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161.
采用共沉淀法制备了高钛含量的复合氧化物TiO2/SiO2.用BET、XRD、FT-IR和正胺吸附等分析手段,研究了煅烧温度对TiO2/SiO2表面酸量的影响.研究发现,随着煅烧温度的升高,TiO2/SiO2表面羟基密度、比表面积逐渐减少,TiO2晶粒尺寸变大,造成TiO2/SiO2表面酸量降低.当煅烧温度达到600℃到800℃之间,表面酸量基本不再改变. 相似文献
162.
Łada T. Przybylski K. Morawski A. Prażuch J. Brylewski T. 《Journal of Thermal Analysis and Calorimetry》2001,64(2):611-615
The fabrication method of superconducting thin films of compositions HgBa2Ca2Cu3O8+δ (Hg-1223) and Tl2Ba2CuOy (2201) on single-crystalline SrTiO3 and LaAlO3 substrates is reported. The highest obtained T
c was 134 K and J
c over 106 A cm–2 at 77 K. High pressure DTA(HP-DTA) was applied to grow mercury- and thallium-based high-temperature superconducting crystals
and thin films, to identify melting points of particular phases within these oxide systems and determine suitable processing
conditions. The DTA system operates at the: maximum temperature of 1200°C, volume up to 5 cm3, working pressure up to 1.5 GPa and at a working atmosphere — inert gas with up to 25% oxygen.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
163.
Kasani Aparna Professor Setharampattu S. Krishnamurthy Munirathinam Nethaji 《无机化学与普通化学杂志》1995,621(11):1913-1921
Lanthanide nitrate complexes of diphosphazane dioxides Ph2P(O)N(Pri)P(O)Ph2 ( 1 ) and (PhO)2P(O)N(Me)P(O)(OPh)2 ( 2 ) have been synthesised and studied by conductometry, IR, multinuclear NMR spectroscopic methods and X-ray diffraction. Ligand 2 is accessible by two different methods, viz., by direct oxidation of the phosp(III)azane ligand or by starting from phosph(V)azane chloro precursor. The structure of 2 is confirmed by X-ray diffraction. Crystallographic data for 2 : Triclinic, Space group P1 , a = 10.078(1), b = 10.575(3), c = 12.364(4) Å, α = 75.70(2)°, α = 75.56(1)°, γ = 77.68(1)°, Z = 2, V = 1 220 Å3; structure refined to RF = 0.0459 on 3 495 data with F > 3σ(F). The diphosphazane dioxide ligand exhibits trans geometry in the solid state. The structure of a lanthanide complex, [Pr(NO3)3( 2 )2] ( 14 ) is also determined by X-ray diffraction. Crystallographic data for 14 : Trigonal, Space group P32, a = b = 15.710(2), c = 40.067(2) Å, Z = 6, V = 8 564 Å3; structure refined to RF = 0.0430 on 8 077 data with F > 5σ(F). The two diphosphazane dioxide ligands and the nitrate groups are coordinated to praseodymium in a bidentate chelate fashion. The geometry around the ten coordinated metal is distorted bicapped square antiprism. 相似文献
164.
Vladislav?Tomi?i?Email author Vjekoslav?Butorac Jadranka?Viher Vladimir?Simeon 《Journal of solution chemistry》2005,34(6):613-616
The effect of temperature on the π∗←π transition band in the UV absorption spectrum of NO3−(aq) centered at ≈200 nm was studied in the temperature range 10–70 ∘C. The observed temperature independence of this band was in contrast to the significant influence of temperature on the nitrate π∗←n transition reported recently by us. However, taking into account the electronic states involved in both the transitions, it was concluded that this finding was in accordance with our previous assumption that interconversion between spectrally distinct (with respect to π∗←n band) nitrate species included the rupture/formation of hydrogen bond(s) in the hydration shell of the nitrate ion. 相似文献
165.
166.
一步室温固相化学反应合成纳米氨基酸杂多电荷转移配合物(HPhe)3PMo12O40·2H2O 总被引:3,自引:0,他引:3
以Keggin结构的钼磷酸(H3PMo12O40·13H2O)与苯丙氨酸(Phe)为原料,利用一步固相化学反应于室温合成了纳米氨基酸杂多电荷转移配合物(HPhe)3PMo12O40·2H2O,采用元素分析,IR,XRD,TEM,UV和循环伏安法等手段对其进行了结构表征及性质研究.结果表明,标题化合物纳米粒子为均匀的球状,粒径约为30~40nm.该化合物中杂多阴离子部分仍保持Keggin结构,但在钼磷酸与苯丙氨酸之间发生了显著的电荷转移. 相似文献
167.
Improved separations of the isomers of olefinic aliphatic insect pheromones were obtained on cholesteryl cinnamate glass capillary columns by operating in the supercooled temperature range of the liquid crystal. Capillary columns were prepared with varying film thickness of the stationary phase; choice of the correct film thickness ensured optimum retention for a wide range of compounds within the most effective temperature range of the liquid crystal. The deactivation procedures described made the liquid crystal columns suitable for separation of the geometric isomers of polar and nonpolar compounds. 相似文献
168.
169.
170.
Thanner H. Krempl P. W. Selic R. Wallnöfer W. Worsch P. M. 《Journal of Thermal Analysis and Calorimetry》2003,71(1):53-59
Quartz-homeotypic gallium (ortho-) phosphate, GaPO4, is of special interest for resonator applications asking for temperature compensated cuts with higher electro-mechanical coupling than quartz and operational temperatures up to 970°C. The crystal microbalance technique, well known for quartz (QCM) which can be used only at moderate temperatures, can now be extended to much higher temperatures using GaPO4 crystals, benefiting from all three advantages mentioned above. Two different experiments were done to demonstrate the advantages of a crystal microbalance based on GaPO4. First, the GaPO4 resonator was used for film thickness determination and compared with a commercial QCM. This experiment demonstrated that the measuring range can be extended by using GaPO4 resonators instead of quartz. The second experiment demonstrates the possibility for thermogravimetric analysis up to 720°C by using a new concept for resonator mounting.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献