Planar Components Research Articles

Gradient estimation using configurations of two or three spacecraft

Abstract. The forthcoming three-satellite mission Swarm will allow us to investigate plasma processes and phenomena in the upper ionosphere from an in-situ multi-spacecraft perspective. Since with less than four points in space the spatiotemporal ambiguity cannot be resolved fully, analysis tools for estimating spatial gradients, wave vectors, or boundary parameters need to utilise additional information such as geometrical or dynamical constraints. This report deals with gradient estimation where the planar component is constructed using instantaneous three-point observations or, for quasi-static structures, by means of measurements along the orbits of two close spacecraft. A new least squares (LS) gradient estimator for the latter case is compared with existing finite difference (FD) schemes and also with a three-point LS technique. All available techniques are presented in a common framework to facilitate error analyses and consistency checks, and to show how arbitrary combinations of planar gradient estimators and constraints can be formed. The accuracy of LS and FD planar gradient estimators is assessed in terms of prescribed and adjustable discretization parameters to optimise their performance along the satellite orbits. Furthermore, we discuss the implications of imperfect constraint equations for error propagation, and address the effects of sub-scale structures. The two-spacecraft LS scheme is demonstrated using Cluster FGM measurements at a planar and essentially force-free plasma boundary in the solar wind where all three different types of constraints to construct out-of-plane derivatives can be applied.

Stress-function variational method for interfacial stress analysis of adhesively bonded joints

High interfacial stresses at the free edges of adherends are responsible for the debonding failure of adhesively bonded joints (ABJs). In this paper, a general stress-function variational method is formulated to determinate the interfacial shear and normal (peeling) stresses in ABJs in high accuracy. By extending authors’ prior work in stress analysis of bonded joints (Wu and Jenson, 2011), all the planar stress components in the adherends and adhesive layer of an ABJ are expressed in terms of four unknown interfacial stress functions, which are introduced at the upper and lower surfaces of the adhesive layer. A set of governing ordinary differential equations (ODEs) of the four interfacial stress functions is obtained via minimizing the complimentary strain energy of the ABJ, which is further solved by using eigenfunctions. The obtained semi-analytic stress field can satisfy all the traction boundary conditions (BCs) of the ABJ, especially the stress continuity across the bonding lines and the shear-free condition at the ends of adherends and adhesive layer. As an example, the stress field in an adhesively single-sided strap joint is determined by the present method, whose numerical accuracy and reliability are validated by finite element method (FEM) and compared to existing models in the literature. Parameter studies are performed to examine the dependencies of the interfacial stresses of the exemplified ABJ upon the geometries, moduli and temperature change of the adherends and adhesive layer, respectively. The present method is applicable for scaling analysis of joint strength, optimal design of ABJs, etc.

An analytical method for modeling parasitic capacitances of planar components for EMI filters

This paper presents an analytical method for calculating the parasitic capacitances of planar components with 3 dimensions. The calculation is based on the Electric Field Decomposition (EFD) between multi-conductors. 2D formulations used in micro-electronics have been extended to enable the applications on the cases of planar magnetic components. The 3D calculation is then based on an energy approach with the consideration of the magnetic core effects. Prototypes of inductors and coupled inductors allow the validation of this fully analytical approach.

Triply Stacked Heterogeneous Array of Porphyrins and Phthalocyanine through Stepwise Formation of a Fourfold Rotaxane and an Ionic Complex

We report the preparation and crystal structure of a triply stacked metal complex array in which a Cu-phthalocyanine is sandwiched between different Cu-porphyrins. The discrete heterogeneous assembly was prepared through formation of a fourfold rotaxane from a tetradactyl porphyrin with alkylammonium moieties and a phthalocyanine bearing four crown ethers and the subsequent formation of an ionic complex between the fourfold rotaxane and a tetraanionic porphyrin. The tetraanionic porphyrin, Cu-TPPS(4-), is selectively bound to the fourfold rotaxane through cooperative π-π and ionic interactions. The crystal structure revealed the columnar stacked array of the three planar building components in a precise order and spatial arrangement that promote intermolecular electronic communication.

ChemInform Abstract: Ion‐Based Materials Comprising Planar Charged Species

AbstractReview: 126 refs.

