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Sample records for opals

  1. Template-synthesized opal hydrogels

    Institute of Scientific and Technical Information of China (English)

    LI Jun; JI Lijun; RONG Jianhua; YANG Zhenzhong

    2003-01-01

    Opal hydrogels could be synthesized with polymer inverse opal template. A pH responsive opal N-iso- propylacrylamide/acrylic acid copolymerized hydrogel was prepared as an example. The ordered structure and response to pH were investigated. Through the sol-gel process of tetrabutyl titanate, opal titania was obtained with the opal hydrogel template.

  2. OPAL Muon Chamber

    CERN Multimedia

    OPAL was one of the 4 experiments installed at the LEP particle accelerator from 1989 to 2000. This is a slice of the outermost layer of OPAL : the muon chambers. This outside layer detects particles which are not stopped by the previous layers. These are mostly muons.

  3. OPAL Silicon Tungsten Luminometer

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The Silicon Tungsten Luminometer was part of OPAL's calorimeter which was used to measure the energy of particles. Most particles end their journey in calorimeters. These detectors measure the energy deposited when particles are slowed down and stopped.

  4. OPAL detector electromagnetic calorimeter

    CERN Multimedia

    1988-01-01

    Half of the electromagnetic calorimeter of the OPAL detector is seen in this photo. This calorimeter consists of 4720 blocks of lead glass. It was used to detect and measure the energy of photons, electrons and positrons by absorbing them.

  5. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  6. Synthetic magnetic opals

    Indian Academy of Sciences (India)

    Amita Gupta; Alexei Yu Ganin; Parmanand Sharma; Vikrant Agnihotri; L M Belova; K V Rao; Mikhail E Kozlov; A A Zakhidov; R H Baughman

    2002-05-01

    We present studies of novel nanocomposites of BiNi impregnated into the structure of opals as well as inverse opals. Atomic force microscopy and high resolution elemental analyses show a highly ordered structure and uniform distribution of the BiNi filler in the matrix. These BiNi-based nanocomposites are found to exhibit distinct ferromagnetic-like ordering with transition temperature of about 675 K. As far as we know there exists no report in literature on any BiNi compound which is magnetic.

  7. OPAL and More

    CERN Document Server

    Giacomelli, G

    2009-01-01

    We shall summarize some of the research activities performed in collaboration with Ben Shen in the OPAL experiment at LEP and in the CMS experiment at the LHC. And we shall recall the LEP legacy to particle physics in general and to the Standard Model in particular. Short recollections are made in other fields in which Ben was interested, in particular in Astroparticle Physics.

  8. Dismantling OPAL's cylindrical magnet core

    CERN Multimedia

    Laurent Guiraud

    2001-01-01

    Lifting a handling device for dismounting the pressure bells, which are inside the cylindrical magnet coil on the central section of OPAL, on the right part of the photo. OPAL was a detector on the LEP accelerator, which ran from 1989 to 2000.

  9. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  10. The OPAL reactor

    Energy Technology Data Exchange (ETDEWEB)

    Miller, R.; Irwin, T. [Australian Nuclear Science and Technology Organisation, Sydney (Australia); Ordonez, J.P. [INVAP SE, Bariloche (Argentina)

    2007-07-01

    The project to provide a replacement for Australia's HIFAR reactor began with governmental approval in September 1997 and reached its latest milestone with the achievement of the first full power operation of the OPAL reactor in November 2006. OPAL is a pool-type reactor with a thermal power of 20 MW and a fuel enrichment maximum of 20 per cent. This has been a successful project for both ANSTO (Australian Nuclear Science and Technology Organisation) and the contractor INVAP SE. This project was characterised by extensive interaction with the project's stake-holders during project definition and the use of a performance-based turnkey contract which gave the contractor the maximum opportunity to optimise the design to achieve performance and cost effectiveness. The contactor provided significant in-house resources as well as capacity to manage an international team of suppliers and sub-contractors. A key contributor to the project's successful outcomes has been the development and maintenance of an excellent working relationship between ANSTO and INVAP project teams. Commissioning was undertaken in accordance with the IAEA recommended stages. This paper presents the approaches used to define the project requirements, to choose the supplier and to deliver the project. The main results of hot commissioning are reviewed and the problems encountered examined. Operational experience since hot commissioning is also reviewed.

  11. Biocompatibility of crystalline opal nanoparticles

    Directory of Open Access Journals (Sweden)

    Hernández-Ortiz Marlen

    2012-10-01

    Full Text Available Abstract Background Silica nanoparticles are being developed as a host of biomedical and biotechnological applications. For this reason, there are more studies about biocompatibility of silica with amorphous and crystalline structure. Except hydrated silica (opal, despite is presents directly and indirectly in humans. Two sizes of crystalline opal nanoparticles were investigated in this work under criteria of toxicology. Methods In particular, cytotoxic and genotoxic effects caused by opal nanoparticles (80 and 120 nm were evaluated in cultured mouse cells via a set of bioassays, methylthiazolyldiphenyl-tetrazolium-bromide (MTT and 5-bromo-2′-deoxyuridine (BrdU. Results 3T3-NIH cells were incubated for 24 and 72 h in contact with nanocrystalline opal particles, not presented significant statistically difference in the results of cytotoxicity. Genotoxicity tests of crystalline opal nanoparticles were performed by the BrdU assay on the same cultured cells for 24 h incubation. The reduction of BrdU-incorporated cells indicates that nanocrystalline opal exposure did not caused unrepairable damage DNA. Conclusions There is no relationship between that particles size and MTT reduction, as well as BrdU incorporation, such that the opal particles did not induce cytotoxic effect and genotoxicity in cultured mouse cells.

  12. Thermoelectric properties of inverse opals

    Science.gov (United States)

    Mahan, G. D.; Poilvert, N.; Crespi, V. H.

    2016-02-01

    Rayleigh's method [Philos. Mag. Ser. 5 34, 481 (1892)] is used to solve for the classical thermoelectric equations in inverse opals. His theory predicts that in an inverse opal, with periodic holes, the Seebeck coefficient and the figure of merit are identical to that of the bulk material. We also provide a major revision to Rayleigh's method, in using the electrochemical potential as an important variable, instead of the electrostatic potential. We also show that in some cases, the thermal boundary resistance is important in the effective thermal conductivity.

  13. OPAL 96 Blocks Lead Glass

    CERN Multimedia

    This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. One half of the complete calorimeter is shown in the picture above. There were 9440 lead glass counters in the OPAL electromagnetic calorimeter. These are made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP interactions.

  14. Dating fossil opal phytoliths

    Energy Technology Data Exchange (ETDEWEB)

    Lentfer, C.; Boyd, B. [Southern Cross University, Lismore, NSW (Australia). School of Resource Science and Management; Torrence, R. [Australian Museum, Sydney, NSW (Australia). Division of Anthropology

    1999-11-01

    Full text: Opal phytoliths are microscopic silica bodies formed by the precipitation of hydrated silica dioxide (SiO{sub 2}nH{sub 2}0) in, around and between cell walls. They are relatively resistant to degradation in most environments and thus, can occur in large quantities in palaeosediments. Consequently, they are valuable tools for environmental reconstruction. Furthermore, phytoliths are often the only recoverable organic material in well oxidised sediments, the occluded carbon provides the opportunity for dating sediment whose ages have previously been difficult to determine, and thus, increase the potential for fine resolution determination of environmental change. This poster describes the results of an investigation assessing the viability of AMS radiocarbon dating of fossil phytolith inclusions using samples from Garua Island, West New Britain, PNG. Thirteen phytolith samples, isolated from sediments previously dated using tephrastratigraphy and C14 dating of macroremains of nutshells and wood charcoal, were used in the analysis. As a control measure, thirteen parallel samples of microscopic charcoal were also dated using AMS. The results show that the AMS dates for the microscopic charcoal samples are consistent with ages anticipated from the other dating methods, for all but one sample. However, the dates for eight of the thirteen phytolith samples are considerably younger than expected. This bias could be explained by several factors, including downwashing of phytolith through soils, bioturbation, carbon exchange through the siliceous matrix of the phytolith bodies, and contamination from extraneous sources of modern carbon retained in the samples. Research is currently focusing on the investigation of these issues and selected samples are in the process of being retreated with strong oxidising agents to clear contaminants prior to re-dating. Further to this, a full investigation of one profile with a long sequence is underway. High concentrations of

  15. OPAL Example Segment of Silicon Tungsten Luminometer

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. The Silicon Tungsten Luminometer was part of OPAL's calorimeter which was used to measure the energy of particles. Most particles end their journey in calorimeters. These detectors measure the energy deposited when particles are slowed down and stopped.

  16. Lagrangian modelling of OPALE dataset.

    Science.gov (United States)

    Gil, Jaime E.; Thomas, Jennie; Bekki, Slimane; Kukui, Alexandre; Ancellet, Gerad; Preunkert, Susanne; Legrand, Michel; Frey, Markus; Savarino, Joel; Jourdain, Bruno; Kerbrat, Michel; France, James; King, Martin; Toumi, Ralf

    2013-04-01

    The OPALE measurement campaign aimed to characterize the atmospheric chemistry of the East Antarctic Plateau making a range of measurements at two sites, a coastal one, Dumont d'Urville (DDU) (From December 2010 until March 2011, 66o S, 123oE, coastal site) and on top of the Antarctic plateau Dome C (From December 2011 until January 2012 at Dome C, 75oS, 123o E, 3233 m a.s.l.). There are relatively few observations of chemistry occurring inland and coastal sites Antarctic sites. During the campaign air masses originating from the marine boundary layer, the free troposphere, the Antarctic continent, and of mixed origins were observed. We present analyses of chemical measurements (including O3, NO2, OH, RO2, hydrocarbons) using the CiTTyCAT photochemical trajectory model. The model simulates the chemistry of air masses over multiple (~5) days back trajectories provided by a stochastic trajectory model (FLEXPART). In some cases, the initial chemical conditions are taken from a chemistry-transport model (MOZART). The effect of clouds on the photolysis rates is also accounted for using MODIS satellite data. The model results are compared with measurements performed during both OPALE campaign years. Differences between the reactive nitrogen and hydroxyl radical chemistry at DDU and Dome C and the strong influence of reactive exchanges of trace gases between the snow and the atmosphere at Dome C are highlighted. The implications for the oxidizing capacity of the Antarctic boundary layer are also discussed.

  17. Virgin Valley opal district, Humboldt County, Nevada

    Science.gov (United States)

    Staatz, Mortimer Hay; Bauer, Herman L.

    1951-01-01

    The Virgin Valley opal district, Humboldt County, Nevada, is near the Oregon-Nevada border in the Sheldon Game Refuge. Nineteen claims owned by Jack and Toni Crane were examined, sampled, and tested radiometrically for uranium. Numerous discontinuous layers of opal are interbedded with a gently-dipping series of vitric tuff and ash which is at least 300 ft thick. The tuff and ash are capped by a dark, vesicular basalt in the eastern part of the area and by a thin layer of terrace qravels in the area along the west side of Virgin Valley. Silicification of the ash and tuff has produced a rock that ranges from partly opalized rock that resembles silicified shale to completely altered rock that is entirely translucent, and consists of massive, brown and pale-green opal. Carnotite, the only identified uranium mineral, occurs as fracture coatings or fine layers in the opal; in places, no uranium minerals are visible in the radioactive opal. The opal layers are irregular in extent and thickness. The exposed length of the layers ranges from 8 to 1, 200 ft or more, and the thickness of the layers ranges from 0. 1 to 3. 9 ft. The uranium content of each opal layer, and of different parts of the same layer, differs widely. On the east side of Virgin Valley four of the seven observed opal layers, nos. 3, 4, 5, and 7, are more radioactive than the average; and the uranium content ranges from 0. 002 to 0. 12 percent. Two samples, taken 5 ft apart across opal layer no. 7, contained 0. 003 and 0. -049 percent uranium. On the west side of the valley only four of the fifteen observed opal layers, nos; 9, , 10, 14, and 15, are more radioactive than the average; and the uranium content ranges from 0. 004 to 0. 047 percent. Material of the highest grade was found in a small discontinuous layer of pale-green opal (no. 4) on the east side of Virgin Valley. The grade of this layer ranged from 0. 027 to 0. 12 percent uranium.

  18. Opal shell structures: direct assembly versus inversion approach.

    Science.gov (United States)

    Deng, Tian-Song; Sharifi, Parvin; Marlow, Frank

    2013-09-16

    Opal shell structures can be fabricated in two ways: By direct assembly from hollow spheres (hs-opal) or by infiltration of precursors into opal templates and inversion. The resulting lattice disturbances were characterized by scanning electron microscopy (SEM), optical microscopy, and transmission spectra. The hs-opal system shows much lower disturbances, for example, a lower number of cracks and lattice deformations. The strong suppression of crack formation in one of these inverse opal structures can be considered as promising candidates for the fabrication of more perfect photonic crystals.

  19. Photonic crystal waveguides in artificial opals

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Kiyan, Roman; Neumeister, Andrei;

    2008-01-01

    3D photonic crystals based on Si inverted-opals are numerically explored as hosts for effective air-channel waveguides, which can serve as parts of photonic circuits. Two basic shapes of straight waveguides are considered: cylindrical and a chain of spheres. Modelling shows that transmission...

  20. The barrel electromagnetic calorimeter on OPAL

    CERN Multimedia

    Patrice Loiez

    1993-01-01

    The two particle beams collide at the centre of this barrel and eject a large number of different particles. The energy of some of these particles will be measured by this electromagnetic calorimeter by absorbing all of the particle's energy. The OPAL detector was used on the LEP accelerator, which ran from 1989 to 2000.

  1. Opal web services for biomedical applications.

    Science.gov (United States)

    Ren, Jingyuan; Williams, Nadya; Clementi, Luca; Krishnan, Sriram; Li, Wilfred W

    2010-07-01

    Biomedical applications have become increasingly complex, and they often require large-scale high-performance computing resources with a large number of processors and memory. The complexity of application deployment and the advances in cluster, grid and cloud computing require new modes of support for biomedical research. Scientific Software as a Service (sSaaS) enables scalable and transparent access to biomedical applications through simple standards-based Web interfaces. Towards this end, we built a production web server (http://ws.nbcr.net) in August 2007 to support the bioinformatics application called MEME. The server has grown since to include docking analysis with AutoDock and AutoDock Vina, electrostatic calculations using PDB2PQR and APBS, and off-target analysis using SMAP. All the applications on the servers are powered by Opal, a toolkit that allows users to wrap scientific applications easily as web services without any modification to the scientific codes, by writing simple XML configuration files. Opal allows both web forms-based access and programmatic access of all our applications. The Opal toolkit currently supports SOAP-based Web service access to a number of popular applications from the National Biomedical Computation Resource (NBCR) and affiliated collaborative and service projects. In addition, Opal's programmatic access capability allows our applications to be accessed through many workflow tools, including Vision, Kepler, Nimrod/K and VisTrails. From mid-August 2007 to the end of 2009, we have successfully executed 239,814 jobs. The number of successfully executed jobs more than doubled from 205 to 411 per day between 2008 and 2009. The Opal-enabled service model is useful for a wide range of applications. It provides for interoperation with other applications with Web Service interfaces, and allows application developers to focus on the scientific tool and workflow development. Web server availability: http://ws.nbcr.net.

  2. Investigation and calculation of filling factor of SnO2 inverse opal

    Science.gov (United States)

    Wang, Jinquan; Wu, Shimin; Ji, Xiaoyuan; Li, Jinpeng; Zhang, Rong; Zhang, Ming

    2016-04-01

    In the process of preparing inverse opal, the structure of inverse opal is affected by many factors, and the filling factor of inverse opal is difficult to directly test. In this paper, SnO2 inverse opal was prepared with the sol-gel method by cooperative opal template. The repetition times of the infiltrating precursor into the opal templates were investigated in detail. The band-gap positions of SnO2 inverse opal were tested. In order to prepare perfect inverse opal structure, the filling quantity of the precursor is greater, as the diameter of the PS microsphere of opal is bigger. The filling factor of air in inverse opal can be calculated with a formula derived from Bragg’s law. For inverse opal, the filling factor of air in inverse opal gradually enlarges as the diameter of the void increases.

  3. Equations for filling factor estimation in opal matrix

    CERN Document Server

    Abrarov, S M; Kim, T W

    2005-01-01

    We consider two equations for the filling factor estimation of infiltrated zinc oxide (ZnO) in silica (SiO2) opal and gallium nitride in ZnO opal. The first equation is based on the effective medium approximation, while the second one - on Maxwell-Garnett approximation. The comparison between two filling factors shows that both equations can be equally used for the estimation of the quantity of infiltrated nanocrystals inside opal matrix.

  4. Formation Process of a TiO2 Inverse Opal

    Institute of Scientific and Technical Information of China (English)

    倪培根; 程丙英; 张道中

    2002-01-01

    Inverse opals of TiO2 with different filling fractions were fabricated by using an opal of polystyrene spheres as a template. Scanning electron microscopy showed the accumulative process of TiO2. The transmission spectra of inverse opals with different filling fractions were measured and the shifts of transmission dip with the filling fraction were observed. Our investigation made the infiltration process clear, and it might be helpful for further improvement of the fabrication of TiO2 inverse opals.

  5. Liquid-impermeable inverse opals with invariant photonic bandgap.

    Science.gov (United States)

    Kang, Hyelim; Lee, Joon-Seok; Chang, Won Seok; Kim, Shin-Hyun

    2015-02-18

    Omniphobic inverse opals are created by structurally and chemically modifying the surface of inverse opals through reactive ion etching. During the etching, void arrays of the inverse opal surface evolves to a triangular post array with re-entrant geometry. The elaborate structure can efficiently pin the air-liquid interface and retain air cavities against water and oil, thereby providing liquid-impermeable inverse opals with invariant photonic bandgap. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Microstructural study of CdS/OPAL composites

    CERN Document Server

    Torrecillas, R; Brito, M E; López, C; Miguez, M; Meseguer, F; Moya, J S

    2000-01-01

    CdS/opal photonic materials have been characterised by transmission electron microscopy. The photonic properties of opals formed by CdS- SiO/sub 2/ nanospheres 380 nm in diameter, face-centred cubic ordered and with different CdS filling factors were studied by means of specular reflectance or transmission spectroscopy. It is shown that CdS semiconductor grows homogeneously in the opal interstices, in a cubic phase, with 24 nm being the microcrystal particle size. We show here that chemical bath deposition (CBD) is a useful method to fill the opal interstices, a crucial step for producing photonic band gap materials. (22 refs).

  7. Carbon Inverse Opal Rods for Nonenzymatic Cholesterol Detection.

    Science.gov (United States)

    Zhong, Qifeng; Xie, Zhuoying; Ding, Haibo; Zhu, Cun; Yang, Zixue; Gu, Zhongze

    2015-11-18

    Carbon inverse opal rods made from silica photonic crystal rods are used for nonenzymatic cholesterol sensing. The characteristic reflection peak originating from the physical periodic structure works as sensing signals for quantitatively estimating cholesterol concentrations. Carbon inverse opal rods work both in cholesterol standard solutions and human serum. They are suitable for practical use in clinical diagnose.

  8. Structural changes of synthetic opal by heat treatment

    Science.gov (United States)

    Arasuna, Akane; Okuno, Masayuki; Okudera, Hiroki; Mizukami, Tomoyuki; Arai, Shoji; Katayama, Shin'ichi; Koyano, Mikio; Ito, Nobuaki

    2013-10-01

    The structural changes of synthetic opal by heat treatment up to 1,400 °C were investigated using scanning electron microscopy, X-ray diffraction, and Fourier transform infrared and Raman spectroscopies. The results indicate that the dehydration and condensation of silanol in opal are very important factors in the structural evolution of heat-treated synthetic opal. Synthetic opal releases water molecules and silanols by heat treatment up to 400 °C, where the dehydration of silanol may lead to the condensation of a new Si-O-Si network comprising a four-membered ring structure of SiO4 tetrahedra, even at 400 °C. Above 600 °C, water molecules are lost and the opal surface and internal silanol molecules are completely dehydrated by heat effect, and the medium-temperature range structure of opal may begin to thermally reconstruct to six-membered rings of SiO4 tetrahedra. Above 1,000 °C, the opal structure almost approaches that of silica glass with an average structure of six-membered rings. Above 1,200 °C, the opal changes to low-cristobalite; however, minor evidence of low-tridymite stacking was evident after heat treatment at 1,400 °C.

  9. Synthesis and photonic bandgap characterization of polymer inverse opals

    Energy Technology Data Exchange (ETDEWEB)

    Miguez, H.; Meseguer, F.; Lopez, C. [Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Inst. de Ciencia de Materiales; Universidad Politecnica de Valencia (Spain). Centro Tecnologico de Ondas; Lopez-Tejeira, F.; Sanchez-Dehesa, J. [Universidad Autonoma de Madrid (Spain). Dept. de Fisica Teorica de la Materia Condensada

    2001-03-16

    Polymer inverse opals with long-range order have been fabricated and their photonic crystal behavior examined. Good agreement between band structure calculations and experiment is found. It is envisaged that these inverse opals could be used for the modification of the electronic properties of incorporated luminescent materials and as matrices for the synthesis of spherical colloidal particles. (orig.)

  10. Barium titanate inverted opals-synthesis, characterization, and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Soten, I.; Miguez, H.; Yang, S.M.; Petrov, S.; Coombs, N.; Tetreault, N.; Ozin, G.A. [Toronto Univ., ON (Canada). Dept. of Chemistry; Matsuura, N.; Ruda, H.E. [Toronto Univ., ON (Canada). Dept. of Metallurgy and Materials Science

    2002-01-01

    The engineering of cubic or tetragonal polymorphs of nanocrystalline barium titanate inverted opals has been achieved by thermally induced transformations. Optical characterization demonstrated photonic crystal behavior of the opals. The tuning of the ferroelectric-paraelectric transition around the Curie temperature is shown in this paper. (orig.)

  11. Trace elements in coloured opals using neutron activation analysis

    Energy Technology Data Exchange (ETDEWEB)

    McOrist, G.D.; Smallwood, A. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

    1996-12-31

    Neutron activation analysis (NAA) is a technique particularly suited to analysing opals since it is non-destructive and the silica matrix of opals is not prone to significant activation. It was used to determine the concentration of trace elements in 50 samples of orange, yellow, green, blue and pink opals as well as 18 samples of colourless opals taken from a number of recognised fields in Australia, Peru, Mexico and USA. The results were then evaluated to determine if a relationship existed between trace element content and opal colour. The mean concentration of most of the elements found in orange, yellow and colourless opals were similar with few exceptions. This indicated that, for these samples, colour is not related to the trace elements present. However, the trace element profile of the green, pink and blue opals was found to be significantly different with each colour having a much higher concentration of certain trace elements when compared with all other opals analysed. 7 refs.

  12. Artificial Opals as Nanophotonic Materials for Optical Communication

    DEFF Research Database (Denmark)

    Lavrinenko, Andrei; Leyrer, R J; Wohlleben, W

    2007-01-01

    We report on advances in the fabrication of thick and homogeneous polymer opals films with bead sizes up to 600 nm; photo-ablation and point and line defect inscription with femtosecond laser pulses; analysis of the influence of imperfections on opal transmission-reflection properties and numeric...

  13. Indium oxide inverse opal films synthesized by structure replication method

    Science.gov (United States)

    Amrehn, Sabrina; Berghoff, Daniel; Nikitin, Andreas; Reichelt, Matthias; Wu, Xia; Meier, Torsten; Wagner, Thorsten

    2016-04-01

    We present the synthesis of indium oxide (In2O3) inverse opal films with photonic stop bands in the visible range by a structure replication method. Artificial opal films made of poly(methyl methacrylate) (PMMA) spheres are utilized as template. The opal films are deposited via sedimentation facilitated by ultrasonication, and then impregnated by indium nitrate solution, which is thermally converted to In2O3 after drying. The quality of the resulting inverse opal film depends on many parameters; in this study the water content of the indium nitrate/PMMA composite after drying is investigated. Comparison of the reflectance spectra recorded by vis-spectroscopy with simulated data shows a good agreement between the peak position and calculated stop band positions for the inverse opals. This synthesis is less complex and highly efficient compared to most other techniques and is suitable for use in many applications.

  14. Tubular inverse opal scaffolds for biomimetic vessels

    Science.gov (United States)

    Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

    2016-07-01

    There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

  15. Measurement of parton shower observables with OPAL

    Science.gov (United States)

    Fischer, N.; Gieseke, S.; Kluth, S.; Plätzer, S.; Skands, P.

    2016-07-01

    A study of QCD coherence is presented based on a sample of about 397,000 e+e- hadronic annihilation events collected at √s = 91 GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions.

  16. Measurement of parton shower observables with OPAL

    Directory of Open Access Journals (Sweden)

    Fischer N.

    2016-01-01

    Full Text Available A study of QCD coherence is presented based on a sample of about 397,000 e+e- hadronic annihilation events collected at √s = 91 GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions.

  17. Inverted opal luminescent Ce-doped silica glasses

    Directory of Open Access Journals (Sweden)

    R. Scotti

    2006-01-01

    Full Text Available Inverted opal Ce-doped silica glasses (Ce : Si molar ratio 1 ⋅ 10−3 were prepared by a sol-gel method using opals of latex microspheres as templates. The rare earth is homogeneously dispersed in silica host matrix, as evidenced by the absence of segregated CeO2, instead present in monolithic Ce-doped SG with the same cerium content. This suggests that the nanometric dimensions of bridges and junctions of the host matrix in the inverted opal structures favor the RE distribution avoiding the possible segregation of CeO2.

  18. Precision luminosity measurement with the OPAL silicon-tungsten calorimeters

    CERN Document Server

    Arcelli, S

    1999-01-01

    A preliminary, high precision measurement of the luminosity of the LEP colliding beams for the LEP I data recorded between 1993 and 1995 with the OPAL experiment is presented, the measurement is based on the OPAL Silicon-Tungten luminosity monitor, which detects electrons from small-angle Bhabha scattering at angles between approximately 25 and 58 mrad. The overall experimental uncertainty on the measured luminosity is 3.3*10/sup -4/. Such uncertainty contributes negligibly to the uncertainty on the OPAL cross section measurements near the Z /sup 0/ resonance. (3 refs).

  19. Optical properties of metallo-dielectric microspheres in opal structures

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y; Whitehouse, C; Li, Jensen; Tam, Wing Yim; Chan, C T; Sheng Ping [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2003-09-03

    We report the fabrication of opal structure using metallo-dielectric silica microspheres. Mono-dispersed silica microspheres were coated with silver using an electrode-less wet-plating technique. Thin slabs of opal were obtained by assembling the silver-coated microspheres between two glass plates using a forced-packing method. The optical properties of the resulting opal structure were studied in the infrared range. Good agreement is obtained with the predictions of a multiple scattering approach, provided that the silver layer is modelled as a silver composite.

  20. Polymer sol-gel composite inverse opal structures.

    Science.gov (United States)

    Zhang, Xiaoran; Blanchard, G J

    2015-03-25

    We report on the formation of composite inverse opal structures where the matrix used to form the inverse opal contains both silica, formed using sol-gel chemistry, and poly(ethylene glycol), PEG. We find that the morphology of the inverse opal structure depends on both the amount of PEG incorporated into the matrix and its molecular weight. The extent of organization in the inverse opal structure, which is characterized by scanning electron microscopy and optical reflectance data, is mediated by the chemical bonding interactions between the silica and PEG constituents in the hybrid matrix. Both polymer chain terminus Si-O-C bonding and hydrogen bonding between the polymer backbone oxygens and silanol functionalities can contribute, with the polymer mediating the extent to which Si-O-Si bonds can form within the silica regions of the matrix due to hydrogen-bonding interactions.

  1. Treating temperature effect on bandgap in polymer opal photonic crystals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The optical reflective spectra and microstruc- tures of polystyrene opal photonic crystals treated with dif- ferent temperatures have been investigated. With tempera- ture increasing, the polystyrene spheres in opal structure transform to dodecahedrons, and the peak of reflective spec- trum moves to shorter wavelength. The experiment result testifies the effect of the effective refractive index and the filling ratio to the bandgap position, and it corresponds to the theoretical simulative result.

  2. Abnormal Modulation of Dielectric Band Transmittance of Polystyrene Opal

    Institute of Scientific and Technical Information of China (English)

    HU Xiao-Yong; GONG Qi-Huang; CHENG Bing-Ying; ZHANG Dao-Zhong

    2005-01-01

    @@ The abnormal transmittance in the dielectric band edge of a polystyrene opal is observed and analysed. The transmittance is periodically modulated and the period of modulation varies with the wavelength, which destroys the perfect structure of the photonic band gap. The transmittance modulation originates from the propagation of the low order whispering-gallery mode excited in polystyrene spheres. These results indicate that the whisperinggallery mode has a great influence on practical applications of polystyrene opal.

  3. Preliminary Results of Occurrence and Mineralogical Properties of Opals from Northwest part of Central Anatolia

    Science.gov (United States)

    Çalık, Ayten

    2016-04-01

    The study area, is located in northwest part of central Anatolian, consists of Eskişehir and Kütahya region where are important for finding occurrence of opaline silica mineralization as well as chalcedonic silica mineralization. In this study preliminary results of mineralogical properties of opals from four different area (Sabuncupınar, Belkavak, Gokçekısık and Derekoy), located between Eskisehir and Kutahya region, have been given. In the Kütahya region, dendritic opal nodules present in Pliocene pyroclastic rocks - Kanoturaǧı hill and white opals outcrop in stockwork veins with serpentinites in Küçükali hill around Sabuncupınar village. The mainly whitish - blue and gray opal nodules range from millimetres in diameter to about five and ten centimetres in Kanoturagı hill. White opals, called milky opal, are white color and present in veins within serpentinites. The Kanoturagı opal is made up of tiny spheres, the milky opal is made up tiny sphere with fibrous texture based on the SEM. Green opals present in Miocene pyroclastic rocks in Belkavak village. The Belkavak opals are greenish color and having a brecciated appearance. Opals outcrops around Sabuncu pınar and Belkavak villages consist of opal - CT, alpha quartz and, moganite, and a lesser amount of opal - C based on the results of XRD analysis. In the Eskişehir region, the dendritic opals occur as nodules in volcanogenetic conglomerates of Pliocene age in the Dereyalak area. The Dereyalak opals vary in size from millimetres in diameter to about ten centimetres. Their color are mainly white, beige, greenish, yellowish orange and black. On the other hand, Pliocene pyroclastic rocks are the host rock of opals in Gökçekısık village - Eskişehir. Gökçekısık Opals are mainly colorless, pale shades of yellow, whitish blue and gray colors and display a reinous to sub vitreous luster. Dereyalak dendiritic opals consist of opal - CT, opal - C and a lesser amount of alpha quartz and, moganite

  4. Particulate inverse opal carbon electrodes for lithium-ion batteries.

    Science.gov (United States)

    Kang, Da-Young; Kim, Sang-Ok; Chae, Yu Jin; Lee, Joong Kee; Moon, Jun Hyuk

    2013-01-29

    Inverse opal carbon materials were used as anodes for lithium ion batteries. We applied particulate inverse opal structures and their dispersion in the formation of anode electrodes via solution casting. We prepared aminophenyl-grafted inverse opal carbons (a-IOC), inverse opal carbons with mesopores (mIOC), and bare inverse opal carbons (IOC) and investigated the electrochemical behavior of these samples as anode materials. Surface modification by aminophenyl groups was confirmed by XPS measurements. TEM images showed mesopores, and the specific area of mIOC was compared with that of IOC using BET analysis. A half-cell test was performed to compare a-IOC with IOC and mIOC with IOC. In the case of the a-IOC structure, the cell test revealed no improvement in the reversible specific capacity or the cycle performance. The mIOC cell showed a reversible specific capacity of 432 mAh/g, and the capacity was maintained at 88%-approximately 380 mAh/g-over 20 cycles.

  5. Diagenesis of 1900-year-old siliceous sinter (opal-A to quartz) at Opal Mound, Roosevelt Hot Springs, Utah, U.S.A.

    Science.gov (United States)

    Lynne, Bridget Y.; Campbell, Kathleen A.; Moore, J. N.; Browne, P. R. L.

    2005-08-01

    White, vitreous, siliceous sinter dated by 14C at ˜1900 years BP is located along the crest of the Opal Mound deposit at Roosevelt Hot Springs, Utah, U.S.A. Deposition at vents resulted from the Opal Mound fault opening conduits to the surface, allowing thermal fluids to discharge. Fault movement subsequently fractured the sinter and initiated a second period of fluid discharge. Colorful silica was deposited in this later period and formed the distal slope sinter, dated at ˜1600 years BP. The sinter preserves both end-members in the mineralogical maturation of silica, from initial opal-A to mature quartz, and also records incremental intermediate steps, as revealed by X-ray powder diffractrometry and by scanning electron, optical and Raman laser microscopy. Textural and mineralogical changes from one silica phase to another transpired gradually and gradationally. During diagenesis, incremental morphological changes alternated three times through nano- to micro-particle size transitions. The three corresponding mineralogical steps comprise: (1) opal-A to opal-CT, (2) opal-CT to opal-C, and (3) opal-C to quartz. Mineralogical changes preceded all morphological changes. Each step was initiated when silica nanostructures reached a critical diameter of 200 nm. The initial starting point of fresh (modern), polymeric, siliceous sinter deposition worldwide is nano-spherical particles of colloidal opal-A. Opaline sinter at Opal Mound is slightly more mature, reflecting the beginning of the aging process, and comprises botryoidal clusters of silica microspheres (quartz formation, the opal-C nano-rods recrystallize into groups of blocky nanostructures, each up to 200 × 300 nm. Quartz crystals grow at the expense of and pseudomorph opal-C, shown by remnant bands of blocky nanostructures at the base of the quartz crystals. Two generations of quartz crystals occur at Opal Mound: (1) diagenetic, which developed as opal-C nanostructures recrystallize to quartz; and (2

  6. Responsive inverse opal hydrogels for the sensing of macromolecules.

    Science.gov (United States)

    Couturier, Jean-Philippe; Sütterlin, Martin; Laschewsky, André; Hettrich, Cornelia; Wischerhoff, Erik

    2015-05-26

    Dual responsive inverse opal hydrogels were designed as autonomous sensor systems for (bio)macromolecules, exploiting the analyte-induced modulation of the opal's structural color. The systems that are based on oligo(ethylene glycol) macromonomers additionally incorporate comonomers with various recognition units. They combine a coil-to-globule collapse transition of the LCST type with sensitivity of the transition temperature toward molecular recognition processes. This enables the specific detection of macromolecular analytes, such as glycopolymers and proteins, by simple optical methods. While the inverse opal structure assists the effective diffusion even of large analytes into the photonic crystal, the stimulus responsiveness gives rise to strong shifts of the optical Bragg peak of more than 100 nm upon analyte binding at a given temperature. The systems' design provides a versatile platform for the development of easy-to-use, fast, and low-cost sensors for pathogens.

  7. Luminescence response of synthetic opal under femtosecond laser pumping

    Energy Technology Data Exchange (ETDEWEB)

    Vasnetsov, M.V., E-mail: vasnet@hotmail.com [Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03680 (Ukraine); Bazhenov, V.Yu.; Dmitruk, I.N. [Institute of Physics, National Academy of Sciences of Ukraine, Prospect Nauki 46, Kiev 03680 (Ukraine); Kudryavtseva, A.D.; Tcherniega, N.V. [P. N. Lebedev Physical Institute of Russian Academy of Sciences, Leninskii Prospect 53, Moscow 119991 (Russian Federation)

    2015-10-15

    Synthetic opal is an artificial photonic metamaterial composed from spherical globules of amorphous silica (SiO{sub 2}) about 300 nm in diameter. We report, for the first time to our knowledge, the origin of a narrow luminescence spectral peak (4 nm HWHM) and optical second and third harmonic generation in synthetic opal samples under femtosecond laser excitation (800 nm) at liquid-nitrogen temperature. Stimulated-emission effects are discussed related to the possibility of nanocavity lasing at the condition of the first Mie resonance in a dielectric sphere. - Highlights: • Second harmonic generation in a synthetic opal (amorphous material composed from spherical SiO{sub 2} globules) was observed. • Narrow luminescence peak which we assign to a Mie resonance in a globule was detected at liquid-nitrogen temperature.

  8. Thermochromic effect in synthetic opal/polyaniline composite structures

    Science.gov (United States)

    Rahman, F.; Khokhar, A. Z.

    2009-02-01

    The design and construction of a novel storage/indicator bilayer system is described where ammonia gas stored in a porous material can be used to dope a colour-changing polyaniline film. Both reversible and irreversible colour change effects are possible. A thin synthetic opal film is coupled to a polyaniline film in a parallel plate glass cell with ammonia gas adsorbed on the silica balls that form the opal structure. When heated and cooled, ammonia reversibly exchanges between the opal and polyaniline films causing a very distinct change in the colour of the polyaniline film. This thermochromic effect is also electrically detectable because of the large concomitant change in the resistivity of the polyaniline film that accompanies its colour change.

  9. Stimulated Brillouin scattering enhancement in silicon inverse opal waveguides

    CERN Document Server

    Smith, M J A; de Sterke, C Martijn; Lapine, M; Kuhlmey, B T; Poulton, C G

    2016-01-01

    Silicon is an ideal material for on-chip applications, however its poor acoustic properties limit its performance for important optoacoustic applications, particularly for Stimulated Brillouin Scattering (SBS). We theoretically show that silicon inverse opals exhibit a strongly improved acoustic performance that enhances the bulk SBS gain coefficient by more than two orders of magnitude. We also design a waveguide that incorporates silicon inverse opals and which has SBS gain values that are comparable with chalcogenide glass waveguides. This research opens new directions for opto-acoustic applications in on-chip material systems.

  10. Optical monitoring the degradation of PLGA inverse opal film

    Institute of Scientific and Technical Information of China (English)

    Li-Guo Sun; Zhuo-Ying Xie; Yuan-Jin Zhao; Hong-Mei Wei; Zhong-Ze Gu

    2013-01-01

    Implantable materials have broad applications in tissue engineering and in vivo sensors.It is essential to know the detailed information of the implantable materials during their degradation.In this paper,we developed a method to monitor the degradation process of a well-used biomaterial,poly(lactide-coglycolide) (PLGA) by taking advantage of inverse opal structure.We found that mass loss,molecular weight and glass transition temperature of PLGA during the degradation process in Hank's artificial body fluid can be in situ monitored by measuring the optical properties of PLGA inverse opal.

  11. OPAL - extension for use with ventilation and pump systems; OPAL-Erweiterung mit Luefter- und Pumpensystemen

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.

    2003-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses how an existing software tool called OPAL that supports the energy-efficient dimensioning of electrical drive systems was extended to cover pump and fan applications. According to the authors, the new version 3 allows the energy efficiency of such systems as well as the economic feasibility of many types of improvement projects to be evaluated in a fast and accurate manner. Software is described that has been designed and optimised using real world examples that can be often found in the water supply and facility management areas. These include heating-system pumps as well as ventilation and pressure-boosting applications. The practicability and benefits offered by the tool are demonstrated using several examples.

  12. OPAL - extension for use with ventilation and pump systems; OPAL-Erweiterung mit Luefter- und Pumpensystemen

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.

    2003-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) discusses how an existing software tool called OPAL that supports the energy-efficient dimensioning of electrical drive systems was extended to cover pump and fan applications. According to the authors, the new version 3 allows the energy efficiency of such systems as well as the economic feasibility of many types of improvement projects to be evaluated in a fast and accurate manner. Software is described that has been designed and optimised using real world examples that can be often found in the water supply and facility management areas. These include heating-system pumps as well as ventilation and pressure-boosting applications. The practicability and benefits offered by the tool are demonstrated using several examples.

  13. Picture Books about Blacks: An Interview with Opal Moore.

    Science.gov (United States)

    MacCann, Donnarae; Richard, Olga

    1991-01-01

    Presents an interview with Opal Moore, who discusses Black imagery in picture books published in the last four years and the institutions that circulate that imagery. Topics discussed include the issue of race pride; interracial themes; appropriate illustrations; African versus African-American books; and the roles of publishers, books reviewers,…

  14. Oxygen Isotopes and Origin of Opal in an Antarctic Ureilite

    Science.gov (United States)

    Downes, H.; Beard, A. D.; Franchi, I. A.; Greenwood, R. C.

    2016-08-01

    Fragments of opal (SiO2.nH2O) in several internal chips of a single Antarctic polymict ureilite meteorite Elephant Moraine (EET) 83309 have been studied by NanoSIMS to determine their oxygen isotope compositions and hence constrain their origin.

  15. Wood opals from Yakuplu, Turkey: their properties and genesis

    NARCIS (Netherlands)

    Buurman, P.

    1975-01-01

    Fossil driftwood from Sarmatian (Late Miocene) gravel deposits near Yakuplu, Turkey, ranges between lignitic and opaline. Opalization occurred in various stages of decay. The stage of decay of the wood and the eventual admixture of detritic clay influenced the crystallinity and the dehydration chara

  16. Artificial black opal fabricated from nanoporous carbon spheres.

    Science.gov (United States)

    Yamada, Yuri; Ishii, Masahiko; Nakamura, Tadashi; Yano, Kazuhisa

    2010-06-15

    A nanocasting method via chemical vapor deposition of acetonitrile was successfully employed to fabricate porous carbon colloidal crystal using colloidal crystal from monodispersed mesoporous silica spheres (MMSS) as a sacrificial scaffold. The mesostructure as well as periodic arrays within (111) plane of MMSS were replicated for the carbon colloidal crystal (black opal) with the length scale in the centimeter range. Brilliant iridescent colors were clearly observed for the first time on the black carbon colloidal crystal fabricated from porous carbon spheres, and they changed dramatically in accordance with the observation angle, like natural black opals. Reflection spectra measurements based on 2D surface diffraction and Bragg diffraction in the mirror mode were conducted for the fabricated carbon periodic arrays. The periodicity in the (111) plane as well as in the direction perpendicular to the (111) plane of the colloidal crystal was evaluated by comparing the results obtained from these two measurements. It was found that the periodicity in the direction perpendicular to the (111) surface is not high for the obtained black carbon opal. On the other hand, the relationship between the incident angles and the peak wavelengths of the reflection spectra, collected in the condition where the incident light and the reflected light pass through in the same direction, is governed by an approximation based on 2D surface diffraction. The results imply that the origin of the iridescent colors on the fabricated black carbon opal is derived from the periodicity not in the direction perpendicular to the (111) plane but within the (111) plane.

  17. Submarine barite-opal rocks of hydrothermal origin.

    Science.gov (United States)

    Bertine, K K; Keene, J B

    1975-04-11

    Unusual submarine rocks consisting of barite, opal, and volcanic detritus were recovered from the Lau Basin northeast of Australia. It is proposed that these rocks were formed when hydrothermal solutions emanating from a fracture zone offsetting the active spreading center in the Lau Basin came into contact with cooler ocean waters.

  18. Effects of heating on fire opal and diaspore from Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Hatipoglu, M. [Dokuz Eyluel University, IMYO, Izmir Multidisciplinary Vocational School, Gemmology and Jewelry Program, 35160 Buca, Izmir (Turkey); Can, N., E-mail: cannurdogan@yahoo.co [Celal Bayar University, Faculty of the Arts and Sciences, Department of Physics, 45100 Muradiye, Manisa (Turkey); Karali, T. [Ege University, Applied School of Nuclear Sciences, 35100 Bornova, Izmir (Turkey)

    2010-04-01

    Fire opal (SiO{sub 2}.nH{sub 2}O) and diaspore [Al(OH)O] are two different precious and rare mineral species with high water content. While these species are being cut and polished to make gems, defect-induced weaknesses such as fragility, splintering, and cracking become apparent since the temperature of the mineral species may be increased to high temperatures during the process. These deformations may be broadly related to water loss (molecular (H{sub 2}O) and hydroxyl (OH) group) and transformation of the base building components and/or inclusion minerals. In this study, thermal properties and thermal stability as dehydratial behaviors of both gem quality fire opal (SiO{sub 2}.nH{sub 2}O) from the Saphane region (Kuetahya, Turkey) and gem quality diaspore (AlOHO) from the Milas region (Mugla, Turkey), including some associated mineral inclusions, were studied by means of X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier transform-Infrared absorption (FTIR) spectroscopy and thermal analysis (DTA/TGA). During heating to 1400 deg. C, DTA/TGA patterns indicated that the weight losses of the fire opal and diaspore were due to the water loss only, and that these losses occur in the temperature ranges between about 342 and 722 deg. C in fire opal, and between about 592 and 718 deg. C in diaspore. In addition, after making some corrections concerning the mass gain observed, being due to the drift with buoyancy effect of the atmosphere, in their TGA curves, the fire opal shows a mass loss of 7.942%, and one distinctive sharp endotherm at 1089.99 deg. C and seven weaker endotherms, whereas the diaspore shows a mass loss of about 13.826%, and one distinctive sharpest endotherm at 650.47 deg. C and four weaker endotherms.

  19. Opal instability: a relationship between water and microstructure?

    Science.gov (United States)

    Chauviré, Boris; Thomas, Paul; Rondeau, Benjamin; Fritsch, Emmanuel

    2017-04-01

    Unlike other gem minerals, opals can suffer a change in their quality with time, resulting in a lack of confidence and hence marketability of this gemstone. The instability has been described and categorized into 2 main types (Aguilar et al., 2004; Aguilar-Reyes et al., 2005; Rondeau et al., 2011): cracking (development of a network of micro-fractures) and whitening (decrease of transparency). Available literature about opal instability, however, is restricted to its description. Although the process involved in the destabilization remains poorly understood, it has been proved, in at least one instance, to be associated with the release of water and a change of its speciation (Pearson, 1985; Paris et al, 2007). We propose 3 models to explain the cracking and/or whitening: (i) drying shrinkage of microstructural units, (ii) differential partial pressure between water enclosed in the opal and atmosphere and (iii) release of water yielding empty pores resulting in a strong light-scattering and hence opacity. In order to ascertain the model, a comprehensive set of opals from various origin and structure have been selected for investigation base on previous heating experiments which identified samples with a high susceptibility to crack or whiten. These samples will be investigated to identify the origins of the destabilization phenomena using infrared spectroscopy (FTIR), thermal analysis (gravimetric (TG) and calorimetric (DSC)) and gas adsorption measurements. FTIR will allow the main species of water present in opals (molecular water and hydroxyl groups) and their proportion to be determined while TG will be used to accurately determine the total water content. Gas adsorption and thermoporosity (DSC) will be used to characterize the porosity (surface area, pore size and crystallizable water content). The characterization of water and microstructure for each opal may provide the potential link between the mobility of water in the microstructure and the observed

  20. OPAL extension for permanent-magnet motors; OPAL-Erweiterung fuer Permanentmagnet-Motoren - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.

    2008-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at an extension to the OPAL software that is concerned with the energy-efficient design of pump and fan systems that use induction motors. This software has been extended by a module for permanent magnet motors which directly addresses the question of how much energy and cost can be saved through the use of this type of motors compared to ASM standard motors. However, it is noted that certain parameters of permanent magnet motors necessary to make use of this new design feature must be available, which is currently not the case. In order to make this design application available to a wider group of users, a web-based user interface has been developed. New Web-2.0 features that have been included to provide improved usability are discussed. In addition, it is noted that the software has now been adapted to support German, English and French versions. Also, the EuroDEEM database has been integrated, thus giving access to the performance data of more than 10,000 motors.

  1. Fluorescence resonance energy transfer between conjugated molecules infiltrated in three-dimensional opal photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Lu; Sui, Ning; Wang, Ying-Hui, E-mail: yinghui_wang@jlu.edu.cn; Qian, Cheng; Ma, Yu-Guang; Zhang, Han-Zhuang, E-mail: zhanghz@jlu.edu.cn

    2015-02-15

    Fluorescence resonance energy transfer (FRET) from Coumarin 6 (C-6) to Sulforhodamine B (S-B) infiltrated into opal PMMA (poly-methyl-methacrylate) photonic crystals (PCs) has been studied in detail. The intrinsic mesh micro-porous structure of opal PCs could increase the luminescent efficiency through inhibiting the intermolecular interaction. Meanwhile, its structure of periodically varying refractive indices could also modify the FRET through affecting the luminescence characteristics of energy donor or energy acceptor. The results demonstrate that the FRET efficiency between conjugated dyes was easily modified by opal PCs. - Highlights: • We investigate the fluorescence resonance energy transfer between two kinds of dyes. • These two kinds of dyes are infiltrated in PMMA opal photonic crystals. • The structure of opal PCs could improve the luminescent characteristics. • The structure of opal PCs could improve the energy transfer characteristics.

  2. Electrochemical properties of opal-V{sub 6}O{sub 13} composites

    Energy Technology Data Exchange (ETDEWEB)

    Vernardou, D., E-mail: dimitra@iesl.forth.gr [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Apostolopoulou, M. [Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Louloudakis, D. [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Department of Physics, University of Crete, 710 03 Heraklion, Crete (Greece); Spanakis, E. [Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete (Greece); Katsarakis, N. [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas, P.O. Box 1527, Vassilika Vouton, 711 10 Heraklion, Crete (Greece); Koudoumas, E. [Center of Materials Technology and Photonics, School of Applied Technology, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); Electrical Engineering Department, Technological Educational Institute of Crete, 710 04 Heraklion, Crete (Greece); McGrath, J.; Pemble, M.E. [Tyndall National Institute, University College Cork, Lee Maltings, Prospect Row, Cork (Ireland)

    2014-02-15

    Highlights: • Opal-V{sub 6}O{sub 13} composites grown at 95 °C for 50 h. • The deposition period affects the void filling of the opals. • The electrochemical performance is correlated with the oxide’s characteristics. -- Abstract: Vanadium oxides were hydrothermally grown on opal glass substrates at 95 °C. The deposition period was observed to affect the structure of the oxides and the voids filling of the opal surfaces. V{sub 6}O{sub 13} grown on opal for 50 h presented satisfactory electrochemical performance and electrochromic response with a contrast ratio of 2. The specific capacitance of this composite reached a value of 192 F g{sup −1}, which was stable up to 500 continuous charge intercalation/deintercalation scans. The importance of achieving crystalline V{sub 6}O{sub 13} and high opal surface coverage towards the enhancement of the electrochemical properties is presented.

  3. Cell orientation gradients on an inverse opal substrate.

    Science.gov (United States)

    Lu, Jie; Zou, Xin; Zhao, Ze; Mu, Zhongde; Zhao, Yuanjin; Gu, Zhongze

    2015-05-20

    The generation of cell gradients is critical for understanding many biological systems and realizing the unique functionality of many implanted biomaterials. However, most previous work can only control the gradient of cell density and this has no effect on the gradient of cell orientation, which has an important role in regulating the functions of many connecting tissues. Here, we report on a simple stretched inverse opal substrate for establishing desired cell orientation gradients. It was demonstrated that tendon fibroblasts on the stretched inverse opal gradient showed a corresponding alignment along with the elongation gradient of the substrate. This "random-to-aligned" cell gradient reproduces the insertion part of many connecting tissues, and thus, will have important applications in tissue engineering.

  4. OPAL Forward Calorimeter (half cylinder with lead scintillator)

    CERN Multimedia

    1 half cylinder piece is available for loan. The OPAL forward Detector Calorimeter was made in 4 half cylindrical pieces. Two full cylinders were placed round the LEP beam pipe about 3m downstream of the interaction point. The detector was used primarily to measure the luminosity of LEP (rate of interactions) and also to trigger on 2-photon events. In addition it formed an essential part of the detector coverage which OPAL needed to carry out searches for new particles such as the Higgs boson. The detector is made of scintillators sandwiched between lead sheets. The light from the scintillators passes via bars of wavelength shifter and light guides on its way to be measured by photomultipliers. There is a layer of gas filled tube chambers within the calorimeter. These provide a measure of the position of the particles interacting in the calorimeter.

  5. Modified optical properties in a samarium doped titania inverse opal.

    Science.gov (United States)

    Wang, Wei; Song, Hongwei; Liu, Qiong; Bai, Xue; Wang, Yu; Dong, Biao

    2010-05-01

    The TiO(2):Sm(3+) inverse opal has been prepared by a template-assisted method, and its modification on photoluminescent (PL) properties of Sm(3+) is studied. Transmittance spectra show a dip within the photonic bandgap, whose location shifts a little to red and then to blue with an increasing detection angle between the incident light and the surface normal; such an irregular shift is attributed to uneven shrinkage of lattices. Steady-state PL spectra indicate a spatial redistribution of emission lines. Decay kinetics demonstrate that the spontaneous emission rates of Sm(3+) ions in the inverse opal decrease to varied extent depending on the emission wavelength and detection angle. All the facts are examined to be consistent with the photonic bandgap effect.

  6. Opal-like photonic crystal with diamond lattice

    CERN Document Server

    Garcia Santamaria, F; López, C; Meseguer, F; Miyazaki, H T; Sánchez-Dehesa, J

    2002-01-01

    In this contribution, a method to fabricate a diamond structure with a complete PBG in the near infrared is proposed. The procedure starts by building an opal composed of two types of microspheres (organic and inorganic) in a body-centered-cubic symmetry by means of a micro- robotic technique. Then, the organic particles may be selectively removed to obtain a diamond structure of inorganic particles. Once this structure is assembled its filling fraction may be controlled by sintering. Subsequently this template can be infiltrated with an adequate high refractive index material. In this way, the method can be extended to make diamond inverse opals of, for instance, silicon with gap to mid gap ratios as large as 13% for moderate filling fractions. An overview of micromanipulation as well as previous experimental results will be offered to show the feasibility of this method. (24 refs).

  7. OPAL Central Detector (Including vertex, jet and Z chambers)

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the different parts of the tracking system. (This piece includes the vertex, jet and Z chambers) In the picture above, the central detector is the piece being removed to the right.

  8. Scaling exponents for fracture surfaces in opal glass

    Energy Technology Data Exchange (ETDEWEB)

    Chavez-Guerrero, L., E-mail: guerreroleo@hotmail.com [Facultad de Ingenieria Mecanica y Electrica. Cd. Universitaria s/n, C.P. 66450, Universidad Autonoma de Nuevo Leon, Nuevo Leon (Mexico); Center of Innovation, Research and Development on Engineering and Technology, Universidad Autonoma de Nuevo Leon Monterrey, C.P. 66600, Apodaca, Nuevo Leon (Mexico); Garza, F.J., E-mail: fjgarza@gama.fime.uanl.mx [Facultad de Ciencias Quimicas, Cd. Universitaria s/n, C.P. 66450, Universidad Autonoma de Nuevo Leon, Nuevo Leon (Mexico); Hinojosa, M., E-mail: hinojosa@gama.fime.uanl.mx [Facultad de Ingenieria Mecanica y Electrica. Cd. Universitaria s/n, C.P. 66450, Universidad Autonoma de Nuevo Leon, Nuevo Leon (Mexico); Center of Innovation, Research and Development on Engineering and Technology, Universidad Autonoma de Nuevo Leon Monterrey, C.P. 66600, Apodaca, Nuevo Leon (Mexico)

    2010-09-25

    We have investigated the scaling properties of fracture surfaces in opal glass. Specimens with two different opacifying particle sizes (1 {mu}m and 0.4 {mu}m) were broken by three-point bending test and the resulting fracture surfaces were analyzed using Atomic Force Microscopy. The analysis of the self-affine behavior was performed using the Variable Bandwidth and Height-Height Correlation Methods, and both the roughness exponent, {zeta}, and the correlation length, {xi}, were determined. It was found that the roughness exponent obtained in both samples is {zeta} {approx} 0.8; whereas the correlation length in both fractures is of the order of the particle size, demonstrating the dependence of this self-affine parameter on the microstructure of opal glass.

  9. Preparation of TiO2 Inverse Opal via a Modified Filling Process

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qian; DONG Peng; YI Gui-Yun; LIU Li-Xia; CHENG Bing-Ying

    2005-01-01

    @@ By applying polystyrene opals made by a vertical deposition method as the templates, a modified filling method and a well-controlled calcination process, we have successfully obtained a large-area ordered TiO2 inverse opal with a higher volume fraction (14.5%) and a visible photonic bandgap. The influences of the filling process and calcination conditions on the fabrication of the TiO2 inverse opal are investigated.

  10. Multifunctional inverse opal particles for drug delivery and monitoring.

    Science.gov (United States)

    Zhang, Bin; Cheng, Yao; Wang, Huan; Ye, Baofen; Shang, Luoran; Zhao, Yuanjin; Gu, Zhongze

    2015-06-28

    Particle-based delivery systems have a demonstrated value for drug discovery and development. Here, we report a new type of particle-based delivery system that has controllable release and is self-monitoring. The particles were composed of poly(N-isopropylacrylamide) (pNIPAM) hydrogel with an inverse opal structure. The presence of macropores in the particles provides channels for active drug loading and release from the materials.

  11. Compact drift-chambers for the OPAL forward detectors

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, B.E.; Attree, D.J.; Charalambous, A.; Cranfield, R.; Cresswell, M.; Crone, G.; Dallavalle, G.M.; Dryburgh, M.; Kennedy, B.W.; Hayes, D.; Marradi, L.; Miller, D.J.; Sherwood, P.; Spreadbury, E.; Wood, N.C.; Young, K.K. (University Coll., London (UK). Dept. of Physics and Astronomy)

    1989-11-10

    Two planes of four chambers are mounted in front of the forward calorimeter at each end of OPAL. Beam tests at CERN show good linearity (within 0.5 mm over 130 mm maximum drift) and good resolution in the drift direction (average 300 {mu}m over the whole range of drift distances). The resolution along the wire is {plus minus}1 mm. (orig.).

  12. Symmetry characterization of eigenstates in opal-based photonic crystals

    OpenAIRE

    Lopez-Tejeira, F.; Ochiai, T; Sakoda, K; Sanchez-Dehesa, J.

    2001-01-01

    The complete symmetry characterization of eigenstates in bare opal systems is obtained by means of group theory. This symmetry assignment has allowed us to identify several bands that cannot couple with an incident external plane wave. Our prediction is supported by layer-KKR calculations, which are also performed: the coupling coefficients between bulk modes and externally excited field tend to zero when symmetry properties mismatch.

  13. OPAL: Decay of Z0 to two jets

    CERN Multimedia

    1989-01-01

    This track is an example of real data collected from the OPAL detector on the Large Electron-Positron (LEP) collider at CERN, which ran between 1989 and 2000. Here a Z0 particle is produced in the collision between an electron and positron that then decays into a quark-antiquark pair. The quark pair is seen as a pair of hadron jets in the detector.

  14. Implementation of New OPAL Tables in Eggleton's Stellar Evolution Code

    Institute of Scientific and Technical Information of China (English)

    Xue-Fei Chen; Christopher A. Tout

    2007-01-01

    Based on previous works of OPAL, we construct a series of opacity tables for various metallicities Z = 0, 0.000 01, 0.000 03, 0.000 1, 0.000 3, 0.001, 0.004, 0.01, 0.02,0.03, 0.04, 0.05, 0.06, 0.08 and 0.1. These tables can be easily used in Eggleton's stellar evolution code in place of the old tables without changing the code. The OPAL tables are used for log10 (T/K) > 3.95 and Alexander's for log10 (T/K) < 3.95. At log10 (T/K) - 3.95, the two groups' data fit well for all hydrogen mass fractions. Conductive opacities are included by reciprocal addition according to the formulae of Yakovlev and Urpin. A comparison of 1 and 5 M⊙ models constructed with the older OPAL tables of Iglesias and Rogers shows that the new opacities have most effect in the late stages of evolution, the extension of the blue loop during helium burning for intermediate-mass and massive stars.

  15. Plio-Pleistocene Biogenic Opal Deposition in the Southern Ocean

    Science.gov (United States)

    Kuhn, G.; Gersonde, R.

    2002-12-01

    About 2/3 of the annual supply of silicic acid to the World Ocean is buried in the Southern Ocean as biogenic silica (BSi), formed by diatoms and radiolaria in surface waters and exported to the seafloor. Main BSi accumulation occurs in an area between the sea ice edge and the Polar Front Zone and seems to be steered by a complex interaction of biological and physical parameters governing the modern Southern Ocean ecosystem. Sediment cores recovered during Ocean Drilling Program Leg 177 and expeditions with RV POLARSTERN reveal the history of the opal deposition in the Atlantic and Pacific sector of the Southern Ocean during the Pliocene and the Pleistocene. This period is characterized by distinct changes and variability in global climate and ocean circulation that can be related to the spatial-temporal distribution of BSi deposition on long and short time scales. Changes in ocean circulation, water mass structure, sea ice and climatic variability that impact the distribution of silicic acid and the development of coarsly silicified diatoms (e.g. Actinocyclus ingens, Thalassiosira antarctica, Fragilariopsis kerguelensis), presenting the major carriers of biogenic opal, control past BSi deposition in the Southern Ocean. Major deposition in the area of the modern Southern Ocean opal belt starts at the Plio/Pleistocene transition. Such strong export of BSi and related organic carbon might have reinforced the trend of global cooling observed since the Mid-Pliocene climate optimum.

  16. Investigation of the Thermal Conductance of Selected Opal Structures

    Science.gov (United States)

    Lamberton, , Jr.; Tritt, Terry M.; Zakhidov, A.; Baughmann, R.; Khayrullin, I.

    1999-11-01

    In relation to thermoelectrics, recently some attention has come to opal structures.^1 The structure of the SiO2 opals is hoped to be useful in lowering thermal conductivity when this structure is infiltrated with traditional thermoelectric materials, such as Bi or Bi_2Te_3. Preliminary measurements show that, by infiltration, it may be possible to increase the thermoelectric figure of merit by improving the ratio of electrical conductivity to thermal conductivity.^2 We have built a new steady state thermal conductivity apparatus for measuring thermal conductivity of samples between 10K and 350K. With this new system the thermal properties of the opal systems and the effects of infiltration will be investigated. Data from the thermal conductivity and heat capacity measurements will be presented and discussed, along with a comparison of thermal conductivity obtained with the laser flash method. 1.) A. Zakhidov et al., Science , 282, 897 (1998) 2.) R. Baughman, A. Zakhidov, et.al, Proc. of ICT '98, IEEE Press, p 288 (1998)

  17. Optics of an opal modeled with a stratified effective index and the effect of the interface

    CERN Document Server

    Maurin, Isabelle; Laliotis, Athanasios; Bloch, Daniel

    2015-01-01

    Reflection and transmission for an artificial opal are described through a model of stratified medium based upon a one-dimensional variation of an effective index. The model is notably applicable to a Langmuir-Blodgett type disordered opal. Light scattering is accounted for by a phenomenological absorption. The interface region between the opal and the substrate -or the vacuum- induces a periodicity break in the photonic crystal arrangement, which exhibits a prominent influence on the reflection, notably away from the Bragg reflection peak. Experimental results are compared to our model. The model is extendable to inverse opals, stacked cylinders, or irradiation by evanescent waves

  18. Synthesis of Polypyrrole Inverse Opal in [bmim]PF6- Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2013-01-01

    Full Text Available Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered polypyrrole (PPy inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF6. PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF6- anions kept dedoping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF6- anions also kept dedoping from the PPy inverse opals, the PO43- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours.

  19. Direct access to macroporous chromium nitride and chromium titanium nitride with inverse opal structure.

    Science.gov (United States)

    Zhao, Weitian; DiSalvo, Francis J

    2015-03-21

    We report a facile synthesis of single-phase, nanocrystalline macroporous chromium nitride and chromium titanium nitride with an inverse opal morphology. The material is characterized using XRD, SEM, HR-TEM/STEM, TGA and XPS. Interconversion of macroporous CrN to Cr2O3 and back to CrN while retaining the inverse opal morphology is also demonstrated.

  20. Small angle X ray diffraction investigation of twinned opal_like structures

    NARCIS (Netherlands)

    Samusev, A.K.; Sinev, I.S.; Samusev, K.B.; Rybin, M.V.; Mistonov, A.A.; Grigoryeva, N.A.; Grigoriev, S.V.; Petukhov, A.V.; Byelov, D.; Trofimova, E.Y.; Kurdyukov, D.A.; Golubev, V.G.; Limonov, M.F.

    2012-01-01

    Small angle X ray diffraction from synthetic opal films has been investigated as a function of the orientation of the sample. All the observed (hkl) diffraction reflections have been interpreted. The reconstruct tion of the reciprocal lattice of the studied opal films has been carried out. The diffr

  1. Small angle X ray diffraction investigation of twinned opal_like structures

    NARCIS (Netherlands)

    Samusev, A.K.; Sinev, I.S.; Samusev, K.B.; Rybin, M.V.; Mistonov, A.A.; Grigoryeva, N.A.; Grigoriev, S.V.; Petukhov, A.V.; Byelov, D.; Trofimova, E.Y.; Kurdyukov, D.A.; Golubev, V.G.; Limonov, M.F.

    2012-01-01

    Small angle X ray diffraction from synthetic opal films has been investigated as a function of the orientation of the sample. All the observed (hkl) diffraction reflections have been interpreted. The reconstruct tion of the reciprocal lattice of the studied opal films has been carried out. The diffr

  2. Fabrication of titania inverse opals by multi-cycle dip-infiltration for optical sensing

    Science.gov (United States)

    Chiang, Chun-Chen; Tuyen, Le Dac; Ren, Ching-Rung; Chau, Lai-Kwan; Wu, Cheng Yi; Huang, Ping-Ji; Hsu, Chia Chen

    2016-04-01

    We have demonstrated a low-cost method to fabricate TiO2 inverse opal photonic crystals with high refractive index skeleton. The TiO2 inverse opal films were fabricated from a polystyrene opal template by multi-cycle dip-infiltration-coating method. The properties of the TiO2 inverse opal films were characterized by scanning electron microscopy and Bragg reflection spectroscopy. The reflection spectroscopic measurements of the TiO2 inverse opal films were compared with theories of photonic band calculations and Bragg law. The agreement between experiment and theory indicates that we can precisely predict the refractive index of the infiltrated liquid sample in the TiO2 inverse opal films from the measurement results. The red-shift of the peak wavelength in the Bragg reflection spectra for both alcohol mixtures and aqueous sucrose solutions of increasing refractive index was observed and respective refractive index sensitivities of 296 and 286 nm/RIU (refractive index unit) were achieved. As the fabrication of the TiO2 inverse opal films and reflection spectroscopic measurement are fairly easy, the TiO2 inverse opal films have potential applications in optical sensing.

  3. Fluorescence lifetime of emitters with broad homogeneous linewidths modified in opal photonic crystals

    DEFF Research Database (Denmark)

    Nikolaev, Ivan S.; Lodahl, Peter; Vos, Willem L.

