WorldWideScience

Sample records for high capability raman

  1. Raman Spectroscopy at High Pressures

    Directory of Open Access Journals (Sweden)

    Alexander F. Goncharov

    2012-01-01

    Full Text Available Raman spectroscopy is one of the most informative probes for studies of material properties under extreme conditions of high pressure. The Raman techniques have become more versatile over the last decades as a new generation of optical filters and multichannel detectors become available. Here, recent progress in the Raman techniques for high-pressure research and its applications in numerous scientific disciplines including physics and chemistry of materials under extremes, earth and planetary science, new materials synthesis, and high-pressure metrology will be discussed.

  2. Capability of Raman lidar for monitoring the variation of atmospheric CO2 profile

    Institute of Scientific and Technical Information of China (English)

    Zhao Pei-Tao; Zhang Yin-Chao; Wang Lian; Hu Shun-Xing; Su Jia; Cao Kai-Fa; Zhao Yue-Feng; Hu Huan-Ling

    2008-01-01

    Lidar (Light detection and ranging) has special capabilities for remote sensing of many different behaviours of the atmosphere.One of the techniques which show a great deal of promise for several applications is Raman scattering.The detecting capability,including maximum operation range and minimum detectable gas concentration is one of the most significant parameters for lidar remote sensing of pollutants.In this paper,based on the new method for evaluating the capabilities of a Raman lidar system,we present an evaluation of detecting capability of Raman lidar for monitoring atmospheric CO2 in Hefei.Numerical simulations about the influence of atmospheric conditions on lidar detecting capability were carried out,and a conclusion can be drawn that the maximum difference of the operation ranges caused by the weather conditions alone can reach about 0.4 to 0.5kin with a measuring precision within 30ppmv.The range of minimum detectable concentration caused by the weather conditions alone can reach about 20 to 35 ppmv in vertical direction for 20000 shots at a distance of 1 km on the assumption that other parameters are kept constant.The other corresponding parameters under different conditions are also given.The capability of Raman lidar operated in vertical direction was found to be superior to that operated in horizontal direction.During practical measurement with the Raman lidar whose hardware components were fixed,aerosol scattering extinction effect would be a significant factor that influenced the capability of Raman lidar.This work may be a valuable reference for lidar system designing,measurement accuracy improving and data processing.

  3. High pressure Raman scattering of silicon nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Khachadorian, Sevak; Scheel, Harald; Thomsen, Christian [Institut fuer Festkoerperphysik, Technische Universitaet Berlin, 10623 Berlin (Germany); Papagelis, Konstantinos [Materials Science Department, University of Patras, 26504 Patras (Greece); Colli, Alan [Nokia Research Centre, 21 J J Thomson Avenue, Cambridge CB3 0FA (United Kingdom); Ferrari, Andrea C, E-mail: khachadorian@physik.tu-berlin.de [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)

    2011-05-13

    We study the high pressure response, up to 8 GPa, of silicon nanowires (SiNWs) with {approx} 15 nm diameter, by Raman spectroscopy. The first order Raman peak shows a superlinear trend, more pronounced compared to bulk Si. Combining transmission electron microscopy and Raman measurements we estimate the SiNWs' bulk modulus and the Grueneisen parameters. We detect an increase of Raman linewidth at {approx} 4 GPa, and assign it to pressure induced activation of a decay process into LO and TA phonons. This pressure is smaller compared to the {approx} 7 GPa reported for bulk Si. We do not observe evidence of phase transitions, such as discontinuities or change in the pressure slopes, in the investigated pressure range.

  4. Stimulated Raman backscattering at high laser intensities

    Energy Technology Data Exchange (ETDEWEB)

    Skoric, M.M. [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Tajima, Toshiki; Sasaki, Akira; Maluckov, A.; Jovanovic, M.

    1998-03-01

    Signatures of Stimulated Raman backscattering of a short-pulse high-intensity laser interacting with an underdense plasma are discussed. We introduce a nonlinear three-wave interaction model that accounts for laser pump depletion and relativistic detuning. A mechanism is revealed based on a generic route to chaos, that predicts a progressive increase of the backscatter complexity with a growing laser intensity. Importance of kinetic effects is outlined and demonstrated in fluid-hybrid and particle simulations. As an application, we show that spectral anomalies of the backscatter, predicted by the above model, are consistent with recent sub-picosecond, high-intensity laser gas-target measurements at Livermore and elsewhere. Finally, a recently proposed scheme for generation of ultra-short, low-prepulse laser pulses by Raman backscattering in a thin foil target, is shown. (author)

  5. High-pressure Raman study of Terephthalonitrile

    Science.gov (United States)

    Li, DongFei; Zhang, KeWei; Song, MingXing; Zhai, NaiCui; Sun, ChengLin; Li, HaiBo

    2017-02-01

    The in situ high-pressure Raman spectra of Terephthalonitrile (TPN) have been investigated from ambient to 12.6 GPa at room temperature. All the fundamental vibrational modes of TPN at ambient were assigned based on the first-principle calculations. A detailed Raman spectroscopy analysis revealed that TPN underwent a phase transition at 5.3 GPa. The frequencies of the TPN Raman peaks increase with increasing the pressure which can be attributed to the reduction in the interatomic distances and the escalation of effective force constants. The intensity of the C-C-C ring-out-plane deformation mode increases gradually as the frequency remains almost constant during the compression which can be explained by the existence of π-π interactions in TPN molecules. Additionally, the pressure-induced structural changes of TPN on the Fermi resonance between the C ≡ N out-of-plane vibration mode and the C - CN out-of-plane vibration mode have been analyzed.

  6. Ultraviolet Raman lidar for high-accuracy profiling of aerosol extinction coefficient

    Institute of Scientific and Technical Information of China (English)

    Fei Gao; Xiaoquan Song; Yufeng Wang; Yi Zhou; Dengxin Hua

    2009-01-01

    An ultraviolet (UV) Raman lidar system at 354.7 nm has been developed for accurately measuring the aerosol extinction profiles. A spectroscopic filter combining a high-spectral-resolution grating with two narrowband mirrors is used to separate the vibrational Raman scattering signal of N2 at a central wave-length of 386.7 nm and the elastic scattering signal at 354.7 nm. The aerosol extinction is derived from the Raman scattering of N2 and the elastic scattering by the use of Raman method and Klett method, respectively. The derived results of aerosol extinction are used to compare the difference of two retrieval methods, and the preliminary experiment shows that the Raman lidar system operated in analog detection mode has the capability of measuring aerosol profiles up to a height of 3 km with a laser energy of 250 mJ and an integration time of 8 min.

  7. The development of a wide-field, high-resolution UV Raman hyperspectral imager

    Science.gov (United States)

    Gomer, Nathaniel R.; Nelson, Matthew P.; Angel, S. M.

    2015-05-01

    Raman spectroscopy is a valuable tool for the investigation and analysis of explosive and biological analytes because it provides a unique molecular fingerprint that allows for unambiguous target identification. Raman can be advantageous when utilized with deep UV excitation, but typical deep UV Raman systems have numerous limitations that hinder their performance and make their potential integration onto a field portable platform difficult. These systems typically offer very low throughput, are physically large and heavy, and can only probe an area the size of a tightly focused laser, severely diminishing the ability of the system to investigate large areas efficiently. The majority of these limitations are directly related to a system's spectrometer, which is typically dispersive grating based and requires a very narrow slit width and long focal length optics to achieve high spectral resolution. To address these shortcomings, ChemImage Sensor Systems (CISS), teaming with the University of South Carolina, are developing a revolutionary wide-field Raman hyperspectral imaging system capable of providing wide-area, high resolution measurements with greatly increased throughput in a small form factor, which would revolutionize the way Raman is conducted and applied. The innovation couples a spatial heterodyne spectrometer (SHS), a novel slit-less spectrometer that operates similar to Michelson interferometer, with a fiber array spectral translator (FAST) fiber array, a two-dimensional imaging fiber for hyperspectral imagery. This combination of technologies creates a novel wide-field, high throughput Raman hyperspectral imager capable of yielding very high spectral resolution measurements using defocused excitation, giving the system a greater area coverage and faster search rate than traditional Raman systems. This paper will focus on the need for an innovative UV Raman system, provide an overview of spatial heterodyne Raman spectroscopy, and discuss the development

  8. Preventing Raman Lasing in High-Q WGM Resonators

    Science.gov (United States)

    Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry; Maleki, Lute

    2007-01-01

    A generic design has been conceived to suppress the Raman effect in whispering- gallery-mode (WGM) optical resonators that have high values of the resonance quality factor (Q). Although it is possible to exploit the Raman effect (even striving to maximize the Raman gain to obtain Raman lasing), the present innovation is intended to satisfy a need that arises in applications in which the Raman effect inhibits the realization of the full potential of WGM resonators as frequency-selection components. Heretofore, in such applications, it has been necessary to operate high-Q WGM resonators at unattractively low power levels to prevent Raman lasing. (The Raman-lasing thresholds of WGM optical resonators are very low and are approximately proportional to Q(sup -2)). Heretofore, two ways of preventing Raman lasting at high power levels have been known, but both entail significant disadvantages: A resonator can be designed so that the optical field is spread over a relatively large mode volume to bring the power density below the threshold. For any given combination of Q and power level, there is certain mode volume wherein Raman lasing does not start. Unfortunately, a resonator that has a large mode volume also has a high spectral density, which is undesirable in a typical photonic application. A resonator can be cooled to the temperature of liquid helium, where the Raman spectrum is narrower and, therefore, the Raman gain is lower. However, liquid-helium cooling is inconvenient. The present design overcomes these disadvantages, making it possible to operate a low-spectral-density (even a single-mode) WGM resonator at a relatively high power level at room temperature, without risk of Raman lasing.

  9. High resolution full-spectrum water Raman lidar

    Institute of Scientific and Technical Information of China (English)

    LIU FuChao; YI Fan; JIA JingYu; ZHANG YunPeng; ZHANG ShaoDong; YU ChangMing; TAN Ying

    2012-01-01

    Knowledge of the temporal-spatial distribution of water content in atmosphere and water phase change in cloud is important for atmospheric study.For this purpose,we have developed a high resolution full-spectrum water Raman lidar that can collect Raman signals from ice,water droplets and water vapor simultaneously.A double-grating polychromator and a 32-channel photomultiplier-tube detector are used to obtain a spectral resolution of ~0.19 nm in the full Raman spectrum range of water.Preliminary observations present the water Raman spectrum characteristics of both the mixed-phase cloud and humid air under cloudless condition.

  10. High Power Photonic Crystal Fibre Raman Laser

    Institute of Scientific and Technical Information of China (English)

    YAN Pei-Guang; RUAN Shuang-Chen; YU Yong-Qin; GUO Chun-Yu; GUO Yuan; LIU Cheng-Xiang

    2006-01-01

    A cw Raman laser based on a 100-m photonic crystal fibre is demonstrated with up to 3.8 W output power at the incident pump power of 12 W, corresponding to an optical-to-optical efficiency of about 31.6%. The second order Stokes light, which is firstly reported in a cw photonic crystal fibre Raman laser, is obtained at 1183nm with an output power of 1.6 W and a slope efficiency of about 45.7%.

  11. New capability for hazardous materials ID within sealed containers using a portable spatially offset Raman spectroscopy (SORS) device

    Science.gov (United States)

    Stokes, Robert J.; Bailey, Mike; Bonthron, Stuart; Stone, Thomas; Maskall, Guy; Presly, Oliver; Roy, Eric; Tombling, Craig; Loeffen, Paul W.

    2016-10-01

    Raman spectroscopy allows the acquisition of molecularly specific signatures of pure compounds and mixtures making it a popular method for material identification applications. In hazardous materials, security and counter terrorism applications, conventional handheld Raman systems are typically limited to operation by line-of-sight or through relatively transparent plastic bags / clear glass vials. If materials are concealed behind thicker, coloured or opaque barriers it can be necessary to open and take a sample. Spatially Offset Raman Spectroscopy (SORS)[1] is a novel variant of Raman spectroscopy whereby multiple measurements at differing positions are used to separate the spectrum arising from the sub layers of a sample from the spectrum at the surface. For the first time, a handheld system based on SORS has been developed and applied to hazardous materials identification. The system - "Resolve" - enables new capabilities in the rapid identification of materials concealed by a wide variety of non-metallic sealed containers such as; coloured and opaque plastics, paper, card, sacks, fabric and glass. The range of potential target materials includes toxic industrial chemicals, explosives, narcotics, chemical warfare agents and biological materials. Resolve has the potential to improve the safety, efficiency and critical decision making in incident management, search operations, policing and ports and border operations. The operator is able to obtain a positive identification of a potentially hazardous material without opening or disturbing the container - to gain access to take a sample - thus improving safety. The technique is fast and simple thus suit and breathing gear time is used more efficiently. SORS also allows Raman to be deployed at an earlier stage in an event before more intrusive techniques are used. Evidential information is preserved and the chain of custody protected. Examples of detection capability for a number of materials and barrier types are

  12. Turbine vane with high temperature capable skins

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, Jay A [Oviedo, FL

    2012-07-10

    A turbine vane assembly includes an airfoil extending between an inner shroud and an outer shroud. The airfoil can include a substructure having an outer peripheral surface. At least a portion of the outer peripheral surface is covered by an external skin. The external skin can be made of a high temperature capable material, such as oxide dispersion strengthened alloys, intermetallic alloys, ceramic matrix composites or refractory alloys. The external skin can be formed, and the airfoil can be subsequently bi-cast around or onto the skin. The skin and the substructure can be attached by a plurality of attachment members extending between the skin and the substructure. The skin can be spaced from the outer peripheral surface of the substructure such that a cavity is formed therebetween. Coolant can be supplied to the cavity. Skins can also be applied to the gas path faces of the inner and outer shrouds.

  13. Highly birefringent crystal for Raman transitions with phase modulators

    Science.gov (United States)

    Arias, Nieves; Abediyeh, Vahide; Hamzeloui, Saeed; Jeronimo-Moreno, Yasser; Gomez, Eduardo

    2016-05-01

    We present a system to excite Raman transitions with minimum phase noise. The system uses a phase modulator to generate the phase locked beams required for the transition. We use a long calcite crystal to filter out one of the sidebands, avoiding the cancellation that appears at high detunings for phase modulation. The measured phase noise is limited by the quality of the microwave synthesizer. We use the calcite crystal a second time to produce a co-propagating Raman pair with perpendicular polarizations to drive velocity insensitive Raman transitions. Support from CONACYT and Fundacion Marcos Moshinsky.

  14. Narrow-band, narrow-field-of-view Raman lidar with combined day and night capability for tropospheric water-vapor profile measurements.

    Science.gov (United States)

    Bisson, S E; Goldsmith, J E; Mitchell, M G

    1999-03-20

    We describe a high-performance Raman lidar system with combined day and night capability for tropospheric water-vapor profile measurements. The system incorporates high-performance UV interference filters and a narrow-band, dual-field-of-view receiver for rejection of background sunlight. Daytime performance has been demonstrated up to 5 km with 150-m vertical and 5-min temporal averaging. The nighttime performance is significantly better with measurements routinely extending from 10 to 12 km with 75-m range resolution and a 5-min temporal average. We describe design issues for daytime operation and a novel daytime calibration technique.

  15. High-Rate Capable Floating Strip Micromegas

    CERN Document Server

    Bortfeldt, Jonathan; Biebel, Otmar; Danger, Helge; Flierl, Bernhard; Hertenberger, Ralf; Lösel, Philipp; Moll, Samuel; Parodi, Katia; Rinaldi, Ilaria; Ruschke, Alexander; Zibell, André

    2015-01-01

    We report on the optimization of discharge insensitive floating strip Micromegas (MICRO-MEsh GASeous) detectors, fit for use in high-energy muon spectrometers. The suitability of these detectors for particle tracking is shown in high-background environments and at very high particle fluxes up to 60MHz/cm$^2$. Measurement and simulation of the microscopic discharge behavior have demonstrated the excellent discharge tolerance. A floating strip Micromegas with an active area of 48cm$\\times$50cm with 1920 copper anode strips exhibits in 120GeV pion beams a spatial resolution of 50$\\mu$m at detection efficiencies above 95%. Pulse height, spatial resolution and detection efficiency are homogeneous over the detector. Reconstruction of particle track inclination in a single detector plane is discussed, optimum angular resolutions below $5^\\circ$ are observed. Systematic deviations of this $\\mu$TPC-method are fully understood. The reconstruction capabilities for minimum ionizing muons are investigated in a 6.4cm$\\time...

  16. Quantitative polarized Raman spectroscopy in highly turbid bone tissue

    Science.gov (United States)

    Raghavan, Mekhala; Sahar, Nadder D.; Wilson, Robert H.; Mycek, Mary-Ann; Pleshko, Nancy; Kohn, David H.; Morris, Michael D.

    2010-05-01

    Polarized Raman spectroscopy allows measurement of molecular orientation and composition and is widely used in the study of polymer systems. Here, we extend the technique to the extraction of quantitative orientation information from bone tissue, which is optically thick and highly turbid. We discuss multiple scattering effects in tissue and show that repeated measurements using a series of objectives of differing numerical apertures can be employed to assess the contributions of sample turbidity and depth of field on polarized Raman measurements. A high numerical aperture objective minimizes the systematic errors introduced by multiple scattering. We test and validate the use of polarized Raman spectroscopy using wild-type and genetically modified (oim/oim model of osteogenesis imperfecta) murine bones. Mineral orientation distribution functions show that mineral crystallites are not as well aligned (p0.05). We provide evidence that simultaneous quantitative measurements of mineral and collagen orientations on intact bone specimens are possible using polarized Raman spectroscopy.

  17. High-Speed Coherent Raman Fingerprint Imaging of Biological Tissues

    CERN Document Server

    Camp, Charles H; Heddleston, John M; Hartshorn, Christopher M; Walker, Angela R Hight; Rich, Jeremy N; Lathia, Justin D; Cicerone, Marcus T

    2014-01-01

    We have developed a coherent Raman imaging platform using broadband coherent anti-Stokes Raman scattering (BCARS) that provides an unprecedented combination of speed, sensitivity, and spectral breadth. The system utilizes a unique configuration of laser sources that probes the Raman spectrum over 3,000 cm$^{-1}$ and generates an especially strong response in the typically weak Raman "fingerprint" region through heterodyne amplification of the anti-Stokes photons with a large nonresonant background (NRB) while maintaining high spectral resolution of $<$ 13 cm$^{-1}$. For histology and pathology, this system shows promise in highlighting major tissue components in a non-destructive, label-free manner. We demonstrate high-speed chemical imaging in two- and three-dimensional views of healthy murine liver and pancreas tissues and interfaces between xenograft brain tumors and the surrounding healthy brain matter.

  18. Towards high-throughput microfluidic Raman-activated cell sorting.

    Science.gov (United States)

    Zhang, Qiang; Zhang, Peiran; Gou, Honglei; Mou, Chunbo; Huang, Wei E; Yang, Menglong; Xu, Jian; Ma, Bo

    2015-09-21

    Raman-activated cell sorting (RACS) is a promising single-cell analysis technology that is able to identify and isolate individual cells of targeted type, state or environment from an isogenic population or complex consortium of cells, in a label-free and non-invasive manner. However, compared with those widely used yet labeling-required or staining-dependent cell sorting technologies such as FACS and MACS, the weak Raman signal greatly limits the further development of the existing RACS systems to achieve higher throughput. Strategies that can tackle this bottleneck include, first, improvement of Raman-acquisition efficiency and quality based on advanced Raman spectrometers and enhanced Raman techniques; second, development of novel microfluidic devices for cell sorting followed by integration into a complete RACS system. Exploiting these strategies, prototypes for a new generation of RACS have been demonstrated, such as flow-based OT-RACS, DEP-RACS, and SERS/CARS flow cytometry. Such high-throughput microfluidic RACS can provide biologists with a powerful single-cell analysis tool to explore the scientific questions or applications that have been beyond the reach of FACS and MACS.

  19. Raman spectroscopic studies on p-terphenyl under high pressure

    Science.gov (United States)

    Liu, Tianyuan; Xu, Shengnan; Sun, Chenglin; Zhou, Mi

    2014-11-01

    High-pressure Raman scattering studies are performed on p-terphenyl up to 5 GPa. The Raman activities of different symmetric molecules were analyzed by means of group theory methods. A phase transition was detected at 1.3 GPa from changes in the slope on plots of frequency versus pressure. The diminishing of internal modes indicated that the molecule symmetry transformed from C2 to D2h. This is an effective method for detecting planar molecular structure of p-terphenyl by ring-ring stretching vibration mode, which can provide a new spectroscopic evidence of planar conjugated polyphenyl molecular conformation.

  20. High-pressure Raman spectroscopy of carbon onions and nanocapsules

    Science.gov (United States)

    Guo, J. J.; Liu, G. H.; Wang, X. M.; Fujita, T.; Xu, B. S.; Chen, M. W.

    2009-08-01

    We report high-pressure Raman spectra of carbon onions and nanocapsules investigated by diamond anvil cell experiments. The pressure coefficient and elastic behavior of carbon onions and nanocapsules are found to be very similar to those of multiwall carbon nanotubes. Additionally, detectable structure changes, particularly the collapse of the concentric graphite structure, cannot been seen at pressures as high as ˜20 GPa, demonstrating that carbon onions and nanocapsules have significant hardness and can sustain very high pressures.

  1. Development of high temperature capable piezoelectric sensors

    Science.gov (United States)

    Suprock, Andrew D.; Tittmann, Bernhard R.

    2017-02-01

    The objective of the project was to investigate the influence of the temperature effect on ultrasonic transducers based on a comparison of the effects of high temperature conditions versus those of high temperature and irradiation on the transducer system. There was also a preliminary move towards the establishment of the means for optimizing the bulk single crystal transducer fabrication process in order to achieve peak efficiency and maximum effectiveness in both irradiated and non-irradiated high temperature applications. Optimization of the material components within the transducer will greatly increase non-destructive testing abilities for industry, structural health monitoring. Here is presented a progress report on the testing of several different piezoelectric materials under high temperature conditions. The viability of aluminum nitride (AlN) as a transducer material in high temperature conditions has been previously explored [1] and has been further tested to ensure reliability. Bistmuth Titanate (BiT) has also been tested and has displayed excellent effectiveness for high temperature application.

  2. A high-throughput Raman notch filter set

    Science.gov (United States)

    Puppels, G. J.; Huizinga, A.; Krabbe, H. W.; de Boer, H. A.; Gijsbers, G.; de Mul, F. F. M.

    1990-12-01

    A chevron-type Raman notch filter (RNF) set is described. lt combines a high signal throughput (up to 90% around 1600 cm-1 and ≳80% between and 700 and 2700 cm-1) with a laser line suppression of 108-109. The filter set can be used to replace the first two dispersion stages in triple-stage Raman monochromators commonly employed in multichannel detection systems. This yields a gain in intensity of the detected Raman signal of a factor of 4. It is shown that in Raman spectrometers with a backscatter geometry, the filter set can also be used to optically couple the microscope and the spectrometer. This leads to a further increase in signal intensity of a factor of 3-4 as compared to the situation where a beam splitter is used. Additional advantages of the RNF set are the fact that signal throughput is almost polarization independent over a large spectral interval and that it offers the possibility to simultaneously record Stokes and anti-Stokes spectra.

  3. High precision stress measurements in semiconductor structures by Raman microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Uhlig, Benjamin

    2009-07-01

    Stress in silicon structures plays an essential role in modern semiconductor technology. This stress has to be measured and due to the ongoing miniaturization in today's semiconductor industry, the measuring method has to meet certain requirements. The present thesis deals with the question how Raman spectroscopy can be used to measure the state of stress in semiconductor structures. In the first chapter the relation between Raman peakshift and stress in the material is explained. It is shown that detailed stress maps with a spatial resolution close to the diffraction limit can be obtained in structured semiconductor samples. Furthermore a novel procedure, the so called Stokes-AntiStokes-Difference method is introduced. With this method, topography, tool or drift effects can be distinguished from stress related influences in the sample. In the next chapter Tip-enhanced Raman Scattering (TERS) and its application for an improvement in lateral resolution is discussed. For this, a study is presented, which shows the influence of metal particles on the intensity and localization of the Raman signal. A method to attach metal particles to scannable tips is successfully applied. First TERS scans are shown and their impact on and challenges for high resolution stress measurements on semiconductor structures is explained. (orig.)

  4. Raman spectroscopy on carbon nanotubes at high pressure

    OpenAIRE

    Loa, I.

    2003-01-01

    Raman spectroscopy has been the most extensively employed method to study carbon nanotubes at high pressures. This review covers reversible pressure-induced changes of the lattice dynamics and structure of single- and multi-wall carbon nanotubes as well as irreversible transformations induced by high pressures. The interplay of covalent and van-der-Waals bonding in single-wall nanotube bundles and a structural distortion near 2 GPa are discussed in detail. Attempts of transforming carbon nano...

  5. Simultaneous fingerprint and high-wavenumber fiber-optic Raman spectroscopy enhances real-time in vivo diagnosis of adenomatous polyps during colonoscopy.

    Science.gov (United States)

    Bergholt, Mads Sylvest; Lin, Kan; Wang, Jianfeng; Zheng, Wei; Xu, Hongzhi; Huang, Qingwen; Ren, Jian-Lin; Ho, Khek Yu; Teh, Ming; Srivastava, Supriya; Wong, Benjamin; Yeoh, Khay Guan; Huang, Zhiwei

    2016-04-01

    Colorectal cancer can be prevented if detected early (e.g., precancerous polyps-adenoma). Endoscopic differential diagnosis of hyperplastic polyps (that have little or no risk of malignant transformation) and adenomas (that have prominent malignant latency) remains an unambiguous clinical challenge. Raman spectroscopy is an optical vibrational technique capable of probing biomolecular changes of tissue associated with neoplastic transformation. This work aims to apply a fiber-optic simultaneous fingerprint (FP) and high wavenumber (HW) Raman spectroscopy technique for real-time in vivo assessment of adenomatous polyps during clinical colonoscopy. We have developed a fiber-optic Raman endoscopic technique capable of simultaneously acquiring both the FP (i.e., 800-1800 cm(-1)) and HW (i.e., 2800-3600 cm(-1)) Raman spectra from colorectal tissue subsurface (Raman spectra were acquired from 50 patients with 17 colorectal polyps during clinical colonoscopy. Prominent Raman spectral differences (p Raman endoscopy provides a diagnostic sensitivity of 90.9% and specificity of 83.3% for differentiating adenoma from hyperplastic polyps, which is superior to either the FP or HW Raman technique alone. This study shows that simultaneous FP/HW Raman spectroscopy technique has the potential to be a clinically powerful tool for improving early diagnosis of adenomatous polyps in vivo during colonoscopic examination. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. High directivity optical antenna substrates for surface enhanced Raman scattering.

    Science.gov (United States)

    Wang, Dongxing; Zhu, Wenqi; Chu, Yizhuo; Crozier, Kenneth B

    2012-08-22

    A two-dimensional array of gold optical antennas integrated with a one-dimensional array of gold strips and mirrors is introduced and fabricated. The experimental results show that this design achieves average surface-enhanced Raman scattering (SERS) enhancement factors as high as 1.2 × 10(10) , which is more than two orders of magnitude larger than optical antennas without the gold strips and gold mirror.

  7. A Novel Technique for Raman Analysis of Highly Radioactive Samples Using Any Standard Micro-Raman Spectrometer.

    Science.gov (United States)

    Colle, Jean-Yves; Naji, Mohamed; Sierig, Mark; Manara, Dario

    2017-04-12

    A novel approach for the Raman measurement of nuclear materials is reported in this paper. It consists of the enclosure of the radioactive sample in a tight capsule that isolates the material from the atmosphere. The capsule can optionally be filled with a chosen gas pressurized up to 20 bars. The micro-Raman measurement is performed through an optical-grade quartz window. This technique permits accurate Raman measurements with no need for the spectrometer to be enclosed in an alpha-tight containment. It therefore allows the use of all options of the Raman spectrometer, like multi-wavelength laser excitation, different polarizations, and single or triple spectrometer modes. Some examples of measurements are shown and discussed. First, some spectral features of a highly radioactive americium oxide sample (AmO2) are presented. Then, we report the Raman spectra of neptunium oxide (NpO2) samples, the interpretation of which is greatly improved by employing three different excitation wavelengths, (17)O doping, and a triple mode configuration to measure the anti-stokes Raman lines. This last feature also allows the estimation of the sample surface temperature. Finally, data that were measured on a sample from Chernobyl lava, where phases are identified by Raman mapping, are shown.

  8. Preparations for the Launch of the EXOMARS Raman Laser Spectrometer — A Review of Recent Studies Which Highlight the Astrobiological and Geological Capabilities of Portable Raman Instrumentation

    Science.gov (United States)

    Hutchinson, I. B.; Edwards, H. G. M.; Ingley, R.; Harris, L.; McHugh, M.; Malherbe, C.; Jehlicka, J.; Marshall, C.; Parnell, J.

    2014-06-01

    A review of experiments performed on natural and analogue samples with prototype/portable instrumentation in preparation for the launch of the Raman Laser Spectrometer instrument on the ExoMars rover.

  9. High-pressure study of tetramethylsilane by Raman spectroscopy.

    Science.gov (United States)

    Qin, Zhen-Xing; Zhang, Jian-Bo; Troyan, Ivan; Palasyuk, Taras; Eremets, Mikhail; Chen, Xiao-Jia

    2012-01-14

    High-pressure behavior of tetramethylsilane, one of the Group IVa hydrides, was investigated by Raman scattering measurements at pressures up to 142 GPa and room temperature. Our results revealed the phase transitions at 0.6, 9, and 16 GPa from both the mode frequency shifts with pressure and the changes of the full width half maxima of these modes. These transitions were suggested to result from the changes in the inter- and intra-molecular bonding of this material. We also observed two other possible phase transitions at 49-69 GPa and 96 GPa. No indication of metallization in tetramethylsilane was found with stepwise compression to 142 GPa.

  10. High-power picosecond fiber source for coherent Raman microscopy.

    Science.gov (United States)

    Kieu, Khanh; Saar, Brian G; Holtom, Gary R; Xie, X Sunney; Wise, Frank W

    2009-07-01

    We report a high-power picosecond fiber pump laser system for coherent Raman microscopy (CRM). The fiber laser system generates 3.5 ps pulses with 6 W average power at 1030 nm. Frequency doubling yields more than 2 W of green light, which can be used to pump an optical parametric oscillator to produce the pump and the Stokes beams for CRM. Detailed performance data on the laser and the various wavelength conversion steps are discussed, together with representative CRM images of fresh animal tissue obtained with the new source.

  11. High-power picosecond fiber source for coherent Raman microscopy

    OpenAIRE

    Kieu, Khanh; Saar, Brian G.; Holtom, Gary R.; Xie, Xiaoliang Sunney; Wise, Frank W

    2009-01-01

    We report a high-power picosecond fiber pump laser system for coherent Raman microscopy (CRM). The fiber laser system generates 3.5 ps pulses with 6 W average power at 1030 nm. Frequency doubling yields more than 2 W of green light, which can be used to pump an optical parametric oscillator to produce the pump and the Stokes beams for CRM. Detailed performance data on the laser and the various wavelength conversion steps are discussed, together with representative CRM images of fresh animal t...

  12. {alpha}-Glycine under high pressures: a Raman scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Murli, Chitra; Sharma, S.M.Surinder M.; Karmakar, S.; Sikka, S.K

    2003-11-01

    High-pressure behaviour of {alpha}-glycine has been investigated up to {approx}23 GPa using Raman scattering technique. The experimental results show slope change in the CO{sub 2} bending, NH{sub 3} torsional and NH{sub 3} rocking modes around 3 GPa and are interpreted in terms of change in the nature of an N-H...O-C intra-layer hydrogen bond at this pressure. Several other spectral features seem to arise from pressure-induced variations in the inter-molecular coupling.

  13. Simultaneous fingerprint and high-wavenumber fiber-optic Raman spectroscopy improves in vivo diagnosis of esophageal squamous cell carcinoma at endoscopy

    Science.gov (United States)

    Wang, Jianfeng; Lin, Kan; Zheng, Wei; Yu Ho, Khek; Teh, Ming; Guan Yeoh, Khay; Huang, Zhiwei

    2015-01-01

    This work aims to evaluate clinical value of a fiber-optic Raman spectroscopy technique developed for in vivo diagnosis of esophageal squamous cell carcinoma (ESCC) during clinical endoscopy. We have developed a rapid fiber-optic Raman endoscopic system capable of simultaneously acquiring both fingerprint (FP)(800–1800 cm−1) and high-wavenumber (HW)(2800–3600 cm−1) Raman spectra from esophageal tissue in vivo. A total of 1172 in vivo FP/HW Raman spectra were acquired from 48 esophageal patients undergoing endoscopic examination. The total Raman dataset was split into two parts: 80% for training; while 20% for testing. Partial least squares-discriminant analysis (PLS-DA) and leave-one patient-out, cross validation (LOPCV) were implemented on training dataset to develop diagnostic algorithms for tissue classification. PLS-DA-LOPCV shows that simultaneous FP/HW Raman spectroscopy on training dataset provides a diagnostic sensitivity of 97.0% and specificity of 97.4% for ESCC classification. Further, the diagnostic algorithm applied to the independent testing dataset based on simultaneous FP/HW Raman technique gives a predictive diagnostic sensitivity of 92.7% and specificity of 93.6% for ESCC identification, which is superior to either FP or HW Raman technique alone. This work demonstrates that the simultaneous FP/HW fiber-optic Raman spectroscopy technique improves real-time in vivo diagnosis of esophageal neoplasia at endoscopy. PMID:26243571

  14. Plume Characterization of a Laboratory Model 22 N GPIM Thruster via High-Frequency Raman Spectroscopy

    Science.gov (United States)

    Williams, George J.; Kojima, Jun J.; Arrington, Lynn A.; Deans, Matthew C.; Reed, Brian D.; Kinzbach, McKenzie I.; McLean, Christopher H.

    2015-01-01

    The Green Propellant Infusion Mission (GPIM) will demonstrate the capability of a green propulsion system, specifically, one using the monopropellant, AF-M315E. One of the risks identified for GPIM is potential contamination of sensitive areas of the spacecraft from the effluents in the plumes of AF-M315E thrusters. Plume characterization of a laboratory-model 22 N thruster via optical diagnostics was conducted at NASA GRC in a space-simulated environment. A high-frequency pulsed laser was coupled with an electron-multiplied ICCD camera to perform Raman spectroscopy in the near-field, low-pressure plume. The Raman data yielded plume constituents and temperatures over a range of thruster chamber pressures and as a function of thruster (catalyst) operating time. Schlieren images of the near-field plume enabled calculation of plume velocities and revealed general plume structure of the otherwise invisible plume. The measured velocities are compared to those predicted by a two-dimensional, kinetic model. Trends in data and numerical results are presented from catalyst mid-life to end-of-life. The results of this investigation were coupled with the Raman and Schlieren data to provide an anchor for plume impingement analysis presented in a companion paper. The results of both analyses will be used to improve understanding of the nature of AF-M315E plumes and their impacts to GPIM and other future missions.

  15. Feasibility Study of Using High-Temperature Raman Spectroscopy for On-Line Monitoring and Product Control of the Glass Vitrification Process

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, C.F. Jr.; Piepel, G.F.; Li, H.; Elliott, M.L.; Su, Y.

    1999-01-04

    A pulse-gating Raman spectroscopy setup was developed in this project. The setup was capable of performing in-situ high-temperature Raman measurements for glasses at temperatures as high as 1412 C. In the literature, high-temperature Raman measurements have only been performed on thin films of glass to minimize black-body radiation effects. The pulse-gating Raman setup allows making high-temperature measurements for bulk melts while effectively minimizing black-body radiation effects. A good correlation was found between certain Raman characteristic parameters and glass melt temperature for sodium silicate glasses measured in this project. Comparisons were made between the high-temperature Raman data from this study and literature data. The results suggest that an optimization of the pulse-gating Raman setup is necessary to further improve data quality (i.e., to obtain data with a higher signal-to-noise ratio). An W confocal Raman microspectrometer with continuous wave laser excitation using a 325 nm excitation line was evaluated selectively using a transparent silicate glass ad a deep-colored high-level waste glass in a bulk quantity. The data were successfully collected at temperatures as high as approximately 1500 C. The results demonstrated that the UV excitation line can be used for high-temperature Raman measurements of molten glasses without black-body radiation interference from the melt for both transparent and deep-color glasses. Further studies are needed to select the best laser system that can be used to develop high-temperature Raman glass databases.

  16. Specificity and Strain-Typing Capabilities of Nanorod Array-Surface Enhanced Raman Spectroscopy for Mycoplasma pneumoniae Detection.

    Directory of Open Access Journals (Sweden)

    Kelley C Henderson

    Full Text Available Mycoplasma pneumoniae is a cell wall-less bacterial pathogen of the human respiratory tract that accounts for > 20% of all community-acquired pneumonia (CAP. At present the most effective means for detection and strain-typing is quantitative polymerase chain reaction (qPCR, which can exhibit excellent sensitivity and specificity but requires separate tests for detection and genotyping, lacks standardization between available tests and between labs, and has limited practicality for widespread, point-of-care use. We have developed and previously described a silver nanorod array-surface enhanced Raman Spectroscopy (NA-SERS biosensing platform capable of detecting M. pneumoniae with statistically significant specificity and sensitivity in simulated and true clinical throat swab samples, and the ability to distinguish between reference strains of the two main genotypes of M. pneumoniae. Furthermore, we have established a qualitative lower endpoint of detection for NA-SERS of < 1 genome equivalent (cell/μl and a quantitative multivariate detection limit of 5.3 ± 1 cells/μl. Here we demonstrate using partial least squares- discriminatory analysis (PLS-DA of sample spectra that NA-SERS correctly identified M. pneumoniae clinical isolates from globally diverse origins and distinguished these from a panel of 12 other human commensal and pathogenic mycoplasma species with 100% cross-validated statistical accuracy. Furthermore, PLS-DA correctly classified by strain type all 30 clinical isolates with 96% cross-validated accuracy for type 1 strains, 98% cross-validated accuracy for type 2 strains, and 90% cross-validated accuracy for type 2V strains.

  17. Raman Spectra of High-κ Dielectric Layers Investigated with Micro-Raman Spectroscopy Comparison with Silicon Dioxide

    Directory of Open Access Journals (Sweden)

    P. Borowicz

    2013-01-01

    Full Text Available Three samples with dielectric layers from high-κ dielectrics, hafnium oxide, gadolinium-silicon oxide, and lanthanum-lutetium oxide on silicon substrate were studied by Raman spectroscopy. The results obtained for high-κ dielectrics were compared with spectra recorded for silicon dioxide. Raman spectra suggest the similarity of gadolinium-silicon oxide and lanthanum-lutetium oxide to the bulk nondensified silicon dioxide. The temperature treatment of hafnium oxide shows the evolution of the structure of this material. Raman spectra recorded for as-deposited hafnium oxide are similar to the results obtained for silicon dioxide layer. After thermal treatment especially at higher temperatures (600°C and above, the structure of hafnium oxide becomes similar to the bulk non-densified silicon dioxide.

  18. High-pressure polymorphism of acetylsalicylic acid (aspirin): Raman spectroscopy

    Science.gov (United States)

    Crowell, Ethan L.; Dreger, Zbigniew A.; Gupta, Yogendra M.

    2015-02-01

    Micro-Raman spectroscopy was used to elucidate the high-pressure polymorphic behavior of acetylsalicylic acid (ASA), an important pharmaceutical compound known as aspirin. Using a diamond anvil cell (DAC), single crystals of the two polymorphic phases of aspirin existing at ambient conditions (ASA-I and ASA-II) were compressed to 10 GPa. We found that ASA-I does not transform to ASA-II, but instead transforms to a new phase (ASA-III) above ∼2 GPa. It is demonstrated that this transformation primarily introduces structural changes in the bonding and arrangement of the acetyl groups and is reversible upon the release of pressure. In contrast, a less dense ASA-II shows no transition in the pressure range studied, though it appears to exhibit a disordered structure above 7 GPa. Our results suggest that ASA-III is the most stable polymorph of aspirin at high pressures.

  19. Printable Graphene-based Thermoelectric Device with High Temperature Capability

    Science.gov (United States)

    Li, Tian; Chen, Yanan; Drew, Dennis; Hu, Liangbing; NanomaterialsEmerging Devices Collaboration

    Thermoelectric devices are of particular interest due to their capability to convert heat into electrical power. We demonstrate the use of a Graphene-based thermoelectric device that can generate output voltages of hundreds of millivolts with an illuminating Graphene strip as the blackbody source. Our proposed device is superior for thermoelectric conversion mainly due to its high temperature capability that yields a maximum Carnot efficiency limit of 90% (referenced to room temperature) and a high Seebeck coefficient. Our device is also macroscopic with good mechanical strength and stabilized performance, making it attractive for large scale and reliable thermoelectric devices.

  20. Raman forward scattering of high-intensity chirped laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, C.B.; Esarey, E.; Shadwick, B.A.; Leemans, W.P.

    2002-06-23

    Raman forward scattering of a high-intensity, short-duration, frequency-chirped laser pulse propagating in an underdense plasma is examined. The growth of the direct forward scattered light is calculated for a laser pulse with a linear frequency chirp in various spatio-temporal regimes. This includes a previously undescribed regime of strongly-coupled four-wave nonresonant interaction, which is important for relativistic laser intensities. In all regimes of forward scattering, it is shown that the growth rate increases (decreases) for positive (negative) frequency chirp. The effect of chirp on the growth rate is relatively minor, i.e., a few percent chirp yields few percent changes in the growth rates. Relation of these results to recent experiments is discussed.

  1. Highly reproducible surface-enhanced Raman scattering substrate for detection of phenolic pollutants

    Science.gov (United States)

    Zeng, Zhiqiang; Tang, Dan; Liu, Liwei; Wang, Yin; Zhou, Qingwei; Su, Shaoqiang; Hu, Die; Han, Bing; Jin, Mingliang; Ao, Xianyu; Zhan, Runze; Gao, Xingsen; Lu, Xubing; Zhou, Guofu; Senz, Stephan; Zhang, Zhang; Liu, Junming

    2016-11-01

    The ordering degree of nanostructures is the key to determining the uniformity of surface-enhanced Raman scattering (SERS). However, fabrication of large-area ordered nanostructures remains a challenge, especially with the ultrahigh-density (>1010 cm-2). Here, we report a fabrication of large-area ultrahigh-density ordered Ag@Al2O3/Ag core-shell nanosphere (NS) arrays with tunable nanostructures. The ultrahigh-density (2.8 × 1010 cm-2) ordered NS arrays over a large-area capability (diameter >4.0 cm) enable the uniform SERS signals with the relative standard deviation of less than 5%. The as-fabricated highly reproducible SERS substrate can be applied to detect trace phenolic pollutants in water. This work does not only provide a new route for synthesizing the ultrahigh-density ordered nanostructures, but also create a new class of SERS substrates with high sensitivity and excellent reproducibility.

  2. Semi-solid electrodes having high rate capability

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yet-Ming; Duduta, Mihai; Holman, Richard; Limthongkul, Pimpa; Tan, Taison

    2016-07-05

    Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode, a semi-solid cathode that includes a suspension of an active material and a conductive material in a liquid electrolyte, and an ion permeable membrane disposed between the anode and the cathode. The semi-solid cathode has a thickness in the range of about 250 .mu.m-2,500 .mu.m, and the electrochemical cell has an area specific capacity of at least 5 mAh/cm.sup.2 at a C-rate of C/2.

  3. Semi-solid electrodes having high rate capability

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Yet-Ming; Duduta, Mihai; Holman, Richard; Limthongkul, Pimpa; Tan, Taison

    2015-11-10

    Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode, a semi-solid cathode that includes a suspension of an active material and a conductive material in a liquid electrolyte, and an ion permeable membrane disposed between the anode and the cathode. The semi-solid cathode has a thickness in the range of about 250 .mu.m-2,500 .mu.m, and the electrochemical cell has an area specific capacity of at least 5 mAh/cm.sup.2 at a C-rate of C/2.

  4. An induction heating diamond anvil cell for high pressure and temperature micro-Raman spectroscopic measurements.

    Science.gov (United States)

    Shinoda, Keiji; Noguchi, Naoki

    2008-01-01

    A new external heating configuration is presented for high-temperature diamond anvil cell instruments. The supporting rockers are thermally excited by induction from an externally mounted copper coil passing a 30 kHz alternating current. The inductive heating configuration therefore avoids the use of breakable wires, yet is capable of cell temperatures of 1100 K or higher. The diamond anvil cell has no resistive heaters, but uses a single-turn induction coil for elevating the temperature. The induction coil is placed near the diamonds and directly heats the tungsten carbide rockers that support the diamond. The temperature in the cell is determined from a temperature-power curve calibrated by the ratio between the intensities of the Stokes and anti-Stokes Raman lines of silicon. The high-pressure transformation of quartz to coesite is successfully observed by micro-Raman spectroscopy using this apparatus. The induction heating diamond anvil cell is thus a useful alternative to resistively heated diamond anvil cells.

  5. Raman active high energy excitations in URu2Si2

    Science.gov (United States)

    Buhot, Jonathan; Gallais, Yann; Cazayous, Maximilien; Sacuto, Alain; Piekarz, Przemysław; Lapertot, Gérard; Aoki, Dai; Méasson, Marie-Aude

    2017-02-01

    We have performed Raman scattering measurements on URu2Si2 single crystals on a large energy range up to ∼1300 cm-1 and in all the Raman active symmetries as a function of temperature down to 15 K. A large excitation, active only in the Eg symmetry, is reported. It has been assigned to a crystal electric field excitation on the Uranium site. We discuss how this constrains the crystal electric field scheme of the Uranium ions. Furthermore, three excitations in the A1g symmetry are observed. They have been associated to double Raman phonon processes consistently with ab initio calculations of the phonons dispersion.

  6. Detection of nerve gases using surface-enhanced Raman scattering substrates with high droplet adhesion

    DEFF Research Database (Denmark)

    Hakonen, Aron; Rindzevicius, Tomas; Schmidt, Michael Stenbæk;

    2016-01-01

    we demonstrate that surface-enhanced Raman scattering (SERS) can be used for sensitive detection of femtomol quantities of two nerve gases, VX and Tabun, using a handheld Raman device and SERS substrates consisting of flexible gold-covered Si nanopillars. The substrate surface exhibits high droplet...

  7. Differential high-resolution stimulated CW Raman spectroscopy of hydrogen in a hollow-core fiber

    CERN Document Server

    Westergaard, Philip G; Petersen, Jan C

    2015-01-01

    We demonstrate sensitive high-resolution stimulated Raman measurements of hydrogen using a hollow-core photonic crystal fiber (HC-PCF). The Raman transition is pumped by a narrow linewidth (<50 kHz) 1064 nm continuous-wave (CW) fiber laser. The probe light is produced by a homebuilt CW optical parametric oscillator (OPO), tunable from around 800 nm to 1300 nm (linewidth ~ 5 MHz). These narrow linewidth lasers allow for an excellent spectral resolution of approximately 10^-4 cm^(-1). The setup employs a differential measurement technique for noise rejection in the probe beam, which also eliminates background signals from the fiber. With the high sensitivity obtained, Raman signals were observed with only a few mW of optical power in both the pump and probe beams. This demonstration allows for high resolution Raman identification of molecules and quantification of Raman signal strengths.

  8. Highly Stable PM Raman Fiber Laser at 1680 nm

    DEFF Research Database (Denmark)

    Svane, Ask Sebastian; Liu, Xiaomin; Rottwitt, Karsten

    2013-01-01

    We demonstrate thermal stabilization of a Raman fiber laser. At 1680 nm the laser emission exceeds 500 mW with a power variation below 0.5 %, both linewidth and wavelength variations are under 1 pm.......We demonstrate thermal stabilization of a Raman fiber laser. At 1680 nm the laser emission exceeds 500 mW with a power variation below 0.5 %, both linewidth and wavelength variations are under 1 pm....

  9. High Energy Telescope With Neutron Detection Capabilities (HETn)

    Science.gov (United States)

    Posner, A.; Wimmer-Schweingruber, R. F.; Böhm, E.; Böttcher, s.; Connell, J. J.; Dröge, W.; Hassler, D. M.; Heber, B.; Lopate, C.; McKibben, R. B.; Steigies, C. T.

    2007-01-01

    The High-Energy Telescope with neutron detection capabilities (HETn) for the Solar Orbiter will measure and resolve energetic charged particles, in particular electrons, proton, and heavy ions up to Fe including selected isotopes up to energies equivalen to the penetration depth of 100 MeV protons. The full active anti-coincidence encloses detectors sensitive to 1-30 MeV neutrons and 0.5-5 MeV X-/gamma-rays. The sensor consists of the angle-detecting inclined sensors (ADIS) solid-state detector detector telescope utilizing a shared calorimeter for total energy and X-/gamma-ray measurement. A separate plastic detector provides sensitivity to neutrons via the recoil process. HETn will open a new window on solar eruptive events with its neutron detection capability and allows determination of high-energy close to the Sun. Timing and spectral information on neutral particles (neutrons and X-/gamma rays ), on relativistic electrons and high-energy heavy ions will provide new insights into the processes which accelerate particles to high energies at the sun and into transport processes between the source and the spacecraft in the near-Sun environment.

  10. Semi-solid electrodes having high rate capability

    Science.gov (United States)

    Chiang, Yet-Ming; Duduta, Mihai; Holman, Richard; Limthongkul, Pimpa; Tan, Taison

    2016-06-07

    Embodiments described herein relate generally to electrochemical cells having high rate capability, and more particularly to devices, systems and methods of producing high capacity and high rate capability batteries having relatively thick semi-solid electrodes. In some embodiments, an electrochemical cell includes an anode and a semi-solid cathode. The semi-solid cathode includes a suspension of an active material of about 35% to about 75% by volume of an active material and about 0.5% to about 8% by volume of a conductive material in a non-aqueous liquid electrolyte. An ion-permeable membrane is disposed between the anode and the semi-solid cathode. The semi-solid cathode has a thickness of about 250 .mu.m to about 2,000 .mu.m, and the electrochemical cell has an area specific capacity of at least about 7 mAh/cm.sup.2 at a C-rate of C/4. In some embodiments, the semi-solid cathode slurry has a mixing index of at least about 0.9.

  11. High power transient characteristics and capability of NSRR

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takehiko; Kashima, Yoichi; Yachi, Shigeyasu; Yoshinaga, Makio; Terakado, Yoshibumi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Katanishi, Shoji [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2002-03-01

    In order to study fuel behavior under abnormal transients and accidents, the control system of the Nuclear Safety Research Reactor (NSRR) of the Japan Atomic Energy Research Institute (JAERI) was modified to achieve high power transients. With this new operational mode, called Shaped Pulse (SP), transients at the maximum power of 10 MW can be conducted for a few seconds. This new operational mode supplements the previous Natural Pulse (NP) operation at the maximum power of 23 GW for milliseconds. For high power transient operation, a simulator using a point kinetic model was developed, and characteristics of the NSRR in the new operational mode were examined through tests and calculations. With the new operational mode, new types of fuel irradiation tests simulating power oscillations of boiling water reactors (BWRs) can be conducted in the NSRR. Reactor characteristics and capability, such as control rod worth, feedback reactivity, and operational limits of the NSRR for SP operations are discussed. (author)

  12. High-wavenumber FT-Raman spectroscopy for in vivo and ex vivo measurements of breast cancer

    DEFF Research Database (Denmark)

    Garcia-Flores, A. F.; Raniero, L.; Canevari, R. A.;

    2011-01-01

    The identification of normal and cancer breast tissue of rats was investigated using high-frequency (HF) FT-Raman spectroscopy with a near-infrared excitation source on in vivo and ex vivo measurements. Significant differences in the Raman intensities of prominent Raman bands of lipids and protei...

  13. Solid State Raman Materials Characterization for High Average Power 1.3 micrometer Laser Frequency Shift

    Science.gov (United States)

    1999-01-01

    reflectivity at 1067 rim wavelength. Solid state phototrop filter based on gallium -scandium- gadolinium garnet doped with chromium was used as a passive Q-switch... gadolinium tungstate, KGd(W0 4)2 exhibited efficient Raman properties . In spite of the fact that its Raman gain coefficient at 1064 nm (6 cm/GW) is twice less...studied by high- temperature Raman scattering (HTRS) technique. According to [1], the lattice cell of KGd(W04) 2 low - temperature modification is a base

  14. Capability of tip-enhanced Raman spectroscopy about nanoscale analysis of strained silicon for semiconductor devices production

    Science.gov (United States)

    Lucia, Arianna; Cacioppo, Onofrio Antonino; Iulianella, Enrico; Latessa, Luca; Moccia, Giuseppe; Passeri, Daniele; Rossi, Marco

    2017-03-01

    Localized strained silicon was observed with a suitable resolution in a real semiconductor device by tip-enhanced Raman spectroscopy (TERS). The device was made via a standard industrial process and its silicon trench isolation structures were used for the silicon strain analysis obtaining results according to finite element method-based simulation data. We have achieved a reliable and repeatable enhancement factor obtaining a trace of strained silicon along the structure with suitable nanometer spatial resolution compatible with IC industry requirements. We demonstrate that the complexity to analyze a real 3D structure, directly from the production lines and not ad hoc realized, entails the challenges to individuate the optimal tip shape, tip contact angle, tip composition, tip positioning system, laser power, and wavelength to achieve an appropriate plasmon resonance inducing a relevant signal to noise ratio. This work gives the base to address the development in TERS optimization for real industrial applications.

  15. High Efficiency Pulse Acetone Liquid Raman Laser Using DCM Fluorescent Dye as the Enhancement Medium

    Institute of Scientific and Technical Information of China (English)

    CHENG Andrew Yuk-Sun; YANG Jing-Guo; CHAN Mau-Hing

    2006-01-01

    Pumped by a frequency-doubled Nd:YAG laser, 10-Hz repetition rate, 320-mJ pump energy, and 5.1-ns pulse width, a liquid Raman laser using acetone as the Raman shifting medium has been established. The residual pump laser pulse and the generated Stokes pulse are directed to a DCM dye cell for energy enhancement of the Stokes pulse. The Raman laser system is capable to produce a laser pulse at wavelength 630 nm, with single pulse energy of 120 mJ, peak power of 70 MW and an average power of 1200 mW. The energy conversion efficiency is 37.5%, or equivalently a quantum efficiency of 44.5%.

  16. New Micro-Raman Spectroscopy Systems for High-Temperature Studies in the Diamond Anvil Cell

    Science.gov (United States)

    Shim, S.; Lamm, R.; Rekhi, S.; Catalli, K.; Santillan, J.; Lundin, S.

    2005-12-01

    In order to measure high-quality Raman spectra at high temperature and pressure in either the resistance- or laser-heated diamond-anvil cell, we have developed two Raman systems at MIT, a dispersive and a nanosecond time-resolved Raman spectroscopy systems. The excitation source of the dispersive Raman system is an Ar/Kr mixed ion laser which has nine available laser lines with wavelengths between 457 and 752 nm. Near UV laser lines allow us to measure Raman spectra up to 1200 K by shifting the spectral range of Raman modes away from intense thermal radiation. Near IR lines can be used for highly fluorescent materials. Three 500 mm spectrometers (Trivista spectrometer, Acton Research) are configured to operate in either single, triple subtractive, or triple additive mode combined with a liquid nitrogen cooled CCD detector. Holographic notch filters allow for high throughput in the single mode, which is ideal for weak Raman scattering. The subtractive triple mode allows detection of phonon modes to 5 cm-1 from the Raleigh line. The nanosecond time-resolved Raman system is designed for measurements above 1000 K. Previous studies at ambient pressure have shown that time-resolved Raman spectroscopy is the most effective technique to reject strong thermal radiation above 1000 K. We achieve nanosecond time resolution by synchronizing a frequency-doubled pulse Nd:YLF laser (527 nm, 0.1-10 kHz rep rate, 10-100 ns pulse width) with an intensified gated CCD detector (>5 ns gate width). This system is combined with a laser heating system (Nd:YLF laser, 1053 nm, TEM00, 45 W). Temperature is measured using both spectroradiometry and Raman thermometry methods. Our systems are designed to study phase relations and thermodynamic properties of mantle minerals at high P-T. Using these systems, we have measured the phase transition in (Mg0.9Fe0.1)SiO3 pyroxene at 300-1700 K and 0 GPa, and the dehydration of serpentine at 2-8 GPa and 300-900 K. We also have found that the time

  17. Developing Flexible, High Performance Polymers with Self-Healing Capabilities

    Science.gov (United States)

    Jolley, Scott T.; Williams, Martha K.; Gibson, Tracy L.; Caraccio, Anne J.

    2011-01-01

    Flexible, high performance polymers such as polyimides are often employed in aerospace applications. They typically find uses in areas where improved physical characteristics such as fire resistance, long term thermal stability, and solvent resistance are required. It is anticipated that such polymers could find uses in future long duration exploration missions as well. Their use would be even more advantageous if self-healing capability or mechanisms could be incorporated into these polymers. Such innovative approaches are currently being studied at the NASA Kennedy Space Center for use in high performance wiring systems or inflatable and habitation structures. Self-healing or self-sealing capability would significantly reduce maintenance requirements, and increase the safety and reliability performance of the systems into which these polymers would be incorporated. Many unique challenges need to be overcome in order to incorporate a self-healing mechanism into flexible, high performance polymers. Significant research into the incorporation of a self-healing mechanism into structural composites has been carried out over the past decade by a number of groups, notable among them being the University of I1linois [I]. Various mechanisms for the introduction of self-healing have been investigated. Examples of these are: 1) Microcapsule-based healant delivery. 2) Vascular network delivery. 3) Damage induced triggering of latent substrate properties. Successful self-healing has been demonstrated in structural epoxy systems with almost complete reestablishment of composite strength being achieved through the use of microcapsulation technology. However, the incorporation of a self-healing mechanism into a system in which the material is flexible, or a thin film, is much more challenging. In the case of using microencapsulation, healant core content must be small enough to reside in films less than 0.1 millimeters thick, and must overcome significant capillary and surface

  18. A high capability teleoperated vehicle for hazardous applications

    Energy Technology Data Exchange (ETDEWEB)

    Dudar, A.M.; Witherspoon, R.L.

    1995-09-01

    The Robotics Development Group at the Savannah River Site is developing a high performance teleoperated vehicle for use in radioactive and hazardous environments. The three-wheeled vehicle incorporates a highly dexterous 6 degree-of-freedom (DOF), hydraulically-powered manipulator made by Schilling Development, Inc. The teleoperator is called Little MoRT (MObile Radio-controlled Teleoperator) and is a modified version of a commercially available, battery-powered, warehouse vehicle. Little MoRT is controlled remotely by a universal robot controller either through a radio frequency link or a tethered cable. Six video cameras and a microphone provide the operator with audio-visual feedback of the vehicle and its surrounding environment. The vehicle also incorporates a hydraulic power unit consisting of a propane-driven engine for powering the Schilling manipulator. Little MoRT is capable of operating in outdoor as well as indoor environments and is well suited for decontamination and decommissioning activities such as dismantling, sorting, and surveying of radioactive waste.

  19. Development of High Temperature Capacitor Technology and Manufacturing Capability

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2011-05-15

    The goal of the Development of High Temperature Capacitor Technology and Manufacturing Capability program was to mature a production-ready supply chain for reliable 250°C FPE (fluorinated polyester) film capacitors by 2011. These high-temperature film capacitors enable both the down hole drilling and aerospace industries by enabling a variety of benefits including: - Deeper oil exploration in higher temperature and pressure environments - Enabling power electronic and control equipment to operate in higher temperature environments - Enabling reduced cooling requirements of electronics - Increasing reliability and life of capacitors operating below rated temperature - Enabling capacitors to handle higher electrical losses without overheating. The key challenges to bringing the FPE film capacitors to market have been manufacturing challenges including: - FPE Film is difficult to handle and wind, resulting in poor yields - Voltage breakdown strength decreases when the film is wound into capacitors (~70% decrease) - Encapsulation technologies must be improved to enable higher perature operation - Manufacturing and test cycle time is very long As a direct result of this program most of the manufacturing challenges have been met. The FPE film production metalization and winding yield has increased to over 82% from 70%, and the voltage breakdown strength of the wound capacitors has increased 270% to 189 V/μm. The high temperature packaging concepts are showing significant progress including promising results for lead attachments and hermetic packages at 200°C and non-hermetic packages at 250°C. Manufacturing and test cycle time will decrease as the market for FPE capacitors develops.

  20. 2-D straw detectors with high rate capability

    CERN Document Server

    Kuchinskiy, N A; Duginov, V N; Zyazyulya, F E; Korenchenko, A S; Kolesnikov, A O; Kravchuk, N P; Movchan, S A; Rudenko, A I; Smirnov, V S; Khomutov, N V; Chekhovsky, V A; Lobko, A S; Misevich, O V

    2015-01-01

    Precise measurement of straw axial coordinate (along the anode wire) with accuracy compatible with straw radial coordinate determination by drift time measurement and increase of straw detector rate capability by using straw cathode readout instead of anode readout are presented.

  1. Power scaling of high efficiency 1.5micron cascaded Raman fiber lasers

    CERN Document Server

    Supradeepa, V R

    2013-01-01

    High power fiber lasers operating at the 1.5micron wavelength region have attractive features like eye-safety and atmospheric transparency, and cascaded Raman fiber lasers offer a convenient method to obtain high power sources at these wavelengths. A limitation to power scaling however has been the lower conversion efficiency of these lasers. We recently introduced a high efficiency architecture for high power cascaded Raman fiber lasers applicable for 1.5micron fiber lasers. Here we demonstrate further power scaling using this new architecture. Using numerical simulations we identify the ideal operating conditions for the new architecture. We demonstrate a high efficiency 1480nm cascaded Raman fiber laser with an output power of 301 W, comparable to record power levels achieved with rare-earth doped fiber lasers in the 1.5 micron wavelength region.

  2. High pressure Raman and x-ray diffraction studies on the decomposition of tungsten carbonyl

    Science.gov (United States)

    Garimella, Subrahmanyam; Drozd, Vadym; Durygin, Andriy; Chen, Jiuhua

    2012-06-01

    Polycrystalline tungsten hexacarbonyl, W(CO)6, was studied using in situ Raman spectroscopy and synchrotron x-ray diffraction (XRD) at high pressures up to 60 GPa in a diamond anvil cell. High pressure causes collapse of the Oh molecular symmetry in W(CO)6 leading to decomposition of the carbonyl compound. The decomposed material has characteristic of δ(OCO), v(C=C), v(C=O), and adsorbed CO Raman features. High pressure XRD results showed the irreversible amorphization of tungsten hexacarbonyl. A solid state vibrational coupling mechanism is proposed to explain the formation of δ(OCO) units. Further, the high pressure Raman results of W, Mo, and Cr hexacarbonyls are compared and the breakdown of the Dewar-Chatt-Duncanson model in this family is qualitatively discussed.

  3. Astronomical liquid mirrors as highly ultrasensitive, broadband-operational surface-enhanced Raman scattering-active substrates.

    Science.gov (United States)

    Lu, Tai-Yen; Lee, Yang-Chun; Yen, Yu-Ting; Yu, Chen-Chieh; Chen, Hsuen-Li

    2016-03-15

    In this study, we found that an astronomical liquid mirror can be prepared as a highly ultrasensitive, low-cost, highly reproducible, broadband-operational surface-enhanced Raman scattering (SERS)-active substrate. Astronomical liquid mirrors are highly specularly reflective because of their perfectly dense-packed silver nanoparticles; they possess a large number and high density of hot spots that experience a very high intensity electric field, resulting in excellent SERS performance. When using the liquid mirror-based SERS-active substrate to detect 4-aminothiophenol (4-ATP), we obtained measured analytical enhancement factors (AEFs) of up to 2.7×10(12) and detection limits as low as 10(-15) M. We also found that the same liquid mirror could exhibit superior SERS capability at several distinct wavelengths (532, 632.8, and 785 nm). The presence of hot spots everywhere in the liquid mirror provided highly repeatable Raman signals from low concentrations of analytes. In addition, the astronomical liquid mirrors could be transferred readily onto cheap, flexible, and biodegradable substrates and still retain their excellent SERS performance, suggesting that they might find widespread applicability in various (bio)chemical detection fields.

  4. Raman Spectroscopy of Serpentine and Reaction Products at High Pressure Using a Diamond Anvil Cell

    Science.gov (United States)

    Burgess, K.; Zinin, P.; Odake, S.; Fryer, P.; Hellebrand, E.

    2012-12-01

    Serpentine is one of the most abundant hydrous phases in the altered subducting plate, and contributes a large portion of the water flux in subduction zones. Measuring and understanding the structural changes in serpentine with pressure aids our understanding of the processes ongoing in oceanic crust and subduction zones. We have conducted high-pressure/high-temperature experiments on serpentine and its dehydration reaction products using a diamond anvil cell. We used the multifunctional in-situ measurement system equipped with a Raman device and laser heating system at the University of Hawaii. Well-characterized natural serpentinite was used in the study. Pressure was determined using the shift of the fluorescence line of a ruby placed next to the sample. Raman spectra of serpentine were obtained at higher pressures than previously published, up to 15 GPa; the peak shift with pressure fits the model determined by Auzende et al. [2004] at lower pressures. Heating was done at several different pressures up to 20 GPa, and reaction products were identified using Raman. Micro-Raman techniques allow us to determine reaction progress and heterogeneity within natural samples containing olivine and serpentine. Auzende, A-L., I. Daniel, B. Reynard, C. Lemaire, F. Guyot (2004). High-pressure behavior of serpentine minerals: a Raman spectroscopic study. Phys. Chem. Minerals 31 269-277.

  5. Raman investigation on the behavior of parasibirskite CaHBO3 at high pressure

    Science.gov (United States)

    Goryainov, S. V.; Pan, Y.; Smirnov, M. B.; Sun, W.; Mi, J.-X.

    2017-02-01

    Knowledge about the stability of hydrous borates and borosilicates at high pressures are of critical importance to our understanding on the boron geochemical cycle. Raman spectroscopic measurements of parasibirskite CaHBO3, containing the [BO2(OH)] groups, have been made to pressures up to 5.4 GPa. The Raman data show that a progressive structural evolution from ambient pressure to 5.4 GPa can be accounted for by the same monoclinic phase P21/m, where the splitting of several Raman bands observed at some pressures is interpreted as the effect of the complex disordering in the H-bond network that has bifurcated H-bonds and ½-occupied H sites. There is no unambiguous evidence for phase transition to the ordered P21 monoclinic phase predicted by first-principles calculations at T = 0 K (W. Sun et al., Can. Miner., 2011). On the contrary, the disordering of parasibirskite, evidenced by the widening and attenuating Raman spectra, increases markedly at high pressures above 4.5 GPa that results in incipient amorphization. Comparison of theoretical (lattice-dynamical) and experimental Raman spectra allows the reliable interpretation of almost all observed bands. The strongest symmetric B-O stretching band v1 at the wavenumber 908 cm- 1, which is split into a doublet at high pressures, exhibits a shift rate of 4.22 cm- 1/GPa for the main component.

  6. Highly Sensitive Surface Enhanced Raman Spectroscopy from Ag Nanoparticles Decorated Graphene Sheet

    Directory of Open Access Journals (Sweden)

    Hui Song

    2014-01-01

    Full Text Available Surface enhanced Raman spectroscopy (SERS is a powerful analytical technique and has been most intensively studied. In this work, electroless deposition is proposed for Ag nanoparticles (NPs decorated on chemical vapor deposition (CVD growth graphene sheets (GS to create hybrid SERS substrate. From three aspects of size distribution, morphology, and coverage, Ag NPs controllable decoration on GS and SERS enhancement factors of the hybrid SERS substrate is investigated. 200–300 times enhanced SERS intensities are detected from the Ag NPs on GS hybrid as compared to pure GS. Controllable decoration is crucial for improving SERS enhancement factors βEF, because βEF from quasi cubic Ag NPs on GS is 6.53 times stronger than that from spheric one; 1.6 times βEF is detected while the Ag NPs size distribution is reduced to half, and when the coverage is doubled, βEF is nearly doubled. This controllable Ag NPs/GS hybrid is capable of serving as a high performance SERS substrate for efficient chemical and biological sensing applications.

  7. Characterisation of Systems for Raman-Assisted High-Speed Wavelength Conversion

    DEFF Research Database (Denmark)

    Galili, Michael; Oxenløwe, Leif Katsuo; Zibar, Darko

    2005-01-01

    Raman-assisted wavelength conversion for ultra-high speed data is characterised in approaches: a novel scheme based on cross-phase modulation using specially designed notch filters and a 160 Gb/s experiment based on self-phase modulation......Raman-assisted wavelength conversion for ultra-high speed data is characterised in approaches: a novel scheme based on cross-phase modulation using specially designed notch filters and a 160 Gb/s experiment based on self-phase modulation...

  8. Demonstration of resonant backward Raman amplification in high-density gas-jet plasma

    Science.gov (United States)

    Wu, Z. H.; Zhou, K. N.; Zheng, X. M.; Wei, X. F.; Zhu, Q. H.; Su, J. Q.; Xie, N.; Jiao, Z. H.; Peng, H.; Wang, X. D.; Sun, L.; Li, Q.; Huang, Z.; Zuo, Y. L.

    2016-10-01

    Backward Raman amplification was observed in a 0.7 mm-long high-density gas jet plasma. The 800 nm 30 fs seed pulse was amplified by a factor  ∼28, with an output energy of 2.8 mJ. The output spectra showed that the waveband around 800 nm was significantly amplified. The experimental result demonstrated that the resonant Raman amplification can be realized in high-density plasma against strong plasma instability.

  9. High-speed stimulated Raman scattering microscopy for studying the metabolic diversity of motile Euglena gracilis

    Science.gov (United States)

    Suzuki, Y.; Wakisaka, Y.; Iwata, O.; Nakashima, A.; Ito, T.; Hirose, M.; Domon, R.; Sugawara, M.; Tsumura, N.; Watarai, H.; Shimobaba, T.; Suzuki, K.; Goda, K.; Ozeki, Y.

