Winged artifacts aim at the imitation of nature’s ingenious method to produce thrust with slim and smart-shaped flapping surfaces—the bending-torsional drive. The kinematics of these surfaces shows, in three dimensions, a bending motion coupled with a simultaneous torsion. This chapter describes the design and development of the artificial bird SmartBird, which was introduced in 2011 on the occasion of the annual international industry fair Hannovermesse. This artwork with articulated wings received worldwide attention through its unprecedented agility. The efficient motion of bodies heavier than air rests on the optimization of target functions like total weight to be balanced by lift, flow resistance to be balanced by thrust, structural layout and reliability, energy storage and, last but not least, smart flight control. From the author’s point of view, the bending-torsional drive just has started its career as a new player in this optimization game.

An oscillating wing exposed to a uniform fluid flow and performing a coupled plunging and pitching motion either produces thrust or extracts energy. The amplitude ratio of the two degrees of freedom determines the respective mode. A stroke-wing engine operates in the mode in which energy is gained. The stroke-wing engine with dual wings enhances the efficiency of the single wing machine. Two wings work in opposite direction and take advantage of the interference effects between the neighbouring wings. Numerical and experimental results are presented for a stroke-wing engine with dual wings. The technology carrier DualWingGenerator operates in air and is intended to compete with wind turbines at selected sites with medium-range wind velocities.

Thin-film-based phase-plates are applied to enhance the contrast of weak-phase objects in transmission electron microscopy. In this work, metal-film-based phase-plates are considered to reduce contamination and electrostatic charging, which up to now limit the application of phase-plates fabricated from amorphous C-films. Their crystalline structure requires a model for the simulation of the effect of crystallinity on the phase-plate properties and the image formation process. The model established in this work is verified by experimental results obtained by the application of a textured nanocrystalline Au-film-based Hilbert phase-plate. Based on the model, it is shown that monocrystalline and textured nanocrystalline phase-plate microstructures of appropriate thickness and crystalline orientation can be a promising approach for phase-contrast transmission electron microscopy.

An artificial bird is introduced which was developed using two new features in biologically-inspired flight, active torsion and partially linear kinematics. Active torsion rests on well established theoretical predictions in unsteady aerodynamics. The concept of partially linear kinematics is inspired by zoological observations on flying locusts. When the wings flap upwards, the servomotor for the active torsion turns the outer wing from a positive angle of incidence within a short fraction of the flapping period into a negative angle of incidence. Between the turning points the angle of torsion remains constant. Numerical calculations confirm the expected benefits compared to passive torsion.

The mutual influence of two profiles is studied in subsonic and transonic 2D viscous flow. The profiles are arranged such that the second one is located downstream of the first one similar to the configuration of a tail plane behind a wing. The physical effect is that of a gust generator. The unsteady wake of the leading profile encounters the trailing profile and effects a load change. A first simplified attempt has been made using a rigid grid where both profiles execute a synchronous heaving motion.

1 Abstract A test stand named ANIPROPRL3is introduced. The device allows the simultaneous recording of dynamic and kinematic quantities like thrust, lift and speed of components for biologically-inspired flight. The models are suspended from a boom and rotate around a hub on a circular path of about 6 m diameter. Thrust is described by an ordinary nonlinear differential equation for the components’ velocity. The repeated solution of a system of nonlinear equations for various values of the velocity over the recorded period of time leads to a prediction of the thrust and all unknown coefficients.

Electron microscopic and electron spectroscopic techniques were applied to study interface properties, microstructure and texture of pyrolytic carbon obtained after short-time chemical vapor deposition (CVD) on planar Si substrates. The pyrolytic carbon was obtained in a hot-wall reactor from methane at a total pressure of 20 kPa and temperature of 1100 °C. Only short depositions between 2.5 and 240 min were performed. The carbon deposition starts with the nucleation of isolated islands. The increase of residence and deposition time leads to the formation of a continuous layer by larger island sizes and higher island densities, a transition from rough to smooth surfaces and formation of pores on smooth surfaces. An increased deposition rate during the first 15 min is observed which is correlated with a granular morphology of the carbon layer. Using BN-covered Si wafers with a surface roughness on a 100 nm scale reduces the texture degree in the vicinity of the interface and strengthens adhesion of the pyrolytic carbon compared to the smooth Si substrate. The texture of high-textured pyrolytic carbon is improved significantly by annealing at 1100 °C.

Pyrolytic carbon layers were deposited from methane/oxygen/argon mixtures on planar substrates (silicon wafers) at a total pressure of 100kPa, a maximum gas residence time of 2s and a temperature of 1100°C. The depositions were performed in a hot-wall reactor with the substrate oriented parallel to the gas flow. Particular attention was paid to factors that influence the reproducibility of the deposited layers. Scanning and transmission electron microscopy were applied to study the thickness profiles and the texture of the carbon layers. The surface topography was investigated by atomic force microscopy. For pyrolytic carbon deposited without oxygen, an alteration from medium- to high-textured carbon is observed with increasing residence time. Islands are observed on the surface of the layer whose size increases with the texture. For pyrolytic carbon deposited with 3% oxygen, lower deposition rates were obtained and a strong modification of the texture is found compared to gas mixtures without oxygen.