    2008-01-01

    We have investigated the dynamics of spontaneous emission from dye molecules embedded in opal photonic crystals. Fluorescence lifetimes of Rhodamine 6G (R6G) dye were measured as a function of both optical frequency and crystal lattice parameter of the polystyrene opals. Due to the broad homogene...

  4. Sulfur cathodes with hydrogen reduced titanium dioxide inverse opal structure.

    Science.gov (United States)

    Liang, Zheng; Zheng, Guangyuan; Li, Weiyang; Seh, Zhi Wei; Yao, Hongbin; Yan, Kai; Kong, Desheng; Cui, Yi

    2014-05-27

    Sulfur is a cathode material for lithium-ion batteries with a high specific capacity of 1675 mAh/g. The rapid capacity fading, however, presents a significant challenge for the practical application of sulfur cathodes. Two major approaches that have been developed to improve the sulfur cathode performance include (a) fabricating nanostructured conductive matrix to physically encapsulate sulfur and (b) engineering chemical modification to enhance binding with polysulfides and, thus, to reduce their dissolution. Here, we report a three-dimensional (3D) electrode structure to achieve both sulfur physical encapsulation and polysulfides binding simultaneously. The electrode is based on hydrogen reduced TiO2 with an inverse opal structure that is highly conductive and robust toward electrochemical cycling. The relatively enclosed 3D structure provides an ideal architecture for sulfur and polysulfides confinement. The openings at the top surface allow sulfur infusion into the inverse opal structure. In addition, chemical tuning of the TiO2 composition through hydrogen reduction was shown to enhance the specific capacity and cyclability of the cathode. With such TiO2 encapsulated sulfur structure, the sulfur cathode could deliver a high specific capacity of ∼1100 mAh/g in the beginning, with a reversible capacity of ∼890 mAh/g after 200 cycles of charge/discharge at a C/5 rate. The Coulombic efficiency was also maintained at around 99.5% during cycling. The results showed that inverse opal structure of hydrogen reduced TiO2 represents an effective strategy in improving lithium sulfur batteries performance.

  5. OPAL Cold Neutron Guide In-Pile Replacement

    Energy Technology Data Exchange (ETDEWEB)

    Rownes, T.; Eltobaji, A.; Bell, M.; Klose, F. [Nuclear Operations, Baitain (Australia)

    2013-07-01

    The 20 MW{sub th} OPAL research reactor has five neutron beam assemblies. These provide cold and thermal neutrons to various neutron guides and associated neutron beam instruments. In 2010 a project was initiated to install a new cold neutron guide, CG2, in one of the assemblies. This installation would allow up to four new neutron beam instruments to be built, significantly expanding the reactor's capabilities. The project concluded in December 2012 with the successful installation of CG2. Each neutron beam assembly has an in-pile plug, a primary shutter and a front cover. Together these constitute the neutron guide's in-pile components, with a total mass of over 12 tonnes. The CG2 installation required the complete replacement of the existing components. This replacement was scheduled to coincide with OPAL's first major shutdown. With a budget of $2.3 million and an expected dose of 50 man.mSv, the CG2 installation was a large and complex task. Work during the shutdown involved over 40 ANSTO personnel and radiation fields approached 1 Sv/h in some areas. Despite this, the installation team received a collective dose of only 10 man.mSv, and the project was completed to budget and within schedule. This paper will outline the details of the project, focusing on lessons learned and recommended practices. Each OPAL in-pile plug has a design life of 10 years at full power operation, and similar replacements will be performed regularly as the reactor ages. It is hoped that this information will be useful for other research reactors planning large capital engineering projects.

  6. Photonic crystal heterostructures from self-assembled opals

    Science.gov (United States)

    Khokhar, Ali Z.; Rahman, Faiz; Johnson, Nigel P.

    2011-02-01

    This paper describes the fabrication of opal-based photonic crystal heterostructures. These heterostructures were created by using multilayer deposition of silica and polystyrene spheres. The fabricated structures involved both different lattice constants and different dielectric constants. Single and double heterostructures working in the visible region were fabricated by using techniques described here. The optical properties of these heterostructures were investigated experimentally and showed the superposition of the properties of each individual crystal region as well as optical signatures due to inter-layer defects.

  7. Filtering of elastic waves by opal-based hypersonic crystal.

    Science.gov (United States)

    Salasyuk, Alexey S; Scherbakov, Alexey V; Yakovlev, Dmitri R; Akimov, Andrey V; Kaplyanskii, Alexander A; Kaplan, Saveliy F; Grudinkin, Sergey A; Nashchekin, Alexey V; Pevtsov, Alexander B; Golubev, Valery G; Berstermann, Thorsten; Brüggemann, Christian; Bombeck, Michael; Bayer, Manfred

    2010-04-14

    We report experiments in which high quality silica opal films are used as three-dimensional hypersonic crystals in the 10 GHz range. Controlled sintering of these structures leads to well-defined elastic bonding between the submicrometer-sized silica spheres, due to which a band structure for elastic waves is formed. The sonic crystal properties are studied by injection of a broadband elastic wave packet with a femtosecond laser. Depending on the elastic bonding strength, the band structure separates long-living surface acoustic waves with frequencies in the complete band gap from bulk waves with band frequencies that propagate into the crystal leading to a fast decay.

  8. The OPAL Detector (an~Omni~Purpose~Apparatus~for~Lep)

    CERN Multimedia

    Schaile, D A; Watson, N; Craciun, M; Hanson, G; Mcmahon, T J; Stokes, W; Wilson, G W; Carter, J; Plane, D; Scharff-hansen, P; Sahr, O M; Rembser, C; Saeki, T; Nisius, R; Campana, S; Kormos, L L; Marchant, T E; Takeda, H; Kupper, M; Hill, J C; Hajdu, C; Hauschild, M; Charlton, D; Kellogg, R; Kluth, S; Asai, S; Nellen, B; Bright-thomas, P; Polok, J; Guenther, P O; Keeler, R; Schwick, C; Stephens, K; Zankel, K; Watkins, P; Chang, C Y; Roney, M; Fischer, H; Dubbert, J

    2002-01-01

    The OPAL Detector (an Omni Purpose Apparatus for Lep) \\\\ \\\\OPAL, a general purpose detector, was designed to study a wide range of unexplored physics at LEP. \\\\ \\\\At LEP1, one of the central issues is the precise determination of the mass, width and couplings to quarks and leptons of the Z$^{0}$ boson. At LEP2 the mass and couplings of the W$^\\pm$ bosons are determined. Accurate measurements of these quantities might reveal the mechanisms by which symmetries are broken. Many topics relating to heavy flavours are studied, including the properties of tau leptons, and the spectroscopy, lifetimes and mixing of hadrons containing b-quarks. \\\\ \\\\There are very active QCD and Two-Photon groups. Among the topics being studied are the determination of the strong coupling constant, $ \\alpha _{S} $, tests of the group structure of QCD, differences between quark- and gluon-induced jets, many aspects of the fragmentation process measurements of many different final states in photon-photon collision, and measurement of str...

  9. Patterning hierarchy in direct and inverse opal crystals.

    Science.gov (United States)

    Mishchenko, Lidiya; Hatton, Benjamin; Kolle, Mathias; Aizenberg, Joanna

    2012-06-25

    Biological strategies for bottom-up synthesis of inorganic crystalline and amorphous materials within topographic templates have recently become an attractive approach for fabricating complex synthetic structures. Inspired by these strategies, herein the synthesis of multi-layered, hierarchical inverse colloidal crystal films formed directly on topographically patterned substrates via evaporative deposition, or "co-assembly", of polymeric spheres with a silicate sol-gel precursor solution and subsequent removal of the colloidal template, is described. The response of this growing composite colloid-silica system to artificially imposed 3D spatial constraints of various geometries is systematically studied, and compared with that of direct colloidal crystal assembly on the same template. Substrates designed with arrays of rectangular, triangular, and hexagonal prisms and cylinders are shown to control crystallographic domain nucleation and orientation of the direct and inverse opals. With this bottom-up topographical approach, it is demonstrated that the system can be manipulated to either form large patterned single crystals, or crystals with a fine-tuned extent of disorder, and to nucleate distinct colloidal domains of a defined size, location, and orientation in a wide range of length-scales. The resulting ordered, quasi-ordered, and disordered colloidal crystal films show distinct optical properties. Therefore, this method provides a means of controlling bottom-up synthesis of complex, hierarchical direct and inverse opal structures designed for altering optical properties and increased functionality. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Progress with OPAL, the new Australian research reactor

    Indian Academy of Sciences (India)

    R A Robinson

    2008-11-01

    Australian science is entering a new `golden age', with the start-up of bright new neutron and photon sources in Sydney and Melbourne, in 2006 and 2007 respectively. The OPAL reactor and the Australian Synchrotron can be considered as the greatest single investment in scientific infrastructure in Australia's history. They will essentially be `sister' facilities, with a common open user ethos, and a vision to play a major role in international science. Fuel was loaded into the reactor in August 2006, and full power was (20 MW) achieved in November 2006. The first call for proposals was made in 2007, and commissioning experiments have taken place well before then. The first three instruments in operation are high-resolution powder diffractometer (for materials discovery), high-intensity powder diffractometer (for kinetics experiments and small samples) and a strain scanner (for mechanical engineering and industrial applications). These are closely followed by four more instruments with broad application in nanoscience, condensed matter physics and other scientific disciplines. Instrument performance will be competitive with the best research-reactor facilities anywhere. To date there is committed funding for nine instruments, with a capacity to install a total of ∼ 18 beamlines. An update will be given on the status of OPAL, its thermal and cold neutron sources, its instruments and the first results.

  11. Quasi-ballistic Electronic Thermal Conduction in Metal Inverse Opals.

    Science.gov (United States)

    Barako, Michael T; Sood, Aditya; Zhang, Chi; Wang, Junjie; Kodama, Takashi; Asheghi, Mehdi; Zheng, Xiaolin; Braun, Paul V; Goodson, Kenneth E

    2016-04-13

    Porous metals are used in interfacial transport applications that leverage the combination of electrical and/or thermal conductivity and the large available surface area. As nanomaterials push toward smaller pore sizes to increase the total surface area and reduce diffusion length scales, electron conduction within the metal scaffold becomes suppressed due to increased surface scattering. Here we observe the transition from diffusive to quasi-ballistic thermal conduction using metal inverse opals (IOs), which are metal films that contain a periodic arrangement of interconnected spherical pores. As the material dimensions are reduced from ∼230 nm to ∼23 nm, the thermal conductivity of copper IOs is reduced by more than 57% due to the increase in surface scattering. In contrast, nickel IOs exhibit diffusive-like conduction and have a constant thermal conductivity over this size regime. The quasi-ballistic nature of electron transport at these length scales is modeled considering the inverse opal geometry, surface scattering, and grain boundaries. Understanding the characteristics of electron conduction at the nanoscale is essential to minimizing the total resistance of porous metals for interfacial transport applications, such as the total electrical resistance of battery electrodes and the total thermal resistance of microscale heat exchangers.

  12. MODIFIED OPAL:A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    Xueren Qian; Xianhui An; Wenbo Liu; Gang Yu; Zhanqian Song

    2004-01-01

    The possibility of modified opal as the stabilizer of hydrogen peroxide bleaching was investigated. The results showed that the modified opal in place of sodium silicate as the stabilizer of hydrogen peroxide bleaching is feasible. At the same dosage, above 3% ISO can be increased for both wheat straw pulp and deinked pulp. The stabilizing ability of the modified opal to hydrogen peroxide bleaching of pulp is improved markedly. It is favorable for bleaching to increase temperature and time within a permissive extent. The suitable process conditions are 10% of pulp consistency, 3% of hydrogen peroxide, 1.5% of sodium hydroxide, 3% of the modified opal, 70℃ and 60 min when the modified opal is used as the stabilizer of hydrogen peroxide bleaching. At these conditions, the brightness gain can reach about 16% ISO for wheat straw pulp. In addition, it is favorable for bleaching to add a little magnesium sulfate when the modified opal is used as the stabilizer of hydrogen peroxide bleaching, the brightness of pulp can increase I%ISO if0.05% of magnesium sulfate is added. The cost analysis indicated that the modified opal is superior to sodium silicate as the stabilizer of hydrogen peroxide bleaching in economical aspect and has further the potential of market development.

  13. Face-Centred-Cubic Artificial Opal Embedded with CdS Quantum Dots

    Institute of Scientific and Technical Information of China (English)

    徐岭; 李明海; 张宇; 马懿; 徐骏; 黄信凡; 陈坤基

    2002-01-01

    Highly monodispersed colloidal silica spheres in sub-micrometre size with distribution standard deviation less than 5% were synthesized by a chemical method. Using the self-crystallization of the silica spheres, we successfully obtained the three-dimensional close-packed face-centred-cubic silica matrices and artificial opals. Then,a colloidal photonic crystal embedded with CdS quantum dots (QDs) was also chemically prepared by using artificial opals as a template. A reflection spectra study reveals that both artificial opals with and without CdS QDs possess (111) directional photonic bandgap features.

  14. Reflection of focused beams from opal photonic crystals.

    Science.gov (United States)

    Varis, Karri; Mattila, Marco; Arpiainen, Sanna; Ahopelto, Jouni; Jonsson, Fredrik; Sotomayor Torres, Clivia; Egen, Marc; Zentel, Rudolf

    2005-04-04

    We present a robust method for computing the reflection of arbitrarily shaped and sized beams from finite thickness photonic crystals. The method is based on dividing the incident beam into plane waves, each of which can be solved individually using Bloch periodic boundary conditions. This procedure allows us to take a full advantage of the crystal symmetry and also leads to a linear scaling of the computation time with respect to the number of plane waves needed to expand the incident beam. The algorithm for computing the reflection of an individual plane wave is also reviewed. Finally, we find an excellent agreement between the computational results and measurement data obtained from opals that are synthesized using polystyrene and poly(methyl methacrylate) microspheres.

  15. Analysis of trace elements in opal using PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Hinrichs, Ruth, E-mail: ruth.hinrichs@ufrgs.br [Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Bertol, A.P.L. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Vasconcellos, M.A.Z. [Programa de Pós-graduação em Física, UFRGS, Porto Alegre, RS (Brazil); Instituto de Física, UFRGS, Porto Alegre, RS (Brazil)

    2015-11-15

    Particle induced X-ray emission (PIXE) analysis is particularly important for the analysis of trace elements of precious samples, being one of the few methods to determine elements with ppm concentration that does not affect sample integrity. A PIXE methodology for trace element analysis in opal was developed. To avoid detector count saturation due to the high number of Si-Kα X-rays generated in the sample, several filters were employed to optimize the reduction of the Si-Kα signal, while maintaining acceptable intensities of the other relevant X-ray lines. Two proton beam energies were tested, to establish the signal to noise ratio in different X-ray energies. Spectra were fitted with the software GUPIX, using a matrix composition determined with electron beam excited energy dispersive X-ray spectrometry. Above the energy of the silicon X-ray, several trace elements were quantified.

  16. Nanoparticle-tuned structural color from polymer opals.

    Science.gov (United States)

    Pursiainen, Otto L; Baumberg, Jeremy J; Winkler, Holger; Viel, Benjamin; Spahn, Peter; Ruhl, Tilmann

    2007-07-23

    The production of high-quality low-defect single-domain flexible polymer opals which possess fundamental photonic bandgaps tuneable across the visible and near-infrared regions is demonstrated in an industrially-scalable process. Incorporating sub-50nm nanoparticles into the interstices of the fcc lattice dramatically changes the perceived color without affecting the lattice quality. Contrary to iridescence based on Bragg diffraction, color generation arises through spectrally-resonant scattering inside the 3D photonic crystal. Viewing angles widen beyond 40 masculine removing the strong dependence of the perceived color on the position of light sources, greatly enhancing the color appearance. This opens up a range of decorative, sensing, security and photonic applications, and suggests an origin for structural colors in Nature.

  17. Rectification of the OPAL Cold Neutron Source Cryogenic System

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Weijian [Australian Nuclear Science and Technology Organisation, Sydney (Australia)

    2013-07-01

    The Cold Neutron Source (CNS) at ANSTO's OPAL Reactor had experienced repeated outages since 2009 due to failures in the cryogenic system. An extensive root cause analysis was initiated in May 2012, led by an ANSTO team that also involved knowledgeable external experts. At the conclusion of the investigation, a set of recommendations was released to address the identified contributing causes. A rectification program was established to implement the solutions. Cryogenic operation of the CNS, providing end users with cold neutrons, successfully returned to service in July 2013. Thanks to the unique stand-by operation mode of the CNS, irradiation activities at the reactor, as well as thermal neutron availability, had not been affected during the year-long investigation/rectification process. Some technical and operational aspects of the investigation, testing and engineering modifications are discussed in this presentation.

  18. Modulating light propagation in ZnO-Cu₂O-inverse opal solar cells for enhanced photocurrents.

    Science.gov (United States)

    Yantara, Natalia; Pham, Thi Thu Trang; Boix, Pablo P; Mathews, Nripan

    2015-09-01

    The advantages of employing an interconnected periodic ZnO morphology, i.e. an inverse opal structure, in electrodeposited ZnO/Cu2O devices are presented. The solar cells are fabricated using low cost solution based methods such as spin coating and electrodeposition. The impact of inverse opal geometry, mainly the diameter and thickness, is scrutinized. By employing 3 layers of an inverse opal structure with a 300 nm pore diameter, higher short circuit photocurrents (∼84% improvement) are observed; however the open circuit voltages decrease with increasing interfacial area. Optical simulation using a finite difference time domain method shows that the inverse opal structure modulates light propagation within the devices such that more photons are absorbed close to the ZnO/Cu2O junction. This increases the collection probability resulting in improved short circuit currents.

  19. Ordered macroporous platinum electrode and enhanced mass transfer in fuel cells using inverse opal structure.

    Science.gov (United States)

    Kim, Ok-Hee; Cho, Yong-Hun; Kang, Soon Hyung; Park, Hee-Young; Kim, Minhyoung; Lim, Ju Wan; Chung, Dong Young; Lee, Myeong Jae; Choe, Heeman; Sung, Yung-Eun

    2013-01-01

    Three-dimensional, ordered macroporous materials such as inverse opal structures are attractive materials for various applications in electrochemical devices because of the benefits derived from their periodic structures: relatively large surface areas, large voidage, low tortuosity and interconnected macropores. However, a direct application of an inverse opal structure in membrane electrode assemblies has been considered impractical because of the limitations in fabrication routes including an unsuitable substrate. Here we report the demonstration of a single cell that maintains an inverse opal structure entirely within a membrane electrode assembly. Compared with the conventional catalyst slurry, an ink-based assembly, this modified assembly has a robust and integrated configuration of catalyst layers; therefore, the loss of catalyst particles can be minimized. Furthermore, the inverse-opal-structure electrode maintains an effective porosity, an enhanced performance, as well as an improved mass transfer and more effective water management, owing to its morphological advantages.

  20. Hierarchical opal grating films prepared by slide coating of colloidal dispersions in binary liquid media.

    Science.gov (United States)

    Lee, Wonmok; Kim, Seulgi; Kim, Seulki; Kim, Jin-Ho; Lee, Hyunjung

    2015-02-15

    There are active researches on well ordered opal films due to their possible applications to various photonic devices. A recently developed slide coating method is capable of rapid fabrication of large area opal films from aqueous colloidal dispersion. In the current study, the slide coating of polystyrene colloidal dispersions in water/i-propanol (IPA) binary media is investigated. Under high IPA content in a dispersing medium, resulting opal film showed a deterioration of long range order, as well as a decreased film thickness due to dilution effect. From the binary liquid, the dried opal films exhibited the unprecedented topological groove patterns with varying periodic distances as a function of alcohol contents in the media. The groove patterns were consisted of the hierarchical structures of the terraced opal layers with periodic thickness variations. The origin of the groove patterns was attributed to a shear-induced periodic instability of colloidal concentration within a thin channel during the coating process which was directly converted to a groove patterns in a resulting opal film due to rapid evaporation of liquid. The groove periods of opal films were in the range of 50-500 μm, and the thickness differences between peak and valley of the groove were significantly large enough to be optically distinguishable, such that the coated films can be utilized as the optical grating film to disperse infra-red light. Utilizing a lowered hydrophilicity of water/IPA dispersant, an opal film could be successfully coated on a flexible Mylar film without significant dewetting problem.

  1. Status of the OPAL microvertex detector and new radiation monitoring and beam dump system

    Science.gov (United States)

    Jong, Sijbrand de

    1998-11-01

    The status of the OPAL Phase III microvertex detector is discussed briefly. This is followed by a more detailed description of the OPAL microvertex detector radiation monitoring and beam dump system. This system measures AC currents induced by radiation on each passing of the beams in silicon diodes mounted close to the microvertex detector front-end electronics. Examples are shown for incidents leading to a beam dump trigger. The integrated radiation dose is also discussed.

  2. A Raman, infrared and XRD analysis of the instability in volcanic opals from Mexico

    Science.gov (United States)

    Ostrooumov, Mikhail

    2007-12-01

    A series of natural volcanic opal samples with the destabilization phenomena from Mexican deposits (states of Queretaro and Jalisco) was investigated by Raman microprobe (RMP), infrared spectrometry and XRD analysis. These techniques show that at low and room temperatures the unaltered transparent opals may be transformed into destabilized white opals, which are a mixture of different polymorphs of tridymite and α-cristobalite with various degrees of crystallinity. We found systematic changes in frequencies of both the Raman and the infrared bands, caused by increasing regularities of bond-lengths and bond-angles Si-O-Si groups under the effect of stability. Micro-Raman spectrometry confirms that in the destabilized opal the principal mineral phases are MC (monoclinic ordered)- and MX (incommensurate monoclinic)-tridymites that are characterized by more structural order in comparison with other structural modification of this phase in unaltered opal (POn pseudo-orthorhombic disordered tridymite). XRD investigations show that in the sequence from unaltered to destabilized opal the position of principal maximum (4.30, 4.10 and 2.50 Å) shifts towards higher d-spacing. This XRD shifting to higher d-spacing can largely be explained by an increasing amount of tridymite stacking and unresolved superposition of cristobalite and tridymite reflections. The destabilization phenomena in volcanic opals is due to the structural ordering/disordering that is characterized mainly by the formation of the different tridymite polymorphs (MC and MX) in the destabilized opal-CT as well as the decreasing content of molecular water in the structure.

  3. Nano-structure of the cristobalite and tridymite stacking sequences in the common purple opal from the Gevrekseydi deposit, Seyitömer-Kütahya, Turkey

    Directory of Open Access Journals (Sweden)

    Murat Hatipoğlu

    2015-03-01

    Full Text Available The strata that include the fine purple opal formations examined in this paper from the magmagenetic hydrothermal dis solutions. The opals are locally known as Gevrekseydi purple opals. These opal-bearing strata are deposited in volcanic lavas and tuffs in the Seyitömer-Kütahya region of western Turkey. The purple opals are common-type and attractive gem-quality, and they are sold on the worldwide gem markets. We conducted mineralogical investigations to clarify their silica building components, measure their nano-size, and determine their origins. The opals are an opal-CT (opal-cristobalite/tridymite- type silica polymorph with the variable number of cristobalite and tridymite layers. The cristobalite and tridymite stacking sequences were evaluated in terms of maturation, crystallite size, and genesis of the opaline silica material. These sequences are modelled using X-ray diffraction patterns. The relationship between the crystallite size and full width at half maximum values of the Gevrekseydi purple opals were also examined using X-ray diffraction patterns. The crystallite sizes were found to be L=17 nm for the main opal-CT peak (4.09 Å, L=23 nm for the shoulder opal-CT peak (4.29 Å, and L=27 nm for the opal-CT/C peak (2.51 Å. Given the relationship between the crystallite size and maturation of opal-CT, the Gevrekseydi volcanic common purple opals are most likely in a stage of early to mid maturation

  4. Utilizing stretch-tunable thermochromic elastomeric opal films as novel reversible switchable photonic materials.

    Science.gov (United States)

    Schäfer, Christian G; Lederle, Christina; Zentel, Kristina; Stühn, Bernd; Gallei, Markus

    2014-11-01

    In this work, the preparation of highly thermoresponsive and fully reversible stretch-tunable elastomeric opal films featuring switchable structural colors is reported. Novel particle architectures based on poly(diethylene glycol methylether methacrylate-co-ethyl acrylate) (PDEGMEMA-co-PEA) as shell polymer are synthesized via seeded and stepwise emulsion polymerization protocols. The use of DEGMEMA as comonomer and herein established synthetic strategies leads to monodisperse soft shell particles, which can be directly processed to opal films by using the feasible melt-shear organization technique. Subsequent UV crosslinking strategies open access to mechanically stable and homogeneous elastomeric opal films. The structural colors of the opal films feature mechano- and thermoresponsiveness, which is found to be fully reversible. Optical characterization shows that the combination of both stimuli provokes a photonic bandgap shift of more than 50 nm from 560 nm in the stretched state to 611 nm in the fully swollen state. In addition, versatile colorful patterns onto the colloidal crystal structure are produced by spatial UV-induced crosslinking by using a photomask. This facile approach enables the generation of spatially cross-linked switchable opal films with fascinating optical properties. Herein described strategies for the preparation of PDEGMEMA-containing colloidal architectures, application of the melt-shear ordering technique, and patterned crosslinking of the final opal films open access to novel stimuli-responsive colloidal crystal films, which are expected to be promising materials in the field of security and sensing applications.

  5. Efficiency enhancement in solid state dye sensitized solar cells by including inverse opals with controlled layer thicknesses

    Science.gov (United States)

    Zheng, Hanbin; Shah, Said Karim; Abbas, Mamatimin; Ly, Isabelle; Rivera, Thomas; Almeida, Rui M.; Hirsch, Lionel; Toupance, Thierry; Ravaine, Serge

    2016-09-01

    The photoconversion efficiency of dye sensitized solar cells can be enhanced by the incorporation of light management nanostructures such as photonic crystals. Here, we present a facile route to incorporate titania inverse opals into solid state dye sensitized solar cells and report photoconversion efficiency enhancements of up to 56% compared with a model system without the inverse opal. Our approach is based on the precise design of titania inverse opals with a predetermined thickness that can be controlled at the individual layer level. By choosing an inverse opal exhibiting a photonic bandgap which overlaps the absorption bands of the dye, our results show that there is an optimal thickness of the inverse opal structure for maximum efficiency enhancement of the cell. This is the first experimental proof that the thickness of a titania inverse opal plays a pivotal role in cell efficiency enhancement in solid state dye sensitized solar cells.

  6. Stable silicon isotope signatures of marine pore waters - Biogenic opal dissolution versus authigenic clay mineral formation

    Science.gov (United States)

    Ehlert, Claudia; Doering, Kristin; Wallmann, Klaus; Scholz, Florian; Sommer, Stefan; Grasse, Patricia; Geilert, Sonja; Frank, Martin

    2016-10-01

    Dissolved silicon isotope compositions have been analysed for the first time in pore waters (δ30SiPW) of three short sediment cores from the Peruvian margin upwelling region with distinctly different biogenic opal content in order to investigate silicon isotope fractionation behaviour during early diagenetic turnover of biogenic opal in marine sediments. The δ30SiPW varies between +1.1‰ and +1.9‰ with the highest values occurring in the uppermost part close to the sediment-water interface. These values are of the same order or higher than the δ30Si of the biogenic opal extracted from the same sediments (+0.3‰ to +1.2‰) and of the overlying bottom waters (+1.1‰ to +1.5‰). Together with dissolved silicic acid concentrations well below biogenic opal saturation, our collective observations are consistent with the formation of authigenic alumino-silicates from the dissolving biogenic opal. Using a numerical transport-reaction model we find that approximately 24% of the dissolving biogenic opal is re-precipitated in the sediments in the form of these authigenic phases at a relatively low precipitation rate of 56 μmol Si cm-2 yr-1. The fractionation factor between the precipitates and the pore waters is estimated at -2.0‰. Dissolved and solid cation concentrations further indicate that off Peru, where biogenic opal concentrations in the sediments are high, the availability of reactive terrigenous material is the limiting factor for the formation of authigenic alumino-silicate phases.

  7. Uraniferous opal, Virgin Valley, Nevada: conditions of formation and implications for uranium exploration

    Science.gov (United States)

    Zielinski, R.A.

    1982-01-01

    Uraniferous, fluorescent opal, which occurs in tuffaceous sedimentary rocks at Virgin Valley, Nevada, records the temperature and composition of uranium-rich solutions as well as the time of uranium-silica coprecipitation. Results are integrated with previous geologic and geochronologic data for the area to produce a model for uranium mobility that may be used to explore for uranium deposits in similar geologic settings. Uraniferous opal occurs as replacements of diatomite, or silicic air-fall ash layers in tuffaceous lakebeds of the Virgin Valley Formation (Miocene) of Merriam (1907). Fission-track radiography shows uranium to be homogeneously dispersed throughout the opal structure, suggesting coprecipitation of dissolved uranium and silica gel. Fluid inclusions preserved within opal replacements of diatomite have homogenization temperatures in the epithermal range and are of low salinity. Four samples of opal from one locality all have U-Pb apparent ages which suggest uraniferous opal precipitation in late Pliocene time. These ages correspond to a period of local, normal faulting, and highangle faults may have served as vertical conduits for transport of deep, thermalized ground water to shallower levels. Lateral migration of rising solutions occurred at intersections of faults with permeable strata. Silica and some uranium were dissolved from silica-rich host strata of 5-20 ppm original uranium content and reprecipitated as the solutions cooled. The model predicts that in similar geologic settings, ore-grade concentrations of uranium will occur in permeable strata that intersect high-angle faults and that contain uranium source rocks as well as efficient reductant traps for uranium. In the absence of sufficient quantities of reductant materials, uranium will be flushed from the system or will accumulate in low-grade disseminated hosts such as uraniferous opal. ?? 1982.

  8. Optical chracterization and lasing in three-dimensional opal-structures

    Directory of Open Access Journals (Sweden)

    Yoshiaki eNishijima

    2015-06-01

    Full Text Available The lasing properties of dye-permeated opal pyramidal structures are compared with the lasing properties of opal films. The opal-structures studied were made by sedimentation of micro-spheres and by sol-gel inversion of the direct-opals. Forced-sedimentation by centrifugation inside wet-etched pyramidal pits on silicon surfaces was used to improve the structural quality of the direct-opal structures. Single crystalline pyramids with the base length of ∼ 100 µm were formed by centrifuged sedimentation. The lasing of dyes in the well-ordered crystalline and poly-crystalline structures showed a distinct multi-modal spectrum. Gain via a distributed feedback was responsible for the lasing since the photonic band gap was negligible in a low refractive index contrast medium; the indices of silica and ethylene glycol are 1.46 and 1.42, respectively. A disordered lasing spectrum was observed from opal films with structural defects and multi-domain regions. The three dimensional structural quality of the structures was assessed by in situ optical diffraction and confocal fluorescence. A correlation between the lasing spectrum and the three-dimensional structural quality was established. Lasing threshold of a sulforhodamine dye in a silica opal was controlled via Förster mechanism by addition of a donor rhodamine 6G dye. The lasing spectrum had a well-ordered modal structure which was spectrally stable at different excitation powers. The sharp lasing threshold characterized by a spontaneous emission coupling ratio β ' 10−2 was obtained.

  9. Open Air Laboratories (OPAL): A community-driven research programme

    Energy Technology Data Exchange (ETDEWEB)

    Davies, L., E-mail: l.davies@imperial.ac.uk [Imperial College London, London SW7 2AZ (United Kingdom); Bell, J.N.B.; Bone, J.; Head, M.; Hill, L. [Imperial College London, London SW7 2AZ (United Kingdom); Howard, C. [Natural History Museum, London SW7 5BD (United Kingdom); Hobbs, S.J. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom); Jones, D.T. [Imperial College London, London SW7 2AZ (United Kingdom); Natural History Museum, London SW7 5BD (United Kingdom); Power, S.A. [Imperial College London, London SW7 2AZ (United Kingdom); Rose, N. [Department of Geography, University College London, London WC1E 6BT (United Kingdom); Ryder, C.; Seed, L. [Imperial College London, London SW7 2AZ (United Kingdom); Stevens, G. [Natural History Museum, London SW7 5BD (United Kingdom); Toumi, R.; Voulvoulis, N. [Imperial College London, London SW7 2AZ (United Kingdom); White, P.C.L. [Environment Department, University of York, Heslington, York YO10 5DD (United Kingdom)

    2011-08-15

    OPAL is an English national programme that takes scientists into the community to investigate environmental issues. Biological monitoring plays a pivotal role covering topics of: i) soil and earthworms; ii) air, lichens and tar spot on sycamore; iii) water and aquatic invertebrates; iv) biodiversity and hedgerows; v) climate, clouds and thermal comfort. Each survey has been developed by an inter-disciplinary team and tested by voluntary, statutory and community sectors. Data are submitted via the web and instantly mapped. Preliminary results are presented, together with a discussion on data quality and uncertainty. Communities also investigate local pollution issues, ranging from nitrogen deposition on heathlands to traffic emissions on roadside vegetation. Over 200,000 people have participated so far, including over 1000 schools and 1000 voluntary groups. Benefits include a substantial, growing database on biodiversity and habitat condition, much from previously unsampled sites particularly in urban areas, and a more engaged public. - Highlights: > Environmental research conducted jointly by the public and scientists. > Over 200,000 people involved, 8000 sites surveyed, uncertainty minimised. > New insights into urban pollution. > A more engaged and informed society. - Research is enriched where the public and scientists work together.

  10. Superconductivity of Bi Confined in an Opal Host

    Science.gov (United States)

    Johnson, R. C.; Nieskoski, M. D.; Disseler, S. M.; Huber, T. E.; Graf, M. J.

    2013-02-01

    Superconductivity is observed in a composite of rhombohedral crystalline bismuth nanoparticles imbedded in an insulating porous opal host via electrical transport and AC magnetic susceptibility. The onset of superconductivity in this system occurs in two steps, with upper transition temperature T c, U =4.1 K and lower transition temperature of T c, L =0.7 K, which we attribute to the granular nature of the composite. The transition at T c, U is observed to split into two transitions with the application of a magnetic field, and these have upper critical fields extrapolated to T=0 K of H c2,1(0)=0.7 T and H c2,2(0)=1.0 T, corresponding to coherence lengths of ξ 1(0)=21 nm and ξ 2(0)=18 nm, respectively. We suggest that because of the lack of bulk-like states in the Bi nanoparticles due to confinement effects, superconductivity originates from surface states arising from Rashba spin-orbit scattering at the interface.

  11. Selectively Patterning Polymer Opal Films via Microimprint Lithography.

    Science.gov (United States)

    Ding, Tao; Zhao, Qibin; Smoukov, Stoyan K; Baumberg, Jeremy J

    2014-11-01

    Large-scale structural color flexible coatings have been hard to create, and patterning color on them is key to many applications, including large-area strain sensors, wall-size displays, security devices, and smart fabrics. To achieve controlled tuning, a micro-imprinting technique is applied here to pattern both the surface morphology and the structural color of the polymer opal films (POFs). These POFs are made of 3D ordered arrays of hard spherical particles embedded inside soft shells. The soft outer shells cause the POFs to deform upon imprinting with a pre-patterned stamp, driving a flow of the soft polymer and a rearrangement of the hard spheres within the films. As a result, a patterned surface morphology is generated within the POFs and the structural colors are selectively modified within different regions. These changes are dependent on the pressure, temperature, and duration of imprinting, as well as the feature sizes in the stamps. Moreover, the pattern geometry and structural colors can then be further tuned by stretching. Micropattern color generation upon imprinting depends on control of colloidal transport in a polymer matrix under shear flow and brings many potential properties including stretchability and tunability, as well as being of fundamental interest.

  12. Kinetic parameters calculation and measurements during the OPAL commissioning

    Energy Technology Data Exchange (ETDEWEB)

    Hergenreder, D.F.; Lecot, C.A.; Villarino, E.A. [INVAP S.E., Nuclear Projects Dept., Nuclear Engineering Div., Rio Negro (Argentina)

    2007-07-01

    During the Commissioning Stage of the OPAL Research Reactor (Australia) the Prompt Neutron Decay constant ({alpha}) was measured by analysing the inherent fluctuations that occur in the neutron population. The ratio of the variance to the mean number of counts as a function of counting time is used to determine experimentally the {alpha} parameter. This technique is also called Feynman-{alpha} Method. The CITVAP and MCNP codes were used to calculate the prompt neutron decay constant for the first core configuration. By means of two different MCNP calculations, one considering prompt fission neutrons only and another with total fission neutrons; the effective delayed neutron fraction is estimated. The experimental method, the measured value as well as the numerical assessment are presented in this paper. A good agreement was obtained between measurements and calculations, particularly it is worth noticing that the measured value for the {alpha} parameter, when {rho} = 0, is 38.1 s{sup -1} while the calculated value is 37.2 s{sup -1}.

  13. Practitioner insights on obesity prevention: the voice of South Australian OPAL workers.

    Science.gov (United States)

    2016-06-01

    Knowledge based on science has been central to implementing community-based childhood obesity prevention interventions. The art of practitioner wisdom is equally critical to ensure locally relevant responses. In South Australia (SA), the OPAL (Obesity Prevention and Lifestyle) program has been implemented to reduce childhood obesity across 20 communities reaching nearly one quarter of the state's population. Staff from across the State come together at regular intervals to share practice challenges and insights and refine the model of practice. Over a 3-year period 12 reflective practice workshops were held with OPAL staff (n = 46). OPAL staff were guided by an external facilitator using inquiring questions to reflect on their health promotion practice within local government. Three themes were identified as central within the reflections. The first theme is shared clarity through the OPAL obesity prevention model highlighting the importance of working to a clearly articulated, holistic obesity prevention model. The second theme is practitioner skill and sensitivity required to implement the model and deal with the 'politics' of obesity prevention. The final theme is the power of relationships as intrinsic to effective community based health promotion. Insights into the daily practices and reflections from obesity prevention practitioners are shared to shed light on the skills required to contribute to individual and social change. OPAL staff co-authored this paper.

  14. Er3+-activated silica inverse opals synthesized by the solgel method

    Institute of Scientific and Technical Information of China (English)

    A. Chiappini; L. Zampedri; G. Nunzi Conti; S. Pelli; R. M. Almeida; G. C. Righini; C.Armellini; A. Chiasera; Y. Jestin; M. Ferrari; M. Mattarelli; M. Montagna; E. Moser; C. Tosello

    2007-01-01

    We present the details of the sol-gel processing used to realize inverse silica opal, where the silica was activated with 0.3 mol% of Er3+ ions. The template (direct opal) was obtained assembling polystyrene spheres of the dimensions of 260 nm by means of a vertical deposition technique. The Er3+-activated silica inverse opal was obtained infiltrating, into the void of the template, the silica sol doped with Er3+ ions and subsequently removing the polystyrene spheres by means of calcinations.Scanning electron microscope showed that the inverse opals possess a fcc structure with a air hollows of about 210 nm and a photonic band gap, in the visible range, was observed from reflectance measurements. Spectroscopic properties of Er3+-activated silica inverse opal were investigated by luminescence spectroscopy, where, upon excitation at 514.5 nm, an emission of 4I13/2 → 4I15/2 of Er3+ ions transition with a 21 nm bandwidth was observed. Moreover the 4I13/2 level decay curve presents a single-exponential profile, with a measured lifetime of 18 ms, corresponding a high quantum efficiency of the system.

  15. Thermally Driven Photonic Actuator Based on Silica Opal Photonic Crystal with Liquid Crystal Elastomer.

    Science.gov (United States)

    Xing, Huihui; Li, Jun; Shi, Yang; Guo, Jinbao; Wei, Jie

    2016-04-13

    We have developed a novel thermoresponsive photonic actuator based on three-dimensional SiO2 opal photonic crystals (PCs) together with liquid crystal elastomers (LCEs). In the process of fabrication of such a photonic actuator, the LCE precursor is infiltrated into the SiO2 opal PC followed by UV light-induced photopolymerization, thereby forming the SiO2 opal PC/LCE composite film with a bilayer structure. We find that this bilayer composite film simultaneously exhibits actuation behavior as well as the photonic band gap (PBG) response to external temperature variation. When the SiO2 opal PC/LCE composite film is heated, it exhibits a considerable bending deformation, and its PBG shifts to a shorter wavelength at the same time. In addition, this actuation is quite fast, reversible, and highly repeatable. The thermoresponsive behavior of the SiO2 opal PC/LCE composite films mainly derives from the thermal-driven change of nematic order of the LCE layer which leads to the asymmetric shrinkage/expansion of the bilayer structure. These results will be of interest in designing optical actuator systems for environment-temperature detection.

  16. The optical interface of a photonic crystal: Modeling an opal with a stratified effective index

    CERN Document Server

    Maurin, Isabelle; Laliotis, Athanasios; Bloch, Daniel

    2014-01-01

    An artificial opal is a compact arrangement of transparent spheres, and is an archetype of a three-dimensional photonic crystal. Here, we describe the optics of an opal using a flexible model based upon a stratified medium whose (effective) index is governed by the opal density in a small planar slice of the opal. We take into account the effect of the substrate and assume a well- controlled number of layers, as it occurs for an opal fabricated by Langmuir-Blodgett deposition. The calculations are performed with transfer matrices, and an absorptive component in the effective index is introduced to account for the light scattering. This one-dimensional formalism allows quantitative predictions for reflection and transmission, notably as a function of the ratio between the irradiation wavelength and the sphere diameter, or as a function of the incidence angle or of the polarization. It can be used for an irradiation from the substrate side or from the vacuum side and can account for defect layers. The interface...

  17. Diagenetic Microcrystalline Opal Varieties from the Monterey Formation, CA: HRTEM Study of Structures and Phase Transformation Mechanisms

    Science.gov (United States)

    Cady, Sherry L.; Wenk, H.-R.; DeVincenzi, Don (Technical Monitor)

    1994-01-01

    Microcrystalline opal varieties form as intermediary precipitates during the diagenetic transformation of biogenically precipitated non-crystalline opal (opal-A) to microquartz. With regard to the Monterey Formation of California, X-ray powder diffraction studies have shown that a decrease in the primary d-spacing of opal-CT toward that of cristobalite occurs with increasing diagenesis. The initial timing of opal-CT/quartz formation and the value of the primary opal-CT d-spacing, are influenced by the sediment. lithology. Transmission electron microscopy methods (CTEM/HRTEM) were used to investigate the structure of the diagenetic phases and establish transformation mechanisms between the varieties of microcrystalline opals in charts and porcelanites from the Monterey Formation. HRTEM images revealed that the most common fibrous varieties of microcrystalline opals contain varying amounts of structural disorder. Finite lamellar units of cristobalite-and tridymite-type. layer sequences were found to be randomly stacked in a direction perpendicular to the fiber axis. Disordered and ordered fibers were found to have coprecipitated within the same radial fiber bundles that formed within the matrix of the Most siliceous samples. HRTEM images, which reveal that the fibers within radial and lepispheric fiber bundles branch non-crystallographically, support an earlier proposal that microspheres in chert grow via a spherulitic growth mechanism. A less common variety of opal-CT was found to be characterized by non-parallel (low-angle) stacking sequences that often contain twinned lamellae. Tabular-shaped crystals of orthorhombic tridymite (PO-2) were also identified in the porcelanite samples. A shift in the primary d-spacing of opal-CT has been interpreted as an indication of solid-state ordering g toward a predominantly cristobalite structure, (opal-C). Domains of opal-C were identified as topotactically-oriented overgrowths on discrete Sections of opal-CT fibers and as

  18. Resonant infiltration of an opal: Reflection line shape and contribution from in-depth regions.

    Science.gov (United States)

    Maurin, Isabelle; Bloch, Daniel

    2015-06-21

    We analyze the resonant variation of the optical reflection on an infiltrated artificial opal made of transparent nanospheres. The resonant infiltration is considered as a perturbation in the frame of a previously described one-dimensional model based upon a stratified effective index. We show that for a thin slice of resonant medium, the resonant response oscillates with the position of this slice. We derive that for adequate conditions of incidence angle, this spatially oscillating behavior matches the geometrical periodicity of the opal and hence the related density of resonant infiltration. Close to these matching conditions, the resonant response of the global infiltration varies sharply in amplitude and shape with the incidence angle and polarization. The corresponding resonant reflection originates from a rather deep infiltration, up to several wavelengths or layers of spheres. Finally, we discuss the relationship between the present predictions and our previous observations on an opal infiltrated with a resonant vapor.

  19. Fabrication of BaTiO3 Inverse Opal Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    An XIANG; Jian Ping GAO; Hong Kui CHEN; Jiu Gao YU; Rui Xian LIU

    2004-01-01

    The colloidal crystal template or opal with a closed-packed face centered cubic (fcc) lattice, was prepared from monodisperse polystyrene (PS) spheres by gravity sedimentation. The template was used for the generation of photonic crystal. The template provided void space for infiltration of liquid precursor composed of titanium butyloxide, barium acetate, ethanol, and acetic acid. The opal composite was hydrolyzed, dried, sintered by heating for completely removing PS spheres to form BaTiO3 photonic crystals with inverse opal structure. The PS spheres were replaced by air spheres, which interconnected each other through the windows on the BaTiO3 wall. So both the BaTiO3 wall and air void constitute continuous phases.

  20. PAM-PAA microgel inverse opal photonic crystal and pH response

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The colloidal crystal template or opal with a closed-packed face-centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) spheres by vertical sedimentation. The template provided void space for infiltration of monomer precursor composed of acrylate acid, acrylamide and ammonium persulfate, as well as microgel from the subsequent copolymerization. The sample was immersed in dimethylbenzene for completely removing PS spheres to form PAM inverse opal hydrogels (IOHPAM) or PAM/PAA inverse opal hydrogels (IOHPAM/PAA) photonic crystals. The PS spheres were replaced by air spheres, which interconnected each other through the windows. The study of responses to pH show that there are two peaks for both IOHPAM and IOHPAM/PAA films, but the IOHPAM/PAA peaks shift to higher pH, and the peaks are independent with the AA content.

  1. Optical analysis of the fine crystalline structure of artificial opal films.

    Science.gov (United States)

    Lozano, G; Dorado, L A; Schinca, D; Depine, R A; Míguez, H

    2009-11-17

    Herein, we present a detailed analysis of the structure of artificial opal films. We demonstrate that, rather than the generally assumed face centered cubic lattice of spheres, opal films are better approximated by rhombohedral assemblies of distorted colloids. Detailed analysis of the optical response in a very wide spectral range (0.4 < or = a/lambda < or = 2, where a is the conventional lattice constant), as well as at perpendicular and off-normal directions, unambiguously shows that the interparticle distance coincides very approximately with the expected diameter only along directions contained in the same close-packed plane but differs significantly in directions oblique to the [111] one. A full description of the real and reciprocal lattices of actual opal films is provided, as well as of the photonic band structure of the proposed arrangement. The implications of this distortion in the optical response of the lattice are discussed.

  2. Optical link design and validation testing of the Optical Payload for Lasercomm Science (OPALS) system

    Science.gov (United States)

    Oaida, Bogdan V.; Wu, William; Erkmen, Baris I.; Biswas, Abhijit; Andrews, Kenneth S.; Kokorowski, Michael; Wilkerson, Marcus

    2014-03-01

    The Optical Payload for Lasercomm Science (OPALS) system developed by the Jet Propulsion Laboratory, California Institute of Technology, will be used for optical telecommunications link experiments from the International Space Station (ISS) to a ground telescope located at Table Mountain, CA. The launch of the flight terminal is scheduled for late February 2014 with an initially planned 90-day operations period following deployment on the exterior of the ISS. The simple, low-cost OPALS system will downlink a pre-encoded video file at 50 Mb/s on a 1550 nm laser carrier using on-off key (OOK) modulation and Reed-Solomon forward error correction. A continuous wave (cw) 976 nm multibeam laser beacon transmitted from the ground to the ISS will initiate link acquisition and tracking by the flight subsystem. Link analysis along with pre-flight results of the end-to-end free-space testing of the OPALS link are presented.

  3. Resonant infiltration of an opal: reflection lineshape and contribution from in-depth regions

    CERN Document Server

    Maurin, Isabelle

    2015-01-01

    We analyze the resonant variation of the optical reflection on an infiltrated artificial opal made of transparent nanospheres. The resonant infiltration is considered as a perturbation in the frame of a previously described one-dimensional model based upon a stratified effective index. We show that for a thin slice of resonant medium, the resonant response oscillates with the position of this slice. We derive that for adequate conditions of incidence angle, this spatially oscillating behavior matches the geometrical periodicity of the opal, and hence the related density of resonant infiltration. Close to these matching conditions, the resonant response of the global infiltration varies sharply in amplitude and shape with the incidence angle and polarization. The corresponding resonant reflection originates from a rather deep infiltration, up to several wavelengths or layers of spheres. Finally, we discuss the relationship between the present predictions and our previous observations on an opal infiltrated wit...

  4. Color Tunable and Upconversion Luminescence in Yb-Tm Co-Doped Yttrium Phosphate Inverse Opal Photonic Crystals.

    Science.gov (United States)

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2016-04-01

    For this paper, YPO4: Tm, Yb inverse opals with the photonic band gaps at 475 nm and 655 nm were prepared by polystyrene colloidal crystal templates. We investigated the influence of photonic band gaps on the Tm-Yb upconversion emission which was in the YPO4: Tm Yb inverse opal photonic crystals. Comparing with the reference sample, significant suppression of both the blue and red upconversion luminescence of Tm3+ ions were observed in the inverse opals. The color purity of the blue emission was improved in the inverse opal by the suppression of red upconversion emission. Additionally, mechanism of upconversion emission in the inverse opal was discussed. We believe that the present work will be valuable for not only the foundational study of upconversion emission modification but also the development of new optical devices in upconversion lighting and display.

  5. Spectroscopy of stop bands in artificial opals filled with an alcohol solution of potassium iodide

    Science.gov (United States)

    Gorelik, V. S.; Filatov, V. V.

    2012-09-01

    The spectral position of the stop bands in photonic crystals based on artificial opals filled with an alcohol solution of potassium iodide is investigated. The energy-band structure of samples with quartz globules 230 nm in diameter is modeled based on the dispersion equation. The spectral position of the stop bands in the [111] direction at different solution concentrations is determined. The conditions for forbidden-band "collapse" are established. The possibility of applying artificial opals in optical cavities of lasers of different types is analyzed.

  6. Chemically Patterned Inverse Opal Created by a Selective Photolysis Modification Process.

    Science.gov (United States)

    Tian, Tian; Gao, Ning; Gu, Chen; Li, Jian; Wang, Hui; Lan, Yue; Yin, Xianpeng; Li, Guangtao

    2015-09-01

    Anisotropic photonic crystal materials have long been pursued for their broad applications. A novel method for creating chemically patterned inverse opals is proposed here. The patterning technique is based on selective photolysis of a photolabile polymer together with postmodification on released amine groups. The patterning method allows regioselective modification within an inverse opal structure, taking advantage of selective chemical reaction. Moreover, combined with the unique signal self-reporting feature of the photonic crystal, the fabricated structure is capable of various applications, including gradient photonic bandgap and dynamic chemical patterns. The proposed method provides the ability to extend the structural and chemical complexity of the photonic crystal, as well as its potential applications.

  7. Nanocomposites based on opal matrixes with 3D-structure formed by mangnetic nanoparticles

    Directory of Open Access Journals (Sweden)

    Rinkevich A. B.

    2008-08-01

    Full Text Available Interaction of electromagnetic waves with nanocomposites of materials obtained by doping of opal matrixes with nickel-zinc and manganese-zinc ferrite has been studied. The opal matrixes contain of SiO2 nanospheres with diameter about 250 nm with ferrite nanoparticles in the nanosphere voids. The measurements are carried out in frequency range from 26 to 38 GHz in magnetic fields up to 30 kOe. It was shown that magnetic resonance in the doped matrix is the main reason for microwave variations.

  8. Permanent tuning of the opal stop-band with the application of uniaxial pressure

    Science.gov (United States)

    Khokhar, Ali Z.; DeLa Rue, Richard M.; Ren, Kun; Li, Zhi-Yuan; Johnson, Nigel P.

    2007-05-01

    Three-dimensional photonic crystals have been prepared by self-assembly from sub-micrometre polystyrene spheres. Such crystals are known as a synthetic opal and possess a partial stop-band in the \\langle 111\\rangle direction. The stop-band is tuned towards the shorter wavelengths by applying uniaxial pressure along the \\langle 111\\rangle direction of the face-centred cubic opal structure. The tuning is found to be irreversible and it was also observed that the normalized stop-bandwidth increased after applying uniaxial pressure. The experimental results are compared with the simulation results and found to be in very close agreement.

  9. Mesozooplankton biomass and grazing responses to Cyclone Opal, a subtropical mesoscale eddy

    Science.gov (United States)

    Landry, Michael R.; Decima, Moira; Simmons, Melinda P.; Hannides, Cecelia C. S.; Daniels, Emy

    2008-05-01

    As part of E-Flux III cruise studies in March 2005, plankton net collections were made to assess the effects of a cyclonic cold-core eddy (Cyclone Opal) on the biomass and grazing of mesozooplankton. Mesozooplankton biomass in the central region of Cyclone Opal, an area of uplifted nutricline and a subsurface diatom bloom, averaged 0.80±0.24 and 1.51±0.59 g DW m -2, for day and night tows, respectively. These biomass estimates were about 80% higher than control (OUT) stations, with increases more or less proportionately distributed among size classes from 0.2 to >5 mm. Though elevated relative to surrounding waters south of the Hawaiian Islands (Hawai'i lee), total biomass and size distribution in Cyclone Opal were almost exactly the same as contemporary measurements made at Stn. ALOHA, 100 km north of the islands, by the HOT (Hawaii Ocean Time-series) Program. Mesozooplankton biomass and community composition at the OUT stations were also similar to ALOHA values from 1994 to 1996, preceding a recent decadal increase. These comparisons may therefore provide insight into production characteristics or biomass gradients associated with decadal changes at Stn. ALOHA. Gut fluorescence estimates were higher in Opal than in ambient waters, translating to grazing impacts of 0.11±0.02 d -1 (IN) versus 0.03±0.01 d -1 (OUT). Over the depth-integrated euphotic zone, mesozooplankton accounted for 30% of the combined grazing losses of phytoplankton to micro- and meso-herbivores in Opal, as compared to 13% at control stations. Estimates of active export flux by migrating zooplankton averaged 0.81 mmol C m -2 d -1 in Cyclone Opal and 0.37 mmol C m -2 d -1 at OUT stations, 53% and 24%, respectively, of the carbon export measured by passive sediment traps. Migrants also exported 0.18 mmol N m -2 d -1 (117% of trap N flux) in Cyclone Opal compared to 0.08 mmol N m -2 d -1 (51% of trap flux) at control stations. Overall, the food-web importance of mesozooplankton increased in

  10. Automated spray coating process for the fabrication of large-area artificial opals on textured substrates.

    Science.gov (United States)

    Sprafke, Alexander N; Schneevoigt, Daniela; Seidel, Sophie; Schweizer, Stefan L; Wehrspohn, Ralf B

    2013-05-06

    3D photonic crystals, such as opals, have been shown to have a high potential to increase the efficiency of solar cells by enabling advanced light management concepts. However, methods which comply with the demands of the photovoltaic industry for integration of these structures, i. e. the fabrication in a low-cost, fast, and large-scale manner, are missing up to now. In this work, we present the spray coating of a colloidal suspension on textured substrates and subsequent drying. We fabricated opaline films of much larger lateral dimensions and in much shorter times than what is possible using conventional opal fabrication methods.

  11. Ornamental Stones and Gemstones: The limits of heritage stone designation: The case for and against Australian Precious Opal

    Science.gov (United States)

    Cooper, Barry

    2015-04-01

    When the international designation of natural stone types was first mooted in 2007, stones that were utilised in building and construction were the primary focus of attention. However following public discussion it soon became apparent that sculptural stones, stone used for utilitarian purposes such as millstones, as well as archaeological materials including stones used by early man could all be positively assessed as a potential Global Heritage Stone Resource (GHSR). Over the past 2 years it has been realised there is also a range of ornamental and semi-precious stones that may also be considered in the same international context. Examples in this respect include Imperial Porphyry sourced from Egypt that was much prized in the ancient world and "Derbyshire Blue John" a variety of fluorspar from central England that was used for vases, chalices, urns, candle sticks, jars, bowls door, jewellery and fire-place surrounds, especially in the 18th and 19th centuries. It is at this point that rock materials, sometimes used as gemstones, impinge on the domain of typical heritage stones. In Australia, the gemstone most identifiable with the country is precious opal formed by sedimentary processes in the Great Artesian Basin. In this paper the question is asked whether "Australian Precious Opal" could be or should be considered as a heritage stone of international significance. Immediately Australian Precious Opal satisfies several GHSR criteria including historic use for more than 50 years and wide-ranging utilisation for prestige jewellery around the world. It is also recognised as a cultural icon including association with national identity in Australia as it is legally defined as Australia's "National Gemstone" as well as being the "Gemstone Emblem" for the State of South Australia. Opal continues to be mined. Designation of Australian Precious Opal as a Global Heritage Stone Resource would likely involve formal international recognition of Australian opal in the

  12. Infiltrating a thin or single layer opal with an atomic vapour: sub-doppler signals and crystal optics

    CERN Document Server

    Moufarej, Elias; Zabkov, Ilya; Laliotis, Athanasios; Ballin, Philippe; Klimov, Vasily; Bloch, Daniel

    2014-01-01

    Artificial thin glass opals can be infiltrated with a resonant alkali-metal vapour, providing novel types of hybrid systems. The reflection at the interface between the substrate and the opal yields a resonant signal, which exhibits sub-Doppler structures in linear spectroscopy for a range of oblique incidences. This result is suspected to originate in an effect of the three-dimensional confinement of the vapour in the opal interstices. It is here extended to a situation where the opal is limited to a few or even a single layer opal film, which is a kind of bidimensional grating. We have developed a flexible one-dimensional layered optical model, well suited for a Langmuir-Blodgett opal. Once extended to the case of a resonant infiltration, the model reproduces quick variations of the lineshape with incidence angle or polarization. Alternately, for an opal limited to a single layer of identical spheres, a three-dimensional numerical calculation was developed. It predicts crystalline anisotropy, which is demon...

  13. Two-dimensional inverse opal hydrogel for pH sensing.

    Science.gov (United States)

    Xue, Fei; Meng, Zihui; Qi, Fenglian; Xue, Min; Wang, Fengyan; Chen, Wei; Yan, Zequn

    2014-12-01

    A novel hydrogel film with a highly ordered macropore monolayer on its surface was prepared by templated photo-polymerization of hydrogel monomers on a two-dimensional (2D) polystyrene colloidal array. The 2D inverse opal hydrogel has prominent advantages over traditional three-dimensional (3D) inverse opal hydrogels. First, the formation of the 2D array template through a self-assembly method is considerably faster and simpler. Second, the stable ordering structure of the 2D array template makes it easier to introduce the polymerization solution into the template. Third, a simple measurement, a Debye diffraction ring, is utilized to characterize the neighboring pore spacing of the 2D inverse opal hydrogel. Acrylic acid was copolymerized into the hydrogel; thus, the hydrogel responded to pH through volume change, which resulted from the formation of the Donnan potential. The 2D inverse opal hydrogel showed that the neighboring pore spacing increased by about 150 nm and diffracted color red-shifted from blue to red as the pH increased from pH 2 to 7. In addition, the pH response kinetics and ionic strength effect of this 2D mesoporous polymer film were also investigated.

  14. Green Color Purification in Tb(3+) Ions through Silica Inverse Opal Heterostructure.

    Science.gov (United States)

    Shrivastava, Vishnu Prasad; Sivakumar, Sri; Kumar, Jitendra

    2015-06-10

    The ordered SiO2:Tb(3+) inverse opal heterostructure films are fabricated through polystyrene spheres hetero-opal template using the convective self-assembly method to examine their potential for color purification. Their optical properties and photoluminescence have been investigated and compared with individual single inverse opals and reference (SiO2:Tb(3+) powder). The heterostructures are shown to possess two broad photonic stop bands separated by an effective pass band, causing suppression of blue, orange, and red emission bands corresponding to (5)D4 → (7)F(j); j = 6, 4, 3 transitions, respectively and an enhancement of green emission (i.e., (5)D4 → (7)F5). Although the suppression of various emission occurs because of its overlap with the photonic band gaps (PSBs), the enhancement of green radiation is observed because of its location matching with the pass band region. The Commission International de l'Eclairage (CIE) chromaticity coordinates of the emission spectrum of the heterostructure based on polystyrene sphere of 390 and 500 nm diameter are x = 0.2936, y = 0.6512 and lie closest to those of standard green color (wavelength 545 nm). In addition, a significant increase observed in luminescence lifetime for (5)D4 level of terbium in inverse opal heterostructures vis-à-vis reference (SiO2:Tb(3+) powder) is attributed to the change in the effective refractive index.

  15. Metal-induced fluorescence properties of three-dimensionally ordered macroporous silver inverse opal platforms

    Science.gov (United States)

    Chae, Weon-Sik; Lee, Myung-Jin; Kim, Kisun; Hyun, Jerome K.; Jeon, Seokwoo

    2016-02-01

    This study examined the metal-induced fluorescence properties of three-dimensionally ordered macroporous silver inverse opal (IO) films. Electrochemically synthesized silver IO films with a micrometer cavity exhibited notable fluorescence enhancement at the silver frame, and a decrease in fluorescence lifetime. Numerical calculations supported the observations of a higher fluorescence efficiency at the frame than in the cavity.

  16. Study of the structure of synthetic opals affected by temperature and pressure

    Science.gov (United States)

    Somenkov, V. A.; Agafonov, S. S.; Glazkov, V. P.; Kovalenko, E. S.; Shushunov, M. N.

    2015-01-01

    It is demonstrated that synthetic opals, like most natural ones, have a cristobalite rather than quartz basis, change their color from white to blue after losing their water-containing component, and form superlattices. Being affected by temperature and pressure, they undergo partial or complete crystallization to the corresponding polymorphic modifications.

  17. Magnetic topology of Co-based inverse opal-like structures

    NARCIS (Netherlands)

    Grigoryeva, N.A.; Mistonov, A.A.; Napolskii, K.S.; Sapoletova, N.A.; Eliseev, A.A.; Bouwman, W.; Byelov, D.; Petukhov, A.V.; Chernyshov, D.Y.; Eckerlebe, H.; Vasilieva, A.V.; Grigoriev, S.V.

    2011-01-01

    Themagnetic and structural properties of a cobalt inverse opal-like crystal have been studied by a combination of complementary techniques ranging from polarized neutron scattering and superconducting quantum interference device (SQUID) magnetometry to x-ray diffraction. Microradian small-angle x-ra

  18. Magnetic topology of Co-based inverse opal-like structures

    NARCIS (Netherlands)

    Grigoryeva, N.A.; Mistonov, A.A.; Napolskii, K.S.; Sapoletova, N.A.; Eliseev, A.A.; Bouwman, W.G.; Byelov, D.V.; Petukhov, A.V.; Chernyshov, D.Y.; Eckerlebe, H.; Vasilieva, A.V.; Grigoriev, S.V.

    2011-01-01

    The magnetic and structural properties of a cobalt inverse opal-like crystal have been studied by a combination of complementary techniques ranging from polarized neutron scattering and superconducting quantum interference device (SQUID) magnetometry to x-ray diffraction. Microradian small-angle x-r

  19. Radiation monitoring and beam dump system of the OPAL silicon microvertex detector

    CERN Document Server

    Braibant, S

    1997-01-01

    The OPAL microvertex silicon detector radiation monitoring and beam dump system is described. This system was designed and implemented in order to measure the radiation dose received at every beam crossing and to induce a fast beam dump if the radiation dose exceeds a given threshold.

  20. OPAL REACTOR: Calculation/Experiment comparison of Neutron Flux Mapping in Flux Coolant Channels

    Energy Technology Data Exchange (ETDEWEB)

    Barbot, L.; Domergue, C.; Villard, J. F.; Destouches, C. [CEA, Paris (France); Braoudakis, G.; Wassink, D.; Sinclair, B.; Osborn, J. C.; Huayou, Wu [ANSTO, Syeney (Australia)

    2013-07-01

    The measurement and calculation of the neutron flux mapping of the OPAL research reactor are presented. Following an investigation of fuel coolant channels using sub-miniature fission chambers to measure thermal neutron flux profiles, neutronic calculations were performed. Comparison between calculation and measurement shows very good agreement.

  1. Diamond Opal-Replica Photonic Crystals and Graphitic Metallic Photonic Band Gap Structures: Fabrication and Properties

    Science.gov (United States)

    Zakhidov, A. A.; Baughman, R. H.; Iqbal, Z.; Khayrullin, I. I.; Ralchenko, V. G.

    1998-03-01

    We demonstrate a new method for the formation of photonic bandgap crystals that operate at optical wavelengths. This method involves the templating of a self-assempled SiO2 lattice with diamond, graphite, or amorphous forms of carbon, followed by the removal of the original SiO2 lattice matrix by chemical means. Such carbon opal replicas are the "air type" of photonic crystal (where air replaces silica spheres) that are most favourable for photonic bandgap formation. Surprisingly, the structure of the original opal lattice having a typical cubic lattice dimension of 250 nm) is reliably replicated down to the nanometer scale using either a diamond, graphite, or amorphous carbon templated material. The optical properties of these photonic bandgap crystals are reported and compared with both theory and experimental results on other types of opal-derived lattices that we have investigated. The graphitic reverse opal is the first example of a network type metallic photonic crystal for the optical domain, for which a large photonic bandgap have been predicted.

  2. Focused ion beam milling of nanocavities in single colloidal particles and self-assembled opals

    NARCIS (Netherlands)

    Woldering, Leon A.; Otter, A.M.(Bert); Husken, Bart H.; Vos, Willem L.

    2006-01-01

    We present a new method of realizing single nanocavities in individual colloidal particles on the surface of silicon dioxide artificial opals using a focused ion beam milling technique. We show that both the radius and the position of the nanocavity can be controlled with nanometre precision, to rad

  3. Quaternary high-resolution opal record and its paleopro- ductivity implication at ODP Site 1143, southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The correlation of opal content and MAR with oxygen isotopic records of benthonic foraminifera at Site 1143, southern South China Sea indicates that, since about 900 ka, the increasing opal content and MAR during the interglacial periods is inferred to reflect the higher surface productivity, for the intensified summer monsoon during the interglacial periods would result in the enhanced upwelling and nutrient supply. Time-sequence spectral analyses of oxygen isotopic record, opal content and MAR at intervals of 0-900 ka reveal that the changes of surface productivity were dominantly forced by the variations of the earth orbital cycles.

