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Sample records for optical compounds monosubstituted

  1. Molecular Modeling and Experimental Investigations of Nonlinear Optical Compounds Monosubstituted Derivatives of Dicyanovinylbenzene

    NASA Technical Reports Server (NTRS)

    Timofeeva, Tatiana V.; Nesterov, Vladimir N.; Antipin, Mikhail Yu.; Clark, Ronald D.; Sanghadasa, Mohan; Cardelino, Beatriz H.; Moore, Craig E.; Frazier, Donald O.

    1999-01-01

    A search for potential nonlinear optical compounds was performed using the Cambridge Structure Database and molecular modeling. We investigated a series of monosubstituted derivatives of dicyanovinylbenzene, since the nonlinear optical (NLO) properties of such derivatives (o-methoxy-dicyanovinylbenzene, DIVA) were studied earlier. The molecular geometry of these compounds was investigated with x-ray analysis and discussed along with the results of molecular mechanics and ab initio quantum chemical calculations. The influence of crystal packing on the planarity of the molecules of this series has been revealed. Two new compounds from the series studied, ortho-F and para-Cl-dicyanovinylbenzene, according to powder measurements, were found to be NLO compounds in the crystal state about 10 times more active than urea. The peculiarities of crystal structure formation in the framework of balance between van der Waals and electrostatic interactions have been discussed. The crystal shape of DIVA and two new NLO compounds have been calculated on the basis of the known crystal structure.

  2. Molecular Modeling and Experimental Study of Nonlinear Optical Compounds: Mono-Substituted Derivatives of Dicyanovinylbenzene

    NASA Technical Reports Server (NTRS)

    Timofeeva, Tatyana V.; Nesterov, Vladimir N.; Antipin, Mikhael Y.; Clark, R. D.; Sanghadasa, M.; Cardelino, B. H.; Moore, C. E.; Frazier, Donald O.

    2000-01-01

    A search for potential nonlinear optical (NLO) compounds has been performed using the Cambridge Structural Database and molecular modeling. We have studied a series of mono-substituted derivatives of dicyanovinylbenzene as the NLO properties of one of its derivatives (o-methoxy-dicyanovinylbenzene, DIVA) were described earlier. The molecular geometry in the series of the compounds studied was investigated with an X- ray analysis and discussed along with results of molecular mechanics and ab initio quantum chemical calculations. The influence of crystal packing on the molecular planarity has been revealed. Two new compounds from the series studied were found to be active for second harmonic generation (SHG) in the powder. The measurements of SHG efficiency have shown that the o-F- and p-Cl-derivatives of dicyanovinylbenzene are about 10 and 20- times more active than urea, respectively. The peculiarities of crystal structure formation in the framework of balance between the van der Waals and electrostatic interactions have been discussed. The crystal morphology of DIVA and two new SHG-active compounds have been calculated on the basis of their known crystal structures.

  3. Second- and third-order nonlinear optical properties of unsubstituted and mono-substituted chalcones

    NASA Astrophysics Data System (ADS)

    Abegão, Luis M. G.; Fonseca, Ruben D.; Santos, Francisco A.; Souza, Gabriela B.; Barreiros, André Luis B. S.; Barreiros, Marizeth L.; Alencar, M. A. R. C.; Mendonça, Cleber R.; Silva, Daniel L.; De Boni, Leonardo; Rodrigues, J. J.

    2016-03-01

    This work describes the second and third orders of nonlinear optics properties of unsubstituted chalcone (C15H12O) and mono-substituted chalcone (C16H14O2) in solution, using hyper-Rayleigh scattering and Z-Scan techniques to determine the first molecular hyperpolarizability (β) and the two-photon absorption (2PA) cross section respectively. β Values of 25.4 × 10-30 esu and 31.6 × 10-30 esu, for unsubstituted and mono-substituted chalcone, respectively, dissolved in methanol have been obtained. The highest values of 2PA cross-sections obtained were 9 GM and 14 GM for unsubstituted and mono-substituted chalcone, respectively. The experimental 2PA cross sections obtained for each chalcone are in good agreement with theoretical results.

  4. An ab initio study of the influence of substituents and intramolecular hydrogen bonding on the carbonyl bond length, and the harmonic and anharmonic stretching force constants. I. Monosubstituted carbonyl compounds

    NASA Astrophysics Data System (ADS)

    Bock, Charles W.; Trachtman, Mendel; George, Philip

    1981-11-01

    The CO bond length and the quadratic, cubic and quartic stretching force constants, calculated ab initio using the unscaled 4-31G basis set with full geometry optimization, are reported for three series of monosubstituted carbonyl compounds in which the atom directly bonded to the carbonyl carbon is another carbon, a nitrogen, or an oxygen atom, respectively. The data are analyzed in terms of the In ƒ versus In re relationship, and also the generalized power functions and exponential functions proposed by Herschbach and Laurie. Not only does the atom directly bonded to the carbonyl carbon affect the magnitude of re and the force constants, but the rest of the substituent group is found to be capable of exerting an even greater influence. Within each series of compounds the overall progression from the shortest to the longest CO bonds is tentatively attributed to a diminishing electron density in the bonding region.

  5. Compound semiconductor optical waveguide switch

    DOEpatents

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  6. Hybrid Pd/Fe{sub 3}O{sub 4} nanowires: Fabrication, characterization, optical properties and application as magnetically reusable catalyst for the synthesis of N-monosubstituted ureas under ligand-free conditions

    SciTech Connect

    Nasrollahzadeh, Mahmoud; Azarian, Abbas; Ehsani, Ali; Sajadi, S.Mohammad; Babaei, Ferydon

    2014-07-01

    Highlights: • Preparation of Pd/Fe{sub 3}O{sub 4} nanowires as magnetically reusable catalysts. • The optical properties of the catalyst were studied using Gans theory. • N-arylation of benzylurea and in situ hydrogenolysis of 1-benzyl-3-arylureas. - Abstract: This paper reports the synthesis and use of Pd/Fe{sub 3}O{sub 4} nanowires, as magnetically separable catalysts for ligand-free amidation coupling reactions of aryl halides with benzylurea under microwave irradiation. Then, the in situ hydrogenolysis of the products was performed to afford the N-monosubstituted ureas from good to excellent yields. This method has the advantages of high yields, simple methodology and easy work up. The catalyst can be recovered by using a magnet and reused several times without significant loss of its catalytic activity. The catalyst was characterized using the powder XRD, SEM, EDS and UV–vis spectroscopy. Experimental absorbance spectra was compared with results from the Gans theory.

  7. The structure of the first stable monosubstituted sulfur diimide.

    PubMed

    Jones, Ray

    2015-06-01

    The title compound, 4-(4-methylphenyl)-1,3-diaza-2,4-dithiabuta-1,2-diene, C7H8N2S2, was the first example of a stable monosubstituted sulfur diimide to be documented [Jones (1988). PhD thesis, Imperial College, University of London, England]. Although a partial description of this structure was published previously, the full details are presented here. This allows a detailed comparison against the only other example of this system published to date, highlighting differences in bonding, conformation and packing. PMID:26044326

  8. An AB initio study of the geometry of the CC(H) group the fCC 2 stretching force constant, and the fCC,inCC coupling constant in conjugated mono-substituted carbonyl compounds

    NASA Astrophysics Data System (ADS)

    Bock, Charles W.; Trachtman, Mendel; George, Philip

    1982-06-01

    The geometry of the CC(H)O group, the stretching force constant fCC 2, and the coupling constant fCO,CC, calculated using the unscaled 4-31G basis set with full geometry optimization, are reported for various planar mono-substituted carbonyl compounds. The trends in rCC, rCH, ∠CCO and ∠HCO as rCO increases are investigated, and an inverse relationship established between rCO and rCC, i.e. rCO X rCC = 1.782 ± 0.013. Linear relationships are found in the plot of In fCC 2 versus In rCC in accord with the general form of Clark's equation, and in the plot of fCO,CC versus the quotient rCOit/rinCC.

  9. An unusual mono-substituted Keggin anion-chain based 3D framework with 24-membered macrocycles as linker units

    SciTech Connect

    Pang Haijun; Ma Huiyuan; Yu Yan; Yang Ming; Xun Ye; Liu Bo

    2012-02-15

    A new compound, [Cu{sup I}(H{sub 2}O)(Hbpp){sub 2}] Subset-Of {l_brace}[Cu{sup I}(bpp)]{sub 2}[PW{sub 11}Cu{sup II}O{sub 39}]{r_brace} (1) (bpp=1,3-bis(4-pyridyl)propane), has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. In compound 1, the unusual -A-B-A-B- array mono-substituted Keggin anion-chains and 24-membered (Cubpp){sub 2} cation-macrocycles are linked together to form a (2, 4) connected 3D framework with channels of ca. 9.784 Multiplication-Sign 7.771 A{sup 2} along two directions, in which the [Cu(H{sub 2}O)(Hbpp){sub 2}] coordination fragments as guest components are trapped. The photocatalytic experiments of compound 1 were performed, which show a good catalytic activity of compound 1 for photodegradation of RhB. Furthermore, the IR, TGA and electrochemical properties of compound 1 were investigated. - Graphical abstract: An unusual example of mono-substituted Keggin anion-chain based hybrid compound that possesses a 3D structure has been synthesized, which offers a feasible route for synthesis of such compounds. Highlights: Black-Right-Pointing-Pointer The first example of -A-B-A-B- array mono-substituted Keggin chain is observed. Black-Right-Pointing-Pointer An unusual three dimensional structure based mono-substituted Keggin anion-chains. Black-Right-Pointing-Pointer The photocatalysis and electrochemical properties of the title compound were studied.

  10. Monosubstituted Benzene Derivatives from Fruits of Ficus hirta and Their Antifungal Activity against Phytopathogen Penicillium italicum.

    PubMed

    Wan, Chunpeng; Han, Jianxin; Chen, Chuying; Yao, Liangliang; Chen, Jinyin; Yuan, Tao

    2016-07-20

    Ficus hirta, a widely consumed food by Hakka people, has been reported to show potent antifungal activity against phytopathogen Penicillium italicum. However, there is no report of chemical constituents responsible for the antifungal activity. In the current study, nine monosubstituted benzene derivatives, including three new derivatives (1-3), were isolated from the fruits of F. hirta. The structures of these isolates were elucidated on the basis of the analysis of spectroscopic data (mass spectrometry and nuclear magnetic resonance). All of the isolates were evaluated for antifungal activities against P. italicum. At an equivalent concentration, compound 1 exhibited stronger antifungal activity than that of the ethanol extract of F. hirta fruits. PMID:27381890

  11. Optical remote sensing of atmospheric compounds

    NASA Astrophysics Data System (ADS)

    Vazquez, Gabriel J.

    1996-02-01

    Human activities are altering the earth system at the local, regional, and global scales. It is therefore of the utmost importance to track the workings of mother earth in order to detect any changes at their early stages so that appropriate actions are taken to understand, assess, control or prevent the adverse effects. A number of deleterious effects to the environment can, at least in part, be ascribed to air pollution, namely, the thinning of the ozone layer, the related increase in the occurrence of skin cancer, the warming of the earth system, photochemical smog, acid rain/fog, acidification of soils and waters, forest decline, etc. It is therefore necessary to monitor the most relevant processes of the earth's atmosphere, namely, the energy input, the dynamics and the chemistry. In this contribution I mainly focus on the latter, specifically, on the measurement/monitoring of atmospheric compounds. To understand atmospheric chemistry and air pollution it is necessary to have reliable and accurate values of the mixing ratios of the numerous atmospheric gases and of their diurnal/seasonal variations and long-term trends. In this contribution I present an overview of the most relevant optical remote sensing techniques that are rapidly becoming the methods of choice to probe the chemical composition and physical state of the atmosphere, especially when high selectivity, sensitivity and fast-time response are required.

  12. Field Evaluation of Anti-Biofouling Compounds on Optical Instrumentation

    NASA Technical Reports Server (NTRS)

    McLean, Scott; Schofield, Bryan; Zibordi, Giuseppe; Lewis, Marlon; Hooker, Stanford; Weidemann, Alan

    1997-01-01

    Biofouling has been a serious question in the stability of optical measurements in the ocean, particularly in moored and drifting buoy applications. Many investigators coat optical surfaces with various compounds to reduce the amount of fouling; to our knowledge, however, there are no objective, in-situ comparative testing of these compounds to evaluate their effectiveness with respect to optical stability relative to untreated controls. We have tested a wide range of compounds at in-situ locations in Halifax Harbour and in the Adriatic Sea on passive optical sensors. Compounds tested include a variety of TBT formulations, antifungal agents, and low-friction silicone-based compounds; time-scales of up to four months were evaluated. The results of these experiments are discussed.

  13. Synthesis and nonlinear optical absorption of novel chalcone derivative compounds

    NASA Astrophysics Data System (ADS)

    Rahulan, K. Mani; Balamurugan, S.; Meena, K. S.; Yeap, G.-Y.; Kanakam, Charles C.

    2014-03-01

    3-(4-(dimethylamino)phenyl)-1-(4-(4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl)phenyl)prop-2-en-1-one was synthesized and its third order nonlinear optical properties have been investigated using a z-scan technique with nanosecond laser pulses at 532 nm. The nonlinear absorption behavior of the compound in chloroform presents a distinct difference at different laser intensity. Interestingly, the compound showed a switchover from saturable absorption (SA) to reverse saturable absorption (RSA) with the increase of excitation intensity. Our studies suggest that compound could be used as a potential candidate for optical device applications such as optical limiters.

  14. Complexes of carboxyl-containing polymer and monosubstituted bipyridinium salts

    NASA Astrophysics Data System (ADS)

    Merekalova, N. D.; Bondarenko, G. N.; Krylsky, D. W.; Zakirov, M. I.; Talroze, R. V.

    2013-09-01

    Semi-empirical PM3 method for the quantum calculations of molecular electronic structure based on NDDO integral approximation is used to investigate the complex formation of monosubstituted 4,4‧-bipyridinium salts BpyR (Hal) containing a halide anion interacting with the quaternary nitrogen atom and carboxylic group of the two-units construct. Significant effect of the BpyR (Hal) electronic structure is unveiled that contributes in two different structures of these salts, namely, partial charge transfer complex and ion pair structure, both having stable energy minima. We demonstrate that (i) the structure of the N-substituent modulates the energy and electronic characteristics of monosubstituted salts BpyR with chlorine and bromine anions and (ii) the coulomb interactions between quaternary N-atom, halogen anion, and the proton of carboxylic group stimulate the transformation of the charge transfer complex into the ion pair structure. Results of calculations are compared with the experimental FTIR spectra of blends of BpyR(Hal) with Eudragit copolymer.

  15. Structures and chiroptical properties of the BINAS-monosubstituted Au38(SCH3)24 cluster

    NASA Astrophysics Data System (ADS)

    Molina, Bertha; Sánchez-Castillo, Ariadna; Knoppe, Stefan; Garzón, Ignacio L.; Bürgi, Thomas; Tlahuice-Flores, Alfredo

    2013-10-01

    The structure and optical properties of a set of R-1,1'-binaphthyl-2,2'-dithiol (R-BINAS) monosubstituted A-Au38(SCH3)24 clusters are studied by means of time dependent density functional theory (TD-DFT). While it was proposed earlier that BINAS selectively binds to monomer motifs (SR-Au-SR) covering the Au23 core, our calculations suggest a binding mode that bridges two dimer (SR-Au-SR-Au-RS) motifs. The more stable isomers show a negligible distortion induced by BINAS adsorption on the Au38(SCH3)24 cluster which is reflected by similar optical and Circular Dichroism (CD) spectra to those found for the parent cluster. The results furthermore show that BINAS adsorption does not enhance the CD signals of the Au38(SCH3)24 cluster.The structure and optical properties of a set of R-1,1'-binaphthyl-2,2'-dithiol (R-BINAS) monosubstituted A-Au38(SCH3)24 clusters are studied by means of time dependent density functional theory (TD-DFT). While it was proposed earlier that BINAS selectively binds to monomer motifs (SR-Au-SR) covering the Au23 core, our calculations suggest a binding mode that bridges two dimer (SR-Au-SR-Au-RS) motifs. The more stable isomers show a negligible distortion induced by BINAS adsorption on the Au38(SCH3)24 cluster which is reflected by similar optical and Circular Dichroism (CD) spectra to those found for the parent cluster. The results furthermore show that BINAS adsorption does not enhance the CD signals of the Au38(SCH3)24 cluster. Electronic supplementary information (ESI) available: Comparison of calculated and experimental optical absorption and CD spectra of the A-38 enantiomer; bond distribution of the A-38 enantiomer, and four studied regioisomers; tables with the excitation energies, oscillator strengths and weights of the electronic transitions; xyz relaxed coordinates of studied regioisomers, frontier orbitals of the relaxed structures. See DOI: 10.1039/c3nr03403h

  16. PPL catalyzed four-component PASE synthesis of 5-monosubstituted barbiturates: Structure and pharmacological properties.

    PubMed

    Bihani, Manisha; Bora, Pranjal P; Verma, Alakesh K; Baruah, Reshita; Boruah, Hari Prasanna Deka; Bez, Ghanashyam

    2015-12-15

    Enzymatic four-component reactions are very rare although three-component enzymatic promiscuous reactions are widely reported. Herein, we report an efficient PASE protocol for the synthesis of potentially lipophilic zwitterionic 5-monosubstituted barbiturates by four component reaction of mixture of ethyl acetoacetate, hydrazine hydrate, aldehyde and barbituric acid in ethanol at room temperature. Seven different lipases were screened for their promiscuous activity towards the synthesis of 5-monosubstituted barbiturates and the lipase from porcine pancreas (PPL) found to give optimum efficiency. The zwitterionic 5-monosubstituted barbiturates with pyrazolyl ring showed promising pharmacological activity upon screening for antibacterial and apoptotic properties. PMID:26546212

  17. Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives - their stability, complexation ability in solution or when deposited on solid anionic surface.

    PubMed

    Popr, Martin; Filippov, Sergey K; Matushkin, Nikolai; Dian, Juraj; Jindřich, Jindřich

    2015-01-01

    The thermal stability of the monosubstituted cationic cyclodextrin (CD) derivatives PEMEDA-β-CD and PEMPDA-β-CD, which differ in their substituent linker length (ethylene and propylene, respectively), was studied via (1)H NMR experiments. PEMPDA-β-CD exhibited higher resistance towards the Hofmann degradation and was chosen as a more suitable host molecule for further studies. Inclusion properties of PEMPDA-β-CD in solution with a series of simple aromatic guests (salicylic acid, p-methoxyphenol and p-nitroaniline) were determined by isothermal titration calorimetry (ITC) and compared to the native β-CD. Permanently charged cationic CD derivatives were successfully deposited on the anionic solid surface of polymeric Nafion(®) 117 membrane via electrostatic interactions. Deposition kinetics and coverage of the surface were determined by ELSD. Finally, the ability of the CD derivatives bound to the solid surface to encapsulate aromatic compounds from aqueous solution was measured by UV-vis spectroscopy. The obtained results are promising for future industrial applications of the monosubstituted β-CD derivatives, because the preparation of cationic CD derivatives is applicable in large scale, without the need of chromatographic purification. Their ionic deposition on a solid surface is simple, yet robust and a straightforward process as well. PMID:25815069

  18. Salicylanilide N-monosubstituted carbamates: Synthesis and in vitro antimicrobial activity.

    PubMed

    Krátký, Martin; Vinšová, Jarmila

    2016-03-15

    The research of innovative antimicrobial agents represents a cutting edge topic. Hence, we synthesized and characterised novel salicylanilide N-monosubstituted carbamates. Twenty compounds were evaluated in vitro against eight bacterial strains and eight fungal species. The lowest minimum inhibitory concentrations (MICs) were found to be ⩽0.49μM. Genus Staphylococcus, including methicillin-resistant Staphylococcus aureus, and fungus Trichophyton mentagrophytes showed uniformly the highest rate of susceptibility, whilst Gram-negative bacteria and most of the fungi were less susceptible. A wide range of carbamates provided comparable or superior in vitro antimicrobial activity in comparison to established drugs. Interestingly, extended-spectrum β-lactamase producing strain of Klebsiella pneumoniae was inhibited with MICs starting from 31.25μM. With respect to Staphylococci, 2-[(4-bromophenyl)carbamoyl]-4-chlorophenyl phenylcarbamate exhibited the lowest MIC values (⩽0.98μM). 2-[(4-Bromophenyl)carbamoyl]-4-chlorophenyl benzylcarbamate showed the widest spectrum of antifungal action. The results indicate that some salicylanilide carbamates can be considered to be promising candidates for future investigation. PMID:26879856

  19. The structure-activity relationship in herbicidal monosubstituted sulfonylureas

    SciTech Connect

    Li, Zheng-Ming; Ma, Yi; Guddat, Luke; Cheng, Pei-Quan; Wang, Jian-Guo; Pang, Siew S; Dong, Yu-Hui; Lai, Cheng-Ming; Wang, Ling-Xiu; Jia, Guo-Feng; Li, Yong-Hong; Wang, Su-Hua; Liu, Jie; Zhao, Wei-Guang; Wang, Bao-Lei

    2012-05-24

    The herbicide sulfonylurea (SU) belongs to one of the most important class of herbicides worldwide. It is well known for its ecofriendly, extreme low toxicity towards mammals and ultralow dosage application. The original inventor, G Levitt, set out structure-activity relationship (SAR) guidelines for SU structural design to attain superhigh bioactivity. A new approach to SU molecular design has been developed. After the analysis of scores of SU products by X-ray diffraction methodology and after greenhouse herbicidal screening of 900 novel SU structures synthesized in the authors laboratory, it was found that several SU structures containing a monosubstituted pyrimidine moiety retain excellent herbicidal characteristics, which has led to partial revision of the Levitt guidelines. Among the novel SU molecules, monosulfuron and monosulfuron-ester have been developed into two new herbicides that have been officially approved for field application and applied in millet and wheat fields in China. A systematic structural study of the new substrate-target complex and the relative mode of action in comparison with conventional SU has been carried out. A new mode of action has been postulated.

  20. Volatile Organic Compound Optical Fiber Sensors: A Review

    PubMed Central

    Elosua, Cesar; Matias, Ignacio R.; Bariain, Candido; Arregui, Francisco J.

    2006-01-01

    Volatile organic compound (VOC) detection is a topic of growing interest with applications in diverse fields, ranging from environmental uses to the food or chemical industries. Optical fiber VOC sensors offering new and interesting properties which overcame some of the inconveniences found on traditional gas sensors appeared over two decades ago. Thanks to its minimum invasive nature and the advantages that optical fiber offers such as light weight, passive nature, low attenuation and the possibility of multiplexing, among others, these sensors are a real alternative to electronic ones in electrically noisy environments where electronic sensors cannot operate correctly. In the present work, a classification of these devices has been made according to the sensing mechanism and taking also into account the sensing materials or the different methods of fabrication. In addition, some solutions already implemented for the detection of VOCs using optical fiber sensors will be described with detail.

  1. Nonlinear optical properties and optical limiting measurements of graphene oxide - Ag@TiO2 compounds

    NASA Astrophysics Data System (ADS)

    Ebrahimi, M.; Zakery, A.; Karimipour, M.; Molaei, M.

    2016-07-01

    In this work Graphene Oxide (GO), Ag@TiO2 core-shells and GO-Ag@TiO2 compounds were prepared and experimentally verified. Using a low power laser diode with 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index and nonlinear absorption were determined by the Z-scan technique. It was observed that the nonlinear absorption of GO-Ag@TiO2 mixture was higher than pure GO. The optical limiting effect of these samples was also investigated using the 2nd harmonics of a pulsed Nd-YAG laser at 532 nm. Our results showed that the sole Ag@TiO2 didn't show any appreciable optical limiting effect, however after just mixing with graphene oxide the threshold of optical limiting was increased and the compound showed an enhancement of optical limiting behavior compared to GO itself. The presented results are discussed and compared with other literature reports.

  2. Crystal stability and optical properties of organic chain compounds

    NASA Astrophysics Data System (ADS)

    Zupanovic, P.; Bjelis, A.; Barisic, S.

    1999-01-01

    The solution to the long-standing problem of the cohesion of organic chain compounds is proposed. We consider the tight-binding dielectric matrix with two electronic bands per chain, determine the corresponding hybridized collective modes, and show that three among them are considerably softened due to strong dipole-dipole and monopole-dipole interactions. By this we explain the unusual low-frequency optical activity of TTF-TCNQ, including the observed 10 meV anomaly. The softening of the modes also explains the cohesion of the mixed-stack lattice, the fractional charge transfer almost independent of the material, and the formation of the charged sheets in some compounds.

  3. Spin-Exchange Optical Pumping of Solid Alkali Compounds

    NASA Astrophysics Data System (ADS)

    Patton, Brian; Ishikawa, Kiyoshi; Jau, Yuan-Yu; Happer, William

    2007-06-01

    We demonstrate enhancement of the ^133Cs nuclear polarization in a film of cesium hydride which has been placed in contact with an optically pumped cesium vapor. The maximum observed polarization at 9.4 T and 137 ^oC is roughly 4 times the equilibrium polarization, but higher magnetizations are possible at lower magnetic fields. In an attempt to determine the mechanism of spin transfer from the alkali vapor to the solid, we have performed this experiment at intermediate magnetic fields (1-2 tesla) while pumping different optical transitions in the vapor. We will discuss the predicted spin current to the CsH layer in this regime of partial hyperfine decoupling and propose new methods for generating even higher polarizations in the solid. Potential applications of this technique will be mentioned as well as its extension to other compounds.

  4. Caged compounds for multichromic optical interrogation of neural systems

    PubMed Central

    Amatrudo, Joseph M.; Olson, Jeremy P.; Agarwal, Hitesh K.; Ellis-Davies, Graham C.R.

    2014-01-01

    Caged compounds have widely used by neurophysiologists to study many aspects of cellular signaling in glia and neurons. Biologically inert before irradiation, they can be loaded into cells via patch pipette or topically applied in situ to a defined concentration, photolysis releases the caged compound in a very rapid and spatially defined way. Since caged compounds are exogenous optical probes, they include not only natural products such neurotransmitters, calcium and IP3, but non-natural products such as fluorophores, drugs and antibodies. In this Technical Spotlight we provide a short introduction to the uncaging technique by discussing the nitroaromatic caging chromophores most widely used in such experiments (e.g. CNB1, DMNB, MNI and CDNI). We show that recently developed caging chromophores (RuBi and DEAC450) that are photolyzed with blue light (ca. 430–480 nm range) can be combined with traditional nitroaromatic caged compounds to enable two-color optical probing of neuronal function. For example, one-photon uncaging of either RuBi-GABA or DEAC450-GABA with a 473-nm laser is facile, and can block non-linear currents (dendritic spikes or action potentials) evoked by two-photon uncaging of CDNI-Glu at 720 nm. We also show that two-photon uncaging of DEAC450-Glu and CDNI-GABA at 900 and 720 nm, respectively, can be used to fire and block action potentials. Our experiments illustrate that recently developed chromophores have taken uncaging out of the “monochrome era”, in which it has existed since 1978, so as to enable multichromic interrogation of neuronal function with single synapse precision. PMID:25471355

  5. 40 CFR 721.9700 - Monosubstituted alkoxy-amino-tra-zines (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...)(1)(viii), (g)(2)(i) and (g)(2)(v), (g)(4)(xi), and (g)(5). The provisions of § 721.72(d) requiring.... Requirements as specified in § 721.63 (a)(1), (a)(3), (a)(4), (a)(5)(iii) through (a)(5)(vii), and (a)(6)(i... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Monosubstituted...

  6. 40 CFR 721.9700 - Monosubstituted alkoxy-amino-tra-zines (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...)(1)(viii), (g)(2)(i) and (g)(2)(v), (g)(4)(xi), and (g)(5). The provisions of § 721.72(d) requiring.... Requirements as specified in § 721.63 (a)(1), (a)(3), (a)(4), (a)(5)(iii) through (a)(5)(vii), and (a)(6)(i... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Monosubstituted...

  7. Modular Approach to 9-Monosubstituted Fluorene Derivatives Using Mo(V) Reagents.

    PubMed

    Franzmann, Peter; Trosien, Simon; Schubert, Moritz; Waldvogel, Siegfried R

    2016-03-01

    Oxidative coupling using molybdenum(V) reagents provides fast access to highly functionalized 9-monosubstituted fluorenes. This synthetic approach is highly modular, is high yielding, and tolerates a variety of labile moieties, e.g. amides or iodo groups. The established protocol leads to promising precursors for pharmacologically important analogues of melatonin. PMID:26913835

  8. Optical biosensors for bacteria detection by a peptidomimetic antimicrobial compound.

    PubMed

    Tenenbaum, Elena; Segal, Ester

    2015-11-21

    In this work we present a label-free optical biosensor for rapid bacteria detection using a novel peptide-mimetic compound, as the recognition element. The biosensor design is based on an oxidized porous silicon (PSiO2) nanostructure used as the optical transducer, functionalized with the sequence K-[C12K]7 (referred to as K-7α12), which is a synthetic antimicrobial peptide. This compound is a member of a family of oligomers of acylated lysines (OAKs), mimicking the hydrophobicity and charge of natural antimicrobial peptides. The OAK is tethered to the PSiO2 film and the changes in the reflectivity spectrum are monitored upon exposure to Escherichia coli (E. coli) bacterial suspensions and their lysates. We show that capture of bacterial cell fragments induces predictable changes in the reflectivity spectrum, proportional to E. coli concentrations, thereby enabling rapid, sensitive and reproducible detection of E. coli at concentrations as low as 10(3) cells per mL. While for intact bacterial cells, the K-7α12-tethered PSiO2 shows a poor capturing ability, resulting in an insignificant optical response. The biosensor performance is also studied upon exposure to model Gram positive and negative bacterial lysates, suggesting preferential capture of E. coli cell fragments in the presented scheme. These OAK-based biosensors offer significant advantages in comparison with conventional antibody-based assays, in terms of their simple and cost-effective production, while providing numerous possible sequence combinations for designing new detection schemes. PMID:26456237

  9. Properties of cationic monosubstituted tetraalkylammonium cyclodextrin derivatives – their stability, complexation ability in solution or when deposited on solid anionic surface

    PubMed Central

    Popr, Martin; Filippov, Sergey K; Matushkin, Nikolai; Dian, Juraj

    2015-01-01

    Summary The thermal stability of the monosubstituted cationic cyclodextrin (CD) derivatives PEMEDA-β-CD and PEMPDA-β-CD, which differ in their substituent linker length (ethylene and propylene, respectively), was studied via 1H NMR experiments. PEMPDA-β-CD exhibited higher resistance towards the Hofmann degradation and was chosen as a more suitable host molecule for further studies. Inclusion properties of PEMPDA-β-CD in solution with a series of simple aromatic guests (salicylic acid, p-methoxyphenol and p-nitroaniline) were determined by isothermal titration calorimetry (ITC) and compared to the native β-CD. Permanently charged cationic CD derivatives were successfully deposited on the anionic solid surface of polymeric Nafion® 117 membrane via electrostatic interactions. Deposition kinetics and coverage of the surface were determined by ELSD. Finally, the ability of the CD derivatives bound to the solid surface to encapsulate aromatic compounds from aqueous solution was measured by UV–vis spectroscopy. The obtained results are promising for future industrial applications of the monosubstituted β-CD derivatives, because the preparation of cationic CD derivatives is applicable in large scale, without the need of chromatographic purification. Their ionic deposition on a solid surface is simple, yet robust and a straightforward process as well. PMID:25815069

  10. Optical amplification and stability of spiroquaterphenyl compounds and blends

    NASA Astrophysics Data System (ADS)

    Fuhrmann-Lieker, T.; Lambrecht, J.; Hoinka, N.; Kiurski, M.; Wiske, A.; Hagelstein, G.; Yurttagül, Y.; Abdel-Awwad, M.; Wilke, H.; Messow, F.; Hillmer, H.; Salbeck, J.

    2015-02-01

    In this contribution, we present a systematic investigation on a series of spiroquaterphenyl compounds optimised for solid state lasing in the near ultraviolet (UV). Amplified spontaneous emission (ASE) thresholds in the order of 1 μJ/cm^2 are obtained in neat (undiluted) films and blends, with emission peaks at 390±1 nm for unsubstituted and meta-substituted quaterphenyls and 400±4 nm for para-ether substituted quaterphenyls. Mixing with a transparent matrix retains a low threshold, shifts the emission to lower wavelengths and allows a better access to modes having their intensity maximum deeper in the film. Chemical design and blending allow an independent tuning of optical and processing properties such as the glass transition.

  11. Spin-Exchange Optical Pumping of Solid Alkali Compounds

    NASA Astrophysics Data System (ADS)

    Patton, Brian; Ishikawa, Kiyoshi; Jau, Yuan-Yu; Happer, William

    2007-03-01

    Spin-exchange optical pumping of noble gases has been used for many years to create highly non-equilibrium spin populations, with applications ranging from fundamental physics[1] to medical imaging[2]. In this procedure, angular momentum is transferred from circularly-polarized laser light to the electron spins of an alkali vapor and ultimately to the nuclei of a gas such as ^3He or ^129Xe. Here we show experimentally that a similar process can be used to polarize the nuclei of a solid film of cesium hydride which coats the walls of an optical pumping cell. We present nuclear magnetic resonance (NMR) data which demonstrate that the nuclear polarization of ^133Cs in CsH can be enhanced above the Boltzmann limit in a 9.4-Tesla magnetic field. Possible spin-exchange mechanisms will be discussed, as well as the extension of this technique to other compounds. [1] T. W. Kornack, R. K. Ghosh, and M. V. Romalis, Phys. Rev. Lett. 95, 23080 (2005). [2] M. S. Conradi, D. A. Yablonskiy, et al., Acad. Radiol. 12, 1406 (2005).

  12. Low Scatter Edge Blackening Compounds For Refractive Optical Elements

    NASA Astrophysics Data System (ADS)

    Lewis, Isabella T.; Telkamp, Arthur R.; Ledebuhr, Arno G.

    1990-01-01

    Perkin-Elmer's Applied Optics Operation recently delivered several prototype wide-field-of-view (WFOV), F/2.8, 250 mm efl, near diffraction limited, concentric refractive lenses to Lawrence Livermore National Laboratory (LLNL). In these lenses, special attention was paid to reducing stray light to allow viewing of very dim objects. Because of the very large FOV, the use of a long baffle to eliminate direct illumination of lens edges was not practical. With the existing relatively short baffle design, one-bounce stray light paths off the element edges are possible. The scattering off the inside edges thus had to be kept to an absolute minimum. While common means for blackening the edges of optical elements are easy to apply and quite cost effective for normal lens assemblies, their blackening effect is limited by the Fresnel reflection due to the index of refraction mismatch at the glass boundary. At high angles of incidence, total internal reflection (TIR) might occur ruining the effect of the blackening process. An index-matched absorbing medium applied to the edges of such elements is the most effective approach for reducing the amount of undesired light reflected or scattered off these edges. The presence of such a medium provides an extended path outside the glass boundary in which an absorptive non-scattering dye can be used to eliminate light that might otherwise have propagated to the focal plane. Perkin-Elmer and LLNL undertook a program to develop epoxy-based dye carrier compounds with refractive indices corresponding to the glass types used in the WFOV lens. This program involved the measuring of the refractive index of a number of epoxy compounds and catalysts, the experimental combination of epoxies to match our glass indices, and the identification of a suitable non-scattering absorptive dye. Measurements on these blacks showed Bidirectional Reflectance Distribution Functions (BRDFs) between 1.4 and 3.1 orders of magnitude lower than Perkin

  13. Synthesis, characterisation, electrical and optical properties of copper borate compounds

    SciTech Connect

    Kipcak, Azmi Seyhun; Senberber, Fatma Tugce; Aydin Yuksel, Sureyya; Derun, Emek Moroydor; Piskin, Sabriye

    2015-10-15

    Highlights: • Cu(BO{sub 2}){sub 2} was synthesized at the form of with pdf number of “00-001-0472”. • Particle sizes were found between 162.72 and 56.44 nm and 195.76 and 75.73 nm at CuSNaH. • Reaction yields were 90.4 ± 0.84, 96.9 ± 0.78 and 78.9 ± 0.76% for CuST, CuSB and CuSNaH. • The resistivity of CuST, CuSB and CuSNaH are 1.10 × 10{sup 7}, 7.02 × 10{sup 6} and 8.62 × 10{sup 5} Ωm. • The optical energy gap was 3.76 eV. - Abstract: The hydrothermal synthesis of copper borate compounds [Cu(BO{sub 2}){sub 2}] was studied, and several parameters were found to affect the synthesis. Raw materials, including CuSO{sub 4}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·5H{sub 2}O, Na{sub 2}B{sub 4}O{sub 7}·10H{sub 2}O, NaOH and H{sub 3}BO{sub 3}, were used. Reaction temperatures and reaction times between 40 °C and 100 °C and 15 and 240 min, respectively, were used. The as-synthesised copper borate was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The yields of the reactions were also calculated. Single-phase, nanoparticulate copper borate compounds (Cu(BO{sub 2}){sub 2}) possessing high XRD crystal scores were obtained; the reactions used to obtain these materials were highly efficient. Electrical resistivity and optical absorbance measurements were carried out on the compounds obtained from the highest yielding reactions. The results of this study showed that even using a reaction time of 15 min, copper borate formation was successfully achieved.

  14. Optical characterization of gaps in directly bonded Si compound optics using infrared spectroscopy.

    PubMed

    Gully-Santiago, Michael; Jaffe, Daniel T; White, Victor

    2015-12-01

    Silicon direct bonding offers flexibility in the design and development of Si optics by allowing manufacturers to combine subcomponents with a potentially lossless and mechanically stable interface. The bonding process presents challenges in meeting the requirements for optical performance because air gaps at the Si interface cause large Fresnel reflections. Even small (35 nm) gaps reduce transmission through a direct bonded Si compound optic by 4% at λ=1.25  μm at normal incidence. We describe a bond inspection method that makes use of precision slit spectroscopy to detect and measure gaps as small as 14 nm. Our method compares low-finesse Fabry-Perot models to high-precision measurements of transmission as a function of wavelength. We demonstrate the validity of the approach by measuring bond gaps of known depths produced by microlithography. PMID:26836675

  15. Femtosecond Laser Microfabrication of an Integrated Device for Optical Release and Sensing of Bioactive Compounds

    PubMed Central

    Ghezzi, Diego; Vazquez, Rebeca Martinez; Osellame, Roberto; Valtorta, Flavia; Pedrocchi, Alessandra; Valle, Giuseppe Della; Ramponi, Roberta; Ferrigno, Giancarlo; Cerullo, Giulio

    2008-01-01

    Flash photolysis of caged compounds is one of the most powerful approaches to investigate the dynamic response of living cells. Monolithically integrated devices suitable for optical uncaging are in great demand since they greatly simplify the experiments and allow their automation. Here we demonstrate the fabrication of an integrated bio-photonic device for the optical release of caged compounds. Such a device is fabricated using femtosecond laser micromachining of a glass substrate. More in detail, femtosecond lasers are used both to cut the substrate in order to create a pit for cell growth and to inscribe optical waveguides for spatially selective uncaging of the compounds present in the culture medium. The operation of this monolithic bio-photonic device is tested using both free and caged fluorescent compounds to probe its capability of multipoint release and optical sensing. Application of this device to the study of neuronal network activity can be envisaged.

  16. Fiber Optic Biosensing Probes For Biomedically Important Compounds

    NASA Astrophysics Data System (ADS)

    Arnold, Mark A.

    1988-06-01

    Fiber optic biosensing probes for several bioanalytes of clinical and biomedical importance are described. The development of biosensors based on immobilization of a deaminating enzyme at the tip of a fiber optic ammonia sensor is illustrated with a biosensing probe for urea. In addition, biosensors based on the direct fluorometric detection of reduced nicotinamide adenine dinucleotide (NADH) at the tip of an optical fiber device are presented. Probes for lactate and pyruvate illustrate this concept. Finally, preliminary results from an investigation to prepare NADH sensing probes based on immobilized bacterial luciferase are given.

  17. Liquid chromatography analysis of monosubstituted sulfobutyl ether-beta-cyclodextrin isomers on porous graphitic carbon.

    PubMed

    Jacquet, Romain; Pennanec, Rodolphe; Elfakir, Claire; Lafosse, Michel

    2004-10-01

    The retention behaviour of the three positional isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was investigated on a porous graphitic carbon (PGC) column. The influence of the mobile phase composition (nature and concentration of organic and electronic modifiers) was studied as well as the effect of column temperature. These hydrophilic and anionic analytes were highly retained on the PGC stationary phase compared to octadecyl bonded phases. The retention is mainly governed by a reversed-phase mechanism with electronic interaction playing a secondary role. An increase in solute retention and efficiency with temperature was observed. Successful isocratic separation with satisfactory baseline resolution of the three isomers of monosubstituted sulfobutyl ether-beta-cyclodextrin was achieved at 75 degrees C on a Hypercarb column by using ammonium acetate as electronic modifier in water-acetonitrile (83:17). The chromatographic methodology developed can be easily used for relative quantification of each isomer within a mixture and can be applied for semi-preparative purification of each one. The evaporative light scattering detector allows the detection of these non UV-visible absorbing molecules. PMID:15537080

  18. Exciting fluorescence compounds on an optical fiber's side surface with a liquid core waveguide.

    PubMed

    Ray, Jason C; Almas, Muhammad S; Tao, Shiquan

    2016-01-01

    A new fiber optic fluorescence spectroscopic method using a liquid core waveguide (LCW) as an excitation element has been developed for detecting a fluorescence compound absorbed on an optical fiber's surface. A laser light beam was coupled into a multimode optical fiber. The distal end of the fiber was inserted into an LCW. The diverging light emerging from the fiber's end was collected and guided within the LCW. A tapered optical fiber was inserted into the LCW from the other side. Laser light traveling in the LCW evenly illuminates the tapered fiber surface and excites fluorescence molecules absorbed on the tapered fiber's surface. Fluorescence light emitted from the tapered fiber surface was collected with the fiber itself and delivered through the fiber to an optical fiber compatible spectrometer for detection. This new technique provides an efficient way for evenly exciting fluorescence compounds absorbed on an optical fiber's surface. PMID:26696168

  19. Depth profiling of photothermal compound concentrations using phase sensitive optical coherence tomography

    PubMed Central

    Guan, Guangying; Reif, Roberto; Huang, Zhihong; Wang, Ruikang K.

    2011-01-01

    A model that describes the concentration of photothermal (light-to-heat converters) compounds as a function of depth in a turbid medium is developed. The system consists of a pump laser (808 nm modulated at 400 Hz), which heats a photothermal compound, and a phase sensitive spectral domain optical coherence tomography system, which detects the changes in the optical path length of the sample induced by the temperature increase. The model is theoretically derived and the coefficients are empirically determined using solid homogeneous gel phantoms. The model is validated by reconstructing the concentration of a photothermal compound in thick single and double layer solid phantoms. PMID:22191920

  20. Optically enhanced oxidation of III-V compound semiconductors

    NASA Astrophysics Data System (ADS)

    Fukuda, Mitsuo; Takahei, Kenichiro

    1985-01-01

    Oxidation of III-V compound semiconductor (110) cleaved surfaces under light irradiation is studied. The light irradiation enhanced the reaction rate of oxidation but the relationship between oxide growth and oxidation time under logarithmic law scarcely changed within this experimental range. The oxidation trend observed under light irradiation is similar to that of thermal oxidation for GaP, GaAs, InP, InAs, InGaAs, and InGaAsP. Semiconductors having As as the V element tend to be easily oxidized, while those of the above mentioned six kinds of materials having Ga as the III element are quickly oxidized in their initial stage. Ternary and quaternary compound semiconductors have less tendency to be oxidized compared to their constituent binary materials. off

  1. Topological band order, structural, electronic and optical properties of XPdBi (X = Lu, Sc) compounds

    NASA Astrophysics Data System (ADS)

    Narimani, M.; Nourbakhsh, Z.

    2016-05-01

    In this paper, the structural, electronic and optical properties of LuPdBi and ScPdBi compounds are investigated using the density functional theory by WIEN2K package within the generalized gradient approximation, local density approximation, Engel-Vosco generalized gradient approximations and modified Becke-Johnson potential approaches. The topological phases and band orders of these compounds are studied. The effect of pressure on band inversion strength, electron density of states and the linear coefficient of the electronic specific heat of these compounds is investigated. Furthermore, the effect of pressure on real and imaginary parts of dielectric function, absorption and reflectivity coefficients of these compounds is studied.

  2. Comparative toxicity and structure-activity in Chlorella and Tetrahymena: Monosubstituted phenols

    SciTech Connect

    Jaworska, J.S.; Schultz, T.W. )

    1991-07-01

    The relative toxicity of selected monosubstituted phenols has been assessed by Kramer and Truemper in the Chlorella vulgaris assay. The authors examined population growth inhibition of this simple green algae under short-term static conditions for 33 derivatives. However, efforts to develop a strong predictive quantitative structure-activity relationship (QSAR) met with limited success because they modeled across modes of toxic action or segregated derivatives such as positional isomers (i.e., ortho-, meta-, para-). In an effort to further their understanding of the relationships of ecotoxic effects of phenols, the authors have evaluated the same derivatives reported by Kramer and Truemper in the Tetrahymena pyriformis population growth assay, compared the responses in both systems and developed QSARs for the Chlorella vulgaris data based on mechanisms of action.

  3. Optical Evaluation of an As-Manufactured Compound Secondary Concentrator

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; Skowronski, Timothy J.; Miles, Barry J.

    1999-01-01

    Secondary concentrators are needed in solar thermal propulsion to further concentrate the energy collected by large lightweight primary concentrators. Although the physics of secondary concentrators has been worked out in detail and the manufacturing has been successfully completed for a ground demonstration, there is a need to quantify the specific performance of as-manufactured concentrators. This paper summarizes the properties of a secondary concentrator manufactured for the Integrated Solar Upper Stage engine ground demonstration in 1997 and presents data obtained from the optic that describe the performance of the as-manufactured component.

  4. Optical properties of NbCl5 and ZnMg intercalated graphite compounds

    NASA Astrophysics Data System (ADS)

    Jung, Eilho; Lee, Seokbae; Roh, Seulki; Meng, Xiuqing; Tongay, Sefaattin; Kang, Jihoon; Park, Tuson; Hwang, Jungseek

    2014-12-01

    We studied NbCl5 and ZnMg alloy intercalated graphite compounds using an optical spectroscopy technique. These intercalated metallic graphite samples were quite challenging to obtain optical reflectance spectra since they were not flat and quite thin. By using both a new method and an in situ gold evaporation technique we were able to obtain reliable reflectance spectra of our samples in the far and mid infrared range (80-7000 cm-1). We extracted the optical constants including the optical conductivity and the dielectric function from the measured reflectance spectra using a Kramers-Kronig analysis. We also extracted the dc conductivity and the plasma frequencies from the optical conductivity and dielectric functions. NbCl5 intercalated graphite samples show similar optical conductivity spectra as bare highly oriented pyrolytic graphite even though there are some differences in detail. ZnMg intercalated samples show significantly different optical conductivity spectra from the bare graphite. Optical spectroscopy is one of the most reliable experimental techniques to obtain the electronic band structures of materials. The obtained optical conductivities support the recent theoretically calculated electronic band structures of NbCl5 and ZnMg intercalated graphite compounds. Our results also provide important information of electronic structures and charge carrier properties of these two new intercalated materials for applications.

  5. Noncrystalline Condensation of Densely Dissolved Optically Nonlinear Organic Compound in Polymer Matrices

    NASA Astrophysics Data System (ADS)

    Hiraga, Takashi; Tanaka, Norio; Hayamizu, Kikuko; Mito, Akihiro; Takarada, Shigeru; Yamasaki, Yuuichi; Nakamura, Michie; Hoshino, Nobuo; Moriya, Tetsuo

    1993-04-01

    Optical properties and condensed states of the densely dissolved optically nonlinear organic compound in polymer matrices were investigated by means of optical measurements, structural analysis and pressure tuning spectroscopy. In the investigation of the absorption peak wavelength, 2-methyl-4-nitroaniline (MNA) in poly(methyl methacrylate) (PMMA) exhibited characteristics intermediate between the crystal and the MNA dissolved in solvents, i.e., noncrystalline condensation. This result was consistent with those of X-ray diffraction analysis, second- and third-harmonics generation, IR absorption and 13C-NMR spectroscopies. It has also been revealed that such a system provides the most suitable measuring method of the third optical nonlinear constant for a variety of compounds.

  6. Optical properties across the insulator to metal transitions in vanadium oxide compounds.

    PubMed

    Perucchi, A; Baldassarre, L; Postorino, P; Lupi, S

    2009-08-12

    We review the optical properties of three vanadium oxide compounds V(2)O(3), VO(2) and V(3)O(5), belonging to the so-called Magnéli phase. Their electrodynamics across a metal to insulator transition is investigated as a function of both temperature and pressure. We analyse thoroughly the optical results, with a special emphasis on the infrared spectral weight. This allows us to discuss the nature of the mechanisms driving the phase transitions in the three compounds, pointing out the role of electron-electron and electron-phonon interactions in the various cases. PMID:21693963

  7. Nonlinear optical properties of new organotellurium compounds containing azomethine and azo groups under CW laser illumination

    NASA Astrophysics Data System (ADS)

    Saadon, H. L.; Ali, Basil; Al-Fregi, Adil A.

    2014-06-01

    Two new organotellurium compounds containing azomethine and azo groups, [2-(2-hydroxynaphthylazo)phenyl][2-(2-methoxybenzylideneamino)-5-methylphenyl]tellurium dibromide (P1) and [2-(2-hydroxynaphthylazo)-5-nitrophenyl][2-(2-methoxy benzylideneamino)-5-methyl phenyl]tellurium dibromide (P2) were synthesized and doped in polyvinylprodidone (PVP) matrix. The nonlinear optical (NLO) properties of these compounds and doped polymer were studied using Z-scan technique at 532 nm. The Z-scan results reveal that the sample solutions and films exhibit self-defocusing nonlinearity. The P2/PVP solutions investigated here exhibit good optical power limiting.

  8. Spatial compound imaging for fiber-bundle optic microscopy

    NASA Astrophysics Data System (ADS)

    Cheon, Gyeong Woo; Cha, Jaepyeong; Kang, Jin U.

    2014-02-01

    Coherent fiber bundles with high core density give both flexibility and high resolution to microscopy. Despite of these advantages, fiber bundles inevitably have uncovered region between adjacent cores. The region results in structural artifact known as pixelation effect. Many kinds of image processing techniques have been introduced to remove this pixelation artifact such as frequency domain filter and Gaussian filter. However, these methods fundamentally have limitation because they use the information of adjacent pixels to make up for these uncovered area; therefore, they cannot avoid blurring effect as a result. To overcome this problem, we introduce spatial compound imaging method to overcome this pixelation artifact. The method uses multiple frames taken with small deviation of position. Some parts of these images include information which is devoid of in other images. The total amount of information increase as more images are added up and we can expect the improvement of resolution in the final images. At the same time, the duplicated parts among these images can be averaged to improve SNR ratio. For these improvements, we essentially need sophisticated registration algorithm. The pixelation artifact is troublesome again in registration process because its structural artifacts are strong features shared with whole images. However, we can solve this problem by using reference image and divide the sample images into two parts: effective and ineffective regions. We used effective regions for registration. We used USAF target to evaluate our method and we could get a result that SNR and resolution are both critically increase.