Short wavelength (λ<5μm) quantum cascade lasers are of current interest as they operate in the technologically important atmospheric 3–5μm transparency window. For this wavelength range the GaInAs/AlAsSb-on-InP material system offers the advantage of a large conduction band offset of about 1.6eV over the well-established lattice-matched GaInAs/AlInAs-on-InP material combination with a band offset of only 0.5eV. In this paper, we report on molecular beam epitaxial growth and subsequent structural and compositional analysis of GaInAs/AlAsSb quantum wells as well as quantum cascade laser structures. Special emphasis has been laid on establishing a growth procedure which allows the growth of these structures without growth interruption at the GaInAs/AlAsSb interfaces. The epitaxial layer sequences were analyzed by high-resolution X-ray diffraction, secondary ion mass spectrometry, and transmission electron microscopy. Finally, mesa waveguide GaInAs/AlAsSb QC lasers were fabricated emitting around 4.5μm, which could be operated in pulsed mode up to 400K.

The understanding of the correlation between the deposition parameters and the pyrocarbon structure in particular the texture is important to control e.g. the mechanical properties of carbon fiber / carbon matrix composites. The particular aim of the present work was the study of the initial stages of the pyrocarbon deposition. For this purpose, pyrocarbon was grown on silicon wafers in a hot-wall reactor by chemical vapour deposition (CVD). Thickness profiles and the texture of the pyrocarbon were measured as a function of the residence time by scanning and transmission electron microscopy (SEM, TEM). The surface topography was studied by atomic force microscopy (AFM).

A procedure for coupling fluid and structure is described, in which the structure is given by a Finite Element model, and the fluid is computed with a flow solver for compressible flow. The tool is applied to the wing model of a modern transport aircraft, which is equipped with a small contour modification on the upper surface for drag reduction in the shock region. The aeroelastic stability is investigated in comparison to the original contour shape. Particular emphasis is laid on a proper mapping of the flow quantities into the structure and vice versa.

A procedure for coupling fluid and structure is described, in which the structure is given by a Finite Elements model, and the fluid is com- puted with a flow solver for compressible flow. The tool is applied to the wing model of a modern transport aircraft, which is equipped with a small contour modification on the upper surface for drag reduction in the shock region. The aeroelastic stability is investigated in comparison to the original contour shape. Particular emphasis is laid on a proper map- ping of the flow quantities into the structure and vice versa. 1 Introduction In the run-up to even larger transport-aircraft built by the European aircraft industry, several research programs were launched in the past to develop and to assess adaptive features for transport-aircraft wings. Among others, the contour bump in the shock region and the flexible wing are in the focus of attention The bump is expected to reduce the drag in the region of shock/boundary layer interaction, the flexible wing might reduce weight of the control structures. In any of these cases, an investigation was part of the program to which extend the adaptive measures might affect the aeroelastic stability. As an example of the theoretical approach, the paper presents the results for a contour modification (named "bump") on the upper surface of an Airbus A340-like wing model, and describes the method and the numerical tools which have been applied. The wing model considered is related to a former program named AMP (Aeroelastic Model Program) of the French and the German aircraft industry together with the respective research establishments. The AMP wing is the wind tunnel model of a 1:25 scaled Airbus A340 wing.

AbstractOtto Lilienthal, Luftfahrtpionier und Großmeister der Fliegerkunst, hätte seine helle Freude gehabt, wenn er die Schüler und Schülerinnen einer 9. Klasse gesehen hätte, die mit einem künstlichen Vogel in einem Rundlauf die erforderliche Leistung zum Fliegen messen. „Alles Fliegen ist Erzeugen von Luftwiderstand, alle Flugarbeit ist Überwinden von Luftwiderstand”︁ hat er vor mehr als 100 Jahren als Kernsatz geprägt. 20 Jahre lang hatte er Störche beim Flug beobachtet, bevor er 1889 sein bahnbrechendes Werk „Der Vogelflug als Grundlage der Fliegerkunst”︁ veröffentlichte und mit seinen nachfolgenden Gleitflügen der Menschheit eine neue Dimension der Bewegung erschloss. Ungeachtet dieser frühen Erkenntnisse von Lilienthal und anderen herrscht auch heute noch manche Verwirrung hinsichtlich der Frage, warum ein Vogel oder ein Flugzeug fliegt.

We report the linear absorption spectra of relatively large copper iodide nanocrystals embedded in an alumina borosilicate host network structure. The spectra reveal pronounced exciton lines of both the zincblende and the layered hexagonal structures. In the approximation of the weak-confinement regime, the translational masses for the Z(12) and Z(3) excitons, as well as the anisotropy of the Z(12)-exciton band, i.e., the exciton Luttinger parameters, are deduced from the spectral positions of the exciton lines.

Using polarized spatially integrated photoluminescence (PL) and polarized micro-photoluminescence (μ-PL) experiments we have investigated the optical properties of ordered (Al0.5Ga0.5)0.52In0.48P. The anisotropy of the PL cannot be completely understood in terms of the reduced symmetry of the CuPtB-structure. Exciton localization which arises from the inhomogeneous microstructure of ordered crystals is shown to affect the polarization of the PL significantly. Increasing the temperature from 5 to 50–100K leads to a thermally activated occupation of deeply localized states. The polarization of the PL from these states stands in contradiction to the anisotropy which arises from the CuPtB-structure. We demonstrate this by PL measurements of the [001]-emission and by μ-PL measurements on the (110) cleaved edge.