    2017-02-01

    Microalgae have been receiving great attention for their ability to produce biomaterials that are applicable for food supplements, drugs, biodegradable plastics, and biofuels. Among such microalgae, Euglena gracilis has become a popular species by virtue of its capability of accumulating useful metabolites including paramylon and lipids. In order to maximize the production of desired metabolites, it is essential to find ideal culturing conditions and to develop efficient methods for genetic transformation. To achieve this, understanding and controlling cell-to-cell variations in response to external stress is essential, with chemically specific analysis of microalgal cells including E. gracilis. However, conventional analytical tools such as fluorescence microscopy and spontaneous Raman scattering are not suitable for evaluation of diverse populations of motile microalgae, being restricted either by the requirement for fluorescent labels or a limited imaging speed, respectively. Here we demonstrate video-rate label-free metabolite imaging of live E. gracilis using stimulated Raman scattering (SRS) - an optical spectroscopic method for probing the vibrational signatures of molecules with orders of magnitude higher sensitivity than spontaneous Raman scattering. Our SRS's highspeed image acquisition (27 metabolite images per second) allows for population analysis of live E. gracilis cells cultured under nitrogen-deficiency - a technique for promoting the accumulation of paramylon and lipids within the cell body. Thus, our SRS system's fast imaging capability enables quantification and analysis of previously unresolvable cell-to-cell variations in the metabolite accumulation of large motile E. gracilis cell populations.

  10. Development of a high-throughput solution for crystallinity measurement using THz-Raman spectroscopy

    Science.gov (United States)

    Roy, Anjan; Fosse, Jean-Charles; Fernandes, Filipe; Ringwald, Alexandre; Ho, Lawrence

    2017-02-01

    Rapid identification and the quantitative analysis of crystalline content and the degree of crystallinity is important in pharmaceuticals and polymer manufacturing. Crystallinity affects the bioavailability of pharmaceutical molecules and there is a strong correlation between the performance of polymers and their degree of crystallinity. Low frequency/THz-Raman spectroscopy has enabled determination of crystalline content in materials as a complementary method to X-ray powder diffraction. By incorporating motion stages and microplates, we have extended the applicability of THz-Raman technology to high-throughput screening applications. We describe here a complete THz-Raman microplate reader, with integrated laser, optics, spectrograph and software that are necessary for detecting low-frequency Raman signals. In powder materials scattering is also affected by particle size and the presence of cavities, which lead to a lack of precision and repeatability in Raman intensity measurements. We address this problem by spatial averaging using specific stage motion patterns. This design facilitates rapid and precise measurement of low-frequency vibrational modes, differentiation of polymorphs and other structural characteristics for applications in pharmaceuticals, nano- and bio-materials and for the characterization of industrial polymers where XRPD is commonly used.

  11. High-Performance Versatile Setup for Simultaneous Brillouin-Raman Microspectroscopy

    Directory of Open Access Journals (Sweden)

    F. Scarponi

    2017-07-01

    Full Text Available Brillouin and Raman scattering spectroscopy are established techniques for the nondestructive contactless and label-free readout of mechanical, chemical, and structural properties of condensed matter. Brillouin-Raman investigations currently require separate measurements and a site-matched approach to obtain complementary information from a sample. Here, we demonstrate a new concept of fully scanning multimodal microspectroscopy for simultaneous detection of Brillouin and Raman light scattering in an exceptionally wide spectral range, from fractions of GHz to hundreds of THz. It yields an unprecedented 150-dB contrast, which is especially important for the analysis of opaque or turbid media such as biomedical samples, and spatial resolution on a subcellular scale. We report the first applications of this new multimodal method to a range of systems, from a single cell to the fast reaction kinetics of a curing process, and the mechanochemical mapping of highly scattering biological samples.

  12. High-Performance Versatile Setup for Simultaneous Brillouin-Raman Microspectroscopy

    Science.gov (United States)

    Scarponi, F.; Mattana, S.; Corezzi, S.; Caponi, S.; Comez, L.; Sassi, P.; Morresi, A.; Paolantoni, M.; Urbanelli, L.; Emiliani, C.; Roscini, L.; Corte, L.; Cardinali, G.; Palombo, F.; Sandercock, J. R.; Fioretto, D.

    2017-07-01

    Brillouin and Raman scattering spectroscopy are established techniques for the nondestructive contactless and label-free readout of mechanical, chemical, and structural properties of condensed matter. Brillouin-Raman investigations currently require separate measurements and a site-matched approach to obtain complementary information from a sample. Here, we demonstrate a new concept of fully scanning multimodal microspectroscopy for simultaneous detection of Brillouin and Raman light scattering in an exceptionally wide spectral range, from fractions of GHz to hundreds of THz. It yields an unprecedented 150-dB contrast, which is especially important for the analysis of opaque or turbid media such as biomedical samples, and spatial resolution on a subcellular scale. We report the first applications of this new multimodal method to a range of systems, from a single cell to the fast reaction kinetics of a curing process, and the mechanochemical mapping of highly scattering biological samples.

  13. High-resolution inverse Raman and resonant-wave-mixing spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rahn, L.A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    These research activities consist of high-resolution inverse Raman spectroscopy (IRS) and resonant wave-mixing spectroscopy to support the development of nonlinear-optical techniques for temperature and concentration measurements in combustion research. Objectives of this work include development of spectral models of important molecular species needed to perform coherent anti-Stokes Raman spectroscopy (CARS) measurements and the investigation of new nonlinear-optical processes as potential diagnostic techniques. Some of the techniques being investigated include frequency-degenerate and nearly frequency-degenerate resonant four-wave-mixing (DFWM and NDFWM), and resonant multi-wave mixing (RMWM).

  14. High-pressure behavior of solid nitrobenzene: Combined Raman spectroscopy and DFT-D calculations study

    Science.gov (United States)

    Wang, Wen-Peng; Liu, Fu-Sheng; Liu, Qi-Jun; Zhang, Lin-Ji; Wang, Yi-Gao; Liu, Zheng-Tang

    2016-09-01

    Nitrobenzene (NB), a simplest structure of the aromatic nitro compounds, was investigated as a model for understanding structural properties in nitro derivatives of benzene and anilines. Using the Raman spectroscopic technique, the vibrational modes of solid NB were examined under hydrostatic compression up to 10 GPa. The Raman spectra indicated that a subtle phase transition occurred around 5 GPa. Also, the dispersion corrected density functional theory (DFT-D) calculations were performed to provide further insight into pressure effects on the molecular geometry. The calculated data suggested that NB molecules were distorted, and molecular conformation was readjusted when the phase transition with vibrational changes took place under high-pressure.

  15. High-Power Continuous-Wave Directly-Diode-Pumped Fiber Raman Lasers

    Directory of Open Access Journals (Sweden)

    Tianfu Yao

    2015-11-01

    Full Text Available We describe novel fiber Raman lasers pumped directly by spectrally combined high power multimode laser diodes at 975 nm and emitting at 1019 nm. With a commercial multimode graded-index fiber, we reached 20 W of laser output power with a record slope efficiency of 80%. With an in-house double-clad fiber, the beam quality improved to M2 = 1.9, albeit with lower output power and slope efficiency due to higher fiber loss. We believe this is the first publication of a fiber Raman laser cladding-pumped directly by diodes.

  16. Superconductivity-induced phononic effects in high-temperature superconductors: Raman study

    Energy Technology Data Exchange (ETDEWEB)

    Limonov, M. [Ioffe Physico-Technical Institute, Politekhnicheskaya 26, 194021 St. Petersburg (Russian Federation); Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13, Shinonome 1-Chome, Koto-ku, Tokyo 135-0062 (Japan); Lee, S.; Masui, T.; Uchiyama, H.; Tajima, S. [Superconductivity Research Laboratory, International Superconductivity Technology Center, 10-13, Shinonome 1-Chome, Koto-ku, Tokyo 135-0062 (Japan); Yamanaka, A. [Chitose Institute of Science and Technology, Chitose, Hokkaido 066-8655 (Japan)

    2004-11-01

    Raman scattering spectra of (123) and Bi-based high-temperature superconductors (HTSC) with different doping levels have been investigated. It is demonstrated that phonons in HTSC can provide unique information on energy, symmetry, temperature- and doping-dependencies of the superconducting gap and pseudogap. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  17. High-speed molecular spectral imaging of tissue with stimulated Raman scattering

    Science.gov (United States)

    Ozeki, Yasuyuki; Umemura, Wataru; Otsuka, Yoichi; Satoh, Shuya; Hashimoto, Hiroyuki; Sumimura, Kazuhiko; Nishizawa, Norihiko; Fukui, Kiichi; Itoh, Kazuyoshi

    2012-12-01

    To date, medical imaging of tissues has largely relied on time-consuming staining processes, and there is a need for rapid, label-free imaging techniques. Stimulated Raman scattering microscopy offers a three-dimensional, real-time imaging capability with chemical specificity. However, it can be difficult to differentiate between several constituents in tissues because their spectral characteristics can overlap. Furthermore, imaging speeds in previous multispectral stimulated Raman scattering imaging techniques were limited. Here, we demonstrate label-free imaging of tissues by 30 frames/s stimulated Raman scattering microscopy with frame-by-frame wavelength tunability. To produce multicolour images showing different constituents, spectral images were processed by modified independent component analysis, which can extract small differences in spectral features. We present various imaging modalities such as two-dimensional spectral imaging of rat liver, two-colour three-dimensional imaging of a vessel in rat liver, spectral imaging of several sections of intestinal villi in mouse, and in vivo spectral imaging of mouse ear skin.

  18. Raman Capabilities for Aerosol Characterization.

    Science.gov (United States)

    1980-11-01

    Electronics Research and Development Command, Atmospheric Sciences Laboratory, White Sands Missile Range, New Mexico . UNCLASSIFIED USCUMITY CLASSIICATION...PROGRAM ELEMENT. PROJECT. TASK Yale University AREA A WORK UNIT MUERtS Department of Engineering and Applied Sciern e 15030-GS New Haven, CT 06520 11

  19. The research of digital circuit system for high accuracy CCD of portable Raman spectrometer

    Science.gov (United States)

    Yin, Yu; Cui, Yongsheng; Zhang, Xiuda; Yan, Huimin

    2013-08-01

    The Raman spectrum technology is widely used for it can identify various types of molecular structure and material. The portable Raman spectrometer has become a hot direction of the spectrometer development nowadays for its convenience in handheld operation and real-time detection which is superior to traditional Raman spectrometer with heavy weight and bulky size. But there is still a gap for its measurement sensitivity between portable and traditional devices. However, portable Raman Spectrometer with Shell-Isolated Nanoparticle-Enhanced Raman Spectroscopy (SHINERS) technology can enhance the Raman signal significantly by several orders of magnitude, giving consideration in both measurement sensitivity and mobility. This paper proposed a design and implementation of driver and digital circuit for high accuracy CCD sensor, which is core part of portable spectrometer. The main target of the whole design is to reduce the dark current generation rate and increase signal sensitivity during the long integration time, and in the weak signal environment. In this case, we use back-thinned CCD image sensor from Hamamatsu Corporation with high sensitivity, low noise and large dynamic range. In order to maximize this CCD sensor's performance and minimize the whole size of the device simultaneously to achieve the project indicators, we delicately designed a peripheral circuit for the CCD sensor. The design is mainly composed with multi-voltage circuit, sequential generation circuit, driving circuit and A/D transition parts. As the most important power supply circuit, the multi-voltage circuits with 12 independent voltages are designed with reference power supply IC and set to specified voltage value by the amplifier making up the low-pass filter, which allows the user to obtain a highly stable and accurate voltage with low noise. What's more, to make our design easy to debug, CPLD is selected to generate sequential signal. The A/D converter chip consists of a correlated

  20. 1.5-μm low threshold, high efficiency Erbium-Raman random fiber laser

    Science.gov (United States)

    Wu, H.; Wang, Z. N.; Sun, W.; He, Q. H.; Rao, Y. J.

    2017-04-01

    We report a low threshold, high efficiency random fiber laser with hybrid Erbium-Raman gain. The numerical analysis is made to describe the power performance of the proposed Erbium-Raman random fiber laser and reveal the high efficiency generation in this simple configuration. Thanks to the hybrid gain, the experimentally achieved laser threshold has been reduced to 60 mW. The optical conversion efficiency is of record high in the 1.5 μm regime, reaching 61.5% when pump power is 2 W. This work provides an effective way to generate high efficiency stable 1.5 μm random lasing, which could have important applications in optical fiber sensing and communication.

  1. Raman studies of hexagonal MoO{sub 3} at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, C.C.; Zhang, Z.M.; Dai, R.C.; Zhang, J.W.; Ding, Z.J. [Hefei National Laboratory for Physical Sciences at Microscale, Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zheng, L. [Department of Nanomaterials and Nanochemistry, Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Wang, Z.P. [The Centre for Physical Experiments, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2011-05-15

    The transition-metal oxide MoO{sub 3} is an important semiconductor and has various technological applications in catalysts, electrochromic and photochromic devices, gas sensors, and battery electrodes. In this study, the hexagonal MoO{sub 3} prepared by a hydrothermal method is in morphology of microrod with diameter of 0.8-1.2 {mu}m and length of 2.0-4.3 {mu}m. Its structural stability was investigated by an in situ Raman scattering method in a diamond anvil cell up to 28.7 GPa at room temperature. The new Raman peak around 1000 cm{sup -1} implies that a phase transition from hexagonal to amorphous starts at 5.6 GPa, and the evolution of the Raman spectra indicates that the structural transition is completed at about 13.2 GPa. After releasing pressure to ambient condition, the Raman spectrum pattern of the high pressure phase was retained, revealing that the phase transition is irreversible. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Quantitative Raman imaging investigations of mixing phenomena in high-pressure cryogenic jets.

    Science.gov (United States)

    Decker, M; Schik, A; Meier, U E; Stricker, W

    1998-08-20

    A two-dimensional Raman technique was used to investigate mixing phenomena of cryogenic jets under both supercritical and transcritical conditions. The aim of this study was to enlarge the experimental data basis for modeling purposes and to provide quantitative information to help to improve the design of injectors for high-pressure rocket engine combustion chambers. Cryogenic nitrogen, which served as substitute for liquid O(2), was injected into N(2) at room temperature at pressures up to 6.0 MPa. The liquid N(2) jet could be atomized by a coaxial H(2) flow. Raman scattering was generated with a XeF excimer laser. The resulting signal images were discriminated against background by spectral filtering and preferential detection of light with a polarization corresponding to the polarization of the laser, thus making use of the conserved polarization of the Raman-scattered light. The Raman images were converted into density distributions of N(2) and H(2), respectively, as well as into temperature distributions for a variety of experimental conditions.

  3. ALMA's high-cadence imaging capabilities for solar observations

    CERN Document Server

    Wedemeyer, Sven

    2015-01-01

    The Atacama Large Millimeter/submillimeter Array offers an unprecedented view of our Sun at sub-/millimeter wavelengths. The high spatial, temporal, and spectral resolution facilitates the measurement of gas temperatures and magnetic fields in the solar chromosphere with high precision. The anticipated results will revolutionize our understanding of the solar atmosphere and may in particular result in major steps towards solving the coronal heating problem. Based on state-of-the-art 3D radiation magnetohydrodynamic simulations, we calculate the emergent continuum intensity (and thus brightness temperature maps) in the wavelength range accessed by ALMA and simulate instrumental effects for different array configurations. First results show that the local gas temperature can be closely mapped with ALMA and that much of the complex small-scale chromospheric pattern can be resolved.

  4. Silica Cladding of Ag Nanoparticles for High Stability and Surface-Enhanced Raman Spectroscopy Performance.

    Science.gov (United States)

    Zhao, Miaomiao; Guo, Hao; Liu, Wenyao; Tang, Jun; Wang, Lei; Zhang, Binzhen; Xue, Chenyang; Liu, Jun; Zhang, Wendong

    2016-12-01

    For high-precision biochemical sensing, surface-enhanced Raman spectroscopy (SERS) has been demonstrated to be a highly sensitive spectroscopic analytical method and Ag is considered to be the best material for SERS performance. Due to the high surface activity of Ag nanoparticles, the high stability of Ag nanostructures, especially in moist environments, is one of the key issues that need to be solved. A method for silica (SiO2) cladding of Ag nanoparticles (NPs) is demonstrated here for high sensitivity and long-term stability when putted in aqueous solution. The chemically inert, transparent, hydrophilic, and bio-compatible SiO2 surface acts as the protection layer for the Ag nanoparticles, which can also enhance the Raman intensity to a certain extent. In our study, the Ag@SiO2 core-shell substrate can detect crystal violet solutions with molar concentrations down to 10(-12) M. After 24 h of immersion, the reduction in Raman scattering intensity is about 85 % for sole Ag NP films, compared to 12 % for the Ag coated with a 10-nm SiO2 layer. This thickness was found to be optimum for Ag@SiO2 core-shell substrates with long-term stability and high SERS activity.

  5. Pressure estimation using the ‘diamond Raman scale’ at low pressures in diamond anvil cell experiments using a highly confocal Raman system

    Science.gov (United States)

    Fujii, Taku; Ohfuji, Hiroaki

    2015-02-01

    Pressure estimation using the frequency shift of the diamond Raman peak from the anvil culet is readily and widely used in diamond anvil cell experiments along with the conventional ruby fluorescence method. Here, we propose a modified diamond Raman scale particularly designed for pressure measurement below ~10 GPa. A series of experiments were conducted using a highly confocal Raman system and H2O, ethanol/methanol mixture and NaCl samples loaded in a rhenium gasket which was pre-indented to 40-60 or 100-110 μm thick. The result showed that the frequency of the diamond Raman peak from the anvil culet increases linearly with pressure between 1 and 13 GPa, when using a sufficiently pre-indented (40-60 μm thick) gasket. The frequency shifts are calibrated against the pressure determined by the ruby fluorescence method, which is an alternative pressure scale. In addition, a preliminary measurement at high temperature up to 575 K suggests the potential application of this method for high temperature experiments.

  6. Acquisition of a Modular, Multi-laser, Raman-AFM Instrument for Multdisciplinary Research

    Science.gov (United States)

    2015-04-28

    Acquisition of a Modular, Multi-laser, Raman- AFM Instrument for Multdisciplinary Research A four-laser, confocal Raman/Atomic Force Scanning...microscope (Raman- AFM ) (priced at ~ $496,000) has been acquired From Horiba Scientific. Acquisition of this instrument has enhanced the research and...capabilities as well as provides high resolution topographical and depth imaging capabilities through the AFM . The views, opinions and/or findings

  7. Vibrational imaging based on stimulated Raman scattering microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nandakumar, P; Kovalev, A; Volkmer, A [3. Physikalisches Institut, Universitaet Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany)], E-mail: a.volkmer@physik.uni-stuttgart.de

    2009-03-15

    A stimulated Raman scattering microscope with near-infrared picosecond laser pulses at high repetition rates (76 MHz) and radio-frequency lock-in detection is accomplished. Based on stimulated Raman loss detection, we demonstrate noninvasive point-by-point vibrational mapping of chemical and biological samples with high sensitivity and without the requirement for labeling of the sample with natural or artificial fluorophores. We experimentally demonstrate a major benefit of this technique, which is the capability to respond exclusively to the linear Raman-resonance properties of the sample, thus allowing a direct quantitative interpretation of image contrast in terms of the number density of Raman-active modes.

  8. Vibrational imaging based on stimulated Raman scattering microscopy

    Science.gov (United States)

    Nandakumar, P.; Kovalev, A.; Volkmer, A.

    2009-03-01

    A stimulated Raman scattering microscope with near-infrared picosecond laser pulses at high repetition rates (76 MHz) and radio-frequency lock-in detection is accomplished. Based on stimulated Raman loss detection, we demonstrate noninvasive point-by-point vibrational mapping of chemical and biological samples with high sensitivity and without the requirement for labeling of the sample with natural or artificial fluorophores. We experimentally demonstrate a major benefit of this technique, which is the capability to respond exclusively to the linear Raman-resonance properties of the sample, thus allowing a direct quantitative interpretation of image contrast in terms of the number density of Raman-active modes.

  9. In situ Raman cell for high pressure and temperature studies of metal and complex hydrides.

    Science.gov (United States)

    Domènech-Ferrer, Roger; Ziegs, Frank; Klod, Sabrina; Lindemann, Inge; Voigtländer, Ralf; Dunsch, Lothar; Gutfleisch, Oliver

    2011-04-15

    A novel cell for in situ Raman studies at hydrogen pressures up to 200 bar and at temperatures as high as 400 °C is presented. This device permits in situ monitoring of the formation and decomposition of chemical structures under high pressure via Raman scattering. The performance of the cell under extreme conditions is stable as the design of this device compensates much of the thermal expansion during heating which avoids defocusing of the laser beam. Several complex and metal hydrides were analyzed to demonstrate the advantageous use of this in situ cell. Temperature calibration was performed by monitoring the structural phase transformation and melting point of LiBH(4). The feasibility of the cell in hydrogen atmosphere was confirmed by in situ studies of the decomposition of NaAlH(4) with added TiCl(3) at different hydrogen pressures and the decomposition and rehydrogenation of MgH(2) and LiNH(2).

  10. Radiative Return Capabilities of a High-Energy, High-Luminosity $e^+e^-$ Collider

    CERN Document Server

    Karliner, Marek; Rosner, Jonathan L; Wang, Lian-Tao

    2015-01-01

    An electron-positron collider operating at a center-of-mass energy $E_{CM}$ can collect events at all lower energies through initial-state radiation (ISR or radiative return). We explore the capabilities for radiative return studies by a proposed high-luminosity collider at $E_{CM}$ = 250 or 90 GeV, to fill in gaps left by lower-energy colliders such as PEP, PETRA, TRISTAN, and LEP. These capabilities are compared with those of the lower-energy $e^+e^-$ colliders as well as hadron colliders such as the Tevatron and the CERN Large Hadron Collider (LHC). Some examples of accessible questions in dark photon searches and heavy flavor spectroscopy are given.

  11. Raman Scattering Spectroscopy of Phase Transition in n-Pentadecane under High Temperature and High Pressure

    Institute of Scientific and Technical Information of China (English)

    QIAO Er-Wei; ZHENG Hai-Fei; XU Bei

    2009-01-01

    The Raman spectroscopy of n-pentadecane is investigated in a moissanite anvil cell at normal temperatures and a diamond anvil cell under pressure to about 3000 MPa and at temperature from 298 to 573 K. Result indicates that at room temperature the vibration modes, assigned to the symmetric and asymmetric stretching of CH3 and CH2 stretching, shift to higher frequency and display a pressure dependent quasi-linear curve. A liquid-solid phase transition appears at a pressure of 150 MPa. The high temperature solidus line of n-pentadecane follows a quadratic function of P = 0.02369T2 - 9.117T + 725.58, in agreement with previous conclusion derived from studies of other hydrocarbons. Upon phase transition, fitting the experimental data obtained in a temperature range of 283-553 K to the Clausius-Clapeyron equation allows one to define the thermodynamic parameters of n-pentadecane of dP/dT = 0.04738T - 9.117.

  12. A Highly Capable Year 6 Student's Response to a Challenging Mathematical Task

    Science.gov (United States)

    Livy, Sharyn; Holmes, Marilyn; Ingram, Naomi; Linsell, Chris; Sullivan, Peter

    2016-01-01

    Highly capable mathematics students are not usually considered strugglers. This paper reports on a case study of a Year 6 student, Debbie, her response to a lesson, and her learning involving a challenging mathematical task. Debbie, usually a highly capable student, struggled to complete a challenging mathematical task by herself, but as the…

  13. Highly sensitive detection of zearalenone in feed samples using competitive surface-enhanced Raman scattering immunoassay.

    Science.gov (United States)

    Liu, Jianzhi; Hu, Yongjun; Zhu, Guichi; Zhou, Xiaoming; Jia, Li; Zhang, Tao

    2014-08-20

    Accurate and quantitative analysis of mycotoxin (such as zearalenone) is particularly imperative in the field of food safety and animal husbandry. Here, we develop a sensitive and specific method for zearalenone detection using competitive surface-enhanced Raman scattering (SERS) immunoassay. In this assay, a functional gold nanoparticle was labeled with the Raman reporter and the zearalenone antibody, and a modified substrate was assembled with the zearalenone-bovine serum albumin. With the addition of free zearalenone, the competitive immune reaction between free zearalenone and zearalenone-bovine serum albumin was initiated for binding with zearalenone antibody labeled on gold nanoparticle, resulting in the change of SERS signal intensity. The proposed method exhibits high sensitivity with a detection limit of 1 pg/mL and a wide dynamic range from 1 to 1000 pg/mL. Furthermore, this method can be further applied to analyze the multiple natural feed samples contaminated with zearalenone, holding great potential for real sample detection.

  14. Stimulated Raman Scattering and Nonlinear Focusing of High-Power Laser Beams Propagating in Water

    CERN Document Server

    Hafizi, B; Penano, J R; Gordon, D F; Jones, T G; Helle, M H; Kaganovich, D

    2015-01-01

    The physical processes associated with propagation of a high-power (power > critical power for self-focusing) laser beam in water include nonlinear focusing, stimulated Raman scattering (SRS), optical breakdown and plasma formation. The interplay between nonlinear focusing and SRS is analyzed for cases where a significant portion of the pump power is channeled into the Stokes wave. Propagation simulations and an analytical model demonstrate that the Stokes wave can re-focus the pump wave after the power in the latter falls below the critical power. It is shown that this novel focusing mechanism is distinct from cross-phase focusing. While discussed here in the context of propagation in water, the gain-focusing phenomenon is general to any medium supporting nonlinear focusing and stimulated forward Raman scattering.

  15. High Efficient C6H12 Raman Laser Enhanced by DCM Fluorescence

    Institute of Scientific and Technical Information of China (English)

    WANG Hong-Bo; LIANG Hui-Min; WANG Zhi-Hua; LUO Shi-Rong; YANG Jing-Guo; ZHENG Wan-Guo; WEI Xiao-Feng; HE Shao-Bo; CHEN Yuan-Bin

    2007-01-01

    @@ We report the first-order Stokes output (wavelength of 627.6 nm) from C6H12 enhanced by DCM dye fluorescence with high energy conversion efficiency of 47.9%, quantum conversion efficiency of 56.5%. To our knowledge, it is the highest conversion efficiency of stimulated Raman scattering obtained from liquid Raman laser. A 532nm frequency doubled Nd:YAG laser with 8Hz repetition rate is employed as the pump source, and the enhancement medium is DCM dye solution in ethanol. The conversion efficiencies at various pump energies and various pump repetition rates are measured and analysed. The enhancement mechanism of SRS together with its potential application is discussed.

  16. High pressure Raman spectroscopic studies of (p−chloroanilinium){sub 2}CuCl{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ghalsasi, Pallavi [School of Engineering and Technology, Navrachana University, Vadodara- 391 410 (India); Garg, Nandini; Sharma, S. M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Center, Mumbai-400 085 (India); Ghalsasi, Prasanna, E-mail: prasanna.ghalsasi@gmail.com; Mande, Hemant, E-mail: prasanna.ghalsasi@gmail.com [Department of Chemistry, The Maharaja Sayajirao Gaikawad University of Baroda, Vadodara - 390 001, Gujarat (India)

    2014-04-24

    (p−chloroanilinium){sub 2}CuCl{sub 4} has a corner shared layered structure of CuCl6{sup 4−} octahedra with p-chloroanilinium cation sandwiched between the layers. The CuCl{sub 6} octahedra are irregular due to Jahn-Teller distortion. We report our high pressure Raman results on this compound in the present manuscript. Our results indicate significant changes in Raman spectra at ∼ 3 GPa and ∼ 8 GPa. The changes at 3 GPa can be attributed to a reduction in puckering of the CuCl{sub 4}{sup 2−} layer and the transition at 8 GPa, which also leads to a colour change of this sample to deep red, could be due to delocalization of the eg electrons along with a reduction of the cooperative Jahn-Teller distortion in this layer. These changes were found to be reversible.

  17. High-pressure measuring cell for Raman spectroscopic studies of natural gas

    DEFF Research Database (Denmark)

    Hansen, Susanne Brunsgaard; Berg, Rolf W.; Stenby, Erling Halfdan

    2001-01-01

    A system for obtaining Raman spectra of gases at high pressure has been constructed. In order to ensure that a natural gas sample is totally representative, a high-pressure gas-measuring cell has been developed, built up by stainless steel fittings and a sapphire tube. The design and construction...... of this cell are described. A perfect pressure seal has been demonstrated up to 15.0 MPaA (MPa absolute). The cell has been successfully used to obtain Raman spectra of natural gas samples. Some of these spectra are presented and assigned. The most remarkable observation in the spectra is that it is possible...... to detect hydrogen sulfide at concentrations of 1-3 mg H2S/Nm(3). An attempt to make a quantitative analysis of natural gas by the so-called "ratio method" is presented. In addition to this, the relative normalized differential Raman scattering cross sections for ethane and i-butane molecules at 8.0 MPa...

  18. In-situ Raman spectroscopy and high-speed photography of a shocked triaminotrinitrobenzene based explosive

    Science.gov (United States)

    Saint-Amans, C.; Hébert, P.; Doucet, M.; de Resseguier, T.

    2015-01-01

    We have developed a single-shot Raman spectroscopy experiment to study at the molecular level the initiation mechanisms that can lead to sustained detonation of a triaminotrinitrobenzene-based explosive. Shocks up to 30 GPa were generated using a two-stage laser-driven flyer plate generator. The samples were confined by an optical window and shock pressure was maintained for at least 30 ns. Photon Doppler Velocimetry measurements were performed at the explosive/window interface to determine the shock pressure profile. Raman spectra were recorded as a function of shock pressure and the shifts of the principal modes were compared to static high-pressure measurements performed in a diamond anvil cell. Our shock data indicate the role of temperature effects. Our Raman spectra also show a progressive extinction of the signal which disappears around 9 GPa. High-speed photography images reveal a simultaneous progressive darkening of the sample surface up to total opacity at 9 GPa. Reflectivity measurements under shock compression show that this opacity is due to a broadening of the absorption spectrum over the entire visible region.

  19. Study of Raman spectroscopic analysis method for sodium compounds at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Fumiyoshi; Ohtori, Norikazu [Japan Nuclear Cycle Development Inst., Oarai, Ibaraki (Japan). Oarai Engineering Center

    2002-09-01

    High-temperature sodium on exposure to air produces a corrosive melt including Na{sub 2}O, Na{sub 2}O{sub 2} and NaOH after reaction with oxygen and moisture. If the melt contacts steel, several sodium-iron complex oxides will be produced by the corrosion reaction. To contribute to elucidation of the corrosion mechanism, the Raman spectroscopic technique for analysis of strongly corrosive sodium compounds was developed and the behavior of corrosive chemical species in the compounds was investigated. Several Raman spectra of a series of typical sodium compounds such as Na{sub 2}O{sub 2} were measured in the range from room temperature to 1,073K. Subsequently, a simulated corrosive mixture of molten sodium hydroxide with peroxide was investigated, and peroxide ion was detected up to 823K. Thus, peroxide ion can be a corrosive chemical species in the melt at high temperature. Moreover, Raman spectra obtained for several sodium-iron complex oxides, e.g. Na{sub 4}FeO{sub 3}, indicate that each oxide can be identified up to 573K. (author)

  20. Ultra-low frequency Raman spectroscopy of SWNTs under high pressure

    Science.gov (United States)

    Shen, Y.; Quirke, N.; Zerulla, D.

    2016-09-01

    Radial deformation phenomena of carbon nanotubes (CNTs) are attracting increased attention because even minimal changes of the CNT's cross section can result in significant changes of their electronic and optical properties. It is therefore important to have the ability to sensitively probe and characterize this radial deformation. High pressure Raman spectroscopy offers a general and powerful method to study such effects in SWNTs. In this experimental work, we focus in particular on one theoretically predicted Raman vibrational mode, the so-called "Squash Mode" (SM), named after its vibrational mode pattern, which has an E2g symmetry representation and exists at shifts below the radial breathing mode (RBM) region. The Squash mode was predicted to be more sensitive to environmental changes than the RBM. Here we report on a detailed, experimental detection of SMs of aligned SWNT arrays with peaks as close as 18 cm-1 to the laser excitation energy. Furthermore, we investigate how the SM of aligned CNT arrays reacts when exposed to a high pressure environment of up to 9 GPa. The results confirm the theoretical predictions regarding the angular and polarization dependent variations of the SM's intensity with respect to their excitation. Furthermore, clear Raman upshifts of SM under pressures of up to 9 GPa are presented. The relative changes of these upshifts, and hence the sensitivity, are much higher than that of RBMs because of larger radial displacement of some of the participating carbon atoms during the SM vibration. These novel ultra-sensitive Raman SM shifts of SWNTs provide enhanced sensitivity and demonstrate new opportunities for nano-optical sensors applications.

  1. Survey of industrial coal conversion equipment capabilities: high-temperature, high-pressure gas purification

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, J. P.; Edwards, M. S.

    1978-06-01

    In order to ensure optimum operating efficiencies for combined-cycle electric generating systems, it is necessary to provide gas treatment equipment capable of operating at high temperatures (>1000/sup 0/F) and high pressure (>10 atmospheres absolute). This equipment, when assembled in a process train, will be required to condition the inlet stream to a gas turbine to suitable levels of gas purity (removal of particulate matter, sulfur, nitrogen, and alkali metal compounds) so that it will be compatible with both environmental and machine constraints. In this work, a survey of the available and developmental equipment for the removal of particulate matter and sulfur compounds has been conducted. In addition, an analysis has been performed to evaluate the performance of a number of alternative process configurations in light of overall system needs. Results from this study indicate that commercially available, reliable, and economically competitive hot-gas cleanup equipment capable of conditioning raw product gas to the levels required for high-temperatue turbine operation will not be available for some time.

  2. Fluorescence and Raman spectra on surface of K9 glass by high fluence ultraviolet laser irradiation at 355 nm

    Science.gov (United States)

    Zhang, Zhen; Huang, Jin; Geng, Feng; Zhou, Xiaoyan; Feng, Shiquan; Ren, Dahua; Cheng, Xinlu; Jiang, Xiaodong; Wu, Weidong; Zheng, Wanguo; Tang, Yongjian

    2013-11-01

    In order to explore the damage mechanisms of K9 glass irradiated by high energy density ultraviolet laser, laser-induced fluorescence and Raman spectra were investigated. Compared the fluorescence spectra of damaged area, undamaged area and sub-damaged area, it can be conclude that the fluorescence spectrum of sub-damaged area is different from the structure of the other two areas. Especially, the main peak of the spectra at 415 nm reveals the unique characteristics of K9 glass. The structure at the sub-damaged area enhances intensity of the Raman scattering spectra. Three peaks of the spectra at about 500 nm and two characteristic peaks at about 550 nm exhibit the characterization of damaged area. A peak of the Raman scattering spectra at 350 nm which related to water can be observed. The relationship between intensity of Raman scattering and laser intensity at 355 nm is investigated by confocal Raman microscopy. At sub-damage area, signal of Raman scattering is rather high and decreased dramatically with respect to energy density. The major band at about 1470 cm-1 sharpened and moved to higher frequency with densification. These phenomena demonstrate that the structure of sub-damaged area has some characterization compared with the damaged area. The investigation of defect induced fluorescence and Raman spectra on surface of K9 glass is important to explore the damage mechanisms of optical materials irradiated by ultraviolet laser irradiation at 355 nm.

  3. A New High-Speed, High-Cycle, Gear-Tooth Bending Fatigue Test Capability

    Science.gov (United States)

    Stringer, David B.; Dykas, Brian D.; LaBerge, Kelsen E.; Zakrajsek, Andrew J.; Handschuh, Robert F.

    2011-01-01

    A new high-speed test capability for determining the high cycle bending-fatigue characteristics of gear teeth has been developed. Experiments were performed in the test facility using a standard spur gear test specimens designed for use in NASA Glenn s drive system test facilities. These tests varied in load condition and cycle-rate. The cycle-rate varied from 50 to 1000 Hz. The loads varied from high-stress, low-cycle loads to near infinite life conditions. Over 100 tests were conducted using AISI 9310 steel spur gear specimen. These results were then compared to previous data in the literature for correlation. Additionally, a cycle-rate sensitivity analysis was conducted by grouping the results according to cycle-rate and comparing the data sets. Methods used to study and verify load-path and facility dynamics are also discussed.

  4. Fast spectral coherent anti-Stokes Raman scattering microscopy with high-speed tunable picosecond laser.

    Science.gov (United States)

    Cahyadi, Harsono; Iwatsuka, Junichi; Minamikawa, Takeo; Niioka, Hirohiko; Araki, Tsutomu; Hashimoto, Mamoru

    2013-09-01

    We develop a coherent anti-Stokes Raman scattering (CARS) microscopy system equipped with a tunable picosecond laser for high-speed wavelength scanning. An acousto-optic tunable filter (AOTF) is integrated in the laser cavity to enable wavelength scanning by varying the radio frequency waves applied to the AOTF crystal. An end mirror attached on a piezoelectric actuator and a pair of parallel plates driven by galvanometer motors are also introduced into the cavity to compensate for changes in the cavity length during wavelength scanning to allow synchronization with another picosecond laser. We demonstrate fast spectral imaging of 3T3-L1 adipocytes every 5  cm-1 in the Raman spectral region around 2850  cm-1 with an image acquisition time of 120 ms. We also demonstrate fast switching of Raman shifts between 2100 and 2850  cm-1, corresponding to CD2 symmetric stretching and CH2 symmetric stretching vibrations, respectively. The fast-switching CARS images reveal different locations of recrystallized deuterated and nondeuterated stearic acid.

  5. High wavenumber Raman spectroscopic characterization of normal and oral cancer using blood plasma

    Science.gov (United States)

    Pachaiappan, Rekha; Prakasarao, Aruna; Suresh Kumar, Murugesan; Singaravelu, Ganesan

    2017-02-01

    Blood plasma possesses the biomolecules released from cells/tissues after metabolism and reflects the pathological conditions of the subjects. The analysis of biofluids for disease diagnosis becomes very attractive in the diagnosis of cancers due to the ease in the collection of samples, easy to transport, multiple sampling for regular screening of the disease and being less invasive to the patients. Hence, the intention of this study was to apply near-infrared (NIR) Raman spectroscopy in the high wavenumber (HW) region (2500-3400 cm-1) for the diagnosis of oral malignancy using blood plasma. From the Raman spectra it is observed that the biomolecules protein and lipid played a major role in the discrimination between groups. The diagnostic algorithms based on principal components analysis coupled with linear discriminant analysis (PCA-LDA) with the leave-one-patient-out cross-validation method on HW Raman spectra yielded a promising results in the identification of oral malignancy. The details of results will be discussed.

  6. The molecular interaction of a protein in highly concentrated solution investigated by Raman spectroscopy.

    Science.gov (United States)

    Ota, Chikashi; Noguchi, Shintaro; Tsumoto, Kouhei

    2015-04-01

    We used Raman spectroscopy to investigate the structure and interactions of lysozyme molecules in solution over a wide range of concentrations (2.5-300 mg ml(-1)). No changes in the amide-I band were observed as the concentration was increased, but the width of the Trp band at 1555 cm(-1) and the ratios of the intensities of the Tyr bands at 856 and 837 cm(-1), the Trp bands at 870 and 877 cm(-1), and the bands at 2940 (CH stretching) and 3420 cm(-1) (OH stretching) changed as the concentration was changed. These results reveal that although the distance between lysozyme molecules changed by more than an order of magnitude over the tested concentration range, the secondary structure of the protein did not change. The changes in the molecular interactions occurred in a stepwise process as the order of magnitude of the distance between molecules changed. These results suggest that Raman bands can be used as markers to investigate the behavior of high-concentration solutions of proteins and that the use of Raman spectroscopy will lead to progress in our understanding not only of the basic science of protein behavior under concentrated (i.e., crowded) conditions but also of practical processes involving proteins, such as in the field of biopharmaceuticals. © 2014 Wiley Periodicals, Inc.

  7. Integration of a nanostructured dielectrophoretic device and a surface-enhanced Raman probe for highly sensitive rapid bacteria detection.

    Science.gov (United States)

    Madiyar, Foram Ranjeet; Bhana, Saheel; Swisher, Luxi Z; Culbertson, Christopher T; Huang, Xiaohua; Li, Jun

    2015-02-28

    This work reports a synergistic approach to the concentration, detection and kinetic monitoring of pathogens through the integration of nanostructured dielectrophoresis (DEP) with nanotag-labelled Surface Enhanced Raman Spectroscopy (SERS). A nanoelectrode array made of embedded Vertically Aligned Carbon Nanofibers (VACNFs) at the bottom of a microfluidic chip was used to effectively capture and concentrate nanotag-labelled E. coli DHα5 cells into a 200 μm × 200 μm area on which a Raman laser probe was focused. The SERS nanotags were based on iron oxide-gold (IO-Au) core-shell nanoovals (NOVs) of ∼50 nm size, which were coated with a QSY21 Raman reporter and attached to E. coli through specific immunochemistry. The combination of the greatly enhanced Raman signal by the SERS nanotags and the effective DEP concentration significantly improved the detection limit and speed. The SERS signal was measured with both a confocal Raman microscope and a portable Raman probe during DEP capture, and was fully validated with fluorescence microscopy measurements under all DEP conditions. The SERS measurements were sensitive enough to detect a single bacterium. A concentration detection limit as low as 210 cfu ml(-1) using a portable Raman system was obtained with a DEP capture time of only ∼50 s. These results demonstrate the potential to develop a compact portable system for rapid and highly sensitive detection of specific pathogens. This system is reusable, requires minimum sample preparation, and is amenable to field applications.

  8. UV Raman imaging--a promising tool for astrobiology: comparative Raman studies with different excitation wavelengths on SNC Martian meteorites.

    Science.gov (United States)

    Frosch, Torsten; Tarcea, Nicolae; Schmitt, Michael; Thiele, Hans; Langenhorst, Falko; Popp, Jürgen

    2007-02-01

    The great capabilities of UV Raman imaging have been demonstrated on the three Martian meteorites: Sayh al Uhaymir, Dar al Gani, and Zagami. Raman spectra without disturbing fluorescence and with high signal-to-noise-ratios and full of spectral features were derived. This result is of utmost importance for the development of powerful instruments for space missions. By point scanning the surfaces of the meteorite samples, it was possible for the first time to construct UV-Raman images out of the array of Raman spectra. Deep-UV Raman images are to the best of our knowledge presented for the first time. The images were used for a discussion of the chemical-mineralogical composition and texture of the meteorite surfaces. Comparative Raman studies applying visible and NIR Raman excitation wavelengths demonstrate a much better performance for UV Raman excitation. This comparative study of different Raman excitation wavelengths at the same sample spots was done by constructing a versatile, robust sample holder with a fixed micro-raster. The overall advantages of UV resonance Raman spectroscopy in terms of sensitivity and selectivity are demonstrated and discussed. Finally the application of this new technique for a UV Raman instrument for envisaged astrobiological focused space missions is suggested.

  9. Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 GPa

    Directory of Open Access Journals (Sweden)

    JianJun Jiang

    2016-03-01

    Full Text Available The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC, to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E 2 g 1 ,A1g, and 2LA(M. Over our experimental temperature and pressure range (300–600 K and 1 atm−18.5 GPa, the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3–4 GPa lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.

  10. A facile precursor route to highly loaded metal/ceramic nanofibers as a robust surface-enhanced Raman template

    Science.gov (United States)

    Park, Jay Hoon; Joo, Yong Lak

    2017-09-01

    We report silver (Ag)/ceramic nanofibers with highly robust and sensitive optical sensory capabilities that can withstand harsh conditions. These nanofibers are fabricated by first electrospinning solutions of poly vinyl alcohol (PVA) and metal precursor polymers, followed by subsequent series of heat treatment. The reported fabrication method demonstrate the effects of (i) the location of Ag crystals, (ii) crystal size and shape, and (iii) constituents of the ceramic matrix as surface-enhanced Raman spectroscopy (SERS) templates with 10-6 M 4-mercaptobenzoic acid (4-MBA). Notably, these silver/ceramic nanofibers preserved most of their highly sensitive localized surface plasmon resonance (LSPR) even under high temperature of 400 °C, in contrast to preformed Ag nanoparticles (NPs) in PVA nanofibers which lost most of its optical property presumably due to (i) Ag oxidation and (ii) loss of the matrix material. Among the ceramic substrates of ZrO2, Al2O3, and ZnO with silver crystals, we discovered that the ZnO substrate showed the most consistent and the strongest signal strength owing to the synergistic chemical and optical properties of the ZnO substrate. Moreover, the pure Ag nanofiber proved to be the best heat-resistant SERS template, owing to its (i) anisotropic morphology and (ii) thicker diameter when compared with other conventional Ag nanomaterials. These results demonstrated simple yet highly controllable fabrication of robust SERS templates, with potential applications in a catalytic sensory which is often exposed to harsh conditions.

  11. Raman-strain relations in highly strained Ge: Uniaxial ⟨100⟩, ⟨110⟩ and biaxial (001) stress

    Science.gov (United States)

    Gassenq, A.; Tardif, S.; Guilloy, K.; Duchemin, I.; Pauc, N.; Hartmann, J. M.; Rouchon, D.; Widiez, J.; Niquet, Y. M.; Milord, L.; Zabel, T.; Sigg, H.; Faist, J.; Chelnokov, A.; Rieutord, F.; Reboud, V.; Calvo, V.

    2017-02-01

    The application of high values of strain to Ge considerably improves its light emission properties and can even turn it into a direct band gap semiconductor. Raman spectroscopy is routinely used for strain measurements. Typical Raman-strain relationships that are used for Ge were defined up to ˜1% strain using phonon deformation potential theory. In this work, we have studied this relationship at higher strain levels by calculating and measuring the Raman spectral shift-strain relations in several different strain configurations. Since differences were shown between the usual phonon deformation potential theory and ab-initio calculations, we highlight the need for experimental calibrations. We have then measured the strain in highly strained Ge micro-bridges and micro-crosses using Raman spectroscopy performed in tandem with synchrotron based micro-diffraction. High values of strain are reported, which enable the calibration of the Raman-strain relations up to 1.8% of in plane strain for the (001) biaxial stress, 4.8% strain along ⟨100⟩, and 3.8% strain along ⟨110⟩. For Ge micro-bridges, oriented along ⟨100⟩, the nonlinearity of the Raman shift-strain relation is confirmed. For the ⟨110⟩ orientation, we have shown that an unexpected non-linearity in the Raman-strain relationship has also to be taken into account for high stress induction. This work demonstrates an unprecedented level of strain measurement for the ⟨110⟩ uniaxial stress and gives a better understanding of the Raman-strain relations in Ge.

  12. High vacuum tip-enhanced Raman spectroscope based on a scanning tunneling microscope

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yurui [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); Bionanophotonics, Department of Applied Physics, Chalmers University of Technology, Göteborg, SE 41296 (Sweden); Zhang, Zhenglong [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China); School of Physics and Information Technology, Shaanxi Normal University, 710062 Xi’an (China); Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena (Germany); Sun, Mengtao, E-mail: mtsun@iphy.ac.cn [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P. O. Box 603-146, Beijing 100190 (China)

    2016-03-15

    In this paper, we present the construction of a high-vacuum tip-enhanced Raman spectroscopy (HV-TERS) system that allows in situ sample preparation and measurement. A detailed description of the prototype instrument is presented with experimental validation of its use and novel ex situ experimental results using the HV-TERS system. The HV-TERS system includes three chambers held under a 10{sup −7} Pa vacuum. The three chambers are an analysis chamber, a sample preparation chamber, and a fast loading chamber. The analysis chamber is the core chamber and contains a scanning tunneling microscope (STM) and a Raman detector coupled with a 50 × 0.5 numerical aperture objective. The sample preparation chamber is used to produce single-crystalline metal and sub-monolayer molecular films by molecular beam epitaxy. The fast loading chamber allows ex situ preparation of samples for HV-TERS analysis. Atomic resolution can be achieved by the STM on highly ordered pyrolytic graphite. We demonstrate the measurement of localized temperature using the Stokes and anti-Stokes TERS signals from a monolayer of 1,2-benzenedithiol on a gold film using a gold tip. Additionally, plasmonic catalysis can be monitored label-free at the nanoscale using our device. Moreover, the HV-TERS experiments show simultaneously activated infrared and Raman vibrational modes, Fermi resonance, and some other non-linear effects that are not observed in atmospheric TERS experiments. The high spatial and spectral resolution and pure environment of high vacuum are beneficial for basic surface studies.

  13. Highly Capable Micropump-fed Propulsion System for Proximity Operations, Landing and Ascent Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Flight Works is proposing to expand its work in micro-gear-pumps for propulsion applications in order to provide a highly capable propulsion and attitude control...

  14. Strategic alliances and product development in high technology new firms: The moderating effect of technological capabilities

    NARCIS (Netherlands)

    Haeussler, C.; Patzelt, H.; Zahra, Shaker

    2012-01-01

    High technology new firms have extensively used strategic alliances to gain access to knowledge, resources and capabilities. However, given their inexperience and limited resources, these firms are vulnerable to their more established partners' potential opportunism. This raises the question: How

  15. High Resolution Analysis of Selected Organic Compounds in Icy Terrains, Using Surface-enhanced Raman Spectroscopy

    Science.gov (United States)

    Parnell, J.; Bowden, S. A.; Phillips, S. J.; Wilson, R.; Cooper, J. M.

    2008-03-01

    Surface-enhanced Raman spectroscopy will increase sensitivity by several orders of magnitude over conventional Raman, and should be considered for future missions. We demonstrate detection of organic pigments from ice containing snow algae.

  16. Nanoporous gold as a highly active substrate for surface-enhanced Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kucheyev, S O; Hayes, J R; Biener, J; Hamza, A V

    2006-03-28

    Colloidal solutions of metal nanoparticles are currently among most studied substrates for sensors based on surface-enhanced Raman scattering (SERS). However, such substrates often suffer from not being cost-effective, reusable, or stable. Here, we develop nanoporous Au as a highly active, tunable, a.ordable, stable, bio-compatible, and reusable SERS substrate. Nanoporous Au is prepared by a facile process of free corrosion of AgAu alloys followed by annealing. Results show that nanofoams with average pore sizes of {approx} 250 nm exhibit the largest SERS signal for 632.8 nm excitation. This is attributed to the electromagnetic SERS enhancement mechanism with additional field localization within pores.

  17. Stimulated Raman scattering modes in highly elliptical-core optical fiber

    Institute of Scientific and Technical Information of China (English)

    王兆民; 顾春明; 林景全; 郑学彦

    1996-01-01

    Stimulated Raman scattering (SRS) transmission modes in highly elliptical-core optical fiber of three different structures are experimentally researched.The measuring setup,SRS spectrum and photographs of Stokes modes are given.The observed phenomena are completely different from those on circular-core graded-index optical fiber.The beam sizes of SRS remain constant and SRS light transmits with the characteristics of higher-order.mode.In addition,the experimental results are theoretically explained with fiber-optical dispersion theory and SRS phase matching conditions.Experimental results and theoretical analyses are in good agreement.

  18. High temperature measurements in irradiated environment using Raman fiber optics distributed temperature sensing

    Science.gov (United States)

    Lecomte, Pierre; Blairon, Sylvain; Boldo, Didier; Taillade, Frédéric; Caussanel, Matthieu; Beauvois, Gwendal; Duval, Hervé; Grieu, Stéphane; Laffont, Guillaume; Lainé, Frédéric; Carrel, Frédéric

    2016-04-01

    Optical fiber temperature sensors using Raman effect are a promising technology for temperature mapping of nuclear power plant pipes. These pipes are exposed to high temperature (350 °C) and gamma radiations, which is a harsh environment for standard telecom fibers. Therefore metal coated fibers are to be used to perform measurement over 300 °C. Temperature variations can affect the attenuation of the metallic coated fiber before irradiation. The latter induces an extra attenuation, due to light absorption along the fiber by radiation-induced defects. The recombination of these defects can be strongly accelerated by the high temperature value. As backscattered Raman signal is weak it is important to test optical fibers under irradiation to observe how it gets attenuated. Different experiments are described in this conference paper: two in situ irradiation campaigns with different dose rates at, both ambient and high temperature. We observe that the tested off-the-shelf metallic coated fibers have a high attenuation under irradiation. We also noticed the fact that thermal annealing plays a massive role in the +300 °C temperature range.

  19. A Compact, High Power Capable, and Tunable High Directivity Microstrip Coupler.

    Science.gov (United States)

    Sohn, Sung-Min; Gopinath, Anand; Vaughan, John Thomas

    2016-10-01

    A coupler is an indispensable component to sample the forward and reflected power for the real-time radio frequency (RF) power monitoring system. The directivity of a coupler is a critical factor to achieve accurate RF power measurements. This paper proposes a microstrip coupler with a tunable high directivity circuit to accurately measure the reflected RF power. The directivity tuner composed of passive components adjusts phase and amplitude of the coupled RF signal, and cancel out the leakage signal from the RF input port at the coupled reflection port. The experimental results, which agree with simulation results, show that the microstrip coupler with the directivity tuner circuit has a compact size (~ 0.07 λg x 0.05 λg), high power capability (up to 1 kW), and high directivities (more than 40 dB) at operating frequency bands (f = 297.3 MHz, 400 MHz, and 447 MHz, respectively) for magnetic resonance imaging (MRI) applications.

  20. Identification of metalloporphyrins with high sensitivity using graphene-enhanced resonance Raman scattering.

    Science.gov (United States)

    Kim, Bo-Hyun; Kim, Daechul; Song, Sungho; Park, DongHyuk; Kang, Il-Suk; Jeong, Dae Hong; Jeon, Seokwoo

    2014-03-18

    Graphene-enhanced resonance Raman scattering (GERRS) was performed for the detection of three different metallo-octaethylporphyrins (M-OEPs; M = 2H, FeCl, and Pt) homogeneously thermal vapor deposited on a graphene surface. GERRS of M-OEPs were measured using three different excitation wavelengths, λ(ex) = 405, 532, and 633 nm, and characterized detail vibrational bands for the identification of M-OEPs. The GERRS spectra of Pt-OEP at λ(ex) = 532 nm showed ~29 and ~162 times signal enhancement ratio on graphene and on graphene with Ag nanoclusters, respectively, compared to the spectra from bare SiO2 substrate. This enhancement ratio, however, was varied with M-OEPs and excitation wavelengths. The characteristic peaks and band shapes of GERRS for each M-OEP were measured with high sensitivity (100 pmol of thermal vapor deposited Pt-OEP), and these facilitate the selectively recognition of molecules. Also, the peaks shift and broadening provide the evidence of the interaction between graphene and M-OEPs through the charge transfer and π-orbital interaction. The increase of graphene layer induced the decrease of signal intensity and GERRS effect was almost not observed on the thick graphite flakes. Further experiments with various substrates demonstrated that the interaction of single layer of graphene with molecule is the origin of the Raman signal enhancement of M-OEPs. In this experiment, we proved the graphene is a good alternative substrate of Raman spectroscopy for the selective detection of various metalloporphyrins with high sensitivity.

  1. Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures

    Science.gov (United States)

    Hattrick-Simpers, Jason R.; Hurst, Wilbur S.; Srinivasan, Sesha S.; Maslar, James E.

    2011-03-01

    An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH4)2 and nano-LiBH4-LiNH2-MgH2 hydrogen storage systems at elevated temperatures and pressures are reported.

  2. Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures.

    Science.gov (United States)

    Hattrick-Simpers, Jason R; Hurst, Wilbur S; Srinivasan, Sesha S; Maslar, James E

    2011-03-01

    An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH(4))(2) and nano-LiBH(4)-LiNH(2)-MgH(2) hydrogen storage systems at elevated temperatures and pressures are reported.

  3. Monitoring of Spectral Map Changes from Normal State to Superconducting State in High-TC Superconductor Films Using Raman Imaging

    Directory of Open Access Journals (Sweden)

    J. L. González-Solís

    2015-01-01

    Full Text Available We have explored the chemical structure of TlBa2Ca2Cu3O9 high-TC superconductor films with Tl-1223 phase to monitor spectral map changes from normal state to superconducting state using the technique of Raman imaging. Raman images were performed for 12 different temperatures in the 77–293 K range. At room temperature, the Raman images were characterized by a single color but as the temperature dropped a new color appeared and when the temperature of 77 K is reached and the superconducting state is assured, the Raman images were characterized by the red, green, and blue colors. Our study could suggest that the superconducting state emerged around 133 K, in full agreement with those reported in the literature. A cross-checking was done applying principal component analysis (PCA to other sets of Raman spectra of our films measured at different temperatures. PCA result showed that the spectra can be grouped into two temperature ranges, one in the 293–153 K range and the other in the 133–77 K range suggesting that transition to the superconducting state occurred at some temperature around 133 K. This is the first report of preliminary results evaluating the usefulness of Raman imaging in determination of transition temperature of superconductor films.

  4. Raman and photoelectron spectroscopic investigation of high-purity niobium materials: Oxides, hydrides, and hydrocarbons

    Science.gov (United States)

    Singh, Nageshwar; Deo, M. N.; Nand, Mangla; Jha, S. N.; Roy, S. B.

    2016-09-01

    We present investigations of the presence of oxides, hydrides, and hydrocarbons in high-purity (residual resistivity ratio, ˜300) niobium (Nb) materials used in fabrication of superconducting radio frequency (SRF) cavities for particle accelerators. Raman spectroscopy of Nb materials (as-received from the vendor as well as after surface chemical- and thermal processing) revealed numerous peaks, which evidently show the presence of oxides (550 cm-1), hydrides (1277 and 1385 cm-1: ˜80 K temperature), and groups of hydrocarbons (1096, 2330, 2710, 2830, 2868, and 3080 cm-1). The present work provides direct spectroscopic evidence of hydrides in the electropolished Nb materials typically used in SRF cavities. Raman spectroscopy thus can provide vital information about the near-surface chemical species in niobium materials and will help in identifying the cause for the performance degradation of SRF cavities. Furthermore, photoelectron spectroscopy was performed on the Nb samples to complement the Raman spectroscopy study. This study reveals the presence of C and O in the Nb samples. Core level spectra of Nb (doublet 3d5/2 and 3d3/2) show peaks near 206.6 and 209.4 eV, which can be attributed to the Nb5+ oxidation state. The core level spectra of C 1 s of the samples are dominated by graphitic carbon (binding energy, 284.6 eV), while the spectra of O 1 s are asymmetrically peaked near binding energy of ˜529 eV, and that indicates the presence of metal-oxide Nb2O5. The valence-band spectra of the Nb samples are dominated by a broad peak similar to O 2p states, but after sputtering (for 10 min) a peak appears at ˜1 eV, which is a feature of the elemental Nb atom.

  5. Raman spectroscopy for highly accurate estimation of the age of refrigerated porcine muscle

    Science.gov (United States)

    Timinis, Constantinos; Pitris, Costas

    2016-03-01

    The high water content of meat, combined with all the nutrients it contains, make it vulnerable to spoilage at all stages of production and storage even when refrigerated at 5 °C. A non-destructive and in situ tool for meat sample testing, which could provide an accurate indication of the storage time of meat, would be very useful for the control of meat quality as well as for consumer safety. The proposed solution is based on Raman spectroscopy which is non-invasive and can be applied in situ. For the purposes of this project, 42 meat samples from 14 animals were obtained and three Raman spectra per sample were collected every two days for two weeks. The spectra were subsequently processed and the sample age was calculated using a set of linear differential equations. In addition, the samples were classified in categories corresponding to the age in 2-day steps (i.e., 0, 2, 4, 6, 8, 10, 12 or 14 days old), using linear discriminant analysis and cross-validation. Contrary to other studies, where the samples were simply grouped into two categories (higher or lower quality, suitable or unsuitable for human consumption, etc.), in this study, the age was predicted with a mean error of ~ 1 day (20%) or classified, in 2-day steps, with 100% accuracy. Although Raman spectroscopy has been used in the past for the analysis of meat samples, the proposed methodology has resulted in a prediction of the sample age far more accurately than any report in the literature.

  6. Raman-free nonlinear optical effects in high pressure gas-filled hollow core PCF.

    Science.gov (United States)

    Azhar, M; Wong, G K L; Chang, W; Joly, N Y; Russell, P St J

    2013-02-25

    The effective Kerr nonlinearity of hollow-core kagomé-style photonic crystal fiber (PCF) filled with argon gas increases to ~15% of that of bulk silica glass when the pressure is increased from 1 to 150 bar, while the zero dispersion wavelength shifts from 300 to 900 nm. The group velocity dispersion of the system is uniquely pressure-tunable over a wide range while avoiding Raman scattering-absent in noble gases-and having an extremely high optical damage threshold. As a result, detailed and well-controlled studies of nonlinear effects can be performed, in both normal and anomalous dispersion regimes, using only a fixed-frequency pump laser. For example, the absence of Raman scattering permits clean observation, at high powers, of the interaction between a modulational instability side-band and a soliton-created dispersive wave. Excellent agreement is obtained between numerical simulations and experimental results. The system has great potential for the realization of reconfigurable supercontinuum sources, wavelength convertors and short-pulse laser systems.

  7. Large High Performance Optics for Spaceborne Missions: L-3 Brashear Experience and Capability

    Science.gov (United States)

    Canzian, Blaise; Gardopee, George; Clarkson, Andrew; Hull, Tony; Borucki, William J.

    2010-01-01

    Brashear is a division of L-3 Communications, Integrated Optical Systems. Brashear is well known for the ground-based telescopes it has manufactured at its facilities and delivered to satisfied customers. Optics from meter-class up to 8.3 meters diameter have been fabricated in Brashear's facilities. Brashear has demonstrated capabilities for large spaceborne optics. We describe in this paper both legacy and new Brashear capabilities for high performance spaceborne optics.

  8. Fabrication of gold nanoparticle-embedded metal-organic framework for highly sensitive surface-enhanced Raman scattering detection.

    Science.gov (United States)

    Hu, Yuling; Liao, Jia; Wang, Dongmei; Li, Gongke

    2014-04-15

    Surface-enhanced Raman scattering (SERS) signals strongly rely on the interactions and distance between analyte molecules and metallic nanostructures. In this work, the use of a gold nanoparticle (AuNP)-embedded metal-organic framework was introduced for the highly sensitive SERS detection. The AuNPs were in situ grown and encapsulated within the host matrix of MIL-101 by a solution impregnation strategy. The as-synthesized AuNPs/MIL-101 nanocomposites combined the localized surface plasmon resonance properties of the gold nanoparticles and the high adsorption capability of metal-organic framework, making them highly sensitive SERS substrates by effectively preconcentrating analytes in close proximity to the electromagnetic fields at the SERS-active metal surface. We discussed the fabrication, physical characterization, and SERS activity of our novel substrates by measuring the Raman signals of a variety of model analytes. The SERS substrate was found to be highly sensitive, robust, and amiable to several different target analytes. A SERS detection limit of 41.75 and 0.54 fmol for Rhodamine 6G and benzadine, respectively, was demonstrated. The substrate also showed high stability and reproducibility, as well as molecular sieving effect thanks to the protective shell of the metal-organic framework. Subsequently, the potential practical application of the novel SERS substrate was evaluated by quantitative analysis of organic pollutant p-phenylenediamine in environmental water and tumor marker alpha-fetoprotein in human serum. The method showed good linearity between 1.0 and 100.0 ng/mL for p-phenylenediamine and 1.0-130.0 ng/mL for alpha-fetoprotein with the correlation coefficients of 0.9950 and -0.9938, respectively. The recoveries ranged from 80.5% to 114.7% for p-phenylenediamine in environmental water and 79.3% to 107.3% for alpha-fetoprotein in human serum. These results foresee promising application of the novel metal-organic framework based composites as

  9. A CMOS image sensor using high-speed lock-in pixels for stimulated Raman scattering

    Science.gov (United States)

    Lioe, DeXing; Mars, Kamel; Takasawa, Taishi; Yasutomi, Keita; Kagawa, Keiichiro; Hashimoto, Mamoru; Kawahito, Shoji

    2016-03-01

    A CMOS image sensor using high-speed lock-in pixels for stimulated Raman scattering (SRS) spectroscopy is presented in this paper. The effective SRS signal from the stimulated emission of SRS mechanism is very small in contrast to the offset of a probing laser source, which is in the ratio of 10-4 to 10-5. In order to extract this signal, the common offset component is removed, and the small difference component is sampled using switched-capacitor integrator with a fully differential amplifier. The sampling is performed over many integration cycles to achieve appropriate amplification. The lock-in pixels utilizes high-speed lateral electric field charge modulator (LEFM) to demodulate the SRS signal which is modulated at high-frequency of 20MHz. A prototype chip is implemented using 0.11μm CMOS image sensor technology.

  10. Pulsed laser deposited Ag nanoparticles on nickel hydroxide nanosheet arrays for highly sensitive surface-enhanced Raman scattering spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Yuting; Wang, Huanwen; Chen, Xiao [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn [Department of Chemistry, Tongji University, Shanghai 200092 (China); Wei, Huige [Integrated Composites Laboratory (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States); Guo, Zhanhu, E-mail: zhanhu.guo@lamar.edu [Integrated Composites Laboratory (ICL), Dan F. Smith Department of Chemical Engineering, Lamar University, Beaumont, Texas 77710 (United States)

    2014-10-15

    Highlights: • Silver nanoparticles (NPs) were deposited on nickel hydroxide nanosheet (NS) arrays by pulsed laser deposition (PLD) for surface-enhanced Raman scattering (SERS) spectroscopy. • The Ag/Ni(OH){sub 2} composite film exhibits very high Raman scattering enhancement ability, possessing an enhancement factor as high as 5 × 10{sup 6}. • The enhancement ability of the substrate was strongly dependent on the size and interparticle gap of Ag NPs. • The 3D structure of Ni(OH){sub 2} NS arrays and the charge transfer of Ag NPs may be responsible for this high sensitivity Raman phenomenon. - Abstract: In the present work, silver nanoparticles (NPs) were deposited on nickel hydroxide nanosheet (NS) arrays by pulsed laser deposition (PLD) for surface-enhanced Raman scattering (SERS) spectroscopy. The effective high specific surface area with silver NPs decorated on the NS arrays was revealed by field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The microstructure and optical property of this three-dimensional (3D) substrate were investigated by X-ray diffraction (XRD) and UV–vis spectra, respectively. Using rhodamine 6G (R6G) as probe molecules with the concentration down to 10{sup −5} M, the Ag/Ni(OH){sub 2} composite film exhibits very high Raman scattering enhancement ability, possessing an enhancement factor as high as 5 × 10{sup 6}. It has been found that the enhancement ability of the substrate was strongly dependent on the size and interparticle gap of Ag NPs rather than the testing position on the film surface. In addition, the 3D structure of Ni(OH){sub 2} NS arrays and the charge transfer of Ag NPs may be responsible for this high sensitivity Raman phenomenon.

  11. Electronic Raman scattering as a function of doping in high-{Tc} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kendziora, C. [Naval Research Lab., Washington, DC (United States); Kelley, R.J.; Onellion, M. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.

    1996-12-31

    The authors report the results of Raman scattering from the electronic continuum in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} (Bi 2212) and Ti{sub 2}Ba{sub 2}CuO{sub 6+{delta}} (Tl 2201) high temperature superconductors with variations in the oxygen content, {delta}. Below {Tc}, a peak develops in the Raman continuum associated with the opening of a superconducting gap, {Delta}(k). By selecting the polarizations of incident and scattered light, they are sensitive to possible anisotropy of the gap within the a-b plane. Near optimal doping, both materials show gap anisotropy, with 2{Delta}/k{sub B}{Tc} values of 7.2 (B{sub 1g}) vs. 5.8 (A{sub 1g}) in Tl 2202 and 8.5 (B{sub 1g}) vs. 6.2 (A{sub 1g}) in Bi 2212. In contrast, both show an isotropic gap at much lower energy shifts when the carrier concentration is raised: 2{Delta}/k{sub B}{Tc} = 3.9 (5.5) for Tl 2201 (Bi 2212) with {Tc} = 37K (57K). The authors compare the observed spectra with calculations based on order parameters with d-wave as well as isotropic s-wave symmetry and conclude that raising the doping level reduces the gap anisotropy to near zero.

  12. Raman spectroscopic determination of the molecular constants of the hydrogen isotopologues with high accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Krasch, Bennet; Mirz, Sebastian; Groessle, Robin [Karlsruhe Institute of Technology KIT (Germany). Institute for Technical Physics (ITEP), Tritium Laboratory Karlsruhe (TLK); Collaboration: KATRIN-Collaboration

    2016-07-01

    The interest in the thermodynamic properties of gases as the chemical equilibrium is faced by the challenge of time-consuming and technical extensive experimental setups. One possible solution is the derivation of these properties from the molecular constants. The rotational and vibrational movement of diatomic molecules, as the hydrogen isotopologues, is described by the concept of the rotational anharmonic oscillator. The molecular constants are the free parameters of this concept. Molecular constants themselves can be determined by measuring the line position of rotational and/or rotational transitions e.g. with Raman spectroscopy for hydrogen as it has been done since several years. In this contribution a Raman method was development to measure the molecular constant of the hydrogen isotopologues with high accuracy to obtain reliable results. But not only the method was development but also a complete measurement uncertainty budget was set up. The uncertainty budget contains all possible sources for uncertainties from the measurement period or the analysis process as well the contribution of each single uncertainty. The method and the uncertainty budget were exemplary tested on Deuterium.

