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# Optical

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#1
Xin Luo, Chi Fang, Caihua Wan, Jialin Cai, Yong Liu, Xiufeng Han, Zhihong Lu, Rui Xiong, Zhongming Zeng
This article reports the characterization of WTe<sub>2</sub> ultrathin flakes devices with characterization of magnetoresistance and Hall resistivity. We found that ultrathin flakes of WTe<sub>2</sub> do not exhibit magnetoresistance saturation when subject to high fields, in a manner similar to their bulk characteristic. The linearity of Hall resistivity in our devices could confirm the compensation of electrons and holes. By relating experimental results to a classic two-band model, we demonstrate that the lower magnetoresistance values may be caused by decreased carrier mobility in our samples...
January 19, 2017: Nanotechnology
#2
REVIEW
Jon Ashley, Mohammad-Ali Shahbazi, Krishna Kant, Vinayaka Aaydha Chidambara, Anders Wolff, Dang Duong Bang, Yi Sun
Molecularly imprinted polymers (MIPs) are biomimetics which can selectively bind to analytes of interest. One of the most interesting areas where MIPs have shown the biggest potential is food analysis. MIPs have found use as sorbents in sample preparation attributed to the high selectivity and high loading capacity. MIPs have been intensively employed in classical solid-phase extraction and solid-phase microextraction. More recently, MIPs have been combined with magnetic bead extraction, which greatly simplifies sample handling procedures...
January 11, 2017: Biosensors & Bioelectronics
#3
Pooja D, Sonia Saini, Anupma Thakur, Baban Kumar, Sachin Tyagi, Manoj K Nayak
Carbon quantum dots (CQDs) have emerged out as promising fluorescent probes for hazardous heavy metals detection in recent past. In this study, water soluble CQDs were synthesized by facile microwave pyrolysis of citric acid & cysteamine, and functionalized with ditheritheritol to impart thiol functionalities at surface for selective detection of toxic arsenite in water. Microscopic analysis reveals that the synthesized CQDs are of uniform size (diameter ∼5nm) and confirmed to have surface SH groups by FT-IR...
January 12, 2017: Journal of Hazardous Materials
#4
Bingqian Wang, Bangzhu Peng
This work aims to investigate the potential of fiber-optic Fourier transform-near-infrared (FT-NIR) spectrometry associated with chemometric analysis, which will be applied to monitor time-related changes in residual sugar and alcohol strength during kiwi wine fermentation. NIR calibration models for residual sugar and alcohol strength during kiwi wine fermentation were established on the FT-NIR spectra of 98 samples scanned in a fiber-optic FT-NIR spectrometer, and partial least squares regression method. The results showed that R(2) and root mean square error of cross-validation could achieve 0...
January 19, 2017: Journal of Food Science
#5
Cynara Carvalho Parente, Fernando S M Bezerra, Plutarco I Parente, Raimundo V Dias-Neto, Samanta C C Xavier, Alberto N Ramos, Filipe A Carvalho-Costa, Marli M Lima
BACKGROUND: The aim of this work was to explore the potential risk of vector-borne Chagas disease in urban districts in northeastern Brazil, by analyzing the spatiotemporal distributions and natural infection rates with Trypanosoma cruzi of triatomine species captured in recent years. The main motivation of this work was an acute human case of Chagas disease reported in 2008 in the municipality of Sobral. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed data from community-based entomological surveillance carried out from 2010 to 2014...
2017: PloS One
#6
Burghard Lipphardt, Vladislav Gerginov, Stefan Weyers
We describe an optical frequency stabilization scheme of a microwave oscillator that is used for the interrogation of primary caesium fountain clocks. Because of its superior phase noise properties, this scheme, which is based on an ultrastable laser and a femtosecond laser frequency comb, overcomes the frequency instability limitations of fountain clocks given by the previously utilized quartz-oscillator-based frequency synthesis. The presented scheme combines the transfer of the short-term frequency instability of an optical cavity and the long-term frequency instability of a hydrogen maser to the microwave oscillator and is designed to provide continuous long-term operation for extended measurement periods of several weeks...
