Bi5O7Br and its structural relation to α‐Bi5O7I

Pentabismuth heptoxide bromide, Bi₅O₇Br, crystallizes in the space group Cmca. Its structure is compared with the closely related Ibca structure of α‐Bi₅O₇I. The change in the space group is assumedly the result of a compromise between the different spatial needs of Br and I and the rigidity of the {³_∞}[Bi, O] frameworks into which they are embedded. A detailed procedure for the synthesis of Bi₅O₇Br is given.     

Editorial

The principles of quantum-mechanical measurements are a key issue in the foundation of modern physics. A beautiful consequence of these is the concept of Quantum Nondemolition (QND) measurements. Such measurements permit, in principle, to measure particular observables of a quantum system with unlimited precision, leaving their temporal evolution undisturbed. The application of QND measurements may play an important role in future high-sensivity experiments.Experimental QND measurements require appropriate measurements schemes and apparats, whose development took place in the past few years, thanks to strong progress in ultra-low noise mechanical, electronic and optical detection techniques, coherent light sources, and nonlinear optical systems. At present, interest is focused on measurements of mechanical observables, such as displacement of macroscopic masses and of intensity or phases of electomagnetic field modes in the optical spectral range.This special issue contains original papers on theory and experiments of QND measurements. Recent experimental developments are presented, and proposals and analyses of novel QND schemes are made.The issue focuses on contributions presented at the Workshop on QND Measurements, held March 27–29, 1996, on the Island of Reichenau, Lake Constance (Germany). The workshop was made possible through a generous grant from the Directorats General XII for Sciences, Research and Development of the European Commission.We thank Dr. W. Petrich for his help in preparing this special issue.     

New carbon nanofiber/graphite felt composite for use as a catalyst support for hydrazine catalytic decomposition

Graphite felt supporting 40 nm diameter carbon nanofibers was synthesized and successfully used as a support for a high loaded iridium catalyst (30 wt%) in the decomposition of hydrazine; a strong mechanical resistance and a high thermal conductivity led to a very efficient and stable catalyst as compared to that used industrially, iridium supported on a high surface area alumina.     

X-ray diffraction/Calorimetry coupling

Polymorphism of trilaurin mixed with 4% of cholesterol was studied with a setup coupling calorimetry and phase characterisation by in-situ X-ray diffraction (Microcalix). Four polymorphic forms were identified. Monotropic and enantiotropic transitions were identified from the reconstruction of Gibbs free energy diagram which allows the control of trilaurin polymorphism. This revised version was published online in July 2006 with corrections to the Cover Date.     

Synthese und Kristallstruktur von Blei(II)‐oxidhalogenid‐Alkoholaten mit unterschiedlichen Verknüpfungsvarianten von Pb4O4‐Heterokubaneinheiten

Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb₄O₄ Heterocubane‐like Subunits The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl^? and Br^?) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb₆(C₄H₈O₃)O₂Cl₆] (1) and [Pb₆(C₄H₈O₃)O₂Br₆] (2) . In a similar synthesis with PbI₂ as educt at temperature of 160 °C the two modifications β‐[Pb₆(C₄H₈O₃)O₂I₆] (3) and α‐[Pb₆(C₄H₈O₃)O₂I₆] (4) were found, whereas at a reaction temperature of 180 °C [Pb₉(C₂H₄O₂)(C₄H₈O₃)O₃I₈] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I₆ octahedra centered by lead is observed.     

Amedeo Avogadro The Man, the Hypothesis, and the Number

Amedeo Avogadro was a multifaceted and prolific scientist active in many areas of physics and chemistry, but most of his results did not make a scientific impact. His hypothesis, equal volumes = equal number of molecules remained in obscurity until Cannizaro rekindled it by making it a stepping-stone in the development of the atomic theory.     

All NSR-models in terms of bosonic strings: An explicit derivation

We construct the open and closed string NSR-models in terms ofD15 bosonic string theories. All anticommuting NSR-operators are obtained after fermionizing 4 bosonic dimensions, and the NSR-Hilbert spaces are embedded as linear subspaces of the bosonic Hilbert spaces. We thus show the existence of various 10D supersymmetric sectors of the state spaces ofD=26 consistent bosonic strings.     

Trimethylsilyl-O-methyloxime derivatives for the measurement of [6,6-2H2]-D-glucose-enriched plasma samples by gas chromatography-mass spectrometry.

A new method for the determination of the enrichment of [6,6-2H2]-D-glucose in human plasma by gas chromatography-mass spectrometry (GC-MS) is described. (2,3,4,5,6)-Pentakis-O-trimethylsilyl-O-methyloxime-D-glucose is used as a derivative for the GC measurement. Using GC-MS with electron-impact ionization, the enrichment is measured in the single-ion monitoring mode observing the masses m/z 319 and 321. In contrast to other methods the use of this glucose derivative reduced the amount of plasma needed from 200 to 10 microliters and no chemical ionization equipment is needed for the mass spectrometer.