  9. Synthesis of new LC compounds with high optical anisotropy: pentaphenyl derivatives lateral substituted

    NASA Astrophysics Data System (ADS)

    Sasnouski, Genadz; Lapanik, Valery; Dabrowski, Roman; Dziaduszek, Jerzy

    2012-04-01

    A new pentaphenyl liquid crystalline (LC) compounds with 2,3-difluorobenzene moiety exhibiting wide nematic range have been prepared. The key stage is the condensation of the corresponding 3-dimethylaminopropanoyl-4-pentyl benzene hydrochloride with substituted methyl benzyl ketone in the presence of base leading to 3,6-disubstituted cyclohexenones. Methylation with methyl magnesium iodide followed by oxidative aromatization gives three-ring bromides, which are used in the Suzuki cross-coupling reaction. Pentaphenyl LC compounds possessing lateral methyl group have moderate melting points, improved solubility, and miscibility with another LC components. The new compounds could be useful in LC compositions with the high optical anisotropy.

  10. Fiber-optic surface-enhanced Raman system for field screening of hazardous compounds

    SciTech Connect

    Ferrell, T.L.; Goudonnet, J.P.; Arakawa, E.T.; Reddick, R.C.; Gammage, R.B.; Haas, J.W.; James, D.R.; Wachter, E.A.

    1988-01-01

    Surface-enhanced Raman scattering permits identification of compounds adsorbed onto a metal microbase that is microlithographically produced with submicron resolution. Less than one percent of a monolayer of a Raman Active target compound offers a high signal-to-noise ratio. By depositing the microbase on the exterior of a fiber optic cable, convenient field screening or monitoring is permitted. By using highly effective microbases, it is possible to reduce laser power requirements sufficiently to allow an economical, but complete, system to be housed in a suitcase. We shall present details of SERS system of this type and shall show data on samples of interest in the screening of hazardous compounds.

  11. Ab initio study of the structural, electronic and optical properties of ZnTe compound

    SciTech Connect

    Bahloul, B.; Deghfel, B.; Amirouche, L.; Bounab, S.; Bentabet, A.; Bouhadda, Y.; Fenineche, N.

    2015-03-30

    Structural, electronic and optical properties of ZnTe compound were calculated using Density Functional Theory (DFT) based on the pseudopotentials and planewaves (PP-PW) method as implemented in the ABINIT computer code, where the exchange–correlation functional is approximated using the local density approximation (LDA) and the generalized gradient approximation (GGA). The obtained results from either LDA or GGa calculation for lattice parameter, energy band gap and optical parameters, such as the fundamental absorption edge, the peaks observed in the imaginary part of the dielectric function, the macroscopic dielectric constants and the optical dielectric constant, are compared with the available theoretical results and experimental data.

  12. Kinetic Resolution of Racemic and Branched Monosubstituted Allylic Acetates by a Ruthenium-Catalyzed Regioselective Allylic Etherification.

    PubMed

    Shinozawa, Toru; Terasaki, Shou; Mizuno, Shota; Kawatsura, Motoi

    2016-07-01

    We demonstrated the kinetic resolution of racemic and branched monosubstituted allylic acetates by a ruthenium-catalyzed regioselective allylic etherification. The reaction was effectively catalyzed by the chiral ruthenium catalyst, which was generated by [RuCl2(p-cymene)]2 and (S,S)-iPr-pybox and a catalytic amount of TFA, and both the allylic etherification product and recovered allylic acetate were obtained as an enantiomerically enriched form with up to a 103 s value. PMID:27276556

  13. Recessive optic atrophy, sensorimotor neuropathy and cataract associated with novel compound heterozygous mutations in OPA1.

    PubMed

    Lee, Jinho; Jung, Sung-Chul; Hong, Young Bin; Yoo, Jeong Hyun; Koo, Heasoo; Lee, Ja Hyun; Hong, Hyun Dae; Kim, Sang-Beom; Chung, Ki Wha; Choi, Byung-Ok

    2016-07-01

    Mutations in the optic atrophy 1 gene (OPA1) are associated with autosomal dominant optic atrophy and 20% of patients demonstrate extra-ocular manifestations. In addition to these autosomal dominant cases, only a few syndromic cases have been reported thus far with compound heterozygous OPA1 mutations, suggestive of either recessive or semi‑dominant patterns of inheritance. The majority of these patients were diagnosed with Behr syndrome, characterized by optic atrophy, ataxia and peripheral neuropathy. The present study describes a 10-year-old boy with Behr syndrome presenting with early‑onset severe optic atrophy, sensorimotor neuropathy, ataxia and congenital cataracts. He had optic atrophy and was declared legally blind at six years old. Electrophysiological, radiological, and histopathological findings were compatible with axonal sensorimotor polyneuropathy. At birth, he presented with a congenital cataract, which has not been previously described in patients with OPA1 mutations. Whole exome sequencing indicated a pair of novel compound heterozygous mutations: p.L620fs*13 (c.1857‑1858delinsT) and p.R905Q (c.G2714A). Neither mutation was observed in controls (n=300), and thus, they were predicted to be pathogenic by multiple in silico analyses. The mutation sites were highly conserved throughout different vertebrate species. The patients parents did not have any ophthalmic or neurologic symptoms and the results of electrophysiological studies were normal, suggestive of an autosomal recessive pattern of inheritance. The present study identified novel compound heterozygous OPA1 mutations in a patient with recessive optic atrophy, sensorimotor neuropathy and congenital cataracts, indicating an expansion of the clinical spectrum of pathologies associated with OPA1 mutations. Thus, OPA1 gene screening is advisable in the workup of patients with recessive optic atrophy, particularly with Behr syndrome and cataracts. PMID:27150940

  14. Recessive optic atrophy, sensorimotor neuropathy and cataract associated with novel compound heterozygous mutations in OPA1

    PubMed Central

    LEE, JINHO; JUNG, SUNG-CHUL; HONG, YOUNG BIN; YOO, JEONG HYUN; KOO, HEASOO; LEE, JA HYUN; HONG, HYUN DAE; KIM, SANG-BEOM; CHUNG, KI WHA; CHOI, BYUNG-OK

    2016-01-01

    Mutations in the optic atrophy 1 gene (OPA1) are associated with autosomal dominant optic atrophy and 20% of patients demonstrate extra-ocular manifestations. In addition to these autosomal dominant cases, only a few syndromic cases have been reported thus far with compound heterozygous OPA1 mutations, suggestive of either recessive or semi-dominant patterns of inheritance. The majority of these patients were diagnosed with Behr syndrome, characterized by optic atrophy, ataxia and peripheral neuropathy. The present study describes a 10-year-old boy with Behr syndrome presenting with early-onset severe optic atrophy, sensorimotor neuropathy, ataxia and congenital cataracts. He had optic atrophy and was declared legally blind at six years old. Electrophysiological, radiological, and histopathological findings were compatible with axonal sensorimotor polyneuropathy. At birth, he presented with a congenital cataract, which has not been previously described in patients with OPA1 mutations. Whole exome sequencing indicated a pair of novel compound heterozygous mutations: p.L620fs*13 (c.1857–1858delinsT) and p.R905Q (c.G2714A). Neither mutation was observed in controls (n=300), and thus, they were predicted to be pathogenic by multiple in silico analyses. The mutation sites were highly conserved throughout different vertebrate species. The patients parents did not have any ophthalmic or neurologic symptoms and the results of electrophysiological studies were normal, suggestive of an autosomal recessive pattern of inheritance. The present study identified novel compound heterozygous OPA1 mutations in a patient with recessive optic atrophy, sensorimotor neuropathy and congenital cataracts, indicating an expansion of the clinical spectrum of pathologies associated with OPA1 mutations. Thus, OPA1 gene screening is advisable in the workup of patients with recessive optic atrophy, particularly with Behr syndrome and cataracts. PMID:27150940

  15. Design of an LED-based compound optical system for a driving beam system.

    PubMed

    Ge, Aiming; Wang, Wei; Du, Zhengqing; Qiu, Peng; Wang, Junwei; Cai, Jinlin; Song, Xiaobo

    2013-04-20

    This paper proposes an LED-based compound optical system, which can be involved in the design of the driving beam system in automotive headlamps with high system efficiency and low power consumption. The compound system can meet the requirements announced in the UNECE regulation "Addendum 111: Regulation No. 112 Revision 2." Also, it is composed of a nonspherical reflector, a compound lens, and a two-dimensional diverging lens. Using a single device of high-brightness LED of merely 7.6 W, the specified illumination requirements for the driving beam can be achieved. As we have expected, on the test screen at a distance of 25 m, the simulation results, as well as the testing results for the prototype, can reach the illuminance distribution requirements, including all specified regions and key points. Moreover, this compound system enjoys the features of high compactness, high energy efficiency, and feasibility of manufacturing. PMID:23669678

  16. N-Monosubstituted Methoxy-oligo(ethylene glycol) Carbamate Ester Prodrugs of Resveratrol.

    PubMed

    Mattarei, Andrea; Azzolini, Michele; Zoratti, Mario; Biasutto, Lucia; Paradisi, Cristina

    2015-01-01

    Resveratrol is a natural polyphenol with many interesting biological activities. Its pharmacological exploitation in vivo is, however, hindered by its rapid elimination via phase II conjugative metabolism at the intestinal and, most importantly, hepatic levels. One approach to bypass this problem relies on prodrugs. We report here the synthesis, characterization, hydrolysis, and in vivo pharmacokinetic behavior of resveratrol prodrugs in which the OH groups are engaged in an N-monosubstituted carbamate ester linkage. As promoiety, methoxy-oligo(ethylene glycol) groups (m-OEG) (CH₃-[OCH₂CH₂]n-) of defined chain length (n = 3, 4, 6) were used. These are expected to modulate the chemico-physical properties of the resulting derivatives, much like longer poly(ethylene glycol) (PEG) chains, while retaining a relatively low MW and, thus, a favorable drug loading capacity. Intragastric administration to rats resulted in the appearance in the bloodstream of the prodrug and of the products of its partial hydrolysis, confirming protection from first-pass metabolism during absorption. PMID:26404221

  17. Turnover capacity of Coprinus cinereus peroxidase for phenol and monosubstituted phenols

    SciTech Connect

    Aitken, M.D.; Heck, P.E.

    1998-05-01

    Coprinus cinereus peroxidase (CIP) and other peroxidases are susceptible to mechanism-based inactivation during the oxidation of phenolic substrates. The turnover capacity of CIP was quantified for phenol and 11 monosubstituted phenols under conditions in which enzyme inactivation by mechanisms involving hydrogen peroxide alone were minimized. Turnover capacities varied by nearly 2 orders of magnitude, depending on the substituent. On a mass basis, the enzyme consumption corresponding to the lowest turnover capacities is considerable and may influence the economic feasibility of proposed industrial applications of peroxidases. Within a range of substituent electronegativity values, molar turnover capacities correlated well (r{sup 2} = 0.89) with substituent effects quantified by radical {sigma} values and semiquantitatively with homolytic O-H bond dissociation energies of the phenolic substrates, suggesting that phenoxyl radical intermediates are probably involved in the suicide inactivation of CIP. The correlation range in each case did not include phenols with highly electron-withdrawing (nitro and cyano) substituents because they are not oxidized by CIP, nor phenols with highly electron-donating (hydroxy and amino) substituents because they led to virtually complete inactivation of the enzyme with minimal substrate removal.

  18. Supercritical water oxidation kinetics and pathways for ethylphenols, hydroxyacetophenones, and other monosubstituted phenols

    SciTech Connect

    Martino, C.J.; Savage, P.E.

    1999-05-01

    The authors examined the decomposition of o-, m-, and p-ethylephenol and o-, m-, and p-hydroxyacetophenone in dilute aqueous solutions at 460 C and 25.3 MPa, both in the presence and absence of added oxygen. In the absence of oxygen, the ethylphenols produced vinylphenols as the major product and the hydroxyacetophenones produced phenol, benzendiols, and hydroxybenzaldehydes. In the presence of oxygen, ethylphenols and hydroxyacetophenones reacted through two major parallel paths and one minor path. The major primary paths for ethylphenols were to vinylphenols and to ring-opening products and ultimately CO{sub 2}. The minor path was to phenol. For hydroxyacetophenones, the major primary paths were to phenol and to ring-opening products and ultimately CO{sub 2}. The minor path was to hydroxybenzaldehydes. The relative rates of these parallel paths were sensitive to the location of the substituent. Although reactions did occur in the absence of oxygen, the disappearance rates were much slower than those observed during oxidation. Power-law global rate expressions were developed for reactant disappearance during oxidation. These rate laws were used along with rate laws previously reported for other monosubstituted phenols to examine the relative oxidation rates for different phenols. All of the substituted phenols oxidized more quickly than phenol itself. The oxidation rates for the substituted phenols were functions of both the identity and location of the substituent. For a given substituent, the reactivity was always in the order ortho > para > meta for all of the substituted phenols examined.

  19. Thermal lens and all optical switching of new organometallic compound doped polyacrylamide gel

    NASA Astrophysics Data System (ADS)

    Badran, Hussain Ali

    In this work thermal lens spectrometry (TLS) is applied to investigate the thermo-optical properties of new organometallic compound containing azomethine group, Dichloro bis [2-(2-hydroxybenzylideneamino)-5-methylphenyl] telluride platinum(II), doped polyacrylamide gel using transistor-transistor logic (TTL) modulated cw 532 nm laser beam as an excitation beam modulated at 10 Hz frequency and probe beam wavelength 635 nm at 14 mW. The technique is applied to determine the thermal diffusivities, ds/dT and the linear thermal expansion coefficient of the sample. All-optical switching effects with low background and high stability are demonstrated.

  20. Speckle reduction in optical coherence tomography by "path length encoded" angular compounding.

    PubMed

    Iftimia, N; Bouma, B E; Tearney, G J

    2003-04-01

    Speckle, the dominant factor reducing image quality in optical coherence tomography (OCT), limits the ability to identify cellular structures that are essential for diagnosis of a variety of diseases. We describe a new high-speed method for implementing angular compounding by path length encoding (ACPE) for reducing speckle in OCT images. By averaging images obtained at different incident angles, with each image encoded by path length, ACPE maintains high-speed image acquisition and requires minimal modifications to OCT probe optics. ACPE images obtained from tissue phantoms and human skin in vivo demonstrate a qualitative improvement over traditional OCT and an increased SNR that correlates well with theory. PMID:12683852

  1. Two-photon absorption and optical-limiting properties of a novel organic compound

    NASA Astrophysics Data System (ADS)

    Ye, Lihua; Zhang, Junxiang; Cui, Yiping; Li, Zhenhua; He, Anzhi

    2002-09-01

    The two-photon absorption and applications become the hot points in the recent photoelectronic material research field. The two-photon absorption materials can be applied to many fields such as up-conversion lasing, optical limiting, optical stabilization, three-dimension optical storage, three-dimension micro-machining, et al. Especially studies of optical power limiting have become more interesting to the research community because of the need for automatic protection of optical sensors against intense laser radiation. Here we report the observation of the TPA and optical power limiting property of a novel double conjugated molecule DSBDR1 in solution. The linear absorption spectral is observed using a scanning spectrophotometer. Using Nd:YAG laser pulse as exciting laser, the incident pulse energy and the transmitted pulse energy are respectively recorded by an energy meter. Then we obtain the nonlinear absorption coefficient of the novel double conjugated molecule in THF. Figures show that the molecule exhibts the large TPA cross-section and excellent optical limiting at 1064 nm. The nonlinear absorption mechanism of the novel organic compound is finally analyzed.

  2. Polarimeter with linear response for measuring optical activity in organic compounds

    NASA Astrophysics Data System (ADS)

    Flores, Jorge L.; Montoya, Marcial; Garcia-Torales, G.; Gonzalez Alvarez, Alejandro

    2005-08-01

    A polarimeter designed for measuring small rotation angles on the polarization plane of light is described. The experimental device employs one fixed polarizer and a rotating analyzer. The system generates a periodical intensity signal, which is then Fourier analyzed. The coefficients of Fourier Transform contain information about rotation angles produced by organic compounds that exhibited optical activity. The experimental device can be used to determine the sugar concentration in agave juice.

  3. TRANSFORMATION OF DYES AND RELATED COMPOUNDS IN ANOXIC SEDIMENT: KINETICS AND PRODUCTS

    EPA Science Inventory

    The reactions of several azo, anthraquinone, and quinoline dyes were studied in settled sediments. everal 1-substituted anthraquinones were lost from sediment with half-lives less than 10 days. For monosubstituted 1-amino and 1-methylamino (Disperse Red 9) compounds, the most sta...

  4. Optical properties of Group X-XII intermetallic compounds studied by HR-EELS.

    PubMed

    Sato, Yohei; Terauchi, Masami; Kameoka, Satoshi; Tsai, An-Pang

    2014-11-01

    Electronic structure of d orbital states in transition metals is a key factor for their physical properties and chemical functions. Copper and intermetallic compound PdZn have good catalysis function for the methanol steam reforming reaction. Tsai et al. showed that from results of XPS measurements the d electronic structure of PdZn was similar with that of copper, and the catalysis function should be related to the d electron states [1]. This similarity of d electronic states leads to another view point of the mechanism for coloring the intermetallic compounds. It is well-known that the characteristic red color of copper is caused by interband transition from the d electrons. Therefore, PdZn and Group X-XII intermetallic compounds are expected to be colored and the optical properties should depend on the d electronic states. In this study, the relations between optical properties and d electron states of Group X-XII intermetallic compounds were investigated by using high energy-resolution electron energy-loss spectroscopy (HR-EELS) based on transmission electron microscopy (TEM). From the relation between optical properties and d electronic states, the mechanism of colored intermetallic compounds will be discussed.Figure shows the optical reflectivity of NiZn, PdZn and PtZn, which were derived from EELS spectra by Kramers-Kronig analysis. Intensity drops (arrows) of the reflectivity were observed in visible energy region. These are caused by the interband transitions from d electronic states. The energy positions of the reflectivity drops have tendency of shifting to higher energy side with increasing atomic number of Group X elements (Ni → Pd → Pt). This indicates that the transition energies of d electrons become larger with the atomic number of the elements. First principle calculations (WIEN2k) confirmed that the interband transitions of d electronic states were excitations from bonding d states to hybrid states of anti-bonding s, p, and d states of Group

  5. Simple strategy for synthesis of optically active allylic alcohols and amines by using enantioselective organocatalysis

    PubMed Central

    Jiang, Hao; Holub, Nicole; Anker Jørgensen, Karl

    2010-01-01

    A simple organocatalytic one-pot protocol for the construction of optically active allylic alcohols and amines using readily available reactants and catalyst is presented. The described reaction is enabled by an enantioselective enone epoxidation/aziridination-Wharton-reaction sequence affording two highly privileged and synthetically important classes of compounds in an easy and benign way. The advantages of the described sequence include easy generation of stereogenic allylic centers, also including quaternary stereocenters, with excellent enantio- and diastereomeric-control and high product diversity. Furthermore, using monosubstituted enones as substrates, having moderate enantiomeric excess, the one-pot reaction sequence proceeds with an enantioenrichment of the products and high diastereoselectivity was achieved. PMID:20547884

  6. Kinetic Resolution of Racemic Allylic Alcohols by Catalytic Asymmetric Substitution of the OH Group with Monosubstituted Hydrazines.

    PubMed

    Yan, Liang; Xu, Jing-Kun; Huang, Chao-Fan; He, Zeng-Yang; Xu, Ya-Nan; Tian, Shi-Kai

    2016-09-01

    A new strategy has been established for the kinetic resolution of racemic allylic alcohols through a palladium/sulfonyl-hydrazide-catalyzed asymmetric OH-substitution under mild conditions. In the presence of 1 mol % [Pd(allyl)Cl]2 , 4 mol % (S)-SegPhos, and 10 mol % 2,5-dichlorobenzenesulfonyl hydrazide, a range of racemic allylic alcohols were smoothly resolved with selectivity factors of more than 400 through an asymmetric allylic alkylation of monosubstituted hydrazines under air at room temperature. Importantly, this kinetic resolution process provided various allylic alcohols and allylic hydrazine derivatives with high enantiopurity. PMID:27339655

  7. Depths-encoded angular compounding for speckle reduction in optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Cao, Zhaoyuan; Qian, Jie; Chen, Xinjian; Mo, Jianhua

    2016-03-01

    Optical coherence tomography (OCT) is one of the successful inventions in medical imaging as a clinic routine in the past decades. This imaging technique is based on low coherence interferometer and consequently suffers from speckle noise inherently, which can degrade image quality and obscure micro-structures. Therefore, effective speckle reduction techniques have been always desired and researched since optical coherence tomography was invented. In this study, we proposed an angular compounding method to reduce speckle noise of OCT image. Two different angular light paths are created on the sample arm using two beam splitters. The epi-detection scheme creates three different combinations of the two angular light paths above, which produce three images in single B-scan. To compound these three images, these three images are separated in depth by delaying one light path relative to the other. Compared to those reported angular compounding methods, our method showed an advantage of faster imaging speed. This method was evaluated on an artificial eye model. The results demonstrated a 1.46-fold improvement in speckle contrast.

  8. Optical analysis of a compound quasi-microscope for planetary landers

    NASA Technical Reports Server (NTRS)

    Wall, S. D.; Burcher, E. E.; Huck, F. O.

    1974-01-01

    A quasi-microscope concept, consisting of facsimile camera augmented with an auxiliary lens as a magnifier, was introduced and analyzed. The performance achievable with this concept was primarily limited by a trade-off between resolution and object field; this approach leads to a limiting resolution of 20 microns when used with the Viking lander camera (which has an angular resolution of 0.04 deg). An optical system is analyzed which includes a field lens between camera and auxiliary lens to overcome this limitation. It is found that this system, referred to as a compound quasi-microscope, can provide improved resolution (to about 2 microns ) and a larger object field. However, this improvement is at the expense of increased complexity, special camera design requirements, and tighter tolerances on the distances between optical components.

  9. Polymer optical fiber compound parabolic concentrator tip for enhanced coupling efficiency for fluorescence based glucose sensors

    PubMed Central

    Hassan, Hafeez Ul; Nielsen, Kristian; Aasmul, Soren; Bang, Ole

    2015-01-01

    We demonstrate that the light excitation and capturing efficiency of fluorescence based fiber-optical sensors can be significantly increased by using a CPC (Compound Parabolic Concentrator) tip instead of the standard plane-cut tip. We use Zemax modelling to find the optimum CPC tip profile and fiber length of a polymer optical fiber diabetes sensor for continuous monitoring of glucose levels. We experimentally verify the improved performance of the CPC tipped sensor and the predicted production tolerances. Due to physical size requirements when the sensor has to be inserted into the body a non-optimal fiber length of 35 mm is chosen. For this length an average improvement in efficiency of a factor of 1.7 is experimentally demonstrated and critically compared to the predicted ideal factor of 3 in terms of parameters that should be improved through production optimization. PMID:26713213

  10. [Techniques of on-line monitoring volatile organic compounds in ambient air with optical spectroscopy].

    PubMed

    Du, Zhen-Hui; Zhai, Ya-Qiong; Li, Jin-Yi; Hu, Bo

    2009-12-01

    Volatile organic compounds (VOCs) are harmful gaseous pollutants in the ambient air. The techniques of on-line monitoring VOCs are very significant for environment protection. Until now, there is no single technology that can meet all the needs of monitoring various VOCs. The characteristics and present situation of several optical methods, which can be applied to on-line monitoring VOCs, including non dispersive infrared (NDIR), Fourier transform infrared (FTIR) spectroscopy, differential optical absorption spectroscopy (DOAS), and laser spectroscopy were reviewed. Comparison was completed between the national standard methods and spectroscopic method for measuring VOCs. The main analysis was focused on the status and trends of tuning diode laser absorption spectroscopy (TDLAS) technology. PMID:20210131

  11. Asymmetric bioreduction of activated alkenes to industrially relevant optically active compounds

    PubMed Central

    Winkler, Christoph K.; Tasnádi, Gábor; Clay, Dorina; Hall, Mélanie; Faber, Kurt

    2012-01-01

    Ene-reductases from the ‘Old Yellow Enzyme’ family of flavoproteins catalyze the asymmetric reduction of various α,β-unsaturated compounds at the expense of a nicotinamide cofactor. They have been applied to the synthesis of valuable enantiopure products, including chiral building blocks with broad industrial applications, terpenoids, amino acid derivatives and fragrances. The combination of these highly stereoselective biocatalysts with a cofactor recycling system has allowed the development of cost-effective methods for the generation of optically active molecules, which is strengthened by the availability of stereo-complementary enzyme homologues. PMID:22498437

  12. Magneto-optical spectroscopy of Co{sub 2}FeSi Heusler compound

    SciTech Connect

    Veis, M. Beran, L.; Antos, R.; Legut, D.; Hamrle, J.; Pistora, J.; Sterwerf, Ch.; Meinert, M.; Schmalhorst, J.-M.; Kuschel, T.; Reiss, G.

    2014-05-07

    Magneto-optical and electronic properties of the Co{sub 2}FeSi Heusler compound were studied by polar Kerr magneto-optical spectroscopy and ab-initio calculations. The thin-film samples were grown by dc/rf magnetron co-sputtering on MgO(100) substrates. A Cr seed layer was deposited prior to the Co{sub 2}FeSi layer to achieve its epitaxial growth. The magneto-optical spectroscopy was carried out using generalized magneto-optical ellipsometry with rotating analyzer in the photon energy range from 1.4 to 5.5 eV with an applied magnetic field of up to 1.2 T. The polar Kerr spectra showed a smooth spectral behavior up to 5.5 eV indicating nearly free charge carriers. Experimental data were compared with ab-initio calculations based on density functional theory employing the full-potential linearized augmented plane wave method.

  13. Stable synthetic mono-substituted cationic bacteriochlorins mediate selective broad-spectrum photoinactivation of drug-resistant pathogens at nanomolar concentrations

    PubMed Central

    Huang, Liyi; Krayer, Michael; Roubil, John G. S.; Huang, Ying-Ying; Holten, Dewey; Lindsey, Jonathan S.; Hamblin, Michael R.

    2014-01-01

    A set of three stable synthetic mono-substituted cationic bacteriochlorins (BC37, BC38 and BC39) were recently reported to show exceptional activity (low nanomolar) in mediating photodynamic killing of human cancer cells after a 24 h incubation upon excitation with near-infrared light (730 nm). The presence of cationic quaternary ammonium groups in each compound suggested likely activity as antimicrobial photosensitizers. Herein this hypothesis was tested against a panel of pathogenic microorganisms that have all recently drawn attention due to increased drug-resistance (Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis; Gram-negative bacteria, Escherichia coli and Acinetobacter baumannii; and fungal yeasts Candida albicans and Cryptococcus neoformans). All three bacteriochlorins were highly effective against both Gram-positive species (> 6 logs of eradication at ≤ 200 nM and 10 J/cm2). The dicationic bacteriochlorin (BC38) was best against the Gram-negative species (> 6 logs at 1–2 μM) and the lipophilic monocationic bacteriochlorin (BC39) was best against the fungi (> 6 logs at 1 μM). The bacteriochlorins produced substantial singlet oxygen (and apparently less Type-1 reactive-oxygen species such as hydroxyl radical) as judged by activation of fluorescent probes and comparison with 1H-phenalen-1-one-2-sulfonic acid; the order of activity was BC37 > BC38 > BC39. A short incubation time (30 min) resulted in selectivity for microbial cells over HeLa human cells. The highly active photodynamic inactivation of microbial cells may stem from the amphiphilic and cationic features of the bacteriochlorins. PMID:25463659

  14. Conformational stability, r0 structural parameters, and vibrational assignments of mono-substituted cyclobutanes: Fluorocyclobutane

    NASA Astrophysics Data System (ADS)

    Ganguly, Arindam; Klaassen, Joshua J.; Guirgis, Gamil A.; Gounev, Todor K.; Durig, James R.

    2011-08-01

    Variable temperature (-55 to -100 °C) studies of the infrared spectra (3500-400 cm -1) of fluorocyclobutane, c-C 4H 7F, dissolved in liquid xenon have been carried out as well as the infrared spectra of the gas. By utilizing eight pairs of conformers at 10 different temperatures, the enthalpy difference between the more stable equatorial conformer and the axial form has been determined to be 496 ± 40 cm -1 (5.93 ± 0.48 kJ/mol). The percentage of the axial conformer present at ambient temperature is estimated to be 8 ± 1%. The ab initio MP2(full) average predicted energy difference from a variety of basis sets is 732 ± 47 cm -1 (9.04 ± 0.44 kJ/mol) and the average value of 602 ± 20 cm -1 from density functional theory predictions by the B3LYP method are significantly larger than the experimentally determined enthalpy value. By utilizing previously reported microwave rotational constants for the equatorial and axial conformers combined with ab initio MP2(full)/6-311+G(d,p) predicted structural values, adjusted r0 parameters have been obtained. The determined heavy atom structural parameters for the equatorial [axial] conformer are: distances (Å) C-F = 1.383(3) [1.407(3)], C α-C β = 1.543(3) [1.546(3)], C β-C γ = 1.554(3) [1.554(3)] and angles (°) ∠C αC βC γ = 85.0(5) [89.2(5)], ∠C βC αC β = 89.3(5) [89.2(5)], ∠F-(C βC αC β) = 117.4(5) [109.2(5)] and a puckering angle of 37.4(5) [20.7(5)]. The conformational stabilities, harmonic force fields, infrared intensities, Raman activities, depolarization ratios and vibrational frequencies have been obtained for both conformers from MP2(full)/6-31G(d) ab initio calculations and compared to experimental values where available. The results are discussed and compared to the corresponding properties of some other monosubstituted cyclobutanes with halogen and pseudo-halogen substituents.

  15. Effective medium approximation of the optical properties of electrochromic cerium-titanium oxide compounds

    SciTech Connect

    Rottkay, K. von; Richardson, T.; Rubin, M.; Slack, J.

    1997-07-01

    Cerium titanium oxide samples derived from a solution have been compared against sputtered films over a wide range of different compositions. X-ray diffraction was used to investigate the structural properties of the compound material existing in a two-phase mixture M{sub A}O{sub 2}-M{sub B}O{sub 2}. The optical properties were evaluated over the whole solar spectrum by variable angle spectroscopic ellipsometry combined with spectrophotometry. The spectral complex refractive index was determined for CeO{sub 2} and TiO{sub 2}, as well as for their compounds. To reduce the large number of permutations in composition of multi-component oxides it would be useful to be able to predict the properties of the mixtures from the pure oxide components. Therefore these results were compared to those obtained by effective medium theory utilizing the optical constants of CeO{sub 2} and TiO{sub 2}. In order to investigate the performance as passive counter-electrode in Li{sup +} based electrochromic devices the films were tested by cyclic voltammetry with in-situ transmission control. Chemical composition was measured by Rutherford backscattering spectrometry. Surface morphology was analyzed by atomic force microscopy.

  16. Effective medium approximation of the optical properties of electrochromic cerium-titanium oxide compounds

    NASA Astrophysics Data System (ADS)

    von Rottkay, Nik; Richardson, Terry J.; Rubin, Michael; Slack, J.; Masetti, Enrico; Dautzenberg, G.

    1997-10-01

    Cerium titanium oxide samples produced by sol-gel have been compared against sputtered and pulsed laser deposited films over a wide range of different compositions. X-ray diffraction was used to investigate the structural properties of the compound material existing in a two-phase mixture MAO2-MBO2. The optical properties were evaluated over the whole solar spectrum by variable angle spectroscopic ellipsometry combined with spectrophotometry. The spectral complex refractive index was determined for CeO2 and TiO2, as well as for their compounds. To reduce the large number of permutations in composition of multi-component oxides it would be useful to be able to predict the properties of the mixtures from the pure oxide components. Therefore these results were compared to those obtained by effective medium theory utilizing the optical constants of CeO2 and TiO2. In order to investigate the performance as passive counter-electrode in Li+ based electrochromic devices the films were tested by cyclic voltammetry with in-situ transmission control. Chemical composition was measured by Rutherford backscattering spectrometry. Surface morphology was analyzed by atomic force microscopy.

  17. Microstructure and optical characterizations of mechanosynthesized nanocrystalline semiconducting ZrTiO4 compound

    NASA Astrophysics Data System (ADS)

    Dutta, Hema; Nandy, Anshuman; Pradhan, S. K.

    2016-08-01

    A ZrO2-TiO2 solid solution is obtained by high energy ball milling of equimolar mixture of monoclinic (m) ZrO2 and anatase (a) TiO2. Nanocrystalline orthorhombic ZrTiO4 compound is initiated from the nucleation of TiO2-ZrO2 solid solution with isostructural s-TiO2 (srilankite) base after 30 min of milling. After 12 h of milling, 95 mol% non-stoichiometric ZrTiO4 phase is formed. Post-annealing of 12 h ball-milled powder mixture at 1073 K for 1 h in open air results in complete formation of stoichiometric ZrTiO4 compound. Microstructures of all powder mixtures milled for different durations have been characterized by Rietveld's structure and microstructure refinement method using X-ray powder diffraction data. HRTEM images of 12 h milled and annealed samples provide direct evidence of the results obtained from the Rietveld analysis. Optical bandgaps of ball milled and annealed ZrTiO4 compounds lie within the semiconducting region (~2.0 eV) and increases with increase in milling time.

  18. A novel sensing mechanism for optic detection of aromatic compounds including chlorophenols

    SciTech Connect

    Zhao, Shishan; Luong, J.H.T.

    1995-12-01

    Development of chemosensors and new sensing mechanisms is encouraging for the detection of environmentally and biologically important species. This paper presents a novel design of optic chemosensors for small aromatic compounds including chlorophenols, which represent a large part of the organic pollutants. Cap-shaped assemblies are prepared from the torus-shaped cyclodextrins (CyDs) and planar porphyrin (POR). The assemblies exhibit an intensive absorption maximum at 420.5 nm and is sensitive to the inclusion of guest molecules. For highly selective recognition of an analyte, the necessary condition is the affinity of its hydrophobic benzene ring to the CyD cavity and the sufficient condition is the interaction between its hydrogen-bonding functional group(s) and the porphyrin cycle.

  19. Detection of Organic Compounds in Water by an Optical Absorbance Method

    PubMed Central

    Kim, Chihoon; Eom, Joo Beom; Jung, Soyoun; Ji, Taeksoo

    2016-01-01

    This paper proposes an optical method which allows determination of the organic compound concentration in water by measurement of the UV (ultraviolet) absorption at a wavelength of 250 nm~300 nm. The UV absorbance was analyzed by means of a multiple linear regression model for estimation of the total organic carbon contents in water, which showed a close correlation with the UV absorbance, demonstrating a high adjusted coefficient of determination, 0.997. The comparison of the TOC (total organic carbon) concentrations for real samples (tab water, sea, and river) calculated from the UV absorbance spectra, and those measured by a conventional TOC analyzer indicates that the higher the TOC value the better the agreement. This UV absorbance method can be easily configured for real-time monitoring water pollution, and built into a compact system applicable to industry areas. PMID:26742043

  20. Low-energy optical phonon modes in the caged compound LaRu2Zn20

    NASA Astrophysics Data System (ADS)

    Wakiya, K.; Onimaru, T.; Tsutsui, S.; Hasegawa, T.; Matsumoto, K. T.; Nagasawa, N.; Baron, A. Q. R.; Ogita, N.; Udagawa, M.; Takabatake, T.

    2016-02-01

    We have investigated atomic dynamics of caged compound LaRu2Zn20 by the measurements of specific heat C and inelastic x-ray scattering (IXS). The lattice part of the specific heat Clat divided by T3,Clat /T3, shows a broad peak at around 15 K, which is reproduced by two Einstein modes with characteristic temperatures of θE 1=35 K and θE 2=82 K, respectively. IXS measurements along the [111] and [110] directions reveal weakly dispersive phonon modes at 3 meV (35 K) and 7 meV (80 K), respectively, whose values agree with the values of θE's. The first-principles calculation has assigned the 3 meV phonon modes as the optical modes of Zn atoms located at the middle of two La atoms, which is likely to lead to the structural instability.

  1. Detection of Organic Compounds in Water by an Optical Absorbance Method.

    PubMed

    Kim, Chihoon; Eom, Joo Beom; Jung, Soyoun; Ji, Taeksoo

    2016-01-01

    This paper proposes an optical method which allows determination of the organic compound concentration in water by measurement of the UV (ultraviolet) absorption at a wavelength of 250 nm~300 nm. The UV absorbance was analyzed by means of a multiple linear regression model for estimation of the total organic carbon contents in water, which showed a close correlation with the UV absorbance, demonstrating a high adjusted coefficient of determination, 0.997. The comparison of the TOC (total organic carbon) concentrations for real samples (tab water, sea, and river) calculated from the UV absorbance spectra, and those measured by a conventional TOC analyzer indicates that the higher the TOC value the better the agreement. This UV absorbance method can be easily configured for real-time monitoring water pollution, and built into a compact system applicable to industry areas. PMID:26742043

  2. Optical Evidence of Itinerant-Localized Crossover of 4f Electrons in Cerium Compounds

    NASA Astrophysics Data System (ADS)

    Kimura, Shin-ichi; Kwon, Yong Seung; Matsumoto, Yuji; Aoki, Haruyoshi; Sakai, Osamu

    2016-08-01

    Cerium (Ce)-based heavy-fermion materials have a characteristic double-peak structure (mid-IR peak) in the optical conductivity [σ(ω)] spectra originating from the strong conduction (c)-f electron hybridization. To clarify the behavior of the mid-IR peak at a low c-f hybridization strength, we compared the σ(ω) spectra of the isostructural antiferromagnetic and heavy-fermion Ce compounds with the calculated unoccupied density of states and the spectra obtained from the impurity Anderson model. With decreasing c-f hybridization intensity, the mid-IR peak shifts to the low-energy side owing to the renormalization of the unoccupied 4f state, but suddenly shifts to the high-energy side owing to the f-f on-site Coulomb interaction at a slight localized side from the quantum critical point (QCP). This finding gives us information on the change in the electronic structure across QCP.

  3. Long lifetime, high density single-crystal erbium compound nanowires as a high optical gain material

    NASA Astrophysics Data System (ADS)

    Yin, Leijun; Ning, Hao; Turkdogan, Sunay; Liu, Zhicheng; Nichols, Patricia L.; Ning, C. Z.

    2012-06-01

    Erbium-containing materials of long lifetime and high Er density are important for achieving strong luminescence and high optical gain in compact integrated photonics devices. We have systematically studied the lifetime and crystal quality as a function of growth conditions for an erbium compound that we recently reported, erbium chloride silicate (ECS). The lifetime for the best quality ECS nanowires can be as long as 540 μs, the longest for high-density Er-materials, representing a lifetime-density product as high as 8.7 × 1018 s cm-3. Such high density, long lifetime erbium materials can find many interesting applications such as compact lasers or amplifiers.

  4. Compound prism design principles, III: linear-in-wavenumber and optical coherence tomography prisms

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    We extend the work of the first two papers in this series [Appl. Opt. 50, 4998–5011 (2011), Appl. Opt. 50, 5012–5022 (2011)] to design compound prisms for linear-in-wavenumber dispersion, especially for application in spectral domain optical coherence tomography (OCT). These dispersive prism designs are believed to be the first to meet the requirements of high resolution OCT systems in direct-view geometry, where they can be used to shrink system size, to improve light throughput, to reduce stray light, and to reduce errors resulting from interpolating between wavelength- and wavenumber-sampled domains. We show prism designs that can be used for thermal sources or for wideband superluminescent diodes centered around wavelengths 850, 900, 1300, and 1375 nm. PMID:22423147

  5. Second-order nonlinear optical Langmuir-Blodgett films based on a series of azo rare-earth coordination compounds

    SciTech Connect

    Gao, L.H.; Wang, K.Z.; Huang, C.H.

    1995-06-01

    A series of novel azo dyes composed of a lanthanide complex anion and an azo cation, in which strongly electron-donating (dihexadecylamino)phenyl and electron-accepting pyridinium groups are separated by an azo group, was designed as second-order nonlinear optical Langmuir-Blodgett (LB) film materials. The compounds are of good film-forming properties. The values of second-order molecular hyperpolarizability {beta} were determined to be (1.20-3.03) x 10{sup {minus}27} esu, comparable to the largest value known for azo LB materials. The compounds studied may be attactive in the application in future optical devices. 13 refs., 5 figs., 1 tab.

  6. Thresholds of optical limiting in solutions of nanoscale compounds of zinc phthalocyanine with galactopyranosyl radicals

    NASA Astrophysics Data System (ADS)

    Mikheev, G. M.; Angelov, I. P.; Mantareva, V. N.; Mogileva, T. N.; Mikheev, K. G.

    2013-07-01

    The optical limiting (OL) of nanosecond laser pulses in solutions of newly synthesized dyes in dimethyl sulfoxide (DMSO) has been investigated. These dyes are compounds of zinc phthalocyanine (ZnPc) with D-galactopyranosyl radicals (Gal) located in the peripheral ( p-GalZnPc) and nonperipheral ( n-GalZnPc) positions with respect to the ZnPc macrocycle. Experiments have been performed using laser radiation with a wavelength of 532 nm, at which the optical absorbance of solutions of ZnPc, p-GalZnPc and n-GalZnPc dyes is four orders of magnitude lower than the absorbance in the peaks at wavelengths of 671, 680, and 701 nm, respectively. It is established that solutions of p-GalZnPc and n-GalZnPc in DMSO have a much lower OL threshold in comparison with ZnPc solution; the nonlinearity of p-GalZnPc solutions exceeds that of n-GalZnPc solutions. OL thresholds for the dyes under study in a wide concentration range are determined.

  7. Theoretical Analysis of X-ray Compound Refractive Lens Optical Properties

    SciTech Connect

    Kohn, V.; Snigireva, I.; Snigirev, A.

    2004-05-12

    We present a theoretical analysis of optical properties of parabolic compound refractive lenses (CRL). The parabolic CRL with a large number of elements is considered as a parabolic medium along the x-ray path. The problem of x-ray coherent wave propagation inside such a medium is solved exactly. The analytical formula is obtained for the parabolic CRL imaging propagator as a parabolic wave with complex parameters due to absorption of x rays inside the lens. The fast and universal computer program is developed for simulating the CRL generated images. An imaging example of a test object as a silicon plate of 3 {mu}m thickness with a round hole of 3 {mu}m diameter is presented and discussed in details. The main optical parameters of parabolic CRL such as an effective aperture, a diffraction limited resolution and a focal distance are calculated analytically and discussed. It is shown that parabolic CRL has no spherical aberration while long single plano-concave and bi-concave lenses have.

  8. Electronic, Magnetic and Optical Properties of Two Fe-based Superconductors and Related Parent Compounds

    SciTech Connect

    Jin, Rongying; Pan, Minghu; He, Xiaobo; Li, G. R.; Li, De; Peng, Ru-wen; Thompson, James R; Sales, Brian C; Sefat, A. S.; McGuire, Michael A; Mandrus, David; Wendelken, J F; Keepens, V.; Plummer, E. W.

    2010-01-01

    We have investigated the electronic, magnetic, and optical properties of two Fe-based superconductors and related parent compounds via three powerful techniques: scanning tunneling microscopy/spectroscopy (STM/S), high-temperature vibrating sample magnetometer (VSM), and optical transmission spectroscopy (OTS). Below the superconducting transition temperature Tc ~ 48 K, the STM/S of polycrystalline NdFeAsO0.86F0.14 reveals a single-gap feature. The quantitative fitting of STS data results in BCS like temperature dependence of the energy gap (T), with 2 (0)/kBTc ~ 4.3. Surprisingly, the tunneling spectra of BaFe2As2 single crystals show no evidence for the opening of a gap below its magnetic/structural transition temperature TMS ~ 140 K. This transition also had little impact on the transmission spectra in the wavelength range between 400 and 2400 nm. But its effect to the magnetic properties is dramatic, as reflected by the unusual magnetic susceptibility in a wide temperature range.

  9. Optoelectronic properties and holographic optical recording of a dithienylperfluorocyclopentene compound having two phenanthryl units

    NASA Astrophysics Data System (ADS)

    Yang, T. S.; Pu, S. Z.; Liu, G.; Yao, B. L.; Wang, Y. L.; Lei, M.

    2007-12-01

    A phenanthrenyl-substituted diarylethene derivative (1,2-bis[5-phenanthryl-2-methylthiophen-3-yl] perfluorocyclopentene, Ph-BMTFP) has been synthesized and its optoelectronic properties have been investigated. The photochromic reactivity of Ph-BMTFP was examined in hexane solution as well as in poly(methyl methacrylate) (PMMA) amorphous film. Upon irradiation with 313 nm UV light, the colorless solution turned purple, in which a visible absorption band was observed at 555 nm. In PMMA film, the new broad absorption band at λ max = 580 nm appeared when it was irradiated by 313 nm UV light. The compound exhibited good fluorescence in hexane solution and its fluorescence intensity decreased along with the photochromic reactivity upon irradiation with 313 nm UV light. This property could be potentially applied to high-density optical memory with fluorescence readout method. The holographic optical storage was performed successfully using Ph-BMTFP as the recording medium and polarization multiplexing holograms recording can effectively increase the information storage capacity of the holographic data storage.

  10. Exploratory synthesis in molten salts: Characterization, nonlinear optical and phase-change properties of new chalcophosphate compounds

    NASA Astrophysics Data System (ADS)

    Chung, In

    The polychalcophosphate flux technique has played an important role in discovery of new chalcophosphate compounds via access to low and intermediate temperature of 160--600°C. Chalcophosphates are compounds that possess phosphorus and chalcogen atoms with P-Q bond, where Q = S, Se, or Te. The structural diversity within the class of metal chalcophosphates is extensive, and members of this family can exhibit technologically important ion-exchange, intercalation, magnetic, electrical, and optical properties. In the present work exploratory synthesis of chalcophosphate compounds using polychalcophosphate molten salt method and characterization of physicochemical properties that are mainly concentrate upon nonlinear optical properties and crystal-glass phase-change behavior are described. Chapters 2-6 focus on the effort of systematic study of alkali metal selenophosphate ternary compounds. The first family of this class is one-dimensional compounds, APSe6 (A = K, Rb, Cs) and A2P2Se6 (A = K, Rb). The compounds adopt noncentrosymmetric polar space group and exhibited remarkably strong second harmonic generation response in both crystalline and glassy phases. They also show a reversible crystal-glass phase-change behavior. By coupling noncentrosymmetry in crystal structure and phase-change behavior, we proposed general fabrication strategy for optical glassy fibers that yield strong, intrinsic, second-order nonlinear optical properties. The APSe 6 (A = K, Rb) glassy optical fiber exhibited waveguided second harmonic and difference frequency generation. The second family of this class is phosphorus-rich, novel molecular complex salts of Rb4P 6Se12, Cs4P6Se12, and Cs 5P5Se12. All compounds feature low valent P in two different formal oxidation states. We attempted rational synthetic conditions to stabilize less oxidized phosphorus compounds by utilizing excess P in the flux. The polychalcophosphate flux also produced rare phosphorus telluride compound. The new compound K4

  11. Optical contrast spectra studies for determining thickness of stage-1 graphene-FeCl3 intercalation compounds

    NASA Astrophysics Data System (ADS)

    Han, Wen-Peng; Li, Qiao-Qiao; Lu, Yan; Yan, Xu; Zhao, Hui; Long, Yun-Ze

    2016-07-01

    Because of novel features in their structural, electronic, magnetic and optical properties, especially potential applications in nanoelectronics, the few-layer graphene intercalation compounds (FLGICs) have been intensively studied recently. In this work, the dielectric constant of the doped graphene of stage-1 FeCl3-GIC is obtained by fitting the optical contrast spectra. And fully intercalated stage-1 FeCl3-FLGICs were prepared by micromechanical cleavage method from graphite intercalation compounds (GICs) for the first time. Finally, we demonstrated that the thickness of stage-1 FeCl3-GICs by micromechanical cleavage can be determined by optical contrast spectra. This method also can be used to other FLGICs, such as SbCl5-FLGICs and AuCl5-FLGICs, etc.

  12. A stereo-compound hybrid microscope for combined intracellular and optical recording of invertebrate neural network activity.

    PubMed

    Frost, William N; Wang, Jean; Brandon, Christopher J

    2007-05-15

    Optical recording studies of invertebrate neural networks with voltage-sensitive dyes seldom employ conventional intracellular electrodes. This may in part be due to the traditional reliance on compound microscopes for such work. While such microscopes have high light-gathering power, they do not provide depth of field, making working with sharp electrodes difficult. Here we describe a hybrid microscope design, with switchable compound and stereo objectives, that eases the use of conventional intracellular electrodes in optical recording experiments. We use it, in combination with a voltage-sensitive dye and photodiode array, to identify neurons participating in the swim motor program of the marine mollusk Tritonia. This microscope design should be applicable to optical recording studies in many preparations. PMID:17306887

  13. Analysis of the structural, electronic and optic properties of Ni doped MgSiP2 semiconductor chalcopyrite compound

    NASA Astrophysics Data System (ADS)

    Kocak, Belgin; Ciftci, Yasemin Oztekin

    2016-03-01

    The structural, electronic band structure and optic properties of the Ni doped MgSiP2 chalcopyrite compound have been performed by using first-principles method in the density functional theory (DFT) as implemented in Vienna Ab-initio Simulation Package (VASP). The generalized gradient approximation (GGA) in the scheme of Perdew, Burke and Ernzerhof (PBE) is used for the exchange and correlation functional. The present lattice constant (a) follows generally the Vegard's law. The electronic band structure, total and partial density of states (DOS and PDOS) are calculated. We present data for the frequency dependence of imaginary and real parts of dielectric functions of Ni doped MgSiP2. For further investigation of the optical properties the reflectivity, refractive index, extinction coefficient and electron energy loss function are also predicted. Our obtained results indicate that the lattice constants, electronic band structure and optical properties of this compound are dependent on the substitution concentration of Ni.

  14. Speckle reduction process based on digital filtering and wavelet compounding in optical coherence tomography for dermatology

    NASA Astrophysics Data System (ADS)

    Gómez Valverde, Juan J.; Ortuño, Juan E.; Guerra, Pedro; Hermann, Boris; Zabihian, Behrooz; Rubio-Guivernau, José L.; Santos, Andrés.; Drexler, Wolfgang; Ledesma-Carbayo, Maria J.

    2015-07-01

    Optical Coherence Tomography (OCT) has shown a great potential as a complementary imaging tool in the diagnosis of skin diseases. Speckle noise is the most prominent artifact present in OCT images and could limit the interpretation and detection capabilities. In this work we propose a new speckle reduction process and compare it with various denoising filters with high edge-preserving potential, using several sets of dermatological OCT B-scans. To validate the performance we used a custom-designed spectral domain OCT and two different data set groups. The first group consisted in five datasets of a single B-scan captured N times (with N<20), the second were five 3D volumes of 25 Bscans. As quality metrics we used signal to noise (SNR), contrast to noise (CNR) and equivalent number of looks (ENL) ratios. Our results show that a process based on a combination of a 2D enhanced sigma digital filter and a wavelet compounding method achieves the best results in terms of the improvement of the quality metrics. In the first group of individual B-scans we achieved improvements in SNR, CNR and ENL of 16.87 dB, 2.19 and 328 respectively; for the 3D volume datasets the improvements were 15.65 dB, 3.44 and 1148. Our results suggest that the proposed enhancement process may significantly reduce speckle, increasing SNR, CNR and ENL and reducing the number of extra acquisitions of the same frame.

  15. Tunability of optical nonlinear response through twisting of conjugation paths in push-pull biphenyl compounds

    NASA Astrophysics Data System (ADS)

    Boeglin, Alex; Fort, Alain F.; Mager, Loic; Combellas, Catherine; Thiebault, Andre; Rodriguez, Vincent

    2001-12-01

    Charge separated molecules with strong zwitterionic character make especially interesting species for quadratic Non Linear Optical (NLO) doped materials because of their large dipole moments and rather large quadratic hyperpolarizabilities. Furthermore, their sensitivity to the dielectric environment brands them as good candidates for checking the validity of formalisms relating geometrical structure and NLO properties. We have carried out an experimental and theoretical study on two phenoxide pyridinium derivatives with different inter ring twist angle, combining UV-visible, IR and NLO spectroscopies supplemented by semi-empirical and density functional calculations. Experimentally, changing the polarity of the solvent allows us to explore only a small range of twist angles. However, changing the pyridinium nitrogen atom from para to meta position gives essentially the same compound but with a larger twist angle. Changes in solvent polarity and position substitution give rise to a combined enhancement of the quadratic response by an order of magnitude, showing experimentally the possibility of tuning NLO properties of chromophores to be used as doping agents in NLO applications.

