• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.75-83
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• 2010

Laminated composite plates have shown their superiority over metals in applications requiring high specific strength, high specific modulus, and so on. Therefore, they have used in various industry. However, they have poor resistance to impact compared to typical metal materials. So, many researchers have investigated about impact behavior of laminated composite plate. To investigate impact behavior of laminated composite plate, we have to calculate contact force between impactor and laminated composite plate at the first. Impactor's equation of motion, plate's equation of motion and correlations for indentation were solved to know the contact force at the same time. In this study, low velocity impact behavior of composite plate was investigated using the finite element program which is involved the classical Hertzian law, Sun's law and Sun & Yang's experimental law and Sun & Tan's experimental law considering the stacking method.

• Korean Journal of Materials Research
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• v.19 no.4
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• pp.224-227
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• 2009

Nanofabrication is an essential process throughout industry. Technologies that produce general nanofabrication, such as e-beam lithography, dip-pen lithography, DUV lithography, immersion lithography, and laser interference lithography, have drawbacks including complicated processes, low throughput, and high costs, whereas nano-transfer printing (nTP) is inexpensive, simple, and can produce patterns on non-plane substrates and multilayer structures. In general nTP, the coherency of gold-deposited stamps is strengthened by using SAM treatment on substrates, so the gold patterns are transferred from stamps to substrates. However, it is hard to apply to transfer other metallic materials, and the existing nTP process requires a complicated surface treatment. Therefore, it is necessary to simplify the nTP technology to obtain an easy and simple method for fabricating metal patterns. In this paper, asnTP process with poly vinyl alcohol (PVA) mold was proposed without any chemical treatment. At first, a PVA mold was duplicated from the master mold. Then, a Mo layer, with a thickness of 20 nm, was deposited on the PVA mold. The Mo deposited PVA mold was put on the Si wafer substrate, and nTP process progressed. After the nTP process, the PVA mold was removed using DI water, and transferred Mo nano patterns were characterized by a Scanning electron micrograph (SEM) and Energy Dispersive spectroscopy (EDS).

• Journal of Fashion Business
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• v.22 no.1
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• pp.100-113
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• 2018

From the late 17th to the early 18th century, Europeans were strongly intrigued by products from the East. Therefore, several countries like England, France, and Netherlands formed the 'East India Company' to pursue trade. First, European markets rapidly responded to this desire for exoticism by importing goods; then, they produced imitation Oriental goods. Finally, they made stylistically advanced exotic merchandise from the perspectives of European. In terms of the textile industry, this trend was expressed in the pattern design of silk, or the so called 'bizarre silk.' In this paper, bizarre silk patterns were scrutinized based on a digital archive of museums, catalogues of museums, portal sites, and the literature. The bizarre silk patterns were analyzed then classified into six categories: pseudo-Oriental plant pattern, pattern mingled with architectural motifs, pattern of juxtaposed with Oriental goods, abstract pattern, exuberant pattern with metal threads, and semi-naturalistic pattern. These patterns were characterized according to the following features: strangely large exotic floral patterns were undulating and asymmetrical; exotic foliage and flowers were sometimes mixed with architectural motifs or Oriental goods to easily show the Oriental influence; motifs of bizarre silk patterns were abstractly stylized; bizarre silk patterns became luxurious once more like the Baroque period; finally, floral patterns became more natural, and still exotic motifs remained in the background to maintain the bizarre silk features. These bizarre silk patterns evolved from the viewpoints of Europeans through acceptance stage, compound stage, and confluent stage.

