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https://www.readbyqxmd.com/read/28644026/pb0-65mn2-85ga3s8-and-pb0-72mn2-84ga2-95se8-two-quaternary-metal-chalcognides-with-open-tunnel-framework-structures-displaying-intense-second-harmonic-generation-responses-and-interesting-magnetic-properties
#1
Molin Zhou, Xingxing Jiang, Yangwu Guo, Zheshuai Lin, Jiyong Yao, Yicheng Wu
By combining different nonlinear optical-active structural chromophores with transition metal Mn into a crystal structure, two novel quaternary metal chalcogenides Pb0.65Mn2.85Ga3S8 (1) and Pb0.72Mn2.84Ga2.95Se8 (2) were successfully synthesized. Compounds 1 and 2 are isostructural, and they represent a new structure type that crystallizes in the space group P6̅ (No. 174) in the hexagonal system. Their structures feature an interesting three-dimensional open-tunnel framework composed of bridged infinite chains with Pb(2+) cations filling in the biggest tunnels...
June 23, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28641255/piecewise-linear-approximation-of-vector-valued-images-and-curves-via-2nd-order-variational-model
#2
Massimo Zanetti, Lorenzo Bruzzone
Variational models are known to work well for addressing image restoration/regularization problems. However, most of the methods proposed in literature are defined for scalar inputs and are used on multiband images (such as RGB or multispectral imagery) by the composition of a simple band-wise processing. This involves suboptimal results and may introduce artifacts. Only in a few cases variational models are extended to the case of vector-valued inputs. However, the known implementations are restricted to 1st-order models, while 2nd-order models are never considered...
June 16, 2017: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
https://www.readbyqxmd.com/read/28613260/joint-optimization-of-receiver-placement-and-illuminator-selection-for-a-multiband-passive-radar-network
#3
Rui Xie, Xianrong Wan, Sheng Hong, Jianxin Yi
The performance of a passive radar network can be greatly improved by an optimal radar network structure. Generally, radar network structure optimization consists of two aspects, namely the placement of receivers in suitable places and selection of appropriate illuminators. The present study investigates issues concerning the joint optimization of receiver placement and illuminator selection for a passive radar network. Firstly, the required radar cross section (RCS) for target detection is chosen as the performance metric, and the joint optimization model boils down to the partition p-center problem (PPCP)...
June 14, 2017: Sensors
https://www.readbyqxmd.com/read/28598676/spectral-flow-and-global-topology-of-the-hofstadter-butterfly
#4
János K Asbóth, Andrea Alberti
We study the relation between the global topology of the Hofstadter butterfly of a multiband insulator and the topological invariants of the underlying Hamiltonian. The global topology of the butterfly, i.e., the displacement of the energy gaps as the magnetic field is varied by one flux quantum, is determined by the spectral flow of energy eigenstates crossing gaps as the field is tuned. We find that for each gap this spectral flow is equal to the topological invariant of the gap, i.e., the net number of edge modes traversing the gap...
May 26, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28580583/simultaneous-multislice-imaging-for-native-myocardial-t1-mapping-improved-spatial-coverage-in-a-single-breath-hold
#5
Sebastian Weingärtner, Steen Moeller, Sebastian Schmitter, Edward Auerbach, Peter Kellman, Chetan Shenoy, Mehmet Akçakaya
PURPOSE: To develop a saturation recovery myocardial T1 mapping method for the simultaneous multislice acquisition of three slices. METHODS: Saturation pulse-prepared heart rate independent inversion recovery (SAPPHIRE) T1 mapping was implemented with simultaneous multislice imaging using FLASH readouts for faster coverage of the myocardium. Controlled aliasing in parallel imaging (CAIPI) was used to achieve minimal noise amplification in three slices. Multiband reconstruction was performed using three linear reconstruction methods: Slice- and in-plane GRAPPA, CG-SENSE, and Tikhonov-regularized CG-SENSE...
