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        검색결과 129

        61.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The EMI shield material with narrow width has some deficiencies in shielding capability and this deficiencies are caused by the inconsistent relationship between the inductance and temperature after heat treatment. This study is performed to develop a nano crystal magnetization heat treatment process technology and design a EMI shielding material with wide width up to 350mm. As a result, the performance of the developed wide EMI shield material satisfies all the objects of this study such as the inductance, thickness, permeability, ribbon productivity, lamination productivity. Also, we find that this wide EMI shield material can be used effectively for the EMI shield room, large medical equipment and so on.
        4,000원
        62.
        2015.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the lower power consumption FET-DC contactor for golf cart and low speed electric vehicle has been designed and developed. Also, the author carrying out many measurements and tests such as an electric power consumption, current consumption, calorific value, size, volume and weight of the DC contactor for the various cases. As a result, the author found that a prototype of the lower power consumption FET-DC contactor can not only reduce calorific value, size, volume and weight but also improve an electric power and current consumption.
        4,000원
        63.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The functional wood plastic composite(WPC) is one of the noted materials for landscape architecture and residential construction. Iron band, embossing and drain holes are improve the strength and skid resistance of the WPC. In this study, we had developed an automatic manufacturing system for the functional WPC that has vertical pattern embossing and drain holes. The system is consist of an automatic vertical pattern embossing device, multi-spindle drilling M/C, sanding device, inspection equipment, and some facilities developed in the previous research. The performance tests on the several functional items of the system and manufactured WPC represented satisfactory values except the skid resistance and absorption thickness expansion rate.
        4,000원
        64.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Multi-layered metal sheet for electromagnetic interference(EMI) shielding purpose has been designed using metal sheet, PET & DST stacking and laminating technology. Also, an automatic manufacturing system is developed. This metal sheet with multi-layered structure is an effective shield against EMI that can not shield completely by single metal sheet. And the developed automatic manufacturing system can stack and lamination thin metal sheets without any wrinkles.
        4,000원
        65.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Traditionally the powder polymer has been used in the sewage sludge treatment and water purifying plants. The powder polymer, however, has several problems such as bad working condition by dispersed powder and unstable operation of dehydrator by a lump of undissolved polymer. In this study, high accuracy automatic dissolving system for emulsion polymer is developed to reduce the cost of facility and is suitable for unit-process automation. This system is consist of the emulsion polymer storage tank, polymer dissolving solution supply tank, mixing chamber, micom and mobile system, etc. Performance tests for the system such as the rated flow of flowmeter, quantity of the tube pump, solubility of the mixing chamber, accuracy of micom and mobile system have been performed. The performance of the prototype system satisfies all the objects of this study.
        4,000원
        66.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effective use of disinfection and sterilization is important in preventing healthcare associated infections. Especially, multi-drug resistant organism and spore-forming bacteria are serious pathogens. Therefore, control of a nosocomial infection is emerging as a big problem. It is efficiently necessary to eliminate the pathogen. In this study, the components of sterilant were optimized. The optimized sterilant was applied for efficiency of sterilization using G. stearothermophilus E. coli, S. aureus as a standard microorganism. Our results were shown as follows : The decomposition or loss of potency of sterilant in small containers did not appeared for one month at ambient temperature. All of hydrogen peroxide 0.5%, peracetic acid 0.01%, and IPA 60% was effective for sterilization of E. coli, S. aureus using dilution method. Two kinds of sterilants(hydrogen peroxide 2%+peracetic acid 0.1%+IPA 0.5%, hydrogen peroxide 4%+peracetic acid 0.06%+IPA 1%) were bacteriocidal(> 6 log reduction). Microorganisms(E. coli, S. aureus) which treated with these sterilants for 2min were not grown in LB broth at 7 days culture. The gas plasma system for sterilization was applied. The sterilant solution(hydrogen peroxide 20%+IPA 5%) was vaporized in the sterilization chamber. The vaporized sterilant was bacteriocidal and sporocidal(> 6 log reduction) using G. stearothermophilus E. coli, S. aureus as biological indicators
        4,000원
        67.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The adoption of scroll type air compressor is gradually increased in the automotive/residential air-conditioner and clean air compressor, and the most of critical components of the scroll are made of aluminum to reduce the friction and weight. Many studies for the surface treatment of the aluminum have been performed to reduce the friction between the components. In the preceding research, we suggested the most appropriate combination of the solid lubricant. In this study, we coated the part of fixed or orbiting scroll wrap with the solid lubricant that suggested in the preceding research, and then have performed analysis of performance characteristics for the part. As a result, we could obtain the 7.66μm of the coating thickness, Ra 0.8μm of the surface roughness and 0.088 of the friction coefficient. These represent the satisfactory capability of the suggested solid lubricant for the scroll type air compressor.
