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The development of commercial millimeter wave systems requires cost-effective, high-performance device/circuit assembly techniques. A solder-free thermosonic bonding approach is described here to integrate millimeter wave high-power devices with associated planar circuitry. The devices with integrated heatsink are attached to a metal block, and then ribbon bonded with planar millimeter-wave transmission line circuitry using the developed solder-free thermosonic bonding process. The assembly process is designed to minimize the stresses that damage the devices, while maintaining the bond integrity. Observations confirm that the introduction of ultrasonic energy into the bonding process significantly reduces the temperature and assembly force applied to the device. The effects of different assembly parameters on the performance of the device are also presented. [ABSTRACT FROM AUTHOR]

This report provides a brief review of the 20th annual meeting of the German Language Branch of the Society of Environmental Toxicology and Chemistry (SETAC GLB) held from September 7th to 10th 2015 at ETH (Swiss Technical University) in Zurich, Switzerland. The event was chaired by Inge Werner, Director of the Swiss Centre for Applied Ecotoxicology (Ecotox Centre) Eawag-EPFL, and organized by a team from Ecotox Centre, Eawag, Federal Office of the Environment, Federal Office of Agriculture, and Mesocosm GmbH (Germany). Over 200 delegates from academia, public agencies and private industry of Germany, Switzerland and Austria attended and discussed the current state of science and its application presented in 75 talks and 83 posters. In addition, three invited keynote speakers provided new insights into scientific knowledge 'brokering', and-as it was the International Year of Soil-the important role of healthy soil ecosystems. Awards were presented to young scientists for best oral and poster presentations, and for best 2014 master and doctoral theses. Program and abstracts of the meeting (mostly in German) are provided as Additional file 1.

A numerical procedure that uses an explicit finite difference method to solve the wave equation is described. This technique results in a propagation algorithm that can accurately propagate an arbitrary electric field through a uniform medium or a medium that is nonuniform, transversely flowing, saturable, and contains index inhomogeneities. By using the propagation algorithm to propagate an arbitrary field back and forth between two resonator mirrors, the three-dimensional transverse mode and the output beam characteristics for a laser resonator can be determined. The advantage of the finite difference method is that unlike integral techniques the computational accuracy and efficiency improve as the resonator Fresnel number increases. The computational techniques are explained, and results for several specific empty cavity confocal unstable resonators are presented and compared to results obtained using an established calculation technique. The application of the finite difference method to inhomogeneous laser media is described, and computational results for an existing CO(2) gas dynamic laser are presented and compared to measured data. The medium kinetics and shock wave models used in the calculations are described.

Laboratory measurements using a stabilized CO(2) laser and a 1-km long path absorption cell are presented here for pure water vapor and water vapor-air mixtures. An empirical extinction coefficient equation is presented and used to compute absorption for a variety of atmospheric slant paths. Finally, the laboratory results are confirmed by comparison with outdoor transmission studies over a 1.95-km path.

Theoretical calculations using continental, fog, and precipitation aerosol size distribution models are presented here for extinction and backscatter coefficients along horizontal propagation paths at sea level. The coefficients are presented for various atmospheric conditions and for wavelengths between 0.34 micro and 10.6 micro. Finally, the theoretical results are confirmed by comparison with outdoor transmission studies at 10.6 micro and 0.63 micro.

A theoretical investigation has been undertaken to study the transverse modes of two-dimensional positive branch, confocal unstable resonators. Mode amplitude and phase information is obtained from a numerical-iterative type calculation that uses the Fresnel integral for propagating the cavity radiation back and forth between resonator mirrors. Near- and far-field distributions for empty cavity resonators are presented for various resonator Fresnel numbers and magnifications, along with results of resonator mode stability and diffraction losses when cavity perturbations such as mirror misalignment and/or a uniformly saturable gain medium are included. In addition, the diffractive calculations are compared with results obtained from geometric models.