decreased in the PA-AG (17 mg/kg) group. The density of neurons stained by cresyl violet and choline acetyltransferase (ChAT) was increased in the AT, PA-AG (17 mg/kg), and PA-AG (34 mg/kg) groups when compared with that of the control group. Conclusion : PA-AG at GV20 was effective on cerebral ischemia-induced dementia in mice.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.36-44
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• 2023

Core-shell TiO₂/Ag nanoparticles were synthesized by a modified sol-gel process and the reverse micelle method using acetoxime as a reducing agent in water/dodecylbenzenesulfonic acid (DDBA)/cyclohexane. The structure, shape, and size of the TiO₂/Ag nanoparticles were investigated using X-ray diffraction (XRD), UV-visible spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), and thermogravimetric analysis (TGA). The size of TiO₂/Ag nanoparticles could be controlled by changing the [water]/[DDBA] molar ratio values. The size and the polydispersity of TiO₂/Ag nanoparticles increased when the [water]/[DDBA] molar ratio rose. The resultant Ag nanoparticles over the anatase crystal TiO₂ nanoparticles exhibited a strong surface plasmon resonance (SPR) peak at about 430 nm. The SPR peak shifted to the red side with the increase in nanoparticle size. Conductive pastes with 70 wt% TiO₂/Ag nanoparticles were prepared, and the pastes were coated on the PET films using a screen-printing method. The printed paste films of the TiO₂/Ag nanoparticles demonstrated greater surface resistance than conventional Ag paste in the range of 405~630 μΩ/sq.

• Resources Recycling
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• v.5 no.1
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• pp.29-33
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• 1996

The cominnn plocesses lor rccoremg silver irom silvcr conlaincd waster are the lcachmg silver hy HNO;. the srlcctive precipilillion of sliver ion lo AgCl and thc rcduchon of Ag wrfh ;I proper reductant. In this sludy, thc reduction of AgCI lo Ag was invesllngated by using Na, CO, as a rcd\icta~lt. The variations wcic reaction time. ttmpcrarure thc amount of NalCO, . and the resulls %, ere analyzcd by using sialist~c:d tecl~niques such as the ]polynomial rcgressiun analysis and the response surh~ce method. More than Yh% Ag analyzed was rcduced 1rtm AgCI at 62UT. I hour ullder condillon of 2 stnlchio~nctric ratio of Na iCO, !AgCI.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.7
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• pp.517-520
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• 2010

Lead-free $0.9(Na_{0.52}K_{0.48})NbO_3$ - $0.1LiTaO_3$ piezoelectric ceramics doped with $Ag_2O$ (0-4 mol%) have been prepared by the conventional mixed oxide method. The structural and electrical properties were analyzed in order to find its potential applications. The crystal structure of 1-4 mol% Ag doped $0.9(Na_{0.52}K_{0.48})NbO_3$-$0.1LiTaO_3$ lead free piezoelectric ceramics were investigated for several sintering temperatures ($1100^{\circ}C$) by the use of X-ray diffraction analysis. In order to analyze the effect of Ag dopants on the $0.9(Na_{0.52}K_{0.48})NbO_3$-$0.1LiTaO_3$ ceramic, the diffraction intensity ratio of the (002) to (200) planes were calculated from the X-ray diffraction patterns of the ceramic samples.

• Journal of Acupuncture Research
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• v.35 no.1
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• pp.21-27
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• 2018

