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

• Polymer(Korea)
• /
• v.33 no.4
• /
• pp.358-363
• /
• 2009

Maleic anhydride-grafted polypropylene has been widely used to improve the interfacial interaction between the components in PP/polar polymer blends and PP/filler composites and to maximize the physical properties and thermal properties. In this paper. the maleic anhydride (MAH)-grafted polypropylene (co-PP) was fabricated through reactive extrusion process with di-cumyl peroxide (DCP) as an initiator. The grafting degree of MAH depending on the contents of DCP and MAH was investigated by FT-IR spectra and chemical titration. The grafting degree increased with increasing MAH concentration and also showed maximum value at 0.06 wt% of DCP concentration. Melt flow index (MFI) of the grafted copolymer was increased with increasing the contents of MAH. The DSC and TGA analysis data indicate the melting temperature and thermal degradation of PP depending on the grafting degree of MAH.

• Molecules and Cells
• /
• v.39 no.6
• /
• pp.468-476
• /
• 2016

PLZF-expressing invariant natural killer T cells and CD4 T cells are unique subsets of innate T cells. Both are selected via thymocyte-thymocyte interaction, and they contribute to the generation of activated/memory-like CD4 and CD8 T cells in the thymus via the production of IL-4. Here, we investigated whether $PLZF^+$ innate T cells also affect the development and function of $Foxp3^+$ regulatory CD4 T cells. Flow cytometry analysis of the thymus and spleen from both CIITA transgenic C57BL/6 and wild-type BALB/c mice, which have abundant $PLZF^+$ CD4 T cells and invariant natural killer T cells, respectively, revealed that $Foxp3^+$ T cells in these mice exhibited a $CD103^+$ activated/memorylike phenotype. The frequency of $CD103^+$ regulatory T cells was considerably decreased in $PLZF^+$ cell-deficient $CIITA^{Tg}Plzf^{lu/lu}$ and $BALB/c.CD1d^{-/-}$ mice as well as in an IL-4-deficient background, such as in $CIITA^{Tg}IL-4^{-/-}$ and $BALB/c.IL-4^{-/-}$ mice, indicating that the acquisition of an activated/ memory-like phenotype was dependent on $PLZF^+$ innate T cells and IL-4. Using fetal thymic organ culture, we further demonstrated that IL-4 in concert with TGF-${\beta}$ enhanced the acquisition of the activated/memory-like phenotype of regulatory T cells. In functional aspects, the activated/ memory-like phenotype of Treg cells was directly related to their suppressive function; regulatory T cells of $CIITA^{Tg}PIV^{-/-}$ mice more efficiently suppressed ovalbumin-induced allergic airway inflammation compared with their counterparts from wild-type mice. All of these findings suggest that $PLZF^+$ innate T cells also augmented the generation of activated/memory-like regulation via IL-4 production.

• The Journal of Engineering Geology
• /
• v.13 no.4
• /
• pp.457-474
• /
• 2003

This study aims to elucidate characteristics of groundwater level fluctuation at riverbank filtration sites in Daesan-myeon, Changwon City. Groundwater level fluctuation, river water level change and stream-aquifer interaction are very important to estimate optimal discharge rate of the pumping well. Water level contours from February 2003 to October 2003 show normal decreasing trend toward the Nakdong river with the hydraulic gradient of 0.008. However, flow reversion occurs when groundwater is discharged at the pumping wells or rise of the Nakdong river by rainfall. The fluctuation of the Nakdong river ranges 0 - 10 m msl. Autocorrelation analysis was conducted to the groundwater levels measured on the six monitoring wells (DS1, DS2, DS3, DS4, DS6 and DS7). The analyzed waterlevel data can be grouped into three: group 1 (DS1 and DS3) represents strong linearity and long memory effect, group 2 (DS1 and DS6) intermediate linearity and memory, and group 3 (DS4 and DS7) weak linearity and memory. Waterlevels of group 1 wells are relatively closely related to the change of river-water level. Those of group 2 wells are largely affected by the pumping and the river-water level, and those of group 3 wells are strongly linked to pumping.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.29 no.2
• /
• pp.92-108
• /
• 2017

