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Suspended Si/air high contrast subwavelength gratings for long-wavelength infrared reflectors

Proceedings of SPIE - The International Society for Optical engineering 2013年 8633卷

作者： Foley, Justin M. Phillips, Jamie D. Applied Physics Program University of Michigan 450 Church St. Ann Arbor MI 48109-1040 United States Electrical Engineering and Computer Science Department University of Michigan 1301 Beal Ave. Ann Arbor MI 48109-2122 United States

ISBN: (纸本)9780819494023

We report broadband reflectance in the long-wavelength infrared (LWIR, 8-12 μm) utilizing suspended-Si, high-index-contrast subwavelength gratings (HCGs). Iterative design optimization using finite element analysis software has been performed accounting for silicon's wavelength-dependent index of refraction and extinction coefficient. Grating arrays were fabricated using commercial silicon-on-insulator (SOI) substrates, photolithography and reactive ion etching; subsequent selective wet etching of SiO2was used to provide suspended Si/air gratings. Fourier transform infrared (FTIR) spectroscopy demonstrates broadband, polarization-dependent reflectance between 8.5 and 12 μm, which agrees with the simulated response. © 2013 SPIE.

关键词： Infrared radiation Diffraction gratings Finite element method Fourier transform infrared spectroscopy Hyperspectral imaging Infrared devices Reactive ion etching Reflection Refractive index Silica Silicon on insulator technology Silicon oxides Broadband reflector Filter HCG reflector High contrast gratings Long wavelength infrared LWIR

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Ultrahigh throughput plasma processing of free standing silicon nanocrystals with lognormal size distribution

Ultrahigh throughput plasma processing of free standing sili...

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作者： Doǧan, Ilker Kramer, Nicolaas J. Westermann, René H. J. Dohnalová, Kateřina Smets, Arno H. M. Verheijen, Marcel A. Gregorkiewicz, Tom Van De Sanden, Mauritius C. M. Department of Applied Physics Eindhoven University of Technology P.O. Box 513 5600 MB Eindhoven Netherlands Van der Waals-Zeeman Institute University of Amsterdam Science Park 904 1098 XH Amsterdam Netherlands Photovoltaic Materials and Devices Laboratory Delft University of Technology P.O. Box 5031 2600 GA Delft Netherlands P.O. Box 1207 3430 BE Nieuwegein Netherlands Department of Mechanical Engineering University of Minnesota Minneapolis MN 55455 United States

We demonstrate a method for synthesizing free standing silicon nanocrystals in an argon/silane gas mixture by using a remote expanding thermal plasma. Transmission electron microscopy and Raman spectroscopy measurements reveal that the distribution has a bimodal shape consisting of two distinct groups of small and large silicon nanocrystals with sizes in the range 2-10 nm and 50-120 nm, respectively. We also observe that both size distributions are lognormal which is linked with the growth time and transport of nanocrystals in the plasma. Average size control is achieved by tuning the silane flow injected into the vessel. Analyses on morphological features show that nanocrystals are monocrystalline and spherically shaped. These results imply that formation of silicon nanocrystals is based on nucleation, i.e., these large nanocrystals are not the result of coalescence of small nanocrystals. Photoluminescence measurements show that silicon nanocrystals exhibit a broad emission in the visible region peaked at 725 nm. Nanocrystals are produced with ultrahigh throughput of about 100 mg/min and have state of the art properties, such as controlled size distribution, easy handling, and room temperature visible photoluminescence. © 2013 American Institute of physics.

关键词： Nanocrystals

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Efficiency and effectiveness analysis of a new direct drive miniature quadruped robot

Efficiency and effectiveness analysis of a new direct drive ...

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IEEE International Conference on Robotics and Automation (ICRA)

作者： Christopher Y. Brown Dana E. Vogtmann Sarah Bergbreiter Johns Hopkins University Applied Physics Laboratory Laurel MD US University of Maryland College Park MD USA Department of Mechanical Engineering the Institute for Systems Research and the Maryland Robotics Center University of Maryland College Park MD USA

ISBN: (纸本)9781467356404

This paper introduces a new, 50g miniature robot (Figure 1 and attached video) that uses four direct-drive hybrid wheel/legs and has been clocked at speeds exceeding 30 body lengths/s. The lowest recorded cost of transport (defined as total energy to move the robot mass a given distance) is 0.90. We discuss hardware considerations for design of robots at this scale, and the benefits of a direct-drive system over coupled transmissions. We develop a simple simulation model to examine the effects of drive speed and mechanical properties of the legs, and compare the results with experimental data on efficiency and effectiveness of locomotion with various leg designs.

