• Food Science of Animal Resources
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• v.32 no.5
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• pp.561-570
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• 2012

The objective of this study was to evaluate the effects of an atmospheric pressure plasma (APP) jet on L. monocytogenes inactivation, quality characteristics, and genotoxicological safety of cooked egg white and yolk. APP treatment using He gas resulted in a 5 decimal reduction in the number of L. monocytogenes in cooked egg white, whereas that using $He+O_2$, $N_2$, and $N_2+O_2$ decreased the number further, and to undetectable levels. All treatments of cooked egg yolk resulted in undetectable levels of inoculated L. monocytogenes. There were no viable cells of total aerobic bacteria after APP treatment on day 0 while the control showed approximately 3-4 Log CFU/g. On day 7, the numbers of total aerobic bacteria had increased by approximately 3 log cycles in cooked egg white, but there were no viable cells in cooked egg yolk after 2 min of APP jet. APP treatment decreased the $L^*$-values of cooked egg white and yolk significantly on day 0. No significant sensory differences were found among the cooked egg white samples, whereas significant reductions in flavor, taste, and overall acceptability were found in cooked egg yolks treated with APP jets. SOS chromotest did not reveal the presence of genotoxic products following APP treatments of cooked egg white and yolk. Therefore, it can be concluded that APP jets can be used as a non-thermal means to enhance the safety and extend the shelf-life of cooked egg white and yolk.

• Laser Solutions
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• v.11 no.4
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• pp.29-34
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• 2008

Ultraviolet laser micromachining has increasingly been applied to the electronics industry where precision machining of high-density, multi-layer, and multi material components is in a strong demand. Due to the ever-decreasing size of electronic products such as cellular phones, MP3 players, digital cameras, etc., flexible printed circuit board (FPCB), multi-layered with polymers and metals, tends to be thicker. In present, multi-layered FPCBs are being mechanically cut with a punching die. The mechanical cutting of FPCBs causes such defects as burr on layer edges, cracks in terminals, delamination and chipping of layers. In this study, the laser cutting mechanism of FPCB was examined to solve problems related to surface debris and short-circuiting that can be caused by the photo-thermal effect. The laser cutting of PI and FCCL, which are base materials of FPCB, was carried out using a pico-second laser(355nm, 532nm) and nano-second UV laser with adjusting variables such as the average/peak power, scanning speed, cycles, gas and materials. Points which special attention should be paid are that a fast scanning speed, low repetition rate and high peak power are required for precision machining.

• The Journal of Advanced Prosthodontics
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• v.12 no.4
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• pp.181-188
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• 2020

PURPOSE. The effect of core design on the fracture resistance of zirconia-lithium disilicate (LS2) bilayered crowns for anterior teeth is evaluated by comparing with that of metal-ceramic crowns. MATERIALS AND METHODS. Forty customized titanium abutments for maxillary central incisor were prepared. Each group of 10 units was constructed using the same veneer form of designs A and B, which covered labial surface to approximately one third of the incisal and cervical palatal surface, respectively. LS2 pressed-on-zirconia (POZ) and porcelain-fused-to-metal (PFM) crowns were divided into "POZ_A," "POZ_B," "PFM_A," and "PFM_B" groups, and 6000 thermal cycles (5/55 ℃) were performed after 24 h storage in distilled water at 37 ℃. All specimens were prepared using a single type of self-adhesive resin cement. The fracture resistance was measured using a universal testing machine. Failure mode and elemental analyses of the bonding interface were performed. The data were analyzed using Welch's t-test and the Games-Howell exact test. RESULTS. The PFM_B (1376. 8 ± 93.3 N) group demonstrated significantly higher fracture strength than the PFM_A (915.8 ± 206.3 N) and POZ_B (963.8 ± 316.2 N) groups (P<.05). There was no statistically significant difference in fracture resistance between the POZ_A (1184.4 ± 319.6 N) and POZ_B groups (P>.05). Regardless of the design differences of the zirconia cores, fractures involving cores occurred in all specimens of the POZ groups. CONCLUSION. The bilayered anterior POZ crowns showed different fracture resistance and fracture pattern according to the core design compared to PFM.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.635-635
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• 2013

