• Computers and Concrete
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• v.12 no.3
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• pp.319-335
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• 2013

In this paper, the properties of the cement mortar modified with styrene acrylic ester copolymer were investigated. Expanded vermiculite as lightweight aggregate was used for making the polymer modified mortar test specimens. To study the effect of polymer-cement ratio and vermiculite-cement ratio on various properties, specimens were prepared by varying the polymer-cement and vermiculite-cement ratios. Tests of physical properties such as density, water absorption, thermal conductivity, three-point flexure and compressive tests were made on the specimens. Furthermore, a coupled thermal-structural finite element model of an entire corner wall was modelled in order to study the best material configuration. The wall is composed by a total of 132 bricks of $120{\times}242{\times}54$ size, joined by means of a contact-bonded model. The use of advanced numerical methods allows us to obtain the optimum material properties. Finally, comparisons of polymer-cement and vermiculite-cement ratios on physical properties are given and the most important conclusions are exposed.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.7 no.1
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• pp.18-26
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• 1998

The improvement of esthetic dentistry has been accelerated from the development of composite resin and dentin-enamel adhesive since 1980's. The indirect composite resin restorations have more accurate proximal contact point and occlusal form than direct restoration. And the side effect of resin shrinkage is minimal because the amount of composite used in oral cavity is limited in cement space. As a results, marginal leakage, hypersensitivity, secondary caries, and discoloration are significantly diminished. The first generation laboratory composite resin used in indirect resin restoration had been widespread in 1980's and the second generation laboratory composite resins were developed in 1990's. The second generation laboratory composite resins are called Ceramic Polymer. The physical properties of Ceramic Polymer are improved because of high content of inorganic filler, and the esthetics and biocompatibility are better than that of the first generation resin. So the application range using composite resin have been broadened. The purpose of this paper is to introduce Targis & Vectris system that is classified to second generation laboratory composite and to report several cases in which the system was utilized for restoration.

• Journal of agricultural medicine and community health
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• v.1 no.1
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• pp.22-28
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• 1976

It has been well known that indiscriminative use of pesticides contaminates water resources and soil to break down the balance of natural ecosystem and brings acute when spray. In this country, 62,602 tons of pesticides were used in 1974 for agricultural purpose figuring 28.0 kg per hectare which showed 20% increasement every year since 1970. It is almost impossible to figure out incidence and mortality of acute pesticide poisoning exactly. However, a survey in 1974 reported that 33.5% of male and 32.7% of female who sprayed certain pesticides complained of several symptoms seemed to be due to acute pesticide poisoning. It also mentioned that the main cause inducing poisoning supposedly was dusting without protective armamation such as masks, booths, gloves and others in more than 60% of above cases. Pesticide poisoning through contamination of food or direct inhalation and contact. With the reason, the followings can be recommended to minimize or prevent pesticide hazards. 1. Strict legal control 2. Systematic education on the safe handling way of pesticides for the people who are to use them. 3. Remarkable warning at transportation and stocking of pesticides. 4. Obligatory attachment of explanation on the package about effect, safe handling method, and. emergency care at acute pesticide poisoning concerned.

• Textile Coloration and Finishing
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• v.23 no.4
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• pp.284-289
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• 2011

Poly(phenylene sulfide)(PPS) films were photooxidized under UV/ozone irradiation. The effect of UV energy on the surface properties of the UV-irradiation PPS films were investigated by the measurement of reflectance, surface roughness, and contact angle. Reflectance decreased at the wavelength of 400nm and the surface roughness increased with increased UV energy. The improvement in hydrophilicity with increased $O_{1s}/C_{1s}$ was caused by the introduction of hydrophilic $SO_2$ bond. Surface energy increased from 46.6 to $78.3mJ/m^2$ with increased UV energy up to $21.2J/cm^2$. Also zeta potential decreased with increased UV energy. The increased dyeability to cationic dyes may be due to the photochemically introduced anionic and dipolar dyeing sites on the PPS films surfaces.he photochemically introduced anionic and dipolar dyeing sites on the PPS films surfaces.

• Journal of Korean Academy of Nursing
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• v.36 no.4
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• pp.645-651
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• 2006

Purpose. This study investigated changes in attitudes toward elders in general and elders with dementia after students finished a gerontological nursing practicum. Methods. Questionnaires developed for Asian cultures were administered pre practicum, immediately post practicum, and at 8-months follow up to 31 senior students in a baccalaureate nursing program. The 1-week practicum occurred at two adult day care centers: a center for elders with dementia and a center for elders with stroke. Repeated measures ANOVA and Bonferroni correction procedures were used to analyze data. Results. Students' evaluation of elder vitality and flexibility increased significantly at post practicum, however this increase was not sustained at follow up. Score of generosity of elders, the only positively evaluated dimension for elders in general, improved partly at post practicum. Students evaluated flexibility and generosity of elders with dementia more negatively than general elders. All of the decreased attitudes at follow up were not significantly different from those at pre practicum. Conclusions. Students had more negative attitudes toward elders with dementia. Attitudes of students in direct contact with elders with dementia were improved through the practicum regarding generosity and flexibility. However the sustainability of the immediate effect was not observed at follow up.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.17-17
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• 2009