        4,000원
        68.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In our country, the number of coffee shops has steadily increased, reaching approximately 15,000 in 2013 from 1,254 in 2006. Adding to increase of coffee shops, customers' preference of roasted beans and extraction to ready-made coffee or instant coffee has lead to rapid expansion of roasted coffee market. In this study, the semi-rotating fluidized bed roaster prototype to reduce LPG consumption of the existing 60kg class large rotating fluidized bed roaster has been designed and retrofitted. In addition to the roaster prototype, processing system consist of bean automatic feeding equipment, debris sorting device, cooling device, cyclone collector, main control system etc. was developed. Also, the authors carrying out many measurements and tests such as LPG consumption, bean transfer time, debris sorting rate, cooling time and temperature, chaff collection rate for the various cases. As a result, the authors found that the semi-rotating fluidized bed roaster prototype can not only reduce LPG consumption, green bean transfer time, cooling time and temperature but also improve debris sorting rate, chaff collection rate of during coffee roasting
        4,000원
        69.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Automatic continuous manufacturing system is necessary to raise the productivity and strengthen the competitiveness in the wire manufacturing. The automatic wire cutting technology is an important element to link various processes and it is crucial technology to obtain high accuracy and quality of the wire. This study was performed to develop an automatic stainless steel wire cutting equipment that is consist of the first and second cutting equipments besides related devices to cut stainless steel wire. This wire cutting equipment can cut wire with high accuracy, and it can prevent sintering and discoloration
        4,000원
        70.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The coating of solid lubricant on the part of fixed or orbiting scroll wrap in a scroll compressor can not only reduce friction loss, noise & vibration and time cost for surface finishing but also improve efficiency and performance of the compressor. In this study, we found the most appropriate combination of the solid lubricant by carrying out many measurements and tests such as coefficient of friction, surface structure, the coating thickness and surface roughness for the various cases. We have come to conclusion that the most appropriate solid lubricant can be obtained by adding WS2 3% to Base(SM 3901) without any solvent and filler.
        4,000원
        73.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Wire manufacturing system is consist of several parts performing such as feeding, drawing, straightening, heat treatment, surface finish and winding. Drawing and straightening processes are repetitive tasks and the most of the them are performed discretely. In this study, automatic manufacturing system for medium fine straight wire has been developed. The developed system is operated with continuous processes, so decrease the time cost and increase product quality
        4,000원
        74.
        2014.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ultra thin sheet for electromagnetic interference(EMI) shielding purpose has been designed using base metal, PET & DST sheet stacking technology. Also, an automatic manufacturing system is developed. This ultra thin EMI shielding sheet is an effective shield against low frequency(~300kHz) EMI that can not shield completely by the existing EMI shielding sheet. And the developed automatic manufacturing system can stack ultra thin shielding sheet without any wrinkles.
        4,000원
        75.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe-TiC composite was fabricated from Fe and TiC powders by high-energy milling and subsequent spark- plasma sintering. The microstructure, particle size and phase of Fe-TiC composite powders were investigated by field emission scanning electron microscopy and X-ray diffraction to evaluate the effect of milling conditions on the size and distribution of TiC particles in Fe matrix. TiC particle size decreased with milling time. The average TiC particle size of 38 nm was obtained after 60 minutes of milling at 1000 rpm. Prepared Fe-TiC powder mixture was densified by spark- plasma sintering. Sintered Fe-TiC compacts showed a relative density of 91.7~96.2%. The average TiC particle size of 150 nm was observed from the FE-SEM image. The microstructure, densification behavior, Vickers hardness, and frac- ture toughness of Fe-TiC sintered compact were investigated.
        4,000원
        76.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the ‘background’ task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using ‘background’ task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.
        4,000원
        78.