关键词： Legged locomotion Brushless DC motors Friction Foot

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High-pressure synthesis of the BaIrO3 perovskite: A Pauli paramagnetic metal with a Fermi liquid ground state

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Physical Review B 2013年第20期88卷 205114-205114页

作者： J.-G. Cheng T. Ishii H. Kojitani K. Matsubayashi A. Matsuo X. Li Y. Shirako J.-S. Zhou J. B. Goodenough C. Q. Jin M. Akaogi Y. Uwatoko Institute for Solid State Physics University of Tokyo 5-1-5 Kashiwanoha Kashiwa Chiba 277-8581 Japan Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences Beijing 100190 China Department of Chemistry Gakushuin University 1-5-1 Mejiro Toshima-ku Tokyo 171-8588 Japan Materials Science and Engineering Program/Mechanical Engineering University of Texas at Austin Texas 78712 USA

BaIrO3 adopts the 9R polytype structure if it is synthesized at ambient pressure. High-pressure and high-temperature treatments up to 10 GPa have led to other 5H and 6H polytype phases, which are quenchable to the ambient condition. However, the single-phase 3C perovskite, the end member of polytypes, has not been obtained so far. Here we report the high-pressure synthesis of BaIrO3 perovskite under 25 GPa and 1150 °C. Rietveld refinement on the powder x-ray diffraction pattern revealed that this new compound crystallizes in a tetragonal I4/mcm structure rather than the expected cubic Pm-3m structure. The new perovskite is a Pauli paramagnetic metal with a Fermi liquid ground state, i.e., ρ ∝ T2 below 6 K. The availability of BaIrO3 perovskite also allows completion of the structure-physical property evolution in the AIrO3 perovskites (A = Ca, Sr, Ba). The Fermi energy located in bands originated from Ir: 5d and O: 2p electrons are found to be very sensitive to the change of crystal structure.

关键词： PEROVSKITE synthesis FERMI liquids GROUND state (Quantum mechanics) X-ray diffraction FERMI energy

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Human genome meeting 2016 : Houston, TX, USA. 28 February - 2 March 2016

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Human genomics 2016年第1期10 Suppl 1卷 12页

