• Korean Journal of Crystallography
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• v.6 no.2
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• pp.118-124
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• 1995

The crystal structure of an iodine sorption complex of vacumm-dehydrated Ag+ and Ca2+ exchanged zeolite A(a=12.174(3)Å) has been determined at 21℃ by single-crystal X-ray diffraction techniques in the cubic space group Pm3m. The crystal was prepared by flow method for three days using exchange solution in solution in which mole ratio of AgNO3 and Ca(NO3)2 was 1:150 with total concentration of 0.05 M. The complex was prepared by dehydration at 360℃ and 2×10-6 Torr for 2 days, followed by exposure to about 14.3 Torr of iodine vaporat 80℃ for 24 hours. Full-matrix least-squares refinement converged to the final error indices of R1=0.082, R2=0.068 using 122 reflections for which I > 3σ(I). Two Ag+ ions, 1.1 Ag+ ions, and 4.45 Ca2+ ions per unit cell are located on three different three-fold axes associated with 6-ring oxygens. Two Ag+ ions per unit cell are in the large cavity, 1.399(4)Å from the (111) plane of three oxygens. Another 1.1 Ag+ ions are found at opposite sites. Six iodine molecules are sorbed per unit cell. Each I2 molecule approaches a framework oxide ion axially (O-I=3.43(2)Å, I-I=2.92Å, I-I-O;166.1(3)°), by a charge transfer complex interaction. Two Ag+ ions make a close approach to the iodine molecules (Ag-I ; 2.73(2)Å).

• 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.

• Asian Journal of Turfgrass Science
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• v.12 no.3
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• pp.183-194
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• 1998

Of crude extracts from 30 species belonging to the 21 families of medical plants, the crude extracts from Cinnamomum cassia, Paeonia moutan, Dictamnus dasycarpus showed highly antifungal activities against Rhizoctonia solani AG1-1 and R. solani AG2-2. The antifungal activity of C. cassia and P. moutan against R. solani AG1-1 were the highest through 100% methanol extraction, but the one of D. dasycarpus were the highest through 80% methanol extraction. On the other hand, against R. solani AG2-2 the antifungal activity of them were the highest through 100% methanol. C. cassia P. mouton and D. dasycarpus showed over 60% inhibition of mycelial growth against R. solani AG1-1 and R. solani AG2-2 on up to 500 fold dilution. The crude extract of P. moutan showed broader antifungal spectrum compared with those of C. cassia and D. dasycarpus. The crude extract of C. cassia was not phytotoxic at over 250 fold dilution and the crude extract of P. moutan was not phytotoxic at over 100 fold dilution. The crude extract of D. dasycarpus was not phytotoxic even at full concentration. The control values of P. moutan and D. dasycarpus were increased 75.0% and 79.1% respectively 30 days after treatment.

• Journal of the Mineralogical Society of Korea
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• v.4 no.2
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• pp.141-146
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• 1991

Minerals of system Ag-Sb have been found in iead-zinc (-silver) ores from the Dongjeom and the Taebaeg ore deposits, which were formed at later stage of the Yeonhwa 1 mine mineralization. The Ag-Sb minerals are intergrown intimately with galena, pyrargyrite and alabandite. Their chemical compositions as determined by electron microprobe analyser show that they are chracterized by relatively high content of S, up to 5.89 atomic percent. Also the composition of the minerals may be separated into two: Ag3.89 Sb1.00-Ag7.19 Sb1.00 and Ag2.96 Sb1.00-Ag4.00 Sb1.00.

• Journal of Yeungnam Medical Science
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• v.4 no.2
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• pp.121-129
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• 1987

To evealuate the status of hepatitis B virus infection in the mothers and neonates and to determine the maternal-neonatal transmission of hepatitis B virus, 2,276 term pregnant women were screened for the presence of serum HBsAg, at the Department of Obstetrics and Gynecology, Yeungnam University Hospital, during the period of 18 months from Jan. 1986 to Jun. 1987, and the sera of sixty-six HBsAg carrier mothers and their neonates were tested for HBV markers and liver enzymes. The results were as follows : 1. The prevalence rate of asymptomatic HBsAg carrier in the term pregnant women was 4.7%(53/1,279). 2. Positive rates of HBsAg and anti-HBs 10 the sera of sixty-six neonates born to asymptomatic HBsAg carrier mothers were 12.1% and 9.1%, respectively. Transient elevation of SGOT(three to four times of upper normal limit) was detected in one of eight HBsAg-positive neonates and one of six anti-HBs positive neonates. 3. Positive rates of anti-HBc, HBeAg and anti-HBe to the sera of sixty-six asymptomatic HBsAg carrier term pregant women were 93.9%, 45.5% and 50%, respectively. The rates of transmission of maternal anti-HBc, HBeAg and anti-HBe to the neonates were 85.5%(53/62), 90%(27/30) and 87.9%(29/33). respectively. 4. Serum HBsAg was detected in four of thirty neonates born to HBeAg positive HBsAg carrier mother, three of thirty-three neonates born to anti-HBe positive HBsAg carrier mothers, and one of three neonates born to both HBeAg and anti-HBe negative HBsAg carrier mothers.