  13. Structural changes in cartilage and collagen studied by high temperature Raman spectroscopy.

    Science.gov (United States)

    Fields, Mark; Spencer, Nicholas; Dudhia, Jayesh; McMillan, Paul F

    2017-02-22

    Understanding the high temperature behavior of collagen and collagenous tissue is important for surgical procedures and biomaterials processing for the food, pharmaceutical and cosmetics industries. One primary event for proteins is thermal denaturation that involves unfolding the polypeptide chains while maintaining the primary structure intact. Collagen in the extracellular matrix of cartilage and other connective tissue is a hierarchical material containing bundles of triple-helical fibers associated with water and proteoglycan components. Thermal analysis of dehydrated collagen indicates irreversible denaturation at high temperature between 135-200°C, with another reversible event at ∼60-80°C for hydrated samples. We report high temperature Raman spectra for freeze-dried cartilage samples that show an increase in laser-excited fluorescence interpreted as conformational changes associated with denaturation above 140°C. Spectra for separated collagen and proteoglycan fractions extracted from cartilage indicate the changes are associated with collagen. The Raman data also show appearance of new features indicating peptide bond hydrolysis at high temperature implying that molecular H2 O is retained within the freeze-dried tissue. This is confirmed by thermogravimetric analysis that show 5-7 wt% H2 O remaining within freeze-dried cartilage that is released progressively upon heating up to 200°C. Spectra obtained after exposure to high temperature and re-hydration following recovery indicate that the capacity of the denatured collagen to re-absorb water is reduced. Our results are important for revealing the presence of bound H2 O within the collagen component of connective tissue even after freeze-drying and its role in denaturation that is accompanied by or perhaps preceded by breakdown of the primary polypeptide structure. This article is protected by copyright. All rights reserved.

  14. Surface-enhanced Raman imaging of cell membrane by a highly homogeneous and isotropic silver nanostructure

    Science.gov (United States)

    Zito, Gianluigi; Rusciano, Giulia; Pesce, Giuseppe; Dochshanov, Alden; Sasso, Antonio

    2015-04-01

    Label-free chemical imaging of live cell membranes can shed light on the molecular basis of cell membrane functionalities and their alterations under membrane-related diseases. In principle, this can be done by surface-enhanced Raman scattering (SERS) in confocal microscopy, but requires engineering plasmonic architectures with a spatially invariant SERS enhancement factor G(x, y) = G. To this end, we exploit a self-assembled isotropic nanostructure with characteristics of homogeneity typical of the so-called near-hyperuniform disorder. The resulting highly dense, homogeneous and isotropic random pattern consists of clusters of silver nanoparticles with limited size dispersion. This nanostructure brings together several advantages: very large hot spot density (~104 μm-2), superior spatial reproducibility (SD cell membranes with confocal resolution. In particular, SERS imaging is here demonstrated on red blood cells in vitro in order to use the Raman-resonant heme of the cell as a contrast medium to prove spectroscopic detection of membrane molecules. Numerical simulations also clarify the SERS characteristics of the substrate in terms of electromagnetic enhancement and distance sensitivity range consistently with the experiments. The large SERS-active area is intended for multi-cellular imaging on the same substrate, which is important for spectroscopic comparative analysis of complex organisms like cells. This opens new routes for in situ quantitative surface analysis and dynamic probing of living cells exposed to membrane-targeting drugs.Label-free chemical imaging of live cell membranes can shed light on the molecular basis of cell membrane functionalities and their alterations under membrane-related diseases. In principle, this can be done by surface-enhanced Raman scattering (SERS) in confocal microscopy, but requires engineering plasmonic architectures with a spatially invariant SERS enhancement factor G(x, y) = G. To this end, we exploit a self

  15. Demonstrating the capability of the high-performance plasmonic gallium-graphene couple.

    Science.gov (United States)

    Losurdo, Maria; Yi, Congwen; Suvorova, Alexandra; Rubanov, Sergey; Kim, Tong-Ho; Giangregorio, Maria M; Jiao, Wenyuan; Bergmair, Iris; Bruno, Giovanni; Brown, April S

    2014-03-25

    Metal nanoparticle (NP)-graphene multifunctional platforms are of great interest for exploring strong light-graphene interactions enhanced by plasmons and for improving performance of numerous applications, such as sensing and catalysis. These platforms can also be used to carry out fundamental studies on charge transfer, and the findings can lead to new strategies for doping graphene. There have been a large number of studies on noble metal Au-graphene and Ag-graphene platforms that have shown their potential for a number of applications. These studies have also highlighted some drawbacks that must be overcome to realize high performance. Here we demonstrate the promise of plasmonic gallium (Ga) nanoparticle (NP)-graphene hybrids as a means of modulating the graphene Fermi level, creating tunable localized surface plasmon resonances and, consequently, creating high-performance surface-enhanced Raman scattering (SERS) platforms. Four prominent peculiarities of Ga, differentiating it from the commonly used noble (gold and silver) metals are (1) the ability to create tunable (from the UV to the visible) plasmonic platforms, (2) its chemical stability leading to long-lifetime plasmonic platforms, (3) its ability to n-type dope graphene, and (4) its weak chemical interaction with graphene, which preserves the integrity of the graphene lattice. As a result of these factors, a Ga NP-enhanced graphene Raman intensity effect has been observed. To further elucidate the roles of the electromagnetic enhancement (or plasmonic) mechanism in relation to electron transfer, we compare graphene-on-Ga NP and Ga NP-on-graphene SERS platforms using the cationic dye rhodamine B, a drug model biomolecule, as the analyte.

  16. Quantitative proteomics using the high resolution accurate mass capabilities of the quadrupole-orbitrap mass spectrometer.

    Science.gov (United States)

    Gallien, Sebastien; Domon, Bruno

    2014-08-01

    High resolution/accurate mass hybrid mass spectrometers have considerably advanced shotgun proteomics and the recent introduction of fast sequencing capabilities has expanded its use for targeted approaches. More specifically, the quadrupole-orbitrap instrument has a unique configuration and its new features enable a wide range of experiments. An overview of the analytical capabilities of this instrument is presented, with a focus on its application to quantitative analyses. The high resolution, the trapping capability and the versatility of the instrument have allowed quantitative proteomic workflows to be redefined and new data acquisition schemes to be developed. The initial proteomic applications have shown an improvement of the analytical performance. However, as quantification relies on ion trapping, instead of ion beam, further refinement of the technique can be expected.

  17. Synthesis of gold nanoflowers using deep eutectic solvent with high surface enhanced Raman scattering properties

    Science.gov (United States)

    Aghakhani Mahyari, Farzaneh; Tohidi, Maryam; Safavi, Afsaneh

    2016-09-01

    A facile, seed-less and one-pot method was developed for synthesis of gold nanoflowers with multiple tips through reduction of HAuCl4 with deep eutectic solvent at room temperature. This solvent is eco-friendly, low-cost, non-toxic and biodegradable and can act as both reducing and shape-controlling agent. In this protocol, highly branched and stable gold nanoflowers were obtained without using any capping agent. The obtained products were characterized by different techniques including, field emission scanning electron microscopy, transmission electron microscopy, x-ray diffraction and UV-vis spectroscopy. The as-prepared gold nanoflowers exhibit efficient surface-enhanced Raman scattering (SERS) properties which can be used as excellent substrates for SERS.

  18. Theoretical treatment of modal instability in high-power cladding-pumped Raman amplifiers

    Science.gov (United States)

    Naderi, Shadi; Dajani, Iyad; Grosek, Jacob; Madden, Timothy

    2015-03-01

    Cladding-pumped Raman fiber amplifiers (RFA) have been proposed as gain media to achieve power scaling. It is well-known that the onset of the modal instability (MI) phenomenon is a limiting factor for achieving higher output powers in Yb-doped fiber amplifiers with good beam quality. In this paper, we present an analytical approach to the investigation of the MI phenomenon in high-power, cladding-pumped RFAs. By utilizing the conservation of the number of photons and the conservation of energy in the absence of loss, the nonlinear equations for the propagation of the pump power and the total signal power can be decoupled from one another. Decoupling lead to exact solutions for the pump power and transverse modes signal powers. Further we investigate various MI suppression techniques including increasing the seed power and gain-tailored design.

  19. High-Speed Linear Raman Spectroscopy for Instability Analysis of a Bluff Body Flame

    Science.gov (United States)

    Kojima, Jun; Fischer, David

    2013-01-01

    We report a high-speed laser diagnostics technique based on point-wise linear Raman spectroscopy for measuring the frequency content of a CH4-air premixed flame stabilized behind a circular bluff body. The technique, which primarily employs a Nd:YLF pulsed laser and a fast image-intensified CCD camera, successfully measures the time evolution of scalar parameters (N2, O2, CH4, and H2O) in the vortex-induced flame instability at a data rate of 1 kHz. Oscillation of the V-shaped flame front is quantified through frequency analysis of the combustion species data and their correlations. This technique promises to be a useful diagnostics tool for combustion instability studies.

  20. Preparation of Highly Squeezed States and Multi-component Entangled Coherent States via the Raman Interaction

    Institute of Scientific and Technical Information of China (English)

    ZHENG Sbi-Biao

    2002-01-01

    A method is presented for generating highly squeezed states of a cavity field via the atom-cavity field interaction of the Raman type. In the scheme a sequence of three-level A-type atoms interacts with a cavity field, displaced by a classical source, in a Rarman manner. Then the atomic states are measured. By this way the cavity field may collapse onto a superposition of several coherent states, which exhibits strong squeezing. The scheme can also be used to prepare superpositions of many two-mode coherent states for two cavity fields. The coherent states in each mode are on a straight line. This is the first way for preparing multi-component entangled coherent states of this type in cavity QED.

  1. Evaluation of the diagnostic potential of ex vivo Raman spectroscopy in gastric cancers: fingerprint versus high wavenumber

    Science.gov (United States)

    Zhou, Xueqian; Dai, Jianhua; Chen, Yao; Duan, Guangjie; Liu, Yulong; Zhang, Hua; Wu, Hongbo; Peng, Guiyong

    2016-10-01

    The aim of this study was to apply Raman spectroscopy in the high wavenumber (HW) region (2800 to 3000 cm-1) for ex vivo detection of gastric cancer and compare its diagnostic potential with that of the fingerprint (FP) region (800 to 1800 cm-1). Raman spectra were collected in the FP and HW regions to differentiate between normal mucosa (n=38) and gastric cancer (n=37). The distinctive Raman spectral differences between normal and cancer tissues are observed at 853, 879, 1157, 1319, 1338, 1448, and 2932 cm-1 and are primarily related to proteins, lipids, nucleic acids, collagen, and carotenoids in the tissue. In FP and HW Raman spectroscopy for diagnosis of gastric cancer, multivariate diagnostic algorithms based on partial-least-squares discriminant analysis, together with leave-one-sample-out cross validation, yielded diagnostic sensitivities of 94.59% and 81.08%, and specificities of 86.84% and 71.05%, respectively. Receiver operating characteristic analysis further confirmed that the FP region model performance is superior to that of the HW region model. Better differentiation between normal and gastric cancer tissues can be achieved using FP Raman spectroscopy and PLS-DA techniques, but the complementary natures of the FP and HW regions make both of them useful in diagnosis of gastric cancer.

  2. Strategic alliances and product development in high technology new firms: The moderating effect of technological capabilities

    NARCIS (Netherlands)

    Haeussler, C.; Patzelt, H.; Zahra, S.A.

    2012-01-01

    High technology new firms have extensively used strategic alliances to gain access to knowledge, resources and capabilities. However, given their inexperience and limited resources, these firms are vulnerable to their more established partners' potential opportunism. This raises the question: How ca

  3. Are "High Potential" Executives Capable of Building Learning-Oriented Organisations? Reflections on the French Case

    Science.gov (United States)

    Belet, Daniel

    2007-01-01

    Purpose: The author's interest in learning organisation development leads him to examine large French companies' practices regarding "high potential" executives policies and to question their selection and development processes and their capabilities to develop learning oriented organisations.The author also tries to explain why most large French…

  4. Raman spectroscopy of CaSnO{sub 3} at high temperature: a highly quasi-harmonic perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Redfern, S A T; Salje, E K H [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom); Chen, C-J; Kung, J [Department of Earth Sciences, National Chen Kung University, 1 University Road, 701-Tainan, Taiwan (China); Chaix-Pluchery, O; Kreisel, J, E-mail: satr@cam.ac.uk [Laboratoire des Materiaux et du Genie Physique, Grenoble INP, CNRS, Minatec, 3 Parvis Louis Neel, F-38016 Grenoble (France)

    2011-10-26

    Calcium stannate perovskite (CaSnO{sub 3}) has been studied by Raman spectroscopy at two excitation wavelengths (514.5 and 632.8 nm). No phase transition was observed. Rather, the thermal evolution of the Raman lines showed a high degree of harmonicity with small Grueneisen parameters and thermal line broadening following {Gamma} = Acoth{theta}/T, where the quantum temperature {theta} is determined by the phonon branch without further coupling with other degrees of freedom. The geometrical nature of phonon lines has been identified. High-temperature powder x-ray diffraction measurements provide thermal expansion coefficients of {alpha}{sub x} = 13.9 x 10{sup -6} K{sup -1}, {alpha}{sub y} = 2.7 x 10{sup -6} K{sup -1}, {alpha}{sub z} = 14.3 x 10{sup -6} K{sup -1}. The strongly quasi-harmonic behaviour observed and the lack of any indication of instability with respect to the post-perovskite structure points to the strongly first-order character of the reported perovskite to post-perovskite phase transition in this material, which appears to behave as a very good analogue to MgSiO{sub 3} in the Earth's interior. (paper)

  5. Theoretical and experimental research on high-order stimulated Raman scattering in KGd(WO4)2

    Science.gov (United States)

    Wang, Xiaobin; Kang, Wenyun; Song, Xiaoquan; Xie, Ping; Zong, Nan; Tu, Wei

    2017-02-01

    Eight wavelengths (465, 485, 508, 532, 559, 588, 621, and 658 nm) were synchronously generated by a single-pass potassium gadolinium tungstate (KGW) crystal Raman arrangement, which was pumped by a 532 nm, picosecond Nd: YAG laser with high peak power. To the best of our knowledge, this single-pass arrangement synchronously generated the highest-order Stokes and anti-Stokes among all known KGW Raman lasers. The first- to seventh-order Stokes conversion efficiency was calculated using Raman coupled equations. Further, the numerical results of third-order Stokes (621 nm) conversion efficiency were in good agreement with the experimental ones. We also analyze and discuss the factors because of which higher-order Stokes were not generated.

  6. High heat flux capabilities of the Magnum-PSI linear plasma device

    Energy Technology Data Exchange (ETDEWEB)

    De Temmerman, G., E-mail: g.c.detemmerman@differ.nl; Berg, M.A. van den; Scholten, J.; Lof, A.; Meiden, H.J. van der; Eck, H.J.N. van; Morgan, T.W.; Kruijf, T.M. de; Zeijlmans van Emmichoven, P.A.; Zielinski, J.J.

    2013-10-15

    Magnum-PSI is an advanced linear plasma device uniquely capable of producing plasma conditions similar to those expected in the divertor of ITER both steady-state and transients. The machine is designed both for fundamental studies of plasma–surface interactions under high heat and particle fluxes, and as a high-heat flux facility for the tests of plasma-facing components under realistic plasma conditions. To study the effects of transient heat loads on a plasma-facing surface, a novel pulsed plasma source system as well as a high power laser is available. In this article, we will describe the capabilities of Magnum-PSI for high-heat flux tests of plasma-facing materials.

  7. Low frequency Raman scattering for high resolution low temperature optical fiber sensors

    Science.gov (United States)

    Rabia, M. K.; Jurdyc, A.-M.; Le Brusq, J.; Champagnon, B.; Vouagner, D.

    2017-09-01

    Raman distributed optical fiber temperature sensors are based on the intensity ratio of the anti-Stokes to the Stokes Raman band at 440 cm-1 of silica. In this paper we predict that the sensitivity of the Raman measurements for low temperatures can be improved by considering the Boson peak in the low frequency Raman scattering domain at 60 cm-1. In this way Raman temperature sensors can be performed down to cryogenic temperatures. It is further shown that the Boson peak is less dependent than the 440 cm-1 band to the polarization of light. For the usual excitation at 1550 nm the anti-Stokes Boson peak at 1536 nm is in the low loss transmission window of the silica fibers.

  8. Molecular effects of high-pressure processing on food studied by resonance Raman.

    Science.gov (United States)

    Tintchev, Filip; Wackerbarth, Hainer; Kuhlmann, Uwe; Toepfl, Stefan; Knorr, Dietrich; Hildebrandt, Peter; Heinz, Volker

    2010-02-01

    Pressurization may cause unwanted side effects including color or texture changes of fish and meat. The color changes of poultry, pork, and smoked salmon were studied by CIE L*, a*, b* system, and resonance Raman (RR). High-pressure processing (HPP) of pork and chicken meat resulted in significant color modification at pressures higher than 270 and 280 MPa, respectively. RR spectra were taken after a high-pressure treatment of pork meat. According to the RR-data, deoxymyoglobin is the dominating myoglobin species in pork meat. High-pressure treatment causes conformational changes resulting in a stabile nonnative ferrous myoglobin species while the ferrous myoglobin state is maintained. High-pressure treatment causes a decrease of the relative RR intensities of astaxanthin by salmon as probed with 514 nm. RR spectra excited at 413 nm revealed a heterogeneous broadening of astaxanthin bands accompanied by the formation of deoxymyoglobin or deoxyhemoglobin. The broadening is interpreted as the degradation products of astaxanthin. Obviously, the high-pressure treatment of smoked salmon triggers redox processes of astaxanthin and the heme protein.

  9. Heat transfer capability simulation of high-temperature heat pipe in supersonic vehicle leading edge applications

    Directory of Open Access Journals (Sweden)

    Donghuan Liu

    2016-04-01

    Full Text Available A numerical method is proposed to determine the heat transfer capability of the high-temperature heat pipe and the stagnation temperature with supersonic vehicle leading edge applications. The finite element method is employed here to perform the temperature field simulation. Without considering the heat transfer limitations of the heat pipe, such as capillary limit and sonic limit, both numerical and experimental results indicate that equivalent high thermal conductivity method is a reasonable way to simulate the heat transfer capability of the high-temperature heat pipe in preliminary design of a heat-pipe-cooled leading edge. Several important parameters’ effects on the thermal protection performance are also numerically investigated.

  10. Continuous-wave Raman Lasing in Aluminum Nitride Microresonators

    CERN Document Server

    Liu, Xianwen; Xiong, Bing; Wang, Lai; Wang, Jian; Han, Yanjun; Hao, Zhibiao; Li, Hongtao; Luo, Yi; Yan, Jianchang; Wei, Tongbo; Zhang, Yun; Wang, Junxi

    2016-01-01

    We report the first investigation on continuous-wave Raman lasing in high-quality-factor aluminum nitride (AlN) microring resonators. Although wurtzite AlN is known to exhibit six Raman-active phonons, single-mode Raman lasing with low threshold and high slope efficiency is demonstrated. Selective excitation of A$_1^\\mathrm{TO}$ and E$_2^\\mathrm{high}$ phonons with Raman shifts of $\\sim$612 and 660 cm$^{-1}$ is observed by adjusting the polarization of the pump light. A theoretical analysis of Raman scattering efficiency within ${c}$-plane (0001) of AlN is carried out to help account for the observed lasing behavior. Bidirectional lasing is experimentally confirmed as a result of symmetric Raman gain in micro-scale waveguides. Furthermore, second-order Raman lasing with unparalleled output power of $\\sim$11.3 mW is obtained, which offers the capability to yield higher order Raman lasers for mid-infrared applications.

  11. High-sensitivity pesticide detection using particle-enhanced resonant Raman scattering

    Science.gov (United States)

    Ranjan, Bikas; Saito, Yuika; Verma, Prabhat

    2016-03-01

    The use of pesticides in agriculture has raised concerns, as even a small residual of pesticide on food can be harmful. It is therefore of great importance to develop a robust technique to detect tiny amounts of pesticides. Although Raman spectroscopy is frequently used for chemical identification, it is not suitable for extremely low molecular concentrations. We propose a technique called particle-enhanced resonant Raman spectroscopy to detect extremely low concentrations of pesticides, where gold nanoparticles of desired plasmonic resonance are synthesized to match the resonance in Raman scattering. We successfully demonstrated the detection of extremely low amounts of pesticides on oranges.

  12. Highly sensitive and reproducible silicon-based surface-enhanced Raman scattering sensors for real applications.

    Science.gov (United States)

    Wang, Houyu; Jiang, Xiangxu; He, Yao

    2016-08-15

    During the past few decades, thanks to silicon nanomaterials' outstanding electronic/optical/mechanical properties, large surface-to-volume ratio, abundant surface chemistry, facile tailorability and good compatibility with modern semiconductor industry, different dimensional silicon nanostructures have been widely employed for rationally designing and fabricating high-performance surface-enhanced Raman scattering (SERS) sensors for the detection of various chemical and biological species. Among these, two-dimensional silicon nanostructures made of metal nanoparticle-modified silicon wafers and three-dimensional silicon nanostructures made of metal nanoparticle-decorated SiNW arrays are of particular interest, and have been extensively exploited as promising silicon-based SERS-active substrates for the construction of high-performance SERS sensors. With an aim to retrospect these important and exciting achievements, we herein focus on reviewing recent representative studies on silicon-based SERS sensors for sensing applications from a broad perspective and possible future direction, promoting readers' awareness of these novel powerful silicon-based SERS sensing technologies. Firstly, we summarize the two unique merits of silicon-based SERS sensors, and those are high sensitivity and good reproducibility. Next, we present recent advances of two- and three-dimensional silicon-based SERS sensors, especially for real applications. Finally, we discuss the major challenges and prospects for the development of silicon-based SERS sensors.

  13. High brightness, quantum-defect-limited conversion efficiency in cladding-pumped Raman fiber amplifiers and oscillators.

    Science.gov (United States)

    Heebner, John E; Sridharan, Arun K; Dawson, Jay W; Messerly, Michael J; Pax, Paul H; Shverdin, Miro Y; Beach, Raymond J; Barty, Chris P J

    2010-07-05

    We present a detailed theoretical investigation of cladding-pumped Raman fiber amplification in an unexplored parameter space of high conversion efficiency (> 60%) and high brightness enhancement (> 1000). Fibers with large clad-to-core diameter ratios can provide a promising means for Raman-based brightness enhancement of diode pump sources. Unfortunately, the diameter ratio cannot be extended indefinitely since the intensity generated in the core can greatly exceed that in the cladding long before the pump is fully depleted. If left uncontrolled, this leads to the generation of parasitic second-order Stokes wavelengths in the core, limiting the conversion efficiency and as we will show, clamping the achievable brightness enhancement. Using a coupled-wave formalism, we present the upper limit on brightness enhancement as a function of diameter ratio for conventionally guided fibers. We further present strategies for overcoming this limit based upon depressed well core designs. We consider two configurations: 1) pulsed cladding-pumped Raman fiber amplifier (CPRFA) and 2) cw cladding-pumped Raman fiber laser (CPRFL).

  14. Silicon nanocrystals with high boron and phosphorus concentration hydrophilic shell—Raman scattering and X-ray photoelectron spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Minoru, E-mail: fujii@eedept.kobe-u.ac.jp; Sugimoto, Hiroshi; Hasegawa, Masataka; Imakita, Kenji [Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501 (Japan)

    2014-02-28

    Boron (B) and phosphorus (P) codoped silicon (Si) nanocrystals, which exhibit very wide range tunable luminescence due to the donor to acceptor transitions and can be dispersed in polar liquids without organic ligands, are studied by Raman scattering and X-ray photoelectron spectroscopies. Codoped Si nanocrystals exhibit a Raman spectrum significantly different from those of intrinsic ones. First, the Raman peak energy is almost insensitive to the size and is very close to that of bulk Si crystal in the diameter range of 2.7 to 14 nm. Second, the peak is much broader than that of intrinsic ones. Furthermore, an additional broad peak, the intensity of which is about 20% of the main peak, appears around 650 cm{sup −1}. The peak can be assigned to local vibrational modes of substitutional B and B-P pairs, B clusters, B-interstitial clusters, etc. in Si crystal. The Raman and X-ray photoelectron spectroscopic studies suggest that a crystalline shell heavily doped with these species is formed at the surface of a codoped Si nanocrystal and it induces the specific properties, i.e., hydrophilicity, high-stability in water, high resistance to hydrofluoric acid, etc.

  15. Synthesis and performances of polycarboxylate superplaticizer with clay-inerting and high slump retention capability

    Science.gov (United States)

    Qian, Shanshan; Jiang, Haidong; Ding, Bei; Wang, Yi; Zheng, Chunyang; Guo, Zhaolai

    2017-03-01

    Macromolecules with pendant chlorine groups on their main chains were synthesized via free-radical copolymerization of 2-hydroxyethyl acrylate(HEA), TPEG and vinylbenzyl chloride(VBC) in the presence of intiator and chain transfer agent according to molecular structure design principle. The subsequent Arbuzov reaction between trimethoxyphosphine(TMP) and chlorine groups of macromolecules(PHVT) gave rise to new type of polycarboxylate superplaticizer with clay-inerting and high slump retention capability. The molecular structure of superplasticizer was determined by Fourier Transform Infrared Spectroscopy (FT-IR) and Gel Permeation Chromatography (GPC), respectively. The adaptability of clays, Zata potential, adsorption behavior and application performance in concrete were measured. The results shows that the polycarboxylate superplaticizer we prepared has good clay compatibility, excellent clay-inerting and high slump retention capability.

  16. High Altitude Platforms for Disaster Recovery: Capabilities, Strategies, and Techniques for Providing Emergency Telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Juan D. Deaton

    2008-05-01

    Natural disasters and terrorist acts have significant potential to disrupt emergency communication systems. These emergency communication networks include first-responder, cellular, landline, and emergency answering services such as 911, 112, or 999. Without these essential emergency communications capabilities, search, rescue, and recovery operations during a catastrophic event will be severely debilitated. High altitude platforms could be fitted with telecommunications equipment and used to support these critical communications missions once the catastrophic event occurs. With the ability to be continuously on station, HAPs provide excellent options for providing emergency coverage over high-risk areas before catastrophic incidents occur. HAPs could also provide enhanced 911 capabilities using either GPS or reference stations. This paper proposes potential emergency communications architecture and presents a method for estimating emergency communications systems traffic patterns for a catastrophic event.

  17. High Altitude Platforms for Disaster Recovery: Capabilities, Strategies, and Techniques for Emergency Telecommunications

    Directory of Open Access Journals (Sweden)

    Juan D. Deaton

    2008-09-01

    Full Text Available Natural disasters and terrorist acts have significant potential to disrupt emergency communication systems. These emergency communication networks include first-responder, cellular, landline, and emergency answering services such as 911, 112, or 999. Without these essential emergency communications capabilities, search, rescue, and recovery operations during a catastrophic event will be severely debilitated. High altitude platforms could be fitted with telecommunications equipment and used to support these critical communications missions once the catastrophic event occurs. With the ability to be continuously on station, HAPs provide excellent options for providing emergency coverage over high-risk areas before catastrophic incidents occur. HAPs could also provide enhanced 911 capabilities using either GPS or reference stations. This paper proposes potential emergency communications architecture and presents a method for estimating emergency communications systems traffic patterns for a catastrophic event.

  18. High Altitude Platforms for Disaster Recovery: Capabilities, Strategies, and Techniques for Emergency Telecommunications

    Directory of Open Access Journals (Sweden)

    Deaton JuanD

    2008-01-01

    Full Text Available Abstract Natural disasters and terrorist acts have significant potential to disrupt emergency communication systems. These emergency communication networks include first-responder, cellular, landline, and emergency answering services such as 911, 112, or 999. Without these essential emergency communications capabilities, search, rescue, and recovery operations during a catastrophic event will be severely debilitated. High altitude platforms could be fitted with telecommunications equipment and used to support these critical communications missions once the catastrophic event occurs. With the ability to be continuously on station, HAPs provide excellent options for providing emergency coverage over high-risk areas before catastrophic incidents occur. HAPs could also provide enhanced 911 capabilities using either GPS or reference stations. This paper proposes potential emergency communications architecture and presents a method for estimating emergency communications systems traffic patterns for a catastrophic event.

  19. High-rate capable, low-material budget floating strip Micromegas

    Energy Technology Data Exchange (ETDEWEB)

    Bortfeldt, Jonathan; Biebel, Otmar; Flierl, Bernhard; Grossmann, Johannes; Hertenberger, Ralf; Loesel, Philipp; Mueller, Ralph; Pree, Elias; Pritzl, Stefanie [LS Schaile, LMU Muenchen (Germany)

    2015-07-01

    Floating strip Micromegas are versatile and high-rate capable particle detectors. Single particle tracking of medium-energy ions at fluxes up to 7 MHz/cm{sup 2} is possible, stable operation at rates of 2 GHz has been observed. Due to the nearly floating copper anode strips the detector is highly discharge tolerant. A detector system consisting of four low-material budget floating strip Micromegas with an active area of 6.4 cm x 6.4 cm and a scintillator based range telescope has been tested in 23 MeV proton beams at the tandem accelerator Garching. Fast Ne:CF{sub 4} based gas mixtures have been investigated which allow for a further increase of the high-rate capability by a factor of three. A synchronous readout of the strip detectors and the range telescope has been achieved. We report on the track inclination reconstruction capabilities in a single detector plane and on the measured electron drift velocity with the new gas mxitures. We furthermore present ion range radiography measurements with the combined system.

  20. Hollow Au/Ag nanostars displaying broad plasmonic resonance and high surface-enhanced Raman sensitivity

    Science.gov (United States)

    Garcia-Leis, Adianez; Torreggiani, Armida; Garcia-Ramos, Jose Vicente; Sanchez-Cortes, Santiago

    2015-08-01

    Bimetallic Au/Ag hollow nanostar (HNS) nanoparticles with different morphologies were prepared in this work. These nanoplatforms were obtained by changing the experimental conditions (concentration of silver and chemical reductors, hydroxylamine and citrate) and by using Ag nanostars as template nanoparticles (NPs) through galvanic replacement. The goal of this research was to create bimetallic Au/Ag star-shaped nanoparticles with advanced properties displaying a broader plasmonic resonance, a cleaner exposed surface, and a high concentration of electromagnetic hot spots on the surface provided by the special morphology of nanostars. The size, shape, and composition of Ag as well as their optical properties were studied by extinction spectroscopy, hyperspectral dark field microscopy, transmission and scanning electron microscopy (TEM and SEM), and energy dispersive X-ray spectroscopy (EDX). Finally, the surface-enhanced Raman scattering (SERS) activity of these HNS was investigated by using thioflavin T, a biomarker of the β-amyloid fibril formation, responsible for Alzheimer's disease. Lucigenin, a molecule displaying different SERS activities on Au and Ag, was also used to explore the presence of these metals on the NP surface. Thus, a relationship between the morphology, plasmon resonance and SERS activity of these new NPs was made.Bimetallic Au/Ag hollow nanostar (HNS) nanoparticles with different morphologies were prepared in this work. These nanoplatforms were obtained by changing the experimental conditions (concentration of silver and chemical reductors, hydroxylamine and citrate) and by using Ag nanostars as template nanoparticles (NPs) through galvanic replacement. The goal of this research was to create bimetallic Au/Ag star-shaped nanoparticles with advanced properties displaying a broader plasmonic resonance, a cleaner exposed surface, and a high concentration of electromagnetic hot spots on the surface provided by the special morphology of nanostars

  1. High Average Power Raman Conversion in Diamond: ’Eyesafe’ Output and Fiber Laser Conversion

    Science.gov (United States)

    2015-06-19

    power. The efficiencies and brightness achieved are found to be higher than expected by current theories for thermal effects in diamond. The project...understand the importance of other cavity parameters on laser behaviour in order to assist with future optimization of designs. We thus developed a model...three areas not originally planned in the proposal. 1) Raman beam combination The technique of Raman beam combination, which has been investigated

  2. Plasmonic tooth-multilayer structure with high enhancement field for surface enhanced Raman spectroscopy

    Science.gov (United States)

    Huang, Li-Chung; Wang, Zhiyu; Clark, J. Kenji; Ho, Ya-Lun; Delaunay, Jean-Jacques

    2017-03-01

    The significant enhancement seen in surface-enhanced Raman scattering (SERS) heavily relies on the ability of plasmonic structures to strongly confine light. Current techniques used to fabricate plasmonic nanostructures have been limited in their reproducibility for bottom-up techniques or their feature size for top-down techniques. Here, we propose a tooth multilayer structure that can be fabricated by using physical vapor deposition and selective wet etching, achieving extremely small feature sizes and high reproducibility. A multilayer structure composed of two alternating materials whose thicknesses can be controlled accurately in the nanometer range is deposited on a flat substrate using ion-beam sputtering. Subsequent selective wet etching is used to form nanogaps in one of the materials constituting the multilayer, with the depth of the nanogaps being controlled by the wet etching time. Combining both techniques can allow the nanogap dimensions to be controlled at sub 10 nm length scale, thus achieving a tooth multilayer structure with high enhancement and tunability of the resonance mode over a broad range, ideal for SERS applications.

  3. Quantitative Analysis of Spectral Interference of Spontaneous Raman Scattering in High-Pressure Fuel-Rich H2-Air Combustion

    Science.gov (United States)

    Kojima, Jun; Nguyen, Quang-Viet

    2004-01-01

    We present a theoretical study of the spectral interferences in the spontaneous Raman scattering spectra of major combustion products in 30-atm fuel-rich hydrogen-air flames. An effective methodology is introduced to choose an appropriate line-shape model for simulating Raman spectra in high-pressure combustion environments. The Voigt profile with the additive approximation assumption was found to provide a reasonable model of the spectral line shape for the present analysis. The rotational/vibrational Raman spectra of H2, N2, and H2O were calculated using an anharmonic-oscillator model using the latest collisional broadening coefficients. The calculated spectra were validated with data obtained in a 10-atm fuel-rich H2-air flame and showed excellent agreement. Our quantitative spectral analysis for equivalence ratios ranging from 1.5 to 5.0 revealed substantial amounts of spectral cross-talk between the rotational H2 lines and the N2 O-/Q-branch; and between the vibrational H2O(0,3) line and the vibrational H2O spectrum. We also address the temperature dependence of the spectral cross-talk and extend our analysis to include a cross-talk compensation technique that removes the nterference arising from the H2 Raman spectra onto the N2, or H2O spectra.

  4. High pressure behavior of nano-crystalline CeO2 up to 35 GPa: a Raman investigation

    Science.gov (United States)

    Dogra, Sugandha; Dilawar Sharma, Nita; Singh, Jasveer; Poswal, Himanshu Kumar; Sharma, S. M.; Bandyopadhyay, A. K.

    2011-06-01

    The present paper reports the results of in situ Raman studies carried out on nano-crystalline CeO2 up to a pressure of 35 GPa at room temperature. The material was characterized at ambient conditions using X-ray diffraction and Raman spectroscopy and was found to have a cubic structure. We observed the Raman peak at ambient at 465 cm-1, which is characteristic of the cubic structure of the material. The sample was pressurized using a diamond anvil cell using ruby fluorescence as the pressure monitor, and the phase evolution was tracked by Raman spectroscopy. With an increase in the applied pressure, the cubic band was seen to steadily shift to higher wavenumbers. However, we observed the appearance of a number of new peaks around a pressure of about 34.7 GPa. CeO2 was found to undergo a phase transition to an orthorhombic α -PbCl2-type structure at this pressure. With the release of the applied pressure, the observed peaks steadily shift to lower wavenumbers. On decompression, the high pressure phase existed down to a total release of pressure.

  5. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, R. [Dalton Cumbrian Facility, Dalton Nuclear Institute, The University of Manchester, Westlakes Science & Technology Park, Moor Row, Whitehaven, Cumbria, CA24 3HA (United Kingdom); Jones, A.N., E-mail: Abbie.Jones@manchester.ac.uk [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom); McDermott, L.; Marsden, B.J. [Nuclear Graphite Research Group, School of MACE, The University of Manchester, Manchester, M13 9PL (United Kingdom)

    2015-12-15

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated ‘D’peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of ‘G’ and ‘D’ in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure. - Highlights: • Irradiated graphite

  6. Wavenumber selection based analysis in Raman spectroscopy improves skin cancer diagnostic specificity at high sensitivity levels (Conference Presentation)

    Science.gov (United States)

    Zhao, Jianhua; Zeng, Haishan; Kalia, Sunil; Lui, Harvey

    2017-02-01

    Background: Raman spectroscopy is a non-invasive optical technique which can measure molecular vibrational modes within tissue. A large-scale clinical study (n = 518) has demonstrated that real-time Raman spectroscopy could distinguish malignant from benign skin lesions with good diagnostic accuracy; this was validated by a follow-up independent study (n = 127). Objective: Most of the previous diagnostic algorithms have typically been based on analyzing the full band of the Raman spectra, either in the fingerprint or high wavenumber regions. Our objective in this presentation is to explore wavenumber selection based analysis in Raman spectroscopy for skin cancer diagnosis. Methods: A wavenumber selection algorithm was implemented using variably-sized wavenumber windows, which were determined by the correlation coefficient between wavenumbers. Wavenumber windows were chosen based on accumulated frequency from leave-one-out cross-validated stepwise regression or least and shrinkage selection operator (LASSO). The diagnostic algorithms were then generated from the selected wavenumber windows using multivariate statistical analyses, including principal component and general discriminant analysis (PC-GDA) and partial least squares (PLS). A total cohort of 645 confirmed lesions from 573 patients encompassing skin cancers, precancers and benign skin lesions were included. Lesion measurements were divided into training cohort (n = 518) and testing cohort (n = 127) according to the measurement time. Result: The area under the receiver operating characteristic curve (ROC) improved from 0.861-0.891 to 0.891-0.911 and the diagnostic specificity for sensitivity levels of 0.99-0.90 increased respectively from 0.17-0.65 to 0.20-0.75 by selecting specific wavenumber windows for analysis. Conclusion: Wavenumber selection based analysis in Raman spectroscopy improves skin cancer diagnostic specificity at high sensitivity levels.

  7. Design and Characterisation of Metallic Glassy Alloys of High Neutron Shielding Capability

    Science.gov (United States)

    Khong, J. C.; Daisenberger, D.; Burca, G.; Kockelmann, W.; Tremsin, A. S.; Mi, J.

    2016-11-01

    This paper reports the design, making and characterisation of a series of Fe-based bulk metallic glass alloys with the aim of achieving the combined properties of high neutron absorption capability and sufficient glass forming ability. Synchrotron X-ray diffraction and pair distribution function methods were used to characterise the crystalline or amorphous states of the samples. Neutron transmission and macroscopic attenuation coefficients of the designed alloys were measured using energy resolved neutron imaging method and the very recently developed microchannel plate detector. The study found that the newly designed alloy (Fe48Cr15Mo14C15B6Gd2 with a glass forming ability of Ø5.8 mm) has the highest neutron absorption capability among all Fe-based bulk metallic glasses so far reported. It is a promising material for neutron shielding applications.

  8. High-Accuracy Programmable Timing Generator with Wide-Range Tuning Capability

    Directory of Open Access Journals (Sweden)

    Ting-Li Chu

    2013-01-01

    Full Text Available In this paper, a high-accuracy programmable timing generator with wide-range tuning capability is proposed. With the aid of dual delay-locked loop (DLL, both of the coarse- and fine-tuning mechanisms are operated in precise closed-loop scheme to lessen the effects of the ambient variations. The timing generator can provide sub-gate resolution and instantaneous switching capability. The circuit is implemented and simulated in TSMC 0.18 μm 1P6M technology. The test chip area occupies 1.9 mm2. The reference clock cycle can be divided into 128 bins by interpolation to obtain 14 ps resolution with the clock rate at 550 MHz. The INL and DNL are within −0.21~+0.78 and −0.27~+0.43 LSB, respectively.

  9. NGNP: High Temperature Gas-Cooled Reactor Key Definitions, Plant Capabilities, and Assumptions

    Energy Technology Data Exchange (ETDEWEB)

    Phillip Mills

    2012-02-01

    This document is intended to provide a Next Generation Nuclear Plant (NGNP) Project tool in which to collect and identify key definitions, plant capabilities, and inputs and assumptions to be used in ongoing efforts related to the licensing and deployment of a high temperature gas-cooled reactor (HTGR). These definitions, capabilities, and assumptions are extracted from a number of sources, including NGNP Project documents such as licensing related white papers [References 1-11] and previously issued requirement documents [References 13-15]. Also included is information agreed upon by the NGNP Regulatory Affairs group's Licensing Working Group and Configuration Council. The NGNP Project approach to licensing an HTGR plant via a combined license (COL) is defined within the referenced white papers and reference [12], and is not duplicated here.

  10. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Science.gov (United States)

    Kim, Jongjin; Choi, Kyung Joon; Bahn, Chi Bum; Kim, Ji Hyun

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr2O3, NiCr2O4 and Fe3O4 at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  11. Assessing the effect of a high-fat diet on rodents' adipose tissue using Brillouin and Raman spectroscopy

    Science.gov (United States)

    Troyanova-Wood, Maria; Gobbell, Cassidy; Meng, Zhaokai; Yakovlev, Vladislav V.

    2016-03-01

    The purpose of this study is to evaluate the effect of a high-lipid diet on elasticity of adipose tissue. We employed dual Raman/Brillouin microspectroscopy to analyze brown and white adipose tissues obtained from adult rats. The rats were divided into two groups, one of which received a high-fat feed, while the other served as a control. We hypothesized that the changes in the elasticity of adipose tissues between the two groups can be successfully assessed using Brillouin spectroscopy. We found that the brown adipose tissue possessed a lesser Brillouin shift than the white adipose within each group and that the elastic modulus of both adipose tissues increases in the high-fat diet group. The Raman spectra provided supplementary chemical information and indicated an increase in the lipid-to-protein ratio in the brown adipose, but not in the white adipose.

  12. Depth profile study on Raman spectra of high-energy-electron-irradiated hydrogenated amorphous silicon films

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    According to the different penetration depths for the incident lights of 472 nm and 532 nm in hydrogenated amorphous silicon (a-Si:H) thin films, the depth profile study on Raman spectra of a-Si:H films was carried out. The network ordering evolution in the near surface and interior region of the unirradiated and irradiated a-Si:H films was investigated. The results show that there is a structural improvement in the shortand intermediate-range order towards the surface of the unirradiated a-Si:H films. The amorphous silicon network in the near and interior region becomes more disordered on the shortand intermediate-range scales after being irradiated with high energy electrons. However, the surface of the irradiated films becomes more disordered in comparison with their interior region, indicating that the created defects caused by electron irradiation are concentrated in the near surface of the irradiated films. Annealing eliminates the irradiation effects on a-Si:H thin films and the structural order of the irradiated films is similar to that of the unirradiated ones after being annealed. There exists a structural improvement in the shortand intermediate-range order towards the surface of the irradiated a-Si:H films after being annealed.

  13. Raman scattering spectroscopic study of n-pentane under high pressure.

    Science.gov (United States)

    Qiao, Erwei; Zheng, Haifei

    2005-05-01

    The Raman spectroscopy of n-pentane was investigated in a Moissanite anvil cell from 0.07 GPa to 4.77 GPa at ambient temperature. The result shows that the CH3 symmetric stretching vibration (2877 cm(-1)) and asymmetric stretching vibration (2964 cm(-1)), the CH2 symmetric stretching vibration (2856 cm(-1)) and asymmetric stretching vibration (2935 cm(-1)), and -(CH2)n- in-phase twist mode (1303 cm(-1)) shifted to higher wavenumbers almost linearly with increasing pressure. Around 2.4 GPa an abrupt visible change took place, indicating a sort of phenomenon of freezing due to over-pressurization. In the pressure range of 2.84 to 4.77 GPa a high-pressure phase transition may occur in the crystallized n-pentane. By determining pressure with the method of solid-liquid coexistence, we concluded that the equilibrium freezing pressure of n-pentane is 1.90 +/- 0.05 GPa at 27 degrees C.

  14. Additions and improvements to the high energy density physics capabilities in the FLASH code

    Science.gov (United States)

    Lamb, D. Q.; Flocke, N.; Graziani, C.; Tzeferacos, P.; Weide, K.

    2016-10-01

    FLASH is an open source, finite-volume Eulerian, spatially adaptive radiation magnetohydrodynamics code that has the capabilities to treat a broad range of physical processes. FLASH performs well on a wide range of computer architectures, and has a broad user base. Extensive high energy density physics (HEDP) capabilities have been added to FLASH to make it an open toolset for the academic HEDP community. We summarize these capabilities, emphasizing recent additions and improvements. In particular, we showcase the ability of FLASH to simulate the Faraday Rotation Measure produced by the presence of magnetic fields; and proton radiography, proton self-emission, and Thomson scattering diagnostics with and without the presence of magnetic fields. We also describe several collaborations with the academic HEDP community in which FLASH simulations were used to design and interpret HEDP experiments. This work was supported in part at the University of Chicago by the DOE NNSA ASC through the Argonne Institute for Computing in Science under field work proposal 57789; and the NSF under Grant PHY-0903997.

  15. Experimental test of the background rejection, through imaging capability, of a highly segmented AGATA germanium detector

    Energy Technology Data Exchange (ETDEWEB)

    Doncel, M., E-mail: doncel@usal.e [Laboratorio de Radiaciones Ionizantes, Universidad de Salamanca (Spain); Recchia, F. [INFN sezione di Padova, Padova (Italy); Quintana, B. [Laboratorio de Radiaciones Ionizantes, Universidad de Salamanca (Spain); Gadea, A. [IFIC Valencia, Valencia (Spain); INFN Laboratori Nazionali di Legnaro, Legnaro (Italy); Farnea, E. [INFN sezione di Padova, Padova (Italy)

    2010-10-21

    The development of highly segmented germanium detectors as well as the algorithms to identify the position of the interaction within the crystal opens the possibility to locate the {gamma}-ray source using Compton imaging algorithms. While the Compton-suppression shield, coupled to the germanium detector in conventional arrays, works also as an active filter against the {gamma} rays originated outside the target, the new generation of position sensitive {gamma}-ray detector arrays has to fully rely on tracking capabilities for this purpose. In specific experimental conditions, as the ones foreseen at radioactive beam facilities, the ability to discriminate background radiation improves the sensitivity of the gamma spectrometer. In this work we present the results of a measurement performed at the Laboratori Nazionali di Legnaro (LNL) aiming the evaluation of the AGATA detector capabilities to discriminate the origin of the {gamma} rays on an event-by-event basis. It will be shown that, exploiting the Compton scattering formula, it is possible to track back {gamma} rays coming from different positions, assigning them to specific emitting locations. These imaging capabilities are quantified for a single crystal AGATA detector.

  16. Test Capability Enhancements to the NASA Langley 8-Foot High Temperature Tunnel

    Science.gov (United States)

    Harvin, S. F.; Cabell, K. F.; Gallimore, S. D.; Mekkes, G. L.

    2006-01-01

    The NASA Langley 8-Foot High Temperature Tunnel produces true enthalpy environments simulating flight from Mach 4 to Mach 7, primarily for airbreathing propulsion and aerothermal/thermo-structural testing. Flow conditions are achieved through a methane-air heater and nozzles producing aerodynamic Mach numbers of 4, 5 or 7 and have exit diameters of 8 feet or 4.5 feet. The 12-ft long free-jet test section, housed inside a 26-ft vacuum sphere, accommodates large test articles. Recently, the facility underwent significant upgrades to support hydrocarbon fueled scramjet engine testing and to expand flight simulation capability. The upgrades were required to meet engine system development and flight clearance verification requirements originally defined by the joint NASA-Air Force X-43C Hypersonic Flight Demonstrator Project and now the Air Force X-51A Program. Enhancements to the 8-Ft. HTT were made in four areas: 1) hydrocarbon fuel delivery; 2) flight simulation capability; 3) controls and communication; and 4) data acquisition/processing. The upgrades include the addition of systems to supply ethylene and liquid JP-7 to test articles; a Mach 5 nozzle with dynamic pressure simulation capability up to 3200 psf, the addition of a real-time model angle-of-attack system; a new programmable logic controller sub-system to improve process controls and communication with model controls; the addition of MIL-STD-1553B and high speed data acquisition systems and a classified data processing environment. These additions represent a significant increase to the already unique test capability and flexibility of the facility, and complement the existing array of test support hardware such as a model injection system, radiant heaters, six-component force measurement system, and optical flow field visualization hardware. The new systems support complex test programs that require sophisticated test sequences and precise management of process fluids. Furthermore, the new systems, such

  17. Silver dendrites decorated filter membrane as highly sensitive and reproducible three dimensional surface enhanced Raman scattering substrates

    Science.gov (United States)

    Zhao, Bin; Lu, Ya; Zhang, Congyun; Fu, Yizheng; Moeendarbari, Sina; Shelke, Sandesh R.; Liu, Yaqing; Hao, Yaowu

    2016-11-01

    We report a novel and flexible surface enhanced Raman scattering (SERS) substrate based on filter membranes decorated with silver dendritic nanostructures. The SERS-active substrate was fabricated via electrodeposition, where hierarchical silver dendrites were uniformly and firmly deposited within and on the top of the porous filter membranes. The morphological evolution of silver dendrites was investigated at different deposition times, and the effect of the components of electrolyte was also studied. Finite difference time domain (FDTD) simulations were performed to reveal the distribution of electric filed when Ag dendrites were illuminated with 785 nm light. Such 3D SERS-active substrate exhibits extremely high sensitivity and excellent reproducibility. Raman signal sensitivity for rhodamine 6G was tested as high as 1 × 10-11 M with 12% average intensity variations at the major Raman peak. Additionally, the as-synthesized robust substrate displays high stability under an ambient condition for several months. This 3D eco-friendly filter membrane-based substrate provides not only high density of SERS hot spots, but also a very large area for capturing target analytes. It has potential applications for the detection of trace organic contaminants in the environment.

  18. High-fidelity simulation capability for virtual testing of seismic and acoustic sensors

    Science.gov (United States)

    Wilson, D. Keith; Moran, Mark L.; Ketcham, Stephen A.; Lacombe, James; Anderson, Thomas S.; Symons, Neill P.; Aldridge, David F.; Marlin, David H.; Collier, Sandra L.; Ostashev, Vladimir E.

    2005-05-01

    This paper describes development and application of a high-fidelity, seismic/acoustic simulation capability for battlefield sensors. The purpose is to provide simulated sensor data so realistic that they cannot be distinguished by experts from actual field data. This emerging capability provides rapid, low-cost trade studies of unattended ground sensor network configurations, data processing and fusion strategies, and signatures emitted by prototype vehicles. There are three essential components to the modeling: (1) detailed mechanical signature models for vehicles and walkers, (2) high-resolution characterization of the subsurface and atmospheric environments, and (3) state-of-the-art seismic/acoustic models for propagating moving-vehicle signatures through realistic, complex environments. With regard to the first of these components, dynamic models of wheeled and tracked vehicles have been developed to generate ground force inputs to seismic propagation models. Vehicle models range from simple, 2D representations to highly detailed, 3D representations of entire linked-track suspension systems. Similarly detailed models of acoustic emissions from vehicle engines are under development. The propagation calculations for both the seismics and acoustics are based on finite-difference, time-domain (FDTD) methodologies capable of handling complex environmental features such as heterogeneous geologies, urban structures, surface vegetation, and dynamic atmospheric turbulence. Any number of dynamic sources and virtual sensors may be incorporated into the FDTD model. The computational demands of 3D FDTD simulation over tactical distances require massively parallel computers. Several example calculations of seismic/acoustic wave propagation through complex atmospheric and terrain environments are shown.

  19. Beryl-II, a high-pressure phase of beryl: Raman and luminescence spectroscopy to 16.4 GPa

    Science.gov (United States)

    O'Bannon, Earl; Williams, Quentin

    2016-10-01

    The Raman and Cr3+ and V2+ luminescence spectra of beryl and emerald have been characterized up to 15.0 and 16.4 GPa, respectively. The Raman spectra show that an E 1g symmetry mode at 138 cm-1 shifts negatively by -4.57 (±0.55) cm-1/GPa, and an extrapolation of the pressure dependence of this mode indicates that a soft-mode transition should occur near 12 GPa. Such a transition is in accord with prior theoretical results. Dramatic changes in Raman mode intensities and positions occur between 11.2 and 15.0 GPa. These changes are indicative of a phase transition that primarily involves tilting and mild distortion of the Si6O18 rings. New Raman modes are not observed in the high-pressure phase, which indicates that the local bonding environment is not altered dramatically across the transition (e.g., changes in coordination do not occur). Both sharp line and broadband luminescence are observed for both Cr3+ and V2+ in emerald under compression to 16.4 GPa. The R-lines of both Cr3+ and V2+ shift to lower energy (longer wavelength) under compression. Both R-lines of Cr3+ split at ~13.7 GPa, and the V2+ R1 slope changes at this pressure and shifts more rapidly up to ~16.4 GPa. The Cr3+ R-line splitting and FWHM show more complex behavior, but also shift in behavior at ~13.7 GPa. These changes in the pressure dependency of the Cr3+ and V2+ R-lines and the changes in R-line splitting and FWHM at ~13.7 GPa further demonstrate that a phase transition occurs at this pressure, in good agreement with our Raman results. The high-pressure phase of beryl appears to have two Al sites that become more regular under compression. Hysteresis is not observed in our Raman or luminescence spectra on decompression, suggesting that this transition is second order in nature: The occurrence of a second-order transition near this pressure is also in accord with prior theoretical results. We speculate that the high-pressure phase (beryl-II) might be a mildly modulated structure, and/or that

  20. Comparison of High Performance Network Options: EDR InfiniBand vs.100Gb RDMA Capable Ethernet

    Energy Technology Data Exchange (ETDEWEB)

    Kachelmeier, Luke Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Univ. of New Mexico, Albuquerque, NM (United States); Van Wig, Faith Virginia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Missouri Univ. of Science and Technology, Rolla, MO (United States); Erickson, Kari Natania [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2016-08-08

    These are the slides for a presentation at the HPC Mini Showcase. This is a comparison of two different high performance network options: EDR InfiniBand and 100Gb RDMA capable ethernet. The conclusion of this comparison is the following: there is good potential, as shown with the direct results; 100Gb technology is too new and not standardized, thus deployment effort is complex for both options; different companies are not necessarily compatible; if you want 100Gb/s, you must get it all from one place.

  1. High-rate capability silicon decorated vertically aligned carbon nanotubes for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Gohier, Aurelien; Kim, Ki-Hwan; Maurice, Jean-Luc; Cojocaru, Costel Sorin [Laboratoire de Physique des Interfaces et des Couches Minces, LPICM, Ecole Polytechnique, route de Saclay, 91128 Palaiseau Cedex (France); Laik, Barbara; Pereira-Ramos, Jean-Pierre [Institut de Chimie et des Materiaux Paris-Est, ICMPE/GESMAT, UMR 7182 CNRS-UPEC, 2 rue Henri Dunant, 94320 Thiais (France); Van, Pierre Tran [Renault SAS, DREAM/DETA/SEE, 1, avenue du Golf, 78288 Guyancourt (France)

    2012-05-15

    The concept of a hybrid nanostructured collector made of thin vertically aligned carbon nanotubes (CNTs) decorated with Si nanoparticles provides high power density anodes in lithium-ion batteries. An impressive rate capability is achieved due to the efficient electronic conduction of CNTs combined with well defined electroactive Si nanoparticles: capacities of 3000 mAh g{sup -1} at 1.3C and 800 mAh g{sup -1} at 15C are achieved. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. New Active Organic Substance in Oyster Shell Capable of Scavenging Oxygen Free Radicals with High Efficiency

    Institute of Scientific and Technical Information of China (English)

    MA Jian-hua

    2008-01-01

    A light purple organic active substance capable of scavenging hydroxyl radical·OH with a high efficiency was extracted from Oyster shell at an extraction rate of 2.49%.It was found for the first time that this active substance may scavenge ·OH with the efficiency far higher than that of vitamin C.This active substance may scavenge also superoxide radical(O2-·)although the scavenging efficiency is far lower than that of vitamin C.Infrared spectrometry and routine chemical analysis primarily reveal that this active substance belongs to glycoprotein.

  3. High resolution neutron imaging capabilities at BOA beamline at Paul Scherrer Institut

    Energy Technology Data Exchange (ETDEWEB)

    Tremsin, A.S., E-mail: ast@ssl.berkeley.edu [Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720 (United States); Morgano, M.; Panzner, T.; Lehmann, E.; Filgers, U. [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Vallerga, J.V.; McPhate, J.B.; Siegmund, O.H.W. [Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720 (United States); Feller, W.B. [NOVA Scientific, Inc., 10 Picker Rd., Sturbridge, MA 01566 (United States)

    2015-06-01

    The cold neutron spectrum of the Beamline for neutron Optics and other Applications (BOA) at Paul Scherrer Institut enables high contrast neutron imaging because neutron cross sections for many materials increase with neutron wavelength. However, for many neutron imaging applications, spatial resolution can be as important as contrast. In this paper the neutron transmission imaging capabilities of an MCP/Timepix detector installed at the BOA beamline are presented, demonstrating the possibilities for studying sub-20 µm features in various samples. In addition to conventional neutron radiography and microtomography, the high degree of neutron polarization at the BOA beamline can be very attractive for imaging of magnetic fields, as demonstrated by our measurements. We also show that a collimated cold neutron beamline combined with a high resolution detector can produce image artifacts, (e.g. edge enhancements) due to neutron refraction and scattering. The results of our experiments indicate that the BOA beamline is a valuable addition to neutron imaging facilities, providing improved and sometimes unique capabilities for non-destructive studies with cold neutrons.

  4. Raman spectroscopy

    Science.gov (United States)

    Raman spectroscopy has gained increased use and importance in recent years for accurate and precise detection of physical and chemical properties of food materials, due to the greater specificity and sensitivity of Raman techniques over other analytical techniques. This book chapter presents Raman s...

  5. Liquid nitrogen cooled integrated power electronics module with high current carrying capability and lower on resistance

    Science.gov (United States)

    Ye, Hua; Lee, Changwoo; Simon, Randy W.; Haldar, Pradeep; Hennessy, Michael J.; Mueller, Eduard K.

    2006-11-01

    This letter presents the development of high-performance integrated cryogenic power modules, where both driver components and power metal-oxide semiconductor field-effect transistors are integrated in a single package, to be used in a 50kW prototype cryogenic inverter operating at liquid nitrogen temperature. The authors have demonstrated a compact high-voltage, cryogenic integrated power module that exhibited more than 14 times improvement in on-resistance and continuous current carrying capability exceeding 40A. The modules are designed to operate at liquid nitrogen temperature with extreme thermal cycling. The power electronic modules are necessary components that provide control and switching for second generation, yttrium barium copper oxide-based high temperature superconductor devices including cables, motors, and generators.

  6. Raman active high energy excitations in URu{sub 2}Si{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Buhot, Jonathan [Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot - Paris 7, Bât. Condorcet, 75205 Paris Cedex 13 (France); High Field Magnet Laboratory (HFML - EMFL), Institute for Molecules and Materials, Radboud University, Toernooiveld 7, 6525 ED Nijmegen (Netherlands); Gallais, Yann; Cazayous, Maximilien; Sacuto, Alain [Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot - Paris 7, Bât. Condorcet, 75205 Paris Cedex 13 (France); Piekarz, Przemysław [Institute of Nuclear Physics, Polish Academy of Sciences, 31-342 Krakòw (Poland); Lapertot, Gérard [Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble (France); CEA, INAC-SPSMS, F-38000 Grenoble (France); Aoki, Dai [Université Grenoble Alpes, INAC-SPSMS, F-38000 Grenoble (France); CEA, INAC-SPSMS, F-38000 Grenoble (France); Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Méasson, Marie-Aude, E-mail: marie-aude.measson@univ-paris-diderot.fr [Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot - Paris 7, Bât. Condorcet, 75205 Paris Cedex 13 (France)

    2017-02-01

    We have performed Raman scattering measurements on URu{sub 2}Si{sub 2} single crystals on a large energy range up to ∼1300 cm{sup −1} and in all the Raman active symmetries as a function of temperature down to 15 K. A large excitation, active only in the E{sub g} symmetry, is reported. It has been assigned to a crystal electric field excitation on the Uranium site. We discuss how this constrains the crystal electric field scheme of the Uranium ions. Furthermore, three excitations in the A{sub 1g} symmetry are observed. They have been associated to double Raman phonon processes consistently with ab initio calculations of the phonons dispersion.

  7. Experimental and theoretical investigation of pressure-dependent Raman spectra of triaminotrinitrobenzene (TATB) at high pressures

    Science.gov (United States)

    Landerville, Aaron C.; Crowhurst, Jonathan C.; Grant, Christian D.; Zaug, Joseph M.; Oleynik, Ivan

    2017-01-01

    The experimental pressure dependent Raman spectra of triamino-trinitrobenzene (TATB) are determined up to 24.5 GPa, and compared with those obtained using density functional theory (DFT) up to 27 GPa. The density functional theory calculations include the Grimme empirical van der Waals correction, as well as corrections for both thermal and zero-point energy contributions to pressure. DFT-predicted crystal structure of TATB at ambient conditions, the equation of state, and Raman spectra up to 24.5 GPa are in good agreement with experiment. Pressure-dependence of specific vibrational modes is discussed in detail. Further, the comparison of experimental and calculated Raman spectra of TATB offers evidence that no first-order polymorphic phase transition occurs at least up to 27 GPa.

  8. Effect of High Pressure on the Molecular Structure and π-Electrons Delocalization of Canthaxanthin as Revealed by Raman Spectra

    Directory of Open Access Journals (Sweden)

    Shun-li Ou-Yang

    2015-01-01

    Full Text Available The effect of high pressure on the molecular structure and π-electron delocalization of canthaxanthin was studied by in situ resonance Raman spectroscopy. Changes in the characteristic band frequency and the pressure of canthaxanthin were described. The effect of pressure on π-electron delocalization was also discussed. Results show that the characteristic bands of canthaxanthin increase and reach high wavenumbers. The correlations between Raman frequency of the three main bands and pressure are listed as follows: ν1(C=C = 3.43P + 1512.3, ν2(C-C = 3.29P + 1156.1, and ν3(CH3 = 2.16P + 1006.3. The frequency multiplication of canthaxanthin changes as pressure is altered. The pressure effect on the ν1(C=C mode is more susceptible than on the ν2(C-C mode, which can be explained by the fact that the β-ring twists to a larger angle from the plane of the conjugated main chain under high pressure, leading to a lower degree of the π-electrons delocalization. The Raman spectra are recovered after the compression-decompression cycle indicating the canthaxanthin has no evident phase change under our experimental conditions.

  9. Development of in-aquifer heat testing for high resolution subsurface thermal-storage capability characterisation

    Science.gov (United States)

    Seibertz, Klodwig Suibert Oskar; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2016-03-01

    The ongoing transition from fossil fuels to alternative energy source provision has resulted in increased geothermal uses as well as storage of the shallow subsurface. Existing approaches for exploration of shallow subsurface geothermal energy storage often lack the ability to provide information concerning the spatial variability of thermal storage parameters. However, parameter distributions have to be known to ensure that sustainable geothermal use of the shallow subsurface can take place - especially when it is subject to intensive usage. In this paper, we test a temperature decay time approach to obtain in situ, direct, qualitative, spatial high-resolution information about the distribution of thermal storage capabilities of the shallow subsurface. To achieve this, temperature data from a high-resolution Fibre-Optic-Distributed-Temperature-Sensing device, as well as data from conventional Pt100-temperature-sensors were collected during a heat injection test. The latter test was used to measure the decay time of temperature signal dissipation of the subsurface. Signal generation was provided by in-aquifer heating with a temperature self-regulating electric heating cable. Heating was carried out for 4.5 days. After this, a cooling period of 1.5 weeks was observed. Temperature dissipation data was also compared to Direct-Push-derived high-resolution (hydro-)geological data. The results show that besides hydraulic properties also the bedding and compaction state of the sediment have an impact on the thermal storage capability of the saturated subsurface. The temperature decay time approach is therefore a reliable method for obtaining information regarding the qualitative heat storage capability of heterogeneous aquifers for the use with closed loop system geothermal storage systems. Furthermore, this approach is advantageous over other commonly used methods, e.g. soil-sampling and laboratory analysis, as even small changes in (hydro-)geological properties lead to

  10. High-rate/high-temperature capability of a single-layer zicar-separator nickel-hydrogen cell

    Science.gov (United States)

    Wheeler, James R.

    1995-01-01

    A 50 Ampere-hour nickel-hydrogen cell with a single-layer Zircar separator stack design was fully charged and then discharged at a 2C current rate to an end voltage of 1 volt. This extreme test resulted in high temperatures which were recorded at three locations on the cell, i.e., the cell wall, the boss (barrel of the compression seal), and a terminal. The results provide new information about the high-temperature and high-discharge-rate capabilities of nickel-hydrogen cells. This information also adds to the growing data base for single-layer zirconium-oxide-cloth (Zircar) separator cell designs.

  11. High efficiency supercontinuum generation using ultra-long Raman fiber cavities.

    Science.gov (United States)

    El-Taher, Atalla E; Ania-Castañón, Juan D; Karalekas, Vassilis; Harper, Paul

    2009-09-28

    Supercontinuum generation in a multi-fiber ultra-long Raman fiber laser cavity is experimentally investigated for the first time. We demonstrate significantly enhanced spectral flatness and supercontinuum generation efficiency using only conventional single mode silica fiber. With a pump power of only 1.63W a approximately 15 dB bandwidth >260 nm wide (from 1440 to >1700 nm) supercontinuum source is reported with a flatness of nm using an optimised hybrid TW/HNLF cavity. We address the dependence of the supercontinuum spectrum on the input pump power and ultra-long Raman cavity.

  12. SERS imaging of cell-surface biomolecules metabolically labeled with bioorthogonal Raman reporters.

    Science.gov (United States)

    Xiao, Ming; Lin, Liang; Li, Zefan; Liu, Jie; Hong, Senlian; Li, Yaya; Zheng, Meiling; Duan, Xuanming; Chen, Xing

    2014-08-01

    Live imaging of biomolecules with high specificity and sensitivity as well as minimal perturbation is essential for studying cellular processes. Here, we report the development of a bioorthogonal surface-enhanced Raman scattering (SERS) imaging approach that exploits small Raman reporters for visualizing cell-surface biomolecules. The cells were cultured and imaged by SERS microscopy on arrays of Raman-enhancing nanoparticles coated on silicon wafers or glass slides. The Raman reporters including azides, alkynes, and carbondeuterium bonds are small in size and spectroscopically bioorthogonal (background-free). We demonstrated that various cell-surface biomolecules including proteins, glycans, and lipids were metabolically incorporated with the corresponding precursors bearing a Raman reporter and visualized by SERS microscopy. The coupling of SERS microscopy with bioorthogonal Raman reporters expands the capabilities of live-cell microscopy beyond the modalities of fluorescence and label-free imaging.

  13. Development of manufacturing capability for high-concentration, high-efficiency silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sinton, R.A.; Verlinden, P.J.; Crane, R.A.; Swanson, R.N. [SunPower Corp., Sunnyvale, CA (United States)

    1996-10-01

    This report presents a summary of the major results from a program to develop a manufacturable, high-efficiency silicon concentrator solar cell and a cost-effective manufacturing facility. The program was jointly funded by the Electric Power Research Institute, Sandia National Laboratories through the Concentrator Initiative, and SunPower Corporation. The key achievements of the program include the demonstration of 26%-efficient silicon concentrator solar cells with design-point (20 W/cm{sup 2}) efficiencies over 25%. High-performance front-surface passivations; that were developed to achieve this result were verified to be absolutely stable against degradation by 475 days of field exposure at twice the design concentration. SunPower demonstrated pilot production of more than 1500 of these cells. This cell technology was also applied to pilot production to supply 7000 17.7-cm{sup 2} one-sun cells (3500 yielded wafers) that demonstrated exceptional quality control. The average efficiency of 21.3% for these cells approaches the peak efficiency ever demonstrated for a single small laboratory cell within 2% (absolute). Extensive cost models were developed through this program and calibrated by the pilot-production project. The production levels achieved indicate that SunPower could produce 7-10 MW of concentrator cells per year in the current facility based upon the cell performance demonstrated during the program.

  14. Red-detuned, high-intensity, short-duration sweet spot for impulsive X-ray Raman excitation in atoms

    CERN Document Server

    Ware, Matthew R; Haxton, Daniel J

    2016-01-01

    Impulsive X-ray Raman excitations of Lithium, Neon, and Sodium are calculated using the Multiconfiguration Time-Dependent Hartree-Fock method. Using linearly polarized laser pulses without chirp, we determine the optimum central frequency, intensity, and duration for maximum population transfer to valence excited states. We demonstrate the existence of two "sweet spots" for optimum population transfer, either of which, depending on the system, may be superior. The "red-detuned hypothesis" is the proposition that population transfer can be maximized by nonresonant Raman transitions, red-detuned below K-edge, because such detuning minimizes core-excited populations and ionization loss. We find that this hypothesis is verified in the case of Neon -- for Neon, the global optimum for population transfer occurs at high intensity (8 $\\times$ 10$^{19}$ W cm$^{-2}$), short duration (82as full-width-at-half-maximum), and 24eV red-detuned from the K-edge.

  15. High-pressure Raman scattering of CaWO₄ up to 46.3 GPa: evidence of a new high-pressure phase.

    Science.gov (United States)

    Botella, Pablo; Lacomba-Perales, Raúl; Errandonea, Daniel; Polian, Alain; Rodríguez-Hernández, Placida; Muñoz, Alfonso

    2014-09-15

    The high-pressure behavior of CaWO4 was analyzed at room temperature by Raman spectroscopy. Pressure was generated using a diamond-anvil cell and Ne as pressure-transmitting medium. The pressure range of previous studies has been extended from 23.4 to 46.3 GPa. The experiments reveal the existence of two reversible phase transitions. The first one occurs from the tetragonal scheelite structure to the monoclinic fergusonite structure and is observed at 10 GPa. The onset of a previously unknown second transition is found at 33.4 GPa. The two high-pressure phases coexist up to 39.4 GPa. The Raman spectra measured for the low-pressure phase and the first high-pressure phase are consistent with previous studies in the pressure range where comparison is possible. The pressure dependence of all the Raman-active modes is reported for different phases. We also report total-energy and lattice-dynamics calculations, which determine the occurrence of two phase transitions in the pressure range covered by the experiments. The first transition is in full agreement with experiments (scheelite-to-fergusonite). According to calculations, the second-highest pressure phase has an orthorhombic structure (space group Cmca). Details of this structure, its Raman modes, and its electronic band structure are given. The reliability of the reported results is supported by the consistency between the theoretical and experimental values obtained for transition pressures, phonon frequencies, and phonon pressure coefficients.