  4. The Optical Profiling of the Atmospheric Limb (OPAL) CubeSat Experiment

    Science.gov (United States)

    Jeppesen, M.; Miller, J.; Cox, W.; Taylor, M. J.; Swenson, C.; Neilsen, T. L.; Fish, C. S.; Scherliess, L.; Christensen, A. B.; Cleave, M.

    2015-12-01

    The Earth's lower thermosphere is an important interface region between the neutral atmosphere and the "space weather" environment. While the high-latitude region of the thermosphere responds promptly to energy inputs, relatively little is known about the global/regional response to these energy inputs. Global temperatures are predicted to respond within 3-6 hours, but the details of the thermal response of the atmosphere as energy transports away from high-latitude source regions is not well understood. The Optical Profiling of the Atmospheric Limb (OPAL) mission aims to characterize this thermal response through observation of the temperature structure of the lower thermosphere at mid- and low-latitudes. The OPAL instrument is designed to map global thermospheric temperature variability over the critical "thermospheric gap" region (~100-140 km altitude) by spectroscopic analysis of molecular oxygen A-band emission (758 - 768 nm). The OPAL instrument is a grating-based imaging spectrometer with refractive optics and a high-efficiency volume holographic grating (VHG). The scene is sampled by 7 parallel slits that form non-overlapping spectral profiles at the focal plane with resolution of 0.5 nm (spectral), 1.5 km (limb profiling), and 60 km (horizontal sampling). A CCD camera at the instrument focal plane delivers low noise and high sensitivity. The instrument is designed to strongly reject stray light from daylight regions of the earth. The OPAL mission is funded by the National Science Foundation (NSF) CubeSat-based Science Missions for Geospace and Atmospheric Research program. The OPAL instrument, CubeSat bus and mission are being designed, built and executed by a team comprised of students and professors from Utah State University, Dixie State University and the University of Maryland Eastern Shore, with support from professional scientists and engineers from the Space Dynamics Laboratory and Hawk Institute for Space Science.

  5. The computer application for the opal breccia deposit performance: the discreet interpolation or the finite diferences method

    OpenAIRE

    2003-01-01

    The application of discreet interpolation or the finite differences methods for opal breccia deposit. The performance is carried out by computer application and graphical presentation for quartz and aluminium oxide.

  6. Low temperature catalytic combustion of propane over Pt-based catalyst with inverse opal microstructure in a microchannel reactor.

    Science.gov (United States)

    Guan, Guoqing; Zapf, Ralf; Kolb, Gunther; Men, Yong; Hessel, Volker; Loewe, Holger; Ye, Jianhui; Zentel, Rudolf

    2007-01-21

    A novel Pt-based catalyst with highly regular, periodic inverse opal microstructure was fabricated in a microchannel reactor, and catalytic testing revealed excellent conversion and stable activity for propane combustion at low temperatures.

  7. Spontaneous emission of semiconductor quantum dots in inverse opal SiO2 photonic crystals at different temperatures.

    Science.gov (United States)

    Yang, Peng; Yang, Yingshu; Wang, Yinghui; Gao, Jiechao; Sui, Ning; Chi, Xiaochun; Zou, Lu; Zhang, Han-Zhuang

    2016-02-01

    The photoluminescence (PL) characteristics of CdSe quantum dots (QDs) infiltrated into inverse opal SiO2 photonic crystals (PCs) are systemically studied. The special porous structure of inverse opal PCs enhanced the thermal exchange rate between the CdSe QDs and their surrounding environment. Finally, inverse opal SiO2 PCs suppressed the nonlinear PL enhancement of CdSe QDs in PCs excited by a continuum laser and effectively modulated the PL characteristics of CdSe QDs in PCs at high temperatures in comparison with that of CdSe QDs out of PCs. The final results are of benefit in further understanding the role of inverse opal PCs on the PL characteristics of QDs.

  8. Photoluminescence and energy transfer investigation from SiO2: Tb, Au inverse opals to rhodamine-B dyes

    Science.gov (United States)

    Yang, Jianzhi; Yang, Zhengwen; Wang, Yida; Qiu, Jianbei; Song, Zhiguo

    2016-10-01

    Energy transfer has attracted extensive attention due to its widespread applications in medical diagnostics, DNA analysis and lighting devices. There are few reports on the energy transfer from rare earth ions to dyes. In the present work, the SiO2:Tb inverse opals with and without Au nanoparticles were prepared, and the organic rhodamine-B (RhB) dyes were filled into the voids of SiO2:Tb inverse opals. Non-radiative and radiative energy transfer processes from the SiO2:Tb inverse opals to the RhB were observed. The influence of Au nanoparticles and photonic band gap on the energy transfer from SiO2:Tb inverse opals to the RhB was investigated. The Au nanoparticles enhanced energy transfer was observed due to the surface plasmon resonance effects of the Au nanoparticles. When the emission peaks from the SiO2:Tb inverse opal is overlapped with the photonic band gap, the emission suppression of the SiO2:Tb inverse opal as well the emission enhancement of the RhB dyes were obtained, which is attributed to improved energy transfer caused by the photonic band gap. The steady state rate equations were used to explain enhancement of energy transfer caused by the photonic band gap.

  9. 不同品种授粉对Opal Star费约果着果及果实品质的影响

    Institute of Scientific and Technical Information of China (English)

    秦晓旭; 张猛; 王丹; 李泽华

    2015-01-01

    Opal Star费约果为母本,分别授以Unique、Mammoth、Coolidge、Triumph品种的花粉,探讨不同品种对Opal Star着果及果实品质的影响.结果表明,不同品种授粉后能够显著提高Opal Star着果率,着果率从大到小依次为Unique> Coolidge> Mammoth> Triumph> OpalStar处理.授粉后Opal Star果实的单果质量、果形指数、种子数和可食率增加,果实内在品质得到改善.Unique和Triumph是Opal Star理想的授粉品种.

  10. 圆柱形蛋白石和反蛋白石结构光子晶体的制备及其光学性质*%Fabrication of cylindrical opals and inverse opals and their optical properties*

    Institute of Scientific and Technical Information of China (English)

    陈威; 王鸣†; 倪海彬

    2013-01-01

      研究了在圆柱曲面基底上自组装空心和实心的圆柱形蛋白石和反蛋白石结构光子晶体的方法。用垂直沉积法在不同曲率半径的毛细管内自组装了空心圆柱形聚苯乙烯(PS)蛋白石结构光子晶体薄膜和二氧化硅(SiO2)反蛋白石结构薄膜;用类重力沉积法制得实心圆柱形蛋白石和反蛋白石结构光子晶体,并讨论了这一生长方式中的状态变化过程及影响因素。用扫描电子显微镜对样品内部结构进行了表征,用光谱仪测试了光子晶体薄膜的反射光谱,结果表明:基底曲率半径和微球粒径的大小是影响空心蛋白石和反蛋白石薄膜质量的主要因素;微球大小是影响实心结构有序性的主要因素。%Hollow and solid cylindrical opals and inverse opals have been made by the self-assembly method in a capillary. The mechanism as well as the assembly process of monodispersed microspheres self-assembly in a capillary has been investigated. By the vertical self-assembly method, hollow cylindrical polystyrene opals and silica inverse opals of different radii have been made in capillaries;whereas cylindrical solid opals and inverse opals have been prepared under the interactions of gravity sedimentation, evaporation induced micro-flow, liquid surface tension and capillary tension. The growth process of producing solid photonic crystals in capillaries have been described and discussed. By scanning electron microscope, we characterize the internal structure of the samples and with spectrometer we test the reflection spectra of these films. Results show that the substrate curvature radius and microsphere size are the main factors that affect the quality of hollow cylindrical opal and inverse opal films while microsphere size has influence on the internal structure of solid cylindrical opals and inverse opals.

  11. Synthesis and Band Gap Control in Three-Dimensional Polystyrene Opal Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    LIU Ye; ZHENG Zhong-Yu; QIN Fei; ZHOU Fei; ZHOU Chang-Zhu; ZHANG Dao-Zhong; MENG Qing-Bo; LI Zhi-Yuan

    2008-01-01

    High-quality three-dimensional polystyrene opal photonic crystals are fabricated by vertical deposition method.The transmission properties with different incident angles and different composite refractive index contrasts are experimentally and theoretically studied. Good agreement between the experiment and theory is achieved. We find that with the increasing incident angle, the gap position shifts to the short wavelength (blue shift) and the gap becomes shallower; and with the increase of refractive index of the opal void materials and decrease the contrast of refractive index, the gap position shifts to the long wavelength (red shift). At the same time, we observe the swelling effects when the sample is immerged in the solutions with different refractive indices, which make the microsphere diameter in solution become larger than that in air. The understanding of band gap shift behaviour may be helpful in designing optical sensors and tunable photonic crystal ultrafast optical switches.

  12. Angular shaping of fluorescence from synthetic opal-based photonic crystal.

    Science.gov (United States)

    Boiko, Vitalii; Dovbeshko, Galyna; Dolgov, Leonid; Kiisk, Valter; Sildos, Ilmo; Loot, Ardi; Gorelik, Vladimir

    2015-01-01

    Spectral, angular, and temporal distributions of fluorescence as well as specular reflection were investigated for silica-based artificial opals. Periodic arrangement of nanosized silica globules in the opal causes a specific dip in the defect-related fluorescence spectra and a peak in the reflectance spectrum. The spectral position of the dip coincides with the photonic stop band. The latter is dependent on the size of silica globules and the angle of observation. The spectral shape and intensity of defect-related fluorescence can be controlled by variation of detection angle. Fluorescence intensity increases up to two times at the edges of the spectral dip. Partial photobleaching of fluorescence was observed. Photonic origin of the observed effects is discussed.

  13. Residual stress diffractometer KOWARI at the Australian research reactor OPAL: Status of the project

    Science.gov (United States)

    Brule, Alain; Kirstein, Oliver

    2006-11-01

    Neutron scattering using diffraction techniques is now recognized as the most precise and reliable method of mapping sub-surface residual stresses in materials or even components, which are not only of academic but also of industrial-economic relevance. The great potential of neutrons in the field of residual stresses was recognized by ANSTO and its external Beam Instrument Advisory Group for the new research reactor OPAL. The recommendation was to build the dedicated strain scanner KOWARI among the first suite of instruments available to users. We give an update on the overall project and present the current status of the diffractometer. It is anticipated that the instrument will be commissioned in mid 2006 and available to users at the end of the OPAL project.

  14. Millimeter Waveband Dielectric Properties of Nanocomposite Materials Based on Opal Matrices with Particles of Spinels

    Science.gov (United States)

    Rinkevich, A. B.; Perov, D. V.; Pakhomov, Ya A.; Samoylovich, M. I.; Kuznetsov, E. A.

    2016-09-01

    The dielectric properties of 3D nanocomposites based on opal matrices containing the particles of compounds with spinel structure have been studied. Microwave measurements have been carried out in the frequency range from 26 to 38 GHz. The frequency dependences of transmission and reflection coefficients are obtained. The values of the real and imaginary parts of complex dielectric permittivity have been retrieved. The X-ray phase analysis of the nanocomposites is performed and their structures are studied.

  15. Magnetic properties of nanocomposites based on opal matrices with embedded ferrite-spinel nanoparticles

    Science.gov (United States)

    Rinkevich, A. B.; Korolev, A. V.; Samoylovich, M. I.; Klescheva, S. M.; Perov, D. V.

    2016-02-01

    Magnetic properties of nanocomposites based on opal matrices with ferrite-spinel nanoparticles embedded have been investigated in temperature range from 2 to 300 K. The magnetization curves and hysteresis loops as well as the temperature dependence of magnetic moment and the temperature and frequency dependences of AC susceptibility have been measured. The results of magnetic measurements are compared to X-ray analysis and electron microscopy investigations.

  16. Diffraction anomalies in hybrid structures based on chalcogenide-coated opal photonic crystals

    CERN Document Server

    Voronov, M M; Yakovlev, S A; Kurdyukov, D A; Golubev, V G

    2014-01-01

    The results of spectroscopic studies of the diffraction anomalies (the so-called resonant Wood anomalies) in spatially-periodic hybrid structures based on halcogenide (GST225)-coated opal films of various thickness are presented. A theoretical analysis of spectral-angular dependencies of the Wood anomalies has been made by means of a phenomenological approach using the concept of the effective refractive index of waveguiding surface layer.

  17. The rheology and processing of “edge sheared” colloidal polymer opals

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Hon Sum; Mackley, Malcolm, E-mail: mrm5@cam.ac.uk; Butler, Simon [Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB2 3RA (United Kingdom); Baumberg, Jeremy; Snoswell, David; Finlayson, Chris; Zhao, Qibin [Cavendish Laboratory, NanoPhotonics Centre, University of Cambridge, Cambridge CB3 OHE (United Kingdom)

    2014-03-15

    This paper is concerned with the rheology and processing of solvent-free core shell “polymer opals” that consist of a soft outer shell grafted to hard colloidal polymer core particles. Strong iridescent colors can be produced by shearing the material in a certain way that causes the initially disordered spheres to rearrange into ordered crystalline structures and produce colors by diffraction and interference of multiple light scattering, similar to gemstone opals. The basic linear viscoelastic rheology of a polymer opal sample was determined as a function of temperature, and the material was found to be highly viscoelastic at all tested temperatures. A Cambridge multipass rheometer was specifically modified in order to make controlled mechanical measurements of initially disordered polymer opal tapes that were sandwiched between protective polyethylene terephthalate sheets. Axial extension, simple shear, and a novel “edge shearing” geometry were all evaluated, and multiple successive experiments of the edge shearing test were carried out at different temperatures. The optical development of colloidal ordering, measured as optical opalescence, was quantified by spectroscopy using visible backscattered light. The development of opalescence was found to be sensitive to the geometry of deformation and a number of process variables suggesting a complex interaction of parameters that caused the opalescence. In order to identify aspects of the deformation mechanism of the edge shearing experiment, a separate series of in situ optical experiments were carried out and this helped indicate the extent of simple shear generated with each edge shear deformation. The results show that strong ordering can be induced by successive edge shearing deformation. The results are relevant to polymer opal rheology, processing, and mechanisms relating to ordering within complex viscoelastic fluids.

  18. Characterization of the OPAL LiDAR under controlled obscurant conditions

    Science.gov (United States)

    Cao, Xiaoying; Church, Philip; Matheson, Justin

    2016-05-01

    Neptec Technologies' OPAL-120 3D LiDAR is optimized for obscurant penetration. The OPAL-120 uses a scanning mechanism based on the Risley prism pair. The scan patterns are created by rotating two prisms under independent motor control. The geometry and material properties of the prisms define the conical field-of-view of the sensor, which can be built to between 60 to 120 degrees. The OPAL-120 was recently evaluated using a controlled obscurant chamber capable of generating clouds of obscurants over a depth of 22m. Obscurants used in this investigation include: Arizona road dust, water fog, and fog-oil. The obscurant cloud optical densities were monitored with a transmissometer. Optical depths values ranged from an upper value of 6 and progressively decreased to 0. Targets were positioned at the back of the obscurant chamber at a distance of 60m from the LiDAR. The targets are made of a foreground array of equally spaced painted wood stripes in front of a solid background. Reflectivity contrasts were achieved with foreground/background combinations of white/white, white/black and black/white. Data analysis will be presented on the effect of optical densities on range and cross-range resolution, and accuracy. The analysis includes the combinations of all obscurant types and target reflectivity contrasts.

  19. Inverse gold photonic crystals and conjugated polymer coated opals for functional materials

    Energy Technology Data Exchange (ETDEWEB)

    Landon, P.B.; Gutierrez, Jose; Ferraris, John P.; Martinez, I.L.; Giridharagopal, Rajiv; Wu, Y.-C.; Lee, Sergey; Parikh, Kunjal; Gillespie, Jessica; Ussery, Geoffrey; Karimi, Behzad; Baughman, Ray; Zakhidov, Anvar; Glosser, R

    2003-10-01

    Inverse gold photonic crystals templated from synthetic opals with a face centered cubic (FCC) crystal lattice were constructed by heat converting gold chloride to metallic gold. Tetrahedral formations constructed of alternating large and small octahedrons oriented in the zinc sulfide structure were created by controlling the infiltration of gold chloride. Silica spheres were coated with polyanilinesulfonic acid, polypyrrole, poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and 5 nm colloidal gold. Ordinary yeast cells were coated with polyanilinesulfonic acid, polypyrrole and 5 nm colloidal gold. Spheres coated with MEH-PPV were dispersed in H{sub 2}O and coated with polyelectrolytes which recharged and sterically stabilized the colloidal surfaces. The recharged spheres self-assembled by sedimentation with a FCC crystalline lattice possessing 500 {mu}m wide and 1 mm long crystallites. Silica spheres with diameters as large as 1500 {mu}m were self-assembled along the [1 0 0] direction of the FCC crystal lattice. Opals infiltrated with gold and opals constructed from polymer coated spheres were co-infiltrated with polypropylene yielding inverse polypropylene composite photonic crystals.

  20. Ceria based inverse opals for thermochemical fuel production: Quantification and prediction of high temperature behavior

    Science.gov (United States)

    Casillas, Danielle Courtney

    Solar energy has the potential to supply more than enough energy to meet humanity's energy demands. Here, a method for thermochemical solar energy storage through fuel production is presented. A porous non-stoichiometric oxide, ceria, undergoes partial thermal reduction and oxidation with concentrated solar energy as a heat source, and water as an oxidant. The resulting yields for hydrogen fuel and oxygen are produced in two discrete steps, while the starting material maintains its original phase. Ordered porosity has been shown superior to random porosity for thermochemical fuel production applications, but stability limits for these structures are currently undefined. Ceria-based inverse opals are currently being investigated to assess the architectural influence on thermochemical hydrogen production. Low tortuosity and continuous interconnected pore network allow for facile gas transport and improved reaction kinetics. Ceria-based ordered materials have recently been shown to increase maximum hydrogen production over non-ordered porous ceria. Thermal stability of ordered porosity was quantified using quantitative image analysis. Fourier analysis was applied to SEM images of the material. The algorithm results in an order parameter gamma that describes the degree of long range order maintained by these structures, where gamma>4 signifies ordered porosity. According to this metric, a minimum zirconium content of 20 atomic percent (at%) is necessary for these architectures to survive aggressive annealing up to 1000°C. Zirconium substituted ceria (ZSC) with Zr loadings in excess of 20at% developed undesired tetragonal phases. Through gamma, we were able to find a balance between the benefit of zirconium additions on structural stability and its negative impact on phase. This work demonstrates the stability of seemingly delicate architectures, and the operational limit for ceria based inverse opals to be 1000°C for 1microm pore size. Inverse opals having sub

  1. ZnS-opal与反opal结构ZnS光子晶体的组装%Fabrication and characterization of ZnS-opal and inverse opal ZnS photonic crystals

    Institute of Scientific and Technical Information of China (English)

    段涛; 彭同江; 唐永建

    2009-01-01

    以单分散SiO2微球为基元,在75%~80%湿度、30~45℃恒温密闭烘箱中垂直快速组装opal模板;以Zn(NO3)2(0.035mol/L)、TAA乙醇溶液(0.05mol/L)为前体,通过溶剂热法充填形成ZnS-opal复合光子晶体;ZnS-opal复合光子晶体在2%~5%的HF溶液中浸泡4~5 h后卸载模板,制得反opal结构ZnS基光子晶体;采用XRD、SEM、UV-Vis测试手段对反opal结构ZnS基光子晶体形貌、物相和光学性能进行了表征.结果表明:溶剂热法多次充填可使ZnS纳米晶在模板密堆积形成的空隙中均匀成核;经过酸处理的ZnS-opal中SiO2微球溶解、坍塌,形成蜂窝状三维有序介孔和反opal结构ZnS基光子晶体;相同粒径SiO2微球组装的opal模板、ZnS-opal以及反opal结构ZnS光子晶体均表现出光子带隙特性,但反opal结构ZnS光子晶体带隙位置相比前两者发生了蓝移.%Opal templates were rapidly assembled from monodisperse SiO2 microspheres as building blocks by vertical sedimentation in an airtight oven at 30-45 ℃ and in a certain humidity. With a precursor composed of 0.035mol/L Zn (NO3)2 and 0.05mol/L TAA ethanol solution, ZnS photortic crystals with opal structure were prepared by solvothermal synthesis method repeatly. ZnS photonic crystals with inverse opal structure were obtained by removing the opal template after immersing in 2%-5% HF acid for 4-5 h. The morphology, component and optical properties of the synthetic samples were tested and compared. Results of XRD, SEM, and UV-Vis indicated that ZnS nanocrystals can grow in and fill in the void of opal template, and SiO2 microspheres of templates are dissolved so as to form some three dimensional ordered porous structure and to form the inverse opal ZnS photonic crystals. Compared with opal templates, ZnS-opal and inverse opal ZnS photonic crystals assembled with SiO2 spheres in the same diameter show good optical properties and exhibited photonic band gap. The photonic band gap position of inverse

  2. Ages and Origins of Calcite and Opal in the Exploratory Studies Facility Tunnel, Yucca Mountain, Nevada

    Science.gov (United States)

    Paces, James B.; Neymark, Leonid A.; Marshall, Brian D.; Whelan, Joseph F.; Peterman, Zell E.

    2001-01-01

    Deposits of calcite and opal are present as coatings on open fractures and lithophysal cavities in unsaturated-zone tuffs at Yucca Mountain, Nevada, site of a potential high-level radioactive waste repository. Outermost layers of calcite and opal have radiocarbon ages of 16,000 to 44,000 years before present and thorium-230/uranium ages of 28,000 to more than 500,000 years before present. These ages are young relative to the 13-million-year age of the host rocks. Multiple subsamples from the same outer layer typically show a range of ages with youngest ages from the thinnest subsamples. Initial uranium-234/uranium-238 activity ratios between 1 and 9.5 show a distinct negative correlation with thorium-230/uranium age and are greater than 4 for all but one sample younger than 100,000 years before present. These data, along with micrometer-scale layering and distinctive crystal morphologies, are interpreted to indicate that deposits formed very slowly from water films migrating through open cavities. Exchanges of carbon dioxide and water vapor probably took place between downward-migrating liquids and upward-migrating gases at low rates, resulting in oversaturation of mineral constituents at crystal extremities and more or less continuous deposition of very thin layers. Therefore, subsamples represent mixtures of older and younger layers on a scale finer than sampling techniques can resolve. Slow, long-term rates of deposition (less than about 5 millimeters of mineral per million years) are inferred from subsamples of outermost calcite and opal. These growth rates are similar to those calculated assuming that total coating thicknesses of 10 to 40 millimeters accumulated over 12 million years. Calcite has a wide range of delta carbon-13 values from about -8.2 to 8.5 per mil and delta oxygen-18 values from about 10 to 21 per mil. Systematic microsampling across individual mineral coatings indicates basal (older) calcite tends to have the largest delta carbon-13 values

  3. Thermoresponsive Polymers and Inverse Opal Hydrogels for the Detection of Diols.

    Science.gov (United States)

    Couturier, Jean-Philippe; Wischerhoff, Erik; Bernin, Robert; Hettrich, Cornelia; Koetz, Joachim; Sütterlin, Martin; Tiersch, Brigitte; Laschewsky, André

    2016-05-01

    Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers' cloud point, or the induced changes of the hydrogels' swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.

  4. Calcite/opal deposits at Yucca Mountain, Nevada: Pedogenic or hypogene?

    Energy Technology Data Exchange (ETDEWEB)

    Hill, C.A.; Schluter, C.M.; Harmon, R.S. [and others

    1994-01-01

    This study is part of the research program of the Yucca Mountain Project intended to provide the State of Nevada with a detailed assessment of the geology and geochemistry of Yucca Mountain and adjacent regions. The purpose of this paper is to consider all of the geological and geochemical data available for the calcite/opal deposits at Yucca Mountain and to ascertain whether this data favors a pedogenic or hyogene origin for these deposits. Far from being of esoteric concern, this subject is of paramount importance to the debate which rages around the suitability of Yucca Mountain as a high-level radioactive waste repository site. It is also the purpose of this paper to serve as a foundation for a lengthy feature article to be submitted for publication in 1994. In addition, a stand has been taken by the National Research Council of the National Academy of Sciences against the upwelling-water model (a vote of 17 to 0 against), and this same panel report has concluded that {open_quotes}there is no compelling evidence for the repetitive flooding of the environment by expulsion of groundwater{close_quotes} and that {open_quotes}instead, the evidence strongly supports the idea that the near-surface mineral deposits resulted from percolating rainwater, which carried soil minerals down into rock fractures{close_quotes}. Based on such information the Department of Energy has stated that it {open_quotes}finds no basis to continue to study the origin of these specific deposits{close_quotes}. This study, based upon many different independent lines of evidence, reaches the opposite conclusion and instead favors a hypogene spring-travertine origin for the controversial calcite/opal deposits at Yucca Mountain. This study recognizes a pedogenic carbonate component at Yucca Mountain, but argues that this component is distinct from, and sometimes intermixed with, the calcite/opal deposits.

  5. Stress factors in the aftermath of Hurricanes Erin and Opal: data from small business owners.

    Science.gov (United States)

    Piotrowski, C; Armstrong, T; Stopp, H

    1997-06-01

    Hurricanes Erin and Opal struck the same coastal region in the Northwest Florida Panhandle in late summer of 1995. The study examined the stressors that most affected small businesses in the region in the aftermath of the storms. Power outages, telephone disruptions, employees' availability, debris removal, and lack of customers were the major problem areas reported by business owners (N = 57 of 500 potential respondents). The results indicate that most of the stress factors were transitory and the findings are discussed in light of Murphy's 1985 conceptual model of disaster research.

  6. Fabrication and Photo-Detecting Performance of 2D ZnO Inverse Opal Films

    Directory of Open Access Journals (Sweden)

    Xin Lin

    2016-09-01

    Full Text Available Two-dimensional (2D ZnO inverse opal (IO films were fabricated by co-assembly of sacrificed polystyrene (PS microspheres and citric acid/zinc acetate (CA/ZA aqueous solution at an oil–water interface followed by calcination. Their morphologies could be controlled by the surface property of polymer templates and CA/ZA molar ratio. Moreover, photo-detecting devices based on such films were constructed, which showed high photocurrent (up to 4.6 μA, excellent spectral selectivity, and reversible response to optical switch.

  7. Magnetic properties of 3D nanocomposites consisting of an opal matrix with embedded spinel ferrite particles

    Science.gov (United States)

    Rinkevich, A. B.; Korolev, A. V.; Samoylovich, M. I.; Kleshcheva, S. M.; Perov, D. V.

    2016-02-01

    The magnetic properties of 3D nanocomposites representing Mn-Zn, Ni-Zn, Co-Zn, La-Co-Zn, and Nd-Co-Zn spinel ferrite particles embedded in the interspherical spaces of opal matrices are studied. Experimental data are obtained in the temperature interval 2-300 K by measuring the magnetization at a static magnetic field strength of up to 50 kOe and the ac magnetic susceptibility at an alternating magnetic field amplitude of 4 kOe and a frequency of 80 Hz.

  8. Sputtered-silica defect layer in artificial opals: tunability of highly transmitted and reflected optical modes

    CERN Document Server

    Hong, Phan Ngoc; Coolen, Laurent; Maître, Agnès; Schwob, Catherine

    2013-01-01

    We propose an original and efficient method to engineer a defect between two well-ordered silica opals by sputtering silica on the top of the first one. As the amount of sputtered silica can be well controlled, it is also the case for the thickness of the layer and consequently for the spectral position of the defect mode. The optical response of these sandwich structures is studied in terms of specular reflection and transmission spectroscopy. Tunable highly transmitted and reflected optical modes are evidenced. The very good agreement between the experimental results and the simulations, run without fitting parameters, demonstrates the almost perfect order of the synthesized structures.

  9. Radiation monitoring and beam dump system of the OPAL silicon microvertex detector

    Science.gov (United States)

    Biebel, O.; Braibant, S.; de Jong, S. J.; Hammarström, R.; Hilgers, R.; Honma, A. K.; Jovanovic, P.; Lauber, J. A.; Neal, H. A.

    1998-02-01

    The radiation monitoring and beam dump system of the OPAL silicon microvertex detector is described. This system was designed and implemented to measure the radiation dose over time scales varying from a millisecond to a year, and to induce a fast beam dump if the radiation exceeds a given threshold in dose and in dose rate within a very small time interval. The system uses reverse-biased silicon diodes as sensitive elements and good stability is achieved by AC coupling of the amplifiers to the sensors.

  10. The Periodic Safety Review of ANSTO's OPAL Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Summerfield, Mark [ANSTO, Sydney (Australia)

    2013-07-01

    This paper describes the process by which the first Periodic Safety Review (PSR) of ANSTO's OPAL reactor was performed and documented. Emphasis is given to the methodology adopted and the practical means of actually doing a PSR with the aim of providing advice and guidance to other research reactor operators intending (or required) to perform a PSR. A summary of the results is also provided, including an overview of the recommendations. Feedback received from the Australian Nuclear Regulator ARPANSA and the subsequent preparation of a PSR Supplement is discussed.

  11. Fabrication of Au- and Ag–SiO{sub 2} inverse opals having both localized surface plasmon resonance and Bragg diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Erola, Markus O.A.; Philip, Anish; Ahmed, Tanzir; Suvanto, Sari; Pakkanen, Tuula T., E-mail: Tuula.Pakkanen@uef.fi

    2015-10-15

    The inverse opal films of SiO{sub 2} containing metal nanoparticles can have both the localized surface plasmon resonance (LSPR) of metal nanoparticles and the Bragg diffraction of inverse opal crystals of SiO{sub 2}, which are very useful properties for applications, such as tunable photonic structures, catalysts and sensors. However, effective processes for fabrication of these films from colloidal particles have rarely been reported. In our study, two methods for preparation of inverse opal films of SiO{sub 2} with three different crystal sizes and containing gold or silver nanoparticles (NPs) via self-assembly using electrostatic interactions and capillary forces are reported. The Bragg diffraction of inverse opal films of SiO{sub 2} in the presence and absence of the template was measured and predicted on the basis of with UV–vis spectroscopy and scanning electron microscopy. The preparation methods used provided good-quality inverse opal SiO{sub 2} films containing highly dispersed, plasmonic AuNPs or AgNPs and having both Bragg diffractions and LSPRs. - Graphical abstract: For syntheses of SiO{sub 2} inverse opals containing Au/Ag nanoparticles two approaches and three template sizes were employed. Self-assembly of template molecules and metal nanoparticles occurred using electrostatic interactions and capillary forces. Both the Bragg diffraction of the photonic crystal and the localized surface plasmon resonance of Au/Ag nanoparticles were detected. - Highlights: • Fabrication methods of silica inverse opals containing metal nanoparticles studied. • Three template sizes used to produce SiO{sub 2} inverse opals with Au/Ag nanoparticles. • PS templates with Au nanoparticles adsorbed used in formation of inverse opals. • Ag particles infiltrated in inverse opals with capillary and electrostatic forces. • Bragg diffractions of IOs and surface plasmon resonances of nanoparticles observed.

  12. Conductive framework of inverse opal structure for sulfur cathode in lithium-sulfur batteries.

    Science.gov (United States)

    Jin, Lu; Huang, Xiaopeng; Zeng, Guobo; Wu, Hua; Morbidelli, Massimo

    2016-09-07

    As a promising cathode inheritor for lithium-ion batteries, the sulfur cathode exhibits very high theoretical volumetric capacity and energy density. In its practical applications, one has to solve the insulating properties of sulfur and the shuttle effect that deteriorates cycling stability. The state-of-the-art approaches are to confine sulfur in a conductive matrix. In this work, we utilize monodisperse polystyrene nanoparticles as sacrificial templates to build polypyrrole (PPy) framework of an inverse opal structure to accommodate (encapsulate) sulfur through a combined in situ polymerization and melting infiltration approach. In the design, the interconnected conductive PPy provides open channels for sulfur infiltration, improves electrical and ionic conductivity of the embedded sulfur, and reduces polysulfide dissolution in the electrolyte through physical and chemical adsorption. The flexibility of PPy and partial filling of the inverse opal structure endure possible expansion and deformation during long-term cycling. It is found that the long cycling stability of the cells using the prepared material as the cathode can be substantially improved. The result demonstrates the possibility of constructing a pure conductive polymer framework to accommodate insulate sulfur in ion battery applications.

  13. Preparation and structural stability of ordered nanocomposites: opal matrix - lead titanates

    Science.gov (United States)

    Samoylovich, M. I.; Mkrtchyan, A. R.; Belyanin, A. F.; Bagdasaryan, S. A.; Kiziridi, A. A.

    2016-06-01

    The conditions for the formation of nanocomposites based on the basis of lattice packings of SiO2 nanospheres (opal matrices) with included crystallites of lead titanates (PbTiO3 and PbTi3O7) in interspherical nanospacing are considered. For the formation of nanocomposites are used sample opal matrices with dimensions of single-domain regions ≥0,1 mm.3 The diameter of SiO2 nanospheres was ∼260 nm. Obtained nanocomposites volume >2 cm3 in filling >20% of interspherical nanospacing PbTiO3, PbTi3O7 crystallites were size of 16-36 nm. Using X-ray diffraction and Raman spectroscopy are studied composition and structural stability when heated nanocomposites to 550°C, which allowed the identification of a local phase transition with change of the space group. The dependence of the composition of synthesized materials on the conditions of their preparation is submitted.

  14. αs analyses from hadronic tau decays with OPAL and ALEPH data

    Science.gov (United States)

    Boito, Diogo; Golterman, Maarten; Maltman, Kim; Peris, Santiago

    2016-07-01

    Recently, we extracted the strong coupling, αs(mτ2), from the revised ALEPH data for non-strange hadronic tau decays. Our analysis is based on a method previously used for the determination of the strong coupling from OPAL data. In our strategy, we employ different moments of the spectral functions both with and without pinching, including duality violations, in order to obtain fully self-consistent analyses that do not rely on untested assumptions (such as the smallness of higher dimension contributions in the operation product expansion (OPE)). Here we discuss the αs values obtained from the ALEPH and the OPAL data, the robustness of the analysis, as well as non-perturbative contributions from DVs and the OPE. We show that, although the αs determination is sound, non-perturbative effects limit the accuracy with which one can extract the strong coupling from tau decay data. Finally, we discuss the compatibility of the data sets and the possibility of a combined analysis.

  15. Manifestation of intrinsic defects in optical properties of self-organized opal photonic crystals

    Science.gov (United States)

    Vlasov; Astratov; Baryshev; Kaplyanskii; Karimov; Limonov

    2000-05-01

    Self-organized synthetic opals possessing a face centered cubic (fcc) lattice are promising for fabrication of a three-dimensional photonic crystal with a full photonic band gap in the visible. The fundamental limiting factor of this method is the large concentration of lattice defects and, especially, planar stacking faults, which are intrinsic to self-assembling growth of colloidal crystal. We have studied the influence of various types of defects on photonic band structure of synthetic opals by means of optical transmission, reflection and diffraction along different crystallographic directions. We found that in carefully chosen samples the stacking probability alpha can be as high as 0.8-0.9 revealing the strong preference of fcc packing sequence over the hexagonal close-packed (hcp). It is shown that scattering on plane stacking faults located perpendicular to the direction of growth results in a strong anisotropy of diffraction pattern as well as in appearance of a pronounced doublet structure in transmission and reflection spectra taken from the directions other than the direction of growth. This doublet is a direct manifestation of the coexistence of two crystallographic phases--pure fcc and strongly faulted. As a result the inhomogeneously broadened stop-bands overlap over a considerable amount of phase space. The latter, however, does not mean the depletion of the photonic density of states since large disordering results in filling of the partial gaps with both localized and extended states.

  16. Conductive framework of inverse opal structure for sulfur cathode in lithium-sulfur batteries

    Science.gov (United States)

    Jin, Lu; Huang, Xiaopeng; Zeng, Guobo; Wu, Hua; Morbidelli, Massimo

    2016-09-01

    As a promising cathode inheritor for lithium-ion batteries, the sulfur cathode exhibits very high theoretical volumetric capacity and energy density. In its practical applications, one has to solve the insulating properties of sulfur and the shuttle effect that deteriorates cycling stability. The state-of-the-art approaches are to confine sulfur in a conductive matrix. In this work, we utilize monodisperse polystyrene nanoparticles as sacrificial templates to build polypyrrole (PPy) framework of an inverse opal structure to accommodate (encapsulate) sulfur through a combined in situ polymerization and melting infiltration approach. In the design, the interconnected conductive PPy provides open channels for sulfur infiltration, improves electrical and ionic conductivity of the embedded sulfur, and reduces polysulfide dissolution in the electrolyte through physical and chemical adsorption. The flexibility of PPy and partial filling of the inverse opal structure endure possible expansion and deformation during long-term cycling. It is found that the long cycling stability of the cells using the prepared material as the cathode can be substantially improved. The result demonstrates the possibility of constructing a pure conductive polymer framework to accommodate insulate sulfur in ion battery applications.

  17. A novel opal closest-packing photonic crystal for naked-eye glucose detection.

    Science.gov (United States)

    Hong, Xiaodi; Peng, Yuan; Bai, Jialei; Ning, Baoan; Liu, Yuanyuan; Zhou, Zhijiang; Gao, Zhixian

    2014-04-09

    A novel opal closest-packing (OCP) photonic crystal (PC) is successfully prepared for naked-eye glucose detection. This PC is fabricated via a vertical convective self-assembly method with a new type of monodisperse microsphere polymerized by co-monomers, namely, methyl methacrylate (MMA), N-isopropylacrylamide (NIPA), and 3-acrylamidophenylboronic acid (AAPBA). The OCP PC has high stability and periodically-ordered structure, showing the desired structural color. The proposed PC material displays a red shift and reduced reflection intensity when detecting glucose molecules. The red-shift wavelength reaches 75 nm, which clearly changes the structural color from brilliant blue to emerald green. This visually distinguishable color change facilitates the detection of the glucose concentrations from 3 to 20 mm, which demonstrates the potential of the opal PC material for naked-eye detection. Thus, the novel PMMA–NIPA–AAPBA OCP PC is a simply prepared and sensitive material, which shows promising use in the diagnosis of diabetes mellitus and in real-time monitoring of diabetes. Different types of appropriated recognition groups are expected to be introduced into the 3D OCP PC to form new functional materials or chemical sensors, which will extensively broaden the PC material application.

  18. Inverse opal hydrogel-collagen composite scaffolds as a supportive microenvironment for immune cell migration.

    Science.gov (United States)

    Stachowiak, Agnieszka N; Irvine, Darrell J

    2008-06-01

    Immunotherapies harness the inherent potential of the body to destroy foreign or infected cells, and are currently being investigated as treatments for cancer. One way to boost native immune responses might be to engineer ectopic lymphoid tissue, providing a supportive microenvironment for immune cell priming, and/or bringing together immune cells at a desired location (e.g., solid tumor sites). Here we describe the development and in vitro testing of composite macroporous poly(ethylene glycol) (PEG) hydrogel scaffolds infused with collagen as a tissue engineering platform for immunotherapy. The PEG hydrogel with ordered, interconnected pores provided mechanical stability and the potential to depot supporting cytokines/chemokines, while an infused collagen matrix supported intra-scaffold migration of loaded T cells and dendritic cells. Rapid, nearly unconstrained T cell migration through scaffolds was achieved by using inverse opal supporting structures with 80 microm macropores. In addition, we demonstrated that the lymphoid tissue chemokine CCL21 could be bound to the inverse opal gel walls of these scaffolds, to provide motility-inducing cues for T cells within these structures. This hybrid scaffold approach combines the strengths of the synthetic and biopolymer hydrogels used in a highly synergistic fashion, allowing each material to compensate for limiting properties of its partner. Copyright 2007 Wiley Periodicals, Inc.

  19. $\\alpha_s$ analyses from hadronic tau decays with OPAL and ALEPH data

    CERN Document Server

    Boito, Diogo; Maltman, Kim; Peris, Santiago

    2016-01-01

    Recently, we extracted the strong coupling, $\\alpha_s(m_\\tau^2)$, from the revised ALEPH data for non-strange hadronic tau decays. Our analysis is based on a method previously used for the determination of the strong coupling from OPAL data. In our strategy, we employ different moments of the spectral functions both with and without pinching, including Duality Violations, in order to obtain fully self-consistent analyses that do not rely on untested assumptions (such as the smallness of higher dimension contributions in the OPE). Here we discuss the $\\alpha_s$ values obtained from the ALEPH and the OPAL data, the robustness of the analysis, as well as non-perturbative contributions from DVs and the OPE. We show that, although the $\\alpha_s$ determination is sound, non-perturbative effects limit the accuracy with which one can extract the strong coupling from tau decay data. Finally, we discuss the compatibility of the data sets and the possibility of a combined analysis.

  20. Conductive framework of inverse opal structure for sulfur cathode in lithium-sulfur batteries

    Science.gov (United States)

    Jin, Lu; Huang, Xiaopeng; Zeng, Guobo; Wu, Hua; Morbidelli, Massimo

    2016-01-01

    As a promising cathode inheritor for lithium-ion batteries, the sulfur cathode exhibits very high theoretical volumetric capacity and energy density. In its practical applications, one has to solve the insulating properties of sulfur and the shuttle effect that deteriorates cycling stability. The state-of-the-art approaches are to confine sulfur in a conductive matrix. In this work, we utilize monodisperse polystyrene nanoparticles as sacrificial templates to build polypyrrole (PPy) framework of an inverse opal structure to accommodate (encapsulate) sulfur through a combined in situ polymerization and melting infiltration approach. In the design, the interconnected conductive PPy provides open channels for sulfur infiltration, improves electrical and ionic conductivity of the embedded sulfur, and reduces polysulfide dissolution in the electrolyte through physical and chemical adsorption. The flexibility of PPy and partial filling of the inverse opal structure endure possible expansion and deformation during long-term cycling. It is found that the long cycling stability of the cells using the prepared material as the cathode can be substantially improved. The result demonstrates the possibility of constructing a pure conductive polymer framework to accommodate insulate sulfur in ion battery applications. PMID:27600885

  1. Computational Fluid Dynamics (CFD) Analysis Of Optical Payload For Lasercomm Science (OPALS) sealed enclosure module

    Science.gov (United States)

    Anderson, Kevin R.; Zayas, Daniel; Turner, Daniel

    2012-01-01

    Computational Fluid Dynamics (CFD) using the commercial CFD package CFDesign has been performed at NASA Jet Propulsion Laboratory (JPL) California Institute of Technology (Caltech) in support of the Phaeton Early Career Hire Program's Optical Payload for Lasercomm Science (OPALS) mission. The OPALS project is one which involves an International Space Station payload that will be using forced convection cooling in a hermetically sealed enclosure at 1 atm of air to cool "off-the-shelf" vendor electronics. The CFD analysis was used to characterize the thermal and fluid flow environment within a complicated labyrinth of electronics boards, fans, instrumentation, harnessing, ductwork and heat exchanger fins. The paradigm of iteratively using CAD/CAE tools and CFD was followed in order to determine the optimum flow geometry and heat sink configuration to yield operational convective film coefficients and temperature survivability limits for the electronics payload. Results from this current CFD analysis and correlation of the CFD model against thermal test data will be presented. Lessons learned and coupled thermal / flow modeling strategies will be shared in this paper.

  2. Past Warmer Climate Periods at the Antarctic Margin Detected From Proxies and Measurements of Biogenic Opal in the AND-1B Core: The XRF Spectral Silver (Ag) Peak Used as a new Tool for Biogenic Opal Quantification.

    Science.gov (United States)

    Kuhn, G.; Helling, D.; von Eynatten, H.; Niessen, F.; Magens, D.

    2008-12-01

    Quantification of biogenic opal in marine sediments is a time consuming job, but the results could indicate periods of higher bioproductivity and warmer conditions than today at the Antarctic margin. Within the international Antarctic Geological Drilling Program (ANDRILL), core AND-1B was drilled and recovered a 1285 m sequence from a flexural moat basin filled with glacimarine, terrigenous, volcanic and biogenic sediments below the McMurdo Ice Shelf. Our main goal is to study the variability and the stability of the Ross Ice Shelf from Miocene to Recent. The melting and collapse of large Antarctic ice shelves may cause a significant sea level rise because of accelerated inland ice glacier surges into the ocean. Biogenic opal content in sediments can be deduced indirectly from grain density measurements on single samples, or faster and more continuous by gamma ray attenuation measurements on the core, with subsequent wet bulk and grain density calculations. Spectral colour reflectance (b* value) measurements on the split core surface can also be a fast tool for opal content quantification. Of course, they all have disadvantages in comparison to direct measurement on samples using X-ray diffraction or geochemical leaching methods. Some major and minor chemical elements were measured directly on split core surfaces with a non- destructive X-Ray Fluorescence Core Scanner method (XRF-CS, Avaatech) in the field. Quantitative geochemical analyses like determination of total inorganic and organic carbon (TOC), biogenic opal as well as major and minor elements were done on core samples. We found a strong positive correlation between the counts per second of the XRF-CS Ag peak area and the biogenic opal content of the samples (r=0.81) not only in the AND-1B core but in others as well from the Antarctic margin. In literature, it is noted that diatoms could accumulate Ag in sediments, so at first we were pleased to find this Ag enrichment with our tool. But further

  3. Production, oxygen respiration rates, and sinking velocity of copepod fecal pellets: Direct measurements of ballasting by opal and calcite

    DEFF Research Database (Denmark)

    Ploug, H.; Iversen, M.H.; Koski, Marja;

    2008-01-01

    sp., T. weissflogii, and E. huxleyi, respectively. The average carbon-specific respiration rate was 0.15 d(-1) independent on diet (range: 0.08-0.21 d(-1)). Because of ballasting of opal and calcite, sinking velocities were significantly higher for pellets produced on T. weissflogii (322 +/- 169 m d...

  4. Periodic order and defects in Ni-based inverse opal-like crystals on the mesoscopic and atomic scale

    NARCIS (Netherlands)

    Chumakova, A. V.; Valkovskiy, G. A.; Mistonov, A. A.; Dyadkin, V. A.; Grigoryeva, N. A.; Sapoletova, N. A.; Napolskii, K. S.; Eliseev, A. A.; Petukhov, Andrei V.; Grigoriev, S. V.

    2014-01-01

    The structure of inverse opal crystals based on nickel was probed on the mesoscopic and atomic levels by a set of complementary techniques such as scanning electron microscopy and synchrotron microradian and wide-angle diffraction. The microradian diffraction revealed the mesoscopic-scale face-cente

  5. Opal phytolith and isotopic studies of "Restinga" communities of Maricá, Brazil, as a modern reference for paleobiogeoclimatic reconstruction

    Directory of Open Access Journals (Sweden)

    Cátia Pereira dos Santos

    2015-09-01

    Full Text Available AbstractThe Maricá restinga, located in the eastern part of the Rio de Janeiro State (Brazil, corresponds to one of the few remaining preserved areas of the state's coastal plain. This paper reports on a study of the Maricá restinga plant communities and also presents an identification of the main plant species present in each community, with the objective of establishing reference collections, by the methods of the proxies opal phytoliths and stable carbon isotopes, for paleoenvironmental reconstructions of this coastal area during the Quaternary. Six plant communities, distributed perpendicularly to the coast line over sandy barriers, lagoonal plain, lagoon margin and weathered basement were identified: halophile-psamophile, scrub, herbaceous swamp, slack, shrubby vegetation and dry forest. In general, the plant species analyzed in each community presented low productivity of opal phytoliths, as only the Poaceae, Cyperaceae and Arecaceae families produce a great amount and diversity of morphotypes of opal phytoliths. The results of the analysis of stable carbon isotopes in sediments indicated a predominance of C3 or a mixture of C3 and C4 plants, presenting a close correlation with the results found in plants collected in each community. In conclusion, it was verified that the carbon isotope analysis associated with that of the opal phytoliths are good proxies for the reconstruction of vegetation in the study area.

  6. Multifunctional Inverse Opal-Like TiO2 Electron Transport Layer for Efficient Hybrid Perovskite Solar Cells.

    Science.gov (United States)

    Chen, Xiao; Yang, Shuang; Zheng, Yi Chu; Chen, Ying; Hou, Yu; Yang, Xiao Hua; Yang, Hua Gui

    2015-09-01

    A novel multifunctional inverse opal-like TiO2 electron transport layer (IOT-ETL) is designed to replace the traditional compact layer and mesoporous scaffold layer in perovskite solar cells (PSCs). Improved light harvesting efficiency and charge transporting performance in IOT-ETL based PSCs yield high power conversion efficiency of 13.11%.

  7. Regional variations in the fluxes of foraminifera carbonate, coccolithophorid carbonate and biogenic opal in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; Gaye, B.

    NE Fig. 10. Pie diagrams showing the relative fluxes of diatom-opal, coccolithoph material during the southwest (SW) and northeast (NE) monsoon period. CBBT EIOT WAST SW NE SW NE argued that in the presence of iron, derived from aeolian dust...

  8. Solving geological and historical puzzles with advanced gemologic techniques: The Franco Dávila (1772 precious opal case

    Directory of Open Access Journals (Sweden)

    J. García-Guinea

    2016-11-01

    Full Text Available The large precious opal weighting 33 grams fitted in a silver jewel and exposed to visitors at the Museo Nacional de Ciencias Naturales (MNCN is well documented in: (i its own mounting (1772, (ii at the 775 document of the Archive of the MNCN and (iii the 395 specimen described in the of Pedro Franco Dávila catalogue. The X-ray diffractogram (XRD performed onto the opal block is very similar to other opals of volcanic origin containing varied amounts of cristobalite, tridymite and amorphous silica. The Raman spectrum shows a band peaked at 242, 343 and 416 cm-1 associated with O-Si-O stretching groups; other spectral band peaked at 780 and 819 cm-1 corresponding to vibration of symmetrical O-Si-O rings of 3 and 4 link members, plus other minor bands. The Raman spectrum is also very similar to those observed in Mexican opals of volcanic origin containing an spectral band of stretching nodes v1 (OH at 3233, 3393, 3511, 3628 cm-1 related to OH groups with hydrogen bonds of isolated silanol groups. The interferometric confocal dual microscope 3D (MCI3D, which is a nondestructive facility of high resolution and LED technology reveals the geometry of graver tools on the silver jewel and the computed tomography X-ray highlights the opal cutting as a squared princess type and silver chloride infillings of a crack probably caused by a shock on a corner. Under the scanning electron microscope we observed barite, sealed veins of silica rich in Mn and opal with high contents of Al and K which, along with the historical data, the piece can be attributed to the historical site of opals hosted in Slovakia andesite rocks, this data explains the optical light behavior in the cabochon. The silver jewel has large amounts of Hg and AgCl indicating amalgam method. In addition the natural AgS2 phases probably come from Nueva España (year 1772 in full production of silver in such time. The association of new analytical non-destructive techniques combines the

  9. Solving geological and historical puzzles with advanced gemologic techniques: The Franco Dávila (1772) precious opal case

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Guinea, J.; Gonzalez-Alcalde, J.; Furio, M.; Jorge, A.; Garrido, F.

    2016-07-01

    The large precious opal weighting 33 grams fitted in a silver jewel and exposed to visitors at the Museo Nacional de Ciencias Naturales (MNCN) is well documented in: (i) its own mounting (1772), (ii) at the 775 document of the Archive of the MNCN and (iii) the 395 specimen described in the of Pedro Franco Dávila catalogue. The X-ray diffractogram (XRD) performed onto the opal block is very similar to other opals of volcanic origin containing varied amounts of cristobalite, tridymite and amorphous silica. The Raman spectrum shows a band peaked at 242, 343 and 416 cm−1 associated with O-Si-O stretching groups; other spectral band peaked at 780 and 819 cm−1 corresponding to vibration of symmetrical O-Si-O rings of 3 and 4 link members, plus other minor bands. The Raman spectrum is also very similar to those observed in Mexican opals of volcanic origin containing an spectral band of stretching nodes ν1 (OH) at 3233, 3393, 3511, 3628 cm−1 related to OH groups with hydrogen bonds of isolated silanol groups. The interferometric confocal dual microscope 3D (MCI3D), which is a nondestructive facility of high resolution and LED technology reveals the geometry of graver tools on the silver jewel and the computed tomography X-ray highlights the opal cutting as a squared princess type and silver chloride infillings of a crack probably caused by a shock on a corner. Under the scanning electron microscope we observed barite, sealed veins of silica rich in Mn and opal with high contents of Al and K which, along with the historical data, the piece can be attributed to the historical site of opals hosted in Slovakia andesite rocks, this data explains the optical light behavior in the cabochon. The silver jewel has large amounts of Hg and AgCl indicating amalgam method. In addition the natural AgS2 phases probably come from Nueva España (year 1772) in full production of silver in such time. The association of new analytical non-destructive techniques combines the

  10. Quaternary biogenic opal records in the South China Sea: Linkages to East Asian monsoon, global ice volume and orbital forcing

    Institute of Scientific and Technical Information of China (English)

    WANG RuJian; JIAN ZhiMin; XIAO WenShen; TIAN Jun; LI JianRu; CHEN RongHua; ZHENG YuLong; CHEN JianFang

    2007-01-01

    Particulate fluxes investigated in the central South China Sea (SCS) during 1993-1996 indicate that opal flux can be used to show primary productivity change, which provides a foundation for tracing the evolutionary relationship between the surface productivity and East Asian monsoon in the SCS during the late Quaternary glacial and interglacial periods. Based on the studies of opal % and their mass accumulation rates (MAR) at the six sites recovered from the SCS during the "Resolution" ODP Leg 184 and "Sonne" 95 cruise of the Sino-Germany cooperation, opal % and their MARs increased evidently in the northern sites since 470-900 ka, and they enhanced and reduced, respectively, during the glacial and interglacial periods. Whereas they increased obviously in the southern sites since 420-450 ka,and they augmented and declined, respectively, during the interglacial and glacial periods. The variability in opal % and their MARs in the late Quaternary glacial cyclicity indicate the "seesaw" pattern of surface productivity in the SCS. The winter monsoon intensified during the glacial periods, surface productivity increased and decreased, respectively, in the northern and southern SCS. The summer monsoon strengthened during the interglacial periods, surface productivity increased and decreased,respectively, in the southern and northern SCS. The cross spectral analyses between the opal % in the northern and southern SCS during the Quaternary and global ice volume (δ18O) and orbital forcing (ETP) indicate that the East Asian winter and summer monsoons could be ascribed to the different drive mechanisms. On the orbital time scale, the global ice volume change could be a dominant factor for the winter monsoon intension and temporal variations. As compared with the winter monsoon, the correlative summer solar radiation with the obliquity and precession in the Northern Hemisphere could be a mostly controlling factor for the summer monsoon intension and temporal variations.

  11. Quaternary biogenic opal records in the South China Sea: Linkages to East Asian monsoon, global ice volume and orbital forcing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Particulate fluxes investigated in the central South China Sea (SCS) during 1993―1996 indicate that opal flux can be used to show primary productivity change, which provides a foundation for tracing the evolutionary relationship between the surface productivity and East Asian monsoon in the SCS during the late Quaternary glacial and interglacial periods. Based on the studies of opal % and their mass accumulation rates (MAR) at the six sites recovered from the SCS during the “Resolution” ODP Leg 184 and “Sonne” 95 cruise of the Sino-Germany cooperation, opal % and their MARs increased evidently in the northern sites since 470―900 ka, and they enhanced and reduced, respectively, during the glacial and interglacial periods. Whereas they increased obviously in the southern sites since 420―450 ka, and they augmented and declined, respectively, during the interglacial and glacial periods. The vari- ability in opal % and their MARs in the late Quaternary glacial cyclicity indicate the “seesaw” pattern of surface productivity in the SCS. The winter monsoon intensified during the glacial periods, surface productivity increased and decreased, respectively, in the northern and southern SCS. The summer monsoon strengthened during the interglacial periods, surface productivity increased and decreased, respectively, in the southern and northern SCS. The cross spectral analyses between the opal % in the northern and southern SCS during the Quaternary and global ice volume (δ 18O) and orbital forcing (ETP) indicate that the East Asian winter and summer monsoons could be ascribed to the different drive mechanisms. On the orbital time scale, the global ice volume change could be a dominant factor for the winter monsoon intension and temporal variations. As compared with the winter monsoon, the correlative summer solar radiation with the obliquity and precession in the Northern Hemisphere could be a mostly controlling factor for the summer monsoon intension and

  12. COMMERCIAL APPLICATION OF TOM OPAL 878L CATALYST FOR OLEFIN DECREASING%TOM OPAL 878L型降烯烃催化剂的工业应用

    Institute of Scientific and Technical Information of China (English)

    徐武清; 叶晓东

    2003-01-01

    介绍了洛阳分公司Ⅰ套催化裂化装置使用TOM OPAL 878L降汽油烯烃催化剂的情况.该剂在占系统催化剂藏量46%时进行的标定结果表明:该剂具有比较明显的降汽油烯烃效果,汽油烯烃体积分数由49.7%降到42%,下降了7.7个百分点,汽油辛烷值没有降低;产品分布得到改善,重油裂化能力强,干气和焦炭选择性好,干气产率降低了0.16个百分点,焦炭产率降低了0.81个百分点,轻质油收率增加了1.58个百分点,轻液体收率增加了2.36个百分点.

  13. Plasmonics of opalic surface: a combined near-and far-field approach

    CERN Document Server

    Lethiec, Clotilde; Popescu, Trajan; Frederich, Hugo; Ngoc, Phan; Yraola, Eduardo; Schwob, Catherine; Charra, Fabrice; Coolen, Laurent; Douillard, Ludovic; Maître, Agnès

    2016-01-01

    An opalic plasmonic sample, constituted by a hexagonal arrangement of metallized silica spheres, presents remarkable optical properties due to the mixing of periodic arrangement and singularities at the sphere touching points. It is therefore an interesting candidate for exploiting the excitation of both localized and propagating surface plasmons. Several channels of excitation based on these properties or exploiting a certain level of disorder are evidenced, opening new routes for the efficient excitation of plasmons on a wide spectral range. The versatility of such hybrid system is evidenced in the context of two complementary experiments: specular reflective spectrometry and photoemission electron microscopy. Both techniques offer different points of view on the same physical phenomenon and the link between them is discussed. Such experiments evidence the opportunities offered by these 2D hybrid materials in the context of nanophotonics.

  14. Radiological Shielding Design for the Neutron High-Resolution Backscattering Spectrometer EMU at the OPAL Reactor

    Science.gov (United States)

    Ersez, Tunay; Esposto, Fernando; Souza, Nicolas R. de

    2017-09-01

    The shielding for the neutron high-resolution backscattering spectrometer (EMU) located at the OPAL reactor (ANSTO) was designed using the Monte Carlo code MCNP 5-1.60. The proposed shielding design has produced compact shielding assemblies, such as the neutron pre-monochromator bunker with sliding cylindrical block shields to accommodate a range of neutron take-off angles, and in the experimental area - shielding of neutron focusing guides, choppers, flight tube, backscattering monochromator, and additional shielding elements inside the Scattering Tank. These shielding assemblies meet safety and engineering requirements and cost constraints. The neutron dose rates around the EMU instrument were reduced to < 0.5 µSv/h and the gamma dose rates to a safe working level of ≤ 3 µSv/h.

  15. Inclusions in precious Australian opals offer a unique access to Martian-like weathering processes

    Science.gov (United States)

    Roberts, Gemma; Rey, Patrice; Carter, Elizabeth

    2015-04-01

    Spectral signatures of the surface of Mars indicate a variety of hydrated minerals, including Al- and Fe/Mg-rich phyllosilicates, iron oxides, sulfates, and opaline silica. Their formation has been attributed to a long-lived low-temperature aqueous weathering history (e.g. Bishop et al., 2008; Ehlmann et al., 2013) followed by a period of intense acidic oxidative weathering (e.g. Carter et al., 2013). Very acidic weathering, driven by volcanic-derived sulfuric acid, is possible on a regional scale on Mars because of the lack of carbonate. On Earth, however, low-pH weathering on a regional scale is unusual because of the abundance of carbonate. Finding regional-scale Martian analogues on Earth is therefore a challenge. The Great Artesian Basin (GAB) in central Australia formed during the Early Cretaceous from the deposition of pyrite-rich volcaniclastic sediments in a cold, muddy, anoxic and shallow continental sea. Following mid-Cretaceous sea regression, a deep (~100 m) weathering profile recorded a protracted episode (~from 97 to 60 Ma) of oxidative weathering during continuous uplift and denudation, which stopped 60 myr ago. Since then, the weathering profile, which consists of Al- and Fe-rich phyllosilicates, iron oxides, and sulfates, has been constantly reworked. Interestingly, this profile hosts the bulk of the world's precious opal deposits. Since no opal deposit can be found in post-60 Ma rock formations, it is most likely that opal is part of the weathering profile developed during the drying out of central Australia. We analysed the mineral inclusions from six opal samples from the GAB to better document the early oxidative weathering. Using VNIR and Raman spectroscopy we were able to identify a variety of minerals including ferrihydrite, barite, gypsum and alunite replaced by goethite. This mineralogical assemblage is indicative of acidic oxidative conditions that points to Martian-like acidic weathering. We propose that acidity was derived from the

  16. Dark Current and Multipacting Capabilities in OPAL: Model Benchmarks and Applications

    CERN Document Server

    Wang, C; Yin, Z G; Zhang, T J

    2012-01-01

    Dark current and multiple electron impacts (multipacting), as for example observed in radio frequency (RF) structures of accelerators, are usually harmful to the equipment and the beam quality. These effects need to be suppressed to guarantee efficient and stable operation. Large scale simulations can be used to understand causes and develop strategies to suppress these phenomenas. We extend \\opal, a parallel framework for charged particle optics in accelerator structures and beam lines, with the necessary physics models to efficiently and precisely simulate multipacting phenomenas. We added a Fowler-Nordheim field emission model, two secondary electron emission models, developed by Furman-Pivi and Vaughan respectively, as well as efficient 3D boundary geometry handling capabilities. The models and their implementation are carefully benchmark against a non-stationary multipacting theory for the classic parallel plate geometry. A dedicated, parallel plate experiment is sketched.

  17. Carbon quantum dots coated BiVO{sub 4} inverse opals for enhanced photoelectrochemical hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Feng; Shen, Mingrong; Fang, Liang, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [College of Physics, Optoelectronics and Energy and Jiangsu Key Laboratory of Thin Films, Soochow University, Suzhou 215006 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn, E-mail: lfang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Wang, Junling [School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2015-04-13

    Carbon quantum dots (CQDs) coated BiVO{sub 4} inverse opal (io-BiVO{sub 4}) structure that shows dramatic improvement of photoelectrochemical hydrogen generation has been fabricated using electrodeposition with a template. The io-BiVO{sub 4} maximizes photon trapping through slow light effect, while maintaining adequate surface area for effective redox reactions. CQDs are then incorporated to the io-BiVO{sub 4} to further improve the photoconversion efficiency. Due to the strong visible light absorption property of CQDs and enhanced separation of the photoexcited electrons, the CQDs coated io-BiVO{sub 4} exhibit a maximum photo-to-hydrogen conversion efficiency of 0.35%, which is 6 times higher than that of the pure BiVO{sub 4} thin films. This work is a good example of designing composite photoelectrode by combining quantum dots and photonic crystal.

  18. Inverse Opal Photonic Crystals as a Strategy to Improve Photocatalysis: Underexplored Questions.

    Science.gov (United States)

    Curti, Mariano; Schneider, Jenny; Bahnemann, Detlef W; Mendive, Cecilia B

    2015-10-01

    The structuring of materials in the form of photonic crystals for photocatalytic applications is a quite new strategy aiming to enhance the performance of the photocatalysts at wavelength ranges where their absorption is poor. It is of particular interest to successfully manufacture an efficient photocatalytic system that could make use of solar light. Thus, the key of the strategy is the "slow photon effect", occurring at the edges of a forbidden band for photons. In this Perspective we have chosen some questions that we consider of relevance and that are well worth being addressed both theoretically and experimentally. It is the aim of this discussion to eventually lead to a more productive use of inverse opals as photonic photocatalytic materials.

  19. Enhancement of Tb-Yb quantum cutting emission by inverse opal photonic crystals

    Science.gov (United States)

    Wang, Qi; Qiu, Jianbei; Song, Zhiguo; Yang, Zhengwen; Yin, Zhaoyi; Zhou, Dacheng; Wang, Siqin

    2016-04-01

    Yb3+, Tb3+ co-doped YPO4 inverse opal photonic crystal was prepared directly by sol-gel technique in combination with self-assembly method. With the influence of the photonic band gap, quantum cutting emission of Tb3+, Yb3+ was investigated in photonic crystals by photoluminescence and fluorescence lifetime. The result clearly shows that, when the spontaneous emission of donor Tb3+ is inhibited by photonic band gap, Tb3+-Yb3+ quantum cutting quantum efficiency from Tb3+ to Yb3+ could be enhanced from 131.2% to 140.5%. The mechanisms for the influence of the photonic band gap on quantum cutting process of Tb3+ and Yb3+ are discussed. We believe that the present work will be valuable for the foundational study of quantum cutting energy transfer process and application of quantum cutting optical devices in spectral modification materials for silicon solar cells.

  20. Impact of opal nanoconfinement on electronic properties of sodium particles: NMR studies

    Energy Technology Data Exchange (ETDEWEB)

    Charnaya, E.V., E-mail: charnaya@live.com [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); Institute of Physics, St. Petersburg State University, St. Petersburg, 198504 (Russian Federation); Lee, M.K. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); MoST Instrument Center at NCKU, Tainan, 70101 Taiwan (China); Chang, L.J. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); Kumzerov, Yu.A.; Fokin, A.V. [A.F. Ioffe Physico-Technical Institute RAS, St. Petersburg, 194021 (Russian Federation); Samoylovich, M.I. [Moscow Institute of Physics and Technology, Moscow, 141700 (Russian Federation); Bugaev, A.S. [CSR Institute of Technology “Technomash”, Moscow, 121108 (Russian Federation)

    2015-03-20

    The {sup 23}Na Knight shift of NMR line which is highly correlated with the electron spin susceptibility and density of states at the Fermi level was studied for the sodium loaded opal. The measurements were carried out within a temperature range from 100 to 400 K for solid and melted confined sodium nanoparticles. The NMR line below 305 K was a singlet with the Knight shift reduced compared to that in bulk. Above this temperature the NMR line split reproducibly into two components with opposite trends in the Knight shift temperature dependences which evidenced a nanoconfinement-induced transformation and heterogeneity in the electron system. The findings were suggested to be related to changes in the topology of the Fermi surface.