  16. Intrinsic fiber optic absorption sensors for the detection of volatile organic compounds

    SciTech Connect

    Klunder, G.L.; Russo, R.E.

    1994-12-31

    Extensive contamination of ground water from organic solvents has placed a large emphasis on the development of instruments for remote in-situ sensing. Fiber optic chemical sensors (FOCSs) have made a great deal of progress in this area. The authors have investigated two intrinsic FOCSs for the detection of volatile organic compounds. One is based on evanescent wave absorption and the other is a direct absorption core-based sensor. Both sensors make use of silicone polymers as selective membranes to extract the volatile analyte from the aqueous solution for analysis in the NIR. The rate limiting step for analyte diffusion into the membrane has been determined to be diffusion through the Nernstian boundary. With each sensor, the times required to reach an equilibrium response are on the order of 30 minutes for 20 ppm aqueous solution of trichloroethylene. Headspace measurements are much faster and reach equilibrium in 3-5 minutes. A comparison of the two sensors, detection limits, diffusion rates and effects of temperature will be discussed.

  17. Optical, transport and magnetic properties of new compound CeCd3P3

    NASA Astrophysics Data System (ADS)

    Higuchi, Shohei; Noshima, Yuki; Shirakawa, Naoki; Tsubota, Masami; Kitagawa, Jiro

    2016-05-01

    We have found that CeCd3P3 crystallizes into a hexagonal ScAl3C3-type structure. The optical, transport and magnetic properties of CeCd3P3 were investigated by measuring the diffuse reflectance, electrical resistivity and magnetization. CeCd3P3 is a semiconductor with a fundamental band gap of approximately 0.75 eV. The 4f electrons of Ce3+ ions are well localized but do not show long-range order down to 0.48 K, presumably due to the geometrical frustration of Ce atoms. The magnetic ordering temperature is possibly lower than that of isostructural CeZn3P3 (0.75 K). Because several f-electron compounds with the ScAl3C3-type structure are quantum spin systems, CeCd3P3 may be a candidate for quantum spin liquid. On the other hand, the relatively large band gap compared to approximately 0.4 eV in CeZn3P3, would not be in accordance with the observation of the photoinduced Kondo effect, providing a potentially new range of applications for devices based on the Kondo effect.

  18. Systematic study of the electronic structure and optical properties of icosahedral boron and boron compounds

    NASA Astrophysics Data System (ADS)

    Li, Dong

    1997-11-01

    A systematic study of the electronic structures, total energies and optical properties of B12-based boron and boron-rich compounds and boron oxide compounds has been conducted by the first-principles orthogonalized linear combination of atomic orbitals method. The materials involved are: α-r-B12, B12As2,/ B12P2,/ B11C(CBC)/ (or/ B4C),/ B13C2,/ B12O2,/ (B10Si2)Si2,/ (B10Si2)Si2-I, B2O3-I and B2O3-II. The band structures show that α-r-B12,/ B12As2,/ B12P2,/ B11C(CBC),/ B12O2,/ (B10Si2)Si2, and (B10Si2)Si2-I are semiconductors with band gaps ranging from 1.29 eV to 3.04 eV while B13C2 is a metal with an intrinsic hole at the top of the valence band below a semiconductor-like gap. The study also shows that B2O3-I and B2O3-II are wide gap insulators with calculated LDA gaps of 6.20 eV and 8.85 eV separately. The calculated density of states are resolved into atomic and orbital partial components and the valence-charge distributions are also studied. The natural bonding characteristics in these crystals are illuminated by evaluating the Mulliken effective charges on each atom and overlap populations between pairs of atoms. It is shown that inter-icosahedral bonding is much stronger than the intra-icosahedral bonding in the B12- based crystals. The chain elements in B12As2,/ B12P2,/ (B10Si2)Si2 and (B10Si2)Si2-I donate electrons to the icosahedra, while B11C(CBC),/ B13C2 and B12O2 gain a slight amount of charge in forming strong covalent bonds. For boron oxide compounds, B2O3-II is found to be more ionic than B2O3-I. It is also concluded that the sp2 planar bonding in B2O3-I is stronger than the sp3 tetrahedral bonding in B2O3-II. The bulk moduli of α-r-B12,/ B12As2,/ B12P2,/ B11C(CBC),/ B13C2 and B12O2 are estimated by means of total energy calculation as a function of crystal volume, and are to be considered as upper limits. We have also calculated the interband optical conductivities and the complex dielectric functions. Static dielectric constants for icosahedral

  19. Organic solid state switches incorporating porphyrin compounds and method for producing organic solid state optical switches

    DOEpatents

    Wasielewski, Michael R.; Gaines, George L.; Niemczyk, Mark P.; Johnson, Douglas G.; Gosztola, David J.; O'Neil, Michael P.

    1996-01-01

    A light-intensity dependent molecular switch comprised of a compound which shuttles an electron or a plurality of electrons from a plurality of electron donors to an electron acceptor upon being stimulated with light of predetermined wavelengths, said donors selected from porphyrins and other compounds, and a method for making said compound.

  20. Electronic and optical properties of (U,Th)O2 compound from screened hybrid density functional studies

    NASA Astrophysics Data System (ADS)

    Mo, Chongjie; Yang, Yu; Kang, Wei; Zhang, Ping

    2016-04-01

    The electronic structure and optical properties for the (U,Th)O2 compound are systematically studied by employing the Heyd-Scuseria-Ernzerh method (HSE) of screened hybrid density functional. The electronic band gap of (U,Th)O2 is predicted to be 3.06 eV, in the middle of the values of UO2 and ThO2. Based on wavefunction analysis, we conclude (U,Th)O2 to be a Mott insulator in its ground state. The frequency dependent dielectric functions and optical properties are then calculated and compared with those of ThO2 and UO2. At the visible light frequency range, the adsorption coefficients for ThO2, UO2 and (U,Th)O2 are totally different, which gives an accessible method to predict the proportion of U atoms in an arbitrary unknown (U,Th)O2 compounds from the adsorption spectrum of visible lights.

  1. mBJLDA approach for optical properties of Nowontny-Juza LiMgZ (Z = P, As) compounds

    SciTech Connect

    Sharma, Arvind K.; Thakur, Jyoti Kashyap, Manish K.

    2014-04-24

    First principles approach has been utilized to investigate electronic and optical properties of LiMgZ (Z = P, As) Newontny-Juza compounds. The exchange and correlation (XC) effects are taken into account by a semi local, orbital independent modified Becke-Johnson (mBJ) potential as coupled with Local Density Approximation (LDA). The local orbital independent mBJ potential could provide better band gap/ HM gap due to its capability to catch the essentials of hybrid functionals. The positive values of real dielectric-function rule out the possibility of showing magnetism by these compounds and stabilize the semiconducting state. The shifting of peaks in optical spectra towards high energy is due to increasing indirect band gap from LiMgP to LiMgAs.

  2. Object-Based Classification of Wetlands Using Optical and SAR Data with a Compound Kernel in Support Vector Machine (SVM)

    NASA Astrophysics Data System (ADS)

    Salehi, B.; Mahdavi, S.; Brisco, B.; Huang, W.

    2015-12-01

    Both Synthetic Aperture RADAR (SAR) and optical imagery play a pivotal role in many applications. Thus it is desirable to fuse the two independent sources of data congruously. Many of the fusion methods, however, fail to consider the different nature of SAR and optical data. Moreover, it is not straightforward to adjust the contribution of the two data sources with respect to the application. Support Vector Machine (SVM) is one of the classification methods which can provide the possibility of combination of two kinds of images considering the different nature of them. It is particularly useful when object-based classification is used, in which case features extracted from SAR and optical images can be treated differently. This paper aims to develop an object-based classification method using both optical and SAR data which treats the two data sources independently. For the implementation of the method, a RapidEye and a RADARSAT-2 Quad-polarimetric image over Avalon Peninsula in Newfoundland, Canada will be used for wetland classification. RapidEye will be segmented using multiresolution algorithm in eCognitionTM. Because of speckle, segmentation of SAR images does not have robust results. Thus the result of the segmentation from RapidEye image is superimposed on RADARSAT-2 image. Then useful SAR and optical features are extracted. Integrating features extracted from optical and SAR data, a compound kernel in SVM is applied for classification. This kernel is a combination of two kernels with different weights, each of which are for the features of one of the data sources. Using compound kernel can outperform using the same kernel for both images. The proposed method has two main advantages. First, different nature of optical and SAR images which is the result of dissimilar dynamic range, resolution, etc. is considered. Second, as the two data sources are combined with different weights, it is possible to adjust the role of each data sources for varying applications.

  3. Catalytic Addition of Simple Alkenes to Carbonyl Compounds Using Group 10 Metals

    PubMed Central

    Schleicher, Kristin D.

    2011-01-01

    Recent advances using nickel complexes in the activation of unactivated monosubstituted olefins for catalytic intermolecular carbon–carbon bond-forming reactions with carbonyl compounds, such as simple aldehydes, isocyanates, and conjugated aldehydes and ketones, are discussed. In these reactions, the olefins function as vinyl- and allylmetal equivalents, providing a new strategy for organic synthesis. Current limitations and the outlook for this new strategy are also discussed. PMID:21904421

  4. Hierarchical active factors to band gap and nonlinear optical response in Ag-containing quaternary-chalcogenide compounds

    NASA Astrophysics Data System (ADS)

    Huang, Jun-ben; Mamat, Mamatrishat; Pan, Shilie; Yang, Zhihua

    2016-07-01

    In this research work, Ag-containing quaternary-chalcogenide compounds KAg2TS4 (T=P, Sb) (I-II) and RbAg2SbS4 (III) have been studied by means of Density Functional Theory as potential IR nonlinear optical materials. The origin of wide band gap, different optical anisotropy and large SHG response is explained via a combination of density of states, electronic density difference and bond population analysis. It is indicated that the different covalent interaction behavior of P-S and Sb-S bonds dominates the band gap and birefringence. Specifically, the Ag-containing chalcogenide compound KAg2PS4 possesses wide band gap and SHG response comparable with that of AgGaS2. By exploring the origin of the band gap and NLO response for compounds KAg2TS4 (T=P, Sb), we found the determination factor to the properties is different, especially the roles of Ag-d orbitals and bonding behavior of P-S or Sb-S. Thus, the compounds KAg2TS4 (T=P, Sb) and RbAg2SbS4 can be used in infrared (IR) region.

  5. Structural and optical properties of II-VI and III-V compound semiconductors

    NASA Astrophysics Data System (ADS)

    Huang, Jingyi

    This dissertation is on the study of structural and optical properties of some III-V and II-VI compound semiconductors. The first part of this dissertation is a study of the deformation mechanisms associated with nanoindentation and nanoscratching of InP, GaN, and ZnO crystals. The second part is an investigation of some fundamental issues regarding compositional fluctuations and microstructure in GaInNAs and InAlN alloys. In the first part, the microstructure of (001) InP scratched in an atomic force microscope with a small diamond tip has been studied as a function of applied normal force and crystalline direction in order to understand at the nanometer scale the deformation mechanisms in the zinc-blende structure. TEM images show deeper dislocation propagation for scratches along <110> compared to <100>. High strain fields were observed in <100> scratches, indicating hardening due to locking of dislocations gliding on different slip planes. Reverse plastic flow have been observed in <110> scratches in the form of pop-up events that result from recovery of stored elastic strain. In a separate study, nanoindentation-induced plastic deformation has been studied in c-, a-, and m-plane ZnO single crystals and c-plane GaN respectively, to study the deformation mechanism in wurtzite hexagonal structures. TEM results reveal that the prime deformation mechanism is slip on basal planes and in some cases, on pyramidal planes, and strain built up along particular directions. No evidence of phase transformation or cracking was observed in both materials. CL imaging reveals quenching of near band-edge emission by dislocations. In the second part, compositional inhomogeneity in quaternary GaInNAs and ternary InAlN alloys has been studied using TEM. It is shown that exposure to antimony during growth of GaInNAs results in uniform chemical composition in the epilayer, as antimony suppresses the surface mobility of adatoms that otherwise leads to two-dimensional growth and

  6. Total organic carbon disappearance kinetics for the supercritical water oxidation of monosubstituted phenols

    SciTech Connect

    Martino, C.J.; Savage, P.E.

    1999-06-01

    Supercritical water oxidation (SCWO) is a process technology for destroying organic compounds present in aqueous waste streams. The authors oxidized phenols bearing single -CH{sub 3}, -C{sub 2}H{sub 5}, -COCH{sub 3}, -CHO, -OH, -OCH{sub 3}, and -NO{sub 2} substituents in supercritical water at 460 C and 25.3 MPa. The observed effects of the concentrations of total organic carbon (TOC) and oxygen on the global disappearance rates for TOC were correlated by using power-law rate expressions. This kinetics study revealed that the rate of TOC disappearance is more sensitive to the oxygen concentration than is the rate of reactant disappearance. Additionally, the rate of TOC disappearance is always slower than the rate of reactant disappearance, with the ratio of these rates ranging from 0.10 to 0.65 for the different phenols at the conditions studied. The rates of TOC disappearance during SCWO of these substituted phenols varied by nearly 2 orders of magnitude, showing significant effects from both the identity and location of the substituent. These substituent effects are greater for TOC disappearance kinetics than for reactant disappearance kinetics. Additionally, all of the substituted phenols exhibit faster TOC disappearance rates than does phenol. Accordingly, phenol is a good worst case model compound for SCWO studies. The pronounced substituent effects for TOC disappearance rates indicate that the oxidation of a common refractory intermediate is not an important feature of the SCWO networks for these phenols at the conditions studied.

  7. The structural, electronic and optical response of IIA-VIA compounds through the modified Becke-Johnson potential

    NASA Astrophysics Data System (ADS)

    Ali, Roshan; Mohammad, S.; Ullah, Hamid; Khan, S. A.; Uddin, H.; Khan, M.; Khan, N. U.

    2013-02-01

    The structural, electronic and optical properties of IIA-VIA compounds are performed, by using the full-potential linearized augmented plan wave (FP-LAPW) method within DFT, by using the (PBEsol-GGA 2008) version. We have compared the modified Becke-Johnson (mBJ) potential to LDA, GGA and EV-GGA approximations. The IIA-VIA compounds have rock salt structure (B1) and zinc-blend structure (B3). The results obtained for band structure using mBJ show a significant improvement over previous theoretical work and give closer values to the experimental results. The bandgaps less than 3.1 eV are used in the visible light devices applications, while those with bandgaps bigger than 3.1 eV, used in UV devices applications. Optical parameters, like the dielectric constant, refractive indices, reflectivity, optical conductivity and absorption coefficient are calculated and analyzed. Refractive index lesser than unity (vg=c/n) shows that the group velocity of the incident radiation is greater than the speed of light.

  8. Chemical degradation of fluorosulfonamide fuel cell membrane polymer model compounds

    NASA Astrophysics Data System (ADS)

    Alsheheri, Jamela M.; Ghassemi, Hossein; Schiraldi, David A.

    2014-12-01

    The durability of a polymer electrolyte fuel cell membrane, along with high proton conductivity and mechanical performance is critical to the success of these energy conversion devices. Extending our work in perfluorinated membrane stability, aromatic trifluoromethyl sulfonamide model compounds were prepared, and their oxidative degradation was examined. The chemical structures for the models were based on mono-, di- and tri-perfluorinated sulfonamide modified phenyl rings. Durability of the model compounds was evaluated by exposure to hydroxyl radicals generated using Fenton reagent and UV irradiation of hydrogen peroxide. LC-MS results for the mono-substituted model compound indicate greater stability to radical oxidation than the di-substituted species; loss of perfluorinated fonamide side chains appears to be an important pathway, along with dimerization and aromatic ring hydroxylation. The tri-substituted model compound also shows loss of side chains, with the mono-substituted compound being a major oxidation product, along with a limited amount of hydroxylation and dimerization of the starting material.

  9. Structural, elastic, electronic, magnetic and optical properties of RbSrX(C, SI, Ge) half-Heusler compounds

    NASA Astrophysics Data System (ADS)

    Ahmad, Mukhtar; Naeemullah; Murtaza, G.; Khenata, R.; Bin Omran, S.; Bouhemadou, A.

    2015-03-01

    In this study we present investigations pertaining to structural, elastic, electronic, magnetic and optical properties of RbSrC, RbSrSi and RbSrGe half-Heusler compounds. To carry out this study, full potential (FP) linearized augmented plane wave (LAPW), a scheme of calculations developed within the framework of density functional theory (DFT), is employed. To incorporate the exchange correlation (XC) energy and corresponding potential into the total energy calculations, generalized gradient approximation (GGA) parameterized by Wu-Cohen is taken into account. Analysis of band structures and densities of states (DOS) profiles illustrate the conducting nature in spin down state and the semiconducting nature in spin-up state. The bonding nature discussed via electron charge density plot reveals strong ionic bonding character of these compounds. At ambient conditions, calculations for elastic constants (Cij) and their related elastic moduli are also performed which point to their brittle character. The compounds are found to be ferromagnetic with 1 μB. The magnetic moment decreases from its integer value at high pressures for these compounds.

  10. Enhanced Optical Transmission and Sensing of a Thin Metal Film Perforated with a Compound Subwavelength Circular Hole Array

    NASA Astrophysics Data System (ADS)

    Zhang, Xiangnan; Liu, Guiqiang; Liu, Zhengqi; Hu, Ying; Cai, Zhengjie

    2015-12-01

    We propose and numerically investigate the optical transmission behaviors of a sub-wavelength metal film perforated with a two-dimensional square array of compound circular holes. Enhanced optical transmission is obtained by using the finite-difference time-domain (FDTD) method, which can be mainly attributed to the excitation and coupling of localized surface plasmon resonances (LSPRs) and surface plasmon polaritons (SPPs), and Fano Resonances. The redshift of the transmission peak can be achieved by enlarging the size and number of small holes, the environmental dielectric constant. These indicate that the proposed structure has potential applications in integrated optoelectronic devices such as plasmonic filters and sensors. supported by National Natural Science Foundation of China (Nos. 11464019, 11264017, 11004088), Young Scientist Development Program of China (No. 20142BCB23008) and the Natural Science Foundation of Jiangxi Province, China (Nos. 2014BAB212001, 20112BBE5033)

  11. Optical Properties of the Charge-Density-Wave Polychalcogenide Compounds R2Te5 (R=Nd, Sm and Gd)

    SciTech Connect

    Pfuner, F.; Degiorgi, L.; Shin, K.Y.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2010-02-15

    We investigate the rare-earth polychalcogenide R{sub 2}Te{sub 5} (R = Nd, Sm and Gd) charge-density-wave (CDW) compounds by optical methods. From the absorption spectrum we extract the excitation energy of the CDW gap and estimate the fraction of the Fermi surface which is gapped by the formation of the CDW condensate. In analogy to previous findings on the related RTe{sub n} (n = 2 and 3) families, we establish the progressive closing of the CDW gap and the moderate enhancement of the metallic component upon chemically compressing the lattice.

  12. High-throughput microfluidics and ultrafast optics for in vivo compound/genetic discoveries

    NASA Astrophysics Data System (ADS)

    Rohde, Christopher B.; Gilleland, Cody; Samara, Chrysanthi; Yanik, M. Fatih

    2010-02-01

    Therapeutic treatment of spinal cord injuries, brain trauma, stroke, and neurodegenerative diseases will greatly benefit from the discovery of compounds that enhance neuronal regeneration following injury. We previously demonstrated the use of femtosecond laser microsurgery to induce precise and reproducible neural injury in C. elegans, and have developed microfluidic on-chip technologies that allow automated and rapid manipulation, orientation, and non-invasive immobilization of animals for sub-cellular resolution two-photon imaging and femtosecond-laser nanosurgery. These technologies include microfluidic whole-animal sorters, as well as integrated chips containing multiple addressable incubation chambers for exposure of individual animals to compounds and sub-cellular time-lapse imaging of hundreds of animals on a single chip. Our technologies can be used for a variety of highly sophisticated in vivo high-throughput compound and genetic screens, and we performed the first in vivo screen in C. elegans for compounds enhancing neuronal regrowth following femtosecond microsurgery. The compounds identified interact with a wide variety of cellular targets, such as cytoskeletal components, vesicle trafficking, and protein kinases that enhance neuronal regeneration.

  13. Electronic and Optical Properties of Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) Antiperovskite Compounds

    NASA Astrophysics Data System (ADS)

    Iqbal, Samad; Murtaza, G.; Khenata, R.; Mahmood, Asif; Yar, Abdullah; Muzammil, M.; Khan, Matiullah

    2016-08-01

    The electronic and optical properties of cubic antiperovskites Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) were investigated by applying the full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) scheme based on density functional theory. Different exchange correlation potentials were adopted for the calculations. The results of band structure and density of states show that, by changing the central anion of Ca3MN, the nature of the materials change from metallic (Ca3GeN, Ca3SnN, Ca3PbN) to semiconducting with small band gaps (Ca3SbN and Ca3BiN) to insulating (Ca3PN and Ca3AsN). The optical properties such as dielectric function, absorption coefficient, optical conductivity, reflectivity and refractive indices have also been calculated. The results reveal that all the studied compounds are optically active in the visible and ultraviolet energy regions, and therefore can be effectively utilized for optoelectronic devices.

  14. Electronic and Optical Properties of Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) Antiperovskite Compounds

    NASA Astrophysics Data System (ADS)

    Iqbal, Samad; Murtaza, G.; Khenata, R.; Mahmood, Asif; Yar, Abdullah; Muzammil, M.; Khan, Matiullah

    2016-05-01

    The electronic and optical properties of cubic antiperovskites Ca3MN (M = Ge, Sn, Pb, P, As, Sb and Bi) were investigated by applying the full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) scheme based on density functional theory. Different exchange correlation potentials were adopted for the calculations. The results of band structure and density of states show that, by changing the central anion of Ca3MN, the nature of the materials change from metallic (Ca3GeN, Ca3SnN, Ca3PbN) to semiconducting with small band gaps (Ca3SbN and Ca3BiN) to insulating (Ca3PN and Ca3AsN). The optical properties such as dielectric function, absorption coefficient, optical conductivity, reflectivity and refractive indices have also been calculated. The results reveal that all the studied compounds are optically active in the visible and ultraviolet energy regions, and therefore can be effectively utilized for optoelectronic devices.

  15. Racemization and the origin of optically active organic compounds in living organisms

    NASA Technical Reports Server (NTRS)

    Bada, J. L.; Miller, S. L.

    1987-01-01

    The organic compounds synthesized in prebiotic experiments are racemic mixtures. A number of proposals have been offered to explain how asymmetric organic compounds formed on the Earth before life arose, with the influence of chiral weak nuclear interactions being the most frequent proposal. This and other proposed asymmetric syntheses give only sight enantiomeric excess and any slight excess will be degraded by racemization. This applies particularly to amino acids where half-lives of 10(5)-10(6) years are to be expected at temperatures characteristic of the Earth's surface. Since the generation of chiral molecules could not have been a significant process under geological conditions, the origins of this asymmetry must have occurred at the time of the origin of life or shortly thereafter. It is possible that the compounds in the first living organisms were prochiral rather than chiral; this is unlikely for amino acids, but it is possible for the monomers of RNA-like molecules.

  16. High-speed guided-wave electro-optic modulators and polarization converters in III-V compound semiconductors

    NASA Astrophysics Data System (ADS)

    Rahmatian, Farnoosh

    In the last few decades, the need for electronic communication has increased by several orders of magnitude. Due to the rapid growth of the demand for transmission bandwidth, development of very high-speed communication systems is crucial. This thesis describes integrated-optic electro-optic modulators using travelling-wave electrodes in compound semiconductors for ultra-high-speed guided-wave optical communications. Both Mach-Zehnder (MZ) interferometric modulators and polarization converters (PC) have been studied with particular emphasis on the latter ones. Slow-wave travelling-wave electrodes in compound semiconductors have previously been proposed and demonstrated. Here, a study of slow-wave, travelling-wave electrodes on compound semiconductors has been performed in order to significantly improve their use in ultra-wide-band guided-wave electro-optic devices. The most important factors limiting the high frequency performance of such devices, in general, are the microwave-lightwave velocity mismatch and the microwave loss on the electrodes. Based on the deeper understanding acquired through our study, we have designed, fabricated, and tested low-loss, slow-wave, travelling-wave electrodes on semi- insulating GaAs (SI-GaAs) and AlGaAs/GaAs substrates. Microwave-to-lightwave velocity matching within 1% was achieved using slow-wave coplanar strip electrodes; many of the electrodes had effective microwave indices in the range 3.3 to 3.4 (measured at frequencies up to 40 GHz). For the electrodes fabricated on SI-GaAs substrates, microwave losses of 0.22 Np/cm and 0.34 Np/cm (average values at 40 GHz) were measured for the slow-wave coplanar strip and the slow-wave coplanar waveguide electrodes, respectively. For the electrodes fabricated on the AlGaAs/GaAs substrates containing the modulators, the corresponding losses were, on average, 0.17 Np/cm higher at 40 GHz. For the first time, ultra-wide-band polarization converters using slow-wave electrodes have been

  17. Giant magneto-optical Raman effect in a layered transition metal compound

    PubMed Central

    Ji, Jianting; Zhang, Anmin; Fan, Jiahe; Li, Yuesheng; Wang, Xiaoqun; Zhang, Jiandi; Plummer, E. W.; Zhang, Qingming

    2016-01-01

    We report a dramatic change in the intensity of a Raman mode with applied magnetic field, displaying a gigantic magneto-optical effect. Using the nonmagnetic layered material MoS2 as a prototype system, we demonstrate that the application of a magnetic field perpendicular to the layers produces a dramatic change in intensity for the out-of-plane vibrations of S atoms, but no change for the in-plane breathing mode. The distinct intensity variation between these two modes results from the effect of field-induced broken symmetry on Raman scattering cross-section. A quantitative analysis on the field-dependent integrated Raman intensity provides a unique method to precisely determine optical mobility. Our analysis is symmetry-based and material-independent, and thus the observations should be general and inspire a new branch of inelastic light scattering and magneto-optical applications. PMID:26884198

  18. Giant magneto-optical Raman effect in a layered transition metal compound.

    PubMed

    Ji, Jianting; Zhang, Anmin; Fan, Jiahe; Li, Yuesheng; Wang, Xiaoqun; Zhang, Jiandi; Plummer, E W; Zhang, Qingming

    2016-03-01

    We report a dramatic change in the intensity of a Raman mode with applied magnetic field, displaying a gigantic magneto-optical effect. Using the nonmagnetic layered material MoS2 as a prototype system, we demonstrate that the application of a magnetic field perpendicular to the layers produces a dramatic change in intensity for the out-of-plane vibrations of S atoms, but no change for the in-plane breathing mode. The distinct intensity variation between these two modes results from the effect of field-induced broken symmetry on Raman scattering cross-section. A quantitative analysis on the field-dependent integrated Raman intensity provides a unique method to precisely determine optical mobility. Our analysis is symmetry-based and material-independent, and thus the observations should be general and inspire a new branch of inelastic light scattering and magneto-optical applications. PMID:26884198

  19. Optical studies of magnons, excitons and polarons in CuO{sub 2}-layer compounds

    SciTech Connect

    Kastner, M.A.; Birgeneau, R.J.

    1996-12-31

    The optical properties of undoped and lightly doped lamellar copper oxides are reviewed. In the undoped materials the absorption below the charge-transfer gap is dominated by magnetic and crystal field excitations of the CuO{sub 2} layers. The temperature dependence of the charge-transfer absorption provides evidence that free charged excitations form large polarons. However, the optical ionization energy of holes bound to acceptors is much larger than the thermal ionization energy, indicating that the bound polarons are small. The parameters extracted from optical measurements predict the Hall mobility of holes in lightly doped La{sub 2}CuO{sub 4}, with no adjustable parameters, confirming that the carriers are polarons.

  20. A complete series of 6-deoxy-monosubstituted tetraalkylammonium derivatives of α-, β-, and γ-cyclodextrin with 1, 2, and 3 permanent positive charges

    PubMed Central

    Popr, Martin; Hybelbauerová, Simona

    2014-01-01

    Summary An efficient synthetic route toward the preparation of a complete series of monosubstituted tetraalkylammonium cyclodextrin (CD) derivatives is presented. Monotosylation of native CDs (α-, β-, γ-) at position 6 gave the starting material. Reaction of monotosylate (mono-Ts-CD) with 45% aqueous trimethylamine gave CDs substituted with one cationic functional group in a single step. Derivatives equipped with a substituent containing two cationic sites separated by an ethylene or a propylene linker were prepared by reacting mono-Ts-CD with neat N,N,N’-trimethylethane-1,2-diamine or N,N,N’-trimethylpropane-1,3-diamine and subsequent methylation by CH3I in good yields. Finally, analogues bearing a moiety with three tetraalkylammonium sites were synthesized by reacting mono-Ts-CD with bis(3-aminopropyl)amine and subsequent methylation. The majority of the presented reactions are very straightforward with a simple work-up, which avoids the need of chromatographic separation. Thus, these reactions are suitable for the multigram-scale production of monosubstituted cationic CDs. PMID:24991293

  1. Retrieval of the atmospheric compounds using a spectral optical thickness information

    SciTech Connect

    Ioltukhovski, A.A.

    1995-03-01

    A spectral inversion technique for retrieval of the atmospheric gases and aerosols contents is proposed. This technique based upon the preliminary measurement or retrieval of the spectral optical thickness. The existence of a priori information about the spectral cross sections for some of the atmospheric components allows to retrieve the relative contents of these components in the atmosphere. Method of smooth filtration makes possible to estimate contents of atmospheric aerosols with known cross sections and to filter out other aerosols; this is done independently from their relative contribution to the optical thickness.

  2. Spectral imaging of chemical compounds using multivariate optically enhanced filters integrated with InGaAs VGA cameras

    NASA Astrophysics Data System (ADS)

    Priore, Ryan J.; Jacksen, Niels

    2016-05-01

    Infrared hyperspectral imagers (HSI) have been fielded for the detection of hazardous chemical and biological compounds, tag detection (friend versus foe detection) and other defense critical sensing missions over the last two decades. Low Size/Weight/Power/Cost (SWaPc) methods of identification of chemical compounds spectroscopy has been a long term goal for hand held applications. We describe a new HSI concept for low cost / high performance InGaAs SWIR camera chemical identification for military, security, industrial and commercial end user applications. Multivariate Optical Elements (MOEs) are thin-film devices that encode a broadband, spectroscopic pattern allowing a simple broadband detector to generate a highly sensitive and specific detection for a target analyte. MOEs can be matched 1:1 to a discrete analyte or class prediction. Additionally, MOE filter sets are capable of sensing an orthogonal projection of the original sparse spectroscopic space enabling a small set of MOEs to discriminate a multitude of target analytes. This paper identifies algorithms and broadband optical filter designs that have been demonstrated to identify chemical compounds using high performance InGaAs VGA detectors. It shows how some of the initial models have been reduced to simple spectral designs and tested to produce positive identification of such chemicals. We also are developing pixilated MOE compressed detection sensors for the detection of a multitude of chemical targets in challenging backgrounds/environments for both commercial and defense/security applications. This MOE based, real-time HSI sensor will exhibit superior sensitivity and specificity as compared to currently fielded HSI systems.

  3. Ab initio investigation of the structural, electronic, magnetic and optical properties of the perovskite TlMnX3 (X = F, Cl) compounds

    NASA Astrophysics Data System (ADS)

    Hamioud, Farida; Alghamdi, Ghadah S.; Al-Omari, Saleh; Mubarak, A. A.

    2016-03-01

    We have performed ab initio investigation of some physical properties of the perovskite TlMnX3 (X = F, Cl) compounds using the full-potential linearized augmented plane wave (FP-LAPW) method. The generalized gradient approximation (GGA) is employed as exchange-correlation potential. The calculated lattice constant and bulk modulus agree with previous studies. Both compounds are found to be elastically stable. TlMnF3 and TlMnCl3 are classified as anisotropic and ductile compounds. The calculations of the band structure of the studied compounds showed the semiconductor behavior with the indirect (M-X) energy gap. Both compounds are classified as a ferromagnetic due to the integer value of the total magnetic moment of the compounds. The different optical spectra are calculated from the real and the imaginary parts of the dielectric function and connected to the electronic structure of the compounds. The static refractive index n(0) is inversely proportional to the energy bandgap of the two compounds. Beneficial optics technology applications are predicted based on the optical spectra.

  4. Electronic Band Structure, Optical, Thermal and Bonding Properties of XMg2O4(X = Si, Ge) Spinel Compounds

    NASA Astrophysics Data System (ADS)

    Semari, F.; Ouahrani, T.; Khachai, H.; Khenata, R.; Rabah, M.; Bouhemadou, A.; Murtaza, G.; Amin, B.; Rached, D.

    2013-07-01

    Bonding nature as well as structural, optoelectronic and thermal properties of the cubic XMg2O4(X = Si, Ge) spinel compounds have been calculated using a full-potential augmented plane-wave plus local orbitals (FP-APW+lo) method within the density functional theory. The exchange-correlation potential was treated with the PBE-GGA approximation to calculate the total energy. Moreover, the modified Becke-Johnson potential (TB-mBJ) was also applied to improve the electronic band structure calculations. The computed ground-state parameters (a, B, B‧ and u) are in excellent agreements with the available theoretical data. Calculations of the electronic band structure and bonding properties show that these compounds have a direct energy band gap (Γ-Γ) with a dominated ionic character and the TB-mBJ approximation yields larger fundamental band gaps compared to those obtained using the PBE-GGA. Optical properties such as the complex dielectric function ɛ(ω), reflectivity R(ω) and energy loss function L(ω), for incident photon energy up to 40 eV, have been predicted. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the effects of pressure P and temperature T on the thermal expansion coefficient, Debye temperature and heat capacity for the considered compounds are investigated for the first time.

  5. First principles calculations of the optical and plasmonic response of Au alloys and intermetallic compounds.

    PubMed

    Keast, V J; Barnett, R L; Cortie, M B

    2014-07-30

    Pure Au is widely used in plasmonic applications even though its use is compromised by significant losses due to damping. There are some elements that are less lossy than Au (e.g. Ag or Al) but they will normally oxidize or corrode under ambient conditions. Here we examine whether alloying Au with a second element would be beneficial for plasmonic applications. In order to evaluate potential alternatives to pure Au, the density of states (DOS), dielectric function and plasmon quality factor have been calculated for alloys and compounds of Au with Al, Cd, Mg, Pd, Pt, Sn, Ti, Zn and Zr. Substitutional alloying of Au with Al, Cd, Mg and Zn was found to slightly improve the plasmonic response. Of the large number of intermetallic compounds studied, only AuAl2, Au3Cd, AuMg, AuCd and AuZn were found to be suitable for plasmonic applications. PMID:25001413

  6. First principles calculations of the optical and plasmonic response of Au alloys and intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Keast, V. J.; Barnett, R. L.; Cortie, M. B.

    2014-07-01

    Pure Au is widely used in plasmonic applications even though its use is compromised by significant losses due to damping. There are some elements that are less lossy than Au (e.g. Ag or Al) but they will normally oxidize or corrode under ambient conditions. Here we examine whether alloying Au with a second element would be beneficial for plasmonic applications. In order to evaluate potential alternatives to pure Au, the density of states (DOS), dielectric function and plasmon quality factor have been calculated for alloys and compounds of Au with Al, Cd, Mg, Pd, Pt, Sn, Ti, Zn and Zr. Substitutional alloying of Au with Al, Cd, Mg and Zn was found to slightly improve the plasmonic response. Of the large number of intermetallic compounds studied, only AuAl2, Au3Cd, AuMg, AuCd and AuZn were found to be suitable for plasmonic applications.

  7. Optical methods for creating delivery systems of chemical compounds to plant roots

    NASA Astrophysics Data System (ADS)

    Kuznetsov, Pavel E.; Rogacheva, Svetlana M.; Arefeva, Oksana A.; Minin, Dmitryi V.; Tolmachev, Sergey A.; Kupadze, Machammad S.

    2004-08-01

    Spectrophotometric and fluorescence methods have been used for creation and investigation of various systems of target delivery of chemical compounds to roots of plants. The possibility of using liposomes, incrusted by polysaccharides of the external surface of nitrogen-fixing rizospheric bacteria Azospirillum brasilense SP 245, and nanoparticles incrusted by polysaccharides of wheat roots, as the named systems has been shown. The important role of polysaccharide-polysaccharide interaction in the adsorption processes of bacteria on wheat roots has been demonstrated.

  8. The propargylic route as a short and versatile entry to optically active monofluorinated compounds.

    PubMed

    Prakesch, Michaël; Grée, Danielle; Grée, René

    2002-03-01

    Using selected models and appropriate NMR techniques, it has been demonstrated that dehydroxyfluorination in the propargylic position can be highly regio- and stereoselective. The corresponding propargylic fluorides are very useful intermediates for short preparations of stereodefined unsaturated or polyunsaturated compounds with a single fluorine atom in allylic or propargylic position. This strategy offers good means for the synthesis of chiral, nonracemic monofluorinated analogues of natural products. PMID:11900521

  9. Optical detection of phenolic compounds based on the surface plasmon resonance band of Au nanoparticles.

    PubMed

    Nezhad, M Reza Hormozi; Alimohammadi, M; Tashkhourian, J; Razavian, S Mehdi

    2008-11-01

    An indirect colorimetric method is presented for detection of trace amounts of hydroquinone (1), catechol (2) and pyrogallol (3). The reduction of AuCl4(-) to Gold nanoparticles (Au-NPs) by these phenolic compounds in the presence of cetyltrimethylammonium chloride (CTAC) produced very intense surface plasmon resonance peak of Au-NPs. The plasmon absorbance of Au-NPs allows the quantitative colorimetric detection of the phenolic compounds. The calibration curves derived from the changes in absorbance at lambda = 568 nm were linear with concentration of hydroquinone, catechol and pyrogallol in the range of 7.0 x 10(-7) to 1.0 x 10(-4)M, 6.0 x 10(-6) to 2.0 x 10(-4)M and 6.0 x 10(-7) to 1.0 x 10(-4)M, respectively. The detection limits were 5.3 x 10(-7), 2.5 x 10(-6) and 3.2 x 10(-7)M for the hydroquinone, catechol and pyrogallol, respectively. The method was applied satisfactorily to the determination of phenolic compounds in water samples and pharmaceutical formulations. PMID:18222104

  10. Response Characterization of a Fiber Optic Sensor Array with Dye-Coated Planar Waveguide for Detection of Volatile Organic Compounds

    PubMed Central

    Lee, Jae-Sung; Yoon, Na-Rae; Kang, Byoung-Ho; Lee, Sang-Won; Gopalan, Sai-Anand; Jeong, Hyun-Min; Lee, Seung-Ha; Kwon, Dae-Hyuk; Kang, Shin-Won

    2014-01-01

    We have developed a multi-array side-polished optical-fiber gas sensor for the detection of volatile organic compound (VOC) gases. The side-polished optical-fiber coupled with a polymer planar waveguide (PWG) provides high sensitivity to alterations in refractive index. The PWG was fabricated by coating a solvatochromic dye with poly(vinylpyrrolidone). To confirm the effectiveness of the sensor, five different sensing membranes were fabricated by coating the side-polished optical-fiber using the solvatochromic dyes Reinhardt's dye, Nile red, 4-aminophthalimide, 4-amino-N-methylphthalimide, and 4-(dimethylamino)cinnamaldehyde, which have different polarities that cause changes in the effective refractive index of the sensing membrane owing to evanescent field coupling. The fabricated gas detection system was tested with five types of VOC gases, namely acetic acid, benzene, dimethylamine, ethanol, and toluene at concentrations of 1, 2,…,10 ppb. Second-regression and principal component analyses showed that the response properties of the proposed VOC gas sensor were linearly shifted bathochromically, and each gas showed different response characteristics. PMID:24988381

  11. Optical coherence tomography for detection of compound action potential in Xenopus Laevis sciatic nerve

    NASA Astrophysics Data System (ADS)

    Troiani, Francesca; Nikolic, Konstantin; Constandinou, Timothy G.

    2016-03-01

    Due to optical coherence tomography (OCT) high spatial and temporal resolution, this technique could be used to observe the quick changes in the refractive index that accompany action potential. In this study we explore the use of time domain Optical Coherence Tomography (TD-OCT) for real time action potential detection in ex vivo Xenopus Laevis sciatic nerve. TD-OCT is the easiest and less expensive OCT technique and, if successful in detecting real time action potential, it could be used for low cost monitoring devices. A theoretical investigation into the order of magnitude of the signals detected by a TD-OCT setup is provided by this work. A linear dependence between the refractive index and the intensity changes is observed and the minimum SNR for which the setup could work is found to be SNR = 2 x 104.

  12. Moisture resistant and anti-reflection optical coatings produced by plasma polymerization of organic compounds

    NASA Technical Reports Server (NTRS)

    Hollahan, J. R.; Wydeven, T.

    1975-01-01

    The need for protective coatings on critical optical surfaces, such as halide crystal windows or lenses used in spectroscopy, has long been recognized. It has been demonstrated that thin, one micron, organic coatings produced by polymerization of flourinated monomers in low temperature gas discharge (plasma) exhibit very high degrees of moisture resistence, e.g., hundreds of hours protection for cesium iodide vs. minutes before degradation sets in for untreated surfaces. The index of refraction of these coatings is intermediate between that of the halide substrate and air, a condition for anti-reflection, another desirable property of optical coatings. Thus, the organic coatings not only offer protection, but improved transmittance as well. The polymer coating is non-absorbing over the range 0.4 to 40 microns with an exception at 8.0 microns, the expected absorption for C-F bonds.

  13. Photochromism induced nonlinear optical absorption enhancement and ultrafast responses of several dithienylethene compounds

    NASA Astrophysics Data System (ADS)

    Wang, Yaochuan; Yan, Yongli; Liu, Dajun; Wang, Guiqiu; Pu, Shouzhi

    2015-11-01

    The nonlinear optical properties and ultrafast dynamics of three dithienylethene photochromic derivatives (i.e., P1, P2, and P3) were investigated by two-photon fluorescence, open-aperture Z-scan, and femtosecond pump-probe experiments. Photoinduced ring-closure and ring-opening phenomena, as well as a photochromism induced nonlinear optical property enhancement, were observed. For both the ring-opening and ring-closure state, the curve exhibited an ultrafast absorption peak approximately 200 fs followed by a fast decay process (i.e., ˜1 ps) and a long decay process that had a duration longer than 5 ps. The ultrafast peak followed by a fast decay process and the long decay process were attributable to a special two-photon absorption process, the formation of a charge separation state, and the relaxation of the charge separation state, respectively. However, the magnitude of the signal under the ring-closure state is approximately fivefold greater than that of the ring-opening state, which is in good agreement with nonlinear optical results. Intramolecular charge transfer processes were observed in the dynamics curves of the P2' and P3' isomers with D- π-A and D- π-D structures.

  14. Comment on "Structural, elastic, electronic, magnetic and optical properties of RbSrX (C, SI, Ge) half-Heusler compounds"

    NASA Astrophysics Data System (ADS)

    Jalilian, Jaafar; Motiepour, Pouria

    2015-12-01

    In a recent article by Ahmad et al. (2015) [1] structural, elastic, electronic, magnetic and optical properties of RbSrX (C, Si, Ge) half-Heusler compounds have been studied by the first principles calculations. After studying this article, we found that there are some physical and computational mistakes in electronic and optical properties sections. In investigating optical properties, they did not consider intraband transitions contribution in complex dielectric function term, while this term has significant effect on optical spectra for half-metallic materials.

  15. Electrical and optical investigation on doping of II-VI compounds using radioactive isotopes

    NASA Astrophysics Data System (ADS)

    Wienecke, Marion

    2000-12-01

    Using radioactive isotopes of shallow dopants (Ag, As, Rb) as well as of native or isoelectronic elements (Se, Te, Cd, Sr) which were incorporated as host atoms and then transmuted into relevant dopants (transmutation doping) we investigated doping phenomena occurring in the wide band gap II-VI compounds CdTe, ZnTe, ZnSe and SrS by the classical methods of semiconductor physics: Hall effect, C-V and photoluminescence measurements. Thus, we could assign unambiguously defect features in electrical and photoluminescence measurements to extrinsic dopants by means of the half lives of radioactive decay. In As doped ZnSe samples we observed two states: a metastable effective mass like state and a deep state. The occurrence of the latter state is always linked with the high resistivity of As doped ZnSe crystals. The transmutation doping experiments reveal that the so-called self-compensation typical for wide band gab II-VI compounds can be overcome when the thermal treatment for dopant incorporation is time separated from its electrical activation, achieved using transmutation at room temperature. Under these conditions we found an almost one-to-one doping efficiency relative to the implanted dose. Thus, these investigations are a contribution to understanding compensation phenomena occurring due to interactions between dopants and native defects during conventional doping treatments.

  16. Density-functional study of the electronic and optical properties of the spinel compound CuIr2S4

    NASA Astrophysics Data System (ADS)

    Sarkar, Soumyajit; de Raychaudhury, Molly; Saha-Dasgupta, T.

    2009-03-01

    Using first-principles density-functional calculations we have computed the electronic and optical properties of spinel compound CuIr2S4 , which undergoes a structural phase transition, accompanied by a metal-insulator transition at a temperature of about 230 K. The nature of this transition has been discussed in the literature in terms of both the correlated singlet formation picture as well as the orbitally driven Peierls transition picture. Our first-principles calculations find little role of correlation. Our calculated reflectivity and conductivity data for both the high-temperature and low-temperature phases are found to be in good agreement with measured data by Wang [Phys. Rev. B 69, 153104 (2004)].

  17. Optically isotropy in scintillator host compounds M2LaCl5 (M=Rb, and Cs): Ab-initio study

    NASA Astrophysics Data System (ADS)

    Shwetha, G.; Vaitheeswaran, G.; Kanchana, V.

    2015-06-01

    Full potential linearized augmented plane wave method (FP-LAPW) has been used to calculate the electronic structure and optical properties of high light output scintillator host compounds M2LaCl5 (M=Rb, and Cs) with in the Tran Blaha modified Becke Johnson (TB-mBJ) potential. These are wide band gap materials with the band gap of 4.75, and 4.72 eV for Rb2LaCl5, and Cs2LaCl5 respectively. From the calculated optical properties of these compounds, we find these compounds to be optically isotropic, though they are structurally anisotropic, which is an important criteria for the ceramic scintillators.

  18. Optically isotropy in scintillator host compounds M{sub 2}LaCl{sub 5} (M=Rb, and Cs): Ab-initio study

    SciTech Connect

    Shwetha, G.; Kanchana, V.; Vaitheeswaran, G.

    2015-06-24

    Full potential linearized augmented plane wave method (FP-LAPW) has been used to calculate the electronic structure and optical properties of high light output scintillator host compounds M{sub 2}LaCl{sub 5} (M=Rb, and Cs) with in the Tran Blaha modified Becke Johnson (TB-mBJ) potential. These are wide band gap materials with the band gap of 4.75, and 4.72 eV for Rb{sub 2}LaCl{sub 5}, and Cs{sub 2}LaCl{sub 5} respectively. From the calculated optical properties of these compounds, we find these compounds to be optically isotropic, though they are structurally anisotropic, which is an important criteria for the ceramic scintillators.

  19. Compound refractive lenses as prefocusing optics for X-ray FEL radiation

    DOE PAGESBeta

    Heimann, Philip; MacDonald, Michael; Nagler, Bob; Lee, Hae Ja; Galtier, Eric; Arnold, Brice; Xing, Zhou

    2016-01-27

    The performance of X-ray free-electron laser beamlines may be limited by the angular aperture. Compound refractive lenses (CRLs) can be employed to prefocus the X-ray beam, thereby increasing the beamline transmission. A prefocusing CRL was implemented in the X-ray transport of the Matter under Extreme Conditions Instrument at the Linac Coherent Light Source. A significant improvement in the beamline transmission was calculated over the 3–10 keV photon energy range. At 5 keV, the relative X-ray intensity was measured and a factor of four increase was seen in the beamline transmission. As a result, the X-ray focus was also determined bymore » the ablation imprint method.« less

  20. Compound refractive lenses as prefocusing optics for X-ray FEL radiation.

    PubMed

    Heimann, Philip; MacDonald, Michael; Nagler, Bob; Lee, Hae Ja; Galtier, Eric; Arnold, Brice; Xing, Zhou

    2016-03-01

    The performance of X-ray free-electron laser beamlines may be limited by the angular aperture. Compound refractive lenses (CRLs) can be employed to prefocus the X-ray beam, thereby increasing the beamline transmission. A prefocusing CRL was implemented in the X-ray transport of the Matter under Extreme Conditions Instrument at the Linac Coherent Light Source. A significant improvement in the beamline transmission was calculated over the 3-10 keV photon energy range. At 5 keV, the relative X-ray intensity was measured and a factor of four increase was seen in the beamline transmission. The X-ray focus was also determined by the ablation imprint method. PMID:26917128

  1. Development of optically transparent water oxidation catalysts using manganese pyrophosphate compounds.

    PubMed

    Takashima, Toshihiro; Hotori, Yuki; Irie, Hiroshi

    2015-11-01

    One challenge in artificial photosynthetic systems is the development of active oxygen evolution catalysts composed of abundant elements. The oxygen evolution activities of manganese pyrophosphate compounds were examined in electrochemical and photochemical experiments. Electrocatalysis using calcium-manganese pyrophosphate exhibited good catalytic ability under neutral pH and an oxygen evolution reaction was driven with a small overpotential (η<100 mV). UV-vis diffuse reflectance measurements revealed that manganese pyrophosphates exhibit weak absorption in the visible light region while commonly used oxygen evolution catalysts exhibit intense absorption. Therefore, the efficient light absorption of a photocatalyst was retained even after surface modification with a manganese pyrophosphate, and photochemical oxygen evolution was achieved by using magnesium ferrite modified with manganese pyrophosphate nanoparticles under the illumination of visible light at wavelength of over 420 nm. PMID:25648929

  2. Compound refractive lenses as prefocusing optics for X-ray FEL radiation

    PubMed Central

    Heimann, Philip; MacDonald, Michael; Nagler, Bob; Lee, Hae Ja; Galtier, Eric; Arnold, Brice; Xing, Zhou

    2016-01-01

    The performance of X-ray free-electron laser beamlines may be limited by the angular aperture. Compound refractive lenses (CRLs) can be employed to prefocus the X-ray beam, thereby increasing the beamline transmission. A prefocusing CRL was implemented in the X-ray transport of the Matter under Extreme Conditions Instrument at the Linac Coherent Light Source. A significant improvement in the beamline transmission was calculated over the 3–10 keV photon energy range. At 5 keV, the relative X-ray intensity was measured and a factor of four increase was seen in the beamline transmission. The X-ray focus was also determined by the ablation imprint method. PMID:26917128

  3. Small angle x-ray scattering with a beryllium compound refractive lens as focusing optic

    SciTech Connect

    Timmann, Andreas; Doehrmann, Ralph; Schubert, Tom; Schulte-Schrepping, Horst; Hahn, Ulrich; Kuhlmann, Marion; Gehrke, Rainer; Roth, Stephan Volkher; Schropp, Andreas; Schroer, Christian; Lengeler, Bruno

    2009-04-15

    At BW4 at HASYLAB a beryllium compound refractive lens (Be-CRL) is used for the focusing in small-angle x-ray scattering experiments. Using it provides the advantages of higher long-term stability and a much easier alignment compared to a setup with focusing mirrors. In our investigations presented here, we show the advantages of using a Be-CRL in small-angle and also ultra small-angle x-ray scattering. We investigated the beam characteristics at the sample position with respect to spot size and photon flux. The spot size is comparable to that of a setup with focusing mirrors but with a gain in flux and better long-term stability. It is also shown that plane mirrors are still necessary to suppress higher order energies passing the monochromator.

