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Light trap

Ramaz Khomeriki, Levan Chotorlishvili, Igor Tralle, Jamal Berakdar
We uncover and identify the regime for a magnetically and ferroelectrically controllable negative refraction of light traversing multiferroic, oxide-based metastructure consisting of alternating nanoscopic ferroelectric (SrTiO2) and ferromagnetic (Y3Fe2(FeO4)3, YIG) layers. We perform analytical and numerical simulations based on discretized, coupled equations for the self-consistent Maxwell/ferroelectric/ferromagnetic dynamics and obtain a biquadratic relation for the refractive index. Various scenarios of ordinary and negative refraction in different frequency ranges are analyzed and quantified by simple analytical formula that are confirmed by full-fledge numerical simulations...
October 25, 2016: Nano Letters
Jianyan Ding, Quansheng Wu, Yanyan Li, Qiang Long, Yichao Wang, Xinlong Ma, Yuhua Wang
Defect luminescence has been considered to be one of the most efficient ways to resolve the problem of the recent limited supply and increased demand for rare-earth elements. So, in this work, a novel self-activated long-persistent green-yellow and yellow emitting phosphors of α-Ca3B2N4 and β-Ca3B2N4 has been successfully synthesized by sample-pressuring sintering. The α-Ca3B2N4 and β-Ca3B2N4 all have a broad excitation band peaked at 300 and 350 nm and emit yellow-green light peaked at 550 nm and yellow light peaked at 575 nm respectively with the long afterglow properties...
October 25, 2016: Inorganic Chemistry
Hong Ji, Jocelyn M Biagini Myers, Eric B Brandt, Cole Brokamp, Patrick H Ryan, Gurjit K Khurana Hershey
Exposure to traffic-related air pollution (TRAP) has been implicated in asthma development, persistence, and exacerbation. This exposure is highly significant as large segments of the global population resides in zones that are most impacted by TRAP and schools are often located in high TRAP exposure areas. Recent findings shed new light on the epigenetic mechanisms by which exposure to traffic pollution may contribute to the development and persistence of asthma. In order to delineate TRAP induced effects on the epigenome, utilization of newly available innovative methods to assess and quantify traffic pollution will be needed to accurately quantify exposure...
2016: Allergy, Asthma, and Clinical Immunology
Solomon Yared, Araya Gebresilassie, Essayas Akililu, Meshesha Balkew, Alon Warburg, Asrat Hailu, Teshome Gebre-Michael
Visceral leishmaniasis is a significant public health problem in northwest Ethiopia, particularly in Kafta Humera district. The study was designed to determine the species composition and population dynamics of sand flies in five villages representing urban and semi-urban areas of Kafta Humera district namely, Setit Humera, Mykadra, Rawyan, Bereket and Adebay. Sand flies were collected for two to three nights monthly from May 2011 to April 2012 using CDC light-traps and sticky traps. Traps were placed in villages, at periphery of villages and farm fields...
October 19, 2016: Acta Tropica
A W Carr, M Saffman
We analyze doubly magic trapping of Cs hyperfine transitions including previously neglected contributions from the ground state hyperpolarizability and the interaction of the laser light and a static magnetic field. Extensive numerical searches do not reveal any doubly magic trapping conditions for any pair of hyperfine states. However, including the hyperpolarizability reveals light intensity insensitive traps for a wide range of wavelengths at specific intensities. We then investigate the use of bichromatic trapping light fields...
October 7, 2016: Physical Review Letters
Subhadip Goswami, Lin Ma, Alex B F Martinson, Michael R Wasielewski, Omar K Farha, Joseph T Hupp
Owing to their ability to act as light-harvesting scaffolds, porphyrin-containing metal-organic frameworks (MOFs) are in the forefront of research on the application of highly ordered molecular materials to problems in solar-energy conversion. In this work, solvent assisted linker exchange (SALE) is performed on a pillared paddlewheel porphyrin containing MOF thin film to collapse a 3D-framework to a 2D-framework. The change in dimensionality of the framework is confirmed by a decrease in the film thickness, the magnitude of which is in agreement with crystallographic parameters for related bulk materials...
October 21, 2016: ACS Applied Materials & Interfaces
Cercis Morera-Boado, Marco Martínez González, Ramon Alain Miranda-Quintana, Margarita Suarez, Roberto Martinez-Alvarez, Nazario Martín, Jose M Garcia de la Vega
The retro-cycloaddition thermal reaction of isoxazolino[4,5:1,2][60]fullerenes to pristine fullerene seems to be guided by the electronic nature of the substituted nitrile oxide 1,3-dipole in the isoxazoline ring. Trapping experiments proved that the reaction mechanism occurs by thermal removal of the nitrile oxide 1,3-dipole in a process that is favored in the presence of a big excess of a highly efficient dipolarophile, such as maleic anhydride. Theoretical gas phase calculations carried out at the B3LYP/6-31G(d) and M06-2X/6-31G(d) levels of theory underpin the experimental findings and predict that compound 1c, bearing the p-(CH3)2N-Ph substituent on the isoxazoline ring and with an experimental remarkable conversion efficiency in just 12 hours, showed the lowest activation energies...
