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Sample records for spinning spectroscopic technique

  1. Fast Hadamard Spectroscopic Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Goelman, G.

    1994-07-01

    Fast Hadamard spectroscopic imaging (HSI) techniques are presented. These techniques combine transverse and longitudinal encoding to obtain multiple-volume localization. The fast techniques are optimized for nuclei with short T2 and long T1 relaxation times and are therefore suitable for in vivo31P spectroscopy. When volume coils are used in fast HSI techniques, the signal-to-noise ratio per unit time (SNRT) is equal to the SNRT in regular HSI techniques. When surface coils are used, fast HSI techniques give significant improvement of SNRT over conventional HSI. Several fast techniques which are different in total experimental time and pulse demands are presented. When the number of acquisitions in a single repetition time is not higher than two, fast HSI techniques can be used with surface coils and the B1 inhomogeneity does not affect the localization. Surface-coil experiments on phantoms and on human calf muscles in vivo are presented. In addition, it is shown that the localization obtained by the HSI techniques are independent of the repetition times.

  2. Spin state transitions in cobaltites: spectroscopic perspective

    NASA Astrophysics Data System (ADS)

    Hao Tjeng, Liu

    2010-03-01

    The class of cobalt-oxide based materials has attracted increasing interest in the last decade. A key aspect of the cobaltites that distinguishes them clearly from the Cu, Ni, and Mn oxides is the spin state degree of freedom of the Co3+ and Co4+ ions: the ions can be low spin, high spin, and perhaps even intermediate spin. This aspect comes on top of the orbital and charge degrees of freedom that already make the Cu, Ni, Mn systems so exciting. It is, however, also precisely this aspect that causes considerable debate in the literature. In this presentation we would like to show how synchrotron based soft-x-ray spectroscopies can successfully resolve the local electronic structure of the Co ions and thus contribute to a better understanding of the physical properties of the cobaltites. In particular, we will address the issue of spin state transitions, metal insulator transitions and the newly proposed spin-blockade phenomenon in several layered cobalt materials. --- Work done in collaboration with Z. Hu, M.W. Haverkort, C.F. Chang, H. Wu, T. Burnus, Y.Y. Chin, N. Hollmann, C. Schussler- Langeheine, M. Benomar, T. Lorenz, D.I. Khomskii (Univ. Cologne), A. Tanaka (Univ. Hiroshima), S.N. Barilo (NAS, Minsk), J. Cezar, N.B. Brookes (ESRF-Grenoble), H.H. Hsieh, H.J. Lin, C.T. Chen (NSRRC-Hsinchu). Supported by the DFG through SFB 608.

  3. Electron Spin Resonance Spectroscopic Studies of Radical Cation Reactions.

    NASA Astrophysics Data System (ADS)

    Dai, Sheng

    1990-01-01

    A spin Hamiltonian suitable for theoretical analyses of ESR spectra in this work is derived by using the general effective Hamiltonian theory in the usual Schrodinger representation. The Permutation Indices method is extended to obtain the dynamic exchange equations used in ESR lineshape simulation. The correlation between beta-hydrogen coupling constants and their geometric orientations is derived through the use of a perturbation method. The three electron bond model is extended to rationalize unimolecular rearrangements of radical cations. The ring-closed radical cations of 9,10-octalin oxide and syn-sesquinorbornene oxide have been characterized by ESR spectroscopy in the CFCl_3 matrix at low temperature. The ESR spectra of the former radical cation exhibit a novel alternating linewidth effect arising from an internal relation between the coupling constants for the four equivalent pairs of hydrogens. The self-electron-transfer rate constants between the methyl viologen dication and cation have been determined by dynamic ESR lineshape simulations at room temperature in allyl alcohol, water, methanol and propargyl alcohol solvents. The radical cation formed by the radiolytic oxidation of allylamine in Freon matrices at 77 K is shown to be the 3-iminiopropyl distonic species(3-iminium-1-propyl radical) resulting from a symmetry-allowed 1,2-hydrogen shift in the parent radical cation. The nucleophilic endocyclization of the but-3-en-1-ol radical cation to the protonated tetrahydrofuran -3-yl radical was observed in the radiolytic oxidation of but-3-en-1-ol in Freon matrices. ESR studies of the radiolytic oxidation of 1,5-hexadiyne have resulted in the first spectroscopic characterization of the radical cation Cope rearrangement, the 1,5-hexadiyne radical cation isomerizing to the 1,2,4,5 -hexatetraene radical cation. ESR studies show that the symmetric(C_{rm 2v}) bicyclo (3.3.0) -octa-2,6-diene-4,8-diyl(a bridged 1,4 -bishomobenzene species) radical cation is

  4. Time-resolved spectroscopic techniques in laser medicine

    NASA Astrophysics Data System (ADS)

    Ortega-Martínez, Roberto; Román-Moreno, Carlos J.; Rodríguez-Rosales, Antonio A.

    2000-10-01

    Spectroscopic lasers techniques are very useful for the detection and treatment of cancer and removing atherosclerotic plaque. Photobiology and photochemical studies, with the new generation of lasers high resolution time-resolved optical tomography is mentioned. A brief review of some of these applications is discussed and a partial list of recent references is given.

  5. MOLECULAR OPTICAL SPECTROSCOPIC TECHNIQUES FOR HAZARDOUS WASTE SITE SCREENING

    EPA Science Inventory

    The U.S. Environmental Protection Agency is interested in field screening hazardous waste sites for contaminants in the soil and surface and ground water. his study is an initial technical overview of the principal molecular spectroscopic techniques and instrumentation currently ...

  6. Spectroscopic Measurement Techniques for Aerospace Flows

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Bathel, Brett F.; Johansen, Craig T.; Cutler, Andrew D.; Hurley, Samantha

    2014-01-01

    The conditions that characterize aerospace flows are so varied, that a single diagnostic technique is not sufficient for its measurement. Fluid dynamists use knowledge of similarity to help categorize and focus on different flow conditions. For example, the Reynolds number represents the ratio of inertial to viscous forces in a flow. When the velocity scales, length scales, and gas density are large and the magnitude of the molecular viscosity is low, the Reynolds number becomes large. This corresponds to large scale vehicles (e.g Airbus A380), fast moving objects (e.g. artillery projectiles), vehicles in dense fluids (e.g. submarine in water), or flows with low dynamic viscosity (e.g. skydiver in air). In each of these cases, the inertial forces dominate viscous forces, and unsteady turbulent fluctuations in the flow variables are observed. In contrast, flows with small length scales (e.g. dispersion of micro-particles in a solid rocket nozzle), slow moving objects (e.g. micro aerial vehicles), flows with low density gases (e.g. atmospheric re-entry), or fluids with a large magnitude of viscosity (e.g. engine coolant flow), all have low Reynolds numbers. In these cases, viscous forces become very important and often the flows can be steady and laminar. The Mach number, which is the ratio of the velocity to the speed of sound in the medium, also helps to differentiate types of flows. At very low Mach numbers, acoustic waves travel much faster than the object, and the flow can be assumed to be incompressible (e.g. Cessna 172 aircraft). As the object speed approaches the speed of sound, the gas density can become variable (e.g. flow over wing of Learjet 85). When the object speed is higher than the speed of sound (Ma > 1), the presences of shock waves and other gas dynamic features can become important to the vehicle performance (e.g. SR-71 Blackbird). In the hypersonic flow regime (Ma > 5), large changes in temperature begin to affect flow properties, causing real

  7. Atmospheric trace gases monitoring by UV-vis spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Xie, Pinhua; Li, Ang; Wu, Fengcheng; Qin, Min; Hu, Rezhi; Xu, Jin; Si, Fuqi; Liu, Jianguo; Liu, Wenqing

    2016-04-01

    Due to rapidly economic development, air pollution has become an important issue in China. Phenomena such as regional haze in winter and high O3 concentration in summer are strongly related to increasing trace species. For better understanding the air pollution formation, it is necessary to know spatial and temporal distribution of trace species in the atmosphere. UV-vis spectroscopic techniques are of great advantages for trace species monitoring to meet several requirements, e.g. versatility, high sensitivity, good temporal resolution and field applicability. We have studied and developed various trace gases monitoring techniques and instruments based on UV-vis spectroscopic technique for in-situ measurements and remote sensing, e.g. LP-DOAS, IBBCEAS, CRDS, MAX-DOAS and mobile DOAS for NO2, SO2, HCHO, HONO, NO3, and N2O5 etc. The principle, instrumentation and inversion algorithm are presented. As typical applications of these techniques, investigation of the evolution of HONO and NO3 radicals over Beijing area, measurements of regional pollution in NCP and YRD are discussed in the aspects of HONO and nocturnal NO3 radical characteristics, trace gases (NO2, SO2 etc.) temporal and spatial distribution, pollution transport pathway, emission sources.

  8. Evaluation of Her2 status using photoacoustic spectroscopic CT techniques

    NASA Astrophysics Data System (ADS)

    Shaffer, Michael; Kruger, Robert; Reinecke, Daniel; Chin-Sinex, Helen; Mendonca, Marc; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to determine the feasibility of using photacoustic CT spectroscopy(PCT-s) to track a near infrared dye conjugated with trastuzumab in vivo. Materials and Methods: An animal model was developed which contained both high and low Her2 expression tumor xenografts on the same mouse. The tumors were imaged at multiple wavelengths (680- 950nm) in the PCT scanner one day prior to injection of the near infrared conjugated probe. Baseline optical imaging data was acquired and the probe was then injected via the tail vein. Fluorescence data was acquired over the next week, PCT spectroscopic data was also acquired during this timeframe. The mice were sacrificed and tumors were extirpated and sent to pathology for IHC staining to verify Her2 expression levels. The optical fluorescence images were analyzed to determine probe uptake dynamics. Reconstructed PCT spectroscopic data was analyzed using IDL routines to deconvolve the probe signal from endogenous background signals, and to determine oxygen saturation. Results: The location of the NIR conjugate was able to be identified within the tumor utilizing IDL fitting routines, in addition oxygen saturation, and hemoglobin concentrations were discernible from the spectroscopic data. Conclusion: Photacoustic spectroscopy allows for the determination of in vivo tumor drug delivery at greater depths than can be determined from optical imaging techniques.

  9. Application of optical spectroscopic techniques for disease diagnosis

    NASA Astrophysics Data System (ADS)

    Saha, Anushree

    Optical spectroscopy, a truly non-invasive tool for remote diagnostics, is capable of providing valuable information on the structure and function of molecules. However, most spectroscopic techniques suffer from drawbacks, which limit their application. As a part of my dissertation work, I have developed theoretical and experimental methods to address the above mentioned issues. I have successfully applied these methods for monitoring the physical, chemical and biochemical parameters of biomolecules involved in some specific life threatening diseases like lead poisoning and age-related macular degeneration (AMD). I presented optical studies of melanosomes, which are one of the vital organelles in the human eye, also known to be responsible for a disease called age-related macular degeneration (AMD), a condition of advanced degeneration which causes progressive blindness. I used Raman spectroscopy, to first chemically identify the composition of melanosome, and then monitor the changes in its functional and chemical behavior due to long term exposure to visible light. The above study, apart from explaining the role of melanosomes in AMD, also sets the threshold power for lasers used in surgeries and other clinical applications. In the second part of my dissertation, a battery of spectroscopic techniques was successfully applied to explore the different binding sites of lead ions with the most abundant carrier protein molecule in our circulatory system, human serum albumin. I applied optical spectroscopic tools for ultrasensitive detection of heavy metal ions in solution which can also be used for lead detection at a very early stage of lead poisoning. Apart from this, I used Raman microspectroscopy to study the chemical alteration occurring inside a prostate cancer cell as a result of a treatment with a low concentrated aqueous extract of a prospective drug, Nerium Oleander. The experimental methods used in this study has tremendous potential for clinical

  10. Employing Multiple Spectroscopic Techniques Simultaneously to Observe Protein Unfolding

    NASA Astrophysics Data System (ADS)

    Crowe, Michael; Kelty, Ben; Link, Justin

    2015-03-01

    A protein's function is directly related to its native, folded structure. In order to study the structure of proteins, the unfolding process may be characterized. In our study, by using the spectroscopic techniques of circular dichroism (CD), absorption, and fluorescence simultaneously, we examined the unfolding of horse heart cytochrome c, a well-studied, model protein by gradually increasing the concentration of the chemical denaturant, guanidine hydrochloride. The signal changes from these modalities over the course of the unfolding reaction provides some of the thermodynamic properties like Gibbs free energy for insight into the stability of the protein. This allows us to compare the three techniques under the exact same conditions. The objective of this session is to present recent work in developing a protocol to observe the unfolding of cytochrome c using fluorescence, absorbance, and CD simultaneously.

  11. New Developments of Broadband Cavity Enhanced Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Walsh, A.; Zhao, D.; Linnartz, H.; Ubachs, W.

    2013-06-01

    In recent years, cavity enhanced spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), cavity enhanced absorption spectroscopy (CEAS), and broadband cavity enhanced absorption spectroscopy (BBCEAS), have been widely employed as ultra-sensitive methods for the measurement of weak absorptions and in the real-time detection of trace species. In this contribution, we introduce two new cavity enhanced spectroscopic concepts: a) Optomechanical shutter modulated BBCEAS, a variant of BBCEAS capable of measuring optical absorption in pulsed systems with typically low duty cycles. In conventional BBCEAS applications, the latter substantially reduces the signal-to-noise ratio (S/N), consequently also reducing the detection sensitivity. To overcome this, we incorporate a fast optomechanical shutter as a time gate, modulating the detection scheme of BBCEAS and increasing the effective duty cycle reaches a value close to unity. This extends the applications of BBCEAS into pulsed samples and also in time-resolved studies. b) Cavity enhanced self-absorption spectroscopy (CESAS), a new spectroscopic concept capable of studying light emitting matter (plasma, flames, combustion samples) simultaneously in absorption and emission. In CESAS, a sample (plasma, flame or combustion source) is located in an optically stable cavity consisting of two high reflectivity mirrors, and here it acts both as light source and absorbing medium. A high detection sensitivity of weak absorption is reached without the need of an external light source, such as a laser or broadband lamp. The performance is illustrated by the first CESAS result on a supersonically expanding hydrocarbon plasma. We expect CESAS to become a generally applicable analytical tool for real time and in situ diagnostics. A. Walsh, D. Zhao, W. Ubachs, H. Linnartz, J. Phys. Chem. A, {dx.doi.org/10.1021/jp310392n}, in press, 2013. A. Walsh, D. Zhao, H. Linnartz Rev. Sci. Instrum. {84}(2), 021608 2013. A. Walsh, D. Zhao

  12. Rapid identification of single microbes by various Raman spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Rösch, Petra; Harz, Michaela; Schmitt, Michael; Peschke, Klaus-Dieter; Ronneberger, Olaf; Burkhardt, Hans; Motzkus, Hans-Walter; Lankers, Markus; Hofer, Stefan; Thiele, Hans; Popp, Jürgen

    2006-02-01

    A fast and unambiguous identification of microorganisms is necessary not only for medical purposes but also in technical processes such as the production of pharmaceuticals. Conventional microbiological identification methods are based on the morphology and the ability of microbes to grow under different conditions on various cultivation media depending on their biochemical properties. These methods require pure cultures which need cultivation of at least 6 h but normally much longer. Recently also additional methods to identify bacteria are established e.g. mass spectroscopy, polymerase chain reaction (PCR), flow cytometry or fluorescence spectroscopy. Alternative approaches for the identification of microorganisms are vibrational spectroscopic techniques. With Raman spectroscopy a spectroscopic fingerprint of the microorganisms can be achieved. Using UV-resonance Raman spectroscopy (UVRR) macromolecules like DNA/RNA and proteins are resonantly enhanced. With an excitation wavelength of e.g. 244 nm it is possible to determine the ratio of guanine/cytosine to all DNA bases which allows a genotypic identification of microorganisms. The application of UVRR requires a large amount of microorganisms (> 10 6 cells) e.g. at least a micro colony. For the analysis of single cells micro-Raman spectroscopy with an excitation wavelength of 532 nm can be used. Here, the obtained information is from all type of molecules inside the cells which lead to a chemotaxonomic identification. In this contribution we show how wavelength dependent Raman spectroscopy yields significant molecular information applicable for the identification of microorganisms on a single cell level.

  13. Spectroscopic evidence for spin-polarized silicon atoms on Si(553)-Au

    SciTech Connect

    Snijders, Paul C; Johnson, P.S.; Guisinger, Nathan; Erwin, S. C.; Himpsel, F.J.

    2012-01-01

    The stepped Si(553)-Au surface undergoes a $1\\times3$ reconstruction at low temperature which has recently been interpreted theoretically as the $\\times3$ ordering of spin-polarized silicon atoms along a step edge in each surface unit cell. This predicted magnetic ground state has a clear spectroscopic signature---a silicon step-edge state at $0.5$ eV above the Fermi level---that arises from strong exchange splitting and hence would not occur without spin polarization. Here we report spatially resolved scanning tunneling spectroscopy data for Si(553)-Au that reveal key differences in the unoccupied step-edge density of states between room temperature and $40$ K. At low temperature we find an unoccupied state at 0.55 eV above every third step-edge silicon atom, in excellent agreement with the spin-polarized ground state predicted theoretically.

  14. Application of Wavelet Unfolding Technique in Neutron Spectroscopic Analysis

    NASA Astrophysics Data System (ADS)

    Hartman, Jessica; Barzilov, Alexander

    Nonproliferation of nuclear materials is important in nuclear power industry and fuel cycle facilities. It requires technologies capable of measuring and assessing the radiation signatures of fission events. Neutrons produced in spontaneous or induced fission reactions are mainly fast. The neutron energy information allows characterization of nuclear materials and neutron sources. It can also be applied in remote sensing and source search tasks. The plastic scintillator EJ-299-33A was studied as a fast neutron detector. The detector response to a polyenergetic flux was unfolded usingthe multiple linear regression method. It yields the intensities of neutron flux of particular energy, hence, enabling the spectroscopic analysis. The wavelet technique was evaluated for the unfolding of neutron spectrum using the scintillator's response functions between 1 MeV and 14 MeV computed with the MCNPX code. This paperpresents the computational results of the wavelet-based spectrum unfolding applied to a scintillator detector with neutron / photon pulse shape discrimination properties.