  4. Luminescent optical detection of volatile electron deficient compounds by conjugated polymer nanofibers.

    PubMed

    Wade, Aidan; Lovera, Pierre; O'Carroll, Deirdre; Doyle, Hugh; Redmond, Gareth

    2015-04-21

    Optical detection of volatile electron deficient analytes via fluorescence quenching is demonstrated using ca. 200 nm diameter template-synthesized polyfluorene nanofibers as nanoscale detection elements. Observed trends in analyte quenching effectiveness suggest that, in addition to energetic factors, analyte vapor pressure and polymer/analyte solubility play an important role in the emission quenching process. Individual nanofibers successfully act as luminescent reporters of volatile nitroaromatics at sub-parts per million levels. Geometric factors, relating to the nanocylindrical geometry of the fibers and to low nanofiber substrate coverage, providing a less crowded environment around fibers, appear to play a role in providing access by electron deficient quencher molecules to the excited states within the fibers, thereby facilitating the pronounced fluorescence quenching response. PMID:25803242

  5. Encapsulation of functional organic compounds in nanoglass for optically anisotropic coatings.

    PubMed

    Stöter, Matthias; Biersack, Bernhard; Rosenfeldt, Sabine; Leitl, Markus J; Kalo, Hussein; Schobert, Rainer; Yersin, Hartmut; Ozin, Geoffrey A; Förster, Stephan; Breu, Josef

    2015-04-13

    A novel approach is presented for the encapsulation of organic functional molecules between two sheets of 1 nm thin silicate layers, which like glass are transparent and chemically stable. An ordered heterostructure with organic interlayers strictly alternating with osmotically swelling sodium interlayers can be spontaneously delaminated into double stacks with the organic interlayers sandwiched between two silicate layers. The double stacks show high aspect ratios of >1000 (typical lateral extension 5000 nm, thickness 4.5 nm). This newly developed technique can be used to mask hydrophobic functional molecules and render them completely dispersible in water. The combination of the structural anisotropy of the silicate layers and a preferred orientation of molecules confined in the interlayer space allows polymer nanocomposite films to be cast with a well-defined orientation of the encapsulated molecules, thus rendering the optical properties of the nanocoatings anisotropic. PMID:25703020

  6. High-precision optical measurements of 13C/12C isotope ratios in organic compounds at natural abundance

    PubMed Central

    Zare, Richard N.; Kuramoto, Douglas S.; Haase, Christa; Tan, Sze M.; Crosson, Eric R.; Saad, Nabil M. R.

    2009-01-01

    A continuous-flow cavity ring-down spectroscopy (CRDS) system integrating a chromatographic separation technique, a catalytic combustor, and an isotopic 13C/12C optical analyzer is described for the isotopic analysis of a mixture of organic compounds. A demonstration of its potential is made for the geochemically important class of short-chain hydrocarbons. The system proved to be linear over a 3-fold injection volume dynamic range with an average precision of 0.95‰ and 0.67‰ for ethane and propane, respectively. The calibrated accuracy for methane, ethane, and propane is within 3‰ of the values determined using isotope ratio mass spectrometry (IRMS), which is the current method of choice for compound-specific isotope analysis. With anticipated improvements, the low-cost, portable, and easy-to-use CRDS-based instrumental setup is poised to evolve into a credible challenge to the high-cost and complex IRMS-based technique. PMID:19564619

  7. A density functional theory study of magneto-electric Jones birefringence of noble gases, furan homologues, and mono-substituted benzenes

    SciTech Connect

    Fahleson, Tobias; Norman, Patrick; Coriani, Sonia; Rizzo, Antonio; Rikken, Geert L. J. A.

    2013-11-21

    We report on the results of a systematic ab initio study of the Jones birefringence of noble gases, of furan homologues, and of monosubstituted benzenes, in the gas phase, with the aim of analyzing the behavior and the trends within a list of systems of varying size and complexity, and of identifying candidates for a combined experimental/theoretical study of the effect. We resort here to analytic linear and nonlinear response functions in the framework of time-dependent density functional theory. A correlation is made between the observable (the Jones constant) and the atomic radius for noble gases, or the permanent electric dipole and a structure/chemical reactivity descriptor as the para Hammett constant for substituted benzenes.

  8. Evaluation of an evanescent fiber optic chemical sensor for monitoring aqueous volatile organic compounds

    SciTech Connect

    Blair, D.S.

    1997-04-01

    Linear chemometric algorithms were used to model the quantitative response of an evanescent fiber optic chemical sensor in aqueous mixtures with concentrations between 20 and 300 ppm. Four data sets were examined with two different experimental arrangements. Two data sets contained trichloroethene, 1,1,2 trichloroethane, and toluene. Partial Least Squares, PLS, and Principal Component Regression, PCR, algorithms performed comparably on these calibration sets with cross-validated root mean squared errors of prediction (RMSEP) for trichloroethene, 1,1,1 trichloroethane, and toluene of approximately 26, 29 and 22 ppm, respectively. The third data set contained trichloroethene, 1,1,2 trichloroethane, toluene, and chloroform and the fourth contained these four analytes as well as tetrachloroethene. Again, both chemometric algorithms performed comparably on a given data set with RMSEP for trichloroethene, 1,1,2 trichloroethane, toluene, and chloroform of approximately 6, 6, 9, and 16 ppm from the first set, and 7, 11, 13, and 31 ppm from the second set with tetrachloroethene RMSEP of 31 ppm. The decrease in the quantitative performance of the sensor for modeling toluene and chloroform upon addition of tetrachloroethene to the sample solutions is due to increased cladding absorption features in the spectral response matrix. These features overlap with the analyte absorption features of toluene and chloroform. These results suggest one of the limitations with this type of sensing format.

  9. Structural, electronic and optical properties of hexagonal TaN compound

    NASA Astrophysics Data System (ADS)

    Chen, Zhongjun; Yan, Jungan; Kuang, Zhong; Chen, Taihong; Li, Dehua

    2016-01-01

    Structural and electronic properties of hexagonal Tantalum nitride (TaN) in CoSn and WC structures are studied using the first-principle calculations. Lattice constants and electronic band structures are in an excellent agreement with the available experimental and other theoretical values. TaN in both structures studied has a metallic nature and a strong hybridization of Ta 5d and N 2p are found from the spin density of states (DOS). Meanwhile, our LSDA+U calculations predicted a strong ferromagnetic state for CoSn-type structure and an obvious paramagnetic nature for WC-type structure. No phase transition are observed within cubic and hexagonal CoSn and WC structures under high pressures. Our results show WC-type TaN is the calculated ground-state structure among the three crystallographic structures studied under 120 GPa. Optical properties show that TaN in CoSn-type structure is a better dielectric material.

  10. Learning about Structural and Optical Properties of Organic Compounds through Preparation of Functional Nanomicelles While Avoiding Hazardous Chemicals or Complicated Apparatus

    ERIC Educational Resources Information Center

    Langhals, Heinz; Eberspa¨cher, Moritz; Hofer, Alexander

    2015-01-01

    The synthesis of nanomicelles in the aqueous phase on the basis of nonhazardous detergents is described where azulene and a naphthalene tetracarboximide are used in this experiment to teach the relation between structural and optical properties of organic compounds and point out possible applications. The experiment covers many aspects of…

  11. Ab-initio and DFT methodologies for computing hyperpolarizabilities and susceptibilities of highly conjugated organic compounds for nonlinear optical applications

    NASA Astrophysics Data System (ADS)

    Karakas, A.; Karakaya, M.; Ceylan, Y.; El Kouari, Y.; Taboukhat, S.; Boughaleb, Y.; Sofiani, Z.

    2016-06-01

    In this talk, after a short introduction on the methodologies used for computing dipole polarizability (α), second and third-order hyperpolarizability and susceptibility; the results of theoretical studies performed on density functional theory (DFT) and ab-initio quantum mechanical calculations of nonlinear optical (NLO) properties for a few selected organic compounds and polymers will be explained. The electric dipole moments (μ) and dispersion-free first hyperpolarizabilities (β) for a family of azo-azulenes and a styrylquinolinium dye have been determined by DFT at B3LYP level. To reveal the frequency-dependent NLO behavior, the dynamic α, second hyperpolarizabilities (γ), second (χ(2)) and third-order (χ(3)) susceptibilites have been evaluated using time-dependent HartreeFock (TDHF) procedure. To provide an insight into the third-order NLO phenomena of a series of pyrrolo-tetrathiafulvalene-based molecules and pushpull azobenzene polymers, two-photon absorption (TPA) characterizations have been also investigated by means of TDHF. All computed results of the examined compounds are compared with their previous experimental findings and the measured data for similar structures in the literature. The one-photon absorption (OPA) characterizations of the title molecules have been theoretically obtained by configuration interaction (CI) method. The highest occupied molecular orbitals (HOMO), the lowest unoccupied molecular orbitals (LUMO) and the HOMO-LUMO band gaps have been revealed by DFT at B3LYP level for azo-azulenes, styrylquinolinium dye, push-pull azobenzene polymers and by parametrization method 6 (PM6) for pyrrolo-tetrathiafulvalene-based molecules.

  12. Influence of Ca2+ doped on structural and optical properties of RPO4 (R = Ce3+, Nd3+ and Pr3+) compounds

    NASA Astrophysics Data System (ADS)

    Lemdek, El Mokhtar; Benkhouja, Khalil; Touhtouh, Samira; Sbiaai, Khalid; Arbaoui, Abdezzahid; Bakasse, Mina; Hajjaji, Abdelowahed; Boughaleb, Yahia; Saez-Puche, Regino

    2013-11-01

    This paper investigates the effect of doping by Ca2+ ions on the structural and optical properties of RPO4 (R = Ce3+, Nd3+ and Pr3+) compounds. A simple ceramic method in air at 900 °C was used to prepare all compounds. The structural characterization of compounds was carried out by using X-ray powder diffraction (XRD) and IR spectroscopy. Optical properties were characterized by reflectance spectral data and by colorimeter. The results reveal a single monazite phase for x values up to 0.4. The lattice parameters of the synthesized samples decrease linearly with the reduction of ionic radius of the Ce3+. These rare earth phosphates based materials have a potential to be adopted for the eco-friendly colorants for paints and plastics.

  13. Detection of the volatile organic compounds emitted from paints using optical fibre long period grating modified with the mesoporous nano-scale coating

    NASA Astrophysics Data System (ADS)

    Hromadka, Jiri; James, Stephen; Davis, Frank; Tatam, Ralph P.; Crump, Derrick; Korposh, Sergiy

    2015-09-01

    An optical fibre long period grating (LPG) modified with a mesoporous film infused with a calixarene as a functional compound was employed for the detection of a mixture of volatile organic compounds (VOCs). The sensing mechanism is based on the transduction of the refractive index change induced by the complexion of the VOCs with calixarene into a change in the form of the transmission spectrum of the LPG. An LPG, modified with a calixarene-infused coating comprising 5 cycles of silica nanoparticles/poly(allylamine hydrochloride) polycation (SiO2/PAH), was exposed to mixture of VOCs emitted from paint at conditions simulating ISO standards test (16000-10).

  14. Design, synthesis and nonlinear optical properties of (E)-1-(4-substituted)-3-(4-hydroxy-3-nitrophenyl) prop-2-en-1-one compounds

    NASA Astrophysics Data System (ADS)

    Saha, Amrita; Shukla, Vijay; Choudhury, Sudip; Jayabalan, J.

    2016-06-01

    A new series of (E)-1-(4-substituted)-3-(4-hydroxy-3-nitrophenyl) prop-2-en-1-one compounds have been synthesized by Claisen-Schmidt condensation reaction. Nonlinear optical characterization were carried out using z-scan technique with nanosecond pulses. These samples are found to exhibit strong nonlinear absorption at 532 nm and the nonlinear absorption coefficient of these samples exponentially increases with the increase of phonon characteristic energy. This relation speaks the role of phonon in the origin of nonlinear absorption in these compounds. The reported dependence of optical nonlinearity of the chalcone derivatives on the phonon characteristic energy will help in designing similar class of new molecules with high nonlinear coefficients.

  15. Optical and magneto-optical properties of single crystals of RFe{sub 2} (R = Gd, Tb, Ho, and Lu) and GdCo{sub 2} intermetallic compounds

    SciTech Connect

    Lee, S.J.

    1999-02-12

    The author has studied the diagonal and off-diagonal optical conductivity of RFe{sub 2}(R = Gd, Tb, Ho, Lu) and GdCo{sub 2} single crystals grown by the flux method. Using spectroscopic ellipsometry the author has measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields between 0.5 to 1.6 T. The apparatus and calibration method are described in detail. Using magneto-optical data and optical constants he derives the experimental value of the off-diagonal conductivity components. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. He applied this TB-LMTO method to LuFe{sub 2}. The theoretical results obtained agree well with the experimental data. The oxidation effects on the diagonal part of the optical conductivity were considered using a three-phase model. The oxidation effects on the magneto-optical parameters were also considered by treating the oxide layer as a nonmagnetic thin transparent layer. These corrections change not only the magnitude but also the shape of the optical conductivity and the magneto-optical parameters.

  16. Synthesis, crystal structure and non-linear optical properties of inorganic-organic hybrid compound based on face-sharing octahedral [PbBr3]∞ chains

    NASA Astrophysics Data System (ADS)

    Ben Ahmed, A.; Feki, H.; Abid, Y.

    2015-09-01

    4-BenzylPiPeridine-PbBr3 has been synthesized. The crystal structures of the title compound have been defined by X-ray diffraction analysis and characterized by FT-IR, Raman and UV-visible instrumental methods. The recorded spectrum by UV-visible spectroscopy for the investigated compound show good transparency in the visible region. This result indicates a non-zero value of the first Hyperpolarizability. We also report DFT calculations of the electric dipole moments (μ), Polarizability (α), the first Hyperpolarizability (β) and HOMO-LUMO analysis of the title compound was theoretically investigated by Gaussian 03 package. Our results suggest that the investigated material might have microscopic nonlinear optical behavior with non-zero values.

  17. Linear and nonlinear optical properties of α-K2Hg3Ge2S8 and α-K2Hg3Sn2S8 compounds

    NASA Astrophysics Data System (ADS)

    Reshak, A. H.; Azam, Sikander

    2014-11-01

    The linear and nonlinear optical properties of α-K2Hg3Ge2S8 and α-K2Hg3Sn2S8 compounds are performed using the first-principles calculations. Particularly, we appraised the optical dielectric function and the second-harmonic generation (SHG) response. We have analyzed the linear optical properties, i.e. the real and imaginary part of the dielectric tensor, the reflectivity, refractive index, extension coefficient and energy loss function. The linear optical properties show a considerable anisotropy which is important for SHG as it is defined by the phase-matching condition. The scrutiny of the roles of diverse transitions to the SHG coefficients demonstrates that the virtual electron process is foremost. The features in the spectra of χ322(2)(ω) are successfully interrelated with the character of the linear dielectric function ε(ω) in terms of single-photon and two-photon resonances. In additional, we have calculated the first hyperpolarizability, βijk, for the dominant component at the static limit for the for α-K2Hg3Ge2S8 and α-K2Hg3Sn2S8 compounds. The calculated values of β322(ω) are 2.28 × 10-30 esu for α-K2Hg3Ge2S8 and 3.69 × 10-30 esu for α-K2Hg3Sn2S8.

  18. Circular dichroism and optical absorption spectra of mononuclear and trinuclear chiral Cu(II) amino-alcohol coordinated compounds: A combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

    2015-04-01

    Studies on the physicochemical properties of biomimetic compounds of multicopper oxidases are fundamental to understand their reaction mechanisms and catalytic behavior. In this work, electronic, optical, and chiroptical properties of copper(II) complexes with amino-alcohol chiral ligands are theoretically studied by means of time-dependent density functional theory. The calculated absorption and circular dichroism spectra are compared with experimental measurements of these spectra for an uncoordinated pseudoephedrine derivative, as well as for the corresponding mononuclear and trinuclear copper(II)-coordinated complexes. This comparison is useful to gain insights into their electronic structure, optical absorption and optical activity. The optical absorption and circular dichroism bands of the pseudoephedrine derivative are located in the UV-region. They are mainly due to transitions originated from n to π anti-bonding orbitals of the alcohol and amino groups, as well as from π bonding to π anti-bonding orbitals of carboxyl and phenyl groups. In the case of the mononuclear and trinuclear compounds, additional signals in the visible spectral region are present. In both systems, the origin of these bands is due to charge transfer from ligand to metal and d-d transitions.

  19. In vitro anti-mycobacterial activity of (E)-N'-(monosubstituted-benzylidene) isonicotinohydrazide derivatives against isoniazid-resistant strains

    PubMed Central

    Coelho, Tatiane S.; Cantos, Jessica B.; Bispo, Marcelle L.F.; Gonçalves, Raoni S.B.; Lima, Camilo H.S.; da Silva, Pedro E.A.; Souza, Marcus V. N.

    2012-01-01

    A series of twenty-three N-acylhydrazones derived from isoniazid (INH 1-23) have been evaluated for their in vitro antibacterial activity against INH- susceptible strain of M. tuberculosis (RG500) and three INH-resistant clinical isolates (RG102, RG103 and RG113). In general, derivatives 4, 14, 15 and 16 (MIC=1.92, 1.96, 1.96 and 1.86 µM, respectively) showed relevant activities against RG500 strain, while the derivative 13 (MIC=0.98 µM) was more active than INH (MIC=1.14 µM). However, these derivatives were inactive against RGH102, which displays a mutation in the coding region of inhA. These results suggest that the activities of these compounds depend on the inhibition of this enzyme. However, the possibility of other mechanisms of action cannot be excluded, since compounds 2, 4, 6, 7, 12–17, 19, 21 and 23 showed good activities against katG-resistant strain RGH103, being more than 10-fold more active than INH. PMID:24470920

  20. Dispersion of the linear and nonlinear optical susceptibilities of the CuAl(S{sub 1–x}Se{sub x})₂ mixed chaclcopyrite compounds

    SciTech Connect

    Reshak, A. H.; Brik, M. G.; Auluck, S.

    2014-09-14

    Based on the electronic band structure, we have calculated the dispersion of the linear and nonlinear optical susceptibilities for the mixed CuAl(S{sub 1–x}Se{sub x})₂ chaclcopyrite compounds with x=0.0, 0.25, 0.5, 0.75, and 1.0. Calculations are performed within the Perdew-Becke-Ernzerhof general gradient approximation. The investigated compounds possess a direct band gap of about 2.2 eV (CuAlS₂), 1.9 eV (CuAl(S₀.₇₅Se₀.₂₅)₂), 1.7 eV (CuAl(S₀.₅Se₀.₅)₂), 1.5 eV (CuAl(S₀.₂₅Se₀.₇₅)₂), and 1.4 eV (CuAlSe₂) which tuned to make them optically active for the optoelectronics and photovoltaic applications. These results confirm that substituting S by Se causes significant band gaps' reduction. The optical function's dispersion ε₂{sup xx}(ω) and ε₂{sup zz}(ω)/ε₂{sup xx}(ω), ε₂{sup yy}(ω), and ε₂{sup zz}(ω) was calculated and discussed in detail. To demonstrate the effect of substituting S by Se on the complex second-order nonlinear optical susceptibility tensors, we performed detailed calculations for the complex second-order nonlinear optical susceptibility tensors, which show that the neat parents compounds CuAlS₂ and CuAlSe₂ exhibit | χ₁₂₂²}(-2ω;ω;ω) | as the dominant component, while the mixed alloys exhibit | χ₁₁₁²(-2ω;ω;ω) | as the dominant component. The features of | χ₁₂₃²}(-2ω;ω;ω) | and | χ{sub 111}²}(-2ω;ω;ω) | spectra were analyzed on the basis of the absorptive part of the corresponding dielectric function ε₂(ω) as a function of both ω/2 and ω.

  1. Synthesis and enantioselectivity of optically active 1- and 3-substituted 4-phenyl-1,2,3,4-tetrahydroisoquinolin-4-ols and related compounds as norepinephrine potentiators.

    PubMed

    Kihara, M; Ikeuchi, M; Adachi, S; Nagao, Y; Moritoki, H; Yamaguchi, M; Taira, Z

    1995-09-01

    Optically active 1,2-dimethyl-4-phenyl-1,2,3,4-tetrahydroisoquinolin-4-ols (1R,4R-3a and 1S,4S-3b, 1S,4R-4a, and 1R,4S-4b) and 2-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinolines (4S-5a and 4R-5b) were prepared in order to examine the effects of the 1-, 3-, and 4-substituents of 2-methyl-4-phenyl- 1,2,3,4-tetrahydroisoquinolin-4-ol (PI-OH) (1) on the enantioselectivity for norepinephrine (NE) potentiating activity. The conformations and absolute configurations of 3-5 were determined from their 1H-NMR and circular dichroism (CD) spectra and by single-crystal X-ray diffractometric analysis. The NE potentiating activity of the optically active 3-5 and previously prepared 3-methyl derivatives (3R,4R-6a and 3S,4S-6b) of PI-OH were tested. The results show that compounds 3, 4, and 6 had high enantioselectivity for NE potentiation: the 4R series of the enantiomers exhibited activity but not the 4S-enantiomers. The activity of the 4-desoxy compound 5 also resided exclusively in the 4S-enantiomer. These findings suggest the presence of a specific receptor for NE uptake, and the enantiomers 3a, 4a, 5a, and 6a may be antagonistic at this NE uptake receptor. PMID:7586079

  2. Magnetic, resonance, and optical properties of Cu3Sm (SeO3)2O2Cl : A rare-earth francisite compound

    NASA Astrophysics Data System (ADS)

    Zakharov, K. V.; Zvereva, E. A.; Markina, M. M.; Stratan, M. I.; Kuznetsova, E. S.; Dunaev, S. F.; Berdonosov, P. S.; Dolgikh, V. A.; Olenev, A. V.; Klimin, S. A.; Mazaev, L. S.; Kashchenko, M. A.; Ahmed, Md. A.; Banerjee, A.; Bandyopadhyay, S.; Iqbal, A.; Rahaman, B.; Saha-Dasgupta, T.; Vasiliev, A. N.

    2016-08-01

    In this combined experimental and theoretical paper, we study the properties of Cu3Sm (SeO3)2O2Cl belonging to the francisite family of compounds, which are novel frustrated layered compounds. Cu3Sm (SeO3)2O2Cl is synthesized through a solid state reaction. Characterizations through measurements of magnetization, specific heat, X-band electron spin resonance, and rare-earth optical spectroscopy, establish that the compound orders antiferromagnetically at TN=35 K and undergoes a spin-reorientation phase transition at TC=8.5 K due to the interplay of anisotropies in transition metal and rare-earth subsystems. The ground state Kramers doublet of Sm is found to split only at T

  3. Characterization of the Localized Excited State of Monosubstituted Ruthenium (ii) Complexes, and Thermodynamic and Structural Investigations on Langmuir Monolayers and Built-Up Multilayers.

    NASA Astrophysics Data System (ADS)

    Samuels, Alan Christopher

    This dissertation consists of two parts. The first part is contained in chapter one, which describes an Electron Spin Resonance (ESR) investigation of the metal -ligand charge transfer (MLCT) excited state of monodiimine complexes of ruthenium (II). Specifically, the electrochemically reduced mono-substituted diimine complexes [ {rm Ru(bpy)(CN)}_4]^ {2-}, [{rm Ru(bpm)(CN)}_4]^{2- }, and [{rm Ru(bpz)(CN) }_4]^{2-}, where bpy = 2,2^'-bipyridine, bpm = 2,2^'-bipyrimidine, and bpz = 2,2^'-bipyrazine, were characterized by ESR spectroscopy. Well-resolved hyperfine structure (hfs) was observed in all three complexes, and coupling constants were calculated from the observed spectra. The hyperfine coupling constants derived from the ESR spectra indicate that the electronic spin density is largely localized within the pi* orbitals of the reduced species. Emission spectra, solvatochromic absorption spectra, and cyclic voltammetry data are also presented and discussed. The second part of this dissertation constitutes the remaining chapters, and details a comprehensive series of investigations on a monolayer fatty acid film system prepared by the classical Langmuir technique. Specifically, monolayer and multilayer films composed of mixtures of behenic acid and platinum bis(2-(2-thienyl)-pyridine were prepared by the Langmuir-Blodgett and Langmuir-Schaefer techniques, and characterized by FTIR transmission and reflectance-absorbance spectroscopy, visible dichroism, emission spectroscopy, transmission electron microscopy and electron diffraction. Langmuir film properties were investigated as a function of subphase temperature to elucidate the phase changes observed in the pressure-area isotherms for these mixtures. Chromatographic analysis of phenacyl derivatives of the fatty acids coupled with luminescence measurements on the platinum complex was performed to elucidate the composition and structure of the multilayer films. The results suggest that the platinum complex assumes a

  4. Pressure dependence of the optical properties of the charge-density-wave compound LaTe2

    SciTech Connect

    Lavagnini, M.; Sacchetti, A.; Degiorgi, L.; Arcangeletti, E.; Baldassarre, L.; Postorino, P.; Lupi, S.; Perucchi, A.; Shin, K.Y.; Fisher, I.R.; /Stanford U., Geballe Lab.

    2009-12-14

    We report the pressure dependence of the optical response of LaTe{sub 2}, which is deep in the charge-density-wave (CDW) ground state even at 300 K. The reflectivity spectrum is collected in the mid-infrared spectral range at room temperature and at pressures between 0 and 7 GPa. We extract the energy scale due to the single particle excitation across the CDW gap and the Drude weight. We establish that the gap decreases upon compressing the lattice, while the Drude weight increases. This signals a reduction in the quality of nesting upon applying pressure, therefore inducing a lesser impact of the CDW condensate on the electronic properties of LaTe{sub 2}. The consequent suppression of the CDW gap leads to a release of additional charge carriers, manifested by the shift of weight from the gap feature into the metallic component of the optical response. On the contrary, the power-law behavior, seen in the optical conductivity at energies above the gap excitation and indicating a weakly interacting limit within the Tomonaga-Luttinger liquid scenario, seems to be only moderately dependent on pressure.

  5. a Study of the Structural, Magnetic, Optical, and Electronic Properties of Several New Copper(ii) Halide and Copper(ii, i) Halide Compounds in the Solid State.

    NASA Astrophysics Data System (ADS)

    Scott, Brian Lindley

    The synthesis, x-ray crystal structures, magnetic susceptibilities, and ligand field transition energies are reported for several A_2Cu _2X_6 (A = organic cation; X = Cl, Br) compounds. The structure of the Cu _2Br_6^{2 -} dimer within these solids is correlated to their magnetic exchange and ligand field spectral results; the critical structural parameters tied to these properties are the geometry of the X-Cu-X bridge, and the coordination geometry about the metal centers. Spectral assignments are made in light of EHMO calculations. The synthesis, x-ray structures, and the polarized ligand field and charge transfer absorption results on the two room temperature phases of ((C_3 H_7)_4N) _2Cu_2Br _6 are presented. Striking piezochromic and thermochromic phase transitions are observed between these two phases. The optical properties associated with these phase transitions are explained in terms of a difference in orientation of the Cu_2Br _6^{2-} chromophore within each of the two phases. An absorption band unique to the dimer (not observed in the CuBr_4^ {2-} monomer) is assigned to a ligand to metal charge transfer transition, and not to a simultaneous ligand field transition occurring on each metal center. The synthesis, x-ray structure, absorption spectroscopy, magnetic susceptibility, and electronic conductivity results for a series of mixed-valence Cu(II,I) halide compounds are reported. These compounds fall into the following two categories: a family of pseudo 1-D compounds with the stoichiometry ACu_2X_4 (A = tetraalkylammonium cation, X = Cl, Br), and the compound (hydrazinium)_2Cu _3Cl_6. All of the compounds contain bridges of the type Cu(I)-X-Cu(II). It is shown via absorption spectroscopy and EHMO results that all of these compounds contain intervalence charge transfer bands. The 1-D salts show semiconductive behavior. The physical properties of the 1-D salts are rationalized in terms of band calculations. All compounds are assigned to Class II in the

  6. Detection of volatile organic compounds using optical fibre long period grating modified with metal organic framework thin films

    NASA Astrophysics Data System (ADS)

    Hromadka, Jiri; Tokay, Begum; Korposh, Sergiy; James, Stephen; Tatam, Ralph P.

    2015-09-01

    An optical fibre long period grating (LPG) modified with a thin film of ZIF-8, a zeolitic immidazol framework (ZIF) material, a subgroup of the metal organic framework (MOF) family, was employed for the detection of organic vapours. ZIF-8 film was deposited onto the surface of the LPG using an in-situ crystallization technique. The sensing mechanism is based on the measurement of the refractive index (RI) change induced by the penetration of the chemical molecules into the ZIF-8 pores. An LPG modified with 5 growth cycles of ZIF-8 responded to exposure to methanol and ethanol vapours.

  7. Comparative optical study of the two-dimensional donor-type intercalation compounds graphite-KHx and their binary counterparts C8K and C24K

    NASA Astrophysics Data System (ADS)

    Doll, G. L.; Yang, M. H.; Eklund, P. C.

    1987-06-01

    We report the results of optical reflectivity studies of the stage-1 and -2 graphite-KHx intercalation compounds prepared by direct reaction of highly ordered pyrolytic graphite and KH powder. The stage-1 and -2 binary graphite-K compounds are studied for comparison. The optical data are analyzed in terms of a model involving two-dimensional (2D) graphitic π electrons and three-dimensional (3D) nearly free K(4s) electrons. The model is used to interpret the observed values of the free-carrier unscreened plasma frequencies and the position of the interband absorption threshold to determine experimental values for the Fermi level (EF) in the carbon π band(s) and the fractional occupation of the K(4s) band. For the hydrides, we find quantitative evidence that the hydrogen states lie below EF. Thus, hydrogen is present as H-, acting as an acceptor, thereby compensating the electron donation to the π bands from the K(4s) states. This assumption and the optical data for the stage-1 and -2 hydrides results in a [H]/[K] ratio of 0.8, in excellent agreement with chemical analyses reported by Guérard and co-workers, and leads to very small values for the fractional K(4s) band occupation fK<0.03 electrons per K atom. Within the framework of a superimposed 2D (π) and 3D [K(4s)] rigid-band model, our experimental results support an empty K(4s) band (i.e., fK=0) in stage-2 C24K. In stage-1 C8K, the rigid-band model yields large values for fK (fK>0.5 electrons per K atom), unless the value of the optical mass of the electrons in the K(4s) states is larger than ~2. The C8K results are also discussed in terms of more sophisticated energy-band calculations.

  8. Mn doping effect on optical and ESR studies of Zn1-xMnxO compound sintered at different temperatures

    NASA Astrophysics Data System (ADS)

    Mahule, T.; Srinivasu, V. V.; Das, J.

    2016-05-01

    Polycrystalline bulk samples of Zn1-xMnxO with x=0.02, 0.04, 0.05 and sintered at different temperatures (500 °C & 800 °C) were studied to investigate the doping effect on the structural, optical properties and spin dynamics in ZnO system. The crystallite size was seen to decrease with no significant change in other structural parameters. FTIR study showed a small effect on the Zn-O stretching bond and other bonds due to presence of Mn. Calculation from UV-Vis spectra showed increase in the optical band gap in the low temperature sintered samples due to Mn doping. In the PL spectra, the UV emission seen to dominate for the 500 °C sintered sample, for 800 °C sample the visible emission dominate indicating increase in non-radiative emission. ESR signals obtained from the microwave absorption shows ferromagnetic signal for the low temperature sintered sample only with a g value of 2.004 for the 2% Mn doped sample. The number of spin participation for resonance is calculated from the ESR signal, which supports the magnetic behaviour of this particular sample.

  9. Structural, mechanical, electronic, optical properties and effective masses of CuMO2 (M = Sc, Y, La) compounds: First-principles calculations

    NASA Astrophysics Data System (ADS)

    Liu, Qi-Jun; Zhang, Ning-Chao; Sun, Yan-Yun; Liu, Fu-Sheng; Liu, Zheng-Tang

    2014-05-01

    The structural, elastic, mechanical, electronic, optical properties and effective masses of CuMIIIBO2 (MIIIB = Sc, Y, La) compounds have been investigated by the plane-wave ultrasoft pseudopotential technique based on the first-principles density-functional theory under local density approximation. The equilibrium structural parameters are in good agreement with previous experimental and theoretical data. To our knowledge, there are no available data of elastic constants for comparison. The bulk, shear and Young's modulus, ratio of B/G, Poisson's ratio and Lamé's constants of CuMIIIBO2 have been studied. The electronic structures of CuMIIIBO2 are consistent with other calculations. The population analysis, charge densities and effective masses have been shown and analyzed. The imaginary and real parts of the dielectric function, refractive index and extinction coefficient of CuMIIIBO2 are calculated. The interband transitions to absorption of CuMIIIBO2 have been analyzed.

  10. Detection of volatile organic compounds through a sensing film of TiO II doped with organic dyes deposited on an optical fiber

    NASA Astrophysics Data System (ADS)

    Muñoz A., S.; Ramos M., J.; Martínez H., C.; Castillo M., J.; Beltrán P., G.; Palomino M., R.

    2007-03-01

    The necessity of detection and recognition of different types of gases, such as volatile organic compounds, which are frequently found in food and beverage industries among others, requires the development of different types of sensors. In this work, an application of optical fiber for the detection of volatile organic compounds, particularly ethanol is presented. The sensor was constructed removing a portion of the cladding and depositing instead a sensing titanium dioxide (TiO II) film doped with an organic dye (rhodamine 6G) by the sol-gel method. The sensor response was measured in a Teflon chamber where the sample to be measured was injected. A He-Ne laser beam was coupled to the fiber and the variation in the output power was measured which indicates the gas presence. The difference between the output power with and without gas gives a measure of the concentration that exists in the chamber. The experimental results showed that for an ethanol concentration range from 0 to 10500 ppm, the response of the sensor was approximately linear with a correlation coefficient of 0.9924.

  11. Electronic and optical properties of novel carbazole-based donor-acceptor compounds for applications in blue-emitting organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Legaspi, Christian M.; Stubbs, Regan E.; Yaron, David J.; Peteanu, Linda A.; Sfeir, Matthew Y.; Kemboi, Abraham; Picker, Jesse; Fossum, Eric

    2015-08-01

    Organic light-emitting diodes (OLEDs) have received a significant attention over the past decade due to their energy-saving potential. We have recently synthesized two novel carbazole-based donor-acceptor compounds and analyzed their optical properties to determine their suitability for use as blue emitters in OLEDs. These compounds show remarkable photo-stability and high quantum yields in the blue region of the spectrum. In addition, they have highly solvatochromic emission. In non-polar solvents, bright, blue-shifted (λmax ≈ 398 nm), and highly structured emission is seen. With increasing solvent dielectric constant, the emission becomes weaker, red-shifted (λmax ≈ 507 nm), and broad. We aim to determine the underlying cause of these changes. Electronic structure calculations indicate the presence of multiple excited states with comparable oscillator strength. These states are of interest because there are several with charge-transfer (CT) character, and others centered on the donor moiety. We theorize that CT states play a role in the observed changes in emission lineshape and may promote charge mobility for electrofluorescence in OLEDs. In the future, we plan to use Stark spectroscopy to analyze the polarity of excited states and transient absorption spectroscopy to observe the dynamics in the excited state.

  12. Confocal Raman microscopy of pH-gradient-based 10 000-fold preconcentration of compounds within individual, optically trapped phospholipid vesicles.

    PubMed

    Myers, Grant A; Harris, Joel M

    2011-08-01

    A stable pH gradient established across the membrane of phospholipid vesicle can induce the accumulation of ionizable compounds from bulk solution into the vesicle interior. This pH-gradient vesicle loading process has previously been utilized to encapsulate drugs in pharmaceutical liposomal formulations. In the present work, this process is exploited to preconcentrate dilute analytes from free solution into phospholipid vesicles, which are then detected by optically trapping individual vesicles and measuring their contents using confocal Raman microscopy. The theory of accumulation, based on the acid-base ionization equilibria of the analyte, is developed to account for depletion of the source phase and the finite buffering capacity of the vesicle interior. The model predicts that, under appropriate conditions, enrichment factors of more than 4 orders of magnitude can be realized. To test the concept, experiments were performed measuring the accumulation of benzyldimethylamine into 600-nm phospholipid vesicles. Manipulation of vesicles by optical trapping allows accumulation within an individual vesicle to be characterized while varying the external solution conditions. A more than 10 000-fold enrichment of the analyte concentration inside the vesicle relative to the source phase is reported. The results suggest that pH-gradient loading could be exploited as a powerful preconcentration scheme for trace analysis using either Raman microscopy or other microspectroscopy techniques. PMID:21740010

  13. Gas Sensor Using a Rhodamine-6 G Doped TiO2 Film Deposited on an Optical Fiber to Detect Volatile Organic Compounds.

    NASA Astrophysics Data System (ADS)

    Aguirre, S. Muñoz; Hipatl, C. Martínez; Mixcóatl, J. Castillo; Pérez, G. Beltrán; Merino, R. Palomino

    2008-04-01

    The necessity of detection and recognition of different types of gases, such as simple volatile organic compounds or their mixtures, requires the development of different types of sensors and the study of different materials for sensing films. In this work, an application of an optical fiber to the detection of VOC is presented. The sensor was constructed removing a portion of the cladding of approximately 3 cm and depositing instead a sensing titanium dioxide (TiO2) film doped with an organic dye (rhodamine 6 G) by the sol-gel technique. The sensor operation principle is based on the absorption of evanescent wave when the sensing film interacts with the VOC molecules, which attenuates the output optical power. The difference between the output power with and without gas gives a measure of the concentration in the chamber. The results showed that for ethanol concentration from 0 to 10,000 ppm, the response of the sensor was approximately linear. The sensor responses to octane and ethyl acetate were also studied.

  14. First principles study of hydrogen storage material NaBH4 and LiAlH4 compounds: electronic structure and optical properties

    NASA Astrophysics Data System (ADS)

    Ghellab, T.; Charifi, Z.; Baaziz, H.; Uğur, Ş.; Uğur, G.; Soyalp, F.

    2016-04-01

    A comprehensive study of structure, phase stability, optical and electronic properties of LiAlH4 and NaBH4 light-metal hydrides is presented. The calculations are carried out within density functional theory using the full potential linear augmented plane wave method. The exchange-correlation potential is treated within the local density approximation and the generalized gradient approximation (GGA) to calculate the total energy. Furthermore, the Engel-Vosko GGA approach is employed to compute electronic and optical properties such as reflectivity spectra. The phases α, β and γ of LiAlH4 and NaBH4 hydrides are investigated, the phase transition from the β to the high-pressure γ phase is determined for NaBH4 and is accompanied by a 1% volume decrease. For LiAlH4, no phase transition is detected. The materials under consideration are classified as wide band gap compounds. From the analysis of the structures at different phases, it is deduced that the hydrides show strong covalent interaction between B (Al) and H in the [BH4]- ([AlH4]-) anions and ionic bonding character between [BH4]- and Na+ for NaBH4, and [AlH4]- and Li+ for LiAlH4. The complex dielectric function, absorption coefficient and the reflectivity spectra are also computed and analyzed in different phases.

  15. First-principles studies of the structural, electronic, and optical properties of a novel thorium compound Rb{sub 2}Th{sub 7}Se{sub 15}

    SciTech Connect

    Brik, M.G.

    2014-04-01

    The structural, electronic, and optical properties of a recently synthesized thorium compound Rb{sub 2}Th{sub 7}Se{sub 15} have been calculated in the density functional theory framework for the first time. The calculated direct band gap was 1.471 eV (generalized gradient approximation) and 1.171 eV (local density approximation), with both results being close to the experimental result of 1.83 eV. High covalency/iconicity of the Th–Se/Rb–Se bonds was demonstrated by calculating effective Mulliken charges of all ions. The polarized calculations of the complex dielectric function are presented; dependence of the calculated index of refraction was fitted to the Sellmeyer equation in the wavelength range from 500 to 2500 nm. - Graphical abstract: Calculated band structure of Rb{sub 2}Th{sub 7}Se{sub 15}. - Highlights: • The first theoretical analysis of the Rb{sub 2}Th{sub 7}Se{sub 15} properties is reported. • Structural, electronic and optical properties of Rb{sub 2}Th{sub 7}Se{sub 15} were calculated. • An indirect character of Rb{sub 2}Th{sub 7}Se{sub 15} band gap was confirmed. • Dependence of the refractive index on the wavelength was calculated.

  16. Electronic and optical properties of the LiCdX (X = N, P, As and Sb) filled-tetrahedral compounds with the Tran–Blaha modified Becke–Johnson density functional

    SciTech Connect

    Bouhemadou, A.; Bin-Omran, S.; Allali, D.; Al-Otaibi, S.M.; Khenata, R.; Al-Douri, Y.; Chegaar, M.; Reshak, A.H.

    2015-04-15

    Highlights: • Electronic and optical properties of the LiCdX compounds have been predicted. • Tran–Blaha-modified Becke–Johnson functional significantly improves the band gap. • We predict a direct band gap in all of the considered LiCdX compounds. • Origin of the peaks in the optical spectra is determined. - Abstract: The structural, electronic and optical properties of the LiCdN, LiCdP, LiCdAs and LiCdSb filled-tetrahedral compounds have been explored from first-principles. The calculated structural parameters are consistent with the available experimental results. Since DFT with the common LDA and GGA underestimates the band gap, we use a new developed functional able to accurately describe the electronic structure of semiconductors, namely the Tran–Blaha-modified Becke–Johnson potential. The four investigated compounds demonstrate semiconducting behavior with direct band gap ranging from about 0.32 to 1.65 eV. The charge-carrier effective masses are evaluated at the topmost valence band and at the bottommost conduction band. The evolution of the value and nature of the energy band gap under pressure effect is also investigated. The frequency-dependent complex dielectric function and some macroscopic optical constants are estimated. The microscopic origins of the structures in the optical spectra are determined in terms of the calculated energy band structures.

  17. Compound semiconductor native oxide-based technologies for optical and electrical devices grown on gallium arsenide substrates using MOCVD

    NASA Astrophysics Data System (ADS)

    Holmes, Adrian Lawrence

    1999-11-01

    The beginning of the modern microelectronics industry can be traced back to an invention made in 1947 when Bardeen and Brattain created the first semiconductor switch, called a transistor. Several other important discoveries followed; however, two of the more significant were (i) the development of the first planar process using silicon dioxide (SiO2) as a mask for diffusions into silicon by Frosch in 1955, and (ii) the subsequent integration of several transistors in tiny circuits by Kilby in 1958. Due to the superior quality of the SiO2-silicon interface, Si-based metal-oxide-semiconductor (MOS) transistors have primarily been used in integrated circuits. Until recently, compound semiconductors did not have a native oxide of sufficient quality to create similar MOS transistors. In 1990, research performed by Professor Holonyak and his group at the University of Illinois at Urbana-Champaign has led to a high-quality, stable, and insulating native oxide created from aluminum-containing compound semiconductor alloys. This study investigates native oxide films that are formed by the thermal oxidation of AlAs and InAlP epitaxial layers grown lattice-matched on GaAs substrates using metalorganic chemical vapor deposition (MOCVD). The primary goal is to evaluate how these native oxides can help form novel device structures and transistors. To qualify the material properties of these native oxide films, we have used several characterization techniques including photoluminescence, cross-sectional scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Additionally, we have performed leakage current and capacitance-voltage measurements to evaluate the electrical characteristics of the native oxide-semiconductor interface. The kinetics of the thermal oxidation process for both the surface oxidation of InAlP and lateral oxidation of AlAs are studied and contrasted. Aided by this knowledge, we have created a sealed

  18. Green synthesis of CuO nanoparticles by aqueous extract of Gundelia tournefortii and evaluation of their catalytic activity for the synthesis of N-monosubstituted ureas and reduction of 4-nitrophenol.

    PubMed

    Nasrollahzadeh, Mahmoud; Maham, Mehdi; Sajadi, S Mohammad

    2015-10-01

    A facile, efficient and environmentally-friendly protocol has been developed for the green synthesis of CuO nanoparticles (NPs) by aqueous extract of Gundelia tournefortii as a mild, renewable and non-toxic reducing agent. CuO NPs were characterized by SEM, TEM, XRD, EDS, FT-IR and UV-vis spectroscopy. More importantly, the green synthesized CuO NPs presented excellent catalytic activity for reduction of 4-nitrophenol and synthesis of N-monosubstituted ureas via hydration of cyanamides with the aid of acetaldoxime as an effective water surrogate in ethanol as a green solvent. The catalyst was easily separated and the recovered catalyst was reused many times without any significant loss of the catalytic activity. PMID:26073846

  19. Fiber optic NIR evanescent wave absorption sensor systems for in-situ monitoring of hydrocarbon compounds in waste and ground water

    NASA Astrophysics Data System (ADS)

    Buerck, Jochen; Denter, P.; Mensch, M.; Kraemer, K.; Scholz, Michael

    1999-02-01

    In situ measurements with the prototype of a portable fiber- optic sensor system for the monitoring of nonpolar hydrocarbons (HC) in ground water or industrial waste water are presented. This sensor system can be used for quantitative in situ analysis of pollutants such as aromatic solvents, fuels, mineral oils or chlorinated HCs in a broad concentration range from around 200 (mu) g(DOT) L-1 up to a few 100 mg(DOT) L-1. The sensing principle is based on solid phase extraction of analyte molecules into a hydrophobic silicone cladding of a quartz glass optical fiber and the direct absorptiometric measurement of the extracted species in the polymer through the evanescent wave. The sensor can be connected via all-silica fibers with a length of up to 100 m to a filter photometer developed at the IFIA, thus allowing even remote analysis in monitoring wells. This instrument provides a sum concentration signal of the extracted organic compounds by measuring the integral absorption at the C-H overtone bands in the near-infrared spectral range. In situ measurements with the sensor system were performed in a ground water circulation well at the VEGAS research facility (Universitat Stuttgart). Here, the sensor proved to trace the HC sum concentration of xylene isomers in process water pumped from the well to a stripper column. In further experiments the sensor was combined with an oil sampling device and was tested with simulated waste waters of a commercial vehicle plant contaminated with different types of mineral oil. In this case the sensor system was able to detect the presence of mineral oil films floating on water or oil-in-water emulsions with concentrations greater than 20 ppm (v/v) within a few minutes.

  20. Exploring the electronic structure and optical properties of the quaternary selenide compound, Ba{sub 4}Ga{sub 4}SnSe{sub 12}: For photovoltaic applications

    SciTech Connect

    Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya

    2015-09-15

    Due to huge demand on discovering new materials for energy, we used first-principle calculations to explore the electronic structure and optical properties of a recent quaternary selenide, namely Ba{sub 4}Ga{sub 4}SnSe{sub 12}. The electronic structure and the optical properties of Ba{sub 4}Ga{sub 4}SnSe{sub 12} were calculated through a reliable approach of Engle Vosko-GGA (EV-GGA). We found that Ba{sub 4}Ga{sub 4}SnSe{sub 12} has a direct band gap of 2.14 eV positioned at Γ. Acquiring the fundamental characteristics of Ba{sub 4}Ga{sub 4}SnSe{sub 12,} we studied the linear optical properties like dielectric function in the energy range of 0–14 eV. From the dielectric function we noticed a weak directional anisotropy for the two components. The absorption spectrum indicates the possibility of greater multiple direct and indirect inter-band transitions in the visible regions and shows similar behavior with experimental spectrum. Ba{sub 4}Ga{sub 4}SnSe{sub 12} can be used as shielding material from UV radiations. Present study predicts that the Ba{sub 4}Ga{sub 4}SnSe{sub 12} is promising for photovoltaic applications due to their high absorption of solar radiations and photoconductivity in the visible range. - Graphical abstract: Interesting quaternary selenide compound, Ba{sub 4}Ga{sub 4}SnSe{sub 12}, for photovoltaic applications. - Highlights: • Ba{sub 4}Ga{sub 4}SnSe{sub 12} is a quaternary selenide designed for PV and thermoelectric. • Ba{sub 4}Ga{sub 4}SnSe{sub 12} has a direct band gap of 2.14 eV. • Ba{sub 4}Ga{sub 4}SnSe{sub 12,} has a maximum reflectivity in the visible and UV regions.

  1. Investigation of p-side contact layers for II-VI compound semiconductor optical devices fabricated on InP substrates by MBE

    NASA Astrophysics Data System (ADS)

    Takamatsu, Shingo; Nomura, Ichirou; Shiraishi, Tomohiro; Kishino, Katsumi

    2015-09-01

    N-doped p-type ZnTe and ZnSeTe contact layers were investigated to evaluate which is more suitable for use in II-VI compound semiconductor optical devices on InP substrates. Contact resistances (Rc) between the contact layers and several electrode materials (Pd/Pt/Au, Pd/Au, and Au) were measured by the circular transmission line model (c-TLM) method using p-n diode samples grown on InP substrates by molecular beam epitaxy (MBE). The lowest Rc (6.5×10-5 Ω cm2) was obtained in the case of the ZnTe contact and Pd/Pt/Au electrode combination, which proves that the combination is suitable for obtaining low Rc. Yellow light-emitting diode devices with a ZnTe and ZnSeTe p-contact layer were fabricated by MBE to investigate the effect of different contact layers. The devices were characterized under direct current injections at room temperature. Yellow emission at around 600 nm was observed for each device. Higher emission intensity and lower slope resistance were obtained for the device with the ZnTe contact layer and Pd/Pt/Au electrode compared with other devices. These device performances are ascribed to the low Rc of the ZnTe contact and Pd/Pt/Au electrode combination.

  2. Electrical induction and optical erasure of birefringence in the isotropic liquid phase of a dichiral azobenzene liquid-crystalline compound (Presentation Recording)

    NASA Astrophysics Data System (ADS)

    Yamamoto, Takahiro; Nishiyama, Isa

    2015-10-01

    Liquid crystal is a representative soft matter, which has physical properties between those of conventional liquid and those of crystal in a temperature range above a melting point. A liquid-crystal display (LCD) employs the response of the liquid-crystal alignment to the electric field and is a key device of an information display. For common LCDs, the precise control of the initial alignment of LC molecules is needed so that a good dark state, thus a high contrast ratio, can be obtained. If the birefringence can be induced in the liquid phase by the application of electric field, it is of great use as a material for the LCD application. In this study, we will report a unique property of dichiral azobenzene liquid crystals: an electric induction of birefringence in a liquid phase of an antiferroelectric dichiral azobenzene liquid crystal. The optically isotropic texture changes into the homogenous birefringent texture by the application of the in-plane electric field above the clearing temperature of the liquid crystal. We find that one of the possible reasons of the induction of the birefringence in the isotropic phase is the electrically-induced increase of the phase transition temperature between the antiferroelectric liquid-crystalline and "liquid" phases, i.e., increase in the clearing temperature. The resulting birefringence can be disappeared by the irradiation of UV light, due to the photoinduced isomerization of the azobenzene compound, thus dual control of the birefringent structure, by the irradiation of light and/or by the application of the electric field, is achieved.

  3. Real-time imaging of RGC death with a cell-impermeable nucleic acid dyeing compound after optic nerve crush in a murine model.