October 20, 2016: Journal of Physical Chemistry. A
Hui-Hsu Gavin Tsai, Jia-Cheng Hu, Chun-Jui Tan, Yung-Ching Sheng, Chih-Chiang Chiu
The loading of dye sensitizers on a semiconductor is crucial for determining the light harvesting efficiency of dye-sensitizer solar cells (DSSCs). The interfacial properties of dyes adsorbed on TiO2 film such as adsorption configurations and adsorption energy can influence the total amount of dye sensitizers that loads and the stability of a DSSC device. Therefore, it is important to characterize the adsorption properties of dye sensitizers on TiO2 film atomically and electronically to ensure rational structure-based dye design for high-performance DSSCs...
October 20, 2016: Journal of Physical Chemistry. A
Amit Lerner, Howard I Browman
Both attraction and repulsion from linearly polarized light have been observed in zooplankton. A dichotomous choice experiment, consisting of plankton light traps deployed in natural waters at a depth of 30 m that projected either polarized or unpolarized light of the same intensity, was used to test the hypothesis that the North Atlantic copepod, Calanus spp., is linearly polarotactic. In addition, the transparency of these copepods, as they might be seen by polarization insensitive vs. sensitive visual systems, was measured...
October 20, 2016: Scientific Reports
Meizhen Yin, Baozhong Lü, Shusen You, Pengyu Li, Chen Li, Klaus Müllen
Supramolecular self-assembly has attracted increasing attention as a breakthrough methodology in the fields of nanoscience and nanotechnology. In this study, a perylene dianhydride derivative (TP-PDA) self-assembles into well-defined nanospheres through a nucleation-growth process. The mechanisms of this process are explored by spectral ananlysis, dynamic light scattering (DLS) and scanning electron microscopy (SEM). Both in-situ DLS and in-situ SEM reveal that the sizes of aggregated nanospheres increase with time until the formation of equilibrium H-aggregates...
October 20, 2016: Chemistry: a European Journal
Takahisa Miyatake, Tomoyuki Yokoi, Taro Fuchikawa, Nobuyoshi Korehisa, Toru Kamura, Kana Nanba, Shinsuke Ryouji, Nagisa Kamioka, Mantaro Hironaka, Midori Osada, Takahiko Hariyama, Rikiya Sasaki, Kazutaka Shinoda
The cigarette beetle, Lasioderma serricorne (F.), is an important stored-product pest worldwide because it damages dry foods. Detection and removal of the female L. serricorne will help to facilitate the control of the insect by removal of the egg-laying populations. In this manuscript, we examined the responses by L. serricorne to direct and reflected light in transparent cube (50 m(3)) set in a chamber (200 m(3)) and a stored facility with both direct and reflected UV-LED lights. The study also examined the responses by the beetles to light in the presence or absence of pheromone in traps that are placed at different heights...
October 19, 2016: Journal of Economic Entomology
Jedsada Sukantamala, Kong-Wah Sing, Narong Jaturas, Raxsina Polseela, John-James Wilson
Certain species of Phlebotomine sandflies (Diptera: Psychodidae) are vectors of the protozoa which causes leishmaniasis. Sandflies are found breeding in enclosed places like caves. Thailand is a popular tourist destination, including for ecotourism activities like caving, which increases the risk of contact between tourists and sandflies. Surveillance of sandflies is important for monitoring this risk but identification of species based on morphology is challenged by phenotypic plasticity and cryptic diversity...
October 19, 2016: Mitochondrial DNA. Part A. DNA Mapping, Sequencing, and Analysis
Anders Sandell, Davide Ragazzon, Andreas Schaefer, Mari Helene Farstad, Anne Borg
We present a dedicated synchrotron radiation photoelectron spectroscopy (SR-PES) study of a photochemical reaction on the surface of rutile TiO2(110). The photoreaction kinetics of carboxylate species (trimethyl acetate, TMA) upon irradiation by UV and soft x-rays were monitored and we show that it is possible to control the reaction rates from UV light and soft x-rays independently. We directly observe Ti4+ → Ti3+ conversion upon irradiation, attributed to electron trapping at Ti sites close to surface OH groups formed by deprotonation of the parent molecule, trimethyl acetic acid (TMAA)...
October 18, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Peng Zhang, Benhua Xu, Cunxu Gao, Guilin Chen, Meizhen Gao
Uniform Co9Se8 quantum dots (CSQDs) were successfully synthesized through a facile solvothermal method. The obtained CSQDs with average size of 3.2 ± 0.1 nm and thickness of 1.8 ± 0.2 nm were demonstrated good stability and strong fluorescence under UV light after being easily dispersed in both of N, N-dimethylformamide (DMF) and deionized water. We demonstrated the flexible resistive switching memory device based on the hybridization of CSQDs and polyvinylpyrrolidone (PVP) (CSQDs-PVP). The device with the Al/CSQDs-PVP/Pt/poly(ethylene terephthalate) (PET) structure represented excellent switching parameters such as high ON/OFF current ratio, low operating voltages, good stability and flexibility...