Advanced indium tin oxide ceramic sputtering targets (rotary and planar) for transparent conductive nanosized films

Indium tin oxide (ITO) ceramic sputtering targets used for the manufacturing of transparent conductive thin films for electrodes in flat panel displays, solar cells, touch panels, antistatic films and others developed and commercially produced are described. Thanks to optimised compositions and developed technology, commercially producing large size planar and new generation rotary ceramic target components have high density (up to 99·5% of theoretical density), uniform microcrystalline structure and superior properties, e.g. low electrical resistivity. As a result, nanosized thin films produced by direct current magnetron sputtering from the developed targets have uniform nanocrystalline or amorphous structures and superior transmittance (>90%) and low electrical resistivity. The morphology and properties of these films have been studied, depending on the film processing features. The benefits of the developed ITO rotary targets for industrial nanosized film processing (e.g. significant increase in process efficiency, about three times higher target utilisation, practically no nodule formation and particle redeposition during sputtering and reduced processing cost) are outlined.

Productive high-complexity 3D city modeling with point clouds collected from terrestrial LiDAR

To satisfy the needs of photo-realistic and ground-based representation of three-dimensional (3D) city models for a variety of applications, significant efforts have been made to automatically reconstruct detailed 3D building façades from terrestrial LiDAR data. Nonetheless, in real-world applications for high-quality 3D city modeling, three major problems are typically encountered: (1) very low productivity due to fully manual operation, (2) low geometric accuracy of 3D modeling resulting from the process of reducing original LiDAR data, and (3) system failure when importing huge LiDAR data to 3D drawing software. To overcome these limitations, the present study proposes a semi-automatic method entailing a plane component detection based on RANSAC segmentation, boundary tracing of the planar components, and manual drawing of details using the remaining, significantly reduced points. The proposed method was applied to point clouds of various buildings in a high-density area in Korea. In comparison with manual operation, the proposed method was proved to improve modeling productivity in the time-consumption aspect and to facilitate operators’ accurate object drawing. However, for additional automation and completeness of 3D modeling, further study is necessary. The proposed method requires a segmentation algorithm to heuristically determine parameters for the most desirable results as well as to detect curvilinear surfaces in modeling complex and curved façades.

Splitting of the Surface Phonon Modes in Wurtzite Nanowires

We analyze the surface optical modes of GaN nanowires (NW) and perform a comparative study with the characteristics expected for other polar NWs. The theoretical analysis of the modes is performed within the context of the effective medium theory that takes into account the dipolar interaction between neighboring NWs (Maxwell-Garnett approximation). It is shown that deviations of the exciting light from the NWs axis, which coincides with the wurtzite c-axis, result in the anticrossing of two distinct surface phonon branches, leading to their splitting in axial and planar components and the appearance of two peaks in the Raman spectra. Additional calculations are performed that determine the relevant filling factor at which this anticrossing takes place for NWs based on AlN, InN, ZnO, as well as other material systems that may crystallize in the wurtzite structure when grown in the form of NWs, such as GaP and InAs. We analyze the splitting of the surface modes as a function of the material's ionicity.

Flat Optics: Controlling Wavefronts With Optical Antenna Metasurfaces

Conventional optical components rely on the propagation effect to control the phase and polarization of light beams. One can instead exploit abrupt phase and polarization changes associated with scattered light from optical resonators to control light propagation. In this paper, we discuss the optical responses of anisotropic plasmonic antennas and a new class of planar optical components (“metasurfaces”) based on arrays of these antennas. To demonstrate the versatility of metasurfaces, we show the design and experimental realization of a number of flat optical components: 1) metasurfaces with a constant interfacial phase gradient that deflect light into arbitrary directions; 2) metasurfaces with anisotropic optical responses that create light beams of arbitrary polarization over a wide wavelength range; 3) planar lenses and axicons that generate spherical wavefronts and nondiffracting Bessel beams, respectively; and 4) metasurfaces with spiral phase distributions that create optical vortex beams of well-defined orbital angular momentum.

Surface Reconstruction through Point Set Structuring

AbstractWe present a method for reconstructing surfaces from point sets. The main novelty lies in a structure‐preserving approach where the input point set is first consolidated by structuring and resampling the planar components, before reconstructing the surface from both the consolidated components and the unstructured points. The final surface is obtained through solving a graph‐cut problem formulated on the 3D Delaunay triangulation of the structured point set where the tetrahedra are labeled as inside or outside cells. Structuring facilitates the surface reconstruction as the point set is substantially reduced and the points are enriched with structural meaning related to adjacency between primitives. Our approach departs from the common dichotomy between smooth/piecewise‐smooth and primitive‐based representations by gracefully combining canonical parts from detected primitives and free‐form parts of the inferred shape. Our experiments on a variety of inputs illustrate the potential of our approach in terms of robustness, flexibility and efficiency.