    PubMed

    Tsuda, Satoru; Tanaka, Yuji; Kunikata, Hiroshi; Yokoyama, Yu; Yasuda, Masayuki; Ito, Azusa; Nakazawa, Toru

    2016-05-01

    The retinal ganglion cells (RGCs) are the main source of therapeutic targets for neuroprotective glaucoma treatment, and evaluating RGCs is key for effective glaucoma care. Thus, we developed a minimally invasive, quick, real-time method to evaluate RGC death in mice. In this article we describe the details of our method, report new results obtained from C57BL/6J mice, and report that our method was usable in wild type (WT) and knockout (KO) mice lacking an RGC-death-suppressing gene. It used a non-invasive confocal scanning laser ophthalmoscope (cSLO) and a low molecular weight, photo-switching, cell-impermeant, fluorescent nucleic acid dyeing compound, SYTOX orange (SO). The RGCs were retrogradely labeled with Fluorogold (FG), the optic nerve was crushed (ONC), and SO was injected into the vitreous. After ten minutes, RGC death was visualized with cSLO in vivo. The retinas were then extracted and flat mounted for histological observation. SO-labeled RGCs were counted in vivo and FG-labeled RGCs were counted in retinal flat mounts. The time course of RGC death was examined in Calpastatin KO mice and wild type (WT) mice. Our in vivo imaging method revealed that SO-positive dead RGCs were mainly present from 4 to 6 days after ONC, and the peak of RGC death was after 5 days. Moreover, the number of SO-positive dead RGCs after 5 days differed significantly in the Calpastatin KO mice and the WT mice. Counting FG-labeled RGCs in isolated retinas confirmed these results. Thus, real-time imaging with SO was able to quickly quantify ONC-induced RGC death. This technique may aid research into RGC death and the development of new neuroprotective therapies for glaucoma. PMID:27013099

  4. Organotin compounds in precipitation, fog and soils of a forested ecosystem in Germany.

    PubMed

    Huang, Jen-How; Schwesig, David; Matzner, Egbert

    2004-07-01

    Organotin compounds (OTC) are highly toxic pollutants and have been mostly investigated so far in aquatic systems and sediments. The concentrations and fluxes of different organotin compounds, including methyl-, butyl-, and octyltin species in precipitation and fog were investigated in a forested catchment in NE Bavaria, Germany. Contents, along with the vertical distribution and storages in two upland and two wetland soils were determined. During the 1-year monitoring, the OTC concentrations in bulk deposition, throughfall and fog ranged from 1 ng Sn l(-1) to several ten ng Sn l(-1), but never over 200 ng Sn l(-1). The OTC concentrations in fog were generally higher than in throughfall and bulk deposition. Mono-substituted species were the dominant Sn species in precipitation (up to 190 ng Sn l(-1)) equaling a flux of up to 70 mg Sn ha(-1) a(-1). In upland soils, OTC contents peaked in the forest floor (up to 30 ng Sn g(-1)) and decreased sharply with the depth. In wetland soils, OTC had slightly higher contents in the upper horizons. The dominance of mono-substituted species in precipitation is well reflected in the contents and storages of OTC in both upland and wetland soils. The ratios of OTC soil storages to the annual throughfall flux ranged from 20 to 600 years. These high ratios are probably due to high stability and low mobility of OTC in soils. No evidence was found for methylation of tin in the wetland soils. In comparison with sediments, concentrations and contents of organotin in forest soils are considerably lower, and the dominant species are less toxic. It is concluded that forested soils may act as sinks for OTC deposited from the atmosphere. PMID:15158032

  5. Anaerobic biodegradation of phenolic compounds in digested sludge.

    PubMed Central

    Boyd, S A; Shelton, D R; Berry, D; Tiedje, J M

    1983-01-01

    We examined the anaerobic degradation of phenol and the ortho, meta, and para isomers of chlorophenol, methoxyphenol, methylphenol (cresol), and nitrophenol in anaerobic sewage sludge diluted to 10% in a mineral salts medium. Of the 12 monosubstituted phenols studied, only p-chlorophenol and o-cresol were not significantly degraded during an 8-week incubation period. The phenol compounds degraded and the time required for complete substrate disappearance (in weeks) were: phenol (2), o-chlorophenol (3), m-chlorophenol (7), o-methoxyphenol (2), m- and p-methoxyphenol (1), m-cresol (7), p-cresol (3), and o-, m-, and p-nitrophenol (1). Complete mineralization of phenol, o-chlorophenol, m-cresol, p-cresol, o-nitrophenol, p-nitrophenol, and o-, m-, and p-methoxyphenol was observed. In general, the presence of Cl and NO2 groups on phenols inhibited methane production. Elimination or transformation of these substituents was accompanied by increased methane production, o-Chlorophenol was metabolized to phenol, which indicated that dechlorination was the initial degradation step. The methoxyphenols were transformed to the corresponding dihydroxybenzene compounds, which were subsequently mineralized. PMID:6614908

  6. Recombinant polycistronic structure of hydantoinase process genes in Escherichia coli for the production of optically pure D-amino acids.

    PubMed

    Martínez-Gómez, Ana Isabel; Martínez-Rodríguez, Sergio; Clemente-Jiménez, Josefa María; Pozo-Dengra, Joaquín; Rodríguez-Vico, Felipe; Las Heras-Vázquez, Francisco Javier

    2007-03-01

    Two recombinant reaction systems for the production of optically pure D-amino acids from different D,L-5-monosubstituted hydantoins were constructed. Each system contained three enzymes, two of which were D-hydantoinase and D-carbamoylase from Agrobacterium tumefaciens BQL9. The third enzyme was hydantoin racemase 1 for the first system and hydantoin racemase 2 for the second system, both from A. tumefaciens C58. Each system was formed by using a recombinant Escherichia coli strain with one plasmid harboring three genes coexpressed with one promoter in a polycistronic structure. The D-carbamoylase gene was cloned closest to the promoter in order to obtain the highest level of synthesis of the enzyme, thus avoiding intermediate accumulation, which decreases the reaction rate. Both systems were able to produce 100% conversion and 100% optically pure D-methionine, D-leucine, D-norleucine, D-norvaline, D-aminobutyric acid, D-valine, D-phenylalanine, D-tyrosine, and D-tryptophan from the corresponding hydantoin racemic mixture. For the production of almost all D-amino acids studied in this work, system 1 hydrolyzed the 5-monosubstituted hydantoins faster than system 2. PMID:17220246

  7. Optical NOR gate

    DOEpatents

    Skogen, Erik J.; Tauke-Pedretti, Anna

    2011-09-06

    An optical NOR gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical NOR gate utilizes two digital optical inputs and a continuous light input to provide a NOR function digital optical output. The optical NOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  8. Optical XOR gate

    SciTech Connect

    Vawter, G. Allen

    2013-11-12

    An optical XOR gate is formed as a photonic integrated circuit (PIC) from two sets of optical waveguide devices on a substrate, with each set of the optical waveguide devices including an electroabsorption modulator electrically connected in series with a waveguide photodetector. The optical XOR gate utilizes two digital optical inputs to generate an XOR function digital optical output. The optical XOR gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  9. Optical data latch

    SciTech Connect

    Vawter, G. Allen

    2010-08-31

    An optical data latch is formed on a substrate from a pair of optical logic gates in a cross-coupled arrangement in which optical waveguides are used to couple an output of each gate to an photodetector input of the other gate. This provides an optical bi-stability which can be used to store a bit of optical information in the latch. Each optical logic gate, which can be an optical NOT gate (i.e. an optical inverter) or an optical NOR gate, includes a waveguide photodetector electrically connected in series with a waveguide electroabsorption modulator. The optical data latch can be formed on a III-V compound semiconductor substrate (e.g. an InP or GaAs substrate) from III-V compound semiconductor layers. A number of optical data latches can be cascaded to form a clocked optical data shift register.

  10. Synthesis, structure, and optical properties of the quaternary diamond-like compounds I{sub 2}–II–IV–VI{sub 4} (I=Cu; II=Mg; IV=Si, Ge; VI=S, Se)

    SciTech Connect

    Liu, Bin-Wen; Zhang, Ming-Jian; Zhao, Zhong-Yan; Zeng, Hui-Yi Zheng, Fa-Kun; Guo, Guo-Cong Huang, Jin-Shun

    2013-08-15

    Three new diamond-like compounds with the formula of I{sub 2}−II−IV−VI{sub 4} (I=Cu; II=Mg; IV=Si, Ge; VI=S, Se) have been synthesized via traditional high-temperature solid-state reactions and structurally characterized by single crystal X-ray diffraction analysis. All the three compounds crystallize in the space group Pmn2{sub 1} in the wurtzite-type superstructure with a=7.563(4), b=6.448(3), c=6.179(3) Å, Z=2 for Cu{sub 2}MgSiS{sub 4} (1); a=7.953(5), b=6.797(4), c=6.507(4) Å, Z=2 for Cu{sub 2}MgGeS{sub 4} (2); a=7.638(4), b=6.515(4), c=6.225(3) Å, Z=2 for Cu{sub 2}MgSiSe{sub 4} (3). All atoms in these compounds are tetrahedrally coordinated. Optical diffuse reflectance UV/Vis/NIR spectra indicate that compounds 1 and 2 have the band gaps of 3.20 and 2.36 eV, respectively. Electronic structure calculations using the CASTEP code indicate that they are all direct band gap compounds. - Graphical abstract: Three new diamond-like compounds, Cu{sub 2}MgSiS{sub 4}, Cu{sub 2}MgGeS{sub 4}, and Cu{sub 2}MgSiSe{sub 4}, have been synthesized. All the three compounds crystallize in the space group Pmn2{sub 1} and all atoms are tetrahedrally coordinated. Highlights: • Three new diamond-like compounds Cu{sub 2}MgSiS{sub 4}, Cu{sub 2}MgGeS{sub 4} and Cu{sub 2}MgSiSe{sub 4} have been synthesized. • All ions are tetrahedrally coordinated. • Electronic structure calculations indicate that they are all direct band gap compounds.

  11. C-C bond unsaturation degree in monosubstituted ferrocenes for molecular electronics investigated by a combined near-edge x-ray absorption fine structure, x-ray photoemission spectroscopy, and density functional theory approach

    SciTech Connect

    Boccia, A.; Lanzilotto, V.; Marrani, A. G.; Zanoni, R.; Stranges, S.; Alagia, M.; Fronzoni, G.; Decleva, P.

    2012-04-07

    We present the results of an experimental and theoretical investigation of monosubstituted ethyl-, vinyl-, and ethynyl-ferrocene (EtFC, VFC, and EFC) free molecules, obtained by means of synchrotron-radiation based C 1s photoabsorption (NEXAFS) and photoemission (C 1s XPS) spectroscopies, and density functional theory (DFT) calculations. Such a combined study is aimed at elucidating the role played by the C-C bond unsaturation degree of the substituent on the electronic structure of the ferrocene derivatives. Such substituents are required for molecular chemical anchoring onto relevant surfaces when ferrocenes are used for molecular electronics hybrid devices. The high resolution C 1s NEXAFS spectra exhibit distinctive features that depend on the degree of unsaturation of the hydrocarbon substituent. The theoretical approach to consider the NEXAFS spectrum made of three parts allowed to disentangle the specific contribution of the substituent group to the experimental spectrum as a function of its unsaturation degree. C 1s IEs were derived from the experimental data analysis based on the DFT calculated IE values for the different carbon atoms of the substituent and cyclopentadienyl (Cp) rings. Distinctive trends of chemical shifts were observed for the substituent carbon atoms and the substituted atom of the Cp ring along the series of ferrocenes. The calculated IE pattern was rationalized in terms of initial and final state effects influencing the IE value, with special regard to the different mechanism of electron conjugation between the Cp ring and the substituent, namely the {sigma}/{pi} hyperconjugation in EtFC and the {pi}-conjugation in VFC and EFC.

  12. C-C bond unsaturation degree in monosubstituted ferrocenes for molecular electronics investigated by a combined near-edge x-ray absorption fine structure, x-ray photoemission spectroscopy, and density functional theory approach

    NASA Astrophysics Data System (ADS)

    Boccia, A.; Lanzilotto, V.; Marrani, A. G.; Stranges, S.; Zanoni, R.; Alagia, M.; Fronzoni, G.; Decleva, P.

    2012-04-01

    We present the results of an experimental and theoretical investigation of monosubstituted ethyl-, vinyl-, and ethynyl-ferrocene (EtFC, VFC, and EFC) free molecules, obtained by means of synchrotron-radiation based C 1s photoabsorption (NEXAFS) and photoemission (C 1s XPS) spectroscopies, and density functional theory (DFT) calculations. Such a combined study is aimed at elucidating the role played by the C-C bond unsaturation degree of the substituent on the electronic structure of the ferrocene derivatives. Such substituents are required for molecular chemical anchoring onto relevant surfaces when ferrocenes are used for molecular electronics hybrid devices. The high resolution C 1s NEXAFS spectra exhibit distinctive features that depend on the degree of unsaturation of the hydrocarbon substituent. The theoretical approach to consider the NEXAFS spectrum made of three parts allowed to disentangle the specific contribution of the substituent group to the experimental spectrum as a function of its unsaturation degree. C 1s IEs were derived from the experimental data analysis based on the DFT calculated IE values for the different carbon atoms of the substituent and cyclopentadienyl (Cp) rings. Distinctive trends of chemical shifts were observed for the substituent carbon atoms and the substituted atom of the Cp ring along the series of ferrocenes. The calculated IE pattern was rationalized in terms of initial and final state effects influencing the IE value, with special regard to the different mechanism of electron conjugation between the Cp ring and the substituent, namely the σ/π hyperconjugation in EtFC and the π-conjugation in VFC and EFC.

  13. Chalcogenide chemistry in ionic liquids: nonlinear optical wave-mixing properties of the double-cubane compound [Sb{sub 7}S{sub 8}Br{sub 2}](AlCl{sub 4}){sub 3}.

    SciTech Connect

    Zhang, Q.; Chung, I.; Jang, J. I.; Ketterson, J. B.; Kanatzidis, M. G.

    2009-07-06

    The new cation [Sb{sub 7}S{sub 8}Br{sub 2}]{sup 3+} has a double-cubane structure and forms as the [AlCl{sub 4}]{sup -} salt from the ionic liquid EMIMBr-AlCl{sub 3} (EMIM = 1-ethyl-3-methylimidazolium) at 165 C. The compound is noncentrosymmetric with space group P2{sub 1}2{sub 1}2{sub 1} and exhibits second-harmonic and difference-frequency nonlinear optical response across a wide range of the visible and near-infrared regions.

  14. Optical NAND gate

    DOEpatents

    Skogen, Erik J.; Raring, James; Tauke-Pedretti, Anna

    2011-08-09

    An optical NAND gate is formed from two pair of optical waveguide devices on a substrate, with each pair of the optical waveguide devices consisting of an electroabsorption modulator and a photodetector. One pair of the optical waveguide devices is electrically connected in parallel to operate as an optical AND gate; and the other pair of the optical waveguide devices is connected in series to operate as an optical NOT gate (i.e. an optical inverter). The optical NAND gate utilizes two digital optical inputs and a continuous light input to provide a NAND function output. The optical NAND gate can be formed from III-V compound semiconductor layers which are epitaxially deposited on a III-V compound semiconductor substrate, and operates at a wavelength in the range of 0.8-2.0 .mu.m.

  15. Compound lens

    DOEpatents

    Brixner, B.B.; Klein, M.M.; Winkler, M.A.

    1980-05-21

    The disclosure relates to at least one calcium fluoride optical element used in combination with at least two ordinary crown glass lens elements to greatly reduce secondary spectrum in optical systems.

  16. Compound lens

    DOEpatents

    Brixner, Berlyn B.; Klein, Morris M.; Winkler, Max A.

    1982-01-01

    The disclosure relates to at least one calcium fluoride optical element used in combination with at least two ordinary crown glass lens elements to greatly reduce secondary spectrum in optical systems.

  17. Ion-forming processes on 248 NM laser excitation of uracil and methyl-monosubstituted uracils: A time-resolved transient conductivity study in aqueous solution

    NASA Astrophysics Data System (ADS)

    Görner, Helmut; Schulte-Frohlinde, Dietrich

    1995-04-01

    Uracil, thymine and 1-, 3-, and 6-methyluracil were studied by time-resolved optical and conductometric methods after 248 nm excitation with 20 ns laser pulses. The transient conductivity in argon-saturated aqueous solution, showing a maximum increase ( Δκmax) during the pulse, is ascribed to the generation of hydrated electrons (e aq-) and protons. Biphotonic photoionization as the primary process is inferred from the almost linear dependence of Δκmax on the square of the laser pulse intensity ( IL2). The quantum yield, obtained from either Δκmax or optical detection of e aq-, e.g. gfe- = 0.02 for uracil at pH 7 and IL = 12 MW cm -2, varies by a factor of about two for the five pyrimidines. The neutralization kinetics depend strongly on pH and the concentrations of laser-induced e aq- and H +, i.e. on IL. At pH 6-7 the Δκ signal decays by second-order kinetics. Under argon the electron adds to the (methyl)uracil and neutralization occurs by reaction of the radical anion with a proton, which originates from a fast decay of the radical cation. Virtually the same conductivity pattern was found for the neutralization reaction of OH - and H + under N 2O. In the acidic pH range the decay changes to first-order kinetics due to reaction of H + with e aq- under argon or with OH - under N 2O. In the alkaline pH range OH - release is involved in the relaxation process resulting from the radical cation after excitation of the conjugate base. No indication of a specific spatial correlation of the charged species, as proposed earlier by Grossweiner for other systems, was found.

  18. Compound matrices

    NASA Astrophysics Data System (ADS)

    Kravvaritis, Christos; Mitrouli, Marilena

    2009-02-01

    This paper studies the possibility to calculate efficiently compounds of real matrices which have a special form or structure. The usefulness of such an effort lies in the fact that the computation of compound matrices, which is generally noneffective due to its high complexity, is encountered in several applications. A new approach for computing the Singular Value Decompositions (SVD's) of the compounds of a matrix is proposed by establishing the equality (up to a permutation) between the compounds of the SVD of a matrix and the SVD's of the compounds of the matrix. The superiority of the new idea over the standard method is demonstrated. Similar approaches with some limitations can be adopted for other matrix factorizations, too. Furthermore, formulas for the n - 1 compounds of Hadamard matrices are derived, which dodge the strenuous computations of the respective numerous large determinants. Finally, a combinatorial counting technique for finding the compounds of diagonal matrices is illustrated.

  19. Determination of 1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene and related compounds in marine pore water by automated thermal desorption-gas chromatography/mass spectrometry using disposable optical fiber.

    PubMed

    Eganhouse, Robert P; DiFilippo, Erica L

    2015-10-01

    A method is described for determination of ten DDT-related compounds in marine pore water based on equilibrium solid-phase microextraction (SPME) using commercial polydimethylsiloxane-coated optical fiber with analysis by automated thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Thermally cleaned fiber was directly exposed to sediments and allowed to reach equilibrium under static conditions at the in situ field temperature. Following removal, fibers were rinsed, dried and cut into appropriate lengths for storage in leak-tight containers at -20°C. Analysis by TD-GC/MS under full scan (FS) and selected ion monitoring (SIM) modes was then performed. Pore-water method detection limits in FS and SIM modes were estimated at 0.05-2.4ng/L and 0.7-16pg/L, respectively. Precision of the method, including contributions from fiber handling, was less than 10%. Analysis of independently prepared solutions containing eight DDT compounds yielded concentrations that were within 6.9±5.5% and 0.1±14% of the actual concentrations in FS and SIM modes, respectively. The use of optical fiber with automated analysis allows for studies at high temporal and/or spatial resolution as well as for monitoring programs over large spatial and/or long temporal scales with adequate sample replication. This greatly enhances the flexibility of the technique and improves the ability to meet quality control objectives at significantly lower cost. PMID:26346188

  20. Microoptical compound lens

    DOEpatents

    Sweatt, William C.; Gill, David D.

    2007-10-23

    An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

  1. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A.

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  2. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  3. Effect of ring coordination of pyridine-3,5-dicarboxylate and metatungstate to Ln ions on metatungstate structure: Synthesis, structure and optical property of four new compounds

    SciTech Connect

    Liu Dandan; Chen Yaguang; Zhang Chunjing; Meng Huaxin; Zhang Zhichao; Zhang Chunxia

    2011-06-15

    Four novel compounds based on {alpha}-metatungstate [H{sub 2}W{sub 12}O{sub 40}]{sup 6-} (W{sub 12}) and Ln-organic complexes, (NH{sub 4}){sub 4}[Ln{sub 2}(L){sub 2}(H{sub 2}O){sub 9}(H{sub 2}W{sub 12}O{sub 40})].nH{sub 2}O (Ln=Eu{sup III} (1), Gd{sup III} (2), Dy{sup III} (4), n=11; Tb{sup III} (3), n=12; L=pyridine-3,5-dicarboxylate dianion) have been synthesized in aqueous solution and characterized by element analysis, IR spectrometry and thermogravimetric analysis. Single-crystal X-ray diffraction analyses reveal these compounds are isostructural with a P21/n space group. The W{sub 12} cluster acting as a tridentate ligand connects three Ln{sup 3+} ions, in turn, each Ln2 ion links two W{sub 12} clusters, as a result, a W{sub 12}-Ln polymeric chain is formed. Coordination of pyridine-3,5-dicarboxylate ligands to the Ln{sup 3+} ions leads to a Ln-L polymeric chain. The two chains, W{sub 12}-Ln and Ln-L, share Ln2 ions, resulting in a 2-D layer. Ring coordination of pyridine-3,5-dicarboxylate and W{sub 12} to the Ln ions changes some bond angles of W{sub 12} that leads to a slight distortion of W{sub 12} and splitting of vibration band of W-Oc-W. Solid-state photoluminescence properties of compounds 1-4 have been investigated. - Graphical abstract: Four two-dimensional {alpha}-metatungstate and Ln-pyridine-3,5-dicarboxylate compounds have been synthesized. During the research, we elucidated the effect of ring coordination of pyridine-3,5-dicarboxylate on the structures of the POM-based hybrids. Highlights: > Four new 2-D compounds based on [H{sub 2}W{sub 12}O{sub 40}]{sup 6-} and Ln-organic complexes have been synthesized. > We study the ring coordination of pyridine-3, 5-dicarboxylate and W{sub 12} to Ln ions. > The luminescent properties of these compounds have been investigated.

  4. Surface defect free growth of a spin dimer TlCuCl3 compound crystals and investigations on its optical and magnetic properties

    NASA Astrophysics Data System (ADS)

    Ryu, Gihun; Son, Kwanghyo

    2016-05-01

    A defect-free high quality single crystal of spin dimer TlCuCl3 compound is firstly synthesized at the optimal growth temperature using the vertical Bridgman method. In this study, we clearly found that the cupric chloride is easily decomposed into the Cl- deficient composition at ≥470 °C. The Cl-- related gas phase at the high temperature region also always gives rise to a pinhole-like surface defect at the surface of crystal. Therefore, we clearly verified an exotic anisotropic magnetic behavior (anisotropic ratio of Mb/M(201) at 2 K, 7 T=10) using the defect-free TlCuCl3 crystals in this three-dimensional spin dimer TlCuCl3 compound, relatively stronger magnetic ordering in the H//b than that of H//(201) direction at above the transition magnetic field.

  5. Compound C2, a product of the reaction of oxygen and the mixed-valence state of cytochrome oxidase. Optical evidence for a type-I copper.

    PubMed

    Chance, B; Saronio, C; Leigh, J S

    1979-03-01

    Compound C2 is a product of the reaction of O2 and the mixed-valence state of cytochrome oxidase. The mixed-valence state of membrane-bound cytochrome oxidase is obtained at -24 degrees C, by using either ferricyanide or yeast peroxidase complex ES as oxidants, and the configurations of oxidized haem a and its associated copper (a3+Cua2+) and of reduced haem a3 and its associated copper (ac3+.CO.Cua3+) are obtained. The mixed-valence-state cytochrome oxidase mixed with O2 at -24 degrees C and flash-photolysed at -60 to -100 degrees C reacts with O2 and initially forms an oxy compound (A2) similar to that formed from the fully reduced state (A1). Thereafter the course of the reaction differs from that obtained in the fully reduced state, and absorbance increases are observed at 740--750 nm and 609 nm and a decrease at 444 nm, with no increase in absorbance at 655 nm. One possible attribution of the absorbance increases is to charge-transfer interaction between the iron of haem a3 and the copper associated with haem a3, Cua3(2+), having properties of a type-I 'blue' copper. A possible attribution of the decrease in absorbance at 444 nm is to liganding of a3(2+). A related explanation is that the 609 nm absorbance involves a charge-transfer interaction of both iron and copper as a mixed-valence binuclear complex, Cua3, having properties of a non-blue copper. Intermediates in addition to Compound C2 are not yet identifiable by chemical or spectroscopic tests. The kinetic and equilibrium properties of Compound C2 are described. PMID:220956

  6. Magnetic, Mössbauer and optical spectroscopic properties of the AFe3O(PO4)3 (A = Ca, Sr, Pb) series of powder compounds

    NASA Astrophysics Data System (ADS)

    El Hafid, Hassan; Velázquez, Matias; El Jazouli, Abdelaziz; Wattiaux, Alain; Carlier, Dany; Decourt, Rodolphe; Couzi, Michel; Goldner, Philippe; Delmas, Claude

    2014-10-01

    AFe3O(PO4)3 (A = Ca, Sr and Pb) powder compounds were studied by means of X-ray diffraction (XRD), electron-probe microanalysis (EPMA) coupled with wavelength dispersion spectroscopy (WDS), Raman and diffuse reflectance spectroscopies, specific heat and magnetic properties measurements. Magnetization, magnetic susceptibility and specific heat measurements carried out on AFe3O(PO4)3 (A = Sr, Ca and Pb) powders firmly establish a series of three ferromagnetic (FM)-like second order phase transitions spanned over the 32-8 K temperature range. Room temperature Mössbauer spectroscopy and associated DFT calculations confirm the existence of three crystallographically non equivalent Fe3+ sites in the three compounds. Mössbauer spectra recorded as a function of temperature in the PbFe3O(PO4)3 compound also establishes the occurrence of two purely magnetic and reversible phase transitions at 32 and 10 K. Diffuse reflectance measurements reveal two broad absorption bands at 1047 and 837 nm, in both PbFe3O(PO4)3 and SrFe3O(PO4)3 powders, with peak cross sections ˜10-20 cm2 typical of spin-forbidden and forced electric dipole intraconfigurational transitions.

  7. Characterization of hydrogenated amorphous germanium compounds obtained by x-ray chemical vapor deposition of germane: Effect of the irradiation dose on optical parameters and structural order

    SciTech Connect

    Arrais, Aldo; Benzi, Paola; Bottizzo, Elena; Demaria, Chiara

    2007-11-15

    Hydrogenated nonstoichiometric germanium materials have been produced by x-ray activated-chemical vapor deposition from germane. The reactions pattern leading to the solid products has been investigated. The dose effect on the composition, the local bonding configuration, and structural characteristics of the deposited solids has been studied using infrared absorption and Raman spectroscopy and has been discussed. Optical parameters have been also determined from ultraviolet-visible spectrophotometry data. The results show that the solids are formed by a random bound network of germanium and hydrogen atoms with a-Ge zones dispersed in the matrix. The Raman results and optical parameters indicate that the structural order, both short-range and intermediate-range, decreases with increasing irradiation time. This behavior suggests that the solid is involved in the reactions leading to the final product and indicates that the formation of amorphous germanium zones is stimulated by postdeposition irradiation, which induces compositional and structural modifications.

  8. Thin compound-eye camera.

    PubMed

    Duparré, Jacques; Dannberg, Peter; Schreiber, Peter; Bräuer, Andreas; Tünnermann, Andreas

    2005-05-20

    An artificial compound-eye objective fabricated by micro-optics technology is adapted and attached to a CMOS sensor array. The novel optical sensor system with an optics thickness of only 0.2 mm is examined with respect to resolution and sensitivity. An optical resolution of 60 x 60 pixels is determined from captured images. The scaling behavior of artificial compound-eye imaging systems is analyzed. Cross talk between channels fabricated by different technologies is evaluated, and the influence on an extension of the field of view by addition of a (Fresnel) diverging lens is discussed. The lithographic generation of opaque walls between channels for optical isolation is experimentally demonstrated. PMID:15929282

  9. Microoptical telescope compound eye

    NASA Astrophysics Data System (ADS)

    Duparré, Jacques W.; Schreiber, Peter; Matthes, André; Pshenay–Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70ºx10º field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results.

  10. Microoptical telescope compound eye.

    PubMed

    Duparré, Jacques; Schreiber, Peter; Matthes, André; Pshenay-Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor-Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70 masculinex10 masculine field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non-sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results. PMID:19494951

  11. Exploring the Magnetic Susceptibility of a Haldane Compound Sm2 BaNiO5 : Optical Spectroscopy of Sm^{3+} Kramers Doublets

    NASA Astrophysics Data System (ADS)

    Galkin, A. S.; Klimin, S. A.

    2016-07-01

    An optical spectroscopic study of quasi-Haldane chain nickelate Sm2 BaNiO5 is presented. A temperature-dependent splitting of the ground-state Kramers doublet of the Sm^{3+} ion due to an antiferromagnetic ordering at TN = 55 K has been obtained experimentally and used to calculate the Schottky-type anomaly in magnetic susceptibility. The value of the magnetic moment of Sm^{3+} ion at zero temperature has been estimated within the model of the ground doublet. One-dimensional magnetic behavior of the nickel subsystem is emphasized.

  12. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  13. Growth, characterization, optical and vibrational properties of Sm3+ doped Cd0.8Zn0.2S semiconductor compounds

    NASA Astrophysics Data System (ADS)

    Yellaiah, G.; Hadasa, K.; Nagabhushanam, M.

    2014-01-01

    Undoped and doped polycrystalline Cd0.8Zn0.2S powders with different amounts of samarium (0.01, 0.02, 0.03, 0.04 and 0.05 M) were synthesized by the controlled co-precipitation technique. Effect of the Sm3+ on structural, elemental, optical and vibrational properties of Cd0.8Zn0.2S: Smx samples were investigated. X-ray diffraction (XRD) results showed that the samples prepared were polycrystalline with hexagonal structure. From the XRD patterns, the average crystallite size was calculated it was about 45-90 nm. The band gap of these samples is estimated from the optical absorption studies. The samples showed direct band gap, which varies from 2.52 to 3.18 eV. Fourier transform infrared spectroscopy (FTIR) showed the characteristic vibrational modes of Cd-S and Zn-S in the wave number range 621-821 cm-1. Experimental and XRD densities were calculated and analyzed.

  14. Optical doping of Al{sub x}Ga{sub 1-x}N compounds by ion implantation of Tm ions

    SciTech Connect

    Fialho, M.; Lorenz, K.; Magalhaes, S.; Redondo-Cubero, A.; Rodrigues, J.; Santos, N. F.; Monteiro, T.; Alves, E.

    2012-11-06

    Al{sub x}Ga{sub 1-x}N (0optical efficiency. The ions were implanted under random and channeled orientations with a fluence of 1 Multiplication-Sign 10{sup 15}cm{sup -2}. The damage profile and the defects' nature were investigated by Rutherford Backscattering/Channeling Spectrometry and High Resolution X-ray Diffraction. The structural measurements show a higher resistance of the lattice to irradiation damage with the increase of the AlN content. Results of the angular scans measured along the <0001> axis for samples with AlN contents of 0.15 and 0.77 suggest a relation between the AlN content and Tm specific sites in the lattice. Rapid thermal annealing treatments under N{sub 2} ambient were performed to remove damage and promote optical activation of rare earth intra-4f{sup n} transitions. After annealing the observed intraionic emissions of Tm{sup 3+} ions were characterized by photoluminescence.

  15. Magnetic and optical properties in the 1D TM-O chain compounds Sr2TMO3 (TM = Ni, Co): A first-principle investigation

    NASA Astrophysics Data System (ADS)

    Gui, Hong; Li, Xin; Zhao, Zhenjie; Xie, Wenhui

    2016-03-01

    In this paper, we have calculated the structural, electronic, magnetic and optical properties of Sr2NiO3 and Sr2CoO3 using density functional theory (DFT) within generalized gradient approximation (GGA). The crystal structure of both materials is well described with Immm (No. 71) symmetry which are isostructural with Sr2CuO3 and both are quasi-one-dimensional (1D) rectangular lattice G-type antiferromagnets, in consistent with the experimental data. Due to a distortion, Sr2CoO3 lifts the near-degeneracy dxz and dyz states of the local Co electronic configuration, which demonstrates a strong coupling between the structural lattice and the electronic configuration. The calculated band structure shows a band gap of 1.376 eV for Sr2NiO3 and a band gap of 1.735 eV for Sr2CoO3. Ni and Co ions are in the high-spin S = 1 and S = 3/2 configurations with the magnetic moments of 1.585 μB and 2.587 μB, respectively. Based on the Heisenberg Hamiltonian model, we conclude that the superexchange intrachain TM-O-TM superexchange interaction is predominant and interaction between the 1D chains is weak. According to the calculated dielectric function, absorption spectrum and electron energy loss spectrum, the optical responses suggest that Sr2NiO3 shows the unique anisotropic structure and interaction of the application in optoelectronics.

  16. Black and Brown Carbon in Biogenic Settings with Different Levels of Anthropogenic Influence, and The Effect of Semivolatile Compounds on Aerosol Optical Properties

    NASA Astrophysics Data System (ADS)

    Tasoglou, A.; Ramachandran, S.; Khlystov, A.; Saha, P.; Grieshop, A. P.; Pandis, S. N.

    2015-12-01

    Secondary organic aerosol (SOA) is a major contributor to the global aerosol burden. Black carbon (BC) is a significant climate warming agent, while light-absorbing organic carbon (brown carbon, BrC), also impacts the atmospheric radiative balance. The optical properties of ambient aerosols can be affected by biogenic SOA through the lensing effect (coating of BC cores by semivolatile SOA), and by the potential formation of BrC from biogenic sources influenced by anthropogenic sources. To evaluate these effects, measurements of ambient aerosol optical properties and BC concentrations were made in rural Centreville, AL (a remote site with little anthropogenic influence) in summer 2013 and at Duke Forest in Chapel Hill, NC (a site close to high density vehicular traffic and industrial sources), during summer 2015. Photoacoustic extinctiometers (PAX, 405 nm and 532 nm) measured particulate light absorption and a single particle soot photometer (SP2) measured BC mass at both locations. A seven-wavelength Aethalometer and a three-wavelength nephelometer were also deployed at Duke Forest. A third PAX (870 nm) was deployed at Centreville. For absorption and BC measurements, the sample was cycled between a dry line and a dry/thermally-denuded line. Hourly samples were collected with a steam jet aerosol collector (SJAC) for online (2013) and offline (2015) chemical composition analysis. BC concentrations were generally higher at Duke Forest compared to the rural Centreville site. The Aethalometer readings at Duke Forest show greater absorption at the shorter wavelengths (370 nm and 470 nm) than expected from the absorption at 880 nm coupled with an inverse wavelength dependence, suggesting the presence of brown carbon. This presentation will examine the evidence for brown carbon at the two sites, as well as the effect of non-BC coatings on BC light absorption (the lensing effect.)

  17. Layer specific optical band gap measurement at nanoscale in MoS2 and ReS2 van der Waals compounds by high resolution electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Dileep, K.; Sahu, R.; Sarkar, Sumanta; Peter, Sebastian C.; Datta, R.

    2016-03-01

    Layer specific direct measurement of optical band gaps of two important van der Waals compounds, MoS2 and ReS2, is performed at nanoscale by high resolution electron energy loss spectroscopy. For monolayer MoS2, the twin excitons (1.8 and 1.95 eV) originating at the K point of the Brillouin zone are observed. An indirect band gap of 1.27 eV is obtained from the multilayer regions. Indirect to direct band gap crossover is observed which is consistent with the previously reported strong photoluminescence from the monolayer MoS2. For ReS2, the band gap is direct, and a value of 1.52 and 1.42 eV is obtained for the monolayer and multilayer, respectively. The energy loss function is dominated by features due to high density of states at both the valence and conduction band edges, and the difference in analyzing band gap with respect to ZnO is highlighted. Crystalline 1T ReS2 forms two dimensional chains like superstructure due to the clustering between four Re atoms. The results demonstrate the power of HREELS technique as a nanoscale optical absorption spectroscopy tool.

  18. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  19. Electronic Energy-Level Structures, Optical Line Strengths, and Correlation Crystal-Field Interactions in NEODYMIUM(3+) and ERBIUM(3+) Crystalline Compounds.

    NASA Astrophysics Data System (ADS)

    Quagliano, John Romolo

    Energy-level state structures of Nd^ {3+} (4f^3) and Er^{3+} (4f^ {11}) electronic configurations were analyzed in a total of 13 distinct chemical systems. The 13 systems included seven crystalline hosts that contain Nd ^{3+} ions (four garnets, one nonahydrate, one hexachloride, and one hexabromide), and six that contain Er^{3+} ions (three garnets, one oxalate-bioxalate, one hexachloride, and one hexabromide). Single crystal absorption spectra (polarized and unpolarized) and optical intensity data have been acquired for neat (rm Nd(H_2O)_9) (CF _3rm SO_3)_3 at cryogenic temperatures over the UV to near-IR energy range. Single crystal polarized orthoaxial absorption, excitation, and emission experiments were performed on Er^{3+}-doped CsCdBr _3. Model Hamiltonians were developed and used to calculate lanthanide 4f^{rm N } electronic structures. These Hamiltonians were constructed and parametrized to represent both atomic and crystal-field interactions in various host materials. A Hamiltonian with atomic and first-order crystal-field operators gave a very good initial description of the energy-level structures, and a second-order correlation crystal-field (CCF) refinement produced excellent results for some multiplet manifolds that are not well characterized by the first -order (one-particle) crystal-field interactions alone. The ^2rm H(2)_{11/2} , ^2{F}(2)_ {5/2}, and ^2rm F(2) _{7/2} multiplet manifolds of Nd ^{3+} and the ^2rm H(2)_{9/2}, ^2H(2) _{11/2}, and ^4 rm G_{11/2} multiplet manifolds of Er^{3+} were markedly improved after a maximum of three CCF operators were added to the Hamiltonian. The studies showed that since the Nd^{3+} and Er ^{3+} ions share the same SLJ (Russell -Saunders) basis of atomic states, then their respective energy-level structures are sensitive to the same CCF operators. The magnitudes of the CCF interactions were found to be typically 10% of the first-order one-particle crystal-field interactions. The present work establishes a new

  20. Highly porous CdO nanowires: preparation based on hydroxy- and carbonate-containing cadmium compound precursor nanowires, gas sensing and optical properties.

    PubMed

    Guo, Zheng; Li, Minqiang; Liu, Jinhuai

    2008-06-18

    Highly porous cadmium oxide (CdO) nanowires have been prepared by calcining the hydroxy- and carbonate-containing cadmium compound precursor nanowires. The large-scale precursor nanowires were synthesized through a hydrothermal method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize and analyze the as-synthesized precursor nanowires as well as the calcined products. It was revealed that the wire-like morphology of the precursor was fundamentally retained during the process of calcination and the CdO nanowires obtained were polycrystalline with highly porous structures. In order to illustrate the formation mechanism of the porous structures, the morphology and composition evolutions of the precursor nanowires under different stages of the calcining process were further investigated via SEM, x-ray diffraction (XRD) and infrared (IR) absorbance spectroscopy. Gas sensing has been explored for the sensor device fabricated with highly porous CdO nanowires, which demonstrates that it has good response owing to its special structures and great selectivity to NO(x). Furthermore, the UV-visible and photoluminescence spectra of highly porous CdO nanowires have also been investigated. PMID:21825823

  1. Highly porous CdO nanowires: preparation based on hydroxy- and carbonate-containing cadmium compound precursor nanowires, gas sensing and optical properties

    NASA Astrophysics Data System (ADS)

    Guo, Zheng; Li, Minqiang; Liu, Jinhuai

    2008-06-01

    Highly porous cadmium oxide (CdO) nanowires have been prepared by calcining the hydroxy- and carbonate-containing cadmium compound precursor nanowires. The large-scale precursor nanowires were synthesized through a hydrothermal method. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to characterize and analyze the as-synthesized precursor nanowires as well as the calcined products. It was revealed that the wire-like morphology of the precursor was fundamentally retained during the process of calcination and the CdO nanowires obtained were polycrystalline with highly porous structures. In order to illustrate the formation mechanism of the porous structures, the morphology and composition evolutions of the precursor nanowires under different stages of the calcining process were further investigated via SEM, x-ray diffraction (XRD) and infrared (IR) absorbance spectroscopy. Gas sensing has been explored for the sensor device fabricated with highly porous CdO nanowires, which demonstrates that it has good response owing to its special structures and great selectivity to NOx. Furthermore, the UV-visible and photoluminescence spectra of highly porous CdO nanowires have also been investigated.

  2. Enhanced optical power of GaN-based light-emitting diode with compound photonic crystals by multiple-exposure nanosphere-lens lithography

    SciTech Connect

    Zhang, Yonghui; Wei, Tongbo Xiong, Zhuo; Shang, Liang; Tian, Yingdong; Zhao, Yun; Zhou, Pengyu; Wang, Junxi; Li, Jinmin

    2014-07-07

    The light-emitting diodes (LEDs) with single, twin, triple, and quadruple photonic crystals (PCs) on p-GaN are fabricated by multiple-exposure nanosphere-lens lithography (MENLL) process utilizing the focusing behavior of polystyrene spheres. Such a technique is easy and economical for use in fabricating compound nano-patterns. The optimized tilted angle is decided to be 26.6° through mathematic calculation to try to avoid the overlay of patterns. The results of scanning electron microscopy and simulations reveal that the pattern produced by MENLL is a combination of multiple ovals. Compared to planar-LED, the light output power of LEDs with single, twin, triple, and quadruple PCs is increased by 14.78%, 36.03%, 53.68%, and 44.85% under a drive current 350 mA, respectively. Furthermore, all PC-structures result in no degradation of the electrical properties. The stimulated results indicate that the highest light extraction efficiency of LED with the clover-shape triple PC is due to the largest scattering effect on propagation of light from GaN into air.

  3. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  4. Organic nonlinear optical materials

    NASA Technical Reports Server (NTRS)

    Umegaki, S.

    1987-01-01

    Recently, it became clear that organic compounds with delocalized pi electrons show a great nonlinear optical response. Especially, secondary nonlinear optical constants of more than 2 digits were often seen in the molecular level compared to the existing inorganic crystals such as LiNbO3. The crystallization was continuously tried. Organic nonlinear optical crystals have a new future as materials for use in the applied physics such as photomodulation, optical frequency transformation, opto-bistabilization, and phase conjugation optics. Organic nonlinear optical materials, e.g., urea, O2NC6H4NH2, I, II, are reviewed with 50 references.

  5. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  6. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  7. Substituent effects on the optical properties of naphthalenediimides: A frontier orbital analysis across the periodic table.

    PubMed

    Mulder, Joshua R; Guerra, Célia Fonseca; Slootweg, J Chris; Lammertsma, Koop; Bickelhaupt, F Matthias

    2016-01-15

    A comprehensive theoretical treatment is presented for the electronic excitation spectra of ca. 50 different mono-, di-, and tetrasubstituted naphthalenediimides (NDI) using time-dependent density functional theory (TDDFT) at ZORA-CAM-B3LYP/TZ2P//ZORA-BP86/TZ2P with COSMO for simulating the effect of dichloromethane (DCM) solution. The substituents -XHn are from groups 14-17 and rows 2-5 of the periodic table. The lowest dipole-allowed singlet excitation (S0 -S1 ) of the monosubstituted NDIs can be tuned from 3.39 eV for -F to 2.42 eV for -TeH, while the S0 -S2 transition is less sensitive to substitution with energies ranging between 3.67 eV for -CH3 and 3.44 eV for -SbH2 . In the case of NDIs with group-15 and -16 substituents, the optical transitions strongly depend on the extent to which -XHn is planar or pyramidal as well as on the possible formation of intramolecular hydrogen bonds. The accumulative effect of double and quadruple substitution leads in general to increasing bathochromic shifts, but the increased steric hindrance in tetrasubstituted NDIs can lead to deformations that diminish the effectiveness of the substituents. Detailed analyses of the Kohn-Sham orbital electronic structure in monosubstituted NDIs reveal the mesomeric destabilization of the HOMO as the primary cause of the bathochromic shift of the S0-S1 transition. PMID:26444551

  8. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  9. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  10. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  12. Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- μV-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  13. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  14. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA`s fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  15. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  16. Bismaleimide compounds

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

    Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  17. Bismaleimide compounds

    DOEpatents

    Adams, J.E.; Jamieson, D.R.

    1986-01-14

    Bismaleimides of the formula shown in the diagram wherein R[sub 1] and R[sub 2] each independently is H, C[sub 1-4]-alkyl, C[sub 1-4]-alkoxy, Cl or Br, or R[sub 1] and R[sub 2] together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R[sub 1] and R[sub 2] are not t-butyl or t-butoxy; X is O, S or Se; n is 1--3; and the alkylene bridging group, optionally, is substituted by 1--3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  18. COMPOUND SPECIFIC IMPRINTED NANOSPHERES FOR OPTICAL SENSING

    EPA Science Inventory

    The U.S. Geological Survey reported in the March 2002 issue of Environmental Science and Technology that steroids, hormones, antibiotics, and numerous other prescription and nonprescription drugs, e.g., caffeine and ibuprofen, are present in streams throughou...

  19. A novel class of compounds--superalkalides: M⁺(en)₃M'₃O⁻ (M, M' = Li, Na, and K; en = ethylenediamine)-with excellent nonlinear optical properties and high stabilities.

    PubMed

    Mai, Jinmei; Gong, Shida; Li, Nan; Luo, Qiong; Li, Zhiru

    2015-11-21

    With the aid of ab initio calculations at the MP2 level of theory, we designed a novel class of inorganic salts, M(+)(en)3M3'O(-) (M, M' = Li, Na, and K), by using the M3'O superalkalis. These compounds are the first examples of inorganic salts wherein the superalkali occupies the anionic site, and termed superalkalides. The electronic structural features of the M(+)(en)3M3'O(-) superalkalides are very similar to those of the corresponding M(+)(en)3M'(-) alkalides which have been reported by Zurek (J. Am. Chem. Soc., 2011, 133, 4829). In this study, the calculated NLO properties of M(+)(en)3M3'O(-) and M(+)(en)3M'(-) (M, M' = Li, Na, and K) show that both superalkalides and alkalides have significantly large first hyperpolarizabilities (β0) with the values in the range of 7.80 × 10(3) to 9.16 × 10(4) a.u. and 7.95 × 10(3) to 1.84 × 10(5) a.u., respectively. Computations on the stabilities of M(+)(en)3M3'O(-) and M(+)(en)3M'(-) demonstrate that the M(+)(en)3M3'O(-) superalkalides are preferably stable than the corresponding M(+)(en)3M'(-) alkalides because of the presence of hydrogen bonds in M(+)(en)3M3'O(-). Therefore, the designed superalkalides, M(+)(en)3M3'O(-) (M, M' = Li, Na, and K), with excellent nonlinear optical properties and high stabilities are greatly promising candidates for NLO materials. We hope that this article could attract more research interest in superatom chemistry and for further experimental research. PMID:26446270

  20. Optic glioma

    MedlinePlus

    Glioma - optic; Optic nerve glioma; Juvenile pilocytic astrocytoma; Brain cancer - optic glioma ... Optic gliomas are rare. The cause of optic gliomas is unknown. Most optic gliomas are slow-growing ...

  1. Miniature curved artificial compound eyes

    PubMed Central

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L’Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A.; Franceschini, Nicolas

    2013-01-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  2. Miniature curved artificial compound eyes.

    PubMed

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-01

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories. PMID:23690574

  3. Optic neuritis

    MedlinePlus

    Retro-bulbar neuritis; Multiple sclerosis - optic neuritis; Optic nerve - optic neuritis ... The exact cause of optic neuritis is unknown. The optic nerve carries visual information from your eye to the brain. The nerve can swell when ...

  4. An investigation of new infrared nonlinear optical material: BaCdSnSe4, and three new related centrosymmetric compounds: Ba2SnSe4, Mg2GeSe4, and Ba2Ge2S6.

    PubMed

    Wu, Kui; Su, Xin; Yang, Zhihua; Pan, Shilie

    2015-12-14

    A series of new metal chalcongenides, BaCdSnSe4 (1), Ba2SnSe4 (2), Mg2GeSe4 (3), and Ba2Ge2S6 (4), were successfully synthesized for the first time. Among them, compounds 2 and 4 were prepared by a molten flux method with Zn as the flux. In their structures, all of them have MQ4 (M = Sn, Ge; Q = S, Se) units. For compound 1, the CdSe4 and SnSe4 groups are connected to form CdSnSe6 layers and these layers are linked together by the Ba atoms. Compounds 2 and 3 are composed of isolated MSe4 (M = Sn, Ge) units and charge-balanced by the Ba or Mg atoms, respectively, while compound 4 has infinite ∞(GeS3)n chains, which is different from the structures of the other three compounds that only have isolated MSe4 (M = Sn, Ge) units. The measured IR and Raman data of the title compounds show wide infrared transmission ranges. The experimental band gaps of compounds 1, 2, 3 and were determined to be 1.79, 1.90, and 2.02 eV, respectively. Band structures were also calculated and indicate that their tetrahedral units, such as [SnSe4], [GeS4] and [GeSe4], determine the energy band gaps of the title compounds, respectively. As for compound 1, based on fundamental light at 2.09 μm, the experimental second harmonic generation (SHG) response is about 1.6 times that of the benchmark AgGaS2, which is also consistent with the calculated value. Based on the above results, compound 1 has promising applications in the IR field as a NLO material. PMID:26509847

  5. Compounding in Ukraine.

    PubMed

    Zdoryk, Oleksandr A; Georgiyants, Victoriya A; Gryzodub, Oleksandr I; Schnatz, Rick

    2013-01-01

    Pharmaceutical compounding in modern Ukraine has a rich history and goes back to ancient times. Today in the Ukraine, there is a revival of compounding practice, the opening of private compounding pharmacies, updating of legislative framework and requirements of the State Pharmacopeia of Ukraine for compounding preparations, and the introduction of Good Pharmaceutical Practice. PMID:23696172

  6. Films Containing Optically Nonlinear Diacetylene Monomer

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.; Mcmanus, Samuel P.; Frazier, Donald O.

    1993-01-01

    Solid films exhibiting nonlinear optical properties prepared as mixtures of poly(methyl methacrylate) with various amounts of diacetylene monomer called "compound 1" in article, "Synthesizing Diacetylenes With Nonlinear Optical Properties" (MFS-26186). Useful as phase-conjugate mirrors in laser-beam communications and as optical switches in optical computers. This particular diacetylene monomer exhibits strong third-order nonlinear optical properties, both in pure form and in solution.

  7. Bio-inspired hemispherical compound eye camera

    NASA Astrophysics Data System (ADS)

    Xiao, Jianliang; Song, Young Min; Xie, Yizhu; Malyarchuk, Viktor; Jung, Inhwa; Choi, Ki-Joong; Liu, Zhuangjian; Park, Hyunsung; Lu, Chaofeng; Kim, Rak-Hwan; Li, Rui; Crozier, Kenneth B.; Huang, Yonggang; Rogers, John A.

