• Journal of the Korean Chemical Society
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• v.20 no.6
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• pp.486-493
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• 1976

The PVC mixed silver iodide pellet was prepared by means of the Infrared Pellet presser and the pellet was used as an indicating membrane electrode, to measure the potentials for various silver ion activities, ranging from $10^{-1}$ to $10^{-6}$ M. The potential responses to silver ion activities were linear and the slope was much close to Nernstian relation as compared with that of the pure silver iodide pellet membrane electrode and the PVC coated silver iodide pellet membrane electrode. The mechanical property and chemical durability of this electrode were found much better than the others. This electrode did not show significant response to the other except silver ion, but had good response to halide ions, i.e., iodide, chloride, bromide and cyanide ions, in the concentration range $10^{-1}$ to $10^{-6}$ M. This electrode could be used as an indicating electrode in potentiometric titrations of single halide ion and also halide mixture with standard solution of silver nitrate.

• Economic and Environmental Geology
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• v.21 no.4
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• pp.367-380
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• 1988

Most of the gold (-silver) vein deposits at Yeongdong District are mainly distributed in the precambrian metamorphic rocks. Based on the Ag/Au total production and ore grade ratios, the chemical composition of electrum and the associated sulfides, the gold(-silver) deposits at Yeongdong District may be classified into 4 classes: pyrrhotite - type gold deposits( I), pyrite - type gold deposits (IT A; massive vein), pyrite - type gold deposits (II B; nonmassive vein) and argentite - type gold - silver deposits(III). The chemical study on electrum(including native gold) revealed that Au content (2.8 to 92.4 atomic%) of electrums varies very widely for different classes of deposits. The Au content of electrum associated with pyrrhotite (Class I), ranging from 47.1 to 92.4 atomic% Au, is clearly higher than that associated with pyrite (Classes IIA, IIB and III). In contrast, classes I, II, and III deposits do not show clear differences in Au content of electrum. In general, pyrrhotite - type gold deposits(I) are characterized by features such as simply massive vein morphology, low values in the Ag/Au total production and ore grade ratios, the absence or rarity of silver - bearing minerals except electrum, and distinctively simple mineralogy. Although the geological and mineralogical features and vein morphology of pyrite - type gold deposits(IIA)are very similar to those of pyrrhotite - type gold deposits (I), Class II A deposits reveal significant differences in the associated iron sulfide (i. e. pyrite) with electrum and Au content of electrum. The Ag/Au total production and ore grade ratios from Class II A deposits are relatively slightly higher than those from Class I deposits. Pyrite - type gold deposits(II B) and argentite - type gold - silver deposits (III) have many common features; complex vein morphology, medium to high values in the Ag/Au total production and ore grade ratios and the associated iron sulfide (i. e. pyrite). In contrast to Class II B deposits, Class III deposits have significantly high Ag/Au total production and ore grade ratios. It indicates distinct difference in the abundance of silver minerals (i. e. native silver and argentite). The fluid inclusion analyses and mineralogical data of electrum tarnish method indicate that the gold mineralization of Classes I and II A deposits was deposited at temperatures between $230^{\circ}$ and $370^{\circ}C$, whereas the gold (-silver) mineralization of Classes ITB and ill formed from the temperature range of $150^{\circ}-290^{\circ}C$. Therefore, Classes I and IT A deposits have been formed at higher temperature condition and/or deeper positions than Classes IIB and III.

• Journal of the Korean Ceramic Society
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• v.38 no.12
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• pp.1104-1109
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• 2001

Samples with the nominal composition, B $i_{1.84}$P $b_{0.34}$S $r_{1.91}$C $a_{2.03}$C $u_{3.06}$ $O_{10+}$$\delta$/ high $T_{c}$ superconductors containing As as an additive were fabricated by a solid-state reaction method. Samples with Ag of 10wt%, 30 wt% and 50 wt% each were sintered at 86$0^{\circ}C$~875$^{\circ}C$ for 24 hours. The structural characteristics, critical temperature and grain size with respect to Ag contents were analyzed by XRD(X-ray Diffraction) and SEM(Scanning Electron Microscope), respectively. As Ag contents increased, XRD peaks of g in Bi-2223 phase superconductors intensified and the proportion of the phase transition from Bi-2223 to Bi-2212 was increased.increased.

