• Elastomers and Composites
• /
• v.40 no.3
• /
• pp.174-180
• /
• 2005

Sonochemical synthesis of fullerene oxides $[C_{70}O_n](n=1{\sim}2)$ by fullerene$[C_{70}]$ and metal hexacarbonyl complexes $M(CO)_6$(M=Cr, Mo, W) took place under air atmosphere. The reactivity of fullerene$[C_{70}]$ and several metal hexacarbonyl complexes $M(CO)_6$(M=Cr, Mo, W) under same ultrasonic condition increased in the order of $Mo(CO)_6$ > $W(CO)_6$ > $Cr(CO)_6$. The MALDI-TOF-MS, UV-visible spectra, and HPLC analysis confirmed that the products of sonochemical reaction were $[C_{70}O_n](n=1{\sim}2)$.

• Journal of Periodontal and Implant Science
• /
• v.24 no.1
• /
• pp.144-154
• /
• 1994

Final goal of periodontal treatment is to reconstruct the destructed periodontal tissue as well as to remove the necrotic pathologic elements. The purpose of this study is to investigate on the effect of Zizyphi extract to the inhibitory ability on collagenolytic activity of P gingivalis, biologic activity of gingival fibroblasts, and on the collagen and protein synthesis of gingival fibroblasts. Gingival fibroblast from giniva of first bicuspids from patient for orthodontic treatment were used and cultured. For the measurement of inhibitory ability of collagenolytic activity, crude enzyme was extracted and used on the basis of modified Ono's method. On the inhibition of collagenolytic enzyme from herbal extracts, collagenokit CLN-100 were used. The cellular activity of gingival fibroblast, were studied using MTT solution and measured optical density on 570mm by ELISA reader. To measure the effects on the ability of whole protein and collagen synthesis, cell membrane was destructed with ultrasonic grinder after culturing, centrifuged and counted by liquid scintilation counter. The inhibitory effects on producing of $IL-l{\beta}$ by monocyte, after promotion of producing $IL-l{\beta}$ by LPS, were compared with the mixture of herbal extracts and other drugs using thymocyte stimulation assay. About inhibitory effects of $PGF_2$. by gingival fibroblasts, herbal extract was compared with the addition of the other control groups using enzyme imunoassay. On the inhibition of collagenolytic activity by P. gingivalis, benzene extracts showed the most efficient inhibitory effects among the $19{\mu}g/ml$ of the compared extracts and 40.5% by Tetracycline. On the cellular activity promoting effects, compared extracts showed a bit of more effects than PDGF of $100{\mu}g/ml$ concentration and IGF of $20{\mu}g/ml$ concentration. All of the PDGF, IGF, Zizyphi Fructus extract should increase in collagen synthesis, but especially 70% ethylalcohol extracts of Zizyphi Fructus showed comparably high effects among the compared extracts. Effects on whole protein synthesis were slightly increased on every extract but especially 70% ethylalcohol extract showed significantly effective than any other estract. On the inhibitory effects of Zizyphi Fructus $IL-l{\beta}$ production by monocyte, compared extracts showed 70% of highly inhibitory effect than that of 60% inhibition effects on controlled group and each extracts showed no significant difference. In $PGF_2$ production inhibitroy effect of Zizyphi Fructus gingival fibroblasts, Herbal extracts showed 70% of inhibition comparing with tat of 90.2% of controlled group, but each extracts showed similar effects excluding the $H_2O$ extracts. These results suggested that Zizyphi Fructus might be useful medicine for inhibition of inflammatory mediator including $IL-l{\beta}$ and $PGF_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.05a
• /
• pp.192-195
• /
• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT was prepared from a mixture of PZT an polyvinylacohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The piezolectirc and acoustic properties with various PVA wt% were studied, Piezoelectric coefficient d$\sub$33/ of porous PZT ceramics was almost same to that of single phase PZT ceramics, The thickness mode coupling factor k$\sub$t/ was 0.53~0.59 in comparable with the single phase PZT ceramics(k$\sub$t/=0.7)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1995.11a
• /
• pp.205-208
• /
• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT specimens were prepared from a mixture of PZT and Polyvinylalcohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The pulse-echo response of PZT-polymer 3-3 type composite transducer with various PVA wt.% were studied, The fall time of pulse-echo response of PZT-polymer 3-3 type composite transducer was shorten to that of solid PZT-maded transducer. Therefore, a good transmitting and receiving properties could be obtained. The distance between transducer and reflector was in good agreement both solid PZT and PZT-polymer 3-3 type composite fabricated transducer.

