2007, Vol.17, No.6

Journal of the Korean Crystal Growth and Crystal Technology 2023 KCI Impact Factor : 0.19

pISSN : 1225-1429 / eISSN : 2234-5078
https://journal.kci.go.kr/jkcgct

For an aspect ratio (transport length-to-width) of 5, Pr = 3.34, Le = 0.078, Pe = 4.16, Cv = 1.01, PB = 50 Torr, only thermally buoyancy-driven convection (Gr = 4.83 × 10 5 ) is considered in this study in spite of the disparity in the molecular weights of the component A (Hg2Cl2) and B which would cause thermally and/or solutally buoyancy-driven convection. The crystal growth rate and the maximum velocity vector magnitude are decreased exponentially for 3 ≤ Ar ≤ 5, for (1) adiabatic walls and (2) the linear temperature profile, with a fixed source temperature. This is related to the finding that the effects of side walls tend to stabilize convection in the growth reactor. The rate for the linear temperature profiles walls is slightly greater than for the adiabatic walls for varied temperature differences and aspect ratios. With the imposed thermal profile, a fixed source region, both the rate and the maximum velocity vector magnitude increase linearly with increasing the temperature difference for 10 ≤ ΔT ≤ 50 K.e

Nano-sized ZnO crystals were successfully incorporated using ion exchange method in TMA-A zeolite synthesizedby the hydrothermal method. The optimal composition for the synthesis of TMA-A zeolite was resulted in a solution ofAl(i-pro)3 : 2.2 TEOS : 2.4 TMAOH : 0.3 NaOH : 200 H2O. 0.3 g of TMA-A zeolite and 5 mol of ZnCl2 solution were em-from the process of mixing, stirring, centrifugal separation and drying, were calcined at temperatures from 400 to 60oCfor 3 h. The crystalization proces of ZnO incorporated TMA-A zeolite was analyzed by X-ray diffraction (XRD). TheBrunaur-Emett-Teller (BET) surface area of the ZnO incorporated TMA-A zeolite was measured. Subsequently, the morphologyand the particle size depending on the temperature and time were observed using scanning electron microscopy(SEM),transmission electron microscopy(TEM) and particle size analyzer.Key words ZnO, TMA-A zeolite, Nanocrystal, Incorporation, Hydrothermal, Ion exchangeZnO. ... TMA-A ..... ..... ....... ...†.. ........ ...... , .. , 356-706(2007. 10. 9. .. )(2007. 12. 10. .... )

We made (1 . x)BCB . xBNT(BaNd2Ti4O12) (x = 20, 30, 40, 50 vol%) composite thick film with a high dielectric constant and low loss by the hand casting method. Dielectric constant and dielectric loss of prepared thick film are measured at 1MHz and curing behavior of the film are observed through thermal analysis such as DSC. We investigated the effect of contents of BNT filler and curing behavior of film on dielectric properties of BCB-BNT composite. Dielectric constant increased with increasing BNT filler from 20 to 50 vol% and dielectric loss (tanδ) decreased with increasing BNT filler. Dielectric constant and loss (tanδ) of composite material was not nearly dependent on the curing behavior. But as a result of TCC (Temperature Characteristics of Coefficient) decreased with increasing the curing temperature, we confirmed that the curing of these composite system is most stable above 250 o C._sign