• Journal of the Korean Society of Food Culture
• /
• v.25 no.3
• /
• pp.342-349
• /
• 2010

This study evaluated the quality and sensory characteristics of sulgidduk added with yam powder (5~20%) during 4 days storage. The moisture content of samples initially decreased as the yam powder content increased, but subsequently increased during storage. The pH values also increased during storage, although there was no significant difference. L values decreased and both a and b values increased as yam powder content increased. The decreased L values during storage were not significantly different from control group. The hardness of samples decreased with increasing yam powder content, while hardness of control group markedly increased during storage. Cohesiveness increased as yam powder content increased, and tended to decrease during the storage. Springiness also initially increased as yam powder content increased. No change was apparent during storage in control group or samples added with up to 10% yam powder, while springiness was decreased insignificantly in samples with over 10% yam powder. Lightness, yam odor and savory taste of sulgidduk tended to increase as yam powder content increased, while chewiness decreased. The savory odor was the highest in sulgidduk added with 10% yam powder. Sulgidduk added with 10% yam powder was the most preferred in appearance, taste, texture and overall preference.

• Journal of Korean society of Dental Hygiene
• /
• v.23 no.6
• /
• pp.459-466
• /
• 2023

Objectives: The purpose of this study was to evaluate the physical properties and antibacterial activity of denture base resin with added silver sulfadiazine. Methods: Specimens were made from self-curing denture base resin and silver sulfadiazine as an inorganic antibacterial agent. For physical evaluation of the specimens, surface roughness, surface hardness, and contact angle were measured. Bacterial growth was assessed by optical densityat 600 nm (OD600) and colony forming units (CFU) measurements to confirm antibacterial activity. Results: There was no significant difference in surface roughness, surface hardness, and contact angle in the experimental group containing silver sulfadiazine compared to the control group. In contrast, the experimental group showed a significant decrease in antibacterial activity compared to the control group in terms of OD value. Analysis of CFU confirmed a significant decrease in colonies in the experimental group compared to the control group. Conclusions: Denture base resin containing silver sulfadiazine, an inorganic antibacterial agent, exhibited enhanced antibacterial activity without physical changes. In conclusion, the use of denture base resin containing inorganic antibacterial agents may be expected in the future.

• Journal of Life Science
• /
• v.18 no.6
• /
• pp.897-901
• /
• 2008

Deep seawater (DSW; deep ocean water) is pure, rich in inorganic materials which have attracted attention for various applications. In this study we investigated the effects of the DSW upwelled from the East Sea, offshore Yang Yang (Korea) on the morphological differentiation of cultured rat hippocampal neurons, which were grown in the minimal essential medium containing 10% (v/v) fetal bovine serum and 25% (v/v) DSW with various hardness. DSW had no effect on initial morphological differentiation (17 hr post-plating). When observed on DIV3, 7, 14, and 17, low hardness (0 and 200) DSW reduced dendritic branching. However, dendritic branches within $80\;{\mu}m$ diameter from the center of soma nearly doubled in neurons grown in hardness 1,000 DSW-containing media. DSW with hardness 600 was more or less same as control groups. These results indicate that DSW with appropriate hardness ameliorates neuronal health.

• Korean Journal of Materials Research
• /
• v.16 no.4
• /
• pp.218-224
• /
• 2006

RF sputtering process was applied to produce thin hydroxyapatite(HAp) films on Ti-6Al-4V alloy substrates. The effects of different heat treatment conditions on the hardness between HAp thin films and Ti-6Al-4V alloy substrates were studied. Before deposition, the Ti-6Al-4V alloy substrates were heat treated for 1h at $850^{\circ}C\;under\;3.0{\times}10^{-3}torr$, and after deposition, the HAp thin films were heat treated for 1h at $400^{\circ}C,\;600^{\circ}C\;and\;800^{\circ}C$ under the atmosphere, and analyzed FESEM-EDX, FTIR, XRD, nano-indentor, micro-vickers hardness, respectively. Experimental results represented that the surface defects of thin films decreased by relaxation of internal stress and control of substrate structure followed by heat treatment of substrates before the deposition, and the HAp thin films on the heat-treated substrates had higher hardness than none heattreated substrates before the deposition, and the hardness properties of HAp thin films and Ti-6Al-4V alloy substrates appeared independent behavior, and the hardness of HAp thin films decreased by formation of $VTiO_3(OH),\;{\theta}-Al_{0.32}V_2O_5,\;Al_{0.33}V_2O_5$.

• Journal of Technologic Dentistry
• /
• v.14 no.1
• /
• pp.55-65
• /
• 1992

The purpose of this study was to investigate the comparison of physical properties of nonprecious metal alloys colored goldish yellow. The experimental groups were copper based dental alloy and control group was Ni-Cr based dental alloy used crown and bridges frameworks. Hardness was tested by vickers hardness tester, tensile strength was tested by universal tension tester. After testing the tensile strength of castings, the microstrucure and the pattern of fracture were investigated by scanning electron microscope and metallurgical microscope. The results were as follows : Hardness of Ni based alloy was higher than Cu based alloys. Hardness number of A group was 200.41$\pm$16.10 Hv, B group was 194.33$\pm$1.69 Hv, C group was 139.29$\pm$2.19 Hv and D group was 293.81$\pm$27.17 Hv, respectively. Tensile strength of D group was 56.42$\pm$6.17 $kg/m^2$, A group was 50.39$\pm$5.68 $kg/m^2$, C group was 45.13$\pm$4.53 $kg/m^2$, B group was 45.25$\pm$9.25 $kg/m^2$, in order, and D group was maximum tensile strength. The fractured surfaces of tensile specimens in the all groups showed the tendency to form large voids in the center of specimens. Thus the ductile fracture was changed into the brittle fracture with the fine grain size.

