• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.554-554
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• 2000

To improve mechanical properties of Cu-Al-Ni alloy by the grain refinement, Cu-Al-Ni SMA ribbons were fabricated by melt spinning apparatus. The variations of microstructure, mechanical properties and transformation characteristics with the condition of rapid solidification and annealing time-temperature were investigated in Cu-Al-Ni SMA ribbons. The ribbons fabricated by melt spinning obtained around 1.5nm in width and 50-60${\mu}{\textrm}{m}$ in thickness. With increasing wheel speed in order of 10m/s, 15m/s, 20m/s, 30m/s and 3m/s, the grain size was decreased in order of 10${\mu}{\textrm}{m}$, 6.25${\mu}{\textrm}{m}$, 5.5${\mu}{\textrm}{m}$, 3${\mu}{\textrm}{m}$ and 3${\mu}{\textrm}{m}$. $M_{s}$ and $A_{s}$ temperature were decreased with decreasing grain size. By X-ray diffraction test, ordered $\beta$$_1$ phase was observed in all the SMA ribbons and the volume friction of it was increased with increasing wheel speed. With increasing wheel speed, strain was increased from 4.2% to 5.8% and fracture mode has changed from mixture of intergranular and dimple fracture to mixture of fiber structure and dimple fracture. The grain size of ribbon heat-treated at $600^{\circ}C$ was increased with increasing time. In the heat-treated ribbons at 55$0^{\circ}C$, ${\gamma}$$_2$ phases were observed.d.d.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.165-173
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• 2003

As the cycling time of new products have become more and more short in recent years, the demand for lowering the cost and reducing the production time becomes stronger. In order for the demand, the rapid prototyping and rapid tooling technology have been used. It has been widely known that RP technology has advantages with fabricating 3-D object having a complicated geometric shape. RP products, however, have a limitation with applying to the real die and mold because soft materials such as resin, paper and wax has been mostly used in RP technology. So in this paper, the RP products have been copied to semi-metallic soft tools using the mixture of metal fillers and epoxy resin. In order to evaluate the effect of the fillers on the characteristics of semi-metallic soft tools, three fillers are used including commercial aluminum powder, cast iron powder recycled by machining chips, and aluminum short fiber made by self-excited vibration technique. Besides, in the case of aluminum powder, the change of characteristics of semi-metallic soft tools is also tested according to the volume fraction of the powder.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.527-534
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• 2014

Poroelastic analyses of fiber-reinforced composites were performed using image-based computational models. The section image of a porous matrix was analyzed in order to investigate the porosity, number of pores, and distribution of pores. The resolution, location, and size of the section image were considered to quantify the effective elastic modulus, poroelastic parameter, and strain energy density using the image-based computational models. The poroelastic parameter was calculated from the effective elastic modulus and pore pressure-induced strain. In addition, the results of the poroelastic analyses were verified through representative volume elements by simplifying various pore configurations and arrangements.

• Journal of KSNVE
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• v.9 no.5
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• pp.1019-1028
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• 1999

Free vibration characteristics of cantilevered laminated composite beams with a transverse non0propagating open carck are investigated. In the present analysis a special ply-angle distribution referred to as asymmetric stiffness configuration inducing the elastic coupling between chord-wise bending and extension is considered. The open crack is modelled as an equivalent rotational spring whose spring constant is calculated on the basis of fracture mechanics of composite material structures. Governing equations of a composite beam with a open crack are derived via Hamilton's Principle and Timoshenko beam theory encompassing transverse shear and rotary inertia effect. the effects of various parameters such as the ply angle, fiber volume fraction, crack depth, crack position and transverse shear on the free vibration characteristics of the beam with a crack is highlighted. The numerical results show that the natural frequencies obtained from Timoshenko beam theory are always lower than those from Euler beam theory. The presence of intrinsic cracks in anisotropic composite beams modifies the flexibility and in turn free vibration characteristics of the structures. It is revealed that non-destructive crack detection is possible by analyzing the free vibration responses of a cracked beam.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.5
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• pp.251-261
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• 2011

The changes in microstructure and texture during annealing were examined in a series of 0.015% C-1.5% Mn cold-rolled sheet steels with 0~0.5% Mo. Orientation distribution function data were calculated from the (110), (200), (211) pole figures determined on the rolled plane of cold-rolled and annealed steel sheets. Regardless of Mo content and annealing conditions, martensite volume fraction was less than 1.0%, not affecting the texture evolution. Textural change at the cooling stage after heating at $820^{\circ}C$ for 67 sec was not observed. Increasing the Mo content and annealing temperature markedly strengthened the intensities of ${\gamma}$-fiber texture, resulting in the increase in $r_m$ value. The desirable texture evolution for deep drawability in the 0.5% Mo steel may be mainly caused by the grain refining effect of Mo carbide in the hot-rolled steel sheet.

