Electronic Band Structure of Wurtzite GaP Nanowires via Resonance Raman Spectroscopy

Raman measurements are performed on defect-free wurzite GaP nanowires. Resonance Raman measurements are carried out over the excitation energy range between 2.19 and 2.71 eV. Resonances at 2.38 eV and 2.67 eV of the E1(LO) mode and at 2.67 eV of the A1(LO) are observed. The presence of these intensity resonances clearly demonstrates the existence of energy states with Gamma_9hh and Gamma_7V (Gamma_7C) symmetries of the valence (conduction) band and allows to measure WZ phase GaP band energies at the Gamma point. In addition, we have investigated temperature dependent resonant Raman measurements, which allowed us to extrapolate the zero temperature values of Gamma point energies, along with the crystal field and spin-orbit splitting energies. Above results provide a feedback for refining available theoretical calculations to derive the correct wurtzite III-V semiconductor band structure.Comment: 24 pages, 6 figure

Strain induced band alignment in wurtzite-zincblende InAs heterostructured nanowires

We study band alignment in wurtzite-zincblende polytype InAs heterostructured nanowires using temperature dependent resonance Raman measurements. Nanowires having two different wurtzite fractions are investigated. Using visible excitation wavelengths in resonance Raman measurements, we probe the electronic band alignment of these semiconductor nanowires near a high symmetry point of the Brillouin zone (E$_{1}$ gap). The strain in the crystal structure, as revealed from the shift of the phonon mode, explains the observed band alignment at the wurtzite-zincblende interface. Our experimental results are further supported by electronic structure calculations for such periodic heterostructured interface.Comment: 18 pages, 10 figure

Synthesis, Solution, and Structural Characterization of Tetrahydrofuranyl-2,2-Bisphosphonic Acid Disodium Salt

Bisphosphonates are biologically relevant therapeutics for bone disorders and cancer. Reaction of γ-chlorobutyric acid, phosphorus acid, and phosphorus trichloride without the use of solvent gave the tetrahydrofuranyl-2,2-bisphosphonate sodium salt (Na2H2L). The Na2H2L was isolated, characterized in solution by 1H, 13C, and 31P NMR spectroscopy and in solid state by single X-Ray crystallography. The crystal structure showed that the Na2H2L forms in the crystal infinite two-dimensional sheets stacked one parallel to the other. A comparison of the chelating properties of H2L2− with similar hydroxyl bisphosphonate ligands shows that the strength of the Na–O(furanyl/hydroxyl) bond is directly related to the total charge of the ligand anion

Planar Dual-Mode Horn Array with Corporate-Feed Network in Inverted Microstrip Gap Waveguide

The gap waveguide technology was recently introduced as an alternative to hollow waveguides and substrate integrated waveguides for millimeter-wave applications. This paper presents the design of a 4 x 4 planar dual-mode horn array with low loss corporate feed network realized by using an inverted microstrip gap waveguide. The dual-mode horns are compact and designed to reduce the power losses in grating lobes. It is because the diameters of the horn apertures are larger than two wavelengths to allow more space for the feed network and thereby lower conductive losses. The measurements show very good agreement with simulations, with 10% bandwidth of the return loss, 25 dBi realized gain and about 60% aperture efficiency

Design, fabrication and test of integrated micro-scale vibration based electromagnetic generator

This paper discusses the design, fabrication and testing of electromagnetic microgenerators. Three different designs of power generators are partially microfabricated and assembled. Prototype A having a wire-wound copper coil, Prototype B, an electrodeposited copper coil both on a Deep Reactive Ion etched (DRIE) silicon, beam and paddle. Prototype C uses moving NdFeB magnets in between two microfabricated coils. The integrated coil, paddle and beam were fabricated using standard micro-Electro-Mechanical Systems (MEMS) processing techniques. For Prototype A, the maximum measured power output was 148 nW at 8.08 kHz resonant frequency and 3.9 m/s2 acceleration. For prototype B, the microgenerator gave a maximum load power of 23 nW for an acceleration of 9.8 m/s2, at a resonant frequency of 9.83 kHz. This is a substantial improvement in power generated over other microfabricated silicon based generators reported in literature. This generator has a volume of 0.1 cm3 which is lowest of all the silicon based microfabricated electromagnetic power generators reported. To verify the potential of integrated coils in electromagnetic generators, Prototype C was assembled. This generated a maximum load power of 5

Presentation

The articles collected in this volume on “Nominalizations” were selected from papers presented at the JENOM 3 workshop (Troisièmes Journées d’Étude sur les Nominalisations) that we organized at the University of Paris 8 - Saint-Denis, June 17-18, 2010. Articles in this volume address a variety of languages: French, German, Greek, English and Serbo-Croatian. Isabelle Roy and Elena Soare present an introduction to the volume, in which they offer not strictly a state-of-the-art in the study of N..

