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Janina Wirth, Kory K Green, Megan O'Connor, Shuang F Lim
Upconverting nanoparticles show potential applications in the field of photovoltaics and array-based detection devices. While fluorescence enhancement using interference of incident radiation is well known in Stokes-shift type systems such as fluorescent dyes; the effect of such interference geometry in nonlinear Anti-Stokes type emission, such as in upconversion rare earth photophysics is demonstrated for the first time. This work describes in detail the influence of the interference modulation on both the excitation (interion energy transfer) and radiative decay with nonradiative decay processes active between emissive levels...
December 2, 2016: Small
Fei Gao, Linyi Bai, Siyu Liu, Ruochong Zhang, Jingtao Zhang, Xiaohua Feng, Yuanjin Zheng, Yanli Zhao
Photoacoustic tomography has emerged as a promising non-invasive imaging technique that integrates the merits of high optical contrast with high ultrasound resolution in deep scattering medium. Unfortunately, the blood background in vivo seriously impedes the quality of imaging due to its comparable optical absorption with contrast agents, especially in conventional linear photoacoustic imaging modality. In this study, we demonstrated that two hybrids consisting of gold nanorods (Au NRs) and zinc tetra(4-pyridyl)porphyrin (ZnTPP) exhibited a synergetic effect in improving optical absorption, conversion efficiency from light to heat, and thermoelastic expansion, leading to a notable enhancement in both linear (four times greater) and nonlinear (more than six times) photoacoustic signals as compared with conventional Au NRs...
December 2, 2016: Nanoscale
Yingmei Wang, Ge Wang, Shuwei Mao, Wenxiang Cong, Zhilong Ji, Jian-Feng Cai, Yangbo Ye
Reducing radiation dose is an important goal in medical computed tomography (CT), for which interior tomography is an effective approach. There have been interior reconstruction algorithms for monochromatic CT, but in reality, X-ray sources are polychromatic. Using a polychromatic acquisition model and motivated by framelet-based image processing algorithms, in this paper, we propose an interior reconstruction algorithm to obtain an image with spectral information assuming only one scan with a current energy-integrating detector...
November 22, 2016: Journal of X-ray Science and Technology
Hassan Aghdasinia, Parvin Arehjani, Behrouz Vahid, Alireza Khataee
Optimization of Acid Orange 7 (AO7) treatment using heterogeneous Fenton-like method in a recirculating fluidized-bed reactor (FBR) was investigated by central composite design (CCD). Natural magnetite (NM) as Fenton-like catalyst was characterized using scanning electron microscopy (SEM). Nonlinear CCD model was obtained for prediction of dye degradation as a function of experimental variables such as peroxydisulfate concentration (0.1-0.5 mmol/L), initial AO7 concentration (5-25 mg/L), pH (3-9) and NM dosage (0...
December 2, 2016: Environmental Technology
Daniel McNeish, Denis Dumas
Recent methodological work has highlighted the promise of nonlinear growth models for addressing substantive questions in the behavioral sciences. In this article, we outline a second-order nonlinear growth model in order to measure a critical notion in development and education: potential. Here, potential is conceptualized as having three components-ability, capacity, and availability-where ability is the amount of skill a student is estimated to have at a given timepoint, capacity is the maximum amount of ability a student is predicted to be able to develop asymptotically, and availability is the difference between capacity and ability at any particular timepoint...
December 2, 2016: Multivariate Behavioral Research
Dong Hu, Xiaping Fu, Xueming He, Yibin Ying
Spatial-frequency domain imaging (SFDI), as a noncontact, low-cost and wide-field optical imaging technique, offers great potential for agro-product safety and quality assessment through optical absorption (μa) and scattering (μ) property measurements. In this study, a laboratory-based SFDI system was constructed and developed for optical property measurement of fruits and vegetables. The system utilized a digital light projector to generate structured, periodic light patterns and illuminate test samples...
December 2, 2016: Scientific Reports
Seung Hun Lee, J H Lee, I Yamada, Jae Sun Park
Neural networks provide powerful approaches of dealing with nonlinear data and have been successfully applied to fusion plasma diagnostics and control systems. Controlling tokamak plasmas in real time is essential to measure the plasma parameters in situ. However, the χ(2) method traditionally used in Thomson scattering diagnostics hampers real-time measurement due to the complexity of the calculations involved. In this study, we applied a neural network approach to Thomson scattering diagnostics in order to calculate the electron temperature, comparing the results to those obtained with the χ(2) method...