  15. The VLT-FLAMES Tarantula Survey. XXI. Stellar spin rates of O-type spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Ramírez-Agudelo, O. H.; Sana, H.; de Mink, S. E.; Hénault-Brunet, V.; de Koter, A.; Langer, N.; Tramper, F.; Gräfener, G.; Evans, C. J.; Vink, J. S.; Dufton, P. L.; Taylor, W. D.

    2015-08-01

    Context. The initial distribution of spin rates of massive stars is a fingerprint of their elusive formation process. It also sets a key initial condition for stellar evolution and is thus an important ingredient in stellar population synthesis. So far, most studies have focused on single stars. Most O stars are, however, found in multiple systems. Aims: By establishing the spin-rate distribution of a sizeable sample of O-type spectroscopic binaries and by comparing the distributions of binary subpopulations with one another and with that of presumed-single stars in the same region, we aim to constrain the initial spin distribution of O stars in binaries, and to identify signatures of the physical mechanisms that affect the evolution of the spin rates of massive stars. Methods: We use ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS) to establish the projected equatorial rotational velocities (νesini) for components of 114 spectroscopic binaries in 30 Doradus. The νesini values are derived from the full width at half maximum (FWHM) of a set of spectral lines, using a FWHM vs. νesini calibration that we derive based on previous line analysis methods applied to single O-type stars in the VFTS sample. Results: The overall νesini distribution of the primary stars resembles that of single O-type stars in the VFTS, featuring a low-velocity peak (at νesini< 200 kms-1) and a shoulder at intermediate velocities (200 < νesini< 300 kms-1). The distributions of binaries and single stars, however, differ in two ways. First, the main peak at νesini ~ 100kms-1 is broader and slightly shifted towards higher spin rates in the binary distribution than that of the presumed-single stars. This shift is mostly due to short-period binaries (Porb~< 10 d). Second, the νesini distribution of primaries lacks a significant population of stars spinning faster than 300 kms-1, while such a population is clearly present in the single

  16. Time-resolved infrared spectroscopic techniques as applied to channelrhodopsin

    PubMed Central

    Ritter, Eglof; Puskar, Ljiljana; Bartl, Franz J.; Aziz, Emad F.; Hegemann, Peter; Schade, Ulrich

    2015-01-01

    Among optogenetic tools, channelrhodopsins, the light gated ion channels of the plasma membrane from green algae, play the most important role. Properties like channel selectivity, timing parameters or color can be influenced by the exchange of selected amino acids. Although widely used, in the field of neurosciences for example, there is still little known about their photocycles and the mechanism of ion channel gating and conductance. One of the preferred methods for these studies is infrared spectroscopy since it allows observation of proteins and their function at a molecular level and in near-native environment. The absorption of a photon in channelrhodopsin leads to retinal isomerization within femtoseconds, the conductive states are reached in the microsecond time scale and the return into the fully dark-adapted state may take more than minutes. To be able to cover all these time regimes, a range of different spectroscopical approaches are necessary. This mini-review focuses on time-resolved applications of the infrared technique to study channelrhodopsins and other light triggered proteins. We will discuss the approaches with respect to their suitability to the investigation of channelrhodopsin and related proteins. PMID:26217670

  17. Coupled cluster study of spectroscopic constants of ground states of heavy rare gas dimers with spin-orbit interaction

    NASA Astrophysics Data System (ADS)

    Tu, Zhe-Yan; Wang, Wen-Liang; Li, Ren-Zhong; Xia, Cai-Juan; Li, Lian-Bi

    2016-07-01

    The CCSD(T) approach based on two-component relativistic effective core potential with spin-orbit interaction just included in coupled cluster iteration is adopted to study the spectroscopic constants of ground states of Kr2, Xe2 and Rn2 dimers. The spectroscopic constants have significant basis set dependence. Extrapolation to the complete basis set limit provides the most accurate values. The spin-orbit interaction hardly affects the spectroscopic constants of Kr2 and Xe2. However, the equilibrium bond length is shortened about 0.013 Å and the dissociation energy is augmented about 18 cm-1 by the spin-orbit interaction for Rn2 in the complete basis set limit.

  18. New Techniques for the Next Far Ultraviolet Spectroscopic Mission

    NASA Technical Reports Server (NTRS)

    Green, James C.; Wilkinson, Erik

    2005-01-01

    The Far Ultraviolet Spectroscopic Explorer (FUSE) has been a great success, and has addressed many critical scientific questions (Moos, et al, 2000). However, it has also highlighted the need for even more powerful instrumentation in the 900- 1200 A, regime. In particular, significantly increased effective area will permit the pursuit of additional scientific programs currently impractical or impossible with FUSE. It is unlikely that FUSE will last more than a few more years. Nor is it likely that any large scale UV-optical follow-on to HST (such as SUVO) will include the 900-1200 A, bandpass. However, FUSE remains well oversubscribed and continues to perform excellent science. Therefore, a MIDEX class mission in the next 4-6 years that could significantly improve on the FUSE capabilities would be a powerful scientific tool that would be of great utility to the astronomical community. It would open up new scientific programs if it can improve on the sensitivity of FUSE by an order of magnitude. We have identified a powerful technique for efficient, high-resolution spectroscopy in the FUV (and possibly the EUV) that may provide exactly what is needed for such a mission To achieve a factor of 10 improvement in effective area, we propose using a large (meter class), low-cost, grazing incidence metal optics. This would produced in a manner similar to the EUVE mirrors (Green, et al, 1986), using diamond turning to create the optical figure followed by uncontrolled polishing to achieve a high quality surface. This process will introduce significant figure errors that will degrade the image quality. However, if a holographic grating is employed, which has utilized the actual telescope in the recording geometry, all wavefront errors will be automatically corrected in the end-to-end spectrometer, and high quality spectroscopy will be possible with low quality (and low-cost) optics. In this way a MIDEX class FUSE can be proposed with 10 times the effective area of the

  19. Novel Coherent Laser Spectroscopic Techniques for Minor Species Combustion Diagnostics

    NASA Astrophysics Data System (ADS)

    Mann, Berenice Ann

    Available from UMI in association with The British Library. The aim of this thesis was to research novel coherent laser spectroscopic techniques with the application to combustion diagnostics as a long term objective. Two techniques, Picosecond Absorption Modulated Spectroscopy (PAMS) and Degenerate Four-Wave Mixing Spectroscopy (DFWM), have been experimentally investigated. PAMS is an optical pump-probe type experiment and offers the possibility of making direct, absolute in situ measurements of species concentrations. Results are presented of the PAMS signal against temporal delay for 10^{-6}M rhodamine B solution in methanol, gaseous sodium atoms and in iodine vapour. Iodine was detected at ambient room temperature and atmospheric pressure of air at a concentration of approximately 10ppm. A particular result was the observation of a negative absorption prior to the coherence spike, which has been identified as arising from a coherent transient effect. DFWM has been applied to the measurement of nitrogen dioxide spectra using the pulsed output of a frequency doubled Nd:YAG laser and the tuneable output of an excimer -pumped dye laser DFWM signals have been obtained for the first time in NO_2. Initial characterisation experiments were performed in which DFWM spectra of NO _2 were obtained and identified in the region of 450-480nm. The DFWM signal was investigated as a function of laser intensity, concentration of NO _2 and buffer gas pressure. DFWM has also been demonstrated as a two-dimensional imaging diagnostic in a sodium-seeded premixed acetylene/air slot burner. Further experiments were performed in which single shot DFWM two dimensional images of the distribution of NO_2 in a cold air/NO _2 gas flow have been recorded. Additional images have been obtained of NO_2 doped into a propane-air flame at concentrations of 5000ppm with an estimated spatial resolution of 150 mu m. The images taken in the flame follow the disappearance of NO_2 molecules in the flame

  20. Mean field bipartite spin models treated with mechanical techniques

    NASA Astrophysics Data System (ADS)

    Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Pizzoferrato, Andrea; Tantari, Daniele

    2014-03-01

    Inspired by a continuously increasing interest in modeling and framing complex systems in a thermodynamic rationale, in this paper we continue our investigation in adapting well-known techniques (originally stemmed in fields of physics and mathematics far from the present) for solving for the free energy of mean field spin models in a statistical mechanics scenario. Focusing on the test cases of bipartite spin systems embedded with all the possible interactions (self and reciprocal), we show that both the fully interacting bipartite ferromagnet, as well as the spin glass counterpart, at least at the replica symmetric level, can be solved via the fundamental theorem of calculus, trough an analogy with the Hamilton-Jacobi theory and lastly with a mapping to a Fourier diffusion problem. All these technologies are shown symmetrically for ferromagnets and spin-glasses in full details and contribute as powerful tools in the investigation of complex systems.

  1. Effects of spin-orbit coupling on the electronic states and spectroscopic properties of diatomic SeS

    NASA Astrophysics Data System (ADS)

    Chattopadhyaya, Surya; Nath, Abhijit; Das, Kalyan Kumar

    2016-03-01

    The electronic states and spectroscopic properties of selenium monosulfide (78Se32S) have been studied using relativistic configuration interaction methodology that includes effective core potentials of the constituent atoms. Potential energy curves of several spin-excluded (Λ-S) electronic states have been constructed and spectroscopic constants of low-lying bound Λ-S states within 5.1 eV are reported in the first stage of the calculations. In the next stage, the spin-orbit interaction has been incorporated and its effects on the potential energy curves and spectroscopic properties of the species have been investigated in detail. After the inclusion of spin-orbit coupling, the {{{{X}}}{{1}}}{{3}}{Σ }{0+}- is identified as the spin-orbit (Ω) ground state of the species. The transition moments of several important dipole-allowed and spin-forbidden transitions are calculated and the radiative lifetimes of the excited states involved in the respective transitions are computed. Electric dipole moments (μ z) for some low-lying bound Λ-S states as well as a few low-lying spin-orbit states (Ω-states) are also calculated in the present study.

  2. Laser Spinning: A New Technique for Nanofiber Production

    NASA Astrophysics Data System (ADS)

    Penide, J.; Quintero, F.; del Val, J.; Comesaña, R.; Lusquiños, F.; Riveiro, A.; Pou, J.

    Laser Spinning is a new technique to produce ultralongnanofibers with tailored chemical compositions. In this method, a high power laser is employed to melt a small volume of the precursor material at high temperatures. At the same time, a supersonic gas jet is injected on this molten volume producing its rapid cooling and elongation by viscous friction with the high speed gas flow, hence forming the amorphous nanofibers. This paper collects the main results obtained since the introduction of this technique in 2007.

  3. Optimal and suboptimal control technique for aircraft spin recovery

    NASA Technical Reports Server (NTRS)

    Young, J. W.

    1974-01-01

    An analytic investigation has been made of procedures for effecting recovery from equilibrium spin conditions for three assumed aircraft configurations. Three approaches which utilize conventional aerodynamic controls are investigated. Included are a constant control recovery mode, optimal recoveries, and a suboptimal control logic patterned after optimal recovery results. The optimal and suboptimal techniques are shown to yield a significant improvement in recovery performance over that attained by using a constant control recovery procedure.

  4. Progress in laser-spectroscopic techniques for aerodynamic measurements - An overview

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.

    1991-01-01

    An overview is given of the capabilities and recent progress in laser-spectroscopic measurement techniques for use in aerodynamic test facilities and flight research vehicles. It includes a survey of the literature which is centered on this application of laser spectroscopy. The intended reader is the specialist in experimental fluid dynamics who is not intimately familiar with the physics or applications of laser spectroscopy. Thus, some discussion is also included of the nature of each laser-spectroscopic technique and the practical aspects of its use for aerodynamic measurements. The specific techniques reviewed include laser absorption, laser-induced fluorescence, laser Rayleigh scattering, and laser Raman scattering including spontaneous and coherent processes.

  5. [Clinical applications of arterial spin labeling technique in brain diseases].

    PubMed

    Wang, Li; Zheng, Gang; Zhao, Tiezhu; Guo, Chao; Li, Lin; Lu, Guangming

    2013-02-01

    Arterial spin labeling (ASL) technique is a kind of perfusion functional magnetic resonance imaging method that is based on endogenous contrast, and it can measure cerebral blood flow (CBF) noninvasively. The ASL technique has advantages of noninvasiveness, simplicity and relatively lower costs so that it is more suitable for longitudinal studies compared with previous perfusion methods, such as positron emission tomography (PET), single photon emission computed tomography (SPECT), CT and the contrast agent based magnetic resonance perfusion imaging. This paper mainly discusses the current clinical applications of ASL in brain diseases as cerebrovascular diseases, brain tumors, Alzheimer's disease and epilepsy, etc. PMID:23488163

  6. Theory for the Spin State and Spectroscopic Modes of Multiferroic CaBaCo4O7

    NASA Astrophysics Data System (ADS)

    Fishman, Randy; Bordacs, Sandor; Kezmarki, Istvan; Kocsis, Vilmos; Nagel, Urmas; Room, Toomas; Tokunaga, Y.; Takahashi, Y.; Taguchi, Y.; Tokura, Y.

    With alternating Kagome and triangular lattices, the type I multiferroic CaBaCo4O7 is highly frustrated. Magnetic frustration produces a non-collinear, ferrimagnetic spin state with a net magnetic moment of about 1 mB along the b axis below 60 K. Based on the the field dependence of the three observed spectroscopic modes between 0.8 and 2.7 THz and on the field dependence of the magnetization up to 14 T, we construct a microscopic model for this compound. Using the symmetry of the crystal, the model is constructed in terms of eight independent nearest-neighbor exchange interactions as well as both in-plane and easy-axis anisotropies. With three observed Co species (spins 1.45, 1.0, and 1.2), the magnetic unit cell contains 16 spins. Our results indicate that the easy-plane and hexagonal anisotropy in the triangular layers is far larger than the anisotropy in the kagome layers. The observed spin-induced polarization along the c axis is produced by magnetostriction. We also predict other spin-wave modes outside the window of the spectroscopic measurements. Research Sponsored by the Department of Energy, Office of Sciences, Basic Energy Sciences, Materials Sciences and Engineering Division.

  7. Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T 1) and Spin-Spin (T 2) Relaxation Times

    NASA Astrophysics Data System (ADS)

    Misra, Sushil K.

    The measurement of very short spin-lattice, or longitudinal, relaxation (SLR) times (i.e., 10-10 < T 1 < 10-6 s) is of great importance today for the study of relaxation processes. Recent case studies include, for example, glasses doped with paramagnetic ions (Vergnoux et al., 1996; Zinsou et al., 1996), amorphous Si (dangling bonds) and copper-chromium-tin spinel (Cr3+) (Misra, 1998), and polymer resins doped with rare-earth ions (Pescia et al., 1999a; Pescia et al. 1999b). The ability to measure such fast SLR data on amorphous Si and copper-chromium-tin spinel led to an understanding of the role of exchange interaction in affecting spin-lattice relaxation, while the data on polymer resins doped with rare-earth ions provided evidence of spin-fracton relaxation (Pescia et al., 1999a, b). But such fast SLR times are not measurable by the most commonly used techniques of saturation- and inversion-recovery (Poole, 1982; Alger, 1968), which only measure spin-lattice relaxation times longer than 10-6 s. A summary of relevant experimental data is presented in Table 1.

  8. A spin-drying technique for lyopreservation of mammalian cells.

    PubMed

    Chakraborty, Nilay; Chang, Anthony; Elmoazzen, Heidi; Menze, Michael A; Hand, Steven C; Toner, Mehmet

    2011-05-01

    Stabilization of cellular material in the presence of glass-forming sugars at ambient temperatures is a viable approach that has many potential advantages over current cryogenic strategies. Experimental evidence indicates the possibility to preserve biomolecules in glassy matrices of low-molecular mobility using "glass-forming" sugars like trehalose at ambient temperatures. However, when cells are desiccated in trehalose solution using passive drying techniques, a glassy skin is formed at the liquid/vapor interface of the sample. This glassy skin prevents desiccation of the sample beyond a certain level of dryness and induces non-uniformities in the final water content. Cells trapped underneath this glassy skin may degrade due to a relatively high molecular mobility in the sample. This undesirable result underscores the need for development of a uniform, fast drying technique. In the present study, we report a new technique based on the principles of "spin drying" that can effectively address these problems. Forced convective evaporation of water along with the loss of solution due to centrifugal force leads to rapid vitrification of a thin layer of trehalose containing medium that remains on top of cells attached to the spinning glass substrate. The glassy layer produced has a consistent thickness and a small "surface-area-to-volume" ratio that minimizes any non-homogeneity. Thus, the chance of entrapping cells in a high-mobility environment decreases substantially. We compared numerical predictions to experimental observations of the drying time of 0.2-0.6 M trehalose solutions at a variety of spinning speeds ranging from 1000 to 4000 rpm. The model developed here predicts the formation of sugar films with thicknesses of 200-1000 nm, which was in good agreement with experimental results. Preliminary data suggest that after spin drying cells to about 0.159 ± 0.09 gH₂O/gdw (n = 11, ±SE), more than 95% of cells were able to preserve their membrane integrity

  9. Investigation into Spectroscopic Techniques for Thermal Barrier Coating Spall Detection

    NASA Technical Reports Server (NTRS)

    deGroot, Wim; Opila, Beth

    2001-01-01

    Spectroscopic methods are proposed for detection of thermal barrier coating (TBC) spallation from engine hot zone components. These methods include absorption and emission of airborne marker species originally embedded in the TBC bond coat. In this study, candidate marker materials for this application were evaluated. Thermochemical analysis of candidate marker materials combined with additional constraints such as toxicity and uniqueness to engine environment, provided a short list of four potential species: platinum, copper oxide, zinc oxide. and indium. The melting point of indium was considered to be too low for serious consideration. The other three candidate marker materials, platinum, copper oxide, and zinc oxide were placed in a high temperature furnace and emission and absorption properties were measured over a temperature range from 800-1400 C and a spectral range from 250 to 18000 nm. Platinum did not provide the desired response, likely due to the low vapor Pressure of the metallic species and the low absorption of the oxide species. It was also found, however. that platinum caused a broadening of the carbon dioxide absorption at 4300 nm. The nature of this effect is not known. Absorption and emission caused by sodium and potassium impurities in the platinum were found in the platinum tests. Zinc oxide did not provide the desired response, again, most likely due to the low vapor pressure of the metallic species and the low absorption of the oxide species. Copper oxide generated two strongly temperature dependent absorption peaks at 324.8 and 327.4 nm. The melting point of copper oxide was determined to be too low for serious consideration as marker material.

