High gain in hybrid transistors with BAlq(3)/Alq(3) isotype heterostructure emitter

We report the fabrication of permeable metal-base transistors based on bis(2-methyl-8-quinolinolato-N1,O8)-(1,1'-biphenyl-4-olato) aluminum (BAlq(3))/tri(8-hydroxyquinoline) aluminum (Alq(3)) isotype heterostructure as emitter layer. In this transistor, n-Si was used as the collector, LiF/Al as the emitter electrode, and Au/Al bilayer metal as the base. We show that the leakage current is greatly reduced in Al/n-Si/Au/Al/BAlq(3)/Alq(3)/LiF/Al devices with respect to Al/n-Si/Au/Al/Alq(3)/LiF/Al devices due to the utilization of BAlq(3)/Alq(3) isotype heterostructure emitter, leading to high common-base and common-emitter current gains at low driving voltages.

Polymerization of 1,3-butadiene with VO(P-204)(2) and VO(P-507)(2) activated by alkylaluminum

The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.

Determination of ultra-trace concentrations of elements in high purity tellurium by inductively coupled plasma mass spectrometry after Fe(OH)(3) coprecipitation

In this work, a method was established for the determination of impurities in high purity tellurium by inductively coupled plasma mass spectrometry (ICP-MS) after Fe(OH)(3) coprecipitation. After comparison of coprecipitation ability and separation efficiency between Fe(OH), and Al(OH)(3), Fe(OH)(3) was chosen as the precipitate. A separation factor of 160 for 200 mg tellurium was obtained under conditions of pH 9 and 2 mg of Fe3(+). The 13 elements, such as Bi, Sn, Pb, In, Tl, Cd, Cu, Co, Ni, Zn, Ti, Be and Zr, could be almost completely coprecipitated under these conditions. In addition, Te memory effect imposed on the ICP-MS instrument was assessed, as well as Te matrix effect that caused the low recovery of Ga, As, Sb and V in real sample was discussed. Finally, the method was evaluated through recovery test and was applied to practical sample analysis, with detection limits of most of the elements being below 0.15 mug g(-1) and R.S.D. below or at approximately 10%, which indicated that this method could fully satisfy the requirements for analysis of 99.999% similar to 99.9999% high purity Te.

CoMoK／γ－Al_2O_3水煤气变换催化剂的硫化及反硫化

以Ｈ＿２Ｓ和ＣＳ＿２作硫化剂，用ＴＰＳ和ＴＰＤＳ方法研究了水媒气变换催化剂ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３的硫化及反硫化过程。用Ｈ＿２Ｓ／Ｈ＿２硫化时，只发现Ｈ＿２Ｓ的消耗和Ｈ＿２Ｏ的生成，用ＣＳ＿２／Ｈ＿２硫化时，首先生成ＣＯ＿２，然后是ＣＨ＿４，Ｈ＿２Ｏ和Ｈ＿２Ｓ，ＴＰＧ实验表明催化剂表面上有积炭，造成催化剂的活性降低。但积炭在水煤气变换反应进行中逐渐除去。ＴＰＤＳ实验表明Ｎ＿２不起反硫化作用，Ｈ＿２和ＣＯ也没有明显反硫化作用，Ｈ＿２Ｏ对ＣｏＭｏＫ／γ－Ａｌ＿２Ｏ＿３催化剂有根强的反硫化作用。Ｏ＿２能使催化剂部分永久性失活。ＸＰＳ测试表明反硫化的催化剂中低价的Ｍｏ￣（４＋）转变成高价的Ｍｏ￣（５＋）和Ｍｏ￣（６＋），导致其活性下降。

青藏高原3种秦艽组植物微量元素比较分析

利用全谱直读等离子体发射光谱法（ICP—AES）测定了3种秦艽组植物10种微量元素（Cu，Zn，Fe，Mn，Ni，Co，Sn，V，Al，Ti）的含量，并进行了比较分析。结果表明，所测定元素在3个不同物种内的含量排列顺序基本一致，显示了三者在元素富集方面的相似性。就同一种元素在3个物种内的富集水平而言，以麻花艽根部具有较高含量的元素Cu，Zn，Co，Al和Ti，管花秦艽根部则大量富集了其余5种微量元素，达乌里秦艽对元素的吸收积累能力居中，揭示了不同物种对同一元素富集能力的差异。该研究可为秦艽类植物资源的深入开发利用提供参考。