• Journal of the Korean Ceramic Society
• /
• v.28 no.9
• /
• pp.739-749
• /
• 1991

Calcium hydroxide fine powders were synthesized by hydration of calcium oxide, and the shapes of powders obtained were examined for each synthethic condition. When distilled water was used as a solvent, irregular and agglomerated submicron powders were obtained, and it was impossible to control of the shapes. In methanol-added solutions, hexagonal plate-like particles were obtained, but addition of ethanol had no effect. However on the occasion that substituted ethylene glycol for ethanol of 5 vol%, hexagonal plate-like powders were obtained. The shapes of powders synthesized in acetic acid and salicylic acid solutions were hexagonal platelike, and were spherical and very fine in citric acid and oxalic acid solutions, respectively. But in some solutions, calcium salts were precipitated by the reaction between calcium and acid added. And the size of powders were very fine using ultrasonic vibration instead of mechanical agitation.

• Proceedings of the KIEE Conference
• /
• 1995.11a
• /
• pp.358-360
• /
• 1995

PZT powders were prepared by the molten salt synthesis method. The porous PZT specimens were prepared from a mixture of PZT and polyvinylalcohol(PVA) powders by BURPS(Burnout Plastic Sphere) technique. The pulse-echo response of porous PZT transducer with various PVA wt.% were studied. The fall time of pulse-echo response of porous PZT transducer was shorten to that of solid PZT-maded transducer. Therefore, a good transmitting and receiving properties could be obtained. The distance between transducer and reflector was in good agreement both solid PZT and porous PZT fabricated transducer.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2003.10a
• /
• pp.99-102
• /
• 2003

Many researches on synthesis process for BSCCO precursor powders have been developed for high J$_{c}$ BSCCO-2223/Ag tape. Spray pyrolysis method for fabrication of precursor powder has many advantages, such as high purity, fine particle size of BSCCO precursor powder. Fine, spherical powders were prepared by ultrasonic spray pyrolysis from the aqueous solution of metal nitrates. BSCCO precursor powders were synthesized with 0.1 M concentration and heat treatment conditions. Average particle size for spray pyrolysis powders was 1.5 ~ 3 ${\mu}{\textrm}{m}$. BSCCO -2223/Ag tape was prepared by PIT method and followed by various sintering conditions. The critical current density of BSCCO-2223/Ag tape sintered in low oxygen partial pressure was ~ 23 kAcm$^{-2}$.

• Journal of the Korean Ceramic Society
• /
• v.54 no.3
• /
• pp.205-210
• /
• 2017

In this study, we examined the photo-degradation efficiency of $CoSe_2$-Graphene-$TiO_2$ ($CoSe_2-G-TiO_2$) nanocomposites under visible light irradiation using rhodamine B (RhB) as standard dye. $CoSe_2-G-TiO_2$ nanocomposites were synthesized by ultrasonication and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopic analysis and UV-Vis absorbance spectra analysis. Our results show that the $CoSe_2-G-TiO_2$ nanocomposite exhibited significant photo degradation efficiency compared to pure $TiO_2$ and $CoSe_2-G$, approximately 85.2% of the rhodamine (Rh B) degraded after 2.5 h. It is concluded that the $CoSe_2-G-TiO_2$ nanocomposite is a promising candidate for use in dye pollutants.

• Journal of the Korean institute of surface engineering
• /
• v.51 no.4
• /
• pp.202-206
• /
• 2018

Permalloy($Ni_{80}-Fe_{20}$) which is known for its soft magnetic properties is a well-known material that has been studied intensively. Permalloy nanoflakes were fabricated with the combination of electrodeposition and sonication process. Ultrasonic power was applied to the deposited alloy which produced nanoflakes in forms of sheet. High internal stress created cracks which helped the peeling of permalloy into nanosheets. Because of shape anisotropy, flakes could be aligned by magnetic field. The magnetic properties of the nanosheets were observed, and the variation of magnetic properties with the alignment of flake was also investigated.

• Journal of Biomedical Engineering Research
• /
• v.25 no.3
• /
• pp.201-206
• /
• 2004

The bone formation and re-formation are regulated by two factors that are the synthesis of bone matrix by osteoblast and reabsorption by osteoclast. Recently, there are many studies about regeneration and healing of bone tissue by activation of osteoblast. In general, it is known that the activation of osteoblast is influenced by not only biological stimulus but physical stimulus. In this study, we verified that ostoeblast activation was influenced by low intensity ultrasound. Various ultrasonic properties were used to find out the most appropriate condition on cell activation. From this study, we could confirm that 0.3W/$\textrm{cm}^2$ intensity of ultrasound was the most appropriate to tell activation over whole duty cycles and the increasing rate of tell was the highest at 50％ duty cycle. Thus, it is expected that optimal ultrasonic characteristics on regeneration of bone matrix may be applied to fracture and osteoporosis healing.