作者： A. K. Srivastava Y. Wang R. Huang C. Skinner T. Thompson L. Pollard T. Wood F. Luo R. Stevenson R. Polimanti J. Gelernter X. Lin I. Y. Lim Y. Wu A. L. Teh L. Chen I. M. Aris S. E. Soh M. T. Tint J. L. MacIsaac F. Yap K. Kwek S. M. Saw M. S. Kobor M. J. Meaney K. M. Godfrey Y. S. Chong J. D. Holbrook Y. S. Lee P. D. Gluckman N. Karnani A. Kapoor D. Lee A. Chakravarti C. Maercker F. Graf M. Boutros G. Stamoulis F. Santoni P. Makrythanasis A. Letourneau M. Guipponi N. Panousis M. Garieri P. Ribaux E. Falconnet C. Borel S. E. Antonarakis S. Kumar J. Curran J. Blangero S. Chatterjee J. Akiyama D. Auer C. Berrios L. Pennacchio T. R. Donti G. Cappuccio M. Miller P. Atwal A. Kennedy A. Cardon C. Bacino L. Emrick J. Hertecant F. Baumer B. Porter M. Bainbridge P. Bonnen B. Graham R. Sutton Q. Sun S. Elsea Z. Hu P. Wang Y. Zhu J. Zhao M. Xiong David A. Bennett A. Hidalgo-Miranda S. Romero-Cordoba S. Rodriguez-Cuevas R. Rebollar-Vega E. Tagliabue M. Iorio E. D’Ippolito S. Baroni B. Kaczkowski Y. Tanaka H. Kawaji A. Sandelin R. Andersson M. Itoh T. Lassmann Y. Hayashizaki P. Carninci A. R. R. Forrest C. A. Semple E. A. Rosenthal B. Shirts L. Amendola C. Gallego M. Horike-Pyne A. Burt P. Robertson P. Beyers C. Nefcy D. Veenstra F. Hisama R. Bennett M. Dorschner D. Nickerson J. Smith K. Patterson D. Crosslin R. Nassir N. Zubair T. Harrison U. Peters G. Jarvik F. Menghi K. Inaki X. Woo P. Kumar K. Grzeda A. Malhotra H. Kim D. Ucar P. Shreckengast K. Karuturi J. Keck J. Chuang E. T. Liu B. Ji A. Tyler G. Ananda G. Carter H. Nikbakht M. Montagne M. Zeinieh A. Harutyunyan M. Mcconechy N. Jabado P. Lavigne J. Majewski J. B. Goldstein M. Overman G. Varadhachary R. Shroff R. Wolff M. Javle A. Futreal D. Fogelman L. Bravo W. Fajardo H. Gomez C. Castaneda C. Rolfo J. A. Pinto K. C. Akdemir L. Chin S. Patterson C. Statz S. Mockus S. N. Nikolaev X. I. Bonilla L. Parmentier B. King F. Bezrukov G. Kaya V. Zoete V. Seplyarskiy H. Sharpe T. McKee K. Popadin N. Basset-Seguin R. Ben Chaabene M. Andrianova C. Verdan K. Grosdemange O. Sumara M. E JCSRI Greenwood Genetic Center Greenwood USA School of Computing Clemson University Clemson USA Biochemical Genetics Laboratory Greenwood Genetic Center Greenwood USA Department Psychiatry Yale Sch Med and VA CT Healthcare Center West Haven USA Department Genetics Yale Sch Med and VA CT Healthcare Center West Haven USA Department Neurobiology Yale Sch Med and VA CT Healthcare Center West Haven USA Singapore Institute for Clinical Sciences Singapore Singapore National University of Singapore Singapore Singapore University of British Columbia Vancouver Canada KK Women’s and Children’s Hospital Singapore Singapore University of Southampton and University Hospital Southampton NHS Foundation Trust Southampton UK University of Auckland Auckland New Zealand McKusick-Nathans Institute of Genetic Medicine Johns Hopkins University School of Medicine Baltimore USA Esslingen University of Applied Sciences Esslingen Germany German Cancer Research Center Heidelberg Germany Department of Genetic Medicine and Development University of Geneva Medical School Geneva Switzerland Geneva University Hospitals-HUG Service of Genetic Medicine Geneva Switzerland GE3 Institute of Genetics and Genomics of Geneva University of Geneva Medical School Geneva Switzerland South Texas Diabetes and Obesity Institute School of Medicine University of Texas Rio-Grande Valley Edinburg USA South Texas Diabetes and Obesity Institute School of Medicine University of Texas Rio-Grande Valley Brownsville USA Institute of Genetic Medicine Johns Hopkins University Baltimore USA Genomics Division Lawrence Berkeley National Laboratory Berkeley USA Molecular and Human Genetics Baylor College of Medicine Houston USA Department of Translational Medical Sciences Federico II University Naples Italy Metabolon Inc Durham USA Section of Pediatric Neurology and Neuroscience Baylor College of Medicine Houston USA Tawam Hospital Abu Dhabi United Arab Emirates Stanford Medical School Stanford USA Sch

O1 The metabolomics approach to autism: identification of biomarkers for early detection of autism spectrum disorder A. K. Srivastava, Y. Wang, R. Huang, C. Skinner, T. Thompson, L. Pollard, T. Wood, F. Luo, R. Stevenson O2 Phenome-wide association study for smoking- and drinking-associated genes in 26,394 American women with African, Asian, European, and Hispanic descents R. Polimanti, J. Gelernter O3 Effects of prenatal environment, genotype and DNA methylation on birth weight and subsequent postnatal outcomes: findings from GUSTO, an Asian birth cohort X. Lin, I. Y. Lim, Y. Wu, A. L. Teh, L. Chen, I. M. Aris, S. E. Soh, M. T. Tint, J. L. MacIsaac, F. Yap, K. Kwek, S. M. Saw, M. S. Kobor, M. J. Meaney, K. M. Godfrey, Y. S. Chong, J. D. Holbrook, Y. S. Lee, P. D. Gluckman, N. Karnani, GUSTO study group O4 High-throughput identification of specific qt interval modulating enhancers at the SCN5A locus A. Kapoor, D. Lee, A. Chakravarti O5 Identification of extracellular matrix components inducing cancer cell migration in the supernatant of cultivated mesenchymal stem cells C. Maercker, F. Graf, M. Boutros O6 Single cell allele specific expression (ASE) IN T21 and common trisomies: a novel approach to understand DOWN syndrome and other aneuploidies G. Stamoulis, F. Santoni, P. Makrythanasis, A. Letourneau, M. Guipponi, N. Panousis, M. Garieri, P. Ribaux, E. Falconnet, C. Borel, S. E. Antonarakis O7 Role of microRNA in LCL to IPSC reprogramming S. Kumar, J. Curran, J. Blangero O8 Multiple enhancer variants disrupt gene regulatory network in Hirschsprung disease S. Chatterjee, A. Kapoor, J. Akiyama, D. Auer, C. Berrios, L. Pennacchio, A. Chakravarti O9 Metabolomic profiling for the diagnosis of neurometabolic disorders T. R. Donti, G. Cappuccio, M. Miller, P. Atwal, A. Kennedy, A. Cardon, C. Bacino, L. Emrick, J. Hertecant, F. Baumer, B. Porter, M. Bainbridge, P. Bonnen, B. Graham, R. Sutton, Q. Sun, S. Elsea O10 A novel causal methylation network approach to Alzheimer’s

