Subsurface layers with degenerate hole gas arising in germanium immersed into liquid helium under 60Co-gamma irradiation

Abstract

The subsurface layers with quasi-metal hole conductivity have been observed in n- and p-Ge immersed into liquid He under the ⁶⁰Co-gamma-irradiation. three conditions are to be fulfilled simultaneously for the production of the layers: low temperature, direct contact between helium and germanium and gammairradiation.     

Towards peptide-substituted titanocene anticancer drugs

An alkyne-substituted fulvene was transformed via hydridolithiation followed by transmetallation with titanium tetrachloride into bis-[p-(prop-2-ynyloxy)-benzyl-cyclopentadienyl] titanium(IV) dichloride. Single crystals of this titanocene derivative could be obtained and the structure determined by X-ray diffraction. It showed that this compound crystallises in the space group C2/c with four molecules in the monoclinic cell. The alkyne-substituted titanocene dichloride derivative was then subject to a copper-catalysed azide-alkyne cycloaddition with its azide-functionalised methylester-protected phenylalanine reaction partner in order to form a linking triazole. This reaction was performed under anhydrous conditions employing a dichloromethane/acetonitrile solvent mixture with copper(I) iodide and 2,6-lutidine as the catalyst system. Under these conditions the adduct between the protein mimic and the titanocene was formed without hydrolysing the titanium dichloride moiety.     

Synthesis and characterization of coordination compounds of organotin(IV) with nitrogen and sulfur donor ligands

The reactions of dimethyltin dichloride with nitrogen and sulfur donor ligands derived by condensation of S‐benzyldithiocarbazate with indol‐3‐carboxylaldehyde, thiophene‐2‐aldehyde and furfuraldehyde have been investigated in 1:1 and 1:2 molar ratios in anhydrous alcohol. These ligands act as mononegatively charged bidentate species and coordinate to the central tin(IV) atom through the thiosulfur by proton exchange with the azomethine nitrogen. The newly synthesized complexes have been characterized by elemental analysis, conductance measurements and molecular weight determinations. The mode of bonding and the geometry of the complexes have been suggested on the basis of infrared, electronic and ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy, and probable structures have been assigned to these complexes. A few representative ligands and their tin(IV) complexes have also been screened for their antifungal and antibacterial activities and found to be quite active in this respect. Copyright © 2001 John Wiley & Sons, Ltd.     

黄芩中锗的分光光度研究

对黄芩中的锗进行了分光光度法研究，结果表明，黄芩中含有丰富的有机锗。本方法简单可靠，可获得满意的分析结果。     

Accurate and analytical strain mapping at the surface of Ge/Si(0 0 1) islands by an improved flat-island approximation

We propose an extension of the well-known flat-island approximation in (1 + 1) dimensions which, while keeping simple analytical relations, allows one to better describe the strain field on the facets of steeper islands, and on the wetting layer between them. The results of atomistic molecular dynamics simulations using the Tersoff potential are used as a benchmark. The simple continuum approach is also shown to predict the correct trend of the strain gradients characterizing closely-spaced interacting islands, which has been recently observed to produce lateral motion of large Ge dots on Si(0 0 1).     

人参中锗的分光光度法测定

采用灰化法分解人参样品，用分光光度法测定人参中的有机锗含量，方法简便，快捷，回收率为98．90％－99．78％。     

Magnesium chloride modified with organoaluminium compounds as a support of the zirconocene catalyst for ethylene polymerisation

This work describes the influence of the modification of the MgCl₂(THF)₂ and MgCl₂ magnesium supports with the AlEt₂Cl, MAO, AlEt₃, AlMe₃, and AlEt₂Cl alkylaluminium compounds on heterogenisation of the bis(cyclopentadienyl) zirconium(IV) dichloride Cp₂ZrCl₂ catalyst. It was found that only the MgCl₂(THF)₂ support modified with AlEt₂Cl gave the heterogeneous catalyst. On the contrary, application of a magnesium carrier modified by AlEt₃, AlMe₃, and MAO compounds only results in a homogeneous zirconocene catalyst.