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101.
Praseodymium doped Bi4Ti3O12 (BIT) ceramics with composition Bi2.9Pr0.9Ti3O12 (BPT) were prepared by solid state reaction. These samples have polycrystalline Bi-layered perovskite structure without preferred orientation, and consist of well-developed plate-like grains with random orientation. Pr doping into BIT causes a large shift of the Curie temperature (TC) of the BIT from 675 to 398 °C. At an electric field of 87 kV/cm, the remanent polarization and the coercive field of the BPT ceramics are 30 μC/cm2 and 52 kV/cm, respectively. Furthermore, the dielectric permittivity and the dissipation factor of the BPT ceramics are 300 and 0.003 at 1 MHz, 1 V, and room temperature. Ferroelectric properties of the BPT ceramics are superior to V-doped Bi4Ti3O12 (∼20 μC/cm2 and 80 kV/cm) and (Sr, Ta)-doped Bi4Ti3O12 (∼12 μC/cm2 and 71 kV/cm) ceramics. In addition, the dense ceramics of praseodymium-doped B4Ti3O12 were obtained by sintering at 1100 °C, about 100-200 °C lower than those of the SrBi2Ta2O9 system. 相似文献
102.
MID-FACETS OF A SIMPLEX 总被引:1,自引:0,他引:1
The mid-facet of a simplex in n-dimensional Euclidean space which was introduced quite recently is an important geometric element. An analytic expression for the mid-facet area of a simplex is firstly given. In order to obtain the expression, the exterior differential method was presented. Furthermore, the properties of the mid-facets of a simplex analogous to median lines of a triangle ( such us for all mid-facets of a simplex,there exists another simplex such that its edge-lengths equal to these mid-facets area respectively, and all of the mid-facets of a simplex have a common point) were proved.Finally, by applying the analytic expression, a number of inequalities which combine edge-lengths, circumradius , median line, bisection area and facet area with the mid-facet area for a simplex were established. 相似文献
103.
A general route for preparation of dye-encapsulated polymer particles via an emulsion polymerization process has been described. 1-Naphthaleneboronic acid (NBA) was encapsulated, the resultant particles were used as a fluorescence probe for cilnidipine assay based on fluorescence quenching. The sensitivity of NBA-encapsulated probe to cilnidipine was largely improved in comparison with that of free NBA. The probe showed a linear response toward cilnidipine over the concentration range of 2.0 × 10−7 to 1.1 × 10−5 mol l−1, with high sensitivity, fast response time, and good selectivity. 相似文献
104.
质子交换膜燃料电池波浪形平行流场研究 总被引:1,自引:0,他引:1
质子交换膜燃料电池的传统平行流场存在着传质不佳,高电流密度下大量的液态水无法及时排出导致性能急剧下降等问题。提出了一种新型的波浪形平行流场并利用数值模拟方法优化了波浪形平行流场的几何结构。结果表明,相比于传统平行流场,波浪形平行流场不仅能够有效促进氧气的传输,还能加快液态水的去除,采用波浪形平行流场的PEMFC最大输出功率相比于传统设计提升了30.7%,当波浪长度和波幅分别为4 mm和0.8 mm时,采用新型流场的PEMFC性能达到最佳。 相似文献
105.
Summary For a vector system in En, we establish a class of inequalities for k-dimensional space angle (defined in this paper), and give some application thereof. 相似文献
106.
Composite photocatalysts of CuO/CoFe2O4‐TiO2 were successfully synthesized by a sol‐gel method and fixed on ordinary tiles. The photosterilization of Escherichia coli was examined on CuO/CoFe2O4‐TiO2 thin films under a xenon lamp irradiation. The film was characterized by XRD, and the morphology was observed by SEM. Disinfection data indicated that CuO/CoFe2O4‐TiO2 composite photocatalysts have the much better photocatalytic activity than CuO/CoFe2O4 and TiO2. The optimized composition of the nanocomposites has been found to be mCuO/CoFe2O4:mTiO2=3:7, with loadings ranging from 790 to 1400 mg/m2. The photocatalytic inactivated rate of E. coli (105 CFU/mL) reached 98.4% under the xenon lamp of 150 W within 30 min. 相似文献
107.
Sun Mingbao 《Geometriae Dedicata》2001,85(1-3):119-123
The tangent point simplex of a simplex is the pedal simplex of the incenter of . In this paper we obtain some geometric inequalities between and . 相似文献
108.
掺钇锆酸锶-TiO2复合光催化剂的制备及性能研究 总被引:2,自引:0,他引:2
SrZrO3 particles were prepared by a co-precipitation method and Sr(Zr1-xYx)O3-δ -TiO2 composite particles were then synthesized by Sr(Zr1-xYx)O3-δ and titanium dioxide. The composite particles were characterized by XRD, SEM, FTIR and TG-DTA techniques. The photocatalytic degradation of methylene blue (MB) in aqueous solution was used as a probe reaction to evaluate the photocatalytic activity of the composite particles. The effect of the preparation method for SrZrO3, doping content of yttrium and TiO2 amount in the composite particles on the photocatalytic activity of composite particles was also discussed. The results show that the methylene blue solution could be completely degraded by Sr(Zr1-xYx)O3-δ -TiO2 composite particles under UV-light or visible light irradiation. The photocatalytic activity of composite particles was higher than that of pure TiO2. The fast recombination of photogenerated electrons and holes were restrained by the heterojunction formed in composite particles. The particle of SrZrO3 prepared by co-precipitation was small, and the photocatalytic activity of composite particles prepared from this kind of SrZrO3 was higher than that of particles prepared by solid sintering method. The best doping content of yttrium is 5%. The optimal content of TiO2 in composite particles is 90wt%, 70wt%, respectively under UV-light and visible light irradiation, the degradation rates of MB are 98.8% and 93.5% , respectively after 50 min irradiation. 相似文献
109.
110.