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Lee KH Kim BS Keum KS Yu HH Kim YH Chang BS Ra JY Moon HD Seo BR Choi NY You YO 《Journal of food science》2011,76(9):H226-H230
Curcuma longa (C. longa) has been used as a spice in foods and as an antimicrobial in Oriental medicine. In this study, we evaluated the inhibitory effects of an essential oil isolated from C. longa on the cariogenic properties of Streptococcus mutans (S. mutans), which is an important bacterium in dental plaque and dental caries formation. First, the inhibitory effects of C. longa essential oil on the growth and acid production of S. mutans were tested. Next, the effect of C. longa essential oil on adhesion to saliva-coated hydroxyapatite beads (S-HAs) was investigated. C. longa essential oil inhibited the growth and acid production of S. mutans at concentrations from 0.5 to 4 mg/mL. The essential oil also exhibited significant inhibition of S. mutans adherence to S-HAs at concentrations higher than 0.5 mg/mL. S. mutans biofilm formation was determined by scanning electron microscopy (SEM) and safranin staining. The essential oil of C. longa inhibited the formation of S. mutans biofilms at concentrations higher than 0.5 mg/mL. The components of C. longa essential oil were then analyzed by GC and GC-MS, and the major components were α-turmerone (35.59%), germacrone (19.02%), α-zingiberene (8.74%), αr-turmerone (6.31%), trans-β-elemenone (5.65%), curlone (5.45%), and β-sesquiphellandrene (4.73%). These results suggest that C. longa may inhibit the cariogenic properties of S. mutans. 相似文献
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Dong-Ju Lee Se-June Park Ki-Suk Woo No-Cheol Park Young-Pil Park 《Microsystem Technologies》2005,11(7):470-477
Recent advancements in mobile devices have fueled a requirement for information storage systems with characteristics such as subminiature size, low cost, and minimum power consumption. Small optical disk drives could provide a good solution, because their storage media is cheaper than those of hard disk drives or flash memories. In this study, we design and analysis a linear voice coil motor (VCM) types actuator for the coarse and fine tracking motions and a two-wire spring types actuator for a fine focusing motion in order to apply them to small-sized optical disk drives of high data capacity. And, we make the mathematical model of a two-wire spring types actuator and find proper conditions to suppress the tilt motion of the lens holder for various focusing offset positions without sacrificing the sensitivity. Based on them, we design and modify the magnetic circuit and the structural part. Finally, we verify that the designed actuator had the proper dynamic characteristics and that it could be used in small optical disk drives by simulations and experiments. 相似文献
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Jung-Ki Park Dong-Won Kim Chul-Hwan Kim Ki-Suk Maeng Taek-Sung Hwang Young-Chul Kim 《Polymer Engineering and Science》1991,31(12):867-872
Systematic changes of drying conditions of poly(acrylic acid) were tested to study their effect on the glass transition of the material. The materials were synthesized in two different mediums of water and benzene, respectively. The glass transition temperatures of the samples were determined by thermal analysis using DSC. The samples were also characterized by IR spectra. The glass transition of poly(acrylic acid) was found to be significantly dependent on the drying conditions and also dependent on the medium in which poly(acrylic acid) was prepared. The anhydride formation in poly(acrylic acid) was increased as the drying temperature was raised, resulting in the increase of the glass transition temperature. The “bound” water involved in the preparation of poly(acrylic acid) in water medium could affect significantly the glass transition of the sample. A significant discrepancy in the previously reported values of the glass transition temperature of poly(acrylic acid) seems to be due to the differences in the drying conditions of the materials. 相似文献
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Xiaowei Shi Ki-Suk Yoo Jae-Hong Park Hyuck-Jae Lee 《Electronics letters》1997,33(12):1007-1008
A pencil-beam pattern is synthesised, based on maximisation of the signal-to-interference-plus-noise ratio (SINR). Artificial interference is introduced and is iteratively adjusted to approximate the desired pattern. In particular, a set of linear equations is derived to find an efficient adjustment for the artificial interference which makes the iterations converge quickly 相似文献
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El Mostafa Hee-Yeoun Jeong-Suong Juh-Wan Ki-Suk Jong-Hyeong Sang-Kyeong 《Sensors and actuators. A, Physical》2009,155(2):290-298
Time-dependent deformation (creep) behaviors of piezoelectric microactuators have been investigated. Position (or gap height) drift of microbridged actuator beam and its displacement amplitude change with time could be attributed to the anelastic behavior of the driving unit itself based on lead zirconate titanate (PZT) in the actuator, and as well as to the mechanical stress states established in the microactuator beam after the surface release of the micromachined actuator structure. From creep analyses of a simple microcantilever and microbridge beam structures, it was turned out that the overall creep behavior in microbridged piezoactuator structure was mainly dependent on the actuator beam initial deflection configuration governed both by residual stress of the actuating part Pt/PZT/Pt stack and the stress gradient through the silicon nitride (SiNx) microbridge beam. 相似文献
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