June 5, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28573976/multiband-superconductivity-in-bis2-based-layered-compounds
#6
George B Martins, Griffith Mendonca, Mucio Continentino, Tharnier Oliveira
A mean-field treatment is presented of a square lattice two-orbital-model for BiS2 taking into account intra- and inter-orbital superconductivity. A rich phase diagram involving both types of superconductivity is presented as a function of the ratio between the couplings of electrons in the same and different orbitals (η = VXX/VXY) and electron doping x. With the help of a quantity we call orbital-mixing ratio, denoted as R(φ), the phase diagram is analyzed using a simple and intuitive picture based on how R(φ) varies as electron doping increases...
June 2, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28572665/microscopic-description-of-insulator-metal-transition-in-high-pressure-oxygen
#7
Luis Craco, Mukul S Laad, Stefano Leoni
Unusual metallic states involving breakdown of the standard Fermi-liquid picture of long-lived quasiparticles in well-defined band states emerge at low temperatures near correlation-driven Mott transitions. Prominent examples are ill-understood metallic states in d- and f-band compounds near Mott-like transitions. Finding of superconductivity in solid O2 on the border of an insulator-metal transition at high pressures close to 96 GPa is thus truly remarkable. Neither the insulator-metal transition nor superconductivity are understood satisfactorily...
June 1, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28557055/time-efficient-and-flexible-design-of-optimized-multishell-hardi-diffusion
#8
Jana Hutter, J Donald Tournier, Anthony N Price, Lucilio Cordero-Grande, Emer J Hughes, Shaihan Malik, Johannes Steinweg, Matteo Bastiani, Stamatios N Sotiropoulos, Saad Jbabdi, Jesper Andersson, A David Edwards, Joseph V Hajnal
PURPOSE: Advanced diffusion magnetic resonance imaging benefits from collecting as much data as is feasible but is highly sensitive to subject motion and the risk of data loss increases with longer acquisition times. Our purpose was to create a maximally time-efficient and flexible diffusion acquisition capability with built-in robustness to partially acquired or interrupted scans. Our framework has been developed for the developing Human Connectome Project, but different application domains are equally possible...
May 30, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28556180/multiple-coil-k-space-interpolation-enhances-resolution-in-single-shot-spatiotemporal-mri
#9
Gilad Liberman, Eddy Solomon, Michael Lustig, Lucio Frydman
PURPOSE: Spatio-temporal encoding (SPEN) experiments can deliver single-scan MR images without folding complications and with robustness to chemical shift and susceptibility artifacts. Further resolution improvements are shown to arise by relying on multiple receivers, to interpolate the sampled data along the low-bandwidth dimension. The ensuing multiple-sensor interpolation is akin to recently introduced SPEN interleaving procedures, albeit without requiring multiple shots. METHODS: By casting SPEN's spatial rasterization in k-space, it becomes evident that local k-data interpolations enabled by multiple receivers are akin to real-space interleaving of SPEN images...
May 28, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28553198/a-resilient-non-neuronal-source-of-the-spatiotemporal-lag-structure-detected-by-bold-signal-based-blood-flow-tracking
#10
Toshihiko Aso, Guanhua Jiang, Shin-Ichi Urayama, Hidenao Fukuyama
Recent evidence has suggested that blood oxygenation level-dependent (BOLD) signals convey information about brain circulation via low frequency oscillation of systemic origin (sLFO) that travels through the vascular structure ("lag mapping"). Prompted by its promising application in both physiology and pathology, we examined this signal component using multiple approaches. A total of 30 healthy volunteers were recruited to perform two reproducibility experiments at 3 Tesla using multiband echo planar imaging...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28503672/quantum-fluctuations-beyond-the-gutzwiller-approximation
#11
Michele Fabrizio
We present a simple scheme to evaluate linear response functions including quantum fluctuation corrections on top of the Gutzwiller approximation. The method is derived for a generic multiband lattice Hamiltonian without any assumption about the dynamics of the variational correlation parameters that define the Gutzwiller wavefunction, and which thus behave as genuine dynamical degrees of freedom that add on those of the variational uncorrelated Slater determinant. We apply the method to the standard half-filled single-band Hubbard model...
