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https://www.readbyqxmd.com/read/28106748/two-dimensional-numerical-simulations-of-ultrasound-in-liquids-with-gas-bubble-agglomerates-examples-of-bubbly-liquid-type-acoustic-metamaterials-blamms
#1
Christian Vanhille
This work deals with a theoretical analysis about the possibility of using linear and nonlinear acoustic properties to modify ultrasound by adding gas bubbles of determined sizes in a liquid. We use a two-dimensional numerical model to evaluate the effect that one and several monodisperse bubble populations confined in restricted areas of a liquid have on ultrasound by calculating their nonlinear interaction. The filtering of an input ultrasonic pulse performed by a net of bubbly-liquid cells is analyzed. The generation of a low-frequency component from a single cell impinged by a two-frequency harmonic wave is also studied...
January 17, 2017: Sensors
https://www.readbyqxmd.com/read/28106426/unified-time-and-frequency-picture-of-ultrafast-atomic-excitation-in-strong-laser-fields
#2
H Zimmermann, S Patchkovskii, M Ivanov, U Eichmann
Excitation and ionization in strong laser fields lies at the heart of such diverse research directions as high-harmonic generation and spectroscopy, laser-induced diffraction imaging, emission of femtosecond electron bunches from nanotips, self-guiding, filamentation and mirrorless lasing during propagation of light in atmospheres. While extensive quantum mechanical and semiclassical calculations on strong-field ionization are well backed by sophisticated experiments, the existing scattered theoretical work aiming at a full quantitative understanding of strong-field excitation lacks experimental confirmation...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28098287/second-harmonic-phase-determination-by-real-time-in-situ-interferometry
#3
Bason Clancy, Joshua Salafsky
Second Harmonic Generation (SHG) has emerged as a highly sensitive probe of protein conformation. SHG can also be used to determine the tilt angle of an SHG-active moiety bound to a surface-adsorbed protein through polarization-dependent measurements. However, due to the coherent nature of SHG, interference occurs between the SHG produced by the SHG-active moieties and background sources at a solid-liquid interface, obscuring the signal of interest. In order to separate the protein-specific signal from the background signal, the phase difference between these two different sources of SHG must be determined...
January 18, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28098285/kb-po4-f-a-novel-acentric-deep-ultraviolet-material
#4
Ji-Hong Jiang, Lin-Chuan Zhang, Ya-Xi Huang, Zhi-Mei Sun, Yuanming Pan, Jin-Xiao Mi
Two challenges to grow KBe2BO3F2 (KBBF), the best known deep-ultraviolet nonlinear optical (NLO) material to date, are the limited crystal sizes and the use of a highly toxic element (Be). Herein we report on the discovery of a novel anhydrous non-centrosymmetric alkali fluorinated borophosphate KB(PO4)F (KBPF) featuring a cut-off wavelength of less than 200 nm and a large second-harmonic generation (SHG) effect similar to KH2PO4 (KDP), hence representing a new promising deep-ultraviolet NLO material. The KBPF crystals consisting of common elements can be grown using green and cost effective processes and do not show any detectable hygroscopicity...
January 18, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/28094990/bridging-the-gap-between-dielectric-nanophotonics-and-the-visible-regime-with-effectively-lossless-gap-antennas
#5
Javier Cambiasso, Gustavo Grinblat, Yi Li, Aliaksandra Rakovich, Emiliano Cortés, Stefan A Maier
We present all-dielectric gallium phosphide (GaP) nanoantennas as an efficient nanophotonic platform for surface-enhanced second harmonic generation (SHG) and fluorescence (SEF), showing negligible losses in the visible range. Employing single GaP nanodisks, we observe an increase of more than three orders of magnitude in the SHG signal in comparison with the bulk. This constitutes an SHG efficiency as large as 0.0002%, which is, to the best of our knowledge, the highest yet achieved value produced by a single nano-object in the optical region...