  16. New insights into the molecular mechanisms of thrombosis from high resolution surface enhanced Raman microscopy

    Science.gov (United States)

    Keyes, Tia E.; Leane, Deirdre; Forster, Robert J.; Moran, Niamh; Kenny, Dermot

    2005-06-01

    Occlusion of a blood vessel due to thrombosis can reduce or completely stop blood supply to different tissues or organs with the clinical consequences of myocardial infarction or stroke. Platelets are the cellular component which initiate thrombus formation, they activate in response to a variety of signals, such as interactions with a damaged blood vessel. αIIbβ3 is a membrane bound integrin protein responsible for regulating adhesion of the activated platelet to damaged blood vessels. It exists in both activated and non-activated states displaying high and low affinity respectively for ligands such as fibrinogen. αIIbβ3 determines the "stickiness" of the blood platelet and is therefore, a logical target for therapeutic measures to control thrombus formation. During the past decade considerable progress has been made to identify the role of the αIIbβ3 complex in platelet-mediated thrombus formation and the structure of αIIbβ3 has been extrapolated from the crystal structure of related integrins. However, despite these advances, the bimolecular mechanisms underlying the activation of αIIbβ3 remain poorly understood. In this contribution, we describe methodologies of deriving surface enhanced Raman spectroscopy of αIIbβ3 on nanostructured metal surfaces, fabricated by a number of methods. We compare activation of αIIbβ3 by SERS using a range of known activation conditions including Mn(II), EDTA and dithiotheritol (DTT). By studying the behaviour of the disulfide and CS marker vibrations in the spectral region 400 to 800 cm-1 using SERS we confirm that activation results in significant conformational change in the protein, and most interestingly, that the response is not the same for every agonist. This mechanistic difference has implications for the biochemical study of this protein (and indeed for understanding the role of this integrin in response to different agonists).

  17. High-pressure Raman investigations of phase transformations in pentaerythritol (C(CH sub 2 OH) sub 4)

    CERN Document Server

    Bhattacharya, T

    2002-01-01

    Our high-pressure Raman scattering experiments on pentaerythritol (C(CH sub 2 OH) sub 4) show that this compound undergoes at least three phase transformations up to 25 GPa. Splitting of various modes at approx 6.3, approx 8.2 and 10 GPa suggests that these phase transformations result in lowering of crystalline symmetry. A very small discontinuous change in slope of most of the Raman-active modes is observed at 0.3 GPa. However, no other signature of a phase transition was observed at this pressure. The observed correlation of the pressures for the onset of the two phase transformations with the limiting values of the distances between various non-bonded atoms in the parent phase suggests that the molecular rearrangements across the phase transformations are not very drastic. In addition, our earlier Fourier transform infrared and present Raman investigations indicate that high-pressure compression leads to increase in strength of the hydrogen bond present in this compound.

  18. High enhancement factor of Au nano triangular prism structure for surface enhanced coherent anti-Stokes Raman scattering

    Science.gov (United States)

    Zhang, Zuyin; Song, Guofeng

    2017-02-01

    Coherent anti-Stokes Raman scattering spectroscopy (CARS) is a well-known detecting tool in biosensing and nonlinear spectroscopy. It can provide a non-invasive alternative without the need for exogenous labels, while the enhancement factor for surface plasmon resonances (SPR) are extensively used to increase the local field close to the oscillators and which can obtain high enhancement. In this work, we investigate the enhancement factor of our structure for surface-enhanced coherent anti-Stokes Raman scattering. The absorption spectrum of the structure has been studied, a wide range of absorption has been realized. The enhancement can be as high as 10{16} over standard CARS. Our design is very useful for improving the enhancement factor of surface-enhanced coherent anti-Stokes Raman scattering. Project supported by the National Key Research Program of China (No. 2011ZX01015-001) and the National Basic Research Program of China (Nos. 2011CBA00608, 2012CB619203, 2015CB351902, 2015CB932402).

  19. Probing electronic lifetimes and phonon anharmonicities in high-quality chemical vapor deposited graphene by magneto-Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Neumann, Christoph, E-mail: cneumann@physik.rwth-aachen.de; Stampfer, Christoph [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Peter Grünberg Institute (PGI-9), Forschungszentrum Jülich, 52425 Jülich (Germany); Halpaap, Donatus; Banszerus, Luca; Schmitz, Michael; Beschoten, Bernd [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Reichardt, Sven [JARA-FIT and 2nd Institute of Physics, RWTH Aachen University, 52074 Aachen (Germany); Physics and Materials Science Research Unit, Université du Luxembourg, 1511 Luxembourg (Luxembourg); Watanabe, Kenji; Taniguchi, Takashi [National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-12-07

    We present a magneto-Raman study on high-quality single-layer graphene grown by chemical vapor deposition (CVD) that is fully encapsulated in hexagonal boron nitride by a dry transfer technique. By analyzing the Raman D, G, and 2D peaks, we find that the structural quality of the samples is comparable with state-of-the-art exfoliated graphene flakes. From B-field dependent Raman measurements, we extract the broadening and associated lifetime of the G peak due to anharmonic effects. Furthermore, we determine the decay width and lifetime of Landau level (LL) transitions from magneto-phonon resonances as a function of laser power. At low laser power, we find a minimal decay width of 140 cm{sup −1} highlighting the high electronic quality of the CVD-grown graphene. At higher laser power, we observe an increase of the LL decay width leading to a saturation, with the corresponding lifetime saturating at a minimal value of 18 fs.

  20. Modeling of a stair-climbing wheelchair mechanism with high single-step capability.

    Science.gov (United States)

    Lawn, Murray J; Ishimatsu, Takakazu

    2003-09-01

    In the field of providing mobility for the elderly and disabled, the aspect of dealing with stairs continues largely unresolved. This paper focuses on presenting the development of a stair-climbing wheelchair mechanism with high single-step capability. The mechanism is based on front and rear wheel clusters connected to the base (chair) via powered linkages so as to permit both autonomous stair ascent and descent in the forward direction, and high single-step functionality for such as direct entry to and from a van. Primary considerations were inherent stability, provision of a mechanism that is physically no larger than a standard powered wheelchair, aesthetics, and being based on readily available low-cost components.

  1. Neutron irradiation damage of nuclear graphite studied by high-resolution transmission electron microscopy and Raman spectroscopy

    Science.gov (United States)

    Krishna, R.; Jones, A. N.; McDermott, L.; Marsden, B. J.

    2015-12-01

    Nuclear graphite components are produced from polycrystalline artificial graphite manufacture from a binder and filler coke with approximately 20% porosity. During the operational lifetime, nuclear graphite moderator components are subjected to fast neutron irradiation which contributes to the change of material and physical properties such as thermal expansion co-efficient, young's modulus and dimensional change. These changes are directly driven by irradiation-induced changes to the crystal structure as reflected through the bulk microstructure. It is therefore of critical importance that these irradiation changes and there implication on component property changes are fully understood. This work examines a range of irradiated graphite samples removed from the British Experimental Pile Zero (BEPO) reactor; a low temperature, low fluence, air-cooled Materials Test Reactor which operated in the UK. Raman spectroscopy and high-resolution transmission electron microscopy (HRTEM) have been employed to characterise the effect of increased irradiation fluence on graphite microstructure and understand low temperature irradiation damage processes. HRTEM confirms the structural damage of the crystal lattice caused by irradiation attributed to a high number of defects generation with the accumulation of dislocation interactions at nano-scale range. Irradiation-induced crystal defects, lattice parameters and crystallite size compared to virgin nuclear graphite are characterised using selected area diffraction (SAD) patterns in TEM and Raman Spectroscopy. The consolidated 'D'peak in the Raman spectra confirms the formation of in-plane point defects and reflected as disordered regions in the lattice. The reduced intensity and broadened peaks of 'G' and 'D' in the Raman and HRTEM results confirm the appearance of turbulence and disordering of the basal planes whilst maintaining their coherent layered graphite structure.

  2. In Site Analysis of a High Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

    Science.gov (United States)

    Cooper, John; Aust, Jeffrey F.; Wise, Kent L.; Jensen, Brian J.

    1999-01-01

    The vibrational spectrum of a high temperature (330 C) polymerization reaction was successfully monitored in real time using a modulated fiber-optic FT-Raman spectrometer. A phenylethynyl terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

  3. A new active array MST radar system with enhanced capabilities for high resolution atmospheric observations

    Science.gov (United States)

    Durga rao, Meka; Jayaraman, Achuthan; Patra, Amit; Venkat Ratnam, Madineni; Narayana Rao, T.; Kamaraj, Pandian; Jayaraj, Katta; Kmv, Prasad; Kamal Kumar, J.; Raghavendra, J.; Prasad, T. Rajendra; Thriveni, A.; Yasodha, Polisetti

    2016-07-01

    A new version of the 53-MHz MST Radar, using the 1024 solid state Transmit-Receive Modules (TRM), necessary feeder network, multi-channel receiver and a modified radar controller has been established using the existing antenna array of 1024 crossed Yagis. The new system has been configured for steering the beam on a pulse-to-pulse basis in all 360o azimuth and 20o zenith angle, providing enhanced capability to study the Mesosphere-Stratosphere-Troposphere and Ionosphere. The multi channel receiver system has been designed for Spaced Antenna (SA) and Interferometry/ Iamging applications. The new system has also been configured for radiating in circular polarization for its application in the Ionosphere Incoherent Scatter mode. The new active array MST radar at Very-High-Frequency (53-MHz) located at Gadanki (13.45°N, 79.18°E), a tropical station in India, will be used to enhance the observations of winds, turbulence during the passage of convective events over the radar site as deep convection occurs very often at tropical latitudes. The new configuration with enhanced average power, beam agility with multi-channel experiments will be a potential source for studying middle atmosphere and ionosphere. In this paper, we present the system configuration, new capabilities and the first results obtained using the new version of the MST Radar.

  4. High-rate capability of zinc anodes in alkaline primary cells

    Science.gov (United States)

    Huot, Jean-Yves; Malservisi, Martin

    This work is devoted to the electrochemical aspects of high-power testing of primary alkaline LR6 ("AA") cells and to the factors influencing cell performance, namely the corresponding zinc anode behaviour under such high-rate conditions. The influence of the high-rate testing regime, such as the discharge mode and the end-potential, on zinc utilisation in alkaline cells has been monitored and its behaviour has been isolated by means of a pseudo-reference electrode. As anticipated, anode formulation, including zinc alloy composition and size distribution, is found to affect the cell's discharge curve and the corresponding zinc electrode potential and utilisation. The effects of these parameters on the discharge curve are discussed in terms of three stages of discharge. Finally, the high-rate capability of commercial LR6 cells is analysed in terms of zinc anode formulation. It was concluded that zinc electrode polarisation is very small and is relatively independent of manufacturer, of zinc anode formulation and of zinc alloying. On the other hand, metallic zinc utilisation remains very low under high-rate conditions.

  5. The Hydrothermal Diamond Anvil Cell (HDAC) for raman spectroscopic studies of geologic fluids at high pressures and temperatures

    Science.gov (United States)

    Schmidt, Christian; Chou, I-Ming; Dubessy, Jean; Caumon, Marie-Camille; Pérez, Fernando Rull

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ⬚~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  6. Chapter 7: The hydrothermal diamond anvil cell (HDAC) for Raman spectroscopic studies of geological fluids at high pressures and temperatures

    Science.gov (United States)

    Schmidt, Christian; Chou, I-Ming; Dubessy, J.; Caumon, M.-C.; Rull, F.

    2012-01-01

    In this chapter, we describe the hydrothermal diamond-anvil cell (HDAC), which is specifically designed for experiments on systems with aqueous fluids to temperatures up to ~1000ºC and pressures up to a few GPa to tens of GPa. This cell permits optical observation of the sample and the in situ determination of properties by ‘photon-in photon-out’ techniques such as Raman spectroscopy. Several methods for pressure measurement are discussed in detail including the Raman spectroscopic pressure sensors a-quartz, berlinite, zircon, cubic boron nitride (c-BN), and 13C-diamond, the fluorescence sensors ruby (α-Al2O3:Cr3+), Sm:YAG (Y3Al5O12:Sm3+) and SrB4O7:Sm2+, and measurements of phase-transition temperatures. Furthermore, we give an overview of published Raman spectroscopic studies of geological fluids to high pressures and temperatures, in which diamond anvil cells were applied.

  7. Investigating the Mobility of Light Autonomous Tracked Vehicles using a High Performance Computing Simulation Capability

    Science.gov (United States)

    Negrut, Dan; Mazhar, Hammad; Melanz, Daniel; Lamb, David; Jayakumar, Paramsothy; Letherwood, Michael; Jain, Abhinandan; Quadrelli, Marco

    2012-01-01

    This paper is concerned with the physics-based simulation of light tracked vehicles operating on rough deformable terrain. The focus is on small autonomous vehicles, which weigh less than 100 lb and move on deformable and rough terrain that is feature rich and no longer representable using a continuum approach. A scenario of interest is, for instance, the simulation of a reconnaissance mission for a high mobility lightweight robot where objects such as a boulder or a ditch that could otherwise be considered small for a truck or tank, become major obstacles that can impede the mobility of the light autonomous vehicle and negatively impact the success of its mission. Analyzing and gauging the mobility and performance of these light vehicles is accomplished through a modeling and simulation capability called Chrono::Engine. Chrono::Engine relies on parallel execution on Graphics Processing Unit (GPU) cards.

  8. Mechanisms, Capabilities, and Applications of High-Resolution Electrohydrodynamic Jet Printing.

    Science.gov (United States)

    Onses, M Serdar; Sutanto, Erick; Ferreira, Placid M; Alleyne, Andrew G; Rogers, John A

    2015-09-01

    This review gives an overview of techniques used for high-resolution jet printing that rely on electrohydrodynamically induced flows. Such methods enable the direct, additive patterning of materials with a resolution that can extend below 100 nm to provide unique opportunities not only in scientific studies but also in a range of applications that includes printed electronics, tissue engineering, and photonic and plasmonic devices. Following a brief historical perspective, this review presents descriptions of the underlying processes involved in the formation of liquid cones and jets to establish critical factors in the printing process. Different printing systems that share similar principles are then described, along with key advances that have been made in the last decade. Capabilities in terms of printable materials and levels of resolution are reviewed, with a strong emphasis on areas of potential application.

  9. Porous Azo-Bridged Porphyrin-Phthalocyanine Network with High Iodine Capture Capability.

    Science.gov (United States)

    Li, Hui; Ding, Xuesong; Han, Bao-Hang

    2016-08-08

    We report a highly efficient iodine adsorbent achieved by rational design of a porous azo-bridged porphyrin-phthalocyanine network (AzoPPN), which was synthesized by a catalyst-free coupling reaction between free-base 5,10,15,20-tetrakis(4-nitrophenyl)-porphyrin and nickel tetraaminophthlocyanine. AzoPPN has a permanent porous structure and plenty of porphyrin and phthalocyanine units in the skeleton as effective sorption sites. It displays excellent adsorption of iodine vapor up to 290 wt. % and also shows remarkable capability as adsorbent for iodine in solution. This strategy of combining physisorption with chemisorption in one adsorbent will pave the way for the development of new materials for iodine capture. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. MBARI Mapping AUV: A High-Resolution Deep-Ocean Seafloor Mapping Capability

    Science.gov (United States)

    Kirkwood, W. J.; Caress, D. W.; Thomas, H.; McEwen, R.; Henthorn, R.; Sibenac, M.; McGill, P.; Hamilton, A.; Shane, F.; Thompson, D.; Jensen, S.; Salamy, K.

    2005-12-01

    The Monterey Bay Aquarium Research Institute (MBARI) has developed an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. The Mapping AUV is powered by 6 kWhr of Li-polymer batteries, providing a mission duration of 12 hours at a typical speed of 1.5 m/s. All components of the vehicle are rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. The sonar package can also be mounted on ROV Ventana, allowing surveys at altitudes less than 10 m at topographically challenging sites. The vehicle was assembled and underwent initial tests during 2004. During 2005 we have commenced science survey operations while completing the integration and testing of the complete suite of sensors and systems. MBARI is now using this capability in both autonomous and ROV-mounted surveys to observe the changing morphology of dynamic systems such as submarine canyons and active slumps, to map deep-water benthic habitats at resolutions comparable to ROV and submersible observations, to provide basemaps for ROV dives, and to provide high resolution bathymetry and subbottom profiles in support of seafloor observatory installations.

  11. High-sensitivity molecular sensing using hollow-core photonic crystal fiber and surface-enhanced Raman scattering.

    Science.gov (United States)

    Yang, Xuan; Shi, Chao; Wheeler, Damon; Newhouse, Rebecca; Chen, Bin; Zhang, Jin Z; Gu, Claire

    2010-05-01

    A high-sensitivity molecular sensor using a hollow-core photonic crystal fiber (HCPCF) based on surface-enhanced Raman scattering (SERS) has been experimentally demonstrated and theoretically analyzed. A factor of 100 in sensitivity enhancement is shown in comparison to direct sampling under the same conditions. With a silver nanoparticle colloid as the SERS substrate and Rhodamine 6G as a test molecule, the lowest detectable concentration is 10(-10) M with a liquid-core photonic crystal fiber (LCPCF) probe, and 10(-8) M for direct sampling. The high sensitivity provided by the LCPCF SERS probe is promising for molecular detection in various sensing applications.

  12. Variable high-resolution color CCD camera system with online capability for professional photo studio application

    Science.gov (United States)

    Breitfelder, Stefan; Reichel, Frank R.; Gaertner, Ernst; Hacker, Erich J.; Cappellaro, Markus; Rudolf, Peter; Voelk, Ute

    1998-04-01

    Digital cameras are of increasing significance for professional applications in photo studios where fashion, portrait, product and catalog photographs or advertising photos of high quality have to be taken. The eyelike is a digital camera system which has been developed for such applications. It is capable of working online with high frame rates and images of full sensor size and it provides a resolution that can be varied between 2048 by 2048 and 6144 by 6144 pixel at a RGB color depth of 12 Bit per channel with an also variable exposure time of 1/60s to 1s. With an exposure time of 100 ms digitization takes approx. 2 seconds for an image of 2048 by 2048 pixels (12 Mbyte), 8 seconds for the image of 4096 by 4096 pixels (48 Mbyte) and 40 seconds for the image of 6144 by 6144 pixels (108 MByte). The eyelike can be used in various configurations. Used as a camera body most commercial lenses can be connected to the camera via existing lens adaptors. On the other hand the eyelike can be used as a back to most commercial 4' by 5' view cameras. This paper describes the eyelike camera concept with the essential system components. The article finishes with a description of the software, which is needed to bring the high quality of the camera to the user.

  13. Evidence of High Ice Supersaturation in Cirrus Clouds Using ARM Raman Lidar Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Comstock, Jennifer M.; Ackerman, Thomas P.; Turner, David D.

    2004-06-05

    Water vapor amounts in the upper troposphere are crucial to understanding the radiative feedback of cirrus clouds on the Earth’s climate. We use a unique, year-long dataset of water vapor mixing ratio inferred from ground-based Raman lidar measurements to study the role of ice supersaturation in ice nucleation processes. We find that ice supersaturation occurs 31% of the time in over 300,000 data points. We also examine the distribution of ice supersaturation with height and find that in the uppermost portion of a cloud layer, the air is ice supersaturated 43% of the time. These measurements show that large ice supersaturation is common in cirrus clouds, which supports the theory of ice forming homogeneously. Given the continuous nature of these Raman lidar measurements, our results have important implications for studying ice nucleation processes using cloud microphysical models.

  14. ARM Raman Lidar Measurements of High Ice Supersaturation in Cirrus Clouds

    Energy Technology Data Exchange (ETDEWEB)

    Comstock, Jennifer M.; Ackerman, Thomas P.; Turner, David D.

    2004-09-01

    Water vapor amounts in the upper troposphere are crucial to understanding the radiative feedback of cirrus clouds on the Earth's climate. We use a unique, year-long dataset of water vapor mixing ratio inferred from ground-based Raman lidar measurements to study the role of ice supersaturation in ice nucleation processes. We find that ice supersaturation occurs 31% of the time in over 300,000 data points. We also examine the distribution of ice supersaturation with height and find that in the uppermost portion of a cloud layer, the air is ice supersaturated 43% of the time. These measurements show that large ice supersaturation is common in cirrus clouds, which supports the theory of ice forming homogeneously. Given the continuous nature of these Raman lidar measurements, our results have important implications for studying ice nucleation processes using cloud microphysical models.

  15. [A study of phonon vibration like modes for aggregation structure in silicate melts by high temperature Raman spectrum].

    Science.gov (United States)

    Xu, Pei-Cang; Li, Ru-Bi; Shang, Tong-Ming; Zhou, Jian; Sun, Jian-Hua; You, Jing-Lin

    2010-05-01

    Silicate melts are special fractal dimension system that is metastable state of near-way order and far-way disorder. In this paper, the size of nanometer aggregation structure and the frequences of phonon vibration like mode in the low dimension silicate series (CaO-Al2O3-SiO2 and Na2-Al2O3-SiO2 series) synthesized via high temperature melting and sol gel methods were measured by means of small-angle X-ray scattering (SAXS), low wavenumber Raman spectrum (LWRS) and high temperature Raman spectrum (HTRS in situ measuring). The nanometer self-similarity aggregation structure(it's size is about a few nm to a few tens nm) and phonic phonon vibration like modes of low temperature silicate gel, high temperature silicate melts and it's quenching glasses phases were obtained. So a quantitative method by HTRS for measuring the aggregation size in the high temperature melts was established. The results showed that the aggregation size of the silicate melts is smaller at high temperature than at room temperature and the number of bridge oxygen in one Si-O tetrahedron in network structure units is decreasing at high temperature. This study work provides important theory and information for deliberating geochemistry characteristic, crystallization & evolution of natural magma and enhancing performance of low dimension silicate matelials.

  16. A flow cytometer for the measurement of Raman spectra.

    Science.gov (United States)

    Watson, Dakota A; Brown, Leif O; Gaskill, Daniel F; Naivar, Mark; Graves, Steven W; Doorn, Stephen K; Nolan, John P

    2008-02-01

    Multiparameter measurements in flow cytometry are limited by the broad emission spectra of fluorescent labels. By contrast, Raman spectra are notable for their narrow spectral features. To increase the multiparameter analysis capabilities of flow cytometry, we investigated the possibility of measuring Raman signals in a flow cytometry-based system. We constructed a Raman Spectral Flow Cytometer, substituting a spectrograph and CCD detector for the traditional mirrors, optical filters, and photomultiplier tubes. Excitation at 633 nm was provided by a HeNe laser, and forward-angle light scatter is used to trigger acquisition of complete spectra from individual particles. Microspheres were labeled with nanoparticle surface enhanced Raman scattering (SERS) tags and measured using the RSFC. Fluorescence and Raman spectra from labeled microspheres were acquired using the Raman Spectral Flow Cytometer. SERS spectral intensities were dependent on integration time, laser power, and detector pixel binning. Spectra from particles labeled with one each of four different SERS tags could be distinguished by either a virtual bandpass approach using commercial flow cytometry data analysis software or by principal component analysis. Raman flow cytometry opens up new possibilities for highly multiparameter and multiplexed measurements of cells and other particles using a simple optical design and a single detector and light source.

  17. High-pressure Raman study of mono-L-alaninium nitrate crystals

    Science.gov (United States)

    Soares, R. A.; Lima, R. J. C.; Façanha Filho, P. F.; Freire, P. T. C.; Lima, J. A.; da Silva Filho, J. G.

    2017-09-01

    Single-crystal samples of mono-L-alaninium nitrate, known for its non-linear optical properties, have been studied by Raman spectroscopy in a diamond-anvil cell up to pressures of 7.4 GPa. The data acquired in this study are consistent with the hypothesis that a phase transition takes place between 3.5 and 4.1 GPa, as suggested by the change of Raman profile in both the low wavenumber and the internal modes spectral regions. A detailed analysis of the vibrational properties in the wavenumber region below 130 cm-1 including the dependence of the wavenumber of the observed modes as a function of pressure as well a comparison with previous papers reporting the Raman spectra of the L-alanine is presented. Correlation between hydrogen bond at room pressure and the occurrence of the phase transition with pressure variation was proposed giving new insights about the problem. Upon decompression to ambient pressure the original spectra were recovered indicating that the phase transition is reversible.

  18. High-throughput Raman chemical imaging for evaluating food safety and quality

    Science.gov (United States)

    Qin, Jianwei; Chao, Kuanglin; Kim, Moon S.

    2014-05-01

    A line-scan hyperspectral system was developed to enable Raman chemical imaging for large sample areas. A custom-designed 785 nm line-laser based on a scanning mirror serves as an excitation source. A 45° dichroic beamsplitter reflects the laser light to form a 24 cm x 1 mm excitation line normally incident on the sample surface. Raman signals along the laser line are collected by a detection module consisting of a dispersive imaging spectrograph and a CCD camera. A hypercube is accumulated line by line as a motorized table moves the samples transversely through the laser line. The system covers a Raman shift range of -648.7-2889.0 cm-1 and a 23 cm wide area. An example application, for authenticating milk powder, was presented to demonstrate the system performance. In four minutes, the system acquired a 512x110x1024 hypercube (56,320 spectra) from four 47-mm-diameter Petri dishes containing four powder samples. Chemical images were created for detecting two adulterants (melamine and dicyandiamide) that had been mixed into the milk powder.

  19. Raman facility

    Data.gov (United States)

    Federal Laboratory Consortium — Raman scattering is a powerful light scattering technique used to diagnose the internal structure of molecules and crystals. In a light scattering experiment, light...

  20. MBARI Mapping AUV: A High-Resolution Deep Ocean Seafloor Mapping Capability

    Science.gov (United States)

    Caress, D. W.; Kirkwood, W. J.; Thomas, H.; McEwen, R.; Henthorn, R.; McGill, P.; Thompson, D.; Sibenac, M.; Jensen, S.; Shane, F.; Hamilton, A.

    2005-05-01

    The Monterey Bay Aquarium Research Institute (MBARI) is developing an autonomous seafloor mapping capability for deep ocean science applications. The MBARI Mapping AUV is a 0.53 m (21 in) diameter, 5.1 m (16.7 ft) long, Dorado-class vehicle designed to carry four mapping sonars. The primary sensor is a 200 kHz multibeam sonar producing swath bathymetry and sidescan. In addition, the vehicle carries 100 kHz and 410 kHz chirp sidescan sonars, and a 2-16 kHz sweep chirp subbottom profiler. Navigation and attitude data are obtained from an inertial navigation system (INS) incorporating a ring laser gyro and a 300 kHz Doppler velocity log (DVL). The vehicle also includes acoustic modem, ultra-short baseline navigation, and long-baseline navigation systems. The Mapping AUV is powered by 6 kWhr of Li-polymer batteries, providing expected mission duration of 12 hours at a typical speed of 1.5 m/s. All components of the vehicle are rated to 6000 m depth, allowing MBARI to conduct high-resolution mapping of the deep-ocean seafloor. The sonar package is also be mountable on ROV Ventana, allowing surveys at altitudes less than 20 m at topographically challenging sites. The vehicle was assembled and extensively tested during 2004; this year we are commencing operations for MBARI science projects while continuing the process of testing and integrating the complete suite of sensors and systems. MBARI is beginning to use this capability to observe the changing morphology of dynamic systems such as submarine canyons and active slumps, to map deep-water benthic habitats at resolutions comparable to ROV and submersible observations, to provide basemaps for ROV dives, and to provide high resolution bathymetry and subbottom profiles as part of a variety of projects requiring knowledge of the seafloor. We will present initial results from surveys in and around Monterey Canyon, including high resolution repeat surveys of four sites along the canyon axis.

  1. Fabrication of three-dimensional graphene foam with high electrical conductivity and large adsorption capability

    Science.gov (United States)

    Chen, Guiqiang; Liu, Yanxia; Liu, Fei; Zhang, Xiao

    2014-08-01

    A three-dimensional (3D), free-standing graphene foam was prepared by plasma-enhanced chemical vapor deposition on nickel-foam. The prepared graphene foam was found to consist of few-layered vertically-aligned graphene sheets with highly graphite structure. Owing to the 3D interconnected porous nanostructures, the graphene foam exhibited a high electrical conductivity of 125 S/cm and a large surface area of 625.4 cm2/g. For practical application, we prepared the graphene foam/epoxy composites showing a maximum conductivity of 196 S/m at 2.5 vol.% filler loading, and a rather low percolation threshold of 0.18 vol.%. Furthermore, the derived graphene oxide foam exhibited an excellent absorption capability (177.6 mg/g for As(V), 399.3 mg/g for Pb(II)) and recyclability (above 90% removal efficiency after five cycles) for the removal of heavy metal ions. The present study reveals that the multifunctional graphene foam may broaden the graphene-based materials for the applications in electrically conductive composites and environmental cleanup.

  2. Copper-Doped Titanium Dioxide Bronze Nanowires with Superior High Rate Capability for Lithium Ion Batteries.

    Science.gov (United States)

    Zhang, Yongquan; Meng, Yuan; Zhu, Kai; Qiu, Hailong; Ju, Yanming; Gao, Yu; Du, Fei; Zou, Bo; Chen, Gang; Wei, Yingjin

    2016-03-01

    Pristine and Cu-doped TiO2-B nanowires are synthesized by the microwave assisted hydrothermal method. The doped oxide exhibits a highly porous structure with a specific surface area of 160.7 m(2) g(-1). As evidenced by X-ray photoelectron spectroscopy and X-ray energy dispersive spectroscopy, around 2.0 atom % Cu(2+) cations are introduced into TiO2-B, which leads to not only a slightly expanded lattice network but also, more importantly, a modified electronic structure. The band gap of TiO2-B is reduced from 2.94 to 2.55 eV, resulting in enhanced electronic conductivity. Cyclic voltammetry and electrochemical impedance spectroscopy reveal improved electrochemical kinetic properties of TiO2-B due to the Cu doping. The doped nanowires show a specific capacity of 186.8 mAh g(-1) at the 10 C rate with a capacity retention of 64.3% after 2000 cycles. Remarkably, our material exhibits a specific capacity of 150 mAh g(-1) at the 60 C rate, substantiating its superior high rate capability for rechargeable lithium batteries.

  3. Ultralow power, high fill factor smart complementary metal oxide semiconductor image sensor with motion detection capability

    Science.gov (United States)

    Mahbod, Abbas; Karimiyan, Hossein

    2016-11-01

    Bandwidth saving, power consumption, and fill factor improvement are known as vitally important challenges image sensor designers face in order to accomplish high-performance imaging systems. This paper presents an ultralow power, high fill factor smart complementary metal oxide semiconductor (CMOS) image sensor with motion detection capability. In this efficient methodology, the amount of redundant data processed in unimportant frames has been reduced significantly, and therefore, the proposed imaging system consumes less power compared with counterpart imagers. Furthermore, a pixel structure is introduced that outputs two consecutive frame voltages in series, with the result that the pixel size is minimized and a higher fill factor is achieved. In order to simulate the image capturing procedure, a state-of-the-art approach based on MATLAB and HSPICE software is devised, which is another important achievement of this paper. The performance of this technique is demonstrated using a 64×64 pixel sensor designed in a 0.18-μm standard CMOS technology. The sensor chip consumes 0.2 mW of power while operating at 100 fps with a fill factor of 45%.

  4. Confocal Raman spectroscopic analysis of cross-linked ultra-high molecular weight polyethylene for application in artificial hip joints.

    Science.gov (United States)

    Pezzotti, Giuseppe; Kumakura, Tsuyoshi; Yamada, Kiyotaka; Tateiwa, Toshiyuki; Puppulin, Leonardo; Zhu, Wenliang; Yamamoto, Kengo

    2007-01-01

    Confocal spectroscopic techniques are applied to selected Raman bands to study the microscopic features of acetabular cups made of ultra-high molecular weight polyethylene (UHMWPE) before and after implantation in vivo. The micrometric lateral resolution of a laser beam focused on the polymeric surface (or subsurface) enables a highly resolved visualization of 2-D conformational population patterns, including crystalline, amorphous, orthorhombic phase fractions, and oxidation index. An optimized confocal probe configuration, aided by a computational deconvolution of the optical probe, allows minimization of the probe size along the in-depth direction and a nondestructive evaluation of microstructural properties along the material subsurface. Computational deconvolution is also attempted, based on an experimental assessment of the probe response function of the polyethylene Raman spectrum, according to a defocusing technique. A statistical set of high-resolution microstructural data are collected on a fully 3-D level on gamma-ray irradiated UHMWPE acetabular cups both as-received from the maker and after retrieval from a human body. Microstructural properties reveal significant gradients along the immediate material subsurface and distinct differences are found due to the loading history in vivo, which cannot be revealed by conventional optical spectroscopy. The applicability of the confocal spectroscopic technique is valid beyond the particular retrieval cases examined in this study, and can be easily extended to evaluate in-vitro tested components or to quality control of new polyethylene brands. Confocal Raman spectroscopy may also contribute to rationalize the complex effects of gamma-ray irradiation on the surface of medical grade UHMWPE for total joint replacement and, ultimately, to predict their actual lifetime in vivo.

  5. Development and in vivo testing of a high frequency endoscopic Raman spectroscopy system for potential applications in the detection of early colonic neoplasia.

    Science.gov (United States)

    Short, Michael A; Wang, Wenbo; Tai, Isabella T; Zeng, Haishan

    2016-01-01

    The objective of this study was to build and test an adjunct system to a colonoscope for in vivo measurement of Raman spectra from colon tissue for potentially improving the detection of early cancers. The novelty of this system was that low cost fibre optic probes were used, without the addition of expensive optical filters. Good quality in vivo Raman spectra were successfully obtained with a 1 s integration time in the high frequency (HF) range from normal tissue and polyps of patients during a colonoscopy. The polyps were subsequently removed, and their pathology determined. The acquired in vivo Raman spectra showed clear changes between tissue with normal and tubular adenoma pathology. Further clinical study with this low cost HF Raman probe is warranted to fully test its clinical utility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. High-pressure investigation of CaTiO3 up to 60 GPa using x-ray diffraction and Raman spectroscopy

    Science.gov (United States)

    Guennou, Mael; Bouvier, Pierre; Krikler, Benjamin; Kreisel, Jens; Haumont, Raphaël; Garbarino, Gaston

    2010-10-01

    In this work, we investigate calcium titanate [CaTiO3(CTO)] using x-ray diffraction and Raman spectroscopy up to 60 GPa and 55 GPa, respectively. Both experiments show that the orthorhombic Pnma structure remains stable up to the highest pressures measured, in contradiction to ab initio predictions. A fit of the compression data with a second-order Birch-Murnaghan equation of state yields a bulk modulus K0 of 181.0(6) GPa. The orthorhombic distortion is found to increase slightly with pressure, in agreement with previous experiments at lower pressures and the general rules for the evolution of perovskites under pressure. High-pressure polarized Raman spectra also enable us to clarify the Raman mode assignment of CTO and identify the modes corresponding to rigid rotation of the octahedra, A -cation shifts, and Ti-O bond stretching. The Raman signature is then discussed in terms of compression mechanisms.

  7. High-pressure X-ray diffraction and Raman scattering of LiTaO sub 3

    CERN Document Server

    Zhang Wei; Pan Yue Wu; Dong Shu Shan; Zou Guang Tian; Liu Jing

    2002-01-01

    The authors study the energy-dispersive x-ray diffraction and Raman scattering of LiTaO sub 3 at high pressure. The result remains stable up to 36 GPa. The average isothermal bulk modulus and its pressure derivative are obtained to be k sub 0 =(225 +- 6) GPa and k sub 0 '=1.3 +- 0.5 at zero pressure by the Birch-Murnaghan equation of state and the 'universal' equation of state. The linear incompressibility of LiTaO sub 3 between the a- and c-directions differs by a factor of four, which shows that the compression is anisotropic

  8. High Speed Signal Wavelength Conversion Using Stimulated Raman Effect in Ultrasmall Silicon-on-Insulator Optical Waveguides

    Institute of Scientific and Technical Information of China (English)

    WU Jian-Wei; LUO Feng-Guang; GALLEP Cristiano de Mello

    2008-01-01

    We propose the high speed signal wavelength conversion based on stimulated Raman effect on silicon waveguides.Simulation results of non-return-to-zero(NRZ)pseudorandom bit sequence(27-1 code)at 500-Gb/s rate of conversion in an ultrasmall silicon-on-insulator(SOI)optical wavegnide are presented by co-propagating pump optical field.The most attractive issue is that the inverted converted signal can be obtained at the same wavelength as that of primary signal.In addition,the conversion performances,including extinction ratio(ER)and average peak power of conversion signal,depend strongly on the launching pump intensity.

  9. High-temperature Raman study of L-alanine, L-threonine and taurine crystals related to thermal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Cavaignac, A.L.O. [Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410 (Brazil); Lima, R.J.C., E-mail: ricardo.lima.ufma@gmail.com [Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410 (Brazil); Façanha Filho, P.F. [Centro de Ciências Sociais, Saúde e Tecnologia, Universidade Federal do Maranhão, Imperatriz, MA 65900-410 (Brazil); Moreno, A.J.D. [Coordenação de Ciências Naturais, Universidade Federal do Maranhão, Bacabal, MA 65700-000 (Brazil); Freire, P.T.C. [Departamento de Física, Universidade Federal do Ceará, Fortaleza, CE 60455-760 (Brazil)

    2016-03-01

    In this work high-temperature Raman spectra are used to compare temperature dependence of the lattice mode wavenumber of L-alanine, L-threonine and taurine crystals. Anharmonic effects observed are associated with intermolecular N-H· · ·O hydrogen bond that plays an important role in thermal decomposition process of these materials. Short and strong hydrogen bonds in L-alanine crystal were associated with anharmonic effects in lattice modes leading to low thermal stability compared to taurine crystals. Connection between thermal decomposition process and anharmonic effects is furnished for the first time.

  10. High capacity and high rate capability of nanostructured CuFeO 2 anode materials for lithium-ion batteries

    Science.gov (United States)

    Lu, Lin; Wang, Jia-Zhao; Zhu, Xue-Bin; Gao, Xuan-Wen; Liu, Hua-Kun

    Non-toxic, cheap, nanostructured ternary transition metal oxide CuFeO 2 was synthesised using a simple sol-gel method at different temperatures. The effects of the processing temperature on the particle size and electrochemical performance of the nanostructured CuFeO 2 were investigated. The electrochemical results show that the sample synthesised at 650 °C shows the best cycling performance, retaining a specific capacity of 475 mAh g -1 beyond 100 cycles, with a capacity fading of less than 0.33% per cycle. The electrode also exhibits good rate capability in the range of 0.5 C-4 C. At the high rate of 4 C, the reversible capacity of CuFeO 2 is around 170 mAh g -1. It is believed that the ternary transition metal oxide CuFeO 2 is quite acceptable compared with other high performance nanostructured anode materials.

  11. Direct molecule-specific glucose detection by Raman spectroscopy based on photonic crystal fiber.

    Science.gov (United States)

    Yang, Xuan; Zhang, Alissa Y; Wheeler, Damon A; Bond, Tiziana C; Gu, Claire; Li, Yat

    2012-01-01

    This paper reports the first step toward the development of a glucose biosensor based on Raman spectroscopy and a photonic crystal fiber (PCF) probe. Historically, it has been very challenging to detect glucose directly by Raman spectroscopy due to its inherently small Raman scattering cross-section. In this work, we report the first quantitative glucose Raman detection in the physiological concentration range (0-25 mM) with a low laser power (2 mW), a short integration time (30 s), and an extremely small sampling volume (~50 nL) using the highly sensitive liquid-filled PCF probe. As a proof of concept, we also demonstrate the molecular specificity of this technique in the presence of a competing sugar, such as fructose. High sensitivity, flexibility, reproducibility, low cost, small sampling volume, and in situ remote sensing capability make PCF a very powerful platform for potential glucose detection based on Raman spectroscopy.

  12. A pseudo-Voigt component model for high-resolution recovery of constituent spectra in Raman spectroscopy

    DEFF Research Database (Denmark)

    Alstrøm, Tommy Sonne; Schmidt, Mikkel Nørgaard; Rindzevicius, Tomas

    2017-01-01

    Raman spectroscopy is a well-known analytical technique for identifying and analyzing chemical species. Since Raman scattering is a weak effect, surface-enhanced Raman spectroscopy (SERS) is often employed to amplify the signal. SERS signal surface mapping is a common method for detecting trace...

  13. On the Raman Detectability of Biomarkers in Geological Matrices in preparation for Mars Exploration

    Science.gov (United States)

    Malherbe, Cedric; Hutchinson, Ian B.; DEMARET, Lucas; INGLEY, Richard; EDWARDS, Howell G. M.; EPPE, Gauthier; ExoMars Raman Team at the University of Leicester, Group of Inorganic Analytical Chemsitry at the University of Liege

    2016-10-01

    In 2020, Raman spectrometers will be launched to Mars as part of the ESA/ROSCOSMOS's ExoMars 2020 mission and the NASA's Mars 2020 mission. The miniaturized Raman instrument on board the ExoMars rover has two scientific goals: characterize the geochemistry of the surface and subsurface of Mars, and search for molecular evidence of past and present life. Raman spectrometers have indeed the capability to characterize non-destructively the geology of the rocky surface of Mars. Information on the nature and the molecular composition of the surface and subsurface of Mars will provide valuable information about the habitability of the red planet. In addition, Raman spectrometers have the ability to detect potential molecular biomarkers which are substances obtained by biochemical processes or their derivatives preserved in a protective geological niche. In preparation for Mars mission, studying the detection capability of miniaturized Raman spectrometers (specifically developed for space missions and therefore compromised by the associated challenging constraints) is highly important, on both lab synthetic samples and natural terrestrial analogues samples. We present here an analytical strategy to determine the limit of detection achievable based on Raman spectral images. Raman data were recorded with benchtop instruments and a Raman Laser Spectrometer prototype developed at the University of Leicester to optimize/characterize the camera system that will be used for the ExoMars mission.

  14. Ionosphere data assimilation capabilities for representing the high-latitude geomagnetic storm event in September 2011

    Science.gov (United States)

    Solomentsev, Dmitry; Jacobsen, Knut Stanley; Khattatov, Boris; Khattatov, Vyacheslav; Cherniak, Yakov; Titov, Anton

    2014-12-01

    Severe geomagnetic storms have a strong impact on space communication and satellite navigation systems. Forecasting the appearance of geomagnetically induced disturbances in the ionosphere is one of the urgent goals of the space weather community. The challenge is that the processes governing the distribution of the crucial ionospheric parameters have a rather poor quantitative description, and the models, built using the empirical parameterizations, have limited capabilities for operational purposes. On the other hand, data assimilation techniques are becoming more and more popular for nowcasting the state of the large-scale geophysical systems. We present an example of an ionospheric data assimilation system performance assessment during a strong geomagnetic event, which took place on 26 September 2011. The first-principle model has assimilated slant total electron content measurements from a dense network of ground stations, provided by the Norwegian Mapping Authority. The results have shown satisfactory agreement with independent data and demonstrate that the assimilation model is accurate to about 2-4 total electron content units and can be used for operational purposes in high-latitude regions. The operational system performance assessment is the subject of future work.

  15. A Microfabricated 96-Well 3D Assay Enabling High-Throughput Quantification of Cellular Invasion Capabilities

    Science.gov (United States)

    Hao, Rui; Wei, Yuanchen; Li, Chaobo; Chen, Feng; Chen, Deyong; Zhao, Xiaoting; Luan, Shaoliang; Fan, Beiyuan; Guo, Wei; Wang, Junbo; Chen, Jian

    2017-01-01

    This paper presents a 96-well microfabricated assay to study three-dimensional (3D) invasion of tumor cells. A 3D cluster of tumor cells was first generated within each well by seeding cells onto a micro-patterned surface consisting of a central fibronectin-coated area that promotes cellular attachment, surrounded by a poly ethylene glycol (PEG) coated area that is resistant to cellular attachment. Following the formation of the 3D cell clusters, a 3D collagen extracellular matrix was formed in each well by thermal-triggered gelation. Invasion of the tumor cells into the extracellular matrix was subsequently initiated and monitored. Two modes of cellular infiltration were observed: A549 cells invaded into the extracellular matrix following the surfaces previously coated with PEG molecules in a pseudo-2D manner, while H1299 cells invaded into the extracellular matrix in a truly 3D manner including multiple directions. Based on the processing of 2D microscopic images, a key parameter, namely, equivalent invasion distance (the area of invaded cells divided by the circumference of the initial cell cluster) was obtained to quantify migration capabilities of these two cell types. These results validate the feasibility of the proposed platform, which may function as a high-throughput 3D cellular invasion assay. PMID:28240272

  16. Preparation of graphene oxide-silver nanoparticle nanohybrids with highly antibacterial capability.

    Science.gov (United States)

    Zhu, Zhijun; Su, Min; Ma, Lan; Ma, Lina; Liu, Dianjun; Wang, Zhenxin

    2013-12-15

    A simple method based on electrostatic interactions was utilized to assemble silver nanoparticles (AgNPs) to graphene oxide (GO) sheets. This method allows conjugation of AgNPs with desired morphologies (densities, sizes and shapes) onto GO. In this process, poly(diallyldimethylammonium chloride) (PDDA) was introduced as an adhesive agent. The as-prepared graphene oxide-AgNPs composites (GO-AgNPs) have enhanced colloid stability and photo-stability than that of AgNPs. After conjugating to GO sheets, the antibacterial activities of AgNPs against Gram negative (G-) bacterial strain (Escherichia coli, E. coli) and Gram positive (G+) bacterial strain (Bacillus subtilis, B. subtilis) have been improved significantly. The antibacterial activity of GO-AgNPs is dependent on the size of AgNPs, i.e. the small AgNPs modified GO sheets show more effective antibacterial capability than that of large AgNPs modified GO sheets. Compared with AgNPs, the enhanced antibacterial activity of GO-AgNPs might not only be due to high stability of AgNPs anchored on GO sheets, but also the positive charged surface of hybrids which increases the electrostatic interaction of bacterial cell membrane with nanohybrids.

  17. High-temperature X-ray diffraction and Raman spectroscopy of diopside and pseudowollastonite

    Science.gov (United States)

    Richet, Pascal; Mysen, Bjorn O.; Ingrin, Jannick

    Diopside (CaMgSi2O6) and pseudowollastonite (CaSiO3) have been studied by X-ray powder diffraction and Raman spectroscopy up to their respective melting points. In agreement with previous unit-cell parameters determinations below 1100 K, thermal expansion of diopside along the a and c axis is much smaller than along the b axis. For pseudowollastonite, the axis expansivity increases slightly in the order b>a>c. For both minerals, the change in unit-cell angles is very small and there are no anomalous variations of the other unit-cell parameters near the melting point. With increasing temperatures, the main changes observed in the Raman spectra are strong increases of the linewidths for those bands which mainly represent Si-O-Si bending (near 600 cm-1) or involve Ca-O or Mg-O stretching, in the range 270-500 cm-1 for diopside, and 240-450 cm-1 for pseudowollastonite. At temperatures near the onset of calorimetric premelting effects, this extensive band widening results in a broad Raman feature that can no longer be deconvoluted into its individual components. No significant changes affect the Si-O streching modes. For both diopside and pseudowollastonite, premelting appears to be associated with enhanced dynamics of the alkaline-earth elements. This conclusion contrasts markedly with that drawn for sodium metasilicate in which weaker bonding of sodium allows the silicate framework to distort and deform in such a way as to prefigure the silicate entities present in the melt.

  18. Raman spectral analysis of high efficiency PVDF: nanocomposite films doped with MWCNT

    Science.gov (United States)

    Guggilla, Padmaja; Kassu, Aschalew; Powell, Rachel

    2016-09-01

    Nanocomposite films are of great interest in the development of infrared detectors and other technology. Polyvinylidenefluoride (PVDF) with excellent pyroelectric and piezoelectric properties such as fast, dynamic response has great potential for use in touch/tactile sensors, infrared detectors and thermal vidicon/imaging devices. PVDF:LiNbO3, PVDF:LiTaO3, and PVDF:BaTiO3 nanocomposites are fabricated with optimal characteristics using the solution casting technique. All these nanocomposite films are doped with multi-walled carbon nanotubes (MWCNT) with various weight percentages. The objective of this research was to characterize the low-frequency dielectric constant, dielectric loss and the pyroelectric properties of these composite films and thus the materials figures of merit for their use in space applications. Nanocomposites are also characterized using Raman Spectroscopy to get the finger print of these materials and their existence in the composite film. Dielectric constant and dielectric loss results are presented as a function of temperature and frequency, and pyroelectric coefficient as a function of temperature. Raman Spectrum of the nanocomposite materials is presented using 785nm laser. Obtained Raman spectrum matches with the literature available. Authors also observed that both microscopic structure and environmental conditions contributed to observed properties. Dielectric loss resulted from electromagnetic energy loss as manifested through phase differences between low-frequency input signal to the films and time varying polarization. In addition, both the dielectric constant and dielectric loss were observed to be highest for MWCNT doped nanocomposite materials compared to pure PVDF and pure PVDF:LiNbO3, PVDF:LiTaO3, and PVDF:BaTiO3. Among all the MWCNT doped nanocomposite materials PVDF:LiTaO3 showed the highest Pyroelectric coefficient which would make the best material to be used in space applications compared to the other materials at test.

  19. Composition and (in)homogeneity of carotenoid crystals in carrot cells revealed by high resolution Raman imaging

    Science.gov (United States)

    Roman, Maciej; Marzec, Katarzyna M.; Grzebelus, Ewa; Simon, Philipp W.; Baranska, Malgorzata; Baranski, Rafal

    2015-02-01

    Three categories of roots differing in both β/α-carotene ratio and in total carotenoid content were selected based on HPLC measurements: high α- and β-carotene (HαHβ), low α- and high β-carotene (LαHβ), and low α- and low β-carotene (LαLβ). Single carotenoid crystals present in the root cells were directly measured using high resolution Raman imaging technique with 532 nm and 488 nm lasers without compound extraction. Crystals of the HαHβ root had complex composition and consisted of β-carotene accompanied by α-carotene. In the LαHβ and LαLβ roots, measurements using 532 nm laser indicated the presence of β-carotene only, but measurements using 488 nm laser confirmed co-occurrence of xanthophylls, presumably lutein. Thus the results show that independently on carotenoid composition in the root, carotenoid crystals are composed of more than one compound. Individual spectra extracted from Raman maps every 0.2-1.0 μm had similar shapes in the 1500-1550 cm-1 region indicating that different carotenoid molecules were homogeneously distributed in the whole crystal volume. Additionally, amorphous carotenoids were identified and determined as composed of β-carotene molecules but they had a shifted the ν1 band probably due to the effect of bonding of other plant constituents like proteins or lipids.

  20. Assessment of the Protein-Protein Interactions in a Highly Concentrated Antibody Solution by Using Raman Spectroscopy.

    Science.gov (United States)

    Ota, Chikashi; Noguchi, Shintaro; Nagatoishi, Satoru; Tsumoto, Kouhei

    2016-04-01

    To investigate the protein-protein interactions of a highly concentrated antibody solution that could cause oligomerization or aggregation and to develop a better understanding of the optimization of drug formulations. In this study, we used Raman spectroscopy to investigate the structure and interactions of a highly concentrated antibody solution over a wide range of concentrations (10-200 mg/mL) with the aid of a multivariate analysis. Our analysis of the amide I band, I 856 /I 830 of Tyr, and the relative intensity at 1004 cm(-1) of the Phe and OH stretching region at around 3000 cm(-1) showed that across this wide range of concentrations, the secondary structure of the IgG molecules did not change; however, short-range attractive interactions around the Tyr and Phe residues occurred as the distance between the IgG molecules decreased with increasing concentration. Analysis of the OH stretching region at around 3000 cm(-1) showed that these short-range attractive interactions correlated with the amount of hydrated water around the IgG molecules. Our data show that Raman spectroscopy can provide valuable information of the protein-protein interactions based on conformational approaches to support conventional colloidal approaches, especially for analyses of highly concentrated solutions.

  1. Raman backscatter as a remote laser power sensor in high-energy-density plasmas

    CERN Document Server

    Moody, J D; Divol, L; Michel, P; Robey, H F; LePape, S; Ralph, J; Ross, J S; Glenzer, S H; Kirkwood, R K; Landen, O L; MacGowan, B J; Nikroo, A; Williams, E A

    2013-01-01

    Stimulated Raman backscatter (SRS) is used as a remote sensor to quantify the instantaneous laser power after transfer from outer to inner cones that cross in a National Ignition Facility (NIF) gas-filled hohlraum plasma. By matching SRS between a shot reducing outer vs a shot reducing inner power we infer that ~half of the incident outer-cone power is transferred to inner cones, for the specific time and wavelength configuration studied. This is the first instantaneous non-disruptive measure of power transfer in an indirect drive NIF experiment using optical measurements.

  2. Timing capabilities of garnet crystals for detection of high energy charged particles

    Science.gov (United States)

    Lucchini, M. T.; Gundacker, S.; Lecoq, P.; Benaglia, A.; Nikl, M.; Kamada, K.; Yoshikawa, A.; Auffray, E.

    2017-04-01

    Particle detectors at future collider experiments will operate at high collision rates and thus will have to face high pile up and a harsh radiation environment. Precision timing capabilities can help in the reconstruction of physics events by mitigating pile up effects. In this context, radiation tolerant, scintillating crystals coupled to silicon photomultipliers (SiPMs) can provide a flexible and compact option for the implementation of a precision timing layer inside large particle detectors. In this paper, we compare the timing performance of aluminum garnet crystals (YAG: Ce, LuAG: Ce, GAGG: Ce) and the improvements of their time resolution by means of codoping with Mg2+ ions. The crystals were read out using SiPMs from Hamamatsu glued to the rear end of the scintillator and their timing performance was evaluated by measuring the coincidence time resolution (CTR) of 150 GeV charged pions traversing a pair of crystals. The influence of crystal properties, such as density, light yield and decay kinetics on the timing performance is discussed. The best single detector time resolutions are in the range of 23-30 ps (sigma) and only achieved by codoping the garnet crystals with divalent ions, such as Mg2+. The much faster scintillation decay in the co-doped samples as compared to non co-doped garnets explains the higher timing performance. Samples of LSO: Ce, Ca and LYSO:Ce crystals have also been used as reference time device and showed a time resolution at the level of 17 ps, in agreement with previous results.

  3. Multi-Mission Capable, High g Load mW RPS

    Energy Technology Data Exchange (ETDEWEB)

    John C. Bass; Nathan Hiller; Velimir Jovanovic; Norbert B. Elsner

    2007-05-23

    Over the past few years Hi-Z has been developing a wide range of mW generators and life testing thermoelectric modules for the Department of Energy (DOE) to fulfill requirements by NASA Ames and other agencies. The purpose of this report is to determine the capabilities of a wide range of mW generators for various missions. In the 1st quarterly report the power output of various mW generators was determined via thermal and mechanical modeling. The variable attributes of each generator modeled were: the number of RHUs (1-8), generator outer diameter (1.25-4 in.), and G-load (10, 500, or 2,000). The resultant power output was as high as 180 mW for the largest generator with the lowest Gload. Specifically, we looked at the design of a generator for high G loading that is insulated with Xenon gas and multifoil solid insulation. Because the design of this new generator varied considerably from the previous generator design, it was necessary to show in detail how it is to be assembled, calculate them as of the generator and determine the heat loss from the system. A new method of assembling the RHU was also included as part of the design. As a side issue we redesigned the test stations to provide better control of the cold sink temperature. This will help in reducing the test data by eliminating the need to 'normalize' the data to a specific temperature. In addition these new stations can be used to simulate the low ambient temperatures associated with Mars and other planets.

  4. Environmentally Responsive Surface-Enhanced Raman Scattering Substrates for High Sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Hongdeok; Jung, Chan Woo; Jalani, Ghulam; Lim, Dong Woo [Hanyang Univ., Ansan (Korea, Republic of)

    2013-11-15

    We first report the synthesis and characterization of a new class of thermoresponsive SERS substrates composed of branched GNPs (bGNPs) with sharp features and poly(NIPAM-co-allylamonium chloride) (p(NIPAM-co-AA)) chemically conjugated with 1,10-decanedithiol of the self-assembled monolayer (SAM) of the gold-patterned microarray chip (Figure 1). As organic-inorganic composites, these SERS substrates were formed by strong ionic interaction between negatively charged bGNPs and positively charged p(NIPAM-co-AA) tethered on the gold pattern. When rhodamine B isothiocyanate (RBITC) was introduced to bGNPs as Raman dye, thermally-triggered collapse and aggregation of p(NIPAM-co-AA) chains in aqueous solution above the lower critical solution temperature (LCST) produced a SERS signal higher than that seen below LCST, potentially due to the decreased distance between bGNPs or between bGNPs and the gold pattern. Surface-enhanced Raman scattering (SERS) has been of growing interest as a powerful tool to study vibrational information of molecules adsorbed on metallic nanoparticles (MNPs)

  5. High-Resolution Distance Dependence Study of Surface-Enhanced Raman Scattering Enabled by Atomic Layer Deposition.

    Science.gov (United States)

    Masango, Sicelo S; Hackler, Ryan A; Large, Nicolas; Henry, Anne-Isabelle; McAnally, Michael O; Schatz, George C; Stair, Peter C; Van Duyne, Richard P

    2016-07-13

    We present a high-resolution distance dependence study of surface-enhanced Raman scattering (SERS) enabled by atomic layer deposition (ALD) at 55 and 100 °C. ALD is used to deposit monolayers of Al2O3 on bare silver film over nanospheres (AgFONs) and AgFONs functionalized with self-assembled monolayers. Operando SERS is used to measure the intensities of the Al-CH3 and C-H stretches from trimethylaluminum (TMA) as a function of distance from the AgFON surface. This study clearly demonstrates that SERS on AgFON substrates displays both a short- and long-range nanometer scale distance dependence. Excellent agreement is obtained between these experiments and theory that incorporates both short-range and long-range terms. This is a high-resolution operando SERS distance dependence study performed in one integrated experiment using ALD Al2O3 as the spacer layer and Raman label simultaneously. The long-range SERS distance dependence should make it possible to detect chemisorbed surface species located as far as ∼3 nm from the AgFON substrate and will provide new insight into the surface chemistry of ALD and catalytic reactions.

  6. The use of segmented cathode of a drift tube for designing a track detector with a high rate capability

    CERN Document Server

    Kuchinskiy, N A; Duginov, V N; Zyazyulya, F E; Korenchenko, A S; Kolesnikov, A O; Kravchuk, N P; Movchan, S A; Rudenko, A I; Smirnov, V S; Khomutov, N V; Chekhovsky, V A

    2013-01-01

    Detector rate capability is one of the main parameters for designing a new detector for high energy physics due to permanent rise of the beam luminosity of modern accelerators. One of the widely used detectors for particle track reconstruction is a straw detector based on drift tubes. The rate capability of such detectors is limited by the parameters of readout electronics. The traditional method of increasing detector rate capability is increasing their granularity (a number of readout channels) by reducing the straw diameter and/or by dividing the straw anode wire into two parts (for decreasing the rate per readout channel). A new method of designing straw detectors with a high rate capability is presented and tested. The method is based on dividing the straw cathode into parts and independent readout of each part.

  7. MAINTAINING HIGH RESOLUTION MASS SPECTROMETRY CAPABILITIES FOR NATIONAL NUCLEAR SECURITY ADMINISTRATION APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Wyrick, S.; Cordaro, J.; Reeves, G.; Mcintosh, J.; Mauldin, C.; Tietze, K.; Varble, D.

    2011-06-06

    The Department of Energy (DOE) National Nuclear Security Administration (NNSA) has a specialized need for analyzing low mass gas species at very high resolutions. The currently preferred analytical method is electromagnetic sector mass spectrometry. This method allows the NNSA Nuclear Security Enterprise (NSE) to resolve species of similar masses down to acceptable minimum detection limits (MDLs). Some examples of these similar masses are helium-4/deuterium and carbon monoxide/nitrogen. Through the 1980s and 1990s, there were two vendors who supplied and supported these instruments. However, with declining procurements and down turns in the economy, the supply of instruments, service and spare parts from these vendors has become less available, and in some cases, nonexistent. The largest NSE user of this capability is the Savannah River Site (SRS), located near Aiken, South Carolina. The Research and Development Engineering (R&DE) Group in the Savannah River National Laboratory (SRNL) investigated the areas of instrument support that were needed to extend the life cycle of these aging instruments. Their conclusions, as to the focus areas of electromagnetic sector mass spectrometers to address, in order of priority, were electronics, software and hardware. Over the past 3-5 years, the R&DE Group has designed state of the art electronics and software that will allow high resolution legacy mass spectrometers, critical to the NNSA mission, to be operated for the foreseeable future. The funding support for this effort has been from several sources, including the SRS Defense Programs, NNSA Readiness Campaign, Pantex Plant and Sandia National Laboratory. To date, electronics systems have been upgraded on one development system at SRNL, two production systems at Pantex and one production system at Sandia National Laboratory. An NSE working group meets periodically to review strategies going forward. The R&DE Group has also applied their work to the electronics for a

  8. Random Raman lasing

    CERN Document Server

    Hokr, Brett H; Mason, John D; Beier, Hope T; Rockwll, Benjamin A; Thomas, Robert J; Noojin, Gary D; Petrov, Georgi I; Golovan, Leonid A; Yakovlev, Vladislav V

    2013-01-01

    Propagation of light in a highly scattering medium is among the most fascinating optical effect that everyone experiences on an everyday basis and possesses a number of fundamental problems which have yet to be solved. Conventional wisdom suggests that non-linear effects do not play a significant role because the diffusive nature of scattering acts to spread the intensity, dramatically weakening these effects. We demonstrate the first experimental evidence of lasing on a Raman transition in a bulk three-dimensional random media. From a practical standpoint, Raman transitions allow for spectroscopic analysis of the chemical makeup of the sample. A random Raman laser could serve as a bright Raman source allowing for remote, chemically specific, identification of powders and aerosols. Fundamentally, the first demonstration of this new light source opens up an entire new field of study into non-linear light propagation in turbid media, with the most notable application related to non-invasive biomedical imaging.

  9. Optical Stark effect in the four-wave mixing and stimulated Raman spectra of N2

    Science.gov (United States)

    Moosmuller, H.; She, C. Y.; Huo, Winifred M.

    1989-01-01

    The influence of the optical Stark effect on spectral line shapes in four-wave-mixing Raman spectroscopy (FWMRS) and stimulated Raman spectroscopy (SRS) is investigated experimentally and theoretically. Using an experimental setup capable of rapid alternation between the simultaneous measurement of coherent Stokes Raman spectroscopy and inverse Raman spectroscopy at low and high intensities, together with a sophisticated frequency reference scheme, it was possible to perform a rather direct comparison between Stark-broadened and non-Stark-broadened spectra of both classes of Raman spectroscopies. The results demonstrate that SRS spectra show more Stark shift and broadening than their FWMRS counterparts. A discrepancy with theoretical results is pointed out, and an attempt is made to explain it.

  10. Anthropometric Characteristics and Performance Capabilities of Highly Trained Motocross Athletes Compared With Physically Active Men.

    Science.gov (United States)

    Bach, Christopher W; Brown, Ann F; Kinsey, Amber W; Ormsbee, Michael J

    2015-12-01

    Motocross (MX) is a physically demanding sport with little research concerning the physiological characteristics of these athletes. The purpose of this study was to assess the anthropometric characteristics and performance capabilities of highly trained MX athletes (n = 20; 19 ± 1.6 years) compared with age-matched physically active (PA) men (n = 22; 22 ± 2.9 years). Testing was performed on 2 occasions. The initial visit consisted of a personality assessment in addition to the following (in order): anthropometrics, body composition, anaerobic power/fatigue, isokinetic/isometric strength and fatigue, and flexibility. The second visit consisted of peak oxygen uptake (V[Combining Dot Above]O2peak), handgrip strength, maximum push-ups in 1 minute, extended arm hang time to exhaustion (TTE), and 90° weighted wall-sit tests. All anthropometric and performance data were analyzed using independent samples t-tests to compare group means. Significance was set at p ≤ 0.05. Data are reported as mean ± SD. There were no significant differences between groups in anthropometric or body composition measurements except android fat (MX: 11.7 ± 1.9% vs. PA: 16.4 ± 8.4%, p = 0.04) and biceps circumference (MX: 30.1 ± 2.0 vs. PA: 33.1 ± 3.2 cm, p = 0.001). MX had significantly higher absolute and relative mean anaerobic power (747.3 ± 63.7 vs. 679.7 ± 93.5 W, p = 0.009 and 10.0 ± 0.6 vs. 9.2 ± 1.3 W·kg, p = 0.002, respectively), relative anaerobic peak power (12.7 ± 0.8 vs. 11.9 ± 1.4 W·kg, p = 0.029), TTE (550.1 ± 70.6 vs. 470.1 ± 93.2 seconds, p = 0.004), and extended arm hang duration (113.3 ± 44.9 vs. 73.4 ± 25.3 seconds, p = 0.001). These results suggest highly trained MX athletes possess certain physiological adaptations that likely result from sport-specific demands compared with PA.

  11. Effect of shear stress on the high-pressure behaviour of nitromethane: Raman spectroscopy in a shear diamond anvil cell

    Science.gov (United States)

    Hebert, Philippe; Isambert, Aude; Petitet, Jean-Pierre; Zerr, Andreas

    2009-06-01

    A detailed description of the reaction mechanisms occurring in shock-induced decomposition of condensed energetic materials is very important for a comprehensive understanding of detonation. Besides pressure and temperature effects, shear stress has also been proposed to play an important role in the initiation and decomposition mechanisms. In order to study this effect, a Shear Diamond Anvil Cell (SDAC) has been developed. It is actually a classical DAC with the upper diamond anvil rotating about the compression axis relative to the opposite anvil. In this paper, we present a Raman spectroscopy study of the effect of shear stress on the high-pressure behaviour of nitromethane. Two major effects of shear stress are observed in our experiments. The first one is a lowering of the pressures at which the different structural modifications that nitromethane undergoes are observed. The second effect is observed at 28 GPa where sudden decomposition of the sample occurs just after shear application. Observation of the sample after decomposition shows the presence of a black residue which is composed of carbon as indicated by the Raman spectrum. [1] Manaa, M. R., Fried, L. E., and Reed, E. J., Journal of Computer-Aided Materials Design, 10, pp 75-97, 2003.

  12. High wavenumber Raman spectroscopy in the characterization of urinary metabolites of normal subjects, oral premalignant and malignant patients

    Science.gov (United States)

    Brindha, Elumalai; Rajasekaran, Ramu; Aruna, Prakasarao; Koteeswaran, Dornadula; Ganesan, Singaravelu

    2017-01-01

    Urine has emerged as one of the diagnostically potential bio fluids, as it has many metabolites. As the concentration and the physiochemical properties of the urinary metabolites may vary under pathological transformation, Raman spectroscopic characterization of urine has been exploited as a significant tool in identifying several diseased conditions, including cancers. In the present study, an attempt was made to study the high wavenumber (HWVN) Raman spectroscopic characterization of urine samples of normal subjects, oral premalignant and malignant patients. It is concluded that the urinary metabolites flavoproteins, tryptophan and phenylalanine are responsible for the observed spectral variations between the normal and abnormal groups. Principal component analysis-based linear discriminant analysis was carried out to verify the diagnostic potentiality of the present technique. The discriminant analysis performed across normal and oral premalignant subjects classifies 95.6% of the original and 94.9% of the cross-validated grouped cases correctly. In the second analysis performed across normal and oral malignant groups, the accuracy of the original and cross-validated grouped cases was 96.4% and 92.1% respectively. Similarly, the third analysis performed across three groups, normal, oral premalignant and malignant groups, classifies 93.3% and 91.2% of the original and cross-validated grouped cases correctly.

  13. High Pressure Raman Spectroscopy Of TiO2 Thin Films

    Science.gov (United States)

    Hess, Nancy J.; Exarhos, Gregory J.

    1989-07-01

    The pressure dependences of the Raman active modes in submicrometer films of the anatase and rutile crystalline phases of TiO2 have been determined at pressures approaching 90 Kbar. Films investigated have been prepared by reactive sputter deposition and sol-gel techniques. Band frequency shifts as a function of applied pressure for the rutile phase are in agreement with measurements from single crystal samples. However, sol-gel films (anatase) exhibit larger frequency shifts than powder or single crystal samples, and do not undergo the expected pressure-induced phase transformation to the Ti02-II phase. This anomalous pressure response is discussed in terms of the complex film microstructure evaluated from TEM cross-sectional measurements.

  14. Highly-Sensitive Surface-Enhanced Raman Spectroscopy (SERS)-based Chemical Sensor using 3D Graphene Foam Decorated with Silver Nanoparticles as SERS substrate

    Science.gov (United States)

    Srichan, Chavis; Ekpanyapong, Mongkol; Horprathum, Mati; Eiamchai, Pitak; Nuntawong, Noppadon; Phokharatkul, Ditsayut; Danvirutai, Pobporn; Bohez, Erik; Wisitsoraat, Anurat; Tuantranont, Adisorn

    2016-03-01

    In this work, a novel platform for surface-enhanced Raman spectroscopy (SERS)-based chemical sensors utilizing three-dimensional microporous graphene foam (GF) decorated with silver nanoparticles (AgNPs) is developed and applied for methylene blue (MB) detection. The results demonstrate that silver nanoparticles significantly enhance cascaded amplification of SERS effect on multilayer graphene foam (GF). The enhancement factor of AgNPs/GF sensor is found to be four orders of magnitude larger than that of AgNPs/Si substrate. In addition, the sensitivity of the sensor could be tuned by controlling the size of silver nanoparticles. The highest SERS enhancement factor of ∼5 × 104 is achieved at the optimal nanoparticle size of 50 nm. Moreover, the sensor is capable of detecting MB over broad concentration ranges from 1 nM to 100 μM. Therefore, AgNPs/GF is a highly promising SERS substrate for detection of chemical substances with ultra-low concentrations.