  10. Spectroscopic Technique for Measuring the Texture of Horticultural Products: Spatially Resolved Approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter reviews the latest developments and applications of spatially resolved spectroscopic techniques for measuring the optical properties and texture or firmness of horticultural products. The chapter first provides a brief overview of the theory of light transfer in turbid biological m...

  11. Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Roldán, Clodoaldo; Juanes, David; Ferrazza, Livio; Carballo, Jorgelina

    2016-02-01

    This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series "Vision of Spain" commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper-arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.

  12. Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

    PubMed Central

    Wang, Chuji; Sahay, Peeyush

    2009-01-01

    Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC) disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS), cavity ringdown spectroscopy (CRDS), integrated cavity output spectroscopy (ICOS), cavity enhanced absorption spectroscopy (CEAS), cavity leak-out spectroscopy (CALOS), photoacoustic spectroscopy (PAS), quartz-enhanced photoacoustic spectroscopy (QEPAS), and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS). Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis. PMID:22408503

  13. Understanding and controlling spin-systems using electron spin resonance techniques

    NASA Astrophysics Data System (ADS)

    Martens, Mathew

    the frequency of this nutation. Experimental findings fit well the analytical model developed. This process could lead to the use of multi-level spin systems as tunable solid state qubits. Finally, if quantum computing technologies are to be commercially realized, an on-chip method to address qubits must be developed. One way to incorporate SMMs to an on-chip device is by way of a coplanar waveguide (CPW) resonator. Efforts to create a resonator of this type to be used to perform low-temperature ESR on-chip will be described. Our work is focused on implementing such on-chip techniques in high magnetic fields, which is desirable for ESR-type of experiments in (quasi-)isotropic spin systems. Considerable attention is given to the coupling of these devices and a geometry is presented for a superconducting CPW resonator that is critically coupled. The effect of the magnetic field on the resonance position and its quality factor is addressed as well. Our devices show robust performance in field upwards of 1 Tesla and their use in performing on-chip ESR measurements seem promising.

  14. Spectroscopic signatures of spin-charge separation in the quasi-one-dimensional organic conductor TTF-TCNQ.

    PubMed

    Claessen, R; Sing, M; Schwingenschlögl, U; Blaha, P; Dressel, M; Jacobsen, C S

    2002-03-01

    The electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ is studied by angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant discrepancies to band theory. We demonstrate that the measured dispersions can be consistently mapped onto the one-dimensional Hubbard model at finite doping. This interpretation is further supported by a remarkable transfer of spectral weight as a function of temperature. The ARPES data thus show spectroscopic signatures of spin-charge separation on an energy scale of the conduction bandwidth. PMID:11864036

  15. Spectroscopic Signatures of Spin-Charge Separation in the Quasi-One-Dimensional Organic Conductor TTF-TCNQ

    NASA Astrophysics Data System (ADS)

    Claessen, R.; Sing, M.; Schwingenschlögl, U.; Blaha, P.; Dressel, M.; Jacobsen, C. S.

    2002-03-01

    The electronic structure of the quasi-one-dimensional organic conductor TTF-TCNQ is studied by angle-resolved photoelectron spectroscopy (ARPES). The experimental spectra reveal significant discrepancies to band theory. We demonstrate that the measured dispersions can be consistently mapped onto the one-dimensional Hubbard model at finite doping. This interpretation is further supported by a remarkable transfer of spectral weight as a function of temperature. The ARPES data thus show spectroscopic signatures of spin-charge separation on an energy scale of the conduction bandwidth.

  16. Site Directed Spin Labeling and EPR Spectroscopic Studies of Pentameric Ligand-Gated Ion Channels.

    PubMed

    Basak, Sandip; Chatterjee, Soumili; Chakrapani, Sudha

    2016-01-01

    Ion channel gating is a stimulus-driven orchestration of protein motions that leads to transitions between closed, open, and desensitized states. Fundamental to these transitions is the intrinsic flexibility of the protein, which is critically modulated by membrane lipid-composition. To better understand the structural basis of channel function, it is necessary to study protein dynamics in a physiological membrane environment. Electron Paramagnetic Resonance (EPR) spectroscopy is an important tool to characterize conformational transitions between functional states. In comparison to NMR and X-ray crystallography, the information obtained from EPR is intrinsically of lower resolution. However, unlike in other techniques, in EPR there is no upper-limit to the molecular weight of the protein, the sample requirements are significantly lower, and more importantly the protein is not constrained by the crystal lattice forces. Therefore, EPR is uniquely suited for studying large protein complexes and proteins in reconstituted systems. In this article, we will discuss general protocols for site-directed spin labeling and membrane reconstitution using a prokaryotic proton-gated pentameric Ligand-Gated Ion Channel (pLGIC) from Gloeobacter violaceus (GLIC) as an example. A combination of steady-state Continuous Wave (CW) and Pulsed (Double Electron Electron Resonance-DEER) EPR approaches will be described that will enable a complete quantitative characterization of channel dynamics. PMID:27403967

  17. Mean field spin glasses treated with PDE techniques

    NASA Astrophysics Data System (ADS)

    Barra, Adriano; Del Ferraro, Gino; Tantari, Daniele

    2013-07-01

    Following an original idea of Guerra, in these notes we analyze the Sherrington-Kirkpatrick model from different perspectives, all sharing the underlying approach which consists in linking the resolution of the statistical mechanics of the model (e.g. solving for the free energy) to well-known partial differential equation (PDE) problems (in suitable spaces). The plan is then to solve the related PDE using techniques involved in their native field and lastly bringing back the solution in the proper statistical mechanics framework. Within this strand, after a streamlined test-case on the Curie-Weiss model to highlight the methods more than the physics behind, we solve the SK both at the replica symmetric and at the 1-RSB level, obtaining the correct expression for the free energy via an analogy to a Fourier equation and for the self-consistencies with an analogy to a Burger equation, whose shock wave develops exactly at critical noise level (triggering the phase transition). Our approach, beyond acting as a new alternative method (with respect to the standard routes) for tackling the complexity of spin glasses, links symmetries in PDE theory with constraints in statistical mechanics and, as a novel result from the theoretical physics perspective, we obtain a new class of polynomial identities (namely of Aizenman-Contucci type, but merged within the Guerra's broken replica measures), whose interest lies in understanding, via the recent Panchenko breakthroughs, how to force the overlap organization to the ultrametric tree predicted by Parisi.

  18. Magnetic and spin transitions in wüstite: A synchrotron Mössbauer spectroscopic study

    NASA Astrophysics Data System (ADS)

    Hamada, Maki; Kamada, Seiji; Ohtani, Eiji; Mitsui, Takaya; Masuda, Ryo; Sakamaki, Tatsuya; Suzuki, Nanami; Maeda, Fumiya; Akasaka, Masahide

    2016-04-01

    This is a Mössbauer study of wüstite at pressures above 200 GPa using synchrotron Mössbauer spectroscopy. Synthetic F e0.96O -wüstite was investigated at 91(2), 95(4), 109(2), 114.5(3), 131.1(7), 133.2(2), 155(2), 167(2), 193(2) and 203(1) GPa at 300 K at the SPring-8 BL11XU beamline. The Mössbauer spectrum at 91 GPa consists of both magnetic and nonmagnetic components. The magnetic high-spin component decreases gradually with increasing pressure from 91 to 203 GPa, while the nonmagnetic low-spin component increases with pressure in the same pressure range. The result suggests that the spin state of Fe in the outer core at pressures above 203 GPa is the low-spin state. If oxygen exists in the core, the low-spin Fe-O bonding is shorter than high-spin Fe-O bonding, suggesting dense Fe-O liquid in the Earth's outer core. The gradual increase of the density of the metallic liquid with depth by the spin transition of Fe-O bonding in the shallow outer core region will stabilize the outer core against thermal convection.

  19. The role of simulation chambers in the development of spectroscopic techniques: campaigns at EUPHORE

    NASA Astrophysics Data System (ADS)

    Ródenas, Milagros; Muñoz, Amalia; Euphore Team

    2016-04-01

    Simulation chambers represent a very useful tool for the study of chemical reactions and their products, but also to characterize instruments. The development of spectroscopic techniques throughout the last decades has benefited from tests and intercomparison exercises carried out in chambers. In fact, instruments can be exposed to various controlled atmospheric scenarios that account for different environmental conditions, eliminating the uncertainties associated to fluctuations of the air mass, which must be taken into account when extrapolating results to the real conditions. Hence, a given instrument can be characterized by assessing its precision, accuracy, detection limits, time response and potential interferences in the presence of other chemical compounds, aerosols, etc. This implies that the instrument can be calibrated and validated, which allows to enhance the features of the instrument. Moreover, chambers are also the scenario of intercomparison trials, permitting multiple instruments to sample from the same well-mixed air mass simultaneously. An overview of different campaigns to characterize and/or intercompare spectroscopic techniques that have taken place in simulation chambers will be given; in particular, those carried out at EUPHORE (two twin domes, 200 m3 each, Spain), where various intercomparison exercises have been deployed under the frame of European projects (e.g. TOXIC, FIONA, PSOA campaigns supported by EUROCHAMP-II). With the common aim of measuring given compounds (e.g. HONO, NO2, OH, glyoxal, m-glyoxal, etc), an important number of spectroscopic instruments and institutions have been involved in chamber experiments, having the chance to intercompare among them and also with other non-spectroscopic systems (e.g. monitors, cromatographs, etc) or model simulations.

  20. Accurate calculations on the 22 electronic states and 54 spin-orbit states of the O2 molecule: potential energy curves, spectroscopic parameters and spin-orbit coupling.

    PubMed

    Liu, Hui; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue; Shulin, Zhang

    2014-04-24

    The potential energy curves (PECs) of 54 spin-orbit states generated from the 22 electronic states of O2 molecule are investigated for the first time for internuclear separations from about 0.1 to 1.0nm. Of the 22 electronic states, the X(3)Σg(-), A(')(3)Δu, A(3)Σu(+), B(3)Σu(-), C(3)Πg, a(1)Δg, b(1)Σg(+), c(1)Σu(-), d(1)Πg, f(1)Σu(+), 1(5)Πg, 1(3)Πu, 2(3)Σg(-), 1(5)Σu(-), 2(1)Σu(-) and 2(1)Δg are found to be bound, whereas the 1(5)Σg(+), 2(5)Σg(+), 1(1)Πu, 1(5)Δg, 1(5)Πu and 2(1)Πu are found to be repulsive ones. The B(3)Σu(-) and d(1)Πg states possess the double well. And the 1(3)Πu, C(3)Πg, A'(3)Δu, 1(5)Δg and 2(5)Σg(+) states are the inverted ones when the spin-orbit coupling is included. The PEC calculations are done by the complete active space self-consistent field (CASSCF) method, which is followed by the internally contracted multireference configuration interaction (icMRCI) approach with the Davidson correction. Core-valence correlation and scalar relativistic corrections are taken into account. The convergence of present calculations is evaluated with respect to the basis set and level of theory. The vibrational properties are discussed for the 1(5)Πg, 1(3)Πu, d(1)Πg and 1(5)Σu(-) states and for the second well of the B(3)Σu(-) state. The spin-orbit coupling effect is accounted for by the state interaction method with the Breit-Pauli Hamiltonian. The PECs of all the electronic states and spin-orbit states are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained, and compared with available experimental and other theoretical results. Analyses demonstrate that the spectroscopic parameters reported here can be expected to be reliably predicted ones. The conclusion is obtained that the effect of spin-orbit coupling on the spectroscopic parameters are small almost for all the electronic states involved in this paper except for the 1(5)Σu(-), 1(5)Πg and 1(3)Πu. PMID:24486866

  1. In situ electron spin resonance and Raman spectroscopic studies of the electrochemical process of conducting polypyrrole films

    SciTech Connect

    Zhong, C.J.; Tian, Z.Q.; Tian, Z.W. )

    1990-03-08

    The electrochemical redox properties of conducting polypyrrole (PPy) films coated on electrodes are investigated in aqueous solutions by use of the in situ techniques of electron spin resonance (ESR) and Raman spectroscopy. Comparisons between the experimental in situ ESR data and a theoretical kinetic prediction on the basis of the polaron-bipolaron model are presented.

  2. Dynamic neutron scattering on incoherent systems using efficient resonance spin flip techniques

    SciTech Connect

    Häussler, Wolfgang; Kredler, Lukas

    2014-05-15

    We have performed numerical ray-tracing Monte-Carlo-simulations of incoherent dynamic neutron scattering experiments. We intend to optimize the efficiency of incoherent measurements depending on the fraction of neutrons scattered without and with spin flip at the sample. In addition to conventional spin echo, we have numerically and experimentally studied oscillating intensity techniques. The results point out the advantages of these different spin echo variants and are an important prerequisite for neutron resonance spin echo instruments like RESEDA (FRM II, Munich), to choose the most efficient technique depending on the scattering vector range and the properties of the sample system under study.

  3. Quantification of UV-Visible and Laser Spectroscopic Techniques for Materials Accountability and Process Control

    SciTech Connect

    Czerwinski, Kenneth; Weck, Phil

    2013-09-13

    Ultraviolet–visible spectroscopy (UV–Visible) and time-resolved laser fluorescence spectroscopy (TRLFS) optical techniques can permit on-line analysis of actinide elements in a solvent extraction process in real time. These techniques have been used for measuring actinide speciation and concentration under laboratory conditions and are easily adaptable to multiple sampling geometries, such as dip probes, fiber-optic sample cells, and flow-through cell geometries. To fully exploit these techniques, researchers must determine the fundamental speciation of target actinides and the resulting influence on spectroscopic properties. Detection limits, process conditions, and speciation of key actinide components can be established and utilized in a range of areas, particularly those related to materials accountability and process control. Through this project, researchers will develop tools and spectroscopic techniques to evaluate solution extraction conditions and concentrations of U, Pu, and Cm in extraction processes, addressing areas of process control and materials accountability. The team will evaluate UV– Visible and TRLFS for use in solvent extraction-based separations. Ongoing research is examining efficacy of UV-Visible spectroscopy to evaluate uranium and plutonium speciation under conditions found in the UREX process and using TRLFS to evaluate Cm speciation and concentration in the TALSPEAK process. A uranyl and plutonium nitrate UV–Visible spectroscopy study met with success, which supports the utility and continued exploration of spectroscopic methods for evaluation of actinide concentrations and solution conditions for other aspects of the UREX+ solvent extraction scheme. This project will examine U and Pu absorbance in TRUEX and TALSPEAK, perform detailed examination of Cm in TRUEX and TALSPEAK, study U laser fluorescence, and apply project data to contactors. The team will also determine peak ratios as a function of solution concentrations for the

  4. One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions

    SciTech Connect

    Sawyer, Karma Rae

    2008-12-01

    Understanding chemical reactions requires the knowledge of the elementary steps of breaking and making bonds, and often a variety of experimental techniques are needed to achieve this goal. The initial steps occur on the femto- through picosecond time-scales, requiring the use of ultrafast spectroscopic methods, while the rate-limiting steps often occur more slowly, requiring alternative techniques. Ultrafast one and two-dimensional infrared and step-scan FTIR spectroscopies are used to investigate the photochemical reactions of four organometallic complexes. The analysis leads to a detailed understanding of mechanisms that are general in nature and may be applicable to a variety of reactions.

  5. Optical detection of middle ear infection using spectroscopic techniques: phantom experiments

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Huang, Jing; Li, Tianqi; Svanberg, Sune; Svanberg, Katarina

    2015-05-01

    A noninvasive optical technique, which is based on a combination of reflectance spectroscopy and gas in scattering media absorption spectroscopy, is demonstrated. It has the potential to improve diagnostics of middle ear infections. An ear phantom prepared with a tissue cavity, which was covered with scattering material, was used for spectroscopic measurements. Diffuse reflectance spectra of the phantom eardrum were measured with a reflectance probe. The presence of oxygen and water vapor as well as gas exchange in the phantom cavity were studied with a specially designed fiber-optic probe for backscattering detection geometry. The results suggest that this method can be developed for improved clinical detection of middle ear infection.

  6. A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

    NASA Astrophysics Data System (ADS)

    Shen, Yujie; Voronine, Dmitri V.; Sokolov, Alexei V.; Scully, Marlan O.

    2015-08-01

    We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

  7. A versatile setup using femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering

    SciTech Connect

    Shen, Yujie; Voronine, Dmitri V.; Sokolov, Alexei V.; Scully, Marlan O.

    2015-08-15

    We report a versatile setup based on the femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman scattering. The setup uses a femtosecond Ti:Sapphire oscillator source and a folded 4f pulse shaper, in which the pulse shaping is carried out through conventional optical elements and does not require a spatial light modulator. Our setup is simple in alignment, and can be easily switched between the collinear single-beam and the noncollinear two-beam configurations. We demonstrate the capability for investigating both transparent and highly scattering samples by detecting transmitted and reflected signals, respectively.