  1. Enhanced spontaneous emission from nanodiamond colour centres on opal photonic crystal

    CERN Document Server

    Inam, Faraz A; Bradac, Carlo; Stewart, Luke; Withford, Michael J; Dawes, Judith M; Rabeau, James R; Steel, Michael J

    2011-01-01

    Colour centres in diamond are promising candidates as a platform for quantum technologies and biomedical imaging based on spins and/or photons. Controlling the emission properties of colour centres in diamond is a key requirement for developing efficient single photon sources with high collection efficiency. A number of groups have produced enhancement in the emission rate over narrow wavelength ranges by coupling single emitters in nanodiamond crystals to resonant electromagnetic structures. Here we characterise in detail the spontaneous emission rates of nitrogen-vacancy centres positioned in various locations on a structured substrate. We show an average factor of 1.5 enhancement of the total emission rate when nanodiamonds are on an opal photonic crystal surface, and observe changes in the lifetime distribution. We present a model to explain these observations and associate the lifetime properties with dipole orientation and polarization effects.

  2. Mimicking natural fibrous structures of opals by means of a microemulsion-mediated hydrothermal method.

    Science.gov (United States)

    Hassan, Natalia; Verdinelli, Valeria; Ruso, Juan M; Messina, Paula V

    2011-07-19

    Silica-based nanomaterials are of great interest because of their potential applications in constructing electronic and optoelectronic nanodevices. Especially significant are those that combine the properties of photonic crystal with a fibrous semiconductor structure. Here we report the use of microemulsion droplet systems as a simple and controllable route for the synthesis of 3D opals materials with an unusual fibrous microstructure similar to those that exist in nature. By this method, we demonstrate the creation of very long fibrils of 30-50 nm diameter and more than 20 μm length showing simultaneous short and long wavelength light emissions and band gap values (5.50 and 4.41 eV) comparable to those obtained for silicon-based metal oxide semiconductors.

  3. Search for Supersymmetric Particles with the OPAL Detector at LEP2

    CERN Document Server

    Kanaya, N

    A search of Supersymmetric particles was performed using the data collected in 1999 and 2000 by the Opal detector at the LEP2 e+e- collider. The center-of-mass energies ranged from 192 GeV to 209 GeV, and the data analyzed correspond to an integrated luminosity of 432 pb-1. Supersymmetric models permit a large number of different experimental final states which should all be investigated. The search presented here is sensitive to final states with photons plus additional detector activity with missing energy. these topologies are characteristic of events expected in Gauge-Mediated Supersymmetry Breaking (GMSB) models. No significant evidence for their existence is observed. Finally, using various search results at centre-of-mass energy of 189 GeV, constraints on the parameters have been given within the framework of the minimal GMSB model.

  4. Upgrade of the neutron guide system at the OPAL Neutron Source

    Science.gov (United States)

    Rodriguez, D. Martin; Kennedy, S. J.; Klose, F.

    2010-11-01

    The new research reactor at ANSTO (OPAL) is operating with seven neutron beam instruments in the user programme and three more under construction. The reactor design provides for expansion of the facility to eighteen instruments, and much of the basic infrastructure is already in place. However, an expansion of the neutron guide system is needed for further beam instruments. For this purpose, several possibilities are under consideration, such as insertion of multi-channel neutron benders in the existing cold guides or the construction of a new elliptic cold guide. In this work Monte Carlo (MC) simulations have been used to evaluate performance of these guide configurations. Results show that these configurations can be competitive with the best instruments in the world.

  5. Graphene-embedded 3D TiO2 inverse opal electrodes for highly efficient dye-sensitized solar cells: morphological characteristics and photocurrent enhancement.

    Science.gov (United States)

    Kim, Hye-Na; Yoo, Haemin; Moon, Jun Hyuk

    2013-05-21

    We demonstrated the preparation of graphene-embedded 3D inverse opal electrodes for use in DSSCs. The graphene was incorporated locally into the top layers of the inverse opal structures and was embedded into the TiO2 matrix via post-treatment of the TiO2 precursors. DSSCs comprising the bare and 1-5 wt% graphene-incorporated TiO2 inverse opal electrodes were compared. We observed that the local arrangement of graphene sheets effectively enhanced electron transport without significantly reducing light harvesting by the dye molecules. A high efficiency of 7.5% was achieved in DSSCs prepared with the 3 wt% graphene-incorporated TiO2 inverse opal electrodes, constituting a 50% increase over the efficiencies of DSSCs prepared without graphene. The increase in efficiency was mainly attributed to an increase in J(SC), as determined by the photovoltaic parameters and the electrochemical impedance spectroscopy analysis.

  6. 206Pb-230Th-234U-238U and 207Pb-235U geochronology of Quaternary opal, Yucca Mountain, Nevada

    Science.gov (United States)

    Neymark, Leonid A.; Amelin, Yuri V.; Paces, James B.

    2000-01-01

    U–Th–Pb isotopic systems have been studied in submillimeter-thick outermost layers of Quaternary opal occurring in calcite–silica fracture and cavity coatings within Tertiary tuffs at Yucca Mountain, Nevada, USA. These coatings preserve a record of paleohydrologic conditions at this site, which is being evaluated as a potential high-level nuclear waste repository. The opal precipitated from groundwater is variably enriched in 234U (measured 234U/238U activity ratio 1.124–6.179) and has high U (30–313 ppm), low Th (0.008–3.7 ppm), and low common Pb concentrations (measured 206Pb/204Pb up to 11,370). It has been demonstrated that the laboratory acid treatment used in this study to clean sample surfaces and to remove adherent calcite, did not disturb U–Th–Pb isotopic systems in opal. The opal ages calculated from 206Pb∗/238U and 207Pb∗/235U ratios display strong reverse discordance because of excess radiogenic 206Pb∗ derived from the elevated initial 234U. The data are best interpreted using projections of a new four-dimensional concordia diagram defined by 206Pb∗/238U, 207Pb∗/235U, 234U/238Uactivity, and 230Th/238Uactivity. Ages and initial 234U/238U activity ratios have been calculated using different projections of this diagram and tested for concordance. The data are discordant, that is observed 207Pb∗/235U ages of 170 ± 32 (2σ) to 1772 ± 40 ka are systematically older than 230Th/U ages of 34.1 ± 0.6 to 452 ± 32 ka. The age discordance is not a result of migration of uranium and its decay products under the open system conditions, but a consequence of noninstantaneous growth of opal. Combined U–Pb and 230Th/U ages support the model of slow mineral deposition at the rates of millimeters per million years resulting in layering on a scale too fine for mechanical sampling. In this case, U–Pb ages provide more accurate estimates of the average age for mixed multiage samples than 230Th/U ages, because ages based on shorter

  7. Can citizen science produce good science? Testing the OPAL Air Survey methodology, using lichens as indicators of nitrogenous pollution.

    Science.gov (United States)

    Tregidgo, Daniel J; West, Sarah E; Ashmore, Mike R

    2013-11-01

    Citizen science is having increasing influence on environmental monitoring as its advantages are becoming recognised. However methodologies are often simplified to make them accessible to citizen scientists. We tested whether a recent citizen science survey (the OPAL Air Survey) could detect trends in lichen community composition over transects away from roads. We hypothesised that the abundance of nitrophilic lichens would decrease with distance from the road, while that of nitrophobic lichens would increase. The hypothesised changes were detected along strong pollution gradients, but not where the road source was relatively weak, or background pollution relatively high. We conclude that the simplified OPAL methodology can detect large contrasts in nitrogenous pollution, but it may not be able to detect more subtle changes in pollution exposure. Similar studies are needed in conjunction with the ever-growing body of citizen science work to ensure that the limitations of these methods are fully understood.

  8. Production of luster glaze on opal tableware using zarinfam technique and characterization of its structure and color

    Science.gov (United States)

    Razavi, Fahime; Rashidi Huyeh, Majid; Ghahari, Mahdi

    2016-05-01

    Lusters are potters that have attracted much attention due to their specific optical features, one of the most important of which is their sparkle that appears in various colors at different angles. This effect linked to the multilayer structure of luster and the presence of metallic nanoparticles in enamel layer. In this research, luster glaze was produced on Opal tableware, manufactured in Mahfam Jam Co., using Zarinfam technique. SEM micrograph image of the samples indicated that the glaze forms a multilayer structure, on the Opal tableware surface, consisting of a glassy superficial layer of some tens of nanometers and a composite layer of some hundreds of nanometers. The enamel composite layer contains silver nanoparticles embedded in a silica medium. Employing a multilayer model, we studied the influence of different parameters such as luster enamel thickness, nanoparticles volume fraction in enamel, nanoparticle size, observe angle, and glass layer thickness on luster color.

  9. Variations of opal accumulation rates and paleoproductivity over the past 12 Ma at ODP Site 1143,southern South China Sea

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The biogenic silica analysis was performed on 463 samples from ODP 184 Site 1143, the southern South China Sea. The results show that the opal content and MAR evidently increased between 12.3 and 5.7 Ma, which was contemporary with the high carbonate and total MARs, reflecting the high biogenic productivity in the late Miocene.This demonstrates the occurrence of the late Miocene "Biogenie Bloom Event" in the southern South China Sea, corresponding to the late Miocene-early Pliocene "Biogenic Bloom Event" in the Indian-Pacific Ocean. The increases of opal content and MAR after the middle Pleistocene (about 0.7 Ma)is inferred to result from the enhanced upwelling and nutrient supply, which was induced by the intensified monsoon circulation after the "Mid-Pleistocene Revolution".

  10. Fabrication and optical properties of Alq 3 doped PMMA microsphere arrays templated by ZnO inverse opal structure

    Science.gov (United States)

    Fu, Ming; Deng, Lier; Zhao, Ailun; Wang, Yongsheng; He, Dawei

    2010-07-01

    PMMA microsphere arrays are fabricated by a double replicating method with common used polystyrene colloidal crystal template. High quality ZnO inverse opals formed by electrodeposition play the key role between the PMMA microsphere arrays and polystyrene colloidal crystals. The electrodeposition method has advantage on fabricating IO structures with high solid fraction. After the subsequently in-situ polymerization of MMA in the voids of ZnO inverse opals, the ZnO is removed by hydrochloric acid solution. Microsphere arrays fabricated by PMMA or PMMA doped with Alq 3 are prepared. Reflection stop bands are detected from the formed PMMA microsphere arrays. Solid fraction from 37% to 50% of the PMMA arrays can be formed by different in-situ polymerization modes of MMA. The photoluminescence of Alq 3 in the PMMA spheres is partly suppressed at the wavelength of the photonic stop band induced by PMMA arrays.

  11. CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

    OpenAIRE

    2015-01-01

    The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microsc...

  12. Geohydrologic reconnaissance of Lake Mead National Recreation Area; Las Vegas Wash to Opal Mountain, Nevada

    Science.gov (United States)

    Laney, R.L.

    1981-01-01

    The study is a geohydrologic reconnaissance of about 170 square miles in the Lake Mead National Recreation Area from Las Vegas Wash to Opal Mountain, Nevada. The study is one of a series that describes the geohydrology of the recreation area and that indentifies areas where water supplies can be developed. Precipitation in this arid area is about 5 inches per year. Streamflow is seasonal and extremely variable except for that in the Colorado River, which adjoins the area. Pan evaporation is more than 20 times greater than precipitation; therefore, regional ground-water supplies are meager except near the Colorado River, Lake Mead, and Lake Mohave. Large ground-water supplies can be developed near the river and lakes, and much smaller supplies may be obtained in a few favorable locations farther from the river and lakes. Ground water in most of the areas probably contains more than 1,000 milligrams per liter of dissolved solids, but water that contains less than 1,000 milligrams per liter of dissolved solids can be obtained within about 1 mile of the lakes. Crystalline rocks of metamorphic, intrusive and volcanic origin crop out in the area. These rocks are overlain by conglomerate and mudstone of the Muddy Creek Formation, gravel and conglomerate of the older alluvium, and sand and gravel of the Chemehuevi Formation and younger alluvium. The crystalline rocks, where sufficiently fractured, yield water to springs and would yield small amounts of water to favorably located wells. The poorly cemented and more permeable beds of the older alluvium, Chemehuevi Formation, and younger alluvium are the better potential aquifers, particularly along the Colorado River and Lakes Mead and Mohave. Thermal springs in the gorge of the Colorado River south of Hoover Dam discharge at least 2,580 acre-feet per year of water from the volcanic rocks and metamorphic and plutonic rocks. The discharge is much greater than could be infiltrated in the drainage basin above the springs

  13. Oxygen persufflation as adjunct in liver preservation (OPAL: Study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Scherag Andre

    2011-10-01

    Full Text Available Abstract Background Early graft dysfunction due to preservation/reperfusion injury represents a dramatic event after liver transplantation. Enhancement of donor organ criteria, in order to cope with the ever increasing donor shortage, further increases graft susceptibility to ischemic alterations. Major parts of post-preservation injury, however, occur at the time of warm reperfusion but not during ischemic storage; successful reperfusion of ischemic tissue in turn depends on an adequate redox and intracellular signal homeostasis. The latter has been shown experimentally to be favorably influenced by oxygen persufflation within short time spans. Thus viability of marginally preserved liver grafts could still be augmented by transient hypothermic reconditioning even after normal procurement and static cold storage. The present study is aimed to confirm the conceptual expectations, that hypothermic reconditioning by gaseous oxygen persufflation is a useful method to suppress injurious cellular activation cascades and to improve post-ischemic recovery of marginally preserved liver grafts. Methods/Design OPAL is a prospective single center randomized proof of concept study, including two parallel groups in a total of 116 liver transplant patients. The effect of an in hospital treatment of the isolated liver graft by 2 hours of oxygen persufflation immediately prior to transplantation will be assesses as compared to standard procedure (cold storage without further intervention. The primary endpoint is the peak transaminase serum level (AST during the first three days after transplantation as a surrogate readout for parenchymal liver injury. Other outcomes comprise patient and graft survival, time of intensive care requirement, hepatic tissue perfusion 1h after revascularisation, early onset of graft dysfunction based on coagulation parameters, as well as the use of a refined scoring-system for initial graft function based on a multi-parameter (AST

  14. Cell-friendly inverse opal-like hydrogels for a spatially separated co-culture system.

    Science.gov (United States)

    Kim, Jaeyun; Bencherif, Sidi A; Li, Weiwei Aileen; Mooney, David J

    2014-09-01

    Three-dimensional macroporous scaffolds have extensively been studied for cell-based tissue engineering but their use is mostly limited to mechanical support for cell adhesion and growth on the surface of macropores. Here, a templated fabrication method is described to prepare cell-friendly inverse opal-like hydrogels (IOHs) allowing both cell encapsulation within the hydrogel matrix and cell seeding on the surface of macropores. Ionically crosslinked alginate microbeads and photocrosslinkable biocompatible polymers are used as a sacrificial template and as a matrix, respectively. The alginate microbeads are easily removed by a chelating agent, with minimal toxicity for the encapsulated cells during template removal. The outer surface of macropores in IOHs can also provide a space for cell adherence. The cells encapsulated or attached in IOHs are able to remain viable and to proliferate over time. The elastic modulus and cell-adhesion properties of IOHs can be easily controlled and tuned. Finally, it is demonstrated that IOH can be used to co-culture two distinct cell populations in different spatial positions. This cell-friendly IOH system provides a 3D scaffold for organizing different cell types in a controllable microenvironment to investigate biological processes such as stem cell niches or tumor microenvironments.

  15. Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.

    Science.gov (United States)

    Zhao, Xiangwei; Xue, Jiangyang; Mu, Zhongde; Huang, Yin; Lu, Meng; Gu, Zhongze

    2015-10-15

    Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL.

  16. Zinc oxide inverse opal electrodes modified by glucose oxidase for electrochemical and photoelectrochemical biosensor.

    Science.gov (United States)

    Xia, Lei; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; Xu, Lin; Song, Hongwei

    2014-09-15

    The ZnO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method using the polymethylmethacrylate (PMMA) as a template. For glucose detection, glucose oxidase (GOD) was further immobilized on the inwall and surface of the IOPCs. The biosensing properties toward glucose of the Nafion/GOD/ZnO IOPCs modified FTO electrodes were carefully studied and the results indicated that the sensitivity of ZnO IOPCs modified electrode was 18 times than reference electrode due to the large surface area and uniform porous structure of ZnO IOPCs. Moreover, photoelectrochemical detection for glucose using the electrode was realized and the sensitivity approached to 52.4 µA mM(-1) cm(-2), which was about four times to electrochemical detection (14.1 µA mM(-1) cm(-2)). It indicated that photoelectrochemical detection can highly improve the sensor performance than conventional electrochemical method. It also exhibited an excellent anti-interference property and a good stability at the same time. This work provides a promising approach for realizing excellent photoelectrochemical biosensor of similar semiconductor photoelectric material.

  17. Hematite-based photoelectrochemical water splitting supported by inverse opal structures of graphene.

    Science.gov (United States)

    Yoon, Ki-Yong; Lee, Jung-Soo; Kim, Kwanghyun; Bak, Chang Hong; Kim, Sun-I; Kim, Jin-Baek; Jang, Ji-Hyun

    2014-12-24

    By coupling α-Fe2O3 with a 3D graphene inverse opal (3D-GIO) conducting electrode, the short diffusion length of carriers and low absorption coefficient in α-Fe2O3 for photoelectrochemical applications were successfully addressed. GIO was directly grown on FTO substrate under low temperature conditions, removing the need for a graphene transfer process. α-Fe2O3 nanoparticles (NPs) were hydrothermally deposited on the surface of GIO, creating α-Fe2O3/GIO. The photocurrent density of α-Fe2O3/GIO in water splitting reactions reached 1.62 mA/cm(2) at 1.5 V vs RHE, which is 1.4 times greater than that of optimized α-Fe2O3. The EIS and IPCE data confirm reduced electron-hole recombination and fast electron transfer processes due to the short distance between active materials and the conducting electrode in the α-Fe2O3/GIO system. Our result may pave the way for designing devices in advanced energy conversion applications as well as a high efficiency hematite-based PEC system.

  18. 神圣华丽话欧泊%The Sacred and Magnificent Opal

    Institute of Scientific and Technical Information of China (English)

    涂泽时

    2001-01-01

    “欧泊”是“蛋白石”(OPAL)的英文译音.源于拉丁文(OPALUS).意思是”集宝石之美于一身”,作为金色十月的诞辰石.可见其华丽之极。实际上蛋白石中能做宝石的极少.而只有能做宝石的才能称之为“欧泊”.其最大的特点是具有绚丽夺目的变幻色彩.古罗马自然科学家普林尼描述道:欧泊五彩缤纷.美不胜收,有些欧泊石之美不亚于画家的调色板.另一些则不亚于硫磺之火焰或燃油之火舌,是希望之火和幸福的象征。

  19. Properties of Vulcanized Polyisoprene Rubber Composites Filled with Opalized White Tuff and Precipitated Silica

    Directory of Open Access Journals (Sweden)

    Suzana Samaržija-Jovanović

    2014-01-01

    Full Text Available Opalized white tuff (OWT with 40 μm average particle size and 39.3 m2/g specific surface area has been introduced into polyisoprene rubber (NR. Their reinforcing effects were evaluated by comparisons with those from precipitated silica (PSi. The cure characteristic, apparent activation energy of cross-link (Eac and reversion (Ear, and mechanical properties of a variety of composites based on these rubbers were studied. This was done using vulcanization techniques, mechanical testing, and scanning electron microscopy (SEM. The results showed that OWT can greatly improve the vulcanizing process by shortening the time of optimum cure (tc90 and the scorch time (ts2 of cross-linked rubber composites, which improves production efficiency and operational security. The rubber composites filled with 50 phr of OWT were found to have good mechanical and elastomeric properties. The tensile strengths of the NR/OWT composites are close to those of NR/PSi composites, but the tear strength and modulus are not as good as the corresponding properties of those containing precipitated silica. Morphology results revealed that the OWT is poorly dispersed in the rubber matrix. According to that, the lower interactions between OWT and polyisoprene rubber macromolecules are obtained, but similar mechanical properties of NR/OWT (100/50 rubber composites compared with NR/PSi (100/50 rubber composites are resulted.

  20. Ultrasensitive Sensing Material Based on Opal Photonic Crystal for Label-Free Monitoring of Transferrin.

    Science.gov (United States)

    Wu, Enqi; Peng, Yuan; Zhang, Xihao; Bai, Jialei; Song, Yanqiu; He, Houluo; Fan, Longxing; Qu, Xiaochen; Gao, Zhixian; Liu, Ying; Ning, Baoan

    2017-02-22

    A new opal photonic crystal (PC) sensing material, allowing label-free detection of transferrin (TRF), is proposed in the current study. This photonic crystal was prepared via a vertical convective self-assembly method with monodisperse microspheres polymerized by methyl methacrylate (MMA) and 3-acrylamidophenylboronic acid (AAPBA). FTIR, TG, and DLS were used to characterize the components and particle size of the monodisperse microspheres. SEM was used to observe the morphology of the PC. The diffraction peak intensity decreases as the TRF concentration increase. This was due to the combination of TRF to the boronic acid group of the photonic crystal. After condition optimization, a standard curve was obtained and the linear range of TRF concentration was from 2 × 10(-3) ng/mL to 200 ng/mL. Measurement of TRF concentration in simulated urine sample was also investigated using the sensing material. The results indicated that the PC provided a cheap, label-free, and easy-to-use alternative for TRF determination in clinical diagnostics.

  1. A Study of charm quark production in beauty quark decays with the OPAL detector at LEP

    CERN Document Server

    Waller, David

    2003-01-01

    The production of charm quarks in beauty quark decays has been studied with the OPAL detector at the Large Electron Positron collider near Geneva, Switzerland. The branching ratio Br(b -1 DDX) has been measured using hadronic zo decays collected between 1993 and 1995. Here b refers to the admixture of weakly decaying hadrons containing ab quark that are produced in electron-positron annihilations at a centre of mass energy equal to the mass of the zo boson. The impact parameter significance of tracks in tagged b-jets is used to differentiate b -1 DDX decays from other decays. The result is Br(b -1 DDX) = (10.0 ± 3.2(stat.)~~:~(syst. det.)~~~04 (syst. phys.))%. where syst. det. is the systematic uncertainty due to the modelling of the detector, and syst. phys. is the systematic uncertainty due to the modelling of the underlying particle physics. Using this result, the average number of charm and anti-charm quarks produced in a beauty quark decay, nc, is found to be l.12~8:i6- Ill

  2. Search for Invisibly Decaying Higgs Bosons with Large Decay Width Using the OPAL Detector at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostu, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Bailari, T.; Barlow, R.J.; Batly, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A., Jr.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Seuster, R.; Shears, T.G.; shen, B.C.; sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2007-01-01

    This paper describes a topological search for an invisibly decaying Higgs boson,H, produced via the Bjorken process (e+e- -> HZ). The analysis is based on data recorded using the OPAL detector at LEP at centre-of-mass energies from 183 to 209 GeV corresponding to a total integrated luminosity of 629pb-1. In the analysis only hadronic decays of the Z boson are considered. A scan over Higgs boson masses from 1 to 120 GeV and decay widths from 1 to 3000 GeV revealed no indication for a signal in the data. From a likelihood ratio of expected signal and Standard Model background we determine upper limits on cross-section times branching ratio to an invisible final state. For moderate Higgs boson decay widths, these range from about 0.07pb Mh = 60GeV) to 0.57pb (Mh = 114GeV). For decay widths above 200GeV the upper limits are of the order of 0.15pb. The results can be interpreted in general scenarios predicting a large invisible decay width of the Higgs boson. As an example we interpret the results in the so-called...

  3. Determination of $\\alpha_{s}$ using Jet Rates at LEP with the OPAL detector

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2006-01-01

    Hadronic events produced in e+e- collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to energies of 91 GeV, 130-136 GeV and 161-209 GeV. The jet rates were determined using four different jet-finding algorithms (Cone, JADE, Durham and Cambridge). The differential two-jet rate and the average jet rate with the Durham and Cambridge algorithms were used to measure alpha(s) in the LEP energy range by fitting an expression in which order alpah_2s calculations were matched to a NLLA prediction and fitted to the data. Combining the measurements at different centre-of-mass energies, the value of alpha_s (Mz) was determined to be alpha(s)(Mz)=0.1177+-0.0006(stat.)+-0.0012$(expt.)+-0.0010(had.)+-0.0032

  4. Implications for Late Pleistocene Mastodon Diet from Opal Phytoliths in Tooth Calculus

    Science.gov (United States)

    Gobetz, Katrina E.; Bozarth, Steven R.

    2001-03-01

    Calculus removed from the molar teeth of four American mastodons (Mammut americanum) contained opal phytoliths which reflect major dietary components. Three samples contained abundant grass phytoliths (ca. 86% of total), with long cells and trapezoidal pooid short cells dominant (ca. 25 and 31%, respectively). Dicot phytoliths from hackberry (Celtis sp.) seeds and indeterminate deciduous trees were rare (1-3%), though well preserved, whereas phytoliths from conifer trees were not recognizable in any of the samples. Comparative analysis of calculus from modern and fossil browsers and mixed feeders implies that dicots and conifers are nearly invisible in the phytolith record. This scarcity may result from poor preservation, low silica production in woody taxa, and/or animals' selection of young, silica-poor leaves and shoots. However, abundant grass phytoliths in the mixed feeders suggest that presence versus absence of grass phytoliths may distinguish mixed feeders and grazers from browsers. Mastodons are traditionally considered browsers, but grass phytolith assemblages in three individual mastodons contained similarly high concentrations of pooids, suggesting that these grasses were a significant part of the diet. Abundant pooid phytoliths, in addition to diatoms, indicate that these mastodons grazed in a cool, moist late Pleistocene environment, possibly near water.

  5. Search for the production of single top quarks using the OPAL detector

    CERN Document Server

    Leins, Axel; Dunnweber, W.

    2002-01-01

    Innerhalb des sogenannten Standardmodells (SM) der Teilchenphysik ist der Prozess der Flavour-andernden neutralen Str ¨ ome (FCNC) auf Born-Niveau verboten, und nur ¨ uber Prozesse h ¨ oherer Ordnung m ¨ oglich. FCNC-Prozesse sind daher extrem unter- ¨ druckt und sehr selten. Experimentell konnte dies f ¨ ur die ersten beiden Generationen ¨ von Quarks bestatigt werden. F ¨ ur die dritte Generation, speziell f ¨ ur das Top-Quark, ¨ existieren bisher nur wenige experimentelle Erkenntnisse uber FCNC-Prozesse. Durch ¨ theoretische Erweiterungen des SM konnen, aufgrund der extrem großen Masse des ¨ Top-Quarks und der damit verbundenen Sonderstellung, FCNC-Prozesse fur Top- ¨ Quarks vorhergesagt werden, die um mehrere Großenordnungen gegen ¨ uber dem SM ¨ erhoht sind. ¨ In dieser Arbeit wird nach der Produktion einzelner Top-Quarks uber ¨ Flavourandernde neutrale Str ¨ ome mit den Daten des OPAL-Detektors am e ¨ e -Speicherring LEP gesucht. Hierzu wird im hadronischen Zerfallskanal des W-Bosons...

  6. Ag Nanoparticle/Polydopamine-Coated Inverse Opals as Highly Efficient Catalytic Membranes.

    Science.gov (United States)

    Choi, Gwan H; Rhee, Do Kyung; Park, A Reum; Oh, Min Jun; Hong, Sunghwan; Richardson, Joseph J; Guo, Junling; Caruso, Frank; Yoo, Pil J

    2016-02-10

    Polymeric three-dimensional inverse-opal (IO) structures provide unique structural properties useful for various applications ranging from optics to separation technologies. Despite vast needs for IO functionalization to impart additional chemical properties, this task has been seriously challenged by the intrinsic limitation of polymeric porous materials that do not allow for the easy penetration of waterborne moieties or precursors. To overcome this restriction, we present a robust and straightforward method of employing a dipping-based surface modification with polydopamine (PDA) inside the IO structures, and demonstrate their application to catalytic membranes via synthetic incorporation of Ag nanoparticles. The PDA coating offers simultaneous advantages of achieving the improved hydrophilicity required for the facilitated infiltration of aqueous precursors and successful creation of nucleation sites for a reduction of growth of the Ag nanoparticles. The resulting Ag nanoparticle-incorporated IO structures are utilized as catalytic membranes for the reduction of 4-nitrophenol to its amino derivatives in the presence of NaBH4. Synergistically combined characteristics of high reactivity of Ag nanoparticles along with a greatly enhanced internal surface area of IO structures enable the implementation of remarkably improved catalytic performance, exhibiting a good conversion efficiency greater than 99% while minimizing loss in the membrane permeability.

  7. Untersuchung perturbativer und nichtperturbativer Struktur der Momente hadronischer Ereignisformvariablen mit den Experimenten JADE und OPAL

    CERN Document Server

    Pahl, Christoph Johannes

    2007-01-01

    In Hadronproduktionsdaten der e+e− - Vernichtungsexperimente JADE und OPAL messen wir die ersten f¨unf Momente von zw¨olf hadronischen Ereignisformvariablen bei Schwerpunktsenergien von 14 bis 207GeV. Aus dem Vergleich der QCD NLO-Vorhersage mit den mittels MC-Modellen um Hadronisierung korrigierten Daten erhalten wir den Referenzwert der starken Kopplung αs(MZ0) = 0.1254 ± 0.0007(stat.) ± 0.0010(exp.)+0.0009 −0.0023(had.)+0.0069 −0.0053(theo.) . F¨ur einige, insbesondere h¨ohere, Momente sind systematische Unzul¨anglichkeiten in der QCD NLO-Vorhersage erkenntlich. Simultane Fits an zwei Momente unter Annahme identischer Renormierungsskalen ergeben Skalenwerte von xμ=0.057 bis xμ=0.196 . Wir pr¨ufen Vorhersagen verschiedener nichtperturbativer Modelle. Aus der Single Dressed Gluon - N¨aherung ergibt sich eine perturbative Vorhersage in O(α5 s ) mit zu vernachl¨assigender Energiepotenzkorrektur, die den Mittelwert von Thrust auf Hadronniveau gut beschreibt mit αs(MZ0) = 0.1186 ± 0.0007(st...

  8. Changes in opal fluxes along the northwest African margin during the last glacial period; linking high and low latitude patterns of productivity

    Science.gov (United States)

    Bradtmiller, L. I.; Galgay, M.; McGee, D.; Kinsley, C. W.; Anderson, R. F.

    2014-12-01

    Recent studies have proposed competing hypotheses to explain increased opal fluxes in high and low latitudes during the most recent deglaciation. Anderson et al. (2009) rely on increased wind-driven upwelling in the Southern Ocean to explain the increased availability of Si in both the Southern Ocean and tropical thermoclines, leading to increased opal fluxes in both regions coincident with the deglacial rise in CO2. Meckler et al. (2013) suggest that a decrease in the presence of North Atlantic intermediate water (GNAIW) during the deglaciation allowed Si-rich southern-sourced waters to fill the tropical Atlantic leading to increased opal burial. We attempt to distinguish between these two mechanisms by reconstructing opal fluxes and fluxes of windblown dust over the past ~65ka at four sites along the northwest African margin. The records include the deglaciation, including Heinrich Event 1 (H1) and the Younger Dryas (YD), as well as several earlier Heinrich events. We find that opal and dust fluxes increase simultaneously during the deglaciation, and more highly resolved cores record H1 and the YD as distinct peaks within the deglaciation. Furthermore, opal and dust fluxes scale approximately linearly with one another during these events. We observe opal peaks associated with most Heinrich Events through H6. Finally, we observe a strong similarity between patterns of opal flux in the Southern Ocean and along the African Margin. This suggests that the pattern of diatom productivity and opal flux along the African Margin reflects a combination of changes in wind strength due to shifting temperature gradients, and changes in the export of silica-rich water from the Southern Ocean, both as a result of the global scale climate changes associated with Heinrich Events. Anderson, R. F., S. Ali, L. I. Bradtmiller, S. H. H. Nielsen, M. Q. Fleisher, B. E. Anderson and L. H. Burckle. Wind-Driven Upwelling in the Southern Ocean and the Deglacial Rise in Atmospheric CO2

  9. Surveying the citizen science landscape: an exploration of the design, delivery and impact of citizen science through the lens of the Open Air Laboratories (OPAL) programme.

    Science.gov (United States)

    Davies, Linda; Fradera, Roger; Riesch, Hauke; Lakeman-Fraser, Poppy

    2016-07-22

    This paper provides a short introduction to the topic of citizen science (CS) identifying the shift from the knowledge deficit model to more inclusive, participatory science. It acknowledges the benefits of new technology and the opportunities it brings for mass participation and data manipulation. It focuses on the increase in interest in CS in recent years and draws on experience gained from the Open Air Laboratories (OPAL) programme launched in England in 2007. The drivers and objectives for OPAL are presented together with background information on the partnership, methods and scales. The approaches used by researchers ranged from direct public participation in mass data collection through field surveys to research with minimal public engagement. The supporting services focused on education, particularly to support participants new to science, a media strategy and data services. Examples from OPAL are used to illustrate the different approaches to the design and delivery of CS that have emerged over recent years and the breadth of opportunities for public participation the current landscape provides. Qualitative and quantitative data from OPAL are used as evidence of the impact of CS. While OPAL was conceived ahead of the more recent formalisation of approaches to the design, delivery and analysis of CS projects and their impact, it nevertheless provides a range of examples against which to assess the various benefits and challenges emerging in this fast developing field.

  10. CHARACTERISTICS AND SIGNIFICANCE OF OPALS IN PALYGORSKITE CLAY AT THE BOUNDARY BETWEEN JIANGSU AND ANHUI PROVINCES%苏皖坡缕石粘土中蛋白石特征及其成因意义

    Institute of Scientific and Technical Information of China (English)

    陈天虎; 徐晓春; Huifang Xu; 岳书仓

    2005-01-01

    TEM和XRD研究表明,在苏皖坡缕石粘土矿床的蛋白石坡缕石层中存在opal-A和opal-CT两种结构的蛋白石.蛋白石坡缕石层主要含坡缕石、opal-A、opal-CT,以及少量白云石和其它矿物,由富opal-A层和富opal-CT层互层组成,交互层的厚度在几个厘米左右.蛋白石坡缕石层中的矿物基本是自生矿物,从蒸发湖水中化学沉淀形成.矿物组成特征研究表明,蛋白石坡缕石层的矿物组分(Si、Mg、Al)来源于盆地周围玄武岩淋滤的浅层地下水.根据Opal-A和Opal-CT溶解度图解和坡缕石、白云石形成物理化学条件图解,当湖水具有高浓度溶解SiO2和Mg2+时,有利于opal-A和坡缕石形成,当湖水具有低浓度溶解SiO2时,有利于opal-CT结晶.因此,沉淀SiO2的结构状态取决于地下水补给的湖水溶解SiO2浓度.富opal-A和富opal-CT交互层的形成是古气候、古水文周期性变化的指示.富opal-CT层指示高地下水补给流入量,低蒸发量,湖水低盐度和溶解组分,代表湿润气候时期;而富opal-A层代表低地下水补给流入量,高蒸发量,高溶解组分浓度,代表干旱气候时期.

  11. Engineering three-dimensionally electrodeposited Si-on-Ni inverse opal structure for high volumetric capacity Li-ion microbattery anode.

    Science.gov (United States)

    Liu, Hao; Cho, Hyung-Man; Meng, Ying Shirley; Li, Quan

    2014-06-25

    Aiming at improving the volumetric capacity of nanostructured Li-ion battery anode, an electrodeposited Si-on-Ni inverse opal structure has been proposed in the present work. This type of electrode provides three-dimensional bi-continuous pathways for ion/electron transport and high surface area-to-volume ratios, and thus exhibits lower interfacial resistance, but higher effective Li ions diffusion coefficients, when compared to the Si-on-Ni nanocable array electrode of the same active material mass. As a result, improved volumetric capacities and rate capabilities have been demonstrated in the Si-on-Ni inverse opal anode. We also show that optimization of the volumetric capacities and the rate performance of the inverse opal electrode can be realized by manipulating the pore size of the Ni scaffold and the thickness of the Si deposit.

  12. Monolithic multiscale bilayer inverse opal electrodes for dye-sensitized solar cell applications.

    Science.gov (United States)

    Lee, Jung Woo; Moon, Jun Hyuk

    2015-03-12

    Multilayer structures in which the layers are both electrically and physically connected are critical to be used as high-performance electrodes for photovoltaic devices. We present the first multiscale bilayer inverse opal (IO) structures for application as electrodes in dye-sensitized solar cells (DSCs). A bilayer of a mesoscopic IO layer (70 nm pore diameter) and a top macroporous IO layer (215 nm and 250 nm pore diameters) was fabricated as the high-specific-area electrode and the light-harvesting enhancing layer, respectively. The mesoscopic IO layer exhibits a dye-adsorption density, which is approximately 4 times greater than that of the macroporous IO structure because of its small pore size. The macroporous IO layer exhibits a photonic bandgap reflection in the visible-light wavelength range. We incorporated the bilayer IO electrodes into DSCs and compared the effects of the pore sizes of the macroporous layers on the photocurrent densities of the DSCs. We observed that the bilayer IO electrode DSCs that contained a 250 nm IO layer exhibited photocurrent densities greater than those of 215 nm IO DSCs. This enhanced photocurrent density was achieved because the photonic bandgap (PBG) reflection wavelength matches the wavelength range in which the N719 dye has a small light-absorption coefficient. The fabrication of this structurally homogeneous IO bilayer allows a strong contact between the layers, and the resulting bilayer, therefore, exhibits a high photovoltaic performance. We believe that this bilayer structure provides an alternative approach to the development of optimized electrode structures for various devices.

  13. Oxygen Isotopes in Fresh Water Biogenic Opal: Northeastern US Alleroed-Younger Dryas Temperature Shift

    Science.gov (United States)

    Shemesh, Aldo; Peteet, Dorothy

    1997-01-01

    The first oxygen isotope analysis of biogenic opal from lake sediments, from the Allerod/Younger Dryas transition in a core from Linsley Pond, Connecticut, gives an average estimate of a 6 C drop in temperature during the Younger Dryas. This shift represents temperatures during the bloom season, and may be less than the winter temperature drop. The sharp transition itself, with a duration of about 200 years, suggests that the temperature decrease may have been as large as 12 C. Previous estimates of the Allerod/Younger Dryas temperature shifts are controversial, and range from 3-20 C, suggesting that further interdisciplinary research on the same samples is warranted. One way that global climate change manifests itself is by redistributing energy throughout the globe. The Northern Hemisphere latitudinal temperature gradient during the late-glacial is at present a controversial topic. The magnitude of air temperature shifts during the Allerod/Younger Dryas (YD) oscillation are estimated from mid-latitude pollen records surrounding the North Atlantic to be 3-5 C in Europe [Lowe et al., 19941 and 3-4 C in the eastern US [Peteet et al., 1993]. In contrast, lake temperatures estimates derived from aquatic midge larvae in the Canadian eastern maritimes and Maine range from 6-20 C, with larger shifts at more southern sites [Levesque et al., 1997]. The magnitude of YD cooling in Greenland ice cores ranges from at least 7 C from the Bolling warming [Dansgaard et al., 1989] to 15 C - a more recent estimate from borehole temperatures [Cuffey et al., 1995]. The ice core geochemical records reveal that massive frequent and short-term (decadal or less) changes in atmospheric composition occurred throughout this event, suggesting a very dynamic circulation [Mayewski et al., 1993).

  14. Passivation of ZnO Nanowire Guests and 3D Inverse Opal Host Photoanodes for Dye-Sensitized Solar Cells

    KAUST Repository

    Labouchere, Philippe

    2014-04-23

    A hierarchical host-guest nanostructured photoanode is reported for dye-sensitized solar cells. It is composed of ZnO nanowires grown in situ into the macropores of a 3D ZnO inverse opal structure, which acts both as a seed layer and as a conductive backbone host. Using a combination of self-assembly, hydrothermal or electrodeposition of single crystalline ZnO nanowires and TiO2 passivation, a novel photoanode with scattering capability for optimal light harvesting is fabricated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Acoustic and NMR investigations of melting and crystallization of indium-gallium alloys in pores of synthetic opal matrices

    Science.gov (United States)

    Pirozerskii, A. L.; Charnaya, E. V.; Lee, M. K.; Chang, L. J.; Nedbai, A. I.; Kumzerov, Yu. A.; Fokin, A. V.; Samoilovich, M. I.; Lebedeva, E. L.; Bugaev, A. S.

    2016-05-01

    The paper presents the results of studying the crystallization and melting processes of Ga-In eutectic alloys, which are embedded in opal matrices, using acoustic and NMR methods. The indium concentrations in the alloys were 4, 6, 9, and 15 at %. Measurements were performed upon cooling from room temperature to complete crystallization of the alloys and subsequent heating. It is revealed how the size effects and alloy composition influence the formation of phases with α- and β-Ga structures and on changes in the melting-temperature ranges. A difference was observed between the results obtained using acoustic and NMR methods, which was attributed to different temperature measurement conditions.

  16. Measurement of observables sensitive to coherence effects in hadronic Z decays with the OPAL detector at LEP

    CERN Document Server

    Fischer, Nadine; Kluth, Stefan; Plätzer, Simon; Skands, Peter

    2015-01-01

    A study of QCD coherence is presented based on a sample of about 397000 $e^+e^-$ hadronic annihilation events collected at $\\sqrt{s}=91$ GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions.

  17. Measurement of observables sensitive to coherence effects in hadronic Z decays with the OPAL detector at LEP

    Science.gov (United States)

    Fischer, N.; Gieseke, S.; Kluth, S.; Plätzer, S.; Skands, P.

    2015-12-01

    A study of QCD coherence is presented based on a sample of about 397,000 e+e- hadronic annihilation events collected at √{s}=91 GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions.

  18. Measurement of observables sensitive to coherence effects in hadronic Z decays with the OPAL detector at LEP

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, N. [Institute for Theoretical Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Monash University, School of Physics and Astronomy, Melbourne (Australia); Gieseke, S. [Institute for Theoretical Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Kluth, S. [Max-Planck-Institute for Physics, Munich (Germany); Plaetzer, S. [Durham University, Institute for Particle Physics Phenomenology, Durham (United Kingdom); University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Skands, P. [Monash University, School of Physics and Astronomy, Melbourne (Australia); Theoretical Physics, CERN, Geneva (Switzerland); Collaboration: OPAL Collaboration

    2015-12-15

    A study of QCD coherence is presented based on a sample of about 397,000 e{sup +}e{sup -} hadronic annihilation events collected at √(s) = 91 GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions. (orig.)

  19. Measurement of observables sensitive to coherence effects in hadronic Z decays with the OPAL detector at LEP

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, N., E-mail: nadine.fischer@monash.edu [Institute for Theoretical Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); School of Physics and Astronomy, Monash University, Melbourne (Australia); Gieseke, S. [Institute for Theoretical Physics, Karlsruhe Institute of Technology, Karlsruhe (Germany); Kluth, S. [Max-Planck-Institute for Physics, Munich (Germany); Plätzer, S. [Institute for Particle Physics Phenomenology, Durham University, Durham (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester (United Kingdom); Skands, P. [School of Physics and Astronomy, Monash University, Melbourne (Australia); Theoretical Physics, CERN, Geneva (Switzerland); Collaboration: OPAL Collaboration

    2015-11-30

    A study of QCD coherence is presented based on a sample of about 397,000 e{sup +}e{sup -} hadronic annihilation events collected at √s=91 GeV with the OPAL detector at LEP. The study is based on four recently proposed observables that are sensitive to coherence effects in the perturbative regime. The measurement of these observables is presented, along with a comparison with the predictions of different parton shower models. The models include both conventional parton shower models and dipole antenna models. Different ordering variables are used to investigate their influence on the predictions.

  20. Optically pumped distributed feedback dye lasing with slide-coated TiO₂ inverse-opal slab as Bragg reflector.

    Science.gov (United States)

    Han, Sung Gu; Lim, Jongchul; Shin, Jinsub; Lee, Sung-Min; Park, Taiho; Yoon, Jongseung; Woo, Kyoungja; Lee, Hyunjung; Lee, Wonmok

    2014-08-15

    We demonstrate an optical amplification of organic dye within a TiO2 inverse-opal (IO) distributed feedback (DFB) reflector prepared by a slide-coating method. Highly reflective TiO2 IO film was fabricated by slide coating the binary aqueous dispersions of polystyrene microspheres and charge-stabilized TiO2 nanoparticles on a glass slide and subsequently removing the polymer-opal template. TiO2 IO film was infiltrated, in turn, with the solutions of DCM, a fluorescent dye in various solvents with different indices of refraction. Optical pumping by frequency-doubled Nd:YAG laser resulted in amplified spontaneous emission in each dye solution. In accordance with the semi-empirical simulation by the FDTD method, DCM in ethanol showed the best emission/stopband matching for the TiO2 IO film used in this study. Therefore, photo excitation of a DCM/ethanol cavity showed a single-mode DFB lasing at 640 nm wavelength at moderate pump energy.

  1. Electrodeposited Structurally Stable V2O5 Inverse Opal Networks as High Performance Thin Film Lithium Batteries.

    Science.gov (United States)

    Armstrong, Eileen; McNulty, David; Geaney, Hugh; O'Dwyer, Colm

    2015-12-01

    High performance thin film lithium batteries using structurally stable electrodeposited V2O5 inverse opal (IO) networks as cathodes provide high capacity and outstanding cycling capability and also were demonstrated on transparent conducting oxide current collectors. The superior electrochemical performance of the inverse opal structures was evaluated through galvanostatic and potentiodynamic cycling, and the IO thin film battery offers increased capacity retention compared to micron-scale bulk particles from improved mechanical stability and electrical contact to stainless steel or transparent conducting current collectors from bottom-up electrodeposition growth. Li(+) is inserted into planar and IO structures at different potentials, and correlated to a preferential exposure of insertion sites of the IO network to the electrolyte. Additionally, potentiodynamic testing quantified the portion of the capacity stored as surface bound capacitive charge. Raman scattering and XRD characterization showed how the IO allows swelling into the pore volume rather than away from the current collector. V2O5 IO coin cells offer high initial capacities, but capacity fading can occur with limited electrolyte. Finally, we demonstrate that a V2O5 IO thin film battery prepared on a transparent conducting current collector with excess electrolyte exhibits high capacities (∼200 mAh g(-1)) and outstanding capacity retention and rate capability.

  2. Color-Coded Batteries - Electro-Photonic Inverse Opal Materials for Enhanced Electrochemical Energy Storage and Optically Encoded Diagnostics.

    Science.gov (United States)

    O'Dwyer, Colm

    2016-07-01

    For consumer electronic devices, long-life, stable, and reasonably fast charging Li-ion batteries with good stable capacities are a necessity. For exciting and important advances in the materials that drive innovations in electrochemical energy storage (EES), modular thin-film solar cells, and wearable, flexible technology of the future, real-time analysis and indication of battery performance and health is crucial. Here, developments in color-coded assessment of battery material performance and diagnostics are described, and a vision for using electro-photonic inverse opal materials and all-optical probes to assess, characterize, and monitor the processes non-destructively in real time are outlined. By structuring any cathode or anode material in the form of a photonic crystal or as a 3D macroporous inverse opal, color-coded "chameleon" battery-strip electrodes may provide an amenable way to distinguish the type of process, the voltage, material and chemical phase changes, remaining capacity, cycle health, and state of charge or discharge of either existing or new materials in Li-ion or emerging alternative battery types, simply by monitoring its color change.

  3. Current-induced suppression of superconductivity in a three-dimensional lattice of weakly linked indium grains in opal

    CERN Document Server

    Romanov, S G

    2000-01-01

    The current-voltage characteristics of the metal-dielectric composite have been investigated in the range of the resistive state near the superconducting transition temperature T/sub c/. The composite structure can be represented as a face-centered cubic lattice, which involves a large number of weakly linked indium nanograins and is stabilized in structural cavities of opal. The response to microwave radiation is used to characterize the resistive state of the composite. The comparative investigation into the current-voltage characteristics and the response of the composite to microwave radiation makes it possible to conclude that the weak links are superconducting in the region of the critical current (I/sub c/) of the composite as a whole. The transition of weak links to the resistive state occurs at currents immediately preceding the transition of the composite from the resistive state to the ohmic state. The model of the resistivity of the indium-opal composite is proposed on the basis of morphological e...

  4. A visual and organic vapor sensitive photonic crystal sensor consisting of polymer-infiltrated SiO2 inverse opal.

    Science.gov (United States)

    Zhang, Yuqi; Qiu, Jianhua; Hu, Rongrong; Li, Pei; Gao, Loujun; Heng, Liping; Tang, Ben Zhong; Jiang, Lei

    2015-04-21

    A photonic crystal (PC) sensor that can selectively detect organic vapors through visual color changes has been proposed. The sensor was fabricated by infiltrating a tetraphenylethene polymer (TPEP) into the voids of SiO2 inverse opal photonic crystal. When the sensor was exposed to tetrahydrofuran or acetone vapor, a red shift of the stopband of more than 50 nm could be clearly observed; meanwhile, the film's color changed from violet to cyan. Subsequently, when exposed to air, the stopband underwent a blue shift and the color returned to violet. The reason for the observed change is that a reversible adsorption-desorption process occurs on alternate exposure of the sensor to organic vapor and air, due to the high specific surface area of the inverse opal macroporous structure and the high affinity of TPEP to tetrahydrofuran and acetone. The adsorption of vapor analyte can increase the PC's effective refractive index, which will induce the stopband red shift and the resulting color change according to Bragg's Law. The reversible adsorption-desorption of organic vapors varied the effective refractive index of the sensor repeatedly, causing the reversible stopband shift and color change, and providing a general method for the design of visual vapor sensors.

  5. Atmospheric nitrogen oxides (NO and NO2) at Dome C, East Antarctica, during the OPALE campaign

    Science.gov (United States)

    Frey, M. M.; Roscoe, H. K.; Kukui, A.; Savarino, J.; France, J. L.; King, M. D.; Legrand, M.; Preunkert, S.

    2015-07-01

    Mixing ratios of the atmospheric nitrogen oxides NO and NO2 were measured as part of the OPALE (Oxidant Production in Antarctic Lands & Export) campaign at Dome C, East Antarctica (75.1° S, 123.3° E, 3233 m), during December 2011 to January 2012. Profiles of NOx mixing ratios of the lower 100 m of the atmosphere confirm that, in contrast to the South Pole, air chemistry at Dome C is strongly influenced by large diurnal cycles in solar irradiance and a sudden collapse of the atmospheric boundary layer in the early evening. Depth profiles of mixing ratios in firn air suggest that the upper snowpack at Dome C holds a significant reservoir of photolytically produced NO2 and is a sink of gas-phase ozone (O3). First-time observations of bromine oxide (BrO) at Dome C show that mixing ratios of BrO near the ground are low, certainly less than 5 pptv, with higher levels in the free troposphere. Assuming steady state, observed mixing ratios of BrO and RO2 radicals are too low to explain the large NO2 : NO ratios found in ambient air, possibly indicating the existence of an unknown process contributing to the atmospheric chemistry of reactive nitrogen above the Antarctic Plateau. During 2011-2012, NOx mixing ratios and flux were larger than in 2009-2010, consistent with also larger surface O3 mixing ratios resulting from increased net O3 production. Large NOx mixing ratios at Dome C arise from a combination of continuous sunlight, shallow mixing height and significant NOx emissions by surface snow (FNOx). During 23 December 2011-12 January 2012, median FNOx was twice that during the same period in 2009-2010 due to significantly larger atmospheric turbulence and a slightly stronger snowpack source. A tripling of FNOx in December 2011 was largely due to changes in snowpack source strength caused primarily by changes in NO3- concentrations in the snow skin layer, and only to a secondary order by decrease of total column O3 and associated increase in NO3- photolysis rates. A

  6. Coupling of titania inverse opals to nanocrystalline titania layers in dye-sensitized solar cells.

    Science.gov (United States)

    Lee, Seung-Hyun Anna; Abrams, Neal M; Hoertz, Paul G; Barber, Greg D; Halaoui, Lara I; Mallouk, Thomas E

    2008-11-20

    We report a quantitative comparison of the photoaction spectra, short circuit current densities, and power conversion efficiencies of dye-sensitized solar cells (DSSCs) that contain bilayers of nanocrystalline TiO2 (nc-TiO2) and titania inverse opal photonic crystals (PCs). Cells were fabricated with PC/nc-TiO2 and nc-TiO2/PC bilayer films on glass/tin oxide anode of the cell, as well as in a split configuration in which the nc-TiO2 and PC layers were deposited on the anode and cathode sides of the cell, respectively. Incident photon current efficiencies at single wavelengths and current-voltage curves in white light were obtained with both cathode and anode side illumination. The results obtained support a model proposed by Miguez and co-workers, in which coupling of the low refractive index PC layer to the higher index nc-TiO2 layer creates a standing wave in the nc-TiO2 layer, enhancing the response of the DSSC in the red region of the spectrum. This enhancement is very sensitive to the degree of physical contact between the two layers. A gap on the order of 200 nm thick, created by a polymer templating technique, is sufficient to decouple the two layers optically. The coupling of the nc-TiO2 and PC layers across the gap could be improved slightly by treatment with TiCl4 vapor. In the bilayer configuration, there is an enhancement in the IPCE across the visible spectrum, which is primarily caused by defect scattering in the PC layer. There is also an increase of 20-50 mV in the open circuit photovoltage of the cell. With anode side illumination, the addition of a PC layer to the nc-TiO2 layer increased the efficiency of DSSCs from 6.5 to 8.3% at a constant N719 dye loading of 155-160 nmol/cm2.

  7. High-performance characteristics of silicon inverse opal synthesized by the simple magnesium reduction as anodes for lithium-ion batteries

    Science.gov (United States)

    Jeong, Jae-Hun; Kim, Kwang-Hyun; Jung, Dong-Won; Kim, Ketack; Lee, Sung-Man; Oh, Eun-Suok

    2015-12-01

    Inverse silicon opal (ISi) and carbon-coated inverse Si opal (C-ISi) structures are prepared from the simple thermal reduction method using magnesium and investigated as the anode materials in lithium-ion batteries. The ISi and C-ISi samples comprise continuously arranged inverse opal structures, constructed by Si nanoparticles. The macroporous structures in ∼1 μm range are favourable for lithium-ion transport and more importantly for absorbing volumetric change in the silicon nanoparticles. Moreover, the carbon coating on the inverse Si opal improves the electrical conductivity and acts as a mechanical buffer for the volume change. C-ISi sample shows a high capacity of 1550 mAh g-1 at the 100th cycle with very stable cycle retention, whereas the ISi and pristine Si samples show 1146.4 mAh g-1 and approximately zero, respectively, at the 100th cycle with rapid capacity fading. Surprisingly, the volumetric expansion of C-ISi electrode after 100th cycles is only 16.1%, which is as low as that for commercial graphite electrodes.

  8. Structural and magnetic properties of inverse opal photonic crystals studied by x-ray diffraction, scanning electron microscopy, and small-angle neutron scattering

    NARCIS (Netherlands)

    Grigoriev, S.V.; Napolskii, K.S.; Grigoryeva, N.A.; Vasilieva, A.V.; Mistonov, A.A.; Chernyshov, D.Y.; Petukhov, A.V.; Belov, D.V.; Eliseev, A.A.; Lukashin, A.V.; Tretyakov, Y.D.; Sinitskii, A.S.; Eckerlebe, H.

    2009-01-01

    The structural and magnetic properties of nickel inverse opal photonic crystal have been studied by complementary experimental techniques, including scanning electron microscopy, wide-angle and small-angle diffraction of synchrotron radiation, and polarized neutrons. The sample was fabricated by ele

  9. Expression of the outcome predictor in acute leukemia 1 (OPAL1) gene is not an independent prognostic factor in patients treated according to COALL or St Jude protocols

    NARCIS (Netherlands)

    A. Holleman (Amy); C.H. Pui (Ching-Hon); W.E. Evans (William); R. Pieters (Rob); M.L. den Boer (Monique); M.H. Cheok (Meyling); K.M. Kazemier (Karin); D. Pei (Deqing); J.R. Downing (James); G.E. Janka-Schaub (Gritta); U. Göbel (Ulrich); U. Graubner (Ulrike)

    2006-01-01

    textabstractNew prognostic factors may result in better risk classification and improved treatment of children with acute lymphoblastic leukemia (ALL). Recently, high expression of a gene named OPAL1 (outcome predictor in acute leukemia) was reported to be associated with favorable prognosis in ALL.

  10. Coupling of Ag Nanoparticle with Inverse Opal Photonic Crystals as a Novel Strategy for Upconversion Emission Enhancement of NaYF4: Yb(3+), Er(3+) Nanoparticles.

    Science.gov (United States)

    Shao, Bo; Yang, Zhengwen; Wang, Yida; Li, Jun; Yang, Jianzhi; Qiu, Jianbei; Song, Zhiguo

    2015-11-18

    Rare-earth-ion-doped upconversion (UC) nanoparticles have generated considerable interest because of their potential application in solar cells, biological labeling, therapeutics, and imaging. However, the applications of UC nanoparticles were still limited because of their low emission efficiency. Photonic crystals and noble metal nanoparticles are applied extensively to enhance the UC emission of rare earth ions. In the present work, a novel substrate consisting of inverse opal photonic crystals and Ag nanoparticles was prepared by the template-assisted method, which was used to enhance the UC emission of NaYF4: Yb(3+), Er(3+) nanoparticles. The red or green UC emissions of NaYF4: Yb(3+), Er(3+) nanoparticles were selectively enhanced on the inverse opal substrates because of the Bragg reflection of the photonic band gap. Additionally, the UC emission enhancement of NaYF4: Yb(3+), Er(3+) nanoparticles induced by the coupling of metal nanoparticle plasmons and photonic crystal effects was realized on the Ag nanoparticles included in the inverse opal substrate. The present results demonstrated that coupling of Ag nanoparticle with inverse opal photonic crystals provides a useful strategy to enhance UC emission of rare-earth-ion-doped nanoparticles.

  11. Light and Small-Angle X-Ray Diffraction from Opal-Like Structures: Transition from Two- to Three-Dimensional Regimes and Effects of Disorder

    NARCIS (Netherlands)

    Samusev, A.K.; Samusev, K.B.; Sinev, I.S.; Rybin, M.V.; Limonov, M.F.; Grigoryeva, N.A.; Grigoryeva, S.V.; Petukhov, A.V.|info:eu-repo/dai/nl/304829196

    2012-01-01

    Conclusions To summarize, in this chapter diffraction of light and x-rays on opal-like structures is considered. New methodological approaches to collection, processing, and interpretation of experimental data are presented. In particular, a novel representation of the light diffraction data in the

  12. Light and Small-Angle X-Ray Diffraction from Opal-Like Structures: Transition from Two- to Three-Dimensional Regimes and Effects of Disorder

    NARCIS (Netherlands)

    Samusev, A.K.; Samusev, K.B.; Sinev, I.S.; Rybin, M.V.; Limonov, M.F.; Grigoryeva, N.A.; Grigoryeva, S.V.; Petukhov, A.V.

    2012-01-01

    Conclusions To summarize, in this chapter diffraction of light and x-rays on opal-like structures is considered. New methodological approaches to collection, processing, and interpretation of experimental data are presented. In particular, a novel representation of the light diffraction data in the

  13. Fabrication and Characterization of SnO2 Inverse opal Materials%SnO2反opal光子晶体的制备及表征

    Institute of Scientific and Technical Information of China (English)

    代超; 王爱军; 陈胜利; 袁桂梅

    2012-01-01

    SnO2 inverse opal thin films were fabricated by filling opal films of polystyrene (PS) spheres with SnO2 and then removing the PS spheres through calcining at 450°C. The filling process of opal films was accomplished by the dip-drawing method and Sol-LPD method. The quality of photonic crystal samples were assessed by SEM and UV-Vis spectrophotometer. It is found that the obtained SnO2 inverse opals displayed the three-dimensional ordered structure. Brag reflection peaks of the SnO2 inverse opal films prepared by Sol-LPD method is red-shifted, in compared to that prepared by dip-drawing method of the same PS template, indicating that the filling rate of SnO2 inverse opal films prepared by Sol-LPD method was higher than that prepared by dipping drawing method SnO2 heterostruc-ture inverse opal film were fabricated by Sol-LPD filling method.%以PS opal膜为模板制得了SnO2反opal光子晶体膜.采用浸渍提拉法和Sol-LPD法对PS opal模板进行填充,450℃焙烧除去PS模极得到SnO2反opal光子晶体.SEM和UV-Vis透射表征显示,两种填充方式都能得到三维有序的SnO2反opal光子晶体;以相同的PS opal膜为模板,通过Sol-LPI填充法得到的SnO2反opal膜的禁带位置向长波移动(以浸渍提拉法制得的光子晶体的禁带位置为基准).这证实Sol-LPD填充法比浸渍提拉法有更高的填充率.通过Sol-LPD填充法还能够制备具有多重禁带的SnO2反opal异质复合膜.

  14. Biogenic CaCO3 and Opal Depositions and Their Latitudinal Comparison During the Past 600 ka in the Central Equatorial Pacific

    Directory of Open Access Journals (Sweden)

    Boo-Keun Khim

    2015-01-01

    Full Text Available The orbital-scale variations in biogenic CaCO3 and opal abundance in two piston cores collected in the central equatorial Pacific (core PC5101 from a southern site at _ and core PC5103 from a northern site at _ were compared to assess latitudinal differences. The correlation between the oxygen isotope stratigraphy of planktonic foraminifera (Globigerinoides sacculifer of PC5103 with the LR04 stacks provides the age of PC5103 to be approximately 950 ka. The age of PC5103 was further refined by correlating the CaCO3 content with the well-dated core RC11-210. The age of PC5101 was also constrained by the same CaCO3 chronostratigraphic correlation with RC11-210, resulting in an age of approximately 650 ka. Distinct orbital-scale series of CaCO3 and opal variations appear to be parallel between the two cores during the past 600 ka, which are controlled mainly by eccentricity with an approximate periodicity of 100 ka. It is worth noting that the biogenic CaCO3 and opal deposition patterns in the two cores differ between interglacial and glacial periods. During interglacial periods the biogenic opal content is higher in the southern core than in the northern core, which corresponds with the present-day condition. In contrast the CaCO3 content is higher in the northern core, which is contradictory to the present-day northward decreasing CaCO3 deposition pattern from the Equator. The collection site of PC5101 is approximately 350 m deeper than that of PC5103, which significantly promotes CaCO3 dissolution and causes unexpectedly high CaCO3 content at the northern site in contrast to the biogenic opal content.

  15. LEP1 measurement of heavy quark forward-backward asymmetries with Opal detector; Mesure de l`asymetrie avant-arriere des quarks lourds a LEP1 avec le detecteur Opal

    Energy Technology Data Exchange (ETDEWEB)

    Lafoux, H.

    1996-04-30

    Using all data collected by OPAL during the first phase of LEP operation, called LEP1, we have measured the b and c quark forward-backward asymmetries on and around the Z{sup 0} peak. The measurement, which is based on prompt leptons produced in semileptonic decays of heavy quarks, has been optimized using artificial neural networks whenever necessary, that is whenever the problem to solve implied taking into account simultaneously a large number of parameters. Our results are compatible with other LEP measurements and with the Standard Model predictions for a top quark of 174{+-}31 GeV/c{open_square} and a Higgs boson mass between 60 and 1000 GeV/c{open_square}. (author). 159 refs., 88 figs., 37 tabs.

  16. Enhancement of second harmonic generation in NaNO{sub 2}-infiltrated opal photonic crystal using structural light focusing

    Energy Technology Data Exchange (ETDEWEB)

    Zaytsev, Kirill I., E-mail: kirzay@gmail.com; Yurchenko, Stanislav O., E-mail: st.yurchenko@mail.ru [Bauman Moscow State Technical University, 105005, 2nd Baumanskaya str. 5, Moscow (Russian Federation)

    2014-08-04

    Experimental and numerical results for second harmonic generation (SHG) in photonic crystal (PC) based on NaNO{sub 2}-infiltrated opal matrix are presented. SHG is performed in reflection mode; thus, the direction of the SHG maximum is equal to the angle of mirror reflection. The PC was pumped with femtosecond optical pulses at different angles of incidence, allowing the dependence of the SHG efficiency on the location of the fundamental wavelength toward the PC band gap (BG) to be examined. The most efficient SHG was observed when pumping the BG of the PC. To interpret the experimental results, finite-difference time-domain numerical simulations of the light interaction with the PC were conducted. The observed effect of highly efficient SHG is associated with structural light focusing, and, as a consequence, with strong optical field localization within certain near-surface PC regions. Thus, SHG enhancement based on structural light focusing in PC was demonstrated.

  17. Reflection Band Control of Inverse Opal Film with Photoresponse Properties of Push-Pull Type Azobenzene LC Polymers

    Directory of Open Access Journals (Sweden)

    Sunnam Kim

    2008-01-01

    Full Text Available DcAz2Mc and DR1Mc molecules having push-pull type of azobenzene groups are synthesized, and their photo-orientational behaviors are investigated in the polymer system. In order to understand the relationship between a molecular structure and its physical properties, electronic structure calculation is computationally carried out. Regarding to their photo response properties, the copolymers of poly(DcAz2Mc-co-M6PBMe and poly(DR1Mc-co-M6PBMe are infiltrated into inverse opal films, and Bragg reflection shifts are observed under photostimuli. When the linearly polarized light is irradiated, Bragg reflection bands are shifted to the longer wavelength region as reflective index increases.

  18. Creating bio-inspired hierarchical 3D-2D photonic stacks via planar lithography on self-assembled inverse opals

    CERN Document Server

    Burgess, Ian B; Loncar, Marko

    2012-01-01

    Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.

  19. Creating bio-inspired hierarchical 3D-2D photonic stacks via planar lithography on self-assembled inverse opals.

    Science.gov (United States)

    Burgess, Ian B; Aizenberg, Joanna; Lončar, Marko

    2013-12-01

    Structural hierarchy and complex 3D architecture are characteristics of biological photonic designs that are challenging to reproduce in synthetic materials. Top-down lithography allows for designer patterning of arbitrary shapes, but is largely restricted to planar 2D structures. Self-assembly techniques facilitate easy fabrication of 3D photonic crystals, but controllable defect-integration is difficult. In this paper we combine the advantages of top-down and bottom-up fabrication, developing two techniques to deposit 2D-lithographically-patterned planar layers on top of or in between inverse-opal 3D photonic crystals and creating hierarchical structures that resemble the architecture of the bright green wing scales of the butterfly, Parides sesostris. These fabrication procedures, combining advantages of both top-down and bottom-up fabrication, may prove useful in the development of omnidirectional coloration elements and 3D-2D photonic crystal devices.

  20. Enhancement of second harmonic generation in NaNO2-infiltrated opal photonic crystal using structural light focusing

    Science.gov (United States)

    Zaytsev, Kirill I.; Yurchenko, Stanislav O.

