• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.5
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• pp.719-726
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• 1999

Multiconductor transmission line(MTL) equations are solved by FDTD method to examine the coupling between incident electromagnetic fields and multiconductor transmission lines. The measurement of induced voltages on UTP Category 5 and STP Category 5 cables which are used as LAN cables is carried out using a TEM cell where uniform and strong TEM fields can be established. The comparison between measured and simulated results shows good agreement. It is also found that grounding of shield foil at both terminations and small grounding resistance give good shielding effects for STP Category 5.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.8
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• pp.1407-1411
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• 2008

In material processing, a laser system with optimal laser parameters has been considered to be significant. Especially, the laser scribing technology is thought to be very important for fabricating DSSC(Dye sensitized solar eel!) modules with good quality. Moreover, the $TEM_{00}$ mode laser beam is the most dominant factor to decide the IPCE(Incident photon to current conversion efficiency) characteristics. In order to get the $TEM_{00}$ mode, a pin-hole is inserted within a simple pulsed Nd:YAG laser resonator. And the spatial field distribution is measured by using three size pin-hole diameters of 2.0, 6.0mm respectively. At that moment, each case has the same laser beam energy by adjusting the discharge voltage and pps(pulse per second). From those results, it is known that the pin-hole size of 2.0mm has the perfect $TEM_{00}$ mode. In addition, at the charging voltage of 1000V, 10pps and the feeding speed of 1.11mm/sec, the SEM photo of FTO(Fluorine-doped tin oxide) thin film layers shows the best scribing trace.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.1
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• pp.64-69
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• 2019

Methylammonium lead triiodide ($MAPbI_3$)-based perovskite solar cells potentially have potential advantages such as high efficiency and low-cost manufacturing procedures. However, $MAPbI_3$ is structurally unstable and has low phase-change temperatures ($30^{\circ}C$ and $130^{\circ}C$); it is necessary to solve these problems. We investigated the crystal structure and phase separation using real-time temperature-change X-ray diffraction, transmission electron microscopy, and electron energy loss spectroscopy. $MAPbI_3$ has a tetragonal structure, and at about $35^{\circ}C$ the c-axis contracts, transforming $MAPbI_3$ into the related cubic crystal structure. In addition, at $130^{\circ}C$, phase separation occurs in which $CH_3NH_2$ and HI at the center of the unit cell of the perovskite structure are extracted by gas, leavingand only $PbI_2$ of the three-component structure, is produced as the final solid product.

• Food Science and Preservation
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• v.3 no.2
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• pp.187-193
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• 1996

To investigate the antimicrobial activities and effect of grapefruit seed extract(GFSE) on the physiological function of microorganism, antimicrobial activity, fatty acids of bacterial cell lipid and amino acids of bacterial cell protein were measured. The change of cell morphotype was observed by transmission electron microscope. GFSE was very stable on the wide range temperture and pH. The growth rate of E. coli and B. suvtilis were decreased above 40ppm GFSE There fore, minimum inhibitory concentration (MIC) of the E. coli and B. subtilis to GFSE were determined around 40ppm. In the change of fatty acids quantities, hexadecanoate was significantly decreased on the treatment compared with control in case of E. coli, whereas tridecanoate was not detected in case of B. subtilis. In the change of amino acids quantities, alanine, glutamic acid, glycine, lysine were decreased on the treatment compared with control in case of E. coli and B. subtilis Transmission electron microsgraphs(TEM) showed the microbial cells were destroyed by GFSE.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.185-196
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• 1990

These experiments were performed to know ultrastructural changes of the cumulus expansion in virot. SEM:In expanded oocyte-cumulus complex, the cell surface are characterized by the presence of many evaginations:they are relatively short and round shape. The mucous extracellular material were deposited between cumulus cells. TEM:In compact cumulus cells, golgi apparatus and rough endoplasmic reticulum developed. In expanded cumulus cells, rough endoplasmic reticulum decreased and the smooth endoplasmic reticulum increased. Also, there were numbers of mitochondria. Extracellular mucous material which is presumed to be hyaluronic acid appears when cumulus cell were expanded. In expanded cumulus cell, numbers of smooth endoplasmic reticulum help cumulus cell to develop in steroidogenic cell.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5905-5910
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• 2013

Background: To investigate the preventive and therapeutic potential of garlic oil on human pancreatic carcinoma cells. Methods: The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay was performed to study the effects of garlic oil on three human pancreatic cancer cell lines, AsPC-1, Mia PaCa-2 and PANC-1. Cell cycle progression and apoptosis were detected by flow cytometry (FCM), staining with PI and annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI), respectively. Morphologic changes of pancreatic cancer cells were observed under transmission electron microscopy (TEM) after treatment with garlic oil at low inhibitory concentrations ($2.5{\mu}M$ and $10{\mu}M$) for 24 hours. Results: Proliferation of the AsPC-1, PANC-1, and Mia PaCa-2 cells was obviously inhibited in the first 24 hours with the MTT assay. The inhibition effect was more significant after 48 hours. When cells were exposed to garlic oil at higher concentrations, an early change of the apoptotic tendency was detected by FCM and TEM. Conclusion: Garlic oil could inhibit the proliferation of AsPC-1, PANC-1, and Mia PaCa-2 cells in this study. Moreover, due to programmed cell death, cell cycle arrest, or both, pro-apoptosis effects on AsPC-1 cells were induced by garlic oil in a dose and time dependent manner in vitro.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.522-526
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• 1999