关键词： Pulmonary Arterial Hypertension Oral Squamous Cell Carcinoma Deep Neural Network Autosomal Recessive Polycystic Kidney Disease Whole Genome Bisulfite Sequencing

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Manipulating Ferroelectric Domains in Nanostructures Under Electron Beams

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Physical Review Letters 2013年第16期111卷 165702-165702页

作者： R. Ahluwalia N. Ng A. Schilling R. G. P. McQuaid D. M. Evans J. M. Gregg D. J. Srolovitz J. F. Scott Institute of High Performance Computing Singapore 138632 Singapore School of Mathematics and Physics Queen’s University Belfast Belfast BT7 1NN United Kingdom Departments of Materials Science and Engineering Mechanical Engineering and Applied Mechanics University of Pennsylvania Philadelphia Pennsylvania 19104 USA Department of Physics Cavendish Laboratory J. J. Thompson Avenue Cambridge CB3 0HE United Kingdom

Freestanding BaTiO3 nanodots exhibit domain structures characterized by distinct quadrants of ferroelastic 90° domains in transmission electron microscopy (TEM) observations. These differ significantly from flux-closure domain patterns in the same systems imaged by piezoresponse force microscopy. Based upon a series of phase field simulations of BaTiO3 nanodots, we suggest that the TEM patterns result from a radial electric field arising from electron beam charging of the nanodot. For sufficiently large charging, this converts flux-closure domain patterns to quadrant patterns with radial net polarizations. Not only does this explain the puzzling patterns that have been observed in TEM studies of ferroelectric nanodots, but also suggests how to manipulate ferroelectric domain patterns via electron beams.

关键词： FERROELECTRIC domains FERROELECTRIC materials DOMAIN structure PARTICLES (Nuclear physics) ELECTRON beams PARTICLE beams

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Simulation and Test for the Thermal Behaviour of a Prototype Synchronous Generator with HTS Armature Windings

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physics Procedia 2013年 45卷 257-260页

作者： X.-Y. Yu T.-M. Qu P. Song L.-N. Li D.-X. Chen Z. Han Key Laboratory for Advanced Materials Processing Technology Department of Mechanical Engineering Tsinghua University Beijing 100084 China Applied Superconductivity Research Centre Department of Physics Tsinghua University Beijing 100084 China ICREA and Grup d’Electromagnetisme Departament de Fisica Universitat Autonoma de Barcelona 08193 Bellaterra Barcelona Spain

A synchronous generator prototype with HTS armature windings and a permanent magnet rotor (HTS-PM) was developed. The temperature evolution during cooling and operation processes of the HTS coils was analyzed by finite element method (FEM). The simulated results coincided well with the temperature measurement data acquired by PT-100 sensors. Cooling time, terminal temperature, contact thermal conductivity, during cooling, as well as the proportion between real and calculated iron loss, contact thermal conductivity, at various rotating speeds during operation, were worked out using the FEM model.