  15. Discriminant Analysis of Raman Spectra for Body Fluid Identification for Forensic Purposes

    Directory of Open Access Journals (Sweden)

    Vitali Sikirzhytski

    2010-03-01

    Full Text Available Detection and identification of blood, semen and saliva stains, the most common body fluids encountered at a crime scene, are very important aspects of forensic science today. This study targets the development of a nondestructive, confirmatory method for body fluid identification based on Raman spectroscopy coupled with advanced statistical analysis. Dry traces of blood, semen and saliva obtained from multiple donors were probed using a confocal Raman microscope with a 785-nm excitation wavelength under controlled laboratory conditions. Results demonstrated the capability of Raman spectroscopy to identify an unknown substance to be semen, blood or saliva with high confidence.

  16. Nano-sized structured layered positive electrode materials to enable high energy density and high rate capability lithium batteries

    Science.gov (United States)

    Deng, Haixia; Belharouak, Ilias; Amine, Khalil

    2012-10-02

    Nano-sized structured dense and spherical layered positive active materials provide high energy density and high rate capability electrodes in lithium-ion batteries. Such materials are spherical second particles made from agglomerated primary particles that are Li.sub.1+.alpha.(Ni.sub.xCo.sub.yMn.sub.z).sub.1-tM.sub.tO.sub.2-dR.sub.d- , where M is selected from can be Al, Mg, Fe, Cu, Zn, Cr, Ag, Ca, Na, K, In, Ga, Ge, V, Mo, Nb, Si, Ti, Zr, or a mixture of any two or more thereof, R is selected from F, Cl, Br, I, H, S, N, or a mixture of any two or more thereof, and 0.ltoreq..alpha..ltoreq.0.50; 0

  17. Highly efficient cascaded P-doped Raman fiber laser pumped by Nd:YVO4 solid-state laser

    Institute of Scientific and Technical Information of China (English)

    Chaohong Huang; Zhiping Cai; Zhengqian Luo; Wencai Huang; Huiying Xu; Chenchun Ye

    2008-01-01

    A highly efficient cascaded P-doped Raman fiber laser (RFL) pumped by a 1064-nm continuous wave (CW) Nd:YVO4 solid-state laser is reported. 1.15-W CW output power at 1484 nm is obtained while the input pump power is 4 W, corresponding to the power conversion efficiency of 28.8%. The threshold pump power for the second-order Stokes radiation is 1.13 W. The slope efficiency is as high as 42.6%. The experimental results are in good agreement with theoretical ones. Furthermore, the power instability of the P-doped RFL at 1484 nm in an hour is observed to be less than 5%.

  18. Process Capability of High Speed Micro End-Milling of Inconel 718 with Minimum Quantity Lubrication

    Science.gov (United States)

    Rahman, Mohamed Abd; Yeakub Ali, Mohammad; Rahman Shah Rosli, Abdul; Banu, Asfana

    2017-03-01

    The demand for micro-parts is expected to grow and micro-machining has been shown to be a viable manufacturing process to produce these products. These micro-products may be produced from hard-to-machine materials such as superalloys under little or no metal cutting fluids to reduce machining cost or drawbacks associated with health and environment. This project aims to investigate the capability of micro end-milling process of Inconel 718 with minimum quantity lubrication (MQL). Microtools DT-110 multi-process micro machine was used to machine 10 micro-channels with MQL and 10 more under dry condition while maintaining the same machining parameters. The width of the micro-channels was measured using digital microscope and used to determine the process capability indices, Cp and Cpk. QI Macros SPC for Excel was used to analyze the resultant machining data. The results indicated that micro end-milling process of Inconel 718 was not capable under both MQL and dry cutting conditions as indicated by the Cp values of less than 1.0. However, the use of MQL helped the process to be more stable and capable. Results obtained showed that the process variation was greatly reduced by using MQL in micro end-milling of Inconel 718.

  19. Capabilities for measuring physical and chemical properties of rocks at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B. (comp.)

    1990-01-01

    The Experimental Geophysics Group of the Earth Sciences Department at Lawrence Livermore National Laboratory (LLNL) has experimental equipment that measures a variety of physical properties and phase equilibria and kinetics on rocks and minerals at extreme pressures (to 500 GPa) and temperatures (from 10 to 2800 K). These experimental capabilities are described in this report in terms of published results, photographs, and schematic diagrams.

  20. Analytical Capability of Defocused µ-SORS in the Chemical Interrogation of Thin Turbid Painted Layers.

    Science.gov (United States)

    Conti, Claudia; Realini, Marco; Botteon, Alessandra; Colombo, Chiara; Noll, Sarah; Elliott, Stephen R; Matousek, Pavel

    2016-01-01

    A recently developed micrometer-scale spatially offset Raman spectroscopy (μ-SORS) method provides a new analytical capability for investigating non-destructively the chemical composition of sub-surface, micrometer-scale thickness, diffusely scattering layers at depths beyond the reach of conventional confocal Raman microscopy. Here, we demonstrate experimentally, for the first time, the capability of μ-SORS to determine whether two detected chemical components originate from two separate layers or whether the two components are mixed together in a single layer. Such information is important in a number of areas, including conservation of cultural heritage objects, and is not available, for highly turbid media, from conventional Raman microscopy, where axial (confocal) scanning is not possible due to an inability to facilitate direct imaging within the highly scattering sample. This application constitutes an additional capability for μ-SORS in addition to its basic capacity to determine the overall chemical make-up of layers in a turbid system.

  1. In Situ Analysis of a High-Temperature Cure Reaction in Real Time Using Modulated Fiber-Optic FT-Raman Spectroscopy

    Science.gov (United States)

    Aust, Jeffrey F.; Cooper, John B.; Wise, Kent L.; Jensen, Brian J.

    1999-01-01

    The vibrational spectrum of a high-temperature (330 C) polymerization reaction was successfully monitored in real time with the use of a modulated fiber-optic Fourier transform (FT)-Raman spectrometer. A phenylethynyl-terminated monomer was cured, and spectral evidence for two different reaction products was acquired. The products are a conjugated polyene chain and a cyclized trimer. This is the first report describing the use of FT-Raman spectroscopy to monitor a high temperature (greater than 250 C) reaction in real time.

  2. In situ Raman spectroscopic analysis of surface oxide films on Ni-base alloy/low alloy steel dissimilar metal weld interfaces in high-temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongjin; Choi, Kyung Joon [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of); Bahn, Chi Bum [School of Mechanical Engineering, Pusan National University 2, 63-gil, Geumjeong-Gu, Pusan 609-735 (Korea, Republic of); Kim, Ji Hyun, E-mail: kimjh@unist.ac.kr [School of Mechanical and Nuclear Engineering, Ulsan National Institute of Science and Technology (UNIST), 100 Banyeon-ri, Eonyang-eup, Ulju-gun, Ulsan 689-798 (Korea, Republic of)

    2014-06-01

    In situ Raman spectroscopy has been applied to analyze the surface oxide films formed on dissimilar metal weld (DMW) interfaces of nickel-base alloy/low alloy steel under hydrogenated high-temperature water condition. For the analysis of the oxide films under high temperature/pressure aqueous conditions, an in situ Raman spectroscopy system was developed by constructing a hydrothermal cell where the entire optics including the excitation laser and the Raman light collection system were located at the nearest position to the specimen by means of immersion optics. In situ Raman spectra of the DMW interfaces were collected in hydrogenated water condition at different temperatures up to 300 °C. The measured in situ Raman spectra showed peaks of Cr{sub 2}O{sub 3}, NiCr{sub 2}O{sub 4} and Fe{sub 3}O{sub 4} at the DMW interface. It is considered that differences in the oxide chemistry originated from the chemical element distribution inside of the DMW interface region.

  3. Surface-Enhanced Raman Spectroscopy Based Quantitative Bioassay on Aptamer-Functionalized Nanopillars Using Large-Area Raman Mapping

    DEFF Research Database (Denmark)

    Yang, Jaeyoung; Palla, Mirko; Bosco, Filippo

    2013-01-01

    Surface-enhanced Raman spectroscopy (SERS) has been used in a variety of biological applications due to its high sensitivity and specificity. Here, we report a SERS-based biosensing approach for quantitative detection of biomolecules. A SERS substrate bearing gold-decorated silicon nanopillars......-to-spot variation in conventional SERS quantification. Furthermore, we have developed an analytical model capable of predicting experimental intensity distributions on the substrates for reliable quantification of biomolecules. Lastly, we have calculated the minimum needed area of Raman mapping for efficient...

  4. New Modelling Capabilities in Commercial Software for High-Gain Antennas

    DEFF Research Database (Denmark)

    Jørgensen, Erik; Lumholt, Michael; Meincke, Peter

    2012-01-01

    type of EM software tool aimed at extending the ways engineers can use antenna measurements in the antenna design process. The tool allows reconstruction of currents and near fields on a 3D surface conformal to the antenna, by using the measured antenna field as input. The currents on the antenna......This paper presents an overview of selected new modelling algorithms and capabilities in commercial software tools developed by TICRA. A major new area is design and analysis of printed reflectarrays where a fully integrated design environment is under development, allowing fast and accurate...... characterization of the reflectarray element, an initial phaseonly synthesis, followed by a full optimization procedure taking into account the near-field from the feed and the finite extent of the array. Another interesting new modelling capability is made available through the DIATOOL software, which is a new...

  5. Highly Sensitive Detection of Clenbuterol in Animal Urine Using Immunomagnetic Bead Treatment and Surface-Enhanced Raman Spectroscopy

    Science.gov (United States)

    Cheng, Jie; Su, Xiao-Ou; Wang, Shi; Zhao, Yiping

    2016-09-01

    Combining surface-enhanced Raman spectroscopy (SERS) of aggregated graphene oxide/gold nanoparticle hybrids with immunomagnetic bead sample preparation method, a highly sensitive strategy to determine the clenbuterol content in animal urine was developed. Based on a linear calibration curve of the SERS characteristic peak intensity of clenbuterol at Δv = 1474 cm-1 versus the spiked clenbuterol concentration in the range of 0.5-20 ng·mL-1, the quantity of clenbuterol in real animal urine samples can be determined and matches well with those determined by LC-MS/MS, while the detection time is significantly reduced to 15 min/sample. The limits of detection and quantification in the urine are 0.5 ng·mL-1 and 1 ng·mL-1, respectively, and the recovery clenbuterol rates are 82.8-92.4% with coefficients of variation animal farming.

  6. Femtosecond double-pulse fabrication of hierarchical nanostructures based on electron dynamics control for high surface-enhanced Raman scattering.

    Science.gov (United States)

    Zhang, Ning; Li, Xin; Jiang, Lan; Shi, Xuesong; Li, Cong; Lu, Yongfeng

    2013-09-15

    This Letter presents a simple, efficient approach for high surface-enhanced Raman scattering by one-step controllable fabrication of hierarchical structures (nanoparticles+subwavelength ripples) on silicon substrates in silver nitrate solutions using femtosecond double pulses based on nanoscale electron dynamics control. As the delays of the double pulses increase from 0 fs to 1 ps, the hierarchical structures can be controlled with (1) nanoparticles--the number of nanoparticles in the range of 40-100 nm reaches the maximum at 800 fs and (2) ripples--the subwavelength ripples become intermittent with decreased ablation depths. The redistributed nanoparticles and the modified ripple structures contribute to the maximum enhancement factor of 2.2×10(8) (measured by 10(-6)  M rhodamine 6G solution) at the pulse delay of 800 fs.

  7. A stimulated Raman scattering imager using high-speed lateral electric field modulator and lock-in pixels amplifiers

    Science.gov (United States)

    Mars, Kamel; Guseul, Beak; Han, Sang Man; Takasawa, Taishi; Yasutomi, Keita; Kagawa, Keiichiro; Hashimoto, Mamoru; Kawahito, Shoji

    2014-03-01

    A high speed Lateral Electric Field Modulator (LEFM) and lock-in pixels amplifiers for stimulated Raman scattering (SRS)imager is presented. Since the generated signal from the SRS process is very small compared to the offset signal, a technique suitable for extracting and amplifying the SRS signal is needed. The offset can be canceled by tuning the phase delay between the demodulated pixel output signal and the sampling clock. The small SRS signal in large offset is amplified by the differential integration. The proposed technique has been investigated with an implementation of 64x8 pixels array using a pinned photodiode LEFM an lock-in pixels amplifiers. Very small signal can be extracted from large offset signal. A ratio of the detected small SRS to offset signal of less 10-5 is achieved.

  8. High resolution AFM and single cell resonance Raman spectroscopy of Geobacter sulfurreducens biofilms early in growth.

    Directory of Open Access Journals (Sweden)

    Nikolai eLebedev

    2014-08-01

    Full Text Available AFM and confocal resonance Raman microscopy (CRRM of single-cells were used to study the transition of anode-grown Geobacter sulfurreducens biofilms from lag phase (initial period of low current to exponential phase (subsequent period of rapidly increasing current. Results reveal that lag phase biofilms consist of lone cells and tightly packed single-cell thick clusters crisscrossed with extracellular linear structures that appear to be comprised of nodules approximately 20 nm in diameter aligned end to end. By early exponential phase cell clusters expand laterally and a second layer of closely packed cells begins to form on top of the first. Abundance of c-type cytochromes (c-Cyt is > 3-fold greater in 2-cell thick regions than in 1-cell thick regions. The results indicate that early biofilm growth involves two transformations. The first is from lone cells to 2-dimensionally associated cells during lag phase when current remains low. This is accompanied by formation of extracellular linear structures. The second is from 2- to 3-dimensionally associated cells during early exponential phase when current begins to increases rapidly. This is accompanied by a dramatic increase in c-Cyt abundance.

  9. Silver nanoaggregates on chitosan functionalized graphene oxide for high-performance surface-enhanced Raman scattering.

    Science.gov (United States)

    Wan, Mingming; Liu, Zhiming; Li, Shaoxin; Yang, Biwen; Zhang, Wen; Qin, Xiaochu; Guo, Zhouyi

    2013-07-01

    Herein we describe a self-assembly synthesis of graphene oxide/Ag nanoparticles nano-composites (GO/CS/AgNPs) by non-covalent attachment of AgNPs to chitosan (CS) functionalized graphene oxide (GO) sheets. The negatively charged AgNPs are prone to form aggregates on GO/CS via electrostatic interaction, which is extremely beneficial to the surface-enhanced Raman scattering (SERS) detection of aromatic molecules. Taking advantage of the enrichment of target molecules on GO, the obtained hybrids exhibit strong SERS activity to aromatic molecules (trypan blue and methylene blue). Furthermore, SERS signals of a negatively charged molecule (trypan blue) are stronger than signals of a positively charged molecule (methylene blue) due to the different adsorption capacity of GO/CS/AgNPs for the two opposite charged molecules through electrostatic interaction. Moreover, GO/CS/AgNPs remarkably enhance the main peaks of l-phenylalanine, in comparison with the silver nanoparticles, showing great potential for biomedical applications.

  10. High-pressure Fourier transform micro-Raman spectroscopic investigation of diiodine-heterocyclic thioamide adducts.

    Science.gov (United States)

    dos Santos, João Henrique Z; Butler, Ian S; Daga, Vasiliki; Hadjikakou, Sotiris; Hadjiliadis, Nick

    2002-10-01

    The pressure dependences of the Fourier transform micro-Raman spectra of four heterocyclic thioamides [[(bztzdtH)I2] x I2] (1) (bztzdtH = benzothiazole-2-thione), [(bztzdtH)I2] (2), [[(tzdtH)2I+] x I3- x 2I2] (3) (tzdtH = thiazoline-2-thione), and [[(bzimtH)I2]2 x I2 x 2H2O] (4) (bzimtH = benzimidazole-2-thione) have been studied between ambient pressure and 50 kbar. For 1, generation of I3- ions through disproportionation reactions is evident as the pressure is increased. There are empirical linear correlations between the frequency and (I-I) bond length and the applied pressure. The iodine adduct of thioamide 2 is more sensitive to pressure when compared to the 1 or 4 iodine adducts. This difference in behavior may be attributed to differences in crystal structures or to a lower I-I bond order. Monitoring of other vibrational transitions of the thiomide structure reveals several less important pressure dependences.

  11. Mechanism of Surface-Enhanced Raman Scattering and Its Application to Highly Sensitive Protein Detection

    Institute of Scientific and Technical Information of China (English)

    Ozaki Y; Itoh T; Yoshida K; Kitahama y; Han X X; Zhao B

    2009-01-01

    @@ Surface-enhanced resonance Raman scattering(SERRS)has recently attracted great interest in analytical science due to enormous enhancement factors that have decreased the detection limits of a wide variety of molecules tO the single molecule level.The SERRS-electromagnetic(EM)model describes single-molecule SERRS sensitivity at interparticle junctions and at sharp edges in Ag and Au nanoaggregatcs based on the fourth power of a local EM-field enhancement factor M The realization of SERRS enhancement factors |M|4 of up to 1014has made single-molecule sensitivity realistic.In other words,twofold EM enhancement processes are important for verifying SERRS enhancement factors that enable single molecules to be detected:in these processes the first enhancement iS due to coupling between incident photons and plasmons and the second enhancement is due tO coupling between SERRS photons and plasmons.The relationship between plasmon resonance,the SERRS intensity,and Ag-nanoparticle microstructures was comprehensively studied to verify EM enhancement in SERRS.However,the first and second enhancements were not treated independently in these investigations and thus they were not able tO provide conclusive evidence for twofold EM enhancements.

  12. High-pressure Raman and x-ray study of the spin-frustrated pyrochlore Gd2Ti2O7

    Science.gov (United States)

    Saha, Surajit; Muthu, D. V. S.; Pascanut, C.; Dragoe, N.; Suryanarayanan, R.; Dhalenne, G.; Revcolevschi, A.; Karmakar, Sukanta; Sharma, Surinder M.; Sood, A. K.

    2006-08-01

    Pressure-dependent Raman and x-ray diffraction studies of spin-frustrated pyrochlore Gd2Ti2O7 have been carried out at room temperature up to ˜25GPa and 34GPa , respectively. A subtle distortion of the lattice at about 9GPa is evidenced by Raman spectroscopy. X-ray results corroborate the distortion of the pyrochlore lattice at about the same pressure. Shell model lattice dynamical calculations were carried out in order to establish and understand the pressure dependence of Raman phonon frequencies. Our data may be relevant to the recent findings by Mirebeau [Nature 420, 54 (2002)] who observed magnetic correlations under high pressure in Tb2Ti2O7 , a frustrated spin-liquid system.

  13. Raman imaging of grain growth mechanism in highly textured Pb(Mg{1{/}3}Nb{2{/}3})O{3}-PbTiO{3} piezoelectric ceramics*

    Science.gov (United States)

    Colomban, P.; Pham Thi, Mai

    2005-06-01

    Pb(Mg{1 / 3}Nb{2 / 3})O{3}-PbTiO{3} solid solution ((1-x)PMN-xPT) tape cast ceramics have been prepared by homo-epitaxial templated grain growth (HTGG) using cubic 0.75PMN 0.25 PT single crystal seeds as template (a few wt%) and x = 0.35 nanoparticles for the ceramic matrix. Raman imaging studied representative medium and highly textured ceramics. On the base of a previous study which has shown that the Raman peak centre of gravity depends on the solid solution composition whereas peak intensity is correlated to the unit-cell distortion, Raman imaging shows that the final composition and structure is very close to that of the matrix.

  14. Rapid and large-scale synthesis of pitaya-like silver nanostructures as highly efficient surface-enhanced Raman scattering substrates.

    Science.gov (United States)

    Huang, Qingli; Zhu, Xiashi

    2013-02-15

    A new wet-chemical approach to prepare surface-enhanced Raman scattering (SERS)-active substrates with pitaya-like silver nanostructures (PSNs) was proposed. It has been found that the morphology of as-prepared products is dependent on the reaction parameters. PSNs exhibit a high detection sensitivity of surface-enhanced Raman scattering for Rhodamine 6G (R6G) with a limit of detection of 1.0 × 10(-13) mol L(-1). This facile, large-scale, low-cost, and green chemistry synthesized Ag nanostructures make it a perfect choice for practical SERS detection applications.

  15. A new high strength stainless maraging spring steel with isotropic shaping capability

    Energy Technology Data Exchange (ETDEWEB)

    Weber, H.R. [VACUUMSCHMELZE GmbH+Co. KG, Hanau (Germany)

    2001-09-01

    The production of complex shapes coupled with the demand for maximum final strength is called for by many design engineers in the fields of components, springs or elements for control technology, pneumatics, and hydraulics in order to meet the increasing trend to miniaturization and reducing the number of parts. A new FeNiCoMo-based maraging steel succeeds in combining the maximum strengths and isotropic shaping capability of non-stainless maraging steels with the anti-corrosive properties of austenitic CrNi steels. (orig.)

  16. High-level interface to T-matrix scattering calculations: architecture, capabilities and limitations.

    Science.gov (United States)

    Leinonen, Jussi

    2014-01-27

    The PyTMatrix package was designed with the objective of providing a simple, extensible interface to T-Matrix electromagnetic scattering calculations performed using an extensively validated numerical core. The interface, implemented in the Python programming language, facilitates automation of the calculations and further analysis of the results through direct integration of both the inputs and the outputs of the calculations to numerical analysis software. This article describes the architecture and design of the package, illustrating how the concepts in the physics of electromagnetic scattering are mapped into data and code models in the computer software. The resulting capabilities and their consequences for the usability and performance of the package are explored.

  17. Time-Encoded Raman: Fiber-based, hyperspectral, broadband stimulated Raman microscopy

    CERN Document Server

    Karpf, Sebastian; Wieser, Wolfgang; Klein, Thomas; Huber, Robert

    2014-01-01

    Raman sensing and Raman microscopy are amongst the most specific optical technologies to identify the chemical compounds of unknown samples, and to enable label-free biomedical imaging with molecular contrast. However, the high cost and complexity, low speed, and incomplete spectral information provided by current technology are major challenges preventing more widespread application of Raman systems. To overcome these limitations, we developed a new method for stimulated Raman spectroscopy and Raman imaging using continuous wave (CW), rapidly wavelength swept lasers. Our all-fiber, time-encoded Raman (TICO-Raman) setup uses a Fourier Domain Mode Locked (FDML) laser source to achieve a unique combination of high speed, broad spectral coverage (750 cm-1 - 3150 cm-1) and high resolution (0.5 cm-1). The Raman information is directly encoded and acquired in time. We demonstrate quantitative chemical analysis of a solvent mixture and hyperspectral Raman microscopy with molecular contrast of plant cells.

  18. Lidar Observations of Tropical High-altitude Cirrus Clouds: Results form Dual Wavelength Raman Lidar Measurements During the ALBATROSS Campaign 1996

    Science.gov (United States)

    Neuber, R.; Wegener, Alfred; Schrems, O.; McDermid, I. S.

    1997-01-01

    Results from dual wavelength Raman Lidar Observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus cloud were present in more than 50% of the observations at latitudes between 23.5 degress S and 23.5 degrees N and altitudes between 11 and 16km.

  19. Lidar Observations of Tropical High-altitude Cirrus Clouds: Results form Dual Wavelength Raman Lidar Measurements During the ALBATROSS Campaign 1996

    Science.gov (United States)

    Neuber, R.; Wegener, Alfred; Schrems, O.; McDermid, I. S.

    1997-01-01

    Results from dual wavelength Raman Lidar Observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus cloud were present in more than 50% of the observations at latitudes between 23.5 degress S and 23.5 degrees N and altitudes between 11 and 16km.

  20. Raman fiber lasers

    Science.gov (United States)

    Supradeepa, V. R.; Feng, Yan; Nicholson, Jeffrey W.

    2017-02-01

    High-power fiber lasers have seen tremendous development in the last decade, with output powers exceeding multiple kilowatts from a single fiber. Ytterbium has been at the forefront as the primary rare-earth-doped gain medium owing to its inherent material advantages. However, for this reason, the lasers are largely confined to the narrow emission wavelength region of ytterbium. Power scaling at other wavelength regions has lagged significantly, and a large number of applications rely upon the diversity of emission wavelengths. Currently, Raman fiber lasers are the only known wavelength agile, scalable, high-power fiber laser technology that can span the wavelength spectrum. In this review, we address the technology of Raman fiber lasers, specifically focused on the most recent developments. We will also discuss several applications of Raman fiber lasers in laser pumping, frequency conversion, optical communications and biology.

  1. Next generation hazard detection via ultrafast coherent anti-Stokes Raman spectroscopy

    Science.gov (United States)

    Brady, John J.; Pellegrino, Paul M.

    2013-05-01

    Multiplex coherent anti-Stokes Raman spectroscopy (MCARS) is used to detect an explosive precursor material and two chemical warfare simulants. The spectral bandwidth of the femtosecond laser pulse used in these studies is sufficient to coherently and simultaneously drive all the vibrational modes in the molecule of interest. The research performed here demonstrates that MCARS has the capability to detect an explosive precursor (e.g., acetone) and hazardous materials, such as dimethyl methylphosphonate and 2-chloroethyl methyl sulfide (a sarin and a mustard gas chemical warfare simulant, respectively), with high specificity. Evidence shows that MCARS is capable of overcoming common the sensitivity limitations of spontaneous Raman scattering, thus allowing for the detection of the target material in milliseconds with standard USB spectrometers as opposed to seconds with intensified spectrometers. The exponential increase in the number of scattered photons suggests that the MCARS technique may be capable of overcoming range detection challenges common to spontaneous Raman scattering.

  2. Exploring many body interactions with Raman spectroscopy

    Science.gov (United States)

    Tian, Yao

    analysis. Then, a wavelet transform and data clustering based spike-removal algorithm is proposed to resolve the erroneous spikes caused by cosmic rays in Raman spectra. Data sets from real measurements were analyzed to demonstrate the capability of the algorithm. Finally, the results of a minor project are presented. Thin lms of the high dielectric material SrTiO3 grown via a new method on silicon(100) are studied by ellipsometry. The results suggest that two layers of SrTiO3 are formed during the growth.

  3. Advances in Raman spectroscopy for In Situ Identification of Minerals and Organics on Diverse Planetary Surfaces: from Mars to Titan

    Science.gov (United States)

    Blacksberg, J.; Alerstam, E.; Maruyama, Y.; Cochrane, C.; Rossman, G. R.

    2015-12-01

    We present recent developments in time-resolved Raman spectroscopy for in situ planetary surface exploration, aimed at identification of both minerals and organics. Raman is a non-destructive surface technique that requires no sample preparation. Raman spectra are highly material specific and can be used for identification of a wide range of unknown samples. In combination with micro-scale imaging and point mapping, Raman spectroscopy can be used to directly interrogate rocks and regolith materials, while placing compositional analyses within a microtextural context, essential for understanding surface evolutionary pathways. Due to these unique capabilities, Raman spectroscopy is of great interest for the exploration of all rocky and icy bodies, for example Mars, Venus, the Moon, Mars' moons, asteroids, comets, Europa, and Titan. In this work, we focus on overcoming one of the most difficult challenges faced in Raman spectroscopy: interference from background fluorescence of the very minerals and organics that we wish to characterize. To tackle this problem we use time-resolved Raman spectroscopy, which separates the Raman from background processes in the time domain. This same technique also enables operation in daylight without the need for light shielding. Two key components are essential for the success of this technique: a fast solid-state detector and a short-pulse laser. Our detector is a custom developed Single Photon Avalanche Diode (SPAD) array, capable of sub-ns time-gating. Our pulsed lasers are solid-state miniature pulsed microchip lasers. We discuss optimization of laser and detector parameters for our application. We then present Raman spectra of particularly challenging planetary analog samples to demonstrate the unique capabilities of this time-resolved Raman instrument, for example, Mars-analog clays and Titan-analog organics. The research described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a

  4. Capability Paternalism

    NARCIS (Netherlands)

    Claassen, R.J.G.

    2014-01-01

    A capability approach prescribes paternalist government actions to the extent that it requires the promotion of specific functionings, instead of the corresponding capabilities. Capability theorists have argued that their theories do not have much of these paternalist implications, since promoting c

  5. Dual Raman-Brillouin Microscope for Chemical and Mechanical Characterization and Imaging.

    Science.gov (United States)

    Traverso, Andrew J; Thompson, Jonathan V; Steelman, Zachary A; Meng, Zhaokai; Scully, Marlan O; Yakovlev, Vladislav V

    2015-08-01

    We present a unique confocal microscope capable of measuring the Raman and Brillouin spectra simultaneously from a single spatial location. Raman and Brillouin scattering offer complementary information about a material's chemical and mechanical structure, respectively, and concurrent monitoring of both of these spectra would set a new standard for material characterization. We achieve this by applying recent innovations in Brillouin spectroscopy that reduce the necessary acquisition times to durations comparable to conventional Raman spectroscopy while attaining a high level of spectral accuracy. To demonstrate the potential of the system, we map the Raman and Brillouin spectra of a molded poly(ethylene glycol) diacrylate (PEGDA) hydrogel sample in cyclohexane to create two-dimensional images with high contrast at microscale resolutions. This powerful tool has the potential for very diverse analytical applications in basic science, industry, and medicine.

  6. Research on high rate capabilities B-substituted LiFePO4.

    Science.gov (United States)

    Wang, Fu; Zhang, Yun; Chen, Chao

    2013-02-01

    LiFePO4 is currently recognized as one of the most promising electrode materials for large-scale application of lithium ion batteries. However, the limitation of rate capability is believed to be intrinsic to this family of compounds due to the existence of larger tetrahedral (PO4)3- unit and quasi-hexagonal close-packed oxygen array. This paper report here a systematic investigation of the enhancement of rate performance by partly substitution of light small triangle oxyanion, (BO3)3-, for the larger tetrahedral (PO4)3- units in LiFePO4. Cathode electrode materials LiFeB(x)P(1_x)O(4-delta), in which X = 0, 3, 6 and 9, mol%, were synthesized by solid-state method. The as-synthesized products were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM) and Electrochemical Measurements. The results showed that 6 mol% of boron substitution had no effect on the structure of LiFePO4 material, but significantly improved its rate performance. The initial discharge capacity of the LiFeB0.06P0.94O(4-delta) sample was 145.62 mAh/g at 0.1 C, and the capacity retention ratios of 81% at 2 C and 76% at 5 C were obtained, demonstrating that a proper amount of boron substitution (lower than 6 mol%) could significantly improve the rate performance of LiFePO4 cathode material.

  7. High-density automotive hydrogen storage with cryogenic capable pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, Salvador M.; Espinosa-Loza, Francisco; Ledesma-Orozco, Elias; Ross, Timothy O.; Weisberg, Andrew H. [Lawrence Livermore National Laboratory, P.O. Box 808, L-792, Livermore, CA 94551 (United States); Brunner, Tobias C.; Kircher, Oliver [BMW Group, Knorrstr. 147, 80788 Munich (Germany)

    2010-02-15

    LLNL is developing cryogenic capable pressure vessels with thermal endurance 5-10 times greater than conventional liquid hydrogen (LH{sub 2}) tanks that can eliminate evaporative losses in routine usage of (L)H{sub 2} automobiles. In a joint effort BMW is working on a proof of concept for a first automotive cryo-compressed hydrogen storage system that can fulfill automotive requirements on system performance, life cycle, safety and cost. Cryogenic pressure vessels can be fueled with ambient temperature compressed gaseous hydrogen (CGH{sub 2}), LH{sub 2} or cryogenic hydrogen at elevated supercritical pressure (cryo-compressed hydrogen, CcH{sub 2}). When filled with LH{sub 2} or CcH{sub 2}, these vessels contain 2-3 times more fuel than conventional ambient temperature compressed H{sub 2} vessels. LLNL has demonstrated fueling with LH{sub 2} onboard two vehicles. The generation 2 vessel, installed onboard an H{sub 2}-powered Toyota Prius and fueled with LH{sub 2} demonstrated the longest unrefueled driving distance and the longest cryogenic H{sub 2} hold time without evaporative losses. A third generation vessel will be installed, reducing weight and volume by minimizing insulation thickness while still providing acceptable thermal endurance. Based on its long experience with cryogenic hydrogen storage, BMW has developed its cryo-compressed hydrogen storage concept, which is now undergoing a thorough system and component validation to prove compliance with automotive requirements before it can be demonstrated in a BMW test vehicle. (author)

  8. Wavelength-Dependent Transient Characteristics Caused by Gain Saturation in Highly Nonlinear Fiber-Based Raman Amplifiers

    Institute of Scientific and Technical Information of China (English)

    Shinobu; Tamaoki; Tetsufumi; Tsuzaki; Motoki; Kakui; Masayuki; Shigematsu

    2003-01-01

    We have investigated the transient characteristics of discrete Raman Amplifiers and found that the response time caused by gain saturation is dependent upon the wavelength, which corresponds to the effective length of the pump light.

  9. Influence of the Magnetic High-speed Steel Cutting Tool on Cutting Capability

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The high-speed steel cutting tool has advantaged i n modern cutting tool for its preferable synthetical performance, especially, in a pplication of complicated cutting tools. Therefore, the study of the high-speed steel cutting tools that occupied half of cutting tools has become an importa nt way of studying on modern cutting technology. The cutting performance of hi gh speed-steel cutting tools will be improved by magnetization treating method. Microstructure of high-speed steel will be changed as a ...

  10. Construction of a high resolution microscope with conventional and holographic optical trapping capabilities.

    Science.gov (United States)

    Butterfield, Jacqualine; Hong, Weili; Mershon, Leslie; Vershinin, Michael

    2013-04-22

    High resolution microscope systems with optical traps allow for precise manipulation of various refractive objects, such as dielectric beads (1) or cellular organelles (2,3), as well as for high spatial and temporal resolution readout of their position relative to the center of the trap. The system described herein has one such "traditional" trap operating at 980 nm. It additionally provides a second optical trapping system that uses a commercially available holographic package to simultaneously create and manipulate complex trapping patterns in the field of view of the microscope (4,5) at a wavelength of 1,064 nm. The combination of the two systems allows for the manipulation of multiple refractive objects at the same time while simultaneously conducting high speed and high resolution measurements of motion and force production at nanometer and piconewton scale.

  11. WAHRSIS: A Low-cost, High-resolution Whole Sky Imager With Near-Infrared Capabilities

    CERN Document Server

    Dev, Soumyabrata; Lee, Yee Hui; Winkler, Stefan

    2016-01-01

    Cloud imaging using ground-based whole sky imagers is essential for a fine-grained understanding of the effects of cloud formations, which can be useful in many applications. Some such imagers are available commercially, but their cost is relatively high, and their flexibility is limited. Therefore, we built a new daytime Whole Sky Imager (WSI) called Wide Angle High-Resolution Sky Imaging System. The strengths of our new design are its simplicity, low manufacturing cost and high resolution. Our imager captures the entire hemisphere in a single high-resolution picture via a digital camera using a fish-eye lens. The camera was modified to capture light across the visible as well as the near-infrared spectral ranges. This paper describes the design of the device as well as the geometric and radiometric calibration of the imaging system.

  12. High Energy Hadron Colliders - Report of the Snowmass 2013 Frontier Capabilities Hadron Collider Study Group

    CERN Document Server

    Barletta, William; Battaglia, Marco; Klute, Markus; Mangano, Michelangelo; Prestemon, Soren; Rossi, Lucio; Skands, Peter

    2013-01-01

    High energy hadron colliders have been the tools for discovery at the highest mass scales of the energy frontier from the SppS, to the Tevatron and now the LHC. This report reviews future hadron collider projects from the high luminosity LHC upgrade to a 100 TeV hadron collider in a large tunnel, the underlying technology challenges and R&D directions and presents a series of recommendations for the future development of hadron collider research and technology.

  13. Turbo system technology for downsized high volume engines with PZEV capability

    Energy Technology Data Exchange (ETDEWEB)

    Bjoernsson, Haakan; Johansson, Lena [Volvo Car Corp., Gothenburg (Sweden)

    2008-07-01

    Turbo charging is not anymore only used for exotic high performance vehicles. Instead boosting technology will be used to provide high specific power output, reduced fuel consumption and consequently lower CO2 emissions for all types of vehicles in the future. The main reason for this change is the obvious need for a shift towards more fuel efficient down-sized engines which output that enables a lower fuel consumption. This new way of using turbo charging introduces a new set of demands which needs to be fulfilled before this technology can be applied efficiently in to mass production. Since one of the most basic down-sizing features is a high specific low end torque with an associated excellent transient behavior at low speeds, the overall charging efficiency, must be high over a broad speed and load range. The down-sizing effect also imply a more frequent use of the high specific power, which means that smaller engines needs to cope with a high exhaust gas temperature more often. High specific power output also has to be combined with strict US and EC emission legislation i.e. fulfillment of PZEV and Euro 6 emissions. This will add new challenges to turbo system development. Simultaneously, material prices have increased significantly over the last five years. Unfortunately, these new requirements have a tendency to push the piece price in the wrong direction, which means that down-sizing have a tendency to add high on-cost to the most price sensitive products. Therefore, the aim of this paper is to discuss possible solutions for future turbo system technology. (orig.)

  14. Highly selective and sensitive surface enhanced Raman scattering nanosensors for detection of hydrogen peroxide in living cells.

    Science.gov (United States)

    Qu, Lu-Lu; Liu, Ying-Ya; He, Sai-Huan; Chen, Jia-Qing; Liang, Yuan; Li, Hai-Tao

    2016-03-15

    Determination of hydrogen peroxide (H2O2) with high sensitivity and selectivity in living cells is a challenge for evaluating the diverse roles of H2O2 in the physiological and pathological processes. In this work, we present novel surface enhanced Raman scattering (SERS) nanosensors, 4-carboxyphenylboronic acid (4-CA) modified gold nanoparticles (Au NPs/4-CA), for sensing H2O2 in living cells. The nanosensors are based on that the H2O2-triggered oxidation reaction with the arylboronate on Au NPs would liberate the phenol, thus causing changes of the SERS spectra of the nanosensors. The results show the nanosensors feature higher selectivity for H2O2 over other reactive oxygen species, abundant competing cellular thiols and biologically relevant species, as well as excellent sensitivity with a low detection limit of 80 nM, which fulfills the requirements for detection of H2O2 in a biological system. In addition, the SERS nanosensors exhibit long term stability against time and pH, and high biocompatibility. More importantly, the presented nanosensors can be successfully used for monitoring changes of H2O2 levels within living biological samples upon oxidative stress, which opens up new opportunities to study its cellular biochemistry.

  15. Flexible nano-felts of carbide-derived carbon with ultra-high power handling capability

    Energy Technology Data Exchange (ETDEWEB)

    Presser, Volker; Zhang, Lifeng; Niu, Jun Jie; McDonough, John; Perez, Carlos; Gogotsi, Yury [Department of Materials Science and Engineering and A.J. Drexel, Nanotechnology Institute, Drexel University, Philadelphia, PA 19104 (United States); Fong, Hao [Department of Chemistry, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States)

    2011-05-15

    Nano-fibrous felts (nano-felts) of carbide-derived carbon (CDC) have been developed from the precursor of electrospun titanium carbide (TiC) nano-felts. Conformal transformation of TiC into CDC conserves main features of the precursor including the high interconnectivity and structural integrity; the developed TiC-CDC nano-felts are mechanically flexible/resilient, and can be used as electrode material for supercapacitor application without the addition of any binder. After synthesis through chlorination of the precursor at 600 C, the TiC-CDC nano-fibers show an average pore size of {proportional_to}1nm, a high specific surface area of 1390 m{sup 2}/g; and the nano-fibers have graphitic carbon ribbons embedded in a highly disordered carbon matrix. Graphitic carbon is preserved from the precursor nano-fibers where a few graphene layers surround TiC nanocrystallites. Electrochemical measurements show a high gravimetric capacitance of 110 F/g in aqueous electrolyte (1 M H{sub 2}SO{sub 4}) and 65 F/g in organic electrolyte (1.5 M TEA-BF{sub 4} in acetonitrile). Because of the unique microstructure of TiC-CDC nano-felts, a fade of the capacitance of merely 50% at a high scan rate of 5 V/s is observed. A fade of just 15% is observed for nano-felt film electrodes tested in 1 M H{sub 2} SO{sub 4} at 1 V/s, resulting in a high gravimetric capacitance of 94 F/g. Such a high rate performance is only known for graphene or carbon-onion based supercapacitors, whereas binders have to be used for the fabrication of those supercapacitors. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Blood analysis by Raman spectroscopy

    Science.gov (United States)

    Enejder, Annika M. K.; Koo, Tae-Woong; Oh, Jeankun; Hunter, Martin; Sasic, Slobodan; Feld, Michael S.; Horowitz, Gary L.

    2002-11-01

    Concentrations of multiple analytes were simultaneously measured in whole blood with clinical accuracy, without sample processing, using near-infrared Raman spectroscopy. Spectra were acquired with an instrument employing nonimaging optics, designed using Monte Carlo simulations of the influence of light-scattering-absorbing blood cells on the excitation and emission of Raman light in turbid medium. Raman spectra were collected from whole blood drawn from 31 individuals. Quantitative predictions of glucose, urea, total protein, albumin, triglycerides, hematocrit, and hemoglobin were made by means of partial least-squares (PLS) analysis with clinically relevant precision (r2 values >0.93). The similarity of the features of the PLS calibration spectra to those of the respective analyte spectra illustrates that the predictions are based on molecular information carried by the Raman light. This demonstrates the feasibility of using Raman spectroscopy for quantitative measurements of biomolecular contents in highly light-scattering and absorbing media.

  17. All-Fiber Raman Probe

    DEFF Research Database (Denmark)

    Brunetti, Anna Chiara

    The design and development of an all-in-fiber probe for Raman spectroscopy are presented in this Thesis. Raman spectroscopy is an optical technique able to probe a sample based on the inelastic scattering of monochromatic light. Due to its high specificity and reliability and to the possibility...... to perform real-time measurements with little or no sample preparation, Raman spectroscopy is now considered an invaluable analytical tool, finding application in several fields including medicine, defense and process control. When combined with fiber optics technology, Raman spectroscopy allows...... for the realization of flexible and minimally-invasive devices, able to reach remote or hardly accessible samples, and to perform in-situ analyses in hazardous environments. The work behind this Thesis focuses on the proof-of-principle demonstration of a truly in-fiber Raman probe, where all parts are realized...

  18. Soret Effect Study on High-Pressure CO2-Water Solutions Using UV-Raman Spectroscopy and a Concentric-Tube Optical Cell

    Energy Technology Data Exchange (ETDEWEB)

    Windisch, Charles F.; McGrail, B. Peter; Maupin, Gary D.

    2012-01-01

    Spatially resolved deep-UV Raman spectroscopy was applied to solutions of CO2 and H2O (or D2O), which were subject to a temperature gradient in a thermally regulated high-pressure concentric-tube Raman cell in an attempt to measure a Soret effect in the vicinity of the critical point of CO2. Although Raman spectra of solutions of CO2 dissolved in D2O at 10 MPa and temperatures near the critical point of CO2 had adequate signal-to-noise and spatial resolution to observe a Soret effect with a Soret coefficient with magnitude of |ST| > 0.03, no evidence for an effect of this size was obtained for applied temperature gradients up to 19oC. The presence of 1 M NaCl did not make a difference. In contrast, the concentration of CO2 dissolved in H2O was shown to vary significantly across the temperature gradient when excess CO2 was present, but the results could be explained simply by the variation in CO2 solubility over the temperature range and not to kinetic factors. For mixtures of D2O dissolved in scCO2 at 10 MPa and temperatures close to the critical point of CO2, the Raman peaks for H2O were too weak to measure with confidence even at the limit of D2O solubility.

  19. Highly compacted biodegradable DNA nanoparticles capable of overcoming the mucus barrier for inhaled lung gene therapy.

    Science.gov (United States)

    Mastorakos, Panagiotis; da Silva, Adriana L; Chisholm, Jane; Song, Eric; Choi, Won Kyu; Boyle, Michael P; Morales, Marcelo M; Hanes, Justin; Suk, Jung Soo

    2015-07-14

    Gene therapy has emerged as an alternative for the treatment of diseases refractory to conventional therapeutics. Synthetic nanoparticle-based gene delivery systems offer highly tunable platforms for the delivery of therapeutic genes. However, the inability to achieve sustained, high-level transgene expression in vivo presents a significant hurdle. The respiratory system, although readily accessible, remains a challenging target, as effective gene therapy mandates colloidal stability in physiological fluids and the ability to overcome biological barriers found in the lung. We formulated highly stable DNA nanoparticles based on state-of-the-art biodegradable polymers, poly(β-amino esters) (PBAEs), possessing a dense corona of polyethylene glycol. We found that these nanoparticles efficiently penetrated the nanoporous and highly adhesive human mucus gel layer that constitutes a primary barrier to reaching the underlying epithelium. We also discovered that these PBAE-based mucus-penetrating DNA nanoparticles (PBAE-MPPs) provided uniform and high-level transgene expression throughout the mouse lungs, superior to several gold standard gene delivery systems. PBAE-MPPs achieved robust transgene expression over at least 4 mo following a single administration, and their transfection efficiency was not attenuated by repeated administrations, underscoring their clinical relevance. Importantly, PBAE-MPPs demonstrated a favorable safety profile with no signs of toxicity following intratracheal administration.

  20. High brightness MEMS mirror based head-up display (HUD) modules with wireless data streaming capability

    Science.gov (United States)

    Milanovic, Veljko; Kasturi, Abhishek; Hachtel, Volker

    2015-02-01

    A high brightness Head-Up Display (HUD) module was demonstrated with a fast, dual-axis MEMS mirror that displays vector images and text, utilizing its ~8kHz bandwidth on both axes. Two methodologies were evaluated: in one, the mirror steers a laser at wide angles of phone applications is demonstrated, utilizing the mobile device both for content generation based on various messages or data, and for content streaming to the MEMS controller via Bluetooth interface. The display unit is highly resistant to vibrations and shock, and requires only ~1.5W to operate, even with content readable in sunlit outdoor conditions. The low power requirement is in part due to a vector graphics approach, allowing the efficient use of laser power, and also due to the use of a single, relatively high efficiency laser and simple optics.

  1. Isolation rooms for highly infectious diseases: an inventory of capabilities in European countries

    DEFF Research Database (Denmark)

    Fusco, F M; Puro, V; Baka, A

    2009-01-01

    member states, performed an inventory of high level isolation rooms (HIRs, hospital rooms with negative pressure and anteroom). In participating countries, HIRs are available in at least 211 hospitals, with at least 1789 hospital beds. The adequacy of this number is not known and will depend......Isolation of patients with highly infectious diseases (HIDs) in hospital rooms with adequate technical facilities is essential to reduce the risk of spreading disease. The European Network for Infectious Diseases (EUNID), a project co-funded by European Commission and involving 16 European Union...

  2. High rate capability pure Sn-based nano-architectured electrode assembly for rechargeable lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bazin, L.; Mitra, S.; Taberna, P.L.; Gressier, M.; Menu, M.J.; Barnabe, A.; Simon, P. [CIRIMAT-UMR 5085- Universite Paul Sabatier, route de Narbonne, 31062 Toulouse Cedex 4 (France); Poizot, P.; Tarascon, J.-M. [LRCS-UMR 6007-Universite de Picardie Jules Verne, 33 rue Saint-Leu, 80039 Amiens (France)

    2009-03-15

    New high surface area nano-architectured copper current collectors have been designed based on simple electrodeposition method. The nano-architectured electrode design not only increases the effective surface area of the electrode but it is also very suitable for sustaining the mechanical and structural strain during electrochemical reaction. In this work, a nano-architectured Sn anode for Li-ion battery, based on Li-Sn alloying reaction, delivers very high cycle life and good power performance compared to planar tin films. This electrode could be successfully used in the field of 3D microbatteries. (author)

  3. Spatially offset Raman spectroscopy (SORS) for liquid screening

    Science.gov (United States)

    Loeffen, Paul W.; Maskall, Guy; Bonthron, Stuart; Bloomfield, Matthew; Tombling, Craig; Matousek, Pavel

    2011-11-01

    Recently, Spatially Offset Raman Spectroscopy (SORS) has been discussed as a novel method for the screening of liquids, aerosols and gels (LAGs) at airports and for other security applications. SORS is an optical spectroscopic method which enables the precise chemical identification of substances from a reference list and, due to the rich spectral information, has an inherently high probability of detection and low false alarm rate. The method is generally capable of screening substances inside non-metallic containers such as plastic and glass bottles. SORS is typically successful through opaque plastic and coloured glass, which are often challenging for conventional backscatter Raman spectroscopy. SORS is performed in just a few seconds by shining a laser light onto the container and then measuring the Raman signal at the excitation point but also at one or more offset positions. Each measurement has different relative orthogonal contributions from the container and contents Raman spectra, so that, with no prior knowledge, the pure Raman spectra of both the container and contents can be extracted - either by scaled subtraction or via multivariate statistical methods in an automated process. In this paper, the latest results will be described from a prototype SORS device designed for aviation security and the advantages and limitations of SORS will be discussed.

  4. Biophysical basis for noninvasive skin cancer detection using Raman spectroscopy

    Science.gov (United States)

    Feng, Xu; Moy, Austin J.; Markey, Mia K.; Fox, Matthew C.; Reichenberg, Jason S.; Tunnell, James W.

    2016-03-01

    Raman spectroscopy (RS) is proving to be a valuable tool for real time noninvasive skin cancer detection via optical fiber probe. However, current methods utilizing RS for skin cancer diagnosis rely on statistically based algorithms to provide tissue classification and do not elucidate the underlying biophysical changes of skin tissue. Therefore, we aim to use RS to explore skin biochemical and structural characteristics and then correlate the Raman spectrum of skin tissue with its disease state. We have built a custom confocal micro-Raman spectrometer system with an 830nm laser light. The high resolution capability of the system allows us to measure spectroscopic features from individual tissue components in situ. Raman images were collected from human skin samples from Mohs surgical biopsy, which were then compared with confocal laser scanning, two-photon fluorescence and hematoxylin and eosin-stained images to develop a linear model of skin tissue Raman spectra. In this model, macroscopic tissue spectra obtained from RS fiber probe were fit into a linear combination of individual basis spectra of primary skin constituents. The fit coefficient of the model explains the biophysical changes spanning a range of normal and various disease states. The model allows for determining parameters similar to that a pathologist is familiar reading and will be a significant guidance in developing RS diagnostic decision schemes.

  5. Biofilm-Forming Capability of Highly Virulent, Multidrug-Resistant Candida auris

    Science.gov (United States)

    Sherry, Leighann; Ramage, Gordon; Kean, Ryan; Borman, Andrew; Johnson, Elizabeth M.; Richardson, Malcolm D.

    2017-01-01

    The emerging multidrug-resistant yeast pathogen Candida auris has attracted considerable attention as a source of healthcare–associated infections. We report that this highly virulent yeast has the capacity to form antifungal resistant biofilms sensitive to the disinfectant chlorhexidine in vitro. PMID:28098553

  6. Capabilities for managing high-volume production of electric engineering equipment at the Electrochemical Production Plant

    Energy Technology Data Exchange (ETDEWEB)

    Podlednev, V.M.

    1996-04-01

    The Electromechanical Production Plant is essentially a research center with experimental facilities and power full testing base. Major products of the plant today include heat pipes and devices of their basis of different functions and power from high temperature ranges to cryogenics. This report describes work on porous titanium and carbon-graphite current collectors, electrocatalyst synthesis, and electrocatalyst applications.

  7. Multi-wire proportional chambers with a central hole and high counting-rate capability

    NARCIS (Netherlands)

    Volkerts, M; Bakker, A; Kalantar-Nayestanaki, N; Fraiquin, H; Eads, A; Rinckel, T; Solberg, K

    1999-01-01

    A set of two multi-wire proportional chambers with a central hole has been designed and built in a KVI-IUCF collaboration. These chambers, used for detecting charged particles with atomic masses up to A = 4 and energies up to 200 MeV, are highly efficient with efficiencies of 97-98% per plane at a c

  8. Investigating the Capability of High Resolution ALSM to Provide Accurate Watershed Delineation and Stream Network Data

    Science.gov (United States)

    Sedighi, A.; Slatton, K. C.; Hatfield, K.

    2007-05-01

    The development of geographic information systems (GIS) and digital elevation models (DEMs) has provided an opportunity to describe the pathways of water movement in a watershed. Adequate DEM resolution is of high importance in stream network detection. Local, state, and federal agencies have relied on US Geological Survey 1:24,000 scale topographic maps for information on stream networks for planning, management, and regulatory programs related to streams. DEM creation techniques that avoid map contours as the source of digital heights can improve watershed delineation and stream network data quality. Airborne Laser Swath Mapping (ALSM) technology (also referred to as LIDAR) provides DEMs of fine resolution and high accuracy. However, there are shortcomings in using both low resolution and high resolution DEMs. The focus of this work will be in the unique aspects of using ALSM data in watershed delineation and stream network mapping, in comparison to the other sources of DEM. In particular the reliability of both input data and output results of stream network using different resolutions will be evaluated. In this study, stream location resulting from high-resolution ALSM and low- resolution NED are compared to ground truth locations of the stream in Hogtown Creek Watershed, located in Gainesville, Florida. This study shows that ALSM-derived models are more successful at delineating streams and at locating them in their topographically correct position as compared to lower resolution DEMs. However, high resolution ALSM data produce artifacts that can affect the flow of water as predicted by stream network algorithms. Methods for overcoming the challenges with regard to ALSM data in stream network detection are presented.

  9. Novel Erythrocyte-like Graphene Microspheres with High Quality and Mass Production Capability via Electrospray Assisted Self-Assembly

    Science.gov (United States)

    Tian, Yayang; Wu, Guan; Tian, Xike; Tao, Xiaoming; Chen, Wei

    2013-11-01

    We report for the first time a novel erythrocyte-like graphene microsphere (ELGMs) which can be produced with high quality and mass production capability via electrospray assisted self-assembly. Through simple electrospray treatment of GO suspension into coagulation bath followed by chemical reduction, large quantity of ELGMs with uniform morphology and size can be obtained with production rate of around 2.4 mg/h. Compared with other 3D structures, the ELGMs have a very interesting structural characteristic of perfect exterior doughnut shape and interior porous network. Accordingly, the as-prepared porous ELGMs exhibit excellent capability for fast and recyclable removal of oil and toxic organic solvents from water, reaching up to 216 times of its weight in absorption efficiency, which is tens of times higher than that of conventional sorbent materials. It is strongly believed that the novel hierarchical graphene structures and synergy among different techniques will lead to more future advances in graphene applications.

  10. The Capabilities of Electrodischarge Microdrilling of High Aspect Ratio Holes in Ceramic Materials

    Directory of Open Access Journals (Sweden)

    Skoczypiec Sebastian

    2015-09-01

    Full Text Available In the first part of the article the review of ceramic materials drilling possibilities was presented. Among the described methods special attention is paid to electrodischarge drilling. This process have especially been predicted for machining difficult-to-cut electrically conductive materials. The second part consist of the results analysis of electrodischarge microdrilling of siliconized silicon carbide. The experiment involves the impact of current amplitude, discharge voltage and pulse time on the hole depth, side gap, linear tool wear and mean drilling speed. The results shows that electrodischarge drilling is a good alternative when machining inhomogeneous ceramic materials and gives possibility to drill high aspect ratio holes with relatively high efficiency (the drilling speed >2 mm/min.

  11. Numerical simulations on efficiency and measurement of capabilities of BGO detectors for high energy gamma ray

    CERN Document Server

    Wen Wan Xin

    2002-01-01

    The energy resolution and time resolution of two phi 75 x 100 BGO detectors for high energy gamma ray newly made were measured with sup 1 sup 3 sup 7 Cs and sup 6 sup 0 Co resources. The two characteristic gamma rays of high energy emitted from the thermal neutron capture of germanium in BGO crystal were used for the energy calibration of gamma spectra. The intrinsic photopeak efficiency, single escape probability and double escape probabilities of BGO detectors in photon energy range of 4-30 MeV are numerically calculated with GEANT code. The real count response and count ratio of the uniformly distributed incident photons in energy range of 0-30 MeV are also calculated. The distortion of gamma spectra caused by the photon energy loss extension to lower energy in detection medium is discussed

  12. Motion Control of a Four-wheel-drive Omnidirectional Wheelchair with High Step Climbing Capability

    OpenAIRE

    WADA, Masayoshi

    2010-01-01

    Mechanism and omnidirectional control of a 4WD mechanism for wheelchairs are presented in this chapter. The omnidirectional wheelchair system is proposed for improving maneuverability of standard wheelchairs The 4WD mechanism has high mobility which equips four wheels, two omni-wheels in the front and two normal tires in the rear, and all wheels provide traction even with two motors to drive these wheels. To realize holonomic and omnidirectional motion of a chair by utilizing the 4WD mechanis...

  13. Adaptation and acclimatization to formaldehyde in methylotrophs capable of high-concentration formaldehyde detoxification.

    Science.gov (United States)

    Chongcharoen, Rotsaman; Smith, Thomas J; Flint, Kenneth P; Dalton, Howard

    2005-08-01

    Formaldehyde is a highly toxic chemical common in industrial effluents, and it is also an intermediate in bacterial metabolism of one-carbon growth substrates, although its role as a bacterial growth substrate per se has not been extensively reported. This study investigated two highly formaldehyde-resistant formaldehyde utilizers, strains BIP and ROS1; the former strain has been used for industrial remediation of formaldehyde-containing effluents. The two strains were shown by means of 16S rRNA characterization to be closely related members of the genus Methylobacterium. Both strains were able to use formaldehyde, methanol and a range of multicarbon compounds as their principal growth substrate. Growth on formaldehyde was possible up to a concentration of at least 58 mM, and survival at up to 100 mM was possible after stepwise acclimatization by growth at increasing concentrations of formaldehyde. At such high concentrations of formaldehyde, the cultures underwent a period of formaldehyde removal without growth before the formaldehyde concentration fell below 60 mM, and growth could resume. Two-dimensional electrophoresis and MS characterization of formaldehyde-induced proteins in strain BIP revealed that the pathways of formaldehyde metabolism, and adaptations to methylotrophic growth, were very similar to those seen in the well-characterized methanol-utilizing methylotroph Methylobacterium extorquens AM1. Thus, it appears that many of the changes in protein expression that allow strain BIP to grow using high formaldehyde concentrations are associated with expression of the same enzymes used by M. extorquens AM1 to process formaldehyde as a metabolic intermediate during growth on methanol.

  14. High product variety and company performance - organization and configuration of strategic capabilities

    OpenAIRE

    Wellige, Moritz

    2015-01-01

    Today, business environments are oftentimes characterized by ever-changing market conditions. Major drivers of these changes are increasingly heterogeneous customer needs due in particular to regionally differing requirements, continuously rising demand for new product functionalities and features, and shortening product life cycles and time-to-market periods. Mass customization – more generally referred to as high-variety product strategies – are seen as promising strategic orientations for ...

  15. Next generation fuel irradiation capability in the High Flux Reactor Petten

    Energy Technology Data Exchange (ETDEWEB)

    Fuetterer, Michael A., E-mail: michael.fuetterer@jrc.n [European Commission, Joint Research Centre, Institute for Energy (JRC-IE), P.O. Box 2, NL-1755 ZG Petten (Netherlands); D' Agata, Elio; Laurie, Mathias; Marmier, Alain; Scaffidi-Argentina, Francesco [European Commission, Joint Research Centre, Institute for Energy (JRC-IE), P.O. Box 2, NL-1755 ZG Petten (Netherlands); Raison, Philippe [European Commission, Joint Research Centre, Institute for Transuranium Elements (JRC-ITU), D-76334 Eggenstein-Leopoldshafen (Germany); Bakker, Klaas; Groot, Sander de; Klaassen, Frodo [Nuclear Research and consultancy Group (NRG), P.O. Box 25, NL-1755 ZG Petten (Netherlands)

    2009-07-15

    This paper describes selected equipment and expertise on fuel irradiation testing at the High Flux Reactor (HFR) in Petten, The Netherlands. The reactor went critical in 1961 and holds an operating license up to at least 2015. While HFR has initially focused on Light Water Reactor fuel and materials, it also played a decisive role since the 1970s in the German High Temperature Reactor (HTR) development program. A variety of tests related to fast reactor development in Europe were carried out for next generation fuel and materials, in particular for Very High Temperature Reactor (V/HTR) fuel, fuel for closed fuel cycles (U-Pu and Th-U fuel cycle) and transmutation, as well as for other innovative fuel types. The HFR constitutes a significant European infrastructure tool for the development of next generation reactors. Experimental facilities addressed include V/HTR fuel tests, a coated particle irradiation rig, and tests on fast reactor, transmutation and thorium fuel. The rationales for these tests are given, results are provided and further work is outlined.

  16. A Stimulated Raman Scattering CMOS Pixel Using a High-Speed Charge Modulator and Lock-in Amplifier

    Directory of Open Access Journals (Sweden)

    De Xing Lioe

    2016-04-01

    Full Text Available A complementary metal-oxide semiconductor (CMOS lock-in pixel to observe stimulated Raman scattering (SRS using a high speed lateral electric field modulator (LEFM for photo-generated charges and in-pixel readout circuits is presented. An effective SRS signal generated after the SRS process is very small and needs to be extracted from an extremely large offset due to a probing laser signal. In order to suppress the offset components while amplifying high-frequency modulated small SRS signal components, the lock-in pixel uses a high-speed LEFM for demodulating the SRS signal, resistor-capacitor low-pass filter (RC-LPF and switched-capacitor (SC integrator with a fully CMOS differential amplifier. AC (modulated components remained in the RC-LPF outputs are eliminated by the phase-adjusted sampling with the SC integrator and the demodulated DC (unmodulated components due to the SRS signal are integrated over many samples in the SC integrator. In order to suppress further the residual offset and the low frequency noise (1/f noise components, a double modulation technique is introduced in the SRS signal measurements, where the phase of high-frequency modulated laser beam before irradiation of a specimen is modulated at an intermediate frequency and the demodulation is done at the lock-in pixel output. A prototype chip for characterizing the SRS lock-in pixel is implemented and a successful operation is demonstrated. The reduction effects of residual offset and 1/f noise components are confirmed by the measurements. A ratio of the detected small SRS to offset a signal of less than 10−5 is experimentally demonstrated, and the SRS spectrum of a Benzonitrile sample is successfully observed.

  17. A Stimulated Raman Scattering CMOS Pixel Using a High-Speed Charge Modulator and Lock-in Amplifier.

    Science.gov (United States)

    Lioe, De Xing; Mars, Kamel; Kawahito, Shoji; Yasutomi, Keita; Kagawa, Keiichiro; Yamada, Takahiro; Hashimoto, Mamoru

    2016-04-13

    A complementary metal-oxide semiconductor (CMOS) lock-in pixel to observe stimulated Raman scattering (SRS) using a high speed lateral electric field modulator (LEFM) for photo-generated charges and in-pixel readout circuits is presented. An effective SRS signal generated after the SRS process is very small and needs to be extracted from an extremely large offset due to a probing laser signal. In order to suppress the offset components while amplifying high-frequency modulated small SRS signal components, the lock-in pixel uses a high-speed LEFM for demodulating the SRS signal, resistor-capacitor low-pass filter (RC-LPF) and switched-capacitor (SC) integrator with a fully CMOS differential amplifier. AC (modulated) components remained in the RC-LPF outputs are eliminated by the phase-adjusted sampling with the SC integrator and the demodulated DC (unmodulated) components due to the SRS signal are integrated over many samples in the SC integrator. In order to suppress further the residual offset and the low frequency noise (1/f noise) components, a double modulation technique is introduced in the SRS signal measurements, where the phase of high-frequency modulated laser beam before irradiation of a specimen is modulated at an intermediate frequency and the demodulation is done at the lock-in pixel output. A prototype chip for characterizing the SRS lock-in pixel is implemented and a successful operation is demonstrated. The reduction effects of residual offset and 1/f noise components are confirmed by the measurements. A ratio of the detected small SRS to offset a signal of less than 10(-)⁵ is experimentally demonstrated, and the SRS spectrum of a Benzonitrile sample is successfully observed.

  18. Highly Sensitive Detection of Clenbuterol in Animal Urine Using Immunomagnetic Bead Treatment and Surface-Enhanced Raman Spectroscopy

    Science.gov (United States)

    Cheng, Jie; Su, Xiao-Ou; Wang, Shi; Zhao, Yiping

    2016-09-01

    Combining surface-enhanced Raman spectroscopy (SERS) of aggregated graphene oxide/gold nanoparticle hybrids with immunomagnetic bead sample preparation method, a highly sensitive strategy to determine the clenbuterol content in animal urine was developed. Based on a linear calibration curve of the SERS characteristic peak intensity of clenbuterol at Δv = 1474 cm-1 versus the spiked clenbuterol concentration in the range of 0.5-20 ng·mL-1, the quantity of clenbuterol in real animal urine samples can be determined and matches well with those determined by LC-MS/MS, while the detection time is significantly reduced to 15 min/sample. The limits of detection and quantification in the urine are 0.5 ng·mL-1 and 1 ng·mL-1, respectively, and the recovery clenbuterol rates are 82.8-92.4% with coefficients of variation life of the SERS substrates is no less than 4 weeks. All these indicate that this proposed SERS detection protocol for clenbuterol is reproducible, reliable, and can be easily developed for the routine monitoring of the illicit use of clenbuterol in animal farming.

  19. Structural model of homogeneous As–S glasses derived from Raman spectroscopy and high-resolution XPS

    Energy Technology Data Exchange (ETDEWEB)

    Golovchak, R.; Shpotyuk, O.; Mccloy, J. S.; Riley, B. J.; Windisch, C. F.; Sundaram, S. K.; Kovalskiy, A.; Jain, H.

    2010-11-28

    The structure of homogeneous bulk As x S100- x (25 ≤ x ≤ 42) glasses, prepared by the conventional rocking–melting–quenching method, was investigated using high-resolution X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. It is shown that the main building blocks of their glass networks are regular AsS3/2 pyramids and sulfur chains. In the S-rich domain, the existence of quasi-tetrahedral (QT) S = As(S1/2)3 units is deduced from XPS data, but with a concentration not exceeding ~3–5% of total atomic sites. Therefore, QT units do not appear as primary building blocks of the glass backbone in these materials, and an optimally-constrained network may not be an appropriate description for glasses when x < 40. Finally, it is shown that, in contrast to Se-based glasses, the ‘chain-crossing’ model is only partially applicable to sulfide glasses.

  20. STARR: shortwave-targeted agile Raman robot for the detection and identification of emplaced explosives

    Science.gov (United States)

    Gomer, Nathaniel R.; Gardner, Charles W.

    2014-05-01

    In order to combat the threat of emplaced explosives (land mines, etc.), ChemImage Sensor Systems (CISS) has developed a multi-sensor, robot mounted sensor capable of identification and confirmation of potential threats. The system, known as STARR (Shortwave-infrared Targeted Agile Raman Robot), utilizes shortwave infrared spectroscopy for the identification of potential threats, combined with a visible short-range standoff Raman hyperspectral imaging (HSI) system for material confirmation. The entire system is mounted onto a Talon UGV (Unmanned Ground Vehicle), giving the sensor an increased area search rate and reducing the risk of injury to the operator. The Raman HSI system utilizes a fiber array spectral translator (FAST) for the acquisition of high quality Raman chemical images, allowing for increased sensitivity and improved specificity. An overview of the design and operation of the system will be presented, along with initial detection results of the fusion sensor.

  1. High frequency modulation capabilities and quasi single-sideband emission from a quantum cascade laser.

    Science.gov (United States)

    Hangauer, Andreas; Spinner, Georg; Nikodem, Michal; Wysocki, Gerard

    2014-09-22

    Both intensity- (IM) and frequency-modulation (FM) behavior of a directly modulated quantum cascade laser (QCL) are measured from 300 Hz to 1.7 GHz. Quantitative measurements of tuning coefficients has been performed and the transition from thermal- to electronic-tuning is clearly observed. A very specific FM behavior of QCLs has been identified which allows for optical quasi single sideband (SSB) modulation through current injection and has not been observed in directly modulated semiconductor lasers before. This predestines QCLs in applications where SSB is required, such as telecommunication or high speed spectroscopy. The experimental procedure and theoretical modeling for data extraction is discussed.

  2. A High-Resolution Capability for Large-Eddy Simulation of Jet Flows

    Science.gov (United States)

    DeBonis, James R.

    2011-01-01

    A large-eddy simulation (LES) code that utilizes high-resolution numerical schemes is described and applied to a compressible jet flow. The code is written in a general manner such that the accuracy/resolution of the simulation can be selected by the user. Time discretization is performed using a family of low-dispersion Runge-Kutta schemes, selectable from first- to fourth-order. Spatial discretization is performed using central differencing schemes. Both standard schemes, second- to twelfth-order (3 to 13 point stencils) and Dispersion Relation Preserving schemes from 7 to 13 point stencils are available. The code is written in Fortran 90 and uses hybrid MPI/OpenMP parallelization. The code is applied to the simulation of a Mach 0.9 jet flow. Four-stage third-order Runge-Kutta time stepping and the 13 point DRP spatial discretization scheme of Bogey and Bailly are used. The high resolution numerics used allows for the use of relatively sparse grids. Three levels of grid resolution are examined, 3.5, 6.5, and 9.2 million points. Mean flow, first-order turbulent statistics and turbulent spectra are reported. Good agreement with experimental data for mean flow and first-order turbulent statistics is shown.