January 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28094977/crystallographic-mapping-of-guided-nanowires-by-second-harmonic-generation-polarimetry
#6
Lior Neeman, Regev Ben-Zvi, Katya Rechav, Ronit Popovitz-Biro, Dan Oron, Ernesto Joselevich
The growth of horizontal nanowires (NWs) guided by epitaxial and graphoepitaxial relations with the substrate is becoming increasingly attractive owing to the posibility of controlling their position, direction and crystallographic orientation. In guided NWs, as opposed to the extensively characterized vertically grown NWs, there is an increasing need for understanding the relation between structure and properties, specifically the role of the epitaxial relation with the substrate. Furthermore, the uniformity of crystallographic orientation along guided NWs and over the substrate has yet to be checked...
January 17, 2017: Nano Letters
https://www.readbyqxmd.com/read/28092628/ultrafast-adiabatic-second-harmonic-generation
#7
Asaf Dahan, Assaf Levanon, Mordechai Katz, Haim Suchowski
We introduce a generalization of the adiabatic frequency conversion method for an efficient conversion of ultrashort pulses in the full nonlinear regime. Our analysis takes into account dispersion as well as two-photon processes and Kerr effect, allowing complete analysis of any three waves with arbitrary phase mismatched design and any nonlinear optical process. We use this analysis to design an efficient and robust second harmonic generation, the most widely used nonlinear process for both fundamental and applied research...
January 16, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28081090/enhancement-cavities-for-few-cycle-pulses
#8
N Lilienfein, C Hofer, S Holzberger, C Matzer, P Zimmermann, M Trubetskov, V Pervak, I Pupeza
We address the challenge of increasing the bandwidth of high-finesse femtosecond enhancement cavities and demonstrate a broad spectrum spanning 1800  cm<sup>-1</sup> (195 nm) at -10  dB around a central wavelength of 1050 nm in an EC with an average finesse exceeding 300. This will benefit a host of spectroscopic applications, including transient absorption spectroscopy, direct frequency comb spectroscopy, and Raman spectroscopy. The pulse circulating in the EC is composed of only 5.4 optical cycles, at a kilowatt-level average power...
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28077003/influence-of-extrinsic-inputs-and-synaptic-gains-on-dynamics-of-wendling-s-neural-mass-model-a-bifurcation-analysis
#9
Shujuan Geng, Weidong Zhou
We analyze the neurodynamics attributed by a model proposed by Wendling and co-workers (2002) [Wendling, F., Bartolomei, F., Bellanger, J.J. & Chauvel, P. (2002) Epileptic fast activity can be explained by a model of impaired GABAergic dendritic inhibition. Eur. J. Neurosci., 15, 1499.] to explain several different types of electroencephalographic activities. We could find three principal types of steady states when the system parameters change slowly: (i) the model produce a constant output when it is under a state of stable equilibrium point with a constant input...
January 11, 2017: Journal of Integrative Neuroscience
https://www.readbyqxmd.com/read/28074876/scale-up-of-nature-s-tissue-weaving-algorithms-to-engineer-advanced-functional-materials
#10
Joanna L Ng, Lillian E Knothe, Renee M Whan, Ulf Knothe, Melissa L Knothe Tate
We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently "smart" material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues' biological, mechanical and organizational detail to create advanced functional materials...
January 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28074712/high-throughput-whole-genome-sequencing-of-porcine-reproductive-and-respiratory-syndrome-virus-from-cell-culture-materials-and-clinical-specimens-using-next-generation-sequencing-technology
#11
Jianqiang Zhang, Ying Zheng, Xiao-Qin Xia, Qi Chen, Sarah A Bade, Kyoung-Jin Yoon, Karen M Harmon, Phillip C Gauger, Rodger G Main, Ganwu Li
Next-generation sequencing (NGS) technologies have increasingly played crucial roles in biological and medical research, but are not yet in routine use in veterinary diagnostic laboratories. We developed and applied a procedure for high-throughput RNA sequencing of Porcine reproductive and respiratory syndrome virus (PRRSV) from cell culture-derived isolates and clinical specimens. Ten PRRSV isolates with known sequence information, 2 mixtures each with 2 different PRRSV isolates, and 51 clinical specimens (19 sera, 16 lungs, and 16 oral fluids) with various PCR threshold cycle (Ct) values were subjected to nucleic acid extraction, cDNA library preparation (24-plexed), and sequencing...
