• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.148-157
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• 1993

A study was conducted to evaluate the effect of enamel coating on boat hull drag. The results were compared with drag required for varnished uncoated boats. Models of rice barge and fishing boat were used in this study. The speed range of 0.6 to 1.5㎧ at different loads varying from 6 to 9 kg for rice barge and 4.6 to 6.4kg for fishing boats were used during testing. The total weight of the coated and uncoated boats were kept the same. It was observed that the drag force required by the coated boats was less than identical uncoated ones at all speeds and loads. For both uncoated and coated the drag required increased with speed. The maximum recorded reductions in drag were 26% for the rice barge and 28% for the fishing boat model.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.9-15
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• 2020

Carbon fiber reinforced plastic (CFRP) is a composite material useful in the aerospace and automotive industries because of its light weight and high strength. In this study, side milling tests were carried out using AlCrN, diamond-like carbon (DLC), and diamond-coated end mills. Additionally, a comparison study according to the cobalt content was conducted. Thus, tool wear and surface quality were examined and the influences of using coating and a certain material type were analyzed. The surface roughness of the machined surface was measured. Microscope observations revealed that the CFRP fiber at the machined surface was not damaged even at a cutting distance of 3,000 mm. Therefore, this study showed that the diamond-coated end mill containing 6% cobalt is appropriate for milling CFRP.

• Journal of Environmental Health Sciences
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• v.24 no.2
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• pp.104-109
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• 1998

The objective of this study was to examine the effect of polymer coating on the initial microorganism attachment and the biofilm growth. Such as nonion(polyacrylamine), anion(CMC-Na) and cation polymer coagulant(chitosan and PEI) were used for coating material of the support carrier(acryl plate). When polymer coagulant was coated with 5, 10, 20, 35, 50, 100 and 200 mg/l on the surface of acryl plate, initial microorganism attachment increased and optimum concentration for the attachment was 35 mg/l. Biofilm growth experiments were conducted with the substrate loading of 12.7gSCOD/$m^2\cdot$ day using RBC. The polymer coagulants such as CMC-Na, polyacrylamide, PEI and chitosan coating on the acryl plate facilitated the biofilm growth of microorganisms. Until the biofilm dry weight grows up to 0. 0038g/cm$^2$, biofilm growth on the plate coated with cation polymer like chitosan was better than that on the coated plate of nonion(polyacrylamine), anion(CMC-Na) polymer coagulant.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.2
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• pp.145-150
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• 2011

There is problem to reduce the car body weight for improving fuel consumption and $CO_2$ generation. As one of the solution, the multi material car body concept using aluminum alloys and high strength steels is proposed recently. Therefore, new welding processes by which these dissimilar material can be joined in high reliability and productivity are demanded. Laser spot welding was developed for joining of dissimilar metals. In the present work, Laser spot welding of zinc coated steel and aluminum alloy was investigated, and the process parameters were studied. Otherwise, the influences of process parameters on the weldability, the formation of intermetallic compound layer and the mechanical properties have been investigated. When intermetallic compound layer thickness was more than 1mm, specimen was failure in the interface.

• Journal of Industrial Technology
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• v.32 no.A
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• pp.29-33
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• 2012

We demonstrated the viability of fully microfabricating SWCNT(single-wall carbon nanotube) film strain sensors for force and weight sensing. Our spray-deposited SWCNT film strain sensors showed good linearity over a range from 0 to 400 microstrain, and much higher sensitivity compared to commercial metal foil-type gauges. The number of grids and the thickness of the SWCNT film were found to have a significant effect on the strain sensing properties of the SWCNT film gauges. A strain sensing methode for the CNT-based strain gauges was also investigated using a binocular type beam load cells. Preliminary results indicate that the microfabrication method shown here is promising for developing a commercial strain gauge using a spray-coated SWCNT thin film. In the near future, various studies will be performed to further enhance the properties of the spray-coated SWCNT film strain sensors.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.60-68
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• 1997

To develop paper coating technology for preventing print mottling, which is recognized as the most common printing problems in using coated papers, ink absorption properties of various coated papers were examined by employing K 8T N and Croda ink absorption tests. The influences of pigment compositions, coat weights and drying methods on these ink absorption properties were examined, and then the variations of ink absorption ratio were analyzed and discussed. It is demonstrated that the variation of Croda ink absorption ratio induced by coat weight variation can be utilized most succesfully to predict print mottling propensity of coating formulations. A systematic analysis approach was suggested that can be employed in the development of the most desirable coating color formulation to achieve target optical properties with the least print mottling.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.96-96
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• 2010

