• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.988-992
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• 2002

Ultrasonic machining technology has been developed over recent years for the manufacture of and quality-assured precision parts for several industrial application such as optics, semiconductors, aerospace, and automobile application. The past decade has seen a tremendous in the use of ceramics in structural application. The excellent thermal, chemical and wear resistance of these material can be realized because of recent improvements in the overall strength and uniformity of advanced ceramics. Ultrasonic machining, in which abrasive particles in slurry with water are presented to the work surface in the presence of an ultrasonic-vibrating tool, is process which should be of considerable interest, as its potential is not limited by the electrical or chemical characteristics of the work material, making it suitable for application to ceramics. This paper intends to further the understanding of the basic mechanism of ultrasonic machining for brittle material and ultrasonic machining of ceramics based in the fracture-mechanic concept has been analyzed.

• Textile Coloration and Finishing
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• v.13 no.6
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• pp.413-427
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• 2001

In this studs, we synthesized durable antistatic agents with acrylic monomers for preventing the electrification of static electricity which is one of defects of polyester fabrics. Also we synthesized quaternary ammonium salts which give antistatic property and crosslinking agents which make antistatic agents adhere to fiber. The treatment of synthesized antistatic agents on polyester fabric carried out at the condition of various concentrations, treatment times and temperatures. The antistatic property, handle characteristics and other properties of treated and untreated polyester fabrics were also investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.540-540
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• 2013

In this studying, we investigated the basic properties of N-doped plasma polymer. The N-doped ethylcyclohexane plasma polymer thin films were deposited by radio frequency (13.56 MHz) plasma-enhanced chemical vapor deposition method. Ethylcyclohexenewas used as organic precursor (carbon source) with hydrogen gas as the precursor bubbler gas. Additionally, ammonia gas [NH3] was used as nitrogen dopant. The as-grown polymerized thin films were analyzed using ellipsometry, Fourier-transform infrared [FT-IR] spectroscopy, Raman spectroscopy, FE-SEM, and water contact angle measurement. The ellipsometry results showed the refractive index change of the N-doped ethylcyclohexene plasma polymer film. The FT-IR spectrashowed that the N-doped ethylcyclohexene plasma polymer films were completely fragmented and polymerized from ethylcyclohexane.

• Membrane and Water Treatment
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• v.6 no.2
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• pp.95-102
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• 2015

The presented research is about characterization of Cellulose Triacetate (CTA) based Polymer Inclusion Membranes (PIMs) which incorporated the commercial extractant Aliquat 336, Tributylphosphate (TBP) as modifier and 2-Nitro Phenyl Pentyl Ether (NPPE) as plasticizer, for the preparation of the membranes. Chemical and physical characteristics of the synthesized membranes especially membrane thickness and side difference effects were investigated. Different surface structures and membrane thickness affect the extraction efficiency of membranes. Membrane extraction experiments were studied where the glass-facing surface of the membranes placed next to feed phase and the air-facing surface to stripping phase. The membrane was characterized by means of AFM, FT-IR and SEM.

• Journal of the Korean Applied Science and Technology
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• v.17 no.2
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• pp.126-131
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• 2000

Transdermal therapeutic system(TTS) is often used as the method of drug dosage into the epidermic skin. Natural polymer were selected as ointment material of TTS. We investigated the permeation of natural polymer ointment containing drug in rat skin using horizontal membrane cell model. Permeation properties of materials were investigated for water-soluble drug such as oxiniacic acid in vitro. These results showed that skin permeation rate of drug across the composite was mainly dependent on the property of ointment base and drug. Proper selection of the polymeric materials which resemble and enhance properties of the delivering drug was found to be important in controlling the skin permeation rate. This result suggests a possible use of natural polymer ointment base as TTS of antihyperlipoproteinemic agent.

• Journal of the Korean Applied Science and Technology
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• v.26 no.2
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• pp.224-231
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• 2009

Techniques measuring Maxwell displacement current (MDC) and LB films surface measuring technique have been applied to the study of monolayers of polyamic acid containing azobenzene. MDCs was generated from monolayers on the water surface by monolayer compression and expansion. It was generated when the area per molecule was about $103{\AA}^2\;and\;78{\AA}^2$ just before the initial rise of the surface pressure during the 1st and 2nd mixed monolayer compressions cycle, respectively. It was the maximum of MDCs appeared at the molecular area just before the initial rise of surface pressure in compression cycles, and we have found that the increase of aggregations causes the noticeable increase of the surface roughness.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.519-522
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• 2005

As this study is to test effects of chemical attack on deterioration of cement mortars using in crushed sand. Besides tests have been carried out with cement mortars by river sand and crushed sand by fine sand, cement mortars mix various proportions of slica fume and fly ash(up to $15\%$ and $50\%$ by weight for cement) were prepared and immersed in pure water, sodium sulfate solution, magnesium sulfate solution, seawater for 28days. Test on the change in the weight and compressive strength of cement mortars according to the duration of immersion time and the content of slica fume and fly ash was performed.

• Proceedings of the Korean Geotechical Society Conference
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• 2004.03b
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• pp.189-196
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• 2004

In this study, the colloidal silica grouts (PSG) with novel chemical compositions for permanent reinforcement and water cut-off of the ground were prepared and their engineering charateristics were investigated. The optimum mixing recipes for both homogeneous solution grouts and heterogeneous suspension grouts were investigated and established through many repeated lab tests. The various physical properties(such as compressive strength, durability and syneresis) of the grout gels derived from the colloidal silica were investigated and compared with those of the well-known existing watergalss grouts. The all experimental results showed that the novel colloidal silica grouts(PSG) had greatly excellent performances as permanent grouts, especially in comparison with the existing watergalss grouts.

• Journal of the Korean Chemical Society
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• v.16 no.3
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• pp.149-156
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• 1972

The responsive characteristics of hydrogen-responsive glass electrode in various buffer solutions of methanol, N,N-dimethylformamide and acetonitrile were examined. The potentials were attained more rapidly with an electrode stored in the same solvent medium than that stored in water before use. However, the time to be required for a stable potential increased with the basicity of buffer solution, and it was not provide a constant potential in the strong basic solution of these solvent. Even in acidic solution, the potential was varied according to the past usage of the electrode.

• Journal of the Korean Chemical Society
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• v.21 no.5
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• pp.384-388
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• 1977

Clay-polymer thickened greases were made by dispersing bentone-polyethylene and bentone-atactic polypropylene into mineral oil at an adequate temperature, and the physical properties such as wear and water washout characteristics, oxidation and shear stabilities, and dropping point of the greases were tested. Even if the greases failed to meet some properties, it was found that those greases can be used for some special purposes, by observing and comparing the properties with those of clay-metallic soap thickened greases that were made in this experiment.