• Food Science and Preservation
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• v.14 no.1
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• pp.1-7
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• 2007

This study was conducted to determine if chlorine dioxide ($ClO_{2}$) gas might minimize microbial contamination of fresh produce. After exposing grapes to 20 ppm or 40 ppm of chlorine dioxide gas in a closed container, grapes treated with 20 ppm $ClO_{2}$ were packaged in Ny/PE/L-LDPE pouches, stapes treated with 40 ppm $ClO_{2}$ were placed in an empty corrugated box, and untreated control grapes were placed in a box with a sachet containing $ClO_{2}$ gas adsorbed to silica gel (a silica gel pad). The free volume of the sachet material allowed the release of $ClO_{2}$ gas into the headspace of packages containing fresh grapes. Control fruit not exposed to $ClO_{2}$, was placed in a box and stored at either $25^{\circ}C$ or $0^{\circ}C$. Fruit in Ny/PE/L-LDPE film treated with 20 ppm $ClO_{2}$ lost almost no weight during storage at either $25^{\circ}C$ or $0^{\circ}C$. Such fruit had a lower soluble solid content than did other fruit samples. Titratable acidity tended to fall rapidly during storage at either $25^{\circ}C$ or $0^{\circ}C$. Anthocyanin content of grapes decreased over 21 days at $25^{\circ}C$ but increased over 10 weeks at $0^{\circ}C$. The total microbial count of grapes treated with $ClO_{2}$ gas and silica gel pads were lower than controls at $25^{\circ}C$. Fruit treated with 20 ppm $ClO_{2}$ and packaged in Ny/PE/L-LDPE pouches had lower microbial counts than other fruit samples when stored at $0^{\circ}C$. The silica gel pad did not significantly improve total microbial count (compared to untreated control samples) at $0^{\circ}C$. This result may be attributed to a higher rate of diffusion of $ClO_{2}$ gas at room temperature.

• Tribology and Lubricants
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• v.23 no.6
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• pp.298-300
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• 2007

Frictional characteristics of mesoporous $SiO_2$ thin films were evaluated with different pore sizes. The films were manufactured by sol-gel and self-assembly methods to have a porous structure. The pores on the surface may play as the outlet of wear particle and the storage of lubricant so that the surface interactions could be improved. The pores were exposed on the surface by chemical mechanical polishing (CMP) or plasma-etching after forming the porous films. The ball-on-disk tests with mesoporous $SiO_2$ thin films on glass specimen were conducted at sliding speed of 15 rpm and a load of 0.26 N. The results show considerable dependency of friction on pore size of mesoporous $SiO_2$ thin films. The friction coefficient decreased as increasing the pore size. CMP process was very useful to expose the pores on the surface.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.338-341
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• 2011

Thin silicon ribbon was used for fabricating flexible silicon p-i-n junction devices, consisting of 100${\times}$100 arrays of pixels in 1 inch on the diagonal. Those passive matrix devices exhibited the rectification ratio $>10^{4}$ owing to smaller cross-talking current than that of p-n junction devices. P-i-n devices fabricated on silica/silicon substrates are easily detached by treatment with hydrofluoric acid and are subsequently transferred onto both PDMS and flexible PET film.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.237-242
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• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.597-597
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• 2013

The resistive switching behaviors of Pt nanodisk on Nb-doped SrTiO3 single-crystal have been studied with conductive atomic force microscopy in ultra-high vacuum. The nanometer sizes of Pt disks were formed by using self-assembled patterns of silica nanospheres on Nb-doped SrTiO3 single-crystal semiconductor film using the Langmuir-Blodgett, followed by the metal deposition with e-beam evaporation. The conductance images shows the spatial mapping of the current flowing from the TiN coated AFM probe to Pt nanodisk surface on Nb：STO single-crystal substrate, that was simultaneously obtained with topography. The bipolar resistive switching behaviors of Pt nanodisk on Nb：STO single-crystal junctions was observed. By measuring the current-voltage spectroscopy after the forming process, we found that switching behavior depends on the charging and discharging of interface trap state that exhibit the high resistive state (HRS) and low resistive state (LRS), respectively. The results suggest that the bipolar resistive switching of Pt/Nb:STO single-crystal junctions can be performed without the electrochemical redox reaction between tip and sample with the potential application of nanometer scale resistive switching devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1030-1035
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• 2001

