• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.119-126
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• 2007

Generally, the machinability of materials that have a good mechanical properties is poor. The material having a high strength, high toughness in high temperature and wear resistance, it is difficult to remove a chip from workpiece. STD11 and NAK80 are kinds of these materials and these materials can be used in many industrial fields. But it is limited in use because of high cost and poor machinability. In this experimental study, the cutting of STD11 and NAK80 were used to decide the machinability and the tool shape of CBN ball end mill. From the results, the CBN ball end mill is verified that the estimated cutting edge shape of rake angle 30 degree has consistent effect on the tool wear and cutting force.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.62-68
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• 2017

Since the aircraft parts industry is a high-value-added industry, mass production order production, and the hundreds of thousands. Therefore, parts produced However, since these parts require high reliability and stability, a high degree of precision is required. In Korea, there on the roughness of the machined surface in cutting process. However, research on the surface roughness characteristic obtained by which is widely used for aircraft parts is still insufficient in Korea. The purpose of this study is to investigate the effect of turning tool rotation speed and X axis feed rate on the surface roughness of cutting tools in CNC lathes during cutting of aluminum alloy 7075.

• Journal of Powder Materials
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• v.13 no.6 s.59
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• pp.432-438
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• 2006

Aluminum nitride (AlN) nanopowders with low degree of agglomeration and uniform particle size were synthesized by carbothermal reduction of alumina and subsequent direct nitridization. Boehmite powder was homogeneously admixed with carbon black nanopowders by ball milling. The powder mixture was treated under ammonia atmosphere to synthesize AlN powder at lour temperature. The effect of process variables such as boehmite/carbon black powder ratio, reaction temperature and reaction time on the synthesis of AlN nanopowder was investigated.

• Textile Coloration and Finishing
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• v.20 no.4
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• pp.53-59
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• 2008

For the modification of wool surface, wool fabrics treated with oxygen low-temperature plasma(LTP) and dichloroisocyanuric acid(DCCA) were dyed with milling type acid dye. The difference of dyeing properties on modified and control wool fabric were investigated. DCCA treated wool showed that saturation dye uptake and dyeing desorption ratio were higher than LTP treated wool. Dyeing transition temperatures of DCCA and LTP treated wool fabrics were 20$^{\circ}C$ degree lower than control wool fabric. In light color fastness test, DCCA treated wool fabric was 1 grade lower than LTP or control wool fabric.

• Progress in Superconductivity
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• v.1 no.2
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• pp.95-98
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• 2000

We have studied critical currents of $YBa_2Cu_3O_7$ step-edge junctions with different step orientations with respect to the major axes of $SrTiO_3$ (100) substrates. The junctions were prepared by pulsed laser deposition and argon ion milling with photoresist mask. We investigated current-voltage characteristics and critical current of the junctions as a function of the angle. The junction critical current showed an angle dependent modulation with maxima near 0 or 90 degree and minima near 45 and 135 degrees. The experimental results were analyzed based on the microstructure of the junction along the step and the d-wave symmetry of $YBa_2Cu_3O_7$ superconductor.

• Journal of Powder Materials
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• v.1 no.2
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• pp.167-173
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• 1994

Cu-10wt%W composite powders have been manufactured by a high energy ball milling technique. The composite powders were pressed at 250 MPa and sintered in a dry hydrogen at 103$0^{\circ}C$ for 4 hours. After sintering, Cu-10wt%W composite materials were forged. And the arc-resistance of forged materials which have the same relative density of 94% has been tested. Composite particles, i.e. tungsten particles distributed homogeneously in the copper matrix, was formed after 480 min mechanical alloying. Densities of these sintered materials were ranged from 74 to 84%. Densification degree was due to the formation of composite powders. As the mechanical alloying time increased, the hardness was increased and tungsten particle size was decreased. Arc loss of the forged specimens was decreased as increasing the mechanical alloying time.