We report three-dimensional polycrystalline anatase TiO2 structures (3D a-TiO2) for environmental and bio-medical applications. The 3D a-TiO2 was synthesized without thermal treatment by the growth of rod-like polycrystals on Degussa P25 (P25) via low temperature (< $85^{\circ}C$) modified alkali hydrothermal processing. X-ray diffraction and high-resolution transmission electron microscopic results showed that the rod-like polycrystals of 3D a-TiO2 possessed the highly anatase nanostructures. The photocatalytic activity of 3D a-TiO2 was found to be 2.2 times higher than that of P25. The recyclability of the 3D a-TiO2 was found to be high: the decolorization rate was 94.8% of the initial value after fifteen cycles. In addition, 3D a-TiO2 exhibited excellent antibacterial activities for the sterilization of gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus). Even at the 10th recycled use, more than 98.4% of E. coli and S. aureus can be killed. These results indicated that 3D a-TiO2 might have utility in several promising applications such as photocatalytic water/air purification and bactericidal agents.

• Restorative Dentistry and Endodontics
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• v.15 no.1
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• pp.44-56
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• 1990

This study was designed to assess the degree of the marginal leakage of posterior composite restorations with glass ionomer cement base and Scotchbond$^{(R)}$ by means of the dye penetration at the enamel and dentinal margins. 160 cavities of class V were prepared on the buccal and lingual surfaces of 80 extracted premolar and molar teeth, which were divided into two groups. The buccal cavities of one group were filled with GC lining cement$^{(R)}$, Scotchbond$^{(R)}$ and P 50$^{(R)}$ and the lingual cavities were filled with Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$. The Buccal cavities of other group were filled with Logobond$^{(R)}$, Scotchbond$^{(R)}$ and Heliomolar$^{(R)}$ and lingual cavities were filled with Scotchbond$^{(R)}$ and P 50$^{(R)}$. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$ and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours and buccolingually sectioned with diamond disc. The sectioned specimens were examined under light microscope. The following results were obtained. 1. The group filled with glass ionomer cement base showed less marginal leakage than the group filled without glass ionomer cement base. 2. The enamel margins showed less microleakage than the dentinal margins in both of the two groups. 3. No significant difference was showed in the microleakage, irrespective of two glass ionomer cement base and posterior composite resin.

• Restorative Dentistry and Endodontics
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• v.12 no.1
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• pp.107-116
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• 1986

The primary aim of this study was to assess the effects of the margin designs and composite resins on the marginal leakage of Class V resin restorations. 60 Class V cavities with $90^{\circ}$ butt joint, 60 with $45^{\circ}$ bevel joint, and 60 with concave joint were prepared on the labial surfaces of 38 extracted anterior teeth and the buccal and lingual surfaces of 71 premolars, and classified as the butt group, bevel group and concave group, respectively. After completion of the cavity preparation, Heliosit${(R)}$ was filled in 20 butt joint cavities, 20 bevel joint cavities, and 20 concave cavities. And Hi-Pol$^{(R)}$ and Palfique$^{(R)}$ were filled in the same manner, respectively. After finishing, all specimens were subjected manually to 50 thermal cycles at $4^{\circ}C$, $37^{\circ}C$, and $60^{\circ}C$. They were immersed in 0.5% methylene blue solution for 24 hours, and buccolingually sectioned with sectioning machine. The sectioned specimens were examined under the light microscope. The results indicated the following: 1. The bevel group showed the least amount of marginal leakage compared with the other two design groups, but the statistical analysis showed no significant difference at the 95% confidence level. 2. Hi-Pol$^{(R)}$ group showed the most severe marginal leakage compared with the other composite resin materials, but there was no significant difference in the groups. 3. The bevel-Heliosit$^{(R)}$ subgroup, which was filled with Heliosit$^{(R)}$ in the beveled cavities, showed the least amount of marginal leakage, but there was no significance in all the subgroups.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.39-45
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• 1998

