Light scattering in a number of optical grade glasses

Light scattering measurements have been made on a number of commercially available optical grade glasses. By measuring the spectrum as well as intensity of the scattered light it was found possible both to obtain the total scattered intensity and to identify the origin of the scattering. The optical attenuation coefficient due to scattering was evaluated. It was found that in all glasses studied the total scattered intensity exceeds that in fused silica by at least a factor of two.     

The Responsibility of the Scientist

The tradition of mutual trust between science and the public appears to have been broken in recent years. It is necessary to define the boundaries of science and to reflect upon the responsibility of the scientist.     

Asymmetrische Photodimerisierung in kristallinen Cyclohexyliden-Oxazolonen

Ohne Zusammenfassung

---

Asymmetric photodimerization in crystalline cyclohexylidene oxazolones

     

Self-energy radiative corrections in hydrogen-like systems

The one-photon self-energy radiative level shift of an electron in a Coulomb field is examined. An expression for the level shift which is suitable for direct numerical evaluation, for Z in the range 10–110, is obtained. It is based on the known Coulomb radial Green's functions and not on a power series expansion in Zα. In the following paper, the numerical evaluation of the level shift for the $\text{1S}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state is described.     

Calculation of QED Effects in Hydrogen

Atomic mass differences are influenced by QED corrections, and a reliable understanding of these corrections is therefore of importance for the current and next generation of high-precision mass determinations based on Penning traps. We present a numerical evaluation of the self-energy correction, which is the dominant contribution to the Lamb shift, in the region of low nuclear charge. Our calculation is nonperturbative in the binding field and has a numerical uncertainty of 0.8Hz in atomic hydrogen for the ground state and of 1.0Hz for L-shell states (2S_1/2, 2P_1/2, and 2P_3/2). This revised version was published online in July 2006 with corrections to the Cover Date.     

Microwave bonding of poly(methylmethacrylate) microfluidic devices using a conductive polymer

Component binding within microfluidic devices is a problem that has long been seeking a solution. In this investigation, the use of microwave radiation to seal PMMA components has been investigated using polyaniline as an absorber that is capable of inducting interfacial bonding. Straight microchannels were machined into PMMA using a Datron CAT3DM6 CNC machine with widths and depths across a range of 100-1000 μm. Prototype fluidic devices were prepared with channel patterns utilizing varying feature sizes, bends and flow profiling to demonstrate the application of the technique to real microfluidic devices. Experimental data illustrated the successful bonding of channels in the range stated previously and bonding (tensile) strength was assessed via pull tests on bonded PMMA using an Engstrom Zwick 100 tensile testing system (Engstrom Ltd, US). Coherent, defect free seals were attained with breakage tests requiring an excess of 1 kN force.