关键词： Synchronous generator HTS armature windings Temperature evolution Finite element method PT-100 sensors

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Light‐Directing Omnidirectional Circularly Polarized Reflection from Liquid‐Crystal Droplets†

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Angewandte Chemie 2014年第7期127卷

作者： Jing Fan Yannian Li Hari Krishna Bisoyi Rafael S. Zola Deng‐ke Yang Timothy J. Bunning David A. Weitz Quan Li School of Engineering and Applied Sciences Harvard University Cambridge MA 02138 (USA) Liquid Crystal Institute and Chemical Physics Interdisciplinary Program Kent State University Kent OH 44242 (USA) Departamento de Física Universidade Tecnológica Federal do Paraná‐Apucarana PR 86812‐460 (Brazil) Materials and Manufacturing Directorate Air Force Research Laboratory WPAFB Dayton OH 45433 (USA) Department of Physics Harvard University Cambridge MA 02138 (USA)

Constructing and tuning self‐organized three‐dimensional (3D) superstructures with tailored functionality is crucial in the nanofabrication of smart molecular devices. Herein we fabricate a self‐organized, phototunable 3D photonic superstructure from monodisperse droplets of one‐dimensional cholesteric liquid crystal (CLC) containing a photosensitive chiral molecular switch with high helical twisting power. The droplets are obtained by a glass capillary microfluidic technique by dispersing into PVA solution that facilitates planar anchoring of the liquid‐crystal molecules at the droplet surface, as confirmed by the observation of normal incidence selective circular polarized reflection in all directions from the core of individual droplet. Photoirradiation of the droplets furnishes dynamic reflection colors without thermal relaxation, whose wavelength can be tuned reversibly by variation of the irradiation time. The results provided clear evidence on the phototunable reflection in all directions.

关键词： Farbe Flüssigkristalltröpfchen Mikrofluidik Photonische Kristalle Selektive Reflexion

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Using the Population‐Shift Mechanism to Rationally Introduce “Hill‐type” Cooperativity into a Normally Non‐Cooperative Receptor†

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Angewandte Chemie 2014年第36期126卷

作者： Anna J. Simon Alexis Vallée‐Bélisle Francesco Ricci Herschel M. Watkins Kevin W. Plaxco Biomolecular Science and Engineering Program UC Santa Barbara Santa Barbara CA 93106 (USA) Département de Chimie Université de Montréal QC (Canada) Dipartimento di Scienze e Tecnologie Chimiche University of Rome Tor Vergata Via della Ricerca Scientifica (Italy) Current address: Department of Applied Physics Stanford University (USA) Department of Chemistry and Biochemistry UC Santa Barbara (USA)

Allosteric cooperativity, which nature uses to improve the sensitivity with which biomolecular receptors respond to small changes in ligand concentration, could likewise be of use in improving the responsiveness of artificial biosystems. Thus motivated, we demonstrate here the rational design of cooperative molecular beacons, a widely employed DNA sensor, using a generalizable population‐shift approach in which we engineer receptors that equilibrate between a low‐affinity state and a high‐affinity state exposing two binding sites. Doing so we achieve cooperativity within error of ideal behavior, greatly steepening the beacon’s binding curve relative to that of the parent receptor. The ability to rationally engineer cooperativity should prove useful in applications such as biosensors, synthetic biology and “smart” biomaterials, in which improved responsiveness is of value.

关键词： Allosterie DNA Kooperative Effekte Sensoren Synthesebiologie

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Preconditioners and Electron Density Optimization in Orbital-Free Density Functional Theory

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Communications in Computational physics 2012年第6期12卷 135-161页

作者： Linda Hung Chen Huang Emily A.Carter Program in Applied and ComputationalMathematics Princeton UniversityPrincetonNJ 08544USA Department of Physics Princeton UniversityPrincetonNJ 08544USA Department of Mechanical and Aerospace Engineering and Andlinger Center for Energy and the Environment Princeton UniversityPrincetonNJ 08544USA

Orbital-free density functional theory(OFDFT)is a quantum mechanical method in which the energy of a material depends only on the electron density and ionic *** examine some popular algorithms for optimizing the electron density distribution in OFDFT,explaining their suitability,benchmarking their performance,and suggesting some *** start by describing the constrained optimization problem that encompasses electron density ***,we discuss the line search(including Wolfe conditions)and the nonlinear conjugate gradient and truncated Newton algorithms,as implemented in our open source OFDFT *** finally focus on preconditioners derived from OFDFT energy *** preconditioners are successful for simulation cells of all sizes without regions of low electron-density and for small simulation cells with such regions.

关键词： Density functional theory truncated Newton method conjugate gradient method constrained optimization benchmarks

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