    2014-08-01

    Experimental and numerical results for second harmonic generation (SHG) in photonic crystal (PC) based on NaNO2-infiltrated opal matrix are presented. SHG is performed in reflection mode; thus, the direction of the SHG maximum is equal to the angle of mirror reflection. The PC was pumped with femtosecond optical pulses at different angles of incidence, allowing the dependence of the SHG efficiency on the location of the fundamental wavelength toward the PC band gap (BG) to be examined. The most efficient SHG was observed when pumping the BG of the PC. To interpret the experimental results, finite-difference time-domain numerical simulations of the light interaction with the PC were conducted. The observed effect of highly efficient SHG is associated with structural light focusing, and, as a consequence, with strong optical field localization within certain near-surface PC regions. Thus, SHG enhancement based on structural light focusing in PC was demonstrated.

  1. Search for Dirac Magnetic Monopoles in $e^{+}e^{-}$ Collisions with the OPAL Detector at LEP2

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, K.W.; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, R.M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Cozzi, M.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.M.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, J.W.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, M.; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay Jr., A.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, P.; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, N.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, D.E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, M.; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, D.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2008-01-01

    This letter describes a direct search for pair produced magnetic monopoles in e+e- collisions. The analysis is based on 62.7 pb^-1 of data collected with the OPAL detector at an average centre-of-mass energy of sqrt(s)= 206.3GeV. The monopole signal was assumed to be characterized by two back-to-back particles with an anomalously high ionization energy loss de/dx in the tracking chambers. No evidence for production of monopoles was observed. Upper limits were obtained on the magnetic monopole pair-production cross-section (sigma) in the mass range 45 GeV/c^2

  2. Study of prompt photon and neutral pion production in photon-photon scattering with the OPAL experiment

    CERN Document Server

    Lillich, Joachim

    2003-01-01

    For the first time at LEP the production of prompt photons is studied in the collisions of quasi-real photons using the OPAL data taken at e+e- centre-of mass energies between 183 GeV and 209 GeV. The total inclusive production cross-section for isolated prompt photons in the kinematic range of transverse momentum > 3.0 GeV and the absolut value of pseudorapidity <1 is determined to be (0.32 +- 0.04 (stat) +- 0.04 (sys)) pb. Differential cross-sections are compared to the predictions of a next-to-leading-order (NLO) calculation. In the second part of this thesis inclusive differential neutral pion cross-sections in photon photon collisons are measured. This measurement is an important test of QCD. In addition this process is the main background for prompt photons.

  3. Slow light enhanced near infrared luminescence in CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} inverse opal photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhengwen, E-mail: yangzw@kmust.edu.cn; Wu, Hangjun; Li, Jun; Shao, Bo; Qiu, Jianbei; Song, Zhiguo

    2015-08-25

    Highlights: • CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} photonic crystals was prepared. • Near infrared emission in the CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} inverse opal was obtained. • Near infrared emission was enhanced by slow light effect of photonic crystals. - Abstract: The surface plasmon resonances of metal nanoparticles and energy transfer between rare earth ions were used widely to enhance the near infrared emission of rare earth ions. In this paper, a new method for near infrared emission enhancement of rare-earth is reported. The CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} inverse opals with the photonic band gaps at the 500 and 450 nm were prepared by using polystyrene colloidal crystal as templates, and their near infrared emission properties were investigated. The results show that the near infrared emission property of the CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} inverse opals depends on the overlapped extend between the excited light and photonic band gap. The near infrared emission located at the 1540 nm of the CeO{sub 2}: Er{sup 3+}, Yb{sup 3+} inverse opals have been enhanced obviously when the wavelength of the excitation light overlapped with photonic band gaps edge, which is attributed to the slow light effect of photonic crystals. The enhancement of near infrared emission may be important for the development of infrared laser and amplifiers for optical communication.

  4. Measurements of jet rates with the anti-$k_T$ and SiScone algorithms at LEP with the OPAL detector

    CERN Document Server

    Verbytskyi, A

    2016-01-01

    We study jet production in $e^+e^−$ annihilation to hadrons with data recorded by the OPAL experiment at LEP at centre-of-mass energies between 90 GeV and 207 GeV. The jet $e^+e^−$ production rates were measured for the first time with the anti-$k_T$ and SiScone jet clustering algorithms. We compare the data with predictions by modern Monte Carlo event generators.

  5. Real-time Simulation of Cyber-physical Power System Based on OPAL-RT and OPNET%基于OPAL-RT和OPNET的电力信息物理系统实时仿真

    Institute of Scientific and Technical Information of China (English)

    汤奕; 王琦; 邰伟; 陈彬; 倪明

    2016-01-01

    With the development of smart grid technology,the observability and controllability of power cyber-physical system (CPS) are greatly enhanced.The procedures of information collection,transmission and processing have more influences on power system services.The construction of dynamic co-simulation platform for power CPS will provide technical support for the researches of related theories and applications.The existing simulation schemes and their structures are analyzed.The essential difference between mathematical models of power flow and information flow makes it necessary to build a real-time co-simulation platform.Based on the power system simulation tool OPAL-RT and the communication simulation tool OPNET, a real-time simulation platform for power CPS is proposed with the originally developed data transmission interface and conversion module,which can precisely simulate the dynamic characteristics of power system with a high speed.A case study of load control system shows the reasonability and validity of the platform.%随着智能电网建设的推进,电力信息物理系统(CPS)的可观性和可控性得到了极大增强。电力CPS的信息采集、传输、处理等过程对电力业务的影响越发明显。建立电力 CPS的动态联合仿真平台有助于为相关理论和应用研究提供坚实的技术支撑。文中对比分析了现有的联合仿真平台方案与架构,指出由于电力流和信息流在数学模型上的本质区别,需要建立实时联合仿真平台;基于电力仿真工具 OPAL-RT和通信仿真工具 OPNET,研制开发了数据交互接口及数据转换模块,建立了电力CPS 实时仿真平台,能够高速、精确地模拟电力 CPS 动态响应特性。针对电力CPS负荷控制的仿真算例结果表明,所研制的电力CPS实时仿真平台具有合理性和有效性。

  6. Energy transfer and visible-infrared quantum cutting photoluminescence modification in Tm-Yb codoped YPO(4) inverse opal photonic crystals.

    Science.gov (United States)

    Wang, Siqin; Qiu, Jianbei; Wang, Qi; Zhou, Dacheng; Yang, Zhengwen

    2015-08-01

    YPO4:  Tm, Yb inverse opal photonic crystals were successfully synthesized by the colloidal crystal templates method, and the visible-infrared quantum cutting (QC) photoluminescence properties of YPO4:  Tm, Yb inverse opal photonic crystals were investigated. We obtained tetragonal phase YPO4 in all the samples when the samples sintered at 950°C for 5 h. The visible emission intensity of Tm3+ decreased significantly when the photonic bandgap was located at 650 nm under 480 nm excitation. On the contrary, the QC emission intensity of Yb3+ was enhanced as compared with the no photonic bandgap sample. When the photonic bandgap was located at 480 nm, the Yb3+ and Tm3+ light-emitting intensity weakened at the same time. We demonstrated that the energy transfer between Tm3+ and Yb3+ is enhanced by the suppression of the red emission of Tm3+. Additionally, the mechanisms for the influence of the photonic bandgap on the energy transfer process of the Tm3+, Yb3+ codoped YPO4 inverse opal are discussed.

  7. Paleoproductivity and paleoceanography of the last 4.3 Myrs at IODP Expedition 323 Site U1341 in the Bering Sea based on biogenic opal content

    Science.gov (United States)

    Iwasaki, Shinya; Takahashi, Kozo; Kanematsu, Yoshiyuki; Asahi, Hirofumi; Onodera, Jonaotaro; Ravelo, A. C.

    2016-03-01

    Site U1341 in the southern Bering Sea was drilled and cored down to 600 meters below sea-floor (mbsf) during Integrated Ocean Drilling Program (IODP) Expedition 323, covering a nearly complete record of the last 4.3 million years (Myrs). Analyses of the biogenic opal content of sediments at the site provide detailed and useful information on past biological productivity and paleoceanographic changes that occurred in the region including shifts in the oceanographic condition during the intensification of the Northern Hemisphere Glaciation (NHG) and the Mid-Pleistocene Transition (MPT). An overall decreasing trend in the %biogenic opal record, combined with evidence from microfossil assemblages, indicates a gradual shift in environmental conditions during the last 4.3 Myrs, from warm and nutrient-rich conditions to cool conditions with sea-ice. On the other hand, biogenic opal mass accumulation rates (MAR) were high during 2.6-2.1 Ma after the intensification of the NHG, unlike in the western North Pacific. High biological productivity during this specific interval is consistent with the results of previous studies in the other Marginal Seas, possibly suggesting that iron leakage from the Bering Continental Shelf occurred. After the MPT, the data suggest that there was sea-ice expansion and discharge of lithogenic matter during glacial periods, and high productivity during interglacial periods.

  8. The effect of particle size, morphology and C-rates on 3D structured Co3O4 inverse opal conversion mode anode materials

    Science.gov (United States)

    McNulty, David; Geaney, Hugh; Carroll, Elaine; Garvey, Shane; Lonergan, Alex; O’Dwyer, Colm

    2017-02-01

    Engineering Co3O4 nanoparticles into highly ordered, 3D inverse opal (IO) structures is shown to significantly improve their performance as more efficient conversion mode Li-ion anode materials. By comparison with Co3O4 microparticles, the advantages of the porous anode architecture are clearly shown. The inverse opal material markedly enhances specific capacity and capacity retention. The impact of various C rates on the rate of the initial charge demonstrates that higher rate charging (10 C) was much less destructive to the inverse opal structure than charging at a slow rate (0.1 C). Slower C rates that affect the IO structure resulted in higher specific capacities (more Li2O) as well as improved capacity retention. The IO structures cycle as CoO, which improves Coulombic efficiency and limits volumetric changes, allowing rate changes more efficiently. This work demonstrates how 3D IOs improve conversion mode anode material performance in the absence of additive or binders, thus enhancing mass transport of Li2O charge–discharge product through the open structure. This effect mitigates clogging by structural changes at slow rates (high capacity) and is beneficial to the overall electrochemical performance.

  9. CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor.

    Science.gov (United States)

    Xia, Lei; Xu, Lin; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; Song, Hongwei

    2015-06-04

    The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I-t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution TEM (HRTEM), Energy-dispersive X-ray analysis (EDX) and X-ray diffraction pattern (XRD). The result indicated that the structure of IOPCs and loading of CdS QDs could greatly improve the electrochemical properties. Three SILAR cycles of CdS QDs sensitization was the optimum condition for preparing electrodes, it exhibited a sensitivity of 4345 μA mM(-1) cm(-2) to glucose with a 0.15 μM detection limit (S/N= 3) and a linear range from 0.15 μM to 0.5 mM under a working potential of +0.7 V. It also showed strong stability, good reproducibility, excellent selectivity and fast amperometric response. This work provides a promising approach for realizing excellent photoelectrochemical nonenzymatic glucose biosensor of similar composite structure.

  10. CdS quantum dots modified CuO inverse opal electrodes for ultrasensitive electrochemical and photoelectrochemical biosensor

    Science.gov (United States)

    Xia, Lei; Xu, Lin; Song, Jian; Xu, Ru; Liu, Dali; Dong, Biao; Song, Hongwei

    2015-01-01

    The CuO inverse opal photonic crystals (IOPCs) were synthesized by the sol-gel method and modified with CdS quantum dots by successive ionic layer adsorption and reaction (SILAR). CdS QDs modified CuO IOPCs FTO electrodes of different SILAR cycles were fabricated and their electrochemical properties were studied by cyclic voltammetry (CV) and chronoamperometry (I–t). Structure and morphology of the samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution TEM (HRTEM), Energy-dispersive X-ray analysis (EDX) and X-ray diffraction pattern (XRD). The result indicated that the structure of IOPCs and loading of CdS QDs could greatly improve the electrochemical properties. Three SILAR cycles of CdS QDs sensitization was the optimum condition for preparing electrodes, it exhibited a sensitivity of 4345 μA mM-1 cm-2 to glucose with a 0.15 μM detection limit (S/N= 3) and a linear range from 0.15 μM to 0.5 mM under a working potential of +0.7 V. It also showed strong stability, good reproducibility, excellent selectivity and fast amperometric response. This work provides a promising approach for realizing excellent photoelectrochemical nonenzymatic glucose biosensor of similar composite structure. PMID:26042520

  11. Molecular imprinted opal closest-packing photonic crystals for the detection of trace 17β-estradiol in aqueous solution.

    Science.gov (United States)

    Sai, Na; Wu, Yuntang; Sun, Zhong; Huang, Guowei; Gao, Zhixian

    2015-11-01

    A novel opal closest-packing (OCP) photonic crystal (PC) was prepared by the introduction of molecular imprinting technique into the OCP PC. This molecular imprinted (MI)-OCP PC was fabricated via a vertical convective self-assembly method using 17β-estradiol (E2) as template molecules for monitoring E2 in aqueous solution. Morphology characterization showed that the MI-OCP PC possessed a highly ordered three-dimensional (3D) periodically-ordered structure, showing the desired structural color. The proposed PC material displayed a reduced reflection intensity when detecting E2 in water environment, because the molecular imprinting recognition events make the optical characteristics of PC change. The Bragg diffraction intensity decreased by 19.864 a.u. with the increase of E2 concentration from 1.5 ng mL(-1) to 364.5 ng mL(-1) within 6 min, whereas there were no obvious peak intensity changes for estriol, estrone, cholesterol, testosterone and diethylstilbestrol, indicating that the MI-OCP PC had selective and rapid response for E2 molecules. The adsorption results showed that the OCP structure and homogeneous layers were created in the MI-OCP PC with higher adsorption capacity. Thus, it was learned the MI-OCP PC is a simple prepared, sensitive, selective, and easy operative material, which shows promising use in routine supervision for residue detection in food and environment.

  12. Nanocasting hierarchical carbide-derived carbons in nanostructured opal assemblies for high-performance cathodes in lithium-sulfur batteries.

    Science.gov (United States)

    Hoffmann, Claudia; Thieme, Sören; Brückner, Jan; Oschatz, Martin; Biemelt, Tim; Mondin, Giovanni; Althues, Holger; Kaskel, Stefan

    2014-12-23

    Silica nanospheres are used as templates for the generation of carbide-derived carbons with monodisperse spherical mesopores (d=20-40 nm) and microporous walls. The nanocasting approach with a polycarbosilane precursor and subsequent pyrolysis, followed by silica template removal and chlorine treatment, results in carbide-derived carbons DUT-86 (DUT=Dresden University of Technology) with remarkable textural characteristics, monodisperse, spherical mesopores tunable in diameter, and very high pore volumes up to 5.0 cm3 g(-1). Morphology replication allows these nanopores to be arranged in a nanostructured inverse opal-like structure. Specific surface areas are very high (2450 m2 g(-1)) due to the simultaneous presence of micropores. Testing DUT-86 samples as cathode materials in Li-S batteries reveals excellent performance, and tailoring of the pore size allows optimization of cell performance, especially the active center accessibility and sulfur utilization. The outstanding pore volumes allow sulfur loadings of 80 wt %, a value seldom achieved in composite cathodes, and initial capacities of 1165 mAh gsulfur(-1) are reached. After 100 cycle capacities of 860 mAh gsulfur(-1) are retained, rendering DUT-86 a high-performance sulfur host material.

  13. Investigation of hidden periodic structures on SEM images of opal-like materials using FFT and IFFT.

    Science.gov (United States)

    Stephant, Nicolas; Rondeau, Benjamin; Gauthier, Jean-Pierre; Cody, Jason A; Fritsch, Emmanuel

    2014-01-01

    We have developed a method to use fast Fourier transformation (FFT) and inverse fast Fourier transformation (IFFT) to investigate hidden periodic structures on SEM images. We focused on samples of natural, play-of-color opals that diffract visible light and hence are periodically structured. Conventional sample preparation by hydrofluoric acid etch was not used; untreated, freshly broken surfaces were examined at low magnification relative to the expected period of the structural features, and, the SEM was adjusted to get a very high number of pixels in the images. These SEM images were treated by software to calculate autocorrelation, FFT, and IFFT. We present how we adjusted SEM acquisition parameters for best results. We first applied our procedure on an SEM image on which the structure was obvious. Then, we applied the same procedure on a sample that must contain a periodic structure because it diffracts visible light, but on which no structure was visible on the SEM image. In both cases, we obtained clearly periodic patterns that allowed measurements of structural parameters. We also investigated how the irregularly broken surface interfered with the periodic structure to produce additional periodicity. We tested the limits of our methodology with the help of simulated images.

  14. Enhanced rare earth photoluminescence in inverse opal photonic crystals and its application for pH sensing

    Science.gov (United States)

    Zhu, Yongsheng; Cui, Shaobo; Wang, Yinhua; Liu, Mao; Lu, Cheng; Mishra, Abhinay; Xu, Wen

    2016-10-01

    Concentration quenching effects of identical rare earth (RE) activator ions and energy transfer (ET) between different RE ions often compromise the photoluminescence (PL) quantum efficiency in RE based luminescence materials. Here, we demonstrate that in NaGd(WO4)2:Tb3+, Eu3+ inverse opal photonic crystals (IOPCs), the suppression of the emission line located in the photonic stop band (PSB) and a dramatic increase of the lifetimes of Eu3+ and Tb3+ ions are observed. More interestingly, the concentration quenching among Eu3+ ions and ET from Tb3+ to Eu3+ is significantly relieved owing to the periodic empty cavity structure of IOPCs. As a consequence, the luminescent quantum efficiency (QE) of the NaGd(WO4)2:Tb3+, Eu3+ IOPCs increases ˜2 times more than that of crushed NaGd(WO4)2:Tb3+, Eu3+ powder. In addition, a reusable pH sensor with good linear response (pH 5-10) has been designed based on the high surface-to-volume ratio, high connectivity, and enhanced luminescence of NaGd(WO4)2:Tb3+, Eu3+IOPCs, which could be applied to the dynamical detection of pH value.

  15. Measurement of the running of the QED coupling in small angle Bhabha scattering with the OPAL detector

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, P.

    2005-06-01

    Using the high precision OPAL Silicon-Tungsten luminometer at LEP, the running of the effective QED coupling {alpha}(t) is measured for space-like momentum transfer 1.81 {<=} -t {<=} 6.07 GeV{sup 2} through its effect on the angular spectrum of small angle Bhabha scattering. In an almost ideal QED framework, with very favourable experimental conditions, we obtain a strong direct evidence that the running of {alpha}(t) is consistent with standard model expectations. The null hypothesis that {alpha} remains constant within the above interval of -t is excluded with a significance above 5{sigma}: {delta}{alpha}(-6.07 GeV{sup 2}) - {delta}{alpha}(-1.81 GeV{sup 2}) = 0.00450 {+-} 0.00079 The hadronic contribution to the running of the coupling has been estimated to be: {delta}{alpha}{sub had}(-6.07 GeV{sup 2}) - {delta}{alpha}{sub had}(-1.81 GeV{sup 2}) = 0.00248 {+-} 0.00079. This result is inconsistent at the level of more than 3{sigma} with the hypothesis that only leptonic loops contribute to the running, and therefore provide the first clear space-like experimental evidence that hadronic loops also contribute. (orig.)

  16. Anatomy of biologically mediated opal speleothems in the World's largest sandstone cave: Cueva Charles Brewer, Chimantá Plateau, Venezuela

    Science.gov (United States)

    Aubrecht, R.; Brewer-Carías, Ch.; Šmída, B.; Audy, M.; Kováčik, Ľ.

    2008-01-01

    Siliceous speleothems can be formed in sandstone caves. Recently, opal "biospeleothems" have been found in the World's largest cave in Precambrian sandstones on the Chimantá Tepui in Venezuela. The speleothems, although reminiscent of normal stalactites and stalagmites from limestone caves, are in fact large microbialites. More than a dozen forms were distinguished, but they share a common structure and origin. They consist of two main types: 1. fine-laminated columnar stromatolite formed by silicified filamentous microbes (either heterotrophic filamentous bacteria or cyanobacteria) and 2. a porous peloidal stromatolite formed by Nostoc-type cyanobacteria. The first type usually forms the central part and the second type, the outer part, of speleothems. Fungal hyphae, metazoan and plant remains also subordinately contribute to speleothem construction. The speleothems occur out of the reach of flowing water; the main source of silica is the condensed cave moisture which is the main dissolution-reprecipitation agent. Speleothems which originated by encrustation of spider threads are unique.

  17. Facile control of silica nanoparticles using a novel solvent varying method for the fabrication of artificial opal photonic crystals

    Science.gov (United States)

    Gao, Weihong; Rigout, Muriel; Owens, Huw

    2016-12-01

    In this work, the Stöber process was applied to produce uniform silica nanoparticles (SNPs) in the meso-scale size range. The novel aspect of this work was to control the produced silica particle size by only varying the volume of the solvent ethanol used, whilst fixing the other reaction conditions. Using this one-step Stöber-based solvent varying (SV) method, seven batches of SNPs with target diameters ranging from 70 to 400 nm were repeatedly reproduced, and the size distribution in terms of the polydispersity index (PDI) was well maintained (within 0.1). An exponential equation was used to fit the relationship between the particle diameter and ethanol volume. This equation allows the prediction of the amount of ethanol required in order to produce particles of any target diameter within this size range. In addition, it was found that the reaction was completed in approximately 2 h for all batches regardless of the volume of ethanol. Structurally coloured artificial opal photonic crystals (PCs) were fabricated from the prepared SNPs by self-assembly under gravity sedimentation.

  18. Synthesis and Photocatalytic Property of ZnO/TiO2 Inverse Opals Films with Controllable Composition and Topology

    Science.gov (United States)

    Xu, Jiao; Yang, Bei-fang; Fu, Zheng-ping; Wen, Mei-wang; Zhao, Yong-xun

    2012-04-01

    A novel method to fabricate composition- and topology-controlled ZnO/TiO2 inverse opals (IO) films using a positive sacrificial ZnO IO template has been developed. This method includes a two-step process, preparation of ZnO IO by a simple electrochemical deposition using a self-assembly polystyrene colloidal crystal template and preparation of ZnO/TiO2 IO by a liquid phase deposition (LPD) process at room temperature. The composition and topology of ZnO/TiO2 IO can be easily controlled by changing the duration of the LPD. After 20 min LPD process, a ZnO/TiO2 composite IO with non-close-packed face-centered cubic air sphere array was obtained. Prolonging the duration to 60 min, a pure TiO2 IO (TIO-LPD60) with obviously thickened walls was formed. The formation mechanism for the compositional and topological variation was discussed. A preliminary study on UV photocatalytic property of the samples for degradation of methylene blue reveals that the composition and topology significantly influenced the photocatalytic activity of the IO film. The ZnO/TiO2 composite IO demonstrates a higher degree of activity than both pure ZnO and pure TiO2 IO, although they have a similar IO wall thickness. Moreover, with increasing IO wall thickness from ~52 nm to ~90 nm, TIO-LPD60 exhibits the highest level of photocatalytic performance.

  19. Sol–gel preparation of well-adhered films and long range ordered inverse opal films of BaTiO{sub 3} and Bi{sub 2}Ti{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Al-Arjan, Wafa S. [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); King Faisal University, PO Box 380, Al Hofuf (Saudi Arabia); Algaradah, Mohammed M.F. [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); King Khalid College, Riyadh (Saudi Arabia); Brewer, Jack [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Hector, Andrew L., E-mail: a.l.hector@soton.ac.uk [Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom)

    2016-02-15

    Highlights: • Highly adaptable sols are presented for processing of the electroceramic materials BaTiO{sub 3} and Bi{sub 2}Ti{sub 2}O{sub 7}. • High quality thin films are produced by dip coating with good phase control. • Infiltration of cross-linked polystyrene templates led to high quality inverse opals. - Abstract: Barium and bismuth titanate thin films and well-ordered inverse opal films are produced by dip coating from sols containing titanium alkoxides with acetic acid, acetylacetone, methoxyethanol and water. The inverse opal preparations used crosslinked polystyrene opal templates. Heat treatment in air produced tetragonal BaTiO{sub 3} or mixtures of the hexagonal and tetragonal phases, or phase pure Bi{sub 2}Ti{sub 2}O{sub 7}. Good quality films were obtained with a thickness of 5 μm from a single dipping, and the thickness could be increased by dipping multiple times. Inverse opals were well ordered and exhibited opalescence and photonic stop band effects.

  20. Tests of perturbative and non perturbative structure of moments of hadronic event shapes using experiments JADE and OPAL; Untersuchung perturbativer und nichtperturbativer Struktur der Momente hadronischer Ereignisformvariablen mit den Experimenten JADE und OPAL

    Energy Technology Data Exchange (ETDEWEB)

    Pahl, Christoph Johannes

    2008-01-29

    In hadron production data of the e{sup +}e{sup -} annihilation experiments JADE and OPAL we measure the first five moments of twelve hadronic-event-shape variables at c.m. energies from 14 to 207 GeV. From the comparison of the QCD NLO prediction with the data corrected by means of MC models about hadronization we obtain the reference value of the strong coupling {alpha}{sub s}(M{sub Z{sup 0}})=0.1254{+-}0.0007(stat.){+-}0.0010(exp.){sup +0.0009}{sub -0.0023}(had.){sup +0.0069}{sub -0.0053}(theo.). For some, especially higher moments, systematic unsufficiencies in the QCD NLO prediction are recognizable. Simultaneous fits to two moments under assumption of identical renormalization scales yield scale values from x{sub {mu}}=0.057 to x{sub {mu}}=0.196. We check predictions of different non-perturbative models. From the single-dressed-gluon approximation a perturbative prediction in O({alpha}{sup 5}{sub s}) results with neglegible energy power correction, which describes the thrust average on hadron level well with {alpha}{sub s}(M{sub Z{sup 0}})=0.1186{+-}0,0017(exp.){sub -0.0028}{sup +0.0033}(theo.). The variance of the event-shape variable is measured and compared with models as well as predictions. [German] In Hadronproduktionsdaten der e{sup +}e{sup -}-Vernichtungsexperimente JADE und OPAL messen wir die ersten fuenf Momente von zwoelf hadronischen Ereignisformvariablen bei Schwerpunktsenergien von 14 bis 207 GeV. Aus dem Vergleich der QCD NLO-Vorhersage mit den mittels MC-Modellen um Hadronisierung korrigierten Daten erhalten wir den Referenzwert der starken Kopplung {alpha}{sub s}(M{sub Z{sup 0}})=0.1254{+-}0.0007(stat.){+-}0.0010(exp.){sup +0.0009}{sub -0.0023}(had.){sup +0.0069}{sub -0.0053}(theo.). Fuer einige, insbesondere hoehere, Momente sind systematische Unzulaenglichkeiten in der QCD NLO-Vorhersage erkenntlich. Simultane Fits an zwei Momente unter Annahme identischer Renormierungsskalen ergeben Skalenwerte von x{sub {mu}}=0.057 bis x{sub {mu}}=0

  1. 奥普尔HA202提高早花菜心产量的作用%Effects on OPAL HA202 Raising the Yield of Early Flower Brossica Chinensis

    Institute of Scientific and Technical Information of China (English)

    陈跃进; 陈勇; 任敬民; 胡民强; 周娜芳

    2008-01-01

    用奥普尔(OPAL)HA202对早花菜心进行浸种和喷叶,以提高菜心产量.结果表明:施用OPAL HA202的菜心小区平均产量834g,比施用清水的对照增产41.4%,增产极显著,因为OPAL HA202增加了菜心的株高、叶片开展度、茎粗和茎叶干物重.与之对比施用吲哚丁酸(IBA)的菜心小区平均产量675g,比清水对照增产14.4%,增产不显著.

  2. Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to late Pliocene/early Pleistocene climate cooling

    Directory of Open Access Journals (Sweden)

    J. Etourneau

    2012-03-01

    Full Text Available The global late Pliocene/early Pleistocene cooling (~3.0–2.0 million years ago, Ma concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela Upwelling System (BUS, off Namibia, where it is known as the Matuyama Diatom Maximum (MDM. Our study focuses on a new diatom silicon isotope (δ30Si record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilization in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Plio/Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to late Pliocene/early Pleistocene cooling.

  3. Plasmon-Sensitized Graphene/TiO2 Inverse Opal Nanostructures with Enhanced Charge Collection Efficiency for Water Splitting.

    Science.gov (United States)

    Boppella, Ramireddy; Kochuveedu, Saji Thomas; Kim, Heejun; Jeong, Myung Jin; Marques Mota, Filipe; Park, Jong Hyeok; Kim, Dong Ha

    2017-03-01

    In this contribution we have developed TiO2 inverse opal based photoelectrodes for photoelectrochemical (PEC) water splitting devices, in which Au nanoparticles (NPs) and reduced graphene oxide (rGO) have been strategically incorporated (TiO2@rGO@Au). The periodic hybrid nanostructure showed a photocurrent density of 1.29 mA cm(-2) at 1.23 V vs RHE, uncovering a 2-fold enhancement compared to a pristine TiO2 reference. The Au NPs were confirmed to extensively broaden the absorption spectrum of TiO2 into the visible range and to reduce the onset potential of these photoelectrodes. Most importantly, TiO2@rGO@Au hybrid exhibited a 14-fold enhanced PEC efficiency under visible light and a 2.5-fold enrichment in the applied bias photon-to-current efficiency at much lower bias potential compared with pristine TiO2. Incident photon-to-electron conversion efficiency measurements highlighted a synergetic effect between Au plasmon sensitization and rGO-mediated facile charge separation/transportation, which is believed to significantly enhance the PEC activity of these nanostructures under simulated and visible light irradiation. Under the selected operating conditions the incorporation of Au NPs and rGO into TiO2 resulted in a remarkable boost in the H2 evolution rate (17.8 μmol/cm(2)) compared to a pristine TiO2 photoelectrode reference (7.6 μmol/cm(2)). In line with these results and by showing excellent stability as a photoelectrode, these materials are herin underlined to be of promising interest in the PEC water splitting reaction.

  4. Slow photon amplification of gas-phase ethanol photo-oxidation in titania inverse opal photonic crystals

    Science.gov (United States)

    Jovic, Vedran; Idriss, Hicham; Waterhouse, Geoffrey I. N.

    2016-11-01

    Here we describe the successful fabrication of six titania inverse opal (TiO2 IO) photocatalysts with fcc[1 1 1] pseudo photonic band gaps (PBGs) tuned to span the UV-vis region. Photocatalysts were fabricated by a colloidal crystal templating and sol-gel approach - a robust and highly applicable bottom-up scheme which allowed for precise control over the geometric and optical properties of the TiO2 IO photocatalysts. Optical properties of the TiO2 IO thin films were investigated in detail by UV-vis transmittance and reflectance measurements. The PBG along the fcc[1 1 1] direction in the TiO2 IOs was dependent on the inter-planar spacing in the [1 1 1] direction, the incident angle of light and the refractive index of the medium filling the macropores in the IOs, in agreement with a modified Bragg's law expression. Calculated photonic band structures for the photocatalysts revealed a PBG along the Γ → L direction at a/λ ∼ 0.74, in agreement with the experimental optical data. By coupling the low frequency edge of the PBG along the [1 1 1] direction with the electronic absorption edge of anatase TiO2, a two-fold enhancement in the rate of gas phase ethanol photo-oxidation in air was achieved. This enhancement appears to be associated with a 'slow photon' effect that acts to both enhance TiO2 absorption and inhibit spontaneous emission (i.e. suppress electron-hole pair recombination).

  5. Synthesis and Photocatalytic Property of ZnO/TiO2 Inverse Opals Films with Controllable Composition and Topology

    Institute of Scientific and Technical Information of China (English)

    Jiao Xu; Bei-fang Yang; Zheng-ping Fu; Mei-wang Wen; Yong-xun Zhao

    2012-01-01

    A novel method to fabricate composition- and topology-controlled ZnO/TiO2 inverse opals (IO) films using a positive sacrificial ZnO IO template has been developed.This method includes a two-step process,preparation of ZnO IO by a simple electrochemical deposition using a self-assembly polystyrene colloidal crystal template and preparation of ZnO/TiO2IO by a liquid phase deposition (LPD) process at room temperature.The composition and topology of ZnO/TiO2 IO can be easily controlled by changing the duration of the LPD.After 20 min LPD process,a ZnO/TiO2 composite IO with non-close-packed face-centered cubic air sphere array was obtained.Prolonging the duration to 60 min,a pure TiO2 IO (TIO-LPD60)with obviously thickened walls was formed.The formation mechanism for the compositional and topological variation was discussed.A preliminary study on UV photocatalytic property of the samples for degradation of methylene blue reveals that the composition and topology significantly influenced the photocatalytic activity of the IO film.The ZnO/TiO2 composite IO demonstrates a higher degree of activity than both pure ZnO and pure TiO2 IO,although they have a similar IO wall thickness. Moreover,with increasing IO wall thickness from ~52 nm to ~90 nm,TIO-LPD60 exhibits the highest level of photocatatytic performance.

  6. Dip-in Indicators for Visual Differentiation of Fuel Mixtures Based on Wettability of Fluoroalkylchlorosilane-Coated Inverse Opal Films.

    Science.gov (United States)

    Sedighi, Abootaleb; Qiu, Shuang; Wong, Michael C K; Li, Paul C H

    2015-12-30

    We have developed the dip-in indicator based on the inverse opal film (IOF) for visual differentiation of organic liquid mixtures, such as oil/gasoline or ethanol/gasoline fuel mixtures. The IOF consists of a three-dimensional porous structure with a highly ordered periodic arrangement of nanopores. The specularly reflected light at the interface of the nanopores and silica walls contributes to the structural color of the IOF film. This color disappears when the nanopores are infiltrated by a liquid with a similar refractive index to silica. The disappearance of the structural color provides a means to differentiate various liquid fuel mixtures based on their wettability of the nanopores in the IOF-based indicators. For differentiation of various liquid mixtures, we tune the wettability threshold of the indicator in such a way that it is wetted (color disappears) by one liquid but is not wetted by the other (color remains). Although colorimetric differentiation of liquids based on IOF wettability has been reported, differentiation of highly similar liquid mixtures require complicated readout approaches. It is known that the IOF wettability is controlled by multiple surface properties (e.g., oleophobicity) and structural properties (e.g., neck angle and film thickness) of the nanostructure. Therefore, we aim to exploit the combined tuning of these properties for differentiation of fuel mixtures with close compositions. In this study, we have demonstrated that, for the first time, the IOF-based dip-in indicator is able to detect a slight difference in the fuel mixture composition (i.e., 0.4% of oil content). Moreover, the color/no-color differentiation platform is simple, powerful, and easy-to-read. This platform makes the dip-in indicator a promising tool for authentication and determination of fuel composition at the point-of-purchase or point-of-use.

  7. Inverse opal-inspired, nanoscaffold battery separators: a new membrane opportunity for high-performance energy storage systems.

    Science.gov (United States)

    Kim, Jung-Hwan; Kim, Jeong-Hoon; Choi, Keun-Ho; Yu, Hyung Kyun; Kim, Jong Hun; Lee, Joo Sung; Lee, Sang-Young

    2014-08-13

    The facilitation of ion/electron transport, along with ever-increasing demand for high-energy density, is a key to boosting the development of energy storage systems such as lithium-ion batteries. Among major battery components, separator membranes have not been the center of attention compared to other electrochemically active materials, despite their important roles in allowing ionic flow and preventing electrical contact between electrodes. Here, we present a new class of battery separator based on inverse opal-inspired, seamless nanoscaffold structure ("IO separator"), as an unprecedented membrane opportunity to enable remarkable advances in cell performance far beyond those accessible with conventional battery separators. The IO separator is easily fabricated through one-pot, evaporation-induced self-assembly of colloidal silica nanoparticles in the presence of ultraviolet (UV)-curable triacrylate monomer inside a nonwoven substrate, followed by UV-cross-linking and selective removal of the silica nanoparticle superlattices. The precisely ordered/well-reticulated nanoporous structure of IO separator allows significant improvement in ion transfer toward electrodes. The IO separator-driven facilitation of the ion transport phenomena is expected to play a critical role in the realization of high-performance batteries (in particular, under harsh conditions such as high-mass-loading electrodes, fast charging/discharging, and highly polar liquid electrolyte). Moreover, the IO separator enables the movement of the Ragone plot curves to a more desirable position representing high-energy/high-power density, without tailoring other battery materials and configurations. This study provides a new perspective on battery separators: a paradigm shift from plain porous films to pseudoelectrochemically active nanomembranes that can influence the charge/discharge reaction.

  8. Preparation of 3D Colloidal Crystal Film and Gold-Infiltrated Silica Artificial Opals%3D胶状晶体膜及其渗透金的氧化硅人工蛋白石的制备

    Institute of Scientific and Technical Information of China (English)

    李文江; 谢飞

    2007-01-01

    A free-standing 3D colloidal crystal film (opal) was fabricated at a water-air interface using purified monodispersed SiO2 colloids. The gold/silica opal was obtained through the infiltration of gold nanoparticles by electroplating. The transmission and reflection spectra of the gold/silica composite opal show a red shift with increasing electroplating time.SEM images show that gold nanoparticles can be directly deposited on the surface of silica spheres in the opaline structure. Gold/silica composite opal film could provide a simple way to tune opal properties through controlling the amount of gold in the silica opal.%用纯的单分散氧化硅胶体微球作为基质,在水-空气界面构筑无载体三维有序胶质晶体膜.该高度有序三维周期性结构具有明显的光学衍射现象.利用电沉积的方法将纳米金渗透到这种人工蛋白石的空隙中,构成gold/silica复合蛋白石材料.详细研究了该复合蛋白石的透射光谱和反射光谱,用扫描电镜观察了复合蛋白石结构的形貌特征,并对渗透金后蛋白石的光谱移动进行了分析.

  9. Application of a nanoEA-IRMS system for δ13C measurement of biomineral-bound organics in samples of diatom opal with nanomolar quantities of C

    Science.gov (United States)

    Méndez-Vicente, Ana; María Mejía-Ramírez, Luz; Stoll, Heather

    2013-04-01

    We describe the isotopic measurement of δ13C in very small samples of diatom opal (nanomolar quantities of C) both from fossil sediments and cultures. We use a nano-EA system composed of a combustion elemental analyzer (EA3000 series, Eurovector), with standard 18 mm diameter quartz oxidation-reduction reactors and an ash removal device that aids in removal of uncombusted opal and ensures a long reactor lifetime. This is coupled to a custom designed trapping and cromatography system (Nano-CF, Nu Instruments Ltd.) which cryogenically removes CO2 generated by sample combustion and introduces the gas into a low-flow helium carrier stream to the mass spectrometer (Nu Perspective IRMS instrument, Nu Instruments Ltd.). This technique allows for an important reduction in the minimum sample requirements for analysis compared to a typical EA, however the need to reduce the contribution of the blank to the measured values becomes all the more critical. Blank from the capsules can be minimized through specific protocols including cleaning with solvents and reducing the size of the capsule by cutting it to a smaller size, attaining blanks as low as 13.75±2.15 nmol C. Under these conditions we can accurately measure both standards and diatom reference materials in the range of 100 to 330 nmol C, with a precision of 2σ 10 ‰ analysed in sequence. Applied to measure biomineral-bound organics in cleaned diatom samples from sediments, the low sample size requirements of this technique allows us to analyse multiple size fractions within one sample, and explore isotopic fractionation patterns between them. We have analysed samples from sediments of both centric and pennate diatoms typically in the range of 200 to 1300 µg of cleaned opal. Analysis of culture samples of Thalassiosira pseudonana of 20 to 150 µg of cleaned opal, allows us to evaluate if there is covariation of the whole cell particulate organic carbon (POC) and diatom-bound δ13C values. Initial results suggest

  10. Determination of the mass and width of the W-boson using the semileptonic decay channel with the OPAL detector at LEP

    CERN Document Server

    Vollmer, Cornelius Fritz

    2004-01-01

    Diese Arbeit ist eine Weiterentwicklung der beim OPAL-Experiment verwendeten Faltungsmethode zur Bestimmung der Masse des geladenen Eichbosons der schwachen Wechselwirkung. Die Methode wurde ausgeweitet auf eine gleichzeitige Bestimmung der Masse Mw und der Zerfallsbreite Gw des W-Boson genannten Eichbosons. Analysiert wurden dazu Daten, die mit dem OPAL-Experiment in den Jahren 1997 bis 2000 aufgezeichnet wurden. Von den möglichen Zerfällen der erzeugten W-Bosonpaare werden nur semileptonische betrachtet, bei denen ein W-Boson hadronisch in ein Quark-Antiquark-Paar zerfällt und das andere in ein geladenes Lepton und ein Neutrino. In der Faltungsmethode werden die aus der Detektorauflösung resultierenden Fehler der einzelnen Ereignisse berücksichtigt. Dazu wird eine Funktion P(m) für jedes Ereignis ermittelt, welche die Wahrscheinlichkeit angibt, daß die produzierten W-Bosonen eine mittlere Masse m haben. Diese sogenannte Ereigniswahrscheinlichkeitsdichte wird mit einer Physikfunktion PF(m;Mw,Gw) gefal...

  11. Opal-replaced "Phenocrysts" in Fresh Pumice from 1817 Phreatomagmatic Deposits from Kawah Ijen, East Java, Indonesia: Implications for Eruptive Timescales?

    Science.gov (United States)

    Lowenstern, J. B.; Wright, H. M. N.; van Hinsberg, V.; Berlo, K.; Iacovino, K.; Bindeman, I. N.

    2016-12-01

    Pumice: Opal-replaced plagioclase and pyroxene are in apparently unaltered dacite pumice from the 1817 phreatomagmatic eruption at Kawah Ijen, an arc volcano with a hyperacidic crater lake. Some remnants of replaced phenocrysts are visible as cores within the euhedral opalcrysts (0.01 to 3 mm in size). The pumice matrix glass is microlite-free and shows no evidence of alteration. Fresh non-opaline phenocryst phases include pyroxene, Fe-Ti oxide, apatite, and sulfide. FTIR and TCEA analyses demonstrate that the opal contains > 2-4 wt.% H2O. D/H ratios range from -115 to -155 ‰, far below meteoric or crater lake waters ( 0) or the bulk dacite (-86±3), and higher in oxygen 18/16 than the pumice (12.6 vs. 7.2 ‰). Other opaline material is found as layered colloidal lithics ( 750°C for <24 hours, caused the opalcrysts to dehydrate and convert to crystalline SiO2 forms. The origin of the opalcrysts remains confounding, and we continue to explore options for their origin.

  12. Photonic crystal heterostructures fabricated by TiO2 and ZnO inverse opals using colloidal crystal template with single kind of microspheres

    Science.gov (United States)

    Zhang, Yongna; Fu, Ming; Wang, Jigang; He, Dawei; Wang, Yongsheng

    2012-09-01

    The fabrication of photonic crystal heterostructures is important for the applications in the fields of integrated photonic crystal chips, multi-frequency optical Bragg filters or mirrors. However, multiple steps of self-assembly process of microspheres are always employed in the fabrication of photonic crystal heterostructures, which may produce lattice mismatches of colloidal crystals. Therefore, photonic crystal heterostructures fabricated by using colloidal crystal template with single kind of microspheres were investigated in this paper. A colloidal crystal template with uniform periodicity was firstly formed by monodispersed polystyrene microsphere. Then ZnO was electrodeposited into the interstices of the template. The thickness of ZnO was controlled to be less than the thickness of the template by varying the deposition time. After the TiO2 precursor was filled into the top voids in the template, the polystyrene colloidal crystal template was removed and photonic crystal heterostructures fabricated by ZnO and TiO2 were formed. Both the dielectric constant and the periodicity of the two parts of the heterostructures are different due to the shrinkage of the sol-gel process. The ZnO/TiO2 heterostructures have a broad photonic stop band which is the superposition of photonic stop bands of ZnO inverse opals and TiO2 inverse opals.

  13. Changes and influencing factors in biogenic opal export productivity in the Bering Sea over the last 4.3 Ma: Evidence from the records at IODP Site U1340

    Science.gov (United States)

    Zhang, Qiang; Chen, Muhong; Zhang, Lanlan; Su, Xiang; Xiang, Rong

    2016-08-01

    We reconstructed changes in biogenic opal export productivity (BOEP) in the southern Bering Sea (BS) over the last ˜4.3 Ma, based on mass accumulation rate (MAR) of biogenic opal from Integrated Ocean Drilling Program (IODP) Site U1340. The results show that the BOEP in the BS was high and variable between ˜4.3 and ˜1.9 Ma, extremely low and relatively stable from ˜1.9 to ˜1.1 Ma, and then fluctuated frequently (generally high during interglacials and low during glacials) during the last ˜1.1 Ma. One interval of enhanced BOEP from ˜4.3 to ˜3.2 Ma is a response to the Late Miocene-Early Pliocene "Biogenic Bloom Event." Another interval from ˜2.8 to ˜1.9 Ma correlates with global opal burial shifting from high-latitude oceans to upwelling-influenced regions following the intensification of the Northern Hemisphere Glaciation (NHG). Whereas, the increase in BS opal export productivity during the last ˜1.1 Ma tends to be a "local" phenomenon. Overall, the BOEP shows a similar trend and good correspondence to the input of the Alaskan Stream (AS), which can be traced using the Na2O/K2O ratio. We thus conclude that the AS may be the direct, and primary factor on BOEP variability in the BS during the last ˜4.3 Ma. In addition, although the poor correlation between opal MAR and volcanic glass suggests that BOEP variability was not controlled by long-term variations in the volcanism or ash abundance, increased ash abundance indicated by high contents of volcanic glasses was also a possible reason for enhanced BOEP during the period from ˜4.3 to ˜3.2 Ma and the last ˜0.5 Ma.

  14. 反蛋白石结构光子晶体及其应用的研究∗%Research and Application of Inverse Opal Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    单晶; 谭天亚; 张春玉; 步秋雨; 韩亚洲; 季亚楠; 张帆; 梅勇; 徐攀峰; 王绩伟

    2016-01-01

    反蛋白石结构光子晶体因具有完全光子带隙、制备材料广泛、特殊的周期结构、大的比表面积和连通的孔洞结构,近年来在自发辐射的调制、提高光催化反应速率和染料敏化太阳能电池反应速率等领域成为研究热点之一,并且在光、电、催化、传感、显示、检测等领域有着巨大的应用价值。介绍了反蛋白石结构光子晶体的基本概念及制备方法,阐述了反蛋白石结构在材料自发辐射的调制、能量传递的调制、促进物理化学反应、外界环境响应材料等方面的作用及其应用。%Inverse opal structure with the properties of complete photonic band gap,extensive preparation ma-terials,periodic structure,large specific surface area and connected holes has great importance in the domains of spon-taneous emission modulation,enhancing efficiency of photocatalysis and improving photielectric conversion efficiency of the dye sensitized cell in recent years.This structure has high value and huge potential in optics,electronics,catal-ysis,sensor,display,detection and so on.This paper introduces the basic concepts of inverse opal structure and de-scribes several applications of inverse opal structure,such as preparation method,spontaneous emission modulation, energy transfer modulation,promoting physical reactions,promoting chemical reactions and external environmental response materials.

  15. A Lesson from Opal.

    Science.gov (United States)

    Keiper, Anne M.

    1987-01-01

    A five-year-old hearing impaired girl who arrives at a residential school for the deaf without having had the opportunity to learn to communicate goes through the early stages of writing development. Similarities between the developmental stages of oral and written language and the importance of providing behavior models are discussed. (VW)

  16. OPAL Land Condition Model

    Science.gov (United States)

    2014-08-01

    around April at about 150 grams/m2 (Figure 8). Without training it peaks at about 300 grams/m2. Now, trade the hot dry year for a cool wet year...be spelled out to provide contex- tual meaning to the programmer. They can take any, or a mix, of sever- al forms. Often the first letter in a string

  17. Studies on Inverse Opal and Two-Dimensional Nonlinear Photonic Crystals%反Opal及二维非线性光子晶体的研究

    Institute of Scientific and Technical Information of China (English)

    倪培根; 程丙英; 张道中

    2006-01-01

    通过向SiO2 Opal模板中填充钛酸乙酯制备TiO2光子晶体,观测到光子晶体带隙位置的移动达62nm,并发现光子晶体的有序度随填充率的升高而下降.向聚苯乙烯Opal模板中填充钛酸乙酯,制备成当时填充率最高、带隙最短的紫外波段TiO2反Opal光子晶体(中心波长~380nm),并根据测量的其透射谱估算出其填充率约为12%,即Opal模板孔隙的50%被填充.本文还对二维PPLN光子晶体进行了研究.建立了一套高压极化装置和电压数据采集装置,通过外加电场极化法成功制备出了具有正方形和矩形两种晶格形状二维PPLN光子晶体.利用二维PPLN的二阶准相位匹配,测量了其对1.064μm激光的二次谐波转换效率,并研究了晶体的温度、激光的入射角度及占空比对二次谐波转换效率的影响.利用矩形晶格实现了多方向、多波长倍频高效输出.%In this paper, we report some results on inverse opal photonic crystal and two-dimensional periodically poled lithium niobate photonic crystal. First, the process of infiltrating TiO2 into SiO2 Opal was systematically studied. Because of the infiltration of TiO2, the gap of SiO2 Opal was shifted to longer wavelength and a maximum shift of 62nm was observed. Furthermore, an inverse TiO2 Opal with larger filling fraction, ~ 12%, was fabricated, whose band gap in the Γ-L direction is located in the ultraviolet region ( ~ 380nm). Then two-dimensional nonlinear photonic crystals of lithium nlobate with uniform square lattices were fabricated by applying external electric fields. The variations of second-harmonic output with crystal temperatures, incident angles and reversed duty cycles were measured. Red, yellow,green, blue, and violet coherent radiations were generated in the nonlinear photonic crystal with rectangular lattice in the collinearly and non-collinearly quasi-phase matching geometries. The results showed that two-dimensional nonlinear photonic crystal

  18. Optimization of lasing in an inverted-opal titania photonic crystal cavity as an organic solid-state dye-doped laser.

    Science.gov (United States)

    Zhang, Dingke; Chen, Shijian; Jiang, Maohua; Ye, Lijuan

    2014-11-10

    Lasing performance of a dye-doped laser by encapsulating orange fluorescent dye 4-(Dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) with different concentrations in a highly ordered three-dimensional (3D) inverted-opal titania (TiO2) photonic crystal (PC) microcavity was studied. The lasing threshold and laser quality were improved by optimizing the concentration of the laser dye DCM. When the concentration of DCM is optimized to 10-4  mol/l, the photoluminescence (PL) efficiency of DCM is sufficient to achieve lasing emission and meanwhile no fluorescence quantum quenching occurs. Therefore, the emission spectrum was greatly narrowed and the threshold was significantly improved, which reached 0.8  mJ pulse-1 cm-2. Our findings are promising results toward the realization of fabricating a highly efficient low-threshold organic laser.

  19. Search for R-parity violating decays of supersymmetric particles in final states with jets and leptons using the OPAL detector at LEP

    CERN Document Server

    Mutter, Andreas

    2004-01-01

    Of all the data of the years 1998 to 2000 taken with the OPAL detector at the e+e-- collider LEP at CERN, final states with jets and leptons have been analysed. A search for decays of new particles postulated by supersymmetric extensions of the standard model of particle physics has been performed. Only decays violating the quantum number R-parity (Rp) that is introduced in supersymmetric models have been investigated. The violation of Rp leads to experimental signatures that are in general completely different from those in the Rp conserving case. If Rp is violated, processes that lead to a rapid decay of the proton might be possible. In order to avoid such processes, in most investigations Rp is assumed to be conserved. However, there is no theoretically compelling reason for this assumption. Therefore, the possibility of R-parity violation should also be considered.

  20. Determination of {alpha}{sub S} using OPAL hadronic event shapes at {radical}(s)= 91-209{proportional_to}GeV and resummed NNLO calculations

    Energy Technology Data Exchange (ETDEWEB)

    Abbiendi, G.; Braibant, S.; Capiluppi, P.; Ciocca, C.; Cuffiani, M.; Dallavalle, M.; Fabbri, F.; Giacomelli, G.; Giacomelli, P.; Mader, W.; Mes, H.; Renkel, P. [Univ. di Bologna (Italy); INFN, Bologna (Italy); Ainsley, C.; Batley, R.J.; Carter, J.R.; Hill, J.C.; Tasevsky, M.; Voss, H.; Vossebeld, J. [Cavendish Lab., Cambridge (United Kingdom); Aakesson, P.F.; Barberio, E.; Burckhart, H.J.; Roeck, A. de; Wolf, E.A. de; Ferrari, P.; Frey, A.; Gruwe, M.; Hauschild, M.; Hawkings, R.; Heuer, R.D.; McKenna, J.; Neal, H.A.; Pilcher, J.E.; Plane, D.E.; Przybycien, M.; Quadt, A.; Sachs, K.; Schaile, A.D.; Scharff-Hansen, P.; Schieck, J.; Schumacher, M.; Sherwood, P.; Stroehmer, R.; Torrence, E.; Vertesi, R.; Verzocchi, M.; Watson, A.T.; Watson, N.K. [European Organisation for Nuclear Research, CERN, Geneva 23 (Switzerland); Alexander, G.; Bella, G.; Etzion, E.; Grunhaus, J.; Trigger, I. [Tel Aviv Univ., Dept. of Physics and Astronomy, Tel Aviv (Israel); Anagnostou, G.; Bell, P.J.; Charlton, D.G.; Hawkes, C.M.; Jovanovic, P.; Nanjo, H.; Trocsanyi, Z.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Wermes, N. [Univ. of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Anderson, K.J.; Gupta, A.; Meijers, F.; O' Neale, S.W.; Pasztor, G.; Sobie, R.; Tarem, S. [Univ. of Chicago, Enrico Fermi Inst. and Dept. of Physics, Chicago, IL (United States); Asai, S.; Ishii, K.; Kanzaki, J.; Kawagoe, K.; Kawamoto, T.; Kobayashi, T.; Komamiya, S.; Martin, A.J.; Meyer, N.; Miller, D.J.; Mutter, A.; Nagai, K.; Oh, A.; Runge, K.; Thomson, M.A.; Tsur, E.; Wolf, G. [Univ. of Tokyo (Japan); Kobe Univ. (Japan); Axen, D.; Loebinger, F.K.; Mashimo, T. [Univ. of British Columbia, Dept. of Physics, Vancouver, BC (Canada); Bailey, I.; Karlen, D.; Keeler, R.K.; Maettig, P.; Rembser, C.; Skuja, A. [Univ. of Victoria (Canada); Barillari, T.; Bethke, S.; Kluth, S.; Oreglia, M.J.; Pooth, O.; Schaile, O. [Max-Planck-Inst. fuer Physik, Muenchen (Germany)] [and others

    2011-09-15

    Hadronic event shape distributions from e{sup +}e{sup -} annihilation measured by the OPAL experiment at centre-of-mass energies between 91 GeV and 209 GeV are used to determine the strong coupling {alpha}{sub S}. The results are based on QCD predictions complete to the next-to-next-to-leading order (NNLO), and on NNLO calculations matched to the resummed next-to-leading-log-approximation terms (NNLO + NLLA). The combined NNLO result from all variables and centre-of-mass energies is while the combined NNLO + NLLA result is The completeness of the NNLO and NNLO + NLLA results with respect to missing higher order contributions, studied by varying the renormalization scale, is improved compared to previous results based on NLO or NLO + NLLA predictions only. The observed energy dependence of {alpha}{sub S} agrees with the QCD prediction of asymptotic freedom and excludes the absence of running. (orig.)

  1. Adaptive optics correction into single mode fiber for a low Earth orbiting space to ground optical communication link using the OPALS downlink.

    Science.gov (United States)

    Wright, Malcolm W; Morris, Jeffery F; Kovalik, Joseph M; Andrews, Kenneth S; Abrahamson, Matthew J; Biswas, Abhijit

    2015-12-28

    An adaptive optics (AO) testbed was integrated to the Optical PAyload for Lasercomm Science (OPALS) ground station telescope at the Optical Communications Telescope Laboratory (OCTL) as part of the free space laser communications experiment with the flight system on board the International Space Station (ISS). Atmospheric turbulence induced aberrations on the optical downlink were adaptively corrected during an overflight of the ISS so that the transmitted laser signal could be efficiently coupled into a single mode fiber continuously. A stable output Strehl ratio of around 0.6 was demonstrated along with the recovery of a 50 Mbps encoded high definition (HD) video transmission from the ISS at the output of the single mode fiber. This proof of concept demonstration validates multi-Gbps optical downlinks from fast slewing low-Earth orbiting (LEO) spacecraft to ground assets in a manner that potentially allows seamless space to ground connectivity for future high data-rates network.

  2. Highly active surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles infiltrated into SiO{sub 2} inverse opals

    Energy Technology Data Exchange (ETDEWEB)

    Ankudze, Bright; Philip, Anish [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Pakkanen, Tuula T., E-mail: Tuula.Pakkanen@uef.fi [Department of Chemistry, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland); Matikainen, Antti; Vahimaa, Pasi [Institute of Photonics, University of Eastern Finland, P.O. Box 111, F1-80101, Joensuu (Finland)

    2016-11-30

    Highlights: • SERS substrates prepared by infiltration of nanoparticles into SiO{sub 2} inverse opal. • The SERS substrate gives an enhancement factor of 10{sup 7} for 4-aminothiophenol. • The sensitivity of the substrate is mainly attributed to gold nanoparticle clusters. - Abstract: SiO{sub 2} inverse opal (IO) films with embedded gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) application are reported. SiO{sub 2} IO films were loaded with AuNPs by a simple infiltration in a single cycle to form Au-SiO{sub 2} IOs. The optical property and the morphology of the Au-SiO{sub 2} IO substrates were characterized; it was observed that they retained the Bragg diffraction of SiO{sub 2} IO and the localized surface plasmon resonance (LSPR) of AuNPs. The SERS property of the Au-SiO{sub 2} IO substrates were studied with methylene blue (MB) and 4-aminothiophenol (4-ATP). The SERS enhancement factors were 10{sup 7} and 10{sup 6} for 4-ATP and MB, respectively. A low detection limit of 10{sup −10} M for 4-ATP was also obtained with the Au-SiO{sub 2} IO substrate. A relative standard deviation of 18.5% for the Raman signals intensity at 1077 cm{sup −1} for 4-ATP shows that the Au-SiO{sub 2} IO substrates have good signal reproducibility. The results of this study indicate that the Au-SiO{sub 2} IO substrates can be used in sensing and SERS applications.

  3. Enhanced recycling of organic matter and Os-isotopic evidence for multiple magmatic or meteoritic inputs to the Late Permian Panthalassic Ocean, Opal Creek, Canada

    Science.gov (United States)

    Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.; Henderson, Charles M.; Algeo, Thomas J.

    2015-02-01

    The geochemical record for the Permian-Triassic boundary in northern latitudes is essential to evaluation of global changes associated with the most profound extinction of life on Earth. We present inorganic and organic geochemical data, and Re-Os isotope systematics in a critical stratigraphic interval of pre- and post-extinction Upper Permian-Lower Triassic sediments from Opal Creek, western Canada (paleolatitude of ∼30°N). We document significant and long-lived changes in Panthalassa seawater chemistry that were initiated during the first of four magmatic or meteoritic inputs to Late Permian seawater, evidenced by notable decreases of Os isotopic ratios upsection. Geochemical signals indicate establishment of anoxic bottom waters shortly after regional transgression reinitiated sedimentation in the Late Permian. Euxinic signals are most prominent in the Upper Permian sediments with low organic carbon and high sulfur contents, and gradually wane in the Lower Triassic. The observed features may have been generated in a strongly euxinic ocean in which high bacterioplankton productivity sustained prolific microbial sulfate reduction in the sediment and/or water column, providing hydrogen sulfide to form pyrite. This scenario requires nearly complete anaerobic decomposition of predominantly labile marine organic matter (OM) without the necessity for a complete collapse of primary marine productivity. Similar geochemical variations could have been achieved by widespread oxidation of methane by sulfate reducers after a methanogenic burst in the Late Permian. Both scenarios could have provided similar kill mechanisms for the latest Permian mass extinction. Despite the moderate thermal maturity of the section, OM in all studied samples is dominantly terrestrial and/or continentally derived, recycled and refractory ancient OM. We argue that, as such, the quantity of the OM in the section mainly reflects changes in terrestrial vegetation and/or weathering, and not in

  4. Modification of ZnS-inserting layer in the TiO2 inverse opal-based photoanode to enhance the efficiency of quantum dot-sensitized solar cells

    Science.gov (United States)

    Deng, Fei; Wan, Xiangyu; Mei, Xingan; Fan, Runzhou; Yan, Xuemin; Wan, Li; Shi, Dean; Xiong, Yan

    2016-07-01

    Modification of ZnS-inserting layer in the titanium dioxide (TiO2) inverse opal-based photoanode was investigated, and it is an effective and easy approach to enhance the efficiency of quantum dot-sensitized solar cells (QDSSCs). The introduction of ZnS between TiO2 and quantum dots (QDs) not only enhanced the light harvesting of QDs on its top, but also lessened the charge-transfer resistances at the TiO2/QD/electrolyte interfaces. The TiO2 inverse opal-based QDSSCs increased the energy conversion efficiency by modifying the ZnS-inserting layer in the photoanode, particularly the CdS/CdSe QD co-sensitized solar cells which attained 79% rate of increase in cell efficiency.

  5. Spéciation de l'uranium dans l'environnement : application aux opales de Nopal I (Mexique et aux résidus miniers de Gunnar (Canada)

    OpenAIRE

    Othmane, Guillaume

    2012-01-01

    Understanding the processes of uranium migration and sequestration is an important issue for the prediction of radionuclide retardation in the vicinity of uranium mine tailings sites or for the safety assessment of potential high-level nuclear waste repositories. Uranium speciation, controlled by biotic and abiotic factors, represents a key parameter for the control of uranium transfer in the environment. This study firstly deals with uranium speciation in opals from the Nopal I uranium depos...

  6. Etude de la Production des Mesons d* Sur le PIC de Resonance du Boson Z Observes AU Lep avec le Detecteur Opal

    Science.gov (United States)

    Przysiezniak, Helenka

    L'etude de la production des mesons D* est effectuee a partir d'evenements multihadroniques rm Z^0to q| q, avec des donnees prises en 1990, 1991 et 1992 avec le detecteur OPAL au LEP. La notation q definit les quarks des cinq saveurs pouvant etre observees au LEP: up (u), down (d), strange (s), charme (c), beaute (b). Les D* et les correlations D*-leptons sont identifiees et ces dernieres servent a effecteur une separation claire entre les evenements rm Z^0to b| b et Z^0to c| c. On mesure la distribution de la variable de fragmentation x_{rm D^ *}=E_{rm D^*}/E _{rm faisceau} pour les D* produits dans les evenements rm Z^0 to c| c. Elle est notee f _{rm cto D^*}. Ce resultat est a la base d'une publication OPAL (1), avec trois autres methodes de separation etudiees en parallele, donnat la premiere mesure OPAL de f _{rm cto D^*} qui soit independante de toute modelisation de la fragmentation des quarks lourds, ainsi qu'une mesure de Gamma_{rm c| c} parmi les plus precises effectuees a ce jour, ou Gamma_{rm c| c} est la largeur partielle de la desintegration du Z^0 en une paire cc. En ce qui concerne les resultats obtenus dans le cadre de cette these, la valeur moyenne de la distribution f_ {rm cto D^*}, notee cto D^*}>, est donnee par:cto D^*}>=0.530+/-0.027 +/-0.022ou la premiere erreur est statistique, et la seconde est systematique. On mesure aussi le taux de production des mesons D*, donnee par: {Gamma({rm Z^0to D^ *}X)overGamma_{rm hadrons}}=0.207+/-0.007+/-0.017 ou Gamma_{rm hadrons } est la largeur totale de la desintegration du Z^0 en paires de qq des cinq saveurs. La separation entre evenements rm Z^0to b| b et Z^0 to c| c, dans lesquels sont produits des D* se desintegrant selon rm D^ *to D^0pito (Kpi)pi, nous donne:(DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI)La variable de fragmentation x_ {rm cto D^*} est utilisee pour tester les modeles des processes perturbatifs et non-perturbatifs qui entrent en jeu lors de la fragmentation des quarks b et c

  7. Photoelectrochemical detection of alpha-fetoprotein based on ZnO inverse opals structure electrodes modified by Ag2S nanoparticles

    Science.gov (United States)

    Jiang, Yandong; Liu, Dali; Yang, Yudan; Xu, Ru; Zhang, Tianxiang; Sheng, Kuang; Song, Hongwei

    2016-01-01

    In this work, a new photoelectrochemical biosensor based on Ag2S nanoparticles (NPs) modified macroporous ZnO inverse opals structure (IOs) was developed for sensitive and rapid detection of alpha fetal protein (AFP). Small size and uniformly dispersed Ag2S NPs were prepared using the Successive Ionic Layer Adsorption And Reaction (SILAR) method, which were adsorbed on ZnO IOs surface and frame work as matrix for immobilization of AFP. The composite structure of ZnO/Ag2S expanded the scope of light absorption to long wavelength, which can make full use of the light energy. Meanwhile, an effective matching of energy levels between the conduction bands of Ag2S and ZnO are beneficial to the photo-generated electrons transfer. The biosensors based on FTO (fluorine-doped tinoxide) ZnO/Ag2S electrode showed enough sensitivity and a wide linear range from 0.05 ng/mL to 200 ng/mL with a low detection limit of 8 pg/mL for the detection of AFP. It also exhibited high reproducibility, specificity and stability. The proposed method was potentially attractive for achieving excellent photoelectrochemical biosensor for detection of other proteins. PMID:27922086

  8. A sensitive photoelectrochemical biosensor for AFP detection based on ZnO inverse opal electrodes with signal amplification of CdS-QDs.

    Science.gov (United States)

    Xu, Ru; Jiang, Yandong; Xia, Lei; Zhang, Tianxiang; Xu, Lin; Zhang, Shuang; Liu, Dali; Song, Hongwei

    2015-12-15

    In this work, ZnO inverse opals structure (IOs) based photoelectrochemical (PEC) electrode was fabricated for alpha-fetoprotein (AFP) detection. Then, the uniform CdS quantum dots (QDs) were hydrothermally synthesized, which allowed the binding of AFP and glucose oxidase (GOD) on CdS QDs, forming the AFP-CdS-GOD composite. The competitive immunosensor of AFP and the AFP-CdS-GOD composite with anti-AFP antibodies (Ab) immobilized on FTO (fluorine-doped tin oxide) /ZnO IOs electrode was successfully applied to the detection of AFP. GOD could catalyze glucose to produce hydrogen peroxide (H2O2) acting as an electron donor to scavenge photogenerated holes in the valence band of CdS QDs, reducing the recombination of electrons and holes of CdS QDs. Also the effective energy level matching between the conduction bands of CdS QDs and ZnO widened the range of light absorption, allowing for electron injection from excited CdS QDs to ZnO upon visible light irradiation, which enhanced the photocurrent. The results show that the immunosensor of AFP possesses a large linear detection range of 0.1-500 ng/ml with a detection limit of 0.01 ng/ml. It also exhibits excellent anti-interference property and acceptable stability. This work provides a promising method for achieving excellent photoelectrochemical biosensor detection of other proteins.