  8. FAST CARS: Engineering a laser spectroscopic technique for rapid identification of bacterial spores

    PubMed Central

    Scully, M. O.; Kattawar, G. W.; Lucht, R. P.; Opatrný, T.; Pilloff, H.; Rebane, A.; Sokolov, A. V.; Zubairy, M. S.

    2002-01-01

    Airborne contaminants, e.g., bacterial spores, are usually analyzed by time-consuming microscopic, chemical, and biological assays. Current research into real-time laser spectroscopic detectors of such contaminants is based on e.g., resonance fluorescence. The present approach derives from recent experiments in which atoms and molecules are prepared by one (or more) coherent laser(s) and probed by another set of lasers. However, generating and using maximally coherent oscillation in macromolecules having an enormous number of degrees of freedom is challenging. In particular, the short dephasing times and rapid internal conversion rates are major obstacles. However, adiabatic fast passage techniques and the ability to generate combs of phase-coherent femtosecond pulses provide tools for the generation and utilization of maximal quantum coherence in large molecules and biopolymers. We call this technique FAST CARS (femtosecond adaptive spectroscopic techniques for coherent anti-Stokes Raman spectroscopy), and the present article proposes and analyses ways in which it could be used to rapidly identify preselected molecules in real time. PMID:12177405

  9. Local Spectroscopic Characterization of Spin and Layer Polarization in WSe2

    NASA Astrophysics Data System (ADS)

    McKenzie, Devin; Yankowitz, Matthew; Leroy, Brian

    Semiconducting transition metal dichalcogenides, such as WSe2, exhibit very strong spin-orbit coupling (SOC) at certain band extrema due to large in-plane dipole moments formed by their heavy constituent atoms. The strong SOC links the spin and valley degrees of freedom in monolayers. In bilayers, interlayer hopping is suppressed by this SOC, leading to a spontaneous layer polarization and a coupling of the layer pseudospin with the spin and valley degrees of freedom. We examine these effects by tracking allowed and forbidden electronic scattering pathways in monolayer and bilayer WSe2 using scanning tunneling spectroscopy. Specifically, we observe a strong suppression of intervalley scattering in both monolayer and bilayer WSe2 indicative of these band polarizations.

  10. Spin and Time-Reversal Symmetries of Superconducting Electron Pairs Probed by the Muon Spin Rotation and Relaxation Technique

    NASA Astrophysics Data System (ADS)

    Higemoto, Wataru; Aoki, Yuji; MacLaughlin, Douglas E.

    2016-09-01

    Unconventional superconductivity based on the strong correlation of electrons is one of the central issues of solid-state physics. Although many experimental techniques are appropriate for investigating unconventional superconductivity, a complete perspective has not been established yet. The symmetries of electron pairs are crucial properties for understanding the essential state of unconventional superconductivity. In this review, we discuss the investigation of the time-reversal and spin symmetries of superconducting electron pairs using the muon spin rotation and relaxation technique. By detecting a spontaneous magnetic field under zero field and/or the temperature dependence of the muon Knight shift in the superconducting phase, the time-reversal symmetry and spin parity of electron pairs have been determined for several unconventional superconductors.

  11. Methodological considerations of electron spin resonance spin trapping techniques for measuring reactive oxygen species generated from metal oxide nanomaterials

    PubMed Central

    Jeong, Min Sook; Yu, Kyeong-Nam; Chung, Hyun Hoon; Park, Soo Jin; Lee, Ah Young; Song, Mi Ryoung; Cho, Myung-Haing; Kim, Jun Sung

    2016-01-01

    Qualitative and quantitative analyses of reactive oxygen species (ROS) generated on the surfaces of nanomaterials are important for understanding their toxicity and toxic mechanisms, which are in turn beneficial for manufacturing more biocompatible nanomaterials in many industrial fields. Electron spin resonance (ESR) is a useful tool for detecting ROS formation. However, using this technique without first considering the physicochemical properties of nanomaterials and proper conditions of the spin trapping agent (such as incubation time) may lead to misinterpretation of the resulting data. In this report, we suggest methodological considerations for ESR as pertains to magnetism, sample preparation and proper incubation time with spin trapping agents. Based on our results, each spin trapping agent should be given the proper incubation time. For nanomaterials having magnetic properties, it is useful to remove these nanomaterials via centrifugation after reacting with spin trapping agents. Sonication for the purpose of sample dispersion and sample light exposure should be controlled during ESR in order to enhance the obtained ROS signal. This report will allow researchers to better design ESR spin trapping applications involving nanomaterials. PMID:27194379

  12. Methodological considerations of electron spin resonance spin trapping techniques for measuring reactive oxygen species generated from metal oxide nanomaterials

    NASA Astrophysics Data System (ADS)

    Jeong, Min Sook; Yu, Kyeong-Nam; Chung, Hyun Hoon; Park, Soo Jin; Lee, Ah Young; Song, Mi Ryoung; Cho, Myung-Haing; Kim, Jun Sung

    2016-05-01

    Qualitative and quantitative analyses of reactive oxygen species (ROS) generated on the surfaces of nanomaterials are important for understanding their toxicity and toxic mechanisms, which are in turn beneficial for manufacturing more biocompatible nanomaterials in many industrial fields. Electron spin resonance (ESR) is a useful tool for detecting ROS formation. However, using this technique without first considering the physicochemical properties of nanomaterials and proper conditions of the spin trapping agent (such as incubation time) may lead to misinterpretation of the resulting data. In this report, we suggest methodological considerations for ESR as pertains to magnetism, sample preparation and proper incubation time with spin trapping agents. Based on our results, each spin trapping agent should be given the proper incubation time. For nanomaterials having magnetic properties, it is useful to remove these nanomaterials via centrifugation after reacting with spin trapping agents. Sonication for the purpose of sample dispersion and sample light exposure should be controlled during ESR in order to enhance the obtained ROS signal. This report will allow researchers to better design ESR spin trapping applications involving nanomaterials.

  13. Methodological considerations of electron spin resonance spin trapping techniques for measuring reactive oxygen species generated from metal oxide nanomaterials.

    PubMed

    Jeong, Min Sook; Yu, Kyeong-Nam; Chung, Hyun Hoon; Park, Soo Jin; Lee, Ah Young; Song, Mi Ryoung; Cho, Myung-Haing; Kim, Jun Sung

    2016-01-01

    Qualitative and quantitative analyses of reactive oxygen species (ROS) generated on the surfaces of nanomaterials are important for understanding their toxicity and toxic mechanisms, which are in turn beneficial for manufacturing more biocompatible nanomaterials in many industrial fields. Electron spin resonance (ESR) is a useful tool for detecting ROS formation. However, using this technique without first considering the physicochemical properties of nanomaterials and proper conditions of the spin trapping agent (such as incubation time) may lead to misinterpretation of the resulting data. In this report, we suggest methodological considerations for ESR as pertains to magnetism, sample preparation and proper incubation time with spin trapping agents. Based on our results, each spin trapping agent should be given the proper incubation time. For nanomaterials having magnetic properties, it is useful to remove these nanomaterials via centrifugation after reacting with spin trapping agents. Sonication for the purpose of sample dispersion and sample light exposure should be controlled during ESR in order to enhance the obtained ROS signal. This report will allow researchers to better design ESR spin trapping applications involving nanomaterials. PMID:27194379

  14. Effects of spin diffusion on electron spin relaxation time measured with a time-resolved microscopic photoluminescence technique

    SciTech Connect

    Ikeda, Kazuhiro Kawaguchi, Hitoshi

    2015-02-07

    We performed measurements at room temperature for a GaAs/AlGaAs multiple quantum well grown on GaAs(110) using a time-resolved microscopic photoluminescence (micro-PL) technique to find what effects spin diffusion had on the measured electron spin relaxation time, τ{sub s}, and developed a method of estimating the spin diffusion coefficient, D{sub s}, using the measured data and the coupled drift-diffusion equations for spin polarized electrons. The spatial nonuniformities of τ{sub s} and the initial degree of electron spin polarization caused by the pump intensity distribution inside the focal spot were taken into account to explain the dependence of τ{sub s} on the measured spot size, i.e., a longer τ{sub s} for a smaller spot size. We estimated D{sub s} as ∼100 cm{sup 2}/s, which is similar to a value reported in the literature. We also provided a qualitative understanding on how spin diffusion lengthens τ{sub s} in micro-PL measurements.

  15. Studies on Nephrite and Jadeite Jades by Fourier Transform Infrared (ftir) and Raman Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Tan, T. L.; Ng, L. L.; Lim, L. C.

    2013-10-01

    The mineralogical properties of black nephrite jade from Western Australia are studied by Fourier transform infrared (FTIR) spectroscopy using both transmission and specular reflectance techniques in the 4000-400 cm-1 wavenumber region. The infrared absorption peaks in the 3700-3600 cm-1 region which are due to the O-H stretching mode provides a quantitative analysis of the Fe/(Fe+Mg) ratio in the mineral composition of jade samples. The Fe/(Fe+Mg) percentage in black nephrite is found to be higher than that in green nephrite, but comparable to that of actinolite (iron-rich nephrite). This implies that the mineralogy of black nephrite is closer to actinolite than tremolite. The jade is also characterized using Raman spectroscopy in the 1200-200 cm-1 region. Results from FTIR and Raman spectroscopic data of black nephrite jade are compared with those of green nephrite jade from New Zealand and jadeite jade from Myanmar. Black nephrite appears to have a slightly different chemical composition from green nephrite. Spectra from FTIR and Raman spectroscopic techniques were found to be useful in differentiating black nephrite, green nephrite, and green jadeite jades. Furthermore, data on refractive index, specific gravity, and hardness of black nephrite jade are measured and compared with those of green nephrite and of jadeite jade.

  16. Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques

    NASA Astrophysics Data System (ADS)

    Du, Yong; Fang, Hong Xia; Zhang, Qi; Zhang, Hui Li; Hong, Zhi

    2016-01-01

    As an important component of double-stranded DNA, adenine has powerful hydrogen-bond capability, due to rich hydrogen bond donors and acceptors existing within its molecular structure. Therefore, it is easy to form cocrystal between adenine and other small molecules with intermolecular hydrogen-bond effect. In this work, cocrystal of adenine and fumaric acid has been characterized as model system by FT-IR and FT-Raman spectral techniques. The experimental results show that the cocrystal formed between adenine and fumaric acid possesses unique spectroscopical characteristic compared with that of starting materials. Density functional theory (DFT) calculation has been performed to optimize the molecular structures and simulate vibrational modes of adenine, fumaric acid and the corresponding cocrystal. Combining the theoretical and experimental vibrational results, the characteristic bands corresponding to bending and stretching vibrations of amino and carbonyl groups within cocrystal are shifted into lower frequencies upon cocrystal formation, and the corresponding bond lengths show some increase due to the effect of intermolecular hydrogen bonding. Different vibrational modes shown in the experimental spectra have been assigned based on the simulation DFT results. The study could provide experimental and theoretical benchmarks to characterize cocrystal formed between active ingredients and cocrystal formers and also the intermolecular hydrogen-bond effect within cocrystal formation process by vibrational spectroscopic techniques.

  17. How to Calculate Spin-Spin Coupling and Spin-Rotation Coupling Strengths and Their Uncertainties from Spectroscopic Data: Application to the c(1^3Σ_g^+) State of Diatomic Lithium

    NASA Astrophysics Data System (ADS)

    Dattani, Nikesh S.; Li, Xuan

    2013-06-01

    Recent high-resolution (± 0.00002 cm^{-1}) photo-association spectroscopy (PAS) data of seven previously unexplored vibrational levels of the 1^3Σ_g^+ state of Li_2 have allowed for the first ever experimental determination of the spin-spin (λ_v) and spin-rotation (γ_v) coupling constants in a diatomic lithium system. For triplet states of diatomic molecules such as the 1^3Σ_g^+ state of Li_2, the three spin-spin/spin-rotation resolved energies associated with a ro-vibrational state |v,N> were expressed explicity in terms of B_v, λ_v, and γ_v in 1929 by Kramer's first-order formulas and then in 1937 by Schlapp's more refined formulas. Given spectroscopic data, while it has never been difficult to extract λ_v and γ_v from Schlapp's formulas, it has been a challenge to reliably predict how accurate these extracted values are. This is for two reasons: (1) the lack of a rigorous method to estimate the uncertainty in B_v, (2) the non-linearity of Schlapp's coupled equations has meant that traditionally they have had to be solved numerically by Newton iterations which makes error propagation difficult. The former challenge has been this year solved by Le Roy with a modification of Hutson's perturbation theory of, and the latter problem has now been solved by symbolic computing software that solves Schlapp's coupled non-linear equations analytically for the first time since their introduction in 1937. M. Semczuk, X. Li, W. Gunton, M. Haw, N. Dattani, J. Witz, A. Mills, D. Jones, K. Madison, Physical Review A {87}, XX (2013) H. Kramers, Zeitschrift fur Physik {53}, 422 (1929) R. Schlapp, Physical Review {51}, 342 (1937) J. Hutson, J. Phys. B, {14}, 851 (1981)

  18. Rhodospirillum rubrum CO-dehydrogenase. Part 2: Spectroscopic investigation and assignment of spin-spin coupling signals

    SciTech Connect

    Heo, J.; Staples, C.R.; Telser, J.; Ludden, P.W.

    1999-12-08

    solely from the [Fe{sub 4}S{sub 4}]{sup 1+} clusters. These resonances are attributed in fully reduced CODH to spin-spin coupling between [Fe{sub 4}S{sub 4}]{sub C}{sup 1+} (S = 1/2) and [Fe{sub 4}S{sub 4}]{sub B}{sup 1+} (S = 1/2). When CODH was poised at a calculated potential of {minus}326 mV, the UV-visible absorption spectrum indicated that only one of the [Fe{sub 4}S{sub 4}] clusters was reduced. However, the EPR spectrum was much different than that observed at ca. {minus}295 mV. The EPR spectrum of CODH at {minus}326 mV exhibited resonances arising from a slow-relaxing [Fe{sub 4}S{sub 4}]{sup 1+} (S = 1/2) cluster (g{sub z,y,x} = 2.04, 1.93, 1.89) and a very minor amount of a fast-relaxing [Fe{sub 4}S{sub 4}]{sup 1+} (S = 1/2) cluster. None of the C{sub red1} coupling signal was present. The fast-relaxing cluster is assigned to [Fe{sub 4}S{sub 4}]{sub C}{sup 1+}, while the slow-relaxing cluster is assigned to uncoupled [Fe{sub 4}S{sub 4}]{sub C}{sup 1+}. The observation of uncoupled [Fe{sub 4}S{sub 4}]{sub C}{sup 1+} at slightly lower potentials suggests the reduction of [(CO{sub L})Fe{sup 3+}-Ni{sup 2+}-H{minus}]{sup 4+} (S = 1/2) to [(CO{sub L})Fe{sup 2+}-Ni{sup 2+}-H{minus}]{sup 3+} (S = 0). Treatment of CODH with its physiological product (CO{sub 2}) while poised at {minus}326 mV with 99% reduced phenosafranin results in accumulation of oxidized dye, the production of CO, and the appearance of a new species with g{sub x} = 1.75. This species has relaxation properties unlike C{sub red2A}. Based upon the method of generation and the relaxation properties of the species, the g = 1.75 feature is assigned to [Fe{sub 4}S{sub 4}]{sub C}{sup 1+} (S = 1/2) spin-coupling with [Fe{sup 2+}-Ni{sup 2+}]{sup 4+} (S = 1) (and is referred to as C{sub red2B}). Based on the data presented in this and Part 1, a mechanism for the oxidation of CO to CO{sub 2} by R.rubrum CODH is proposed.

  19. Implementation of Multiple Spectroscopic Techniques to Simultaneously Observe Native and Mutated Protein Unfolding

    NASA Astrophysics Data System (ADS)

    Cull, Brennan; Ben, Kelty; Link, Justin

    A protein's natural, correctly folded structure can determine the protein's ability to carry out its function. If the unfolding process of proteins can be observed, then the relative stability can be better understood between native and mutated proteins. A global picture of the unfolding process may be completed through the studies of strategically mutated proteins using tryptophan as a probe. Horse heart cytochrome c, a thoroughly studied, model protein was used in our investigation to explore this idea. Various spectroscopic techniques such as circular dichroism (CD), absorbance, and fluorescence were simultaneously applied while slowly unfolding our protein by increasing the concentration of a chemical denaturant, guanidine hydrochloride. This provided us information about the thermodynamic properties of the protein and several mutants which can then be interpreted to gain relative stability information among mutations. Efforts to utilize these techniques on native and mutated proteins in comparison to current scientific unfolding theories will be presented in this session.

  20. Progress towards Single Shot Spectroscopic Techniques for Time-Resolved Measurements in the Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Dalton, Douglas Allen; McWilliams, R. Stewart; Mahmood, M. F.; Goncharov, Alexander F.

    2012-02-01

    We will discuss how we are bridging the gap between static diamond anvil cell and dynamic shock experiments using various spectroscopic techniques which utilize nonlinear optics. Using pulsed laser techniques, we can achieve extreme temperatures while probing optical and chemical changes on fast time scales. Recent developments incorporating broadband spectroscopy into the laser heated diamond anvil cell have indicated that probing phase transitions while measuring temperature is possible [1]. Various methods for incorporating nonlinear vibrational spectroscopy (such as CARS) into the diamond anvil cell will be discussed. The application of these optical diagnostics to pulsed laser heating and table-top shock experiments [2] will be presented. [4pt] [1] R.S. McWilliams et al., in preparation. [0pt] [2] M.R. Armstrong et al., J. Appl. Phys., 108, 023511, (2010).