Present work shows a numerical method to analysis of interaction analysis between solitary wave and onshore bridge. Numerical simulation is carried out by TWOPM-3D (three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. To do this, the solitary wave is generated numerically in numerical wave channel, and numerical results and experimental results were compared and analyzed in order to verify the applicability of force acting on an onshore bridge. From this, we discussed precisely the characteristics of horizontal and vertical forces (uplift and downward forces) changes including water level and velocity changes due to the variation of solitary wave height, water depth, onshore bridge's location and type, and number of girder. Furthermore, It is revealed that the maximum horizontal and vertical forces acting on the girder bridge show different varying properties according to the number of girder, although each maximum force acting on the girder bridge is proportional to the increasement of incident solitary wave height, and the entrained air in the fluid flow affects the vertical force highly.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.32 no.1
• /
• pp.55-68
• /
• 2020

In order to investigate the hydraulic characteristics of a boundary layer streaming over the beach cusps appeared in swells prevailing mild seas, we numerically simulated the shoaling process of Edge waves over the beach cusp. Synchronous Edge waves known to sustain the beach cusps could successfully be duplicated by generating two obliquely colliding Edge waves in front of beach cusps. The amplitude A_B and length L_B of Beach Cusp were elected to be 1.25 m and 18 m, respectively based on the measured data along the Mang-Bang beach. Numerical results show that boundary layer streaming was formed at every phase of shoaling process without exception, and the maximum boundary layer streaming was observed to occur at the crest of sand bar. In RUN 1 where the shortest waves were deployed, the maximum boundary layer streaming was observed to be around 0.32 m/s, which far exceeds the amplitude of free stream by two times. It is also noted that the maximum boundary layer streaming mentioned above greatly differs from the analytical solution by Longuet-Higgins (1957) based on wave Reynolds stress. In doing so, we also identify the recovery procedure of natural beaches in swells prevailing mild seas, which can be summarized such as: as the infra-gravity waves formed in swells by the resonance wave-wave interaction arrives near the breaking line, the sediments ascending near the free surface by the Phase II waves orbital motion were carried toward the pinnacle of foreshore by the shoreward flow commenced at the steep front of breaking waves, and were deposited near the pinnacle of foreshore due to the infiltration.

• Journal of the Institute of Convergence Signal Processing
• /
• v.10 no.4
• /
• pp.274-279
• /
• 2009

The flow of a universal system-level design methodology consists of system specification, system-level hardware/software partitioning, co-design, co-verification using virtual or physical prototype, and system integration. In this paper, verification environments based-on SystemVerilog and SystemC, one is native-code co-verification environment which makes prompt functional verification possible and another is SystemVerilog layered testbench which makes clock-level verification possible, are implemented. In native-code co-verification, HW and SW parts of SoC are respectively designed with SystemVerilog and SystemC after HW/SW partitioning using SystemC, then the functional interaction between HW and SW parts is carried out as one simulation process. SystemVerilog layered testbench is a verification environment including corner case test of DUT through the randomly generated test-vector. We adopt SystemC to design a component of verification environment which has multiple inheritance, and we combine SystemC design unit with the SystemVerilog layered testbench using SystemVerilog DPI and ModelSim macro. As multiple inheritance is useful for creating class types that combine the properties of two or more class types, the design of verification environment adopting SystemC in this paper can increase the code reusability.

• Journal of Soil and Groundwater Environment
• /
• v.19 no.2
• /
• pp.7-15
• /
• 2014

This study was conducted to understand the chemical characteristics of groundwater in carbonate areas of Korea. In this study, data on pH, electric conductivity (EC), $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ were collected from 97 wells which were installed in various carbonate rock regions of Korea. The pH values ranged from 5.7 to 9.9, and the average value was 7.3. The concentration range showed differences between the maximum value of $HCO_3{^-}$ and the medium to minimum values of $Ca^{2+}$, $Mg^{2+}$, $Na^+$, $Cl^-$, $SO_4{^{2-}}$, and $K^+$ in the study area. The average value of EC was $374{\mu}S/cm$, higher than in granite and gneiss areas, where the value is $176{\mu}S/cm$. Most of the groundwater was type $Ca-HCO_3$, and some was type $Mg-HCO_3$. The relationship between $Ca^{2+}$, $Cl^-$, and $HCO_3{^-}$, respectively, and EC showed relatively significant positive correlations compared to the other dissolved components. However, the determination coefficients for $Mg^{2+}$, $Na^+$, $SO_4{^{2-}}$, and $K^+$ were very low less than 0.2. These results indicate that the source of $Ca^{2+}$ and $Mg^{2+}$ is relatively simple (carbonate dissolution) compared to other sources. The sources of $Na^+$, $K^+$, $Cl^-$, $SO_4{^{2-}}$, and $HCO_3{^-}$ might be not only water-rock interactions, but also irrigation return flow, because many groundwater wells had been developed for irrigation purposes. Subsequently, the influence of agriculture on groundwater chemistry was evaluated using a cumulative plot of $SO_4{^{2-}}$. The threshold value of $SO_4{^{2-}}$ calculated from the cumulative frequency curve was 29.2 mg/L. Therefore, 12.4% of all the groundwater wells were affected by agricultural activity.