November 2016: Review of Scientific Instruments
K Barada, T L Rhodes, N A Crocker, W A Peebles
We present new measurements of internal magnetic fluctuations obtained with a novel eight channel cross polarization scattering (CPS) system installed on the DIII-D tokamak. Measurements of internal, localized magnetic fluctuations provide a window on an important physics quantity that we heretofore have had little information on. Importantly, these measurements provide a new ability to challenge and test linear and nonlinear simulations and basic theory. The CPS method, based upon the scattering of an incident microwave beam into the opposite polarization by magnetic fluctuations, has been significantly extended and improved over the method as originally developed on the Tore Supra tokamak...
November 2016: Review of Scientific Instruments
I Ďuran, S Entler, M Kohout, M Kočan, G Vayakis
Performance of bismuth Hall sensors developed for the ITER steady state magnetic diagnostic was investigated for high magnetic fields in the range ±7 T. Response of the sensors to the magnetic field was found to be nonlinear particularly within the range ±1 T. Significant contribution of the planar Hall effect to the sensors output voltage causing undesirable cross field sensitivity was identified. It was demonstrated that this effect can be minimized by the optimization of the sensor geometry and alignment with the magnetic field and by the application of "current-spinning technique...
November 2016: Review of Scientific Instruments
W Lee, J Leem, G S Yun, H K Park, S H Ko, W X Wang, R V Budny, N C Luhmann, K W Kim
Ion gyroscale turbulent fluctuations with the poloidal wavenumber kθ ∼ 3 cm(-1) have been measured in the core region of the neutral beam (NB) injected low confinement (L-mode) plasmas on Korea superconducting tokamak advanced research. The turbulence poloidal wavenumbers are deduced from the frequencies and poloidal rotation velocities in the laboratory frame, measured by the multichannel microwave imaging reflectometer. Linear and nonlinear gyrokinetic simulations also predict the unstable modes with the normalized wavenumber kθρs ∼ 0...
November 2016: Review of Scientific Instruments
Qi Wang, Zhijie Lian, Jianming Wang, Qingliang Chen, Yukuan Sun, Xiuyan Li, Xiaojie Duan, Ziqiang Cui, Huaxiang Wang
Electrical impedance tomography (EIT) reconstruction is a nonlinear and ill-posed problem. Exact reconstruction of an EIT image inverts a high dimensional mathematical model to calculate the conductivity field, which causes significant problems regarding that the computational complexity will reduce the achievable frame rate, which is considered as a major advantage of EIT imaging. The single-step method, state estimation method, and projection method were always used to accelerate reconstruction process. The basic principle of these methods is to reduce computational complexity...
November 2016: Review of Scientific Instruments
Justin Beroz, A John Hart
The handheld micropipette is the most ubiquitous instrument for precision handling of microliter-milliliter liquid volumes, which is an essential capability in biology and chemistry laboratories. The range of one pipette is typically adjustable up to 10-fold its minimum volume, requiring the use and maintenance of multiple pipettes for liquid handling across larger ranges. Here we propose a design for a single handheld pipette adjustable from 0.1 μl to 1000 μl (i.e., 10(4)-fold) which spans the range of an entire suite of current commercial pipettes...
November 2016: Review of Scientific Instruments
M J Yang, Z M Zhang, Y J Wang, D W Li, W Zhou, H H Tang, Y T Liu, P Chai, L Shuai, X C Huang, S Q Liu, M L Zhu, X P Jiang, Y W Zhang, T Li, B Ma, S F Sun, L Y Sun, Q Wang, Z R Lu, T Zhang, L Wei
An instrument used for measuring multiple scintillators' light output and energy resolution was developed. The instrument consisted of a light sensor array which was composed of 64 discrete SiPMs (Silicon Photomultipliers), a corresponding individual channel readout electronics system, and a data processing algorithm. A Teflon grid and a large interval between adjacent SiPMs were employed to eliminate the optical cross talk among scintillators. The scintillators' light output was obtained by comparing with a reference sample with known light output...