  1. Spectroscopic Localization by Simultaneous Acquisition of the Double-Spin and Stimulated Echoes

    PubMed Central

    Tal, Assaf; Gonen, Oded

    2014-01-01

    Purpose To design a proton MR spectroscopy (1H-MRS) localization sequence that combines the signal-to-noise-ratio (SNR) benefits of Point Resolved Spectroscopy (PRESS) with the high pulse bandwidths, low chemical shift displacements (CSD), low specific absorption rates (SAR), short echo times (TE) and superior radio-frequency transmit field (B1+) immunity of Stimulated Echo Acquisition Mode (STEAM), by simultaneously refocusing and acquiring both the double-spin and stimulated echo coherence pathways from the volume of interest. Methods We propose a family of 1H-MRS sequences comprising three orthogonal spatially-selective pulses with flip angles 90°<α, β, γ<128°. The stimulated and double-spin echo are refocused in-phase simultaneously by altering the pulses’ phases, flip angles and timing, as well as the inter-pulse gradient spoiling moments. The ≈90° nutations of α, β, γ provide STEAM-like advantages (lower SAR, in-plane CSD and TE; greater B1+ immunity), but with SNRs comparable with PRESS. Results Phantom and in vivo brain experiments show that 83–100% of the PRESS SNR (metabolite-dependent) is achieved at under 75% of the SAR and 66% lower in-plane CSD. Conclusion The advantages of STEAM can be augmented with the higher SNR of PRESS by combining the spin and stimulated echoes. Quantification, especially of J-coupled resonances and intermediate and long TEs, must be carefully considered. PMID:24664399

  2. Positional cues in serial learning: the spin-list technique.

    PubMed

    Kahana, Michael J; Mollison, Matthew V; Addis, Kelly M

    2010-01-01

    To test the hypothesis that serial learning depends largely on the encoding and retrieval of position-to-item associations, we examined whether people can learn spin lists on which starting position is randomly varied across successive learning trials. By turning positional information from a reliable cue into a source of intertrial interference, we expected learning to be greatly impaired. Contrary to this hypothesis, we found that participants were only slightly worse at serial learning under spin conditions and that this impairment reflects a substantial increase in initiation errors coupled with a small increase in intertrial forgetting. These data show that participants can effectively use nonpositional cues when positional cues are unreliable. PMID:19966242

  3. Shape coexistence at low spin in the Z = 50 region and its spectroscopic signatures

    NASA Astrophysics Data System (ADS)

    Garrett, P. E.

    2016-08-01

    Nuclei in the Z = 50 region provide excellent examples of shape coexistence, the establishment of which occurred through the use of detailed spectroscopy, based not only on γ-ray spectroscopy but also conversion electron, particle transfer, Coulomb excitation, and lifetime measurements. The evidence to date strongly suggests that the presence of coexisting shapes arises from the promotion of protons across the Z = 50 closed shell and the strong correlations arising from interplay of the pairing and quadrupole interactions. The evidence for the presence of shape coexistence in the Z = 50 region, at low spin and low excitation energies, will be presented and clues for the microscopic origin explored.

  4. Optical detection of middle ear infection using spectroscopic techniques: phantom experiments.

    PubMed

    Zhang, Hao; Huang, Jing; Li, Tianqi; Svanberg, Sune; Svanberg, Katarina

    2015-05-01

    A noninvasive optical technique, which is based on a combination of reflectance spectroscopy and gas in scattering media absorption spectroscopy, is demonstrated. It has the potential to improve diagnostics of middle ear infections. An ear phantom prepared with a tissue cavity, which was covered with scattering material, was used for spectroscopic measurements. Diffuse reflectance spectra of the phantom eardrum were measured with a reflectance probe. The presence of oxygen and water vapor as well as gas exchange in the phantom cavity were studied with a specially designed fiber-optic probe for backscattering detection geometry. The results suggest that this method can be developed for improved clinical detection of middle ear infection. PMID:25938207

  5. Dielectric studies of boron sub phthalocyanine chloride thin films by admittance spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Kalia, Sameer; Mahajan, Aman; Neerja, Sharma, Anshul Kumar; Kumar, Sanjeev; Bedi, R. K.

    2016-05-01

    The dielectric properties of Boron Sub Phthalocyanine Chloride (Cl-SubPc) thermally deposited on ITO substrate have been studied using admittance spectroscopic techniques. The I-V and capacitance -frequency (C-F) studies at various bias voltages reveal that the mobility of charge carriers decrease with bias voltage, however the conduction phenomenon still remain hopping in nature. From the differential susceptance curve, the contribution of the Schottky barrier contact in the charge carrier concentration was found to be absent. The mobility of charge carriers have been determined using differential susceptance variation and from the phase of admittance curve. The values obtained in two cases have been found to be in agreement with each other.

  6. Spectroscopic Evidence for Strong Quantum Spin Fluctuations with Itinerant Character in YFe2Ge2

    DOE PAGESBeta

    Sirica, N.; Bondino, F.; Nappini, S.; Piz, I.; Poudel, L.; Christianson, Andrew D.; Mandrus, D.; Singh, David J; Mannella, Norman

    2015-03-04

    We report x-ray absorption and photoemission spectroscopy of the electronic structure in the normal state of metallic YFe2Ge2. The data reveal evidence for large fluctuating spin moments on the Fe sites, as indicated by exchange multiplets appearing in the Fe 3s core-level photoemission spectra, even though the compound does not show magnetic order. The magnitude of the multiplet splitting is comparable to that observed in the normal state of the Fe-pnictide superconductors. This shows a connection between YFe2Ge2 and the Fe-based superconductors even though it contains neither pnictogens nor chalcogens. Finally, the implication is that the chemical range of compoundsmore » showing at least one of the characteristic magnetic signatures of the Fe-based superconductors is broader than previously thought.« less

  7. Spin-echo magnetic resonance spectroscopic imaging at 7 T with frequency-modulated refocusing pulses.

    PubMed

    Zhu, He; Soher, Brian J; Ouwerkerk, Ronald; Schär, Michael; Barker, Peter B

    2013-05-01

    Two approaches to high-resolution SENSE-encoded magnetic resonance spectroscopic imaging (MRSI) of the human brain at 7 Tesla (T) with whole-slice coverage are described. Both sequences use high-bandwidth radiofrequency pulses to reduce chemical shift displacement artifacts, SENSE-encoding to reduce scan time, and dual-band water and lipid suppression optimized for 7 T. Simultaneous B0 and transmit B1 mapping was also used for both sequences to optimize field homogeneity using high-order shimming and determine optimum radiofrequency transmit level, respectively. One sequence ("Hahn-MRSI") used reduced flip angle (90°) refocusing pulses for lower radiofrequency power deposition, while the other sequence used adiabatic fast passage refocusing pulses for improved sensitivity and reduced signal dependence on the transmit-B1 level. In four normal subjects, adiabatic fast passage-MRSI showed a signal-to-noise ratio improvement of 3.2±0.5 compared to Hahn-MRSI at the same spatial resolution, pulse repetition time, echo time, and SENSE-acceleration factor. An interleaved two-slice Hahn-MRSI sequence is also demonstrated to be experimentally feasible. PMID:22692894

  8. Nondestructive spectroscopic and imaging techniques for quality evaluation and assessment of fish and fish products.

    PubMed

    He, Hong-Ju; Wu, Di; Sun, Da-Wen

    2015-01-01

    Nowadays, people have increasingly realized the importance of acquiring high quality and nutritional values of fish and fish products in their daily diet. Quality evaluation and assessment are always expected and conducted by using rapid and nondestructive methods in order to satisfy both producers and consumers. During the past two decades, spectroscopic and imaging techniques have been developed to nondestructively estimate and measure quality attributes of fish and fish products. Among these noninvasive methods, visible/near-infrared (VIS/NIR) spectroscopy, computer/machine vision, and hyperspectral imaging have been regarded as powerful and effective analytical tools for fish quality analysis and control. VIS/NIR spectroscopy has been widely applied to determine intrinsic quality characteristics of fish samples, such as moisture, protein, fat, and salt. Computer/machine vision on the other hand mainly focuses on the estimation of external features like color, weight, size, and surface defects. Recently, by incorporating both spectroscopy and imaging techniques in one system, hyperspectral imaging cannot only measure the contents of different quality attributes simultaneously, but also obtain the spatial distribution of such attributes when the quality of fish samples are evaluated and measured. This paper systematically reviews the research advances of these three nondestructive optical techniques in the application of fish quality evaluation and determination and discuss future trends in the developments of nondestructive technologies for further quality characterization in fish and fish products. PMID:24915393

  9. Development of a low resolution (1)H NMR spectroscopic technique for the study of matrix mobility in fresh and freeze-thawed hen egg yolk.

    PubMed

    Au, Carmen; Wang, Tong; Acevedo, Nuria C

    2016-08-01

    Three experiments were conducted in developing a low resolution proton nuclear magnetic resonance ((1)H NMR) spectroscopic technique to study matrix mobility in fresh and freeze-thawed gelled yolk. The Carr-Purcell-Meiboom-Gill (CPMG) sequence was used to measure spin-spin relaxation times of proton pools representing major yolk constituents. A component identification test distinguished 3-4 pools. The least mobile pool was assigned to proteins, protein-lipid and protein-water interactions, and the most mobile to unbound water. The remaining pools were assigned to lipids, lipid-protein and lipid-water interactions. A stability test indicated that yolk had varied matrix mobility within the same sample across five days of refrigeration storage. A reproducibility test demonstrated high repeatability of fresh yolk measurements, but significant differences (p<0.05) were found within gelled yolk samples. This research determined that (1)H NMR spectroscopy, a non-destructive technique, can identify yolk components and detect changes in the matrix. PMID:26988489

  10. Characterizing Si:P quantum dot qubits with spin resonance techniques.

    PubMed

    Wang, Yu; Chen, Chin-Yi; Klimeck, Gerhard; Simmons, Michelle Y; Rahman, Rajib

    2016-01-01

    Quantum dots patterned by atomically precise placement of phosphorus donors in single crystal silicon have long spin lifetimes, advantages in addressability, large exchange tunability, and are readily available few-electron systems. To be utilized as quantum bits, it is important to non-invasively characterise these donor quantum dots post fabrication and extract the number of bound electron and nuclear spins as well as their locations. Here, we propose a metrology technique based on electron spin resonance (ESR) measurements with the on-chip circuitry already needed for qubit manipulation to obtain atomic scale information about donor quantum dots and their spin configurations. Using atomistic tight-binding technique and Hartree self-consistent field approximation, we show that the ESR transition frequencies are directly related to the number of donors, electrons, and their locations through the electron-nuclear hyperfine interaction. PMID:27550779

  11. Characterizing Si:P quantum dot qubits with spin resonance techniques

    PubMed Central

    Wang, Yu; Chen, Chin-Yi; Klimeck, Gerhard; Simmons, Michelle Y.; Rahman, Rajib

    2016-01-01

    Quantum dots patterned by atomically precise placement of phosphorus donors in single crystal silicon have long spin lifetimes, advantages in addressability, large exchange tunability, and are readily available few-electron systems. To be utilized as quantum bits, it is important to non-invasively characterise these donor quantum dots post fabrication and extract the number of bound electron and nuclear spins as well as their locations. Here, we propose a metrology technique based on electron spin resonance (ESR) measurements with the on-chip circuitry already needed for qubit manipulation to obtain atomic scale information about donor quantum dots and their spin configurations. Using atomistic tight-binding technique and Hartree self-consistent field approximation, we show that the ESR transition frequencies are directly related to the number of donors, electrons, and their locations through the electron-nuclear hyperfine interaction. PMID:27550779

  12. Novel techniques for detection and imaging of spin related phenomena: Towards sub-diffraction limited resolution

    NASA Astrophysics Data System (ADS)

    Wolfe, Christopher Stuart

    The idea that the spin degree of freedom of particles can be used to store and transport information has revolutionized the data storage industry and inspired a huge amount of research activity. Spin electronics, or spintronics, provides a plethora of potential improvements to conventional charge electronics that include increased functionality and energy efficiency. Scientists studying spintronics will need a multitude of characterization tools to sensitively detect spins in new materials and devices. There are already a handful of powerful techniques to image spin-related phenomena, but each has limitations. Magnetic resonance force microscopy, for example, offers sensitive detection of spin moments that are localized or nearly so but requires a high vacuum, cryogenic environment. Magnetometry based on nitrogen vacancy centers in diamond is a powerful approach, but requires the nitrogen vacancy center to be in very close contact to the spin system being studied to be able to measure the field generated by the system. Spin-polarized scanning tunneling microscopy provides perhaps the best demonstrated spatial resolution, but typically requires ultrahigh vacuum conditions and is limited to studying the surface of a sample. Traditional optical techniques such as Faraday or Kerr microscopy are limited in spatial resolution by the optical diffraction limit. In this dissertation I will present three new techniques we have developed to address some of these issues and to provide the community with new tools to help push forward spintronics and magnetism related research. I will start by presenting the first experimental demonstration of scanned spin-precession microscopy. This technique has the potential to turn any spin-sensitive detection technique into an imaging platform by providing the groundwork for incorporating a magnetic field gradient with that technique, akin to magnetic resonance imaging, and the mathematical tools to analyze the data and extract the local

  13. Study on the interaction of catechins with human serum albumin using spectroscopic and electrophoretic techniques

    NASA Astrophysics Data System (ADS)

    Trnková, Lucie; Boušová, Iva; Staňková, Veronika; Dršata, Jaroslav

    2011-01-01

    The interaction between eight naturally occurring flavanols (catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate) and human serum albumin (HSA) has been investigated by spectroscopic (fluorescence quenching and UV-Vis absorption) and electrophoretic (native and SDS PAGE) techniques under simulated physiological conditions (pH 7.40, 37 °C). The spectroscopic results confirmed the complex formation for the tested systems. The binding constants and the number of binding sites were obtained by analysis of fluorescence data. The strongest binding affinity to HSA was found for epicatechin gallate and decreased in the order epicatechin gallate ⩾ catechin gallate > epigallocatechin gallate > gallocatechin gallate ≫ epicatechin ⩾ catechin > gallocatechin ⩾ epigallocatechin. All free energy changes possessed negative sign indicating the spontaneity of catechin-HSA systems formation. The binding distances between the donor (HSA) and the acceptors (catechins) estimated by the Förster theory revealed that non-radiation energy transfer from HSA to catechins occurred with high possibility. According to results obtained by native PAGE, the galloylated catechins increased the electrophoretic mobility of HSA, which indicated the change in the molecular charge of HSA, whilst the non-galloylated catechins caused no changes. The ability of aggregation and cross-linking of tested catechins with HSA was not proved by SDS-PAGE. The relationship between the structure characteristics of all tested catechins (e.g. presence of the galloyl moiety on the C-ring, the number of hydroxyl groups on the B-ring, and the spatial arrangement of the substituents on the C-ring) and their binding properties to HSA is discussed. The presented study contributes to the current knowledge in the area of protein-ligand binding, particularly catechin-HSA interactions.

  14. Some flight data extraction techniques used on a general aviation spin research aircraft

    NASA Technical Reports Server (NTRS)

    Sliwa, S. M.

    1979-01-01

    Some methods for obtaining flight data from a highly instrumented general aviation spin research aircraft are developed and illustrated. The required correction terms for the measurement of body accelerations, body velocities, and aircraft orientation are presented. In addition, the equations of motion are utilized to derive total aerodynamic coefficients for comparison with model tests and for analysis. Flight test experience is used to evaluate the utility of various instruments and calculation techniques for spin research.

  15. Infrared spectroscopic investigation of nuclear spin conversion in solid CH{sub 4}

    SciTech Connect

    Sugimoto, Takeru; Yamakawa, Koichiro Arakawa, Ichiro

    2015-12-14

    Infrared spectra of solid CH{sub 4} were studied in the ν{sub 3} and ν{sub 4} vibrational regions. The phase I crystal around 30 K showed broad absorption bands, whereas the phase II crystal at 6.9–10.3 K exhibited splitting of these bands after annealing above 20 K. The split peaks were assigned to the librating and almost freely rotating molecules in phase II on the basis of the peak spacings and time evolution of the peak intensities. From the quantitative analysis of the temporal changes of the R(0) and R(1) peak intensities, the relaxation rates of the numbers of molecules with J = 0 (I = 2) and J = 1 (I = 1) were determined in the temperature range of 6.9–10.3 K. We fitted the function resulting from a combination of direct and indirect relaxation processes mediated by phonons to the temperature dependence of these rates and obtained the activation energies of the indirect process: C ≃ 36 K. Since this value is higher than the energies of perturbed J = 2 states relative to the J = 1 state, we argue that the nuclear spin conversion through the J = 3 state also takes place.

  16. Infrared spectroscopic investigation of nuclear spin conversion in solid CH4

    NASA Astrophysics Data System (ADS)

    Sugimoto, Takeru; Yamakawa, Koichiro; Arakawa, Ichiro

    2015-12-01

    Infrared spectra of solid CH4 were studied in the ν3 and ν4 vibrational regions. The phase I crystal around 30 K showed broad absorption bands, whereas the phase II crystal at 6.9-10.3 K exhibited splitting of these bands after annealing above 20 K. The split peaks were assigned to the librating and almost freely rotating molecules in phase II on the basis of the peak spacings and time evolution of the peak intensities. From the quantitative analysis of the temporal changes of the R(0) and R(1) peak intensities, the relaxation rates of the numbers of molecules with J = 0 (I = 2) and J = 1 (I = 1) were determined in the temperature range of 6.9-10.3 K. We fitted the function resulting from a combination of direct and indirect relaxation processes mediated by phonons to the temperature dependence of these rates and obtained the activation energies of the indirect process: C ≃ 36 K. Since this value is higher than the energies of perturbed J = 2 states relative to the J = 1 state, we argue that the nuclear spin conversion through the J = 3 state also takes place.