Monodispersed spherical silica-coated ceria nanoparticles were prepared through a sol-gel process using tetraethylorthosilicate (TEOS) and ceria fine particles. In this process, ceria fine particles were also prepared from cerium nitrate. The mean size of ceria particles was 300nm. Silica nanoparticles with narrow particle size distribution were prepared by controlled hydrolysis of TEOS solution. The silica sols were obtained by peptization, the process of redispersing a coagulated colloid, and were coated on ceria particles by the control of the weight ratio of silica/ceria and the pH of the mixture in aqueous solution. The morphologies of particles were characterized with scaning electron microscopy(SEM), transmission electron microscopy(TEM) and atomic force microscopy(AFM). The coating thickness of silica particles obtained by using this method was controlled in the range of 30 - 70nm.

• Journal of the Korean institute of surface engineering
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• v.15 no.4
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• pp.208-217
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• 1982

To study the effect of TiC coating on weight change, microhardness, wear and heat - resistance of TiC layer, chemical vapour deposition on the various substrates has been carried out with the gaseous mixture of TiCl4, toluene, and H2 in the temperature range of 900 - 1000$^{\circ}C$. The results obtained are as follows ; (1) There is a limited value of carrier and reductant H2 gas flow rate, above which deteriorate effect on the TiC depoition arises (2) Increased thickness of TiC layer was resulted with increasing temperature and time. Better deposition was obtained with stainless steels and the best results were introduced by cobalt coating of substrates. (3) Wear resistance of the TiC coated specimen improved markedly. Heat resistivity of the coated steel showed excellent result, whereas the coated stainless Steels were infer-ior to the substrate.

• Food Science and Preservation
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• v.4 no.3
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• pp.251-258
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• 1997

The quality changes of strawberries packaged using low density polyethylene (LDPE) film filled with 3% silver-coated ceramic (WC30) and filled with it and 0.1% chitin (CWC) were investigated during storage at 2$0^{\circ}C$ for 5 days. In gas composition within film bag, CWC and WC30 kept higher CO2 concentration than LDPE without silver-coated ceramic and chitin (CO) did during 5 day storage. The weight loss of strawberries during storage was the smallest in WC30 and the largest in CWC in 5 days. Hardness of strawberries was the highest in WC30 and the lowest in CO during 5 day storage. pH of strwberries was increased a little until 1 day and was not changed after 1 day storage, and soluble solid content was not changed during storage. Vitamin C content was decreased significantly until 2 day storage and decreased a little after 2 days. There is no differences in the change of vitamin C content among the packaging materials. In color measurement, lightness was the highest in WC 30 and in sensory evaluation, all characteristics also had the highest scores in WC30. In conclusion, better quality of straberries was shown in WC30 than in CWC and CO during storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.4
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• pp.214-222
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• 1998

These experiments were conducted to investigate water uptake, electrical conductivity, germination percentage, seedling growth, and seedling establishment rate in direct seeding cultivation of rice. The rice seeds of six japonica type varieties were coated with 12 kinds of polymers in a standard concentration of 0.2% using seed coating machine. The water absorption of the polymer-coated seeds under saturation conditions was not different among varieties, and was the highest in kulcel, maltrin, and waterlock on the polymer-coated seeds. The electrical conductivity with waterlock (55.0 $\mu scm^{-1}g^{-1}$) was higher than the control plot (45.6 $\mu scm^{-1}g^{-1}$) and other treatments. The germination of the polymer-coated seeds was 95.9% at control plot, 92.7% at low temperature and 35.7% at high temperature. The total dry weight of seed decreased in the order of low temperature, control plot, and high temperature, and was effective in pvp (polyvinyl pyrrolidone), opadry, and sacrust. The seedling establishment rate in direct seeding cultivation ranged from 74.9 to 81.0% in flooded paddy surface, and ranged from 64.7 to 76.6% in dry paddy. In both cases, it decreased in the order of early, medium and medium-late varieties, but was enhanced in daran 8600, sepirect, and sacrust. According to this study the recommended polymers for direct seeding cultivation of rice are daran 8600, sepirect, and sacrust.