  9. Measurement of the Strangeness Spectral Function and the Mass of the Strange Quark in Hadronic tau Decays with the OPAL Detector

    CERN Document Server

    Mader, Wolfgang Franz

    2004-01-01

    Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the τ lepton and the mass of the strange quark. The decays τ −→ (Kπ) −ντ , (Kππ) −ντ and (Kπππ) −ντ with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including η mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the τ lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B(τ − → K −π 0 ντ ) = (0.471 ± 0.064stat ± 0.021sys) % B(τ − → K ...

  10. Highly improved upconversion luminescence in NaGd(WO₄)₂:Yb³⁺/Tm³⁺ inverse opal photonic crystals.

    Science.gov (United States)

    Wang, Yunfeng; Xu, Wen; Cui, Shaobo; Xu, Sai; Yin, Ze; Song, Hongwei; Zhou, Pingwei; Liu, Xiaoyan; Xu, Lin; Cui, Haining

    2015-01-28

    The upconversion luminescence (UCL) of rare earth (RE) ions doped nanomaterials has attracted extensive interest because of its wide and great potential applications. However, the lower UCL efficiency is still an obstacle for real applications. Photonic modulation is a novel way to improve the efficiency of UCL. In this work, NaGd(WO4)2:Yb(3+)/Tm(3+) inverse opal photonic crystals (IOPCs) were fabricated through the polymethylmethacrylate (PMMA) template and the modification of the IOPC structure on the emission spectra and dynamics of Tm(3+) ions was systemically studied. It is interesting to observe that in the IOPCs, the high-order UCL (1)D2-(3)H6/(3)F4 was relatively enhanced. At the same time, the local thermal effect induced by laser irradiation was suppressed. Furthermore, the overall intensity ratio of visible UCL to near-infrared (NIR) down-conversion luminescence (DCL) was 2.8-8 times improved than that of the grinded reference (REF) and independent of the photonic stop band (PSB). The studies on UCL dynamics indicated that the nonradiative transition rate of Tm(3+) was considerably suppressed. The facts above indicated that in the IOPCs the UCL efficiency of Tm(3+) was largely improved due to the periodic macroporous structure.

  11. Mesure asymétrie avant-arriere des quarks lourds a LEP1 avec le détecteur OPAL

    CERN Document Server

    Lafoux, H

    A partir de l'ensemble des données accumulées par OPAL au cours de la première phase de fonctionnement du LEP, nous avons mesuré l'asymétrie avant-arrière des quarks b et c au voisinage du pic du Zo. Utilisant une méthode traditionnelle, basée sur la détection des leptons produits dans les désintégrations semi-leptoniques des hadrons lourds, nous avons cherché à optimiser chaque étape de la mesure, en mettant en œuvre les algorithmes les plus appropriés. Le recours aux réseaux de neurones artificiels s'est en particulier avéré d'une grande utilité lorsque le problème à résoudre impliquait la prise en compte simultanée de multiples sources d'informations, d'origine et de nature très variées. Nos résultats sont en bon accord avec ceux des autres mesures effectuées à LEP et compatibles avec les prédictions du Modèle Standard pour un quark top de 174 ± 31 GeV/c2 et un boson de Higgs de masse comprise entre 60 et 1000 GeV/c2

  12. Facile fabrication of sub-100 nm mesoscale inverse opal films and their application in dye-sensitized solar cell electrodes.

    Science.gov (United States)

    Lee, Jung Woo; Lee, Jaemin; Kim, Cheolho; Cho, Chang-Yeol; Moon, Jun Hyuk

    2014-10-28

    Inverse opal (IO) films with mesoporous structures hold promise as high-performance electrodes for various photoelectrochemical devices because of their high specific area as well as their fully connected pore structure. A great challenge to their use is obtaining an intact film of mesoscale colloidal crystals as a template. Here, using the plate-sliding coating method coupled with hot air flow, we successfully deposited mesoscale colloidal crystals onto the substrate. A TiO2 mesoscale IO (meso-IO) with 70 nm pores was then successfully fabricated via atomic layer deposition of TiO2 and subsequent removal of the template. As a photoelectrochemical electrode, the meso-IO structure exhibits enhanced charge transport properties as well as a high specific area. Moreover, dye-sensitized solar cells fabricated using the meso-IO electrode exhibit a higher photocurrent and cell efficiency than a cell constructed using a conventional TiO2 nanoparticle electrode. This meso-IO film provides a new platform for developing electrodes for use in various energy storage and conversion devices.

  13. An ordered and porous N-doped carbon dot-sensitized Bi2O3 inverse opal with enhanced photoelectrochemical performance and photocatalytic activity.

    Science.gov (United States)

    Sun, Yan; Zhang, Zuxing; Xie, Anjian; Xiao, Changhe; Li, Shikuo; Huang, Fangzhi; Shen, Yuhua

    2015-09-01

    A novel ordered porous Bi2O3 inverse opal structure (IOS) was prepared using a polystyrene (PS) photonic crystal as the template for the first time. Nitrogen-doped carbon dots (N-CDs) were chosen to sensitize the as-prepared Bi2O3 IOS for improving photoelectrochemical performance and photocatalytic activity. The photocurrent density of the fabricated N-CDs/Bi2O3 IOS with favorable visible light absorption properties can achieve 0.75 mA cm(-2), which significantly enhanced performance two-, seven-, and thirty-fold compared with that of the CDs/Bi2O3 IOS, Bi2O3 IOS, and Bi2O3 nanoparticles (NPs), respectively. The N-CDs/Bi2O3 IOS also has increased photocatalytic activity for the decolorization of Rhodamine B (RhB), 4 times higher than Bi2O3 NPs. The above performance enhancement of N-CDs/Bi2O3 IOS is caused by the synergistic effect of N-CDs sensitization and the highly ordered IOS, which make it a promising material to be used in clean energy, solar cells, potential applications in water purification and so on.

  14. Search for the Bc meson in hadronic Z0 decays using the OPAL detector at LEP

    Energy Technology Data Exchange (ETDEWEB)

    Herndon, Matthew Fairbanks [Univ. of Maryland, College Park, MD (United States)

    1999-01-01

    A search for decays of the Bc meson was performed using data collected from 1990--1995 with the OPAL detector on or near the Z0 peak at LEP. The decay channels B$+\\atop{c}$ → J/Ψπ+, B$+\\atop{c}$ → J/Ψa{sub 1}{sup +} and B$+\\atop{c}$ → J/Ψℓ+v were investigated, where ℓ denotes an electron or a muon. Two candidates are observed in the mode B$+\\atop{c}$ → J/Ψπ+, with an estimated background of (0.63 ± 0.20) events. The weighted mean of the masses of the two candidates is (6.32 ± 0.06) GeV/c2, which is consistent with the predicted mass of the Bc meson. One candidate event is observed in the mode B$+\\atop{c}$ → J/Ψℓ+v, with an estimated background of (0.82 ± 0.19) events. No candidate events are observed in the B$+\\atop{c}$ → J/Ψa$+\\atop{1}$ decay mode, with an estimated background of (1.10 ± 0.22) events. Upper bounds at the 90% confidence level are set on the production rates for these processes.

  15. Determination of $\\alpha_S$ using OPAL hadronic event shapes at $\\sqrt{s}$ = 91 − 209 GeV and resummed NNLO calculations

    CERN Document Server

    Abbiendi, G; Akesson, P F; Alexander, G; Anagnostou, G; Anderson, K J; Asai, S; Axen, D; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, R J; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, S; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; Dallavalle, M; De Roeck, A; De Wolf, E A; Desch, K; Dienes, B; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, F; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, J; Gruwe, M; Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Herten, G; Heuer, R D; Hill, J C; Horvath, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, D; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krasznahorkay, Jr A; Krieger, P; von Krogh, J; Kuhl, T; Kupper, M; Lafferty, G D; Landsman, H; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lu, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Mashimo, T; Mattig, P; McKenna, J; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; O’Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pasztor, G; Pater, J R; Pilcher, J E; Pinfold, J; Plane, D E; Pooth, O; Przybycien, M; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan, E K G; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schorner-Sadenius, T; Schroder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R; Soldner-Rembold, S; Spano, F; Stahl, A; Strom, D; Strohmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Trigger, I; Trocsanyi, Z; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvari, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, J; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2011-01-01

    Hadronic event shape distributions from e+e− annihilation measured by the OPAL experiment at centre-of-mass energies between 91 GeV and 209 GeV are used to determine the strong coupling αS. The results are based on QCD predictions complete to the next-to-next-to-leading order (NNLO), and on NNLO calculations matched to the resummed next-to-leading-log-approximation terms (NNLO+NLLA). The combined NNLO result from all variables and centre-of-mass energies is αS(mZ0) = 0.1201 ± 0.0008(stat.) ± 0.0013(exp.) ± 0.0010(had.) ± 0.0024(theo.). while the combined NNLO+NLLA result is αS(mZ0) = 0.1189 ± 0.0008(stat.) ± 0.0016(exp.) ± 0.0010(had.) ± 0.0036(theo.). The completeness of the NNLO and NNLO+NLLA results with respect to missing higher order contributions, studied by varying the renormalization scale, is improved compared to previous results based on NLO or NLO+NLLA predictions only. The observed energy dependence of αS agrees with the QCD prediction of asymptotic freedom and excludes the absence o...

  16. Annealing effect of fluorine-doped SnO2/WO3 core-shell inverse opal nanoarchitecture for photoelectrochemical water splitting

    Science.gov (United States)

    Cho, Seo Yoon; Kang, Soon Hyung; Yun, Gun; Balamurugan, Maheswari; Ahn, Kwang-Soon

    2017-01-01

    Fluorine-doped SnO2 inverse opal (FTO IO) was developed on a polystyrene bead template with a size of 350 nm (± 20 nm) by using the sol-gel-assisted spin-coating method. The resulting FTO IO film exhibited a pore diameter of 270 nm (± 5 nm), and a WO3 layer was electrodeposited with a constant charge of 400 mC/cm2, followed by a high-temperature annealing process (400, 475, and 550 °C) to increase the crystallinity of the IO films. The annealing temperature affected the morphology and the overall resistance of the thin film, thus significantly affecting the photoelectrochemical performance. In particular, the FTO/WO3 IO film annealed at 475 °C exhibited a photocurrent density of 2.9 mA/cm2 at 1.23 V versus normal hydrogen electrode, showing more than a three times higher photocurrent density in comparison with the other samples (550 °C), which is attributed to the large surface area and low resistance for the charge transport. Therefore, the annealing temperature significantly affects the morphological and the photoelectrochemical features of the FTO/WO3 IO films.

  17. Carbon-Coated Honeycomb Ni-Mn-Co-O Inverse Opal: A High Capacity Ternary Transition Metal Oxide Anode for Li-ion Batteries

    Science.gov (United States)

    McNulty, David; Geaney, Hugh; O’Dwyer, Colm

    2017-01-01

    We present the formation of a carbon-coated honeycomb ternary Ni-Mn-Co-O inverse opal as a conversion mode anode material for Li-ion battery applications. In order to obtain high capacity via conversion mode reactions, a single phase crystalline honeycombed IO structure of Ni-Mn-Co-O material was first formed. This Ni-Mn-Co-O IO converts via reversible redox reactions and Li2O formation to a 3D structured matrix assembly of nanoparticles of three (MnO, CoO and NiO) oxides, that facilitates efficient reactions with Li. A carbon coating maintains the structure without clogging the open-worked IO pore morphology for electrolyte penetration and mass transport of products during cycling. The highly porous IO was compared in a Li-ion half-cell to nanoparticles of the same material and showed significant improvement in specific capacity and capacity retention. Further optimization of the system was investigated by incorporating a vinylene carbonate additive into the electrolyte solution which boosted performance, offering promising high-rate performance and good capacity retention over extended cycling. The analysis confirms the possibility of creating a ternary transition metal oxide material with binder free accessible open-worked structure to allow three conversion mode oxides to efficiently cycle as an anode material for Li-ion battery applications. PMID:28186183

  18. Highly active surface-enhanced Raman scattering (SERS) substrates based on gold nanoparticles infiltrated into SiO2 inverse opals

    Science.gov (United States)

    Ankudze, Bright; Philip, Anish; Pakkanen, Tuula T.; Matikainen, Antti; Vahimaa, Pasi

    2016-11-01

    SiO2 inverse opal (IO) films with embedded gold nanoparticles (AuNPs) for surface-enhanced Raman scattering (SERS) application are reported. SiO2 IO films were loaded with AuNPs by a simple infiltration in a single cycle to form Au-SiO2 IOs. The optical property and the morphology of the Au-SiO2 IO substrates were characterized; it was observed that they retained the Bragg diffraction of SiO2 IO and the localized surface plasmon resonance (LSPR) of AuNPs. The SERS property of the Au-SiO2 IO substrates were studied with methylene blue (MB) and 4-aminothiophenol (4-ATP). The SERS enhancement factors were 107 and 106 for 4-ATP and MB, respectively. A low detection limit of 10-10 M for 4-ATP was also obtained with the Au-SiO2 IO substrate. A relative standard deviation of 18.5% for the Raman signals intensity at 1077 cm-1 for 4-ATP shows that the Au-SiO2 IO substrates have good signal reproducibility. The results of this study indicate that the Au-SiO2 IO substrates can be used in sensing and SERS applications.

  19. Search for a low mass CP-odd Higgs boson in $e^{+}e^{-}$ collisions with the OPAL detector at LEP2

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Elfgren, E.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kormos, Laura L.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kruger, K.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trefzger, T.; Tricoli, A.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2003-01-01

    We have analysed the data collected by OPAL at centre-of-mass energies between 189 and 209 GeV searching for Higgs boson candidates from the process e/sup +/e/sup -/ to h/sup 0/Z/sup 0/ followed by the decay of h/sup 0/ to A/sup 0/A/sup 0/ where A/sup 0/ is the CP-odd Higgs boson. The search is done in the region where the A/sup 0/ mass, m/sub A/, is below the production threshold for bb, and the CP- even Higgs boson mass m/sub h/ is within the range 45-86 GeV/c/sup 2 /. In this kinematic range, the decay of h/sup 0/ to A/sup 0/A/sup 0/ may be dominant and previous Higgs boson searches have very small sensitivities. This search can be interpreted within any model that predicts the existence of at least one scalar and one pseudoscalar Higgs boson. No excess of events is observed above the expected standard model backgrounds. Model-independent limits on the cross- section for the process e/sup +/e/sup -/ to h/sup 0/Z/sup 0/ are derived assuming 100% decays of the h/sup 0/ into A/sup 0/A/sup 0/ and 100% decays o...

  20. Marine biogeochemistries of Be and Al: A study based on cosmogenic 10Be, Be and Al in marine calcite, aragonite, and opal

    Indian Academy of Sciences (India)

    Weiquan Dong; Devendra Lal; Barbara Ransom; Wolfgang Berger; Marc W Caffee

    2001-06-01

    The geochemical behaviors of Be and Al in ocean waters have been successfully studied in recent years using natural, cosmogenic, radioactive 10Be and 26Al as tracers. The present day dissolved concentrations and distribution of the stable and radioactive isotopes of Be and Al in ocean waters have revealed their short residence times and appreciable effects of exchange uxes at the coastal and ocean-sediment interfaces. It follows that concentrations of these particle-active elements must have varied in the past with temporal changes in climate, biological productivity and aeolian ux of continental detritus to the oceans. We therefore investigated the feasibility of extending the measurements of Be and Al isotope concentrations in marine systems to the 103-106 BP time scale. We report here the discovery of significant amounts of intrinsic Be and Al in marine foraminiferal calcite and coral aragonite, and of Al in opal (radiolarians) and aragonite (coral), which makes it possible to determine 10Be/Be and 26Al/Al in oceans in the past. We also report measured 10Be/9Be in foraminiferal calcite in Pacific Ocean cores, which reveal that the concentrations and ratios of the stable and cosmogenic isotopes of Be and Al have varied significantly in the past 30 ky. The implications of these results are discussed.

  1. Au-modified three-dimensional In2O3 inverse opals: synthesis and improved performance for acetone sensing toward diagnosis of diabetes

    Science.gov (United States)

    Xing, Ruiqing; Li, Qingling; Xia, Lei; Song, Jian; Xu, Lin; Zhang, Jiahuan; Xie, Yi; Song, Hongwei

    2015-07-01

    Analyzing the volatile organic compounds (VOCs) in exhaled breath effectively is crucial to medical treatment, which can provide a fast and noninvasive way to diagnose disease. Well-designed materials with controlled structures have great influence on the sensing performance. In this work, the ordered three dimensional inverse opal (3DIO) macroporous In2O3 films with additional via-hole architectures were fabricated and different amounts of gold nanoparticles (Au NPs) were loaded on the In2O3 films aiming at enhancing their electrical responses. The gas sensing to acetone toward diabetes diagnosis in exhaled breath was performed with different Au/In2O3 electrodes. Representatively, the best 3DIO Au/In2O3 sensor can detect acetone effectively at 340 °C with response of 42.4 to 5 ppm, the actual detection limit is as low as 20 ppb, and it holds a dynamic response of 11 s and a good selectivity. Moreover, clinical tests proved that the as-prepared 3DIO Au/In2O3 IO sensor could distinguish acetone biomarkers in human breath clearly. The excellent gas sensing properties of the Au/In2O3 electrodes were attributed to the ``spillover effects'' between Au and In2O3 and the special 3DIO structure. This work indicates that 3DIO Au/In2O3 composite is a promising electrode material for actual application in the monitoring and detection of diabetes through exhaled breath.Analyzing the volatile organic compounds (VOCs) in exhaled breath effectively is crucial to medical treatment, which can provide a fast and noninvasive way to diagnose disease. Well-designed materials with controlled structures have great influence on the sensing performance. In this work, the ordered three dimensional inverse opal (3DIO) macroporous In2O3 films with additional via-hole architectures were fabricated and different amounts of gold nanoparticles (Au NPs) were loaded on the In2O3 films aiming at enhancing their electrical responses. The gas sensing to acetone toward diabetes diagnosis in exhaled

  2. 蛋白土负载型复合相变材料的制备与表征%Preparation and Characterization of Opal Loaded Composite Phase-change Materials

    Institute of Scientific and Technical Information of China (English)

    张殿潮; 孔维安; 郑水林; 刘月; 毛俊

    2013-01-01

      采用热熔复混法,以改性蛋白土为基体、石蜡为相变物质,制备出了具有合适相变温度、较大相变潜热的复合储能材料.采用SEM、红外光谱和差示扫描量热 DSC 对复合相变材料的结构和性能进行了表征,结果表明,制备的复合材料相变温度为24.91℃,相变潜热为64.31 J/g,颗粒均匀分布在蛋白土与熔融石蜡构成的基体之中;载体蛋白土和相变材料石蜡之间以分子间作用力的物理吸附结合,得到了稳定的复合相变材料.%Organic phase change materials like paraffin as phase change material, modified opal as carrier, composite phase change material with proper phase change temperature and larger phase change enthalpy is prepared by hot melt complex mixed. The structure and performance of composite phase material are characterized using SEM, infrared spectroscopy and synthesized thermal analyzer DSC. The results show that the phase change temperature of composite phase change materials is 24.91 ℃, and phase change enthalpy is 64.31 J/g. With every part preserved, phase change particles are distributed in the opal/melted paraffin matrix evenly. Stable composite phase change materials are prepared with opal as carrier and paraffin as PCMs, which are bonded with Vander Waals forces in the form of physical adsorption.

  3. The dynamic ocean biological pump: Insights from a global compilation of particulate organic carbon, CaCO3, and opal concentration profiles from the mesopelagic

    Science.gov (United States)

    Lam, Phoebe J.; Doney, Scott C.; Bishop, James K. B.

    2011-09-01

    We have compiled a global data set of 62 open ocean profiles of particulate organic carbon (POC), CaCO3, and opal concentrations collected by large volume in situ filtration in the upper 1000 m over the last 30 years. We define concentration-based metrics for the strength (POC concentration at depth) and efficiency (attenuation of POC with depth in the mesopelagic) of the biological pump. We show that the strength and efficiency of the biological pump are dynamic and are characterized by a regime of constant and high transfer efficiency at low to moderate surface POC and a bloom regime where the height of the bloom is characterized by a weak deep biological pump and low transfer efficiency. The variability in POC attenuation length scale manifests in a clear decoupling between the strength of the shallow biological pump (e.g., POC at the export depth) and the strength of the deep biological pump (POC at 500 m). We suggest that the paradigm of diatom-driven export production is driven by a too restrictive perspective on upper mesopelagic dynamics. Indeed, our full mesopelagic analysis suggests that large, blooming diatoms have low transfer efficiency and thus may not export substantially to depth; rather, our analysis suggests that ecosystems characterized by smaller cells and moderately high %CaCO3 have a high mesopelagic transfer efficiency and can have higher POC concentrations in the deep mesopelagic even with relatively low surface or near-surface POC. This has negative implications for the carbon sequestration prospects of deliberate iron fertilization.

  4. Measurement of the strangeness spectral function and the mass of the strange quark in hadronic {tau} decays with the OPAL detector

    Energy Technology Data Exchange (ETDEWEB)

    Mader, W.

    2004-03-01

    Tau lepton decays with open strangeness in the final state are measured with the Opal detector at LEP to determine the strange hadronic spectral function of the {tau} lepton and the mass of the strange quark. The decays {tau}{sup -} {yields} (K{pi}){sup -}{nu}{sub {tau}}, (K{pi}{pi}){sup -}{nu}{sub {tau}} and (K{pi}{pi}{pi}){sup -}{nu}{sub {tau}} with final states consisting of neutral and charged kaons and pions, have been studied. The invariant mass distribution of 93.4% of these final states have been experimentally determined. Monte Carlo simulations have been used for the remaining 6.6% and for the strange final states including {eta} mesons. The reconstructed strange final states, corrected for resolution effects and detection efficiencies, yield the strange spectral function of the {tau} lepton. The moments of the spectral function and the ratio of strange to non-strange moments, which are important input parameters for theoretical analyses, are determined. Furthermore, the branching fractions B({tau}{sup -} {yields} K{sup -}{pi}{sup 0}{nu}{sub {tau}}) = (0.471 {+-} 0.064{sub stat} {+-} 0.021{sub sys})%, B({tau}{sup -} {yields} K{sup -}{pi}{sup +}{pi}{sup -}{nu}{sub {tau}}) = (0.415 {+-} 0.059{sub stat} {+-} 0.031{sub sys})% have been measured. From the CKM weighted difference of strange and non-strange spectral moments, the mass of the strange quark at the {tau} mass scale has been determined: m{sub s}(m{sub {tau}}{sup 2}) = (84 {+-} 14{sub exp} {+-} 6{sub V{sub us}} {+-} 17{sub theo}) MeV. Evolving this result to customary scales yields m{sub s}(1 GeV{sup 2}) = (111{sub -35}{sup +26}) MeV, m{sub s}(4 GeV{sup 2}) = (82{sub -25}{sup +19}) MeV. (orig.)

  5. Behaviors of a MGPM/Opal Solid-Solid Phase-Change Storage Material%一种MGPM/Opal固-固相变储能材料的相变及结晶行为

    Institute of Scientific and Technical Information of China (English)

    顾晓华; 西鹏; 段玉情; 高芬; 刘剑虹

    2011-01-01

    A solid-solid phase change energy storage composite material with polyethylene glycol single methyl ether(MPEG) chain structure,which chould be abbreviated as MGPM/opal,was synthesized by the way of monomer polycondensation with phase change.Wide-angle X-ray diffraction(WAXD),differential thermal scanning calorimeter(DSC) and hot stage polarizing microscope(POM),thermogravimetry(TG) and other testing methods were performed to investigate the crystal structure,crystallization behaviors,crystalline morphology and thermal stability of the composite materials.The results indicate that the addition of natural nano-phase materials opal improves the crystallization behavior and increases the crystallization speed of MPEG.When the mass fraction of opal is 0.7%,the crystallinity of the copolymer is the highest,when the phase change enthalpy comes to 109.07 kJ/g.Compared to the pure MPEG,the melting enthalpy and the crystallization enthalpy of the copolymer increase by 10.578 J/g and 8 J/g,respectively.The thermal stability of the copolymer is good,and it increases with the increase of opal.%采用含有相变单元的单体缩聚法合成了侧链含有聚乙二醇单甲醚(MPEG)的新型固-固相变储能复合材料(相变共聚物缩写名称为(MGPM)/蛋白石(opal)),通过广角X射线衍射(WAXD)、差热扫描量热仪(DSC)和热台偏光显微镜(POM)、热重(TG)等测试手段对其结晶结构、结晶行为、结晶形态和热稳定性进行了研究,结果表明,天然纳米材料蛋白石的加入改善了MPEG的结晶行为,提高了聚合物的结晶速率。蛋白石的添加量为0.7%时可以最大程度提高聚合物的结晶度,相变焓值最高达到109.07 kJ/g,比纯MPEG的熔融焓值提高了10.578 J/g,结晶焓值提高了8 J/g,热稳定性良好。

  6. Preparation of high-quality large diameter polystyrene spheres opal by self-assembly method%大直径聚苯乙烯小球自组织方法制备高质量opal晶体

    Institute of Scientific and Technical Information of China (English)

    张琦; 孟庆波; 程丙英; 张道中

    2004-01-01

    通过改进样品池的结构和其他实验条件,用气压法制备了大直径聚苯乙烯小球(直径为1 μm和700 nm)的人造蛋白石(opal)样品,并测量了其能带特性.对于制备能带位置在红外波段的三维光子晶体,这一实验结果将有很广阔的用途.

  7. The isotopic composition of valves and organic tissue of diatoms grown in steady state cultures under varying conditions of temperature, light and nutrients. Implications for the interpretation of oxygen isotopes from sedimentary biogenic opal as proxies of environmental variations

    Energy Technology Data Exchange (ETDEWEB)

    Kowalczyk, K.

    2006-05-15

    The oxygen isotopes of diatomaceous silica from marine and freshwater sediments are frequently used as indicators of the palaeotemperature development, particularly in cases where calcareous microfossils are rare or absent. With regard to terrestrial waters it is unknown whether or not palaeotemperature scale can be used in a limnic ecosystem. Due to the fact that the seasonal variations in lakes are larger than in oceans, specific problems arise when working with freshwater sediments. Thus, an understanding of the contribution of the various factors (e.g. temperature, light nutrients, competition) influencing the formation of isotope signals in biogenic opal is a prerequisite for the accurate interpretation of environmental processes. Since it is impossible to examine the influence of a single parameter under natural ecosystem conditions due to permanent changes of the environment, laboratory experiments with single diatom species are needed. Therefore, the aim of this study was to investigate the correlation between the oxygen isotope variations in biogenic opal and different environmental parameters using steady state cultures with diatoms. It should be examined whether or not the different diatom species grown under identical conditions show equal oxygen isotope ratios (species relationship), if variations of the water temperature induce variations of the oxygen isotope ratio (relationship with temperature), variable parameters such as light intensity and nitrate concentration influence the isotope ratio, and if vital effects (e.g. growth rate) lead to variations of the oxygen isotope ratio. (orig.)

  8. Joint Effects of Photoactive TiO2 and Fluoride-Doping on SnO2 Inverse Opal Nanoarchitecture for Solar Water Splitting.

    Science.gov (United States)

    Gun, Yun; Song, Gwang Yeom; Quy, Vu Hong Vinh; Heo, Jaeyeong; Lee, Hyunjung; Ahn, Kwang-Soon; Kang, Soon Hyung

    2015-09-16

    Inverse opal (IO) films of tin dioxide (SnO2) were fabricated on polystyrene (PS) beads (diameter=350 nm (±20 nm) with a spin coating method. To compensate for the large band gap (Eg=3.8 eV), a thin TiO2 shell was deposited on the SnO2-IO films with atomic layer deposition (ALD), which produced shells with thicknesses of 10-40 nm. The morphological changes and crystalline properties of the SnO2 and TiO2-coated SnO2 (herein after referred to as TiO2/SnO2) IO films were investigated with field-emission scanning electron microscopy and X-ray diffraction, respectively. The photoelectrochemical (PEC) behavior of the samples was tested in a 0.1 M KOH solution under 1 sun illumination (100 mW/cm2 with an AM 1.5 filter). The highest PEC performance was obtained with the TiO2(10 nm)/SnO2 IO films, which produced a photocurrent density (Jsc) of 4.67 mA/cm2 at 0.5 V (vs NHE) and was sequentially followed by the TiO2(20 nm)/SnO2-IO, TiO2(30 nm)/SnO2-IO, TiO2 (40 nm)/SnO2-IO and SnO2 IO films. Overall, the thin TiO2 shell covered on the SnO2-IO core enhanced Jsc by 3 orders of magnitude, which in turn the PEC activity. This is mainly ascribed to the extremely low charge-transfer resistance (Rct) in the photoelectrode/electrolyte and at the TiO2/SnO2 interface, as well as the contribution of the photoactive TiO2 layer, which has an Eg of 3.2 eV. Moreover, to improve the electrical conductivity of the core SnO2 IO film, the films were doped with 10 mol % of F. The F- doped films were labeled as the FTO IO film. The Rct of the FTO-IO films decreased because of the improved electronic conductivity, enhancing the PEC performance of the TiO2(10 nm)/FTO-IO films by approximately 20%. The core-shell nanowire mesh nanoarchitecture is therefore suggested to provide an insight for designing the peculiar structure based on the material's properties and the engineering of their band gap energy for highly efficient PEC performance.

  9. Uranium-rich opal from the Nopal I uranium deposit, Peña Blanca, Mexico: Evidence for the uptake and retardation of radionuclides

    Science.gov (United States)

    Schindler, Michael; Fayek, Mostafa; Hawthorne, Frank C.

    2010-01-01

    The Nopal I uranium deposit of the Sierra Peña Blanca, Mexico, has been the focus of numerous studies because of its economic importance and its use as a natural analog for nuclear-waste disposal in volcanic tuff. Secondary uranyl minerals such as uranophane, Ca[(UO 2)(SiO 3OH)] 2(H 2O) 5, and weeksite, (K,Na) 2[(UO 2) 2(Si 5O 13)](H 2O) 3, occur in the vadose zone of the deposit and are overgrown by silica glaze. These glazes consist mainly of opal A, which contains small particles of uraninite, UO 2, and weeksite. Close to a fault between brecciated volcanic rocks and welded tuff, a greenish silica glaze coats the altered breccia. Yellow silica glazes from the center of the breccia pipe and from the high-grade pile coat uranyl-silicates, predominantly uranophane and weeksite. All silica glazes are strongly zoned with respect to U and Ca, and the distribution of these elements indicates curved features and spherical particles inside the coatings. The concentrations of U and Ca correlate in the different zones and both elements inversely correlate with the concentration of Si. Zones within the silica glazes contain U and Ca in a 1:1 ratio with maximum concentrations of 0.08 and 0.15 at.% for the greenish and yellow glazes, respectively, suggesting trapping of either Ca 1U 1-aqueous species or -particles in the colloidal silica. X-ray photoelectron spectroscopy (XPS), Fourier-transform infra-red spectroscopy (FTIR), and oxygen-isotope ratios measured by secondary-ion mass spectrometry (SIMS) indicate higher U 6+/U 4+ ratios, higher proportions of Si-OH groups and lower δ 18O values for the greenish silica glaze than for the yellow silica glaze. These differences in composition reflect increasing brecciation, porosity, and permeability from the center of the breccia pipe (yellow silica glaze) toward the fault (green silica glaze), where the seepage of meteoric water and Eh are higher.

  10. OPAL Netlogo Land Condition Model

    Science.gov (United States)

    2014-08-15

    estimate over- all training impact, may be used to estimate the number of “maneuver im- pact miles” ( MIMs ), the equivalent damage of one M1A2 traveling 1... MIM = maneuver impact mile V = vehicle type (Dimensionless) v = number of types of vehicles training in area for the week NumberV = number...generic indication of training intensity, quantified as the “average number of MIMs per training area,” which ranges from 1 to 3. Using methodologies

  11. Mesure de la Polarisation des Lambda Produits dans les Collisions Positron-Electron AU Lep a L'aide du Detecteur Opal

    Science.gov (United States)

    Vandenplas, Denis

    Le Modele Standard est le cadre theorique general qui, jusqu'a present, a permis l'interpretation de tous les resultats experimentaux en physique des hautes energies. Cette theorie decrit, entre autres, la production d'une paire de particules elementaires, formee d'un quark et d'un antiquark, a partir de la desintegration de l'un des bosons mediateurs de l'interaction faible, le Z^0. Cependant, dans ce cas precis, la transformation subsequente des quarks primaires en particules reelles, un processus appele hadronisation, n'est decrite qu'a l'aide de modeles phenomenologiques. Afin de sonder les mecanismes de l'hadronisation, cette these presente la mesure du transfert du spin d'un quark etrange primaire a une particule appelee Lambda lors des desintegrations hadroniques du Z^0. L'etude a ete realisee dans le cadre de la collaboration OPAL, une des quatre experiences menees au collisionneur LEP, la ou des electrons et des positrons sont acceleres jusqu'a une energie commune, sqrt{s} = {rm E_ {cm}}, voisine de l'energie de production du rm Z^0, M_{Z ^0} egale a 91.3 GeV. La theorie electrofaible precise la direction du spin, c'est-a-dire la polarisation, d'un quark etrange primaire provenant de la desintegration d'un Z ^0. Quant a lui, le modele des quarks etablit que l'orientation du spin d'un Lambda est directement reliee a la polarisation du quark etrange dont il provient. La question est de determiner dans quelle mesure la polarisation du quark primaire est transmise au Lambda a la suite du processus de l'hadronisation, decrit dans le cadre de la ChromoDynamique Quantique. Une estimation, qui tient compte de tous ces differents aspects theoriques, evalue a 30% la polarisation des Lambda dont l'impulsion est superieure a 15 GeV/c. La mesure experimentale de la polarisation repose sur l'identification des Lambda a partir de la reconstitution de la desintegration Lambdato ppi^-. Ce processus, qui se deroule par le biais de l'interaction faible, viole la parite car

  12. 一种添加蛋白石的固-固相变储能材料的制备及表征%Preparation and Characterization of Polyurethane (PU)/Opal Solid-Solid Phase Change Energy Storage Material

    Institute of Scientific and Technical Information of China (English)

    顾晓华; 西鹏; 沈新元

    2008-01-01

    利用天然纳米材料蛋白石(Opal)制备出新型有机-无机体系的聚氨酯/Opal固-固相变储能材料,并通过IR、1H-NMR、DSC、TG、POM、TEM等测试手段对其结构和性能进行表征分析.结果表明,该聚氨酯型相变材料具有较高的相变焓值、适宜的相变温度、热性能稳定和相变过程中不产生液体等特点.同时,加入天然纳米无机材料蛋白石后,结晶性能得到提高.

  13. 在单晶硅片上直接电化学沉积制备镍反opal光子晶体%Fabrication of Ni inverse opal photonic crystals on silicon wafer by electrodeposition

    Institute of Scientific and Technical Information of China (English)

    许静

    2012-01-01

    采用电化学沉积工艺直接向组装在单晶硅片上的聚苯乙烯胶体晶体中填充金属Ni,成功制备了Ni的反opal光子晶体.采用线性扫描伏安法研究了单晶硅表面的化学刻蚀对Ni的电化学沉积过程的影响,并采用扫描电子显微镜(SEM)、X射线衍射等对Ni反opal光子晶体的形貌和结构进行了观察分析,对其光学性能进行了初步研究.研究结果表明,对单晶硅片表面进行化学刻蚀有利于金属Ni的电化学沉积;在PS胶体晶体模板中电化学生长的金属Ni呈多晶状态,去除模板后形成了金属Ni的有序多孔结构.%Electrodeposition was used to fill the voids of PS colloidal crystals on silicon wafer with Ni and Ni inverse opal was obtained. The influence of chemical etching of silicon wafer on the electrodeposition of Ni was studied by using cyclic voltammetry scan. The resulted Ni inverse opal was characterized by scanning electron microscopy and X-ray diffraction. It showed that chemical etching of silicon surface is beneficial for the deposition of Ni on silicon wafer. Ni grown in the voids of PS colloidal crystals is the polycrystalline phase and the ordered porous structure of Ni is formed after the removing of the PS template.

  14. Study on the Mineralogical and Optical Characteristics of Blue Opal from Lishui Investigated by XRF-SEM-XRD-FTIR%应用XRF-SEM-XRD-FTIR等分析测试技术研究丽水蓝色类欧泊(蛋白石)的矿物学与光学特征

    Institute of Scientific and Technical Information of China (English)

    严俊; 胡仙超; 方飚; 陶金波; 彭秋瑾; 张俭

    2014-01-01

    Opal deposits and their corresponding mineralogical characteristics are rarely reported in China as far as can be ascertained.In the end of 201 3,a type of blue quasi-opal deposit was discovered in Jinyun,Lishui, Zhejiang Province,which has attracted the gem researchers.While the related investigation about this blue quasi-opal has not been reported,in this paper,the mineralogical and optical characteristics of blue quasi-opal collected from Jinyun,Zhejiang Province are carried out primarily by X-ray Fluorescence Spectrometry (XRF ),Field Emission-Scanning Electron Microscopy (FE-SEM),X-ray Powder Diffraction (XRD)and Fourier Transformation Infrared Spectroscopy (FTIR).The results show that the main compositions of blue quasi-opal mineral are silica (95%)and a small amount of Fe2 O3 and Al2 O3 .Meanwhile,an iridescent effect is found on the surface of both unheated and heated samples,which resembles those of natural opals.The XRD spectra with sharp diffraction peak are consistent with those of cristobalite,which is obviously different from some microcrystalline opals (such as Opal-CT,Opal-C)and amorphous opals (Opal-A).In addition,its infrared spectrum shows a typical frequency shift compared with natural opals.As a consequence,these blue ores are preliminary classified as quasi-opals and named as a variant of volcanic-type opals since the geological structure of Jinyun area has the characteristics of Mesozoic volcanic rocks.Based on FE-SEMinvestigation,the iridescent effect is attributed to imbricate structure on ore surface.Further research is needed to confirm their exact category.%直至目前,我国相关欧泊的矿藏及其相应的矿物学特征鲜见报道,2013年末在浙江丽水缙云地区发现的蓝色类欧泊石引起了宝玉石科研工作者的广泛关注,但此矿物的相关研究至今尚未见论述。本文应用X射线荧光光谱(XRF )、场发射扫描电镜(FE-SEM)结合X射线粉晶衍射(XRD)与傅里叶变换

  15. Production of protons in the decay of Z{sup 0} measured by means of OPAL detector at LEP storage ring; Production de protons dans la desintegration de Z{sup 0} mesuree a l'aide du detecteur OPAL au LEP

    Energy Technology Data Exchange (ETDEWEB)

    Malik, A

    1997-09-01

    From the data samples accumulated from 1991 to 1994 by the OPAL detector during the first phase of operation at LEP, the proton production rates are measured with the help of the time-of-flight (TOF) detector. A method is developed for the measurement of the pion and proton production rates with the velocity spectra. The velocity is calculated from the time-of-flight measurement. This method offers the best results in the momentum range from 0.8 to 1.8 GeV/c. This range gives inclusive rates of 4.09 {+-} 0.01 {+-} 0.28 pions and 0.227 {+-} 0.002 {+-} 0.019 protons per event. This method is then adapted to 3-jet events by using the E0 jet-finder with a y{sub cut} of 0.03 to separate the jets. After regrouping the jets by their energy, the proton rates are calculated as a function of track momentum and jet energy. Dividing the rates by the jet charged multiplicity leads to relative rates that have less of an energy dependence than absolute rates. The relative rates in the measured momentum range are converted to R{sub pp}-bar, the rates for the total momentum range, by a factor calculated with the Monte Carlo. After fitting R{sub pp}-bar{sup gluon} and R{sub pp}-bar{sup quark}, their ratio, R{sub pp}-bar{sup gluon}/R{sub pp}-bar{sup quark}, is 0.971 {+-} 0.019 (stat){sub -0.090}{sup +0.099} (sys) for the fit between 5 and 45 GeV and 1.054 {+-} 0.027 (stat){sub -0.094}{sup +0.102} (sys) for the fit between 5 and 40 GeV. The relatively high value of R{sub pp}-bar in the last energy bin decreases the ratio R{sub pp}-bar{sup gluon}/R{sub pp}-bar{sup quark}. On the other hand, the ratio obtained by the values from the fit without the last bin is in agreement with the results from other analyses. (author)

  16. CdS沉积次数对TiO2反Opal膜电极光电性能的影响%Influence of CdS CBD Cycles on the Photoelectric Performance of TiO2 Inverse Opal Electrode

    Institute of Scientific and Technical Information of China (English)

    邓小彬; 王爱军; 陈胜利; 王晓东; 赵昆; 李志亮

    2013-01-01

    本文以单分散聚苯乙烯(Polystyrene,简写为PS)微球为模板颗粒,采用室温漂浮自组装法组装了PS opal模板,然后用液相沉积技术填充、去除模板制备了TiO2反opal膜,最后采用化学浴沉积法(Chemistry Bath Deposition,简写为CBD)在TiO2反opal膜上沉积CdS量子点.以CdS量子点敏化的TiO2反opal膜为光阳极组装太阳能电池并测试其光电性能.实验结果表明:CBD沉积CdS量子点次数对TiO2反opal膜电极的光电性能有影响.在本文实验条件下,当CBD沉积次数为5次时,CdS量子点敏化的TiO2反opal膜电极的太阳能电池具有最高光电转化效率.%In this paper, the polystyrene (PS) opal templates were fabricated using floating self-assembly method at room temperature, and then TiO2 inverse opal films were fabricated by filling and removing the PS opal templates through a liquid-phase deposition ( LPD) technique. The TiO2 inverse opal films sensitized with CdS quantum dots by chemical bath deposition( CBD) method were as the anodes of solar cells. The effects of CBD cycles on photovoltaic properties of CdS quantum-dots-sensitized solar cells were investigated. The results showed that the conversion efficiency of the solar energy to electricity energy was the highest when CdS CBD cycles was 5.

  17. Forêt et conservation des dunes littorales : le cas exemplaire de la Réserve biologique domaniale de la Côte d'Opale (Pas-de-Calais

    Directory of Open Access Journals (Sweden)

    Yves Petit-Berghem

    2012-02-01

    Full Text Available La Réserve biologique domaniale de la Côte d’Opale représente en France l’un des rares systèmes dunaires marqués par la libre expression des processus dynamiques. La mobilité du site garantit le renouvellement et la diversité des biotopes et donc des habitats et des espèces qui leur sont associées. Comme toute réserve, il s’agit d’un espace réglementé où les actions de gestion sont orientées dans un sens conservatoire et strictement contrôlées. La difficulté des gestionnaires est aujourd’hui de définir un objectif à plus long terme de cette réserve. Quelles sont les structures partenaires à privilégier ? Quel degré d’ouverture au public ? Quelles sont les pistes de recherche à développer ? Comment concilier une politique de conservation écologique avec un développement durable du territoire ? Ces différents questionnements appellent une réflexion entre nature et société et renvoient à la gouvernance des territoires et à la place de l’homme dans son environnement.The coastal dunes of the Pas-de-Calais area (dunes of Berck-Merlimont with the « Réserve biologique domaniale de la Côte d’Opale », northwest France is one of the few dune systems in France characterized by the free expression of dynamic processes. The mobility of the site ensures the renewal and diversity of dune environments and thus habitats and species associated with them. Like any reserve, it is a regulated area where management actions are oriented in one direction (conservation management and strictly controlled. The challenge for managers today is to define a longer-term objective of this reserve. What are the working partners for which it would be possible to collaborate? What degree of openness to the public? What are the research topics to develop? How to reconcile a policy of environmental conservation with sustainable territorial development? These questions require a discussion between nature and society and

  18. EFFECT OF OPAL APPLICATION IN DIFFERENT GROWTH STAGES ON GROWTH AND DEVELOPMENT OF SUMMER SOYBEAN%不同生育期施用"奥普尔"对夏大豆生长发育的影响

    Institute of Scientific and Technical Information of China (English)

    夏桂平; 王安祥; 叶西阔; 朱传军; 韩年胜

    2000-01-01

    Soybean germination rate may be increased to 9. 1% through soil treated withOpal liquid fertilizer. The plant height and 100 seed-weight reduced and the number ofbranches and pods were increased by applying Opal liquid fertilizer during the growing periodexcept for pod filling stage. There was no change of plant height and number of branchesand but number of pods was reduced and the number of seeds per pod and 100 seed-weightwere raised by applying the fertilizer in the stage of pod filling. The result indicated that thenumber of seed per plant, yield and economic benefit may be enhanced by using of the fertil-izer. The yield increased 11.8 % and 9. 6 % respectively when the fertilizer was applied insoil before seeding and sprayed in the flowering stage, and the yield increased 13.6% whenthose two fertilizer treatments were applied in soybean growth period.%用奥普尔液肥处理土壤,可提高大豆出苗率9.1%。除鼓粒期外,其余生育期使用该液肥,株高降低,分枝数增加,株英数增加,百粒重降低;而鼓粒期施用,株高、分枝数没有变化,株英数减少,英粒数和百粒重增加。综合效果:大豆施用奥普尔液肥,株粒数增加,产量提高,经济效益提高。而以土壤处理和花期喷施效果最好,增产率分别达11.8%和9.6%;两次复加施用,增产率达13.6%,投入产出比达1:5.3。

  19. NaYF4:Yb,Tm nanocrystals and TiO2 inverse opal composite films: a novel device for upconversion enhancement and solid-based sensing of avidin

    Science.gov (United States)

    Xu, Sai; Xu, Wen; Wang, Yunfeng; Zhang, Shuang; Zhu, Yongsheng; Tao, Li; Xia, Lei; Zhou, Pingwei; Song, Hongwei

    2014-05-01

    Upconversion luminescence (UCL) detection based on rare-earth doped upconversion nanocrystals (UCNCs) as probes has been proved to exhibit a large anti-Stokes shift, no autofluorescence from biological samples, and no photobleaching. However, it is still a challenge to achieve a stable, reproducible solid-based UCL biosensor because of ineffective UCL of the UCNCs. In this work, we fabricated TiO2 inverse opal photonic crystals (IOPCs)/NaYF4:Yb3+,Tm3+ (Er3+) UCNC composite films, which can tremendously improve the overall UCL of Tm3+ as high as 43-fold. Based on the fluorescence resonance energy transfer (FRET) and the specific interaction between biotin and avidin, a novel solid-based UC biosensor is presented for sensing avidin. This solid-based detection system is convenient for detection, and also can offer two parameters for detecting trace amounts of avidin, namely, the emission intensity and the fluorescence decay time. The sensor has a high sensitivity of 34 pmol-1, a good linear relationship of 0.996 and a low detection limit of 48 pmol. It also exhibits excellent long-time photostability, and the absence of autofluorescence, and thus may have great potential for versatile applications in biodetection.

  20. Production of D* mesons in photon-photon collisions at $\\sqrt{s}_{ee}$ = 183 GeV and 189 GeV using the OPAL detector at LEP

    CERN Document Server

    Patt, J

    2000-01-01

    The inclusive production of D*/sup +or-/ mesons in photon-photon collisions has been measured using the OPAL detector at LEP at e/sup +/e/sup -/ centre-of-mass energies square root (s/sub ee/) of 183 and 189 GeV. The D*/sup +/ mesons are reconstructed in their decay to D /sup 0/ pi /sup +/ with the D/sup 0/ observed in the two decay modes K/sup -/ pi /sup +/ and K/sup -/ pi /sup +/ pi /sup -/ pi /sup +/. After background subtraction, 121+or-14 (stat.) D*/sup +or-/ events have been selected. Jets are reconstructed using a cone jet finding algorithm to separate direct and single-resolved events. Differential cross-sections d sigma /dp/sub T//sup D/* and d sigma /d eta /sup D /* as functions of the D*/sup +or-/ transverse momentum p/sub T//sup D/* and pseudorapidity eta /sup D/* are presented in the kinematic region 2

  1. Soft-template construction of three-dimensionally ordered inverse opal structure from Li2FeSiO4/C composite nanofibers for high-rate lithium-ion batteries

    Science.gov (United States)

    Li, Donglin; Zhang, Wei; Sun, Ru; Yong, Hong-Tuan-Hua; Chen, Guangqi; Fan, Xiaoyong; Gou, Lei; Mao, Yiyang; Zhao, Kun; Tian, Miao

    2016-06-01

    Exploring a new method to fabricate small-sized nanofibers is essential to achieve superior performances for energy conversion and storage devices. Here, a novel soft-template strategy is developed to synthesize a three-dimensionally ordered macroporous (3DOM) architecture constructed from small-sized nanofibers. The effectiveness of a nanofiber-assembled three-dimensional inverse opal material as an electrode for high-rate lithium-ion batteries is demonstrated. The small-sized Li2FeSiO4/C composite nanofibers with a diameter of 20-30 nm are grown by employing a tri-block copolymer P123 as a structure directing agent. Accordingly, the macro-mesoporous hierarchical 3DOM architecture constructed from Li2FeSiO4/C nanofibers is further templated from P123 for the nanofibers and a polystyrene colloidal crystal array for the 3DOM architecture. We find that the thermal stability of the nanofiber morphology depends on the self-limited growth of Li2FeSiO4 nanocrystals in a crystalline-amorphous hybrid. As a cathode for a lithium-ion battery, the 3D hierarchical macro-mesoporous cathodes exhibit outstanding high-rate and ultralong-life performances with a capacity retention of 84% after 1500 cycles at 5 C in the voltage window of 1.5-4.5 V, which is greatly improved compared with a simple 3DOM Li2FeSiO4/C nanocomposite.Exploring a new method to fabricate small-sized nanofibers is essential to achieve superior performances for energy conversion and storage devices. Here, a novel soft-template strategy is developed to synthesize a three-dimensionally ordered macroporous (3DOM) architecture constructed from small-sized nanofibers. The effectiveness of a nanofiber-assembled three-dimensional inverse opal material as an electrode for high-rate lithium-ion batteries is demonstrated. The small-sized Li2FeSiO4/C composite nanofibers with a diameter of 20-30 nm are grown by employing a tri-block copolymer P123 as a structure directing agent. Accordingly, the macro

  2. Efficient energy transfer from inserted CdTe quantum dots to YVO₄:Eu³⁺ inverse opals: a novel strategy to improve and expand visible excitation of rare earth ions.

    Science.gov (United States)

    Zhu, Yongsheng; Cui, Shaobo; Chen, Xu; Xu, Wen; Zhou, Pingwei; Wang, Yunfeng; Xu, Lin; Song, Hongwei; Huang, Ling; Huang, Wei

    2014-07-21

    Rare earth (RE)-based phosphors demonstrate sharp emission lines, long lifetimes and high luminescence quantum yields; thus, they have been employed in various photoelectric devices, such as light-emitting diodes (LEDs) and solar spectral converters. However, their applications are largely confined by their narrow excitation bands and small absorption cross sections of 4f-4f transitions. In this paper, we demonstrate a novel strategy to improve and expand the visible excitation bands of Eu(3+) ions through the interface energy transfer (ET) from CdTe quantum dots (QDs) to YVO₄:Eu(3+) inverse opal photonic crystals (IOPCs). The significant effects observed in the CdTe QDs/YVO₄:Eu(3+) IOPCs composites were that the excitation of Eu(3+) ions was continuously extended from 450 to 590 nm and that the emission intensity of the (5)D₀-(7)FJ transitions was enhanced ∼20-fold, corresponding to the intrinsic (7)F₁-(5)D₁ excitation at 538 nm. Furthermore, in the IOPC network, the ET efficiency from the QDs to YVO₄:Eu(3+) was greatly improved because of the suppression of energy migration among the CdTe QDs, which gave an optimum ET efficiency as high as 47%. Besides, the modulation of photonic stop bands (PSBs) on the radiative transition rates of the QDs and Eu(3+) ions was studied, which showed that the decay lifetime constants for Eu(3+) ions were independent of PSBs, while those of QDs demonstrated a suppression in the PSBs. Their physical nature was explained theoretically.

  3. 澳洲的瑰宝OPAL

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    欧泊是宝石的一种.英文名为“OPAL”.源自希腊文“OPALLOS”,意思是颜色变幻。欧泊是由微小的氢氧化硅圆球(Hydrated Silica)组成,圆球之间充满着矽和水的混合物硅凝胶。

  4. Fabrication of silicon inverse opal photonic crystal with a complete photonic band gap in mid infrared range and its optical properties%中红外完全带隙Si反蛋白石光子晶体的制备与光学性能研究

    Institute of Scientific and Technical Information of China (English)

    李宇杰; 谢凯; 许静; 李效东; 韩喻

    2010-01-01

    通过溶剂蒸发对流自组装法制备SiO_2胶体晶体,采用低压化学气相沉积法填充Si,制备得到Si反蛋白石(opal)三维光子晶体.采用扫描电子显微镜对Si反opal的显微形貌进行表征,采用平面波展开法理论模拟Si反opal的光子带隙,采用傅里叶变换红外光谱仪测试其光学性能.研究结果表明:Si在SiO_2微球空隙内填充致密均匀,显微红外光谱测试的光子带隙反射峰位置及带宽与理论计算基本符合.变角度反射光谱测试表明,Si反opal沿不同角度入射时在中心波长3319 nm处均存在明显的反射峰,证明其具有完全光子带隙,带隙位于中红外大气窗口区域.

  5. NaGd(WO4)2∶Yb3+/Tm3+反蛋白石光子晶体的制备与上转换发光调制研究%Preparation and Modified Upconversion Luminescence In NaGd(WO4)2∶Yb3+/Tm3+ Inverse Opal Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    王运锋; 宋金璠; 唐晓燕; 胡冬梅

    2016-01-01

    Photonic crystal (PC) possesses long-scale periodicity and has been widely applied in modifying visible and near-infrared photonic band gap.One of the extraordinary properties of the PCs is the modulation on spontaneous emis sion of embedded luminescence centers.In this study,three-dimensional NaGd (WO4)2∶yb3+/Tm3+ inverse opal photonic crystals (IOPC) with highly oridered periodic structure were prepared by self-assembly method using PMMA as template.The modulation effect of PC on emission spectra and dynamics of Tm3+ ions were systemically studied.In NaGd (WO4)2∶yb3+/Tm3+ inverse opal photonic crystals,due to unique cavity structure and photonic band gap effect,the emission line of 1G4-3H6 transition decreases by ~45% and the spontaneous radiation rate is suppressed by ~30%.Meanwhile,the up-conversion local thermal effect is largely suppressed.This experimental analysis indicates that the IOPC structure is an effective device for improving efficiency of up-conversion luminescence.%三维光子晶体具有长程有序的结构特点,在可见和近红外光谱范围内有着广泛的应用.光子晶体的一个重要性质是其对嵌入其中的发光中心自发辐射具有调制作用.本研究利用自组装和模板辅助法制备高质量的三维NaGd(WO4)2∶Yb3+/Tm3+反蛋白石光子晶体,探究了光子带隙对Tm3+离子上转换荧光发射与发光动力学的调制作用.通过对比分析发现,由于反蛋白石光子晶体独特的周期性大孔结构和光子带隙效应,处于光子带隙内的Tm3+离子1G4-3H6的发光强度被抑制约45%,自发辐射速率(SDR)被抑制约30%,同时上转换局域热效应得到有效的调制.本实验结果对探索新型高效稀土掺杂上转换发光材料和提高上转换发光效率有指导意义.

  6. Les Cahiers du Littoral, Unité de Recherche sur l’Histoire, les Langues, les Littératures et l’Interculturel (H.L.L.I. de l’Université du Littoral Côte d’Opale, Aachen, Shaker Verlag, No. 7 / 2010

    Directory of Open Access Journals (Sweden)

    Speranţa Sofia MILANCOVICI

    2012-01-01

    Full Text Available Colectivul editorial al caietelor publicate de către unitatea de cercetare în domeniul istoriei, limbilor străine, literaturilor şi interculturalităţii, din cadrul Universităţii Littoral Côte d’Opale, propune, pentru fiecare număr, o tematică incitantă şi de actualitate. Aducem în discuţie subiectul numărului 7/2010, Technique et éthique : le défi de la culture à la nature, volum care pune în discuţie modul în care progresul tehnic se raportează la ideea de etică.Pornind de la consideraţia potrivit căreia tehnica a fascinat mereu fiinţa umană, aceasta din urmă ajungând, în contemporaneitate, să trăiască într-o tehnosferă care îl îndepărtează de nevoile sale fundamentale, veritabile, autorii studiilor abordează această problemă din multiple perspective, specifice ariilor individuale de competenţă.Aşadar, profilul de ansamblu al acestui număr este unul pluridisciplinar.Fireşte, opoziţia artă-industrie a focalizat de-a lungul vremii energiile analitice ale specialiştilor. Insă acum, în era globalizării, a comunicării superficiale şi inegale (în studiul său dedicat problemei etice în tehnologiile informaţiei, cercetătoarea Odile Riondet notează faptul că, potrivit unui raport UNESCO, în zona Manhattan există mai multe telefoane decât în întreaga Africă Neagră acest raport trebuie reevaluat.

  7. Effect of Fe doping on the photocatalytic activity of titania inverse opal under visible light irradiation%铁掺杂钛基反蛋白石材料的性能表征及其可见光催化活性

    Institute of Scientific and Technical Information of China (English)

    马伊; 付纪文; 郑言贞; 陶霞; 陈建峰

    2011-01-01

    采用溶胶凝胶法制备了不同掺杂比的铁掺杂二氧化钛反向蛋白石结构材料,通过扫描电镜,X射线能谱及紫外可见分光光度仪等对掺杂前后的样品进行比较,并采用罗丹明-B作为降解底物,对掺杂后样品在可见光下的光催化降解活性进行了研究.结果表明,铁掺杂后,样品的吸收带边发生红移,光响应区域扩展至550 nm,且样品中表面羟基氧的含量最高可提高到40%.铁掺杂样品的催化活性明显优于未掺杂的样品,其中掺杂比为10%的样品光催化降解活性最高,经可见光照射4 h后,其降解率可达85%以上.%Fe-doped titania inverse opal (TIO) materials with different doping ratios have been prepared by a solgel method. The products were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis spectroscopy. By using Rhodanmine-B as a model pollutant, the effects of Fe doping on the photocatalytic activity under visible irradiation were studied. The results indicated that the presence of Fe induced a red-shift of the absorption edge, as a result of which the photoresponse region was extended to 550 nm. In addition, Fe doping resulted in an increase in the content of surface hydroxyl group on the TiO2 surface of up to 40%. The photodegradation experiments showed that the visible photocatalytic activity of Fe-doped TIO is superior to that of the undoped sample. The 10% Fe-doped TIO exhibited the highest efficiency, giving a degradation extent of 85% under visible light irradiation for 4 hours.

  8. Higgs boson searches at OPAL (LEP), ATLAS (LHC) and ILC

    CERN Document Server

    AUTHOR|(CDS)2074372; Duchovni, Ehud

    2006-01-01

    An impressive effort was done by the four LEP collaborations in the search for the SM and the MSSM Higgs boson. However, very little attention was paid to the possibility of a CP violating Higgs sector and no significant effort to search for the resulting signatures was carried out. Once the CP state of the neutral Higgs bosons is ill defined, new Higgs boson production and decay channels might be opened. One of them, $\\epm\\ra\\Zo\\Htwo\\ra\\Zo\\Hone\\Hone\\ra\

  9. A New Neutron Radiography / Tomography / Imaging Station DINGO at OPAL

    Science.gov (United States)

    Garbe, U.; Randall, T.; Hughes, C.; Davidson, G.; Pangelis, S.; Kennedy, S. J.

    A new neutron radiography / tomography / imaging instrument DINGO was built to support the area of neutron imaging research (neutron radiography/tomography) at ANSTO. The instrument is designed for an international user community and for routine quality control for defense, industrial, cultural heritage and archaeology applications. In the industrial field it provides a useful tool for studying cracking and defects in steel or other metals. The instrument construction was completed at the end of June 2013 and it is currently in the hot commissioning stage. The usable neutron flux is mainly determined by the neutron source, but it depends on the instrument position and the resolution. The instrument position for DINGO is the thermal neutron beam port HB-2 in the reactor hall. The measured flux (using gold foil) for an L/D of approximately 500 at HB-2 is 5.3*107 [n/cm2s], which is in a similar range to other facilities. A special feature of DINGO is the in-pile collimator position in front of the main shutter at HB-2. The collimator offers two pinholes with a possible L/D of 500 and 1000. A secondary collimator separates the two beams by blocking one and positions another aperture for the other beam. The whole instrument operates in two different positions, one for high resolution and one for high speed. In the current configuration DINGO measured first radiography and tomography data sets on friendly user test samples.

  10. Hadronic decays of the Z sup 0 boson: Jet physics and tests of QCD with OPAL

    Energy Technology Data Exchange (ETDEWEB)

    Bethke, S. (Physikalisches Inst., Univ. Heidelberg (Germany))

    1991-08-01

    Several QCD plus hadronisation models are compared to measured event shape distributions and the model parameters are adjusted to the data. QCD shower models provide a detailed description of hadronic Z{sup 0} decays and, with the smae model parameters, of lower energy e{sup +}e{sup -} annihilation data as well. The momentum spectra of charged particles are consistent with the expectations of soft gluon coherence and Local Parton Hadron Duality. From a measurement of jet production rates, the strong coupling constant is determined to be, in second order perturbation theory, {alpha}{sub s}(M{sub Z})=0.116{+-}0.016. Jet production rates and 4-jet angular correlations provide evidence for the running of {alpha}{sub s} and for the nonabelian structure of QCD. (orig.).

  11. Unconventional optical Tamm defect states in metal-terminated opal photonic crystals

    Science.gov (United States)

    Korovin, Alexander V.; Romanov, Sergei G.

    2016-04-01

    Optical Tamm surface states are formed in 3-dimensional photonic crystals coated by thin metal films. These states appear in registry with diffraction resonances and localize the electromagnetic energy in resonators formed by diffraction mirrors of lattice planes and metal semishells. Tamm defect states provide the bypass for light in the spectral range of photonic stop-bands and thus reduce the efficiency of the Bragg diffraction resonances. In spite of hidden nature of this effect, its magnitude is comparable to the extraordinary transmission associated with tunneling of surface plasmon polaritons, which are simultaneously excited at surfaces of corrugated metal film coating.

  12. Photon-phonon anti-stokes upconversion of a photonically, electronically, and thermally isolated opal

    Science.gov (United States)

    Stem, Michelle R.

    2016-05-01

    The purpose of the present research was to investigate an intense violet shift displayed by a non-toxic, natural silicate material with a highly ordered nanostructure. The material displayed an unexpected, nonlinear 2:3 photon-phonon anti-Stokes upconversion while photonically, electronically, and thermally isolated. Conducted aphotonically and at ambient temperatures, the specimen upconverted a low-power, 650 nm constant wave red laser to an internally highly dispersed 433 nm violet wavelength. The strong dispersion was largely due to nearly total internal reflection of the laser. The upconversion had an efficiency of about 78 %, based on specimen volume, with no detectable thermal variance. The 2:3 anti-Stokes upconversion displayed by this material is likely the result of a previously unknown photon-phonon evanescence response that amplified the energy of a portion of the incident laser photons. Thus, a portion of the incident laser photons were upconverted, and the material converted another portion into an amplified energy that caused the upconversion. Internal micro-lasing appeared to be a means of photon-phonon evanescent energy redistribution, enabling dispersed photonic upconversion. Additional analyses also found an unexpectedly rhythmic photonic structure in spectrophotometric scans, polariscopic color changing, and previously undocumented ultraviolet responses.

  13. Investigations of properties of opal-like photonic crystals using combined methods

    Science.gov (United States)

    Akhmadeev, A. A.; Salakhov, M. Kh

    2016-05-01

    We propose a technique that combines atomic force microscopy, optical spectrophotometry and diffraction method for characterization of photonic crystals. These materials are promising for the creation of various devices, as well as for the observation of new effects due to their unique properties. Photonic crystals were synthesized by self-assembly of colloidal silica particles with low deviation in size. It is shown that the developed technique allows to increase the accuracy of determining the parameters of the photonic crystal.

  14. Simulation of dental microwear: Characteristic traces by opal phytoliths give clues to ancient human dietary behavior.

    Science.gov (United States)

    Gügel, I L; Grupe, G; Kunzelmann, K H

    2001-02-01

    In order to further evaluate the process of microwear formation on human dental enamel, microwear was experimentally produced by a chewing simulation with an Academic Center for Dentistry Amsterdam (ACTA) device. For this simulation, several cereal species were processed according to historical milling techniques, the experimental results of which were compared with those obtained from cereals processed after modern techniques, and also with natural microwear on early medieval human molars. Comparison of simulated microwear pits with natural microwear pits showed that the simulation led to traces which matched those found on the historical teeth in terms of both size and shape. Experimentally produced microwear pits were especially characteristic for the cereal species used in the simulations, and both pit morphology and enamel loss were a function of cereal phytolith content. Despite the high variability of phytolith size and shape, certain types are characteristic for certain cereals, which in turn are capable of producing cereal-specific microwear. This experimental approach is likely to further define ancient human dietary behavior, including food processing. Copyright 2001 Wiley-Liss, Inc.

  15. Observations of defect propagation in [100]-oriented opal-type photonic crystals

    Institute of Scientific and Technical Information of China (English)

    Jin Chong-Jun; Richard M. De La Rue; Nigel P. Johnson

    2008-01-01

    Charged colloidal suspensions have been used as experimental models for the study of crystal nucleation. Here we propose that the technique of template-assisted colloidal self-assembly can be used to visualize the effects of defect propagation in atomic crystal films produced using epitaxial growth. Templates with periodic line defects were used to grow [100]-oriented three-dimeusional photonic crystals by means of the template-assisted colloidal self-assembly method,aided by capillary and gravitational forces. The defect propagation in the [100J-oriented photonie crystal was observed using scanning electron microscopy, both at the surface of the crystal and on cleaved facets. This method is useful in the understanding of defect propagation in the growth of colloidal films on templates - and the same approach may also prove useful for the understanding of atomic crystal growth on substrates with defects. Additionally, the deliberate incorporation of line defects may prove valuable as a way of introducing waveguide channels into three-dimensional photonic crystals.