    2014-03-01

    Compound eyes in arthropods demonstrate distinct imaging characteristics from human eyes, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. Artificial imaging systems with similar geometries and properties are of great interest for many applications. However, the challenges in building such systems with hemispherical, compound apposition layouts cannot be met through established planar sensor technologies and conventional optics. We present our recent progress in combining optics, materials, mechanics and integration schemes to build fully functional artificial compound eye cameras. Nearly full hemispherical shapes (about 160 degrees) with densely packed artificial ommatidia were realized. The number of ommatidia (180) is comparable to those of the eyes of fire ants and bark beetles. The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors, which were fabricated in the planar geometries and then integrated and elastically transformed to hemispherical shapes. Imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

  8. Quantitative structure carcinogenicity relationship for detecting structural alerts in nitroso-compounds

    SciTech Connect

    Helguera, Aliuska Morales Cordeiro, M. Natalia D.S.; Perez, Miguel Angel Cabrera; Combes, Robert D.; Gonzalez, Maykel Perez

    2008-09-01

    In this work, Quantitative Structure-Activity Relationship (QSAR) modelling was used as a tool for predicting the carcinogenic potency of a set of 39 nitroso-compounds, which have been bioassayed in male rats by using the oral route of administration. The optimum QSAR model provided evidence of good fit and performance of predicitivity from training set. It was able to account for about 84% of the variance in the experimental activity and exhibited high values of the determination coefficients of cross validations, leave one out and bootstrapping (q{sup 2}{sub LOO} = 78.53 and q{sup 2}{sub Boot} = 74.97). Such a model was based on spectral moments weighted with Gasteiger-Marsilli atomic charges, polarizability and hydrophobicity, as well as with Abraham indexes, specifically the summation solute hydrogen bond basicity and the combined dipolarity/polarizability. This is the first study to have explored the possibility of combining Abraham solute descriptors with spectral moments. A reasonable interpretation of these molecular descriptors from a toxicological point of view was achieved by means of taking into account bond contributions. The set of relationships so derived revealed the importance of the length of the alkyl chains for determining carcinogenic potential of the chemicals analysed, and were able to explain the difference between mono-substituted and di-substituted nitrosoureas as well as to discriminate between isomeric structures with hydroxyl-alkyl and alkyl substituents in different positions. Moreover, they allowed the recognition of structural alerts in classical structures of two potent nitrosamines, consistent with their biotransformation. These results indicate that this new approach has the potential for improving carcinogenicity predictions based on the identification of structural alerts.

  9. COMPACT, CONTINUOUS MONITORING FOR VOLATILE ORGANIC COMPOUNDS - PHASE I

    EPA Science Inventory

    Improved methods for onsite measurement of multiple volatile organic compounds are needed for process control, monitoring, and remediation. This Phase I SBIR project sets forth an optical measurement method that meets these needs. The proposed approach provides an instantaneous m...

  10. Device for aqueous detection of nitro-aromatic compounds

    DOEpatents

    Reagen, W.K.; Schulz, A.L.; Ingram, J.C.; Lancaster, G.D.; Grey, A.E.

    1994-04-26

    This invention relates to a compact and portable detection apparatus for nitro-aromatic based chemical compounds, such as nitrotoluenes, dinitrotoluenes, and trinitrotoluene (TNT). The apparatus is based upon the use of fiber optics using filtered light. The preferred process of the invention relies upon a reflective chemical sensor and optical and electronic components to monitor a decrease in fluorescence when the nitro-aromatic molecules in aqueous solution combine and react with a fluorescent polycyclic aromatic compound. 4 figures.

  11. Device for aqueous detection of nitro-aromatic compounds

    DOEpatents

    Reagen, William K.; Schulz, Amber L.; Ingram, Jani C.; Lancaster, Gregory D.; Grey, Alan E.

    1994-01-01

    This invention relates to a compact and portable detection apparatus for ro-aromatic based chemical compounds, such as nitrotoluenes, dinitrotoluenes, and trinitrotoluene (TNT). The apparatus is based upon the use of fiber optics using filtered light. The preferred process of the invention relies upon a reflective chemical sensor and optical and electronic components to monitor a decrease in fluorescence when the nitro-aromatic molecules in aqueous solution combine and react with a fluorescent polycyclic aromatic compound.

  12. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  13. Dinitroso and polynitroso compounds

    PubMed Central

    Gowenlock, Brian G.; Richter-Addo, George B.

    2005-01-01

    The growing interest in the chemistry of C-nitroso compounds (RN=O; R = alkyl or aryl group) is due in part to the recognition of their participation in various metabolic processes of nitrogen-containing compounds. C-Nitroso compounds have a rich organic chemistry in their own right, displaying interesting intra- and intermolecular dimerization processes and addition reactions with unsaturated compounds. In addition, they have a fascinating coordination chemistry. While most of the attention has been directed towards C-nitroso compounds containing a single –NO moiety, there is an emerging area of research dealing with dinitroso and polynitroso compounds. In this critical review, we present and discuss the synthetic routes and properties of these relatively unexplored dinitroso and polynitroso compounds, and suggest areas of further development involving these compounds. (126 references.) PMID:16100619

  14. Caulking compound poisoning

    MedlinePlus

    Caulking compounds are substances used to seal cracks and holes around windows and other openings. Caulking compound poisoning occurs when someone swallows these substances. This is for information only and not for use in the ...

  15. Organometallic Salts Generate Optical Second Harmonics

    NASA Technical Reports Server (NTRS)

    Marder, Seth R.; Perry, Joseph W.

    1991-01-01

    Series of organometallic salts exhibit large second-order dielectric susceptibilities, as evidenced by generation of second harmonics when illuminated at visible and near-infrared wavelengths. Investigations of these and related compounds continue with view toward development of materials for use as optical second-harmonic generators, electro-optical modulators, optical switches, piezoelectric sensors, and parametric crystals.

  16. Excitonic effects in oxyhalide scintillating host compounds

    SciTech Connect

    Shwetha, G.; Kanchana, V.; Valsakumar, M. C.

    2014-10-07

    Ab-initio calculations based on density functional theory have been performed to study the electronic, optical, mechanical, and vibrational properties of scintillator host compounds YOX (X = F, Cl, Br, and I). Semiempirical dispersion correction schemes are used to find the effect of van der Waals forces on these layered compounds and we found this effect to be negligible except for YOBr. Calculations of phonons and elastic constants showed that all the compounds studied here are both dynamically and mechanically stable. YOF and YOI are found to be indirect band gap insulators while YOCl and YOBr are direct band gap insulators. The band gap is found to decrease as we move from fluorine to iodine, while the calculated refractive index shows the opposite trend. As the band gap decreases on going down the periodic table from YOF to YOI, the luminescence increases. The excitonic binding energy calculated, within the effective mass approximation, is found to be more for YOF than the remaining compounds, suggesting that the excitonic effect to be more in YOF than the other compounds. The optical properties are calculated within the Time-Dependent Density Functional Theory (TDDFT) and compared with results obtained within the random phase approximation. The TDDFT calculations, using the newly developed bootstrap exchange-correlation kernel, showed significant excitonic effects in all the compounds studied here.

  17. Compound prism design principles, I

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms. PMID:22423145

  18. Structural investigation of the Cu{sub 2}Se-In{sub 2}Se{sub 3}-Ga{sub 2}Se{sub 3} phase diagram, X-ray photoemission and optical properties of the Cu{sub 1-z}(In{sub 0.5}Ga{sub 0.5}){sub 1+z/3}Se{sub 2} compounds

    SciTech Connect

    Souilah, M.; Lafond, A.; Guillot-Deudon, C.; Harel, S.; Evain, M.

    2010-10-15

    Structures of compounds in the Cu{sub 2}Se-In{sub 2}Se{sub 3}-Ga{sub 2}Se{sub 3} system have been investigated through X-ray diffraction. Single crystal structure studies for the so-called stoichiometric compounds Cu(In,Ga)Se{sub 2} (CIGSe) confirm that the chalcopyrite structure (space group I4-bar 2d) is very flexible and can adapt itself to the substitution of Ga for In. On the other hand a structure modification is evidenced in the Cu{sub 1-z}(In{sub 0.5}Ga{sub 0.5}){sub 1+z/3}Se{sub 2} series when the copper vacancy ratio (z) increases; the chalcopyrite structure turns to a modified-stannite structure (I4-bar 2m) when z{>=}0.26. There is a continuous evolution of the structure from Cu{sub 0.74}(In{sub 0.5}Ga{sub 0.5}){sub 1.09}Se{sub 2} to Cu{sub 0.25}(In{sub 0.5}Ga{sub 0.5}){sub 1.25}Se{sub 2} ((i.e. Cu(In{sub 0.5}Ga{sub 0.5}){sub 5}Se{sub 8}), including Cu{sub 0.4}(In{sub 0.5}Ga{sub 0.5}){sub 1.2}Se{sub 2} (i.e. Cu(In{sub 0.5}Ga{sub 0.5}){sub 3}Se{sub 5}). From this single crystal structural investigation, it is definitively clear that no ordered vacancy compound exists in that series. X-ray photoemission spectroscopy study shows for the first time that the surface of powdered Cu{sub 1-z}(In{sub 0.5}Ga{sub 0.5}){sub 1+z/3}Se{sub 2} compounds (z{ne}0) is more copper-poor than the bulk. The same result has often been observed on CIGSe thin films material for photovoltaic applications. In addition, optical band gaps of these non-stoichiometric compounds increase from 1.2 to 1.4 eV when z varies from 0 to 0.75. - Abstract: Pseudo-ternary diagram in the Cu{sub 2}Se-In{sub 2}Se{sub 3}-Ga{sub 2}Se{sub 3} system showing the composition of all the synthesized compounds. The crystal structure of the compounds corresponding to red circles are presented in this study.

  19. Investigation of the Effect of Some Optically Active Imine Compounds on the Enzyme Activities of hCA-I and hCA-II under In Vitro Conditions: An Experimental and Theoretical Study.

    PubMed

    Tektas, Osman; Akkemik, Ebru; Baykara, Haci

    2016-06-01

    Inhibitors of carbonic anhydrase (hCA; EC 4.2.1.1) are used as medicines for many diseases. Therefore, they are very important. In this study, a known series of Schiff bases were synthesized and their effects on the activities of hCA-I and hCA-II, which are cytosolic isoenzymes of carbonic anhydrase, were investigated under in vitro conditions. The synthesized compounds (H1, H2, H3, and H4) were found to cause inhibition on enzyme activities of hCA-1 and hCA-II. IC50 values of H1, H2, H3, and H4 compounds were 140, 88, 201, and 271 μM for hCA-I enzyme activity and 134, 251, 79, and 604 μM for hCA-II enzyme activity, respectively. The synthesized Schiff bases were characterized by several methods, including (1) H NMR, FT-IR, elemental analysis, and polarimetric measurements. Correlation coefficient square values (R(2) ) of comparison of the theoretical and experimental (1) H NMR shifts for H1, H2, H3, and H4 compounds were found as 0.9781, 0.9814, 0.9758, and 0.8635, respectively. PMID:26762592

  20. Optic neuritis

    MedlinePlus

    ... pneumonia and other common upper respiratory tract infections Multiple sclerosis ... have optic neuritis without a disease such as multiple sclerosis have a good chance of recovery. Optic neuritis ...

  1. Production of epoxy compounds from olefinic compounds

    SciTech Connect

    Gelbein, A.P.; Kwon, J.T.

    1985-01-29

    Chlorine and tertiary alkanol dissolved in an inert organic solvent are reacted with aqueous alkali to produce tertiary alkyl hypochlorite which is recovered in the organic solvent and reacted with water and olefinically unsaturated compound to produce chlorohydrin and tertiary alkanol. Chlorohydrin and tertiary alkanol recovered in the organic solvent are contacted with aqueous alkali to produce the epoxy compound, and tertiary alkanol recovered in the organic solvent is recycled to hypochlorite production. The process may be integrated with the electrolytic production of chlorine, with an appropriate treatment of the recycle aqueous stream when required.

  2. Ecotoxicology of organofluorous compounds.

    PubMed

    Murphy, Margaret B; Loi, Eva I H; Kwok, Karen Y; Lam, Paul K S

    2012-01-01

    Organofluorous compounds have been developed for myriad purposes in a variety of fields, including manufacturing, industry, agriculture, and medicine. The widespread use and application of these compounds has led to increasing concern about their potential ecological toxicity, particularly because of the stability of the C-F bond, which can result in chemical persistence in the environment. This chapter reviews the chemical properties and ecotoxicology of four groups of organofluorous compounds: fluorinated refrigerants and propellants, per- and polyfluorinated compounds (PFCs), fluorinated pesticides, and fluoroquinolone antibiotics. These groups vary in their environmental fate and partitioning, but each raises concern in terms of ecological risk on both the regional and global scale, particularly those compounds with long environmental half-lives. Further research on the occurrence and toxicities of many of these compounds is needed for a more comprehensive understanding of their ecological effects. PMID:21952849

  3. XAFS Model Compound Library

    DOE Data Explorer

    Newville, Matthew

    The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

  4. Preparation of uranium compounds

    DOEpatents

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  5. Nitrodifluoraminoterphenyl compounds and processes

    DOEpatents

    Lerom, M.W.; Peters, H.M.

    1975-07-08

    This patent relates to the nitrodifluoraminoterphenyl compounds: 3,3''-bis (difluoramino)-2,2'' 4,4', 4'',6,6',6''-octanitro-m-terphenyl (DDONT) and 3,3''-bis(difluoramino)-2,2',2''4,4',4'',6,6',6''-nonanitro-m-terphenyl (DDNONA). Procedures are described wherein diamino precursors of the indicated compounds are prepared and the final compounds are obtained by a fluorination operation. The compounds are highly energetic and suitable for use as explosives and particularly in exploding bridge wire (EBW) detonators. (auth)

  6. Effect of disorder in the charge-density-wave compounds LaTe1.95 and CeTe1.95-xSex (x=0 and 0.16) as revealed by optical spectroscopy

    NASA Astrophysics Data System (ADS)

    Huang, Y.; Hu, B. F.; Dong, T.; Fang, A. F.; Zheng, P.; Wang, N. L.

    2012-11-01

    We present optical spectroscopy measurements on rare-earth ditelluride single crystals of LaTe1.95 and CeTe1.95-xSex (x=0 and 0.16). The measurements reveal formation of charge-density-wave energy gaps at rather high-energy levels, for example, 2Δ˜8500 cm-1 for LaTe1.95 and 6800 cm-1 for CeTe1.95. More strikingly, the study reveals that, different from the rare-earth tritellurides, the Te vacancies and disorder effect play a key role in the low-energy charge excitations of ditelluride systems. Although an eminent peak is observed between 800 and 1500 cm-1 in conductivity spectra for LaTe1.95, and CeTe1.95-xSex (x=0 and 0.16), our analysis indicates that it could not be attributed to the formation of a small energy gap, instead it could be well accounted for by the localization modified Drude model. Our study also indicates that the low-temperature optical spectroscopic features are distinctly different from a semiconducting charge-density-wave (CDW) state with entirely gapped Fermi surfaces.

  7. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

    1995-01-01

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

  8. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

    1995-08-29

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

  9. An artificial compound eye of photon Sieves

    NASA Astrophysics Data System (ADS)

    Jiang, Wenbo; Hu, Song; He, Yu; Bu, Yun

    2015-11-01

    The compound eye of insects has numerous extraordinary optical performances, such as minimum chromatic aberration, wide-angle field of view, and high sensitivity to the incidence light. Inspired by these unique performances, we present a novel artificial compound eye of photon sieves in this paper, where the photon sieves play the roles of insects' ommatidia. These photon sieves have the same focal length. The incidence light can be focused into the same focal plane and produce the superposition effect, the utilization ratio of energy can be largely improved. Through the numerical simulation, the results show that this novel structure has similar focusing performance with the conventional photon sieves, but has higher utilization ratio of energy and wider angle field of view than that of the conventional photon sieves. Our findings provide a new direction for optics and biology researchers, which will be beneficial for medical imaging, astronomy, etc.

  10. Optical microspectrometer

    DOEpatents

    Sweatt, William C.; Christenson, Todd R.

    2004-05-25

    An optical microspectrometer comprises a grism to disperse the spectra in a line object. A single optical microspectrometer can be used to sequentially scan a planar object, such as a dye-tagged microchip. Because the optical microspectrometer is very compact, multiple optical microspectrometers can be arrayed to provide simultaneous readout across the width of the planar object The optical microspectrometer can be fabricated with lithographic process, such as deep X-ray lithography (DXRL), with as few as two perpendicular exposures.

  11. Optically tunable optical filter

    NASA Astrophysics Data System (ADS)

    James, Robert T. B.; Wah, Christopher; Iizuka, Keigo; Shimotahira, Hiroshi

    1995-12-01

    We experimentally demonstrate an optically tunable optical filter that uses photorefractive barium titanate. With our filter we implement a spectrum analyzer at 632.8 nm with a resolution of 1.2 nm. We simulate a wavelength-division multiplexing system by separating two semiconductor laser diodes, at 1560 nm and 1578 nm, with the same filter. The filter has a bandwidth of 6.9 nm. We also use the same filter to take 2.5-nm-wide slices out of a 20-nm-wide superluminescent diode centered at 840 nm. As a result, we experimentally demonstrate a phenomenal tuning range from 632.8 to 1578 nm with a single filtering device.

  12. Photoinduced mass transport in azo compounds

    NASA Astrophysics Data System (ADS)

    Klismeta, K.; Teteris, J.; Aleksejeva, J.

    2013-12-01

    The photoinduced changes of optical properties in azobenzene containing compound thin films were studied under influence of polarized and non-polarized 532 nm laser light. Under influence of light azo compounds experience trans-cis isomerisation process, that can be observed in the absorbance spectrum of the sample. If the light is linearly polarized, molecules align perpendicularly to the electric field vector and as a result photoinduced dichroism and birefringence is obtained. If a known lateral polarization modulation of the light beam is present, mass transport of the azobenzene containing compound occurs. By measuring the surface relief with a profilometer the direction of mass transport can be determined. The studies of this work show that direct holographic recording of surface relief gratings can be used in optoelectronics, telecommunications and data storage.

  13. Study of the composition, structure, and optical properties of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket films erbium doped from the Er(pd){sub 3} complex compound

    SciTech Connect

    Kudoyarova, V. Kh. Tolmachev, V. A.; Gushchina, E. V.

    2013-03-15

    Rutherford backscattering, IR spectroscopy, ellipsometry, and atomic-force microscopy are used to perform an integrated study of the composition, structure and optical properties of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films. The technique employed to obtain the a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films includes the high-frequency decomposition of a mixture of gases, (SiH{sub 4}){sub a} + (CH{sub 4}){sub b}, and the simultaneous thermal evaporation of a complex compound, Er(pd){sub 3}. It is demonstrated that raising the amount of CH{sub 4} in the gas mixture results in an increase in the carbon content of the films under study and an increase in the optical gap E{sub g}{sup opt} from 1.75 to 2.2 eV. Changes in the composition of a-Si{sub 1-x}C{sub x}:H Left-Pointing-Angle-Bracket Er Right-Pointing-Angle-Bracket amorphous films, accompanied, in turn, by changes in the optical constants, are observed in the IR spectra. The ellipsometric spectra obtained are analyzed in terms of multiple-parameter models. The conclusion is made on the basis of this analysis that the experimental and calculated spectra coincide well when variation in the composition of the amorphous films with that of the gas mixture is taken into account. The existence of a thin (6-8 nm) silicon-oxide layer on the surface of the films under study and the validity of using the double-layer model in ellipsometric calculations is confirmed by the results of structural analyses by atomic-force microscopy.

  14. Process parameter optimization for hydantoinase-mediated synthesis of optically pure carbamoyl amino acids of industrial value using Pseudomonas aeruginosa resting cells.

    PubMed

    Engineer, Anupama S; Dhakephalkar, Anita P; Gaikaiwari, Raghavendra P; Dhakephalkar, Prashant K

    2013-12-01

    Hydantoinase-mediated enzymatic synthesis of optically pure carbamoyl amino acids was investigated as an environmentally friendly, energy-efficient alternative to the otherwise energy-intensive, polluting chemical synthesis. Hydantoinase-producing bacterial strain was identified as Pseudomonas aeruginosa by 16S rRNA gene sequencing and biochemical profiling using the BIOLOG Microbial Identification System. Hydantoinase activity was assessed using hydantoin analogs and 5-monosubstituted hydantoins as substrates in a colorimetric assay. The hydantoinase gene was PCR amplified using gene-specific primers and sequenced on an automated gene analyzer. Hydantoinase gene sequence of P. aeruginosa MCM B-887 revealed maximum homology of only 87 % with proven hydantoinase gene sequences in GenBank. MCM B-887 resting cells converted >99 % of substrate into N-carbamoyl amino acids under optimized condition at 42 °C, pH 8.0, and 100 mM substrate concentration in <120 min. Hydantoin hydrolyzing activity was D-selective and included broad substrate profile of 5-methyl hydantoin, 5-phenyl hydantoin, 5-hydroxyphenyl hydantoin, o-chlorophenyl hydantoin, as well as hydantoin analogs such as allantoin, dihydrouracil, etc. MCM B-887 resting cells may thus be suitable for bio-transformations leading to the synthesis of optically pure, unnatural carbamoyl amino acids of industrial importance. PMID:24065358

  15. Stabilized Lanthanum Sulphur Compounds

    NASA Technical Reports Server (NTRS)

    Reynolds, George H. (Inventor); Elsner, Norbert B. (Inventor); Shearer, Clyde H. (Inventor)

    1985-01-01

    Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium. or strontium. This novel compound is an excellent thermoelectric material.

  16. Heart testing compound

    DOEpatents

    Knapp, Jr., Furn F.; Goodman, Mark M.

    1985-01-01

    The compound 15-(p-[.sup.125 I]-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  17. Heart testing compound

    DOEpatents

    Knapp, F.F. Jr.; Goodman, M.M.

    1983-06-29

    The compound 15-(p-(/sup 125/I)-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  18. Anti-Fog Compound

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Tracer Chemical Corporation's TRX Anti-Fog Composition is an inexpensive product which prevents condensation on plastic and glass surfaces. It was the result from a Tech Briefs article detailing a Johnson Space Center compound.

  19. Optical to optical interface device

    NASA Technical Reports Server (NTRS)

    Oliver, D. S.; Vohl, P.; Nisenson, P.

    1972-01-01

    The development, fabrication, and testing of a preliminary model of an optical-to-optical (noncoherent-to-coherent) interface device for use in coherent optical parallel processing systems are described. The developed device demonstrates a capability for accepting as an input a scene illuminated by a noncoherent radiation source and providing as an output a coherent light beam spatially modulated to represent the original noncoherent scene. The converter device developed under this contract employs a Pockels readout optical modulator (PROM). This is a photosensitive electro-optic element which can sense and electrostatically store optical images. The stored images can be simultaneously or subsequently readout optically by utilizing the electrostatic storage pattern to control an electro-optic light modulating property of the PROM. The readout process is parallel as no scanning mechanism is required. The PROM provides the functions of optical image sensing, modulation, and storage in a single active material.

  20. Compounding a Problem?

    PubMed

    Berlin, Joey

    2016-01-01

    Allergist-immunologists say a U.S. Pharmacopeia proposal will mess with an allergy treatment system that's worked for more than a century. The revised standards, if adopted, would remove a key exemption separating allergen extract preparations from the stricter requirements of other compounds. Immunologists say the exemption has allowed them to compound allergen extracts in their own offices, and they've done so safely and effectively millions of times a year. PMID:27175928

  1. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  2. Compound composite odontoma

    PubMed Central

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas. PMID:27194882

  3. Compound composite odontoma.

    PubMed

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas. PMID:27194882

  4. Phenolic Molding Compounds

    NASA Astrophysics Data System (ADS)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  5. Understanding medication compounding issues.

    PubMed

    Hicks, Rodney W

    2014-04-01

    The potential for contamination of compounded products and the resulting infections are a serious threat to patient safety. Immediate use products are used frequently in the perioperative department, and perioperative nurses should be familiar with the guidelines and practices that aim to reduce the contamination that can occur during the sterile compounding process. Four common themes lead to successful compounding: quality (eg, product identification, purity, stability, compatibility, risk level assessment), the environment (eg, using a segregated compounding area with specialized airflow capabilities, reducing particulate matter, practicing proper hand hygiene, performing gloved fingertip sampling, properly cleaning equipment and work areas), personnel activities (eg, familiarity with types of containers used and how often they can be accessed, following expiration dates and the number of times containers can be accessed), and the control process (eg, process monitoring, quality improvement). If a third-party vendor is contracted to handle compounding for a facility, perioperative personnel should be aware of the responsibilities for the facility and the vendor to ensure a quality compounding program. PMID:24674793

  6. Optical probe

    DOEpatents

    Hencken, Kenneth; Flower, William L.

    1999-01-01

    A compact optical probe is disclosed particularly useful for analysis of emissions in industrial environments. The instant invention provides a geometry for optically-based measurements that allows all optical components (source, detector, rely optics, etc.) to be located in proximity to one another. The geometry of the probe disclosed herein provides a means for making optical measurements in environments where it is difficult and/or expensive to gain access to the vicinity of a flow stream to be measured. Significantly, the lens geometry of the optical probe allows the analysis location within a flow stream being monitored to be moved while maintaining optical alignment of all components even when the optical probe is focused on a plurality of different analysis points within the flow stream.

  7. Optical Communications

    ERIC Educational Resources Information Center

    Young, Matt

    1973-01-01

    Describes the characteristics and operational problems of optical waveguides, and concludes that the wide use of optical communications can be expected if difficulties in commercial production of components can be eliminated. (CC)

  8. Optical keyboard

    DOEpatents

    Veligdan, James T.; Feichtner, John D.; Phillips, Thomas E.

    2001-01-01

    An optical keyboard includes an optical panel having optical waveguides stacked together. First ends of the waveguides define an inlet face, and opposite ends thereof define a screen. A projector transmits a light beam outbound through the waveguides for display on the screen as a keyboard image. A light sensor is optically aligned with the inlet face for sensing an inbound light beam channeled through the waveguides from the screen upon covering one key of the keyboard image.

  9. Synthesizing Diacetylenes With Nonlinear Optical Properties

    NASA Technical Reports Server (NTRS)

    Mcmanus, Samuel P.; Frazier, Donald P.; Paley, Mark S.

    1993-01-01

    Diacetylene compounds being investigated to determine whether they have nonlinear optical properties making them useful for four-wave mixing, generation of third harmonics, phase conjugation, and like. Diacetylene monomers synthesized by sequences of chemical reactions. Monomers polymerized by ultraviolet light, forming potentially useful nonlinear optical materials.

  10. Manufacturing: 3D printed micro-optics

    NASA Astrophysics Data System (ADS)

    Juodkazis, Saulius

    2016-08-01

    Uncompromised performance of micro-optical compound lenses has been achieved by high-fidelity shape definition during two-photon absorption microfabrication. The lenses have been made directly onto image sensors and even onto the tip of an optic fibre.

  11. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  12. Optical set-reset latch

    DOEpatents

    Skogen, Erik J.

    2013-01-29

    An optical set-reset (SR) latch is formed from a first electroabsorption modulator (EAM), a second EAM and a waveguide photodetector (PD) which are arranged in an optical and electrical feedback loop which controls the transmission of light through the first EAM to latch the first EAM in a light-transmissive state in response to a Set light input. A second waveguide PD controls the transmission of light through the second EAM and is used to switch the first EAM to a light-absorptive state in response to a Reset light input provided to the second waveguide PD. The optical SR latch, which may be formed on a III-V compound semiconductor substrate (e.g. an InP or a GaAs substrate) as a photonic integrated circuit (PIC), stores a bit of optical information and has an optical output for the logic state of that bit of information.

  13. Diphenylpolyynes For Nonlinear Optical Devices

    NASA Technical Reports Server (NTRS)

    Stiegman, Albert E.; Perry, Joseph W.; Coulter, Daniel R.

    1989-01-01

    Several diphenylpolyyne compounds found to exhibit second-order nonlinear electric susceptibilities and chemical structures conducive to orientation in appropriate chemical environments. These features make new materials suitable for use in optical devices. Diphenylacetylene links give molecules rodlike characteristics making them amenable to orientation by suspension in liquid crystals. New molecules also have inherent liquid-crystalline properties enabling them to be oriented directly.

  14. Nonlinear optical properties of bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Hendrickx, Eric; Verbiest, Thierry; Clays, Koen J.; Persoons, Andre P.

    1993-04-01

    In this paper we show the applicability of Hyper-Rayleigh scattering to obtain hyperpolarizabilities of ionic and biochemical compounds. It was found that dark-adapted bacteriorhodopsin and its isolated chromophore have considerable second order nonlinear optical properties. Information obtained from depolarization studies of the scattered light is discussed.

  15. Optical Micromachining

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Under an SBIR (Small Business Innovative Research) with Marshall Space Flight Center, Potomac Photonics, Inc., constructed and demonstrated a unique tool that fills a need in the area of diffractive and refractive micro-optics. It is an integrated computer-aided design and computer-aided micro-machining workstation that will extend the benefits of diffractive and micro-optic technology to optical designers. Applications of diffractive optics include sensors and monitoring equipment, analytical instruments, and fiber optic distribution and communication. The company has been making diffractive elements with the system as a commercial service for the last year.

  16. Optical Tweezers

    NASA Astrophysics Data System (ADS)

    Jones, Philip H.; Maragò, Onofrio M.; Volpe, Giovanni

    2015-12-01

    1. Introduction; Part I. Theory: 2. Ray optics; 3. Dipole approximation; 4. Optical beams and focusing; 5. Electromagnetic theory; 6. Computational methods; 7. Brownian motion; Part II. Practice: 8. Building an optical tweezers; 9. Data acquisition and optical tweezers calibration; 10. Photonic force microscope; 11. Wavefront engineering and holographic optical tweezers; 12. Advanced techniques; Part III. Applications: 13. Single molecule biophysics; 14. Cell biology; 15. Spectroscopy; 16. Optofluidics and lab on a chip; 17. Colloid science; 18. Microchemistry; 19. Aerosol science; 20. Statistical physics; 21. Nanothermodynamics; 22. Plasmonics; 23. Nanostructures; 24. Laser cooling and trapping of atoms; 25. Towards the quantum regime at the mesoscale; Index.

  17. Spin state switching in iron coordination compounds

    PubMed Central

    Gaspar, Ana B; Garcia, Yann

    2013-01-01

    Summary The article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices. The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligo- and polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property. PMID:23504535

  18. Compound management beyond efficiency.

    PubMed

    Burr, Ian; Winchester, Toby; Keighley, Wilma; Sewing, Andreas

    2009-06-01

    Codeveloping alongside chemistry and in vitro screening, compound management was one of the first areas in research recognizing the need for efficient processes and workflows. Material management groups have centralized, automated, miniaturized and, importantly, found out what not to do with compounds. While driving down cost and improving quality in storage and processing, researchers still face the challenge of interfacing optimally with changing business processes, in screening groups, and with external vendors and focusing on biologicals in many companies. Here we review our strategy to provide a seamless link between compound acquisition and screening operations and the impact of material management on quality of the downstream processes. Although this is driven in part by new technologies and improved quality control within material management, redefining team structures and roles also drives job satisfaction and motivation in our teams with a subsequent positive impact on cycle times and customer feedback. PMID:19502566

  19. Sulfur compounds in coal

    NASA Technical Reports Server (NTRS)

    Attar, A.; Corcoran, W. H.

    1977-01-01

    The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

  20. Metalloid compounds as drugs

    PubMed Central

    Sekhon, B. S.

    2013-01-01

    The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O’-)tellurate (AS101) may be a promising agent for the treatment of Parkinson’s disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

  1. Self-assembly micro optical filter

    NASA Astrophysics Data System (ADS)

    Zhang, Ping (Cerina); Le, Kevin; Malalur-Nagaraja-Rao, Smitha; Hsu, Lun-Chen; Chiao, J.-C.

    2006-01-01

    Optical communication and sensor industry face critical challenges in manufacturing for system integration. Due to the assembly complexity and integration platform variety, micro optical components require costly alignment and assembly procedures, in which many required manual efforts. Consequently, self-assembly device architectures have become a great interest and could provide major advantages over the conventional optical devices. In this paper, we discussed a self-assembly integration platform for micro optical components. To demonstrate the adaptability and flexibility of the proposed optical device architectures, we chose a commercially available MEMS fabrication foundry service - MUMPs (Multi-User MEMS Process). In this work, polysilicon layers of MUMPS are used as the 3-D structural material for construction of micro component framework and actuators. However, because the polysilicon has high absorption in the visible and near infrared wavelength ranges, it is not suitable for optical interaction. To demonstrate the required optical performance, hybrid integration of materials was proposed and implemented. Organic compound materials were applied on the silicon-based framework to form the required optical interfaces. Organic compounds provide good optical transparency, flexibility to form filters or lens and inexpensive manufacturing procedures. In this paper, we have demonstrated a micro optical filter integrated with self-assembly structures. We will discuss the self-assembly mechanism, optical filter designs, fabrication issues and results.

  2. Nonlinear optical studies of a novel pyrazoline

    NASA Astrophysics Data System (ADS)

    Janardhana, K.; Ravindrachary, V.; Kumar, P. C. Rajesh; Umesh, G.; Manjunatha, K. B.; Ismayil

    2012-06-01

    A novel pyrazoline, 3-(phenyl)-5-(4-hydroxyphenyl)-1-(2, 4-dinitrophenyl)-2-pyrazoline (PHDP) was synthesized using standard method and its chemical structure was confirmed using FTIR studies. The linear and non linear optical properties of the compound were studied using UV-Vis and Z-scan techniques. UV-Vis spectrum shows that the compound is transparent in the visible region and absorption in the UV region. The z-scan study shows that the compound possesses third and higher order optical nonlinearity. The calculated optical absorption cross sections indicate that the operating nonlinear mechanism is reverse saturable absorption type. The real part of the third-order nonlinear optical susceptibility χ3 was estimated and the closed aperture data shows that PHDP possess negative nonlinearity.

  3. Multifunctional organoboron compounds for scalable natural product synthesis.

    PubMed

    Meng, Fanke; McGrath, Kevin P; Hoveyda, Amir H

    2014-09-18

    Efficient catalytic reactions that can generate C-C bonds enantioselectively, and ones that can produce trisubstituted alkenes diastereoselectively, are central to research in organic chemistry. Transformations that accomplish these two tasks simultaneously are in high demand, particularly if the catalysts, substrates and reagents are inexpensive and if the reaction conditions are mild. Here we report a facile multicomponent catalytic process that begins with a chemoselective, site-selective and diastereoselective copper-boron addition to a monosubstituted allene; the resulting boron-substituted organocopper intermediates then participate in a similarly selective allylic substitution. The products, which contain a stereogenic carbon centre, a monosubstituted alkene and an easily functionalizable Z-trisubstituted alkenylboron group, are obtained in up to 89 per cent yield, with more than 98 per cent branch-selectivity and stereoselectivity and an enantiomeric ratio greater than 99:1. The copper-based catalyst is derived from a robust heterocyclic salt that can be prepared in multigram quantities from inexpensive starting materials and without costly purification procedures. The utility of the approach is demonstrated through enantioselective synthesis of gram quantities of two natural products, namely rottnestol and herboxidiene (also known as GEX1A). PMID:25230659

  4. Multifunctional organoboron compounds for scalable natural product synthesis

    NASA Astrophysics Data System (ADS)

    Meng, Fanke; McGrath, Kevin P.; Hoveyda, Amir H.

    2014-09-01

    Efficient catalytic reactions that can generate C-C bonds enantioselectively, and ones that can produce trisubstituted alkenes diastereoselectively, are central to research in organic chemistry. Transformations that accomplish these two tasks simultaneously are in high demand, particularly if the catalysts, substrates and reagents are inexpensive and if the reaction conditions are mild. Here we report a facile multicomponent catalytic process that begins with a chemoselective, site-selective and diastereoselective copper-boron addition to a monosubstituted allene; the resulting boron-substituted organocopper intermediates then participate in a similarly selective allylic substitution. The products, which contain a stereogenic carbon centre, a monosubstituted alkene and an easily functionalizable Z-trisubstituted alkenylboron group, are obtained in up to 89 per cent yield, with more than 98 per cent branch-selectivity and stereoselectivity and an enantiomeric ratio greater than 99:1. The copper-based catalyst is derived from a robust heterocyclic salt that can be prepared in multigram quantities from inexpensive starting materials and without costly purification procedures. The utility of the approach is demonstrated through enantioselective synthesis of gram quantities of two natural products, namely rottnestol and herboxidiene (also known as GEX1A).

  5. Urinary Compounds in Autism

    ERIC Educational Resources Information Center

    Alcorn, A.; Berney, T.; Bretherton, K.; Mills, M.; Savery, D.; Shattock, P.

    2004-01-01

    Although earlier claims to identify specific compounds in the urine of people with autism had been discredited, it was subsequently suggested that there might be biochemical characteristics that were specific to early childhood, particularly in those who also did not have a severe degree of intellectual disability This study was to establish…

  6. Aminopropyl thiophene compounds

    SciTech Connect

    Goodman, M.M.; Knapp, F.F.

    1990-04-03

    This patent describes radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain.

  7. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  8. The Onium Compounds

    NASA Astrophysics Data System (ADS)

    Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri

    1997-06-01

    The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.

  9. Analyzing cranberry bioactive compounds.

    PubMed

    Côté, J; Caillet, S; Doyon, G; Sylvain, J-F; Lacroix, M

    2010-10-01

    There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit--the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a sample matrix is a prerequisite to any comprehensive analysis scheme. By far the most widely employed analytical technique for the characterization of these compounds has been high-performance liquid chromatography(HPLC) coupled with ultraviolet-visible(UV/Vis) and mass spectrometer(MS) detection. This review covers the cranberry major bioactive compounds, the extraction and purification methods, and the analytical conditions for HPLC used to characterize them. Extraction, chromatographic separation and detection strategies, analyte determinations, and applications in HPLC are discussed and the information regarding methods of specific cranberry analyte analyses has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader. PMID:20924868

  10. Aminopropyl thiophene compounds

    DOEpatents

    Goodman, Mark M.; Knapp, Jr., Furn F.

    1990-01-01

    Radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain.

  11. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  12. Zinc and Compounds

    Integrated Risk Information System (IRIS)

    Zinc and Compounds ; CASRN 7440 - 66 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogen

  13. Boron and Compounds

    Integrated Risk Information System (IRIS)

    Boron and Compounds ; CASRN 7440 - 42 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  14. Lead and compounds (inorganic)

    Integrated Risk Information System (IRIS)

    Lead and compounds ( inorganic ) ; CASRN 7439 - 92 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  15. Barium and Compounds

    Integrated Risk Information System (IRIS)

    Barium and Compounds ; CASRN 7440 - 39 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  16. Beryllium and compounds

    Integrated Risk Information System (IRIS)

    Beryllium and compounds ; CASRN 7440 - 41 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  17. Selenium and Compounds

    Integrated Risk Information System (IRIS)

    Selenium and Compounds ; CASRN 7782 - 49 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  18. 8-fluoropurine compounds

    DOEpatents

    Barrio, Jorge R.; Satyamurthy, Nagichettiar; Namavari, Mohammad; Phelps, Michael E.

    2001-01-01

    An efficient, regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F.sub.2 in He or other inert gas.

  19. Noun Compounding in Thai.

    ERIC Educational Resources Information Center

    Fasold, Ralph William August

    The present study, a slightly revised version of the author's 1968 Ph.D. thesis presented to the University of Chicago, investigates compound formation in Thai. Chapter 1 summarizes the transformational generative theory on which the study is based, discusses the concept that Thai is a "simple" language in comparison with English, and briefly…

  20. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J.

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  1. Natural compounds in the synthesis of chiral organophosphorous ligands

    NASA Astrophysics Data System (ADS)

    Tolstikov, Alexander G.; Khlebnikova, Tatiana B.; Tolstikova, Olga V.; Tolstikov, Genrikh A.

    2003-09-01

    Methods for the synthesis of chiral organophosphorus compounds based on natural optically active compounds (hydroxy acids, amino acids and their derivatives, mono- and disaccharides, mono- and diterpenoids, steroids) are discussed. Particular attention is given to the synthesis of bisphosphines and bisphosphinites. These compounds serve as ligands for transition metal complexes, which catalyse asymmetric hydrogenation. Data on the enantioselectivity of hydrogenation of unsaturated precursors of amino acids and unsaturated prochiral acids as well as on information on the enantioselectivity of hydrosilylation of ketones are surveyed.

  2. COMPU-EYE: a high resolution computational compound eye.

    PubMed

    Lee, Woong-Bi; Jang, Hwanchol; Park, Sangjun; Song, Young Min; Lee, Heung-No

    2016-02-01

    In nature, the compound eyes of arthropods have evolved towards a wide field of view (FOV), infinite depth of field and fast motion detection. However, compound eyes have inferior resolution when compared with the camera-type eyes of vertebrates, owing to inherent structural constraints such as the optical performance and the number of ommatidia. For resolution improvements, in this paper, we propose COMPUtational compound EYE (COMPU-EYE), a new design that increases acceptance angles and uses a modern digital signal processing (DSP) technique. We demonstrate that the proposed COMPU-EYE provides at least a four-fold improvement in resolution. PMID:26906778

  3. Synthesis, spectroscopic characteristic of novel fluorescent dyes of pyrazoline compounds

    NASA Astrophysics Data System (ADS)

    Wang, Hai-Ying; Zhang, Xiao-Xiao; Shi, Jing-Jing; Chen, Gang; Xu, Xiao-Ping; Ji, Shun-Jun

    Four novel fluorescence dyes of the pyrazoline were synthesized and fully characterized by means of 1H, 13C NMR, and HRMS. The optical, electrochemical properties were also investigated. Solvent effect on the fluorescence characteristics of the four compounds indicates that the emission wavelength was red-shifted with the increase of solvent polarity. As we expected, the results indicated that these compounds exhibited high quantum yields. Quantum chemical calculations were used to obtain optimized ground-state geometry, spatial distributions of the HOMO, LUMO levels of the compounds.

  4. Geometrical Optics

    NASA Astrophysics Data System (ADS)

    Lindlein, Norbert; Leuchs, Gerd

    This chapter shall discuss the basics and the applications of geometrical optical methods in modern optics. Geometrical optics has a long tradition and some ideas are many centuries old. Nevertheless, the invention of modern personal computers which can perform several million floating-point operations in a second also revolutionized the methods of geometrical optics and so several analytical methods lost importance whereas numerical methods such as ray tracing became very important. Therefore, the emphasis in this chapter is also on modern numerical methods such as ray tracing and some other systematic methods such as the paraxial matrix theory.

  5. Optical computing.

    NASA Technical Reports Server (NTRS)

    Stroke, G. W.

    1972-01-01

    Applications of the optical computer include an approach for increasing the sharpness of images obtained from the most powerful electron microscopes and fingerprint/credit card identification. The information-handling capability of the various optical computing processes is very great. Modern synthetic-aperture radars scan upward of 100,000 resolvable elements per second. Fields which have assumed major importance on the basis of optical computing principles are optical image deblurring, coherent side-looking synthetic-aperture radar, and correlative pattern recognition. Some examples of the most dramatic image deblurring results are shown.

  6. Optical trapping

    PubMed Central

    Neuman, Keir C.; Block, Steven M.

    2006-01-01

    Since their invention just over 20 years ago, optical traps have emerged as a powerful tool with broad-reaching applications in biology and physics. Capabilities have evolved from simple manipulation to the application of calibrated forces on—and the measurement of nanometer-level displacements of—optically trapped objects. We review progress in the development of optical trapping apparatus, including instrument design considerations, position detection schemes and calibration techniques, with an emphasis on recent advances. We conclude with a brief summary of innovative optical trapping configurations and applications. PMID:16878180

  7. QUANTUM OPTICS. Universal linear optics.

    PubMed

    Carolan, Jacques; Harrold, Christopher; Sparrow, Chris; Martín-López, Enrique; Russell, Nicholas J; Silverstone, Joshua W; Shadbolt, Peter J; Matsuda, Nobuyuki; Oguma, Manabu; Itoh, Mikitaka; Marshall, Graham D; Thompson, Mark G; Matthews, Jonathan C F; Hashimoto, Toshikazu; O'Brien, Jeremy L; Laing, Anthony

    2015-08-14

    Linear optics underpins fundamental tests of quantum mechanics and quantum technologies. We demonstrate a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons, and their measurement with a 12-single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with an average fidelity of 0.999 ± 0.001. Our system can be rapidly reprogrammed to implement these and any other linear optical protocol, pointing the way to applications across fundamental science and quantum technologies. PMID:26160375

  8. Intercalation compounds involving inorganic layered structures

    PubMed

    Constantino; Barbosa; Bizeto; Dias

    2000-01-01

    Two-dimensional inorganic networks can shown intracrystalline reactivity, i.e., simple ions, large species as Keggin ions, organic species, coordination compounds or organometallics can be incorporated in the interlayer region. The host-guest interaction usually causes changes in their chemical, catalytic, electronic and optical properties. The isolation of materials with interesting properties and making use of soft chemistry routes have given rise the possibility of industrial and technological applications of these compounds. We have been using several synthetic approaches to intercalate porphyrins and phthalocyanines into inorganic materials: smectite clays, layered double hydroxides and layered niobates. The isolated materials have been characterized by elemental and thermal analysis, X-ray diffraction, surface area measurements, scanning electronic microscopy, electronic and resonance Raman spectroscopies and EPR. The degree of layer stacking and the charge density of the matrices as well their acid-base nature were considered in our studies on the interaction between the macrocycles and inorganic hosts. PMID:10932103

  9. Optical testing

    NASA Technical Reports Server (NTRS)

    Wyant, James; Hochberg, Eric; Breault, Robert; Greivenkamp, John; Hunt, Gary; Mason, Pete; Mcguire, James; Meinel, Aden; Morris, Mike; Scherr, Larry

    1992-01-01

    Optical testing is one of the most vital elements in the process of preparing an optical instrument for launch. Without well understood, well controlled, and well documented test procedures, current and future mission goals will be jeopardized. We should keep in mind that the reason we test is to provide an opportunity to catch errors, oversights, and problems on the ground, where solutions are possible and difficulties can be rectified. Consequently, it is necessary to create tractable test procedures that truly provide a measure of the performance of all optical elements and systems under conditions which are close to those expected in space. Where testing is not feasible, accurate experiments are required in order to perfect models that can exactly predict the optical performance. As we stretch the boundaries of technology to perform more complex space and planetary investigations, we must expand the technology required to test the optical components and systems which we send into space. As we expand the observational wavelength ranges, so must we expand our range of optical sources and detectors. As we increase resolution and sensitivity, our understanding of optical surfaces to accommodate more stringent figure and scatter requirements must expand. Only with research and development in these areas can we hope to achieve success in the ever increasing demands made on optical testing by the highly sophisticated missions anticipated over the next two decades. Technology assessment and development plan for surface figure, surface roughness, alignment, image quality, radiometric quantities, and stray light measurement are presented.

  10. Optical Disks.

    ERIC Educational Resources Information Center

    Gale, John C.; And Others

    1985-01-01

    This four-article section focuses on information storage capacity of the optical disk covering the information workstation (uses microcomputer, optical disk, compact disc to provide reference information, information content, work product support); use of laser videodisc technology for dissemination of agricultural information; encoding databases…

  11. Optical Detectors

    NASA Astrophysics Data System (ADS)

    Tabbert, Bernd; Goushcha, Alexander

    Optical detectors are applied in all fields of human activities from basic research to commercial applications in communication, automotive, medical imaging, homeland security, and other fields. The processes of light interaction with matter described in other chapters of this handbook form the basis for understanding the optical detectors physics and device properties.

  12. Arsonium compounds in algae

    PubMed Central

    Benson, A. A.

    1989-01-01

    Search for a precursor of the arsenobetaine discovered in Western Australian rock lobster tail muscle has led to an algal metabolite of radioarsenate having the properties of a trimethylarsoniumriboside derivative of the major arsenicals of aquatic plants, dimethylarsinoylribosylglycerol, its sulfate ester, and the corresponding riboside of phosphatidylglycerol. Such an arsonium compound could serve as metabolic precursor of arsenobetaine, the innocuous arsenical component of many marine food products. The oceanic diatom, Chaetoceros gracilis, cultured in radioarsenate produced a compound whose chemical, chromatographic, and electrophoretic properties are described. It was found to be identical to the trimethylarsonium derivative synthesized from the major algal arsenical, 1-(5′-dimethylarsinoyl-5′-deoxyribosyl)glycerol-3-O -sulfate. PMID:16594059

  13. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.

    1980-01-01

    Recent studies of carbonaceous chondrites provide evidence that certain organic compounds are indigenous and the result of an abiotic, chemical synthesis. The results of several investigators have established the presence of amino acids and precursors, mono- and dicarboxylic acids, N-heterocycles, and hydrocarbons as well as other compounds. For example, studies of the Murchison and Murray meteorites have revealed the presence of at least 40 amino acids with nearly equal abundances of D and L isomers. The population consists of both protein and nonprotein amino acids including a wide variety of linear, cyclic, and polyfunctional types. Results show a trend of decreasing concentration with increasing carbon number, with the most abundant being glycine (41 n Moles/g). These and other results to be reviewed provide persuasive support for the theory of chemical evolution and provide the only natural evidence for the protobiological subset of molecules from which life on earth may have arisen.

  14. Photofunctions of intercalation compounds

    SciTech Connect

    Ogawa, Makoto; Kuroda, Kazuyuki

    1995-03-01

    In this article, the authors review the studies on the photofunctions of intercalation compounds. (The structures and properties of host materials which have been used for immobilizing photoactive species have been summarized in the following section.) some of these studies are for the purpose of characterizing the properties of host materials and host-guest systems, and others are for the purpose of contributing to future practical applications. The well-defined layered structures as well as the ability to accommodate guest species on the surface of the layers are very useful for organizing photoactive species to evaluate and control the photofunctions. Table 1 summarizes the characteristics of typical host-guest systems studied for immobilizing photoactive species. Attention is mainly focused on the role of layered structure on the organization of photoactive species; the photofunctions of intercalation compounds are discussed only in connection with the microscopic structures. 321 refs.

  15. Optical biosensors

    PubMed Central

    Damborský, Pavel; Švitel, Juraj

    2016-01-01

    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. PMID:27365039

  16. Optical biosensors.

    PubMed

    Damborský, Pavel; Švitel, Juraj; Katrlík, Jaroslav

    2016-06-30

    Optical biosensors represent the most common type of biosensor. Here we provide a brief classification, a description of underlying principles of operation and their bioanalytical applications. The main focus is placed on the most widely used optical biosensors which are surface plasmon resonance (SPR)-based biosensors including SPR imaging and localized SPR. In addition, other optical biosensor systems are described, such as evanescent wave fluorescence and bioluminescent optical fibre biosensors, as well as interferometric, ellipsometric and reflectometric interference spectroscopy and surface-enhanced Raman scattering biosensors. The optical biosensors discussed here allow the sensitive and selective detection of a wide range of analytes including viruses, toxins, drugs, antibodies, tumour biomarkers and tumour cells. PMID:27365039

  17. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  18. Antifungal Compounds from Cyanobacteria

    PubMed Central

    Shishido, Tânia K.; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P.; Permi, Perttu; Andreote, Ana P. D.; Fiore, Marli F.; Sivonen, Kaarina

    2015-01-01

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders. PMID:25871291

  19. Compound chondrules fused cold

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2015-07-01

    About 4-5% of chondrules are compound: two separate chondrules stuck together. This is commonly believed to be the result of the two component chondrules having collided shortly after forming, while still molten. This allows high velocity impacts to result in sticking. However, at T ∼ 1100 K, the temperature below which chondrules collide as solids (and hence usually bounce), coalescence times for droplets of appropriate composition are measured in tens of seconds. Even at 1025 K, at which temperature theory predicts that the chondrules must have collided extremely slowly to have stuck together, the coalescence time scale is still less than an hour. These coalescence time scales are too short for the collision of molten chondrules to explain the observed frequency of compound chondrules. We suggest instead a scenario where chondrules stuck together in slow collisions while fully solid; and the resulting chondrule pair was subsequently briefly heated to a temperature in the range of 900-1025 K. In that temperature window the coalescence time is finite but long, covering a span of hours to a decade. This is particularly interesting because those temperatures are precisely the critical window for thermally ionized MRI activity, so compound chondrules provide a possible probe into that vital regime.