Strontium barium niobate, (Sr$\sub$0.5/Ba$\sub$0.5/Nb$_2$O$\sub$6/), thin films of various composition were prepared by the sol-gel method. Solution derived from acetate powders and niobium ethoxide in a mixture of acetic acid, ethylene glycol and 2-methoxyehanol was spin-coated onto bare silicon, Pt-coated silicon and fused silica substrates. Processing parameters were optimized to develop stable solutions which yielded films with relatively low crystallization temperatures. It was determined that ethylene glycol was a necessary component of the solution to increase stability against precipitation and to decrease the crystallization temperature of the films as confirmed by XRD and FT-IR analyses.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.1-4
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• 2003

The purpose of this study was to investigate the characteristics of slurry including phosphoric acid for chemical-mechanical planarization of copper and tantalum nitride. In general, the slurry for copper CMP consists of alumina or colloidal silica as an abrasive, organic acid as a complexing agent, an oxidizing agent, a film forming agent, a pH control agent and additives. Hydrogen peroxide (H$_2$O$_2$) is the material that is used as an oxidizing agent in copper CMP. But, the hydrogen peroxide needs some stabilizers to prevent decomposition. We evaluated phosphoric acid (H$_3$PO$_4$) as a stabilizer of the hydrogen peroxide as well as an accelerator of the tantalum nitride CMP process. We also estimated dispersion stability and zeta potential of the abrasive with the contents of phosphoric acid. An acceleration of the tantalum nitride CMP was verified through the electrochemical test. This approach may be useful for the development of the 2$\^$nd/ step copper CMP slurry and hydrogen peroxide stability.

• Applied Chemistry for Engineering
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• v.4 no.2
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• pp.240-253
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• 1993

Silicon alkoxides are used as a raw materials of silica fibers, coating films and fine ceramics. Specially, the alkoxides have been confirmed the best raw material for VLSI thin film of computors in recent years. Because, the impotance of silicon alkoxides are increasing more and more now a days. And so, in thls report the synthetic methods, reaction mechanism, application fields of silicon alkoxides are summerized. Also, the results of our research and technical problems of silicon alkoxide preparation are introduced briefly.

• Korean Journal of Food Science and Technology
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• v.1 no.1
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• pp.78-84
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• 1969

An attempt has been made to investigate the possible occurrence of aflatoxins, a group of micotoxin which are toxic metabolites produced by Aspergillus flavus, and aflatoxin like substances in fungal fermented soybean products such as meju and soybean paste. Chloroform extracts from 15 samples which has been defated with petroleum ether are subjected to separations with thin-layer chromatography on silica gel washed with methanol prior to film coating, improves the chromatographic separation and ultraviolet absorption spectral identification. In addition to fluorescencing spot having an Rf value which is same as aflatoxin $B_1$, many of the fluorescencing spots have been occurred in every sample examined. Each fluorescencing spot is scratched and the ethanol extracts are subjected to further separation with thin-layer chromatography. Each fluorescence substance is eluted with ultra violet transparent absolute ethanol and the ultraviolet absorption spectra are checked. None of the absorption curve of eluates shsow accordance with the curve of aflatoxin. 2, 4-Dinitrophenyl hydrazine reagent, Tollen's reagent and ninhydrin reagent are applied on the chromatogram- The data show that aflatoxin is not present in any of the fungal preparations examined.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.69-74
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• 2015

Cadmium telluride (CdTe) is being developed for thin film of the X-Ray detector recently. But a rough surface of the CdTe should be improved for resolution and signal speed. This paper shows the study on the improvement of surface roughness and removal rate by applying Chemical Mechanical Polishing. The conventional potassium hydroxide (KOH) based colloidal silica slurry could not realize a mirror surface without physical defects, resulting in low material removal rate and many scratches on surface. In order to enhance chemical reaction such as form oxidized layer on the surface of cadmium telluride, we used hydrogen peroxide ($H_2O_2$) as an oxidizer. Consequently, in case of 3 wt% concentration of hydrogen peroxide, the highest MRR (938 nm/min) and the lowest surface roughness ($R_{p-v}=10.69nm$, $R_a=0.8nm$) could be obtained. EDS was also used to confirm the generated oxide of cadmium telluride surface.