February 28, 2017: Physical Review. B
https://www.readbyqxmd.com/read/28489539/task-independent-mental-workload-classification-based-upon-common-multi-band-eeg-cortical-connectivity
#12
Georgios Dimitrakopoulos, Ioannis Kakkos, Zhongxiang Dai, Julian Lim, Joshua deSouza, Anastasios Bezerianos, Yu Sun
Efficient classification of mental workload, an important issue in neuroscience, is limited so far to single task, while cross-task classification remains a challenge. Furthermore, network approaches have emerged as a promising direction for studying the complex organization of the brain, enabling easier interpretation of various mental states. In this study, using two mental tasks (N-back and mental arithmetic), we present a framework for cross- as well as within-task workload discrimination by utilizing multiband EEG cortical brain connectivity...
May 4, 2017: IEEE Transactions on Neural Systems and Rehabilitation Engineering
https://www.readbyqxmd.com/read/28489056/meritxell-the-multifrequency-experimental-radiometer-with-interference-tracking-for-experiments-over-land-and-littoral-instrument-description-calibration-and-performance
#13
Jorge Querol, José Miguel Tarongí, Giuseppe Forte, José Javier Gómez, Adriano Camps
MERITXELL is a ground-based multisensor instrument that includes a multiband dual-polarization radiometer, a GNSS reflectometer, and several optical sensors. Its main goals are twofold: to test data fusion techniques, and to develop Radio-Frequency Interference (RFI) detection, localization and mitigation techniques. The former is necessary to retrieve complementary data useful to develop geophysical models with improved accuracy, whereas the latter aims at solving one of the most important problems of microwave radiometry...
May 10, 2017: Sensors
https://www.readbyqxmd.com/read/28468371/numerical-study-of-tunable-enhanced-chirality-in-multilayer-stack-achiral-phase-change-metamaterials
#14
Tun Cao, Yang Li, Chen-Wei Wei, Yi-Mei Qiu
We numerically demonstrate a multiband circular dichroism (CD) by tilting achiral metamaterials (MMs) composed of an elliptical nanoholes array (ENA) penetrating through metal/ phase-change material (PCM) /metal multilayer stack, with respect to the incident light. The CD spectrum can be actively tuned across a wide range from the near-infrared (NIR) to mid-infrared (MIR) regime by transiting the state of the PCM (Ge<sub>2</sub>Sb<sub>2</sub>Te<sub>5</sub>) from amorphous to crystalline...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28464498/minimizing-the-heat-effect-of-photodynamic-therapy-based-on-inorganic-nanocomposites-mediated-by-808-nm-near-infrared-light
#15
Ming-Hsien Chan, Yu-Ting Pan, I-Jung Lee, Chieh-Wei Chen, Yung-Chieh Chan, Michael Hsiao, Feng Wang, Lingdong Sun, Xueyuan Chen, Ru-Shi Liu
Photodynamic therapy (PDT) based on photosensitizers (PSs) constructed with nanomaterials has become popular in cancer treatment, especially oral carcinoma cell. This therapy is characterized by improved PS accumulation in tumor regions and generation of reactive oxygen species (ROS) for PDT under specific excitation. In the selection of near-infrared (NIR) window, 808 nm NIR light because it can avoid the absorption of water is particularly suitable for the application in PDT. Hence, multiband emissions under a single 808 nm near-infrared excitation of Nd(3+) -sensitized upconversion nanoparticles (808 nm UCNPs) have been applied for the PDT effect...
June 2017: Small
https://www.readbyqxmd.com/read/28464456/forward-backward-switching-of-plasmonic-wave-propagation-using-sign-reversal-coupling
#16
Zhen Gao, Fei Gao, Youming Zhang, Hongyi Xu, Yu Luo, Baile Zhang
Backward waves with wave-front propagation opposite in direction to that of energy flow have attracted considerable interest in the context of photonic metamaterials. However, switching between forward and backward waves in the same frequency range has remained a challenge. Here, on a platform of coupled designer surface plasmon resonators in the microwave regime, multiband forward/backward switching of plasmonic wave propagation is demonstrated. This approach makes use of sign-reversal coupling that occurs when switching the coupling configuration between tightly confined photonic modes...