• Restorative Dentistry and Endodontics
• /
• v.44 no.1
• /
• pp.1.1-1.12
• /
• 2019

Objectives: The aim of this in vitro study was to test the effect of 2 finishing-polishing sequences (QB, combining a 12/15-fluted finishing bur and an EVO-Light polisher; QWB, adding a 30-fluted polishing bur after the 12/15-fluted finishing bur used in the QB sequence) on 5 nanotech-based resin composites (Filtek Z500, Ceram X Mono, Ceram X Duo, Tetric Evoceram, and Tetric Evoceram Bulk Fill) by comparing their final surface roughness and hardness values to those of a Mylar strip control group (MS). Materials and Methods: Twelve specimens of each nanocomposite were prepared in Teflon moulds. The surface of each resin composite was finished with QB (5 samples), QWB (5 samples), or MS (2 samples), and then evaluated (60 samples). Roughness was analysed with an optical profilometer, microhardness was tested with a Vickers indenter, and the surfaces were examined by optical and scanning electron microscopy. Data were analysed using the Kruskal-Wallis test (p < 0.05) followed by the Dunn test. Results: For the hardness and roughness of nanocomposite resin, the QWB sequence was significantly more effective than QB (p < 0.05). The Filtek Z500 showed significantly harder surfaces regardless of the finishing-polishing sequence (p < 0.05). Conclusions: QWB yielded the best values of surface roughness and hardness. The hardness and roughness of the 5 nanocomposites presented less significant differences when QWB was used.

• The Korean Journal of Food And Nutrition
• /
• v.17 no.2
• /
• pp.171-176
• /
• 2004

The purpose of this study was to examine physical properties of the bread flour added two different commercial sour dough powder. Addition of sour dough powder didn't show different water absorption, but reduce stability and increase breakdown on farinogram. Initial pasting temperatures of bread flour were increased by 0.7-1.3$^{\circ}C$ when sour dough powder was added. Peak viscosity were increased by 3-6 RVA with addition of Phil IM 1, but addition of Phil XN 290 didn't show much difference with unadded bread flour Hardness of bread added Phil XN 290 and Phil IM 1 were lower than control after 2 days of making bread, but after 4 days they showed rapid increment. Sensory test showed that addition of Phil XN 290 2％ and Phil IM 1％ had better general evaluation than the others.

• Korean journal of food and cookery science
• /
• v.16 no.6
• /
• pp.670-676
• /
• 2000

Dohaengbyoung was prepared with the addition of glutinous rice at 0%, 10%, 20%, 30%, 40% or 50%, and their sensory quality and physical characteristics were compared. In sensory quality, the more glutinous rice was added, the higher the color intensity, moistness hardness, chewiness, springiness and cohesiveness were. Meanwhile, the more glutinous rice was added, the lower the color quality was. Dohaengbyoung with 20% glutinous rice showed the highest score in taste, texture, moistness and overall quality. The control sample with 0% glutinous rice showed the highest values in lightness(L) and redness(a) in color, and the more glutinous rice was added, the lower the values were. In textural characteristics, as the amount of glutinous rice increased, the hardness, cohesiveness, gumminess and brittleness of Dohaengbyoung were increased. The lightness and redness were negatively correlated with the moistness, hardness, cohesiveness and springness； however, they were positively correlated with the color quality. Scanning electron microscopy revealed that the addition of glutinous rice to Dohaengbyoung exhibited small pores and coarse surface.

• Korean Journal of Soil Science and Fertilizer
• /
• v.30 no.1
• /
• pp.46-50
• /
• 1997

This study was conducted to find out the main soil physical properties to control the soil hardness in tamped condition. Sandy loam soil was taken and fill it up to wood cubes and then differently trampling experimental cubic lots which were mulched with various materials, such as, leaves, wood plates and bricks. Soil physical properties were measured 2" core and samples were taken at 250 sites with soil hardness. There were highly significant positive correlations between soil hardness and bulk density, and between bulk density and water content. Negative correlations were found between soil hardness and water content, and between soil hardness and gravel content. The correlation coefficients were increased by multiple correlation between soil hardness, bulk density, volumetric water and gravel content. Bulk density was the main factor to control the hardness, and volumetric water and gravel contents were less effected to soil hardness.

• Journal of the Korean Dietetic Association
• /
• v.19 no.3
• /
• pp.195-208
• /
• 2013

The purpose of this study was to evaluate the quality characteristics of chicken sausage prepared with turmeric (Curcuma longa L.) powder (T) during storage at $4^{\circ}C$ for 20 days. The pH and color values (a and b values) of sausage containing turmeric powder were significantly higher (P<0.05) than the control for both uncooked and cooked sausage. The hardness, chewiness, and gumminess of control sausage significantly changed after 15 days of storage, while the hardness and gumminess of turmeric-supplemented sausages (T) significantly increased after 5 days (until 15 days) for cooked sausages. The total phenolic content and DPPH radical scavenging activity of turmeric-supplemented sausages was significantly higher (P<0.01) than the control for both uncooked and cooked sausage during storage. On the other hand, the acid value of the control was higher than the turmeric-supplemented sausages and the peroxide value of the control was significantly higher (P<0.05) than the turmeric-supplemented sausages after 15 days of storage. Microorganism analysis revealed that total plate counts of uncooked and cooked control sausages were significantly higher (P<0.05) than turmeric-supplemented sausages at 20 days of storage. As a result, sausages prepared with turmeric powder demonstrate antioxidative activity and lipid oxidative stability during storage.