        2012.06 구독 인증기관·개인회원 무료
        The reactive oxygen species (ROS) generated during the somatic cell transfer nuclear (SCNT) procedures may cause the mitochondrial dysfunction and DNA damage, which may result in restricts the reprogramming of SCNT embryos and play a key direct role in apoptosis. The present study was conducted to investigate the effect of antioxidant treatment during the SCNT procedures on the inhibition of mitochondria and DNA damages in bovine SCNT embryos. The reconstituted oocytes were treated with antioxidants of 25 μM β-mercaptoethanol (β-ME) or 50 μM vitamin C (Vit. C) during the SCNT procedures. In vitro fertilization (IVF) was performed for controls. Mitochondrial morphology and membrane potential (ΔΨ) were evaluated by staining the embryos with MitoTracker Red or JC-1. Apoptosis was analyzed by Caspase-3 activity assay and TUNEL assay, and DNA fragmentation was measured by comet assay at the zygote stage. Mitochondrial morphology of non-treated SCNT embryos was diffused within cytoplasm without forming clumps, while the IVF embryos and antioxidant treated SCNT embryos were formed clumps. The ΔΨ of β-ME (1.3±0.1, red/green) and Vit. C-treated (1.4±0.2, red/green) SCNT embryos were significantly higher (p<0.05) than that of non-treated SCNT embryos (0.9±0.1, red/ green), which similar to that of IVF embryos (1.3±0.1, red/green). Caspase-3 activity was not difference among the groups. TUNEL assay also revealed that little apoptosis was occurred in SCNT embryos as well as IVF embryos regardless of antioxidant treatment. Comet tail lengths of β-ME and Vit. C-treated SCNT embryos (337.8±23.5 μm and 318.7 ±27.0 μm, respectively) were shorter than that of non-treated SCNT embryos (397.4± 21.4 μm) and similar to IVF embryos (323.3±10.6 μm). These results suggest that antioxidant treatment during SCNT procedures can inhibit the mitochondrial and DNA damages of bovine SCNT embryos.
        79.
        2012.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, the silver nanoparticles have been synthesized by electrical explosion of wire in three liquid mediums: deionized water (DIW), polyvinylpyrrolidone (PVP) and sodium dodecyl benzene sulfonate (SDBS) solutions. Absorption in the UV-visible region of these suspensions was measured in the range of 300-800 nm. A surface plasmon peak was observed at ~400 nm in all suspensions in measured wavelength range. Particle size was analyzed by transmission electron microscope. It showed that the particles had nearly spherical shape in all samples. The average particle sizes prepared in DIW, PVP and SDBS solution were 37, 31 and 27 nm, respectively. Stability of the suspensions was estimated by multiple light scattering method. The presence of PVP and SDBS surfactants in the exploding medium resulted in enhanced stability of the silver suspensions.
        4,000원
        80.
        2011.10 구독 인증기관·개인회원 무료
        Cell transplantation therapy using adult stem cells has recently been identified as a potential treatment for spinal cord injury (SCI). But, recovery after traumatic SCI is very limited. As dogs are physiologically much more similar to human compared with other traditional mammalian models in disease presentation and clinical responses, a number of researches demonstrated canis familiaris is a suitable model for human diseases. This study investigated the effect of transplantation of canine Mesenchymal Stem Cells (cMSC) and neural-induced cMSC (nMSC) to understand how these cells improve neurological function in canine SCI model. The differentiation of cMSC into neural precursor cells was induced in dulbecco’s modified eagle’s medium supplemented with N2-supplement, dibutyryl cyclic adenosine monophosphate, and butylated hydroxyanisole. SCI was induced between T1 and T2 by surgical hemi-section in adult dogs, and then assigned to two groups according to the applied cell types (cMSC vs nMSC). Pelleted cMSC or nMSC were transplanted directly into the injured site after SCI, respectively. Analysis of motor function after transplantation was evaluated by modified Olby score. Magnetic resonance imaging (MRI), histological and immunohistichemical analysis were also performed. Functional recovery in group of cMSC was increasing gradually after transplantation and was higher than nMSC. In MRI, we could not confirm any difference between the cMSC and nMSC experimental groups. Immunohistochemically, beta3-tubuline and nestin were observed in injury site of two experimental groups with the expression level close to non-injured groups. Transplantation of mesenchymal stem cells could promote neuronal reconstruction and repair motor function in SCI. These showed mesenchymal stem cells could be a great candidate as a therapeutic tools in degeneration disease, and dogs could be used to explore human regenerative medicine as a promising animal model. This research was supported by iPET (Grants 110056032CG000), Ministry for Food, Agriculture, Forestry and Fisheries, Republic of Korea.
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