Nominalizations: new insights and theoretical implications

Introduction Nominalizations (i.e., the formation of nominals from deverbal and deadjectival bases) remain something of a puzzle for linguistic theory, in spite of the central place they have taken in linguistic investigation for about fifty years (starting with the seminal work of Lees 1960 and Chomsky 1970). One of the reasons for this is their obvious trans-categorial status, responsible for their having mixed properties of both nominals and the predicative items (either verbal or adjectiv..

Modeling, Analysis, and Design Insights for Shuttle-based Compact Storage Systems

Shuttle-based compact systems are new automated multi-deep unit-load storage systems with lifts that promise both low operational cost and large volume flexibility. In this paper, we develop novel queuing network models to estimate the performance of both single-tier and multi-tier shuttle-based compact systems. Each tier is modeled as a multi-class semi- open queuing network, whereas the vertical transfer is modeled using an open queue. For a multi-tier system, the models corresponding to tiers and vertical transfer are linked together using the first and second moment information of the queue departure processes. The models can handle both specialized and generic shuttles, and both continuous and discrete lifts. The accuracy of the models is validated through both simulation and a real case. Errors are acceptable for conceptualizing initial designs. Numerical studies provide new design insights. Results show that the best way to minimize expected throughput time in single-tier systems is to have a depth/width ratio around 1.25. Moreover, specialized shuttles are recommended for multi-tier systems because the higher cost of generic shuttles is not balanced by savings in reduced throughput time and equipment need

Extended Full Block S-Procedure for Distributed Control of Interconnected Systems

This paper proposes a novel method for distributed controller synthesis of homogeneous interconnected systems consisting of identical subsystems. The objective of the designed controller is to minimize the L2-gain of the performance channel. The proposed method is an extended formulation of the Full Block S-Procedure (FBSP) where we introduce an additional set of variables. This allows relaxing the block-diagonal structural assumptions on the Lyapunov and multiplier matrices required for distributed control design, which reduces conservatism w.r.t most existing approaches. We show how to decompose the proposed extended FBSP into small synthesis conditions, of the size of one individual subsystem

Do’s and Don’ts in Arctic Research? An interactive Workshop on Community-based Research with Early Career Scientists

Research in Arctic and Sub-Arctic environments presents unique challenges and obstacles, in particular, establishing a necessary baseline understanding of environmental systems in the face of ongoing climate change. Pairing scientific and traditional knowledge approaches can help to close this gap, however creating a bridge between non-local, non-indigenous research scientists and traditional knowledge holders in northern communities can be challenging. For example, most researchers are likely less familiar with local norms, customs, as well as with social systems and protocols, leading to inevitable challenges for the scientists and communities. In a cross-cutting initiative for the International Arctic Science Committee (IASC), Fellows of different the Terrestrial, Cryosphere and Marine Working Groups organized a workshop session on “Community-based Research: Do`s and Don`ts of Arctic Research” during the Young Researchers Workshop at the 11th International Conference on Permafrost in Potsdam, Germany, June 2016. This workshop brought together Early Career Scientists (ECS, including engineers) with resident Arctic representatives and experts to discuss best practices in the exchange of traditional and modern knowledge when conducting research in northern communities. After a short presentation by the panelists, ECSs with invited experts split into small groups with an IASC Fellow as moderator. The break-out groups discussed their experiences and raised questions for the invited experts. These discussions generated a list of “do’s and don’ts” from each group, which were presented and discussed with the larger audiences. The format and organization of the workshop allowed an interactive and fruitful discussion, generating a diverse list of Arctic Research considerations and best practices. Key ideas from the workshop discussions are visualized in the word cloud figure. Recommendations from this workshop included enhancing future support opportunities, like the IASC cross-cutting initiative, to facilitate continued discussions between scientists and northern representatives to maximize the benefits of pairing traditional and modern knowledge to face future challenges