Microchannel plate (MCP) functionalized with Ag nanorods as a high-porosity stable SERS-active membrane

Surface-enhanced Raman scattering (SERS) encountered in interstitial gaps between closely positioned metal nanostructures, hot spots, offers tremendous potential for molecular analysis at the trace or single-molecule level. SERS-active sites, hot spots, can be achieved at a higher density when metal nanostructures are configured on a three-dimensional (3D) platform than on a planar two-dimensional (2D) substrate. Yet, 3D platforms demonstrated thus far such as anodized alumina and microstructured fibers offer capillaries/pores either too narrow for the sample to be infused or may not be compatible with microfluidic integration due to their non-planar feature. Here, we introduce a 3D SERS-active platform based on a planar component that is readily available and presents densely packed highly aligned precision microchannels, the so-called microchannel plate (MCP). The microchannels, owing to their alignment biased at a small but precise angle (7°) with respect to the plate surface normal and their reasonably large diameter (~6μm) can be functionalized with Ag nanorods through shadowing-based deposition that requires no other template or lithography. The plate functionalized with Ag nanorods delivers an enhancement factor with values in the range of 106–108 as verified with probing molecules 4-mercatobenzoic acid (4-MBA) and rhodamine-6G.

Ion-based materials comprising planar charged species

Materials comprising planar units have the propensity to form stacking assemblies with nanoscale architectures and intriguing properties. In this feature article, some recent examples of ion-based materials comprising positively and negatively charged planar species are described. Various ion-based solid and soft materials can be formed by planar charged species alone or with the aid of other components. It is more challenging to prepare planar anions than planar cations; however, the noncovalent association of electronically neutral planar anion receptors and anions is an efficient strategy for the preparation of planar anions. Suitable candidates include dipyrrolyldiketone boron complexes, which exhibit the formation of various receptor-anion complexes and can be used to fabricate advanced materials in combination with countercations. Ion-based materials consisting of planar charged components have potential as electrically conductive materials, resulting from the ordered arrangement of the planar charged species.

Torsional Influences within Disordered Organic Electronic Materials Based upon Non-Benzenoid 1,6-Methano[10]annulene Rings

Conjugated polymers and small molecules containing the nonplanar aromatic 1,6-methano[10]annulene were synthesized in an effort to understand how torsional differences between planar and nonplanar π-electron components influence the electronic properties of π-conjugated materials. The polymers and small molecule model systems contain commonly employed aromatic subunits such as thiophene, diketopyrrolopyrrole, and 2,1,3-benzothiadiazole, leading to electron donor and donor–acceptor polymers. The curved geometry of 1,6-methano[10]annulene can lead to reduced local torsional strain in semiconducting polymers relative to large planar aromatics, potentially increasing intrapolymer conjugation. The relative amount of effective conjugation length increase granted by the annulene in each system of regioisomers was interrogated through the use of UV–vis and photoluminescence spectroscopy and electrochemistry, and it was found that 1,6-methano[10]annulene relieves some torsional strain associated with solubilizing alkyl chains clashing with aromatic rings along the polymer backbone. The polymers were also found to be highly disordered in thin films yet still provided reasonable hole mobilities (ca. 10–4 cm2/(V s)) in OFET devices. These results suggest that methano[10]annulene or other curved aromatics may prove useful in the future development of organic electronics.

MPIE/MoM Acceleration With a General-Purpose Graphics Processing Unit

In this paper, we describe an accelerated implementation of the Method of Moments (MoM). A framework is proposed, exploiting the graphics processing unit (GPU) computing power by means of the software platform compute unified device architecture (CUDA). The mixed-potential integral-equation formulation, applied to microstrip circuit modeling, is adopted, and both the impedance matrix computation and the linear system solution of the MoM are accelerated. The latter point has been handled by considering both a direct dense (LU-based) and an iterative sparse (bi-conjugate gradient stabilized) solver. The best suited method is selected automatically during a thresholding phase, which renders the impedance matrix as sparse as possible. The effectiveness of the GPU-enabled MoM has been extensively tested in the analysis of planar circuits and components. The results achieved confirm the validity, accuracy, and high performance of the proposed approach.

On the role of vortex stretching in energy optimal growth of three-dimensional perturbations on plane parallel shear flows

AbstractThe three-dimensional linearized optimal energy growth mechanism, in plane parallel shear flows, is re-examined in terms of the role of vortex stretching and the interplay between the spanwise vorticity and the planar divergent components. For high Reynolds numbers the structure of the optimal perturbations in Couette, Poiseuille and mixing-layer shear profiles is robust and resembles localized plane waves in regions where the background shear is large. The waves are tilted with the shear when the spanwise vorticity and the planar divergence fields are in (out of) phase when the background shear is positive (negative). A minimal model is derived to explain how this configuration enables simultaneous growth of the two fields, and how this mutual amplification affects the optimal energy growth. This perspective provides an understanding of the three-dimensional growth solely from the two-dimensional dynamics on the shear plane.