  3. A high resolution, monolithic crystal, PET/MRI detector with DOI positioning capability.

    Science.gov (United States)

    Li, Xiaoli; Lockhart, Cate; Lewellen, Tom K; Miyaoka, Robert S

    2008-01-01

    We report on a high resolution, monolithic crystal PET detector design that provides depth of interaction (DOI) positioning within the crystal and is compatible for operation in a MRI scanner to support multimodal anatomic and functional imaging. Our design utilizes a novel sensor on the entrance surface (SES) design combined with a maximum likelihood positioning algorithm. The sensor will be a two-dimensional array of micro-pixel avalanche photodiodes (MAPD). MAPDs are a new type of solid-state photodetector with Geiger mode operation that can provide signal gain similar to a photomltipiler tube (PMT). In addition, they can be operated in high magnetic fields to support PET/MR imaging. Utilizing a multi-step simulation process, we determined the intrinsic spatial resolution characteristics of a detector using the proposed design. For a 48.8 mm by 48.8 mm by 15 mm LSO crystal detector readout by an 8 by 8 array of 5.8 mm by 5.8 mm MAPD elements the intrinsic spatial resolution is 0.83 mm FWHM in X, 0.92 mm FWHM in Y and 1.83 mm FWHM in Z (i.e., DOI) for normally incident photons. Comparing the results versus using a conventional design with the photosensors on the backside of the crystal, an average improvement of 25% in X, 23% in Y, and 20% in Z is achieved.

  4. New experimental capabilities and theoretical insights of high pressure compression waves

    Energy Technology Data Exchange (ETDEWEB)

    Orlikowski, D; Nguyen, J; Patterson, J R; Minich, R; Martin, L P; Holmes, N

    2007-07-20

    Currently there are three platforms that offer quasi-isentropic compression or ramp-wave compression (RWC): light-gas gun, magnetic flux (Z-pinch), and laser. We focus here on the light-gas gun technique and on some current theoretical insights from experimental data. A gradient impedance through the length of the impactor provides the pressure pulse upon impactor to the subject material. Applications and results are given concerning high-pressure strength and liquid to solid, phase transition of water plus its associated phase fraction history. We also introduce the Korteweg-deVries-Burgers equation as a means to understand the evolution these RWC waves that propagate through the thickness of the subject material. This equation has the necessary competition between non-linear, dispersion, and dissipation processes, which is shown through observed structures that are manifested in the experimental particle velocity histories. Such methodology points towards a possible quantifiable dissipation, through which RWC experiments may be analyzed.

  5. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological

  6. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological theor

  7. Capability ethics

    NARCIS (Netherlands)

    I.A.M. Robeyns (Ingrid)

    2012-01-01

    textabstractThe capability approach is one of the most recent additions to the landscape of normative theories in ethics and political philosophy. Yet in its present stage of development, the capability approach is not a full-blown normative theory, in contrast to utilitarianism, deontological theor

  8. Instant detection and identification of concealed explosive-related compounds: Induced Stokes Raman versus infrared.

    Science.gov (United States)

    Elbasuney, Sherif; El-Sherif, Ashraf F

    2017-01-01

    The instant detection of explosives and explosive-related compounds has become an urgent priority in recent years for homeland security and counter-terrorism applications. Modern techniques should offer enhancement in selectivity, sensitivity, and standoff distances. Miniaturisation, portability, and field-ruggedisation are crucial requirements. This study reports on instant and standoff identification of concealed explosive-related compounds using customized Raman technique. Stokes Raman spectra of common explosive-related compounds were generated and spectrally resolved to create characteristic finger print spectra. The scattered Raman emissions over the band 400:2000cm(-1) were compared to infrared absorption using FTIR. It has been demonstrated that the two vibrational spectroscopic techniques were opposite and completing each other. Molecular vibrations with strong absorption in infrared (those involve strong change in dipole moments) induced weak signals in Raman and vice versa. The tailored Raman offered instant detection, high sensitivity, and standoff detection capabilities. Raman demonstrated characteristic fingerprint spectra with stable baseline and sharp intense peaks. Complete correlations of absorption/scattered signals to certain molecular vibrations were conducted to generate an entire spectroscopic profile of explosive-related compounds. This manuscript shades the light on Raman as one of the prevailing technologies for instantaneous detection of explosive-related compounds. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  9. Design of a High Resolution, Monolithic Crystal, PET/MRI Detector with DOI Positioning Capability.

    Science.gov (United States)

    Miyaoka, Robert S; Li, Xiaoli; Lockhart, Cate; Lewellen, Tom K

    2008-10-01

    We report on a high resolution, monolithic crystal PET detector design concept that provides depth of interaction (DOI) positioning within the crystal and is compatible for operation in a MRI scanner to support multimodal anatomic and functional imaging. Our design utilizes a novel sensor on the entrance surface (SES) approach combined with a maximum likelihood positioning algorithm. The sensor will be a two-dimensional array of micro-pixel avalanche photodiodes (MAPD). MAPDs are a new type of solid-state photodetector with Geiger mode operation that can provide signal gain similar to a photomltipiler tube (PMT). In addition, they can be operated in high magnetic fields to support PET/MR imaging. Utilizing a multi-step simulation process, we determined the intrinsic spatial resolution characteristics for a variety of detector configurations. The crystal was always modeled as a 48.8 mm by 48.8 mm by 15 mm monolithic slab of a lutetium-based scintillator. The SES design was evaluated via simulation for three different two-dimensional MAPD array sizes: 8×8 with 5.8×5.8 mm(2) pads; 12×12 with 3.8×3.8 mm(2) pads; and 16×16 with 2.8×2.8 mm(2) pads. To reduce the number of signal channels row-column summing readout was explored for the 12×12 and 16×16 channel array devices. The intrinsic spatial resolution for the 8×8 MAPD array is 0.88 mm FWHM in X and Y, and 1.83 mm FWHM in Z (i.e., DOI). Comparing the results versus using a conventional design with the photosensors on the backside of the crystal, an average improvement of ~24% in X and Y and 20% in Z is achieved. The X, Y intrinsic spatial resolution improved to 0.66 mm and 0.65 mm FWHM for the 12×12 and 16×16 MAPDs using row-column readout. Using the 12×12 and 16×16 arrays also led to a slight improvement in the DOI positioning accuracy.

  10. A Novel Scanning Near-Field Microwave Microscope Capable of High Resolution Loss Imaging

    Science.gov (United States)

    Imtiaz, Atif

    2005-03-01

    To study novel physics in condensed matter and materials science, experimental techniques need to be pushed for better sensitivity and higher spatial resolution. Classical techniques of probing the high frequency electrical properties of materials are limited in resolution to the wavelength of the incident electromagnetic wave. We report here a novel near-field microwave microscope to image materials contrast, with 2.5 nm spatial resolution in capacitance. Our objective is to improve the spatial resolution in local loss imaging. We will present evidence of sheet resistance contrast in a Boron-doped Silicon sample on sub- micron length scales. We will present quantitative analysis of the data on the Boron-doped Silicon sample in light of evanescent wave model of the microscope that we have developed. In addition, the probe to sample interaction on nanometer length scales will be discussed [1]. This work has been supported by an NSF IMR Grant DMR-9802756, and the University of Maryland/Rutgers NSF-MRSEC through the Near Field Microwave Microscope Shared Experimental Facility Grant DMR-00-80008. [1] Atif Imtiaz, Marc Pollak, Steven M. Anlage, John D. Barry and John Melngailis, ``Near-Field Microwave Microscopy on nanometer length scales'', to be published in J. Appl. Phys. (Feb. 1, 2005).

  11. Two-particle response in cluster dynamical mean-field theory: formalism and application to the Raman response of high-temperature superconductors.

    Science.gov (United States)

    Lin, Nan; Gull, Emanuel; Millis, Andrew J

    2012-09-07

    A method is presented for the unbiased numerical computation of two-particle response functions of correlated electron materials via a solution of the dynamical mean-field equations in the presence of a perturbing field. The power of the method is demonstrated via a computation of the Raman B(1g) and B(2g) scattering intensities of the two-dimensional Hubbard model in parameter regimes believed to be relevant to high-temperature superconductivity. The theory reproduces the "two-magnon" peak characteristic of the Raman intensity of insulating parent compounds of high-T(c) copper oxide superconductors, and shows how it evolves to a quasiparticle response, as carriers are added. The method can be applied in any situation where a solution of equilibrium dynamical mean-field equations is feasible.

  12. Raman spectra of ethane adn ethylene adsorbed of surface of catalyst Sm 2 O 3/MgO at high temperatures

    Science.gov (United States)

    Bobrov, A. V.; Plate, S. E.; Kadushin, A. A.; Kimel'feld, Ya. M.; Seleznev, V. A.; Tulenin, Yu. P.

    1992-03-01

    Raman spectroscopy has been applied for the investigation in situ of catalytic transformations of ethane ethylene and deuterated ethylene on the surface of catalyst Sm 2O 3/MgO at high temperatures (up to 980 K). Ethane and ethylene are the products of the oxidation dehydration of methane. For the understanding of mechanism of this process it is interesting to study of the spectra of ethane and ethylene in the conditions of the real process at high temperature. In the previous paper [1] we have shown that during the flowring of mixture methane with oxygen through the catalyst Sm 2O 3/MgO methane dissociates on CH 3 and CH 2 groups. It has been confirmed by experiment with deuterated methane. The purpose of this work is to study the interaction of ethane and ethylene with Sm 2O 3/MgO in similar conditions by Raman spectroscopy.

  13. Femtosecond time-resolved optical and Raman spectroscopy of photoinduced spin crossover: temporal resolution of low-to-high spin optical switching.

    Science.gov (United States)

    Smeigh, Amanda L; Creelman, Mark; Mathies, Richard A; McCusker, James K

    2008-10-29

    A combination of femtosecond electronic absorption and stimulated Raman spectroscopies has been employed to determine the kinetics associated with low-spin to high-spin conversion following charge-transfer excitation of a FeII spin-crossover system in solution. A time constant of tau = 190 +/- 50 fs for the formation of the 5T2 ligand-field state was assigned based on the establishment of two isosbestic points in the ultraviolet in conjunction with changes in ligand stretching frequencies and Raman scattering amplitudes; additional dynamics observed in both the electronic and vibrational spectra further indicate that vibrational relaxation in the high-spin state occurs with a time constant of ca. 10 ps. The results set an important precedent for extremely rapid, formally forbidden (DeltaS = 2) nonradiative relaxation as well as defining the time scale for intramolecular optical switching between two electronic states possessing vastly different spectroscopic, geometric, and magnetic properties.

  14. Capability of C-Band SAR for Operational Wetland Monitoring at High Latitudes

    Directory of Open Access Journals (Sweden)

    Julia Reschke

    2012-10-01

    Full Text Available Wetlands store large amounts of carbon, and depending on their status and type, they release specific amounts of methane gas to the atmosphere. The connection between wetland type and methane emission has been investigated in various studies and utilized in climate change monitoring and modelling. For improved estimation of methane emissions, land surface models require information such as the wetland fraction and its dynamics over large areas. Existing datasets of wetland dynamics present the total amount of wetland (fraction for each model grid cell, but do not discriminate the different wetland types like permanent lakes, periodically inundated areas or peatlands. Wetland types differently influence methane fluxes and thus their contribution to the total wetland fraction should be quantified. Especially wetlands of permafrost regions are expected to have a strong impact on future climate due to soil thawing. In this study ENIVSAT ASAR Wide Swath data was tested for operational monitoring of the distribution of areas with a long-term SW near 1 (hSW in northern Russia (SW = degree of saturation with water, 1 = saturated, which is a specific characteristic of peatlands. For the whole northern Russia, areas with hSW were delineated and discriminated from dynamic and open water bodies for the years 2007 and 2008. The area identified with this method amounts to approximately 300,000 km2 in northern Siberia in 2007. It overlaps with zones of high carbon storage. Comparison with a range of related datasets (static and dynamic showed that hSW represents not only peatlands but also temporary wetlands associated with post-forest fire conditions in permafrost regions. Annual long-term monitoring of change in boreal and tundra environments is possible with the presented approach. Sentinel-1, the successor of ENVISAT ASAR, will provide data that may allow continuous monitoring of these wetland dynamics in the future complementing global observations of

  15. A high-performance Raman-Ramsey Cs vapor cell atomic clock

    Science.gov (United States)

    Abdel Hafiz, Moustafa; Coget, Grégoire; Yun, Peter; Guérandel, Stéphane; de Clercq, Emeric; Boudot, Rodolphe

    2017-03-01

    We demonstrate a high-performance coherent-population-trapping (CPT) Cs vapor cell atomic clock using the push-pull optical pumping technique in the pulsed regime, allowing the detection of high-contrast and narrow Ramsey-CPT fringes. The impact of several experimental parameters onto the clock resonance and short-term fractional frequency stability, including the laser power, the cell temperature, and the Ramsey sequence parameters, has been investigated. We observe and explain the existence of a slight dependence on laser power of the central Ramsey-CPT fringe line-width in the pulsed regime. We report also that the central fringe line-width is commonly narrower than the expected Ramsey line-width given by 1 / ( 2 T R ) , with TR the free-evolution time, for short values of TR. The clock demonstrates a short-term fractional frequency stability at the level of 2.3 × 10 - 13 τ - 1 / 2 up to 100 s averaging time, mainly limited by the laser amplitude modulation noise. Comparable performances are obtained in the conventional continuous wave regime, with the use of an additional laser power stabilization setup. The pulsed interaction allows to reduce significantly the clock frequency sensitivity to laser power variations, especially for high values of TR. This pulsed CPT clock, ranking among the best microwave vapor cell atomic frequency standards, could find applications in telecommunication, instrumentation, defense or satellite-based navigation systems.

  16. Current and future capabilities of the neutron reflectometer MIRROR at Oak Ridge National Laboratory's High Flux Isotope Reactor

    Science.gov (United States)

    Hamilton, W. A.; Smith, G. S.; Taylor, G. B.; Larkins, B. M.; Porcar, L.

    2006-11-01

    The peripatetic ORNL HFIR Center for Neutron Scattering reflectometer instrument MIRROR has recently been re-installed in an interim beam line position in the reactor beam room. In 2006 an upgraded version of the instrument will move to a high intensity guide hall position fed by the new HFIR cold source. In this short note, we present some aspects of current instrument operation-particularly with respect to data reduction from the instrument's linear reflection plane detector-with examples of ongoing research and analysis, and a brief outline of the expected capabilities of the fully upgraded guide hall instrument.

  17. Investigation of Fast Timing Capabilities of Silicon Sensors for the CMS High Granularity Calorimeter at HL-LHC

    CERN Document Server

    Apresyan, Artur

    2016-01-01

    The High Granularity Calorimeter (HGCAL) is the technology choice of the CMS collaboration for the endcap calorimetry upgrade planned to cope with the harsh radiation and unprecedented in-time event pileup projected at the High Luminosity-LHC era. In this context, profiting from fast-timing information (~tens of picoseconds) embedded in the calorimeter would represent a unique capability for resolving information from individual collisions at the HL-LHC. This will enhance the reconstruction and physics capabilities of the CMS detector in terms of pileup mitigation and particle identification. The HGCAL is realized as a sampling calorimeter, including 40 layers of silicon pad detectors with pad areas of 0.5 â?? 1.0 cm^2 and three active thicknesses 320, 200 and 120 μm. Prototype p-in-n and n-in-p 5x5mm^2 silicon pads, with thicknesses of 285, 211 and 133μm, were tested with high-energy electrons at the CERN SPS. We present the motivation for this study including the concept and use of fast-timing in th...

  18. Analysis of stationary fuel cell dynamic ramping capabilities and ultra capacitor energy storage using high resolution demand data

    Science.gov (United States)

    Meacham, James R.; Jabbari, Faryar; Brouwer, Jacob; Mauzey, Josh L.; Samuelsen, G. Scott

    Current high temperature fuel cell (HTFC) systems used for stationary power applications (in the 200-300 kW size range) have very limited dynamic load following capability or are simply base load devices. Considering the economics of existing electric utility rate structures, there is little incentive to increase HTFC ramping capability beyond 1 kWs -1 (0.4% s -1). However, in order to ease concerns about grid instabilities from utility companies and increase market adoption, HTFC systems will have to increase their ramping abilities, and will likely have to incorporate electrical energy storage (EES). Because batteries have low power densities and limited lifetimes in highly cyclic applications, ultra capacitors may be the EES medium of choice. The current analyses show that, because ultra capacitors have a very low energy storage density, their integration with HTFC systems may not be feasible unless the fuel cell has a ramp rate approaching 10 kWs -1 (4% s -1) when using a worst-case design analysis. This requirement for fast dynamic load response characteristics can be reduced to 1 kWs -1 by utilizing high resolution demand data to properly size ultra capacitor systems and through demand management techniques that reduce load volatility.

  19. High-pressure Raman study of two ferroelectric crystals closely related to PbTiO3

    Science.gov (United States)

    Burns, Gerald; Sanjurjo, J. A.; López-Cruz, E.

    1984-12-01

    We report high-pressure Raman measurements of the zone-center phonons in two ferroelectric crystals that closely resemble the ABO3 perovskite crystal PbTiO3. These crystals are (Pb0.22Ba0.78)TiO3, i.e., Ba replacing Pb on the A site, and Pb(Ti0.81Sn0.19)O3, i.e., Sn replacing Ti on the B site. In both cases, at room temperature, we follow the modes and determine Pc, the transition pressure from the ferroelectric tetragonal phase to the cubic phase, to be 4.3 and 9.0 GPa, respectively. By observing the coalescence to the same frequency of the appropriate high-energy A1(TO)+E(TO) pairs of phonons, we determine the second-order character of the phase transitions at Pc. The tendency towards a second-order phase transition seems to be the rule at Pc as long as one makes the measurements at a temperature well below Tc; this is in agreement with theory. Thus, these systems exhibit tricritical points in the (P,T) phase diagram. The soft-E(TO)-phonon frequency (ω0) and damping constant (γ) can be measured to pressures reasonably close to Pc while the mode remains underdamped. These results are discussed in terms of a frequency-independent damping constant for the behavior of ω0 and γ near Pc. In the (Pb,Ba)TiO3 crystal, the hydrostatic pressure increases the intensity of the soft A1(TO) mode making it observable. This seems to happen in general in the perovskites. In the Pb(Ti,Sn)O3 crystal we observe the coupling of the soft E(TO) mode with an extra mode at 59 cm-1; this also has been studied as a function of temperature.

  20. Facile synthesis of nickel–cobalt double hydroxide nanosheets with high rate capability for application in supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Minmin; Xue, Junying; Zhang, Fangming; Ma, Wenle; Cui, Hongtao, E-mail: htcui@ytu.edu.cn [Yantai University, Shandong Provincial Engineering Research Center for Comprehensive Utilization of Light Hydrocarbons, College of Chemistry and Chemical Engineering (China)

    2015-02-15

    In this work, nickel–cobalt double hydroxide nanosheets with high rate capability are prepared by a facile epoxide precipitation route. The synthetic procedure includes an oxidization step using ammonium persulfate as oxidant and a precipitation step using propylene oxide as precipitation agent. As shown in the results of electrochemical characterization, high specific capacitance of 2548 F g{sup −1} for this material can be obtained at current density of 0.9 A g{sup −1} in aqueous solution of 3 mol L{sup −1 }KOH. It is surprising to notice that the capacitance of material still remains 1587 F g{sup −1} at high current density of 35.7 A g{sup −1}. These results demonstrate that the as-prepared nickel–cobalt double hydroxide nanosheets are promising electrode material for supercapacitor application as a primary power source.

  1. Enhancement of chemical sensing capability in a photonic crystal fiber with a hollow high index ring defect at the center.

    Science.gov (United States)

    Park, Jiyoung; Lee, Sejin; Kim, Soan; Oh, Kyunghwan

    2011-01-31

    A new type of index-guided photonic crystal fiber is proposed to enhance chemical sensing capability by introducing a hollow high index ring defect that consists of the central air hole surrounded by a high index GeO2 doped SiO2 glass ring. Optical properties of the fundamental guided mode were numerically analyzed using the full-vector finite element method varying the design parameters of both the defects in the center and the hexagonal air-silica lattice in the cladding. Enhanced evanescent wave interaction in the holey region and lower confinement loss by an order of magnitude were achieved simultaneously, which shows a high potential in hyper sensitive fiber-optic chemical sensing applications.

  2. Pulsed laser deposition of Ag nanoparticles on titanium hydroxide/oxide nanobelt arrays for highly sensitive surface-enhanced Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jing, Yuting; Wang, Huanwen; Zhao, Jie; Yi, Huan; Wang, Xuefeng, E-mail: xfwang@tongji.edu.cn

    2015-08-30

    Highlights: • Silver nanoparticles (NPs) were deposited on Ti(OH){sub 4} nanobelt by pulsed laser deposition (PLD). • The highest enhancement factor of 10{sup 6} and a maximum relative standard deviation (RSD) of 0.18. • Ag{sub 2}O play important role for the high sensitivity Raman phenomenon. • Charge transfer from Ag NPs is also responsible for the enhancement ability. - Abstract: Surface-enhanced Raman scattering (SERS) substrate of Ti(OH){sub 4} nanobelt arrays (NBAs) was synthesized by a hydrothermal reaction, on which silver nanoparticles (NPs) were deposited by pulsed laser deposition (PLD). Field-emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed the effective high specific surface area with silver NPs decorated on three-dimensional NBAs. Using rhodamine 6G (R6G) as an analyte molecule, the highest enhancement factor of 10{sup 6} and a maximum relative standard deviation (RSD) of 0.18 were obtained. It has been found that the specific morphology of these composite nanobelt arrays and the formation of Ag{sub 2}O play important role for the high sensitivity Raman phenomenon. In addition, the surface plasmon resonance wavelength of Ag decorated Ti(OH){sub 4} NBAs and the charge transfer from Ag NPs are also responsible for the enhancement ability. For comparison SERS was investigated with silver particles decorated on TiO{sub 2} NBAs, which is much less active.

  3. The DoD's High Performance Computing Modernization Program - Ensuing the National Earth Systems Prediction Capability Becomes Operational

    Science.gov (United States)

    Burnett, W.

    2016-12-01

    The Department of Defense's (DoD) High Performance Computing Modernization Program (HPCMP) provides high performance computing to address the most significant challenges in computational resources, software application support and nationwide research and engineering networks. Today, the HPCMP has a critical role in ensuring the National Earth System Prediction Capability (N-ESPC) achieves initial operational status in 2019. A 2015 study commissioned by the HPCMP found that N-ESPC computational requirements will exceed interconnect bandwidth capacity due to the additional load from data assimilation and passing connecting data between ensemble codes. Memory bandwidth and I/O bandwidth will continue to be significant bottlenecks for the Navy's Hybrid Coordinate Ocean Model (HYCOM) scalability - by far the major driver of computing resource requirements in the N-ESPC. The study also found that few of the N-ESPC model developers have detailed plans to ensure their respective codes scale through 2024. Three HPCMP initiatives are designed to directly address and support these issues: Productivity Enhancement, Technology, Transfer and Training (PETTT), the HPCMP Applications Software Initiative (HASI), and Frontier Projects. PETTT supports code conversion by providing assistance, expertise and training in scalable and high-end computing architectures. HASI addresses the continuing need for modern application software that executes effectively and efficiently on next-generation high-performance computers. Frontier Projects enable research and development that could not be achieved using typical HPCMP resources by providing multi-disciplinary teams access to exceptional amounts of high performance computing resources. Finally, the Navy's DoD Supercomputing Resource Center (DSRC) currently operates a 6 Petabyte system, of which Naval Oceanography receives 15% of operational computational system use, or approximately 1 Petabyte of the processing capability. The DSRC will

  4. Portable kit for high-throughput analysis of polycyclic aromatic hydrocarbons using surface enhanced Raman scattering after dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Zhang, Min; Zhang, Xiaoli; Qu, Baofeng; Zhan, Jinhua

    2017-12-01

    In this work, a portable kit was developed for convenient high-throughput trace analysis of polycyclic aromatic hydrocarbons (PAHs) using surface enhanced Raman scattering (SERS) after dispersive liquid-liquid microextraction (DLLME) process. This portable kit contains three sealed reagent tubes (labeled as T1, T2 and T3), a self-made well plate, and a portable Raman spectrometer. The reagent tube T1 contains a mixture of disperser solvent and extraction solvent, which involved a 2min sample pretreatment of DLLME process. The quick injection of solvents in tube T1 into the sample containing PAHs formed a cloudy solution immediately, which consists of fine droplets of extraction solvent dispersed entirely into aqueous phase. The enrichment factor was found to be 29.6. T2 and T3 contain methanol and 1-propanethiol-modified silver nanoparticles (PTH-Ag NPs), respectively. The liquid in the tube T3 was used to enhance the Raman signal of analytes on the self-made high-throughput micro reactor. A linear relationship between the concentration of pyrene and the relative Raman peak intensity was obtained (R(2) = 0.993). The detection limit was 0.50μgL(-1) for pyrene. RSD of the high-throughput analysis of 12 samples was calculated as 4.8%. The ability of DLLME-SERS technique in the extraction of PAH isomers from water samples were investigated. The performance of DLLME-SERS in the recovery of pyrene from lake, spring and drinking water was also studied. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Initial demonstration of the NRC`s capability to conduct a performance assessment for a High-Level Waste Repository

    Energy Technology Data Exchange (ETDEWEB)

    Codell, R.; Eisenberg, N.; Fehringer, D.; Ford, W.; Margulies, T.; McCartin, T.; Park, J.; Randall, J.

    1992-05-01

    In order to better review licensing submittals for a High-Level Waste Repository, the US Nuclear Regulatory Commission staff has expanded and improved its capability to conduct performance assessments. This report documents an initial demonstration of this capability. The demonstration made use of the limited data from Yucca Mountain, Nevada to investigate a small set of scenario classes. Models of release and transport of radionuclides from a repository via the groundwater and direct release pathways provided preliminary estimates of releases to the accessible environment for a 10,000 year simulation time. Latin hypercube sampling of input parameters was used to express results as distributions and to investigate model sensitivities. This methodology demonstration should not be interpreted as an estimate of performance of the proposed repository at Yucca Mountain, Nevada. By expanding and developing the NRC staff capability to conduct such analyses, NRC would be better able to conduct an independent technical review of the US Department of Energy (DOE) licensing submittals for a high-level waste (HLW) repository. These activities were divided initially into Phase 1 and Phase 2 activities. Additional phases may follow as part of a program of iterative performance assessment at the NRC. The NRC staff conducted Phase 1 activities primarily in CY 1989 with minimal participation from NRC contractors. The Phase 2 activities were to involve NRC contractors actively and to provide for the transfer of technology. The Phase 2 activities are scheduled to start in CY 1990, to allow Sandia National Laboratories to complete development and transfer of computer codes and the Center for Nuclear Waste Regulatory Analyses (CNWRA) to be in a position to assist in the acquisition of the codes.

  6. Portable Sequentially Shifted Excitation Raman spectroscopy as an innovative tool for in situ chemical interrogation of painted surfaces.

    Science.gov (United States)

    Conti, Claudia; Botteon, Alessandra; Bertasa, Moira; Colombo, Chiara; Realini, Marco; Sali, Diego

    2016-08-07

    We present the first validation and application of portable Sequentially Shifted Excitation (SSE) Raman spectroscopy for the survey of painted layers in art. The method enables the acquisition of shifted Raman spectra and the recovery of the spectral data through the application of a suitable reconstruction algorithm. The technique has a great potentiality in art where commonly a strong fluorescence obscures the Raman signal of the target, especially when conventional portable Raman spectrometers are used for in situ analyses. Firstly, the analytical capability of portable SSE Raman spectroscopy is critically discussed using reference materials and laboratory specimens, comparing its results with other conventional high performance laboratory instruments (benchtop FT-Raman and dispersive Raman spectrometers with an external fiber optic probe); secondly, it is applied directly in situ to study the complex polychromy of Italian prestigious terracotta sculptures of the 16(th) century. Portable SSE Raman spectroscopy represents a new investigation modality in art, expanding the portfolio of non-invasive, chemically specific analytical tools.

  7. Dynamic capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    it was dominated by a lack of systematism, assessment, monitoring, marketing speculations and feasibility calculation. Furthermore, the sphere was dictated by asymmetric supplier-customer relationships and negotiation power leading, among other possible factors, to meager profitability.......The consequences of dynamic capabilities (i.e. innovation performance and profitability) is an under researched area in the growing body of literature on dynamic capabilities and innovation management. This study aims to examine the relationship between dynamic capabilities, innovation performance...... and profitability of small and medium sized manufacturing enterprises operating in volatile environments. A multi-case study design was adopted as research strategy. The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case companies, as we would expect. It was...

  8. Graphene/LiMn{sub 2}O{sub 4} nanocomposites for enhanced lithium ion batteries with high rate capability

    Energy Technology Data Exchange (ETDEWEB)

    Pyun, Min Ho; Park, Yong Joon, E-mail: yjpark2006@kyonggi.ac.kr

    2015-09-15

    Highlights: • Composites of LiMn{sub 2}O{sub 4} nanoparticles in a graphene matrix were prepared. • The graphene/LiMn{sub 2}O{sub 4} electrode showed enhanced discharge capacity and rate capability. • This is attributed to the high surface area of LiMn{sub 2}O{sub 4} and good electronic conductivity of graphene. - Abstract: Composites of LiMn{sub 2}O{sub 4} nanoparticles in a graphene matrix were prepared to compensate for the low electronic conductivity of the LiMn{sub 2}O{sub 4} cathode. The LiMn{sub 2}O{sub 4} nanoparticles were homogeneously dispersed and attached on the graphene surface by the hydrothermal method. The graphene/LiMn{sub 2}O{sub 4} electrode showed higher discharge capacity and rate capability than a pristine LiMn{sub 2}O{sub 4} electrode. This is attributed to the high surface area of LiMn{sub 2}O{sub 4} nanoparticles and good electronic conductivity because of the presence of graphene. The composites of LiMn{sub 2}O{sub 4} nanoparticles with graphene were also effective in stabilizing the cyclic performance of the LiMn{sub 2}O{sub 4} nanoparticle cathode.

  9. Over-five octaves wide Raman combs in high-power picosecond-laser pumped H(2)-filled inhibited coupling Kagome fiber.

    Science.gov (United States)

    Benoît, Aurélien; Beaudou, Benoit; Alharbi, Meshaal; Debord, Benoit; Gérôme, Frédéric; Salin, François; Benabid, Fetah

    2015-06-01

    We report on the generation of over 5 octaves wide Raman combs using inhibited coupling Kagome guiding hollow-core photonic crystal fiber filled with hydrogen and pumped with 22.7 W average power and 27 picosecond pulsed fiber laser. Combs spanning from ~321 nm in the UV to ~12.5 µm in the long-wavelength IR (i.e. from 24 THz to 933 THz) with different spectral content and with an output average power of up to ~10 W were generated. In addition to the clear potential of such a comb as a laser source emitting at spectral ranges, which existing technology poorly addresses like long-wavelength IR and UV, the combination of high Raman net gain and short pump-pulse duration makes these spectra an excellent candidate for intra-pulse waveform synthesis.

  10. Raman micro-spectroscopy of UOX and MOX spent nuclear fuel characterization and oxidation resistance of the high burn-up structure

    Science.gov (United States)

    Jegou, C.; Gennisson, M.; Peuget, S.; Desgranges, L.; Guimbretière, G.; Magnin, M.; Talip, Z.; Simon, P.

    2015-03-01

    Raman micro-spectroscopy was applied to study the structure and oxidation resistance of UO2 (burnup 60 GWd/tHM) and MOX (burnup 47 GWd/tHM) irradiated fuels. The Raman technique, adapted to working under extreme conditions, enabled structural information to be obtained at the cubic micrometer scale in various zones of interest within irradiated fuel (central and zones like the Rim for UOX60, and the plutonium-enriched agglomerates for MOX47 characterized by a high burn-up structure), and the study of their oxidation resistance. As regards the structural information after irradiation, the spectra obtained make up a set of data consistent with the systematic presence of the T2g band characteristic of the fluorite structure, and of a triplet band located between 500 and 700 cm-1. The existence of this triplet can be attributed to the presence of defects originating in changes to the fuel chemistry occurring in the reactor (presence of fission products) and to the accumulation of irradiation damage. As concerns the oxidation resistance of the different zones of interest, Raman spectroscopy results confirmed the good stability of the restructured zones (plutonium-enriched agglomerates and Rim) rich in fission products compared to the non-restructured UO2 grains. A greater structural stability was noticed in the case of high plutonium content agglomerates, as this element favors the maintenance of the fluorite structure.

  11. High-pressure X-ray diffraction and Raman spectroscopy of CaFe2O4-type β-CaCr2O4

    Science.gov (United States)

    Zhai, Shuangmeng; Yin, Yuan; Shieh, Sean R.; Shan, Shuangming; Xue, Weihong; Wang, Ching-Pao; Yang, Ke; Higo, Yuji

    2016-04-01

    In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopic studies of orthorhombic CaFe2O4-type β-CaCr2O4 chromite were carried out up to 16.2 and 32.0 GPa at room temperature using multi-anvil apparatus and diamond anvil cell, respectively. No phase transition was observed in this study. Fitting a third-order Birch-Murnaghan equation of state to the P-V data yields a zero-pressure volume of V 0 = 286.8(1) Å3, an isothermal bulk modulus of K 0 = 183(5) GPa and the first pressure derivative of isothermal bulk modulus K 0' = 4.1(8). Analyses of axial compressibilities show anisotropic elasticity for β-CaCr2O4 since the a-axis is more compressible than the b- and c-axis. Based on the obtained and previous results, the compressibility of several CaFe2O4-type phases was compared. The high-pressure Raman spectra of β-CaCr2O4 were analyzed to determine the pressure dependences and mode Grüneisen parameters of Raman-active bands. The thermal Grüneisen parameter of β-CaCr2O4 is determined to be 0.93(2), which is smaller than those of CaFe2O4-type CaAl2O4 and MgAl2O4.

  12. Synthesis of copolymerized porous organic frameworks with high gas storage capabilities at both high and low pressures.

    Science.gov (United States)

    Pei, Cuiying; Ben, Teng; Li, Yanqiang; Qiu, Shilun

    2014-06-11

    A series of copolymerized porous organic frameworks (C-POFs) were synthesized with monomers of tetrakis(4-bromophenyl)methane and tris(4-bromophenyl)amine in different ratios by a Yamamoto-type Ullmann cross-coupling reaction. These C-POFs exhibit high physicochemical stability, large surface areas and excellent H2, CH4 and CO2 adsorption properties both at low and high pressures.

  13. Synthesis of copolymerized porous organic frameworks with high gas storage capabilities at both high and low pressures

    KAUST Repository

    Pei, Cuiying

    2014-01-01

    A series of copolymerized porous organic frameworks (C-POFs) were synthesized with monomers of tetrakis(4-bromophenyl)methane and tris(4-bromophenyl)amine in different ratios by a Yamamoto-type Ullmann cross-coupling reaction. These C-POFs exhibit high physicochemical stability, large surface areas and excellent H2, CH4 and CO 2 adsorption properties both at low and high pressures. This journal is © the Partner Organisations 2014.

  14. Exploiting the multiplexing capabilities of tandem mass tags for high-throughput estimation of cellular protein abundances by mass spectrometry.

    Science.gov (United States)

    Ahrné, Erik; Martinez-Segura, Amalia; Syed, Afzal Pasha; Vina-Vilaseca, Arnau; Gruber, Andreas J; Marguerat, Samuel; Schmidt, Alexander

    2015-09-01

    The generation of dynamic models of biological processes critically depends on the determination of precise cellular concentrations of biomolecules. Measurements of system-wide absolute protein levels are particularly valuable information in systems biology. Recently, mass spectrometry based proteomics approaches have been developed to estimate protein concentrations on a proteome-wide scale. However, for very complex proteomes, fractionation steps are required, increasing samples number and instrument analysis time. As a result, the number of full proteomes that can be routinely analyzed is limited. Here we combined absolute quantification strategies with the multiplexing capabilities of isobaric tandem mass tags to determine cellular protein abundances in a high throughput and proteome-wide scale even for highly complex biological systems, such as a whole human cell line. We generated two independent data sets to demonstrate the power of the approach regarding sample throughput, dynamic range, quantitative precision and accuracy as well as proteome coverage in comparison to existing mass spectrometry based strategies.

  15. Hierarchical sulfur electrodes as a testing platform for understanding the high-loading capability of Li-S batteries

    Science.gov (United States)

    Chung, Sheng-Heng; Chang, Chi-Hao; Manthiram, Arumugam

    2016-12-01

    Lithium-sulfur (Li-S) batteries are considered as an attractive electrochemical energy storage system due to the high theoretical capacity of sulfur (1,675 mA h g-1). However, high-loading sulfur cathodes would need to be employed for the Li-S cells to be practical, but the resulting poor cell cyclability and severe electrode degradation hamper their development. Here, we present a hierarchical sulfur cathode as a testing platform for understanding the high-loading capability of Li-S batteries. The hierarchical cathode presents good electrochemical utilization of above 70%, stable cyclability for 500-1,000 cycles, and high sulfur loadings of 4.2-10.0 mg cm-2. The exploration of the activation and the polysulfide-retention processes of the high-loading cathodes illustrates that the electrochemical stability mainly results from the stabilization of dissolved polysulfides within the cathode region as the electrochemically active catholyte. Therefore, the utilization of stabilized polysulfide migration might be a meaningful opportunity for designing high-loading cathodes and further improving their electrochemical stability and long-term cyclability.

  16. Studies of challenge in lower hybrid current drive capability at high density regime in experimental advanced superconducting tokamak

    Science.gov (United States)

    Ding, B. J.; Li, M. H.; Li, Y. C.; Wang, M.; Liu, F. K.; Shan, J. F.; Li, J. G.; Wan, B. N.; Wan

    2017-02-01

    Aiming at a fusion reactor, two issues must be solved for the lower hybrid current drive (LHCD), namely good lower hybrid wave (LHW)-plasma coupling and effective current drive at high density. For this goal, efforts have been made to improve LHW-plasma coupling and current drive capability at high density in experimental advanced superconducting tokamak (EAST). LHW-plasma coupling is improved by means of local gas puffing and gas puffing from the electron side is taken as a routine way for EAST to operate with LHCD. Studies of high density experiments suggest that low recycling and high lower hybrid (LH) frequency are preferred for LHCD experiments at high density, consistent with previous results in other machines. With the combination of 2.45 GHz and 4.6 GHz LH waves, a repeatable high confinement mode plasma with maximum density up to 19~\\text{m}-3$ was obtained by LHCD in EAST. In addition, in the first stage of LHCD cyclic operation, an alternative candidate for more economical fusion reactors has been demonstrated in EAST and further work will be continued.

  17. High capacity and high rate capability of nitrogen-doped porous hollow carbon spheres for capacitive deionization

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Shanshan; Yan, Tingting; Wang, Hui; Chen, Guorong; Huang, Lei; Zhang, Jianping; Shi, Liyi; Zhang, Dengsong, E-mail: dszhang@shu.edu.cn

    2016-04-30

    Graphical abstract: - Highlights: • The nitrogen-doped porous hollow carbon spheres were prepared. • The obtained materials have a good capacitive deionization performance. • The electrodes show high salt adsorption rate and good regeneration performance. - Abstract: In this work, nitrogen-doped porous hollow carbon spheres (N-PHCS) were well prepared by using polystyrene (PS) spheres as hard templates and dopamine hydrochloride as carbon and nitrogen sources. Field emission scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images demonstrate that the N-PHCS have a uniform, spherical and hollow structure. Nitrogen adsorption–desorption analysis shows that the N-PHCS have a high specific area of 512 m{sup 2}/g. X-ray photoelectron spectroscopy result reveals that the nitrogen doping amount is 2.92%. The hollow and porous structure and effective nitrogen doping can contribute to large accessible surface area, efficient ion transport and good conductivity. In the electrochemical tests, we can conclude that the N-PHCS have a high specific capacitance value, a good stability and low inner resistance. The N-PHCS electrodes present a high salt adsorption capacity of 12.95 mg/g at a cell voltage of 1.4 V with a flow rate of 40 mL/min in a 500 mg/L NaCl aqueous solution. Moreover, the N-PHCS electrodes show high salt adsorption rate and good regeneration performance in the CDI process. With high surface specific area and effective nitrogen doping, the N-PHCS is promising to the CDI and other electrochemical applications.

  18. Automated processing of label-free Raman microscope images of macrophage cells with standardized regression for high-throughput analysis.

    Science.gov (United States)

    Milewski, Robert J; Kumagai, Yutaro; Fujita, Katsumasa; Standley, Daron M; Smith, Nicholas I

    2010-11-19

    Macrophages represent the front lines of our immune system; they recognize and engulf pathogens or foreign particles thus initiating the immune response. Imaging macrophages presents unique challenges, as most optical techniques require labeling or staining of the cellular compartments in order to resolve organelles, and such stains or labels have the potential to perturb the cell, particularly in cases where incomplete information exists regarding the precise cellular reaction under observation. Label-free imaging techniques such as Raman microscopy are thus valuable tools for studying the transformations that occur in immune cells upon activation, both on the molecular and organelle levels. Due to extremely low signal levels, however, Raman microscopy requires sophisticated image processing techniques for noise reduction and signal extraction. To date, efficient, automated algorithms for resolving sub-cellular features in noisy, multi-dimensional image sets have not been explored extensively. We show that hybrid z-score normalization and standard regression (Z-LSR) can highlight the spectral differences within the cell and provide image contrast dependent on spectral content. In contrast to typical Raman imaging processing methods using multivariate analysis, such as single value decomposition (SVD), our implementation of the Z-LSR method can operate nearly in real-time. In spite of its computational simplicity, Z-LSR can automatically remove background and bias in the signal, improve the resolution of spatially distributed spectral differences and enable sub-cellular features to be resolved in Raman microscopy images of mouse macrophage cells. Significantly, the Z-LSR processed images automatically exhibited subcellular architectures whereas SVD, in general, requires human assistance in selecting the components of interest. The computational efficiency of Z-LSR enables automated resolution of sub-cellular features in large Raman microscopy data sets without

  19. High power nano-LiMn2O4 cathode materials with high-rate pulse discharge capability for lithium-ion batteries

    Institute of Scientific and Technical Information of China (English)

    Chen Ying-Chao; Xie Kai; Pan Yi; Zheng Chun-Man; Wang Hua-Lin

    2011-01-01

    Nano-LiMn2O4 cathode materials with nano-sized particles are synthesized via a citric acid assisted sol-gel route. The structure, the morphology and the electrochemical properties of the nano-LiMn2O4 are investigated. Compared with the micro-sized LiMn2O4, the nano-LiMn2O4 possesses a high initial capacity (120 mAh/g) at a discharge rate of 0.2 C (29.6 mA/g). The nano-LiMn2O4 also has a good high-rate discharge capability, retaining 91% of its capacity at a discharge rate of 10 C and 73% at a discharge rate of 40 C. In particular, the nano-LiMn2O4 shows an excellent high-rate pulse discharge capability. The cut-off voltage at the end of 50-ms pulse discharge with a discharge rate of 80 C is above 3.40 V, and the voltage returns to over 4.10 V after the pulse discharge. These results show that the prepared nano-LiMn2O4 could be a potential cathode material for the power sources with the capability to deliver very high-rate pulse currents.

  20. Using analytic hierarchy process to identify the nurses with high stress-coping capability: model and application.

    Science.gov (United States)

    F C Pan, Frank

    2014-03-01

    Nurses have long been relied as the major labor force in hospitals. Featured with complicated and highly labor-intensive job requirement, multiple pressures from different sources was inevitable. Success in identifying stresses and accordingly coping with such stresses is important for job performance of nurses, and service quality of a hospital. Purpose of this research is to identify the determinants of nurses' capabilities. A modified Analytic Hierarchy Process (AHP) was adopted. Overall, 105 nurses from several randomly selected hospitals in southern Taiwan were investigated to generate factors. Ten experienced practitioners were included as the expert in the AHP to produce weights of each criterion. Six nurses from two regional hospitals were then selected to test the model. Four factors are then identified as the second level of hierarchy. The study result shows that the family factor is the most important factor, and followed by the personal attributes. Top three sub-criteria that attribute to the nurse's stress-coping capability are children's education, good career plan, and healthy family. The practical simulation provided evidence for the usefulness of this model. The study suggested including these key determinants into the practice of human-resource management, and restructuring the hospital's organization, creating an employee-support system as well as a family-friendly working climate. The research provided evidence that supports the usefulness of AHP in identifying the key factors that help stabilizing a nursing team.

  1. Using analytic hierarchy process to identify the nurses with high stress-coping capability: model and application.

    Directory of Open Access Journals (Sweden)

    Frank F C Pan

    2014-03-01

    Full Text Available Nurses have long been relied as the major labor force in hospitals. Featured with complicated and highly labor-intensive job requirement, multiple pressures from different sources was inevitable. Success in identifying stresses and accordingly coping with such stresses is important for job performance of nurses, and service quality of a hospital. Purpose of this research is to identify the determinants of nurses' capabilities.A modified Analytic Hierarchy Process (AHP was adopted. Overall, 105 nurses from several randomly selected hospitals in southern Taiwan were investigated to generate factors. Ten experienced practitioners were included as the expert in the AHP to produce weights of each criterion. Six nurses from two regional hospitals were then selected to test the model.Four factors are then identified as the second level of hierarchy. The study result shows that the family factor is the most important factor, and followed by the personal attributes. Top three sub-criteria that attribute to the nurse's stress-coping capability are children's education, good career plan, and healthy family. The practical simulation provided evidence for the usefulness of this model.The study suggested including these key determinants into the practice of human-resource management, and restructuring the hospital's organization, creating an employee-support system as well as a family-friendly working climate. The research provided evidence that supports the usefulness of AHP in identifying the key factors that help stabilizing a nursing team.

  2. Etched colloidal LiFePO4 nanoplatelets toward high-rate capable Li-ion battery electrodes.

    Science.gov (United States)

    Paolella, Andrea; Bertoni, Giovanni; Marras, Sergio; Dilena, Enrico; Colombo, Massimo; Prato, Mirko; Riedinger, Andreas; Povia, Mauro; Ansaldo, Alberto; Zaghib, Karim; Manna, Liberato; George, Chandramohan

    2014-12-10

    LiFePO4 has been intensively investigated as a cathode material in Li-ion batteries, as it can in principle enable the development of high power electrodes. LiFePO4, on the other hand, is inherently "plagued" by poor electronic and ionic conductivity. While the problems with low electron conductivity are partially solved by carbon coating and further by doping or by downsizing the active particles to nanoscale dimensions, poor ionic conductivity is still an issue. To develop colloidally synthesized LiFePO4 nanocrystals (NCs) optimized for high rate applications, we propose here a surface treatment of the NCs. The particles as delivered from the synthesis have a surface passivated with long chain organic surfactants, and therefore can be dispersed only in aprotic solvents such as chloroform or toluene. Glucose that is commonly used as carbon source for carbon-coating procedure is not soluble in these solvents, but it can be dissolved in water. In order to make the NCs hydrophilic, we treated them with lithium hexafluorophosphate (LiPF6), which removes the surfactant ligand shell while preserving the structural and morphological properties of the NCs. Only a roughening of the edges of NCs was observed due to a partial etching of their surface. Electrodes prepared from these platelet NCs (after carbon coating) delivered a capacity of ∼ 155 mAh/g, ∼ 135 mAh/g, and ∼ 125 mAh/g, at 1 C, 5 C, and 10 C, respectively, with significant capacity retention and remarkable rate capability. For example, at 61 C (10.3 A/g), a capacity of ∼ 70 mAh/g was obtained, and at 122 C (20.7 A/g), the capacity was ∼ 30 mAh/g. The rate capability and the ease of scalability in the preparation of these surface-treated nanoplatelets make them highly suitable as electrodes in Li-ion batteries.

  3. Raman Studies of Carbon Nanostructures

    Science.gov (United States)

    Jorio, Ado; Souza Filho, Antonio G.

    2016-07-01

    This article reviews recent advances on the use of Raman spectroscopy to study and characterize carbon nanostructures. It starts with a brief survey of Raman spectroscopy of graphene and carbon nanotubes, followed by recent developments in the field. Various novel topics, including Stokes-anti-Stokes correlation, tip-enhanced Raman spectroscopy in two dimensions, phonon coherence, and high-pressure and shielding effects, are presented. Some consequences for other fields—quantum optics, near-field electromagnetism, archeology, materials and soil sciences—are discussed. The review ends with a discussion of new perspectives on Raman spectroscopy of carbon nanostructures, including how this technique can contribute to the development of biotechnological applications and nanotoxicology.

  4. In situ precise electrospinning of medical glue fibers as nonsuture dural repair with high sealing capability and flexibility

    Science.gov (United States)

    Lv, Fu-Yan; Dong, Rui-Hua; Li, Zhao-Jian; Qin, Chong-Chong; Yan, Xu; He, Xiao-Xiao; Zhou, Yu; Yan, Shi-Ying; Long, Yun-Ze

    2016-01-01

    Purpose In this work, we propose an in situ precise electrospinning of medical glue fibers onto dural wound for improving sealing capability, avoiding tissue adhesion, and saving time in dural repair. Methods N-octyl-2-cyanoacrylate, a commercial tissue adhesive (medical glue), can be electrospun into ultrathin fibrous film with precise and homogeneous deposition by a gas-assisted electrospinning device. Results The self-assembled N-octyl-2-cyanoacrylate film shows high compactness and flexibility owing to its fibrous structure. Simulation experiments on egg membranes and goat meninges demonstrated that this technology can repair small membrane defects quickly and efficiently. Conclusion This method may have potential application in dural repair, for example, working as an effective supplementary technique for conventional dura suture. PMID:27621616

  5. Development of 2.8 V Ketjen black supercapacitors with high rate capabilities for AC line filtering

    Science.gov (United States)

    Yoo, Yongju; Park, Jinwoo; Kim, Min-Seop; Kim, Woong

    2017-08-01

    Supercapacitors are generally more compact than conventional bulky aluminum electrolytic capacitors (AECs). Replacement of AECs with supercapacitors can lead to miniaturization of electronic devices. However, even state-of-the-art supercapacitors developed in laboratories are superior to or competitive with AECs only in low voltage applications (values of ∼574 μF cm-2, 2.8 V, and ∼-80°, respectively. In addition, we demonstrate that an AC line filtering circuit with three supercapacitors connected in series can extend the application voltage without significant sacrifice in rate capability (ϕ ∼ -77° at 120 Hz). On the other hand, KBs are much less expensive than carbon materials previously demonstrated for AC line filtering and hence are very attractive for practical applications. We believe that this demonstration of high-performance supercapacitors made from low-cost carbon materials is both scientifically interesting and important for practical applications.

  6. High expression of osteoglycin decreases the metastatic capability of mouse hepatocarcinoma Hca-F cells to lymph nodes

    Institute of Scientific and Technical Information of China (English)

    Xiaonan Cui; Bo Song; Li Hou; Zhiyi Wei; Jianwu Tang

    2008-01-01

    Osteoglycin, one of the matrix molecules, belongs to the small leucine-rich proteoglycan gene family and might play important roles in cell growth and differentiation and in pathological processes such as fibrosis and cancer growth.In this study, a eukaryotic expression plasmid pIRESpuro3 osteoglycin(+) was constructed and transfected into mouse hepatocarcinoma Hca-F cells to evaluate the contribution of osteoglycin to the malignant behavior of Hca-F. It was foundthat Hca-F cells transfected with pIRESpuro3 osteoglycin(+) showed significantly decreased potential for both migration and invasion. Furthermore, Hca-F cells transfected with osteoglycin showed decreased metastatic potential to peripheral lymph nodes. However, proliferation potential and adhesive capacity of Hca-F cells to different protein substrates were not influenced by osteoglycin transfection. In summary,high expression of osteoglycin decreases the metastatic capability of Hca-F to lymph nodes.

  7. Improving high carbon dioxide tolerance and carbon dioxide fixation capability of Chlorella sp. by adaptive laboratory evolution.

    Science.gov (United States)

    Li, Dengjin; Wang, Liang; Zhao, Quanyu; Wei, Wei; Sun, Yuhan

    2015-06-01

    CO2 capture by microalgae is a promising method to reduce greenhouse gas emissions. It is critical to construct a highly efficient way to obtain a microalgal strain tolerant to high CO2 concentrations with high CO2 fixation capability. In this study, two evolved Chlorella sp. strains, AE10 and AE20 were obtained after 31 cycles of adaptive laboratory evolution (ALE) under 10% and 20% CO2, respectively. Both of them grew rapidly in 30% CO2 and the maximal biomass concentration of AE10 was 3.68±0.08g/L, which was 1.22 and 2.94 times to those of AE20 and original strain, respectively. The chlorophyll contents of AE10 and AE20 were significantly higher than those of the original one under 1-30% CO2. The influences of ALE process on biochemical compositions of Chlorella cells were also investigated. This study proved that ALE was an effective approach to improve high CO2 tolerance of Chlorella sp.

  8. Weavable, Conductive Yarn-Based NiCo//Zn Textile Battery with High Energy Density and Rate Capability.

    Science.gov (United States)

    Huang, Yan; Ip, Wing Shan; Lau, Yuen Ying; Sun, Jinfeng; Zeng, Jie; Yeung, Nga Sze Sea; Ng, Wing Sum; Li, Hongfei; Pei, Zengxia; Xue, Qi; Wang, Yukun; Yu, Jie; Hu, Hong; Zhi, Chunyi

    2017-09-26

    With intrinsic safety and much higher energy densities than supercapacitors, rechargeable nickel/cobalt-zinc-based textile batteries are promising power sources for next generation personalized wearable electronics. However, high-performance wearable nickel/cobalt-zinc-based batteries are rarely reported because there is a lack of industrially weavable and knittable highly conductive yarns. Here, we use scalably produced highly conductive yarns uniformly covered with zinc (as anode) and nickel cobalt hydroxide nanosheets (as cathode) to fabricate rechargeable yarn batteries. They possess a battery level capacity and energy density, as well as a supercapacitor level power density. They deliver high specific capacity of 5 mAh cm(-3) and energy densities of 0.12 mWh cm(-2) and 8 mWh cm(-3) (based on the whole solid battery). They exhibit ultrahigh rate capabilities of 232 C (liquid electrolyte) and 116 C (solid electrolyte), which endows the batteries excellent power densities of 32.8 mW cm(-2) and 2.2 W cm(-3) (based on the whole solid battery). These are among the highest values reported so far. A wrist band battery is further constructed by using a large conductive cloth woven from the conductive yarns by a commercial weaving machine. It powers various electronic devices successfully, enabling dual functions of wearability and energy storage.

  9. Capability approach

    DEFF Research Database (Denmark)

    Jensen, Niels Rosendal; Kjeldsen, Christian Christrup

    Lærebogen er den første samlede danske præsentation af den af Amartya Sen og Martha Nussbaum udviklede Capability Approach. Bogen indeholder en præsentation og diskussion af Sen og Nussbaums teoretiske platform. I bogen indgår eksempler fra såvel uddannelse/uddannelsespolitik, pædagogik og omsorg....

  10. ENTREPRENEURIAL CAPABILITIES

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard; Nielsen, Thorkild

    2003-01-01

    The aim of this article is to analyse entrepreneurship from an action research perspective. What is entrepreneurship about? Which are the fundamental capabilities and processes of entrepreneurship? To answer these questions the article includes a case study of a Danish entrepreneur and his networks...

  11. 方解石高压相变的拉曼光谱研究%Research on Raman Spectra of Calcite Phase Transition at High Pressure

    Institute of Scientific and Technical Information of China (English)

    王世霞; 郑海飞

    2011-01-01

    he present research studied the process of phase transition from calcite-I to calcite- III under the condition of high hydrostatic pressure using hydrothermal diamond anvil cell and Raman spectrum technique. The hydrothermal diamond anvil cell is the most useful instrument to observe sample in-situation under high temperature and high pressure. The authors can get effective results from this instrument and pursue further research. The method of Raman spectra is the most useful measure tool and it can detect the material according to the spectrum. The result shows that three characteristic Raman peaks of calcite-I move to high-position with adding pressure. Water media in system becomes frozen at the pressure of 1 103 Mpa, and there is no change in the structure of calcite- I. The abrupt change of characteristic Raman peaks of calcite -I happens when the system pressure reaches 1 752 Mpa, and changed characteristic Raman peaks explain that calcite-I changes to calcite-III. There are two types of calcite-III and type A happens in the system because of the effect of hydrostatic pressure. The characteristic Raman peak in different areas of minerals shows that the degree of phase transition becomes larger from inner part to edge part The research also shows the advantage of hydrothermal diamond anvil cell and Raman spectrum for qualitative analysis of mineral structure using in-situ technique.%应用金刚石压腔结合拉曼光谱技术研究了方解石-Ⅰ在静水高压作用下相转变为方解石-Ⅲ的过程.结果表明,压力增大的过程中,方解石-Ⅰ晶体的三个拉曼特征峰均向高频移动;在1 103 MPa条件下,体系中的水介质结冰,冰点处方解石-Ⅰ晶体性质没有变化;继续加压至1 752 MPa时矿物的拉曼特征峰发生了突变,表明晶体由方解石-Ⅰ相转变为方解石-Ⅲ相中的的A型方解石;相变后矿物的拉曼特征峰显示了从矿物内部向边缘的过渡中,相变程度逐渐增

  12. “Rings of saturn-like” nanoarrays with high number density of hot spots for surface-enhanced Raman scattering

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Zhigao; Liao, Lei; Wu, Wei; Guo, Shishang; Zhao, Xinyue; Li, Wei; Ren, Feng; Jiang, Changzhong, E-mail: xxh@whu.edu.cn, E-mail: czjiang@whu.edu.cn [Department of Physics, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072 (China); Mei, Fei [Department of Physics, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072 (China); School of Electrical and Electronic Engineering, Hubei University of Technology, Wuhan 430068 (China); Xiao, Xiangheng, E-mail: xxh@whu.edu.cn, E-mail: czjiang@whu.edu.cn [Department of Physics, Hubei Nuclear Solid Physics Key Laboratory and Center for Ion Beam Application, Wuhan University, Wuhan 430072 (China); Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095 (United States); Fu, Lei; Wang, Jiao [College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China)

    2014-07-21

    The Ag nanoparticles (NPs) surrounding triangular nanoarrays (TNAs) with high number density of surface-enhanced Raman scattering (SERS) hot spots (SERS hot spots ring) are prepared by a combination of NPs deposition and subsequent colloid lithography processing. Owing to the SERS hot spots ring, the Ag NPs surrounding TNAs have been proved an excellent candidate for ultrasensitive molecular sensing for their high SERS signal enhancing capacity in experiments and theories. The Ag NPs surrounding TNAs can be readily used for the quick detection of low concentrations of molecules related to food safety; herein, detection of melamine is discussed.

  13. Characterization of polymer composites by fiber optic Fourier transform Raman spectroscopy

    Science.gov (United States)

    Farquharson, Stuart; Bhat, Sanmitra A.; Osbaldiston, Richard; DiTaranto, Marie B.; Smith, Wayne W.; Rose, Jennifer; Liu, Yong-Ming; Shaw, Montgomery

    1999-01-01

    The in-use performance of polymer composites is highly dependent on the polymeric structure, which in turn, is highly dependent on the processing conditions. We have been developing a Fourier transform Raman system capable of high temperature measurements within curing devices through the use of fiber optic probes. The goal is to use real-time spectral data to control heat schedules and ultimately, composite properties. This presentation will describe the development of cure models based on reaction mechanisms for an epoxy resin and a polyimide using IR and Raman spectroscopy. It will also describe correlations between molecular structure and mechanical properties obtained by simultaneous Raman and rheology measurements. In addition, new spectral methods to determine cure kinetics will be presented.

  14. X-ray diffraction and Raman study of DL-alanine at high pressure: revision of phase transitions.

    Science.gov (United States)

    Tumanov, Nikolay A; Boldyreva, Elena V

    2012-08-01

    The effect of pressure on DL-alanine has been studied by X-ray powder diffraction (up to 8.3 GPa), single-crystal X-ray diffraction and Raman spectroscopy (up to ~6 GPa). No structural phase transitions have been observed. At ~1.5-2 GPa, cell parameters b and c become accidentally equal to each other, but the space-group symmetry does not change. There is no phase transition between 1.7 and 2.3 GPa, contrary to what has been reported earlier [Belo et al. (2010). Vibr. Spectrosc. 54, 107-111]. The presence of the second phase transition, which was claimed to appear within the pressure range from 6.0 to 7.3 GPa (Belo et al., 2010), is also argued. The changes in the Raman spectra have been shown to be continuous in all the pressure ranges studied.

  15. Effects of high pressure on the Raman and fluorescence emission spectra of two novel 1,3,4-oxadiazole derivatives

    Institute of Scientific and Technical Information of China (English)

    Luo Ji-Feng; Tang Ben-Chen; Gao Chun-Xiao; Li Min; Han Yong-Hao; Zou Guang-Tian

    2005-01-01

    The effects of pressure on the fluorescence emission and Raman spectra of 1,4-bis[(4-methyloxyphenyl)-1,3,4-oxadiazolyl]- 2,5-bisheptyloxyphenylene (OXD-2) and on the fluorescence emission spectra of 1,4-bis[(4-methylphenyl)-1,3,4-oxadiazolyl]phenylene (OXD-1) are investigated using a diamond anvil cell. With the increase of pressure, the intensity of the fluorescence emission increases and reaches maxima at 13GPa for OXD-1 and at 9.6GPa for OXD-2.The effect of pressure on the peak position of the emission shows a similar trend, red shift with the increase of pressure.But at higher pressures, the intensity of emission drops down dramatically. The Raman spectra of OXD-2 indicate that there appears a structural change at ca 3GPa.

  16. Multiferroic CuCrO₂ under high pressure: In situ X-ray diffraction and Raman spectroscopic studies

    Energy Technology Data Exchange (ETDEWEB)

    Garg, Alka B., E-mail: alkagarg@barc.gov.in; Mishra, A. K.; Pandey, K. K.; Sharma, Surinder M. [High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-10-07

    The compression behavior of delafossite compound CuCrO₂ has been investigated by in situ x-ray diffraction (XRD) and Raman spectroscopic measurements up to 23.2 and 34 GPa, respectively. X-ray diffraction data show the stability of ambient rhombohedral structure up to ~23 GPa. Material shows large anisotropy in axial compression with c-axis compressibility, κ{sub c} = 1.26 × 10⁻³(1) GPa⁻¹ and a-axis compressibility, κ{sub a} = 8.90 × 10⁻³(6) GPa⁻¹. Our XRD data show an irreversible broadening of diffraction peaks. Pressure volume data when fitted to 3rd order Birch-Murnaghan equation of state give the value of bulk modulus, B₀ = 156.7(2.8) GPa with its pressure derivative, B₀{sup ’} as 5.3(0.5). All the observed vibrational modes in Raman measurements show hardening with pressure. Appearance of a new mode at ~24 GPa indicates the structural phase transition in the compound. Our XRD and Raman results indicate that CuCrO{sub 2} may be transforming to an ordered rocksalt type structure under compression.

  17. Synthesis of highly efficient antibacterial agent Ag doped ZnO nanorods: Structural, Raman and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Jan, Tariq; Iqbal, Javed, E-mail: javed.saggu@iiu.edu.pk [Laboratory of Nanoscience and Technology, Department of Physics, International Islamic University Islamabad (Pakistan); Ismail, Muhammad [Institute of Biomedical and Genetic Engineering (IBGE), Islamabad (Pakistan); Mahmood, Arshad [Nano Devices Labs, National Institute of Lasers and Optronics, Islamabad (Pakistan)

    2014-04-21

    Here, synthesis, structural, morphological, Raman, optical properties and antibacterial activity of undoped and Ag doped ZnO nanorods by chemical co-precipitation technique have been reported. Structural analysis has revealed that Ag doping cannot deteriorate the structure of ZnO and wurtzite phase is maintained. Lattice constants are found to be decreased with the Ag doping. Fourier transform infrared and Raman spectroscopy also confirm the X-ray diffraction results. Scanning electron microscopy results have demonstrated the formation of ZnO nanorods with average diameter and length of 96 nm and 700 nm, respectively. Raman spectroscopy results suggest that the Ag doping enhances the number of defects in ZnO crystal. It has been found from optical study that Ag doping results in positional shift of band edge absorption peak. This is attributed to the successful incorporation of Ag dopant into ZnO host matrix. The antibacterial activity of prepared nanorods has been determined by two different methods and compared to that of undoped ZnO nanorods. Ag doped ZnO nanorods exhibit excellent antibacterial activity as compared to that of undoped ZnO nanorods. This excellent antibacterial activity may be attributed to the presence of oxygen vacancies and Zn{sup 2+} interstitial defects. Our preliminary findings suggest that Ag doped ZnO nanorods can be used externally to control the spreading of infections related with tested bacterial strains.

  18. Addressing capability computing challenges of high-resolution global climate modelling at the Oak Ridge Leadership Computing Facility

    Science.gov (United States)

    Anantharaj, Valentine; Norman, Matthew; Evans, Katherine; Taylor, Mark; Worley, Patrick; Hack, James; Mayer, Benjamin

    2014-05-01

    During 2013, high-resolution climate model simulations accounted for over 100 million "core hours" using Titan at the Oak Ridge Leadership Computing Facility (OLCF). The suite of climate modeling experiments, primarily using the Community Earth System Model (CESM) at nearly 0.25 degree horizontal resolution, generated over a petabyte of data and nearly 100,000 files, ranging in sizes from 20 MB to over 100 GB. Effective utilization of leadership class resources requires careful planning and preparation. The application software, such as CESM, need to be ported, optimized and benchmarked for the target platform in order to meet the computational readiness requirements. The model configuration needs to be "tuned and balanced" for the experiments. This can be a complicated and resource intensive process, especially for high-resolution configurations using complex physics. The volume of I/O also increases with resolution; and new strategies may be required to manage I/O especially for large checkpoint and restart files that may require more frequent output for resiliency. It is also essential to monitor the application performance during the course of the simulation exercises. Finally, the large volume of data needs to be analyzed to derive the scientific results; and appropriate data and information delivered to the stakeholders. Titan is currently the largest supercomputer available for open science. The computational resources, in terms of "titan core hours" are allocated primarily via the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) and ASCR Leadership Computing Challenge (ALCC) programs, both sponsored by the U.S. Department of Energy (DOE) Office of Science. Titan is a Cray XK7 system, capable of a theoretical peak performance of over 27 PFlop/s, consists of 18,688 compute nodes, with a NVIDIA Kepler K20 GPU and a 16-core AMD Opteron CPU in every node, for a total of 299,008 Opteron cores and 18,688 GPUs offering a cumulative 560

  19. Dynamic capabilities

    DEFF Research Database (Denmark)

    Grünbaum, Niels Nolsøe; Stenger, Marianne

    2013-01-01

    and profitability of small and medium sized manufacturing enterprises operating in volatile environments. A multi-case study design was adopted as research strategy. The findings reveal a positive relationship between dynamic capabilities and innovation performance in the case companies, as we would expect. It was...... it was dominated by a lack of systematism, assessment, monitoring, marketing speculations and feasibility calculation. Furthermore, the sphere was dictated by asymmetric supplier-customer relationships and negotiation power leading, among other possible factors, to meager profitability....

  20. Raman spectroscopy under extreme conditions

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, A F; Crowhurst, J C

    2004-11-05

    We report the results of Raman measurements of various materials under simultaneous conditions of high temperature and high pressure in the diamond anvil cell (DAC). High temperatures are generated by laser heating or internal resistive (ohmic) heating or a combination of both. We present Raman spectra of cubic boron nitride (cBN) to 40 GPa and up to 2300 K that show a continuous pressure and temperature shift of the frequency of the transverse optical mode. We have also obtained high-pressure Raman spectra from a new noble metal nitride, which we synthesized at approximately 50 GPa and 2000 K. We have obtained high-temperature spectra from pure nitrogen to 39 GPa and up to 2000 K, which show the presence of a hot band that has previously been observed in CARS measurements. These measurements have also allowed us to constrain the melting curve and to examine changes in the intramolecular potential with pressure.

  1. Evaluation of drug loading capabilities of γ-cyclodextrin-metal organic frameworks by high performance liquid chromatography.

    Science.gov (United States)

    Xu, Xiaonan; Wang, Caifen; Li, Haiyan; Li, Xue; Liu, Botao; Singh, Vikramjeet; Wang, Shuxia; Sun, Lixin; Gref, Ruxandra; Zhang, Jiwen

    2017-03-10

    Drug loading into γ-cyclodextrin-metal organic frameworks (γ-CD-MOFs) using the impregnation approach is a laborious process. In this study, a γ-CD-MOF construct (2-5μm particle diameter) was used as the stationary phase under HPLC conditions with the aim to correlate retention properties and drug loading capability of the CD-based structure. Ketoprofen, fenbufen and diazepam were chosen as model drugs with m-xylene as a control analyte to investigate the correlation of drug loading and their chromatographic behaviour in the γ-CD-MOF column. Furthermore, γ-CD itself was also prepared as the stationary phase by coupling with silica in the column to illustrate the enhanced interaction between drugs and γ-CD-MOF as a reference. The retention and loading efficiency of the drugs were determined with different ratios of hexane and ethanol (10:90, 20:80, 50:50, 80:20, 90:10, v/v) at temperatures of 20, 25, 30 and 37°C. With the increment in hexane content, the loading efficiency of ketoprofen and fenbufen increased from 2.39±0.06% to 4.38±0.04% and from 5.82±0.94% to 6.37±0.29%, respectively. The retention time and loading efficiency of ketoprofen and diazepam were the lowest at 30°C while those of fenbufen had the different tendency. The excellent relation between the retention and loading efficiency onto γ-CD-MOF could be clearly observed through mobile phase and temperature investigation. In conclusion, a highly efficient chromatographic method has been established to evaluate the drug loading capability of γ-CD-MOF.