• Bulletin of the Korean Chemical Society
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• v.15 no.11
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• pp.940-944
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• 1994

The crystal structure of an ethylene sorption complex of dehydrated $Ag_{12}-A $reacted with bromine vapor has determined by single-crystal X-ray diffraction techniques in the cubic space group of Pm3m at 22(l)$^{\circ}$C (a=12.180(2) ${\AA}$). The crystal was prepared by dehydration of $Ag_{12}$-A at 400 $^{\circ}$C and $2 {\times} l0^{-6}$ Torr for 2 days, followed by exposure to 200 Torr of ethylene gas at 24(l) $^{\circ}$C for 1 hr. After the ethylene gas was evacuated for 1 hr, the crystal was exposed to 180 Torr of bromine vapor at 24(l) $^{\circ}$C for 1.5 h. The structure was refined to the final error indices, $R_1=0.066\;and\;R_2$ (weighted)=0.055, using 137 independent reflections for which I>3${\sigma}$I. About 55% of the sodalite unit contain two 6-ring $Ag^+$ ions and the remaining 45% contain $Ag_6$ molecules complexed to 2 $Ag^+$ ions at 6-ring sites to give $(Ag^+)_2(Ag_6).$ Upon sorption of ethylene, 4.75 ethylene molecules were sorbed per unit cell and of these, only 1.25 ethylene molecules were brominated by treatment of dibromine because of the limitation of the available space for the reaction products in the large cavity. In the large cavity, each of 3.5 $Ag^+$ ions forms a lateral ${\pi}$ complex with an ethylene molecule. About 2.5 8-ring $Ag^+$ ions per unit cell interact with 1.25 1,2-dibromoethane and each of ca. 1.25 6-ring $Ag^+$ ions also interacts with one of bromine atoms of 1,2-dibromoethane. Each bromine atom approaches a carbon atom with C-Br(l)=2.07(20) ${\AA}$ and C-Br(2)=2.07(10) ${\AA}$, respectively.

• Journal of Preventive Medicine and Public Health
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• v.17 no.1
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• pp.203-210
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• 1984

Primary screening test for serum HBsAg by RPHA from 4,805 persons who were clinically well through preemployment examination for the period of one calendar year of 1983 revealed 476 (9.9%) positive individual carriers. There were no significant differences in distribution of positives of serum HBsAg by age group, profession, or province area. Among positives of serum HBsAg, 356 (74.8%) showed normal findings and 120 (25.2%) showed abnormal findings in liver function test, respectively. Radioimmunoassay was done in 169 positives of HBsAg and RIA detected 10 negative persons who were positive by RPHA revealing 5.9% of false positive rate and 94.1% of sensitivity of RPHA. In RIA profile of HBV markers, pattern I (HBsAg+, Anti-HBe+) was 46.6%, pattern II (HBsAg+, HBeAg+) was 33.3%, pattern III (HBsAg+only) was 18.3%, pattern IV (HBsAg+, HBeAg+, Anti-HBs+) was 1.3%, pattern V (HBsAg+, HBeAg+, Anti-HBe+) was 0.6%, respectively. There were no positives of HBsAg among 10 persons who were negatives of HBsAg by RIA.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.852-858
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• 2007

The dependence of substrate on the Ag photodoping phenomenon into amonhous $({\alpha}-)$ GeSe thin film has been investigated using holographic method. A 442 nm HeCd laser was utilized as a light source for the holographic exposure and a 632.8 nm HeNe laser to measure the variation of diffraction efficiency $(\eta)$ in real time. The films (Ag and ${\alpha}-GeSe$) were thermally deposited on the substrates, i.e. p-type Si(100), n-type Si(100) and slide glass. The sample structures prepared were two types: type I (Ag/${\alpha}$-SeGe/substrate) and type II (${\alpha}$-SeGe/Ag/substrate). The $\eta$ kinetics comprised to be three steps in which $\eta$ initially increases, is saturated to be maximized $(\eta_M)$, and then decreases relatively gradually. For the same substrate, the $\eta_M$ values of the type II were higher than those of type I. In addition, the type II exhibited the highest $\eta_M$ for p-type Si substrate, while that in type I was observed for n-type Si substrate. These tendency is explained by the diffusion of minority carrier in the films and the change of magnitude and direction in internal fields generated at the film interfaces. Atomic-force-microscope (AFM) was used to observe relief-type grating patterns.

