• Journal of the Korean Graphic Arts Communication Society
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• v.20 no.2
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• pp.7-18
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• 2002

The emulsification of lithographic printing inks are very important to determine printing quality. In this study, we measured the variation of water pickup according to the hardness of water in dampening solution. In order to observe the rheorogical properties of the emulsified inks, we measured the viscosity, the elastic return, the thixotropy area and yield stress value of the emulsified inks. In this paper, we found that the water pickup of the ink increase the hardness of water with the amount of dampening solution. Also, The viscosity, the yield stress value and the thixotropy area were increase by the water pickup of the ink.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.1
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• pp.75-81
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• 1998

We have studied internal quality including chemical compositions, microscopic structure and nonmetallic inclusion of test materials. We have analyzed tensile strength value, hardness value, impact value etc. In analyzing internal quality, all of the test materials showed typical ferrite+pearlite structure. But nonmetallic inclusion showed oxide and sulfide inclusions in medium carbon steels, and sulfide inclusion is S-free cutting steels. In ca+ S-free cutting steels, the calcium aluminate and sulfide complex inclusion had low-melting points as deformation of sulfide and oxide inclusion is existed. It was found that tensile strength and hardness give maximum value in medium carbon steels, where as minimum in Ca + -free cutting steels. But values of elongation, reduction of area impact are reverse. Fracture surface of impact specimen is ductile in free cutting steels but brittle in medium cabon steels.

• The Korean Journal of Community Living Science
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• v.11 no.1
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• pp.1-8
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• 2000

The characteristics of rice-breads with wet-milling and dry-milling rice-flours were investigated. Rice-breads by wet-milling had a good fermentation than the breads by dry-milling. Also, the fermentation of mugwort rice-breads was lower than those. Rice-breads by dry-milling indicated the higher value in hardness and the lower value in springiness, cohesiveness and chewiness than rice-breads by wet-milling. Also, mugwort rice-breads was the higher value in hardness, springiness, chewiness and the lower value in cohesiveness than rice breads. The test of the sensory characteristics for rice-breads showed that moistness, springiness, chewiness was higher for rice-breads by wet-milling. The sensory characteristics of mugwort rice-breads were lower than those, of rice-breads except the chewiness. Overall quality of rice-breads by wet-milling was higher than that of rice-breads by dry-milling. The overall quality of mugwort rice breads was higher than that of rice-breads by wet-milling, but lower than that of rice-breads by dry-milling.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.1073-1077
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• 1997

In this paper, we have studied internal quality including chemical compositions, microscopic structure and nonmetalic inclusion of test materials. We have analyzed machining characteristics including tensile strength value, impact value, hardness value etcs. Test materials are usd martensitic heat resisting steel, STR11 and STS420J2. The obtined results are as follows : 1. In analyzing internal quality, STR11 and STR420J2 have typical martensite structure and a minute needle-shaped structure. 2. Tensile strength and reduction of area and hardness value are large STR11 than STS420J2. But elongation impact are smaller STR11 than STS420J2. 3. Fracture surface of tensile speciman is ductile in STR11 and STS420J2.

• Korean journal of food and cookery science
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• v.16 no.3
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• pp.226-231
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• 2000

Injulmi, a kind of traditional Korean sticky rice cakes, was prepared with the mixed flours of waxy and black rices in different ratio(0% to 25% black rice flour), and their quality properties were studied. In the sensory evaluation, the best acceptance was shown in the samples with 15% black rice flour. The scores for hardness, coarseness. chewiness, and flavor were increased as the added amount of black rice flour increased. The moisture content of the samples ranged from 43 to 45%, and it was increased as the added amount of black rice flour increased. In color value, lightness(L value) was 27.43∼65.63. The redness(a value) was -2.01∼4.74, and the yellowness(b value) was -1.40∼4.59. The redness and blueness were increased by the increase of black rice flour. In the texture properties, the increase of added black rice flour increased the hardness, chewiness, and gumminess of Injulml, but decreased the adhesiveness. Based on the results, the optimal recipe for Injulmi added black rice flour was to make with 85% waxy rice flour ant 15% black rice flour.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.81-82
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• 2019

In this study, the Proctor penetration resistance test value and the hardness value of the improved Durometer were compared and analyzed for the change in the FA replacement rate of the concrete using CGS fine aggregate. The results are summarized as follows. It is. 1) The Proctor penetration resistance test value and the hardness value of the improved Durometer showed a high correlation in the form of a curve. 2) About surface finish Super-resolution with the improved Durometer is considered to be useful when using about 50 HD and about 80 HD in the end to determine the surface finishing work time.

