Growth and characterization of Si doped vapor phase epitaxial GaAs for mesfet

This paper describes the Si-doping of GaAs that was grown using the AsCl₃:H₂:GaAs, Ga Chemical vapor deposition process. The doping sources were AsCl₃:SiCl₄ liquid solutions which proved to be highly reproducible for Si doping within the range, 1×1O¹⁶ to 2×10¹⁹ cm^?3. Incorporation of Si into the GaAs apparently occurs under near equilibrium conditions. This point is considered in detail and the consequences experimentally utilized to grow n, n+ bilayers using a single AsCl₃:SiCl₄ doping solution. Si impurity profiles based upon differential capacitance and SIMS data are presented. These can be very abrupt for n, n⁺ structures with order of magnitude changes occurring within 500 Å. For the 1×10₁₆ to 8×l0¹⁸ cm^?3 doped samples the mobilities at 78 and 298°K are comparable to the higher values reported for GaAs thin films grown by CVD. Power FET devices made from this material have demonstrated an output density of 0.86 watts/mm at 10 GHz.     

Preparation of SnO2 whiskers via the decomposition of tin oxalate

A new method for preparing SnO₂ whiskers by the decomposition of SnC₂O₄ is suggested. A Whisker-like morphology of a SnC₂O₄ precipitate was attained via the gradual addition of an oxalic acid solution to a hot SnCl₂ aqueous solution (T > 50^∘C). In comparison, when the solution temperature was either lower than 50^∘C or when ethanol was used as the solvent, the SnC₂O₄ precipitate showed an angular and relatively isotropic morphology. The morphology of the SnC₂O₄ precipitate remained even after its thermal decomposition into SnO₂ at 400^∘C indicating that SnC₂O₄ precipitation is a key step in preparing the whiskers. The formation mechanism of SnO₂ whiskers was explained by the supersaturation during the precipitation of SnC₂O₄.     

一种环保化学储能电池——钒氧化还原液流电池

可再生能源需要性能优良的储能电池与之配套，因此，研究和开发价廉、高效率的储能系统是十分必要的。本文通过介绍钒氧化还原液流电池的原理和特点，指出钒电池是一种潜力巨大的新型环保储能电池。同时介绍钒电池制备和应用时的三大技术关键及一定的解决方法。     

Energy transfer mechanism of GdPO4: RE3+ (RE = Tb, Tm) under VUV-UV excitation

Polycrystal of GdPO₄:RE³⁺ (RE=Tb, Tm) phosphors were prepared by solid-state method. Vacuum ultraviolet excitation and emission spectrum and the energy transfer mechanism between the host and dopants of Tb³⁺ and Tm³⁺ were investigated respectively. The emission of Gd³⁺ at 313 nm was enhanced by the strong absorption of CTS of Tm³⁺ at 180 nm in GdPO₄: Tm. It has also been concluded that the excitation of Gd³⁺ is transferred to Tb³⁺ and then emission peaks of ⁵D_J→⁷F_J of Tb³⁺ were observed.     

1-吡啶-3-[4-(苯基偶氮)苯基]-三氮烯与汞的显色反应及其应用

在Triton X-100存在下的pH 10的Na2B4O7-NaOH缓冲介质中,研究了1-吡淀-3-[4-(苯基偶氮)苯基]-三氮烯(PYPAPT)与汞离子(Hg2 )的显色反应,建立了微量汞的测定方法。Hg2 与PYPAPT形成1∶2的红色络合物,络合物最大吸收波长位于518 nm,表观摩尔吸光系数为1.42×105L.mol-1.cm-1,Hg2 质量浓度在0~0.64 mg/L范围内符合比尔定律。方法用于铅锌矿样中微量汞的测定,RSD小于2.6%,测定结果与AAS法相符。     

氮化硅晶须的研究现状

介绍了晶须的生长机理、氮化硅晶须的制备方法以及影响其生长的因素。阐述了氮化硅晶须增强复合材料的现状,指出加强晶须的基础研究,改进制备技术和降低成本是今后的发展方向。     

Characterization of (Y,Gd) BxV1-xO4-x:Eu Phosphor Prepared by Coprecipitation Reaction

White body-color (Y, Gd)BxV1- xO4-x :Eu3 phosphors were prepared by coprecipitation reaction. Under VUV excitation at 147 nm, the red emission colorimetric purity of (Y, Gd)BxV1- xO4-x :Eu3 phosphor is much better than that of commercial PDP (plasma display panels) phosphor (Y, Gd)BO3:Eu3 . But its relative emission intensity is only about 90% of the commercial phosphor.     

Research on Poly （Styrene-Crylicacid）-Suported Neodymium Complex Catalytic Copolymerization of Styrene and 4-Vinylpyridine

Research on Poly(Styrene-Crylicacid)-Suported Neodymium Complex Catalytic Copolymerization of Styrene and 4-Vinylpyridine     

含3-三氟甲基的均三唑并[3,4-b]-1,3,4-噻二唑类化合物的合成

以 3-三氟甲基 - 4-氨基 - 5 -巯基 - 1 ,2 ,4-三唑为原料 ,分别与 2 - ,3- ,4-吡啶甲酸及α-萘乙酸在 POCl3催化下反应 ,制得 4种新的 3-三氟甲基 - 6-取代均三唑并 [3,4- b]- 1 ,3,4-噻二唑( 3a～ 3d) ,并利用 EA,IR,1H NMR等确定了其结构     

Zr-4合金板α相高温区轧制的织构演化

用(0002)正极图和织构取向因子等方法,研究了a相高温区沿原板材的轧向和横向轧制63%的Zr-4合金板的织构。实验结果表明:Zr-4合金板材在a相高温区轧制后的织构与原料板材的织构有关,这是由它的形变机制决定的。Zr-4合金板在a相高温区轧制时,{10`11}<`2113>和{11`21}<`2113> 锥面滑移是主要的形变系统,所以轧制后形成基极取向集中于轧面法向的织构。沿原始板材的轧向进行轧制时,部分晶粒中的{`1010}<`12`10>柱面滑移开动,使轧制后的ft大于fl;沿原始板材的横向进行轧制时,{11`21}<`1`126>孪生的作用使基极沿轧面法向上的取向增强。