October 18, 2016: ACS Applied Materials & Interfaces
Qiang Hao, Xiuxiu Niu, Changshun Nie, Simeng Hao, Wei Zou, Jiangman Ge, Daimei Chen, Wenqing Yao
SiO2, an insulator, hardly has any photocatalytic acitivity due to its intrinsic property, and it is generally used as a hard template to increase the surface area of catalysts. However, in this work, we found that the surface state of the insulator SiO2 can promote the migration of photogenerated charge carriers, leading to the enhancement of the photooxidation ability of graphitic carbon nitride (g-C3N4). A one-pot calcination method was employed to prepare g-C3N4/SiO2 composites using melamine and SiO2 as precursors...
October 17, 2016: Physical Chemistry Chemical Physics: PCCP
Yoichiro Nakano, Takashi Yanase, Taro Nagahama, Hajime Yoshida, Toshihiro Shimada
The water vapor transmission rate (WVTR) of a gas barrier coating is a critically important parameter for flexible organic device packaging, but its accurate measurement without mechanical stress to ultrathin films has been a significant challenge in instrumental analysis. At the current stage, no reliable results have been reported in the range of 10(-6) g m(-2) day(-1) that is required for organic light emitting diodes (OLEDs). In this article, we describe a solution for this difficult, but important measurement, involving enhanced sensitivity by a cold trap, stabilized temperature system, pumped sealing and calibration by a standard conductance element...
October 17, 2016: Scientific Reports
Belén Sotillo, Vibhav Bharadwaj, J P Hadden, Masaaki Sakakura, Andrea Chiappini, Toney Teddy Fernandez, Stefano Longhi, Ottavia Jedrkiewicz, Yasuhiko Shimotsuma, Luigino Criante, Roberto Osellame, Gianluca Galzerano, Maurizio Ferrari, Kiyotaka Miura, Roberta Ramponi, Paul E Barclay, Shane Michael Eaton
Diamond is a promising platform for sensing and quantum processing owing to the remarkable properties of the nitrogen-vacancy (NV) impurity. The electrons of the NV center, largely localized at the vacancy site, combine to form a spin triplet, which can be polarized with 532 nm laser light, even at room temperature. The NV's states are isolated from environmental perturbations making their spin coherence comparable to trapped ions. An important breakthrough would be in connecting, using waveguides, multiple diamond NVs together optically...
October 17, 2016: Scientific Reports
Ximiao Hou, Michael C DeSantis, Chunjuan Tian, Wei Cheng
Although Ashkin and Dziedzic first demonstrated optical trapping of individual tobacco mosaic viruses in suspension as early as 1987, this pioneering work has not been followed up only until recently. Using human immunodeficiency virus type 1 (HIV-1) as a model virus, we have recently demonstrated that a single HIV-1 virion can be stabled trapped, manipulated and measured in physiological media with high precision. The capability to optically trap a single virion in suspension not only allows us to determine, for the first time, the refractive index of a single virus with high precision, but also quantitate the heterogeneity among individual virions with single-molecule resolution, the results of which shed light on the molecular mechanisms of virion infectivity...
August 2016: Proceedings of SPIE
G Meenakshi, A Sivasamy
Semiconductor zinc oxide nanorods (NRZnO) were prepared by sol-gel technique using zinc acetate as the precursor and ammonia as the precipitating agent. The prepared photocatalyst were characterized by X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV-Visible diffuse reflectance spectroscopy (UV-Vis-DRS), X-ray photoelectron spectroscopy (XPS), Field Emission-Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), High Resolution-Tunneling Microscope (HR-TEM), Brunauer, Emmett and Teller (BET) and electron paramagnetic resonance spectroscopy (EPR) analysis...
October 13, 2016: Ecotoxicology and Environmental Safety
Dong Jin Lee, G Mohan Kumar, P Ilanchezhiyan, Jae-Chul Lee, Sung Ryong Ryu, Tae Won Kang
Nowadays, solid-state inorganic-organic hybrid solar cells based on one-dimensional (1D) inorganic semiconducting nanostructures and organic polymers are believed to offer convincing solutions for the realm of next generation solar cells. In this regard, 1D ZnCdS nanowire (NW) arrays were fabricated on transparent conducting substrates through a catalyst free co-evaporation method and their wurtzite structural characteristics, 1D morphological layout and valence state/composition were studied in detail using X-ray diffraction, high-resolution electron microscopy and X-ray photoelectron spectroscopy, respectively...
October 5, 2016: Journal of Colloid and Interface Science
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