• Food Science and Preservation
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• v.19 no.6
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• pp.858-865
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• 2012

In this research, the soaking and steaming conditions of Korean wheat meju according to the degree of milling were investigated, and the quality characteristic was analyzed, for the manufacture of the standardized Korean wheat meju. As a result of the changes in weight, volume, moisture content, and moisture absorption amount, which indicate the physical properties of Korean wheat meju using 20% polished wheat, 50% polished wheat, whole wheat, and whole wheat flour, most of the wheat materials reached the equilibrium state after 4 hours of soaking. Also, the appropriate steaming time to complete the cooking of the wheat materials was found to be 10 min at $100^{\circ}C$, except for whole wheat. The 20 and 50% polished wheat materials were selected for Korean wheat meju based on the soaking and steaming results. The selected wheat materials were fermented using Aspergillus oryzae and Bacillus subtilis M1, respectively, and the quality properties and enzyme activities showed that A. oryzae would be effective for the manufacture of Korean wheat meju. Also, the 50% polished wheat showed higher total sugar content, reducing sugar content, and ${\alpha}$-amylase activity than the 20% polished wheat. Therefore, it is supposed that the fermentation of 50% polished wheat by A. oryzae would be appropriate for manufacturing superior Korean wheat meju.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.271-279
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• 1991

The changes in fat acidity of brown rice and eating quality of rice during long term grain storage of unhulled rice were evaluated for the government managed rices. The Tongil type rice grains had consistently significantly lower fat acidity during three and half year storage than the Japonica type rice. On sensory evaluation of the fresh milled cooked rice the eating quality of the long term stored rices, 1987, 1988, and 1989 produce Tongil did not differ much each other even though increase in fat acidity by year of storage. The Japonica rices produced in 1989 and 1990 in different locations and stored there also did not differ much in eating quality. The grains stored in storehouses of super grade did not differ significantly from those stored in the first grades, but the grains stored (4 $^{\circ}C$, RH 50%) grains have kept the eating quality almost same as the fresh grains even after two and half years. A higher degree of milling did not improve significantly the sensory taste of cooked rice of the grains long term stored.

• Korean Journal of Materials Research
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• v.28 no.6
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• pp.343-348
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• 2018

Recently, the properties of nanostructured materials as advanced engineering materials have received great attention. These properties include fracture toughness and a high degree of hardness. To hinder grain growth during sintering, it is necessary to fabricate nanostructured materials. In this respect, a high-frequency induction-heated sintering method has been presented as an effective technique for making nanostructured materials at a lower temperature in a very short heating period. Nanopowders of W and $Al_2O_3$ are synthesized from $WO_3$ and Al powders during high-energy ball milling. Highly dense nanostructured $W-Al_2O_3$ composites are made within three minutes by high-frequency induction-heated sintering method and materials are evaluated in terms of hardness, fracture toughness, and microstructure. The hardness and fracture toughness of the composite are $1364kg/mm^2$ and $7.1MPa{\cdot}m^{1/2}$, respectively. Fracture toughness of nanostructured $W-Al_2O_3$ is higher than that of monolithic $Al_2O_3$. The hardness of this composite is higher than that of monolithic W.

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.262-274
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• 1995

A rice mill pilot plant was designed and developed in the basis of the simulation results on the mill plants. The performance of the developed rice mill plant was evaluated, and the simulation model on the mill system was validated with the experimental data in the mill plant. The results of this study were as followings : 1. A rice mill pilot plant with the capacity of 0.5 t/h was designed and developed. 2. The hulled ratio of the mill plant was 87.3%, and the milled rice recovery and the head rice recovery of the cleaned rice were 74% and 87% , respectively. The degree of milling of the cleaned rice was 10.6% with a high polish. The intensity of the cleaned rice appeared high compared with that of the milled rice in the analysis of whiteness test using an image processing system. 3. The bottleneck, processing time, and production amount of the developed mill system almost coincided with those of the simulation of the rice mill plant. The developed simulation model of the rice mill plant was proven to be applicable to the design of a rice mill plant through experiments.