• Journal of the Mineralogical Society of Korea
• /
• v.31 no.4
• /
• pp.235-248
• /
• 2018

The present work was performed in order to study the effect of competing cation of $Ca^{2+}$ ion on ion exchange of $Cs^+$ on zeolite Y (Si/Al = 1.56). Three single-crystals of fully dehydrated and partially $Cs^+$-exchanged zeolites Y (Si/Al = 1.56) were prepared by the flow method using mixed ion-exchange solutions. The $CsNO_3:Ca(NO_3)_2$ molar ratios of the ion exchange solution were 1 : 1 (crystal 1), 1 : 100 (crystal 2), and 1 : 250 (crystal 3) with a total concentration of 0.05 M. The single-crystals were then vacuum dehydrated at 723 K and $1{\times}10^{-4}Pa$ for 2 days. The structures of the crystals were determined by single-crystal synchrotron X-ray diffraction technique in the cubic space group $Fd{\bar{3}}m$, at 100(1) K. The unit-cell formulas of crystals 1, 2, and 3 were ${\mid}Cs_{21}Ca_{27}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, ${\mid}Cs_2Ca_{36.5}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, and ${\mid}Cs_1Ca_{37}{\mid}[Si_{117}Al_{75}O_{384}]-FAU$, respectively. In all three crystals, the $Ca^{2+}$ ions preferred to occupy site I in the D6Rs, with the remainder occupying sites I', II', and II. On the other hand, the significant differences in the fractional distribution of $Cs^+$ ions are observed depending on the intial $Cs^+$ concentrations in given ion exchange solution. In Crystal 1, $Cs^+$ ion are located at sites II', II, III, and III', and in crystal 2, at sites II, IIIa, and IIIb. In crystal 3, $Cs^+$ ions are only located at sites IIIa and IIIb. The degree of $Cs^+$ ion exchange decreased sharply from 28.0 to 2.7 to 1.3 % as the initial $Ca^{2+}$ concentration increases and the $Cs^+$ content decreases.

• Journal of Animal Science and Technology
• /
• v.45 no.3
• /
• pp.377-386
• /
• 2003

A study was conducted to evaluate seasonal variations in chemical composition of food waste (FW) and its feeding effects on growth performance and pork quality in finishing pigs. FW was collected for 1 year (6 times a month) to establish a database for use of FW as a feed ingredient. For a feeding trial (8 weeks), a total of 117 pigs ${\times}$D; 54.80$\pm$4.60kg) were used to evaluate the processing effects of FW. Treatments were: Control (a corn-soybean meal diet without FW), simple dried FW (SD) and vacuum fermented FW (VF). The gross energy, crude protein, crude fat, ash, calcium and phosphorus in FW (DM, average of 4 seasons) were 5,111kcal/kg, 22.92%, 14.31%, 15.48%, 2.7% and 1.05%, respectively. Among seasons, the energy and crude protein contents were the highest (p<0.05) in winter and summer, respectively. In lactic acid bacterial counts, there was no difference between SD and VF. Pigs fed the control diet grew faster (p<0.05) than those fed diets containing food wastes, but not feed conversion ratio. There were no differences in production traits between SD and VF. No differences were also found in dressing percentage, backfat thickness, and pork quality (color, drip loss and TBARS) among treatments. The feed cost (￦/kg body weight) was lower in pigs fed FW than those fed a control diet. In conclusion, a pelleted diet containing food waste less than 20% would reduce feed cost in finishing pigs. However, it seems that a vacuum fermentation of food waste is not necessary for diet processing.