• Food Science and Preservation
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• v.8 no.4
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• pp.442-448
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• 2001

The citrus juice obtained from Jeju mandarines, Citru unshiu, was filtered to remove 20% of its original volume through the hollow fiber ultrafiltration systems equipped with various pore sizes of membranes. As the results of ultrafiltration, the contents of total acids, ascorbic acid, ascorbic acid, free sugars and neohesperidin in retentate showed the tendencies of gradual decreases with the increase of membrane pore sizes from 10K to 100K daltons, but tendencies were inverted when the membrane with 500k was used. The changes of color, soluble solids, total nitrogen, amino-nitrogen, naringin and hesperidin were not consistent with the membrane pore size. Considering all the data obtained using various pen sizes of membranes, the filtration system with NMWC 500K daltons was the most effective to produce citrus juices with hither quality.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.4
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• pp.643-650
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• 2015

The principal objective of this study was to evaluate the quality of Yukwa prepared with mulberry leaf (Morus alba Linne) powder. The moisture, crude protein, crude lipid, crude ash, dietary fiber, and rutin contents of used mulberry leaf powder were 6.65%, 19.50%, 3.26%, 18.24, 38.91 and 0.54%, respectively. The tested concentrations of mulberry leaf powder were 0, 3, 5, and 7%. The Yukwa were stored at $45^{\circ}C$ for 40 days. Yukwa dough prepared with mulberry leaf powder had a lower pH compared to the control group. As more mulberry leaf powder was added, the spread ratio, moisture content, and volume increased. As more mulberry leaf powder was added, L-value decreased while a and b values increased with increasing mulberry leaf powder content. The hardness of Yukwa made with 7% mulberry leaf powder was the highest among the samples. In the sensory tests, Yukwa with 5% mulberry leaf powder received the highest scores. The acid value and peroxide values were lower in Yukwa prepared with mulberry leaf powder than control. Yukwa prepared with mulberry leaf powder strongly inhibited oxidation of lipids. The thiobarbituric values were lower in Yukwa prepared with 5% mulberry leaf powder than in Yukwa prepared with 3% and 7% mulberry leaf powders and control Yukwa. These results suggest that mulberry leaf powder can be applied to Yukwa to achieve high quality and functionality.

• Culinary science and hospitality research
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• v.13 no.4
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• pp.269-278
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• 2007

The purpose of this study was to investigate the taste and quality of persimmon leaves cakes with different-ly added(0, 4, 8, 12, 16%) persimmon leaves powder. The findings of this study were as follows; First, the proximate composition contents of persimmon leaves powder were analyzed as composed of 6.30% moisture, 19.20% crude protein, 2.80% crude fat, 18.93% crude ash, and 35.91% dietary fiber. Second, the specific gravity of sponge cakes was significantly increased with the amount of persimmon leaves powder added. As added percentage of persimmon leaves powder increased, L and b values were decreased and the color value was increased. Third, specific loaf volume was decreased as the percentage of persimmon leaves powder added increased. There was no significant difference in terms of baking loss percentage. Fourth, hardness and gumminess was increased as the percentage of persimmon leaves powder added increased in terms of textural characteristics. There was no significant difference of cohesiveness and springiness among samples. Fifth, the group of eight percent persimmon leaves powder added has the highest in color, flavor, taste, texture, and overall acceptance in sensory evaluation results. In conclusion, the sample group with 8 percent persimmon leaves powder added gave the best taste and quality to sponge cakes in this study.

• Journal of the Korean Ceramic Society
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• v.34 no.7
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• pp.693-698
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• 1997

The refractive index and dispersion in the (100-x)(0.6CaO.0.4Al2O3).xSiO2(x=0~30) glasses were investigated. As the amount of SiO2 increased, the refractive index decreased. The change of refractive index was attributed to the change of the molar refraction rather than the molar volume. When the amount of SiO2 was smaller than 20 mol%, the average electronic transition energy gaps(E0) and the electronic oscillator strengths(Ed) were about 10.9($\pm$0.1) nd 18($\pm$0.5)eV, respectively. However E0 and Ed of the glass (CAS30) with 30 mol% SiO2 increased to 12.63 and 19.89eV, respectively. The similar results was observed in the variation of Abbe Number. Abbe number of the glass in the range of 0~20 mol% SiO2 was about 46 and that of CAS30 increased to 60. The zero-material dispersion wavelength({{{{ lambda }}0) of pure calcium aluminate glass was 1.8 ${\mu}{\textrm}{m}$. As the amount of SiO2 increased, the zero-material dispersion wavelength shifted to a shorter wavelength. {{{{ lambda }}0 of CAS30 was 1.5 ${\mu}{\textrm}{m}$, that is currently using for the optical telecommunication system.

• Journal of Arbitration Studies
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• v.16 no.3
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• pp.191-216
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• 2006

It has been talked about the responsibility of the South-North Korean e-market place(e-MP) collaboration project every you since 2003. However, the feasibility as the business has not been dealt with in detail due to the uncertain environment as well as the complicated procedures of the project. The research focuses on the workable mechanism of the South-North Korean E-Market Place collaboration project. The feasibility of the project results from the newly installed fiber telecommunication network as well as the 1 billion dollars of the trading volume between South and North Korea. The research analyzes on the capabilities as well as willingness of the South and North Korea for the e-MP, and concludes with two paradigms of the future tasks. First, the unified but step-wise structure should be made to promote the project by the political committee (South and North Korea EC Committee) and the economical administration body (South and North Korea EC Corporation). Second, the market-oriented resolution system such as South and North Korea Arbitration Body should be involved to create legal environment. Above all, the discussion should be on the main body of e-MP settlement to abolish the psychological as well as practical barriers to enter the South-North Korean electronic commerce.