Transport of a spherical transparent nanoparticle by radiation forces in the field of a Gaussian laser beam

The motion of a spherical transparent nanoparticle under the influence of radiation forces in the field of a Gaussian laser beam is investigated based on solution of Langevin equation. Expressions governing transverse and longitudinal velocities of the nanoparticle under the action of gradient and scattering forces are derived and analyzed. The possibility of spatial separation of nanoparticles having different sizes and optical properties is discussed.     

Viscoelastic modelling and experimental results of a dielectric electro-active polymer diaphragm actuator

Common actuating principles e.g. solenoids or piezo-elements have mostly exploited their potential as electromechanical transducers. A new technology based on Dielectric Electro-active Polymers (DEAPs) enables major progress in efficiency and functionality for actuators. In order to use the advantages of this new technology in a feasible application, a silicone based DEAP diaphragm actuator was tested experimentally. Here, the mechanical properties of the fundamental parts of the DEAP diaphragm actuator, namely the stressstrain behaviour of an equibiaxially pre-stretched hyperelastic polymer and the mechanical response of a DEAP diaphragm actuator, were determined by appropriate test benches. The investigated DEAP diaphragm actuator consists of a dielectric, which corresponds to a thin elastic silicone film sandwiched between two compliant electrodes. Furthermore, DEAPs are pre-stretched, actually up to five times their in-plane dimensions, in order to improve their performance. In that context, the influence of the pre-stretched state on the actuator performance was investigated. In addition, a viscoelastic finite-element model of the electromechanical system has been developed and validated with the experimental results. The mechanical part of the DEAP diaphragm actuator was realized with an incompressible isotropic elastic model, whereas the electrical part was approximated with a circular parallel-plate capacitor. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

An approximate Lorentz-invariant Hamilton-Jacobi equation

The transformation properties of the nonrelativistic and quasirelativistic Hamilton-Jacobi equations (HJE) are investigated as far as approximate Lorentz invariance is concerned. It is pointed out that these properties depend on whether or not the potential rest energy is included in the particle energy. An approximate Lorentz invariance of the many-particle nonrelativistic HJE is established by means of the multiple time Dirac-Fock-Podolsky formalism.     

O2AIBN,free-radical method for the stereospecific oxidation of nucleoside trialkyl phosphites: new preparation of the individual,diastereomeric, 18O-labeled thymidine 3′, 5′-cyclic monophosphates.

An experimentally easy method for reqio- and stereospecific introduction of isotopic ¹⁸O or ¹⁷O) oxygen into phosphorus di- and triesters of biological interest is described and applied to ¹⁸O-labelinq of cTMP's.     

Asymmetric synthesis of ephedrine analogs

Addition of nitromethane to the chiral chromium tricarbonyl complex of o-tolualdehyde (1) gives, under conditions of kinetic control, the nitroalcohol 2 with 95% of asymmetric induction. Compound 2 then gives, in 3 steps, the corresponding aminoalcohol in about 40% yield. Use of nitroethane gives the nitroalcohol with a small diastereoselectivity at C(2)-C(3) (d.e. = 30 and 55%), but analogs of ephedrine and pseudoephedrine can be obtained optically pure by chromatography.