300MW合缸汽轮机高中压转子现场直轴

300MW合缸汽轮机组的高中压转子是国内目前运行汽轮机的较大转子之一,此类转子轴的直径大、跨距长,校直难度较大。本文论述了华北电科院使用可移动式直轴设备,采用目前较先进的松弛法直轴,在电厂厂房检修场地内成功地完成了某电厂6号机组高中压转子的直轴工作,为机组的抢修节约了时间,其经济效益和社会效益巨大。     

Formulation of ternary complexes of glyburide with hydroxypropyl-β-cyclodextrin and other solubilizing agents and their effect on release behavior of glyburide in aqueous and buffered media at different agitation speeds

Glyburide, a sulfonylurea derivative, widely used as hypoglycaemic agent. In the present study, an attempt has been made to investigate the most effective third component which can be used with hydroxylpropyl-β-cyclodextrin (HPβCd) to form a ternary complex with glyburide in order to enhance its dissolution rate, as well as reduce the amount of HPβCd used for formulating the binary complex with glyburide. Moreover, the objective of this study was also to develop a discriminatory dissolution media in order to discriminate the effect of the different solubilizing agents used for formulating the ternary complex system. Sodium lauryl sulphate, Poloxamer-188, Polyvinylpyrrolidone K-30, lactose and l-arginine were used to formulate ternary system along with HPβCd and glyburide. The ternary system formulated with glyburide:HPβCd:l-arginine in a proportion of 1:1:0.5 has shown the fastest dissolution rate when compared to other solubilizing agents. Unbuffered aqueous media with stirring speed 50?rpm has produced the most discriminatory dissolution profiles. The DSC thermograms and the powder X-ray analysis revealed the decrease in crystallinity of the drug. This was an indication of amorphous solid dispersion or molecular encapsulation of the drug into the cyclodextrin cavity.     

Structural properties of films grown by magnetron sputtering of a BiFeO3 target

Thin films have been prepared on silicon substrates by pulsed DC magnetron sputtering of a BiFeO₃ target under an Ar/O₂ mixture with various oxygen flow (0-50 sccm) at room temperature. Due to the low deposition-temperature, the as-grown films are amorphous. As a consequence, we have investigated the effect of the annealing temperature (400-900 °C) and atmosphere (100% N₂ or 90% N₂/10% O₂) on the crystallisation. Microstructural investigations (XRD, HREM, Raman and FTIR spectroscopy) have been performed in order to determine the structural properties of the films and to establish the experimental parameters leading to BiFeO₃ films. A temperature-dependent Raman study points to a spin-phonon coupling around the Néel temperature.     

Effect of rapid recurrent thermal annealing on the soft magnetic behaviour of Co85.5Nb8.9Zr5.6 nanocrystalline thin films

The rapid recurrent thermal annealing (RRTA) method has been used to crystallize-amorphous Co_85.5Nb_8.9Zr_5.6 soft magnetic thin films, which were fabricated by DC magnetron sputtering onto glass-ceramic substrates directly at room temperature. As a result, crystalline grains with diameter of about 10 nm were formed and a partiall nanocrystallization of the films was obtained. The soft magnetic properties of the Co-based nanocrystalline thin films were largely improved after RRTA. The resistivity is decreased by a quarter and the coercivity is also decreased. The magnetic and electrical properties were investigated using the RRTA method with varied parameters such as annealing temperature, annealing time and repeat cycle. The experimental results revealed that the RRTA is an effective method to control the magnetic and electrical properties of Co_85.5Nb_8.9Zr_5.6 thin films.     

Crystallization kinetics of magnetron-sputtered amorphous CoNbZr thin films

For non-isothermal and isothermal annealing, the crystallization kinetics of magnetron sputtered Co_85.5Nb_8.9Zr_5.6 amorphous alloy thin films have been investigated by differential scanning calorimetry measurements. As a result, in the case of non-isothermal crystallization, one distinct exothermic peak is observed at 470 °C, which is due to the crystallization of hcp α-Co. With the Kissinger method, the apparent activation energy was obtained to be 99.82 kJ/mol. By using the Deloy-Ozawa method, the local activation energy of non-isothermal crystallization was calculated. For isothermal crystallization, the Avrami exponents were determined by means of the Johson-Mehl-Avrami equation, which is in the range of 1.19-1.37. Based on an Arrhenius relationship, the local activation energy was analyzed, which yields an average value E_c=88.51 kJ/mol. Finally, the local Avrami exponent was used for discussing the details of the nucleation and growth behaviour during the isothermal crystallization.     

石墨炉原子吸收法测定螺旋藻粉中的铅和镉

采用微波消解石墨炉原子吸收法测定螺旋藻粉中Pb、Cd。方法的检出限Pb：0．93μg／L,Cd：0．015μg／L,回收率96—108％,RSD小于7．3％。结果表明该方法准确、快速、令人满意。     

Structure evolution on annealing of copper-doped carbon film

Thin copper-doped (8 at.% Cu) carbon film was deposited by direct current magnetron sputtering of composite graphite/copper target in argon plasma. The evolution of film structure on annealing at 600 °C in a vacuum has been studied by transmission electron microscopy and electron diffraction. The as-deposited film was amorphous with copper atoms uniformly distributed over the film volume. Annealing resulted in precipitation of copper particles within carbon film followed by the decrease in the density of copper particles and increase in particle average size with annealing time due to diffusion coalescence within the ensemble of copper particles. The coalescence occurred by the mixed mechanism of bulk and surface diffusion of copper atoms within carbon film that contained a large number of structural defects. As a result, the mean radius of copper particles in ensemble changed as R¯⁵ ∼ t.     

Electrical characteristics and inhomogeneous barrier analysis of Au-Be/p-InSe:Cd Schottky barrier diodes

We have identically prepared Au-Be/p-InSe:Cd Schottky barrier diodes (SBDs) (21 dots) on the InSe:Cd substrate. The electrical analysis of Au-Be/p-InSe:Cd structure has been investigated by means of current-voltage (I-V), capacitance-voltage (C-V) and capacitance-frequency (C-f) measurements at 296 K temperature in dark conditions. The effective barrier heights and ideality factors of identically fabricated Au-Be/p-InSe:Cd SBDs have been calculated from their experimental forward bias current-voltage (I-V) characteristics by applying a thermionic emission theory. The BH values obtained from the I-V characteristics have varied between 0.74 eV and 0.82 eV with values of ideality factors ranging between 1.49 and 1.11 for the Au-Be/p-InSe:Cd SBDs. It has been determined a lateral homogeneous barrier height value of approximately 0.82 eV for these structures from the experimental linear relationship between barrier heights and ideality factors. The Schottky barrier height (SBH) value has been obtained from the reverse-bias C-V characteristics of Au-Be/p-InSe:Cd SBD for only one diode. At high currents in the forward direction, the series resistance effect has been observed. The value of series resistance has been determined from I-V measurements using Cheung’s and Norde’s methods.     

双基体线性敏感陶瓷材料的研究(英文)

重点研究由CdO-SnO2-WO3系列(以下简称Cd-Sn-W)和CdO-Sb2O3-WO3系列(以下简称Cd-Sb-W)及由它们共同组成的双基体三相(Cd2Sb2O7、CdSnO3、CdWO4)结构线性敏感陶瓷的制备方法。给出了上述半导体陶瓷的电子转移式;分析了半导相Cd2Sb2O7和CdSnO3的导电机理和电阻-温度(R-T)曲线呈线性的机理,并对其他特性进行了深入的分析和研究。