• Journal of the Korean Chemical Society
• /
• v.40 no.7
• /
• pp.474-482
• /
• 1996

Two crystal structures of the vacuum dehydrated $Ag^+$-exchanged zeolite X have been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21(1)$^{\circ}C$ (a=24.922(1)${\AA}$ and a=24.901(1)${\AA}$, respectively). Each crystal was ion exchanged in flowing streams of aqueous $AgNO_3$ for three days. The first crystal was dehydrated at 300$^{\circ}C$ and $2{\times}10^{-6$torr for two days. The second crystal was similarly dehydrated at 350$^{\circ}C$. Their structures were refined to the final error indices, $R_1=0.095\;and\;R_2=0.092$ with 227 reflections, and $R_1=0.096\;and\;R_2=0.087$ with 334 reflections, respectively, for which I > 3${\sigma}$(I). In the first crystal, Ag species are found at five different crystallographic sites: sixteen $Ag^+$ ions fill the site I, the center of the double 6-ring, thirty-two Ag0 atoms fill the I' site in the sodalite cavities opposite double six-rings, seventeen $Ag^+$ ions lie at the 32-fold site II' inside the sodalite cavity at the single six-oxygen ring in the supercage, fifteen Ag+ ions lie at the 32-fold site II, in the supercage, and the remaining twelve $Ag^+$ ions lie at site III' in the supercage at a little off two-fold axes. In the second crystal, all Ag species are located similarly as crystal 1; 16 at site I, 28 at site I', 16 at site II, 16 at site II', 6 at site III and 6 at site III'. Total 88 silver species were found per unit cell. The remaining four Ag atoms were migrated out of the zeolite framework to form small silver crystallites on the surface of the zeolite single crystal. In the first structure, the numbers of Ag atoms per unit cell are approximately 32.0 and these may form tetrahedral $Ag_4$ clusters at the centers of the sodalite cavities. The probable four-atom cluster is stabilized by coordination to two $Ag^+$ ions. The Ag-Ag distance in the cluster, ca. 3.05 ${\AA}$, is a little longer than 2.89 ${\AA}$, Ag-Ag distance in silver metal. At least two six-ring $Ag^+$ ions on sodalite cavity (site II') must necessarily approach this cluster and this cluster may be viewed as a distorted octahedral silver cluster, (Ag6)2+.

• Korean Journal of Remote Sensing
• /
• v.37 no.5_2
• /
• pp.1245-1257
• /
• 2021

GOCI-II, succeeding the mission of GOCI, was launched in February 2020 and has been in regular operation since October 2020. Korea Institute of Ocean Science and Technology (KIOST) processes and produces in real time Level-1B and 26 Level-2 outputs, which then are provided by Korea Hydrographic and Oceanographic Agency (KHOA). We introduced current status of regular GOCI-II operation and showed future improvement. Basic GOCI-II products including chlorophyll-a, total suspended materials, and colored dissolved organic matter concentration, are induced by OC4 and YOC algorithms, which were described in detail. For the full disk (FD), imaging schedule was established considering solar zenith angle and sun glint during the in-orbital test, but improved by further considering satellite zenith angle. The number of slots satisfying the condition 'Best Ocean' significantly increased from 15 to 78. GOCI-II calibration requirements were presented based on that by European Space Agency (ESA) and candidate fixed locations for calibrating local observation area were. The quality management of FD uses research ships and overseas bases of KIOST, but it is necessary to establish an international calibration/validation network. These results are expected to enhance the understanding of users for output processing and help establish detailed plans for future quality management tasks.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.19 no.4
• /
• pp.427-435
• /
• 2008

In this paper, a stable marching-on in time(MOT) method with a time domain combined field integral equation(CFIE) is presented to obtain the transient scattering response from arbitrarily shaped three-dimensional conducting bodies. This formulation is based on a linear combination of the time domain electric field integral equation(EFIE) with the magnetic field integral equation(MFIE). The time derivatives in the EFIE and MFIE are approximated using a central finite difference scheme and other terms are averaged over time. This time domain CFIE approach produces results that are accurate and stable when solving for transient scattering responses from conducting objects. Numerical results with the proposed MOT scheme are presented and compared with those obtained from the conventional method and the inverse discrete Fourier transform(IDFT) of the frequency domain CFIE solution.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.273-273
• /
• 1996

