Influence of a magnetic field on the hydrogen equilibrium pressure of RCo5Hx

The hydrogen equilibrium abessure above a two-phase mixture RCo₅H_x + RCo₅H_y can be changed slightly by applying a magnetic field. For H=10 kOe a relative change Δp/p ≈ 6×10⁻³ has been measured for R=La, x=3.35, y=4.3, T=295 K.     

Enzyme-immunoassay (EIA) of Hepatitis B surface antigen (HBsAg) in microtiter plates

Ohne Zusammenfassung

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Enzyme-immunoassay (EIA) of Hepatitis B surface antigen (HB_sAg) in microtiter plates

     

Expedient synthesis of triazole-linked glycosyl amino acids and peptides

[structure: see text] An expedient, high-yielding synthesis of two types of triazole-linked glycopeptides is described. These novel and stable glycopeptide mimics were prepared via Cu(I)-catalyzed [3 + 2] cycloaddition of either azide-functionalized glycosides and acetylenic amino acids or acetylenic glycosides and azide-containing amino acids.     

Growth and characterization of GaP and GaAs1−xPx

The minority carrier lifetime at low and high excitation densities was determined in VPE layers of GaP and GaAs_?0.2 P_?0.8. The lifetime at high excitation densities, having a value up to ∽350 ns, is one to two orders of magnitude larger than the lifetime at low excitation densities. It is shown that impurities are involved in some saturable killer centres dominating at low excitation densities. In the case of the largest values of the minority carrier lifetime and at a dislocation density of > 10⁵ cm^?2, the non-radiative recombination at high excitation densities is shown to occur at dislocations; at lower values of the minority carrier lifetime the killer action may be due to microprecipitates. These findings also hold for LPE layers of GaP. It is shown that by measuring the minority carrier lifetime as a function of temperature a discrimination is possible between killer action due to diffusion of minorities towards sinks like dislocations or microprecipitates and due to capture by a normal point-defect type recombination centre.     

Reaction Calorimetry for the Development of Ultrasound-Induced Polymerization Processes in CO2-Expanded Fluids

A strong viscosity increase upon polymerization hinders radical formation during an ultrasound-induced bulk polymerization. Since CO₂ acts as a strong anti-solvent for most polymers, it can be used to reduce the viscosity of the reaction mixture. In this work, a process for the ultrasound-induced polymerization in CO₂-expanded fluids has been developed. Temperature oscillation calorimetry has been applied to study the influence of CO₂ on the viscosity during the ultrasound-induced polymerization. In contrast to polymerizations in bulk, the results show that a low viscosity is maintained during polymerization reactions in CO₂-expanded methyl methacrylate (MMA). As a consequence, a constant or even increasing polymerization rate is observed when pressurized CO₂ is applied. Moreover, the ultrasound-induced polymer scission in CO₂-expanded MMA is demonstrated, which appears to be a highly controlled process. Finally, a preliminary sustainable process design is presented for the production of 10 kg/hour pure PMMA (specialty product) in CO₂-expanded MMA by ultrasound-induced initiation.     

Multipole interaction in high energy approximation. Calculation of the total collision cross section

For molecules of cylindrical symmetry the total collision cross section is calculated in the high energy approximation, taking into account various long range intermolecular interactions. Results are obtained for the limiting cases that the rotational motion of the molecules is fast or slow with respect to the duration of the molecular interaction. The assumption is made that either one multipole term of the intermolecular potential predominates or that all multipole terms can essentially be treated as a small perturbation of the van der Waals r^?6 interaction.     

The millimeterwave spectrum of SeO in the XΣ state

The J = 2 ← 1, 3 ← 2, and 4 ← 3 transitions in the three fine structure components of the X³Σ⁻ state of SeO have been measured in a millimeterwave absorption spectrometer. Transitions from the six naturally occurring Se isotopes and in excited vibrational states up to υ = 4 have been observed and have allowed the determination of the isotopic mass and vibrational dependences of the spectroscopic constants.