• Applied Microscopy
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• v.38 no.3
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• pp.275-278
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• 2008

Electron tomography (ET) is an electron microscopic technique for obtaining a 3-D image from any electron microscopy specimen and its application in biomedical science has been increased thanks to development of electron microscopy and related technologies during the last decade. There are few researches on ET in Korea during this period. Although the importance of ET has been recognized recently by many researchers, initial approach to electron tomographic research is not easy for beginners. The 4th International Congress on Electron Tomography (4 ICET) was held on Nov $5{\sim}8$, 2006, at San Diego. The program dealt instrumentation, reconstruction algorithm, visualization/quantitative analysis and electron tomographic presentation of biological specimen and nano particles. 1 have summarized oral presentations and analyzed the posters presented on the meeting. Cryo-electron microscopic system was popular system for ET and followed conventional transmission electron microscopic system. Cultured cell line and tissue were most popular specimens analyzed and microorganisms including bacteria and virus also constituted important specimens. This analysis provides a current state of art in ET research and a guide line for practical application of ET and further research strategies.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.335-340
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• 2018

To investigate the difference in the disinfectant efficiency of ozone microbubbles ($O_3MB$) and ozone millibubbles ($O_3MMB$), the morphological change of the treated Fusarium oxysporum f. sp. melonis spores was observed with scanning and transmission electron microscopies (SEM and TEM). The disinfectant efficiency of $O_3MB$ on F. oxysporum f. sp. melonis spores was greater than that of $O_3MMB$. On observation with SEM, it was revealed that morphological change of F. oxysporum f. sp. melonis spores was caused by $O_3MB$ and $O_3MMB$, and damage to the spore surfaces by $O_3MB$ occurred sooner than that by $O_3MMB$. On observation with TEM, it was furthermore confirmed that F. oxysporum f. sp. melonis spores treated with $O_3MB$ induced wavy deformation of cell membrane and the intracellular change different from that with $O_3MMB$. Therefore, the greater disinfection efficiency of $O_3MB$ was suggested to be caused due to the function of the MB in addition to the oxidative power of $O_3$.

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.258-263
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• 1998

Quasi-elastic light scattering is utilized to measure the mean diameter of the 0.3 $\mu\textrm{m}$-dimeter polystyrene sphere. The mean diameter of the polystyrene sphere is required to be known within the uncertainty of a few per centages. The systematic error has been considerably reduced by improving the system for the angle alignment and temperature measurement of cell. NIST SRM 1691 (0.269$\pm$0.007 $\mu\textrm{m}$: TEM; 0.275$\pm$0.007 $\mu\textrm{m}$: QELS) is measured to be 0.273 $\mu\textrm{m}$$\pm$0.006 $\mu\textrm{m}$ in mean diameter. Detailed description is given of the improved method and the resultant uncertainty, and the comparison of results with NIST is followed.

• Korean Journal of Materials Research
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• v.8 no.12
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• pp.1133-1137
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• 1998

By the mechanical alloying method Ni-W(WC) composite materials were prepared to improve the resistance for creep and sintering of Ni-anode at the operating temperature of$ 650^{\circ}C$. Amorphization was observed from the XRD analysis of mechanically alloyed powder caused by the destruction of ordered crystals. Sintering was performed at $1280^{\circ}C$ for 10 hours in $H_2$ atmosphere. From the result of dot-mapping and TEM analysis the second phase was not observed at Ni-W interface while W particles of less 0.lam were distributed finely and uniformly in Ni matrix. This finely and uniformly distributed W in Ni matrix is expected to enhance the mechanical properties of Ni-anode through the dispersion and solid solution hardening mechanisms.

• Food Science and Preservation
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• v.10 no.4
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• pp.565-568
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• 2003

The antibacterial activity for S. mutans by using 5 kinds of vinegar was researched. As a result it was the highest at persimmon vinegar and then grape, apple, high calcium brown rice, brown rice vinegar in order. The antibacterial effect was shown at 1.5% of persimmon vinegar concentration and the growth was fully repressed at 4% of concentration. As an observation result with a transmission electron microscope(TEM), the growth was obstructed by destroying the cell wall and the cytoplasmic membrane. As a research result of the total phenol contents for each vinegar, the persimmon vinegar was the highest as 237.49 mg% and the antibacterial activity was increased when the total phenol contents were high.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.715-722
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• 2022

Pt-Fe/carbon black nanocatalysts were prepared by spontaneous reduction reaction of Platinum(II) acetylacetonate and Iron(II) acetylacetonate in a nucleophilic solvent and they were characterized by scanning electron microscopy (SEM), energy dispersive X-ray analyzer (EDS), thermogravimetric analyzer (TGA), transmission electron microscopy (TEM), Brunauer, Emmett and Teller (BET) surface area analysis and anion exchange membrane (AEM) water electrolysis test station. The distribution of the Pt and Fe nanoparticles on carbon black was observed by TEM, and the loading weight of Pt-Fe nanocatalysts on the carbon black was measured by TGA. Elemental ratio of Fe:Pt was estimated by EDS and it was found that elemental ratio of Pt and Fe was changed in the range of 1:0 to 0:1, and the loading weight of Pt-Fe nanoparticles on the carbon black was 5.95-6.78 wt%. Specific surface area was greatly reduced because Pt-Fe nanocatalysts blocked the pores. I-V characteristics were estimated.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.74-82
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• 2015