• Journal of Environmental Science International
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• v.21 no.3
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• pp.369-375
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• 2012

We investigated usefulness of chicken feather as bioadsorbent for removal of hexavalent chromium[Cr(VI)] and oil from aqueous solution. Chicken feather was chemically treated with DTPA, EDTA, NaOH and SDS, respectively. Among them, EDTA was the most effective in adsorbing Cr(VI). Cr(VI) uptake by chicken feather was increased with decreasing pH; the highest Cr(VI) uptake was observed at pH 2.0. By increasing Cr(VI) concentration, Cr(VI) uptake was increased, and maximum Cr(VI) uptake was 0.34 mmol/g. Cr(VI) adsorption by chicken feather was well described by Freundlich isotherm than Langmuir isotherm and Freundlich constant(1/n) was 0.476. As the concentration of chicken feather was increased, Cr (VI) removal efficiency was increased but Cr(VI) uptake was decreased. Most of Cr(VI) was adsorbed at early reaction stage(1 h) and adsorption equilibrium was established at 5 h. On the other hand, chicken feather adsorbed effectively oils including bunker-A and bunker-C. In conclusion, our results suggest that chicken feather waste could be used to remove heavy metal and oil; it is a potential candidate for biosorption material.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.259-264
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• 2005

The copper clad steel wire is used extensively as lead wires of electronic components such as capacitors, diodes and glass sealing lamp because the wire combines the strength and low thermal expansion characteristic of Fe-Ni steel with the conductivity and corrosion resistance of copper. In order to fabricate the copper clad steel wire, several processes including electro-plating, tubecladding extrusion process and dip forming process have been introduced and applied. The electroplating process for the production of copper clad steel wire shows poor productivity and induces environmental load generation such as electroplating solution. The dip forming process is suitable to mass production of copper clad steel such as trolley wire. and need expensive manufacturing facilities. The present paper describes the improvement of the conventional continuous casting process to fabricate copper clad steel wire, which its core metal is low thermal expansion Fe-Ni alloy and its sheath material is copper. In particular, the formation of intermetallic compound at interface between core and sheath was investigated in order to introduce optimum continuous casting process parameter for fabrication of copper clad steel wire with higher electrical conductivity. The mechanical strength of copper clad steel wire was also investigated through wiredrawing process with of 95% in total reduction ratio.

• Resources Recycling
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• v.4 no.3
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• pp.2-9
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• 1995

The rccoverg and separation pracess of nikcl, vanadium and molybdenum from spent dcsulfilrizing catalyst ofpetrochemical rndustries was studied. Tnis process was canied out wet process which is consist of roasting, ammonialeaching and solve111 exDaction techniqcs. The metal ions of NI, V and Mo as vduable compollents were treated byroasting them a1 low lernperatuc, 400$^{\circ}$C in first dep, and then dlssah'ed nu1 at 80$^{\circ}$C wlth ammonium cabonate mlulion.Aftcr cooling them a1 room tempertaure, vanadium wa rccavered from mathcr iiquur in thc f n m of precipitate, sodiumvanadales The Secand slep, roasting the catalyst which is added sodium carbonate ul IOOO"C, was employed. Leachingwith distilled ~ a l e rga ve a iwo phase resultant, solutio~c~a ntaning Ni, V and Mo and solid residue containing sibca,alurmniu~n and iron. A solvcnt exlclction technique uslng vvriuus extractanls, MSP-8, TOIUC, LIX64Pi was eflecnve farthc extraclion and scparation ol thrcc mcfals from thc ammonical 11qou1 thc ammonical 11qou1.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.124-125
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• 2007

The composites were fabricated $\beta$-SiC and $TiB_2$ powders with the liquid forming additives of 8, 12, 16[wt%] $Al_2O_3+Y_2O_3$ as a sintering aid by pressureless annealing at $1,650[^{\circ}C]$ for 4 hours. Reactions between SiC and transition metal $TiB_2$ were not observed in the microstructure and the phase analysis of the pressureless annealed SiC-$TiB_2$ electroconductive ceramic composites. The relative density, the flexural strength, the Young's modulus and the Vicker's hardness showed the highest value of 82.29[%], 189.5[MPa], 54.60 [GPa] and 2.84[GPa] for SiC-$TiB_2$ composites added with 16[wt%] $Al_2O_3+Y_2O_3$ additives at room temperature. The relative density of SiC-$TiB_2$ composites was lowered due to gaseous products of the result of reaction between SiC and $Al_2O_3+Y_2O_3$. The electrical resistivity showed the lowest value of 0.012[${\Omega}{\cdot}cm$] for 16[wt%] at 25[$^{\circ}C$]. The electrical resistivity was all negative temperature coefficient resistance (NTCR) in the temperature ranges from 25[$^{\circ}C$] to 700[$^{\circ}C$].