May 2, 2017: Advanced Materials
https://www.readbyqxmd.com/read/28460843/interest-of-decompression-in-orthodontics-case-report-of-a-keratocyst-during-childhood
#17
Alexandre Alpy, Laurianne Tournaire, Fréderic Vaysse, Christine Marchal-Sixou, Arnaud Lhomme, Bruno Courtois
Keratocysts, also known as keratocystic odontogenic tumors (KCOT), make up 7% of all odontogenic cysts and develop asymptomatically in most cases. Enucleation is the benchmark treatment. However, there are surgical alternatives. Marsupialization and decompression are necessary in some cases, mainly when the KCOT is large, thus causing an increased risk of bone fracture, or if it has engulfed important elements such as the inferior alveolar nerve or teeth, consequently causing alveolar bone growth failure. The authors describe the case of a nine-year-old child treated for a large keratocyst situated in sector 4 (lower right jaw), impacting both premolars and the canine (45, 44 and 43)...
April 28, 2017: International Orthodontics
https://www.readbyqxmd.com/read/28439547/tuning-across-the-bcs-bec-crossover-in-the-multiband-superconductor-fe1-y-se-x-te1-x-an-angle-resolved-photoemission-study
#18
Shahar Rinott, K B Chashka, Amit Ribak, Emile D L Rienks, Amina Taleb-Ibrahimi, Patrick Le Fevre, François Bertran, Mohit Randeria, Amit Kanigel
The crossover from Bardeen-Cooper-Schrieffer (BCS) superconductivity to Bose-Einstein condensation (BEC) is difficult to realize in quantum materials because, unlike in ultracold atoms, one cannot tune the pairing interaction. We realize the BCS-BEC crossover in a nearly compensated semimetal, Fe1+y Se x Te1-x , by tuning the Fermi energy εF via chemical doping, which permits us to systematically change Δ/εF from 0.16 to 0.50, where Δ is the superconducting (SC) gap. We use angle-resolved photoemission spectroscopy to measure the Fermi energy, the SC gap, and characteristic changes in the SC state electronic dispersion as the system evolves from a BCS to a BEC regime...
April 2017: Science Advances
https://www.readbyqxmd.com/read/28437916/multiband-selective-absorbers-made-of-1d-periodic-ag-sio-sub-2-sub-ag-core-shell-coaxial-cylinders-horizontally-lying-on-a-planar-substrate
#19
Yi Zhao, Ceji Fu
In this paper, we present a one-dimensional periodic microstructure for multiband selective absorbers of thermal radiation. The microstructure is made of Ag/SiO<sub>2</sub>/Ag core/shell coaxial cylinders horizontally lying on top of a SiO<sub>2</sub> dielectric spacer and an opaque silver substrate. The spectral-directional absorptivity of the proposed structure was numerically investigated with the finite element based Comsol Multiphysics software. Multiband selective absorption in the wavenumber range from 2500 to 20000 cm<sup>-1</sup> for TM-wave incidence was obtained...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28414374/practical-dual-band-terahertz-imaging-system
#20
Deliang Zhou, Liwei Hou, Wei Xie, Yuanzhang Zang, Bin Lu, Jian Chen, Peiheng Wu
This paper introduces a dual-band terahertz imaging system as a potential product for nondestructive testing using heterodyne detectors and continuous-wave sources. The operating frequencies of the system are 110.4 and 220.8 GHz. Multiband fusion technology combines the advantages of the greater spatial resolution of the high-frequency band and the enhanced sensitivity of the low-frequency band to improve the detection ability of the system. Additionally, the interference cancellation technology is used to obtain a superior image quality...
April 10, 2017: Applied Optics
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