Optically Transparent and Flexible Graphene Reciprocal and Nonreciprocal Microwave Planar Components

The sheet resistance of graphene has been recently reduced below the level of previous optically transparent conductive materials, making graphene, with its additional advantage of mechanical flexibility, the best candidate for future transparent electronics. We investigate here the viability of microwave planar components using graphene sheets as conductors towards optically transparent and flexible radio systems. Specifically, we study the waveguiding and nonreciprocal properties of such components, through the arbitrary example of a coplanar waveguide (CPW) structure, using the 2-D finite difference frequency domain (FDFD) technique. It is shown that reciprocal graphene-based components of acceptably low loss levels are achievable using graphene sheets of the lowest available resistivity, while nonreciprocal components with graphene conductors still exhibit prohibitive loss due to a fundamental trade-off between nonreciprocity and carrier density in graphene.

Three-Dimensional Spin Rotations at the Fermi Surface of a Strongly Spin-Orbit Coupled Surface System

The spin texture of the metallic two-dimensional electron system (sqrt[3]×sqrt[3])-Au/Ge(111) is revealed by fully three-dimensional spin-resolved photoemission, as well as by density functional calculations. The large hexagonal Fermi surface, generated by the Au atoms, shows a significant splitting due to spin-orbit interactions. The planar components of the spin exhibit a helical character, accompanied by a strong out-of-plane spin component with alternating signs along the six Fermi surface sections. Moreover, in-plane spin rotations toward a radial direction are observed close to the hexagon corners. Such a threefold-symmetric spin pattern is not described by the conventional Rashba model. Instead, it reveals an interplay with Dresselhaus-like spin-orbit effects as a result of the crystalline anisotropies.

Magneto-optical visualization of three spatial components of inhomogeneous stray fields

The article deals with the physical principles of magneto-optical visualization (MO) of three spatial components of inhomogeneous stray fields with the help of FeCo metal indicator films in the longitudinal Kerr effect geometry. The inhomogeneous field is created by permanent magnets. Both p- and s-polarization light is used for obtaining MO images with their subsequent summing, subtracting and digitizing. As a result, the MO images and corresponding intensity coordinate dependences reflecting the distributions of the horizontal and vertical magnetization components in pure form have been obtained. Modeling of both the magnetization distribution in the indicator film and the corresponding MO images shows that corresponding to polar sensitivity the intensity is proportional to the normal field component, which permits normal field component mapping. Corresponding to longitudinal sensitivity, the intensity of the MO images reflects the angular distribution of the planar field component. MO images have singular points in which the planar component is zero and their movement under an externally homogeneous planar field permits obtaining of additional information on the two planar components of the field under study. The intensity distribution character in the vicinity of sources and sinks (singular points) remains the same under different orientations of the light incidence plane. The change of incident plane orientation by π/2 alters the distribution pattern in the vicinity of the saddle points.

Josephson Hall current in a noncentrosymmetric superconductor/ferromagnet/superconductor junction

We theoretically study the transverse spin and charge transport in a 2D noncentrosymmetric superconductor (NCS)/ferromagnet (FM)/superconductor Josephson junction, in which the NCS has a dominant triplet order parameter and helical edge states. It is predicted that both equilibrium spin and charge Hall currents can flow transversely in the junction and are driven by the superconducting phase gradient. The physical origin of the Josephson Hall current is the broken time-reversal symmetry due to the FM and the mixing of the helical edge states. The Hall currents are sensitive to the FM magnetization direction, and the planar magnetization component is vitally important because it can lead to a spin flip effect that makes the Cooper pairs tunnel between unequal chiral edge states of the two NCSs.

Hybrid Heterojunction Solar Cell Based on Organic–Inorganic Silicon Nanowire Array Architecture

Silicon nanowire arrays (SiNWs) on a planar silicon wafer can be fabricated by a simple metal-assisted wet chemical etching method. They can offer an excellent light harvesting capability through light scattering and trapping. In this work, we demonstrated that the organic-inorganic solar cell based on hybrid composites of conjugated molecules and SiNWs on a planar substrate yielded an excellent power conversion efficiency (PCE) of 9.70%. The high efficiency was ascribed to two aspects: one was the improvement of the light absorption by SiNWs structure on the planar components; the other was the enhancement of charge extraction efficiency, resulting from the novel top contact by forming a thin organic layer shell around the individual silicon nanowire. On the contrary, the sole planar junction solar cell only exhibited a PCE of 6.01%, due to the lower light trapping capability and the less hole extraction efficiency. It indicated that both the SiNWs structure and the thin organic layer top contact were critical to achieve a high performance organic/silicon solar cell.