  20. Toxic compounds in honey.

    PubMed

    Islam, Md Nazmul; Khalil, Md Ibrahim; Islam, Md Asiful; Gan, Siew Hua

    2014-07-01

    There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food. PMID:24214851

  1. Broadband optical modulators based on graphene supercapacitors.

    PubMed

    Polat, Emre O; Kocabas, Coskun

    2013-01-01

    Optical modulators are commonly used in communication and information technology to control intensity, phase, or polarization of light. Electro-optic, electroabsorption, and acousto-optic modulators based on semiconductors and compound semiconductors have been used to control the intensity of light. Because of gate tunable optical properties, graphene introduces new potentials for optical modulators. The operation wavelength of graphene-based modulators, however, is limited to infrared wavelengths due to inefficient gating schemes. Here, we report a broadband optical modulator based on graphene supercapacitors formed by graphene electrodes and electrolyte medium. The transparent supercapacitor structure allows us to modulate optical transmission over a broad range of wavelengths from 450 nm to 2 μm under ambient conditions. We also provide various device geometries including multilayer graphene electrodes and reflection type device geometries that provide modulation of 35%. The graphene supercapacitor structure together with the high-modulation efficiency can enable various active devices ranging from plasmonics to optoelectronics. PMID:24215484

  2. IRIS Toxicological Review of Thallium and Compounds (External Review Draft)

    EPA Science Inventory

    Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certai...

  3. Gauges for Highly Precise Metrology of a Compound Mirror

    NASA Technical Reports Server (NTRS)

    Gursel, Yekta

    2005-01-01

    Three optical gauges have been developed for guiding the assembly and measuring precisely the reflecting surfaces of a compound mirror that comprises a corner-cube retroreflector glued in a hole on a flat mirror. In the specific application for which the gauges were developed, the compound mirror is part of a siderostat in a stellar interferometer. The flat-mirror portion of the compound mirror is the siderostat mirror; the retroreflector portion of the compound mirror is to be used, during operation of the interferometer, to monitor the location of the siderostat mirror surface relative to other optical surfaces of the interferometer. Nominally, the optical corner of the retroreflector should lie precisely on the siderostat mirror surface, but this precision cannot be achieved in fabrication: in practice, there remains some distance between the optical corner and the siderostat mirror surface. For proper operation of the interferometer, it is required to make this distance as small as possible and to know this distance within 1 nm. The three gauges make it possible to satisfy these requirements.

  4. Fiber optic coupled optical sensor

    DOEpatents

    Fleming, Kevin J.

    2001-01-01

    A displacement sensor includes a first optical fiber for radiating light to a target, and a second optical fiber for receiving light from the target. The end of the first fiber is adjacent and not axially aligned with the second fiber end. A lens focuses light from the first fiber onto the target and light from the target onto the second fiber.

  5. Differential two-body compound nuclear cross section, including the width-fluctuation corrections

    SciTech Connect

    Brown, D.; Herman, M.

    2014-09-02

    We figure out the compound angular differential cross sections, following mainly Fröbrich and Lipperheide, but with the angular momentum couplings that make sense for optical model work. We include the width-fluctuation correction along with calculations.

  6. Optical photopolymers

    SciTech Connect

    Weber, A.M.

    1995-12-01

    The ability to manipulate light is becoming increasingly important in electronics, communications and automotive applications. Advanced materials are often necessary to efficiently harness and transform light into useful information, visual imagery and/or energy. DuPont is currently developing a family of optical photopolymers, OmniDex{reg_sign} holographic recording materials, waveguide materials for Polyguide{trademark} integrated optic technology, and Surphex{trademark} photopolymer embossable films. When properly imaged with light these materials form optical devices. The material properties and mechanism by which images and devices are recorded will be discussed along with process of use. Applications will also be highlighted.

  7. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  8. Special Risks of Pharmacy Compounding

    MedlinePlus

    ... Consumer Updates RSS Feed The Special Risks of Pharmacy Compounding Get Consumer Updates by E-mail Consumer ... page: A Troubling Trend What You Can Do Pharmacy compounding is a practice in which a licensed ...

  9. Oligosilanylated Antimony Compounds

    PubMed Central

    2015-01-01

    By reactions of magnesium oligosilanides with SbCl3, a number of oligosilanylated antimony compounds were obtained. When oligosilanyl dianions were used, either the expected cyclic disilylated halostibine was obtained or alternatively the formation of a distibine was observed. Deliberate formation of the distibine from the disilylated halostibine was achieved by reductive coupling with C8K. Computational studies of Sb–Sb bond energies, barriers of pyramidal inversion at Sb, and the conformational behavior of distibines provided insight for the understanding of the spectroscopic properties. PMID:25937691

  10. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  11. Immunomodulating compounds in Basidiomycetes

    PubMed Central

    Mizuno, Masashi; Nishitani, Yosuke

    2013-01-01

    Mushrooms are distinguished as important food containing immunomodulating and anticancer agents. These compounds belong mostly to polysaccharides especially β-d-glucans. Among them, β-1,3-glucan with side chain β-1,6-glucose residues have more important roles in immunomodulating and antitumor activities. In this review, we have introduced polysaccharide mainly from Lentinula edodes and Agaricus blazei Murill with immunomodulating and antitumor activities. In addition, the mechanism of activation of immune response and signal cascade are also reviewed. PMID:23704809

  12. Boronated porphyrin compounds

    DOEpatents

    Kahl, Stephen B.; Koo, Myoung-Seo

    1992-01-01

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  13. Boronated porphyrin compounds

    DOEpatents

    Kahl, S.B.; Koo, M.S.

    1992-09-22

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  14. Turbo compound engine

    SciTech Connect

    Okada, M.; Sekiyama, S.

    1988-06-07

    A turbo compound engine is described comprising: an engine having an exhaust gas passage and a crankshaft; a power turbine disposed in the exhaust gas passage so as to recover the exhaust gas energy; driving power transmission means for drivingly connecting the power turbine and the crankshaft so as to transmit the driving power; a fluid passage connected to a portion of the exhaust passage which lies between the power turbine and the engine; and fluid passage switching means for closing the exhaust passage upstream of the fluid passage while opening the fluid passage during exhaust braking.

  15. Compound allergy. An overview.

    PubMed

    Bashir, S J; Maibach, H I

    1997-04-01

    This review defines the term "compound allergy" in the context of new findings, and discusses evidence that allergenic reaction products have been identified. Material was gathered by searching Index Medicus and the Science Citation Index, and reviewing several standard texts. Issues regarding the validity of patch test results are addressed and we introduce the term "pseudocompound allergy" to cover cases of false-negative patch tests. We present new theories regarding the mechanisms by which new allergens are formed and a means of classification. PMID:9165199

  16. Optic glioma

    MedlinePlus

    ... et al. Optic Glioma in Children: A Retrospective Analysis of 101 Cases. American Journal of Clinical Oncology. 2013; 36(3):287-292. Karcioglu ZA, Haik BG. Eye, orbit, and adnexal structures. In: Abeloff MD, Armitage JO, ...

  17. Bio-inspired Artificial Apposition Compound Eye

    NASA Astrophysics Data System (ADS)

    Xiao, Jianliang; Song, Youngmin; Xie, Yizhu; Malyarchuk, Viktor; Huang, Yonggang; Rogers, John

    2014-03-01

    In arthropods, evolution has created a remarkably sophisticated class of imaging system, with wide angle field of view, low aberrations, high acuity to motion and infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot be met with existing planar sensor technologies or conventional optics. We present ideas in materials, mechanics and integration schemes that enable scalable pathways to working, arthropod-inspired cameras in nearly full hemispherical shapes with surfaces densely populated by imaging elements (i.e. artificial ommatidia). The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors, in co-integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated, to hemispherical shapes for integration into apposition cameras. Experimental and theoretical studies reveal key aspects of the materials science and physics of these systems. Imaging results and quantitative ray-tracing based modeling illustrate essential features of their operation.

  18. Organometallic chemistry of bimetallic compounds

    SciTech Connect

    Casey, C.P.

    1991-07-01

    This report consists of six sections: heterobimetallic dihydrides, early-late transition metal heterobimetallic compounds, amphiphilic carbene complexes and hydroxycarbene complexes, diiron compounds with bridging hydrocarbon ligands, diphosphine chelates with natural bite angles near 120 degrees, and synthesis and reactions of M=M compounds. (WET)

  19. Isolation of bioactive biphenyl compounds from the twigs of Chaenomeles sinensis.

    PubMed

    Kim, Chung Sub; Subedi, Lalita; Kwon, Oh Kil; Kim, Sun Yeou; Yeo, Eui-Ju; Choi, Sang Un; Lee, Kang Ro

    2016-01-15

    Investigation of the MeOH extract of Chaenomeles sinensis twigs resulted in the isolation of seven biphenyl compounds (1-7) including a new compound, chaenomin (1). The chemical structures of the isolated compounds were elucidated by extensive NMR data ((1)H and (13)C NMR, (1)H-(1)H COSY, HSQC and HMBC), specific optical rotation, and chemical reaction. Compounds 2 and 6 showed potent cytotoxic activities against four cancer cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15), and compound 7 exhibited potent anti-neuroinflammatory and NGF-potentiating activity. PMID:26706168

  20. Ocean optics

    SciTech Connect

    Spinard, R.W.; Carder, K.L.; Perry, M.J.

    1994-12-31

    This volume is the twenty fifth in the series of Oxford Monographs in Geology and Geophysics. The propagation off light in the hydra-atmosphere systems is governed by the integral-differential Radiative Transfer Equation (RTE). Closure and inversion are the most common techniques in optical oceanography to understand the most basic principles of natural variability. Three types of closure are dealt with: scale closure, experimental closure, and instrument closure. The subject is well introduced by Spinard et al. in the Preface while Howard Gordon in Chapter 1 provides an in-depth introduction to the RTE and its inherent problems. Inherent and apparent optical properties are dealt with in Chapter 2 by John Kirk and the realities of optical closure are presented in the following chapter by Ronald Zaneveld. The balance of the papers in this volume is quite varied. The early papers deal in a very mathematical manner with the basics of radiative transfer and the relationship between inherent and optical properties. Polarization of sea water is discussed in a chapter that contains a chronological listing of discoveries in polarization, starting at about 1000 AD with the discovery of dichroic properties of crystals by the Vikings and ending with the demonstration of polarotaxis in certain marine organisms by Waterman in 1972. Chapter 12 on Raman scattering in pure water and the pattern recognition techniques presented in Chapter 13 on the optical effects of large particles may be of relevance to fields outside ocean optics.

  1. Potential risks of pharmacy compounding.

    PubMed

    Gudeman, Jennifer; Jozwiakowski, Michael; Chollet, John; Randell, Michael

    2013-03-01

    Pharmacy compounding involves the preparation of customized medications that are not commercially available for individual patients with specialized medical needs. Traditional pharmacy compounding is appropriate when done on a small scale by pharmacists who prepare the medication based on an individual prescription. However, the regulatory oversight of pharmacy compounding is significantly less rigorous than that required for Food and Drug Administration (FDA)-approved drugs; as such, compounded drugs may pose additional risks to patients. FDA-approved drugs are made and tested in accordance with good manufacturing practice regulations (GMPs), which are federal statutes that govern the production and testing of pharmaceutical products. In contrast, compounded drugs are exempt from GMPs, and testing to assess product quality is inconsistent. Unlike FDA-approved drugs, pharmacy-compounded products are not clinically evaluated for safety or efficacy. In addition, compounded preparations do not have standard product labeling or prescribing information with instructions for safe use. Compounding pharmacies are not required to report adverse events to the FDA, which is mandatory for manufacturers of FDA-regulated medications. Some pharmacies engage in activities that extend beyond the boundaries of traditional pharmacy compounding, such as large-scale production of compounded medications without individual patient prescriptions, compounding drugs that have not been approved for use in the US, and creating copies of FDA-approved drugs. Compounding drugs in the absence of GMPs increases the potential for preparation errors. When compounding is performed on a large scale, such errors may adversely affect many patients. Published reports of independent testing by the FDA, state agencies, and others consistently show that compounded drugs fail to meet specifications at a considerably higher rate than FDA-approved drugs. Compounded sterile preparations pose the additional risk

  2. Metal optics and superconductivity

    SciTech Connect

    Golovashkin, A.L.

    1989-01-01

    The articles contained in this collection are dedicated to the study of the electron structure of transition metals and superconducting alloys and compounds based on them. The study of the electron structure of materials is one of the central problems of solid-state physics and defines the solution of a number of problems. One of them is the problem of high-temperature superconductivity which has attracted exceptional attention from physicists in connection with the discovery of new classes of ceramic oxides which are superconducting at liquid-nitrogen temperature. The electron structure is one of the three whales on which all of superconductivity rests. It is frequently our ignorance of the electronic properties of a metal, alloy or compound in its normal state which makes it impossible to predict superconductivity in the material, preventing use from calculating the parameters of the superconducting state. There are now a number of effective methods for investigation of the electron structure of the metals and allows. This collection discusses metal optics, tunneling and magnetic measurements in superconductors. These methods are quite informative and allow us to obtain many important electron characteristics and temperature relations. Various characteristics of the superconducting compounds Nb{sub 3}Ge, Nb{sub 3}Al, nb{sub 3}Sn and Nb{sub 3}Ga with A15 structure and NbN with B1 structure, having rather high critical temperatures, are experimentally studied.

  3. Optical resolution of rotenoids

    USGS Publications Warehouse

    Abidi, S.L.

    1987-01-01

    Optical resolution of selected rotenoids containing 1-3 asymmetric centers in dihydrobenzopyranofuroben-zopyranone and dihydrobisbenzopyranopyranone series has been achieved on two chiral high-performance liquid chromatographic (hplc) stationary phases. In most cases, the absolute stereochemistry at the cis-B/C ring junction of the rotenoidal antipodes can be related to their elution order. Generally, the 6aα,12aα-enantiomers were more strongly retained by the chiral substrate than their corresponding optical antipodes. The elution-configuration relationship provides potential utility for predicting the absolute configuration of related rotenoidal compounds. Chiral phase hplc on amino-acid-bonded-silica yielded results explicable in terms of Pirkle's bonding schemes for chiral recognition. Resolution data for 12a-hydroxy-, 12a-methoxy-, and 12-hydroxyiminorotenoids further corroborate the mechanistic rationale, and demonstrate that nonpolar π-π interactions appeared to be important for enantiomeric separation on helic poly-triphenylmethylacryl-ate-silica (CPOT). In the latter system, steric effects and conformational factors in association with the modification of E-ring structures might play significant roles in the chiral separation process in view of the reversal to the elution order observed for all methoxylated rotenoids and elliptone derivatives including the parent deguelin. The unique separability (α = 1.44) of 12a-hydroxyelliptone on CPOT was suggestive of structural effects of the 5-side chain on the resolution of the rotenoids having a five-membered-E-ring. The results obtained with two different types of chiral phases are complementary and useful for optical resolution of a wide variety of natural and synthetic rotenoidal compounds.

  4. Optical biosensors for environmental monitoring

    SciTech Connect

    Tamiya, Eiichi

    1996-12-31

    Environmental assessment is important to evaluate the overall health and ecological impact of domestic and industrial wastes. Biosensors are kinds of analytical devices which consist of biomaterials and transducers. Photoluminescence of recombinant E. coli containing lux related genes were used as indicators of environmental pollutions. This paper deals with sensitive and rapid optical sensing systems for monitoring BOD (Biochemical Oxygen Demand), toxic compounds and mutagens.

  5. Turbo compound engine

    SciTech Connect

    Kawamura, H.

    1988-05-24

    A turbo compound engine having a first exhaust turbine coupled to an exhaust pipe of an internal combustion engine and a second exhaust turbine coupled to an exhaust port of the first exhaust turbine is described comprising: a first generator drivable by the first exhaust turbine; a second generator drivable by the second exhaust turbine; a motor operatively coupled to an output shaft of the internal combustion engine; speed detecting means for detecting the speed of rotation of the internal combustion engine; and control means for controlling the frequency of electric power, which is the sum of electric power outputs from the first and second generators and supplied to the motor, based on a signal from the speed detecting means, in order to control operation of the motor.

  6. Polydiacetylene thin films for nonlinear optical applications

    NASA Technical Reports Server (NTRS)

    Paley, Mark S.

    1993-01-01

    One very promising class of organic compounds for nonlinear optical (NLO) applications are polydiacetylenes, which are novel in that they are highly conjugated polymers which can also be crystalline. Polydiacetylenes offer several advantages over other organic materials: because of their highly conjugated electronic structures, they are capable of possessing large optical nonlinearities with fast response times; because they are crystalline, they can be highly ordered, which is essential for optimizing their NLO properties; and, last, because they are polymeric, they can be formed as thin films, which are useful for device fabrication. We have actively been carrying out ground-based research on several compounds of interest.

  7. Optical DNA

    NASA Astrophysics Data System (ADS)

    Vijaywargi, Deepak; Lewis, Dave; Kirovski, Darko

    A certificate of authenticity (COA) is an inexpensive physical object with a random and unique structure S which is hard to near-exactly replicate. An inexpensive device should be able to scan object’s physical “fingerprint,” a set of features that represents S. In this paper, we explore one set of requirements that optical media such as DVDs should satisfy, to be considered as COAs. As manufacturing of such media produces inevitable errors, we use the locations and count of these errors as a “fingerprint” for each optical disc: its optical DNA. The “fingerprint” is signed using publisher’s private-key and the resulting signature is stored onto the optical medium using a post-production process. Standard DVD players with altered firmware that includes publisher’s public-key, should be able to verify the authenticity of DVDs protected with optical DNA. Our key finding is that for the proposed protocol, only DVDs with exceptional wear-and-tear characteristics would result in an inexpensive and viable anti-counterfeiting technology.

  8. Application of optical design software in the analysis of "unknown" optical systems

    NASA Astrophysics Data System (ADS)

    Roudnicky, Dunja S.

    1998-08-01

    Optical design software is not very usable in designing new optical systems only, but also in analysis of `unknown' systems. When measurements of radii of curvature, focal lengths and axial thickness of elements are done, we use SIGMA 2100 Optical design software (Kidger Optics). We determine which optical glass fits the nearest measured focal length of each element. We also get aberration curves of elements and the whole system. In such a way we analyze elements of an eyepiece which is the part of a compound panoramic sight. Since we now have all specifications of this eyepiece, it is possible to optimize glasses and radii to the more convenient ones, without a risk to change the performance of the whole optical system. This method gives us a possibility of reparation and adaptation of `unknown' optical systems with a high yield.

  9. DEMONSTRATION BULLETIN: RAPID OPTICAL SCREEN TOOL (ROST™) - LORAL CORPORATION

    EPA Science Inventory

    The Loral Rapid Optical Screen Tool (ROST™) is a tunable dye laser system used for the detection of petroleum, semi-volatile, and some volatile organic compounds in soils. The technology is used in conjunction with a cone penetrometer (CP).

  10. Optical analyzer

    DOEpatents

    Hansen, A.D.

    1987-09-28

    An optical analyzer wherein a sample of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter is placed in a combustion tube, and light from a light source is passed through the sample. The temperature of the sample is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample is detected as the temperature is raised. A data processor, differentiator and a two pen recorder provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample. These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample. Additional information is obtained by repeating the run in different atmospheres and/or different rates or heating with other samples of the same particulate material collected on other filters. 7 figs.

  11. Optical coupler

    DOEpatents

    Majewski, Stanislaw; Weisenberger, Andrew G.

    2004-06-15

    In a camera or similar radiation sensitive device comprising a pixilated scintillation layer, a light guide and an array of position sensitive photomultiplier tubes, wherein there exists so-called dead space between adjacent photomultiplier tubes the improvement comprising a two part light guide comprising a first planar light spreading layer or portion having a first surface that addresses the scintillation layer and optically coupled thereto at a second surface that addresses the photomultiplier tubes, a second layer or portion comprising an array of trapezoidal light collectors defining gaps that span said dead space and are individually optically coupled to individual position sensitive photomultiplier tubes. According to a preferred embodiment, coupling of the trapezoidal light collectors to the position sensitive photomultiplier tubes is accomplished using an optical grease having about the same refractive index as the material of construction of the two part light guide.

  12. Optical memory

    DOEpatents

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  13. Statistical optics

    NASA Astrophysics Data System (ADS)

    Goodman, J. W.

    This book is based on the thesis that some training in the area of statistical optics should be included as a standard part of any advanced optics curriculum. Random variables are discussed, taking into account definitions of probability and random variables, distribution functions and density functions, an extension to two or more random variables, statistical averages, transformations of random variables, sums of real random variables, Gaussian random variables, complex-valued random variables, and random phasor sums. Other subjects examined are related to random processes, some first-order properties of light waves, the coherence of optical waves, some problems involving high-order coherence, effects of partial coherence on imaging systems, imaging in the presence of randomly inhomogeneous media, and fundamental limits in photoelectric detection of light. Attention is given to deterministic versus statistical phenomena and models, the Fourier transform, and the fourth-order moment of the spectrum of a detected speckle image.

  14. Optical resonator

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    The invention discloses a semi-ring Fabry-Perot (SRFP) optical resonator structure comprising a medium including an edge forming a reflective facet and a waveguide within the medium, the waveguide having opposing ends formed by the reflective facet. The performance of the SRFP resonator can be further enhanced by including a Mach-Zehnder interferometer in the waveguide on one side of the gain medium. The optical resonator can be employed in a variety of optical devices. Laser structures using at least one SRFP resonator are disclosed where the resonators are disposed on opposite sides of a gain medium. Other laser structures employing one or more resonators on one side of a gain region are also disclosed.

  15. Optical switch

    DOEpatents

    Reedy, Robert P.

    1987-01-01

    An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

  16. Novel ocular antihypertensive compounds in clinical trials

    PubMed Central

    Chen, June; Runyan, Stephen A; Robinson, Michael R

    2011-01-01

    Introduction: Glaucoma is a multifactorial disease characterized by progressive optic nerve injury and visual field defects. Elevated intraocular pressure (IOP) is the most widely recognized risk factor for the onset and progression of open-angle glaucoma, and IOP-lowering medications comprise the primary treatment strategy. IOP elevation in glaucoma is associated with diminished or obstructed aqueous humor outflow. Pharmacotherapy reduces IOP by suppressing aqueous inflow and/or increasing aqueous outflow. Purpose: This review focuses on novel non-FDA approved ocular antihypertensive compounds being investigated for IOP reduction in ocular hypertensive and glaucoma patients in active clinical trials within approximately the past 2 years. Methods: The mode of IOP reduction, pharmacology, efficacy, and safety of these new agents were assessed. Relevant drug efficacy and safety trials were identified from searches of various scientific literature databases and clinical trial registries. Compounds with no specified drug class, insufficient background information, reformulations, and fixed-combinations of marketed drugs were not considered. Results: The investigational agents identified comprise those that act on the same targets of established drug classes approved by the FDA (ie, prostaglandin analogs and β-adrenergic blockers) as well as agents belonging to novel drug classes with unique mechanisms of action. Novel targets and compounds evaluated in clinical trials include an actin polymerization inhibitor (ie, latrunculin), Rho-associated protein kinase inhibitors, adenosine receptor analogs, an angiotensin II type 1 receptor antagonist, cannabinoid receptor agonists, and a serotonin receptor antagonist. Conclusion: The clinical value of novel compounds for the treatment of glaucoma will depend ultimately on demonstrating favorable efficacy and benefit-to-risk ratios relative to currently approved prostaglandin analogs and β-blockers and/or having complementary

  17. Group-IV semiconductor compounds

    SciTech Connect

    Berding, M.A.; Sher, A.; van Schilfgaarde, M.

    1997-08-01

    Properties of ordered group-IV compounds containing carbon, silicon, and germanium are calculated within the local density approximation. Twenty-seven fully relaxed compounds represented by seven different compound structures are compared and, with the exception of SiC, all compounds are found to be metastable. Two trends emerge: carbon-germanium bonds are disfavored, and compounds that have carbon on a common sublattice are the least unbound because of their relatively low strain. When carbon shares a sublattice with silicon or germanium, the large strain results in a narrowing of the band gap, and in some cases the compound is metallic. The most promising structures with the lowest excess energy contain carbon on one sublattice and although they do not lattice match to silicon, they match rather well to silicon carbide. {copyright} {ital 1997} {ital The American Physical Society}

  18. Compound chondrules: an experimental investigation

    NASA Astrophysics Data System (ADS)

    Connolly, H. C., Jr.; Hewins, R. H.; Atre, N.; Lofgren, G. E.

    1994-07-01

    Compound chondrules are considered to be the product of collisions between molten chondrules during chondrule formation Wasson, J. T. et al. (1994) have argued that some compound chondrules are formed when a chondrule with an accretional rim experienced a flash-melting event similar to a chondrule-forming event. We have designed experiments to investigate the formation of compound chondrules by both methods. Experiments were performed on a Deltech vertical muffle tube furnace to form synthetic chondrules to use as accretion rim material. For our experimental conditions, it is clear that compound chondrules can only be made by a collisional event. Our changes maintain their spherical shape and produce distinct boundaries between charges that are similar to natural compound chondrules. Furthermore, collision event(s) between chondrules will cause nucleation if they are molten and undercooled, thus producing chondrule textures. Flash melting chondrules with accretionary rims will not produce compound chondrules but will produce new chondrules with new textures.

  19. Compounding with Silicones.

    PubMed

    Allen, Loyd V

    2015-01-01

    Since the 1940s, methylchlorosilanes have been used to treat glassware to prevent blood from clotting. The use of silicones in pharmaceutical and medical applications has grown to where today they are used in many life-saving devices (pacemakers, hydrocephalic shunts) and pharmaceutical applications from tubing, to excipients in topical formulations, to adhesives to affix transdermal drug delivery systems, and are also being used in products as active pharmaceutical ingredients, such as antiflatulents. About 60% of today's skin-care products now contain some type of silicone where they are considered safe and are known to provide a pleasant "silky-touch," non-greasy, and non-staining feel. Silicones exhibit many useful characteristics, and the safety of these agents supports their numerous applications; their biocompatibility is partially due to their low-chemical reactivity displayed by silicones, low-surface energy, and their hydrophobicity. Silicones are used both as active ingredients and as excipients. In addition is their use for "siliconization," or surface treatment, of many parenteral packaging components. Dimethicone and silicone oil are used as lubricants on stoppers to aid machineability, in syringes to aid piston movement, or on syringe needles to reduce pain upon injection. Silicones are also useful in pharmaceutical compounding as is discussed in this artiele included with this article are in developing formulations with silicones. PMID:26714363

  20. Compounding in synthetic aperture imaging.

    PubMed

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-09-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution and clutter levels are measured using a wire phantom setup and compared with conventional application of the array, as well as to synthetic aperture imaging without compounding. If the full aperture is used for synthetic aperture compounding, the cystic resolution is improved by 41% compared with conventional imaging, and is at least as good as what can be obtained using synthetic aperture imaging without compounding. PMID:23007781

  1. New England Compounding Center Indictment.

    PubMed

    Cabaleiro, Joe

    2015-01-01

    This article is a review of the lapses in compliance with United States Pharmacopeia standards and pharmacy law as alleged by the New England Compounding Center indictment. This indictment was a result of an outbreak of fungal meningitis traced to fungal contamination of compounded methylprednisolone suspension for epidural steroid injections. This article is also intended as a gap analysis for compounders to review compliance at their own facility, and, if necessary, take the appropriate steps to implement best practices. PMID:26685489

  2. Method of producing cyclohexasilane compounds

    SciTech Connect

    Elangovan, Arumugasamy; Anderson, Kenneth; Boudjouk, Philip R; Schulz, Douglas L

    2015-03-10

    A method of preparing a cyclohexasilane compound from trichlorosilane is provided. The method includes contacting trichlorosilane with a reagent composition to produce a compound containing a tetradecahalocyclohexasilane dianion, such as a tetradecachlorocyclohexasilane dianion. The reagent composition typically includes (a) tertiary polyamine ligand; and (b) a deprotonating reagent, such as a tertiary amine having a pKa of at least about 10.5. Methods of converting the tetradecahalocyclohexasilane dianion-containing compound to cyclohexasilane or a dodecaorganocyclohexasilane are also provided.

  3. Method of preparing metallocene compounds

    DOEpatents

    Rosenblum, Myron; Matchett, Stephen A.

    1992-01-01

    This invention describes a novel method of preparing metallocene compounds. The invention is based on synthesis of novel bis cyclopentadienides that, under appropriate conditions, will either encapsulate a transition metal to produce a metallocene such as ferrocene, or ferrocene derivative, or will yield a polymeric metallocene. Compounds produced by this process are useful as catalysts in propulsion systems, or as anti-knock compounds in gasolines.

  4. Optical pantograph

    NASA Technical Reports Server (NTRS)

    Belew, Robert R. (Inventor); Davis, Donald E. (Inventor)

    1976-01-01

    An optical pantograph for directing light beams and the like from a source to a receiver according to the movement of a pointer. The device can be used for, among other things, directing a laser beam and the like to a target for etching patterns on a target according to the movement of a pointer relative to a pattern trace.

  5. Optical electronics

    NASA Technical Reports Server (NTRS)

    Javan, A.

    1976-01-01

    The development of an optical diode consisting of a metal-dielectric-metal junction in which the high-speed electric conduction process occurs due to quantum mechanical electron tunneling across the dielectric barrier is briefly reviewed. Potential applications of the diode are discussed.

  6. Optical Storage.

    ERIC Educational Resources Information Center

    Vanderstar, John

    1987-01-01

    Classifies and briefly describes several types of optical storage media available today--read-only and write-once analog disks, read-only and write-once digital disks and erasable disks. The appropriateness of CD-ROM (compact disk read-only memory) for use in libraries of developing nations is discussed in terms of users' information needs and…

  7. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-03-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking.

  8. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-02-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking.

  9. Optical Fibers

    NASA Astrophysics Data System (ADS)

    Ghatak, Ajoy; Thyagarajan, K.

    With the development of extremely low-loss optical fibers and their application to communication systems, a revolution has taken fiber glass place during the last 40 years. In 2001, using glass fibers as the transmission medium and lightwaves as carrier wave waves, information was transmitted at a rate more than 1 Tbit/s (which is roughly equivalent to transmission of about 15 million simultaneous telephone conversations) through one hair thin optical fiber. Experimental demonstration of transmission at the rate of 14 Tbit/s over a 160 km long single fiber was demonstrated in 2006, which is equivalent to sending 140 digital high definition movies in 1 s. Very recently record transmission of more than 100 Tbit/s over 165 km single mode fiber has been reported. These can be considered as extremely important technological achievements. In this chapter we will discuss the propagation characteristics of optical fibers with special applications to optical communication systems and also present some of the noncommunication applications such as sensing.

  10. Diophantine Optics

    NASA Astrophysics Data System (ADS)

    Rouan, D.

    2016-09-01

    What I call Diophantine optics is the exploitation in optics of some remarkable algebraic relations between powers of integers. The name comes from Diophantus of Alexandria, a greek mathematician, known as the father of algebra. He studied polynomial equations with integer coefficients and integer solutions, called diophantine equations. Since constructive or destructive interferences are playing with optical path differences which are multiple integer (odd or even) of λ/2 and that the complex amplitude is a highly non-linear function of the optical path difference (or equivalently of the phase), one can understand that any Taylor development of this amplitude implies powers of integers. This is the link with Diophantine equations. We show how, especially in the field of interferometry, remarkable relations between powers of integers can help to solve several problems, such as achromatization of a phase shifter or deep nulling efficiency. It appears that all the research that was conducted in this frame of thinking, relates to the field of detection of exoplanets, a very active domain of astrophysics today.

  11. Skin optics

    SciTech Connect

    van Gemert, M.J.; Jacques, S.L.; Sterenborg, H.J.; Star, W.M.

    1989-12-01

    Quantitative dosimetry in the treatment of skin disorders with (laser) light requires information on propagation of light in the skin related to the optical properties of the individual skin layers. This involves the solution of the integro-differential equation of radiative transfer in a model representing skin geometry, as well as experimental methods to determine the optical properties of each skin layer. These activities are unified under the name skin optics. This paper first reviews the current status of tissue optics, distinguishing between the cases of: dominant absorption, dominant scattering, and scattering about equal to absorption. Then, previously published data as well as some current unpublished data on (human) stratum corneum, epidermis and dermis, have been collected and/or (re)analyzed in terms of absorption coefficient, scattering coefficient, and anisotropy factor of scattering. The results are that the individual skin layers show strongly forward scattering (anisotropy factors between 0.7 and 0.9). The absorption and scattering data show that for all wavelengths considered scattering is much more important than absorption. Under such circumstances, solutions to the transport equation for a multilayer skin model and finite beam laser irradiation are currently not yet available. Hence, any quantitative dosimetry for skin treated with (laser) light is currently lacking.

  12. Multi-point sources and imaging compound infrared target simulator

    NASA Astrophysics Data System (ADS)

    Shi, Rui; Xu, Rui; Wang, Hongjie; Wang, Xin; Wu, Di; Li, Zhuo

    2014-11-01

    Infrared target simulator is an important unit in guidance hardware-in-the-loop simulation systems. It is used to simulate the radiation and motion characteristics of target, decoy and background. This paper proposed a multi-channel IR target simulator. It could generate one IR point target, two pairs of IR decoys and background respectively in the same field of view of the seeker's optical system simultaneously. An IR imaging fiber bundle as the focal plane of the projection optical system was used to compound the target, decoys and background. The compound scene was projected to the seeker by the projection optical system. In IR imaging channel, IR scene was generated by an optical film chip as a visible to thermal transducer which was placed in a vacuum cell. The simulated temperature range of IR scene could be from room temperature to 430K.The thin film transducer had 512×512 pixels. Its frame rate could reach to 100Hz. Light sources with high equivalent black body temperature were adopted in IR target and decoy channels. The size and the radiation intensity of the IR point target and decoys could be controlled by pin holes and attenuators. The point target and decoys driven by high precise motors could travel through the whole instantaneous field of view of the seeker's optical system. Two pairs of decoys could move away from the center to the edge of the instantaneous field of view. The highest simulated black body temperature of the point source was 1200K.

  13. Biomedical Compounds from Marine organisms

    PubMed Central

    Jha, Rajeev Kumar; Zi-rong, Xu

    2004-01-01

    The Ocean, which is called the ‘mother of origin of life’, is also the source of structurally unique natural products that are mainly accumulated in living organisms. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immuno-deficiency syndrome (AIDS), arthritis, etc., while other compounds have been developed as analgesics or to treat inflammation, etc. The life-saving drugs are mainly found abundantly in microorganisms, algae and invertebrates, while they are scarce in vertebrates. Modern technologies have opened vast areas of research for the extraction of biomedical compounds from oceans and seas.

  14. Organic Compounds in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  15. Optical superheterodyne receiver.

    NASA Technical Reports Server (NTRS)

    Duval, K.; Lang, K.; Lucy, R. F.; Peters, C. J.

    1967-01-01

    Optical communication experiments to compare coherent and noncoherent optical detection fading characteristics in different weather conditions, using laser transmitter and optical superheterodyne receiver

  16. Optical Magnetometry

    NASA Astrophysics Data System (ADS)

    Budker, Dmitry; Kimball, Derek F. Jackson

    2013-03-01

    Part I. Principles and Techniques: 1. General principles and characteristics of optical magnetometers D. F. Jackson Kimball, E. B. Alexandrov and D. Budker; 2. Quantum noise in atomic magnetometers M. V. Romalis; 3. Quantum noise, squeezing, and entanglement in radio-frequency optical magnetometers K. Jensen and E. S. Polzik; 4. Mx and Mz magnetometers E. B. Alexandrov and A. K. Vershovskiy; 5. Spin-exchange-relaxation-free (serf) magnetometers I. Savukov and S. J. Seltzer; 6. Optical magnetometry with modulated light D. F. Jackson Kimball, S. Pustelny, V. V. Yashchuk and D. Budker; 7. Microfabricated atomic magnetometers S. Knappe and J. Kitching; 8. Optical magnetometry with nitrogen-vacancy centers in diamond V. M. Acosta, D. Budker, P. R. Hemmer, J. R. Maze and R. L. Walsworth; 9. Magnetometry with cold atoms W. Gawlik and J. M. Higbie; 10. Helium magnetometers R. E. Slocum, D. D. McGregor and A. W. Brown; 11. Surface coatings for atomic magnetometry S. J. Seltzer, M.-A. Bouchiat and M. V. Balabas; 12. Magnetic shielding V. V. Yashchuk, S.-K. Lee and E. Paperno; Part II. Applications: 13. Remote detection magnetometry S. M. Rochester, J. M. Higbie, B. Patton, D. Budker, R. Holzlöhner and D. Bonaccini Calia; 14. Detection of nuclear magnetic resonance with atomic magnetometers M. P. Ledbetter, I. Savukov, S. J. Seltzer and D. Budker; 15. Space magnetometry B. Patton, A. W. Brown, R. E. Slocum and E. J. Smith; 16. Detection of biomagnetic fields A. Ben-Amar Baranga, T. G. Walker and R. T. Wakai; 17. Geophysical applications M. D. Prouty, R. Johnson, I. Hrvoic and A. K. Vershovskiy; Part III. Broader Impact: 18. Tests of fundamental physics with optical magnetometers D. F. Jackson Kimball, S. K. Lamoreaux and T. E. Chupp; 19. Nuclear magnetic resonance gyroscopes E. A. Donley and J. Kitching; 20. Commercial magnetometers and their application D. C. Hovde, M. D. Prouty, I. Hrvoic and R. E. Slocum; Index.

  17. Lattice dynamics study of bismuth III V compounds

    NASA Astrophysics Data System (ADS)

    Belabbes, A.; Zaoui, A.; Ferhat, M.

    2008-10-01

    We present first-principles calculations of the structural and lattice-dynamical properties for cubic bismuth III-V compounds: BBi, AlBi and GaBi. The ground-state properties, i.e., the lattice constant and the bulk modulus, are calculated using a plane wave pseudopotential method within density functional theory. A linear-response approach to density functional theory is used to derive the phonon frequencies. The effect of pressure on the dynamical charges and the longitudinal optical-transverse optical splitting is also examined.

  18. Optical Study of Interactions in a d-Electron Kondo Lattice with Ferromagnetism

    SciTech Connect

    Burch, K. S.; Schafgans, A.; Butch, N. P.; Sayles, T. A.; Maple, M. B.; Sales, Brian C; Mandrus, David; Basov, D. N.

    2005-01-01

    We report on a comprehensive optical, transport, and thermodynamic study of the Zintl compound Yb{sub 14}MnSb{sub 11}, demonstrating that it is the first ferromagnetic Kondo lattice compound in the underscreened limit. We propose a scenario whereby the combination of Kondo and Jahn-Teller effects provides a consistent explanation of both transport and optical data.

  19. Antimicrobial Compounds in Tears

    PubMed Central

    McDermott, Alison M.

    2013-01-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. PMID:23880529

  20. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-09-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. Scope of Submission The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities To submit to this special issue, follow the normal procedure for submission to JON, indicating "Optical Ethernet feature" in the "Comments" field of the online submission form. For all other questions

  1. Computational assessment of organic photovoltaic candidate compounds

    NASA Astrophysics Data System (ADS)

    Borunda, Mario; Dai, Shuo; Olivares-Amaya, Roberto; Amador-Bedolla, Carlos; Aspuru-Guzik, Alan

    2015-03-01

    Organic photovoltaic (OPV) cells are emerging as a possible renewable alternative to petroleum based resources and are needed to meet our growing demand for energy. Although not as efficient as silicon based cells, OPV cells have as an advantage that their manufacturing cost is potentially lower. The Harvard Clean Energy Project, using a cheminformatic approach of pattern recognition and machine learning strategies, has ranked a molecular library of more than 2.6 million candidate compounds based on their performance as possible OPV materials. Here, we present a ranking of the top 1000 molecules for use as photovoltaic materials based on their optical absorption properties obtained via time-dependent density functional theory. This computational search has revealed the molecular motifs shared by the set of most promising molecules.

  2. Antifungal Compounds from Piper Species

    PubMed Central

    Xu, Wen-Hui; Li, Xing-Cong

    2013-01-01

    This review documents chemical structures and antifungal activities of 68 compounds isolated from 22 Piper species of the plant family Piperaceae. These compounds include amides, flavonoids, prenylated benzoic acid derivatives, lignans, phenylpropanoids, butenolides, and cyclopentendiones. Some of them may serve as leads for potential pharmaceutical or agricultural fungicide development. PMID:24307889

  3. Morphological Dynamics in Compound Processing

    ERIC Educational Resources Information Center

    Kuperman, Victor; Bertram, Raymond; Baayen, R. Harald

    2008-01-01

    This paper explores the time-course of morphological processing of trimorphemic Finnish compounds. We find evidence for the parallel access to full-forms and morphological constituents diagnosed by the early effects of compound frequency, as well as early effects of left constituent frequency and family size. We also observe an interaction between…

  4. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English…

  5. ATMOSPHERIC FREONS AND HALOGENATED COMPOUNDS

    EPA Science Inventory

    Ambient levels of atmospheric Freons, halogenated hydrocarbons, and SF6 were measured at various locations in the U.S.A. Compounds such as CCl3F, CCl2F2, CH3-CCl3, and CCl4 were ubiquitious and generally measured at sub ppb levels. Tropospherically reactive compounds such as C2Cl...

  6. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  7. Soft optics in intelligent optical networks

    NASA Astrophysics Data System (ADS)

    Shue, Chikong; Cao, Yang

    2001-10-01

    In addition to the recent advances in Hard-optics that pushes the optical transmission speed, distance, wave density and optical switching capacity, Soft-optics provides the necessary intelligence and control software that reduces operational costs, increase efficiency, and enhances revenue generating services by automating optimal optical circuit placement and restoration, and enabling value-added new services like Optical VPN. This paper describes the advances in 1) Overall Hard-optics and Soft-optics 2) Layered hierarchy of Soft-optics 3) Component of Soft-optics, including hard-optics drivers, Management Soft-optics, Routing Soft-optics and System Soft-optics 4) Key component of Routing and System Soft-optics, namely optical routing and signaling (including UNI/NNI and GMPLS signaling). In summary, the soft-optics on a new generation of OXC's enables Intelligent Optical Networks to provide just-in-time service delivery and fast restoration, and real-time capacity management that eliminates stranded bandwidth. It reduces operational costs and provides new revenue opportunities.

  8. Nano-Scale Fabrication Using Optical-Near-Field

    NASA Astrophysics Data System (ADS)

    Yatsui, Takashi; Ohtsu, Motoichi

    This paper reviews the specific nature of nanophotonics, i.e., a novel optical nano-technology, utilizing dressed photon excited in the nano-material. As examples of nanophotnic fabrication, optical near-field etching and increased spatial homogeneity of contents in compound semiconductors is demonstrated with a self-organized manner.

  9. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, S.D.; Marshall, K.L.; Cerqua, K.A.

    1991-10-08

    Composite optical devices are disclosed using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T[sub g]) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device. 7 figures.

  10. Methods of making composite optical devices employing polymer liquid crystal

    DOEpatents

    Jacobs, Stephen D.; Marshall, Kenneth L.; Cerqua, Kathleen A.

    1991-01-01

    Composite optical devices using polymer liquid crystal materials both as optical and adhesive elements. The devices are made by assembling a heated polymer liquid crystal compound, while in a low viscosity form between optically transparent substrates. The molecules of the polymer are oriented, while in the liquid crystalline state and while above the glass transition temperature (T.sub.g) of the polymer, to provide the desired optical effects, such as polarization, and selective reflection. The liquid crystal polymer cements the substrates together to form an assembly providing the composite optical device.

  11. Optic nerve atrophy

    MedlinePlus

    Optic atrophy; Optic neuropathy ... There are many causes of optic atrophy. The most common is poor blood flow. This is called ischemic optic neuropathy. The problem most often affects older adults. ...

  12. Ocean optics IX

    SciTech Connect

    Blizard, M.A.

    1988-01-01

    These proceedings collect papers on optics and optical properties. Topics include: optical properties of water laser bathymetry, scattering from marine organisms, optically stimulated sound from bubbles, underwater laser-based imaging systems, and remote sensing of ocean physical properties.

  13. Optic nerve atrophy

    MedlinePlus

    Optic nerve atrophy is damage to the optic nerve. The optic nerve carries images of what the eye sees to ... problem most often affects older adults. The optic nerve can also be damaged by shock, toxins, radiation, ...

  14. Bilayer Effects of Antimalarial Compounds.

    PubMed

    Ramsey, Nicole B; Andersen, Olaf S

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  15. Macrocyclic compounds as corrosion inhibitors

    SciTech Connect

    Quraishi, M.A.; Rawat, J.; Ajmal, M.

    1998-12-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I{sup {minus}}) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkin`s adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulfur atoms.

  16. Assimilation of Unusual Carbon Compounds

    NASA Astrophysics Data System (ADS)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  17. Antiparasitic Compounds That Target DNA

    PubMed Central

    Wilson, W. David; Tanious, Farial A.; Mathis, Amanda; Tevis, Denise; Hall, James Edwin; Boykin, David W.

    2008-01-01

    Designed, synthetic heterocyclic diamidines have excellent activity against eukaryotic parasites that cause diseases such as sleeping sickness and leishmania and adversely affect millions of people each year. The most active compounds bind specifically and strongly in the DNA minor groove at AT sequences. The compounds enter parasite cells rapidly and appear first in the kinetoplast that contains the mitochondrial DNA of the parasite. With time the compounds are also generally seen in the cell nucleus but are not significantly observed in the cytoplasm. The kinetoplast decays over time and disappears from the mitochondria of treated cells. At this point the compounds begin to be observed in other regions of the cell, such as the acidocalcisomes. The cells typically die in 24–48 hours after treatment. Active compounds appear to selectively target extended AT sequences and induce changes in kinetoplast DNA minicircles that cause a synergistic destruction of the catenated kinetoplast DNA network and cell death. PMID:18343228

  18. Bilayer Effects of Antimalarial Compounds

    PubMed Central

    Ramsey, Nicole B.; Andersen, Olaf S.

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  19. Devices for collecting chemical compounds

    DOEpatents

    Scott, Jill R; Groenewold, Gary S

    2013-12-24

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  20. Optical aeronomy

    SciTech Connect

    Solomon, S.C. )

    1991-01-01

    Optical measurements of thermospheric and ionospheric processes and their interpretation are reviewed and the chemical reactions and their effects on emissions are discussed. Also included are the phenomena which excite the airglow and aurora, i.e., the solar UV/EUV flux and auroral particle precipitation. Consideration is given to solar flux, atomic emissions, molecular emissions, hydrogen geocorona, and molecular oxygen and the green line nightglow.

  1. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-04-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities

  2. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-07-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities

  3. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-06-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities

  4. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-08-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities

  5. Optical Ethernet

    NASA Astrophysics Data System (ADS)

    Chan, Calvin C. K.; Lam, Cedric F.; Tsang, Danny H. K.

    2005-05-01

    Call for Papers: Optical Ethernet The Journal of Optical Networking (JON) is soliciting papers for a second feature issue on Optical Ethernet. Ethernet has evolved from a LAN technology connecting desktop computers to a universal broadband network interface. It is not only the vehicle for local data connectivity but also the standard interface for next-generation network equipment such as video servers and IP telephony. High-speed Ethernet has been increasingly assuming the volume of backbone network traffic from SONET/SDH-based circuit applications. It is clear that IP has become the universal network protocol for future converged networks, and Ethernet is becoming the ubiquitous link layer for connectivity. Network operators have been offering Ethernet services for several years. Problems and new requirements in Ethernet service offerings have been captured through previous experience. New study groups and standards bodies have been formed to address these problems. This feature issue aims at reviewing and updating the new developments and R&D efforts of high-speed Ethernet in recent years, especially those related to the field of optical networking. The scope of the papers includes, but is not limited to, the following: Ethernet PHY development 10-Gbit Ethernet on multimode fiber Native Ethernet transport and Ethernet on legacy networks EPON Ethernet OAM Resilient packet ring (RPR) and Ethernet QoS definition and management on Ethernet Ethernet protection switching Circuit emulation services on Ethernet Transparent LAN service development Carrier VLAN and Ethernet Ethernet MAC frame expansion Ethernet switching High-speed Ethernet applications Economic models of high-speed Ethernet services Ethernet field deployment and standard activities

  6. An Overhead Projection Demonstration of Optical Activity

    ERIC Educational Resources Information Center

    Hill, John W.

    1973-01-01

    Describes the use of two polarizing lenses, a yellow filter, an oatmeal bos, a piece of cardboard, a 1,000 ml beaker, and an overhead projector to demonstrate compound optical activity to large classes. Indicates the presence of an accuracy within 1-2 degrees of usually acceptable data. (CC)

  7. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-02-07

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  8. Optical analyzer

    DOEpatents

    Hansen, Anthony D.

    1989-01-01

    An optical analyzer (10) wherein a sample (19) of particulate matter, and particularly of organic matter, which has been collected on a quartz fiber filter (20) is placed in a combustion tube (11), and light from a light source (14) is passed through the sample (19). The temperature of the sample (19) is raised at a controlled rate and in a controlled atmosphere. The magnitude of the transmission of light through the sample (19) is detected (18) as the temperature is raised. A data processor (23), differentiator (28) and a two pen recorder (24) provide a chart of the optical transmission versus temperature and the rate of change of optical transmission versus temperature signatures (T and D) of the sample (19). These signatures provide information as to physical and chemical processes and a variety of quantitative and qualitative information about the sample (19). Additional information is obtained by repeating the run in different atmospheres and/or different rates of heating with other samples of the same particulate material collected on other filters.

  9. Foveated optics

    NASA Astrophysics Data System (ADS)

    Bryant, Kyle R.

    2016-05-01

    Foveated imaging can deliver two different resolutions on a single focal plane, which might inexpensively allow more capability for military systems. The following design study results provide starting examples, lessons learned, and helpful setup equations and pointers to aid the lens designer in any foveated lens design effort. Our goal is to put robust sensor in a small package with no moving parts, but still be able to perform some of the functions of a sensor in a moving gimbal. All of the elegant solutions are out (for various reasons). This study is an attempt to see if lens designs can solve this problem and realize some gains in performance versus cost for airborne sensors. We determined a series of design concepts to simultaneously deliver wide field of view and high foveal resolution without scanning or gimbals. Separate sensors for each field of view are easy and relatively inexpensive, but lead to bulky detectors and electronics. Folding and beam-combining of separate optical channels reduces sensor footprint, but induces image inversions and reduced transmission. Entirely common optics provide good resolution, but cannot provide a significant magnification increase in the foveal region. Offsetting the foveal region from the wide field center may not be physically realizable, but may be required for some applications. The design study revealed good general guidance for foveated optics designs with a cold stop. Key lessons learned involve managing distortion, telecentric imagers, matching image inversions and numerical apertures between channels, reimaging lenses, and creating clean resolution zone splits near internal focal planes.

  10. Fiber optic monitoring device

    DOEpatents

    Samborsky, James K.

    1993-01-01

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  11. Microscopic physical and chemical properties of graphite intercalation compounds

    SciTech Connect

    Eklund, P.C.