  16. Using public participation to sample trace metals in lake surface sediments: the OPAL Metals Survey.

    Science.gov (United States)

    Turner, S D; Rose, N L; Goldsmith, B; Bearcock, J M; Scheib, C; Yang, H

    2017-05-01

    Members of the public in England were invited in 2010 to take part in a national metals survey, by collecting samples of littoral sediment from a standing water body for geochemical analysis. To our knowledge, this is the first national sediment metals survey using public participation and reveals a snapshot of the extent of metals contamination in ponds and lakes across England. Hg, Ni, Cu, Zn and Pb concentrations exceeding sediment quality guidelines for the health of aquatic biota are ubiquitous in ponds and lakes, not just in areas with a legacy of industrial activity. To validate the public sampling approach, a calibration exercise was conducted at ten water bodies selected to represent a range of lakes found across England. Sediment concentrations of Hg, Ni, Cu, Zn and Pb were measured in samples of soil, stream and littoral and deep water sediment to assess inputs. Significant differences between littoral sediment metal concentrations occur due to local variability, but also organic content, especially in upland, peat soil catchments. Variability of metal concentrations between littoral samples is shown to be low in small (metal contamination in standing waters. However, the heterogeneity of geology, soils and history/extent of metal contamination in the English landscape, combined with the random nature of sample collection, shows that systematic sampling for evaluating the full extent of metal contamination in lakes is still required.

  17. Understanding anisotropic plasma etching of two-dimensional polystyrene opals for advanced materials fabrication.

    Science.gov (United States)

    Akinoglu, Eser M; Morfa, Anthony J; Giersig, Michael

    2014-10-21

    Anisotropic deformation of polystyrene particles in an oxygenated (O2/Ar) plasma is observed for radio frequency (rf) plasma and inductively coupled plasma (ICP). A facile model based on a ratio of completely isotropic and completely anisotropic etching is presented to describe the anisotropy of the etching process and is implemented to determine the height of the spheroid-shaped polystyrene particles. In our systems, we find the plasma etching to be 54% isotropic in the rf plasma and 79% isotropic in the ICP. With this model, the maximum material deposition thickness for nanofabrication with plasma-etched nanosphere lithography or colloid lithography can be predicted. Moreover, the etching of polystyrene particles in an oxygenated plasma is investigated versus the etching time, gas flow, gas composition, temperature, substrate material, and particle size. The results of this study allow precise shape tuning during the fabrication of nanostructured surfaces with size-dependent properties for bionic, medical, and photonic applications.

  18. DiSC-OPAL: A Simulation Framework For Real-time Assessment of Distribution Grids

    DEFF Research Database (Denmark)

    Kemal, Mohammed Seifu; Pedersen, Rasmus; Iov, Florin

    2017-01-01

    Smart grid functionalities require developing, testing and verification of complex systems in a realistic environment that captures the three main domains: Control, ICT, and Electrical Grid. Real-time simulations that can support hardware in the loop methods have a pivotal role for modeling of su...

  19. NDSC Lidar Intercomparisons and Validation: OPAL and MLO3 Campaigns in 1995

    Science.gov (United States)

    McDermid, Stuart; McGee, Thomas J.; Stuart, Daan P. J.

    1996-01-01

    The Network for the Detection of Stratospheric Change (NDSC) has developed and adopted a Validation Policy in order to ensure that the results submitted and stored in its archives are of a known, high quality. As a part of this validation policy, blind instrument intercomparisons are considered an essential element in the certification of NDSC instruments and a specific format for these campaigns has been recommended by the NDSC-Steering Committee.

  20. Nanoassembly of Polydisperse Photonic Crystals based on Binary and Ternary Polymer Opal Alloys

    CERN Document Server

    Zhao, Qibin; Schafer, Christian; Spahn, Peter; Gallei, Markus; Herrmann, Lars; Petukhov, Andrei; Baumberg, Jeremy J

    2016-01-01

    Ordered binary and ternary photonic crystals, composed of different sized polymer-composite spheres with diameter ratios up to 120%, are generated using bending induced oscillatory shearing (BIOS). This viscoelastic system creates polydisperse equilibrium structures, producing mixed opaline colored films with greatly reduced requirements for particle monodispersity, and very different sphere size ratios, compared to other methods of nano-assembly.

  1. Decay-mode independent searches for new scalar bosons with the OPAL detector at LEP

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Allison, John; Amaral, P.; Anagnostou, G.; Anderson, K.J.; Arcelli, S.; Asai, S.; Axen, D.; Azuelos, G.; Bailey, I.; Barberio, E.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Boeriu, O.; Bock, P.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Brigliadori, L.; Brown, Robert M.; Buesser, K.; Burckhart, H.J.; Cammin, J.; Campana, S.; Carnegie, R.K.; Caron, B.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Cohen, I.; Csilling, A.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Elfgren, E.; Etzion, E.; Fabbri, F.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Gagnon, P.; Gary, John William; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harder, K.; Harel, A.; Harin-Dirac, M.; Hauschild, M.; Hauschildt, J.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hill, J.C.; Hoffman, Kara Dion; Homer, R.J.; Horvath, D.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Klute, M.; Kluth, S.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kormos, Laura L.; Kowalewski, Robert V.; Kramer, T.; Kress, T.; Krieger, P.; von Krogh, J.; Krop, D.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, J.; Macpherson, A.; Mader, W.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Masetti, G.; Mashimo, T.; Mattig, Peter; McDonald, W.J.; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Menges, W.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Moed, S.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Rick, H.; Roney, J.M.; Rosati, S.; Rozen, Y.; Runge, K.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharoe-Hansen, P.; Schieck, J.; Schoerner-Sadenius, Thomas; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Spano, F.; Stahl, A.; Stephens, K.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Taylor, R.J.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trefzger, T.; Tricoli, A.; Trigger, I.; Trocsnyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vachon, B.; Vollmer, C.F.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.; Zivkovic, Lidija

    2003-01-01

    This paper describes topological searches for neutral scalar bosons S0 produced in association with a Z0 boson via the Bjorken process e+e- -> S0Z0 at centre-of-mass energies of 91 GeV and 183-209 GeV. These searches are based on studies of the recoil mass spectrum of Z0 -> e+e- and mu+mu- events on a search for S0Z0 with Z0 -> nunu bar and S0 -> e+e- or photons. They cover the decays of the S0 into an arbitrary combination of hadrons, leptons, photons and invisible particles as well as the possibility that it might be stable. No indication for a signal is found in the data and upper limits on the cross section of the Bjorken process are calculated. Cross-section limits are given in terms of a scale factor k with respect to the Standrad Model cross section for the Higgs-strahlung process e+e- -> H0smZ0. These results can be interpreted in general scenarios independently of the decay modes of the S0. The examples considered here are the production of a single new scalar particle with a decay width smaller than...

  2. Localized surface plasmon-influenced fluorescence decay in dye-doped metallo-dielectric opals

    Energy Technology Data Exchange (ETDEWEB)

    Rout, Dipak [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Vijaya, R. [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Centre for Lasers and Photonics, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2016-01-14

    Well-ordered opaline photonic crystals are grown by inward growing self-assembly method from Rhodamine B dye-doped polystyrene colloids. Subsequent to self-assembly, the crystals are infiltrated with gold nanoparticles of 40 nm diameter. Measurements of the stopband features and photoluminescence intensity from these crystals are supplemented by fluorescence decay time analysis. The fluorescence decay times from the dye-doped photonic crystals before and after the infiltration are dramatically different from each other. A lowered fluorescence decay time was observed for the case of gold infiltrated crystal along with an enhanced emission intensity. Double-exponential decay nature of the fluorescence from the dye-doped crystal gets converted into single-exponential decay upon the infiltration of gold nanoparticles due to the resonant radiative process resulting from the overlap of the surface plasmon resonance with the emission spectrum. The influence of localized surface plasmon due to gold nanoparticles on the increase in emission intensity and decrease in decay time of the emitters is established.

  3. The new neutron radiography/tomography/imaging station DINGO at OPAL

    Energy Technology Data Exchange (ETDEWEB)

    Garbe, U., E-mail: ulf.garbe@ansto.gov.au [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia); Randall, T.; Hughes, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234 (Australia)

    2011-09-21

    A new neutron imaging instrument will be built to support the area of neutron imaging research (neutron radiography/tomography) at ANSTO. The instrument will be designed for an international user community and for routine quality control for defence, industrial, mining, space and aircraft applications. It will also be a useful tool for assessing oil and water flow in sedimentary rock reservoirs (like the North West Shelf), assessing water damage in aircraft components, and the study of hydrogen distribution and cracking in steel. The instrument is planned to be completed by the end of June 2013 and is currently in the design stage. The usable neutron flux is mainly determined by the neutron source, but it also depends on the instrument position and the resolution. The designated instrument position for DINGO is the beam port HB-2 in the reactor hall. The estimated flux for an L/D of approximately 250 at HB-2 is calculated by Mcstas simulation in a range of 4.75x10{sup 7} n/cm{sup 2} s, which is in the same range of other facilities like ANSTARES (FRM II; Schillinger et al., 2004 ) or BT2 (NIST; Hussey et al., 2005 ). A special feature of DINGO is the in-pile collimator place in front of the main shutter at HB-2. The collimator offers two pinholes with a possible L/D of 250 and 1000. A secondary collimator will separate the two beams and block one. The whole instrument will operate in two different positions, one for high resolution and the other for high speed.

  4. Phase space optimisation of the USANS instrument Kookaburra at the ANSTO OPAL reactor

    Science.gov (United States)

    Freund, A. K.; Rehm, C.

    2011-04-01

    An optimisation of the USANS instrument Kookaburra has been conducted determining the most efficient type of premonochromator crystal and scattering geometry. The approach has been based on representations in phase space combining direct and reciprocal space diagrams. Results are presented for several scenarios involving flat and curved, perfect and mosaic crystals, horizontal and vertical scattering planes. The highest peak current density of 1.7×105 cm-2 s-1 is provided for a wavelength of 4.43 Å by a doubly curved pyrolytic graphite premonochromator diffracting in a horizontal plane and producing a beam size of about 50 cm2 at the sample position. The smallest background is achieved for a wavelength of 2.56 Å and a vertical scattering plane using a bent perfect premonochromator crystal and optionally a collimator to decrease the divergence of the beam exiting the cold neutron guide. For this wavelength a peak current density of 6.6×104 cm-2 s-1 is collected into a sample area of 10 cm2. The bent perfect crystal design is of particular advantage for small samples.

  5. The new neutron radiography/tomography/imaging station DINGO at OPAL

    Science.gov (United States)

    Garbe, U.; Randall, T.; Hughes, C.

    2011-09-01

    A new neutron imaging instrument will be built to support the area of neutron imaging research (neutron radiography/tomography) at ANSTO. The instrument will be designed for an international user community and for routine quality control for defence, industrial, mining, space and aircraft applications. It will also be a useful tool for assessing oil and water flow in sedimentary rock reservoirs (like the North West Shelf), assessing water damage in aircraft components, and the study of hydrogen distribution and cracking in steel. The instrument is planned to be completed by the end of June 2013 and is currently in the design stage. The usable neutron flux is mainly determined by the neutron source, but it also depends on the instrument position and the resolution. The designated instrument position for DINGO is the beam port HB-2 in the reactor hall. The estimated flux for an L/ D of approximately 250 at HB-2 is calculated by Mcstas simulation in a range of 4.75×10 7 n/cm 2 s, which is in the same range of other facilities like ANSTARES (FRM II; Schillinger et al., 2004 [1]) or BT2 (NIST; Hussey et al., 2005 [2]). A special feature of DINGO is the in-pile collimator place in front of the main shutter at HB-2. The collimator offers two pinholes with a possible L/ D of 250 and 1000. A secondary collimator will separate the two beams and block one. The whole instrument will operate in two different positions, one for high resolution and the other for high speed.

  6. Phase space optimisation of the USANS instrument Kookaburra at the ANSTO OPAL reactor

    Energy Technology Data Exchange (ETDEWEB)

    Freund, A.K., E-mail: kafreund@free.f [Via Cordis, 92, rue Abbe de l' Epee, F-33000 Bordeaux (France); Institut Max von Laue - Paul Langevin, B.P. 156, F-38042 Grenoble, Cedex (France); Rehm, C. [ANSTO, Bragg Institute, Locked Bag 2001, Kirrawee DC, NSW 2232 (Australia)

    2011-04-01

    An optimisation of the USANS instrument Kookaburra has been conducted determining the most efficient type of premonochromator crystal and scattering geometry. The approach has been based on representations in phase space combining direct and reciprocal space diagrams. Results are presented for several scenarios involving flat and curved, perfect and mosaic crystals, horizontal and vertical scattering planes. The highest peak current density of 1.7x10{sup 5} cm{sup -2} s{sup -1} is provided for a wavelength of 4.43 A by a doubly curved pyrolytic graphite premonochromator diffracting in a horizontal plane and producing a beam size of about 50 cm{sup 2} at the sample position. The smallest background is achieved for a wavelength of 2.56 A and a vertical scattering plane using a bent perfect premonochromator crystal and optionally a collimator to decrease the divergence of the beam exiting the cold neutron guide. For this wavelength a peak current density of 6.6x10{sup 4} cm{sup -2} s{sup -1} is collected into a sample area of 10 cm{sup 2}. The bent perfect crystal design is of particular advantage for small samples.

  7. Semitransparent Metallic Photonic Crystals: Variety of Plasmons in Inverted Opal Nano-Meshes

    Science.gov (United States)

    Zakhidov, Anvar; Baughman, Ray; Khayrullin, Ilyas; Wiley, John; Eradat, Nayer; Efros, Alex; Vardeny, Valy

    2001-03-01

    We have recently fabricated three-dimensional nano-structures by self-assembling sub-micron particles into 3-D porous superlattices, and templating them with practically any material, both electrically conductive and insulating, including carbon [1], thermoelectric semiconductors [2], polymers [3], and magnets [4]. Being photonic crystals (PCs), our superlattices possess new, unconventional properties, such as the tunable intra-gap lasing [5], anomalous coherent backscattering [6], and structural solvatochromism. Here we describe synthesis and physical properties of another class of photonic crystals, called plasmon or metallic PC. Their metallo-dielectric structure has a metallic (or plasmon) photonic band gap (PBG) in IR spectral range, and therefore shows unusual optical properties. Of particular interest is the increased transparency and reflectivity spectrum, different from that of usual bulk metal. We demonstrate that by changing the topology from a network (continuos mesh) to a cermet (discontinuous web) one can achieve tunability of reflectivity peak in IR via modulation of plasmon spectrum and the metallicity PBG [7]. The theoretical model, which takes into account 1-D plasmon, surface plasmon and effectively changed 3-D plasmon (due to low filling factor), explains the observed peaks in reflectivity, and increase of the transparency. Such semitransparent metallic nano-meshes can be used for example as electrodes for LEDs and lasers. 1. A.A. Zakhidov, et al, Science, 282 (1998) 897. 2. R.H. Baughman, et al . Proc. ICT'98 (1998) 288. 3. A.A. Zakhidov, et al., Nanostructured Materials, 12 (1999) 1089. 4. T.-B,Xu, et al, J. Appl. Phys, 88 (2000) 405. 5. L.Xu, et al, Chem. Comm., (2000) 997. 6. M.N. Shkunov, et al. Synth.Met (in press), 7. AA. Zakhidov, et al., Synthetic Metals (in press).

  8. Oxygen isotope mass balance of atmospheric nitrate at Dome C, East Antarctica, during the OPALE campaign

    Science.gov (United States)

    Savarino, Joël; Vicars, William C.; Legrand, Michel; Preunkert, Suzanne; Jourdain, Bruno; Frey, Markus M.; Kukui, Alexandre; Caillon, Nicolas; Gil Roca, Jaime

    2016-03-01

    Variations in the stable oxygen isotope composition of atmospheric nitrate act as novel tools for studying oxidative processes taking place in the troposphere. They provide both qualitative and quantitative constraints on the pathways determining the fate of atmospheric nitrogen oxides (NO + NO2 = NOx). The unique and distinctive 17O excess (Δ17O = δ17O - 0.52 × δ18O) of ozone, which is transferred to NOx via oxidation, is a particularly useful isotopic fingerprint in studies of NOx transformations. Constraining the propagation of 17O excess within the NOx cycle is critical in polar areas, where there exists the possibility of extending atmospheric investigations to the glacial-interglacial timescale using deep ice core records of nitrate. Here we present measurements of the comprehensive isotopic composition of atmospheric nitrate collected at Dome C (East Antarctic Plateau) during the austral summer of 2011/2012. Nitrate isotope analysis has been here combined for the first time with key precursors involved in nitrate production (NOx, O3, OH, HO2, RO2, etc.) and direct observations of the transferrable Δ17O of surface ozone, which was measured at Dome C throughout 2012 using our recently developed analytical approach. Assuming that nitrate is mainly produced in Antarctica in summer through the OH + NO2 pathway and using concurrent measurements of OH and NO2, we calculated a Δ17O signature for nitrate on the order of (21-22 ± 3) ‰. These values are lower than the measured values that ranged between 27 and 31 ‰. This discrepancy between expected and observed Δ17O(NO3-) values suggests the existence of an unknown process that contributes significantly to the atmospheric nitrate budget over this East Antarctic region. However, systematic errors or false isotopic balance transfer functions are not totally excluded.

  9. Oxygen isotope mass balance of atmospheric nitrate at Dome C, East Antarctica, during the OPALE campaign

    Directory of Open Access Journals (Sweden)

    J. Savarino

    2015-09-01

    Full Text Available Variations in the stable oxygen isotope composition of atmospheric nitrate act as novel tools for studying oxidative processes taking place in the troposphere. They provide both qualitative and quantitative constraints on the pathways determining the fate of atmospheric nitrogen oxides (NO + NO2 = NOx. The unique and distinctive 17O-excess (Δ17O = δ17O − 0.52 × δ18O of ozone, which is transferred to NOx via oxidation, is a particularly useful isotopic fingerprint in studies of NOx transformations. Constraining the propagation of 17O-excess within the NOx cycle is critical in polar areas where there exists the possibility of extending atmospheric investigations to the glacial/interglacial time scale using deep ice core records of nitrate. Here we present measurements of the comprehensive isotopic composition of atmospheric nitrate collected at Dome C (East Antarctic plateau during the austral summer of 2011/12. Nitrate isotope analysis has been here combined for the first time with key precursors involved in nitrate production (NOx, O3, OH, HO2, RO2, etc. and direct observations of the transferrable Δ17O of surface ozone, which was measured at Dome C throughout 2012 using our recently developed analytical approach. Assuming that nitrate is mainly produced in Antarctica in summer through the OH + NO2 pathway and using concurrent measurements of OH and NO2, we calculated a Δ17O signature for nitrate in the order of (21–22 ± 3 ‰. These values are lower than the measured values that ranged between 27 and 31 ‰. This discrepancy between expected and observed Δ17O(NO3− values suggests the existence of an unknown process that contributes significantly to the atmospheric nitrate budget over this east Antarctic region.

  10. Inverse opal structured α-Fe2O3 on graphene thin films: enhanced photo-assisted water splitting

    Science.gov (United States)

    Zhang, Kan; Shi, Xinjian; Kim, Jung Kyu; Lee, Jae Sung; Park, Jong Hyeok

    2013-02-01

    A graphene interlayer was successfully inserted into inverse opaline hematite (α-Fe2O3) photoanodes for solar water splitting using the template assisted electrodeposition method. Finding the optimal thermal annealing temperature is crucial for the successful attainment of the inverse opaline hematite nanostructure on a graphene thin film. This is because an appropriate temperature is required to convert pre-deposited Fe0 into hematite with optimum crystalline structure and to simultaneously remove the soft polystyrene template without thermal degradation of the graphene film on a transparent conductive substrate. Different from the conventional strategies based on graphene-semiconductor systems, this novel mechanism has been proposed whereby the graphene interlayer can act as both an electron transfer layer and an electrolyte blocking barrier, by which it not only reduces the charge recombination at the substrate-electrolyte interface but also helps electron transportation from α-Fe2O3 to the substrate of the photoanode. Therefore, both photocurrent density and incident photon-to-current efficiency (IPCE) have been remarkably improved, which are several times higher than those of the pure inverse opaline hematite photoanode.A graphene interlayer was successfully inserted into inverse opaline hematite (α-Fe2O3) photoanodes for solar water splitting using the template assisted electrodeposition method. Finding the optimal thermal annealing temperature is crucial for the successful attainment of the inverse opaline hematite nanostructure on a graphene thin film. This is because an appropriate temperature is required to convert pre-deposited Fe0 into hematite with optimum crystalline structure and to simultaneously remove the soft polystyrene template without thermal degradation of the graphene film on a transparent conductive substrate. Different from the conventional strategies based on graphene-semiconductor systems, this novel mechanism has been proposed whereby the graphene interlayer can act as both an electron transfer layer and an electrolyte blocking barrier, by which it not only reduces the charge recombination at the substrate-electrolyte interface but also helps electron transportation from α-Fe2O3 to the substrate of the photoanode. Therefore, both photocurrent density and incident photon-to-current efficiency (IPCE) have been remarkably improved, which are several times higher than those of the pure inverse opaline hematite photoanode. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr33036a

  11. Evidence for opal phytolith preservation in the Langebaanweg ‘E’ Quarry Varswater Formation and its potential for palaeohabitat reconstruction

    Directory of Open Access Journals (Sweden)

    P. Haarhof

    2010-01-01

    Full Text Available At the end of the Miocene epoch, C4 grasslands began to expand at the expense of tree-, shrub- and forb-dominated C3 ecosystems. While C4 grasses were spreading throughout most regions of the world, C3 grasses may have been spreading along South Africa’s southwest coast. Stable isotope analyses of hypsodont fossil ungulates from ‘E’ Quarry, a well-known Late Miocene/Early Pliocene fossil locality near the town of Langebaanweg, suggest that the local environment might have included a substantial C3 grass component. Besides this indirect evidence, little is known about the evolution, nature and importance of grass in the ‘E’ Quarry biome. As a preliminary step towards addressing these questions, we initiated a trial investigation to assess whether sediments at the site are conducive to the preservation of phytoliths, an important tool in the reconstruction of palaeohabitats. Results indicate that fossil phytoliths are sufficiently well preserved to allow a comprehensive analysis of the ‘E’ Quarry phytolith assemblage.

  12. Modelling relationships between lichen bioindicators, air quality and climate on a national scale: results from the UK OPAL air survey.

    Science.gov (United States)

    Seed, Lindsay; Wolseley, Pat; Gosling, Laura; Davies, Linda; Power, Sally A

    2013-11-01

    Air pollution has many negative effects on the natural environment, from changes in plant growth patterns to loss of ecosystem function. This study uses citizen science to investigate national-scale patterns in the distribution and abundance of selected lichen species on tree trunks and branches, and to relate these to air pollution and climate. Volunteers collected data for nine lichen indicators on 19,334 deciduous trees. Submitted data provided information on species-level patterns, and were used to derive composite lichen indices. Multiple linear regression and ANCOVA were used to model the relationships between lichen response variables on Quercus spp. and pollution, climate and location. The study demonstrated significant relationships between patterns in indicator lichens and levels of N- and S-containing pollutants on trunks and twigs. The derived lichen indices show great potential as a tool to provide information on local, site-specific levels of air quality. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Optimisation and fabrication of a composite pyrolytic graphite monochromator for the Pelican instrument at the ANSTO OPAL reactor

    Science.gov (United States)

    Freund, A. K.; Yu, D. H.

    2011-04-01

    The triple monochromator for the TOF neutron spectrometer Pelican at ANSTO has been fully optimised in terms of overall performance, including the determination of the thickness of the pyrolytic graphite crystals. A total of 24 composite crystals were designed and fabricated. The calculated optimum thickness of 1.3 mm and the length of 15 cm of the monochromator crystals, that are not available commercially, were obtained by cleaving and soldering with indium. An extensive characterisation of the crystals using X-ray and neutron diffraction was conducted before and after the cleaving and bonding processes. The results proved that no damage was introduced during fabrication and showed that the design goals were fully met. The measured peak reflectivity and rocking curve widths were indeed in an excellent agreement with theory. In addition to the superior efficiency of the triple monochromator achieved by this novel approach, the amount of the crystal material required could be reduced by 1/3.

  14. Opponent actor learning (OpAL): modeling interactive effects of striatal dopamine on reinforcement learning and choice incentive.

    Science.gov (United States)

    Collins, Anne G E; Frank, Michael J

    2014-07-01

    The striatal dopaminergic system has been implicated in reinforcement learning (RL), motor performance, and incentive motivation. Various computational models have been proposed to account for each of these effects individually, but a formal analysis of their interactions is lacking. Here we present a novel algorithmic model expanding the classical actor-critic architecture to include fundamental interactive properties of neural circuit models, incorporating both incentive and learning effects into a single theoretical framework. The standard actor is replaced by a dual opponent actor system representing distinct striatal populations, which come to differentially specialize in discriminating positive and negative action values. Dopamine modulates the degree to which each actor component contributes to both learning and choice discriminations. In contrast to standard frameworks, this model simultaneously captures documented effects of dopamine on both learning and choice incentive-and their interactions-across a variety of studies, including probabilistic RL, effort-based choice, and motor skill learning.

  15. Preparation of Si inverse Opal structure embedded in Si flute by PECVD%PECVD制备嵌埋在硅槽中的硅反Opal结构

    Institute of Scientific and Technical Information of China (English)

    韩喻; 谢凯; 李宇杰; 许静

    2006-01-01

    摸索了利用PECVD方法制备嵌埋于硅槽中Si反Opal结构的工艺条件,探索性研究了射频功率、气体流量、反应室压力、沉积时间和Opal基底状态对填充效果的影响.结果显示射频功率越小,流量越低,反应室压力越大,则反应速率越低,Opal结构内外填充越均匀.同时,在[SiHm]自由基扩散通道不被堵塞的前提下,沉积时间越长,Opal结构排列越规整,则整体填充越致密,越有利于反Opal结构的形成.

  16. Risque environnemental et action collective : l’exemple de la gestion du risque d’érosion à Wissant (Côte d’Opale)

    National Research Council Canada - National Science Library

    Herbert, Vincent; Maillefert, Muriel; Petit, Olivier; Zuindeau, Bertrand

    2009-01-01

    Cet article vise à mettre en question les rapports qui s’établissent entre les risques environnementaux, leur perception par les acteurs et les mesures qui sont effectivement prises face à ces risques...

  17. APPLICATION OF THE THERMAL CONDUCTIVITY CRITERION IN THE DESIGN OF FOAM-CERAMIC CONCRETES BASED ON THE OPAL-CRYSTOBALITE ROCK

    Directory of Open Access Journals (Sweden)

    Korolev Evgeniy Valerevich

    2012-10-01

    Full Text Available Design method of the foam-ceramic concrete with the pre-set value of thermal conductivity is proposed. Computed dependencies between the thermal conductivity, strength and generalized structural criterion - porosity - are presented. As a result of the research, it was identified that local input materials are ecological and easy to extract, and that they may be used as the mineral basis for the manufacturing of effective foam-glass ceramic materials that demonstrate their porous structure, similar to the one of the foam-ceramic concrete. The employment of the proposed approach to the design of the composition of foam-glass ceramic materials may substantially improve the most important properties of this material, namely, it may reduce the sorption capacity and improve the strength, if compared with the benchmark composition.

  18. Uso de opalas biogênicas na identificação de sedimentos lacustres e marinhos Biogenic opals in the identification of lacustrine and marine sediments

    OpenAIRE

    João Luiz Lani; Larry Schwandes; Sérvulo Batista de Rezende; José Antonio Lani; Eufran Ferreira do Amaral; Alexson de Mello Cunha; Liovando Marciano da Costa

    2007-01-01

    Procurou-se utilizar opalas biogênicas, também conhecidas como espículas ou "pó-de-mico", como identificadoras de sedimentos lacustres ou marinhos. Para isso, analisaram-se camadas e horizontes de um Gleissolo Tiomórfico Húmico na região do rio Riacho, Aracruz, ES. Cada amostra de solo foi submetida a tratamentos específicos para o isolamento das espículas; posteriormente, elas foram identificadas em microscópico eletrônico de varredura. Verificou-se a presença de espículas de origem tanto la...

  19. Measurement of heavy quark forward-backward asymmetries and the B mixing parameter using Z decays recorded with the OPAL detector at LEP

    CERN Document Server

    Krämer, Thomas; Büßer, F W

    2004-01-01

    This thesis deals with the measuremen t of the b and c quark forw ard-bac kward asymmetries of hadronic Z deca ys recorded with the OP AL exp erimen t at the electron positron collider LEP . After an overview over the di eren t kinds of hea vy avour forw ard-bac kward asymmetry measuremen ts made within the OP AL col- lab oration, one of the metho ds is describ ed in full detail. This metho d is based on the semileptonic b and c quark deca ys in order to identify primary b b and c c events. Tw o neural net works are used to separate the b b and c c events from eac h other and from the bac kground. The rst neural net work is trained to identify b->l-, the second to iden tify c ! ` + deca ys. A maxim um likeliho od t is used to extract the b and c quark forw ard-bac kward asymmetries A b FB and A c FB at three cen tre-of-mass energies p s and the average B mixing parameter from a sample with at least one iden ti ed electron or muon in the nal state. (not complete)

  20. 新疆蛋白土超细加工及改性土应用研究%Study on Application of Modified Superfine Opal in Xinjiang

    Institute of Scientific and Technical Information of China (English)

    任元成; 侯向群; 轩峰; 朱明胜

    2005-01-01

    以新疆蛋白土为原料,进行了超细加工并经偶联剂改性处理的超细蛋白土(蛋白土硅质沥表改性剂)改性基质沥青及混合料试验研究.结果表明:改性超细蛋白土作为沥青改性剂用于沥青改性,改性沥青混合料路用性能良好,同时改性沥青的生产成本亦低.

  1. 用蛋白土制备硅酸钠工艺研究%Research on Preparing Sodium Silicate by Opal

    Institute of Scientific and Technical Information of China (English)

    王钰; 陈俊涛; 郑水林; 黄鹏

    2007-01-01

    采用水热碱溶法研究了用蛋白土制取硅酸钠的工艺条件和主要影响因素.正交试验结果表明:反应时间、NaOH用量以及体系的液固比,对蛋白土SiO2的浸出率和硅酸钠溶液模数的加权值的影响都非常显著.各因素对试验结果的影响显著性顺序为:氢氧化钠用量>液固比>反应时间.其中氢氧化钠的用量对实验结果的影响,远远大于其它影响因素.最佳制备工艺条件为:反应时间75min,NaOH用量与蛋白土用量之比为0.325,液固比为3.0.

  2. Study on Preparation Sodium Metasilicate from Opal%用蛋白土制备偏硅酸钠的方法研究

    Institute of Scientific and Technical Information of China (English)

    尹桂珍; 黄敏

    2003-01-01

    @@ 1前言 自从合成洗涤剂问世以来,人们一直在不断地选择适宜的洗涤助剂.由于三聚磷酸钠Na5P3O10(STPP)具有良好的界面活性、乳化分散性、缓冲性和胶溶能力,目前仍然被认为是最理想的洗涤助剂.但是,磷酸盐含量过高会造成河、湖水污染.

  3. Use of Fly Ash in the Mitigation of Alkali-Silica Reaction in Concrete

    Science.gov (United States)

    2010-11-12

    crystallinity of the silica and its solubility. Common reactive minerals susceptible to ASR include strained quartz, cristobalite , opal, obsidian, chert, and...residues, whereas alkali-silica reactive components include opal, cristobalite , tridymite, siliceous and some intermediate volcanic glass, chert

  4. Theoretical study on anderson localization of opal photonic crystal in the infrared%类Opal光子晶体红外区安德森定域化理论研究

    Institute of Scientific and Technical Information of China (English)

    田贵才; 姜成果; 贾继奎

    2008-01-01

    本文根据Mie散射理论和低浓度近似下,对在中红外区高折射率半导体材料AlP等做为散射体的类Opal光子晶体的安德森定域化进行了理论研究,发现在浓度为10%,折射率比值大于3.8,无吸收状态下,此类晶体将出现两个定域化区.同时为此类晶体的定域化研究提供了一个比较理想的处理方法.

  5. Synthesis and Characterization of Tunable Opal Photonic Crystals with Isotropic Structure%带隙可调各向同性蛋白石光子晶体的制备与研究

    Institute of Scientific and Technical Information of China (English)

    于晓伟; 郭金宝; 魏杰

    2012-01-01

    In this study, polystyrene microspheres assembling photonic crystals were fabricated by spin coating. Features of photonic crystals were studied, and the influence of different parameters on photonic band gap with a certain size microspheres was analyzed. The results showed that; photonic crystals fabricated by spin coating presented isotropic characteristics, and the photonic band gap of photonic crystal could be controlled by changing parameters. The reflection band of photonic crystal depended on mass fraction of microspheres, and the intensity depended on layers of spin coating. Consequently, we can control the photonic band gap via changing mass fraction of microspheres and layers of spin coating according to the requirement during designing the photonic crystal.%用旋涂法将聚苯乙烯微球组装成光子晶体,研究了此光子晶体的特点,并分析了在单一微球粒径下旋涂参数对光子带隙的影响.结果表明:旋涂法制备的光子晶体具有各向同性特点,其光子带隙由旋涂参数决定.光子晶体的反射波段取决于乳液中微球的质量分数,而反射强度取决于旋涂层数.因此,在设计光子晶体时,可以根据需要,通过微球的质量分数和旋涂层数的改变实现对光子带隙的控制.

  6. 蛋白土/纳米二氧化钛复合材料的制备与应用研究%Study on Preparation and Application of Nano-TiO2/opal Composite Material

    Institute of Scientific and Technical Information of China (English)

    文明; 郑水林; 刘月; 熊余; 王兴华

    2008-01-01

    用酸处理方法对煅烧后的蛋白土进行提纯后采用湿式研磨法在其表面包覆纳米TiO2,通过单因素法确定最佳复合条件.实验结果表明,纳米TiO2/蛋白土复合粉体材料的最佳制备工艺条件为:研磨时间15min,分散剂用量为0.3%,TiO2加入量10%,液固比4:1.湿式研磨法制备的蛋白土/纳米二氧化钛复合材料8h内对甲醛的去除率达到71.2%.

  7. Application of Nenjiang Opal Shale in Polymer Materials%嫩江蛋白石轻质页岩及在高分子材料中的应用

    Institute of Scientific and Technical Information of China (English)

    李青山; 陈洁; 高洁; 王庆瑞; 齐凤林; 扬宝臣; 周可富

    2003-01-01

    本文用X-射线衍射仪、扫描电镜、红外光谱、差热分析方法分析认定了嫩江蛋白石的结构和形态,探讨了蛋白石超细微粉在高分子材料中的应用.实验结果表明:聚合物/蛋白石复合材料对ABS树脂增韧效果明显.

  8. Geochemistry and diagenesis of Miocene lacustrine siliceous sedimentary and pyroclastic rocks, Mytilinii basin, Samos Island, Greece

    Science.gov (United States)

    Stamatakis, M.G.; Hein, J.R.; Magganas, A.C.

    1989-01-01

    A Late Miocene non-marine stratigraphic sequence composed of limestone, opal-CT-bearing limestone, porcelanite, marlstone, diatomaceous marlstone, dolomite, and tuffite crops out on eastern Samos Island. This lacustrine sequence is subdivided into the Hora Beds and the underlying Pythagorion Formation. The Hora Beds is overlain by the clastic Mytilinii series which contains Turolian (Late Miocene) mammalian fossils. The lacustrine sequence contains volcanic glass and the silica polymorphs opal-A, opal-CT, and quartz. Volcanic glass predominantly occurs in tuffaceous rocks from the lower and upper parts of the lacustrine sequence. Opal-A (diatom frustules) is confined to layers in the upper part of the Hora Beds. Beds rich in opal-CT underlie those containing opal-A. The occurrence of opal-CT is extensive, encompassing the lower Hora Beds and the sedimentary rocks and tuffs of the Pythagorion Formation. A transition zone between the opal-A and opal-CT zones is identified by X-ray diffraction patterns that are intermediate between those of opal-CT and opal-A, perhaps due to a mixture of the two polymorphs. Diagenesis was not advanced enough for opal-CT to transform to quartz or for volcanic glass to transform to opal-C. Based on geochemical and mineralogical data, we suggest that the rate of diagenetic transformation of opal-A to opal-CT was mainly controlled by the chemistry of pore fluids. Pore fluids were characterized by high salinity, moderately high alkalinity, and high magnesium ion activity. These pore fluid characteristics are indicated by the presence of evaporitic salts (halite, sylvite, niter), high boron content in biogenic silica, and by dolomite in both the opal-A and opal-CT-bearing beds. The absence of authigenic K-feldspar, borosilicates, and zeolites also support these pore fluid characteristics. Additional factors that influenced the rate of silica diagenesis were host rock lithology and the relatively high heat flow in the Aegean region from

  9. Silica photonic crystals with quasi-full band gap in the visible region prepared in ethanol

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hui; WANG Xidong; ZHAO Xiaofeng; LI Wenchao; TANG Qing

    2003-01-01

    Monodisperse silica spheres of 252 nm with a standard deviation of 5.7% are prepared by Stber method. By comparison of both of media, ethanol instead of water is used to assemble opal, and the artificial opal has been prepared by the sedimentation in ethanol of silica spheres. The structure of the opal prepared has been examined and discussed. The results show that the artificial opal has a structure similar to the face-centered cubic (fcc) type packed system with silica spheres. Transmission measurements of the artificial opal have been conducted, which shows that the artificial opal is quasi-full band gap silica photonic crystals in the visible region.

  10. Diagenesis of silica-rich mounded chalk, the Coniacian Arnager Limestone, Denmark

    DEFF Research Database (Denmark)

    Buus Madsen, Heine; Stemmerik, Lars; Surlyk, Finn

    2010-01-01

    , clinoptilolite, feldspars, calcite, dolomite, and barite. Opal-CT and clinoptilolite are the most common and constitute 16-53% and 2-9%, respectively. The content of insoluble minerals varies laterally bothwithinthemounds and inplanar beds, and the opal-CT content varies by up to 10% vertically. Themounds...... precipitation of opal-CT. The opal-CT formed at temperatures around 17°C, the precipitation lowered the silica activity and the Si/Al ratio of the pore water, resulting in precipitation of clinoptilolite, feldspar and smectite. Calcite formed synchronouslywith the latest clinoptilolite.Minoramounts of quartz...

  11. Stimulated Globular Scattering of Laser Radiation in Photonic Crystals: Temperature Dependences

    CERN Document Server

    Gorelik, V S; Tcherniega, N V; Vodchits, A I

    2007-01-01

    Stimulated globular scattering (SGS) characteristics (frequency shifts, threshold, conversion efficiency) have been studied in photonic crystals (synthetic opal matrices and opal nanocomposites) at different temperatures. Results have been compared with stimulated Raman scattering investigations in calcite single crystals. In both cases temperature lowering from +20 C to -196 C resulted in the stimulated scattering energy increase and its redistribution to the higher order components.

  12. Lidar Architecture for Harsh Environment Applications

    Science.gov (United States)

    Church, Philip

    2016-06-01

    An overview is provided of the obscurantpenetrating OPAL lidar sensor developed for harsh environments, including poor visibility conditions. The underlying technology, hardware and software architecture of the sensor are presented along with some examples of its software modules' applications. The paper also discusses the performance of the OPAL in the presence of various types of obscurants.

  13. Lidar Architecture for Harsh Environment Applications

    Directory of Open Access Journals (Sweden)

    Church Philip

    2016-01-01

    Full Text Available An overview is provided of the obscurantpenetrating OPAL lidar sensor developed for harsh environments, including poor visibility conditions. The underlying technology, hardware and software architecture of the sensor are presented along with some examples of its software modules’ applications. The paper also discusses the performance of the OPAL in the presence of various types of obscurants.

  14. 球状晶体中的拉曼散射和布拉格衍射%Raman Scattering and Bragg Diffraction in Globular Crystals

    Institute of Scientific and Technical Information of China (English)

    V.I.; Burkov; V.S.; Gorelik; P.P.; Sverbil; S.N.; Ivicheva; L.I.; Zlobina; A.V.; Chervyakov

    2005-01-01

    @@ The results of optical properties investigations for some types of globular crystals, including artifical opals and amorphous substances, constructed from the globular nanoclusters are represented. The spectra of light reflection from the surface of received opals have investigated at different incident angle(under mirror-reflection geometry): 0, 20, 30, 45 and 60 degree.

  15. lead glass brick

    CERN Multimedia

    As well as accelerators to boost particles up to high energy, physicists need detectors to see what happens when those particles collide. This lead glass block is part of a CERN detector called OPAL. OPAL uses some 12 000 blocks of glass like this to measure particle energies.

  16. Silicon Nanotips and Related Nano-Systems Involving Fluid and Carrier Transport and Their Micro-Devices for Power and Sensing Applications

    Science.gov (United States)

    2011-05-10

    Schematic diagram of the novel catalyst CuO-ZnO inverse opals fabricated on the inner surface of the microchannel reactor . Fig. 2 (a) SEM image of the...well-defined inverse opal nanostructure (Figure 1) on the inner surface of microchannels , via direct synthesis, for microreformer applications. The 3

  17. Diagenesis of the Sedimentary Rocks Enclosing Coaly Layers in Gavatha Area,Lesvos Island,Based on Silica Polymorph‘s Transformations

    Institute of Scientific and Technical Information of China (English)

    A.KELEPERTSIS

    1996-01-01

    A Tertiary non-marine stratigraphic sequence composed of carbonates(limestone),siliceous carbonates,coaly layers overlain by pyroclastic rocks and lavas,outcrops in the Gavatha area of northwestern Lesvos Island.Pure earbonates eonsist almost completely of calcite,the siliceous carbonate sediments of quartz,opal-CT and calcite,the shales of quartz,opal CT, K-feldspar,smecite-illite and ealcite,and the coaly layers of organic matter,quartz,opal-CT,feldspars and pyrite,Geochemical data indicate that smectite-illite,feldspars and associated elements(La,Zr,Y,Ba,Ce)are the products of alteration of volcanic rocks in a subtropical area A combination of sources in suggested for the formation of silica polymorphs:(a) biogenic or non-biogenic silica(opal-A) that was originally present in the form of diatiom frustules of in the form of inorganically prccipitated silica;(b)transformation o opall-A to opal-CT and quartz opal-C from alteration of volcanic glass of intercalated tuffites and overlying volcanics;and(c)opal-CT deposited primarily from hydrothermal solutions.

  18. Diagenetic Variations between Upper Cretaceous Outcrop and Deeply Buried Reservoir Chalks of the North Sea Area

    DEFF Research Database (Denmark)

    Hjuler, Morten Leth; Fabricius, Ida Lykke

    2007-01-01

    -particle connections and less altered particle shapes. The non-carbonate mineralogy of outcrop chalks is dominated by quartz, occasionally opal-CT and clinoptilolite, and the clay mineral smectite. In offshore chalks quartz still dominates, opal-CT has recrystallized into submicron-size quartz crystals and smectite...

  19. Optical study of Sb-S-I glass photonic crystals

    Science.gov (United States)

    Starczewska, Anna; Kępińska, Mirosława; Nowak, Marian; Szperlich, Piotr

    2015-12-01

    This work is focused on optical investigations of Sb-S-I glass photonic crystals based on three-dimensional opal template with a closed-packed face centered cubic (fcc) lattice prepared from monodisperse silicon (SiO2) spheres by gravity sedimentation. Three types of photonic structures have been examined: SiO2-opals, opals filled with Sb-S-I glass (direct opals) and Sb-S-I inverted opals obtained after removing SiO2 templates. Optical properties have been investigated by reflectance spectroscopy for wavelengths from 250 nm to 1100 nm. These measurements exhibit Bragg's peaks connected with photonic band gap that is tunable in position and width by varying the diameter of spheres and medium filling the opal. Values of the real parts of refractive index of the Sb-S-I in the fabricated inverted opals nmed[λ ∈ (850-950) nm] = 2.42 ± 0.08 and nmed[λ ∈ (675-750) nm] = 2.39 ± 0.11 have been determined.

  20. Novel photoluminescence-enhancing substrates for image formation of biological objects

    CERN Document Server

    Dovbeshko, G I; Boyko, V V; Gorchev, V F; Karakhin, S O; Gridina, N Ya; Gorelik, V S; Moiseenko, V N

    2012-01-01

    The use of photonic crystals, which were fabricated on the basis of synthetic opals, as substrates for the luminescence microscopy of biological objects has been shown. The spatial distributions of the photoluminescence by DNA clusters excited by 365-nm ultraviolet irradiation on opal surfaces and rough gold substrates have been studied. With the use of blood cells as an example, a possibility for the visualization of biological objects in the case where the nanostructure elements of synthetic opals are applied as labels and image amplifiers has been demonstrated.

  1. Fano resonance between Mie and Bragg scattering in photonic crystals.

    Science.gov (United States)

    Rybin, M V; Khanikaev, A B; Inoue, M; Samusev, K B; Steel, M J; Yushin, G; Limonov, M F

    2009-07-10

    We report the observation of a Fano resonance between continuum Mie scattering and a narrow Bragg band in synthetic opal photonic crystals. The resonance leads to a transmission spectrum exhibiting a Bragg dip with an asymmetric profile, which can be tunably reversed to a Bragg rise. The Fano asymmetry parameter is linked with the dielectric contrast between the permittivity of the filler and the specific value determined by the opal matrix. The existence of the Fano resonance is directly related to disorder due to nonuniformity of a-SiO2 opal spheres. The theoretical "quasi-3D" model produces results in excellent agreement with the experimental data.

  2. Effect of Photonic Structure on Optical Properties of YVO4:Eu3+ Phosphor

    Science.gov (United States)

    Thakur, Shashi; Dhiman, Naresh; Sharma, Amit; Gathania, Arvind K.

    2016-11-01

    Polymethyl methacrylate (PMMA) photonic crystal has been prepared on quartz substrate by the self-assembly vertical deposition technique. YVO4:Eu3+ inverse opal was obtained by annealing PMMA photonic crystal infiltrated with YVO4:Eu3+ nanophosphors at 500°C for 3 h. Scanning electron microscopy confirmed the development of the photonic and inverse opal structures. Photoluminescence study showed that the luminescence characteristics depended on the position of the photonic stop band. It was observed that the photoluminescence intensity of YVO4:Eu3+ inverse opal was enhanced near the photonic stop bandgap edge as compared with the intensity of a YVO4:Eu3+ nanophosphor powder sample.

  3. A randomised controlled trial investigating the effect of n-3 long-chain polyunsaturated fatty acid supplementation on cognitive and retinal function in cognitively healthy older people: the Older People And n-3 Long-chain polyunsaturated fatty acids (OPAL study protocol [ISRCTN72331636

    Directory of Open Access Journals (Sweden)

    Letley Louise

    2006-08-01

    Full Text Available Abstract The number of individuals with age-related cognitive impairment is rising dramatically in the UK and globally. There is considerable interest in the general hypothesis that improving the diet of older people may slow the progression of cognitive decline. To date, there has been little attention given to the possible protective role of n-3 long-chain polyunsaturated fatty acids (n-3 LCPs most commonly found in oily fish, in age-related loss of cognitive function. The main research hypothesis of this study is that an increased dietary intake of n-3 LCPs will have a positive effect on cognitive performance in older people in the UK. To test this hypothesis, a double-blind randomised placebo-controlled trial will be carried out among adults aged 70–79 years in which the intervention arm will receive daily capsules containing n-3 LCP (0.5 g/day docosahexaenoic acid and 0.2 g/day eicosapentaenoic acid while the placebo arm will receive daily capsules containing olive oil. The main outcome variable assessed at 24 months will be cognitive performance and a second major outcome variable will be retinal function. Retinal function tests are included as the retina is a specifically differentiated neural tissue and therefore represents an accessible window into the functioning of the brain. The overall purpose of this public-health research is to help define a simple and effective dietary intervention aimed at maintaining cognitive and retinal function in later life. This will be the first trial of its kind aiming to slow the decline of cognitive and retinal function in older people by increasing daily dietary intake of n-3 LCPs. The link between cognitive ability, visual function and quality of life among older people suggests that this novel line of research may have considerable public health importance.

  4. 以胶体晶为模板溶胶凝胶法制备二氧化钛掺铈反蛋白石结构%Fabrication of TiO2 Doped Cerium Inverse Opal Structure by Sol-gel Method Using Colloid Crystal as Template

    Institute of Scientific and Technical Information of China (English)

    金谊; 朱以华; 杨晓玲; 干路平

    2007-01-01

    以乳液聚合法得到的单分散性聚苯乙烯(PS)胶体粒子为模板,采用恒温恒湿垂直沉积法构建蛋白石结构的光子晶体,并用布拉格方程对不同粒径形成的蛋白石结构所产生的禁带位置进行了研究.以该肢体晶为模板溶胶凝胶法制备二氧化钛(TiO2)掺杂铈(Ce)反蛋白石结构,并利用XRD和XPS对其结晶状态和元素价态进行分析.

  5. P-Ink and Elast-Ink from lab to market

    National Research Council Canada - National Science Library

    Ozin, Geoffrey A; Arsenault, Andre C

    2008-01-01

    ... to a commercializable technology. Two of these nanotechnology platforms, termed P-Ink and Elast-Ink, are both founded on active color tuning of opals, a capability that provides electrical and mechanical access to materials with any...

  6. Integration of self-assembled three-dimensional photonic crystals onto structured silicon wafers.

    Science.gov (United States)

    Ye, Jianhui; Zentel, Rudolf; Arpiainen, Sanna; Ahopelto, Jouni; Jonsson, Fredrik; Romanov, Sergei G; Sotomayor Torres, Clivia M

    2006-08-15

    We report on the fabrication of high-quality opaline photonic crystals from large silica spheres (diameter of 890 nm), self-assembled in hydrophilic trenches of silicon wafers by using a novel technique coined a combination of "lifting and stirring". The achievements reported here comprise a spatial selectivity of opal crystallization without special treatment of the wafer surface, a filling of the trenches up to the top, leading to a spatially uniform film thickness, particularly an absence of cracks within the size of the trenches, and finally a good 3D order of the opal lattice even in trenches with a complex confined geometry, verified using optical measurements. The opal lattice was found to match the pattern precisely in width as well as depth, providing an important step toward applications of opals in integrated optics.

  7. 2002 Institute of Physics awards

    CERN Multimedia

    2001-01-01

    The IOP Rutherford Medal and prize was awarded to P Dornan, W Venus and D Plane for their major contributions to the detectors and leadership of the LEP, ALEPH, OPAL and DELPHI experiments (4 paragraphs).

  8. Pore-filling Three-dimensionally Ordered Macroporous Polyimide Composite Proton Conducting Membranes

    Institute of Scientific and Technical Information of China (English)

    DAI Xin; GENG Lei; LIU Dan; L(U) Chang-li; YANG Bai

    2011-01-01

    The silica opal templates were prepared from three silica colloids of different diameters of 230 nm,500nm and 1.5 μm by a filtration route.The large-scale stable opal template membranes after sintering the deposited SiO2 opal template can be successfully obtained by optimizing the pH value and NaCl concentration in silica colloidal solutions.The three-dimensionally ordered macroporous(3DOM) polyimide membranes without crack were fabricated by reproducing the structure of silica opal template.We prepared the pore-filling composite proton exchange membranes by filling the 3DOM structure with proton conducting organosilane sol.The result indicates that the composite membranes exhibit higher water uptake than pure filling organosilane gel.The proton conductivity increased with the increasing of pore cell in composite membranes.

  9. Inheritance of resistance to cotton blue disease Herança da resistência do algodoeiro à doença-azul

    Directory of Open Access Journals (Sweden)

    Osmério Pupim Junior

    2008-05-01

    Full Text Available The objective of this work was to determine the inheritance of cotton blue disease resistance by cotton plants. Populations derived from the CD 401 and Delta Opal resistant varieties were evaluated, through a greenhouse test with artificial inoculation by viruliferous aphids. Cotton blue disease resistance is conditioned by one dominant gene, both in CD 401 and Delta Opal varieties.O objetivo deste trabalho foi determinar a herança da resistência do algodoeiro à doença-azul. Populações derivadas das variedades resistentes CD 401 e Delta Opal foram avaliadas em casa de vegetação, por meio da inoculação de pulgões virulíferos. A resistência à doença-azul do algodoeiro é condicionada por um gene dominante, tanto em 'DC 401' quanto em 'Delta Opal'.

  10. 36 CFR 13.1 - Definitions.

    Science.gov (United States)

    2010-07-01

    ... means a silica or igneous mineral including, but not limited to: (1) Geodes; (2) Petrified wood; and (3) Jade, agate, opal, garnet, or other mineral that when cut and polished is customarily used as...

  11. Cemented Volcanic Soils, Martian Spectra and Implications for the Martian Climate

    Science.gov (United States)

    Bishop, J. L.; Schiffman, P.; Drief, A.; Southard, R. J.

    2004-03-01

    Cemented volcanic crusts are studied to learn about their composition, formation processes, and implications for climate interactions with the surface on Mars. Such carbonate, sulfate and opal crusts may be present in cemented soil units on Mars.

  12. Optical Payload for Lasercomm Science Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Optical Payload for Lasercomm Science (OPALS), which is part of the JPL Phaeton early career employee hands-on training program, aims to demonstrate optical...

  13. Thermophysical Properties of Matter - The TPRC Data Series. Volume 8. Thermal Radiative Properties - Nonmetallic Solids

    Science.gov (United States)

    1972-01-01

    Iron oxldes- kaolin -aagneslum oxides- manganese oxldes-marble-nlckel oxldes-obsldlan-opal-opal glass-plexlglas- mylar—polyethylene-pyrocerams—quarts...magnesium oxide, magnesium carbon- ate, high-purity barium sulphate, sodium chloride, flowers of sulphur , and some good white paints [I, 50, 76]. For...S. T.. "Application of Sulphur Coatings to Integrating Spheres." Appl. Opt.. 4(4). 377, 1965. Dunn. S. T.. "Flux Averaging Devices for the

  14. Lithogenic fluxes in the Bay of Bengal measured by sediment traps

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaswamy, V.; VijayKumar, B.; Parthiban, G.; Ittekkot, V.; Nair, R.R.

    % for opal, Si concentrations were multiplied by 2.4 to calculate biogenic opal content. Lithogenic fluxes were estimated by weighing the material remaining after removal of carbonate (30% v/v dilute acetic acid), organic matter (with 30% hydrogen peroxide... solution) and biogenic silica (with 1 M sodium carbonate). Dilute acetic acid and hydrogen peroxide does not attack clay minerals significantly. Leaching of the lithogenic fraction by 1 M sodium carbonate is generally less than 1% of the total lithogenic...

  15. Development of an optical parallel logic device and a half-adder circuit for digital optical processing

    Science.gov (United States)

    Athale, R. A.; Lee, S. H.

    1978-01-01

    The paper describes the fabrication and operation of an optical parallel logic (OPAL) device which performs Boolean algebraic operations on binary images. Several logic operations on two input binary images were demonstrated using an 8 x 8 device with a CdS photoconductor and a twisted nematic liquid crystal. Two such OPAL devices can be interconnected to form a half-adder circuit which is one of the essential components of a CPU in a digital signal processor.

  16. Development of an optical parallel logic device and a half-adder circuit for digital optical processing

    Science.gov (United States)

    Athale, R. A.; Lee, S. H.

    1978-01-01

    The paper describes the fabrication and operation of an optical parallel logic (OPAL) device which performs Boolean algebraic operations on binary images. Several logic operations on two input binary images were demonstrated using an 8 x 8 device with a CdS photoconductor and a twisted nematic liquid crystal. Two such OPAL devices can be interconnected to form a half-adder circuit which is one of the essential components of a CPU in a digital signal processor.

  17. Residual Stress Development in Explosive-Bonded Bi-Metal Composite Materials

    Science.gov (United States)

    2014-03-01

    responsible for the residual stress diffractometer at the OPAL research reactor, since joining ANSTO in 2006. His expertise covers neutron diffraction...neutron research facilities JINR (pulsed reactor IBR-2), GKSS (neutron facility FRG-1), NIST (research reactor NBSR) and ANSTO (OPAL research reactor...at ANSTO , researching high temperature fatigue behaviour and modelling of ferritic pressure vessel steel, for which he was awarded the degree at

  18. Reactivity of Quartz at Normal Temperatures.

    Science.gov (United States)

    1984-07-01

    Scanlon, Chief, Concrete Technology Division, and Bryant Mather, Chief, SL. The report was prepared by A. D. Buck. Others ac- tively engaged in the work...included J. P. Burkes, G. S. Wong, Jay E. Rhoderick, Ron Reinhold, J. F. Jones, and T. G. Ray. Commander and Director of the WES during preparation and...forms of common opal and presumably precious opal. (2) Vitreous silica. c. Minerals or varieties. (1) Tridymite. (2) Cristobalite . 5-. . . .: .~i p (3

  19. Kinetics of silica-phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, C.J.

    1993-07-01

    In addition to the stable silica polymorph quartz, several metastable silica phases are present in Yucca Mountain. The conversion of these phases to quartz is accompanied by volume reduction and a decrease in the aqueous silica activity, which may destabilize clinoptilolite and mordenite. The primary reaction sequence for the silica phases is from opal or glass to disordered opal-CT, followed by ordering of the opal-CT and finally by the crystallization of quartz. The ordering of opal-CT takes place in the solid state, whereas the conversion of opal-CT takes place through dissolution-reprecipitation involving the aqueous phase. It is proposed that the rate of conversion of opal-CT to quartz is controlled by diffusion of defects out of a disordered surface layer formed on the crystallizing quartz. The reaction rates are observed to be dependent on temperature, pressure, degree of supersaturation, and pH. Rate equations selected from the literature appear to be consistent with observations at Yucca Mountain.

  20. Kinetics of silica-phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, C.J.

    1993-07-01

    In addition to the stable silica polymorph quartz, several metastable silica phases are present in Yucca Mountain. The conversion of these phases to quartz is accompanied by volume reduction and a decrease in the aqueous silica activity, which may destabilize clinoptilolite and mordenite. The primary reaction sequence for the silica phases is from opal or glass to disordered opal-CT, followed by ordering of the opal-CT and finally by the crystallization of quartz. The ordering of opal-CT takes place in the solid state, whereas the conversion of opal-CT takes place through dissolution-reprecipitation involving the aqueous phase. It is proposed that the rate of conversion of opal-CT to quartz is controlled by diffusion of defects out of a disordered surface layer formed on the crystallizing quartz. The reaction rates are observed to be dependent on temperature, pressure, degree of supersaturation, and pH. Rate equations selected from the literature appear to be consistent with observations at Yucca Mountain.

  1. The effect of heating on mineral composition and grain size distribution of flux calcined porcelanites from the Gafsa-Metlaoui basin, southwestern Tunisia

    Science.gov (United States)

    Saidi, Raja; Tlili, Ali; Jamoussi, Fakher

    2016-12-01

    The porcelanite rock of Ypresian phosphatic series of the Gafsa-Metlaoui basin (south-western Tunisia), is composed mainly of opal CT, and presents a variable percentage of carbonates and fibrous clays. This rock is treated with flux calcination at different temperatures in order to prepare a specific filter aid for cleaning melting sulfur which can be used for the production of sulfuric acid. This work presents the effect of heating on the mineralogy and grain size distribution of carbonate-rich porcelanite (Tm1) and clay-rich porcelanite (Gh) compared to flux calcined silica-rich porcelanite (CHM3) and diatomaceous filtration aids. The porcelanite samples used in this work come from three localities of the Gafsa-Metlaoui basin: Kef El Ghis (Gh), Tamarza (Tm1) and Mides (CHM3). Flux calcination at 1000 °C provokes a mineralogical transformation on carbonate-rich porcelanite samples. The opal CT transforms to opal C and becomes neater and more stable. The Thermal treatment of porcelanite (Tm1) incites also the apparition of new peaks of wollastonite. However, the structural change of opal CT to opal C by heat treatment is blocked for flux calcination of clay-rich porcelanite. The opal CT of fluxing clay-rich porcelanite becomes more ordered without significant change to opal C. The difference between fluxing carbonate-rich porcelanite (Tm1) and fluxing clay-rich porcelanite (Gh) appears also with granulometric distribution histogram of the tow heated samples. All raw samples have unimodal granulometric distribution (1-100 μm). After calcination with alkaline flux at 1000 °C fluxing carbonate-rich porcelanite displays bimodal granulometric distribution and a new mode appears systematically, between 0.1 μm and 1 μm. This occurs for fluxing silica-riche porcelanite and diatomaceous filtration aids as well and corresponds to the opal C formed after heat treatment. Whereas fluxing clay-rich porcelanite present trimodal granulometric distribution and a third mode

  2. MODIFIED OPAL: A NOVEL STABILIZER FOR HYDROGEN PEROXIDE BLEACHING OF PULPS

    Institute of Scientific and Technical Information of China (English)

    XuerenQian; XianhuiAn; WenboLiu; GangYu; ZhanqianSong

    2004-01-01

    The possibility of modified opal as the stabilizer ofhydrogen peroxide bleaching was investigated. Theresults showed that the modified opal in place ofsodium silicate as the stabilizer of hydrogen peroxidebleaching is feasible. At the same dosage, above 3%ISO can be increased for both wheat straw pulp anddeinked pulp. The stabilizing ability of the modifiedopal to hydrogen peroxide bleaching of pulp isimproved markedly. It is favorable for bleaching toincrease temperature and time within a permissiveextent. The suitable process conditions are I0% ofpulp consistency, 3% of hydrogen peroxide, 1.5% ofsodium hydroxide, 3% of the modified opal, 70~"and 60 min when the modified opal is used as thestabilizer of hydrogen peroxide bleaching. At theseconditions, the brightness gain can reach about 16%ISO for wheat straw pulp. In addition, it is favorablefor bleaching to add a little magnesium sulfate whenthe modified opal is used as the stabilizer ofhydrogen peroxide bleaching, the brightness of pulpcan increase 1%ISO if0.05% of magnesium sulfate isadded. The cost analysis indicated that the modifiedopal is superior to sodium silicate as the stabilizer ofhydrogen peroxide bleaching in economical aspectand has further the potential of market development.

  3. Study of the structure of 3D-ordered macroporous GaN-ZnS:Mn nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Kurdyukov, D. A., E-mail: kurd@gvg.ioffe.ru; Shishkin, I. I.; Grudinkin, S. A.; Sitnikova, A. A.; Zamoryanskaya, M. V.; Golubev, V. G. [Russian Academy of Sciences, Ioffe Physical-Technical Institute (Russian Federation)

    2015-05-15

    A film-type 3D-ordered macroporous GaN-ZnS:Mn nanocomposite with the structure of an inverted opal is fabricated. Structural studies of the nanocomposite are performed, and it is shown that GaN and ZnS:Mn introduced into the pores of the silica opal are nanocrystallites misoriented with respect to each other. It is shown that the nanocomposite is a structurally perfect 3D photonic crystal. The efficiency of using a buffer of GaN crystallites to preclude interaction between the surface of the spherical a-SiO{sub 2} particles forming the opal matrix and chemically active substances introduced into the pores is demonstrated.

  4. MESO—STRUCTURED POLYMERIC HYDROGELS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhongYang; Jian-huaRong; DanLi

    2003-01-01

    Meso-structured(opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods:post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers.A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color,which is important in designing tunable photonic crystals.Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed.The catalytic effect of acid groups in the templates was emphasized for a preferential formation of TiO2 in the region containing acid groups,which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  5. MESO-STRUCTURED POLYMERIC HYDROGELS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang; Jian-hua Rong; Dan Li

    2003-01-01

    Meso-structured (opal and inverse opal) polymeric hydrogels of varied morphology and composition were prepared by using two methods: post-modification of the template-synthesized structured polymers and templatepolymerization of functional monomers. A polyacrylic acid based inverse opal hydrogel was chosen to demonstrate its fast pH response by changing color, which is important in designing tunable photonic crystals. Template effects of the hydrogels on controlling structure of the template-synthesized inorganic materials were discussed. The catalytic effect of acid groups inthe templates was emphasized for a preferential formation of TiO2 in the region containing acid groups, which allowed duplicating inorganic colloidal crystals from colloidal crystal hydrogels (or macroporous products from macroporous hydrogels) via one step duplication.

  6. Petrography and Diagenesis of Palaeocene -Eocene Sandstones in the Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari

    and sorting of heavy mineral grains in these sediments is controlled primarily by grain size, shape and density.   Heavy minerals may be selectively concentrated during transport and deposition because of their high density.  Selective concentration of heavy minerals is thought to take place through...... cemented in two major phases - an early opal/microquartz phase and a late stage massive cementation by macroquartz.  This study explores the potential sources of SiO2 in the shale, and the timing of their active phases.   The main diagenetic phases recorded are smectite, heulandite, opal...... components results in successive stages of silica-release.  In shallow samples the alteration of volcanic ash has already been completed.  Released silica was partly consumed for the precipitation of smectite and heulandite.   In addition, a major part of the biogenic silica has been transformed into opal...

  7. 2D and 3D photonic crystal materials for photocatalysis and electrochemical energy storage and conversion.

    Science.gov (United States)

    Collins, Gillian; Armstrong, Eileen; McNulty, David; O'Hanlon, Sally; Geaney, Hugh; O'Dwyer, Colm

    2016-01-01

    This perspective reviews recent advances in inverse opal structures, how they have been developed, studied and applied as catalysts, catalyst support materials, as electrode materials for batteries, water splitting applications, solar-to-fuel conversion and electrochromics, and finally as photonic photocatalysts and photoelectrocatalysts. Throughout, we detail some of the salient optical characteristics that underpin recent results and form the basis for light-matter interactions that span electrochemical energy conversion systems as well as photocatalytic systems. Strategies for using 2D as well as 3D structures, ordered macroporous materials such as inverse opals are summarized and recent work on plasmonic-photonic coupling in metal nanoparticle-infiltrated wide band gap inverse opals for enhanced photoelectrochemistry are provided.

  8. Siliceous alterations of the Montana Senalo lavas, Timanfaya eruption (1730-1736) (Lanzarote, Canary Islands); Las alteraciones siliceas de las lavas de Montana Senalo, eruption de Timanfaya (1730-1736) (Lanzarote, Islas Canarias)

    Energy Technology Data Exchange (ETDEWEB)

    Carmona, J.; Romero, C.; Doniz, J.; Garcia, A.