  2. Quantitative Raman spectroscopy for the analysis of carrot bioactives.

    Science.gov (United States)

    Killeen, Daniel P; Sansom, Catherine E; Lill, Ross E; Eason, Jocelyn R; Gordon, Keith C; Perry, Nigel B

    2013-03-20

    Rapid quantitative near-infrared Fourier transform Raman analyses of the key phytonutrients in carrots, polyacetylenes and carotenoids, are reported here for the first time. Solvent extracts of 31 carrot lines were analyzed for these phytonutrients by conventional methods, polyacetylenes by GC-FID and carotenoids by visible spectrophotometry. Carotenoid concentrations were 0-5586 μg g(-1) dry weight (DW). Polyacetylene concentrations were 74-4846 μg g(-1) DW, highest in wild carrots. The polyacetylenes were falcarinol, 6-1237 μg g(-1) DW; falcarindiol, 42-3475 μg g(-1) DW; and falcarindiol 3-acetate, 27-649 μg g(-1) DW. Strong Raman bands for carotenoids gave good correlation to results by visible spectrophotometry. A chemometric model capable of quantitating carotenoids from Raman data was developed. A classification model for rapidly distinguishing carrots with high and low polyacetylene (limit of detection = 1400 μg g(-1)) concentrations based on Raman spectral intensity in the region of 2250 cm(-1) was produced.

  3. Carbon-Coated, Diatomite-Derived Nanosilicon as a High Rate Capable Li-ion Battery Anode

    Science.gov (United States)

    Campbell, Brennan; Ionescu, Robert; Tolchin, Maxwell; Ahmed, Kazi; Favors, Zachary; Bozhilov, Krassimir N.; Ozkan, Cengiz S.; Ozkan, Mihrimah

    2016-10-01

    Silicon is produced in a variety of ways as an ultra-high capacity lithium-ion battery (LIB) anode material. The traditional carbothermic reduction process required is expensive and energy-intensive; in this work, we use an efficient magnesiothermic reduction to convert the silica-based frustules within diatomaceous earth (diatomite, DE) to nanosilicon (nanoSi) for use as LIB anodes. Polyacrylic acid (PAA) was used as a binder for the DE-based nanoSi anodes for the first time, being attributed for the high silicon utilization under high current densities (up to 4C). The resulting nanoSi exhibited a high BET specific surface area of 162.6 cm2 g‑1, compared to a value of 7.3 cm2 g‑1 for the original DE. DE contains SiO2 architectures that make ideal bio-derived templates for nanoscaled silicon. The DE-based nanoSi anodes exhibit good cyclability, with a specific discharge capacity of 1102.1 mAh g‑1 after 50 cycles at a C-rate of C/5 (0.7 A gSi‑1) and high areal loading (2 mg cm‑2). This work also demonstrates the fist rate capability testing for a DE-based Si anode; C-rates of C/30 - 4C were tested. At 4C (14.3 A gSi‑1), the anode maintained a specific capacity of 654.3 mAh g‑1 – nearly 2x higher than graphite’s theoretical value (372 mAh g‑1).

  4. Raman and SEM analysis of a biocolonised hot spring travertine terrace in Svalbard, Norway

    Directory of Open Access Journals (Sweden)

    Jorge-Villar Susana E

    2007-08-01

    Full Text Available Abstract Background A profile across 8 layers from a fossil travertine terrace from a low temperature geothermal spring located in Svalbard, Norway has been studied using both Raman spectroscopy and SEM (Scanning Electron Microscopy techniques to identify minerals and organic life signals. Results Calcite, anatase, quartz, haematite, magnetite and graphite as well as scytonemin, three different carotenoids, chlorophyll and a chlorophyll-like compound were identified as geo- and biosignatures respectively, using 785 and/or 514 nm Raman laser excitation wavelengths. No morphological biosignatures representing remnant microbial signals were detected by high-resolution imaging, although spectral analyses indicated the presence of organics. In contrast, in all layers, Raman spectra identified a series of different organic pigments indicating little to no degradation or change of the organic signatures and thus indicating the preservation of fossil biomarker compounds throughout the life time of the springs despite the lack of remnant morphological indicators. Conclusion With a view towards planetary exploration we discuss the implications of the differences in Raman band intensities observed when spectra were collected with the different laser excitations. We show that these differences, as well as the different detection capability of the 785 and 514 nm laser, could lead to ambiguous compound identification. We show that the identification of bio and geosignatures, as well as fossil organic pigments, using Raman spectroscopy is possible. These results are relevant since both lasers have been considered for miniaturized Raman spectrometers for planetary exploration.

  5. Enhanced Uranium Ore Concentrate Analysis by Handheld Raman Sensor: FY15 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Samuel A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Timothy J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Orton, Christopher R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-11

    High-purity uranium ore concentrates (UOC) represent a potential proliferation concern. A cost-effective, “point and shoot” in-field analysis capability to identify ore types, phases of materials present, and impurities, as well as estimate the overall purity would be prudent. Handheld, Raman-based sensor systems are capable of identifying chemical properties of liquid and solid materials. While handheld Raman systems have been extensively applied to many other applications, they have not been broadly studied for application to UOC, nor have they been optimized for this class of chemical compounds. PNNL was tasked in Fiscal Year 2015 by the Office of International Safeguards (NA-241) to explore the use of Raman for UOC analysis and characterization. This report summarizes the activities in FY15 related to this project. The following tasks were included: creation of an expanded library of Raman spectra of a UOC sample set, creation of optimal chemometric analysis methods to classify UOC samples by their type and level of impurities, and exploration of the various Raman wavelengths to identify the ideal instrument settings for UOC sample interrogation.

  6. Highly crystallized nanometer-sized zeolite a with large Cs adsorption capability for the decontamination of water.

    Science.gov (United States)

    Torad, Nagy L; Naito, Masanobu; Tatami, Junichi; Endo, Akira; Leo, Sin-Yen; Ishihara, Shinsuke; Wu, Kevin C-W; Wakihara, Toru; Yamauchi, Yusuke

    2014-03-01

    Nanometer-sized zeolite A with a large cesium (Cs) uptake capability is prepared through a simple post-milling recrystallization method. This method is suitable for producing nanometer-sized zeolite in large scale, as additional organic compounds are not needed to control zeolite nucleation and crystal growth. Herein, we perform a quartz crystal microbalance (QCM) study to evaluate the uptake ability of Cs ions by zeolite, to the best of our knowledge, for the first time. In comparison to micrometer-sized zeolite A, nanometer-sized zeolite A can rapidly accommodate a larger amount of Cs ions into the zeolite crystal structure, owing to its high external surface area. Nanometer-sized zeolite is a promising candidate for the removal of radioactive Cs ions from polluted water. Our QCM study on Cs adsorption uptake behavior provides the information of adsorption kinetics (e.g., adsorption amounts and rates). This technique is applicable to other zeolites, which will be highly valuable for further consideration of radioactive Cs removal in the future.

  7. Multi-layer plastic scintillation detector for intermediate- and high-energy neutrons with n- γ discrimination capability

    Science.gov (United States)

    Yu, L.; Terashima, S.; Ong, H. J.; Chan, P. Y.; Tanihata, I.; Iwamoto, C.; Tran, D. T.; Tamii, A.; Aoi, N.; Fujioka, H.; Gey, G.; Sakaguchi, H.; Sakaue, A.; Sun, B. H.; Tang, T. L.; Wang, T. F.; Watanabe, Y. N.; Zhang, G. X.

    2017-09-01

    A new type of neutron detector, named Stack Structure Solid organic Scintillator (S4), consisting of multi-layer plastic scintillators with capability to suppress low-energy γ rays under high-counting rate has been constructed and tested. To achieve n- γ discrimination, we exploit the difference in the ranges of the secondary charged particles produced by the interactions of neutrons and γ rays in the scintillator material. The thickness of a plastic scintillator layer was determined based on the results of Monte Carlo simulations using the Geant4 toolkit. With layer thicknesses of 5 mm, we have achieved a good separation between neutrons and γ rays at 5 MeVee threshold setting. We have also determined the detection efficiencies using monoenergetic neutrons at two energies produced by the d + d → n+3He reaction. The results agree well with the Geant4 simulations implementing the Li e ̀ge Intranuclear Cascade hadronic model (INCL++) and the high-precision model of low-energy neutron interactions (NeutronHP).

  8. Miniaturized time-resolved Raman spectrometer for planetary science based on a fast single photon avalanche diode detector array.

    Science.gov (United States)

    Blacksberg, Jordana; Alerstam, Erik; Maruyama, Yuki; Cochrane, Corey J; Rossman, George R

    2016-02-01

    We present recent developments in time-resolved Raman spectroscopy instrumentation and measurement techniques for in situ planetary surface exploration, leading to improved performance and identification of minerals and organics. The time-resolved Raman spectrometer uses a 532 nm pulsed microchip laser source synchronized with a single photon avalanche diode array to achieve sub-nanosecond time resolution. This instrument can detect Raman spectral signatures from a wide variety of minerals and organics relevant to planetary science while eliminating pervasive background interference caused by fluorescence. We present an overview of the instrument design and operation and demonstrate high signal-to-noise ratio Raman spectra for several relevant samples of sulfates, clays, and polycyclic aromatic hydrocarbons. Finally, we present an instrument design suitable for operation on a rover or lander and discuss future directions that promise great advancement in capability.

  9. Boosted Supercapacitive Energy with High Rate Capability of aCarbon Framework with Hierarchical Pore Structure in an Ionic Liquid.

    Science.gov (United States)

    Wang, Xuehang; Zhou, Haitao; Lou, Fengliu; Li, Yahao; Buan, Marthe E M; Duan, Xuezhi; Walmsley, John C; Sheridan, Edel; Chen, De

    2016-11-09

    The specific energy of a supercapacitor (SC) with an ionic liquid (IL)-based electrolyte is larger than that using an aqueous electrolyte owing to the wide operating voltage window provided by the IL. However, the wide-scale application of high-energy SCs using ILs is limited owing to a serious reduction of the energy with increasing power. The introduction of macropores to the porous material can mitigate the reduction in the gravimetric capacitance at high rates, but this lowers the volumetric capacitance. Synthetic polymers can be used to obtain macroporous frameworks with high apparent densities, but the preservation of the frameworks during activation is challenging. To simultaneously achieve high gravimetric capacitance, volumetric capacitance, and rate capability, a systematic strategy was used to synthesize a densely knitted carbon framework with a hierarchical pore structure by using a polymer. The energy of the SC using the hierarchically porous carbon was 160 Wh kg(-1) and 85 Wh L(-1) on an active material base at a power of 100 W kg(-1) in an IL electrolyte, and 60 % of the energy was still retained at a power larger than 5000 W kg(-1) . To illustrate, a full-packaged SC with the material could store/release energy comparable to a Ni-metal hydride battery (gravimetrically) and one order of magnitude higher than a commercial carbon-based SC (volumetrically), within one minute. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Probing temperature gradients within the GaN buffer layer of AlGaN/GaN high electron mobility transistors with Raman thermography

    Energy Technology Data Exchange (ETDEWEB)

    Hodges, C., E-mail: chris.hodges@bristol.ac.uk; Pomeroy, J.; Kuball, M. [H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

    2014-02-14

    We demonstrate the ability of confocal Raman thermography using a spatial filter and azimuthal polarization to probe vertical temperature gradients within the GaN buffer layer of operating AlGaN/GaN high electron mobility transistors. Temperature gradients in the GaN layer are measured by using offset focal planes to minimize the contribution from different regions of the GaN buffer. The measured temperature gradient is in good agreement with a thermal simulation treating the GaN thermal conductivity as homogeneous throughout the layer and including a low thermal conductivity nucleation layer to model the heat flow between the buffer and substrate.

  11. Raman scattering and x-ray diffraction studies of polycrystalline CaCu3Ti4O12 under high-pressure

    DEFF Research Database (Denmark)

    Valim, D.; Filho, A. G. S.; Freire, P. T. C.

    2004-01-01

    remains stable up to the maximum pressure (5.3 GPa) we reached in this experiment. The pressure coefficients for the observed Raman modes were determined. This set of parameters was used for evaluating the stress developed in CCTO thin films. The high-pressure x-ray studies were extended up to 46 GPa...... and the data confirmed that the T-h structure remains stable up to this pressure. The pressure-volume data are well described by the Birch's equation of state. The experimental value of the zero pressure bulk modulus is B-0=212+/-2 GPa. Gruneisen parameters of CCTO were also determined....

  12. Lidar observations of tropical high-altitude cirrus clouds: results from dual-wavelength Raman lidar measurements during the ALBATROSS campaign 1996

    Science.gov (United States)

    Beyerle, Georg; Schaefer, H. J.; Schrems, Otto; Neuber, R.; Rairoux, P.; McDermid, I. S.

    1997-05-01

    Results from dual wavelength Raman lidar observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus clouds were present in more than 50% of the observations at latitudes between 23.5 degrees south and 23.5 degrees north and altitudes between 11 and 16 km. Volume depolarization is found to be a sensitive parameter for the detection of subvisible cloud layers. Using Mie scattering calculations estimates of the ice water content are derived.

  13. Multiwavelength Raman fiber ring laser with the spectrum profile broadened by parametric four wave mixing in highly nonlinear dispersion-shifted fibers

    Institute of Scientific and Technical Information of China (English)

    Yan Wang; Qing Wang; Wei Zhang; Xiaoming Liu; Jiangde Peng

    2005-01-01

    @@ A broadband multiwavelength Raman fiber ring laser (RFRL) covering the whole C-band at room temperature are presented. The effect of the intracavity highly nonlinear dispersion-shifted fiber on broadening and flattening the output spectrum envelope is discussed and experimentally demonstrated. More than 45-dB extinction-ratio multiwavelength output from 1527.76 to 1566.86 nm with 100-GHz channel spacing and 2.1-dB power ripple has been achieved by carefully controlling the individual powers of three pump lasers.

  14. Well-organized raspberry-like Ag@Cu bimetal nanoparticles for highly reliable and reproducible surface-enhanced Raman scattering

    Science.gov (United States)

    Lee, Jung-Pil; Chen, Dongchang; Li, Xiaxi; Yoo, Seungmin; Bottomley, Lawrence A.; El-Sayed, Mostafa A.; Park, Soojin; Liu, Meilin

    2013-11-01

    Surface-enhanced Raman scattering (SERS) is ideally suited for probing and mapping surface species and incipient phases on fuel cell electrodes because of its high sensitivity and surface-selectivity, potentially offering insights into the mechanisms of chemical and energy transformation processes. In particular, bimetal nanostructures of coinage metals (Au, Ag, and Cu) have attracted much attention as SERS-active agents due to their distinctive electromagnetic field enhancements originated from surface plasmon resonance. Here we report excellent SERS-active, raspberry-like nanostructures composed of a silver (Ag) nanoparticle core decorated with smaller copper (Cu) nanoparticles, which displayed enhanced and broadened UV-Vis absorption spectra. These unique Ag@Cu raspberry nanostructures enable us to use blue, green, and red light as the excitation laser source for surface-enhanced Raman spectroscopy (SERS) with a large enhancement factor (EF). A highly reliable SERS effect was demonstrated using Rhodamine 6G (R6G) molecules and a thin film of gadolinium doped ceria.Surface-enhanced Raman scattering (SERS) is ideally suited for probing and mapping surface species and incipient phases on fuel cell electrodes because of its high sensitivity and surface-selectivity, potentially offering insights into the mechanisms of chemical and energy transformation processes. In particular, bimetal nanostructures of coinage metals (Au, Ag, and Cu) have attracted much attention as SERS-active agents due to their distinctive electromagnetic field enhancements originated from surface plasmon resonance. Here we report excellent SERS-active, raspberry-like nanostructures composed of a silver (Ag) nanoparticle core decorated with smaller copper (Cu) nanoparticles, which displayed enhanced and broadened UV-Vis absorption spectra. These unique Ag@Cu raspberry nanostructures enable us to use blue, green, and red light as the excitation laser source for surface-enhanced Raman spectroscopy

  15. Noninvasive analysis of thin turbid layers using microscale spatially offset Raman spectroscopy.

    Science.gov (United States)

    Conti, Claudia; Realini, Marco; Colombo, Chiara; Sowoidnich, Kay; Afseth, Nils Kristian; Bertasa, Moira; Botteon, Alessandra; Matousek, Pavel

    2015-06-01

    Here, we demonstrate, for the first time, the extension of applicability of recently developed microscale spatially offset Raman spectroscopy (SORS), micro-SORS, from the area of cultural heritage to a wider range of analytical problems involving thin, tens of micrometers thick diffusely scattering turbid layers. The method can be applied in situations where a high turbidity of layers prevents the deployment of conventional confocal Raman microscopy with its depth resolving capability. The method was applied successfully to detect noninvasively the presence of thin, highly turbid layers within polymers, wheat seeds, and paper. An invasive, cross sectional analysis confirmed the micro-SORS findings. Micro-SORS represents a new Raman imaging modality expanding the portfolio of noninvasive, chemically specific analytical tools.

  16. Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells

    Energy Technology Data Exchange (ETDEWEB)

    Brückner, Michael [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Becker, Katja [Justus Liebig University Giessen, Biochemistry and Molecular Biology, 35392 Giessen (Germany); Popp, Jürgen [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Friedrich Schiller University Jena, Institute for Physical Chemistry, 07745 Jena (Germany); Friedrich Schiller University Jena, Abbe Centre of Photonics, 07745 Jena (Germany); Frosch, Torsten, E-mail: torsten.frosch@uni-jena.de [Leibniz Institute of Photonic Technology, 07745 Jena (Germany); Friedrich Schiller University Jena, Institute for Physical Chemistry, 07745 Jena (Germany); Friedrich Schiller University Jena, Abbe Centre of Photonics, 07745 Jena (Germany)

    2015-09-24

    A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples. The Gaussian-like intensity distribution of the illuminating laser beam is shaped by a square-core optical multimode fiber to a top-hat profile with very homogeneous intensity distribution to fulfill the conditions of Koehler. The 30 m long optical fiber and an additional vibrator efficiently destroy the polarization and coherence of the illuminating light. This homogeneous, incoherent illumination is an essential prerequisite for stable quantitative imaging of complex biological samples. The fiber array translates the two-dimensional lateral information of the Raman stray light into separated spectral channels with very high contrast. The Raman image can be correlated with a corresponding white light microscopic image of the sample. The new setup enables simultaneous quantification of all Raman spectra across the whole spatial area with very good spectral resolution and thus outperforms other Raman imaging approaches based on scanning and tunable filters. The unique capabilities of the setup for fast, gentle, sensitive, and selective chemical imaging of biological samples were applied for automated hemozoin analysis. A special algorithm was developed to generate Raman images based on the hemozoin distribution in red blood cells without any influence from other Raman scattering. The new imaging setup in combination with the robust algorithm provides a novel, elegant way for chemical selective analysis of the malaria pigment hemozoin in early ring stages of Plasmodium falciparum infected erythrocytes. - Highlights: • Raman hyperspectral imaging allows for chemical selective analysis of biological samples with spatial heterogeneity. • A homogeneous, incoherent illumination is essential for reliable

  17. Raman Spectroscopy and Related Techniques in Biomedicine

    Directory of Open Access Journals (Sweden)

    Alistair Elfick

    2010-03-01

    Full Text Available In this review we describe label-free optical spectroscopy techniques which are able to non-invasively measure the (biochemistry in biological systems. Raman spectroscopy uses visible or near-infrared light to measure a spectrum of vibrational bonds in seconds. Coherent anti-Stokes Raman (CARS microscopy and stimulated Raman loss (SRL microscopy are orders of magnitude more efficient than Raman spectroscopy, and are able to acquire high quality chemically-specific images in seconds. We discuss the benefits and limitations of all techniques, with particular emphasis on applications in biomedicine—both in vivo (using fiber endoscopes and in vitro (in optical microscopes.

  18. Discrimination of bladder cancer cells from normal urothelial cells with high specificity and sensitivity: combined application of atomic force microscopy and modulated Raman spectroscopy.

    Science.gov (United States)

    Canetta, Elisabetta; Riches, Andrew; Borger, Eva; Herrington, Simon; Dholakia, Kishan; Adya, Ashok K

    2014-05-01

    Atomic force microscopy (AFM) and modulated Raman spectroscopy (MRS) were used to discriminate between living normal human urothelial cells (SV-HUC-1) and bladder tumour cells (MGH-U1) with high specificity and sensitivity. MGH-U1 cells were 1.5-fold smaller, 1.7-fold thicker and 1.4-fold rougher than normal SV-HUC-1 cells. The adhesion energy was 2.6-fold higher in the MGH-U1 cells compared to normal SV-HUC-1 cells, which possibly indicates that bladder tumour cells are more deformable than normal cells. The elastic modulus of MGH-U1 cells was 12-fold lower than SV-HUC-1 cells, suggesting a higher elasticity of the bladder cancer cell membranes. The biochemical fingerprints of cancer cells displayed a higher DNA and lipid content, probably due to an increase in the nuclear to cytoplasm ratio. Normal cells were characterized by higher protein contents. AFM studies revealed a decrease in the lateral dimensions and an increase in thickness of cancer cells compared to normal cells; these studies authenticate the observations from MRS. Nanostructural, nanomechanical and biochemical profiles of bladder cells provide qualitative and quantitative markers to differentiate between normal and cancerous cells at the single cellular level. AFM and MRS allow discrimination between adhesion energy, elasticity and Raman spectra of SV-HUC-1 and MGH-U1 cells with high specificity (83, 98 and 95%) and sensitivity (97, 93 and 98%). Such single-cell-level studies could have a pivotal impact on the development of AFM-Raman combined methodologies for cancer profiling and screening with translational significance.

  19. Achieving high capacity and rate capability in layered lithium transition metal oxide cathodes for lithium-ion batteries

    Science.gov (United States)

    Ahn, Juhyeon; Susanto, Dieky; Noh, Jae-Kyo; Ali, Ghulam; Cho, Byung Won; Chung, Kyung Yoon; Kim, Jong Hak; Oh, Si Hyoung

    2017-08-01

    In this study, we target to find a new composition for a layered mixed metal oxide, which has a high structural stability and a good electrochemical performance. Our strategy is to alter the transition metal composition focusing on the relative amounts of redox active Ni and Co to the inactive Mn, based on highly-stabilized LiNi1/3Co1/3Mn1/3O2. X-ray absorption near-edge structure and X-ray diffraction analyses show that the degree of cation disorder decreases on increasing the ratio of Ni and Co to Mn, by the presence of Ni3+, suggesting that slightly higher Ni and Co contents lead to improved structural stability. Electrochemical studies demonstrate that LiNi0.4Co0.4Mn0.2O2 cathodes exhibit considerable improvements in both the reversible capacity and the rate capabilities at a voltage range of 2.5-4.6 V. In situ XRD measurements reveal that LiNi0.4Co0.4Mn0.2O2 maintains a single-phase and undergoes lesser structural variations compared to controlled compositions during a delithiation process up to 4.6 V, while achieving a high reversible capacity over 200 mAh g-1. As a result, LiNi0.4Co0.4Mn0.2O2 experiences fewer structural degradations during electrochemical cycling, which explains the excellent long-term cycling performance.

  20. Bio-inspired 2-line ferrihydrite as a high-capacity and high-rate-capability anode material for lithium-ion batteries

    Science.gov (United States)

    Hashimoto, Hideki; Ukita, Masahiro; Sakuma, Ryo; Nakanishi, Makoto; Fujii, Tatsuo; Imanishi, Nobuyuki; Takada, Jun

    2016-10-01

    A high-capacity and high-rate-capability anode material for lithium-ion batteries, silicon-doped iron oxyhydroxide or 2-line ferrihydrite (2Fh), was prepared by mixing iron nitrate powder, tetraethyl orthosilicate, 2-propanol, and ammonium hydrogen carbonate powder at room temperature. The design of this material was inspired by a bacteriogenic product, a nanometric amorphous iron-based oxide material containing small amounts of structural Si. The atomistic structure of the prepared Si-doped 2Fh was strongly affected by the Si molar ratio [x = Si/(Fe + Si)]. Its crystallinity gradually decreased as the Si molar ratio increased, with a structural variation from nanocrystalline to amorphous at x = 0.25. The sample with x = 0.20 demonstrated the best Li storage performance. The developed material exhibited a high capacity of ∼400 mAh g-1 at the 25th cycle in the voltage range of 0.3-3.0 V and at a current rate of 9 A g-1, which was three times greater than that of the Si-free 2Fh. This indicates that Si-doping into the 2Fh structure realizes good rate capability, which are presumably because of the specific nanocomposite structure of iron-based electrochemical centers embedded in the Si-based amorphous matrix, generated by reversible Li insertion/deinsertion process.

  1. Broadband stimulated Raman spectroscopy in the deep ultraviolet region

    Science.gov (United States)

    Kuramochi, Hikaru; Fujisawa, Tomotsumi; Takeuchi, Satoshi; Tahara, Tahei

    2017-09-01

    We report broadband stimulated Raman measurements in the deep ultraviolet (DUV) region, which enables selective probing of the aromatic amino acid residues inside proteins through the resonance enhancement. We combine the narrowband DUV Raman pump pulse (1000 cm-1) to realize stimulated Raman measurements covering a >1500 cm-1 spectral window. The stimulated Raman measurements for neat solvents, tryptophan, tyrosine, and glucose oxidase are performed using 240- and 290-nm Raman pump, highlighting the high potential of the DUV stimulated Raman probe for femtosecond time-resolved study of proteins.

  2. Tip-enhanced Raman spectroscopy: From concepts to practical applications

    Science.gov (United States)

    Jiang, Nan; Kurouski, Dmitry; Pozzi, Eric A.; Chiang, Naihao; Hersam, Mark C.; Van Duyne, Richard P.

    2016-08-01

    Tip-enhanced Raman spectroscopy (TERS) is a powerful technique that integrates the vibrational fingerprinting of Raman spectroscopy and the sub-nanometer resolution of scanning probe microscopy (SPM). As a result, TERS is capable of obtaining chemical maps of analyzed specimens with exceptional lateral resolution. This is extremely valuable for the study of interactions between molecules and substrates, in addition to structural characterization of biological objects, such as viruses and amyloid fibrils, 2D polymeric materials, and monitoring electrochemical and photo-catalytic processes. In this mini-review, we discuss the most significant advances of TERS, including: super high resolution chemical imaging, monitoring of catalytic processes, incorporation of pulsed-excitation techniques, single-site electrochemistry, biosensing, and art conservation. We begin with a short overview of TERS, comparing it with other surface analytical techniques, followed by an overview of recent developments and future applications in TERS.

  3. Amniotic mesenchymal stem cells enhance wound healing in diabetic NOD/SCID mice through high angiogenic and engraftment capabilities.

    Directory of Open Access Journals (Sweden)

    Sung-Whan Kim

    Full Text Available Although human amniotic mesenchymal stem cells (AMMs have been recognised as a promising stem cell resource, their therapeutic potential for wound healing has not been widely investigated. In this study, we evaluated the therapeutic potential of AMMs using a diabetic mouse wound model. Quantitative real-time PCR and ELISA results revealed that the angiogenic factors, IGF-1, EGF and IL-8 were markedly upregulated in AMMs when compared with adipose-derived mesenchymal stem cells (ADMs and dermal fibroblasts. In vitro scratch wound assays also showed that AMM-derived conditioned media (CM significantly accelerated wound closure. Diabetic mice were generated using streptozotocin and wounds were created by skin excision, followed by AMM transplantation. AMM transplantation significantly promoted wound healing and increased re-epithelialization and cellularity. Notably, transplanted AMMs exhibited high engraftment rates and expressed keratinocyte-specific proteins and cytokeratin in the wound area, indicating a direct contribution to cutaneous closure. Taken together, these data suggest that AMMs possess considerable therapeutic potential for chronic wounds through the secretion of angiogenic factors and enhanced engraftment/differentiation capabilities.

  4. Effect of vitamin E suplementation on the health status and production capabilities of high producing diary cows

    Directory of Open Access Journals (Sweden)

    Cilev Goce

    2003-01-01

    Full Text Available Concerning the importance of vitamin E in the nutrition of high-producing cows, a review of the recent available literature was done (for its chemical characteristics, metabolism, content in the feedstuffs and the effects of its use upon the cows health status and production capabilities. As a result of the achieved knowledge for the vitamin E role in the cows nutrition, new norms were worked out. The values of these norms are connected to the cows' production phase and they are as follows: 1000 mg/day - from the drying period (60-70 days before calving to 3rd week before calving; 3000 mg/day - 3 weeks before and 4 weeks after calving (transition phase; 1000 mg/day - 5 to 10 weeks after calving; 500 mg/day - from the 11-th week of lactation until the drying period. The enlarged amount of vitamin E in the transition phase is important for the reduction of infective and metabilism diseases, i.e. it is important for the cows immunologic system. It decreases the risks connected to the mastitis appearance and improves the reproductive function as well.

  5. Beamline 9.3.2 - a high-resolution, bend-magnet beamline with circular polarization capability

    Energy Technology Data Exchange (ETDEWEB)

    Moler, E.J.; Hussain, Z.; Howells, M.R. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Beamline 9.3.2 is a high resolution, SGM beamline on an ALS bending magnet with access to photon energies from 30-1500 eV. Features include circular polarization capability, a rotating chamber platform that allows switching between experiments without breaking vacuum, an active feedback system that keeps the beam centered on the entrance slit of the monochromator, and a bendable refocusing mirror. The beamline optics consist of horizontally and vertically focussing mirrors, a Spherical Grating Monochromator (SGM) with movable entrance and exit slits, and a bendable refocussing mirror. In addition, a movable aperature has been installed just upstream of the vertically focussing mirror which can select the x-rays above or below the plane of the synchrotron storage ring, allowing the user to select circularly or linearly polarized light. Circularly polarized x-rays are used to study the magnetic properties of materials. Beamline 9.3.2 can supply left and right circularly polarized x-rays by a computer controlled aperture which may be placed above or below the plane of the synchrotron storage ring. The degree of linear and circular polarization has been measured and calibrated.

  6. In situ precise electrospinning of medical glue fibers as nonsuture dural repair with high sealing capability and flexibility

    Directory of Open Access Journals (Sweden)

    Lv FY

    2016-08-01

    Full Text Available Fu-Yan Lv,1,* Rui-Hua Dong,1,* Zhao-Jian Li,2,* Chong-Chong Qin,1 Xu Yan,1,3 Xiao-Xiao He,1 Yu Zhou,4 Shi-Ying Yan,1 Yun-Ze Long1,3 1Collaborative Innovation Center for Nanomaterials & Optoelectronic Devices, College of Physics, Qingdao University, 2Department of Neurosurgery, Affiliated Hospital of Qingdao University, 3Industrial Research Institute of Nonwovens & Technical Textiles, College of Textiles & Clothing, 4Medical College, Qingdao University, Qingdao, People’s Republic of China *These authors contributed equally to this work Purpose: In this work, we propose an in situ precise electrospinning of medical glue fibers onto dural wound for improving sealing capability, avoiding tissue adhesion, and saving time in dural repair.Methods: N-octyl-2-cyanoacrylate, a commercial tissue adhesive (medical glue, can be electrospun into ultrathin fibrous film with precise and homogeneous deposition by a gas-assisted electrospinning device.Results: The self-assembled N-octyl-2-cyanoacrylate film shows high compactness and flexibility owing to its fibrous structure. Simulation experiments on egg membranes and goat meninges demonstrated that this technology can repair small membrane defects quickly and efficiently.Conclusion: This method may have potential application in dural repair, for example, working as an effective supplementary technique for conventional dura suture. Keywords: cyanoacrylates, electrospun fibers, in situ repair dural, gas-assisted electrospinning apparatus

  7. Effects of substrate on 2D materials, graphene, MoS2, WS2, and black phosphorus, investigated by high temperature and spatially resolved Raman scattering and photoluminescence

    Science.gov (United States)

    Su, Liqin

    The exploration of a group of new 2D materials, such as graphene and transition metal dichalcogenides, has become the hottest research of interest in recent years. With the dependable techniques of producing 2D materials, particularly mechanical exfoliation and chemical vapor deposition, we are able to study all kinds of their unique properties in mechanical, electrical and optical fields. In this dissertation, we examine the vibrational and thermal properties of four 2D materials---graphene, MoS2, WS2 and black phosphorus---as well as their interaction with the supporting substrates, by using temperature-dependent Raman spectroscopy. Regarding the increasing interests of studying on the fabrication and applications of 2D materials, the role of 2D-material/substrate interaction has seldom been taken into consideration which would significantly affects the quality of the grown films and the performance of the devices. To the best of our knowledge, we are the first to systematically investigate on this issue. At first, we performed temperature-dependent Raman spectroscopy on two graphene samples prepared by CVD and ME up to 400°C, as well as graphite as a reference. The temperature dependence of both graphene samples shows very non-linear behavior for G and 2D bands, but with the CVD-grown graphene more nonlinear. Comparing to the Raman spectra collected before the measurements, the spectra after the measurements exhibit not only a shift of peak position but also a huge broadening of linewidth, especially for CVD-grown graphene. This study implies that the polymeric residues from either scotch tape or PMMA during transfer process are converted to amorphous carbon after annealed at high temperature, which may significantly change the optical and electrical properties of graphene. With the same temperature-dependent Raman technique as graphene, we examine on monolayer MoS2 and WS2, and thin-film black phosphorus and demonstrate that the film morphology and the

  8. Limitations of using Raman microscopy for the analysis of high-content-carbon-filled ethylene propylene diene monomer rubber

    DEFF Research Database (Denmark)

    Ghanbari-Siahkali, A.; Almdal, K.; Kingshott, P.

    2003-01-01

    on the sample, ranging from 4.55 mW to 0.09 mW. The surface of the EPDM was analyzed before and after laser exposure using X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The techniques have surface probe depths of approximately less......) analysis was also performed on the Raman analyzed areas to visually illustrate the effects created due to laser light exposure (i.e., burning marks). The change in surface chemistry also occurs in regions a few millimeters from the exposed sites, indicating that the effect is quite long range. However...

  9. Beyond optical molasses: 3D raman sideband cooling of atomic cesium to high phase-space density

    Science.gov (United States)

    Kerman; Vuletic; Chin; Chu

    2000-01-17

    We demonstrate a simple, general purpose method to cool neutral atoms. A sample containing 3x10(8) cesium atoms prepared in a magneto-optical trap is cooled and simultaneously spin polarized in 10 ms at a density of 1.1x10(11) cm (-3) to a phase space density nlambda(3)(dB) = 1/500, which is almost 3 orders of magnitude higher than attainable in free space with optical molasses. The technique is based on 3D degenerate Raman sideband cooling in optical lattices and remains efficient even at densities where the mean lattice site occupation is close to unity.

  10. Facile Hydrothermal Synthesis of VS2/Graphene Nanocomposites with Superior High-Rate Capability as Lithium-Ion Battery Cathodes.

    Science.gov (United States)

    Fang, Wenying; Zhao, Hongbin; Xie, Yanping; Fang, Jianhui; Xu, Jiaqiang; Chen, Zhongwei

    2015-06-17

    In this study, a facile one-pot process for the synthesis of hierarchical VS2/graphene nanosheets (VS2/GNS) composites based on the coincident interaction of VS2 and reduced graphene oxide (rGO) sheets in the presence of cetyltrimethylammonium bromide is developed for the first time. The nanocomposites possess a hierarchical structure of 50 nm VS2 sheets in thickness homogeneously anchored on graphene. The VS2/GNS nanocomposites exhibit an impressive high-rate capability and good cyclic stability as a cathode material for Li-ion batteries, which retain 89.3% of the initial capacity 180.1 mAh g(-1) after 200 cycles at 0.2 C. Even at 20 C, the composites still deliver a high capacity of 114.2 mAh g(-1) corresponding to 62% of the low-rate capacity. Expanded studies show that VS2/GNS, as an anode material, also has a good reversible performance with 528 mAh g(-1) capacity after 100 cycles at 200 mA g(-1). The excellent electrochemical performance of the composites for reversible Li+ storage should be attributed to the exceptional interaction between VS2 and GNS that enabled fast electron transport between graphene and VS2, facile Li-ion diffusion within the electrode. Moreover, GNS provides a topological and structural template for the nucleation and growth of two-dimensional VS2 nanosheets and acted as buffer matrix to relieve the volume expansion/contraction of VS2 during the electrochemical charge/discharge, facilitating improved cycling stability. The VS2/GNS composites may be promising electrode materials for the next generation of rechargeable lithium ion batteries.

  11. Evolution of a high local strain in rolling up MoS2 sheets decorated with Ag and Au nanoparticles for surface-enhanced Raman scattering

    Science.gov (United States)

    Hwang, Da Young; Hack Suh, Dong

    2017-01-01

    We report that a high local strain was obtained for multilayer MoS2 nanoscrolls decorated with noble nanoparticles (Ag and Au NPs) using a rolling process beyond breaking or slipping of MoS2. The local strain was estimated through the bending strain in the nanoscrolls and the extent of coverage of Ag and Au NPs decorated on MoS2, exhibiting magnified surface-enhanced Raman scattering. TEM images showed that the MoS2-Ag and MoS2-Au nanoscrolls have a tube-like morphology decorated with NPs on the inner and outer sides of the MoS2 nanoscrolls. In the Raman spectra, we confirmed the red shift and broadness of the FWHM for nanoscrolls in the eigenvectors of the {{{E}}}{2{{g}}+}1 and {{{E}}}{2g+}1 modes. From the Grüneisen parameter γ and the shear deformation potential β, we obtained peak shifts of ˜4.9 cm-1/% at {{{E}}}{2g-}1 and ˜1.1 cm-1/% strain at {{{E}}}{2g+}1 for free-standing MoS2. According to the obtained relationship of the Raman shift and the induced uniaxial tensile strain, the {{{E}}}{2g-}1 and {{{E}}}{2g+}1 peaks shifted upwards to around -12.8 cm-1 and -2.9 cm-1, respectively, and can be converted to an induced uniaxial tensile strain of about 2.6% for MoS2-Ag nanoscrolls.

  12. Developing university innovation capacity: how can innovation policy effectively harness universities? Capability to promote high-growth technology businesses?

    NARCIS (Netherlands)

    Rasmussen, Einar; Benneworth, Paul; Gulbrandsen, Magnus

    2013-01-01

    Some universities and departments have been very successful in stimulating university spin- off firms (USOs). This has persuaded policy makers and university administrators to devote considerable resources to improve universities' capabilities to promote USOs, but with little tangible results. Relat

  13. Developing university innovation capacity: how can innovation policy effectively harness universities? Capability to promote high-growth technology businesses?

    NARCIS (Netherlands)

    Rasmussen, Einar; Benneworth, Paul Stephen; Gulbrandsen, Magnus

    2013-01-01

    Some universities and departments have been very successful in stimulating university spin- off firms (USOs). This has persuaded policy makers and university administrators to devote considerable resources to improve universities' capabilities to promote USOs, but with little tangible results.

  14. Theoretical and numerical treatment of modal instability in high-power core and cladding-pumped Raman fiber amplifiers.

    Science.gov (United States)

    Naderi, Shadi; Dajani, Iyad; Grosek, Jacob; Madden, Timothy

    2016-07-25

    Raman fiber lasers have been proposed as potential candidates for scaling beyond the power limitations imposed on near diffraction-limited rare-earth doped fiber lasers. One limitation is the modal instability (MI) and we explore the physics of this phenomenon in Raman fiber amplifiers (RFAs). By utilizing the conservation of number of photons and conservation of energy in the absence of loss, the 3 × 3 governing system of nonlinear equations describing the pump and the signal modal content are decoupled and solved analytically for cladding-pumped RFAs. By comparing the extracted signal at MI threshold for the same step index-fiber, it is found that the MI threshold is independent of the length of the amplifier or whether the amplifier is co-pumped or counter-pumped; dictated by the integrated heat load along the length of fiber. We extend our treatment to gain-tailored RFAs and show that this approach is of limited utility in suppressing MI. Finally, we formulate the physics of MI in core-pumped RFAs where both pump and signal interferences participate in writing the time-dependent index of refraction grating.

  15. Development of high-sensitive, reproducible colloidal surface-enhanced Raman spectroscopy active substrate using silver nanocubes for potential biosensing applications

    Science.gov (United States)

    Hasna, Kudilatt; Lakshmi, Kiran; Ezhuthachan Jayaraj, Madambi Kunjukuttan; Kumar, Kumaran Rajeev; Matham, Murukeshan Vadakke

    2016-04-01

    Surface-enhanced Raman spectroscopy (SERS) has emerged as one of the thrust research areas that could find potential applications in bio and chemical sensing. We developed colloidal SERS active substrate with excellent sensitivity and high reproducibility using silver nanocube (AgNC) synthesized via the solvothermal method. Finite-difference time-domain simulation was carried out in detail to visualize dipole generation in the nanocube during localized surface plasmon resonance and to locate the respective hot spots in AgNC responsible for the huge Raman enhancement. The prediction is verified by the SERS analysis of the synthesized nanocubes using Rhodamine 6G molecule. An excellent sensitivity with a detection limit of 10-17 M and a very high enhancement factor of 1.2×108 confirms the "hot spots" in the nanocube. SERS activity is also carried out for crystal violet and for food adulterant Sudan I molecule. Finally, label-free DNA detection is performed to demonstrate the versatility of SERS as a potential biosensor.

  16. Estimation of free carrier concentrations in high-quality heavily doped GaN:Si micro-rods by photoluminescence and Raman spectroscopy

    Science.gov (United States)

    Mohajerani, M. S.; Khachadorian, S.; Nenstiel, C.; Schimpke, T.; Avramescu, A.; Strassburg, M.; Hoffmann, A.; Waag, A.

    2016-03-01

    The controlled growth of highly n-doped GaN micro rods is one of the major challenges in the fabrication of recently developed three-dimensional (3D) core-shell light emitting diodes (LEDs). In such structures with a large active area, higher electrical conductivity is needed to achieve higher current density. In this contribution, we introduce high quality heavily-doped GaN:Si micro-rods which are key elements of the newly developed 3D core-shell LEDs. These structures were grown by metal-organic vapor phase epitaxy (MOVPE) using selective area growth (SAG). We employed spatially resolved micro-Raman and micro-photoluminescence (PL) in order to directly determine a free-carrier concentration profile in individual GaN micro-rods. By Raman spectroscopy, we analyze the low-frequency branch of the longitudinal optical (LO)-phonon-plasmon coupled modes and estimate free carrier concentrations from ≍ 2.4 × 1019 cm-3 up to ≍ 1.5 × 1020 cm-3. Furthermore, free carrier concentrations are determined by estimating Fermi energy level from the near band edge emission measured by low-temperature PL. The results from both methods reveal a good consistency.

  17. Effects of Low Carbohydrate High Protein (LCHP) diet on atherosclerotic plaque phenotype in ApoE/LDLR-/- mice: FT-IR and Raman imaging.

    Science.gov (United States)

    Wrobel, T P; Marzec, K M; Chlopicki, S; Maślak, E; Jasztal, A; Franczyk-Żarów, M; Czyżyńska-Cichoń, I; Moszkowski, T; Kostogrys, R B; Baranska, M

    2015-09-22

    Low Carbohydrate High Protein (LCHP) diet displays pro-atherogenic effects, however, the exact mechanisms involved are still unclear. Here, with the use of vibrational imaging, such as Fourier transform infrared (FT-IR) and Raman (RS) spectroscopies, we characterize biochemical content of plaques in Brachiocephalic Arteries (BCA) from ApoE/LDLR(-/-) mice fed LCHP diet as compared to control, recomended by American Institute of Nutrition, AIN diet. FT-IR images were taken from 6-10 sections of BCA from each mice and were complemented with RS measurements with higher spatial resolution of chosen areas of plaque sections. In aortic plaques from LCHP fed ApoE/LDLR(-/-) mice, the content of cholesterol and cholesterol esters was increased, while that of proteins was decreased as evidenced by global FT-IR analysis. High resolution imaging by RS identified necrotic core/foam cells, lipids (including cholesterol crystals), calcium mineralization and fibrous cap. The decreased relative thickness of the outer fibrous cap and the presence of buried caps were prominent features of the plaques in ApoE/LDLR(-/-) mice fed LCHP diet. In conclusion, FT-IR and Raman-based imaging provided a complementary insight into the biochemical composition of the plaque suggesting that LCHP diet increased plaque cholesterol and cholesterol esters contents of atherosclerotic plaque, supporting the cholesterol-driven pathogenesis of LCHP-induced atherogenesis.

  18. High Spectral Resolution Infrared and Raman Lidar Observations for the ARM Program: Clear and Cloudy Sky Applications

    Energy Technology Data Exchange (ETDEWEB)

    Revercomb, Henry; Tobin, David; Knuteson, Robert; Borg, Lori; Moy, Leslie

    2009-06-17

    This grant began with the development of the Atmospheric Emitted Radiance Interferometer (AERI) for ARM. The AERI has provided highly accurate and reliable observations of downwelling spectral radiance (Knuteson et al. 2004a, 2004b) for application to radiative transfer, remote sensing of boundary layer temperature and water vapor, and cloud characterization. One of the major contributions of the ARM program has been its success in improving radiation calculation capabilities for models and remote sensing that evolved from the multi-year, clear-sky spectral radiance comparisons between AERI radiances and line-by-line calculations (Turner et al. 2004). This effort also spurred us to play a central role in improving the accuracy of water vapor measurements, again helping ARM lead the way in the community (Turner et al. 2003a, Revercomb et al. 2003). In order to add high-altitude downlooking AERI-like observations over the ARM sites, we began the development of an airborne AERI instrument that has become known as the Scanning High-resolution Interferometer Sounder (Scanning-HIS). This instrument has become an integral part of the ARM Unmanned Aerospace Vehicle (ARM-UAV) program. It provides both a cross-track mapping view of the earth and an uplooking view from the 12-15 km altitude of the Scaled Composites Proteus aircraft when flown over the ARM sites for IOPs. It has successfully participated in the first two legs of the “grand tour” of the ARM sites (SGP and NSA), resulting in a very good comparison with AIRS observations in 2002 and in an especially interesting data set from the arctic during the Mixed-Phase Cloud Experiment (M-PACE) in 2004.

  19. High Spectral Resolution Infrared and Raman Lidar Observations for the ARM Program: Clear and Cloudy Sky Applications

    Energy Technology Data Exchange (ETDEWEB)

    Revercomb, Henry; Tobin, David; Knuteson, Robert; Borg, Lori; Moy, Leslie

    2009-06-17

    This grant began with the development of the Atmospheric Emitted Radiance Interferometer (AERI) for ARM. The AERI has provided highly accurate and reliable observations of downwelling spectral radiance (Knuteson et al. 2004a, 2004b) for application to radiative transfer, remote sensing of boundary layer temperature and water vapor, and cloud characterization. One of the major contributions of the ARM program has been its success in improving radiation calculation capabilities for models and remote sensing that evolved from the multi-year, clear-sky spectral radiance comparisons between AERI radiances and line-by-line calculations (Turner et al. 2004). This effort also spurred us to play a central role in improving the accuracy of water vapor measurements, again helping ARM lead the way in the community (Turner et al. 2003a, Revercomb et al. 2003). In order to add high-altitude downlooking AERI-like observations over the ARM sites, we began the development of an airborne AERI instrument that has become known as the Scanning High-resolution Interferometer Sounder (Scanning-HIS). This instrument has become an integral part of the ARM Unmanned Aerospace Vehicle (ARM-UAV) program. It provides both a cross-track mapping view of the earth and an uplooking view from the 12-15 km altitude of the Scaled Composites Proteus aircraft when flown over the ARM sites for IOPs. It has successfully participated in the first two legs of the “grand tour” of the ARM sites (SGP and NSA), resulting in a very good comparison with AIRS observations in 2002 and in an especially interesting data set from the arctic during the Mixed-Phase Cloud Experiment (M-PACE) in 2004.

  20. Miniature standoff Raman probe for neurosurgical applications

    Science.gov (United States)

    Stevens, Oliver A. C.; Hutchings, Joanne; Gray, William; Vincent, Rosa Louise; Day, John C.

    2016-08-01

    Removal of intrinsic brain tumors is a delicate process, where a high degree of specificity is required to remove all of the tumor tissue without damaging healthy brain. The accuracy of this process can be greatly enhanced by intraoperative guidance. Optical biopsies using Raman spectroscopy are a minimally invasive and lower-cost alternative to current guidance methods. A miniature Raman probe for performing optical biopsies of human brain tissue is presented. The probe allows sampling inside a conventional stereotactic brain biopsy system: a needle of length 200 mm and inner diameter of 1.8 mm. By employing a miniature stand-off Raman design, the probe removes the need for any additional components to be inserted into the brain. Additionally, the probe achieves a very low internal silica background while maintaining good collection of Raman signal. To illustrate this, the probe is compared with a Raman probe that uses a pair of optical fibers for collection. The miniature stand-off Raman probe is shown to collect a comparable number of Raman scattered photons, but the Raman signal to background ratio is improved by a factor of five at Raman shifts below ˜500 cm-1. The probe's suitability for use on tissue is demonstrated by discriminating between different types of healthy porcine brain tissue.

  1. Hyper-Raman spectroscopy of Earth related materials

    Science.gov (United States)

    Hellwig, H.

    2004-12-01

    Raman and infrared spectroscopy proved extremely successful in obtaining structural information and thermodynamic data on samples under high pressure conditions in a diamond anvil cell [1,2]. With substantial advances in CCD detector technology and the possibility to focus visible laser light down to several microns, Raman spectroscopy can nowadays be regarded one of the standard techniques for diamond anvil cell investigations. Nevertheless, Raman scattering suffers from often strong fluorescence and the strong Raman signal of the diamonds. Infrared spectroscopy is limited by the sample size and the diffraction limit of mid- or far-infrared radiation. With increasing pressure, diamonds also show strong infrared activity, which can interfere with the signal from the sample. Detectors in the mid- and far-infrared are inherently noisy, often leading to low signal-to-noise ratios for infrared measurements. With new techniques and instrumentation available, such as low noise CCD cameras and stable diode-pumped solid state laser systems, more demanding techniques become feasible as well. Especially hyper-Raman scattering, a nonlinear optical variant of infrared spectroscopy, can be used on a more routine basis for the first time. Pioneering work in the 70s and 80s have explored some of the capabilities of Hyper-Raman spectroscopy [3]. Unlike infrared spectroscopy, Hyper-Raman is not limited by the diffraction limit of mid- or far-infrared radiation, typically restricting the lower frequency limit to several hundred wave numbers. The major advantages of hyper-Raman are essentially background free spectra and the use of wavelengths in the near-infrared and visible, making possible micro focusing and taking advantage of high efficiencies, low noise, and smooth wavelength dependencies of CCD detectors. Hyper-Raman does not suffer from saturation caused by strong absorption in the infrared and is therefore less sensitive to surface effects. For centrosymmetric materials

  2. Surface-enhanced Raman spectroscopy on a surface plasmon resonance biosensor platform for gene diagnostics

    Science.gov (United States)

    Yuan, W.; Ho, H. P.; Suen, Y. K.; Kong, S. K.; Lin, Chinlon; Prasad, Paras N.; Li, J.; Ong, Daniel H. C.

    2008-02-01

    We propose to integrate the surface-enhanced Raman spectroscopy (SERS) detection capability with a surface plasmon resonance (SPR) biosensor platform. As a demonstration setup, the experimental scheme is built from a Total Internal Reflection Fluorescence (TIRF) microscope. The sample surface is a gold-coated plasmonic crystal substrate. Two oligonucleotide (ODN) probes that have been labeled with two different Raman active dyes are used to achieve a sandwich assay of target ODNs or polynucleotide. Upon complementary hybridizations between the target and probe ODNs, the target can be identified by detecting the narrow-band spectroscopic fingerprints of the Raman tags. This concept has high potential for achieving multiplexed detection of ODN targets because a very large number of probes can be incorporated to the plasmonic crystal substrate, which may find applications in gene based diseases diagnostics. We also explored the detection of single molecules and achieved some preliminary results.

  3. Femtosecond time-resolved impulsive stimulated Raman spectroscopy using sub-7-fs pulses: Apparatus and applications

    Science.gov (United States)

    Kuramochi, Hikaru; Takeuchi, Satoshi; Tahara, Tahei

    2016-04-01

    We describe details of the setup for time-resolved impulsive stimulated Raman spectroscopy (TR-ISRS). In this method, snapshot molecular vibrational spectra of the photoreaction transients are captured via time-domain Raman probing using ultrashort pulses. Our instrument features transform-limited sub-7-fs pulses to impulsively excite and probe coherent nuclear wavepacket motions, allowing us to observe vibrational fingerprints of transient species from the terahertz to 3000-cm-1 region with high sensitivity. Key optical components for the best spectroscopic performance are discussed. The TR-ISRS measurements for the excited states of diphenylacetylene in cyclohexane are demonstrated, highlighting the capability of our setup to track femtosecond dynamics of all the Raman-active fundamental molecular vibrations.

  4. Detection of single bacteria - causative agents of meningitis using raman microscopy

    Science.gov (United States)

    Baikova, T. V.; Minaeva, S. A.; Sundukov, A. V.; Svistunova, T. S.; Bagratashvili, V. N.; Alushin, M. V.; Gonchukov, S. A.

    2015-03-01

    Early diagnostics of meningitis is a very topical problem as it is a fulminant disease with a high level of mortality. The progress of this disease is, as a rule, accompanied by the appearance of bacteria in the cerebrospinal fluid (CSF) composition. The examination of the CSF is well known to be the only reliable approach to the identification of meningitis. However, the traditional biochemical analyses are time consuming and not always reliable, simple, and inexpensive, whereas the optical methods are poorly developed. This work is devoted to the study of Raman spectra of several bacterial cultures which are mainly present during meningitis. Raman microscopy is a prompt and noninvasive technique capable of providing reliable information about molecular-level alterations of biological objects at their minimal quantity and size. It was shown that there are characteristic lines in Raman spectra which can be the reliable markers for determination of bacterial form of meningitis at a level of a single bacterium.

  5. Ultraviolet Resonant Raman Enhancements in the Detection of Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Short Jr., Billy Joe [Naval Postgraduate School, Monterey, CA (United States)

    2009-06-01

    Raman-based spectroscopy is potentially militarily useful for standoff detection of high explosives. Normal (non-resonance) and resonance Raman spectroscopies are both light scattering techniques that use a laser to measure the vibrational spectrum of a sample. In resonance Raman, the laser is tuned to match the wavelength of a strong electronic absorbance in the molecule of interest, whereas, in normal Raman the laser is not tuned to any strong electronic absorbance bands. The selection of appropriate excitation wavelengths in resonance Raman can result in a dramatic increase in the Raman scattering efficiency of select band(s) associated with the electronic transition. Other than the excitation wavelength, however, resonance Raman is performed experimentally the same as normal Raman. In these studies, normal and resonance Raman spectral signatures of select solid high explosive (HE) samples and explosive precursors were collected at 785 nm, 244 nm and 229 nm. Solutions of PETN, TNT, and explosive precursors (DNT & PNT) in acetonitrile solvent as an internal Raman standard were quantitatively evaluated using ultraviolet resonance Raman (UVRR) microscopy and normal Raman spectroscopy as a function of power and select excitation wavelengths. Use of an internal standard allowed resonance enhancements to be estimated at 229 nm and 244 nm. Investigations demonstrated that UVRR provided ~2000-fold enhancement at 244 nm and ~800-fold improvement at 229 nm while PETN showed a maximum of ~25-fold at 244 nm and ~190-fold enhancement at 229 nm solely from resonance effects when compared to normal Raman measurements. In addition to the observed resonance enhancements, additional Raman signal enhancements are obtained with ultraviolet excitation (i.e., Raman scattering scales as !4 for measurements based on scattered photons). A model, based partly on the resonance Raman enhancement results for HE solutions, is presented for estimating Raman enhancements for solid HE samples.

  6. Raman spectroscopic measurements of CO2 density: Experimental calibration with high-pressure optical cell (HPOC) and fused silica capillary capsule (FSCC) with application to fluid inclusion observations

    Science.gov (United States)

    Wang, X.; Chou, I.-Ming; Hu, W.; Burruss, R.C.; Sun, Q.; Song, Y.

    2011-01-01

    Raman spectroscopy is a powerful method for the determination of CO2 densities in fluid inclusions, especially for those with small size and/or low fluid density. The relationship between CO2 Fermi diad split (??, cm-1) and CO2 density (??, g/cm3) has been documented by several previous studies. However, significant discrepancies exist among these studies mainly because of inconsistent calibration procedures and lack of measurements for CO2 fluids having densities between 0.21 and 0.75g/cm3, where liquid and vapor phases coexist near room temperature.In this study, a high-pressure optical cell and fused silica capillary capsules were used to prepare pure CO2 samples with densities between 0.0472 and 1.0060g/cm3. The measured CO2 Fermi diad splits were calibrated with two well established Raman bands of benzonitrile at 1192.6 and 1598.9cm-1. The relationship between the CO2 Fermi diad split and density can be represented by: ??=47513.64243-1374.824414????+13.25586152????2-0.04258891551????3 (r2=0.99835, ??=0.0253g/cm3), and this relationship was tested by synthetic fluid inclusions and natural CO2-rich fluid inclusions. The effects of temperature and the presence of H2O and CH4 on this relationship were also examined. ?? 2011 Elsevier Ltd.

  7. In-Situ Studies of Structure Transformation and Al Coordination of KAl(MoO42 during Heating by High Temperature Raman and 27Al NMR Spectroscopies

    Directory of Open Access Journals (Sweden)

    Min Wang

    2017-03-01

    Full Text Available Recent interest in optimizing composition and synthesis conditions of functional crystals, and the further exploration of new possible candidates for tunable solid-state lasers, has led to significant research on compounds in this family MIMIII(MVIO42 (MI = alkali metal, MIII = Al, In, Sc, Fe, Bi, lanthanide; MVI = Mo, W. The vibrational modes, structure transformation, and Al coordination of crystalline, glassy, and molten states of KAl(MoO42 have been investigated by in-situ high temperature Raman scattering and 27Al magic angle spinning nuclear magnetic resonance (MAS NMR spectroscopy, together with first principles density functional simulation of room temperature Raman spectrum. The results showed that, under the present fast quenching conditions, Al is present predominantly in [AlO6] octahedra in both KAl(MoO42 glass and melt, with the tetrahedrally coordinated Al being minor at approximately 2.7%. The effect of K+, from ordered arrangement in the crystal to random distribution in the melt, on the local chemical environment of Al, was also revealed. The distribution and quantitative analysis of different Al coordination subspecies are final discussed and found to be dependent on the thermal history of the glass samples.

  8. Highly sensitive on-site detection of drugs adulterated in botanical dietary supplements using thin layer chromatography combined with dynamic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Fang, Fang; Qi, Yunpeng; Lu, Feng; Yang, Liangbao

    2016-01-01

    The phenomenon of botanical dietary supplements (BDS) doped with illegal adulterants has become a serious problem all over the world, which could cause great threat to human's health. Therefore, it is of great value to identify BDS. Herein, we put forward a highly sensitive method for on-site detection of antitussive and antiasthmatic drugs adulterated in BDS using thin layer chromatography (TLC) combined with dynamic surface enhanced Raman spectroscopy (DSERS). Adulterants in BDS were separated on a TLC plate and located under UV illumination. Then DSERS detection was performed using a portable Raman spectrometer with 50% glycerol silver colloid serving as DSERS active substrate. Here, the effects of different solvents on detection efficacy were evaluated using phenformin hydrochloride (PHE) as a probe. It was shown that 50% glycerol resulted in higher SERS enhancement and relatively higher stability. Moreover, practical application of this novel TLC-DSERS method was demonstrated with rapid analysis of real BDS samples and one sample adulterated with benproperine phosphate (BEN) was found. Furthermore, the obtained result was verified by ultra performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF/MS). The sensitivity of the TLC-DSERS technique is 1-2 orders of magnitude higher than that of TLC-SERS technique. The results turned out that this combined method would have good prospects for on-site and sensitive detection of adulterated BDS. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Non-Complexing Anions for Quantitative Speciation Studies Using Raman Spectroscopy in Fused Silica High-Pressure Optical Cells Under Hydrothermal Conditions.

    Science.gov (United States)

    Applegarth, Lucas M S G A; Alcorn, Christopher; Bissonette, Katherine; Noël, John; Tremaine, Peter R

    2015-08-01

    This paper reports methods for obtaining time-dependent reduced isotropic Raman spectra of aqueous species in quartz capillary high-pressure optical cells under hydrothermal conditions, as a means of determining quantitative speciation in hydrothermal fluids. The methods have been used to determine relative Raman scattering coefficients and to examine the thermal decomposition kinetics of the non-complexing anions bisulfate (HSO4(-)), perchlorate (CIO4(-)), perrhenate (ReO4(-)), and trifluoromethanesulfonate, or "triflate" (CF3SO3(-)) in acidic and neutral solutions at temperatures up to 400°C and 30 MPa. Arrhenius expressions for calculating the thermal decomposition rate constants are also reported. Thermal stabilities in the acidic solutions followed the order HSO4(-) (stable) > ReO4(-) > CIO4(-) > CF3SO3(-), with half-lives (t1/2) > 7 h at 300°C. In neutral solutions, the order was HSO4(-) (stable) > CF3SO3(-) > ReO4(-) > CIO4(-), with t1/2 > 8 h at 350°C. CF3SO3(-) was extremely stable in neutral solutions, with t1/2 > 11 h at 400°C.

  10. High Surface-Enhanced Raman Scattering (SERS) Amplification Factor Obtained with Silver Printed Circuit Boards and the Influence of Phenolic Resins for the Characterization of the Pesticide Thiram.

    Science.gov (United States)

    Silva de Almeida, Francylaine; Bussler, Larissa; Marcio Lima, Sandro; Fiorucci, Antonio Rogério; da Cunha Andrade, Luis Humberto

    2016-07-01

    In this work, low-cost substrates with rough silver surfaces were prepared from commercial copper foil-covered phenolic board (CPB) and an aqueous solution of AgNO3, and were used for surface-enhanced Raman scattering (SERS) and surface-enhanced resonance Raman scattering (SERRS) measurements. A maximum SERS amplification factor of 1.2 × 10(7) was obtained for Rhodamine 6G (R6G), and use of the CPB resulted in a detection limit for Thiram pesticide of 0.5 µmol L(-1) The minimum detection level was limited by residual traces of phenolic groups that originated from the substrate resin, which became solubilized in the aqueous Ag(+) solution. It was found that the bands corresponding to the impurities had less influence in the Thiram analysis, which could be explained by the high affinity of sulfur for Ag surfaces. The influence of impurities in the SERS analyses therefore depended on the linkage between the rough silver surface and the analyte. The findings demonstrated the ease and effectiveness of using CPB to prepare a nanostructured surface for SERS. © The Author(s) 2016.

  11. The Impact of Array Detectors on Raman Spectroscopy

    Science.gov (United States)

    Denson, Stephen C.; Pommier, Carolyn J. S.; Denton, M. Bonner

    2007-01-01

    The impact of array detectors in the field of Raman spectroscopy and all low-light-level spectroscopic techniques is examined. The high sensitivity of array detectors has allowed Raman spectroscopy to be used to detect compounds at part per million concentrations and to perform Raman analyses at advantageous wavelengths.

  12. High-Pressure Raman and Calorimetry Studies of Vanadium(III) Alkyl Hydrides for Kubas-Type Hydrogen Storage.

    Science.gov (United States)

    Morris, Leah; Trudeau, Michel L; Reed, Daniel; Book, David; Antonelli, David M

    2016-03-16

    Reversible hydrogen storage under ambient conditions has been identified as a major bottleneck in enabling a future hydrogen economy. Herein, we report an amorphous vanadium(III) alkyl hydride gel that binds hydrogen through the Kubas interaction. The material possesses a gravimetric adsorption capacity of 5.42 wt % H2 at 120 bar and 298 K reversibly at saturation with no loss of capacity after ten cycles. This corresponds to a volumetric capacity of 75.4 kgH2  m(-3) . Raman experiments at 100 bar confirm that Kubas binding is involved in the adsorption mechanism. The material possesses an enthalpy of H2 adsorption of +0.52 kJ mol(-1) H2 , as measured directly by calorimetry, and this is practical for use in a vehicles without a complex heat management system.

  13. Raman and surface-enhanced Raman scattering (SERS) studies of the thrombin-binding aptamer.

    Science.gov (United States)

    Wu, Tsai-Chin; Vasudev, Milana; Dutta, Mitra; Stroscio, Michael A

    2013-06-01

    Surface-enhanced Raman scattering is used to study the Raman spectra and peak shifts the thrombin-binding aptamer (TBA) on substrates having two different geometries; one with a single stranded sequence and one with double stranded sequence. The Raman signals of the deoxyribonucleic acids on both substrates are enhanced and specific peaks of bases are identified. These results are highly reproducible and have promising applications in low cost nucleic acid detection.

  14. Wide-Field, Deep UV Raman Hyperspectral Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ChemImage Sensor Systems (CISS), teaming with the University of South Carolina, proposes a revolutionary wide-field Raman hyperspectral imaging system capable of...

  15. Channel temperature determination of a multifinger AlGaN/GaN high electron mobility transistor using a micro-Raman technique

    Institute of Scientific and Technical Information of China (English)

    Yang Li-Yuan; Xue Xiao-Yong; Zhang Kai; Zheng Xue-Feng; Ma Xiao-Hua; Hao Yue

    2012-01-01

    Self-heating in a multifinger AlGaN/GaN high electron mobility transistor (HEMT) is investigated by micro-Raman spectroscopy.The device temperature is probed on the die as a function of applied bias.The operating temperature of the AIGaN/GaN HEMT is estimated from the calibration curve of a passively heated AIGaN/GaN structure.A linear increase of junction temperature is observed when direct current dissipated power is increased.When the power dissipation is 12.75 W at a drain voltage of 15 V,a peak temperature of 69.1 ℃ is observed at the gate edge on the drain side of the central finger.The position of the highest temperature corresponds to the high-field region at the gate edge.

  16. In situ Raman and synchrotron X-ray diffraction study on crystallization of Choline chloride/Urea deep eutectic solvent under high pressure

    Science.gov (United States)

    Yuan, Chaosheng; Chu, Kunkun; Li, Haining; Su, Lei; Yang, Kun; Wang, Yongqiang; Li, Xiaodong

    2016-09-01

    Pressure-induced crystallization of Choline chloride/Urea (ChCl/Urea) deep eutectic solvent (DES) has been investigated by in-situ Raman spectroscopy and synchrotron X-ray diffraction. The results indicated that high pressure crystals appeared at around 2.6 GPa, and the crystalline structure was different from that formed at ambient pressure. Upon increasing the pressure, the Nsbnd H stretching modes of Urea underwent dramatic change after liquid-solid transition. It appears that high pressures may enhance the hydrogen bonds formed between ChCl and Urea. P versus T phase diagram of ChCl/Urea DES was constructed, and the crystallization mechanism of ChCl/Urea DES was discussed in view of hydrogen bonds.

  17. Coherent Raman spectroscopy

    CERN Document Server

    Eesley, G L

    1981-01-01

    Coherent Raman Spectroscopy provides a unified and general account of the fundamental aspects of nonlinear Raman spectroscopy, also known as coherent Raman spectroscopy. The theoretical basis from which coherent Raman spectroscopy developed is described, along with its applications, utility, and implementation as well as advantages and disadvantages. Experimental data which typifies each technique is presented. This book is comprised of four chapters and opens with an overview of nonlinear optics and coherent Raman spectroscopy, followed by a discussion on nonlinear transfer function of matter

  18. Raman effect on dark soliton trapping in high birefringence fiber%拉曼增益对高双折射光纤中暗孤子俘获的影响

    Institute of Scientific and Technical Information of China (English)

    闫青; 贾维国; 于宇; 张俊萍; 门克内木乐

    2015-01-01

    Not only the interaction between optical pulse and orbital electron but also the interaction between optical pulse and optical phonon needs to be considered when input pulse energy is large. The latter induces the simulated Raman scattering, thus generating the Raman gain. We analyze the effect of Raman gain, especially parallel Raman gain, on dark soliton trapping in high birefringence fiber by analytical method and numerical method. In the first part, we introduce some research results of soliton trapping obtained in recent years. In the second part, the coupled nonlinear Schr?dinger equation including Raman gain is utilized for high birefringence fiber. The trapping threshold of dark soliton with considering the Raman gain is deduced by the Lagrangian approach when input pulse is the dark soliton pulse that the amplitude of two polarized components of the dark soliton are the same (see formula (26)). Fig. 1. shows the relation between threshold and parallel Raman gain according to formula (26) when group velocity mismatching coefficient values are 0.15, 0.3, and 0.5 (vertical Raman gains are all 0.1). In the third part, the propagation of the two orthogonal polarization components of dark soliton is simulated by the fractional Fourier transform method. Figures 2-4 show respectively dark soliton trapping with group velocity mismatching coefficient values of 0.15, 0.3 and 0.5. We consider three situations in which Raman gain is not included and the parallel Raman gains are 0.4 and 0.6 when vertical Raman gains are both 0.1 in different group velocity mismatching coefficient values. We obtain the threshold of dark soliton by numerical method under different conditions and analyze the figures. At the same time, we compare the analytical solution with the numerical solution and discuss the effect of Raman gain on dark soliton trapping. The last part focuses on our conclusion. It is found that the threshold which is obtained by analytical method is smaller than that

  19. Dye-free near-infrared surface-enhanced Raman scattering nanoprobes for bioimaging and high-performance photothermal cancer therapy

    Science.gov (United States)

    Liu, Zhiming; Ye, Binggang; Jin, Mei; Chen, Haolin; Zhong, Huiqing; Wang, Xinpeng; Guo, Zhouyi

    2015-04-01

    Near-infrared surface-enhanced Raman scattering (NIR SERS) imaging is now a promising molecular imaging technology due to its narrow spectral bandwidth, low background interference and deep imaging depth. In this work, we report a novel strategy for fabrication of NIR SERS nanoprobes without using any expensive and highly toxic organic dyes. Multifunctional conducting polymer (CP) materials, serving as both biocompatible surface coatings and NIR-active reporters, are directly fabricated on the surface of gold nanorods (GNRs) via facile oxidative polymerization. The dye-free NIR SERS nanoprobes (GNR-CPs) exhibit good structural stability, good biocompatibility and intriguing NIR SERS activity. GNR-CPs also show an extraordinary NIR photothermal transduction efficiency, indicating the potential for cancer therapy. The applications of GNR-CPs as new types of theranostic agents for NIR SERS imaging and high-performance photothermal therapy are accomplished in vitro and in vivo.Near-infrared surface-enhanced Raman scattering (NIR SERS) imaging is now a promising molecular imaging technology due to its narrow spectral bandwidth, low background interference and deep imaging depth. In this work, we report a novel strategy for fabrication of NIR SERS nanoprobes without using any expensive and highly toxic organic dyes. Multifunctional conducting polymer (CP) materials, serving as both biocompatible surface coatings and NIR-active reporters, are directly fabricated on the surface of gold nanorods (GNRs) via facile oxidative polymerization. The dye-free NIR SERS nanoprobes (GNR-CPs) exhibit good structural stability, good biocompatibility and intriguing NIR SERS activity. GNR-CPs also show an extraordinary NIR photothermal transduction efficiency, indicating the potential for cancer therapy. The applications of GNR-CPs as new types of theranostic agents for NIR SERS imaging and high-performance photothermal therapy are accomplished in vitro and in vivo. Electronic

  20. High-Resolution Stimulated Raman Spectroscopy and Analysis of ν_2 and ν_3 Bands of of 13C_2H_4 Using the D2h Top Data System

    Science.gov (United States)

    Alkadrou, Abdulsamee; Rotger, Maud; Bermejo, Dionisio; Domenech, Jose Luis; Boudon, Vincent

    2016-06-01

    High resolution stimulated Raman spectra of 13C_2H_4 in the regions of the ν_2 and ν_3 Raman active modes have been recorded at at two temperatures (145 and 296 K) based on the quasi continuous-wave (cw) stimulated Raman spectrometer at Instituto de Estructura de la Materia (CSIC) in Madrid. A tensorial formalism adapted to X2Y4 planar asymmetric tops with D2h symmetry has been developed in Dijon and a program suite called D2hTDS (now part of the XTDS/SPVIEW spectroscopic software was proposed to calculate their high-resolution spectra. The effective Hamiltonian operator, involving a polyad structure, and transition moment (dipole moment and polarizability) operators can be systematically expanded to carry out global analyses of many rovibrational bands. A total of 103 and 51 lines corresponding to ν_2 and ν_3 Raman active modes have been assigned and fitted in frequency with a global root mean square deviation of 0.54 × 10-3 cm-1 and 0.36 × 10-3 cm-1, respectively. The figures below shows the stimulated Raman spectrum of the ν_2 and ν_3 bands of 13C_2H_4, compared to the simulation at 296 K. Raballand W, Rotger M, Boudon V, Loëte M. J Mol Spectrosc 2003;217:239-48. Wenger Ch, Boudon V, Rotger M, Champion JP, Sanzharov M. J Mol Spectrosc 2008;251:102-13.

