微波烧结Al_2O_3陶瓷的研究

简要介绍了微波烧结的特点,对 Ａｌ２ Ｏ３ 陶瓷的微波烧结过程进行了介绍和分析,并同常规烧结进行了对比实验,在此基础上得出了一些结论,为陶瓷微波烧结提供了实验依据     

Effect of the stoichiometry on the electronic structure of the Ni（111）/α-Al2O3（0001） interface： a first-principles investigation

In this paper first-principles calculations of Ni（111）/α-Al2O3（0001） interfaces have been performed, and are compared with the preceding results of the Cu （111）/α-Al2O3（0001） interface [2004 Phil. Mag. Left. 84 425]. The AI- terminated and O-terminated interfaces have quite different adhesion mechanisms, which are similar to the Cu（111）/α Al2O3（0001） interface. For the O-terminated interface, the adhesion is caused by the strong O-2p/Ni-3d orbital hybridization and ionic interactions. On the other hand, the adhesion nature of the Al-terminated interface is the image-like electrostatic and Ni-Al hybridization interactions, the latter is substantial and cannot be neglected. Charge transfer occurs from Al2O3 to Ni, which is opposite to that in the O=terminated interface. The charge transfer direction for the Al-terminated and O-terminated Ni（111）/α-A1203（0001） interfaces is similar to that in the corresponding Cu（111）/α- Al2O3（0001） interface, but there exist the larger charge transfer quantity and consequent stronger adhesion nature, respectively.     

Li_4SiO_4陶瓷小球水解吸行为实验研究

采用程序升温热解吸(TPD/TDS)方法对Li4SiO4陶瓷小球的水解吸行为进行了实验研究。结果表明:水解吸过程中主要存在四个解吸峰;其中100℃附近的峰可解释为物理吸附水;150,250,400℃附近的峰可分别解释为以氢键、Li-OH和Si-OH配位键形式存在的化学吸附水。氚的释放与水的解吸几乎同步进行,且氚的释放形式主要为氚水(HTO),据此推测,氚水可能存在三种释放机制:(1)-OT+H2O→-OH+HTO;(2)-OH+-OH→H2O,-OT+H2O→-OH+HTO;(3)-OT+-OH→HTO。     

Investigation on the scattering effect of ceramic Nd:YAG

This paper investigates the scattering effect of domestic 0.5 at{\%} ceramic Nd:YAG. An effective method has been utilized to measure the scattering and absorption coefficients. An end-pumped continuous wave (CW) Nd:YAG ceramic laser was also demonstrated. A maximum output power of 6.7~W at 1064~nm was obtained at an 808-nm pump power of 32.9~W. Conversion efficiency and slope efficiency have been achieved. This indicates that scattering has an important effect on the optical performance of ceramic Nd:YAG.     

爆电换能脉冲大电流输出研究

 基于爆电换能原理,使用掺铌的PZT 95/5陶瓷组装换能器件,在垂直工作模式下,对爆电电源LRC电路响应进行了理论分析,并开展了脉冲大电流输出实验研究。实验采用多组PZT 95/5铁电陶瓷并联,利用平面波发生器作为冲击加载手段,获得了峰值5 kA以上的脉冲大电流,初始电流上升速率可达10~20 GA/s。实验结果与理论设计符合较好。     

Highly transparent cerium doped gadolinium gallium aluminum garnet ceramic prepared with precursors fabricated by ultrasonic enhanced chemical co-precipitation

Cerium doped gadolinium gallium aluminum garnet (GGAG:Ce) ceramic precursors have been synthesized with an ultrasonic chemical co-precipitation method (UCC) and for comparison with a traditional chemical co-precipitation method (TCC). The effect of ultra-sonication on the morphology of powders and the transmittance of GGAG:Ce ceramics are studied. The results indicate that the UCC method can effectively improve the homogenization and sinterability of GGAG:Ce powders, which contribute to obtain high transparent GGAG ceramic with the highest transmittance of 81%.     

低温烧结NaBi(WO4)2陶瓷的介电性能

采用固相合成法制备了（WO₄）₂（NBW）陶瓷，研究了NBW陶瓷的相结构、形貌、烧结特性和微波介电性能。NBW陶瓷在625~800℃烧结1~4 h能够致密化。X射线衍射表明在625~800℃烧结2 h的NBW陶瓷均为四方晶系白钨矿结构的单相陶瓷。随着烧结温度的提高，NBW陶瓷的介电常数、品质因数（Qf值）先增加后降低，谐振频率温度系数逐渐降低。经650℃烧结2 h获得的NBW陶瓷的介电常数为14.36，Qf值为16 503 GHz，谐振频率温度系数为-1.055×10-5℃^-1。NBW陶瓷与银共烧反应生成Ag₂W₂O₇相，而与Au、Al共烧具备化学兼容性。     

Testifying experiment of the multi-pulse phenomena of capillary discharge soft-X-ray laser

In a capillary discharge experiment for the neon-like argon lasing, we have proposed an experimental scheme to verify that the multi-spike of X-ray diode (XRD) signal is a multi-pulse laser or is a reflection of the laser pulse in the XRD.The ceramic capillary has an inner diameter of 3mm and a length of 200mm.At the gas pressure of 28Pa and discharge current of 27kA, stable lasing has been realized.The experimental results prove that the multi-spike of XRD signal is a reflection of the electromagnetic signal produced by the laser pulse in the XRD.The improved electrocircuit scheme of the XRD to minimize the reflection phenomena is also found.     

Preparation and Characterization of Ceramic Hollow Microspheres for Heavy Metal Ion Removal in Wastewater

Ceramic hollow microspheres (CHMSs) were prepared to use as supports for the removal of heavy metal ions from industrial waste-water. A water extraction sol–gel technique was used to prepare porous CHMS by extracting water from an emulsion of LUDOX (silica colloid; SiO₂, Aldrich Co.) and 2-ethyl-1-hexanol. Experiments were conducted to control pore size, wall thickness, and separation yield by examining the ratio of precursors (LUDOX and 2-ethyl-1-hexanol), catalyst (NH₄OH), sintering temperature, surfactant (SPAN 80), extractant (n-butanol), stirring speed, and concentration of precursor (LUDOX). The results revealed that the optimum conditions were 20 ml of a 10 wt% solution of LUDOX, 10 ml of NH₄OH, a sintering temperature of 500°C, 0.4 ml of SPAN 80, 200 ml of n-butanol, and a stirring speed of 730 rpm/100 ml of 2-ethyl-1-hexanol. CHMSs were impregnated in Cyanex 272 and examined for their ability to remove heavy metal ions from a solution. Based on an experiment involving the removal of metal ions using CHMSs that were prepared under optimum conditions, Zn ion was removed at a level of 0.354 mmol/g at pH 4, which was about twice the adsorption capacity of CHMSs prepared by Wilcox (Mater. Res. Soc. Symp. Proc.346, 201 (1994)).     

低压微位移驱动电路及控制方法

讨论了低压微位移驱动电路及控制方法在光电轮廓仪上的运用。采用低压驱动电路驱动压电陶瓷相移器对参考光束进行相移，从而使仪器质量减轻、体积缩小、成本降低。在运用该电路时，为了解决压电陶瓷低电压区非线性误差大的问题，用PC计算机控制压电陶瓷上所加电压的电压值，由摄像头摄取图像并计算出干涉条纹的间隔，然后由PC计算机修改压电陶瓷上所加的电压值，直至干涉条纹相位差达到要求值。该方法的优点是：可消除压电陶瓷低压区的非线性误差，使得开环电路得到闭环的效果；可降低机械零部件的装配难度。