• Membrane Journal
• /
• v.12 no.1
• /
• pp.41-50
• /
• 2002

The streaming potential generated by the electrokinetic flow within electric double layer of charged microchannel is applied to determine the zeta potential of hollow-fiber membrane pore by using the general Helmholtz-Smoluchowski equation. The streaming potential is know to provide a useful real-time information on the surface property and the interaction between pore and particles in actual situations and physicochemical conditions. The influence of physicochemical parameters upon the filtration with hollow-fibers has been examined with an in-situ and simultaneously monitoring the streaming potential as well as permeate flux. In particular, the present study examined an experimental method to identify the effect of cake layer which can vary according to the axial position of a hollow-fiber and the progress of membrane fouling by measuring the position-dependent streaming potential. As the latex concentration increases, the permeate flux decreased but the streaming potential increased. The growth of cake layer has been mire developed with increasing latex concentration, however, the effect of surface charges of latexes deposited on the membrane surface leads to increase the streaming potential. With increasing ionic concentration of KCI, both the permeate flux and the streaming potential decrease. The increase of ionic concentration provides a compact cake layer due to the shrinkage of Debye length and the decreased streaming potential results from the weakened ionic flows owing to a thin diffusive double layer.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.44-45
• /
• 2010

We are currently conducting studies on culturing and biocompatibility assessment of various cells such as neural stem cells and induced pluripotent stem cells(IPS cells) on carbon nanotube (CNT), on nerve regeneration electrodes, and on silicon wafers with a focus on developing nerve integrated CNT based bio devices for interfacing with living organisms, in order to develop brain-machine interfaces (BMI). In addition, we are carried out the chemical modification of carbon nanotube (mainly SWCNTs)-based bio-nanosensors by the plasma ion irradiation (plasma activation) method, and provide a characteristic evaluation of a bio-nanosensor using bovine serum albumin (BSA)/anti-BSA binding and oligonucleotide hybridization. On the other hand, the researches in the case of "novel plasma" have been widely conducted in the fields of chemistry, solid physics, and nanomaterial science. From the above-mentioned background, we are conducting basic experiments on direct irradiation of body tissues and cells using a micro-spot atmospheric pressure plasma source. The device is a coaxial structure having a tungsten wire installed inside a glass capillary, and a grounded ring electrode wrapped on the outside. The conditions of plasma generation are as follows: applied voltage: 5-9 kV, frequency: 1-3 kHz, helium (He) gas flow: 1-1.5 L/min, and plasma irradiation time: 1-300 sec. The experiment was conducted by preparing a culture medium containing mouse fibroblasts (NIH3T3) on a culture dish. A culture dish irradiated with plasma was introduced into a $CO_2$-incubator. The small animals used in the experiment involving plasma irradiation into living tissue were rat, rabbit, and pick and are deeply anesthetized with the gas anesthesia. According to the dependency of cell numbers against the plasma irradiation time, when only He gas was flowed, the growth of cells was inhibited as the floatation of cells caused by gas agitation inside the culture was promoted. On the other hand, there was no floatation of cells and healthy growth was observed when plasma was irradiated. Furthermore, in an experiment testing the effects of plasma irradiation on rats that were artificially given burn wounds, no evidence of electric shock injuries was found in the irradiated areas. In fact, the observed evidence of healing and improvements of the burn wounds suggested the presence of healing effects due to the growth factors in the tissues. Therefore, it appears that the interaction due to ion/radicalcollisions causes a substantial effect on the proliferation of growth factors such as epidermal growth factor (EGF), nerve growth factor (NGF), and transforming growth factor (TGF) that are present in the cells.