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.9
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• pp.5789-5794
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• 2015

Recently, thin and light-weight production technologies are needed in IT industry in accordance with increase of the smart phones and mobile PC products. In order to make light and high rigidity products, engineering plastic and aluminum materials are frequently used in products appearance and frame hat support structure. Especially aluminum extrusion and CNC Brick processes are widely used for high strength and high rigidity technology. But extrusion method has constraints to apply exterior design and CNC Brick process has relatively high production cost and low speed of manufacturing. In this research, a new process method is introduced in order to reduce material cost and to improve manufacturing speed dramatically. Plate forging process means basically that thickening of local wall area thickness after deform exterior shape by deep drawing and bending process. Therefore, it is possible to minimize the waste of material and the manufacturing time. In this study the process of plate forging is designed using finite element program AFDEX-2D and the thickness and the width of initial deformed blank. And it is verified as a sample which is a part of laptop developed through the proposed plate forging method.

• Journal of Surface Science and Engineering
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• v.34 no.1
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• pp.10-16
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• 2001

Recently plasma etching research has been focused on the metal surfaces in the nuclear industry. In this study, surface etching reaction of metallic Co and Mo, principal contaminants in the spent nuclear components, in CF$_4$/O$_2$, gas plasma has been experimentally investigated to look into the applicability and the effectiveness of the technique for the surface decontamination. Experimental variables are $CF_4$/$O_2$ ratio and substrate temperature between 29$0^{\circ}C$ and 38$0^{\circ}C$. Experimental results Show that the optimum gas composition is 80%CF$_4$-20%$O_2$ and the metallic Co and Mo are etched out well enough in the temperatures range. Cobalt starts to be etched above $350^{\circ}C$ and the etching rate increases with increasing substrate temperature. Maximum rate achieved at 38$0^{\circ}C$ under 220 W r.f. plasma power is 0.06 $\mu\textrm{m}$/min. On the other hand, the metallic Mo is etched easily even at low temperature and the reaction rate drastically increases as the substrate temperature goes up. Highest rate obtained under the same conditions is $1.9\mu\textrm{m}$/min. OES (Optical Emission Spectroscopy) analysis reveals that the intensities of F atom and CO molecule reach maximum at the optimum gas composition, which demonstrates that the principal reaction mechanism is fluorination and/or carbonyl reaction. It is confirmed, therefore, that dry processing technique using reactive plasma is quite feasible and applicable for the decontamination of surface-contaminated parts or equipments.

• Resources Recycling
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• v.1 no.1
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• pp.44-50
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• 1992

The $\alpha$-FeOOH powders were prepared by allkaline and acidic method on the small scale plant from the waste pickling liquor of iron. $\alpha$-FeOOH, $\alpha-Fe_2O_3$, $Fe_3O_4$ and ${\gamma}-Fe_2O_3$ powders were examined by TEM, SEM, TG-DTA, X-ray diffraction, VSM and chemical analysis. The results obtained from the experiment could be summerized as follows : the reaction time for the preparation of $\alpha$-FeOOH was observed to be smaller in the case of alkaline method and the products was acicular with the size of about $0.5\mu\textrm{m}$. The color of $\alpha-FeOOH and $\alpha-Fe_2O_3$was lovely yellow and red, respectively. The magnetic properties of $Fe_3O_4$ obtained by the reduction of $\alpha-Fe_2O_3$in the $H_2$ atomosphere at $370^{\circ}C$ for 1 hour showed 367(Oe) and 82.7(emu/g).