As the complexity of an electronic device and the reduction of its operating voltage is progressing, susceptibility test of the chip and module for internal or external noises is essential. Although the immunity compliance of the chip was served with IEC 62132-4 Direct Power Injection method as an industry standard, in fact, EM immunity of the chip is influenced by their Power Domain Network (PDN). This paper evaluates the EM noise tolerance of a PLL and compares their noise transfer characteristics to the PLL on various PCB boards. To make differences of the PDNs of PCBs, various PCBs with or without LDO and with several types of capacitors are tested. For evaluation of discrepancies between EM characteristics of an IC only and the IC on real boards, the analysis of the noise transfer characteristics according to the PDNs shows that it gives important information for the design having robust EM characteristics. DPI measurement results show that greatly improved immunity of the PLL in the low-frequency region according to using the LDO and a frequency change of the PLL according to the DPI could also check with TEM cell measurement spectrum.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.1
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• pp.6-10
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• 2015

Photodynamic therapy (PDT) apply photosensitizers and light. The purpose of this study was to evaluate the in vitro efficacy of PDT using blue LED (light emitting diode) with photofrin and radachlorin for Propionibacterium acnes. The colony forming units method was used to assess the antibacterial activity. Suspension (1 mL) containing P. acnes at $1{\times}10^5CFU/mL$ were prepared and then 2 fold serial diluted to $12.5{\mu}g/mL$ from $50{\mu}g/mL$ concentration of photofrin and radachlorin. After 60 minutes incubation, light was irradiated for 10 to 30 minutes using the following light source of wavelength 460 nm, each energy density 36, 72 and $108J/cm^2$. Bacterial growth was evaluated after 72 hours incubation in a Phenylethanol Blood Agar (PEBA) culture. In addition, flow cytometric analysis were performed to measure the live cell after PDT. Also transmission electron microscopy (TEM) was employed to evaluate the effect of pathogens by PDT. The PDT Group was perfectly killed to all kind of photosensitizers dose of $12.5{\mu}g/mL$ with irradiation of 10 minutes. Also other Groups were killed to all kind of photosensitizers dose of $6.25{\mu}g/mL$ with irradiation time of 20 and 30 minutes. The flow cytometry showed a lower number of viable bacteria in the PDT group compared to the control group. The images of the TEM results were showed in cytoplasmic membrane damage and partially deformed to cell morphologies. These results suggest that radachlorin and photofrin combine blue LED PDT can be effectively treated when was proved treatment for acnes therapy.

• Korean Journal of Materials Research
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• v.27 no.2
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• pp.94-99
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• 2017

Dinickel-silicide $(Ni_2Si)/glass$ was employed as a counter electrode for a dye-sensitized solar cell (DSSC) device. $Ni_2Si$ was formed by rapid thermal annealing (RTA) at $700^{\circ}C$ for 15 seconds of a 50 nm-Ni/50 nm-Si/glass structure. For comparison, $Ni_2Si$ on quartz was also prepared through conventional electric furnace annealing (CEA) at $800^{\circ}C$ for 30 minutes. XRD, XPS, and EDS line scanning of TEM were used to confirm the formation of $Ni_2Si$. TEM and CV were employed to confirm the microstructure and catalytic activity. Photovoltaic properties were examined using a solar simulator and potentiostat. XRD, XPS, and EDS line scanning results showed that both CEA and RTA successfully led to tne formation of nano $thick-Ni_2Si$ phase. The catalytic activity of $CEA-Ni_2Si$ and $RTA-Ni_2Si$ with respect to Pt were 68 % and 56 %. Energy conversion efficiencies (ECEs) of DSSCs with $CEA-Ni_2Si$ and $RTA-Ni_2Si$catalysts were 3.66 % and 3.16 %, respectively. Our results imply that nano-thick $Ni_2Si$ may be used to replace Pt as a reduction catalytic layer for a DSSCs. Moreover, we show that nano-thick $Ni_2Si$ can be made available on a low-cost glass substrate via the RTA process.

• Applied Microscopy
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• v.29 no.3
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• pp.281-289
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• 1999

The stirred and thixoformed $SiC_p/AZ91HP$ Mg composites are studied on the basis of microstructural analysis using transmission electron microscopy (TEM). The products of interfacial reaction are identified as $Mg_2Si$, MgO and $Mg_{17}Al_{12}$ phases and the crystallized phases are found to be orthorhmbic $Al_6Mn$ and decagonal T phases. It is shown that $Mg_2Si$ and $Mg_{17}Al_{12}$ phases are found at the surface of $SiC_p$ and $Al_6Mn$ is found near interface and crystallized on the matrix. Phase identification is carried out by crystallographic work based on primitive cell volume, zero order Laue zone (ZOLZ) patterns and single convergent beam electron diffraction (CBED) patterns containing higher order Laue zone ring from a nanosized region.