SrBi$_{2}$Ta$_{2}$O$_{9}$ (SBT) ferroelectric thin films for nonvolatile memory were prepared on Pt/Ti/SiO$_{2}$/Si and RuO$_{2}$/SiO$_{2}$/Si substrates by RF magnetron sputtering. The dependences of crystalline and electrical properties on the lower electrode type(Pt and RuO$_{2}$) and the annealing temperatures were investigated. SBT films regardless of their electrode types showed typeical Bi layered peroviskite crystal structures. The crystalline quality of as-deposited SBT films was improved by the rapid thermal annealing at 650.deg. C for 30 sec. The remanetn polarization of 2Pr (Pr+-Pr-) of the annealed SBT films deposited on Pt/Ti/SiO$_{2}$/Si substrates were about 11 .mu.C/cm$^{2}$ and 3 .mu.C/cm$^{2}$, respectively. The leakage currents at 3 V bias voltage were about 0.8 .mu.A/cm$^{2}$ for SBT/ Pt/Ti/SiO$_{2}$/Si and about 1 .mu.A/cm$^{2}$ for SBT/RuO$_{2}$/SiO$_{2}$/Si sample. SBT films annealed at 650 .deg. C showed no degradation in Pr values after 10$^{11}$ polarization switching cycles, indicating good fatigue properties. In addition, for SBT samples deposited on Pt/Ti/SiO$_{2}$/Si, Pr values increased to more than that of initial state, suggesting the increament of leakage current caused by repeated polarization.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.117-123
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• 2016

Glass wool is a material that has been used as a heat insulator in various fields including construction industry. Since it is a nonflammable material, it does not generate toxic gases on fire, and thus public agencies recommend using glass wool as a heat insulator instead of other organic materials. However, repeated drying and wetting cycles can deteriorate thermal property of glass wool due to the shrinkage and reduction in pore size. For this reason, it needs to be replaced periodically, and waste materials are generated. This research aims to utilize waste glass wool as additives for increasing mechanical properties of concrete. According to the experimental results, it was found that glass wool has weak pozzolanic activity, and beneficial effect on both compressive and flexural strength. The optimum amount found in this experimental work was 0.5% volumetric addition to the concrete.

• Fashion & Textile Research Journal
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• v.1 no.3
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• pp.288-295
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• 1999

This study was conducted to examine the fatigue phenomenon of mechanical properties in tencel fabrics by repeated washing & shear and tensile deformation. The obtained results are as follows. After performing repeated shear tensile deformation, RT of tencel showed higher increase rate than that of cotton and rayon, whereas its WT and EM was a smaller decrease rate than that of them. This means that tencel's resistance to tensile deformation was the greatest. In the repeated washing and shear tensile deformation, tencel's 2HB, 2HG and 2HG5 showed a remarkable increase rate. In terms of deformation frequency, the greatest change rate appeared at the time of 1000 cycles of repeated shear tensile deformation and 15 times of repeated washing. In the hand value and THV, KOSHI showed a higher increase rate for tencel than for cotton and rayon in both repeated washing and shear tensile deformation, and NUMERI showed a higher increase rate. In the THV the change rate of rayon and cotton could be rarely seen but for tencel, it decreased. tencel's change rate of thermal insulation value by materials was 1.08%, and it increased as the washing frequency increased, compared to the grey fabrics, whereas the change rates of cotton and rayon were 0.74% and 0.22%, respectively. The qmax decreased in the order of cotton>tencel>rayon as the washing frequency increased.

• Composites Research
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• v.16 no.1
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• pp.26-33
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• 2003

Utilizing a thermo-acoustic emission (AE) technique, a study on detection and evaluation of microfractures in cross-ply laminate composites was performed. Fiber breakages and matrix fractures formed by a cryogenic cooling at $-191^{\circ}C$ were observed with ultrasonic C-scan, optical and scanning electron microscopy. Those microfractures were monitored in a non-destructive in-situ state as three different types of thermo-AE signals classified on the basis of Fast-Fourier Transform and Short-Time Fourier Transform. Thus, it was concluded that real-time estimation of microfracture processes being formed during cryogenic cooling could be accomplished by monitoring such different types of thermo-AEs in each time-stage and then by analyzing thermo-AE behaviors for the respective AE types on the basis of the AE signal analysis results obtained during thermal heating and cooling load cycles.