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Zhengcui Wu, Yejing Xue, Zexian Zou, Xia Wang, Feng Gao
Crystal facet engineering and surface modification of semiconductor have become important strategies to improve photocatalytic activity by optimizing surface charge carrier separation/transfer and extending solar spectrum utilization. In this work, we report anatase single-crystalline TiO2 hollow tetragonal nanocones with large exposed (101) facets by a facile liquid-phase interfacial synthetic strategy, using the hydrolysis of tetrabutyltitanate with adscititious water in the organic solvent of cyclohexane and a capping agent of 1, 6-hexanediamine...
November 23, 2016: Journal of Colloid and Interface Science
Jia Li, Chenyan Bai, Zhouchen Lin, Jian Yu
In most of existing digital cameras, color images have to be reconstructed from raw images which only have one color sensed at each pixel, as their imaging sensors are covered by color filter arrays (CFAs). At each pixel a CFA usually allows only a portion of the light spectrum to pass through and thereby reduces the light sensitivity of pixels. To address this issue, previous works have explored adding panchromatic pixels into CFAs. However, almost all existing methods assign panchromatic pixels empirically, making the designed CFAs prone to aliasing artifacts...
December 1, 2016: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
E Civardi, M Moroni, M Babij, Z Bukowski, P Carretta
^{75}As, ^{87}Rb, and ^{85}Rb nuclear quadrupole resonance (NQR) and ^{87}Rb nuclear magnetic resonance measurements in a RbFe_{2}As_{2} iron-based superconductor are presented. We observe a marked broadening of the ^{75}As NQR spectrum below T_{0}≃140  K which is associated with the onset of a charge order in the FeAs planes. Below T_{0} we observe a power-law decrease in the ^{75}As nuclear spin-lattice relaxation rate down to T^{*}≃20  K. Below T^{*} the nuclei start to probe different dynamics owing to the different local electronic configurations induced by the charge order...
November 18, 2016: Physical Review Letters
Dekai Zhou, Yuguang C Li, Pengtao Xu, Nicholas S McCool, Longqiu Li, Wei Wang, Thomas E Mallouk
Visible light driven Cu2O-Au micromotors exhibit rapid on/off switching and speed control. Electrochemical measurements confirm that the light-induced movement of the Cu2O-Au micromotors involves a self-electrophoresis mechanism modulated by the photoconductivity of Cu2O. This study extends the utilization of the electromagnetic spectrum for micro/nanomotors into the visible range.
December 2, 2016: Nanoscale
S D Scott, R T Mumgaard
A tokamak-independent analysis suite has been developed to process data from Motional Stark Effect (mse) diagnostics. The software supports multi-spectral line-polarization mse diagnostics which simultaneously measure emission at the mse σ and π lines as well as at two "background" wavelengths that are displaced from the mse spectrum by a few nanometers. This analysis accurately estimates the amplitude of partially polarized background light at the σ and π wavelengths even in situations where the background light changes rapidly in time and space, a distinct improvement over traditional "time-interpolation" background estimation...
November 2016: Review of Scientific Instruments
R T Mumgaard, S D Scott, M Khoury
A multi-spectral line-polarization motional Stark effect (MSE-MSLP) diagnostic has been developed for the Alcator C-Mod tokamak wherein the Stokes vector is measured in multiple wavelength bands simultaneously on the same sightline to enable better polarized background subtraction. A ten-sightline, four wavelength MSE-MSLP detector system was designed, constructed, and qualified. This system consists of a high-throughput polychromator for each sightline designed to provide large étendue and precise spectral filtering in a cost-effective manner...
November 2016: Review of Scientific Instruments
S Z Kubala, M T Borchardt, D J Den Hartog, D J Holly, C M Jacobson, L A Morton, W C Young
The Thomson scattering diagnostic on MST records both equilibrium and fluctuating electron temperature with a range capability of 10 eV-5 keV. Standard operation with two modified commercial Nd:YAG lasers allows measurements at rates of 1 kHz-25 kHz. Several subsystems of the diagnostic are being improved. The power supplies for the avalanche photodiode detectors (APDs) that record the scattered light are being replaced to improve usability, reliability, and maintainability. Each of the 144 APDs will have an individual rack mounted switching supply, with bias voltage adjustable to match the APD...
