• The Journal of Advanced Prosthodontics
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• v.9 no.6
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• pp.482-485
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• 2017

PURPOSE. This laboratory study aimed to investigate the effect of doping an acrylic denture base resin material with nanoparticles of ZnO, CaO, and $TiO_2$ on biofilm formation. MATERIALS AND METHODS. Standardized specimens of a commercially available cold-curing acrylic denture base resin material were doped with 0.1, 0.2, 0.4, or 0.8 wt% commercially available ZnO, CaO, and $TiO_2$ nanopowder. Energy dispersive X-ray spectroscopy (EDX) was used to identify the availability of the nanoparticles on the surface of the modified specimens. Surface roughness was determined by employing a profilometric approach; biofilm formation was simulated using a monospecies Candida albicans biofilm model and a multispecies biofilm model including C. albicans, Actinomyces naeslundii, and Streptococcus gordonii. Relative viable biomass was determined after 20 hours and 44 hours using a MTT-based approach. RESULTS. No statistically significant disparities were identified among the various materials regarding surface roughness and relative viable biomass. CONCLUSION. The results indicate that doping denture base resin materials with commercially available ZnO, CaO, or $TiO_2$ nanopowders do not inhibit biofilm formation on their surface. Further studies might address the impact of varying particle sizes as well as increasing the fraction of nanoparticles mixed into the acrylic resin matrix.

• Journal of Biosystems Engineering
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• v.26 no.2
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• pp.141-146
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• 2001

Lots of the agricultural information come from human experiences and are in non-numerical forms. Therefore, it is difficult to process to be processed in a conventional data processing way. An internet expert system for agricultural application using the ASP(active server page) was developed to solve this problem and consisted of databases, an inference engine, and an user interface. The databases were composed of rule base, question base and link data. The inference engine was developed with the ASP for connection with web between databases. The used interface was developed with the CGI(common gateway interface), so that question could be answered on a web browser, and the session technique was used to provide proper result to each of multi-users. A prototype internet expert system was developed for diagnosis of diseases and nutritional disorders of paddy rice. The expert system was interactively worked through WWW(world wide web) at remote sites by multi-users, even at the same time. The rule base could be easily updated and modified from a web server computer by a knowledge engineer.

• Journal of the Korean Applied Science and Technology
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• v.22 no.2
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• pp.142-150
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• 2005

The natural graphite particles A and heat-treated graphite particles B at $1800\;^{\circ}C$ after pitch-coating were used as the anode base materials for lithium ion secondary battery. In order to improve the performance of anode materials, the base anode materials were treated with various acids. With the acid treatments of 62% $HNO_3$ and 95% $H_2SO_4$ aqueous solution, the specific surface area and electrical conductivity of base anode materials were increased, and the initial charge-discharge capacity and cycle performance were improved due to the elimination of structural defects.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10a
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• pp.35-36
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• 2003

The purpose of this work is to investigate the surface modification of LDPE film via corona discharge treatment and subsequent graft polymerization, and their effect on the resulting dyeability is studied in terms of the surface functional groups, surface energetics, and acid-base interaction between the modified LDPE and the dyes used.

• Journal of Korean Foot and Ankle Society
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• v.8 no.1
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• pp.92-96
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• 2004

Purpose: To analyze the clinical and radiological results of the operative treatment in the avulsion fracture on the base of the fifth metatarsal. Materials and Methods: We studied retrospectively, 11 patients of avulsion fracture on the base of the fifth metatarsal operated and followed over 1 year, from February 2000 to May 2002. There were eight men and three women and the average age was 39 years old. The mean follow up period was 14 months. Ten cases were slip-down and one case was fall from a height injuries. We used the modified Foot Score by Wiener for the clinical evaluation, and analyzed the time of union and state of reduction radiologically. Results: In clinical results, we had ten excellent and one good cases by the modified Foot Score at last follow-up. In radiologic results, the complete bony union was achieved in all cases and the duration of the bony union was 37 days in average. Conclusion: We had good result for the avulsion fractures on the base of the fifth metatarsal treated by the operation. This study shows the operation was recommended for the moderate and severe displacement of the avulsion fractures on the base of the fifth metatarsal.

• Nuclear Engineering and Technology
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• v.53 no.6
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• pp.1887-1892
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• 2021

The effect of gadolinium and boron on the texture development and magnetic properties of the texture controlled 23Cr-10NiCu duplex stainless steels were studied to develop a high performance neutron and electromagnetic shielding material. The 23Cr-10NiCu base alloy is composed of 60% of austenite and 40% of ferrite, whereas, the 23Cr-10NiCu-0.5Gd-0.8B modified alloy is composed of 66% of austenite, 27% of ferrite and 7% of CrFeB intermetallic compounds. The gadolinium and boron addition to the 23Cr-10NiCu base alloy increased mechanical properties. Microstructure observation showed that the small addition of 0.5 wt% gadolinium and 0.8 wt% boron to the alloy retarded to form texture at the same hot rolling conditions, and improved the maximum magnetism, residual magnetism and coercive force about 3%, 122% and 120%, respectively.