January 2017: Journal of Veterinary Diagnostic Investigation
https://www.readbyqxmd.com/read/28067505/iodide-iodates-m3-io3-12%C3%A2-ag4i-m-bi-tb-with-a-framework-structure-and-high-second-harmonic-generation-optical-response
#12
Elena L Belokoneva, Sergey Yu Stefanovich, Olga V Dimitrova, Alina S Karamysheva, Anatoly S Volkov
Single crystals of two new iodide-iodates, Bi3[IO3]12·Ag4I and Tb3[IO3]12·Ag4I, are synthesized in hydrothermal systems. The anionic parts in both iodide-iodates are characterized as a complex charged framework of isolated IO3 umbrella-like groups and large Bi(Tb)-O polyhedra similar to those previously found in La3[IO3]12[IO3](Pb3O). Broad channels along the c-axis contain compensators: (Ag3I)(2+) umbrella-like groups and additional Ag(+) ions which form Ag4(4+) tetrahedral clusters augmented with I(-) halogen...
January 9, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28062031/how-to-measure-load-dependent-kinetics-of-individual-motor-molecules-without-a-force-clamp
#13
J Sung, K I Mortensen, J A Spudich, H Flyvbjerg
Single-molecule force spectroscopy techniques, including optical trapping, magnetic trapping, and atomic force microscopy, have provided unprecedented opportunities to understand biological processes at the smallest biological length scales. For example, they have been used to elucidate the molecular basis of muscle contraction and intracellular cargo transport along cytoskeletal filamentous proteins. Optical trapping is among the most sophisticated single-molecule techniques. With exceptionally high spatial and temporal resolutions, it has been extensively utilized to understand biological functions at the single molecule level, such as conformational changes and force-generation of individual motor proteins or force-dependent kinetics in molecular interactions...
2017: Methods in Enzymology
https://www.readbyqxmd.com/read/28060776/an-electric-field-representation-of-the-harmonic-xy-model
#14
Michael F Faulkner, Steven T Bramwell, Peter C W Holdsworth
The two-dimensional harmonic XY (HXY) model is a spin model in which the classical spins interact via a piecewise parabolic potential. We argue that the HXY model should be regarded as the canonical classical lattice spin model of phase fluctuations in two-dimensional condensates, as it is the simplest model that guarantees the modular symmetry of the experimental systems. Here we formulate a lattice electric-field representation of the HXY model and contrast this with an analogous representation of the Villain model and the two-dimensional Coulomb gas with a purely rotational auxiliary field...
January 6, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28059773/attosecond-physics-at-the-nanoscale
#15
Marcelo F Ciappina, J Perez-Hernandez, Alexandra Landsman, William Okell, Sergey Zherebtsov, Benjamin Förg, Johannes Schötz, Lennart Seiffert, Thomas Fennel, Tahir Shaaran, Tomas Zimmermann, Alexis Chacón, Roland Guichard, Amelle Zair, John Tisch, J Marangos, Tobias Witting, Avi Braun, Stefan Maier, Luis Roso, Michael Krüger, Peter Hommelhoff, Matthias Kling, Ferenc Krausz, Maciej Lewenstein
Recently two emerging areas of research, attosecond and nanoscale physics, have started to come together. Attosecond physics deals with phenomena occurring when ultrashort laser pulses, with duration on the femto- and sub-femtosecond time scales, interact with atoms, molecules or solids. The laser-induced electron dynamics occurs natively on a timescale down to a few hundred or even tens of attoseconds, which is comparable with the optical field. For comparison, the revolution of an electron on a 1s orbital of a hydrogen atom is 152 as...