Bactericidal effects of chitosans with varying molecular weight $(10,000{\sim}170,000)$ were investigated for Streptococcus mutans, a primary causative bacterium of dental caries. The molecular weight of chitosan was a significant contributor to the bactericidal effect, and a chitosan having approximately 30,000 of molecular weight exhibited the highest bactericidal effects on S. mutans. Treatment of chitosan resulted in leaking intracellular protein and nucleic acid out of S. mutans cells. In addition, the divalent cations such as $Ca^{2+}\;and\;Mg^{2+}$ were also significantly released out of the cell. Visible damage of chitosan treated cells was observed by transmission electron microscopy (TEM), in which the cell wall was notably distorted and cytoplasmic membrane was separated from the cell wall. The results suggested that the bactericidal effect of chitosan on S. mutans was attributable to both leakage of intracellular materials and structural disintegration of cell wall.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.283-292
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• 2005

This study investigated the effects of naringin, and chitosan in rabbits' corneas. Naringin, a glycone of naringenin, is a widely distributed bioflavonoid in the grapefruit and citrus peel, and it has already been reported as an antioxidant, antimicrobial, and anticancer agent. It has been used as a food preservatives and cosmetics. One of the natural preservatives, chitosan has also used in food preservatives, health drinks, and teas. Chitosan is distributed in the epithelium of crustacea, insects, and fungi. Naringin and chitosan have no harmful effects of cytotoxicity in the human body and they are recognized as an antibacterial for various forms of bacteria. The purpose of this study is to search for the ideal percentage of natural products to substitute the chemical preservatives occuring within the cornea and conjunctiva cytotoxicity and inflammations as wearing on soft contact lens. The present study compared the morphology of corneal epithelium and endothelium observed by light microscopy (LM) and transmission electron microscopy (TEM). In vivo methods, We investigated the effects of natural preservatives on soft contact lens. We inserted 3-4 drops of the naringin and chitosan, directly on rabbits' corneas 4 times per a day during one week. After enucleation of cornea, morphorgical damages of the epithelium and endothelium were observed by LM and TEM. In view of ultrastructure, chitosan caused siginficant damage on the epithelium and endothelium of cornea. The damage of cells was higher in chitosan treated cornea than 0.01, 0.1, and 1% of naringin. The 1% of naringin also expressed cell damage seriously. The results suggest that the most important thing is to use the reasonable percentage of preservatives for contact lens solutions.

• Korean Journal of Materials Research
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• v.10 no.7
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• pp.478-481
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• 2000

Single phase $Pb(Mg_{1/3}Nb_{2/3})O_3$ ceramics doped by 10 mol% of electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, were synthesized and their B-site cationic ordering structures were investigated by XRD and TEM. In the XRD patterns, only fundamental reflections were observed for the undoped $Pb(Mg_{1/3}Nb_{2/3})O_3$, while the (h/2 $\textsc{k}$/2ι/2)(h,$\textsc{k}$,ι all odd) superlattice reflections resulting from the 1:1 ordering induced unit cell doubling were also observed for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. In the TEM selected area diffraction patterns, the (h/2 k/2 l/2)(h,k,l all odd) superlattice reflection spots as well as the fundamental reflection spots were observed for all the samples, but the relative intensities of the superlattice reflection spots to the fundamental reflection spots were significantly enhanced by the donor-doping. In the TEM dark-field images, antiphase boundaries were observed only for the donor-doped $Pb(Mg_{1/3}Nb_{2/3})O_3$. It was therefore experimentally verified that doping by electron donors such as $La^3,\; Pr^{3+,4+},\; Nd^{3+},\; Sm^{3+}$, enhances the B-site cationic 1:1 ordering in $Pb(Mg_{1/3}Nb_{2/3})O_3$. These experimental results were interpreted in terms of the charge compensation mechanism.

• Journal of the Mineralogical Society of Korea
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• v.9 no.1
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• pp.26-34
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• 1996

The white leather-like playgorskite occurs as a vein in the Cretaceous sedimentary rocks in the Yeongsan area, Kyeongnam, Korea. It has been investigate by means of XRD, TEM, DTA-TG, IR and chemical analysis. The palygorskite vein is composed mostly of well-crystallized palygorskite. The wall rock of the vein is altered to smectite along both sides of the vein. According to TEM observation the palygorskite shows a fibrous habit. The sizes offibers are quite variable, ranging from 0.1 to 3.0 micron in length. From XRD data, the palygorskite has orthorhombic unit cell with a=12.726$\AA$, b=17.796$\AA$, c=5.1666$\AA$. The chemical formula of the palygorskite was calculated as [Si7.93Al0.07](Al1.91Fe+30.11Mg1.96)Ca0.01O20(OH)4(OH2)2.