• The korean journal of orthodontics
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• v.47 no.1
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• pp.3-10
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• 2017

Objective: Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods: AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results: SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions: Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial.

• Clinical and Experimental Pediatrics
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• v.45 no.6
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• pp.727-731
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• 2002

Purpose : The objectives of this study are to evaluate the significance of HBeAg positivity in infants born to HBeAg and HBsAg positive mothers. Methods : The HBeAg status of 22 HBeAg positive, HBsAg negative infants born to HBeAg and HBsAg positive mothers from December 1996 to March 1999 were evaluated by enzyme immunoassay. Results : The number of HBsAg positive carrier mothers was 213(4.9%) out of 4,338 pregnant women. HBeAg was positive in 76(41.5%) out of 183 HBsAg positive mothers. Only 49 infants born to 76 HBeAg positive mothers could be evaluated; 36 infants were HBeAg positive and HBsAg negative. Laboratory follow up was possible in 22 infants. HBeAg disappeared in 7 cases within two months and in 20 cases within 12 months(over 90%). Ultimately, twenty-two babies who were HBsAg-negative and HBeAg-positive became negative for HBeAg, however, one showed HBsAg in follow up of 6 months of age. Conclusion : HBeAg positivity in infants born to HBeAg positive mothers may result from the maternofetal transmission and this HBeAg eventually disappeared without clinical significance.

• Bulletin of the Korean Chemical Society
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• v.9 no.6
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• pp.338-341
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• 1988

Two crystal structures of fully dehydrated silver and potassium exchanged zeolite A, stoichiometries of $Ag_{9.3}K_{{2.7}^-}A$ (${\alpha}$ = 12.282(2) ${\AA}$) and $Ag_{10.7}K_{{1.3}^-}{\AA}$ (${\alpha}$ = 12.287(2) A) per unit cell, have been determined from 3-dimensional x-ray diffraction data gathered by counter methods. All structures were solved and refined in the cubic space group Pm3m at 21(1)$^{\circ}C$ . The crystals of $Ag_{9.3}K_{{2.7}^-}A$ and $Ag_{10.7}K_{{1.3}^-}A$ were prepared by flow method using exchange solutions in which mole ratios of $AgNO_3$ and $KNO_3$ were 1:10 and 1:5, respectively, with total concentration of 0.05M. The structures of the dehydrated $Ag_{9.3}K_{{2.7}^-}A$ and $Ag_{10.7}K_{{1.3}^-}A$ were refined to yield the final error indices $R_1$ = 0.037 and $R_2$ = 0.040 with 321 reflections, and $R_1$ = 0.042 and $R_2$ = 0.043 with 371 reflections, repectively, for which I > 3${\sigma}$(I). In both structures, eight $Ag^+$ ions are found nearly at 6-ring centers and each $Ag^+$ ion is nearly in the (1 1 1) plane at its O(3) ligands. The 8-ring sites are preferentially occupied by $K^+$ ions in both structures. 1.3 and 1.7 reduced silver atoms per unit cell were found inside of sodalite units of $Ag_{9.3}K_{{2.7}^-}A$ and that of $Ag_{10.7}K_{{1.3}^-}A$, respectively. These reduced silver species were presumably formed from the reduction of $Ag^+$ ions by oxide ions of residual water molecule or of the zeolite framework. These two crystals may be presented as hexasilver cluster in 21.7% and 28.3% of sodalite unit cells for $Ag_{9.3}K_{{2.7}^-}A$ and $Ag_{10.7}K_{{1.3}^-}A$, repectively.

• Current Photovoltaic Research
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• v.3 no.1
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• pp.16-20
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• 2015

Ag addition in chalcopyrite materials is known to lead beneficial changes in aspects of structural and electronic properties. In this work, the effects of Ag alloying of $Cu(In,Ga)Se_2$-based solar cells has been investigated. Wide bandgap $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x = 0.75~0.8) films have been deposited using a three-stage co-evaporation with various Ag/(Ag+Cu) ratios. With Ag alloying the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films were found to have greater grainsize and film thickness. Device were also fabricated with the $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ (x~0.8) films and their J-V and quantum efficiency measurements were carried out. The highest-efficiency $(Ag,Cu)(In_{1-x},Ga_x)Se_2$ solar cell with Eg > 1.5 eV had an efficiency of 12.2% with device parameters $V_{OC}=0.810V$, $J_{SC}=21.7mA/cm^2$, and FF = 69.0%.

• Resources Recycling
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• v.27 no.2
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• pp.48-54
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• 2018

Batch ion exchange experiments of Au(III) were performed from ammonium chloride solution by employing strong anionic exchange resins (Amberlite IRA 402 and AG 1-X8). Au(III) was well loaded into the two resins and the loading behavior of Au(III) into AG 1-X8 was superior to that into Amberlite IRA 402. The loading of Au(III) into AG 1-X8 followed Langmuir adsorption isotherm and the experimentally determined loading capacity was 355 mg/g. Au(III) was successfully eluted by $HClO_4$ from the loaded AG 1-X8 and the elution percentage of Au(III) increased with the concentration of $HClO_4$.