January 6, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28059529/high-orbital-angular-momentum-harmonic-generation
#16
J Vieira, R M G M Trines, E P Alves, R A Fonseca, J T Mendonça, R Bingham, P Norreys, L O Silva
We identify and explore a high orbital angular momentum (OAM) harmonics generation and amplification mechanism that manipulates the OAM independently of any other laser property, by preserving the initial laser wavelength, through stimulated Raman backscattering in a plasma. The high OAM harmonics spectra can extend at least up to the limiting value imposed by the paraxial approximation. We show with theory and particle-in-cell simulations that the orders of the OAM harmonics can be tuned according to a selection rule that depends on the initial OAM of the interacting waves...
December 23, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/28059393/picosecond-high-power-355-nm-uv-generation-in-cslib-sub-6-sub-o-sub-10-sub-crystal
#17
Kentaro Ueda, Yosuke Orii, Yoshinori Takahashi, George Okada, Yusuke Mori, Masashi Yoshimura
We report third-harmonic generation (THG) at 355 nm in CsLiB<sub>6</sub>O<sub>10</sub> (CLBO) by using sum-frequency mixing process. As a fundamental laser source, we employ a hybrid master oscillator power amplifier (MOPA) system seeded by a gain-switched laser diode (GS-LD) at 1064 nm to produce narrow spectral picosecond pulses. Both CLBO and walk-off compensated prism-coupled CLBO device generate over 30-W output of 355-nm UV lights, which means walk-off effect in CLBO is negligible in the picosecond laser system...
December 26, 2016: Optics Express
https://www.readbyqxmd.com/read/28059279/dispersion-relations-of-refractive-indices-suitable-for-kbe-sub-2-sub-bo-sub-3-sub-f-sub-2-sub-crystal-deep-ultraviolet-applications
#18
Rukang Li, Lirong Wang, Xiaoyang Wang, Guiling Wang, Chuangtian Chen
KBe<sub>2</sub>BO<sub>3</sub>F<sub>2</sub> (KBBF) is the only nonlinear optical crystal available to generate deep-ultraviolet (DUV) laser output by direct harmonic generation. High-precision refractive indices, including in the DUV region, were measured, and starting from a double resonance model of polarizability, new dispersion relations of the refractive indices were deduced from the measured data. The predicted phase matching angles for second-harmonic generation down to 165 nm from the new relations agree well with the previous reported values...
December 20, 2016: Applied Optics
https://www.readbyqxmd.com/read/28059180/thermal-poling-of-silica-optical-fibers-using-liquid-electrodes
#19
F De Lucia, D W Keefer, C Corbari, P J A Sazio
Thermal poling is a well-known technique for inducing second-order nonlinearities in centrosymmetric silica optical fibers. However, some 25 years since its discovery, there still remain a number of issues that prevent the realization of very long length, highly efficient all-fiber nonlinear device applications that include frequency conversion or sources of polarization-entangled photon pairs. In this Letter, we report a thermal poling method that utilizes a novel range of liquid metal and aqueous electrodes embedded into the optical fibers...
January 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28055099/evaluation-of-therapeutic-tissue-crosslinking-txl-for-myopia-using-second-harmonic-generation-signal-microscopy-in-rabbit-sclera
#20
Mariya Zyablitskaya, Anna Takaoka, Emilia L Munteanu, Takayuki Nagasaki, Stephen L Trokel, David C Paik
Purpose: Second harmonic generation signals (SHG) are emitted preferentially from collagenous tissue structures and have been used to evaluate photochemically-induced (CXL) crosslinking changes in the cornea. Since therapeutic tissue crosslinking (TXL) using sodium hydroxymethylglycinate (SMG) of the sclera is a potential treatment for high myopia, we explored the use of SHG microscopy to evaluate the effects. Methods: Single sub-Tenon's (sT) injections (400 μL) using SMG (40-400 mM) were made at the equatorial 12 o'clock position of the right eye of cadaveric rabbit heads (n = 16 pairs)...
January 1, 2017: Investigative Ophthalmology & Visual Science
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