• Imaging Science in Dentistry
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• v.30 no.4
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• pp.243-248
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• 2000

Purpose: The aim of this study was to determine the relative radiopacities of cavity lining materials (Resin-modified Glass Ionomer cement, Compomer and Plowable resin) for posterior composite resin restoration. Material & Methods: Resin-modified glass ionomer cement (Fuji II LC, Vitrebond/sup TM/), Compomers (Dyract /sup (R)/ Compoglass, F2,000, Dyract/sup (R)/ flow Compoglass Flow) and Flowable resins (Tetric/sup (R)/ flow, Aeliteflo/sup TM/ Revolution/sup TM/) were used. Five specimens of 5 mm in diameter and 2 mm thick were fabricated with each material. Human molars were horizontally sectioned 2 mm thick to include both enamel and dentin. The radiopacities of enamel, dentin, cavity lining materials, aluminum step wedge were obtainded from conventional radiograph and NIH image program. Results: All the tested lining materials showed levels of radiopacity the same as or greater than that of dentin. All compomer tested (Dyract, Compoglass, F2,000, Dyract flow, Compoglass Flow) and Vitrebond/sup TM/, Tetric/sup (R)/ flow were more radiopaque than enamel. The radiopacities of Fuji II LC and Revolution/sup TM/ were between enamel and dentin and resin-modified glass ionomer cement, Compomer and Tetric/sup (R)/ flow were greater than those of Revolution/sup TM/, Aeliteflo/sup TM/ or dentin. The level of radiopacity of the tested materials was variable; those with low radiopacity should be avoided in class II restorations, where a clear determination of recurrent caries by the examining clinician could be compromised. Conclusion: Clinician should be able to distinguish these cavity lining materials radiographically from recurrent decay, voids, gaps, or other defects that lead to clinical failure. Utilization of materials ranked more radiopaque than enamel would enable clinicians to distinguish the lining material from tooth structure.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.865-867
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• 2009

In this paper, we describe the fabrication of nano-scale ink particles with narrow size distribution to offer high optical density in electrophoretic display applications. Charged white ($TiO_2$ and polyester) and black (carbon black and polyester) nano size ink particles in size range of 200 ~ 700nm were made successively using modified non-aqueous base emulsion process. The EPD showed white reflectance of 58% and saturation voltage of ${\pm}10V$.

• Journal of the Korean institute of surface engineering
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• v.39 no.4
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• pp.166-172
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• 2006

Metallized Polyimide films are extensively used as base materials in microelectronics, optical and automotive applications. However it is difficult to deposit metals on those because of their structural stabilities. In this work, polyimide films are modified by a wet process with alkalinemetalhydroxide and additives to introduce functional groups. The surface molecular structures of polyimide are investigated using X-ray photoelectron spectroscopy(XPS), fourier transform infrared reflection spectroscopy(FTIR-ATR), atomic force micro-scopic(AFM). XPS spectra and FTIR spectra show that the surface structure of polyimide is converted into potassium polyamate. AFM image and AFM cross-sectional analyses reveal the increased roughness on the modified surface of polyimide films. As a result, it is shown that the adhesion strength between polyimide surface and electroless nickel layer is increased by the nano-anchoring effect.

• Journal of Electrochemical Science and Technology
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• v.15 no.2
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• pp.220-241
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• 2024

Due to its unique advantages, electrochemical machining (ECM) is playing an increasingly significant role in the manufacture of difficult-to-machine materials. Most of the current ECM research is conducted at room temperature, with studies on ECM in a cryogenic environment not having been reported to date. This study is focused on the electrochemical dissolution characteristics of typical iron and nickel base alloys in NaNO₃ solution at low temperature (-10℃). The polarization behaviors and passive film properties were studied by various electrochemical test methods. The results indicated that a higher voltage is required for decomposition and more pronounced pitting of their structures occurs in the passive zone in a cryogenic environment. A more in-depth study of the composition and structure of the passive films by X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy showed that the passive films of the alloys are modified at low temperature, and their capacitance characteristics are more prominent, which makes corrosion of the alloys more likely to occur uniformly. These modified passive films have a huge impact on the surface morphologies of the alloys, with non-uniform corrosion suppressed and an improvement in their surface finish, indicating that lowering the temperature improves the localization of ECM. Together with the cryogenic impact of electron energy state compression, the accuracy of ECM can be further improved.