Recently a novel in vivo approach in dogs, using a regional segmental intestinal perfusion technique, has been developed. The perfusion tube consists of a highly sophisticated multichannel tube with two inflatable occluding balloons, which are placed in 10cm apart. The tube was introduced orally from the stomach through the upper jejunum under the guidance of solid-state pH meter. In the present study, four healthy dogs were infused in the proximal jejunum on two periods. The two perfusion experiments used the same flow rate, 2 $m\ell$/min, and the same perfusion solution to determine the intrasubject variability. The mean (${\pm}$ S. E.) fractions of ranitidine absorbed calculated from the perfusion data were 21.32${\pm}$2.01% (n=3) (1st period), 27.88 ${\pm}$ 17.54% (n=4) (2nd period), respectively. The effective permeabilities (Peffs${\times}$10$\^$4/) of ranitidine were 1.51${\pm}$0.47cm/sec (n=3) (1st period), 1.50 ${\pm}$ 0.31 cm/sec (n=4) (2nd period), respectively. The pH and osmolarity of perfusion solution were 7.50 ${\pm}$ 0.03 and 300 ${\pm}$ 0.06 mOsm/L, There was no significant intrasubject variation. Mixing equilibrium (steady-state) was reached at about 50 min. l-Phenylalanine was absorbed almost completely. Intrinsic intestinal wall permeability of ranitidine showed low permeable characteristics, suggesting permeability-limited absorption. The absorption of 1-phenylalanine, an actively transported nutrient, was not inhibited by ranitidine. The low intestinal membrane permeability is one of the important factors responsible for the variable oral absorption of ranitidine. Supported by FDA Grant FD01462-04 and KOSEF Grant.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.07a
• /
• pp.455-458
• /
• 2001

Spinel $LiMn_{2-y}$$M_{y}$ $O_4$powder was prepared solid-state method by calcining the mixture of LiOH - $H_2O$, Mn $O_2$, ZnO and MgO at 80$0^{\circ}C$ for 36h. To investigate the effect of substitution with Mg, Zn cation, charge-discharge experiments and initial impedance spectroscopy performed. The structure of $LiMn_{2-y}$$M_{y}$ $O_4$crystallites was analyzed from powder X-ray diffraction data as a cubic spinel, space group Fd3m. all cathode material showed spinel phase based on cubic phase in X-ray diffraction. Ununiform which calculated by (111) face and (222) face was constant in spite of the change of y value, except PUf\ulcorner LiM $n_2$ $O_4$. The discharge capacities of the cathode for the cation subbstitUtes $LiMn_{2-y}$$M_{y}$ $O_4$/Li cell at the 1st cycle and at the 40th cycle were about 120~124 and 108~112mAh/g except LiM $n_{1.9}$Z $n_{0.1}$ $O_4$/Li cell, respectively. This cell capacity is retained by 93% after 40th cycle. AC impedance of $LiMn_{2-y}$$M_{y}$ $O_4$/Li cells revealed the similar resistance of about 65~110$\Omega$ before cycling. before cycling.g.g.

• Journal of the Korean Ceramic Society
• /
• v.40 no.7
• /
• pp.620-624
• /
• 2003

LiCo$_{y}$Mn$_{2-y}$O$_4$ samples were synthesized by calcining a mixture of LiOH.$H_2O$, MnO$_2$ (CMD) and CoCO$_3$ calcining at 40$0^{\circ}C$ for 10 h and then calcining twice at 75$0^{\circ}C$ for 24 h in air with intermediate grinding. All the synthesized samples exhibited XRD patterns for the cubic spinel phase with a space group Fd(equation omitted)m. The electrochemical cells were charged and discharged for 30 cycles at a current density 600 $mutextrm{A}$/$\textrm{cm}^2$ between 3.5 and 4.3 V. As the value of y increases, the size of particles becomes more homogeneous. The first discharge capacity decreases as the value of y increases, its value for y=0.00 being 92.8 mAh/g. The LiMn$_2$O$_4$ exhibits much better cycling performance than that reported earlier. The cycling performance increases as the value of y increases. The efficiency of discharge capacity is 98.9％ for y=0.30. The larger lattice parameter for the smaller value of y is related to the larger discharge capacity. The more quantity of the intercalated and the deintercalated Li in the sample with the larger discharge capacity brings about the larger capacity fading rate.ate.