Background: Examination of the effects of deer antler, old antler, and antler glue on postmenopausal osteoporosis in an ovariectomized Sprague-Dawley rat model. Methods: The study involved 7 experimental groups; SHAM (sham-operated rats), OVX (ovariectomized rats), E2 (ovariectomized rats with estradiol $10{\mu}g/kg$ daily, orally), DA (ovariectomized rats with deer antler extract 5.83 mg/kg), OA (ovariectomized rats with old antler extract 3.8 mg/kg), low-AG (ovariectomized rats with low dose of antler glue powder 12.5 mg/kg), high-AG (ovariectomized rats with high dose of antler glue powder 37.5 mg/kg). After 6 weeks of treatment, body weight, blood calcium, phosphorus, estradiol, liver [alkaline phosphatase (ALP), aspartate transaminase (AST), alanine transaminase (ALT)] and kidney [blood urea nitrogen (BUN)/creatinine ratio] function, and femoral bone mineral density (BMD) were measured. Results: The body weights of DA, OA, low-AG, and high-AG groups did not significantly differ from OVX group. Blood estradiol levels were significantly increased in the DA, low-AG, and high-AG groups compared to the OVX group. Blood calcium, phosphorus, ALP, AST, and ALT levels and BUN/creatinine ratio did not show significant changes in the DA, OA, low-AG, and high-AG groups. BMDs of the femur, and femoral head and neck were significantly increased in the low-AG group. In the OA group, the BMD of the femoral head and neck was significantly increased. Conclusion: Treatment with deer antler, or antler glue for 6 weeks was effective for increasing estradiol and femoral BMD in ovariectomized rats, suggesting that this may be of therapeutic benefit for osteoporosis.

• Journal of the Korean Magnetics Society
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• v.6 no.3
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• pp.189-193
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• 1996

Magnetoresistance field sensitivity and magnetostriction were measured as a function of annealing temperature for NiFe/Ag multilayer systems displaying giant magnetoresistance. Key multilayer configurations such as number of NiFe/Ag bilayers and Ag spacer thickness were varied. A high giant magnetoresistance ratio up to 5% with zero magnetostriction and high magnetoresistance field sensitivity was possible to achieve simultaneously with optimal sample geometry and annealing condition.

• Journal of the Korean Chemical Society
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• v.47 no.4
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• pp.315-324
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• 2003

In this study, a new method is presented to produce stable hydrophobic metal alloy nanocluster in chloroform solution including surfactant NaAOT(sodium bis(2-ethylhexyl)-sulfosuccinate) via the chemical reduction of metal salt $(HAuCl_4,\AgNO_3,\Cu(NO_3)_2)$ by sodium borohydride. For the alloy nanocluster, several samples were prepared by changing the molar ratio of Au/Cu, Au/Ag alloy nanocluster, 3:1, 1:1, 1:3. The alloy nanoclusters were characterized by UV-Visible spectrophotometer, TEM(Transmission Electron Microscope), and XPS(X-ray Photoelectron Spectrometer). With the change of the mole ratio of the alloy component, the wavelengths of the surface plasmon absorption shift linearly from 520 nm of the pure Au nanocluster to 570 nm of the pure Cu nanocluster for Au/Cu alloy nanoclusters and from 405 nm to 520 nm for Au/Ag alloy nanoclusters. The chemical shifts of the Au4f, Ag3d, Cu2p XPS peaks were observed with changing the molar ratio of the alloy element. The alloy nanoclusters in chloroform solution were made uniformly in size and colloidally stable for long periods of time. These results indicate that the method here is a very effective method for synthesizing hydrophobic alloy nanoclusters with uniform or nearly uniform particle size distribution.

• Membrane Journal
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• v.24 no.6
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• pp.417-422
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• 2014

The poly(ethylene oxide) (PEO)/Ag Nanoparticles (NPs)/7,7,8,8-Tetracyanoquinodimethane (TCNQ) membrane was fabricated to obtain highly permeable facilitated olefin transport nanocomposite membrane, compared with PEO/Ag NPs/p-Benzoquinone (p-BQ) membrane. Polymer matrix, PEO and silver nanoparticle precursor $AgBF_4$ were fixed at 1 : 0.4 mole ratio and electron acceptor TCNQ content was controlled variously. And the best olefin separation performance was obtained at 1/0.4/0.004 mole ratio, and long-term separation performance was measured at this ratio. As a result, mixed-gas permeance decreased from 23 to 6 GPU, and selectivity decreased from 6 to 2 (propylene/propane) after 32 hours.