January 5, 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
#7
Patrick D Barnett, Nirmal Lamsal, S Michael Angel
A spatial heterodyne spectrometer (SHS) is described for standoff laser-induced breakdown spectroscopy (LIBS) measurements. The spatial heterodyne LIBS spectrometer (SHLS) is a diffraction grating based interferometer with no moving parts that offers a very large field of view, high light throughput, and high spectral resolution in a small package. The field of view of the SHLS spectrometer is shown to be ∼1° in standoff LIBS measurements. In the SHLS system described here, the collection aperture was defined by the 10 mm diffraction gratings in the SHS and standoff LIBS measurements were made up to 20 m with no additional collection optics, corresponding to a collection solid angle of 0...
January 1, 2017: Applied Spectroscopy
#8
Damien Salomon, Agnès Messanvi, Joel Eymery, Gema Martínez-Criado
Noncentrosymmetric one dimensional structures are key driving forces behind advanced nanodevices. Owing to the critical role of silane injection in creating nanosized architectures, it has become a challenge to investigate the induced local lattice polarity in single GaN wires. Thus, if axial and radial structures are well-grown by a silane-mediated approach, an ideal model to study their polar orientations is formed. By combining synchrotron X-ray fluorescence and X-ray excited optical luminescence, we show here experimental evidence of the role of silane to promote the N-polarity, light emission and elemental incorporation within single wires...
January 19, 2017: Nano Letters
#9
Lixia Li, Dong Pan, Yongzhou Xue, Xiaolei Wang, Miaoling Lin, Dan Su, Qinglin Zhang, Xuezhe Yu, Hyok So, Dahai Wei, Baoquan Sun, PingHeng Tan, Anlian Pan, Jianhua Zhao
Here we report on the Ga self-catalyzed growth of near full-composition-range energy-gap-tunable GaAs1-xSbx nanowires by molecular-beam epitaxy. GaAs1-xSbx nanowires with different Sb content are systematically grown by tuning the Sb and As fluxes, and the As background. We find that GaAs1-xSbx nanowires with low Sb content can be grown directly on Si (111) substrates (0 ≤ x ≤ 0.60) and GaAs nanowire stems (0 ≤ x ≤ 0.50) by tuning the Sb and As fluxes. To obtain GaAs1-xSbx nanowires with x ranging from 0...
January 19, 2017: Nano Letters
#10
Yiyang Lin, E Thomas Pashuck, Michael R Thomas, Nadav Amdursky, Shih-Ting Wang, Lesley W Chow, Molly M Stevens
Supramolecular self-assembly is an important process that enables the conception of complex structures mimicking biological motifs. Herein, we constructed helical fibrils through chiral self-assembly of nucleobase-peptide conjugates (NPCs), where achiral nucleobases are helically displayed on the surface of fibrils, comparable to polymerized nucleic acids. Selective binding between DNA and the NPC fibrils was observed with fluorescence polarization. Taking advantage of metal-nucleobase recognition, we highlight the possibility of deposition/assembly of plasmonic nanoparticles onto the fibrillar constructs...
January 19, 2017: Angewandte Chemie
#11
Alexander M Grant, Brian J Lee, Chen-Ming Chang, Craig S Levin
PURPOSE: A brain sized radio frequency (RF)-penetrable PET insert has been designed for simultaneous operation with MRI systems. This system takes advantage of electro-optical coupling and battery power to electrically float the PET insert relative to the MRI ground, permitting RF signals to be transmitted through small gaps between the modules that form the PET ring. This design facilitates the use of the built-in body coil for RF transmission and thus could be inserted into any existing MR site wishing to achieve simultaneous PET/MR imaging...
January 2017: Medical Physics
#12
Han Gyu Kang, Ho-Young Lee, Kyeong Min Kim, Seong-Hyun Song, Gun Chul Hong, Seong Jong Hong
PURPOSE: The aim of this study is to integrate NIR, gamma, and visible imaging tools into a single endoscopic system to overcome the limitation of NIR using gamma imaging and to demonstrate the feasibility of endoscopic NIR/gamma/visible fusion imaging for sentinel lymph node (SLN) mapping with a small animal. METHODS: The endoscopic NIR/gamma/visible imaging system consists of a tungsten pinhole collimator, a plastic focusing lens, a BGO crystal (11 × 11 × 2 mm(3) ), a fiber-optic taper (front = 11 × 11 mm(2) , end = 4 × 4 mm(2) ), a 122-cm long endoscopic fiber bundle, an NIR emission filter, a relay lens, and a CCD camera...
