• 상하수도학회지
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• 제28권5호
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• pp.589-600
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• 2014

Tuberculation and slime accumulated in water mains play an important role in modifying water quality of drinking water. Therefore, in this study, it was investigated that what materials were accumulated, and what components were included in the tuberculation and slime of water mains. The Various tuberculation and slime sample were collected from the 12 water mains to analyze their physical and chemical properties and crystal structure. As a analysis method, VSS(Volatile suspended solid), SEM(scanning electron microscope), EDS(Energy Dispersive X-ray spectroscope), ICP(Inductively Coupled Plasma Mass Spectrometer) and XRD(X-Ray Diffractomete) were used. The results of analysis on the samples, the representative materials were verified such as iron corrosion products, the fine sand particles generated during backwash, fine particles of activated carbon, aluminum used in coagulation process, and manganese included in raw water.

• 수산해양기술연구
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• 제50권1호
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• pp.50-57
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• 2014

The performance of five kind adsorbents, which can reduce nitrogen oxide (NOx) from the diesel engine occupying 85% of the fishing boat, was carried out and the emission reduction filter was manufactured and evaluated in the adsorption efficiency of the emission gas for 240 KW diesel portable generator. As a NOx emission filter made of mordenite which has an excellent cation exchange capacity was manufactured by ball type adsorbents having excellent specific surface area. The adsorption efficiency of mordenite material applying the emission reduction filter began to show up at the operating time 10 minutes in comparison with the activated carbon and zeolite materials, and it was exposed to continue until 100% capability with passing by 20 minutes. So the adsorption efficiency of the NOx reduction filter consistently maintained at the averaged 80%.

• 한국수산과학회지
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• 제44권3호
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• pp.216-224
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• 2011

Capsosiphon fulvescens is well-known green sea algae that, in recent years, has been proposed as a potential anticancer drug. In this study, we found that C. fulvescens glycoprotein (Cf-GP) had pro-apoptotic effects on human gastric carcinoma cells. By SDS-PAGE, we confirmed that C. fulvescens extract contained a glycoprotein. Using H33342 staining, we found that the Cf-GP caused cell death in a does-dependent manner, while an MTS assay showed decreased cellular viability due to induction of apoptosis. To determine the effect of Cf-GP on apoptosis-related cellular events, cells were treated with Cf-GP and the expression of several apoptosis-related protein was determined by Western blotting. Our results indicate that Cf-GP activated both a caspase cascade and PARP, which is a substrate of caspase-3, caspase-8 and the Bcl-2 family proteins. In addition, we assessed caspase-3, and -8 activation and annexin V staining. Our results revealed a cell cycle arrest, itself leading to an increased percentage of sub-G1 cells. Our findings indicate that Cf-GP may be a source of bio-functional material with therapeutic effects on human gastrointestinal cancer.

• 한국응용과학기술학회지
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• 제25권4호
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• pp.503-510
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• 2008

This research is related to the process of refining the raw material, industrial 2-propanone to the 2-propanone of the electronic grade. With this view, the high purity of 2-propanone was obtained through the complex preprocessing(physical adsorption method), distillation process and membrane-filtration of distillate. Impurities were identified by GC and UV, and then we assayed the water content in 2-propanone passing adsorption step made of activated carbon and Zeolite 4A. Furthermore, the distillation was performed with the packed column distillation apparatus to eliminate impurities such as acetaldehyde. Particulates were removed by reduced-pressure filtration through $0.5{\mu}m$ membrane filter and the number of the particulates was measured by particulate counter to confirm the removal of impure particles.

• 한국재료학회지
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• 제25권2호
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• pp.81-89
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• 2015

A strain-gradient crystal plasticity constitutive model was developed in order to predict the Hall-Petch behavior of a Ni-base polycrystalline superalloy. The constitutive model involves statistically stored dislocation and geometrically necessary dislocation densities, which were incorporated into the Bailey-Hirsch type flow stress equation with six strength interaction coefficients. A strain-gradient term (called slip-system lattice incompatibility) developed by Acharya was used to calculate the geometrically necessary dislocation density. The description of Kocks-Argon-Ashby type thermally activated strain rate was also used to represent the shear rate of an individual slip system. The constitutive model was implemented in a user material subroutine for crystal plasticity finite element method simulations. The grain size dependence of the flow stress (viz., the Hall-Petch behavior) was predicted for a Ni-base polycrystalline superalloy NIMONIC PE16. Simulation results showed that the present constitutive model fairly reasonably predicts 0.2%-offset yield stresses in a limited range of the grain size.