November 2016: Review of Scientific Instruments
Y M Hou, C R Wu, J Huang, W W Heidbrink, M G von Hellermann, Z Xu, Z Jin, J F Chang, Y B Zhu, W Gao, Y J Chen, B Lyu, R J Hu, P F Zhang, L Zhang, W Gao, Z W Wu, Y Yu, M Y Ye
In toroidal magnetic fusion devices, fast-ion D-alpha diagnostic (FIDA) is a powerful method to study the fast-ion feature. The fast-ion characteristics can be inferred from the Doppler shifted spectrum of Dα light according to charge exchange recombination process between fast ions and probe beam. Since conceptual design presented in the last HTPD conference, significant progress has been made to apply FIDA systems on the Experimental Advanced Superconducting Tokamak (EAST). Both co-current and counter-current neutral beam injectors are available, and each can deliver 2-4 MW beam power with 50-80 keV beam energy...
November 2016: Review of Scientific Instruments
L B Fletcher, U Zastrau, E Galtier, E J Gamboa, S Goede, W Schumaker, A Ravasio, M Gauthier, M J MacDonald, Z Chen, E Granados, H J Lee, A Fry, J B Kim, C Roedel, R Mishra, A Pelka, D Kraus, B Barbrel, T Döppner, S H Glenzer
We present the first spectrally resolved measurements of x-rays scattered from cryogenic hydrogen jets in the single photon counting limit. The 120 Hz capabilities of the LCLS, together with a novel hydrogen jet design [J. B. Kim et al., Rev. Sci. Instrum. (these proceedings)], allow for the ability to record a near background free spectrum. Such high-dynamic-range x-ray scattering measurements enable a platform to study ultra-fast, laser-driven, heating dynamics of hydrogen plasmas. This measurement has been achieved using two highly annealed pyrolytic graphite crystal spectrometers to spectrally resolve 5...
November 2016: Review of Scientific Instruments
Yinan Zhou, Li Gao, Jiefeng Huang, Qingshuang Qiu, Ge Zhuang
An infrared multi-channel Thomson scattering diagnostic system is designed from the viewpoint of development of the proposed system on the Joint Texas Experimental Tokamak (J-TEXT). A 3 J/50 Hz Nd:YAG laser, which is injected vertically into plasma in the direction from top to bottom, serves as the power source of the system. The scattering light is then collected horizontally and is transmitted to an interference-filter avalanche photodiode based polychromater for spectrum analysis. The system covers the half plasma cross section, providing 14 spatial points with 2 cm resolution...
November 2016: Review of Scientific Instruments
Y Kim, H W Herrmann, A M McEvoy, C S Young, C Hamilton, D D Schwellenbach, R M Malone, M I Kaufman, A S Smith
An aerogel Cherenkov detector is proposed to measure the X-ray energy spectrum from the Cygnus-intense flash X-ray source operated at the Nevada National Security Site. An array of aerogels set at a variety of thresholds between 1 and 3 MeV will be adequate to map out the bremsstrahlung X-ray production of the Cygnus, where the maximum energy of the spectrum is normally around 2.5 MeV. In addition to the Cherenkov radiation from aerogels, one possible competing light-production mechanism is optical transition radiation (OTR), which may be significant in aerogels due to the large number of transitions from SiO2 clusters to vacuum voids...
November 2016: Review of Scientific Instruments
F Glass, T N Carlstrom, D Du, A G McLean, D A Taussig, R L Boivin
A design to extend the unique divertor Thomson scattering system on DIII-D to allow measurements of electron temperature and density in high triangularity plasmas is presented. Access to this region is selectable on a shot-by-shot basis by redirecting the laser beam of the existing divertor Thomson system inboard - beneath the lower floor using a moveable, high-damage threshold, in-vacuum mirror - and then redirecting again vertically. The currently measured divertor region remains available with this mirror retracted...
November 2016: Review of Scientific Instruments
J Huang, W W Heidbrink, M G von Hellermann, L Stagner, C R Wu, Y M Hou, J F Chang, S Y Ding, Y J Chen, Y B Zhu, Z Jin, Z Xu, W Gao, J F Wang, B Lyu, Q Zang, G Q Zhong, L Hu, B Wan
To investigate the fast ion behavior, a fast ion D-alpha (FIDA) diagnostic system has been installed on EAST. Fast ion features can be inferred from the Doppler shifted spectrum of Balmer-alpha light from energetic hydrogenic atoms. This paper will focus on the validation of FIDA measurements performed using MHD-quiescent discharges in 2015 campaign. Two codes have been applied to calculate the Dα spectrum: one is a Monte Carlo code, Fortran 90 version FIDASIM, and the other is an analytical code, Simulation of Spectra (SOS)...