November 2016: Review of Scientific Instruments
Liming Wu, Hua Lin, Yu-Jun Zheng, Xiao-Ning Hu, Hong Chen, Ju-Song Yu
Two new non-centrosymmetric polar quaternary selenides, namely, RbZn4In5Se12 and CsZn4In5Se12, have been synthesized and structurally characterized. They exhibit 3D diamond-like framework (DLF) consisting of corner shared MSe4 (M = Zn/In) tetrahedra, in which the A+ ions are located. Both compounds are thermally stable up to 1300 K and exhibit large transmittance in the infrared region (0.65-25 μm) with measured optical band gaps of 2.06 eV for RbZn4In5Se12 and 2.11 eV for CsZn4In5Se12. Inspiringly, they exhibit good balance between strong second harmonic generation (SHG) efficiency (3...
December 1, 2016: Chemistry, An Asian Journal
James C Moreland, Geoffrey M Boynton
Observers show small but systematic deviations from equal weighting of all elements when asked to localize the center of an array of dots. Counter-intuitively, with small numbers of dots drawn from a Gaussian distribution, this bias results in subjects overweighting the influence of outlier dots - inconsistent with traditional statistical estimators of central tendency. Here we show that this apparent statistical anomaly can be explained by the observation that outlier dots also lie in regions of lower dot density...
December 1, 2016: Attention, Perception & Psychophysics
Can Wang, Jianxin Peng, Lijuan Song, Xiaowen Zhang
Obstructive sleep apnea hypopnea syndrome (OSAHS) is a serious respiratory disorder. Snoring is the most intuitively characteristic symptom of OSAHS. Recently, many studies have attempted to develop snore analysis technology for diagnosing OSAHS. The preliminary and essential step in such diagnosis is to automatically segment snoring sounds from original sleep sounds. This study presents an automatic snoring detection algorithm that detects potential snoring episodes using an adaptive effective-value threshold method, linear and nonlinear feature extraction using maximum power ratio, sum of positive/negative amplitudes, 500 Hz power ratio, spectral entropy (SE) and sample entropy (SampEn), and automatic snore/nonsnore classification using a support vector machine...
December 1, 2016: Australasian Physical & Engineering Sciences in Medicine
Horacio G Rotstein
The generation of intrinsic subthreshold (membrane potential) oscillations (STOs) in neuronal models requires the interaction between two processes: a relatively fast positive feedback that favors changes in voltage and a slower negative feedback that opposes these changes. These are provided by the so-called resonant and amplifying gating variables associated to the participating ionic currents. We investigate both the biophysical and dynamic mechanisms of generation of STOs and how their attributes (frequency and amplitude) depend on the model parameters for biophysical (conductance-based) models having qualitatively different types of resonant currents (activating and inactivating) and an amplifying current...
December 1, 2016: Journal of Computational Neuroscience
Wei Dong
Sound energy propagates in the cochlea through a forward-traveling or slow wave supported by the cochlear partition and fluid inertia. Additionally, cochlear models support traveling wave propagation in the reverse direction as the expected mechanism for conveying otoacoustic emissions out of the cochlea. Recently, however, this hypothesis has been questioned, casting doubt on the process by which otoacoustic emissions travel back out through the cochlea. The proposed alternative reverse travel path for emissions is directly through the fluids of the cochlea as a compression pressure in the form of a fast wave...
December 1, 2016: Journal of the Association for Research in Otolaryngology: JARO
Alexander S Mathew, Christopher A DeRosa, James N Demas, Cassandra L Fraser
Lifetime-based oxygen imaging is useful in many biological applications but instrumentation can be stationary, expensive, and complex. Herein, we present a portable, cost effective, simple alternative with high spatiotemporal resolution that uses a complementary metal oxide silicon (CMOS) camera to measure oxygen sensitive lifetimes on the millisecond scale. We demonstrate its compatibility with difluoroboron β-diketonate poly(lactic acid) (BF2bdkPLA) polymers which are nontoxic and exhibit long-lived oxygen sensitive phosphorescence...
April 21, 2016: Analytical Methods: Advancing Methods and Applications
Yun-An Yan
Over decades, the theoretical study of the quantum dissipative dynamics was mainly based on the linear dissipation model. The study of the nonlinear dissipative dynamics in condensed phases, where there exist an infinite number of bath modes, is extremely difficult even if not impossible. This work put forward a stochastic scheme for the simulation of the nonlinear dissipative dynamics. In the linear response regime, the second-order cumulant expansion becomes exact to reproduce the effect of the bath on the evolution of the reduced system...
November 28, 2016: Journal of Chemical Physics
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