Single-walled carbon nanotubes (SWCNTs) have attracted much attention as promising materials for transparent conducting films (TCFs), thanks to their superior electrical conductivity, high mechanical strength, and complete flexibility. The CNT-based TCFs can be used in a variety of application fields as flexible, transparent electrodes, including touch panel screens, flexible electronics, transparent heaters, etc. First of all, this study investigated the effect of a variety of surfactants on the dispersion of SWCNTs in an aqueous solution. Following the optimization of the dispersion by surfactants, flexible TCFs were fabricated by spraying the CNT suspension onto poly(ethylene terephthalate) (PET) substrates. The sheet resistances of the TCFs having different surfactants were investigated with treatment in nitric acid ($HNO_3$) whose concentration and period of treatment time were varied. It seems that the $HNO_3$ removes the surfactants from and is simultaneously doped into the SWCNT network, reducing the contact resistance between CNTs. TCFs were characterized by UV-VIS spectroscopy, thermogravimetric analyzer (TGA), scanning electron microscopy (SEM), and four-point probe.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.3991-3995
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• 2011

$TiO_2-SiO_2-In_2O_3$ nanocomposite thin film was deposited on the glass substrates using a dip coating technique. The morphology, surface composition, surface hydroxyl groups, photocatalytic activity and hydrophilic properties of the thin film were investigated by AFM, XPS, methyl orange decoloring rate and water contact angle measurements. The hydroxyl content for $TiO_2$, $TiO_2-SiO_2$ and $TiO_2-SiO_2-In_2O_3$ nanocomposite films was calculated to be 11.6, 17.1 and 20.7%, respectively. $TiO_2-SiO_2-In_2O_3$ film turned superhydrophilic after 180-min irradiation with respect to pure $TiO_2$ and $TiO_2-SiO_2$ thin films. The photocatalytic decomposition of methyl orange for $TiO_2$, $TiO_2-SiO_2$ and $TiO_2-SiO_2-In_2O_3$ thin films was measured as 38.19, 58.71 and 68.02%, respectively. The results indicated that $SiO_2$ and $In_2O_3$ had a significant effect on the hydrophilic, photocatalytic and self-cleaning properties of $TiO_2$ thin film.

• Korean journal of applied entomology
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• v.43 no.2
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• pp.169-173
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• 2004

Control effects of some insecticides were evaluated against the stone leek leafminer, Liriomyra chinensis Kato (Diptera： Agromyzidae) with the some different treatment methods. Insecticidal activities effects were estimated on the different development stages of the insects on welsh onion. The insecticides that controlled L. chinensis eggs with over 83％ efficacy were spinosad, dimethoate, emamectin, and cartap. The insecticides that showed over 87％ of larvicidal activity were dimethoate and cartap. Dimethoate showed 93.3％ insecticide residual activity for 3 days a(ter treatment as a foliar spray. For control of pupae, the insecticides that showed over 88％ of contact insecticidal activity were terbufos GR and cartap GR. Both dimethoate and cartap had high adulticidal activity with over 95％ control efficacy.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.360.2-360.2
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• 2016

CuSn thin films were fabricated by rf magnetron co-sputtering method on the Si(100) substrate for evaluation of the antibacterial effect. The co-sputtering process was performed with different rf powers and sputtering times to regulate the thickness of the films and relative atomic ratio of Cu to Sn. The physicochemical properties of the CuSn thin films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray induced Auger electron spectroscopy (XAES), Optical microscope (OM), 4-point probe, and antibacterial test. An antibacterial test was conducted with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as changing contact times between CuSn fillms and bacteria suspension. We compared to the crystalline structures of films before sterilization and after sterilization by XRD measurement. The changes of oxidation states of Cu and Sn and the chemical environment of films before and after antibacterial test were investigated with high resolution XPS spectra in the regions of Cu 2p, Cu LMM, and Sn 3d. After antibacterial test, the morphology of the films was checked with an OM images. The electrical properties of the CuSn films such as surface resistance and conductivity were measured by using 4-point probe.

• Journal of Welding and Joining
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• v.35 no.1
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• pp.43-48
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• 2017

Pulse TIG (Tungsten Inert Gas) welding is often considered the most difficult of all the welding processes commonly used in industry. Because the welder must maintain a short arc length, great care and skill are required to prevent contact between the electrode and the workpiece. Pulse TIG welding is most commonly used to weld thin sections of stainless steel, non-ferrous metals such as aluminum, magnesium and copper alloys. It is significantly slower than most other welding techniques and comparatively more complex and difficult to master as it requires greater welder dexterity than MIG or stick welding. The problems associated with manual TIG welding includes undercutting, tungsten inclusions, porosity, Heat affected zone cracks and also the adverse effect on health of welding gun operator due to amount of tungsten fumes produced during the welding process. This brings the necessity of automation. Hence, In this paper an attempt has been made to build a customerized setup of Pulse TIG welding based on through review of Pulse TIG welding parameters. The cost associated for making automated TIG is found to be low as compared to SPM (Special Purpose machines) available in the market.