A5063662478- solar cell performance optimization
- Spectroscopy and Laser Applications
- X-ray Diffraction in Crystallography
- Silicon and Solar Cell Technologies
- Sensor Technology and Measurement Systems
- Scientific Measurement and Uncertainty Evaluation
- Solar Thermal and Photovoltaic Systems
- Metal and Thin Film Mechanics
- Nuclear Physics and Applications
- Orthopaedic implants and arthroplasty
- Orthopedic Infections and Treatments
- Advanced ceramic materials synthesis
- Molecular Junctions and Nanostructures
- Photovoltaic System Optimization Techniques
- Copper Interconnects and Reliability
- Atmospheric and Environmental Gas Dynamics
- Heat Transfer and Boiling Studies
- Nuclear materials and radiation effects
- Neural Networks and Applications
- Advanced Sensor Technologies Research
- Thermodynamic and Structural Properties of Metals and Alloys
- Inertial Sensor and Navigation
- Organic Electronics and Photovoltaics
- Boron and Carbon Nanomaterials Research
- Optical Coatings and Gratings
Physikalisch-Technische Bundesanstalt
2013-2023
Universität Hamburg
2014-2018
Hamburg University of Technology
2014-2018
Carl von Ossietzky Universität Oldenburg
2013
Karlsruhe Institute of Technology
2008
Nokia (United States)
2003
Franklin Institute
1962-1965
Evaporated films may have different thermal expansion coefficients from their substrates. When the temperature of such a combination is changed, strains are introduced into film. Calculations and strain energies for differently oriented grains in polycrystalline sample were made. The theoretical results checked by x-ray diffractometry, using thick gold copper bonded to glass substrates means thin chromium films. calculations useful investigations line shifts, elastic constants, adhesion,...
Thin films bonded to substrates of different thermal expansion coefficients will experience ``thermal strains'' when their temperature is changed. Calculations these strains and the corresponding strain energies for crystals having various crystallographic orientations relative surface film were made a number fcc bcc metals. Results are given (111), (200), (220), (311), (331), (420), (422), (511), (531), (442), (620), (533) metals Cu, Au, Ag, Al, Ni, Pb, Pd. They basically similar all...
Revision of hip implants due to adverse tissue reactions metal debris has been associated with wear and corrosion the metal-on-metal bearing articulation modular taper interface. Bearing is increased in conditions poor lubrication, which can also lead high friction moments that may cause at This suggests interface should occur simultaneously, was investigated this study.Forty-three large-diameter cobalt-chromium bearings same design, implanted a titanium stem using adapter, were retrieved...
An in situ x-ray investigation of copper films has been carried out. Films were deposited on glass at 80 °K and room temperature high vacuum. Measurements made the as-deposited as well after annealing temperatures up to 200 °C. Values for stacking fault twin densities, particle sizes, strain these have obtained. The presence preferred orientations grain growth during was also studied.
Using low-temperature scanning tunneling microscopy, electron transport across single ${\text{H}}_{2}$- or Co-phthalocyanine molecules was studied. The were adsorbed onto clean Cu(111) surface and Co nanostructures on contacted through a controlled approach of the tip. Soft phonons from molecular side groups promote discrete jump to contact followed by bond formation. Molecular conductances strongly depend substrate but not central atom molecules. This is explained charge transfer...
When thin films adhere to a substrate which has different thermal expansion coefficient, changing the temperature of composite will induce strains in both film and substrate. Calculations strain energy have been made for various polycrystalline diamond cubic, tetragonal, orthorhombic, hexagonal on substrates are assumed be undeformable isotropic elastic properties directions parallel surface Computer programs were developed calculate above quantities cubic semiconductors Ge Si, tetragonal...
A completely newly designed multi-functional facility for the primary calibration of reference solar cells and spectral characterization all cell types has been developed built at PTB. The new is based on successfully applied Differential Spectral Responsivity (DSR) method that allows determination absolute responsivity nonlinearity with lowest uncertainties. By using a tunable laser system, setup avoids main problem monochromator-based systems: low optical power level monochromatic beam....
Abstract Angular‐dependent optical losses can have an effect on the spectral responsivity of photovoltaic devices. When these devices with differing angular‐dependent are exposed to incident direct and diffuse solar irradiance they will perform differently compared perpendicular beam exposure only. However, if angular polarization‐dependent is known, be determined for any given distributed spectrum. Here, we show capabilities a newly developed laser‐based calibration facility traceable...
Water vapor fluxes play a key role in the energy budget of atmosphere, and better flux measurements are needed to improve our understanding formation clouds storms. Large-scale these possible by employing eddy correlation (EC) method from an aircraft. A hygrometer used for such needs deliver temporal resolution at least 10 Hz while reliably operating harsh conditions on exterior Here, we present design concept calibration-free, first-principles, open-path dTDLAS with planar, circular...
Organic light-emitting diodes (OLEDs) are a rapidly developing technology with high innovation potential for displays, lighting, and further applications. Critical issues current research remain the extension of lifetimes and, related to this aim, deeper understanding degradation processes in OLEDs. In present work, we used charge-based deep level transient spectroscopy technique investigate changes charge transport OLEDs induced by electrical aging. Both trap states capturing electrons...
The problem of optimizing the design a fixed matching network located between transmission line and resonant antenna is addressed. contains transformer resonator. Although very simple, it yields dramatic match bandwidth improvement. analysis explicit formulas which provide maximum account for incidental losses in network. results apply to any case where driving point impedance can be approximated by series RLC circuit. Fortunately, such simplification sufficiently accurate useful many...
End of 2013 EURAMET, the European metrology organization opened a call to advance measurement science and technology in field Energy by providing funding for Joint Research Projects (JRP) be funded jointly Commission participating countries frame Metrology Programme (EMRP). This paper describes planned project; no technical results will available at time conference. We feel, however, that CPEM is suitable platform discuss our plans.
The contribution of the Kα1α2 asymmetry to total observed is calculated for x-ray diffraction profiles from fcc specimens containing twin faults. are approximated by exp(−k2x2), (1+k2x2)−2, or (1+k2x2)−1. Calculations, using data filed and annealed Permalloy, show that α1α2 introduces no serious error in determining fault probability as long observations made at values abscissa which correspond least half distance profile maximum zero point. For asymmetries measured closer maximum, can...
Abstract A novel flow switching setup for the dynamic generation and metrological detection of fast, isolated H 2 O concentration changes is presented characterized. Based on this setup, very accurate, static concentrations as well highly step several 1000 ppmv (µmol/mol) can be generated repeated. First experiments show that temporal water vapor gradients up to 10000 ppmv/s measured. a hygrometer characterization method was developed demonstrated using polymer-based device under test (DUT)....
Measuring atmospheric water vapor is an essential but challenging task. The naturally occurring concentrations varies over four orders of magnitude and adsorption desorption processes on sensors in sampling systems can distort attenuate the signal. During airborne measurements H2O concentration gradients that exceed 1400 ppm/s are common pose additional challenge [1]. Despite highly dynamic conditions, especially research aircrafts like HALO, instrument calibration under static conditions...