  17. Application of spectroscopic techniques for the analysis of kidney stones: a pilot study

    NASA Astrophysics Data System (ADS)

    Shameem, K. M., Muhammed; Chawla, Arun; Bankapur, Aseefhali; Unnikrishnan, V. K.; Santhosh, C.

    2016-03-01

    Identification and characterization of kidney stone remains one of the important analytical tasks in the medical field. Kidney stone is a common health complication throughout the world, which may cause severe pain, obstruction and infection of urinary tract, and can lead to complete renal damage. It commonly occurs in both sexes regardless of age. Kidney stones have different composition, although each stones have a major single characteristic component. A complete understanding of a sample properties and their function can only be feasible by utilizing elemental and molecular information simultaneously. Two laser based analytical techniques; Laser Induced Breakdown spectroscopy (LIBS) and Raman spectroscopy have been used to study different types of kidney stones from different patients. LIBS and Raman spectroscopy are highly complementary spectroscopic techniques, which provide elemental and molecular information of a sample. Q-switched Nd:YAG laser at 355 nm laser having energy 17mJ per pulse at 10 Hz repetition rate was used for getting LIBS spectra. Raman measurements were carried out using a home assembled micro-Raman spectrometer. Using the recorded Raman spectra of kidney stones, we were able to differentiate different kinds of kidney stones. LIBS spectra of the same stones are showing the evidence of C, Ca, H, and O and also suggest the presence of certain pigments.

  18. Intratumoral Agreement of High-Resolution Magic Angle Spinning Magnetic Resonance Spectroscopic Profiles in the Metabolic Characterization of Breast Cancer

    PubMed Central

    Park, Vivian Youngjean; Yoon, Dahye; Koo, Ja Seung; Kim, Eun-Kyung; Kim, Seung Il; Choi, Ji Soo; Park, Seho; Park, Hyung Seok; Kim, Suhkmann; Kim, Min Jung

    2016-01-01

    Abstract High-resolution magic angle spinning (HR-MAS) magnetic resonance (MR) spectroscopy data may serve as a biomarker for breast cancer, with only a small volume of tissue sample required for assessment. However, previous studies utilized only a single tissue sample from each patient. The aim of this study was to investigate whether intratumoral location and biospecimen type affected the metabolic characterization of breast cancer assessed by HR-MAS MR spectroscopy This prospective study was approved by the institutional review board and informed consent was obtained. Preoperative core-needle biopsies (CNBs), central, and peripheral surgical tumor specimens were prospectively collected under ultrasound (US) guidance in 31 patients with invasive breast cancer. Specimens were assessed with HR-MAS MR spectroscopy. The reliability of metabolite concentrations was evaluated and multivariate analysis was performed according to intratumoral location and biospecimen type. There was a moderate or higher agreement between the relative concentrations of 94.3% (33 of 35) of metabolites in the center and periphery, 80.0% (28 of 35) of metabolites in the CNB and central surgical specimens, and 82.9% (29 of 35) of metabolites between all 3 specimen types. However, there was no significant agreement between the concentrations of phosphocholine (PC) and phosphoethanolamine (PE) in the center and periphery. The concentrations of several metabolites (adipate, arginine, fumarate, glutamate, PC, and PE) had no significant agreement between the CNB and central surgical specimens. In conclusion, most HR-MAS MR spectroscopic data do not differ based on intratumoral location or biospecimen type. However, some metabolites may be affected by specimen-related variables, and caution is recommended in decision-making based solely on metabolite concentrations, particularly PC and PE. Further validation through future studies is needed for the clinical implementation of these biomarkers based

  19. Optical waveguide lightmode spectroscopic techniques for investigating membrane-bound ion channel activities.

    PubMed

    Székács, Inna; Kaszás, Nóra; Gróf, Pál; Erdélyi, Katalin; Szendrő, István; Mihalik, Balázs; Pataki, Agnes; Antoni, Ferenc A; Madarász, Emilia

    2013-01-01

    Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET) mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na(+) and organic cations through gramicidin channels and detecting the Cl(-)-channel functions of the (α5β2γ2) GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline. PMID:24339925

  20. Spectroscopic technique with wide range of wavelength information improves near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Eda, Hideo; Aoki, Hiromichi; Eura, Shigeru; Ebe, Kazutoshi

    2009-02-01

    Near-infrared spectroscopy (NIRS) calculates hemoglobin parameters, such as oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) using the near-infrared light around the wavelength of 800nm. This is based on the modified-Lambert-Beer's law that changes in absorbance are proportional to changes in hemoglobin parameters. Many conventional measurement methods uses only a few wavelengths, however, in this research, basic examination of NIRS measurement was approached by acquiring wide range of wavelength information. Venous occlusion test was performed by using the blood pressure cuff around the upper arm. Pressure of 100mmHg was then applied for about 3 minutes. During the venous occlusion, the spectrum of the lower arm muscles was measured every 15 seconds, within the range of 600 to 1100nm. It was found that other wavelength bands hold information correlating to this venous occlusion task. Technique of improving the performance of NIRS measurement using the Spectroscopic Method is very important for Brain science.

  1. Soil examination for a forensic trace evidence laboratory--Part 1: Spectroscopic techniques.

    PubMed

    Woods, Brenda; Lennard, Chris; Kirkbride, K Paul; Robertson, James

    2014-12-01

    In the past, forensic soil examination was a routine aspect of trace evidence examination in forensic science. However, in Australia, the apparent need for soil examinations has diminished and with it the capability of forensic science laboratories to carry out soil examination has been eroded. In recent years, due to soil examinations contributing to some high profile investigations, interest in soil examinations has been renewed. Routine soil examinations conducted in a forensic science laboratory by trace evidence scientists can be facilitated if the examinations are conducted using the instrumentation routinely used by these examiners. Spectroscopic techniques such as visible microspectrophotometry (MSP) and Attenuated Total Reflectance (ATR) Fourier Transform Infrared spectroscopy (FTIR) are routinely used by trace evidence analysts for the colour and compositional analysis, respectively, of forensic items, including paints, fibres, inks and toners, tapes, adhesives and other miscellaneous examinations. This article presents an examination of the feasibility of using MSP and ATR-FTIR as a first step in the forensic comparison of soils with particular reference to Australian soil samples. This initial study demonstrates MSP and ATR-FTIR can effectively be used as a screening test for the discrimination of "forensic-sized" soil samples prior to submission for more detailed analyses by a soil expert. PMID:25205526

  2. Structural studies of E. coli ribosomes by spectroscopic techniques: A specialized review

    NASA Astrophysics Data System (ADS)

    Bonicontro, Adalberto; Risuleo, Gianfranco

    2005-12-01

    We present a review on our interdisciplinary line of research based on strategies of molecular biology and biophysics. These have been applied to the study of the prokaryotic ribosome of the bacterium Escherichia coli. Our investigations on this organelle have continued for more than a decade and we have adopted different spectroscopic biophysical techniques such as: dielectric and fluorescence spectroscopy as well as light scattering (photon correlation spectroscopy). Here we report studies on the whole 70S ribosomes and on the separated subunits 30S and 50S. Our results evidence intrinsic structural features of the subunits: the small shows a more "floppy" structure, while the large one appears to be more rigid. Also, an inner "kernel" formed by the RNA/protein association is found within the ribosome. This kernel is surrounded by a ribonucleoprotein complex more exposed to the solvent. Initial analyses were done on the so called Kaldtschmit-Wittmann ribosome: more recently we have extended the studies to the "tight couple" ribosome known for its better functional performance in vitro. Data evidence a phenomenological correlation between the differential biological activity and the intrinsic structural properties of the two-ribosome species. Finally, investigations were also conducted on particles treated at sub-denaturing temperatures and on ribosomes partially deproteinized by salt treatment (ribosomal cores). Results suggest that the thermal treatment and the selective removal of proteins cause analogous structural alterations.

  3. Investigation of fungal deterioration of synthetic paint binders using vibrational spectroscopic techniques.

    PubMed

    Cappitelli, Francesca; Vicini, Silvia; Piaggio, Paolo; Abbruscato, Pamela; Princi, Elisabetta; Casadevall, Arturo; Nosanchuk, Joshua D; Zanardini, Elisabetta

    2005-01-14

    The deterioration of synthetic polymers caused by biological process is usually evaluated by visual inspection and measuring physical effects. In contrast to this approach, we have applied vibrational spectroscopies to study the biodegradation of the synthetic resins. 29 synthetic resins used as paint binding media, including acrylic, alkyd and poly(vinyl acetate) polymers, were examined for potential susceptibility to fungal degradation using the standard method ASTM G21-96(2002). In addition, the degraded resins were analysed by Raman spectroscopy, FT-IR and FT-IR photoacoustic spectroscopy. Almost all the acrylic resins studied proved to be resistant to microbial attack, while all alkyd resins and some poly(vinyl acetates) turned out to be biodegradable. Within a few days of inoculation Aspergillus niger was the most copious fungus on the biodegraded resins. A comparison of the IR and Raman spectra of control and biodegraded resins did not show any differences, but photoacoustic spectroscopy revealed additional bands for the fungal-degraded resins, consistent with the presence of fungal-derived substances. The additional bands in the photoacoustic spectra were due to the presence of Aspergillus niger and melanin, a fungal pigment. Since IR photoacoustic spectroscopy can be also a suitable technique for the chemical characterisation of binding media, the same spectroscopic analysis can be employed to both characterise the material and obtain evidence for fungal colonization. Microbial growth on Sobral 1241ML (alkyd resin) after 28 d (growth rating 4) compared with the non-inoculated resin. PMID:15635715

  4. Optical Waveguide Lightmode Spectroscopic Techniques for Investigating Membrane-Bound Ion Channel Activities

    PubMed Central

    Székács, Inna; Kaszás, Nóra; Gróf, Pál; Erdélyi, Katalin; Szendrő, István; Mihalik, Balázs; Pataki, Ágnes; Antoni, Ferenc A.; Madarász, Emilia

    2013-01-01

    Optical waveguide lightmode spectroscopic (OWLS) techniques were probed for monitoring ion permeation through channels incorporated into artificial lipid environment. A novel sensor set-up was developed by depositing liposomes or cell-derived membrane fragments onto hydrophilic polytetrafluoroethylene (PTFE) membrane. The fibrous material of PTFE membrane could entrap lipoid vesicles and the water-filled pores provided environment for the hydrophilic domains of lipid-embedded proteins. The sensor surface was kept clean from the lipid holder PTFE membrane by a water- and ion-permeable polyethylene terephthalate (PET) mesh. The sensor set-up was tested with egg yolk lecithin liposomes containing gramicidin ion channels and with cell-derived membrane fragments enriched in GABA-gated anion channels. The method allowed monitoring the move of Na+ and organic cations through gramicidin channels and detecting the Cl–-channel functions of the (α5β2γ2) GABAA receptor in the presence or absence of GABA and the competitive GABA-blocker bicuculline. PMID:24339925

  5. A computationally assisted spectroscopic technique to measure secondary electron emission coefficients in radio frequency plasmas

    NASA Astrophysics Data System (ADS)

    Daksha, M.; Berger, B.; Schuengel, E.; Korolov, I.; Derzsi, A.; Koepke, M.; Donkó, Z.; Schulze, J.

    2016-06-01

    A computationally assisted spectroscopic technique to measure secondary electron emission coefficients (γ-CAST) in capacitively-coupled radio-frequency plasmas is proposed. This non-intrusive, sensitive diagnostic is based on a combination of phase resolved optical emission spectroscopy and particle-based kinetic simulations. In such plasmas (under most conditions in electropositive gases) the spatio-temporally resolved electron-impact excitation/ionization rate features two distinct maxima adjacent to each electrode at different times within each RF period. While one maximum is the consequence of the energy gain of electrons due to sheath expansion, the second maximum is produced by secondary electrons accelerated towards the plasma bulk by the sheath electric field at the time of maximum voltage drop across the adjacent sheath. Due to these different excitation/ionization mechanisms, the ratio of the intensities of these maxima is very sensitive to the secondary electron emission coefficient γ. This sensitvity, in turn, allows γ to be determined by comparing experimental excitation profiles and simulation data obtained with various γ-coefficients. The diagnostic, tested here in a geometrically symmetric argon discharge, yields an effective secondary electron emission coefficient of γ =0.066+/- 0.01 for stainless steel electrodes.

  6. Integrated Analysis of the Wood Oil from Xanthocyparis vietnamensis Farjon & Hiep. by Chromatographic and Spectroscopic Techniques.

    PubMed

    Bazzali, Ophélie; Thai, Tran Huy; Hoi, Tran Minh; Khang, Nguyen Sinh; Hien, Nguyen Thi; Casanova, Joseph; Bighelli, Ange; Tomi, Félix

    2016-01-01

    In order to get better knowledge about the volatiles produced by Xanthocyparis vietnamensis, a species recently discovered in Vietnam, its wood oil has been analyzed by a combination of chromatographic (GC, CC) and spectroscopic (GC-MS, (13)C-NMR) techniques. Forty components that accounted for 87.9% of the oil composition have been identified. The composition is dominated by nootkatene (20.7%), 11,12,13-tri-nor-eremophil-1(10)-en-7-one (17.2%), γ-eudesmol (5.1%), nootkatone (4.7%), valencene (3.5%) and 13-nor-eremophil-1(10)-en-11-one (2.6%). The structure of two new compounds-10-epi-nor-γ-eudesmen-11-one and 12-hydroxy-isodihydroagarofuran-has been elucidated, while 11,12,13-tri-nor-eremophil-1(10)-en-7-ol is reported as a natural product for the first time. The composition of X. vietnamensis wood oil varied drastically from those of leaf oils, dominated by hedycaryol (34.4%), phyllocladene (37.8%) or by pimara-6(14)-15-diene (19.4%). PMID:27355937

  7. The Spin Move: A Reliable and Cost-Effective Gowning Technique for the 21st Century

    PubMed Central

    Ochiai, Derek H.; Adib, Farshad

    2015-01-01

    Operating room efficiency (ORE) and utilization are considered one of the most crucial components of quality improvement in every hospital. We introduced a new gowning technique that could optimize ORE. The Spin Move quickly and efficiently wraps a surgical gown around the surgeon's body. This saves the operative time expended through the traditional gowning techniques. In the Spin Move, while the surgeon is approaching the scrub nurse, he or she uses the left heel as the fulcrum. The torque, which is generated by twisting the right leg around the left leg, helps the surgeon to close the gown as quickly and safely as possible. From 2003 to 2012, the Spin Move was performed in 1,725 consecutive procedures with no complication. The estimated average time was 5.3 and 7.8 seconds for the Spin Move and traditional gowning, respectively. The estimated time saving for the senior author during this period was 71.875 minutes. Approximately 20,000 orthopaedic surgeons practice in the United States. If this technique had been used, 23,958 hours could have been saved. The money saving could have been $14,374,800.00 (23,958 hours × $600/operating room hour) during the past 10 years. The Spin Move is easy to perform and reproducible. It saves operating room time and increases ORE. PMID:26052490

  8. A technique for measurement of vector and tensor polarization in solid spin one polarized targets

    SciTech Connect

    Kielhorn, W.F.

    1991-06-01

    Vector and tensor polarizations are explicitly defined and used to characterize the polarization states of spin one polarized targets, and a technique for extracting these polarizations from nuclear magnetic resonance (NMR) data is developed. This technique is independent of assumptions about spin temperature, but assumes the target's crystal structure induces a quadrupole interaction with the spin one particles. Analysis of the NMR signals involves a computer curve fitting algorithm implemented with a fast Fourier transform method which speeds and simplifies curve fitting algorithms used previously. For accurate curve fitting, the NMR electronic circuit must be modeled by the fitting algorithm. Details of a circuit, its model, and data collected from this circuit are given for a solid deuterated ammonia target. 37 refs., 19 figs., 3 tabs.

  9. Understanding Thermodynamic and Spectroscopic Properties of Tetragonal Mn12 Single-Molecule Magnets from Combined Density Functional Theory/Spin-Hamiltonian Calculations.

    PubMed

    Ghassemi Tabrizi, Shadan; Arbuznikov, Alexei V; Kaupp, Martin

    2016-09-01

    We apply broken-symmetry density functional theory to determine isotropic exchange-coupling constants and local zero-field splitting (ZFS) tensors for the tetragonal Mn12(t)BuAc single-molecule magnet. The obtained parametrization of the many-spin Hamiltonian (MSH), taking into account all 12 spin centers, is assessed by comparing theoretical predictions for thermodynamic and spectroscopic properties with available experimental data. The magnetic susceptibility (calculated by the finite-temperature Lanczos method) is well approximated, and the intermultiplet excitation spectrum from inelastic neutron scattering (INS) experiments is correctly reproduced. In these respects, the present parametrization of the 12-spin model represents a significant improvement over previous theoretical estimates of exchange-coupling constants in Mn12, and additionally offers a refined interpretation of INS spectra. Treating anisotropic interactions at the third order of perturbation theory, the MSH is mapped onto the giant-spin Hamiltonian describing the S = 10 ground multiplet. Although the agreement with high-field EPR experiments is not perfect, the results clearly point in the right direction and for the first time rationalize the angular dependence of the transverse-field spectra from a fully microscopic viewpoint. Importantly, transverse anisotropy of the effective S = 10 manifold is explicitly shown to arise largely from the ZFS-induced mixing of exchange multiplets. This effect is given a thorough analysis in the approximate D2d spin-permutational symmetry group of the exchange Hamiltonian. PMID:27482933

  10. Spectroscopic Techniques in the Chemistry Laboratory: A Science Enrichment Course for High School Teachers.

    ERIC Educational Resources Information Center

    Emert, Jack; Zeldin, Martel

    1980-01-01

    Describes a National Science Foundation sponsored enrichment program training high school teachers in modern innovative ideas. Specifically, the course described here was developed to present the uses and applications of spectroscopic methods. (CS)

  11. [Application of Raman spectroscopic technique to the identification and investigation of Chinese ancient jades and jade artifacts].