• Journal of Conservation Science
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• v.25 no.4
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• pp.431-438
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• 2009

We have investigated the suitable measuring method and condition on the hardness testing for the earthenwares excavated from Poongnap mud castle in Hanseong Baekje period. The earthenwares which used on hardness testing have been classified according to Mohs hardness and external form and color. The Ultrasonic and Equotip testing method have used to the hardness testing on the surface of the earthenwares and the Rockwell and Micro-vickers testing methods have used to the hardness testing on the cross section of the earthenwares. As the results, the two methods applied to the surface of the earthenwares were very hard on the precise measurement and the measuring values were incompatible with the tendency classified according to Mohs hardness and external form and color. On the testing for the cross section of earthenware, the Rockwell-superficial hardness testing method was more suitable for the soft texture earthenware and highest reproducibility of the measuring value obtained at the test load and indentor are 15kgf and 1/16 “iron ball, respectively. The Micro-Vickers hardness testing method was suitable for the hard texture earthenware and highest reproducibility and accuracy of the measuring value obtained at the test load is 100gf. This results show strong possibility of progress on the classifying and comparing study for hardness of the earthenware and therefore active studies are expected on the field.

• The Journal of Korean Academy of Prosthodontics
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• v.9 no.1
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• pp.23-27
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• 1969

The purpose of this studies is to determine the surface hardness of dental stone and to investigate the methods which increase the surface hardness of dental stone using the dissolved solution of various synthetic resin, the obtained results of hardness value calculated Rockwell Hardness Number by means of Rockwell Hardness Tester. 1) In this experiment, 10% polystyrene dissolved in 100cc amylacetate is excellent solution which provides the surface hardness of dental stone after setting of specimen, and there is no effective way that stone specimen is immersed into polystyrene in amylacetate, polystyrene in benzene and polystyrene in butylacetate above 1 hour. 2) When the stone specimen is immersed into acrylic resin in benzene and melamin resin in amylacetate at least 1 hour to 3 hours, the hardening effect of stone surface is valuable. 3) The stone specimen immersing into urea resin in butylacetate, the surface hardness of the stone specimen decreased within 1 hour, but increased after 3 houre. 4) For the separating medium, the easyfoil is superior to the olive oil in the aspect of improving the hardening effect of the immersed specimen.

• Journal of Power System Engineering
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• v.21 no.3
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• pp.37-44
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• 2017

In this study, failure analysis of the angular pin for molding machines to aluminum component molding was carried out. SM45C steel was used for the angular pin, it was surface hardened by the induction surface hardening heat treatment. The cross section of damaged angular pin was observed, and micro Vickers hardness value from the fractured part was measured. Brittle fracture was occurred from the fracture surface of angular pin, therefore, impact toughness value was evaluated by V-notch Charpy impact test. It was confirmed that the impact absorption energy was high when was tempered at a high temperature for a long time, and the toughness was slightly increased. Also, 2-parameter Weibull statistical analysis was investigated in order to evaluate the reliability of the measured micro Vickers hardness values and absorbed energy. The micro Vickers hardness and absorbed energy well followed a two-parameter Weibull probability distribution, respectively. The reverse design against angular pin was proposed as possible by using test results.

• Proceedings of the KWS Conference
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• 2002.10a
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• pp.534-538
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• 2002

Dissimilar friction stir welding of aluminum (AI) alloy 1050 and magnesium (Mg) alloy AZ31 was successfully done in the limited welding parameters. The dissimilar weld showed good quality and facility compared to conventional fusion weld. Transverse cross section perpendicular to the welding direction had no defects. The weld was divided into base material of Al alloy, an irregular shaped stir zone and base material of Mg alloy. The irregular shaped stir zone was roughly located around the initial weld center. The weld interface near plate surface shifted from initial weld centerline to the advancing side. Hardness profile of the weld was heterogeneous, and the hardness value of the stir zone was raised to about 150 Hv to 250 Hv. The mixed phase was identified to intermetallic compound $Mg_{17}$Al$_{12}$ using x-ray diffraction method, energy dispersive x-ray spectroscopy (EDX) and electron probe micro analysis (EPMA). The formation of intermetallic compound $Mg_{17}$Al$_{12}$ during FSW causes the remarkable increase in hardness value in the stir zone.one.