  1. Gossiping Capabilities

    DEFF Research Database (Denmark)

    Mogensen, Martin; Frey, Davide; Guerraoui, Rachid

    Gossip-based protocols are now acknowledged as a sound basis to implement collaborative high-bandwidth content dissemination: content location is disseminated through gossip, the actual contents being subsequently pulled. In this paper, we present HEAP, HEterogeneity Aware gossip Protocol, where ...

  2. Confocal Raman-AFM, A New Tool for Materials Research

    Science.gov (United States)

    Schmidt, Ute

    2005-03-01

    Characterization of heterogeneous systems, e.g. polymers, on the nanometer scale continues to grow in importance and to impact key applications in the field of materials science, nanotechnology and catalysis. The development of advanced polymeric materials for such applications requires detailed information about the physical and chemical properties of these materials on the nanometer scale. However, some details about the phase-separation process in polymers are difficult to study with conventional characterization techniques due to the inability of these methods to chemically differentiate materials with good spatial resolution, without damage, staining or preferential solvent washing. The CR-AFM is a breakthrough in microscopy. It combines three measuring techniques in one instrument: a high resolution confocal optical microscope, an extremely sensitive Raman spectroscopy system, and an Atomic Force Microscope. Using this instrument, the high spatial and topographical resolution obtained with an AFM can be directly linked to the chemical information gained by Confocal Raman spectroscopy. To demonstrate the capabilities of this unique combination of measuring techniques, polymer blend films, spin coated on glass substrates, have been characterized. AFM measurements reveal the structural and mechanical properties of the films, whereas Raman spectral images show the chemical composition of the blends.

  3. Coherent anti-stokes Raman scattering microscopy: chemical imaging for biology and medicine.

    Science.gov (United States)

    Evans, Conor L; Xie, X Sunney

    2008-01-01

    Coherent anti-Stokes Raman scattering (CARS) microscopy is a label-free imaging technique that is capable of real-time, nonperturbative examination of living cells and organisms based on molecular vibrational spectroscopy. Recent advances in detection schemes, understanding of contrast mechanisms, and developments of laser sources have enabled superb sensitivity and high time resolution. Emerging applications, such as metabolite and drug imaging and tumor identification, raise many exciting new possibilities for biology and medicine.

  4. Stand-off detection of traces of explosives and precursors on fabrics by UV Raman spectroscopy

    Science.gov (United States)

    Chirico, Roberto; Almaviva, Salvatore; Botti, Sabina; Cantarini, Luciano; Colao, Francesco; Fiorani, Luca; Nuvoli, Marcello; Palucci, Antonio

    2012-10-01

    At the Diagnostic and Metrology Laboratory (ENEA) is under development a stand-off apparatus for trace detection of explosive compounds. The system is based on the Raman technique due to the high discrimination capabilities. All the optoelectronics components of the apparatus have been carefully designed as well as their optical matching. The main goal will be to detect low trace components within the respect of the eye safe regulation.

  5. Combat Medical Modernization: Posturing Low Supply And High Demand Assets To Meet Emerging And Future Capability Requirements

    Science.gov (United States)

    2015-07-01

    the Asia - Pacific .66 This shift could bring new requirements for military projection of power and therefore needed medical capability into an area...Lead Agent Medical Materiel – Pacific (TLAMM-P) as well as leading an MFST (Mobile Field Surgical Team) team in the CENTCOM Area of Operation (AOR...duty as Independent Duty Medical Technician (IDMT), Aeromedical Evacuation Technician (AET), Hyperbaric Medical Technician (HBMT); Allergy and/or

  6. Investigation into high-pressure behavior of MnTiO3: X-ray diffraction and Raman spectroscopy with diamond anvil cells

    Directory of Open Access Journals (Sweden)

    Xiang Wu

    2011-01-01

    Full Text Available The structural stability of manganese titanate MnTiO3 at high pressure was investigated by X-ray diffraction and Raman spectroscopy with diamond anvil cells. Ilmenite-type MnTiO3 is stable at least to 26.6 GPa, and lithium niobate type MnTiO3 reversibly transforms at room temperature to perovskite at 2.0 GPa. Bulk moduli (K300 of ilmenite, lithium niobate and perovskite are 174(4 GPa, 179(8 GPa, and 208(5 GPa, respectively (at fixed first pressure derivative K′ = 4. The Grüneisen parameter γ has been estimated to be 1.28 for ilmenite and 1.75 for perovskite. In ilmenite phase, TiO6 octahedra become more regular with increasing pressure. In perovskite phase structural distortion increases with pressure increase.

  7. Evidence of iso-structural phase transition in high pressure Raman spectroscopic studies of CaCu3Ti4O12

    Science.gov (United States)

    Tyagi, Shekhar; Sharma, Gaurav; Sathe, V. G.

    2017-02-01

    High pressure Raman spectroscopic studies on Polycrystalline CaCu3Ti4O12 and SrCu3Ti4O12 compounds are carried out in order to validate the theoretical predictions of a structural transformation near 3-4 GPa and an insulator to metal transition above 7 GPa [S. B. Fagan et al., Phys. Rev. B 72, 014106 (2005)]. Our studies showed normal hardening and broadening of peaks with increasing pressure up to 20 GPa besides a discontinuity between 8 and 9 GPa which is attributed to an isostructural phase transition. The Ag(1) peak occurring at 442 cm-1 showed asymmetric Fano lineshape and the lineshape parameter 'q' shows an increase with increasing pressure. This is completely against the theoretical predictions of an insulator to metal transition above 7 GPa.

  8. Raman spectroscopic analysis of geological and biogeological specimens of relevance to the ExoMars mission.

    Science.gov (United States)

    Edwards, Howell G M; Hutchinson, Ian B; Ingley, Richard; Parnell, John; Vítek, Petr; Jehlička, Jan

    2013-06-01

    A novel miniaturized Raman spectrometer is scheduled to fly as part of the analytical instrumentation package on an ESA remote robotic lander in the ESA/Roscosmos ExoMars mission to search for evidence for extant or extinct life on Mars in 2018. The Raman spectrometer will be part of the first-pass analytical stage of the sampling procedure, following detailed surface examination by the PanCam scanning camera unit on the ExoMars rover vehicle. The requirements of the analytical protocol are stringent and critical; this study represents a laboratory blind interrogation of specimens that form a list of materials that are of relevance to martian exploration and at this stage simulates a test of current laboratory instrumentation to highlight the Raman technique strengths and possible weaknesses that may be encountered in practice on the martian surface and from which future studies could be formulated. In this preliminary exercise, some 10 samples that are considered terrestrial representatives of the mineralogy and possible biogeologically modified structures that may be identified on Mars have been examined with Raman spectroscopy, and conclusions have been drawn about the viability of the unambiguous spectral identification of biomolecular life signatures. It is concluded that the Raman spectroscopic technique does indeed demonstrate the capability to identify biomolecular signatures and the mineralogy in real-world terrestrial samples with a very high degree of success without any preconception being made about their origin and classification.

  9. High-order Stokes and anti-Stokes Raman generation in monoisotopic CVD {sup 12}C-diamond

    Energy Technology Data Exchange (ETDEWEB)

    Kaminskii, Alexander A. [Institute of Crystallography, Russian Academy of Sciences, Moscow (Russian Federation); Lux, Oliver; Rhee, Hanjo; Eichler, Hans J. [Institute of Optics and Atomic Physics, Technische Universitaet Berlin (Germany); Ralchenko, Victor G.; Bolshakov, Andrey P. [General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Shirakawa, Akira; Yoneda, Hitoki [Institute for Laser Science, University of Electro-Communications, Tokyo (Japan)

    2016-06-15

    We determined, for the first time, the room temperature phonon energy related to the F{sub 2g} vibration mode (ω{sub SRS(12C)} ∝ 1333.2 cm{sup -1}) in a mono-crystalline single-isotope CVD {sup 12}C-diamond crystal by means of stimulated Raman scattering (SRS) spectroscopy. Picosecond one-micron excitation using a Nd{sup 3+}:Y{sub 3}Al{sub 5}O{sub 12}-laser generates a nearly two-octave spanning SRS frequency comb (∝12000 cm{sup -1}) consisting of higher-order Stokes and anti-Stokes components. The spacing of the spectral lines was found to differ by Δω{sub SRS} ∝ 0.9 cm{sup -1} from the comb spacing (ω{sub SRS(natC)} ∝ 1332.3 cm{sup -1}) when pumping a conventional CVD diamond crystal with a natural composition of the two stable carbon isotopes {sup 12}C (98.93%) and {sup 13}C (1.07%). (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Visualizing Cell State Transition Using Raman Spectroscopy

    Science.gov (United States)

    Ichimura, Taro; Chiu, Liang-da; Fujita, Katsumasa; Kawata, Satoshi; Watanabe, Tomonobu M.; Yanagida, Toshio; Fujita, Hideaki

    2014-01-01

    System level understanding of the cell requires detailed description of the cell state, which is often characterized by the expression levels of proteins. However, understanding the cell state requires comprehensive information of the cell, which is usually obtained from a large number of cells and their disruption. In this study, we used Raman spectroscopy, which can report changes in the cell state without introducing any label, as a non-invasive method with single cell capability. Significant differences in Raman spectra were observed at the levels of both the cytosol and nucleus in different cell-lines from mouse, indicating that Raman spectra reflect differences in the cell state. Difference in cell state was observed before and after the induction of differentiation in neuroblastoma and adipocytes, showing that Raman spectra can detect subtle changes in the cell state. Cell state transitions during embryonic stem cell (ESC) differentiation were visualized when Raman spectroscopy was coupled with principal component analysis (PCA), which showed gradual transition in the cell states during differentiation. Detailed analysis showed that the diversity between cells are large in undifferentiated ESC and in mesenchymal stem cells compared with terminally differentiated cells, implying that the cell state in stem cells stochastically fluctuates during the self-renewal process. The present study strongly indicates that Raman spectral morphology, in combination with PCA, can be used to establish cells' fingerprints, which can be useful for distinguishing and identifying different cellular states. PMID:24409302

  11. Fluorescence-suppressed time-resolved Raman spectroscopy of pharmaceuticals using complementary metal-oxide semiconductor (CMOS) single-photon avalanche diode (SPAD) detector.

    Science.gov (United States)

    Rojalin, Tatu; Kurki, Lauri; Laaksonen, Timo; Viitala, Tapani; Kostamovaara, Juha; Gordon, Keith C; Galvis, Leonardo; Wachsmann-Hogiu, Sebastian; Strachan, Clare J; Yliperttula, Marjo

    2016-01-01

    In this work, we utilize a short-wavelength, 532-nm picosecond pulsed laser coupled with a time-gated complementary metal-oxide semiconductor (CMOS) single-photon avalanche diode (SPAD) detector to acquire Raman spectra of several drugs of interest. With this approach, we are able to reveal previously unseen Raman features and suppress the fluorescence background of these drugs. Compared to traditional Raman setups, the present time-resolved technique has two major improvements. First, it is possible to overcome the strong fluorescence background that usually interferes with the much weaker Raman spectra. Second, using the high photon energy excitation light source, we are able to generate a stronger Raman signal compared to traditional instruments. In addition, observations in the time domain can be performed, thus enabling new capabilities in the field of Raman and fluorescence spectroscopy. With this system, we demonstrate for the first time the possibility of recording fluorescence-suppressed Raman spectra of solid, amorphous and crystalline, and non-photoluminescent and photoluminescent drugs such as caffeine, ranitidine hydrochloride, and indomethacin (amorphous and crystalline forms). The raw data acquired by utilizing only the picosecond pulsed laser and a CMOS SPAD detector could be used for identifying the compounds directly without any data processing. Moreover, to validate the accuracy of this time-resolved technique, we present density functional theory (DFT) calculations for a widely used gastric acid inhibitor, ranitidine hydrochloride. The obtained time-resolved Raman peaks were identified based on the calculations and existing literature. Raman spectra using non-time-resolved setups with continuous-wave 785- and 532-nm excitation lasers were used as reference data. Overall, this demonstration of time-resolved Raman and fluorescence measurements with a CMOS SPAD detector shows promise in diverse areas, including fundamental chemical research, the

  12. Fiber array based hyperspectral Raman imaging for chemical selective analysis of malaria-infected red blood cells.

    Science.gov (United States)

    Brückner, Michael; Becker, Katja; Popp, Jürgen; Frosch, Torsten

    2015-09-24

    A new setup for Raman spectroscopic wide-field imaging is presented. It combines the advantages of a fiber array based spectral translator with a tailor-made laser illumination system for high-quality Raman chemical imaging of sensitive biological samples. The Gaussian-like intensity distribution of the illuminating laser beam is shaped by a square-core optical multimode fiber to a top-hat profile with very homogeneous intensity distribution to fulfill the conditions of Koehler. The 30 m long optical fiber and an additional vibrator efficiently destroy the polarization and coherence of the illuminating light. This homogeneous, incoherent illumination is an essential prerequisite for stable quantitative imaging of complex biological samples. The fiber array translates the two-dimensional lateral information of the Raman stray light into separated spectral channels with very high contrast. The Raman image can be correlated with a corresponding white light microscopic image of the sample. The new setup enables simultaneous quantification of all Raman spectra across the whole spatial area with very good spectral resolution and thus outperforms other Raman imaging approaches based on scanning and tunable filters. The unique capabilities of the setup for fast, gentle, sensitive, and selective chemical imaging of biological samples were applied for automated hemozoin analysis. A special algorithm was developed to generate Raman images based on the hemozoin distribution in red blood cells without any influence from other Raman scattering. The new imaging setup in combination with the robust algorithm provides a novel, elegant way for chemical selective analysis of the malaria pigment hemozoin in early ring stages of Plasmodium falciparum infected erythrocytes.

  13. Self-assembled LiFePO4 nanowires with high rate capability for Li-ion batteries.

    Science.gov (United States)

    Peng, Lele; Zhao, Yu; Ding, Yu; Yu, Guihua

    2014-08-28

    Controlling the dimensions in the nanometer scale of olivine-type LiFePO4 has been regarded as one of the most effective strategies to improve its electrochemical performance for Li-ion batteries. In this communication, we demonstrate a novel LiFePO4 nanoarchitecture, which is composed of self-assembled single-crystalline nanowires and exhibits good rate capability with a reversible capacity of ∼110 mA h g(-1) at a current rate of 30 C, and a stable capacity retention of ∼86% after 1000 cycles at a current rate of 10 C.

  14. One-step green synthesis of β-cyclodextrin/iron oxide-reduced graphene oxide nanocomposite with high supramolecular recognition capability: Application for vortex-assisted magnetic solid phase extraction of organochlorine pesticides residue from honey samples.

    Science.gov (United States)

    Mahpishanian, Shokouh; Sereshti, Hassan

    2017-02-17

    In this research, β-cyclodextrin/iron oxide reduced graphene oxide hybrid nanostructure (β-CD/MRGO) with high water dispersability, excellent magnetic responsivity and molecular selectivity was prepared via a facile one step green strategy. The obtained nanomaterial was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, and vibrating sample magnetometry (VSM), which confirmed the modification of GO with β-CD and magnetic nanoparticles. The formation mechanism of β-CD/MRGO was also discussed. The prepared magnetic nanocomposite was then applied as adsorbent in the vortex-assisted magnetic solid phase extraction (MSPE) of 16 organochlorine pesticides (OCPs) from honey samples prior to gas chromatography-electron capture detection (GC-ECD) analysis. Optimum extraction conditions have been assessed with respect to vortex time, sample pH, adsorbent amount, and salt concentration as well as desorption conditions (type and volume of desorption solvent and desorption time). A good level of linearity (2-10,000ngkg(-1)) with satisfactory determination coefficients (R(2)>0.9966) and suitable precision (%RSDs less than 7.8) was obtained for OCPs under the optimal conditions. The limits of detection and quantification of the method were obtained in the sub-parts per trillion (ppt) to parts per trillion range (LOD: 0.52-3.21ngkg(-1); LOQ: 1.73-10.72ngkg(-1)) based on 3 and 10 signal to noise ratios, respectively. The MSPE method was successfully applied to analysis of OCPs in honey samples with recoveries in the range of 78.8% to 116.2% and RSDs (n=3) below 8.1%. The results demonstrated that β-CD/MRGO could exhibit good supramolecular recognition, enrichment capability and high extraction recoveries toward OCPs. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Confocal Raman Microscopy

    CERN Document Server

    Dieing, Thomas; Toporski, Jan

    2011-01-01

    Confocal Raman Microscopy is a relatively new technique that allows chemical imaging without specific sample preparation. By integrating a sensitive Raman spectrometer within a state-of-the-art microscope, Raman microscopy with a spatial resolution down to 200nm laterally and 500nm vertically can be achieved using visible light excitation. Recent developments in detector and computer technology as well as optimized instrument design have reduced integration times of Raman spectra by orders of magnitude, so that complete images consisting of tens of thousands of Raman spectra can be acquired in seconds or minutes rather than hours, which used to be standard just one decade ago. The purpose of this book is to provide the reader a comprehensive overview of the rapidly developing field of Confocal Raman Microscopy and its applications.

  16. Cascaded-cladding-pumped cascaded Raman fiber amplifier.

    Science.gov (United States)

    Jiang, Huawei; Zhang, Lei; Feng, Yan

    2015-06-01

    The conversion efficiency of double-clad Raman fiber laser is limited by the cladding-to-core area ratio. To get high conversion efficiency, the inner-cladding-to-core area ratio has to be less than about 8, which limits the brightness enhancement. To overcome the problem, a cascaded-cladding-pumped cascaded Raman fiber laser with multiple-clad fiber as the Raman gain medium is proposed. A theoretical model of Raman fiber amplifier with multiple-clad fiber is developed, and numerical simulation proves that the proposed scheme can improve the conversion efficiency and brightness enhancement of cladding pumped Raman fiber laser.

  17. Cavity-enhanced Raman Microscopy of Individual Carbon Nanotubes

    CERN Document Server

    Hümmer, Thomas; Hofmann, Matthias S; Hänsch, Theodor W; Högele, Alexander; Hunger, David

    2015-01-01

    Raman spectroscopy reveals chemically specific information, and combined with imaging provides label-free insight into the molecular world. However, the signals are intrinsically weak and call for enhancement techniques. Here we use a tunable high-finesse optical microcavity to demonstrate Purcell enhancement of Raman scattering in combination with high-resolution scanning-cavity imaging. We detect cavity-enhanced Raman spectra of individual single-walled carbon nanotubes, expand the technique to hyperspectral imaging, and co-localize measurements with cavity-enhanced absorption microscopy. Direct comparison with confocal Raman microscopy yields a 550-times enhanced collectable Raman scattering spectral density and a 11-fold enhancement of the integrated count rate. The quantitative character, the inherent spectral filtering, and the absence of intrinsic background in cavity-vacuum stimulated Raman scattering renders our technique a promising tool for molecular imaging. Furthermore, cavity-enhanced Raman tran...

  18. Raman Spectra of Glasses

    Science.gov (United States)

    1986-11-30

    17), Raman spectra, plus a , . theoretical treatment of the data, f complex fluorozirconate 14 I anions in ZBLAN glasses and melts (16), and...based ZBLAN glasses ) 17. ICORS (International Conference on Raman Spectroscopy) Proceedings, London, England. Conferencf 5-9 Sep 88. (Molten silica...RESEARCH FINAL REPORT DTIC CONTRACT N00014-81-K-0501 &JELECTE 1 MAY 81 -- 30 NOV 86 EJJAN041989 V "RAMAN SPECTRA OF GLASSES " 0 During the five years of the

  19. 江苏高技术产业创新能力的实证研究%The Analysis on High-tech Industry Innovation Capability in Jiangsu

    Institute of Scientific and Technical Information of China (English)

    马澜

    2012-01-01

    Product of Hi-tech Industry in Jiangsu is great. To find out the state of innovation capability in Jiangsu' s Hi-tech Industry, we design an evaluation index system of high-technology industry's innovation capability from the perspective of innovation input, output and conditions. Grey Incidence Degrees model was employed to make synthetic estimation for high-technology industry's innovation capability in Jiangsu. On this basis,some suggestions on improving high-technology industry's innovation capability in Jiangsu are put forward.%江苏是高技术产业大省,针对江苏高技术产业的创新能力,本文从创新环境、创新投入和创新产出三个维度建立了创新能力评价指标体系,运用灰色关联法对江苏高技术产业主要子行业的创新能力进行了综合评价,并在此基础上给出了江苏高技术产业创新能力提升的相关建议。

  20. Photonics crystal fiber Raman sensors

    Science.gov (United States)

    Yang, Xuan; Bond, Tiziana C.; Zhang, Jin Z.; Li, Yat; Gu, Claire

    2012-11-01

    Hollow core photonic crystal fiber (HCPCF) employs a guiding mechanism fundamentally different from that in conventional index guiding fibers. In an HCPCF, periodic air channels in a glass matrix act as reflectors to confine light in an empty core. As a result, the interaction between light and glass can be very small. Therefore, HCPCF has been used in applications that require extremely low non-linearity, high breakdown threshold, and zero dispersion. However, their applications in optical sensing, especially in chemical and biological sensing, have only been extensively explored recently. Besides their well-recognized optical properties the hollow cores of the fibers can be easily filled with liquid or gas, providing an ideal sampling mechanism in sensors. Recently, we have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or surface enhanced Raman scattering (SERS) applications. This is because the confinement of both light and sample inside the hollow core enables direct interaction between the propagating wave and the analyte. In this paper, we report our recent work on using HCPCF as a platform for Raman or SERS in the detection of low concentration greenhouse gas (ambient CO2), biomedically significant molecules (e.g., glucose), and bacteria. We have demonstrated that by filling up a HCPCF with gas or liquid samples, it is possible to significantly increase the sensitivity of the sensors in either regular Raman or SERS applications.

  1. Remote Raman - laser induced breakdown spectroscopy (LIBS) geochemical investigation under Venus atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Clegg, Sanuel M [Los Alamos National Laboratory; Barefield, James E [Los Alamos National Laboratory; Humphries, Seth D [Los Alamos National Laboratory; Wiens, Roger C [Los Alamos National Laboratory; Vaniman, D. T. [Los Alamos National Laboratory; Sharma, S. K. [UNIV OF HAWAII; Misra, A. K. [UNIV OF HAWAII; Dyar, M. D. [MT. HOLYOKE COLLEGE; Smrekar, S. E. [JET PROPULSION LAB.

    2010-12-13

    The extreme Venus surface temperatures ({approx}740 K) and atmospheric pressures ({approx}93 atm) create a challenging environment for surface missions. Scientific investigations capable of Venus geochemical observations must be completed within hours of landing before the lander will be overcome by the harsh atmosphere. A combined remote Raman - LIBS (Laser Induced Breakdown Spectroscopy) instrument is capable of accomplishing the geochemical science goals without the risks associated with collecting samples and bringing them into the lander. Wiens et al. and Sharma et al. demonstrated that both analytical techniques can be integrated into a single instrument capable of planetary missions. The focus of this paper is to explore the capability to probe geologic samples with Raman - LIBS and demonstrate quantitative analysis under Venus surface conditions. Raman and LIBS are highly complementary analytical techniques capable of detecting both the mineralogical and geochemical composition of Venus surface materials. These techniques have the potential to profoundly increase our knowledge of the Venus surface composition, which is currently limited to geochemical data from Soviet Venera and VEGA landers that collectively suggest a surface composition that is primarily tholeiitic basaltic with some potentially more evolved compositions and, in some locations, K-rich trachyandesite. These landers were not equipped to probe the surface mineralogy as can be accomplished with Raman spectroscopy. Based on the observed compositional differences and recognizing the imprecise nature of the existing data, 15 samples were chosen to constitute a Venus-analog suite for this study, including five basalts, two each of andesites, dacites, and sulfates, and single samples of a foidite, trachyandesite, rhyolite, and basaltic trachyandesite under Venus conditions. LIBS data reduction involved generating a partial least squares (PLS) model with a subset of the rock powder standards to

  2. Sandia QIS Capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Richard P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-07-01

    Sandia National Laboratories has developed a broad set of capabilities in quantum information science (QIS), including elements of quantum computing, quantum communications, and quantum sensing. The Sandia QIS program is built atop unique DOE investments at the laboratories, including the MESA microelectronics fabrication facility, the Center for Integrated Nanotechnologies (CINT) facilities (joint with LANL), the Ion Beam Laboratory, and ASC High Performance Computing (HPC) facilities. Sandia has invested $75 M of LDRD funding over 12 years to develop unique, differentiating capabilities that leverage these DOE infrastructure investments.

  3. Raman crystallography of RNA.

    Science.gov (United States)

    Gong, Bo; Chen, Jui-Hui; Yajima, Rieko; Chen, Yuanyuan; Chase, Elaine; Chadalavada, Durga M; Golden, Barbara L; Carey, Paul R; Bevilacqua, Philip C

    2009-10-01

    Raman crystallography is the application of Raman spectroscopy to single crystals. This technique has been applied to a variety of protein molecules where it has provided unique information about biopolymer folding, substrate binding, and catalysis. Here, we describe the application of Raman crystallography to functional RNA molecules. RNA represents unique opportunities and challenges for Raman crystallography. One issue that confounds studies of RNA is its tendency to adopt multiple non-functional folds. Raman crystallography has the advantage that it isolates a single state of the RNA within the crystal and can evaluate its fold, metal ion binding properties (ligand identity, stoichiometry, and affinity), proton binding properties (identity, stoichiometry, and affinity), and catalytic potential. In particular, base-specific stretches can be identified and then associated with the binding of metal ions and protons. Because measurements are carried out in the hanging drop at ambient, rather than cryo, conditions and because RNA crystals tend to be approximately 70% solvent, RNA dynamics and conformational changes become experimentally accessible. This review focuses on experimental setup and procedures, acquisition and interpretation of Raman data, and determination of physicochemical properties of the RNA. Raman crystallographic and solution biochemical experiments on the HDV RNA enzyme are summarized and found to be in excellent agreement. Remarkably, characterization of the crystalline state has proven to help rather than hinder functional characterization of functional RNA, most likely because the tendency of RNA to fold heterogeneously is limited in a crystalline environment. Future applications of Raman crystallography to RNA are briefly discussed.

  4. Portable raman explosives detection

    Energy Technology Data Exchange (ETDEWEB)

    Moore, David Steven [Los Alamos National Laboratory; Scharff, Robert J [Los Alamos National Laboratory

    2008-01-01

    Recent advances in portable Raman instruments have dramatically increased their application to emergency response and forensics, as well as homeland defense. This paper reviews the relevant attributes and disadvantages of portable Raman spectroscopy, both essentially and instrumentally, to the task of explosives detection in the field.

  5. Implementation of Deep Ultraviolet Raman Spectroscopy

    DEFF Research Database (Denmark)

    Liu, Chuan

    , with particular focus on obtaining high quality of the final measurements. This naturally involves themes such as spectral resolution, sensitivity, elimination of background noise, and so on. Compared to Raman spectra excited with visible light, the DUV excited Raman spectra tend to have a markedly lower spectral...... resolution. The spectral resolution is an important factor to consider when using the DUV excited Raman spectroscopy. In line with this insight is the fact that we found a way to improve the knowledge on the spectral resolution of the DUV excited spectrum. A new method was invented during the project...... (absorption, condensation) are described. We have found a way to solve the problems, and our solution, using a special designed gas gap cell to obtain measurements of extraordinary high quality, are presented. The DUV Raman spectra of gasoline were excited by three different wavelengths, 257.3, 244.0 and 229...

  6. Condensing Raman spectrum for single-cell phenotype analysis

    KAUST Repository

    Sun, Shiwei

    2015-12-09

    Background In recent years, high throughput and non-invasive Raman spectrometry technique has matured as an effective approach to identification of individual cells by species, even in complex, mixed populations. Raman profiling is an appealing optical microscopic method to achieve this. To fully utilize Raman proling for single-cell analysis, an extensive understanding of Raman spectra is necessary to answer questions such as which filtering methodologies are effective for pre-processing of Raman spectra, what strains can be distinguished by Raman spectra, and what features serve best as Raman-based biomarkers for single-cells, etc. Results In this work, we have proposed an approach called rDisc to discretize the original Raman spectrum into only a few (usually less than 20) representative peaks (Raman shifts). The approach has advantages in removing noises, and condensing the original spectrum. In particular, effective signal processing procedures were designed to eliminate noise, utilising wavelet transform denoising, baseline correction, and signal normalization. In the discretizing process, representative peaks were selected to signicantly decrease the Raman data size. More importantly, the selected peaks are chosen as suitable to serve as key biological markers to differentiate species and other cellular features. Additionally, the classication performance of discretized spectra was found to be comparable to full spectrum having more than 1000 Raman shifts. Overall, the discretized spectrum needs about 5storage space of a full spectrum and the processing speed is considerably faster. This makes rDisc clearly superior to other methods for single-cell classication.

  7. Development of a full micro-scale spatially offset Raman spectroscopy prototype as a portable analytical tool.

    Science.gov (United States)

    Realini, Marco; Conti, Claudia; Botteon, Alessandra; Colombo, Chiara; Matousek, Pavel

    2017-01-16

    We present, for the first time, a portable full micro-Spatially Offset Raman Spectroscopy (micro-SORS) prototype permitting the in situ analysis of thin, highly turbid stratified layers at depths not accessible to conventional Raman microscopy. The technique is suitable for the characterisation of painted layers in panels, canvases and mural paintings, painted statues and decorated objects in cultural heritage or stratified polymers, and biological, catalytic and forensics samples where invasive analysis is undesirable or impossible to perform. The new device is characterised conceptually in polymer and paint layer systems. The provision of portability with full micro-SORS delivers subsurface micro-SORS capability unlocking the non-invasive and non-destructive potential of micro-SORS at its most effective form permitting it to be applied to large and non-portable objects in situ without recourse to removing micro-fragments for laboratory analysis on benchtop Raman microscopes.

  8. Application of resonance Raman spectroscopy as a nuclear proliferation detection technology

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A.J. III; Chen, C.L.; Dougherty, D.R.

    1993-01-01

    Resonance Raman spectroscopy (RRS) potentially possesses many of the characteristics of an ideal verification technology. Some of these ideal traits are: very high selectivity and specificity to allow the deconvolution of a mixture of the chemicals of interest, high sensitivity in order to measure a species at trace levels, high reliability and long-term durability, applicability to a wide range of chemicals capability for sensing in a variety of environmental conditions, independence of the physical state of the chemical capability for quantitative analysis, and finally, but no less important capability for full signal development within seconds. In this presentation, the potential of RRS as a detection/identification technology for chemicals pertinent to nuclear materials production and processing will be assessed. A review of the basic principles behind this technique, both theoretical and experimental, will be discussed along with some recent results obtained in this laboratory. Raman scattering is a coherent, inelastic, two-photon scattering process where an exciting photon of energy hv promotes a molecule to a virtual level and the subsequently emitted photon is shifted in frequency in accordance with the rotational-vibrational structure of the irradiated species, therefore providing a unique fingerprint of the molecule. The enhancement of a Raman signal occurs when the excitation frequency is isoenergetic with an allowed electronic transition. Under resonance conditions, scattering cross-sections have been enhanced up to 6 orders of magnitude, thereby allowing the measurement of resonance Raman spectra from concentrations as dilute as 20 ppb for PAHs (with the potential of pptr). In detection/verification programs, this condition translates to increased sensitivity (ppm/ppb) and increased probing distance (m/km).

  9. Application of resonance Raman spectroscopy as a nuclear proliferation detection technology

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, A.J. III; Chen, C.L.; Dougherty, D.R.

    1993-03-01

    Resonance Raman spectroscopy (RRS) potentially possesses many of the characteristics of an ideal verification technology. Some of these ideal traits are: very high selectivity and specificity to allow the deconvolution of a mixture of the chemicals of interest, high sensitivity in order to measure a species at trace levels, high reliability and long-term durability, applicability to a wide range of chemicals capability for sensing in a variety of environmental conditions, independence of the physical state of the chemical capability for quantitative analysis, and finally, but no less important capability for full signal development within seconds. In this presentation, the potential of RRS as a detection/identification technology for chemicals pertinent to nuclear materials production and processing will be assessed. A review of the basic principles behind this technique, both theoretical and experimental, will be discussed along with some recent results obtained in this laboratory. Raman scattering is a coherent, inelastic, two-photon scattering process where an exciting photon of energy hv promotes a molecule to a virtual level and the subsequently emitted photon is shifted in frequency in accordance with the rotational-vibrational structure of the irradiated species, therefore providing a unique fingerprint of the molecule. The enhancement of a Raman signal occurs when the excitation frequency is isoenergetic with an allowed electronic transition. Under resonance conditions, scattering cross-sections have been enhanced up to 6 orders of magnitude, thereby allowing the measurement of resonance Raman spectra from concentrations as dilute as 20 ppb for PAHs (with the potential of pptr). In detection/verification programs, this condition translates to increased sensitivity (ppm/ppb) and increased probing distance (m/km).

  10. Single-pulse stimulated Raman scattering spectroscopy

    CERN Document Server

    Frostig, Hadas; Natan, Adi; Silberberg, Yaron

    2010-01-01

    We demonstrate the acquisition of stimulated Raman scattering spectra with the use of a single femtosecond pulse. High resolution vibrational spectra are obtained by shifting the phase of a narrow band of frequencies in the broadband input pulse spectrum, using spectral shaping. The vibrational spectrum is resolved by examining the amplitude features formed in the spectrum after interaction with the sample. Using this technique, low frequency Raman lines (<100cm^-1) are resolved in a straightforward manner.

  11. Coherent anti-Stokes Raman scattering microscopy (CARS): Instrumentation and applications

    Energy Technology Data Exchange (ETDEWEB)

    Djaker, Nadia [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France); Lenne, Pierre-Francois [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France); Marguet, Didier [Centre d' Immunologie de Marseille-Luminy, Universite de la Mediterranee, Case 906, F-13288 Marseille Cedex 9 (France); INSERM, UMR631, Marseille (France); CNRS, UMR6102, Marseille (France); Colonna, Anne [L' Oreal Recherche, Aulnay Sous bois (France); Hadjur, Christophe [L' Oreal Recherche, Aulnay Sous bois (France); Rigneault, Herve [Institut Fresnel, Mosaic team, CNRS UMR 6133, Universite Paul Cezanne (Aix-Marseille III), F-1397 Marseille Cedex 20 (France)]. E-mail: herve.rigneault@fresnel.fr

    2007-02-01

    Recent advances in laser physics have permitted the development of a new kind of microscopy based on stimulated Raman scattering. This new technique known as Coherent anti-Stokes Raman scattering (CARS) microscopy allows vibrational imaging with high sensitivity, high spectral resolution and three-dimensional sectioning capabilities. We review recent advances in CARS microscopy, with applications to chemical and biological systems. We also present an application of CARS microscopy with high optical resolution and spectral selectivity, in resolving structures in surface ex vivo stratum corneum by looking at the CH{sub 2} stretching vibrational band. A strong CARS signal is backscattered from an intense forward generated CARS signal in thick samples. This makes noninvasive imaging of deep structures possible, without labeling or chemical treatments.

  12. Generation of High Power 1.54 Micrometers Radiation by Stimulated Raman Scattering in Methane (Opwekking van Hoogvermogen 1.54 Micrometers Straling m.b. v. Gestimuleerde Raman Verstrooiing in Methaan)

    Science.gov (United States)

    1990-08-01

    uitlijning het rendement bepalen. Omdat per Nd:YAG laser foton maximaal 66n 1.543 pm foton gevormd kan worden, wordt het foton rendement gebruikt als... foton conversie wordt hiervan 122.5 mJ via Raman verstrooing omgezet. Hiervan koint 84.5 mi in de vorm van 1.54 pum straling uit het focale gebied en...frequentie, met laserdiafragma’s van 1.5 tot 5 mm, foton rendementen gehaald van 47 tot 61%. Het hoogst bereikte rendement met een sferische lens was 61

  13. Structure of shock compressed model basaltic glass: Insights from O K-edge X-ray Raman scattering and high-resolution 27Al NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Keun; Park, Sun Young; Kim, Hyo-Im; Tschauner, Oliver; Asimow, Paul; Bai, Ligang; Xiao, Yuming; Chow, Paul (UNLV); (SNU); (CIT); (CIW)

    2012-05-29

    The detailed atomic structures of shock compressed basaltic glasses are not well understood. Here, we explore the structures of shock compressed silicate glass with a diopside-anorthite eutectic composition (Di{sub 64}An{sub 36}), a common Fe-free model basaltic composition, using oxygen K-edge X-ray Raman scattering and high-resolution {sup 27}Al solid-state NMR spectroscopy and report previously unknown details of shock-induced changes in the atomic configurations. A topologically driven densification of the Di{sub 64}An{sub 36} glass is indicated by the increase in oxygen K-edge energy for the glass upon shock compression. The first experimental evidence of the increase in the fraction of highly coordinated Al in shock compressed glass is found in the {sup 27}Al NMR spectra. This unambiguous evidence of shock-induced changes in Al coordination environments provides atomistic insights into shock compression in basaltic glasses and allows us to microscopically constrain the magnitude of impact events or relevant processes involving natural basalts on Earth and planetary surfaces.

  14. High pressure phases in NWA 8711, a shock melted L6 chondrite from Northwest Africa: a combined Raman and EMPA study.

    Science.gov (United States)

    Moggi Cecchi, V.; Pratesi, G.; Caporali, S.; Zoppi, M.

    We report the occurrence of two coexisting high-pressure assemblages in shock-induced black veins of NWA 8711, an L6 chondrite recently found in Northwest Africa. The main phases of the host rock are olivine, enstatite, diopside, plagioclase, iron-nickel alloy and troilite. The presence of typical shock metamorphic features both in olivine and pyroxene, as well as of maskelynite and melt veins point to a shock stage S6. Two coexisting distinct assemblages were observed in the shock-melted areas: (1) a very fine-grained intergrowth of silicate phases sprinkled with fine-grained metal and troilite blebs and (2) a coarser-grained polycrystalline aggregate consisting of ringwoodite crystals. EMPA analyses were performed on both the chondritic matrix and on individual grains of the shock-melted area to characterize their mineralogical composition. EMPA analyses on the coarse-grained area suggested the presence of shock-generated ringwoodite and low-Ca majorite. These data are confirmed by Micro-Raman point analyses. The analyses performed on the fine-grained portion of the veins allowed to determine the presence of a majorite-pyrope solid solution. According to literature data the majorite-pyrope solid solution suggests a crystallization from a shock-melted chondritic matrix under high pressures and temperatures. Ringwoodite and low-Ca majorite were instead formed by solid state transformation of olivine and low-Ca pyroxene originally present in the meteorite.

  15. Irradiation effects in 6H-SiC induced by neutron and heavy ions: Raman spectroscopy and high-resolution XRD analysis

    Science.gov (United States)

    Chen, Xiaofei; Zhou, Wei; Feng, Qijie; Zheng, Jian; Liu, Xiankun; Tang, Bin; Li, Jiangbo; Xue, Jianming; Peng, Shuming

    2016-09-01

    Irradiation effects of neutron and 3 MeV C+, Si+ in 6H-SiC were investigated by Raman spectroscopy and high-resolution XRD. The total disorder values of neutron irradiated SiC agree well with that of samples irradiated by ions at the same doses respectively. On the other hand, high-resolution XRD results shows that the lattice strain rate caused by neutron irradiation is 6.8%/dpa, while it is only 2.6%/dpa and 4.2%/dpa for Si+ and C+ irradiations respectively. Our results illustrate that the total disorder in neutron irradiated SiC can be accurately simulated by MeV Si+ or C+ irradiations at the same dose, but for the lattice strain and strain-related properties like surface hardness, the depth profile of irradiation damages induced by energetic ions must be considered. This research will contribute to a better understanding of the difference in irradiation effects between neutron and heavy ions.

  16. Subsurface and transcutaneous Raman spectroscopy, imaging, and tomography

    Science.gov (United States)

    Schulmerich, Matthew V.

    Light scattering prevents the direct chemical monitoring of tissue and turbid materials, making it difficult to obtain accurate chemical information. We have developed novel fiber optic Raman probes for biomedical applications that are capable of recovering Raman spectra through several millimeters of overlying turbid materials such as skin, muscle, and adipose tissue. This is accomplished by spatially separating the region that is illuminated from the collection fields of view. In light scattering systems, this spatial separation emphasizes signal originating from below the surface of the scattering material. Engineering polymers and animal models have been used to investigate the depths at which accurate Raman spectrum recovery is achievable and to demonstrate the preservation of spatial information. Using these novel fiber optic probe configurations we have recovered accurate Raman spectra of bone tissue through 5 mm of overlying tissue; we have validated our measurements in vivo and demonstrated Raman tomography for the first time.

  17. Enhancement of the Rate Capability of LiFePO4 by a New Highly Graphitic Carbon-Coating Method.

    Science.gov (United States)

    Song, Jianjun; Sun, Bing; Liu, Hao; Ma, Zhipeng; Chen, Zhouhao; Shao, Guangjie; Wang, Guoxiu

    2016-06-22

    Low lithium ion diffusivity and poor electronic conductivity are two major drawbacks for the wide application of LiFePO4 in high-power lithium ion batteries. In this work, we report a facile and efficient carbon-coating method to prepare LiFePO4/graphitic carbon composites by in situ carbonization of perylene-3,4,9,10-tetracarboxylic dianhydride during calcination. Perylene-3,4,9,10-tetracarboxylic dianhydride containing naphthalene rings can be easily converted to highly graphitic carbon during thermal treatment. The ultrathin layer of highly graphitic carbon coating drastically increased the electronic conductivity of LiFePO4. The short pathway along the [010] direction of LiFePO4 nanoplates could decrease the Li(+) ion diffusion path. In favor of the high electronic conductivity and short lithium ion diffusion distance, the LiFePO4/graphitic carbon composites exhibit an excellent cycling stability at high current rates at room temperature and superior performance at low temperature (-20 °C).

  18. Dynamic Thomson Scattering from Nonlinear Electron Plasma Waves in a Raman Plasma Amplifier

    Science.gov (United States)

    Davies, A.; Katz, J.; Bucht, S.; Haberberger, D.; Bromage, J.; Zuegel, J. D.; Froula, D. H.; Trines, R.; Bingham, R.; Sadler, J.; Norreys, P. A.

    2016-10-01

    Electron plasma waves (EPW's) can be used to transfer significant energy from a long-pulse laser to a short-pulse seed laser through the Raman scattering instability. Successful implementation of Raman amplification could open an avenue to producing high-intensity pulses beyond the capabilities of current laser technology ( 1022 W / cm 2). This three-wave interaction takes advantage of the plasma's ability to sustain large-amplitude plasma waves. Having complete knowledge of the EPW amplitude is essential to establishing optimal parameters for high-efficiency Raman amplification. A dynamic Thomson-scattering diagnostic is being developed to spatially and temporally resolve the amplitude of the driven and thermal EPW's. By imaging the scattered probe light onto a novel pulse-front tilt compensated streaked optical spectrometer, the diffraction efficiency of this plasma wave can be measured as a function of space and time. These data will be used in conjunction with particle-in-cell simulations to determine the EPW's spatial and temporal profile. This will allow the effect of the EPW profile on Raman scattering to be experimentally determined. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  19. A high-stability scanning tunneling microscope achieved by an isolated tiny scanner with low voltage imaging capability

    Science.gov (United States)

    Wang, Qi; Hou, Yubin; Wang, Junting; Lu, Qingyou

    2013-11-01

    We present a novel homebuilt scanning tunneling microscope (STM) with high quality atomic resolution. It is equipped with a small but powerful GeckoDrive piezoelectric motor which drives a miniature and detachable scanning part to implement coarse approach. The scanning part is a tiny piezoelectric tube scanner (industry type: PZT-8, whose d31 coefficient is one of the lowest) housed in a slightly bigger polished sapphire tube, which is riding on and spring clamped against the knife edges of a tungsten slot. The STM so constructed shows low back-lashing and drifting and high repeatability and immunity to external vibrations. These are confirmed by its low imaging voltages, low distortions in the spiral scanned images, and high atomic resolution quality even when the STM is placed on the ground of the fifth floor without any external or internal vibration isolation devices.

  20. Capability of the HAWC gamma-ray observatory for the indirect detection of ultra-high energy neutrinos

    CERN Document Server

    Vargas, Hermes León; Belmont, Ernesto; Alfaro, Rubén

    2016-01-01

    The detection of ultra-high energy neutrinos, with energies in the PeV range or above, is a topic of great interest in modern astroparticle physics. The importance comes from the fact that these neutrinos point back to the most energetic particle accelerators in the Universe, and provide information about their underlying acceleration mechanisms. Atmospheric neutrinos are a background for these challenging measurements, but their rate is expected to be negligible above $\\approx$ 1 PeV. In this work we describe the feasibility to study ultra-high energy neutrinos based on the Earth-skimming technique, by detecting the charged leptons produced in neutrino-nucleon interactions in a high mass target. We propose to detect the charged leptons, or their decay products, with the recently inaugurated High Altitude Water Cherenkov (HAWC) observatory, and use as a large mass target for the neutrino interactions the Pico de Orizaba volcano, the highest mountain in Mexico. In this work we develop an estimate of the detect...

  1. Capability Switching along the Technology Life Cycle in Local Manufacturing within the High-Tech Electronics Industry

    NARCIS (Netherlands)

    H. Brumme (Hendrik)

    2008-01-01

    textabstractResponsible for running a $2.5 billion HP computer factory in a high-cost country like Germany, the author perceived constant pressure defining new manufacturing strategies to keep a competitive advantage for the factory over all internal and external manufacturing alternatives around th

  2. Exploring the Behaviour of Emerging Contaminants in the Water Cycle using the Capabilities of High Resolution Mass Spectrometry.

    Science.gov (United States)

    Hollender, Juliane; Bourgin, Marc; Fenner, Kathrin B; Longrée, Philipp; Mcardell, Christa S; Moschet, Christoph; Ruff, Matthias; Schymanski, Emma L; Singer, Heinz P

    2014-11-01

    To characterize a broad range of organic contaminants and their transformation products (TPs) as well as their loads, input pathways and fate in the water cycle, the Department of Environmental Chemistry (Uchem) at Eawag applies and develops high-performance liquid chromatography (LC) methods combined with high-resolution tandem mass spectrometry (HRMS/MS). In this article, the background and state-of-the-art of LC-HRMS/MS for detection of i) known targets, ii) suspected compounds like TPs, and iii) unknown emerging compounds are introduced briefly. Examples for each approach are taken from recent research projects conducted within the department. These include the detection of trace organic contaminants and their TPs in wastewater, pesticides and their TPs in surface water, identification of new TPs in laboratory degradation studies and ozonation experiments and finally the screening for unknown compounds in the catchment of the river Rhine.

  3. Experimental capabilities of 0.4 PW, 1 shot/min Scarlet laser facility for high energy density science.

    Science.gov (United States)

    Poole, P L; Willis, C; Daskalova, R L; George, K M; Feister, S; Jiang, S; Snyder, J; Marketon, J; Schumacher, D W; Akli, K U; Van Woerkom, L; Freeman, R R; Chowdhury, E A

    2016-06-10

    We report on the recently completed 400 TW upgrade to the Scarlet laser at The Ohio State University. Scarlet is a Ti:sapphire-based ultrashort pulse system that delivers >10  J in 30 fs pulses to a 2 μm full width at half-maximum focal spot, resulting in intensities exceeding 5×1021  W/cm2. The laser fires at a repetition rate of once per minute and is equipped with a suite of on-demand and on-shot diagnostics detailed here, allowing for rapid collection of experimental statistics. As part of the upgrade, the entire laser system has been redesigned to facilitate consistent, characterized high intensity data collection at high repetition rates. The design and functionality of the laser and target chambers are described along with initial data from commissioning experimental shots.

  4. Capabilities for measuring physiocochemical properties at high pressure. [Up to 2000/sup 0/C and 30 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Heard, H.C.; Duba, A.

    1978-02-09

    A group of high-pressure systems that measure physicochemical properties of various media up to 2000/sup 0/C and 30 GPa is described. With these systems it is possible to determine complete stress-strain behavior, ultrasonic velocities, permeability, phase studies, fracture-flow behavior, and optical and electrical properties. The apparatus is described in terms of published results, photographs, and schematic diagrams. 63 references.

  5. Site-specific growth of Au-Pd alloy horns on Au nanorods: A platform for highly sensitive monitoring of catalytic reactions by surface enhancement raman spectroscopy

    KAUST Repository

    Huang, Jianfeng

    2013-06-12

    Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using high-resolution electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd and identified that the horns are bound with high-index {11l} (0.25 < l < 0.43) facets. With an electron beam probe, we visualized the distribution of surface plasmon over the HIF-AuNR@AuPd nanorods, finding that strong longitudinal surface plasmon resonance concentrated at the rod ends. This unique crystal morphology led to the coupling of high catalytic activity with a strong SERS effect at the rod ends, making HIF-AuNR@AuPd an excellent bifunctional platform for in situ monitoring of surface catalytic reactions. Using the hydrogenation of 4-nitrothiophenol as a model reaction, we demonstrated that its first-order reaction kinetics could be accurately determined from this platform. Moreover, we clearly identified the superior catalytic activity of the rod ends relative to that of the rod bodies, owing to the different SERS activities at the two positions. In comparison with other reported Au-Pd bimetallic nanostructures, HIF-AuNR@AuPd offered both higher catalytic activity and greater detection sensitivity. © 2013 American Chemical Society.

  6. Crystal Growth and Electronic Raman Scattering Study of Model High-Tc Cuprate HgBa2 CaCu2 O6 +Ä

    Science.gov (United States)

    Wang, Lichen; Li, Yuan; Luo, Xiangpeng; Li, Jiarui; Yuan Li's Group in ICQM Team

    In this talk, I will report our recent progress on crystal growth of HgBa2CaCu2O6 +x (Hg1212), which possesses a simple tetragonal crystal structure and the highest ambient-pressure Tc (128 K) among all cuprate superconductors with two CuO2 sheets in the primitive cell. Improvement in single-crystal synthesis was made possible by using self-designed high-pressure furnaces and a two-layer encapsulation method, and we demonstrate that the hole concentration can be homogeneously tuned in the underdoped region by post-growth annealing. Our electronic Raman scattering experiments reveal that the maximum of the d-wave superconducting gap increases from single-layer HgBa2CuO4 +x to double-layer Hg1212. In the same spectra, it is found that the characteristic energy of spin excitations, as manifested by the energy of the two-magnon signal, also increases in a nearly proportional fashion. This result is consistent with the idea that magnetic interactions are closely related to the Cooper pairing mechanism.

  7. Raman evidence for presence of high-temperature ferromagnetic clusters in magnetodielectric compound Ba-doped La2NiMnO6

    Science.gov (United States)

    Barbosa, D. A. B.; Paschoal, C. W. A.

    2017-10-01

    Magnetodielectric ferromagnetic semiconductors are key materials because of their applications in spintronic devices; they can be used to control the magnetic properties by applying electric fields. La2NiMnO6 emerged as an important magnetodielectric ferromagnetic semiconductor because of its high Curie temperature near room temperature. Recently Ba doped was successfully used to improve magnetic properties in La2NiMnO6, originating partially ordered systems with different ordering degrees but presenting same Tc = 280 K. However, the influence of Ba doping on the temperature dependent vibrational properties of the system was not investigated. To investigate the Ba doping influence on temperature dependent phonon spectra in La2NiMnO6, we used Raman Spectroscopy to probe the symmetric stretching mode behavior in the range from 10 to 600 K. Remarkable softenings were detected in the phonon behavior due to spin phonon coupling, at several different temperatures, much above Tc. The FWHM dependence with temperature rules out magnetostriction effects. The phonon softenings are the largest reported so far for the RE2NiMnO6 systems and also indicate that Ba doping induces ordering in the Ni/Mn sites. The temperature discordance in characteristic softening onset of the spin phonon coupling are related to ferromagnetic short range clusters due the presence of Ni3 +, Mn3 + oxidation states.

  8. Commercial intermediate pressure MALDI ion mobility spectrometry mass spectrometer capable of producing highly charged laserspray ionization ions.

    Science.gov (United States)

    Inutan, Ellen D; Wang, Beixi; Trimpin, Sarah

    2011-02-01

    The first examples of highly charged ions observed under intermediate pressure (IP) vacuum conditions are reported using laser ablation of matrix/analyte mixtures. The method and results are similar to those obtained at atmospheric pressure (AP) using laserspray ionization (LSI) and/or matrix assisted inlet ionization (MAII). Electrospray ionization (ESI), LSI, and MAII are methods operating at AP and have been shown, with or without the use of a voltage or a laser, to produce highly charged ions with very similar ion abundance and charge states. A commercial matrix-assisted laser desorption/ionization ion mobility spectrometry (IMS) mass spectrometry (MS) instrument (SYNAPT G2) was used for the IP developments. The necessary conditions for producing highly charged ions of peptides and small proteins at IP appear to be a pressure drop region and the use of suitable matrixes and laser fluence. Ionization to produce these highly charged ions under the low pressure conditions of IP does not require specific heating or a special inlet ion transfer region. However, under the current setup, ubiquitin is the highest molecular weight protein observed. These findings are in accord with the need to provide thermal energy in the pressure drop region, similar to LSI and MAII, to improve sensitivity and extend the types of compounds that produce highly charged ions. The practical utility of IP-LSI in combination with IMS-MS is demonstrated for the analysis of model mixtures composed of a lipid, peptides, and a protein. Further, endogenous multiply charged peptides are observed directly from delipified mouse brain tissue with drift time distributions that are nearly identical in appearance to those obtained from a synthesized neuropeptide standard analyzed by either LSI- or ESI-IMS-MS at AP. Efficient solvent-free gas-phase separation enabled by the IMS dimension separates the multiply charged peptides from lipids that remained on the delipified tissue. Lipid and peptide

  9. Raman scattering in crystals

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.F.

    1988-09-30

    A tutorial presentation is given of Raman scattering in crystals. The physical concepts are emphasized rather than the detailed mathematical formalism. Starting with an introduction to the concepts of phonons and conservation laws, the effects of photon-phonon interactions are presented. This interaction concept is shown for a simple cubic crystal and is extended to a uniaxial crystal. The correlation table method is used for determining the number and symmetry of the Raman active modes. Finally, examples are given to illustrate the relative ease of using this group theoretical method and the predictions are compared with measured Raman spectra. 37 refs., 17 figs., 6 tabs.

  10. Molecular-level investigation on electrochemical interfaces by Raman spectroscopy

    Institute of Scientific and Technical Information of China (English)

    TIAN, Zhong-Qun; REN, Bin

    2000-01-01

    The structure and dynamics of electrode/liquid interfaces play an increasingly important role in electrochemistry. Raman spectroscopy is capable of providing detailed structural information at molecular level and new insight into the interfacial structure, adsorption, reaction, electrocatalysis and corrosion. In this account we will summarize some progresses of surface Raman spectroscopy in the study of electrochemical interfaces, mainly based on our group's work, laying emphasis on the detection sensitivity, spectral resolution, time resolution and spatial resolution as well as the hyphenated technique.

  11. Discovering Hidden Painted Images: Subsurface Imaging Using Microscale Spatially Offset Raman Spectroscopy.

    Science.gov (United States)

    Botteon, Alessandra; Conti, Claudia; Realini, Marco; Colombo, Chiara; Matousek, Pavel

    2017-01-03

    We demonstrate for the first time the mapping capability of micro-spatially offset Raman spectroscopy (micro-SORS). The technique enables to form noninvasive images of thin sublayers through highly turbid overlayers. The approach is conceptually demonstrated on recovering overpainted images in situations where conventional Raman microscopy was unable to visualize the sublayer. The specimens mimic real situations encountered in Cultural Heritage that deal, for example, with hidden paintings vandalized with graffiti or covered by superimposed painted layers or whitewash. Additionally, using a letter as a hidden image, we demonstrated the micro-SORS potential to reconstruct also a hidden writing covered, for example, with paper sheets that cannot be easily removed. Potential applications could also include other disciplines such as polymers, biological, catalytic, and forensic sciences where thin, highly turbid layers mask chemically distinct subsurface structures.

  12. Isolation and characterization of Sphingomonas sp. Y2 capable of high-efficiency degradation of nonylphenol polyethoxylates in wastewater.

    Science.gov (United States)

    Bai, Naling; Wang, Sheng; Abuduaini, Rexiding; Zhu, Xufen; Zhao, Yuhua

    2016-06-01

    Nonylphenol polyethoxylates (NPEOs), although banned for decades, are still widely used in manufactories and thus affect human lives. In this study, a highly efficient NPEO-degrading bacterium, Sphingomonas sp. Y2, was isolated from sewage sludge by enrichment culture. Strain Y2 ensured the complete removal of NPEO in 48 h and degraded 99.2 % NPEO (1,000 mg L(-1)) within 30 h at a specific growth rate of 0.73 h(-1) in minimum salt medium. To date, this degradation efficiency is the highest reported for NPEO metabolism by a pure bacterium under this condition. Furthermore, the application of this bacterium to wastewater treatment demonstrated that it metabolized 98.5 % NPEO (1,000 mg L(-1)) within 5 days with a specific growth rate of 2.03 day(-1). The degradation intermediates, identified as nonylphenol, short-chain NPEOs and short-chain nonylphenol polyethoxycarboxylates by high-performance liquid chromatography and gas chromatography-mass spectrometry, indicated the sequential exo-cleavage of the EO chain. Additionally, the enzymes involved in the biodegradation were inducible rather than constitutive. Considering that strain Y2 exhibits prominent biodegradation advantages in industrial wastewater treatment, it might serve as a promising potential candidate for in situ bioremediation of contamination by NPEOs and other structurally similar compounds.

  13. Surface-enhanced raman spectroscopy substrate for arsenic sensing in groundwater

    Science.gov (United States)

    Yang, Peidong; Mulvihill, Martin; Tao, Andrea R.; Sinsermsuksakul, Prasert; Arnold, John

    2015-06-16

    A surface-enhanced Raman spectroscopy (SERS) substrate formed from a plurality of monolayers of polyhedral silver nanocrystals, wherein at least one of the monolayers has polyvinypyrrolidone (PVP) on its surface, and thereby configured for sensing arsenic is described. Highly active SERS substrates are formed by assembling high density monolayers of differently shaped silver nanocrystals onto a solid support. SERS detection is performed directly on this substrate by placing a droplet of the analyte solution onto the nanocrystal monolayer. Adsorbed polymer, polyvinypyrrolidone (PVP), on the surface of the nanoparticles facilitates the binding of both arsenate and arsenite near the silver surface, allowing for highly accurate and sensitive detection capabilities.

  14. Raman lasing in a hollow, bottle-like microresonator

    CERN Document Server

    Ooka, Yuta; Ward, Jonathan; Chromaic, Síle Nic

    2015-01-01

    We report on the fabrication of an ultrahigh quality factor, bottle-like microresonator from a hollow microcapillary, and the realisation of Raman lasing therein at pump wavelengths of $1.55~\\mathrm{\\mu m}$ and $780~\\mathrm{nm}$. Third-order cascaded Raman lasing was observed when pumped at $780~\\mathrm{nm}$. The aerostatic pressure tunability of the Raman laser was also investigated. Thence, we demonstrate that a high dynamic range, high resolution pressure sensor can be realised using the Raman spectrum of the hollow, bottle-like microresonator.

  15. High-Pressure-High Temperature (HP-HT) Stability of Polytetrafluoroethylene: Raman Spectroscopic Study Up to 10 GPa and 600 ℃.

    Science.gov (United States)

    Likhacheva, Anna Yu; Chanyshev, Artem D; Goryainov, Sergey V; Rashchenko, Sergey V; Litasov, Konstantin D

    2017-08-01

    The increasing demand for use of polymers at extreme conditions makes important the exploration of their behavior in a wide pressure and temperature range, which remains unknown for polytetrafluoroethylene (PTFE), one of the most common materials. An in situ Raman spectroscopic study of PTFE shows that it is stable within the range of 2-6 GPa at 500 ℃ and up to 12 GPa at 400 ℃. At T > 500 ℃ and P > 3.5 GPa, the graphitization of PTFE is observed, but judging from the preservation of liquid run products, PTFE can be used as a material for sample container up to 600 ℃ at this pressure. The obtained data allow the suggestion that the triple point between liquid, solid, and decomposed (carbonized) PTFE is located between 3 and 4 GPa at about 550 ℃, by analogy with the behavior of polycyclic aromatic hydrocarbons.

  16. MoO2-ordered mesoporous carbon hybrids as anode materials with highly improved rate capability and reversible capacity for lithium-ion battery.

    Science.gov (United States)

    Chen, Ailian; Li, Caixia; Tang, Rui; Yin, Longwei; Qi, Yongxin

    2013-08-28

    A novel hybrid of MoO2-ordered mesoporous carbon (MoO2-OMC) was prepared through a two-step solvothermal chemical reaction route. The electrochemical performances of the mesoporous MoO2-OMC hybrids were examined using galvanostatical charge-discharge, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS) techniques. The MoO2-OMC hybrid exhibits significantly improved electrochemical performance of high reversible capacity, high-rate capability, and excellent cycling performance as an anode electrode material for Li ion batteries. It is revealed that the MoO2-OMC hybrid could deliver the first discharge capacity of 1641.8 mA h g(-1) with an initial Coulombic efficiency of 63.6%, and a reversible capacity as high as 1049.1 mA h g(-1) even after 50 cycles at a current density of 100 mA g(-1), much higher than the theoretical capacity of MoO2 (838 mA h g(-1)) and OMC materials. The MoO2-OMC hybrid demonstrates an excellent high rate capability with capacity of ∼600 mA h g(-1) even at a charge current density of 1600 mA g(-1) after 50 cycles, which is approximately 11.1 times higher than that of the OMC (54 mA h g(-1)) materials. The improved rate capability and reversible capacity of the MoO2-OMC hybrid are attributed to a synergistic reaction between the MoO2 nanoparticles and mesoporous OMC matrices. It is noted that the electrochemical performance of the MoO2-OMC hybrid is evidently much better than the previous MoO2-based hybrids.

  17. Development and characterization of two human triple-negative breast cancer cell lines with highly tumorigenic and metastatic capabilities.

    Science.gov (United States)

    Su, Yanrong; Pogash, Thomas J; Nguyen, Theresa D; Russo, Jose

    2016-03-01

    Triple-negative breast cancer (TNBC) is a group of cancer with high diversity, limited therapies, and poor prognosis. TNBC cell lines and animal models provide effective tools for studies and drug discovery. Here, we report the development of two TNBC cell lines (XtMCF and LmMCF) based on our existing cell model that consists of normal breast epithelial cell line MCF10F, estradiol-transformed cells trMCF, and Boyden chamber-selected tumorigenic cells bsMCF. The XtMCF and LmMCF cell line were derived from xenograft and lung metastasis of bsMCF cells, respectively. The bsMCF, XtMCF, and LmMCF cells have undergone epithelial-mesenchymal transition (EMT), exhibiting a mesenchymal-like feature. In vivo studies showed XtMCF and LmMCF cells were highly tumorigenic and metastatic. The injection of 5 × 10(4) cells to CB17/SCID mice mammary fat pad produced xenografts in 9/9 mice and tumors reached 10 millimeters in diameter in 5 weeks. The injection of 1 × 10(6) XtMCF or 8 × 10(4) LmMCF cells into the mice tail vein was sufficient to form extensive lung metastases in 4 weeks. The two new cell lines exhibited CD44(+) /CD49f(+) and CD44(+) /EpCAM(+) cancer stem cell (CSC) characteristics, and the EGF-like domain of EpCAM was cleaved off. Together with the normal and early transformed counterparts, herein we provide a complete cancer model for the study of initiation, evolution, and identification of new therapeutics for TNBC. The finding that EGF-like domain of EpCAM was cleaved off in cells which have undergone EMT suggests this cleavage may be involved in the EMT process and the cancer stem cell properties of these cells.

  18. Comparison between Double Crystals X-ray Diffraction and Micro-Raman Measurement on Composition Determination of High Ge Content Si1-xGex Layer Epitaxied on Si Substrate

    Institute of Scientific and Technical Information of China (English)

    Lei ZHAO; Yuhua ZUO; Buwen CHENG; Jinzhong YU; Qiming WANG

    2006-01-01

    It is important to acquire the composition of Si1-xGex layer, especially that with high Ge content, epitaxied on Si substrate. Two nondestructive examination methods, double crystals X-ray diffraction(DCXRD)and micro-Raman measurement, were introduced comparatively to determine x value in Si1-xGex layer, which show that while the two methods are consistent with each other when x is low, the results obtained from double crystals X-ray diffraction are not credible due to the large strain relaxation occurring in Si1-xGex layers when Ge content is higher than about 20%. Micro-Raman measurement is more appropriate for determining high Ge content than DCXRD.

  19. Synthesis and electrochemical characterization of stoichiometric Cu2S as cathode material with high rate capability for rechargeable lithium batteries

    Science.gov (United States)

    Kalimuldina, Gulnur; Taniguchi, Izumi

    2016-11-01

    Synthesis of stoichiometric copper sulfide (Cu2S) was studied by spray pyrolysis (SP) with heat treatment for different Cu/S molar ratios in the starting solution and different synthesis and annealing temperatures. The sample prepared via SP at 400 °C and then annealed at 460 °C for 2 h showed the stoichiometric Cu/S ratio, which was verified by inductively coupled plasma-optical emission spectroscopy. The X-ray diffraction (XRD) peaks of the sample were indexed to the monoclinic structure with space group P21/c. The electrochemical performance of the stoichiometric Cu2S electrode was investigated by a cycle test and differential capacity analysis. The Cu2S electrode coated on an Al foil exhibited a first discharge capacity of 335 mAh g-1 at a charge-discharge rate of 0.1 C, which corresponds to 99.4% of its theoretical capacity. However it showed poor reversibility owing to the corrosion of Al foil by Cu. In contrast, the Cu2S electrode coated on Cu foil demonstrated stable cyclability at high charge-discharge rates of up to 30 C. Exsitu XRD analysis showed that a phase transformation from the monoclinic Cu2S structure with the space group P21/c to the tetragonal Cu1.96S structure with the space group P43212 gradually progressed during the initial five cycles.

  20. Formation of nickel-doped magnetite hollow nanospheres with high specific surface area and superior removal capability for organic molecules

    Science.gov (United States)

    Li, Zhenhu; Ma, Yurong; Qi, Limin

    2016-12-01

    A strategy for the formation of magnetic Ni x Fe3-x O4 hollow nanospheres with very high specific surface areas was designed through a facile solvothermal method in mixed solvents of ethylene glycol and water in this work. The Ni/Fe ratios and the crystal phases of the Ni x Fe3-x O4 hollow nanocrystals can be readily tuned by changing the molar ratios of Ni to Fe in the precursors. An inside-out Ostwald ripening mechanism was proposed for the formation of uniform Ni x Fe3-x O4 hollow nanospheres. Moreover, the obtained Ni x Fe3-x O4 hollow nanospheres exhibited excellent adsorption capacity towards organic molecules such as Congo red in water. The maximum adsorption capacities of Ni x Fe3-x O4 hollow nanospheres for Congo red increase dramatically from 263 to 500 mg g-1 with the increase of the Ni contents (x) in Ni x Fe3-x O4 hollow nanospheres from 0.2 to 0.85. The synthesized Ni x Fe3-x O4 nanoparticles can be potentially applied for waste water treatment.