    PubMed

    Zhao, Hong-Xia; Gan, Fu-Xi

    2009-11-01

    Laser Raman spectroscopic technique is one of the essential methods in scientific archaeological research, which belongs to the nondestructive analysis. As a very good nondestructive analysis approach, it has not been widely applied in the research of the Chinese ancient jade artifacts. First of all in the present paper the fundamentals of laser Raman spectroscopic technique and the new research progress in this field were reviewed. Secondly, the Raman spectra of five familiar jades including nephrite (mainly composed of tremolite), Xiuyan Jade (mainly composed of serpentine), Dushan Jade (mainly composed of anorthite and Zoisite), turquoise and lapis lazuli were summarized respectively. As for an example, the Raman spectra of the four Chinese ancient jade artifacts excavated from Liangzhu Site of Zhejiang Province and Yinxu Site of Anyang in Henan Province were compared with that of the nephrite sample in Hetian of Xinjiang Province. It was shown that the Raman spectroscopic technique is a good nondestructive approach to the identification and investigation of the structures and mineral composition of Chinese ancient jade artifacts. Finally, the limitations and the foreground of this technique were discussed. PMID:20101970

  12. High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

    SciTech Connect

    Wang, Xin

    1996-12-01

    X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of K{alpha} and K{beta} emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS.

  13. Investigation of Very Slowly Tumbling Spin Labels by Nonlinear Spin Response Techniques: Theory and Experiment for Stationary Electron Electron Double Resonance

    PubMed Central

    Smigel, Murray D.; Dalton, Larry R.; Hyde, James S.; Dalton, Lauraine A.

    1974-01-01

    The investigation of very slowly tumbling spin labels by nonlinear electron spin response techniques is discussed. Such techniques permit characterization of rotational processes with correlation times from 10-3 to 10-7 sec even though the linear spin response (ESR) technique is insensitive to motion in this region. Nonlinear techniques fall into two categories: (a) Techniques (referred to as passage techniques) in which the distribution of saturation throughout the spin system is determined both by the applied magnetic field modulation of the resonance condition and by the modulation of the resonance frequency induced by the molecular motion. The time dependence of this distribution produces phase and amplitude changes in the observed signals. (b) Techniques that measure the integral of the distribution function of the time required for saturated spin packets to move between pumped and observed portions of the spectrum [stationary and pulsed electron electron double resonance (ELDOR) techniques]. Quantitative analysis of passage ESR and stationary ELDOR techniques can be accomplished employing a density matrix treatment that explicitly includes the interaction of the spins with applied radiation and modulation fields. The effect of molecular motion inducing a random modulation of the anisotropic spin interactions can be calculated by describing the motion by the diffusion equation appropriate to the motional model assumed. For infinitesimal steps the eigen-functions of the diffusion operator are known analytically, while for random motion of arbitrary step size they are determined by diagonalizing the transition matrix appropriate for the step model used. The present communication reports investigation of the rotational diffusion of the spin label probes 2,2,6,6-tetramethyl-4-piperidinol-1-oxyl and 17β-hydroxy-4′,4′-dimethylspiro-[5α-androstane-3,2′-oxazolidin]-3′-oxyl in sec-butylbenzene. Experimental spectra are compared with computer simulations of

  14. Applications of synchrotron-based spectroscopic techniques in studying nucleic acids and nucleic acid-functionalized nanomaterials

    PubMed Central

    Wu, Peiwen; Yu, Yang; McGhee, Claire E.; Tan, Li Huey

    2014-01-01

    In this review, we summarize recent progresses in the application of synchrotron-based spectroscopic techniques for nucleic acid research that takes advantage of high-flux and high-brilliance electromagnetic radiation from synchrotron sources. The first section of the review focuses on the characterization of the structure and folding processes of nucleic acids using different types of synchrotron-based spectroscopies, such as X-ray absorption spectroscopy, X-ray emission spectroscopy, X-ray photoelectron spectroscopy, synchrotron radiation circular dichroism, X-ray footprinting and small-angle X-ray scattering. In the second section, the characterization of nucleic acid-based nanostructures, nucleic acid-functionalized nanomaterials and nucleic acid-lipid interactions using these spectroscopic techniques is summarized. Insights gained from these studies are described and future directions of this field are also discussed. PMID:25205057

  15. Determination of lipid content of oleaginous microalgal biomass by NMR spectroscopic and GC-MS techniques.

    PubMed

    Sarpal, Amarijt S; Teixeira, Claudia M L L; Silva, Paulo R M; Lima, Gustavo M; Silva, Samantha R; Monteiro, Thays V; Cunha, Valnei S; Daroda, Romeu J

    2015-05-01

    Direct methods based on (1)H NMR spectroscopic techniques have been developed for the determination of neutral lipids (triglycerides and free fatty acids) and polar lipids (glyceroglycolipids/phospholipids) in the solvent extracts of oleaginous microalgal biomasses cultivated on a laboratory scale with two species in different media. The chemical shift assignments observed in the (1)H and (13)C NMR spectra corresponding to unsaturated (C18:N, N = 1-3, C20:3, C20:5, C22:6, epoxy) and saturated (C14-C18) fatty acid ester components in a complex matrix involving overlapped resonances have been unambiguously confirmed by the application of 2D NMR spectroscopy (total correlation spectroscopy and heteronuclear single quantum coherence-total correlation spectroscopy). The study of the effect of a polar lipid matrix on the determination of neutral lipids by an internal reference blending process by a systematic designed experimental protocol has provided absolute quantification. The fatty acid composition of algal extracts was found to be similar to that of vegetable oils containing saturated (C16-C18:0) and unsaturated (C18:N, N = 1-3, C20:N, N = 3-4, C22:6) fatty acids as confirmed by NMR spectroscopy and gas chromatography-mass spectrometry analyses. The NMR methods developed offer great potential for rapid screening of algal strains for generation of algal biomass with the desired lipid content, quality, and potential for biodiesel and value-added polyunsaturated fatty acids in view of the cost economics of the overall cost of generation of the biomass. PMID:25801382

  16. Control-system techniques for improved departure/spin resistance for fighter aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, L. T.; Gilbert, W. P.; Ogburn, M. E.

    1980-01-01

    Some fundamental information on control system effects on controllability of highly maneuverable aircraft at high angles of attack are summarized as well as techniques for enhancing fighter aircraft departure/spin resistance using control system design. The discussion includes: (1) a brief review of pertinent high angle of attack phenomena including aerodynamics, inertia coupling, and kinematic coupling; (2) effects of conventional stability augmentation systems at high angles of attack; (3) high angle of attack control system concepts designed to enhance departure/spin resistance; and (4) the outlook for applications of these concepts to future fighters, particularly those designs which incorporate relaxed static stability.

  17. Analysis of state-of-the-art single-thruster attitude control techniques for spinning penetrator

    NASA Astrophysics Data System (ADS)

    Raus, Robin; Gao, Yang; Wu, Yunhua; Watt, Mark

    2012-07-01

    The attitude dynamics and manoeuvre survey in this paper is performed for a mission scenario involving a penetrator-type spacecraft: an axisymmetric prolate spacecraft spinning around its minor axis of inertia performing a 90° spin axis reorientation manoeuvre. In contrast to most existing spacecraft only one attitude control thruster is available, providing a control torque perpendicular to the spin axis. Having only one attitude thruster on a spinning spacecraft could be preferred for spacecraft simplicity (lower mass, lower power consumption etc.), or it could be imposed in the context of redundancy/contingency operations. This constraint does yield restrictions on the thruster timings, depending on the ratio of minor to major moments of inertia among other parameters. The Japanese Lunar-A penetrator spacecraft proposal is a good example of such a single-thruster spin-stabilised prolate spacecraft. The attitude dynamics of a spinning rigid body are first investigated analytically, then expanded for the specific case of a prolate and axisymmetric rigid body and finally a cursory exploration of non-rigid body dynamics is made. Next two well-known techniques for manoeuvring a spin-stabilised spacecraft, the Half-cone/Multiple Half-cone and the Rhumb line slew, are compared with two new techniques, the Sector-Arc Slew developed by Astrium Satellites and the Dual-cone developed at Surrey Space Centre. Each technique is introduced and characterised by means of simulation results and illustrations based on the penetrator mission scenario and a brief robustness analysis is performed against errors in moments of inertia and spin rate. Also, the relative benefits of each slew algorithm are discussed in terms of slew accuracy, energy (propellant) efficiency and time efficiency. For example, a sequence of half-cone manoeuvres (a Multi-half-cone manoeuvre) tends to be more energy-efficient than one half-cone for the same final slew angle, but more time-consuming. As another

  18. Electron spin echo envelope modulation studies of the Cu(II)-substituted derivative of isopenicillin N synthase: A structural and spectroscopic model

    SciTech Connect

    Feng Jiang; Peisach, J. ); Lijune Ming; Que, L. Jr. ); Chen, V.J. )

    1991-12-03

    Electron spin echo envelope modulation spectroscopy (ESEEM) was used to study the active site structure of isopenicillin N synthase (IPNS) from Cephalosporium acremonium with Cu(II) as a spectroscopic probe. Fourier transform of the simulated electron spin-echo envelope for the Cu(II)-substituted enzyme, Cu(II)IPNS, revealed two nearly magnetically equivalent, equatorially coordinated His imidazoles. The superhyperfine coupling constant, A{sub iso}, for the remote {sup 14}N of each imidazole was 1.65 MHz. The binding of substrate to the enzyme altered the magnetic coupling so that A{sub iso} is 1.30 MHz for one nitrogen and 2.16 MHz for the other. From a comparison of the ESSEM of Cu(II)IPNS in D{sub 2}O and H{sub 2}O, it is suggested that water is a ligand of Cu(II) and this is displaced upon the addition of substrate.

  19. New technique for single-scan T1 measurements using solid echoes. [for spin-lattice relaxation time

    NASA Technical Reports Server (NTRS)

    Burum, D. P.; Elleman, D. D.; Rhim, W. K.

    1978-01-01

    A simple technique for single-scan T1 measurements in solids is proposed and analyzed for single exponential spin-lattice relaxation. In this technique, the direct spin heating caused by the sampling process is significantly reduced in comparison with conventional techniques by utilizing the 'solid echo' to refocus the magnetization. The applicability of this technique to both the solid and liquid phases is demonstrated.

  20. Electron spin-echo techniques for the study of protein motion

    NASA Astrophysics Data System (ADS)

    Kar, Leela; Johnson, Michael E.; Bowman, Michael K.

    Electron spin-echo (ESE) spectroscopy has been used to make the first direct measurements of spin-spin relaxation times of a spin-labeled protein at physiological temperatures. Results from experiments using maleimide-labeled deoxygenated hemoglobin (dHb) from individuals homozygous for sickle cell anemia (dHbS) have been compared with those from control experiments using dHb from normal adults (dHbA). Hb "immobilized" by ammonium sulfate precipitation and by siloxane polymer entrapment have been studied for a suitable "rigid" reference. Two-dimensional ESE (2D-ESE) experiments have been performed using all of these systems. The 2D contour plots show that 2D-ESE is sensitive to the slow motion of dHbS polymers and can differentiate it from both that of immobilized Hb and of HbA molecules in solution at the same temperature and concentration. More importantly, the 2D-ESE technique enables one to select for slower motion and thereby extract the dHbS polymer signal from the total signal generated by the heterogeneous system containing dHbS molecules in solution as well as in the polymer. Computer simulations using current slow motional theories show that detailed motional and structural information may be obtained by such studies. The considerable potential of 2D-ESE spectroscopy in the study of macromolecular motion is illustrated by comparing 2D-ESE with the nonlinear technique of saturation transfer electron paramagnetic resonance.

  1. Accurate calculations on the 12 electronic states and 23 Ω states of the SiBr+ cation: potential energy curves, spectroscopic parameters and spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Shi, De-Heng; Liu, Qionglan; Yu, Wei; Sun, Jinfeng; Zhu, Zunlue

    2014-05-01

    The potential energy curves (PECs) of 23 Ω states generated from the 12 electronic states (X1 Σ +, 21 Σ +, 11 Σ -, 11 Π, 21 Π, 11 Δ, 13 Σ +, 23 Σ +, 13 Σ -, a3 Π, 23 Π and 13 Δ) are studied for the first time. All the states correlate to the first dissociation channel of the SiBr+ cation. Of these electronic states, the 23 Σ + is the repulsive one without the spin-orbit coupling, whereas it becomes the bound one with the spin-orbit coupling added. On the one hand, without the spin-orbit coupling, the 11 Π, 21 Π and 23 Π are the rather weakly bound states, and only the 11 Π state possesses the double well; on the other hand, with the spin-orbit coupling included, the a3 Π and 11 Π states possess the double well, and the 13 Σ + and 13 Σ - are the inverted states. The PECs are calculated by the CASSCF method, which is followed by the internally contracted MRCI approach with the Davidson modification. Scalar relativistic correction is calculated by the third-order Douglas-Kroll Hamiltonian approximation with a cc-pVTZ-DK basis set. Core-valence correlation correction is included with a cc-pCVTZ basis set. The spin-orbit coupling is accounted for by the state interaction method with the Breit-Pauli Hamiltonian using the all-electron aug-cc-pCVTZ basis set. All the PECs are extrapolated to the complete basis set limit. The variation with internuclear separation of the spin-orbit coupling constant is discussed in brief. The spectroscopic parameters are evaluated for the 11 bound electronic states and the 23 bound Ω states, and are compared with available measurements. Excellent agreement has been found between the present results and the experimental data. It demonstrates that the spectroscopic parameters reported here can be expected to be reliably predicted ones. The Franck-Condon factors and radiative lifetimes of the transitions from the a3 Π 0 + and a3 Π 1 states to the X1 Σ + 0+ state are calculated for several low vibrational levels, and

  2. Microwave band on-chip coil technique for single electron spin resonance in a quantum dot.

    PubMed

    Obata, Toshiaki; Pioro-Ladrière, Michel; Kubo, Toshihiro; Yoshida, Katsuharu; Tokura, Yasuhiro; Tarucha, Seigo

    2007-10-01

    Microwave band on-chip microcoils are developed for the application to single electron spin resonance measurement with a single quantum dot. Basic properties such as characteristic impedance and electromagnetic field distribution are examined for various coil designs by means of experiment and simulation. The combined setup operates relevantly in the experiment at dilution temperature. The frequency responses of the return loss and Coulomb blockade current are examined. Capacitive coupling between a coil and a quantum dot causes photon assisted tunneling, whose signal can greatly overlap the electron spin resonance signal. To suppress the photon assisted tunneling effect, a technique for compensating for the microwave electric field is developed. Good performance of this technique is confirmed from measurement of Coulomb blockade oscillations. PMID:17979446

  3. Accurate spectroscopic calculations of the 17 Λ-S and 59 Ω states of the AsP molecule including the spin-orbit coupling effect

    NASA Astrophysics Data System (ADS)

    Shi, Deheng; Liu, Qionglan; Wang, Shuai; Sun, Jinfeng; Zhu, Zunlue

    2015-01-01

    The potential energy curves (PECs) of 59 Ω states generated from the 17 Λ-S states (X1Σ+, a3Σ+, 15Σ+, b3Δ, c3Π, 15Π, 25Σ+, 23Δ, 23Π, 33Σ+, A1Π, 23Σ+, 35Σ+, 17Σ+, 15Δ, 25Δ, and 25Π) of AsP molecule are studied for the first time for internuclear separations from about 0.10 to 1.10 nm. All the Λ-S states are contributed to the first three dissociation channels of AsP molecule except for the A1Π. The 23Σ+, 35Σ+, 17Σ+, 15Δ, 25Δ, and 25Π are found to be the repulsive states. The a3Σ+, 15Π, b3Δ, 17Σ+, 15Δ, 25Δ, and 25Π are found to be the inverted states. Each of the 33Σ+, c3Π, 23Π, 15Π, and 15Σ+ states has one potential barrier. The PECs are calculated by the CASSCF method, which is followed by the internally contracted MRCI approach with Davidson correction. Core-valence correlation and scalar relativistic corrections are included. The convergent behavior of present calculations is discussed with respect to the basis set and level of theory. The spin-orbit coupling effect is accounted for. All these PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated for the bound states involved, and are compared with available measurements. Excellent agreement has been found between the present results and the measurements. It shows that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones. The conclusion is gained that the effect of spin-orbit coupling on the spectroscopic parameters is not obvious for all the Λ-S bound states except for few ones such as 15Σ+ and c3Π.

  4. Accurate calculations of spectroscopic properties for the 13 Λ-S states and the 23 Ω states of BO radical including the spin-orbit coupling effect.

    PubMed

    Zhu, Zunlue; Yu, Wei; Wang, Shuai; Sun, Jinfeng; Shi, Deheng

    2014-10-15

    The spectroscopic properties of 23 Ω states generated from the 13 Λ-S states of BO radical are studied for the first time for internuclear separations from about 0.07 to 1.0nm. Of the 13 Λ-S states, each of the F(2)Π, 1(2)Φ and 1(2)Δ states is found to possess the double well. Each of the 1(4)Π, C(2)Π, 1(2)Σ(-) and 2(2)Σ(-) states possesses one well with one barrier. The A(2)Π, 1(4)Π and F(2)Π are the inverted states with the spin-orbit coupling effect taken into account. All the states possess the deep well except for the 1(2)Φ. The potential energy curves (PECs) are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. Core-valence correlation and scalar relativistic corrections are included into the calculations. The PECs are extrapolated to the complete basis set limit. The spin-orbit coupling effect is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. The spectroscopic parameters are evaluated, and compared with the available measurements and other theoretical results. The Franck-Condon factors and radiative lifetimes of the transitions from the B(2)Σ(+), C(2)Π, D(2)Σ(+), 1(2)Σ(-) and 1(4)Π Λ-S states to the ground state are calculated for several low vibrational levels, and some necessary discussion is made. Analyses show that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones. PMID:24820321

  5. Radio-controlled model design and testing techniques for stall/spin evaluation of general-aviation aircraft

    NASA Technical Reports Server (NTRS)

    Burk, S. M., Jr.; Wilson, C. F., Jr.