• Tribology and Lubricants
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• 제4권1호
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• pp.56-68
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• 1988

The wear resistance of P-bronze which is widely used as worm gear material was investigated. In order 1o study the effect of additional elements on the wear resistance of Pbronze, the applied load and sliding time were selected as variables, and SCM4, were used as against metal. The addition of Fe improve wear resistance, for it precipities hard Fe$_3$ P phase and the work hardening coefficients are lowered due to decreasing solubility of P. When Fe is added in conventional P-bronze, the alloy is rather sliding than forming wear debris by frictional force during wear test. Experimental results indicated that the wear mechanisms for P-bronze are mainly consisted of abrasive wear due to Beilby layer forming mechanism and adhesive wear due to thermally activated wear mechanism. Moreover, the weight loss is decreased in accordance with increasing load and time. However the rate of wear loss is decreased as the sliding time is increased.

• 한국물환경학회지
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• 제20권4호
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• 펄프종이기술
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• 제39권2호
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• pp.9-16
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• 2007

Biological treatment using the activated sludge method and biofilm process has been developed for paper wastewater treatment. It is known that a water treatment using biofilm process has a high efficiency be-cause a great deal of microorganism could adhere to media. It is also known that various plastics such as polyurethane and polyethylene have been used as the media. In this study polyethylene was used as a media and rice straw an additive agent to improve porous and hydrophilic properties of the media for waste water treatment. Porosity and hydrophilic characteristics of polyethylene was increased as rice straw was added to polyethylene. Paper wastewater was then treated with newly developed environment materials. Rice straw showed excellent results in waste water treatment in various media. This environmentally friendly material prepared by polyethylene and rice straw could show similar results to those of a commercial porous polyurethane foam in wastewater treatment.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.85.1-85.1
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• 2011

In this study, Grafoil$^{TM}$ which has comparable electric resistance and chemical stability but is flexible, fragile, and cheap material was adopted as bipolar plates for proton exchange membrane fuel cell(PEMFC) having only one straight line flow channel. Because of its flexibility, pressurizations of cell with various pressures showed different operating characteristics compared to ordinary graphite-used PEMFC. While performances of both cells decreased as these were pressurized, investigation of ohmic and faradaic resistance by electrochemical impedance measurement indicated different tendency of change. Ohmic resistance of graphite-used cell increased with increasing pressure, which is reversed in Grafoil$^{TM}$-used cell. It is speculated that effective chemical reaction area is decreased with increasing pressure in case of graphite-used one, but because of flexible property of Grafoil$^{TM}$, gas diffusion layer in Grafoil$^{TM}$-used cell was well-activated. Different rate of change of faradaic resistances in both cells support this supposition. However, although optimum point of pressurization is found, it is required to investigate other operating conditions because of low performance compared to graphite-used cell.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.48-54
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• 2002

Since photocatalysts are activated by lights of UV wavelengths, plasma is alternatively used as a light source for a photocatalytic reactor. Light intensity generated by plasma is proportional to the surface area of catalytic material, and this, in many practical applications, is prescribed by the geometry of a plasma generator. Thus, it is crucial to increase the surface area far sufficient light intensity for photocatalytic reaction. For example, in a pack-bed type reactor, multitudes of beads are used as a substrate in order to increase the surface area. Honeycomb monolith type substrate, which has very good surface area to volume ratio, has been difficult to apply plasma as a light source due to the fact that light penetration depth through the honeycomb monolith was too short to cover sufficient area, thus resulting in poor intensity for photocatalytic reaction. In this study, nonthermal plasma generation through a photocatalytic reactor of honeycomb monolith substrate is investigated to lengthen this short penetration depth. The ceramic honeycomb monolith substrate used in this study has the same length as a three way catalyst used fur automotive applications, and it is shown that sufficient light intensity for photocatalytic reaction can also be obtained with honeycomb monolith type reactor.