• Journal of the Korean Chemical Society
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• v.38 no.9
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• pp.621-627
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• 1994

Two crystal structures of dehydrated, $Ag^{+}$ and $Ca^{2+}$-exchanged zeolite A treated at $250^{\circ}C$ with 0.15 torr of Cs vapor have been determined by single-crystal X-ray diffraction technique in the cubic space group $Pm{\bar\3m$ at $21(1)^{\circ}C$ (a = 12.344(2) $\AA$ and 12.304(2) $\AA$). Their structures were refined to the final error indices, R (weighted), of 0.091 with 180 reflections, and 0.093 with 179 reflections, respectively, for which I > $3\sigma(I).$ In each structure, Cs species are found at four different crystallographic sites: 3 $Cs^{+}$ ions per unit cell are located at 8-ring centers, ca. 6.81∼7.14 $Cs^{+}$ ions are found on opposite 6-rings on threefold axes in the large cavity, ca. 1.93∼2.03 $Cs^{+}$ ions are found on threefold axes in the sodalite unit, and 0.53∼0.66 $Cs^{+}$ ions lie on opposite 4-rings. Also, ca. 4.12∼4.27 Ag atoms are located near the center of the large cavity. In these structures, excess cesium atoms in a unit cell are associated with other $Cs^{+}$ ions on a single threefold axis to form the linear cationic cluster $(Cs_4)^{3+}$. By blocking 8-rings, the $Cs^{+}$ ions may have prevented silver atoms from migrating out of the structure. The Ag atoms are likely to have formed hexasilver clusters at the centers of the large cavities. Each hexasilver cluster is stabilized by coordination to 14 $Cs^{+}$ ions.

• Journal of the Korean earth science society
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• v.36 no.4
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• pp.301-314
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• 2015

The purpose of this study was to investigate the impact of ground-based glaciogenic seeding on orographic clouds in the Daegwallyeong area on 13 March, 2013. The experiments was conducted by releasing silver iodide (AgI) under following conditions: surface temperature below $-4^{\circ}C$, wind direction between 45 and $130^{\circ}$, and wind speed less than $5ms^{-1}$. Two seeding rates, $38gh^{-1}$ (SR1) and $113gh^{-1}$ (SR2), were tested to obtain an appropriate AgI ratio for snowfall enhancement in the Daegwallyeong area. Numerical simulations were carried out by using the WRF (Weather Research and Forecast) model with AgI point-source module which predicted dispersion fields of AgI particles. The results indicated that the target orographic clouds contained adequate amount of supercooled liquid water and that the dispersion of AgI particles tended to move along the prevailing wind direction. To validate the seeding effects, the observation data from FM-120 and MPS as well as PARSIVEL disdrometer were analyzed. In this case study, glaciogenic seeding significantly increased the concentration of small ice particles below 1 mm in diameter. The observation results suggest that SR1 seeding be reasonable to use the ground-based seeding in the Daegwallyeong area.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.31 no.2
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• pp.117-121
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• 2018

Perovskite solar cells have received increasing attention in recent years because of their outstanding power conversion efficiency (exceeding 22%). However, they typically contain toxic Pb, which is a limiting factor for industrialization. We focused on preparing Pb-free perovskite films of Ag-Bi-I trivalent compounds. Perovskite thin films with improved optical properties were obtained by applying an anti-solvent (toluene) washing technique during the spin coating of perovskites. In addition, the surface condition of the perovskite film was optimized using a multi-step thermal annealing treatment. Using the optimized process parameters, $AgBi_2I_7$ perovskite films with good absorption and improved planar surface topography (root mean square roughness decreased from 80 to 26 nm) were obtained. This study is expected to open up new possibilities for the development of high performance $AgBi_2I_7$ perovskite solar cells for applications in Pb-free energy conversion devices.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.253-262
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• 1981

The AgI/ PV${\cdot}$THF membrane electrode could be used as an indicator electrode in the potentiometric titration of single halide and mixture halide solutions with the standard solution of silver nitrate. The errors in the stepwise titrations of mixture halide solutions were considerably large, but by addition of flocculating agent, such as $NaNO_3$ or $Ba(NO_3)_2$, in the sample solution, the errors were greatly reduced. Also, the effects of gelatin, filter paper and temperature on the titration errors were examined.