Simulation of Static and Dynamic Properties of Edge-Emitting Multi Quantum Well Lasers

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Simulation of Static and Dynamic Properties of Edge-Emitting Multi Quantum Well Lasers

This paper demonstrates simulation tools for edge-emitting multi quantum well (MQW) lasers. Properties o

Parameter sensitivity in near-infrared imaging

To model the photon migration in highly scattering media, we use an approximation of the Boltzmann equation, the diffusion equation. A prerequisite for handling the inverse problem consists in solving the forward problem under realistic conditions. We discuss the influence of boundary conditions on the light propagation. The boundary conditions at the walls surrounding the object highly sensitively influence the photon flux at the boundary which means that the time-resolved transmittance is affected. An algorithm for the determination of boundary parameters is introduced and demonstrated by an instructive example. We use the finite element method for the time-resolved case as a basic method in combination with a minimization strategy. The boundary conditions are determined as conditions of the third kind, i.e. the photon density is proportional to the outward photon flux at the boundary

Systematic Classification of LPCVD Processes

A simple classification scheme of low pressure chemical vapor deposition processes is discussed which is based on only three different one-dimensional models of the radial film thickness distribution on silicon wafers processed in a conventional horizontal hot-wall reactor. Comparing theoretical predictions of these models with experimental results obtained from various LPCVD processes, a good qualitative agreement can be stated. For better quantitative accuracy additional effects must be taken into account. The stoichiometrically induced radial flow for deposition reactions not preserving the mole number of involved gaseous species is very important for the parameter evaluation as well as model identification

Acute and Long-Term Hemodynamic Effects of MitraClip Implantation on a Preexisting Secondary Right Heart Failure

Positive results of MitraClip in terms of improvement in clinical and left ventricular parameters have been described in detail. However, long-term effects on secondary pulmonary hypertension were not investigated in a larger patient cohort to date. 70 patients with severe mitral regurgitation, additional pulmonary hypertension, and right heart failure as a result of left heart disease were treated in the heart centers Hamburg and Göttingen. Immediately after successful MitraClip implantation, a reduction of the RVOT diameter from 3.52 cm to 3.44 cm was observed reaching a statistically significant value of 3.39 cm after 12 months. In contrast, there was a significant reduction in the velocity of the tricuspid regurgitation (TR) from 4.17 m/s to 3.11 m/s, the gradient of the TR from 48.5 mmHg to 39.3 mmHg, and the systolic pulmonary artery pressure (PAPsyst) from 58.6 mmHg to 50.0 mmHg. This decline continued in the following months (Vmax TR 3.09 m/s, peak TR 38.6 mmHg, and PAPsyst 47.4 mmHg). The tricuspid annular plane systolic excursion (TAPSE) increased from 16.5 mm to 18.9 mm after 12 months. MitraClip implantation improves pulmonary artery pressure, tricuspid regurgitation, and TAPSE after 12 months. At the same time, there is a decrease in the RVOT diameter without significant changes in other right ventricular and right atrial dimensions

Characterization of Symmetry Properties of Pt(111) Electron Bands by Means of Angle-, Energy-, and Spin-Resolved Photoemission with Circularly Polarized Synchrotron Radiation

Eyers A, Schäfers F, Schönhense G, et al. Characterization of Symmetry Properties of Pt(111) Electron Bands by Means of Angle-, Energy-, and Spin-Resolved Photoemission with Circularly Polarized Synchrotron Radiation. Physical review letters. 1984;52(17):1559-1562.An angle-, energy-, and spin-resolved photoemission experiment has been performed for Pt(111) with the circularly polarized synchrotron radiation of the new German dedicated storage ring BESSY. The photoelectron polarization measured as function of the kinetic energy at different photon energies between 6.5 and 24 eV for normal incidence and normal emission shows a pronounced spectral variation up to +/-55%. The electron intensities and polarizations observed allow a symmetry-resolved band characterization of Pt in the [Gamma]-L direction