November 2016: Review of Scientific Instruments
Alexander Dontsov, Anna Koromyslova, Mikhail Ostrovsky, Natalia Sakina
AIM: To investigate the effect of two ways of lipofuscin production (lipid peroxidation and glycation) on lipofuscin fluorescence characteristics and phototoxicity and to compare them with the properties of natural lipofuscin. METHODS: Model lipofuscins were prepared on the basis of bovine photoreceptor outer segments (POS) with bisretinoid A2E addition. One set of samples was prepared from POS modified by lipid peroxidation, while another set from POS modified by glycation with fructose...
November 20, 2016: World Journal of Experimental Medicine
David Costley, Heather Nesbitt, Nigel Ternan, James Dooley, Ying-Ying Huang, Michael R Hamblin, Anthony P McHale, John F Callan
Combating antimicrobial resistance is one of the most serious public health challenges facing society today. The development of new antibiotics or alternative techniques that can help combat antimicrobial resistance is being prioritised by many governments and stakeholders across the globe. Antimicrobial photodynamic therapy is one such technique that has received considerable attention but is limited by the inability of light to penetrate through human tissue, reducing its effectiveness when used to treat deep-seated infections...
November 17, 2016: International Journal of Antimicrobial Agents
Nan Wang, Kai Ren, Rong Jia, Wenting Chen, Ruirui Sun
BACKGROUND: Manganese peroxidase (MnP) from Irpex lacteus F17 has been shown to have a strong ability to degrade recalcitrant aromatic pollutants. In this study, a recombinant MnP from I. lacteus F17 was expressed in Escherichia coli Rosetta (DE3) in the form of inclusion bodies, which were refolded to achieve an active enzyme. Further, we optimized the in vitro refolding conditions to increase the recovery yield of the recombinant protein production. Additionally, we attempted to express recombinant MnP in soluble form in E...
December 1, 2016: BMC Biotechnology
Alicia Rae Welden, Alexander A Rusakov, Dominika Zgid
Including finite-temperature effects from the electronic degrees of freedom in electronic structure calculations of semiconductors and metals is desired; however, in practice it remains exceedingly difficult when using zero-temperature methods, since these methods require an explicit evaluation of multiple excited states in order to account for any finite-temperature effects. Using a Matsubara Green's function formalism remains a viable alternative, since in this formalism it is easier to include thermal effects and to connect the dynamic quantities such as the self-energy with static thermodynamic quantities such as the Helmholtz energy, entropy, and internal energy...
November 28, 2016: Journal of Chemical Physics
Michael Stöger-Pollach, Lukáš Kachtík, Bernhard Miesenberger, Philipp Retzl
The excitation probability of transition radiation is measured for varying beam energies in a transmission electron microscope once using optical spectrometry of the emitted light and second using electron energy loss spectrometry. In both cases similar results are found being in good agreement with theory. The knowledge about this probability enables us to judge whether or not transition radiation has to be considered in EELS and CL data interpretation. Additionally it is shown that the emission of transition radiation happens at the sample surfaces only, when the electron passes the vacuum/sample interface and thus feeling the change of its dielectric environment...
November 23, 2016: Ultramicroscopy
T Trevor Caughlin, Sarah J Graves, Gregory P Asner, Michiel van Breugel, Jefferson S Hall, Roberta E Martin, Mark S Ashton, Stephanie A Bohlman
Remote sensing is increasingly needed to meet the critical demand for estimates of forest structure and composition at landscape to continental scales. Hyperspectral images can detect tree canopy properties, including species identity, leaf chemistry and disease. Tree growth rates are related to these measurable canopy properties but whether growth can be directly predicted from hyperspectral data remains unknown. We used a single hyperspectral image and light detection and ranging-derived elevation to predict growth rates for 20 tropical tree species planted in experimental plots...
December 2016: Ecological Applications: a Publication of the Ecological Society of America
Feng Tian, Hisashi Sumikura, Eiichi Kuramochi, Hideaki Taniyama, Masato Takiguchi, Masaya Notomi
Optomechanical control of on-chip emitters is an important topic related to integrated all-optical circuits. However, there is neither a realization nor a suitable optomechanical structure for this control. The biggest obstacle is that the emission signal can hardly be distinguished from the pump light because of the several orders' power difference. In this study, we designed and experimentally verified an optomechanical oscillation system, in which a lumped mechanical oscillator connected two optically isolated pairs of coupled one-dimensional photonic crystal cavities...
November 28, 2016: Optics Express
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