    1992-08-24

    Optical spectroscopy (Raman, FTIR and Reflection ) was used to study a variety of acceptor- and donor-type compounds synthesized to determine the microscopic models consistent with the spectrocsopic results. General finding is that the electrical conduction properties of these compounds can be understood on the basis that the intercalation of atomic and/or molecular species between the host graphite layers either raises or lowers the Fermi level (E{sub F)} in a graphitic band structure. This movement of E{sub F} is accomplished via a charge transfer of electrons from the intercalate layers to the graphitic layers (donor compounds), or vice versa (acceptor compounds). Furthermore, the band structure must be modified to take into account the layers of charge that occur as a result of the charge transfer. This charge layering introduces additional bands of states near E{sub F}, which are discussed. Charge-transfer also induces a perturbation of the graphitic normal mode frequencies which can be understood as the result of a contraction (acceptor compounds) or expansion (donor compounds) of the intralayer C-C bonds. Ab-initio calculations support this view and are in reasonable agreement with experimental data.

  12. Effect of Central Metal on Nonlinear Optical Properties of Porphyrins and Their Graphene Composites

    NASA Astrophysics Data System (ADS)

    Leng, Jian-Cai; Zhao, Li-Yun; Zhang, Yu-Jin; Ma, Hong

    2016-09-01

    The nonlinear optical properties of a series of newly synthesized porphyrins with different central metals and their covalently linked graphene composites are theoretically studied by numerically solving the rate equations and field intensity equation. Calculated results show that all the studied compounds are promising candidates for optical limiters, and graphene-porphyrin composites are expected to be preferable optical limiters because of their excellent nonlinear absorption abilities. In addition, the central metal in the porphyrin is found to be crucial to the optical power limiting and two-photon absorption performances of the compounds. Our results reproduce the experimental measurements. Additionally, special emphasis is placed on the factors that can affect the nonlinear optical properties of the compounds, indicating that one can create favorable nonlinear optical properties of the compounds by changing either the parameters of the absorber, including the concentration and thickness, or the pulse duration.

  13. Power optics

    NASA Astrophysics Data System (ADS)

    Apollonov, V. V.

    2014-02-01

    By using the theory we developed in the early 1970s, a broad range of phenomena is considered for an optical surface of a solid body that is exposed to radiation arbitrarily varying in time and producing temperature fields, thermoelastic stresses and thermal deformations on the surface layer. The examination is based on the relations (which are similar to Duhamel's integral formula from the theory of heat conduction) between the quantities characterising the thermal stress state in any nonstationary regimes of energy input into a solid. A peculiar feature of the analysis of the thermal stress state in this case consists in the fact that this relation comprises time as a parameter, which in turn is a consequence of incoherence of the quasi-stationary problem of thermoelasticity. This phenomenon is particularly important for the optics of high-power, high-pulse repetition rate lasers, which are being actively developed. In the review, we have recently published in Laser Physics, the thermal stress state of a solid is analysed. In this state, time is treated as an independent variable used in differentiation. Such an approach greatly reduces the applicability of the method. The review published contains data on the use of capillary porous structures made of various materials with different degrees of the surface development. Moreover, such structures can be efficiently employed to increase the heat exchange at a temperature below the boiling point of the coolant. In the present review we discuss the dependences of the limiting laser intensities on the duration of a pulse or a pulse train, corresponding to the three stages of the state of the reflecting surface and leading to unacceptable elastic deformations of the surface, to the plastic yield of the material accompanied by the formation of residual stresses and to the melting of the surface layer. We also analyse the problem of heat exchange in the surface layer with a liquid metal coolant pumped through it. The

  14. Power optics

    SciTech Connect

    Apollonov, V V

    2014-02-28

    By using the theory we developed in the early 1970s, a broad range of phenomena is considered for an optical surface of a solid body that is exposed to radiation arbitrarily varying in time and producing temperature fields, thermoelastic stresses and thermal deformations on the surface layer. The examination is based on the relations (which are similar to Duhamel's integral formula from the theory of heat conduction) between the quantities characterising the thermal stress state in any nonstationary regimes of energy input into a solid. A peculiar feature of the analysis of the thermal stress state in this case consists in the fact that this relation comprises time as a parameter, which in turn is a consequence of incoherence of the quasi-stationary problem of thermoelasticity. This phenomenon is particularly important for the optics of high-power, high-pulse repetition rate lasers, which are being actively developed. In the review, we have recently published in Laser Physics, the thermal stress state of a solid is analysed. In this state, time is treated as an independent variable used in differentiation. Such an approach greatly reduces the applicability of the method. The review published contains data on the use of capillary porous structures made of various materials with different degrees of the surface development. Moreover, such structures can be efficiently employed to increase the heat exchange at a temperature below the boiling point of the coolant. In the present review we discuss the dependences of the limiting laser intensities on the duration of a pulse or a pulse train, corresponding to the three stages of the state of the reflecting surface and leading to unacceptable elastic deformations of the surface, to the plastic yield of the material accompanied by the formation of residual stresses and to the melting of the surface layer. We also analyse the problem of heat exchange in the surface layer with a liquid metal coolant pumped through it. The

  15. Bisoxalamide Clarifiers to Improve Optical Performance of Polyethylene Resins

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Hill, Martin; Santos, Nestor, Jr.; Banks, Andrew; Huang, Jessica; Keene, Ellen; Keaton, Rich

    The use of special nucleating agents, often referred to as clarifying agents, to improve optical performance of polyethylene is not widely used in the industry. A series of bisoxalamide compounds were synthesized and mixed with linear low density polyethylene (LLDPE) to test clarification effects. In this talk, we will discuss structure/property relationship of these molecules on optical and thermal properties of LLDPE. Bisoxalamide clarifiers to improve optical performance of polyethylene resins.

  16. Magnetism in Bulk Vanadium Dioxide Compounds

    NASA Astrophysics Data System (ADS)

    Mengyan, P. W.; Lichti, R. L.; Baker, B. B.; Jayarathna, G.

    2015-03-01

    Vanadium dioxide (VO2) compounds show a metal-semiconductor transition (MST) near room temperature (stoichiometric VO2 is metallic T >TMST ~ 340 K and semiconducting T optical, electrical or barometric means. This ultrafast (sub ms) transition has been studied extensively and there is still considerable disagreement regarding the mechanism responsible for these transitions. Incorporation of a few atomic percent of H in VO2 stabilizes the metallic phase down to 200 K. Impurities such as W, Ti, Au, Cr or F lower or raise TMST without significantly modifying other properties. Some effects that dopants have on the material are well known, however, the role dopants play in modifying them is far from understood. This contribution presents results of the first muon spin rotation and relaxation (MuSR) measurements on bulk VO2 compounds where we find and characterize a low temperature magnetic phase that has not yet been reported. The introduction of 2.4 at% of W or 5 at% of Ti raise the onset of the magnetic phase from 35 K to nearly 170 K. MuSR probes the local magnetic environment and hence provides a direct measure of the local field properties.

  17. Irigenin - an isoflavone: a brief study on structural and optical properties

    NASA Astrophysics Data System (ADS)

    Buch, Soubiya M.; Mir, Feroz A.; Rehman, Shakeel ul; Qurishi, Mushtaq A.; Banday, Javid A.

    2013-06-01

    Irigenin, an isoflavone (mol. formula = C18H16O8), was isolated from the plant Iris hookeriana using dichloromethane as solvent. The compound was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible spectroscopy measurements. Structural analysis of XRD data confirmed the orthorhombic structure for the compound. The microstructure of the compound is an aggregate of microcrystals with an irregular morphology. From the UV-visible spectroscopy, the present compound shows indirect allowed transition with an optical band gap (Eg) of around 3.25 eV. The present optical properties of the compound can be utilized in flexible organic electronics applications.

  18. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  19. Parallel optical sampler

    SciTech Connect

    Tauke-Pedretti, Anna; Skogen, Erik J; Vawter, Gregory A

    2014-05-20

    An optical sampler includes a first and second 1.times.n optical beam splitters splitting an input optical sampling signal and an optical analog input signal into n parallel channels, respectively, a plurality of optical delay elements providing n parallel delayed input optical sampling signals, n photodiodes converting the n parallel optical analog input signals into n respective electrical output signals, and n optical modulators modulating the input optical sampling signal or the optical analog input signal by the respective electrical output signals, and providing n successive optical samples of the optical analog input signal. A plurality of output photodiodes and eADCs convert the n successive optical samples to n successive digital samples. The optical modulator may be a photodiode interconnected Mach-Zehnder Modulator. A method of sampling the optical analog input signal is disclosed.

  20. New syntheses of diazo compounds.

    PubMed

    Maas, Gerhard

    2009-01-01

    Diazo compounds (R1R2C=N2) are known as versatile and useful substrates for an array of chemical transformations and, therefore, diazo chemistry is still far from losing anything of its long-standing fascination. In addition to many studies on the subsequent chemistry of the diazo group, the inventory of methods for the preparation of diazo compounds is continuously supplemented by new methods and novel variations of established procedures. Several of these synthetic approaches take into account the lability and remarkable chemical reactivity of certain classes of diazo compounds, and environmentally more benign procedures also continue to be developed. PMID:19790217

  1. Regulation of Compound Leaf Development

    PubMed Central

    Wang, Yuan; Chen, Rujin

    2013-01-01

    Leaf morphology is one of the most variable, yet inheritable, traits in the plant kingdom. How plants develop a variety of forms and shapes is a major biological question. Here, we discuss some recent progress in understanding the development of compound or dissected leaves in model species, such as tomato (Solanum lycopersicum), Cardamine hirsuta and Medicago truncatula, with an emphasis on recent discoveries in legumes. We also discuss progress in gene regulations and hormonal actions in compound leaf development. These studies facilitate our understanding of the underlying regulatory mechanisms and put forward a prospective in compound leaf studies. PMID:27135488

  2. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, Michael S.

    1995-01-01

    A polishing compound for plastic surfaces. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS.TM., LEXAN.TM., LUCITE.TM., polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  3. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1995-08-22

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired. 5 figs.

  4. Polishing compound for plastic surfaces

    SciTech Connect

    Stowell, M.S.

    1993-01-01

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains colloidal silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{sup TM}, LEXAN{sup TM}, LUCITE{sup TM}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  5. Optical instruments

    NASA Technical Reports Server (NTRS)

    Abel, I. R. (Inventor)

    1974-01-01

    A wide angle, low focal ratio, high resolution, catoptric, image plane scanner is described. The scanner includes the following features: (1) a reflective improvement on the Schmidt principle, (2) a polar line scanner in which all field elements are brought to and corrected on axis, and (3) a scanner arrangement in which the aperture stop of the system is imaged at the center of curvature of a spherical primary mirror. The system scans are a large radial angle and an extremely high rate of speed with relatively small scanning mirrors. Because the system is symmetrical about the optical axis, the obscuration is independent of the scan angle.

  6. Optical devices

    DOEpatents

    Chaves, Julio C.; Falicoff, Waqidi; Minano, Juan C.; Benitez, Pablo; Dross, Oliver; Parkyn, Jr., William A.

    2010-07-13

    An optical manifold for efficiently combining a plurality of blue LED outputs to illuminate a phosphor for a single, substantially homogeneous output, in a small, cost-effective package. Embodiments are disclosed that use a single or multiple LEDs and a remote phosphor, and an intermediate wavelength-selective filter arranged so that backscattered photoluminescence is recycled to boost the luminance and flux of the output aperture. A further aperture mask is used to boost phosphor luminance with only modest loss of luminosity. Alternative non-recycling embodiments provide blue and yellow light in collimated beams, either separately or combined into white.

  7. Optical coupling

    NASA Astrophysics Data System (ADS)

    Bock, J. J.; Gundersen, J.; Lee, A. T.; Richards, P. L.; Wollack, E.

    2009-03-01

    This paper describes contributions to the CMBpol Technology Study Workshop concerning optical coupling structures. These are structures in or near the focal plane which convert the free space wave to a superconducting microstrip on a SI wafer, or to the waveguide input to a HEMT receiver. In addition to an introduction and conclusions by the editor, this paper includes independent contributions by Bock on 'Planar Antenna-Coupled Bolometers for CMB Polarimetry', by Gunderson and Wollack on 'Millimeter-Wave Platlet Feeds', and by Lee on 'Multi-band Dual-Polarization Lens-coupled Planar Antennas for Bolometric CMB polarimetry.'

  8. Optical microphone

    DOEpatents

    Veligdan, James T.

    2000-01-11

    An optical microphone includes a laser and beam splitter cooperating therewith for splitting a laser beam into a reference beam and a signal beam. A reflecting sensor receives the signal beam and reflects it in a plurality of reflections through sound pressure waves. A photodetector receives both the reference beam and reflected signal beam for heterodyning thereof to produce an acoustic signal for the sound waves. The sound waves vary the local refractive index in the path of the signal beam which experiences a Doppler frequency shift directly analogous with the sound waves.

  9. Optical switches based on semiconductor optical amplifiers

    NASA Astrophysics Data System (ADS)

    Kalman, Robert F.; Dias, Antonio R.; Chau, Kelvin K.; Goodman, Joseph W.

    1991-12-01

    Fiber-optic switching systems typically exhibit large losses associated with splitting and combining of the optical power, and with excess component losses. These losses increase quickly with switch size. To obtain acceptable signal-to-noise performance through large optical switching, optical amplifiers can be used. In applications requiring optical switching, semiconductor optical amplifiers (SOAs) are preferred over erbium-doped fiber amplifiers due to their fast switching speeds and the possibility of their integration in monolithic structures with passive waveguides and electronics. We present a general analysis of optical switching systems utilizing SOAs. These systems, in which the gain provided by SOAs is distributed throughout the optical system, are referred to as distributed optical gain (DOG) systems. Our model predicts the performance and achievable sizes of switches based on the matrix-vector multiplier crossbar and Benes network. It is found that for realistic SOA parameters optical switches accommodating extremely large numbers of nodes are, in principle, achievable.

  10. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  11. Optical spectroscopy of novel materials

    NASA Astrophysics Data System (ADS)

    Reijnders, Anjan A.

    Optical Spectroscopy is a well-established experimental technique for the study of solids, gasses, and liquids. This thesis focuses on two broad topics related to optical spectroscopy; experimental instrumentation, and its application to novel materials. The first half of the thesis discusses the design and construction of a novel, multifunctional magneto-optical spectroscopy apparatus with exceptional repeatability. Included are the operating principles of FTIR reflectance and transmittance spectroscopy, and the optical ray-tracing design, physical design, and characterization of a custom built magneto-optical spectroscopy apparatus. The second half of the thesis discusses the experimental results of a comprehensive spectroscopic study of Topological Insulators and thermoelectric Pb0.77Sn0.23Se. Topological Insulators (TIs) are a recently discovered phase of matter in which highly conductive free carriers are found on the surface of small band-gap insulators. A challenge in TI research is the experimental isolation of conductive surface states from the bulk states, which are frequently plagued by residual conductivity due to impurities. In this work, optical spectroscopy is used to simultaneously probe the bulk and surface states to study their individual optical properties, in addition to their coupling. Using variable temperature, crystal orientation, and a broad frequency range, we identify compounds with the most resistive bulk states, and provide new insights into carrier dynamics, surface state conductance suppression as a function of temperature, and practical material optimization guidelines for application purposes. A comprehensive optical investigation of Pb0.77Sn0.23Se is also discussed. This is a promising thermoelectric, which exhibits a temperature dependent band inversion, associated with a topological phase transition. We find clear evidence for this band inversion, and find a bulk carrier lifetime dominated by electron-acoustic phonon scattering

  12. Compound cuing in free recall.

    PubMed

    Lohnas, Lynn J; Kahana, Michael J

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity effect should be greater when the 2 most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cuing in both conditional response probabilities and interresponse times. To help rule out a rehearsal-based account of these compound cuing effects, we conducted an experiment with immediate, delayed, and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cuing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

  13. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  14. Optical interconnect assembly

    SciTech Connect

    Laughlin, Daric; Abel, Philip

    2015-06-09

    An optical assembly includes a substrate with a first row of apertures and a second row of apertures. A first optical die includes a first plurality of optical transducer elements and is mounted on the substrate such that an optical signal interface of each transducer element is aligned with an aperture of the first row of optical apertures. A second optical die includes a second plurality of optical transducer elements and is mounted on the substrate such that an optical signal interface of each of the second plurality of optical transducer elements is aligned with an aperture of the second row of optical apertures. A connector configured to mate with the optical assembly supports a plurality of optical fibers. A terminal end of each optical fiber protrudes from the connector and extends into one of the apertures when the connector is coupled with the optical assembly.

  15. Optical recording properties of phthalocyanine copper as a write-once read-many recording medium

    SciTech Connect

    Chen, Q.; Gu, D.; Shu, J.; Tang, X.; Gan, F.

    1994-12-31

    The phthalocyanine compounds have received considerable attention because of their good thermal and chemical stability which ensure a long storage life and high readout times as optical storage media. In this paper, the optical spectra and the complex refractive index of phthalocyanine copper (CuPc) have been studied. The optical recording performances of multilayer films are reported.

  16. Sulfated compounds from marine organisms.

    PubMed

    Kornprobst, J M; Sallenave, C; Barnathan, G

    1998-01-01

    More than 500 sulfated compounds have been isolated from marine organisms so far but most of them originate from two phyla only, Spongia and Echinodermata. The sulfated compounds are presented according to the phyla they have been identified from and to their chemical structures. Biological activities, when available, are also given. Macromolecules have also been included in this review but without structural details. PMID:9530808

  17. Volatile Organic Compounds in Uremia

    PubMed Central

    Seifert, Luzia; Slodzinski, Rafael; Jankowski, Joachim; Zidek, Walter; Westhoff, Timm H.

    2012-01-01

    Background Although “uremic fetor” has long been felt to be diagnostic of renal failure, the compounds exhaled in uremia remain largely unknown so far. The present work investigates whether breath analysis by ion mobility spectrometry can be used for the identification of volatile organic compounds retained in uremia. Methods Breath analysis was performed in 28 adults with an eGFR ≥60 ml/min per 1.73 m2, 26 adults with chronic renal failure corresponding to an eGFR of 10–59 ml/min per 1.73 m2, and 28 adults with end-stage renal disease (ESRD) before and after a hemodialysis session. Breath analysis was performed by ion mobility spectrometryafter gas-chromatographic preseparation. Identification of the compounds of interest was performed by thermal desorption gas chromatography/mass spectrometry. Results Breath analyses revealed significant differences in the spectra of patients with and without renal failure. Thirteen compounds were chosen for further evaluation. Some compounds including hydroxyacetone, 3-hydroxy-2-butanone and ammonia accumulated with decreasing renal function and were eliminated by dialysis. The concentrations of these compounds allowed a significant differentiation between healthy, chronic renal failure with an eGFR of 10–59 ml/min, and ESRD (p<0.05 each). Other compounds including 4-heptanal, 4-heptanone, and 2-heptanone preferentially or exclusively occurred in patients undergoing hemodialysis. Conclusion Impairment of renal function induces a characteristic fingerprint of volatile compounds in the breath. The technique of ion mobility spectrometry can be used for the identification of lipophilic uremic retention molecules. PMID:23049998

  18. Sensing acetylcholine and anticholinesterase compounds.

    PubMed

    Schena, Alberto; Johnsson, Kai

    2014-01-27

    Acetylcholine is a key neurotransmitter, and anticholinesterase agents are essential compounds used as medical drugs, pesticides, and chemical warfare agents. A semisynthetic fluorescence-based probe for the direct, real-time detection of acetylcholine and anticholinesterase compounds is introduced. The probe possesses good sensitivity, tunable detection range, and can be selectively targeted to cell surfaces, thereby making it an attractive tool for applications in analytical chemistry and quantitative biology. PMID:24339043

  19. Aza compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.Q.; McBreen, J.

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

  20. Aza compounds as anion receptors

    DOEpatents

    Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

  1. EDITORIAL: Optical orientation Optical orientation

    NASA Astrophysics Data System (ADS)

    SAME ADDRESS *, Yuri; Landwehr, Gottfried

    2008-11-01

    priority of the discovery in the literature, which was partly caused by the existence of the Iron Curtain. I had already enjoyed contact with Boris in the 1980s when the two volumes of Landau Level Spectroscopy were being prepared [2]. He was one of the pioneers of magneto-optics in semiconductors. In the 1950s the band structure of germanium and silicon was investigated by magneto-optical methods, mainly in the United States. No excitonic effects were observed and the band structure parameters were determined without taking account of excitons. However, working with cuprous oxide, which is a direct semiconductor with a relative large energy gap, Zakharchenya and his co-worker Seysan showed that in order to obtain correct band structure parameters, it is necessary to take excitons into account [3]. About 1970 Boris started work on optical orientation. Early work by Hanle in Germany in the 1920s on the depolarization of luminescence in mercury vapour by a transverse magnetic field was not appreciated for a long time. Only in the late 1940s did Kastler and co-workers in Paris begin a systematic study of optical pumping, which led to the award of a Nobel prize. The ideas of optical pumping were first applied by Georges Lampel to solid state physics in 1968. He demonstrated optical orientation of free carriers in silicon. The detection method was nuclear magnetic resonance; optically oriented free electrons dynamically polarized the 29Si nuclei of the host lattice. The first optical detection of spin orientation was demonstrated by with the III-V semiconductor GaSb by Parsons. Due to the various interaction mechanisms of spins with their environment, the effects occurring in semiconductors are naturally more complex than those in atoms. Optical detection is now the preferred method to detect spin alignment in semiconductors. The orientation of spins in crystals pumped with circularly polarized light is deduced from the degree of circular polarization of the recombination

  2. Optical scanner

    NASA Technical Reports Server (NTRS)

    Finkel, Mitchell W. (Inventor)

    1987-01-01

    An optical scanner for imaging lines in an object plane onto a linear array in a focal plane either continuously or discretely is described. The scanner consists of a set of four mutually perpendicularly oriented plane corner mirrors which provide a reflecting path that describes a parallelogram. In addition, there is a plane parallel scanning mirror with a front and back reflecting surface located midway between the first and fourth corner mirrors. It is oriented so that in the mid-scan position it is parallel to the first corner mirror, and therefore perpendicular to the fourth corner mirror. As the scan mirror rotates, rays incident from a plurality of lines in the object plane are selectively directed through the optical system arriving at a common intersection on the back surface of the scanning mirror where the rays are colinearly directed toward a lens and then imaged onto the linear array in the focal plane. A set of compensating mirrors may be introduced just before the imaging lens to compensate for a small and generally negligible path difference delta sub l between the axial and marginal rays.

  3. Optical Nanodozers

    NASA Astrophysics Data System (ADS)

    Khorshid, Ahmed; Reisner, Walter; Sakaue, Takahiro

    2015-03-01

    Experiment, simulation and scaling analytics are converging on a comprehensive picture regarding the equilibrium behaviour of nanochannel confined semiflexible, self-avoiding chains. Yet, strongly non-equilibrium behaviour of confined polymers is largely unexplored from either an experimental or theoretical point of view. Combining optical trapping and nanofluidics, we have developed a ``nanodozer'' assay for quantifying confined polymer dynamics. An optical trap is used to slide a nanosphere at a fixed velocity along a nanochannel. The trapped bead acts as a permeable gasket, letting fluid escape but preventing the polymer from passing. As the sliding bead comes in contact with a nanochannel extended DNA, the molecule is dynamically compressed, undergoing transient dynamics characterized by a traveling concentration ``shockwave'' before reaching a final steady state with a ramp-like concentration profile. Remarkably, these strongly non-equilibrium measurements can be quantified via a simple nonlinear convective-diffusion formalism and yield insights into the local blob statistics, allowing us to conclude that the compressed nanochannel confined chain exhibits mean-field behaviour.

  4. Optical Instruments

    NASA Astrophysics Data System (ADS)

    1990-01-01

    Precision Lapping and Optical Co. has developed a wide variety of hollow retroreflector systems for applications involving the entire optical spectrum; they are, according to company literature, cheaper, more accurate, lighter and capable of greater size than solid prisms. Precision Lapping's major customers are aerospace and defense companies, government organizations, R&D and commercial instrument companies. For example, Precision Lapping supplies hollow retroreflectors for the laser fire control system of the Army's Abrams tank, and retroreflectors have been and are being used in a number of space tests relative to the Air Force's Strategic Defense Initiative research program. An example of a customer/user is Chesapeake Laser Systems, producer of the Laser Tracker System CMS-2000, which has applications in SDI research and industrial robotics. Another customer is MDA Scientific, Inc., manufacturer of a line of toxic gas detection systems used to monitor hazardous gases present in oil fields, refineries, offshore platforms, chemical plants, waste storage sites and other locations where gases are released into the environment.

  5. Optical diffractometry.

    PubMed

    Tavassoly, M Taghi; Amiri, Mohammad; Darudi, Ahmad; Aalipour, Rasoul; Saber, Ahad; Moradi, Ali-Reza

    2009-03-01

    Interference of light has numerous metrological applications because the optical path difference (OPD) can be varied at will between the interfering waves in the interferometers. We show how one can desirably change the optical path difference in diffraction. This leads to many novel and interesting metrological applications including high-precision measurements of displacement, phase change, refractive index profile, temperature gradient, diffusion coefficient, and coherence parameters, to name only a few. The subject fundamentally differs from interferometry in the sense that in the latter the measurement criterion is the change in intensity or fringe location, while in the former the criterion is the change in the visibility of fringes with an already known intensity profile. The visibility can vary from zero to one as the OPD changes by a half-wave. Therefore, measurements with the accuracy of a few nanometers are quite feasible. Also, the possibility of changing the OPD in diffraction allows us to use Fresnel diffraction in Fourier spectrometry, to enhance or suppress diffracted fields, and to build phase singularities that have many novel and useful applications. PMID:19252652

  6. Interstellar fullerene compounds and diffuse interstellar bands

    NASA Astrophysics Data System (ADS)

    Omont, Alain

    2016-05-01

    . EEHFs, together with pure fullerenes of various sizes, have many properties necessary to be suitably carriers of DIBs: carbonaceous nature; stability and resilience in the harsh conditions of the ISM; existing with various heteroatoms and ionization states; relatively easy formation; few stable isomers; spectral lines in the right spectral range; various and complex energy internal conversion; rich Jahn-Teller fine structure. This is supported by the first identification of a DIB carrier as C60+. Unfortunately, the lack of any precise information about the complex optical spectra of EEHFs and most pure fullerenes other than C60 and about their interstellar abundances still precludes definitive assessment of the importance of fullerene compounds as DIB carriers. Their compounds could significantly contribute to DIBs, but it still seems difficult that they are the only important DIB carriers. Regardless, DIBs appear as the most promising way of tracing the interstellar abundances of various fullerene compounds if the breakthrough in identifying C60+ as a DIB carrier can be extended to more spectral features through systematic studies of their laboratory gas-phase spectroscopy.

  7. Third order optical nonlinearity and optical limiting studies of propane hydrazides

    NASA Astrophysics Data System (ADS)

    Naseema, K.; Manjunatha, K. B.; Sujith, K. V.; Umesh, G.; Kalluraya, Balakrishna; Rao, Vijayalakshmi

    2012-09-01

    Four hydrazones, 2-(4-isobutylphenyl)-N'-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N'-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)-N'-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N'-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient β, magnitude of effective third order susceptibility χ(3), the second order hyperpolarizability γh and the coupling factor ρ have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of β, n2, Re χ(3) and Im χ(3), γh and ρ of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches.

  8. Photochemical dimerization of organic compounds

    SciTech Connect

    Crabtree, R.H.; Brown, S.H.; Muedas, C.A.; Ferguson, R.R.

    1992-04-14

    This patent describes improvement in a Group IIb photosensitized vapor phase dimerization of an organic compound in which a gaseous mixture of a Group IIB metal and the organic compound is irradiated in a reaction zone with a photosensitizing amount of radiant energy. The improvement comprises: a continuous stream of the gaseous mixture is passed as a vapor phase in a single pass through the reaction zone at a temperature at which the thus-produced dimer condenses immediately upon the formation thereof; the starting gaseous mixture comprises hydrogen and two ethylenically unsaturated compounds selected from the group consisting of alkenes of at least six carbon atoms, unsaturated nitriles, unsaturated epoxides, unsaturated silanes, unsaturated amines, unsaturated phosphines, and fluorinated alkenes; the gaseous mixture comprises nitrous oxide and the organic compound is a saturated compound with C-H bond strengths greater than 100 kcal/mol or a mixture of the saturated compound and an alkene; or the starting gaseous comprises an activating amount of hydrogen and the dimerization is a dehydrodimerization or cross-dimerization of a saturated hydrocarbon.

  9. Structural elucidation, optical, magnetic and nonlinear optical properties of oxystyryl dyes.

    PubMed

    Koleva, Bojidarka B; Stoyanov, Stanimir; Kolev, Tsonko; Petkov, Ivan; Spiteller, Michael

    2009-01-01

    Structure, magnetic and optical properties of tetraphenylborate salts of 2,5-[1-methyl-4-[2-(4-hydroxyphenyl)ethenyl]piridinium]-propane and butane are performed in gas and condense phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic liquid crystal suspension, UV-vis and fluorescence methods, HPLC tandem ESI mess spectrometry (MS/MS), (1)H, (13)C and (1)H-(1)H COSY NMR, TGV and DSC methods. Quantum chemical DFT calculations are used for performing of the structures, optical and nonlinear optical properties of the studied compounds. PMID:18722806

  10. Observation of Optical Chemical Shift by Precision Nuclear Spin Optical Rotation Measurements and Calculations.

    PubMed

    Shi, Junhui; Ikäläinen, Suvi; Vaara, Juha; Romalis, Michael V

    2013-02-01

    Nuclear spin optical rotation (NSOR) is a recently developed technique for detection of nuclear magnetic resonance via rotation of light polarization, instead of the usual long-range magnetic fields. NSOR signals depend on hyperfine interactions with virtual optical excitations, giving new information about the nuclear chemical environment. We use a multipass optical cell to perform the first precision measurements of NSOR signals for a range of organic liquids and find clear distinction between proton signals for different compounds, in agreement with our earlier theoretical predictions. Detailed first-principles quantum mechanical NSOR calculations are found to be in agreement with the measurements. PMID:26281737

  11. Structural elucidation, optical, magnetic and nonlinear optical properties of oxystyryl dyes

    NASA Astrophysics Data System (ADS)

    Koleva, Bojidarka B.; Stoyanov, Stanimir; Kolev, Tsonko; Petkov, Ivan; Spiteller, Michael

    2009-01-01

    Structure, magnetic and optical properties of tetraphenylborate salts of 2,5-[1-methyl-4-[2-(4-hydroxyphenyl)ethenyl]piridinium]-propane and butane are performed in gas and condense phase by means of solution and solid-state conventional and linear-polarized IR-spectroscopy of oriented colloids in nematic liquid crystal suspension, UV-vis and fluorescence methods, HPLC tandem ESI mess spectrometry (MS/MS), 1H, 13C and 1H- 1H COSY NMR, TGV and DSC methods. Quantum chemical DFT calculations are used for performing of the structures, optical and nonlinear optical properties of the studied compounds.

  12. Optical Properties of Metallic Nanoparticles

    NASA Astrophysics Data System (ADS)

    Vallée, F.

    The bright and changing colours obtained by dispersing metallic compounds in a glass matrix have been known empirically for centuries. Indeed, glasses have been coloured in the bulk by inclusion of metallic powders since ancient times to make jewellery and ornaments (see Chap. 25). Then in the Middle Ages, they were used for stained glass windows and later on for coloured glass artefacts, e.g., ruby red glass objects. However, the role played by nanoparticles in this colouring effect, i.e., the effects of nanoparticles on optical properties, were only first studied scientifically in the nineteenth century, by Michael Faraday [1].

  13. Optical solitons in liquid crystals

    SciTech Connect

    Yung, Y.S.; Lam, L.; Los Alamos National Lab., NM )

    1989-01-01

    In this paper, we will discuss theoretically the possible existence of optical solitons in the isotropic liquid and in the nematic phase. For the same compound, when heated, the nematic phase will go through a first order transition at temperature T{sub c} to the isotropic liquid phase. As temperature increases from below T{sub c}, the orientation order parameter, Q, decreases, drops to zero abruptly at T{sub c} and remains zero for T > T{sub c}. 10 refs., 1 fig.

  14. Optical sensors in water monitoring

    NASA Astrophysics Data System (ADS)

    Gauglitz, Guenter

    2007-07-01

    An upcoming problem in Europe is the protection of water resources and control of water quality. Coastal areas, rivers, ground water, wetlands, and especially drinking water require permanent monitoring to avoid pollution by small organic molecules or especially endocrine disrupting compounds. Biosensors have demonstrated the proof-of-principle of immunochemistry for these applications. It turns out that especially optical methods based on fluorescence detection can be successfully used for the development of fast, sensitive, cost-effective, and easy-to-use analytical systems meeting the requirements given by European Community Directives and national legislation. Results obtained with the RIANA and AWACSS systems are discussed here.

  15. Optical manifold

    DOEpatents

    Falicoff, Waqidi; Chaves, Julio C.; Minano, Juan Carlos; Benitez, Pablo; Dross, Oliver; Parkyn, Jr., William A.

    2010-02-23

    Optical systems are described that have at least one source of a beam of blue light with divergence under 15.degree.. A phosphor emits yellow light when excited by the blue light. A collimator is disposed with the phosphor and forms a yellow beam with divergence under 15.degree.. A dichroic filter is positioned to transmit the beam of blue light to the phosphor and to reflect the beam of yellow light to an exit aperture. In different embodiments, the beams of blue and yellow light are incident upon said filter with central angles of 15.degree., 22.degree., and 45.degree.. The filter may reflect all of one polarization and part of the other polarization, and a polarization rotating retroreflector may then be provided to return the unreflected light to the filter.

  16. An artificial compound eye system for large field imaging

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Shi, Lifang; Shi, Ruiying; Dong, Xiaochun; Deng, Qiling; Du, Chunlei

    2012-11-01

    With the rapid development of science and technology, optical imaging system has been widely used, and the performance requirements are getting higher and higher such as lighter weight, smaller size, larger field of view and more sensitive to the moving targets. With the advantages of large field of view, high agility and multi-channels, compound eye is more and more concerned by academia and industry. In this work, an artificial spherical compound eye imaging system is proposed, which is formed by several mini cameras to get a large field of view. By analyzing the relationship of the view field between every single camera and the whole system, the geometric arrangement of cameras is studied and the compound eye structure is designed. By using the precision machining technology, the system can be manufactured. To verify the performance of this system, experiments were carried out, where the compound eye was formed by seven mini cameras which were placed centripetally along a spherical surface so that each camera points in a different direction. Pictures taken by these cameras were mosaiced into a complete image with large field of view. The results of the experiments prove the validity of the design method and the fabrication technology. By increasing the number of the cameras, larger view field even panoramic imaging can be realized by using this artificial compound eye.

  17. Method for purifying bidentate organophosphorus compounds

    DOEpatents

    Schulz, Wallace W.

    1977-01-01

    Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds.

  18. Host compounds for red phosphorescent OLEDs

    SciTech Connect

    Xia, Chuanjun; Cheon, Kwang -Ohk

    2015-08-25

    Novel compounds containing a triphenylene moiety linked to an .alpha..beta. connected binaphthyl ring system are provided. These compounds have surprisingly good solubility in organic solvents and are useful as host compounds in red phosphorescent OLEDs.

  19. CALL FOR PAPERS: Optical solitons

    NASA Astrophysics Data System (ADS)

    Drummond, P. D.; Haelterman, Marc; Vilaseca, R.

    2003-06-01

    A topical issue of Journal of Optics B: Quantum and Semiclassical Optics will be devoted to recent advances in optical solitons. The topics to be covered will include, but are not limited to: bulletProperties, control and dynamics of temporal solitons bulletProperties, control and dynamics of spatial solitons bulletCavity solitons in passive and active resonators bulletThree-dimensional spatial solitons bulletDark, bright, grey solitons; interface dynamics bulletCompound or vector solitons; incoherent solitons bulletLight and matter solitons in BEC bulletNonlinear localized structures in microstructured and nanostructured materials (photonic crystals, etc) bulletAngular momentum effects associated with localized light structures; vortex solitons bulletQuantum effects associated with localized light structures bulletInteraction of solitons with atoms and other media bulletApplications of optical solitons The DEADLINE for submission of contributions is 31 July 2003 to allow the topical issue to appear in about February 2004. All papers will be peer-reviewed in accordance with the normal refereeing procedures and standards of Journal of Optics B: Quantum and Semiclassical Optics. Advice on publishing your work in the journal may be found at www.iop.org/journals/authors/jopb. Submissions should ideally be in either standard LaTeX form or Microsoft Word. There are no page charges for publication. In addition to the usual 50 free reprints, the corresponding author of each paper published will receive a complimentary copy of the topical issue. Contributions to the topical issue should if possible be submitted electronically at www.iop.org/journals/jopb. or by e-mail to jopb@iop.org. Authors unable to submit online or by e-mail may send hard copy contributions (enclosing the electronic code) to: Dr Claire Bedrock (Publisher), Journal of Optics B: Quantum and Semiclassical Optics, Institute of Physics Publishing, Dirac House, Temple Back, Bristol BS1 6BE, UK. All

  20. Integrated optics for fiber optic sensors

    NASA Technical Reports Server (NTRS)

    Minford, W. J.; Depaula, R. P.

    1991-01-01

    Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.

  1. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  2. Cytotoxic Compounds from Brucea mollis

    PubMed Central

    Tung, Mai Hung Thanh; Đuc, Ho Viet; Huong, Tran Thu; Duong, Nguyen Thanh; Phuong, Do Thi; Thao, Do Thi; Tai, Bui Huu; Kim, Young Ho; Bach, Tran The; Cuong, Nguyen Manh

    2013-01-01

    Ten compounds, including soulameanone (1), isobruceine B (2), 9-methoxy-canthin-6-one (3), bruceolline F (4), niloticine (5), octatriacontan-1-ol (6), bombiprenone (7), α-tocopherol (8), inosine (9), and apigenin 7-O-β-D-glucopyranoside (10), were isolated from the leaves, stems, and roots of Brucea mollis Wall. ex Kurz. Their structures were determined using one-and two-dimensional NMR spectroscopy and mass spectrometry. All compounds were evaluated for their cytotoxic activity against KB (human carcinoma of the mouth), LU-1 (human lung adenocarcinoma), LNCaP (human prostate adeno-carcinoma), and HL-60 (human promyelocytic leukemia) cancer cell lines. Compound 2 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values of 0.39, 0.40, 0.34, and 0.23 μg/mL, respectively. In addition, compounds 3 and 5 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values around 1–4 μg/mL. Compounds 9-methoxycanthin-6-one (3) and niloticine (5) have been discovered for the first time from the Brucea genus. PMID:24106661

  3. Optical fiber sensing of human skin emanations

    NASA Astrophysics Data System (ADS)

    Lee, S.-W.; Wang, T.; Selyanchyn, R.; Korposh, S.; James, S. W.

    2015-07-01

    An evanescent-wave optical fibre sensor modified with tetrakis(4-sulfophenyl)porphine (TSPP) and poly(allylamine hydrochloride) (PAH) bilayers using an layer-by-layer (LbL) approach was tested to measure the gas emitted from human skin. Optical intensity changes at different wavelengths in the transmission spectrum of the porphyrin-based film were induced by the human skin gas and measured as sensor response. Influence of relative humidity, which can be a major interference to sensor response, was significantly different when compared to the influence of skin emanations. Responses of the current optical sensor system could be considered as composite sensor array, where different optical wavelengths act as channels that have selective response to specific volatile compounds. Data obtained from the sensor system was analyzed through principal component analysis (PCA). This approach enabled to distinguish skin odors of different people and their altered physiological conditions after alcohol consumption.

  4. Integrated resonant micro-optical gyroscope and method of fabrication

    DOEpatents

    Vawter, G. Allen; Zubrzycki, Walter J.; Guo, Junpeng; Sullivan, Charles T.

    2006-09-12

    An integrated optic gyroscope is disclosed which is based on a photonic integrated circuit (PIC) having a bidirectional laser source, a pair of optical waveguide phase modulators and a pair of waveguide photodetectors. The PIC can be connected to a passive ring resonator formed either as a coil of optical fiber or as a coiled optical waveguide. The lasing output from each end of the bidirectional laser source is phase modulated and directed around the passive ring resonator in two counterpropagating directions, with a portion of the lasing output then being detected to determine a rotation rate for the integrated optical gyroscope. The coiled optical waveguide can be formed on a silicon, glass or quartz substrate with a silicon nitride core and a silica cladding, while the PIC includes a plurality of III V compound semiconductor layers including one or more quantum well layers which are disordered in the phase modulators and to form passive optical waveguides.

  5. Microbial Identification in Pharmaceutical Compounding.

    PubMed

    Hyde, Tiffany; Anstead, James; Schade, Lisa; Zellner, James

    2016-01-01

    Compounding pharmacies and contract testing laboratories can readily utilize critical information that microbial identification methods provide. Rapidly identifying the genus and species of environmental isolates and sample contaminates provides pharmacies and laboratories the opportunity to determine the possible source and implement corrective actions to improve compounding and testing processes. The microbial identification data collected from a compounding environment is critical. It is important to have accurate and specific microbial information to guide environmental collection practices, validation studies, and troubleshooting initiatives. The different technologies available provide varying levels of identification. They range from phenotypic assays to more accurate molecular-based techniques, including macromolecular methods and whole genome sequencing. Selecting the appropriate identification methodology requires evaluating multiple factors including the level of information required (genus only, genus and species, etc.) and the pharmacy's tolerance for unidentified or incorrectly identified isolates. PMID:27125052

  6. Antitumor Compounds from Marine Actinomycetes

    PubMed Central

    Olano, Carlos; Méndez, Carmen; Salas, José A.

    2009-01-01

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds. PMID:19597582

  7. Antimicrobial Compounds from Drypetes staudtii.

    PubMed

    Grace, David; Khan, Madiha S; Friesen, Kenneth; Ata, Athar

    2016-07-01

    Antimicrobial-directed phytochemical investigation of the MeOH extract of Drypetes staudtii afforded two new compounds, 4,5-(methylenedioxy)-o-coumaroylputrescine (1), 4,5-(methylenedioxy)-o-coumaroyl-4'-N-methylputrescine (2), along with seven known natural products 4α-hydroxyeremophila-1,9-diene-3,8-dione (3), drypemolundein B (4), friedelan-3β-ol (5), erythrodiol (6), ursolic acid (7), p-coumaric acid (8), and β-sitosterol (9). Structures of compounds 1 - 9 were elucidated with the aid of extensive NMR and mass spectral studies. All of the isolates exhibited antibacterial activity against Gram-positive and Gram-negative bacteria with minimum inhibitory concentration (MIC) in the range of 8 - 128 μg/ml. Compounds 1 - 2 were also moderately active against Candida albicans with an MIC value of 32 μg/ml. PMID:27288642

  8. Gallium-containing anticancer compounds

    PubMed Central

    Chitambar, Christopher R

    2013-01-01

    There is an ever pressing need to develop new drugs for the treatment of cancer. Gallium nitrate, a group IIIa metal salt, inhibits the proliferation of tumor cells in vitro and in vivo and has shown activity against non-Hodgkin’s lymphoma and bladder cancer in clinical trials. Gallium can function as an iron mimetic and perturb iron-dependent proliferation and other iron-related processes in tumor cells. Gallium nitrate lacks cross resistance with conventional chemotherapeutic drugs and is not myelosuppressive; it can be used when other drugs have failed or when the blood count is low. Given the therapeutic potential of gallium, newer generations of gallium compounds are now in various phases of preclinical and clinical development. These compounds hold the promise of greater anti-tumor activity against a broader spectrum of cancers. The development of gallium compounds for cancer treatment and their mechanisms of action will be discussed. PMID:22800370

  9. Optical microactuation in piezoceramics

    NASA Astrophysics Data System (ADS)

    Thakoor, Sarita; Poosanaas, Patcharin; Morookian, John M.; Yavrouian, Andre; Lowry, Lynn; Marzwell, Neville I.; Nelson, Jeffrey G.; Neurgaonkar, Ratnakar R.; Uchino, Kenji

    1998-07-01

    Optically/electrically operable flexible film microactuators that can offer up to two orders high efficiency of photonic to mechanical conversion compared to ceramic actuators are conceptualized. A polarized ceramic wafer of non- centrosymmetric perovskite ferroelectric ABO3 compounds, such as lead lanthanum zirconate titanate (PLZT), when exposed to an illumination (approximately 350 to 400 nm wavelength) close to the bandgap energy, can generate a large photovoltage (approximately 1.0 kV/mm) across its length, and by the inverse piezoelectric effect cause the piezoceramic wafer to deflect in the direction away from the illumination. The optical actuation effect in piezoceramic wafers is investigated as a function of thickness, composition, and surface roughness. Such flexible microactuators would enable a new generation of micro- electro-mechanical and micro-opto-mechanical systems where the actuation will not be restricted by the clamping effect due to the rigid substrate as in the current silicon based micromachined structures. To deposit the piezoceramic film directly onto a flexible substrate, the substrate must have high temperature stability, high strength (Young's Modulus approximately 4.9 X 1010 N/m2), a close match of thermal coefficients of expansion with the piezoceramic film, and a tailorable crystal orientation in order to provide a desired template for growth of oriented PLZT. This paper also presents a comparison of a variety of flexible substrate films and fibers and our recent results on polybenzoxazole (PBO), a polymeric candidate for a flexible high temperature substrate. Variation of the properties of PBO as a function of temperature are also presented.

  10. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  11. Biodegradation of halogenated organic compounds.

    PubMed

    Chaudhry, G R; Chapalamadugu, S

    1991-03-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  12. Integrated optics technology study

    NASA Technical Reports Server (NTRS)

    Chen, B.; Findakly, T.; Innarella, R.

    1982-01-01

    The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given.

  13. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  14. Optical-to-optical interface device

    NASA Technical Reports Server (NTRS)

    Jacobson, A. D.; Bleha, W. P.; Miller, L.; Grinberg, J.; Fraas, L.; Margerum, D.

    1975-01-01

    An investigation was conducted to develop an optical-to-optical interface device capable of performing real-time incoherent-to-incoherent optical image conversion. The photoactivated liquid crystal light valve developed earlier represented a prototype liquid crystal light valve device capable of performing these functions. A device was developed which had high performance and extended lifetime.

  15. Fiber optic monitoring device

    DOEpatents

    Samborsky, J.K.

    1993-10-05

    A device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information. 4 figures.

  16. Fiber optic monitoring device

    SciTech Connect

    Samborsky, J.K.

    1992-12-31

    This invention is comprised of a device for the purpose of monitoring light transmissions in optical fibers comprises a fiber optic tap that optically diverts a fraction of a transmitted optical signal without disrupting the integrity of the signal. The diverted signal is carried, preferably by the fiber optic tap, to a lens or lens system that disperses the light over a solid angle that facilitates viewing. The dispersed light indicates whether or not the monitored optical fiber or system of optical fibers is currently transmitting optical information.

  17. Optical extensometer

    DOEpatents

    Walker, Ray A.; Reich, Fred R.; Russell, James T.

    1978-01-01

    An optical extensometer is described using sequentially pulsed light beams for measuring the dimensions of objects by detecting two opposite edges of the object without contacting the object. The light beams may be of different distinguishable light characteristics, such as polarization or wave length, and are time modulated in an alternating manner at a reference frequency. The light characteristics are of substantially the same total light energy and are distributed symmetrically. In the preferred embodiment two light beam segments of one characteristic are on opposite sides of a middle segment of another characteristic. As a result, when the beam segments are scanned sequentially across two opposite edges of the object, they produce a readout signal at the output of a photoelectric detector that is compared with the reference signal by a phase comparator to produce a measurement signal with a binary level transition when the light beams cross an edge. The light beams may be of different cross sectional geometries, including two superimposed and concentric circular beam cross sections of different diameter, or two rectangular cross sections which intersect with each other substantially perpendicular so only their central portions are superimposed. Alternately, a row of three light beams can be used including two outer beams on opposite sides and separate from a middle beam. The three beams may all be of the same light characteristic. However it is preferable that the middle beam be of a different characteristic but of the same total energy as the two outer beams.

  18. CCAT optics

    NASA Astrophysics Data System (ADS)

    Padin, S.; Hollister, M.; Radford, S.; Sayers, J.; Woody, D.; Zmuidzinas, J.; Cortes-Medellin, G.; Sebring, T.; Stacey, G.

    2010-07-01

    CCAT will be a 25 m diameter, submillimeter-wave telescope. It will be located on Cerro Chajnantor in the Atacama Desert, near ALMA. CCAT will be an on-axis, Ritchey-Chrétien design with an active primary to compensate gravitational deformations. The primary mirror will have 162 segments, each with ~0.5 × 0.5 m reflecting tiles on a ~2×2 m, insulated, carbon-fiber-reinforced-plastic subframe. CCAT will be equipped with wide-field, multi-color cameras and multi-object spectrometers at its Nasmyth foci. These instruments will cover all the atmospheric windows in the λ = 0.2 to 2 mm range. The field of view at the Nasmyth foci will be 1°, so CCAT will be able to support cameras with a few ×104 detectors (spaced 2 beamwidths) at λ = 1 mm to a few ×106 detectors (spaced half a beamwidth) at λ = 350 μm. Single instruments of this size are probably impractical, so we will break the field into smaller pieces, with a separate sub-field camera for each piece. The cameras will require some relay optics to couple the fairly slow beam from the telescope to the detectors. A reflective relay for 1° field of view is too large to be practical, so we plan to use a compact, cold, refractive relay in each sub-field camera.

  19. Illusion optics

    NASA Astrophysics Data System (ADS)

    Lai, Yun; Ng, Jack; Chen, Huan-Yang; Zhang, Zhao-Qing; Chan, C. T.

    2010-09-01

    The technique of “transformation optics” establishes a correspondence between coordinate transformation and material constitutive parameters. Most of the transformation optics mappings give metamaterials that have graded positive refractive indices that can steer light in curves defined by the coordinate transformation. We will focus on those “folded-geometry mappings” that give negative refractive index materials that have special wave scattering properties. One interesting example is a kind of remote illusion device that can transform the stereoscopic image of an object into the illusion of some other object of our choice. The conceptual device can create the illusion without touching or encircling the object. For any incident wave, the device transforms the scattered waves of the original object into that of the object chosen for illusion outside a virtual boundary. We will illustrate some possible applications of this type of metamaterial remote device, including “cloaking at a distance,” partial cloaking, cloaking from an embedded device, revealing a hidden object inside a container, turning the image of one object into that of another object, and seeing through a wall. The feasibility of building this remote illusion device by metamaterials will also be discussed.

  20. Optic neuritis

    PubMed Central

    Pau, D; Al Zubidi, N; Yalamanchili, S; Plant, G T; Lee, A G

    2011-01-01

    Aims The aim of this study is to provide a clinical update on optic neuritis (ON), its association with multiple sclerosis (MS), and neuromyelitis optica (NMO). Methods This study included a PubMed review of the literature written in the English language. Results ON in adults is typically idiopathic or demyelinating, and is characterised by unilateral, subacute, painful loss of vision that is not associated with any systemic or other neurological symptoms. Demyelinating ON is associated with MS, and we review the key studies of ON including the ON treatment trial and several other MS treatment trials and NMO. Conclusion Acute demyelinating ON can occur in isolation or be associated with MS. Typical ON does not require additional evaluation other than cranial magnetic resonance imaging. NMO is likely a separate disorder from MS and the ON in NMO has a different treatment and prognosis. Methodology The authors conducted an English language search using Pubmed from the years 1964 to 2010 using the search terms ‘ON', ‘MS' and ‘NMO'. The authors included original articles, review articles, and case reports, which revealed new aspects as far as epidemiology, histopathology, clinical manifestations, imaging, genetics, and treatment of ON. Titles were reviewed for topicality and full references were obtained. Letters to the editor, unpublished work, and abstracts were not included in this review. PMID:21527960