January 2017: Medical Physics
#13
V S Shirure, S C George
Biocompatible polymers, such as polydimethylsiloxane (PDMS), are the materials of choice for creating organ-on-a-chip microfluidic platforms. Desirable qualities include ease of fabrication, optical clarity, and hydrophobicity, the latter of which facilitates oxygen transport to encased cells. An emerging and important application of organ-on-a-chip technology is drug discovery; however, a potential issue for polymer-based microfluidic devices has been highlighted by recent studies with PDMS, which have demonstrated absorption (and thus loss) of hydrophobic drugs into PDMS under certain experimental conditions...
January 19, 2017: Lab on a Chip
#14
Sarit Kipper, Ludmila Frolov, Ortal Guy, Michal Pellach, Yair Glick, Asaf Malichi, Binyamin A Knisbacher, Efrat Barbiro-Michaely, Dorit Avrahami, Yehuda Yavets-Chen, Erez Y Levanon, Doron Gerber
Integrated microfluidics is a sophisticated three-dimensional (multi layer) solution for high complexity serial or parallel processes. Fabrication of integrated microfluidic devices requires soft lithography and the stacking of thin-patterned PDMS layers. Precise layer alignment and bonding is crucial. There are no previously reported standards for alignment of the layers, which is mostly performed using uncontrolled processes with very low alignment success. As a result, integrated microfluidics is mostly used in academia rather than in the many potential industrial applications...
January 19, 2017: Lab on a Chip
#15
Kyungtaek Min, Muhammad Umar, Shinyoung Ryu, Soonil Lee, Sunghwan Kim
Ultra-thin and ultra-smooth gold (Au) films are appealing for photonic applications including surface plasmon resonances and transparent contacts. However, poor adhesion at the Au���dielectric interface prohibits the formation of a mechanically stable, ultra-thin, and ultra-smooth Au film. A conventional solution is to use a metallic adhesion layer, such as titanium and chromium however, such layers cause the optical properties of pure Au to deteriorate. Here we report the use of silk protein to enhance the adhesion at the Au���dielectric interfaces, thus obtaining ultra-smooth sub-10 nm Au films...
January 19, 2017: Nanotechnology
#16
Shimin Cao, Jiaojiao Zhou, Xuan Wei, Shu-Guang Cheng
Massless charge carriers in gate potential modulate graphene quantum well transport in a same way that electromagnetic wave propagates in optical fibers. Recent experiment by Kim {\it et al} (Nat. Phys. 12 1022) reports the valley symmetry preserved transport in graphene carrier guider. Based on a tight-binding model, the valley resolved transport coefficients are calculated with the method of scattering matrix theory. For a straight potential well, valley resolved conductance is quantized with value $2n+1$ multiply $2e^2/h$ with integer $n$...
January 19, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
#17
Alessandro DI Giorgio, Francesco Costa, Vittorio Virga, Francesco Saporito
April 2017: Minerva Cardioangiologica
#18
Jacek Bil, Maik J Grundeken, Tomasz Pawłowski, Robert J Gil
April 2017: Minerva Cardioangiologica
#19
REVIEW
Yu Huang, Wenbo Li, Meng Qin, Haihua Zhou, Xingye Zhang, Fengyu Li, Yanlin Song
With facile manufacturability and modifiability, impressive nanoparticles (NPs) assembly applications were performed for functional patterned devices, which have attracted booming research attention due to their increasing applications in high-performance optical/electrical devices for sensing, electronics, displays, and catalysis. By virtue of easy and direct fabrication to desired patterns, high throughput, and low cost, NPs assembly printing is one of the most promising candidates for the manufacturing of functional micro-chips...
January 2017: Small
#20
Zhou-Hao Zhu, Meng-Lin Chen, Guo-Fang Jiang
An efficient access to optically active sulfahydantoins, 4-aryl-1,2,5-thiadiazolidin-3-one 1,1-dioxides, was developed through palladium-catalyzed asymmetric hydrogenation of the corresponding cyclic N-sulfonylketimines with up to 98% ee.
January 19, 2017: Organic & Biomolecular Chemistry
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