    2009-07-01

    The presence of hydrothermal alterations within the lavas of Timanfaya eruption (1730-1736), with high proportions of quartz and opal, suggests the effective circulation of hot fluids. The source of these fluids would be located under the island, where silica would be dissolved from sandstones and radiolarites, moving this way towards the surface as Si(OH){sub 4} colloids. Study of opal indicates the presence of A-initial CT and C phases in the collected samples, which, considering the time needed for producing this phase transformations in the diagenetic evolution of opal (10,000-50,000 years), suggests an accelerating process, probably related with either the presence of fluid circulation or weathering processes. Such circumstances are necessary for explaining the presence of such components affecting 300 years old lavas. (Author) 36 refs.

  9. IPOPv2 online service for the generation of opacity tables

    Science.gov (United States)

    Delahaye, Franck; Zwölf, Carlo Maria; Zeippen, Claude J.; Mendoza, Claudio

    2016-03-01

    In the framework of the present phase - IPOPv2 - of the international Opacity Project (OP), a new web service has been implemented based on the latest release of the OP opacities. The user may construct online opacity tables to be conveniently included in stellar evolution codes in the format most commonly adopted by stellar physicists, namely the OPAL format. This facility encourages the use and comparison of both the OPAL and OP data sets in applications. The present service allows for the calculation of multi-element mixtures containing the 17 species (H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni) considered by the OP, and underpins the latest release of OP opacities. This new service provides tables of Rosseland mean opacites using OP atomic data. We provide an alternative to the OPAL opacity services allowing direct comparison as well as study of the effect of uncertainties in stellar modeling due to mean opacities.

  10. Face-Centered-Cubic Nanostructured Polymer Foams

    Science.gov (United States)

    Cui, C.; Baughman, R. H.; Liu, L. M.; Zakhidov, A. A.; Khayrullin, I. I.

    1998-03-01

    Beautifully iridescent polymer foams having Fm-3m cubic symmetry and periodicities on the scale of the wavelength of light have been synthesized by the templating of porous synthetic opals. These fabrication processes involve the filling of porous SiO2 opals (with typical cubic lattice parameters of 250 nm) with either polymers or polymer precursors, polymerization of the precursors if necessary, and removal of the fcc array of SiO2 balls to provide an all-polymer structure. The structures of these foams are similar to periodic minimal surfaces, although the Gaussian curvature can have both positive and negative values. Depending upon whether the internal surfaces of the opal are polymer filled or polymer coated, the polymer replica has either one or two sets of independent channels. We fill these channels with semiconductors, metals, or superconductors to provide electronic and optical materials with novel properties dependent on the nanoscale periodicity.

  11. IPOPv2 online service for the generation of opacity tables

    CERN Document Server

    Delahaye, F; Zeippen, C; Mendoza, C

    2015-01-01

    In the framework of the present phase -- IPOPv2 -- of the international Opacity Project (OP), a new web service has been implemented based on the latest release of the OP opacities. The user may construct online opacity tables to be conveniently included in stellar evolution codes in the format most commonly adopted by stellar physicists, namely the OPAL format. This facility encourages the use and comparison of both the OPAL and OP data sets in applications. The present service allows for the calculation of multi-element mixtures containing the 17 species (H, He, C, N, O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Cr, Mn, Fe and Ni) considered by the OP, and underpins the latest release of OP opacities. This new service provides tables of Rosseland mean opacites using OP atomic data. We provide an alternative to the OPAL opacity services allowing direct comparison as well as study of the effect of uncertainties in stellar modeling due to mean opacities.

  12. Late Pliocene to early Pleistocene (2.4-1.25 Ma) paleoproductivity changes in the Bering Sea: IODP expedition 323 Hole U1343E

    Science.gov (United States)

    Kim, Sunghan; Khim, Boo-Keun; Takahashi, Kozo

    2016-03-01

    Late Pliocene to early Pleistocene paleoproductivity changes in the Bering Sea were reconstructed using geochemical concentrations and mass accumulation rates (MARs) of CaCO3, biogenic opal, and total organic carbon (TOC), and sedimentary nitrogen isotope ratios (δ15N) at IODP Expedition 323 Hole U1343E, drilled in the northern slope area (1956 m deep) of the Bering Sea. CaCO3 concentration is generally low, but prominent CaCO3 peaks occur intermittently due to subseafloor authigenic carbonate formation rather than biogenic accumulation, regardless of glacial-interglacial variations. Biogenic opal concentrations reflect orbital-scale glacial-interglacial variations. However, TOC concentration did not show clear glacial-interglacial variation, probably due to poor preservation. The sedimentary δ15N values vary synchronously with biogenic opal concentration on orbital timescales. The co-varying pattern of opal productivity and δ15N values at Hole U1343E is a result of nutrient utilization controlled by diatom productivity in the Bering slope area where Fe is not a limiting factor. Biogenic opal and TOC MARs showed a temporal shift at around 1.9 Ma from a high productivity period under nutrient-enriched conditions to a low productivity period under relatively nutrient-depleted conditions. High diatom productivity with low δ15N values before 1.9 Ma is associated with abundant nutrient supply by upwelling in relation to strong surface current system. This productivity decrease at about 1.9 Ma was also found in the southern Bering Sea (Site U1341) and may be related to global opal reorganization.

  13. Effect of irradiation times on the polymerization depth of contemporary fissure sealants with different opacities

    Directory of Open Access Journals (Sweden)

    Boniek Castillo Dutra Borges

    2011-04-01

    Full Text Available The aim of this study was to evaluate the depth of curing of 10 contemporary blue light-activated dental flowable materials at several opacities, influenced by different irradiation times using FT-IR spectroscopy. Fifty-five specimens (n = 5 with a 5-mm diameter and 1-mm thickness of translucent (Opallis Flow T, yellowed (Master Flow A2; Opallis Flow A2; Natural Flow A2; Fluroshield Yellowed, and opaque materials (Master Flow OA2; Natural Flow O; Opallis Flow OA3.5; Opallis Flow OP; Fluroshield White were obtained at six curing times (10s, 20s, 30s, 40s, 50s, and 60s using a high-intensity LED (Coltolux, Coltène/Whaledent. The degree of conversion (DC (% was obtained using the Nexus 470 FTIR Spectrometer (Nicolet Instruments, USA. The FTIR-ATR spectra for uncured and cured samples were analyzed using a ZnSe crystal. The top and bottom surfaces of the cured specimens were analyzed to obtain the depth of curing. Two-way ANOVA was used to analyze the data. The highest curing depth was obtained by Natural Flow OA2, while the lowest was shown by Master Flow OA2. The shortest curing time generated similar depths of cure in comparison with the most extensive for Opallis Flow A2 and Fluroshield Yellowed. Therefore, depth of curing, influenced by the irradiation time, was dependent on the materials. Using the Natural Flow OA2 opaque sealant and the 10-s curing time for Opallis Flow A2 and Fluroshield Yellowed may represent alternative approaches to sealing tooth fissures.

  14. Oviposição de Alabama argillacea Hübner (Lepidoptera: Noctuidae) em cultivares de algodoeiro e parasitismo natural de ovos por Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) na região de Chapadão do Sul, MS

    OpenAIRE

    Silva, Elias Almeida [UNESP

    2009-01-01

    Alabama argillacea (Hübner) é praga chave do algodoeiro no Brasil. Com o objetivo de estudar a intensidade de oviposição de A. argillacea e o parasitismo de seus ovos por Trichogramma pretiosum Riley, nos estágios fenológicos de sete cultivares, instalou-se o experimento na Fazenda Savana na região de Chapadão do Sul, MS, no ano agrícola 2006/07. As cultivares FMT 701, FMX 966, Acala 90, NuOPAL, Delta Penta, CD 409 e DeltaOPAL, foram semeadas em 20/12/2006, no Delineamento de Blocos Casualiza...

  15. Three dimensional confinement of vapor in nanostructures for sub-Doppler optical resolution

    CERN Document Server

    Ballin, Philippe; Maurin, Isabelle; Laliotis, Athanasios; Bloch, Daniel

    2013-01-01

    We confine a Cs thermal vapor in the interstitial regions of a glass opal. We perform linear reflection spectroscopy on a cell whose window is covered with a thin film (10 or 20 layers) of ~ 1000 nm (or 400 nm) diameter glass spheres, we observe sub-Doppler structures in the optical spectrum for a large range of oblique incidences. This original feature associated with the inner (3-dimension) confinement of the vapor in the interstitial regions of the opal, evokes a Dicke narrowing. We finally consider possible micron-size references for optical frequency clocks based on weak, hard to saturate, molecular lines.

  16. Measurement of the Low-x Behaviour of the Photon Structure Function $F2-\\gamma$

    CERN Document Server

    Abbiendi, G.; Ainsley, C.; Akesson, P.F.; Alexander, G.; Allison, John; Anderson, K.J.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Bailey, I.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Biebel, O.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Boeriu, O.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Cammin, J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Dallison, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanti, M.; Feld, L.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Glenzinski, D.; Goldberg, J.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hauke, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Hensel, C.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karapetian, G.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klein, K.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I.; Layter, J.G.; Leins, A.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; Lillich, J.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Marchant, T.E.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oh, A.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poli, B.; Polok, J.; Pooth, O.; Przybycien, M.; Quadt, A.; Rembser, C.; Rick, H.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sarkisyan, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schmitt, S.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Tarem, S.; Taylor, R.J.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trefzger, T.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Vannerem, P.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Waller, D.; Ward, C.P.; Ward, D.R.; Ward, J.J.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    2000-01-01

    The photon structure function F2-gamma(x,Q**2) has been measured using data taken by the OPAL detector at centre-of-mass energies of 91Gev, 183Gev and 189Gev, in Q**2 ranges of 1.5 to 30.0 GeV**2 (LEP1), and 7.0 to 30.0 GeV**2 (LEP2), probing lower values of x than ever before. Since previous OPAL analyses, new Monte Carlo models and new methods, such as multi-variable unfolding, have been introduced, reducing significantly the model dependent systematic errors in the measurement.

  17. Liquid-crystal photonic-band-gap materials the tunable electromagnetic vacuum

    CERN Document Server

    Busch, K

    1999-01-01

    We demonstrate that when an optically birefringent nematic liquid crystal is infiltrated into the void regions of an inverse opal, photonic-band-gap (PBG) material, the resulting composite material exhibits a completely tunable PBG. $9 In particular, the three- dimensional PBG can be completely opened or closed by applying an electric field which rotates the axis of the nematic molecules relative to the inverse opal backbone. Tunable light localization effects may $9 be realized by controlling the orientational disorder in the nematic. (28 refs).

  18. Electrochemical synthesis of macroporous zinc oxide layers by employing hydrogen peroxide as oxygen precursor

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France); Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Bartlett, Philip; Abdelsalam, Mamdouh [School of Chemistry, University of Southampton (United Kingdom); Gomez, Humberto [Instituto de Quimica, Pontificia Universidad Catolica de Valparaiso, Valparaiso (Chile); Lincot, Daniel [Laboratoire d' Electrochimie et Chimie Analytique (UMR CNRS 7575), Ecole Nationale Superieure de Chimie de Paris (ENSCP) (France)

    2008-10-15

    Two- and three-dimensional ordered porous zinc oxide (ZnO) films were prepared by electrodeposition on Indium Tin Oxide coated glass, using two- and three-dimensional poly(styrene) opal templates. The oxide was formed by electrochemical reduction of hydrogen peroxide in aqueous zinc perchlorate solution. Scanning electron microscopy measurements showed well ordered inverse opal structures for macroporous ZnO. At high hydrogen peroxide concentration, dense inner conformal filling was achieved for 2D and 3D structures. The formation of nanocrystalline ZnO was checked by X-ray diffraction. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Determination of the LEP Beam Energy using Radiative Fermion-pair Events, 2004

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, G; Allison, J; Amaral, P; Anagnostou, G; Anderson, K J; Asai, S; Axen, D A; Bailey, I; Barberio, E; Barillari, T; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Boeriu, O; Bock, P; Boutemeur, M; Braibant, S; Brown, R M; Burckhart, H J; Campana, S; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Ciocca, C; Csilling, A; Cuffiani, M; Dado, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Etzion, E; Fabbri, Franco Luigi; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Gagnon, P; Gary, J W; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harel, A; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, R J; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Horváth, D; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanzaki, J; Karlen, Dean A; Kawagoe, K; Kawamoto, T; Keeler, R K; Kellogg, R G; Kennedy, B W; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kramer, T; Krieger, P; Von Krogh, J; Kühl, T; Kupper, M; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, A; Ludwig, J; Mader, W; Marcellini, S; Martin, A J; Masetti, G; Mashimo, T; Mättig, P; McKenna, J A; McPherson, R A; Meijers, F; Menges, W; Merritt, F S; Mes, H; Meyer, N; Michelini, A; Mihara, S; Mikenberg, G; Miller, D J; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Nanjo, H; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Pilcher, J E; Pinfold, J L; Plane, D E; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Roney, J M; Rossi, A M; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vollmer, C F; Vannerem, P; Vertesi, R; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2004-01-01

    We present a determination of the LEP beam energy using "radiative return" fermion-pair events recorded at centre-of-mass energies from 183 GeV to 209 GeV. We find no evidence of a disagreement between the OPAL data and the LEP Energy Workings Group's standard calibration. Including the energy- averaged 11 MeV uncertainty in the standard determination, the beam energy we obtain from the OPAL data is higher than that obtained from the LEP calibration by 0+-34(stat.)+-27(syst.)MeV

  20. SimulatorToFMU v0.1

    Energy Technology Data Exchange (ETDEWEB)

    2017-07-26

    SimulatorToFMU is a software package written in Python which allows users to export a memoryless Python-driven simulation program or script as a Functional Mock-up Unit (FMU) for model exchange or co-simulation.In CyDER (Cyber Physical Co-simulation Platform for Distributed Energy Resources in Smart Grids), SimulatorToFMU will allow exporting OPAL-RT as an FMU. This will enable OPAL-RT to be linked to CYMDIST and GridDyn FMUs through a standardized open source interface.

  1. B and D Spectroscopy at LEP

    CERN Document Server

    Muheim, F

    1999-01-01

    Results from the four LEP experiments ALEPH, DELPHI, L3, and OPAL on the spectroscopy of B and charmed mesons are presented. The predictions of Heavy Quark Effective Theory (HQET) for the masses and the widths of excited L=1 B mesons are supported by a new measurement from L3. A few B_c candidate eve nts have masses consistent with the recent CDF observation and the predictions. New results on Ddstar production and B -> Ddstar l nu are also presented. The evidence for a Dstarpr meson reported recently by DELPHI is not supported by OPAL and CLEO.

  2. Remains of mining in the territory of villages´ Červenica and Zlatá Baňa in the mountain range of Slanské vrchy

    Directory of Open Access Journals (Sweden)

    Rudolf Magula

    2007-10-01

    Full Text Available This article is devoted to the territory that is recondite for mining activities. It is situated in a north part of the mountain range of Slanské vrchy. There are villages that were known as mining villages in the past. The mining activities for gold, silver and mercury had only a local economical importance, beside of the output or production of opal. The output of opal on this territory was world noted, in the past. The aim of this article is to remit at some historical facts about former mines and to draw our attention to some attempts for building up, the educational and touristic path on this territory.

  3. The Effect of Network Geometry on Electron Transport in a Titanium Dioxide Photoanode of a Dye-sensitized Solar Cell

    Science.gov (United States)

    Mathew, Sonia Susan

    The dye sensitized solar cell (DSSC) is a photoelectrochemical cell that has garnered considerable attention because of its high efficiencies and potentially low production costs. The technology is based on a layer of mesoscopic TiO 2 particles, which significantly increases the optical path of the incident light that is harvested by the surface-anchored sensitizer molecules, whilst keeping an efficient contact with the electrolytic solution. The solar cell configuration that first achieved a high efficiency (˜7.5%) had a randomly connected network of titania nanoparticles, ruthenium polypyridyl complexes as the sensitizer, and an iodide/triiodide redox couple dissolved in an organic electrolyte. While the disordered nanoparticle network has a high surface area which maximizes the photogenerated electron density, the nanostructure also has a large number of surface states. These surface states act as traps and are known to limit the transport of electrons within such electrodes thereby hindering progress in achieving higher efficiencies. The structural disorder at the contact between two crystalline nanoparticles leads to enhanced scattering of free electrons, thus reducing electron mobility. An interconnected photoanode architecture offers the potential for improved electron transport by reducing the degree of disorder. This Thesis investigates the effect of the TiO2 network geometry on electron movement within the DSSC. In this regard, inverse opal structures with hexagonally close-packed pores and macroscopic (˜microm) order are synthesized and evaluated qualitatively and quantitatively (via FFT) with respect to their degree of interconnectedness. An inverse opal TiO2 electrode possesses advantages that supplement those of current disordered electrodes: (a) high surface area for dye adhesion, (b) large area contact between the sensitizer and the electrolyte, which aids electron transfer reactions, and (c) scattering of incident radiation due to the inherent

  4. F-35 Joint Strike Fighter (JSF) Program

    Science.gov (United States)

    2012-02-16

    strengthened airframe, and an arresting hook so as to permit catapult launches and arrested landings, as well as folding wing tips for more compact storage...80 Barbara Opall- Rome and David Pugliese, “Israeli Clarification Calms Canada’s Ire on Offsets

  5. ..... awe

    African Journals Online (AJOL)

    nutrition 'enpn.n' bur if if .. uadar how co .... che. Deparcmeat oIPaediatrica, Collep oIMedidae, MIIawL problem and . . if • lack 01 .... opal'" _d. ..... apparent effect of Nutriset on weight gain was particularly .... ments in vegetarian diets. Am J Clin ...

  6. Light-matter interaction in nanostructured materials

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst

    Se quantum dots in Si inverse opals showing that absorption has a limiting but not prohibitive effect. In addition, we discuss how the resonant nature of the phenomenon puts rather severe restrictions on the stabilization of the system in possible experiments. Last, we examine the influence on the decay...

  7. Measurement of the quark to photon fragmentation function through the inclusive production of prompt photons in hadronic $Z^0$ decays

    CERN Document Server

    Ackerstaff, K; Allison, J; Altekamp, N; Anderson, K J; Anderson, S; Arcelli, S; Asai, S; Axen, D; Azuelos, Georges; Ball, A H; Barberio, E; Barlow, R J; Bartoldus, R; Batley, J R; Baumann, S; Bechtluft, J; Beeston, C; Behnke, T; Bell, A N; Bell, K W; Bella, G; Bentvelsen, S; Bethke, S; Biebel, O; Biguzzi, A; Bird, S D; Blobel, Volker; Bloodworth, I J; Bloomer, J E; Bobinski, M; Bock, P; Bonacorsi, D; Boutemeur, M; Bouwens, B T; Braibant, S; Brigliadori, L; Brown, R M; Burckhart, H J; Burgard, C; Bürgin, R; Capiluppi, P; Carnegie, R K; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Chrisman, D; Clarke, P E L; Cohen, I; Conboy, J E; Cooke, O C; Cuffiani, M; Dado, S; Dallapiccola, C; Dallavalle, G M; Davis, R; De Jong, S; del Pozo, L A; Desch, K; Dienes, B; Dixit, M S; do Couto e Silva, E; Doucet, M; Duchovni, E; Duckeck, G; Duerdoth, I P; Eatough, D; Edwards, J E G; Estabrooks, P G; Evans, H G; Evans, M; Fabbri, F; Fanti, M; Faust, A A; Fiedler, F; Fierro, M; Fischer, H M; Fleck, I; Folman, R; Fong, D G; Foucher, M; Fürtjes, A; Futyan, D I; Gagnon, P; Gary, J W; Gascon, J; Gascon-Shotkin, S M; Geddes, N I; Geich-Gimbel, C; Geralis, T; Giacomelli, G; Giacomelli, P; Giacomelli, R; Gibson, V; Gibson, W R; Gingrich, D M; Glenzinski, D; Goldberg, J; Goodrick, M J; Gorn, W; Grandi, C; Gross, E; Grunhaus, J; Gruwé, M; Hajdu, C; Hanson, G G; Hansroul, M; Hapke, M; Hargrove, C K; Hart, P A; Hartmann, C; Hauschild, M; Hawkes, C M; Hawkings, R; Hemingway, R J; Herndon, M; Herten, G; Heuer, R D; Hildreth, M D; Hill, J C; Hillier, S J; Hobson, P R; Homer, R J; Honma, A K; Horváth, D; Hossain, K R; Howard, R; Hüntemeyer, P; Hutchcroft, D E; Igo-Kemenes, P; Imrie, D C; Ingram, M R; Ishii, K; Jawahery, A; Jeffreys, P W; Jeremie, H; Jimack, M; Joly, A; Jones, C R; Jones, G; Jones, M; Jost, U; Jovanovic, P; Junk, T R; Karlen, D; Kartvelishvili, V; Kawagoe, K; Kawamoto, T; Kayal, P I; Keeler, R K; Kellogg, R G; Kennedy, B W; Kirk, J; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Koetke, D S; Kokott, T P; Kolrep, M; Komamiya, S; Kress, T; Krieger, P; Von Krogh, J; Kyberd, P; Lafferty, G D; Lahmann, R; Lai, W P; Lanske, D; Lauber, J; Lautenschlager, S R; Layter, J G; Lazic, D; Lee, A M; Lefebvre, E; Lellouch, D; Letts, J; Levinson, L; Lloyd, S L; Loebinger, F K; Long, G D; Losty, M J; Ludwig, J; Macchiolo, A; MacPherson, A; Mannelli, M; Marcellini, S; Markus, C; Martin, A J; Martin, J P; Martínez, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J; McKigney, E A; McMahon, T J; McPherson, R A; Meijers, F; Menke, S; Merritt, F S; Mes, H; Meyer, J; Michelini, A; Mikenberg, G; Miller, D J; Mincer, A; Mir, R; Mohr, W; Montanari, A; Mori, T; Morii, M; Müller, U; Mihara, S; Nagai, K; Nakamura, I; Neal, H A; Nellen, B; Nisius, R; O'Neale, S W; Oakham, F G; Odorici, F; Ögren, H O; Oh, A; Oldershaw, N J; Oreglia, M J; Orito, S; Plinks, J; Pásztor, G; Pater, J R; Patrick, G N; Patt, J; Pearce, M J; Pérez-Ochoa, R; Petzold, S; Pfeifenschneider, P; Pilcher, J E; Pinfold, J L; Plane, D E; Poffenberger, P; Poli, B; Posthaus, A; Rees, D L; Rigby, D; Robertson, S; Robins, S A; Rodning, N; Roney, J M; Rooke, A M; Ros, E; Rossi, A M; Routenburg, P; Rozen, Y; Runge, K; Runólfsson, O; Ruppel, U; Rust, D R; Rylko, R; Sachs, K; Saeki, T; Sarkisyan-Grinbaum, E; Sbarra, C; Schaile, A D; Schaile, O; Scharf, F; Scharff-Hansen, P; Schenk, P; Schieck, J; Schleper, P; Schmitt, B; Schmitt, S; Schöning, A; Schröder, M; Schultz-Coulon, H C; Schumacher, M; Schwick, C; Scott, W G; Shears, T G; Shen, B C; Shepherd-Themistocleous, C H; Sherwood, P; Siroli, G P; Sittler, A; Skillman, A; Skuja, A; Smith, A M; Snow, G A; Sobie, R J; Söldner-Rembold, S; Springer, R W; Sproston, M; Stephens, K; Steuerer, J; Stockhausen, o B; Stoll, K; Strom, D; Szymanski, P; Tafirout, R; Talbot, S D; Tanaka, S; Taras, P; Tarem, S; Teuscher, R; Thiergen, M; Thomson, M A; Von Törne, E; Towers, S; Trigger, I; Trócsányi, Z L; Tsur, E; Turcot, A S; Turner-Watson, M F; Utzat, P; Van Kooten, R; Verzocchi, M; Vikas, P; Vokurka, E H; Voss, H; Wckerle, F; Wagner, A; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, a N K; Wells, P S; Wermes, N; White, J S; Wilkens, B; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Yekutieli, G; Zacek, V; Zer-Zion, D

    1998-01-01

    The inclusive production of prompt photons with energy above 10 GeV is measured using the OPAL detector in hadronic Z^0 decays at LEP. In contrast to previous measurements, the prompt photons were not required to be isolated. The production rate and energy spectrum are found to be in agreement with QCD predictions for the quark-to-photon fragmentation function.

  8. Smart Energy Systems Laboratory - A Real-Time Control, ICT and Power HIL platform

    DEFF Research Database (Denmark)

    Iov, Florin; Petersen, Lennart

    using a complete low voltage grid implementation in Opal-RT. Moreover, results for hierarchical power balancing and voltage control involving assets connected to MV and LV distribution system are shown. Finally, on-going activities regarding voltage control of large wind power plants are presented....

  9. Fractional decay of quantum dots in real photonic crystals

    DEFF Research Database (Denmark)

    Kristensen, Philip Trøst; Koenderink, A. Femius; Lodahl, Peter;

    2008-01-01

    We show that fractional decay may be observable in experiments using quantum dots and photonic crystals with parameters that are currently achievable. We focus on the case of inverse opal photonic crystals and locate the position in the crystal where the effect is most pronounced. Furthermore, we...

  10. Installation of NA62 Large Angle Veto detectors

    CERN Multimedia

    2012-01-01

    In May 2012, the NA62 collaboration has installed the first eight (out of 12) Large Angle Veto detectors for the accurate identification of photons. These subdetectors will re-use 3000 lead glass crystals with attached photomultipliers from the OPAL experiment at LEP – CERN’s former accelerator.

  11. Installation du détecteur NA62 Large Angle Veto

    CERN Multimedia

    2012-01-01

    In May 2012, the NA62 collaboration has installed the first eight (out of 12) Large Angle Veto detectors for the accurate identification of photons. These subdetectors will re-use 3000 lead glass crystals with attached photomultipliers from the OPAL experiment at LEP – CERN’s former accelerator.

  12. Three-dimensional photonic crystal intermediate reflectors for enhanced light-trapping in tandem solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Uepping, Johannes; Bielawny, Andreas; Wehrspohn, Ralf B. [Institute of Physics, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany); Fraunhofer-Institute for Mechanics of Materials, Halle (Germany); Beckers, Thomas; Carius, Reinhard; Rau, Uwe [Institute of Energy and Climate Research 5 - Photovoltaics, Forschungszentrum Juelich GmbH, Juelich (Germany); Fahr, Stefan; Rockstuhl, Carsten; Lederer, Falk [Institute of Condensed Matter Theory and Solid State Optics and Abbe Center of Photonics, Friedrich-Schiller-Universitaet Jena (Germany); Kroll, Matthias; Pertsch, Thomas [Institute of Applied Physics, Friedrich-Schiller-Universitaet Jena (Germany); Steidl, Lorenz; Zentel, Rudolf [Institute of Organic Chemistry, Johannes Gutenberg-Universitaet Mainz (Germany)

    2011-09-08

    A three-dimensional photonic crystal intermediate reflector for enhanced light trapping in tandem solar cells is presented. The intermediate reflector consists of a transparent and conductive ZnO:Al inverted opal sandwiched in between the top amorphous silicon and bottom microcrystalline silicon cell. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Selective incorporation of 5-hydroxytryptophan into proteins in mammalian cells

    Science.gov (United States)

    Zhang, Zhiwen; Alfonta, Lital; Schultz, Peter G

    2014-02-25

    This invention provides methods and compositions for incorporation of an unnatural amino acid into a peptide using an orthogonal aminoacyl tRNA synthetase/tRNA pair. In particular, an orthogonal pair is provided to incorporate 5-hydroxy-L-tryptophan in a position encoded by an opal mutation.

  14. Mineralization of fossil wood

    NARCIS (Netherlands)

    Buurman, P.

    1972-01-01

    Several pieces of fossil wood have been analyzed with X-ray diffraction and were grouped on the basis of mineralogical composition. Various mineralizations were studied in thin sections and by means of the scanning electron microscope. Wood-opals appear to show a structure preservation that points t

  15. Band Structure of Photonic Crystals Fabricated by Two-Photon Polymerization

    Directory of Open Access Journals (Sweden)

    Mikhail V. Rybin

    2015-01-01

    Full Text Available We study theoretically the band-gap structures of several types of three-dimensional photonic crystals with the fcc lattice symmetry: synthetic opals, inverted yablonovite and woodpile. The samples of inverted yablonovite, inverted yablonovite with a glassy superstructure and woodpile are fabricated by two-photon polymerization through a direct laser writing technique, which allows the creation of complex three-dimensional photonic crystals with a resolution better than 100 nm. A material is polymerized along the trace of a moving laser focus, thus enabling the fabrication of any desirable three-dimensional structure by direct “recording” into the volume of a photosensitive material. The correspondence of the structures of the fabricated samples to the expected fcc lattices is confirmed by scanning electron microscopy. We discuss theoretically how the complete photonic band-gap is modified by structural and dielectric parameters. We demonstrate that the photonic properties of opal and yablonovite are opposite: the complete photonic band gap appears in the inverted opal, and direct yablonovite is absent in direct opal and inverted yablonovite.

  16. Effect of type and concentration of ballasting particles on sinking rate of marine snow produced by the Appendicularian Oikopleura dioica

    DEFF Research Database (Denmark)

    Lombard, Fabien; Guidi, L.; Kiørboe, Thomas

    2013-01-01

    Ballast material (organic, opal, calcite, lithogenic) is suggested to affect sinking speed of aggregates in the ocean. Here, we tested this hypothesis by incubating appendicularians in suspensions of different algae or Saharan dust, and observing the sinking speed of the marine snow formed by the...

  17. SOFTWARE FOR SIMULATION OF TECHNOLOGICAL ADAPTATION OF THE OPTICAL INSTRUMENTS SYSTEMS

    Directory of Open Access Journals (Sweden)

    N. K. Artioukhina

    2012-01-01

    Full Text Available Programs for calculation and analysis of optical systems of any class are provides. The most effective was to combine the programs into a complex with the general system of mathematical models. A characteristic feature is to unify the exchange of information between these programs and software systems Opal and Zemax.

  18. Mapping of ice, snow and water using aircraft-mounted LiDAR

    Science.gov (United States)

    Church, Philip; Matheson, Justin; Owens, Brett

    2016-05-01

    Neptec Technologies Corp. has developed a family of obscurant-penetrating 3D laser scanners (OPAL 2.0) that are being adapted for airborne platforms for operations in Degraded Visual Environments (DVE). The OPAL uses a scanning mechanism based on the Risley prism pair. Data acquisition rates can go as high as 200kHz for ranges within 240m and 25kHz for ranges exceeding 240m. The scan patterns are created by rotating two prisms under independent motor control producing a conical Field-Of-View (FOV). An OPAL laser scanner with 90° FOV was installed on a Navajo aircraft, looking down through an aperture in the aircraft floor. The rotation speeds of the Risley prisms were selected to optimize a uniformity of the data samples distribution on the ground. Flight patterns simulating a landing approach over snow and ice in an unprepared Arctic environment were also performed to evaluate the capability of the OPAL LiDAR to map snow and ice elevation distribution in real-time and highlight potential obstacles. Data was also collected to evaluate the detection of wires when flying over water, snow and ice. Main results and conclusions obtained from the flight data analysis are presented.

  19. Biological productivity, terrigenous influence and noncrustal elements supply to the Central Indian Ocean Basin: Paleoceanography during the past approx. 1 Ma

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Masuzawa, T.; Borole, D.V.; Parthiban, G.; Jauhari, P.; Yamamoto, M.

    A 2 m-long sediment core from the siliceous ooze domain in the Central Indian Ocean Basin (CIOB; 13 degrees 03'S: 74 degrees 44'E; water depth 5099 m) is studied for calcium carbonate, total organic carbon, total nitrogen, biogenic opal, major...

  20. Productivity fluctuations in the southeastern Arabian Sea during the last 140 ka

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Toshiyuki Masuzawab; Naidu, P.D.; Parthiban, G.; Mineko Yamamoto

    the palaeoproductivity fluctuations over the last 140 ka. High calcium carbonate, biogenic opal, biogenic Ba contents (wt%) and their mass accumulation rates (g/cm u2/ka) suggest higher productivity during major interglacials than in the glacials. Organic carbon content...

  1. Variable dislocation widths in colloidal crystals of soft thermosensitive spheres

    NARCIS (Netherlands)

    Hilhorst, J.; Petukhov, A.V.

    2011-01-01

    Themagnetic and structural properties of a cobalt inverse opal-like crystal have been studied by a combination of complementary techniques ranging from polarized neutron scattering and superconducting quantum interference device (SQUID) magnetometry to x-ray diffraction. Microradian small-angle x-ra

  2. Ultrasmall-angle X-ray scattering analysis of photonic crystal structure

    NARCIS (Netherlands)

    Abramova, V.V.; Sinitskii, A.S.; Grigoryeva, N.A.; Grigoriev, S.V.; Belov, D.V.; Petukhov, A.V.; Mistonov, A.A.; Vasilieva, A.V.; Tretyakov, Y.D.

    2009-01-01

    The results of an ultrasmall angle X ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily disti

  3. Steve O'Neale 1948 - 2003

    CERN Document Server

    2003-01-01

    Colleagues and friends in CERN and beyond regret the sudden death of Steve O'Neale. Steve had a wide-ranging career, which started with studies of neutrino interactions in bubble chambers, where he participated in the CERN and Fermilab programmes. He worked on many aspects of the geometrical reconstruction and fitting software. He also took part in an experiment using a tagged photon beam in a SLAC bubble chamber. A major part of his career was spent in OPAL, where his contributions were exceptional, both in quantity and in quality. He served as an Offline Coordinator for many years, and his mark can be found throughout OPAL's software environment. Hundreds of young scientists owe their starting careers to the care and dedication that Steve spent in the provision of a fully-working computing platform for OPAL. In parallel to his OPAL work, he contributed to Babar, to CERN's central software services, and to ATLAS. On ATLAS, Steve was initially responsible for the SLUG framework, but made his most significa...

  4. Bounds on the electromagnetic interactions of excited spin-3/2 leptons

    CERN Document Server

    Walsh, R

    1999-01-01

    We discuss possible deviations from QED produced by a virtual excited spin-3/2 lepton in the reaction $e^+e^- \\longrightarrow 2\\gamma$. Data recorded by the OPAL Collaboration at a c.m. energy $\\sqrt{s} = 183 GeV$ are used to establish bounds on the nonstandard-lepton mass and coupling strengths.

  5. Settling barium fluxes in the Arabian Sea: Critical evaluation of relationship with export production

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, T.M.B.; Ittekkot, V.; Shankar, R.; Guptha, M.V.S.

    observations show a strong linear correlation between Ba sub(excess) fluxes and biogenic opal and organic carbon (C sub(org)) fluxes, indicating a biogenic origin of particulate Ba. However, the correlation between biogenic and Ba sub(excess) fluxes...

  6. Pluktijdstip blauwe pruimenrassen : eindverslag met resultaten uit 2011 en 2012

    NARCIS (Netherlands)

    Poldervaart, G.; Meijer, H.

    2013-01-01

    Bij volledig blauwe rassen, zoals de Lazoet-rassen is het moment van rijping, in tegenstelling tot bijvoorbeeld Opal en Reine Victoria, niet aan de kleuromslag van de vruchten te zien. Het moment van rijping en daarmee het juiste moment van plukken is lastig vast te stellen. Tegelijkertijd is het vo

  7. Biological parameters of the non-target pest Aphis gossypii Glover ...

    African Journals Online (AJOL)

    Thiago Mota

    2013-04-17

    Apr 17, 2013 ... genetically modified cotton variety (Bt) NuOpal, on the biological parameters of a non-target pest, Aphis gossypii .... Aphids have an important role in food chains within ... noticed, they were compared using the t test at 5% probability. ..... herbivores feeding on transgenic maize and consequences for the.

  8. Burial diagenetic processes of clay mineral and non-clay mineral, quartz cementation and dissolution in sandstones and mudstones of the Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Kazerouni, Afsoon Moatari; Friis, Henrik; Svendsen, Johan Byskov

    reprecipitate as opal, quartz or other mineral phases inside the shale itself. The deep marine sandstones in the Siri Canyon, Danish North Sea, have been reported to import significant amounts of dissolve silica from adjacent Paleocene shales during early diagenesis, and the authigenesis of silica developed...

  9. Understanding Biodiversity through Collaborative Research

    Science.gov (United States)

    Forrer, Charlotte

    2010-01-01

    Science is exciting because it is so accessible to the enthusiastic beginner. However, there is still a separation between professional scientists and novices, even in relatively open fields such as natural history. To help overcome this, the Open Air Laboratories (OPAL) network is supporting projects that bring scientists, amateur experts and…

  10. 78 FR 40131 - Proposed Subsequent Arrangement

    Science.gov (United States)

    2013-07-03

    ... (ANSTO) in Lucas Heights, Sydney, Australia, to the Deposito de Materiales Nucleares (DEMANU) and/or... Aires, Argentina. The material, which is currently located at ANSTO's OPAL reactor, will be transferred to the CNEA DEMANU and/or DUE warehouses for storage. ANSTO originally obtained the material...

  11. Formation of the Upper Cretaceous cherts in northeastern Sinai, Egypt

    Science.gov (United States)

    Genedi, Adel

    1998-02-01

    The Upper Cretaceous cherts in northeast Sinai, Egypt are found as nodules, tabular sheets and continuous beds within the carbonate dominated successions. They occur in the Halal, Wata and Matulla Formations and become a very conspicuous constituent in the Sudr Chalk. The chert framework is typical of all interstratal structures and is of two types: spotted and brecciated forms. The chert is classified into a fossiliferous and nonfossiliferous variety. The first is likely either to form packstone-grainstone fabrics or to form wackestone fabrics. The packstone-grainstone fabric is interpreted as replacing platform carbonate deposits at relatively lower energy but in an oxygenated environment while the wackestone fabric chert replaces low energy deep water carbonates. This Upper Cretaceous silica cycle was dominated by inorganic reactions involving dissolved silica, and there is much evidence of secondary diagenetic silicification. This process would have started in early diagenesis as opal-A, opal-C and opal-CT precipitated from interstitial waters. Quartz represents the end product of recrystallisation. This transformation from metastable to stable silica phases is explained as a solid-solid diagenetic reaction as emphasised by δ18O. The nodular cherts have formed in coastal mixing zones with opal-CT and quartz supersaturation and calcite undersaturation. The source of silica of the deep water cherts cannot be explained by this mixing zone model and needs further study. On the other hand, there is no evidence of deposition of layered amorphous silica in either shallow or deep environments.

  12. Highly-Ordered Ferroelectric Photonic Crystals

    Institute of Scientific and Technical Information of China (English)

    Naomi Matsuura; Suxia Yang; Ping Sun; Harry E. Ruda

    2003-01-01

    Highly-ordered, ferroelectric, Pb-doped Ba0.7Sr0.3TiO3, inverse opal thin films were fabricated using a sol-gel spin coating technique. The excellent crystal quality is evident from the SEM images and the good agreement between the theory and experiments.

  13. Extending the Territory: From Open Educational Resources to Open Educational Practices

    Science.gov (United States)

    Ehlers, Ulf-Daniel

    2011-01-01

    This article examines the findings of the recent OPAL report "Beyond OER: Shifting Focus from Resources to Practices". In doing so, it defines current understanding of open educational resources and open educational practices, and highlights the shift from open content to open practice. The article includes a framework for supporting…

  14. Evidence of formation of glushinskite as a biomineral in a Cactaceae species.

    Science.gov (United States)

    Monje, Paula V; Baran, Enrique J

    2005-03-01

    The X-ray diffractometric and infrared spectroscopic investigation of crystalline material isolated from the Cactaceae species Opuntia ellisiana shows the presence of a very complex mineral composition, including whewellite (monohydrated calcium oxalate), opal (SiO2), calcite (CaCO3) and glushinskite (dihydrated magnesium oxalate). This is the first report of the presence of magnesium oxalate in plants.

  15. Identification of Meloidogyne incognita, M. javanica and M. arenaria using sequence characterised amplified region (SCAR) based PCR assays

    NARCIS (Netherlands)

    Zijlstra, C.; Donkers-Venne, T.H.M.; Fargette, M.

    2000-01-01

    Three randomly amplified polymorphic DNA (RAPD) markers, OPA-l2420,OPB-061200 and OPA-OI700. species specific to the root-knot nematode species Meloidogyrie arenaria, M. incogriita and M,ja vanica respectively, were identified. After sequencing these RAPD-PCR products, longer primers of 1s to 23 nuc

  16. Characterization and Biomimcry of Avian Nanostructured Tissues

    Science.gov (United States)

    2016-01-19

    selection often favours conspicuous colours, which can be achieved by maximizing their chromatic or achromatic contrast against the environment ...fast-paced courtship displays in a dim environment . Keywords: Animal coloration, inverse-opal, iridescence, Lepidothrix, manakin, ultra-white...34 these traits by females as males fly around in dim forest light conditions. Birds, like most animals, process achromatic and chromatic components of

  17. CERN Multimedia

    Laurent Guiraud

    1998-01-01

    In front of the control room of the Opal experiment at CERN's LEP electron-positron collider : centre, Masashi Akiba, international science programmes ccordinator of Japan's Monbusho ministry, flankedby Akinori Mori, first secretary of the Japanese mission to Geneva, and Sachio Komamiya of Tokyo. Japan recently announced a further contribution to CERN.

  18. Colour reconnection at LEP2

    CERN Document Server

    Abreu, P

    2002-01-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, ALEPH, DELPHI, L3 and OPAL, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method (D. Duchesneau, (2001)), are yet inconclusive. (22 refs).

  19. Colour Reconnection at LEPII

    CERN Document Server

    Abreu, P

    2001-01-01

    The preliminary results on the search of colour reconnection effects (CR) from the four experiments at LEP, Aleph, Delphi, L3 and Opal, are reviewed. Extreme models are excluded by studies of standard variables, and on going studies of a method first suggested by L3, the particle flow method, are yet inconclusive.

  20. Gemstones

    Science.gov (United States)

    Olson, D.W.

    2013-01-01

    The estimated value of natural gemstones produced from U.S. deposits during 2012 was $11.1 million, a slight increase from 2011. U.S. gemstone production included agate, amber, beryl, coral, garnet, jade, jasper, opal, pearl, quartz, sapphire, shell, topaz, tourmaline, turquoise and many other gem materials.

  1. Development of early diagenetic silica and quartz morphologies — Examples from the Siri Canyon, Danish North Sea

    DEFF Research Database (Denmark)

    Weibel, Rikke; Friis, Henrik; Kazerouni, Afsoon Moatari

    2010-01-01

    ); seen as coatings on the opal rims, both ordered and random. 3. Cavity overgrowth; found as quartz outgrowths in circular and angular cavities formed by dissolution of early authigenic phases. Angular cavities in the microquartz coatings origin from dissolution of clinoptilolite, possibly with a source...

  2. Company activities - central region

    Energy Technology Data Exchange (ETDEWEB)

    Ayling, G.

    2007-06-15

    The first section of the article gives an overview of exploration and new developments in the field of gold, nickel, diamond and opal mining in central Queensland. The second part looks at coal, coal seam gas and petroleum exploration and development projects in the area. 1 fig.

  3. Indiana University High Energy Physics, Task A. Technical progress report, 1992--1993

    Energy Technology Data Exchange (ETDEWEB)

    Brabson, B.; Crittenden, R.; Dzierba, A. [and others

    1993-10-01

    This report discusses research at Indians University on the following high energy physics experiments: A search for mesons with unusual quantum numbers; hadronic states produced in association with high-mass dimuons; FNAL E740 (D0); superconducting super collider; and OPAL experiment at CERN.

  4. Archaeological Investigations at Site 45-DO-285, Chief Joseph Dam Project, Washington.

    Science.gov (United States)

    1984-01-01

    Inadequate for many tool types. In 1979, when the liThic analysis wes completed at 45-D0-285, opal was not classified as a separate material. However...reptiles and amphibians. Houghton Miffl In, Boston. Wilmsen, E.N. 1970 Lithic analysis and cultural Inference: a paleo-Indian case. University of

  5. Eldfellite, NaFe(SO4)2, a new fumarolic mineral from Eldfell volcano, Iceland

    DEFF Research Database (Denmark)

    Balic Zunic, Tonci; Garavelli, A.; Acquafredda, P.

    2009-01-01

    A new mineral, eldfellite, was found among fumarolic encrustations collected in 1990 on the Eldfell volcano, Heimaey Island, Iceland. Associated minerals are ralstonite, anhydrite, gypsum, bassanite, hematite, opal and tamarugite, as well as a presumably new mineral with the composition Na3Fe(SO4...

  6. LEP - Large Electron Positron Exhibition LEPFest 2000

    CERN Multimedia

    2000-01-01

    The Large Electron-Positron Collider (LEP) is 27 km long. Its four detectors (ALEPH, DELPHI, L3, OPAL) measure precisely what happens in the collisions of electrons and positrons. These conditions only exist-ed in the Universe when it was about 10 -10 sec old.

  7. Virtue Broadcasting - directorate change

    CERN Multimedia

    2003-01-01

    The Board of Virtue Broadcasting Plc ("Virtue") have announced the appointment of Mr. Klaus Ackerstaff as the CEO of the main Board. He began his professional career at CERN, where he was responsible for the IT infrastructure of the OPAL (particle physics) project (1/2 page).

  8. Major, trace, and rare earth elements in the sediments of the Central Indian Ocean Basin: Their source and distribution

    Digital Repository Service at National Institute of Oceanography (India)

    Pattan, J.N.; Jauhari, P.

    positive correlation with each other suggesting their association with a single authigenic phase such as Mn oxide. Biogenic opal contributes 30-50% of the total silica in the siliceous sediment. Aluminum, Fe, and K have contributed greater than 60 % from...

  9. Non-immunogenicity of overlapping gag peptides pulsed on autologous cells after vaccination of HIV infected individuals.

    Directory of Open Access Journals (Sweden)

    Henrik N Kløverpris

    Full Text Available BACKGROUND: HIV Gag-specific CD4+ and CD8+ T-cell responses are important for HIV immune control. Pulsing overlapping Gag peptides on autologous lymphocytes (OPAL has proven immunogenic and effective in reducing viral loads in multiple pigtail macaque studies, warranting clinical evaluation. METHODOLOGY: We performed a phase I, single centre, placebo-controlled, double-blinded and dose-escalating study to evaluate the safety and preliminary immunogenicity of a novel therapeutic vaccine approach 'OPAL-HIV-Gag(c'. This vaccine is comprised of 120 15mer peptides, overlapping by 11 amino acids, spanning the HIV Gag C clade sequence proteome, pulsed on white blood cells enriched from whole blood using a closed system, followed by intravenous reinfusion. Patients with undetectable HIV viral loads (<50 copies/ml plasma on HAART received four administrations at week 0, 4, 8 and 12, and were followed up for 12 weeks post-treatment. Twenty-three people were enrolled in four groups: 12 mg (n = 6, 24 mg (n = 7, 48 mg (n = 2 or matching placebo (n = 8 with 18 immunologically evaluable. T-cell immunogenicity was assessed by IFNγ ELIspot and intracellular cytokine staining (ICS. RESULTS: The OPAL-HIV-Gag(c peptides were antigenic in vitro in 17/17 subjects. After vaccination with OPAL-HIV-Gag(c, 1/6 subjects at 12 mg and 1/6 subjects at 24 mg dose groups had a 2- and 3-fold increase in ELIspot magnitudes from baseline, respectively, of Gag-specific CD8+ T-cells at week 14, compared to 0/6 subjects in the placebo group. No Gag-specific CD4+ T-cell responses or overall change in Rev, Nef, Tat and CMV specific responses were detected. Marked, transient and self-limiting lymphopenia was observed immediately post-vaccination (4 hours in OPAL-HIV-Gag(c but not in placebo recipients, with median fall from 1.72 to 0.67 million lymphocytes/mL for active groups (P<0.001, compared to post-placebo from 1.70 to 1.56 lymphocytes/ml (P = 0.16. CONCLUSION

  10. Improvements in the equation of state for the partially ionized plasmas of the solar interior

    Science.gov (United States)

    Liang, Aihua

    2005-11-01

    The three major material properties relevant for solar and stellar modeling are the equation of state (EOS), opacity and the nuclear reaction rate. Due to the nature of the equations of stellar structure and evolution, in most parts of a stars interior, the three material properties are entangled, and it is difficult to use astrophysics to constrain a single one. Luckily, thanks to the adiabatic stratification of the convection zone, there the structure only depends on the EOS, which is therefore largely disentangled from the other quantities. Our research, which aims at constraining the EOS using information from the Sun, is therefore most successful when data from the convection zone are used. Among the many solar equations of state that are being currently used there are two popular ones: Mihalas-Däppen-Hummer (MHD) EOS and OPAL EOS. Helioseismic inversion procedures, which have become standard to evaluate the accuracy of different solar models with respect to the real Sun, have revealed that except for the top 2%, the OPAL EOS matches the solar observations better than the MHD EOS. For this reason we have set our research goal to find a modification of the MHD EOS that can, in a first step, simulate the OPAL EOS, and ultimately, the real Sun. This goal has been attained. By construction, the OPAL EOS contains higher order correlation terms which are missing in the MHD EOS. Through an inversion procedure from the activity series expansion (ACTEX), upon which the OPAL EOS is based to the free energy expression of the MHD EOS, we have found out that the free particle assumption, used in the original version of the MHD EOS has indeed to be abandoned. We show that the two-body scattering terms of the Coulomb interaction, as well as electron degeneracy play a significant role in the difference between the original version of the MHD and OPAL EOS. During our interdisciplinary investigation, aiming at seeking an improved MHD EOS under the guidance of the OPAL EOS, we

  11. Epiglottis cross-sectional area and oropharyngeal airway length in male and female obstructive sleep apnea patients

    Directory of Open Access Journals (Sweden)

    Ma MA

    2016-10-01

    Full Text Available Melinda A Ma,1 Rajesh Kumar,2–4 Paul M Macey,4,5 Frisca L Yan-Go,6 Ronald M Harper,1,4 1Department of Neurobiology, 2Department of Anesthesiology, 3Department of Radiological Sciences, David Geffen School of Medicine, 4Brain Research Institute, 5UCLA School of Nursing, 6Department of Neurology, David Geffen School ofMedicine, University of California at Los Angeles, Los Angeles, CA, USA Introduction: Obstructive sleep apnea (OSA is a male-predominant condition, characterized by repeated upper-airway collapse with continued diaphragmatic efforts during sleep, and is accompanied by severe physiological consequences. Multiple morphological aspects, including epiglottis cross-sectional area (CSA and oropharyngeal airway length (OPAL, can contribute to airway collapsibility in the condition. This study focused on the effects of OSA severity, sex, and race on OPA dimensions.Materials and methods: Two high-resolution T1-weighted image series were collected from 40 mild-to-severe OSA subjects (age 46.9±9 years, body mass index 30.4±5.4 kg/m2, Apnea–Hypopnea Index score 32.8±22.5, 28 males and 54 control subjects (47±9 years, 24.7±3.8 kg/m2, 32 males using a 3 T magnetic resonance-imaging scanner. Caucasian, Asian, African-American, and “other” subjects constituted the study pool. Both image series were realigned and averaged, and reoriented to a common space. CSA and OPAL were measured, normalized for subject height, and compared between sexes and disease-severity levels in OSA and control subjects.Results: Significantly reduced epiglottis CSA appeared only in severe OSA vs controls (P=0.009. OPAL increased significantly with OSA severity vs controls (mild, P=0.027; moderate, P<0.001; severe, P<0.001. OSA males showed increased CSA and greater OPAL than OSA females, which may underlie the increased proportion of affected males with higher apnea–hypopnea index scores. However, no significant differences appeared between CSA and OPAL

  12. Sea Surface Temperature, Productivity, and Terrestrial Flux Variations of the Southeastern South China Sea over the Past 800000 Years (IMAGESMD972142

    Directory of Open Access Journals (Sweden)

    Liang-Jian Shiau

    2008-01-01

    Full Text Available Variations in sea surface temperature (SST, productivity, and biogenic components such as total organic carbon (TOC, carbonate, and opal contents measured from IMAGES (International Marine Global Changes Study core MD972142 provide information about long-term paleoceanographic changes during the past ~870000 years in the southeastern South China Sea (SCS. MD972142 U37k' -SSTs varied from 25 to 29_C, paralleling the glacial to interglacial changes. MD972142 biogenic components show relatively high carbonate and opal, and low TOC contents in interglacial stages, and low carbonate and opal and high TOC contents in glacial stages, and these variations appear to be sensitive to regional terrestrial sediment input and productivity. Our analysis indicates that the MD972142 carbonate record is primarily controlled by terrestrial sediment inputs that are associated with sea level fluctuations during past glacial-interglacial stages. The TOC record reflects past glacial-interglacial changes in both monsoon-induced productivity and terrestrial organic matter input in the SCS. The TOC record exhibits several short-term peaks that are associated with lower U37 k' -SSTs (especially in MIS 2 - 4, 10, 12, perhaps implying a much strengthened winter monsoon. The opal record shows relatively high content in most interglacial stages, which appears to be linked to increased summer monsoon upwelling or increased siliceous sediment input by more precipitation and river runoff during warm climate conditions. The TOC and opal contents both show long-term increasing trends since the mid-Brunhes, most noticeably from ~330 kya. The long-term trends observed in this study are most likely attributable to changes in SCS hydrography, productivity, and/or preservation in response to the increased strength of the East Asian monsoon system on possibly tectonic timescales.

  13. Comparison of shear bond strength of orthodontic brackets bonded using two different hydrophilic primers: An in vitro study

    Directory of Open Access Journals (Sweden)

    M Kumaraswamy Anand

    2014-01-01

    Full Text Available Context: Salivary control and maintenance of a dry operating field is a prime requisite of orthodontic bonding. Moisture insensitive primer (MIP with a clinical significant bond strength values have a better edge over the conventional hydrophobic bonding systems. Aim: The aim of this study is to investigate the effectiveness of two hydrophilic primers with respect to conventional hydrophobic primer by comparing their shear bond strength (SBS and adhesive-failure locations after contamination with saliva and saliva substitute. Materials and Methods: A total of 150 extracted human premolars were randomly divided into five group s ; Group A (Transbond MIP/saliva substitute, Group B (Opal Primo/saliva substitute, Group C (Transbond MIP/natural saliva, Group D (Opal Primo/natural saliva, control group - Group E (Transbond XT/dry, adhesive-Transbond XT used for all five groups and bonded using stainless steel brackets. Shear forces were applied to the samples with a universal testing machine. SBSs was measured in megapascals. The mode of bond failure was determined using the adhesive remnant index (ARI. Results: The mean SBS produced by Transbond MIP was higher than Opal Primo, which was statistically significant according to one-way analysis of variance. Both the tested groups showed lesser bond strength values than Transbond XT (the control. ARI scores revealed that there was no statistically significant difference in the site of bond failure between study groups. ARI scores were found to be lower for study groups suggesting adhesive failure, compared to higher ARI scores for the control group suggesting cohesive failure. Conclusion: Transbond XT adhesive with Transbond MIP or Opal Primo have clinically acceptable bond strength in wet fields. Opal Primo is a viable option to use as a hydrophilic primer clinically.

  14. Optical Profiling of the Atmospheric Limb CubeSat Experiment

    Science.gov (United States)

    Jeppesen, M.; Taylor, M. J.; Swenson, C.; Marchant, A.

    2014-12-01

    The Earth's lower thermosphere is an important interface region between the neutral atmosphere and the "space weather" environment. While the high-latitude region of the thermosphere responds promptly to energy inputs, relatively little is known about the global/regional response to these energy inputs. Global temperatures are predicted to respond within 3-6 hours, but the details of the thermal response of the atmosphere as energy transports away from high-latitude source regions is not well understood. The Optical Profiling of the Atmospheric Limb (OPAL) mission aims to characterize this thermal response through observation of the temperature structure of the lower thermosphere at mid- and low-latitudes. The OPAL instrument is designed to map global thermospheric temperature variability over the critical "thermospheric gap" region (~100-140 km altitude) by spectroscopic analysis of molecular oxygen A-band emission (758 - 768 nm). The OPAL instrument is a grating-based imaging spectrometer with refractive optics and a high-efficiency volume holographic grating (VHG). The scene is sampled by 7 parallel slits that form non-overlapping spectral profiles at the focal plane with resolution of 0.5 nm (spectral), 1.5 km (limb profiling), and 60 km (horizontal sampling). A CCD camera at the instrument focal plane delivers low noise and high sensitivity. The instrument is designed to strongly reject stray light from daylight regions of the earth. The OPAL mission is funded by the National Science Foundation (NSF) CubeSat-based Science Missions for Geospace and Atmospheric Research program. The OPAL instrument and mission will be designed, built and executed by a team comprised of students and professors from Utah State University, Dixie State University and the University of Maryland Eastern Shore, with support from professional scientists and engineers from the Space Dynamics Laboratory and Hawk Institute for Space Science.

  15. Ballast minerals and the sinking carbon flux in the ocean: carbon-specific respiration rates and sinking velocity of marine snow aggregates

    Directory of Open Access Journals (Sweden)

    M. H. Iversen

    2010-09-01

    Full Text Available Recent observations have shown that fluxes of ballast minerals (calcium carbonate, opal, and lithogenic material and organic carbon fluxes are closely correlated in the bathypelagic zones of the ocean. Hence it has been hypothesized that incorporation of biogenic minerals within marine aggregates could either protect the organic matter from decomposition and/or increase the sinking velocity via ballasting of the aggregates. Here we present the first combined data on size, sinking velocity, carbon-specific respiration rate, and composition measured directly in three aggregate types; Emiliania huxleyi aggregates (carbonate ballasted, Skeletonema costatum aggregates (opal ballasted, and aggregates made from a mix of both E. huxleyi and S. costatum (carbonate and opal ballasted. Overall average carbon-specific respiration rate was ~0.13 d−1 and did not vary with aggregate type and size. Ballasting from carbonate resulted in 2- to 2.5-fold higher sinking velocities than those of aggregates ballasted by opal. We compiled literature data on carbon-specific respiration rate and sinking velocity measured in aggregates of different composition and sources. Compiled carbon-specific respiration rates (including this study vary between 0.08 d−1 and 0.20 d−1. Sinking velocity increases with increasing aggregate size within homogeneous sources of aggregates. When compared across different particle and aggregate sources, however, sinking velocity appeared to be independent of particle or aggregate size. The carbon-specific respiration rate per meter settled varied between 0.0002 m−1 and 0.0030 m−1, and decreased with increasing aggregate size. It was lower for calcite ballasted aggregates as compared to that of similar sized opal ballasted aggregates.

  16. Photonic crystal coupled TiO(2)/polymer hybrid for efficient photocatalysis under visible light irradiation.

    Science.gov (United States)

    Liao, Gaozu; Chen, Shuo; Quan, Xie; Chen, Huan; Zhang, Yaobin

    2010-05-01

    Inverse TiO(2) opal photonic crystal coupled TiO(2)/poly(3-hexylthiophene) (bilayer TiO(2)/P3HT) was structured on FTO substrate for efficient photocatalysis under visible light irradiation (lambda > 400 nm). We expected that the photocatalytic capability of this hybrid photocatalyst could be enhanced by the efficient visible light absorption owing to the photonic crystal structure and effective charge separation owing to the unique heterojunction built between TiO(2) and P3HT. The bilayer TiO(2)/P3HT photocatalyst was prepared first by depositing inverse TiO(2) opal on FTO substrate via replicating polystyrene opal, followed by spin coating a layer of TiO(2) nanoparticles on the inverse TiO(2) opal. The as prepared bilayer TiO(2) was modified by P3HT via dipping method. Environmental scanning electron microscopy (ESEM) images demonstrated that the as prepared photocatalyst was composed of inverse TiO(2) opal layer and TiO(2) nanoparticles layer. The UV-vis diffuse reflectance spectra showed that the optical absorption for bilayer TiO(2)/P3HT was more intensive than for pristine TiO(2) nanoparticle/P3HT (NP-TiO(2)/P3HT) in the range of 400-650 nm. The enhanced generation of photocurrent under visible light irradiation (lambda > 400 nm) was observed using the bilayer TiO(2)/P3HT. The results of photocatalytic experiments under visible light irradiation revealed that the pseudofirst-order kinetic constant of photocatalytic degradation of methylene blue using the bilayer TiO(2)/P3HT was 2.08 times as great as that using NP-TiO(2)/P3HT, showing the advantage of the unique structure in the bilayer TiO(2)/P3HT for efficient photocatalysis.

  17. The silicon isotope record of early silica diagenesis

    Science.gov (United States)

    Tatzel, Michael; von Blanckenburg, Friedhelm; Oelze, Marcus; Schuessler, Jan A.; Bohrmann, Gerhard

    2015-10-01

    The heavy isotopes of silicon are strongly enriched in some of the youngest, early diagenetically formed porcellanite layers from the Southwest Indian Ridge (Pleistocene) and the Maud Rise (Pliocene). These porcellanite layers are composed of opal-CT and were formed by the conversion of amorphous silica (opal-A) from siliceous sediment via dissolution-reprecipitation. Their bulk δ30Si values range between 1.7 and 2.3‰. Detritus-poor siliceous sediment surrounding these layers is significantly lower at -0.3 to 1.5‰. Sequential chemical extractions of bulk siliceous sediment show (i) preferential dissolution of diatoms featuring higher δ30Si than radiolaria and Al-Si components. The detailed investigation of porcellanite layers by micro-scale Si isotope and Al/Si analyses using UV femtosecond laser ablation ICP mass spectrometry show that (ii) precipitation of authigenic aluminum silicates enriched in light Si isotopes drives pore waters to even higher δ30Si. We suggest that the same processes redistributed stable silicon isotopes in precursor siliceous sediments of ancient chert. We infer that past environmental conditions can be reconstructed with high fidelity from the stable Si isotope composition of chert when initial seawater Si concentrations were high (such as in the Precambrian). Exchange of Si between layers during phase transformation (from opal-A to opal-CT and from opal-CT to quartz) is impeded when variable amounts of detrital minerals are present, because they control rates of silica phase transformation and hence the timing of dissolution-reprecipitation during burial.

  18. Ultra-wideband fiber optical parametric amplifier for spectrally-encoded microscopy (Conference Presentation)

    Science.gov (United States)

    Wei, Xiaoming; Tan, Sisi; Mussot, Arnaud; Kudlinski, Alexandre; Tsia, Kevin K.; Wong, Kenneth

    2016-03-01

    Fiber optical parametric amplifier (FOPA) has gained its popularity in the telecommunication systems at the 1.5-um window for its gain, bandwidth etc. Unfortunately, its practical application at the bio-favorable window, i.e. 1.0 um, still requires substantial efforts. Thus, here we report a versatile all-fiber optical parametric amplifier for life-science (OPALS) at 1.0 um as an add-on module for optical imaging system. The parametric gain fiber (photonic-crystal fiber (PCF), 110 m in length) is specially designed to reduce the longitudinal dispersion fluctuation, which yields a superior figure of merit, i.e. a total insertion loss of ~2.5 dB and a nonlinear coefficient of 34 /(W•km). Our OPALS delivers a superior performance in terms of gain (~158,000), bandwidth (>100 nm) and gain flatness (Experimentally, we show that: 1) a wavelength-varying quasi-monochrome pump achieves a 52-dB gain and 160-nm bandwidth, but at the expense of a larger gain-spectrum ripple, i.e. a bell-shaped; 2) the birefringence of the parametric gain medium, i.e. PCF in this case, can be utilized to improve the gain-spectrum flatness of OPALS by 10.5 dB, meanwhile a 100-nm bandwidth can be guaranteed; 3) the gain-spectrum flatness of OPALS can be further flattened by using a high-speed wavelength-sweeping pump, which exhibits a 110-nm flat gain spectrum with ripple less than 3 dB. Finally, we employ this versatile all-fiber OPALS as an add-on module to enhance the sensitivity of a spectrally-encoded microscope by 47 dB over an ultra-wide spectral range.

  19. Millennial-scale Changes of Surface and Bottom Water Conditions in the Northwest Pacific during the Last Deglacial Period

    Science.gov (United States)

    Khim, B. K.; Kim, S.; Ikehara, K.; Itaki, T.; Shibahara, A.; Yamamoto, M.

    2015-12-01

    The last deglacial changes of the water column conditions in the Northwest Pacific were reconstructed using geochemical and isotope proxies (biogenic opal, CaCO3, total organic carbon (TOC), redox sensitive elements, bulk nitrogen isotopes (δ15N), and silicon isotopes (δ30Sidiatom) of diatom frustules) along with the published data (alkenone temperatures and benthic foraminiferal faunas) at core GH02-1030 recovered from the slope off Tokachi. Age model for core GH02-1030 was determined using both planktonic and benthic foraminiferal AMC 14C dates (Ikehara et al., 2006). Alkenone sea surface temperature (SST) shows that biogenic opal productivity was related to the degree of spring-summer mixed layer depth (MLD). Biogenic opal and TOC contents change almost in parallel. δ30Sidiatom values are high (~+1‰) during the Holocene and low (~-0.4‰) during the last glacial maximum. During the Bølling-Allerød (BA) and the Pre-Boreal (PB), silicic acid utilization represented by δ30Sidiatom increased when the biogenic opal productivity and export TOC productivity are high under shoaling of spring-summer MLD. The BA and the PB intervals contain laminated sediment layers, which are characterized by increases of CaCO3 contents, bulk δ15N values, and redox element concentrations (Mo/Al, Cd/Al, and U/Al). All these indicate low dissolved oxygen content of the bottom water during the BA and PB periods, which is supported by the good preservation of dysoxic benthic foraminifera. In addition, compared to the Holocene biogenic opal productivity and related silicic acid utilization, the high δ15N values during the BA and the PB seemed to be attributed more to denitrification through the water column rather than complete utilization of nitrate. Another distinct feature based on benthic foraminiferal assemblage, CaCO3 contents and redox element concentrations is that the dissolved oxygen content in bottom water was lower during the BA than the PB. Because biogenic opal

  20. $\\alpha_{s}$ from the (revised) ALEPH data for $\\tau$ decay

    CERN Document Server

    Boito, Diogo; Maltman, Kim; Osborne, James; Peris, Santiago

    2014-01-01

    We present a new analysis of $\\alpha_s$ from hadronic $\\tau$ decays based on the recently revised ALEPH data. The analysis is based on a strategy which we previously applied to the OPAL data. We critically compare our strategy to the one traditionally used and comment on the main differences. Our analysis yields the values $\\alpha_s(m_\\tau^2)=0.296\\pm 0.010$ using fixed-order perturbation theory, and $\\alpha_s(m_\\tau^2)=0.310\\pm 0.014$ using contour-improved perturbation theory. Averaging these values with our previously obtained values from the OPAL data, we find $\\alpha_s(m_\\tau^2)=0.303\\pm 0.009$, respectively, $\\alpha_s(m_\\tau^2)=0.319\\pm 0.012$, as the most reliable results for $\\alpha_s$ from $\\tau$ decays currently available.