• Analytical Science and Technology
• /
• v.18 no.4
• /
• pp.278-286
• /
• 2005

The crystal structure of ($Tl_{71}$-Y ($Tl_{71}Si_{121}Al_{71}O_{384}$), ${\alpha}=24.706(3){\AA}$, dehydrated at 653 K and $8{\times}10^{-6}$ torr, has been determined by single-crystal X-ray diffraction techniques in the cubic space group $Fd\bar{3}m$ at 294(1) K. The structure was refined using all intensities to the final error indices (using only the 302 reflection for which $F_{\circ}$ > $4{\sigma}(F_0)$) $R_1=0.0602$ (based on F) and $R_w=0.1744$ (based on $F_2$). The 71 $Tl^+$ ions per unit cell are found at four crystallographically distinct positions. Site I' position in the sodalite cavity opposite D6Rs are each occupied by eighteen $Tl^+$ ions per unit cell; these $Tl^+$ ions are recessed ca. $1.45{\AA}$ into the sodalite cavity from their O(3) plane (Tl-O=2.701(15), $3.163(16){\AA}$ and O-Tl-O=$92.1(4)^{\circ}$). The 23 $T1^+$ ions fill site II in the supercage; these $T1^+$ ions are recessed ca. $1.58{\AA}$ into the supercage from their O(2) plane (Tl-O = 2.850(16), $3.156(16){\AA}$ and O-T1-O = $85.1(5)^{\circ}$). The 19 $Tl^+$ ions lie at site III' in the supercage near a triple 4-ring (Tl-O = 3.10(7), $3.39(5){\AA}$ and O-Tl-O = 47.8(9), $95.3(18)^{\circ}$) and the remaining II ions occupy another site III' near a triple 4-ring in the supercage (Tl-O = 2.81(4), $2.71(4){\AA}$ and O-Tl-O = $57.3(8)^{\circ}$).

• Archives of Pharmacal Research
• /
• v.28 no.10
• /
• pp.1170-1176
• /
• 2005

2-Methyl-2-(2-methylpropenyl)-2,3-dihydronaphthoquinone[2,3-b]furan-4,9-dione (N FD-37) is a synthetic furonaphthoquinone compound. In this study, we determined that NFD-37 could inhibit the lipopolysaccharide (LPS)-induced production of inflammatory mediators in macrophages RAW 264.7. This compound inhibited LPS-induced nitric oxide (NO) or prostaglandin (PG) $E_{2}$ production in dose-dependent manners, with $IC_{50}$ values of 7.2 ${\mu}M$ and 5.3 ${\mu}m$, respectively. As the positive controls, pyrrolidine dithiocarbamate (30 ${\mu}M$) exhibited a $57{\%}$ inhibition of NO production, and NS-398 ($1{\mu}M$) manifested a $48{\%}$ inhibition of $PGE_2$ production. The inhibitory effects of NFD-37 on NO and $PGE_2$ production were determined to occur in conjunction with the suppression of inducible NO synthase or cyclooxygenase-2 expression. NFD-37 also inhibited the production of LPS-inducible tumor necrosis factor-${\alpha}$, interleukin (IL)-$1{\beta}$ and IL-6, at $IC_{50}$ values of 4.8-8.9 ${\mu}M$. We also determined the anti-inflammatory efficacy of NFD-37 using carrageenin-induced paw edema in experimental mice.