    1975-01-01

    A relatively inexpensive radio-controlled model stall/spin test technique was developed. Operational experiences using the technique are presented. A discussion of model construction techniques, spin-recovery parachute system, data recording system, and movie camera tracking system is included. Also discussed are a method of measuring moments of inertia, scaling of engine thrust, cost and time required to conduct a program, and examples of the results obtained from the flight tests.

  6. EPR techniques to probe insertion and conformation of spin-labeled proteins in lipid bilayers.

    PubMed

    Bordignon, Enrica; Polyhach, Yevhen

    2013-01-01

    Electron paramagnetic resonance (EPR) spectroscopy of spin-labeled membrane proteins is a valuable biophysical technique to study structural details and conformational transitions of proteins close to their physiological environment, e.g., in liposomes, membrane bilayers, and nanodiscs. Unlike in nuclear magnetic resonance spectroscopy, having only one or few specific side chains labeled at a time with paramagnetic probes makes the size of the object under investigation irrelevant in terms of technique sensitivity. As a drawback, extensive site-directed mutagenesis is required in order to analyze the properties of the protein under investigation. EPR can provide detailed information on side chain dynamics of large membrane proteins or protein complexes embedded in membranes with an exquisite sensitivity for flexible regions and on water accessibility profiles across the membrane bilayer. Moreover, distances between the two spin-labeled side chains in membrane proteins can be detected with high precision in the 1.5-6 nm range at cryogenic temperatures. The application of EPR to membrane proteins still presents some challenges in terms of sample preparation, sensitivity, and data interpretation; thus no ready-to-go methodological recipes can be given. However this chapter describes the state of the art in the application of nitroxide-based site-directed spin labeling EPR to membrane proteins, with specific focus on the different types of information which can be obtained with continuous wave and pulsed techniques and on the challenges in sample preparation and data analysis for functional and structural membrane protein studies. PMID:23404283

  7. Explicit demonstration of spinor character for a spin-1/2 nucleus via NMR interferometry

    NASA Technical Reports Server (NTRS)

    Stoll, M. E.; Vaughan, R. W.; Vega, A. J.

    1977-01-01

    The results of a nuclear-magnetic-resonance experiment are presented which directly demonstrate the spinor character of a spin-1/2 nucleus, C-13. The interferometric spectroscopic technique used and its potential applications are discussed.

  8. Coupling spectroscopic and chromatographic techniques for evaluation of the depositional history of hydrocarbons in a subtropical estuary.

    PubMed

    Martins, César C; Doumer, Marta E; Gallice, Wellington C; Dauner, Ana Lúcia L; Cabral, Ana Caroline; Cardoso, Fernanda D; Dolci, Natiely N; Camargo, Luana M; Ferreira, Paulo A L; Figueira, Rubens C L; Mangrich, Antonio S

    2015-10-01

    Spectroscopic and chromatographic techniques can be used together to evaluate hydrocarbon inputs to coastal environments such as the Paranaguá estuarine system (PES), located in the SW Atlantic, Brazil. Historical inputs of aliphatic hydrocarbons (AHs) and polycyclic aromatic hydrocarbons (PAHs) were analyzed using two sediment cores from the PES. The AHs were related to the presence of biogenic organic matter and degraded oil residues. The PAHs were associated with mixed sources. The highest hydrocarbon concentrations were related to oil spills, while relatively low levels could be attributed to the decrease in oil usage during the global oil crisis. The results of electron paramagnetic resonance were in agreement with the absolute AHs and PAHs concentrations measured by chromatographic techniques, while near-infrared spectroscopy results were consistent with unresolved complex mixture (UCM)/total n-alkanes ratios. These findings suggest that the use of a combination of techniques can increase the accuracy of assessment of contamination in sediments. PMID:26210796

  9. Development and Quantification of UV-Visible and Laser Spectroscopic Techniques for Materials Accountability and Process Control

    SciTech Connect

    Ken Czerwinski; Phil Weck; Frederic Poineau

    2010-12-29

    Ultraviolet-Visible Spectroscopy (UV-Visible) and Time Resolved Laser Fluorescence Spectroscopy (TRLFS) optical techniques can permit on-line, real-time analysis of the actinide elements in a solvent extraction process. UV-Visible and TRLFS techniques have been used for measuring the speciation and concentration of the actinides under laboratory conditions. These methods are easily adaptable to multiple sampling geometries, such as dip probes, fiber-optic sample cells, and flow-through cell geometries. To fully exploit these techniques for GNEP applications, the fundamental speciation of the target actinides and the resulting influence on 3 spectroscopic properties must be determined. Through this effort detection limits, process conditions, and speciation of key actinide components can be establish and utilized in a range of areas of interest to GNEP, especially in areas related to materials accountability and process control.

  10. Laser-spectroscopic measurement techniques for hypersonic, turbulent wind tunnel flows

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.; Fletcher, Douglas G.

    1992-01-01

    A review is given of the nature, present status, and capabilities of two laser spectroscopic methods for the simultaneous measurement of temperature, density, and their fluctuations owing to turbulence in high speed wind tunnel flows. One method is based on the two frequency excitation of nitric oxide seeded into a nitrogen flow, using tunable dye lasers. The second, more recent method relies on the excitation of oxygen in air flows using a tunable, ArF excimer laser. Signal are obtained from both the laser induced fluorescence and from Raman scattering of the same laser pulse. Measurements are demonstrated in the turbulent boundary layer of a Mach-2 channel flow.

  11. Transition metal quinone-thiosemicarbazone complexes 3: Spectroscopic characterizations of spin-mixed iron (III) of naphthoquinone-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Chikate, Rajeev C.; Padhye, Subhash B.

    2007-04-01

    An interesting series of iron (III) complexes with naphthoquinone-thiosemicarbazones are synthesized and physico-chemically characterized by elemental analysis, UV-vis, IR, EPR and magnetic susceptibility measurements. They possess a cationic octahedral [FeL 2] + species and a tetrahedral [FeCl 4] - anion and exhibit unusual spin-mixed states involving high-spin and low-spin ferric centers as revealed from magnetic behavior with significant amount of exchange interactions mediated by intermolecular associations. The magnetic susceptibility data is fitted with S=5/2 and S=1/2 Heisengberg's exchange coupled model; Hˆ=-2JSS and the magnetic exchange interactions are found to be of the order of -13.6 cm -1 indicating the moderate coupling between two paramagnetic centers present in different chemical and structural environment. The presence of spin-paired iron (III) cation having dxz2dxz2dxz1 ground state is revealed from the EPR spectra with three prominent peaks while the high-spin tetrahedral iron (III) anion exhibits characteristics g = 4 signal whose intensity increases with lowering the temperature suggesting its influence on the magnetic properties of the complex molecule. FTIR measurements indicate tridentate ONS donor systems involving quinone/hydroxyl oxygen, imine/hydrazinic nitrogen and thione/thiol sulfur atoms as binding sites for naphthoquinone-thiosemicarbazones.

  12. Variable flip angle imaging and fat suppression in combined gradient and spin-echo (GREASE) techniques

    SciTech Connect

    Vinitski, S.; Mitchell, D.G.; Szumowski, J.; Burk, D.L. Jr.; Rifkin, M.D. )

    1990-01-01

    Conventional proton density and T2-weighted spin-echo images are susceptible to motion induced artifact, which is exacerbated by lipid signals. Gradient moment nulling can reduce motion artifact but lengthens the minimum TE, degrading the proton density contrast. We designed a pulse sequence capable of optimizing proton density and T2-weighted contrast while suppressing lipid signals and motion induced artifacts. Proton density weighting was obtained by rapid readout gradient reversal immediately after the excitation RF pulse, within a conventional spin-echo sequence. By analyzing the behavior of the macroscopic magnetization and optimizing excitation flip angle, we suppressed T1 contribution to the image, thereby enhancing proton density and T2-weighted contrast with a two- to four-fold reduction of repetition time. This permitted an increased number of averages to be used, reducing motion induced artifacts. Fat suppression in the presence of motion was investigated in two groups of 8 volunteers each by (i) modified Dixon technique, (ii) selective excitation, and (iii) hybrid of both. Elimination of fat signal by the first technique was relatively uniform across the field of view, but it did not fully suppress the ghosts originating from fat motion. Selective excitation, while sensitive to the main field inhomogeneity, largely eliminated the ghosts (0.21 +/- 0.05 vs. 0.29 +/- 0.06, p less than 0.01). The hybrid of both techniques combined with bandwidth optimization, however, showed the best results (0.17 +/- 0.04, p less than 0.001). Variable flip-angle imaging allows optimization of image contrast which, along with averaging and effective fat suppression, significantly improves gradient- and spin-echo imaging, particularly in the presence of motion.

  13. Rapid determination of internal volumes of membrane vesicles with electron spin resonance-stopped flow technique.

    PubMed

    Anzai, K; Higashi, K; Kirino, Y

    1988-01-13

    We have developed an electron spin resonance (ESR)-stopped flow technique and employed it for the simple and rapid determination of internal volumes of biomembrane vesicles and liposomes. A vesicle suspension containing a neutral and membrane-permeable spin label, 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (TEMPONE), was mixed in the stopped-flow apparatus with an isotonic solution of relatively impermeable line broadening agents, potassium tris(oxalato)chromate(III) or potassium ferricyanide, and an ESR spectrum was recorded. From the relative intensity of the sharp triplet signal due to TEMPONE in the aqueous space within vesicles, the determination of the internal aqueous volume was straightforward. Using this technique, it is possible to measure intravesicular volumes in 0.1 s. The internal volume of sonicated phospholipid vesicles was approximately 0.3 microliter/mg lipid. The light fraction of sarcoplasmic reticulum membrane vesicles isolated from rabbit skeletal muscle was estimated to have an internal volume of 2.2-2.6 microliter/mg protein in its resting state. Activation of Ca2+ pumps in the membrane upon addition of ATP and Ca2+ ions decreased the internal volume by about 10%. This finding supports the hypothesis that the Ca2+ pump is electrogenic and that the efflux of potassium ions compensates for the influx of positive charges. The present technique is widely applicable to the simple and rapid determination of the internal volumes of membrane vesicles. PMID:2825810

  14. Effect of salt on the structure of middle phase microemulsions using the spin-label technique

    SciTech Connect

    Ramachandran, C.; Vijayan, S.; Shah, D.O.

    1980-06-12

    The middle phases obtained by varying the sodium chloride concentration in surfactant formulations containing 5:3 (wt/wt) TRS 10-410 (a petroleum sulfonate)-isobutyl alcohol and equal volumes of aqueous and oil phases were studied by using spin-labeling techniques. Two different spin-labels, one partially water soluble (5-doxylstearic acid label) and the other water insoluble (3-doxylcholestane label), were used. Extensive measurements of electrical conductivity and phase volumes of the middle phases were also carried out. These physical property results corroborated the spin-label studies in that below 2.0 wt % NaCl the middle phase was essentially a microemulsion of the water external type. Beyond 2.3% NaCl the appearance of a signal component typical of a free label (ketostearic acid) in an oil environment and changes in correlation time characteristics (cholestane label) coupled with physical property data underlined a qualitative change in the microemulsion system. It is believed that these changes are consistent with a transition from a water-external type to an oil-external type microemulsion system. This transition is estimated to be around 2 to 2.3% NaCl. The results are further substantiated by ascorbic acid reduction rate studies. Possible mechanisms of this transition are discussed.

  15. New Spectroscopic Technique Based on Coaddition of Surface Brightness Fluctuations: NGC 4449 and its Stellar Tidal Stream

    NASA Astrophysics Data System (ADS)

    Toloba, Elisa; Guhathakurta, Puragra; Romanowsky, Aaron J.; Brodie, Jean P.; Martínez-Delgado, David; Arnold, Jacob A.; Ramachandran, Neel; Theakanath, Kuriakose

    2016-06-01

    We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities of galaxies of low surface brightness effects both to galaxies and streams beyond the Local Group. The distance to these systems makes them unsuitable for targeting individual red giant branch (RGB) stars (tip of RGB at I≳ 24 mag) and their surface brightness is too low ({μ }r≳ 25 mag arcsec‑2) for integrated light spectroscopic measurements. This technique overcomes these two problems by targeting individual objects that are brighter than the tip of the RGB. We apply this technique to the star-forming dwarf galaxy NGC 4449 and its stellar stream. We use Keck/DEIMOS data to measure the line-of-sight radial velocity out to ∼7 kpc in the east side of the galaxy and ∼8 kpc along the stream. We find that the two systems are likely gravitationally bound to each other and have heliocentric radial velocities of 227.3 ± 10.7 km s‑1 and 225.8 ± 16.0 km s‑1, respectively. Neither the stream nor the near half of the galaxy shows a significant velocity gradient. We estimate the stellar metallicity of the stream based on the equivalent width of its calcium triplet lines and find [Fe/H] =\\quad -1.37+/- 0.41, which is consistent with the metallicity–luminosity relation for dwarf galaxies in the Local Group. Whether the stream's progenitor was moderately or severely stripped cannot be constrained with this uncertainty in metallicity. We demonstrate that this new technique can be used to measure the kinematics and (possibly) the metallicity of the numerous faint satellites and stellar streams in the halos of nearby (∼4 Mpc) galaxies.

  16. New Spectroscopic Technique Based on Coaddition of Surface Brightness Fluctuations: NGC 4449 and its Stellar Tidal Stream

    NASA Astrophysics Data System (ADS)

    Toloba, Elisa; Guhathakurta, Puragra; Romanowsky, Aaron J.; Brodie, Jean P.; Martínez-Delgado, David; Arnold, Jacob A.; Ramachandran, Neel; Theakanath, Kuriakose

    2016-06-01

    We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities of galaxies of low surface brightness effects both to galaxies and streams beyond the Local Group. The distance to these systems makes them unsuitable for targeting individual red giant branch (RGB) stars (tip of RGB at I≳ 24 mag) and their surface brightness is too low ({μ }r≳ 25 mag arcsec‑2) for integrated light spectroscopic measurements. This technique overcomes these two problems by targeting individual objects that are brighter than the tip of the RGB. We apply this technique to the star-forming dwarf galaxy NGC 4449 and its stellar stream. We use Keck/DEIMOS data to measure the line-of-sight radial velocity out to ˜7 kpc in the east side of the galaxy and ˜8 kpc along the stream. We find that the two systems are likely gravitationally bound to each other and have heliocentric radial velocities of 227.3 ± 10.7 km s‑1 and 225.8 ± 16.0 km s‑1, respectively. Neither the stream nor the near half of the galaxy shows a significant velocity gradient. We estimate the stellar metallicity of the stream based on the equivalent width of its calcium triplet lines and find [Fe/H] =\\quad -1.37+/- 0.41, which is consistent with the metallicity–luminosity relation for dwarf galaxies in the Local Group. Whether the stream's progenitor was moderately or severely stripped cannot be constrained with this uncertainty in metallicity. We demonstrate that this new technique can be used to measure the kinematics and (possibly) the metallicity of the numerous faint satellites and stellar streams in the halos of nearby (˜4 Mpc) galaxies.

  17. Pressure Induced Amorphization in Garnets investigated by X-ray Diffraction and Spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Hua, Hong; Vohra, Yogesh K.

    1996-03-01

    We report the first direct observation of pressure induced amorphization in garnets GGG and GSGG at ambient temperature(both are Cr^3+, Nd^3+ doped). Laser spectroscopic studies show abrupt disappearance of fluorescent emission peaks at high pressure due to loss of the long range order. The amorphization was confirmed by the synchrotron x-ray diffraction studies at X-17C, NSLS. The amorphization pressure for GSGG is 58±3GPa and for GGG is 90±5GPa. The transformation pressures for the garnets are correlated to the strength of the crystal field. The amorphous phase can be quenched at ambient conditions. The amorphization phenomenon in garnets is explained on the basis of a three-level thermodynamic model. (Supported by NSF Grant No. DMR-9403832)

  18. Ultrawide band multifrequency high-field EMR technique: A methodology for increasing spectroscopic information.

    PubMed

    Hassan, A K; Pardi, L A; Krzystek, J; Sienkiewicz, A; Goy, P; Rohrer, M; Brunel, L C

    2000-02-01

    We report methodology that combines an ultrawide band multifrequency microwave system with technology of high magnetic fields for solving challenging problems in electron magnetic resonance (EMR) spectroscopy. This strategy has been made possible due to a novel EMR facility operating in an exceptionally wide range of microwave frequencies of 24 GHz to 3 THz, at magnetic fields up to 17 T, and in the temperature range of 1.6 to 330 K. The basic configuration of the multifrequency system works in a transmission mode and employs oversized cylindrical waveguides for routing the microwave power. A wide-band, low-noise, liquid helium cooled (4.2 K) InSb bolometer is used for signal detection. This approach results in an extremely wide-band performance, thus making it possible to employ a variety of solid-state millimeter and submillimeter microwave sources in combination with a far infrared laser microwave source for performing multifrequency EMR experiments. A complexity of resonant structures and related technical problems such as microphonics at high magnetic fields is virtually eliminated. The system is simple, yet sensitive, and has been revealed to be extremely advantageous while solving such problems as observation of AFMR transitions in spin-ordered systems, g-factor resolution enhancement in complex organic radicals, and resonance signal detection in EMR-silent spin systems having integer spin and large zero field splitting. A technical description of the multifrequency high-field EMR facility is presented and results of its performance tests are given. The potential utility of using the multifrequency high-field methodology in EMR studies is illustrated with selected examples of its recent applications. PMID:10648147

  19. Spectroscopy of composite solid-state spin environments for improved metrology with spin ensembles

    NASA Astrophysics Data System (ADS)

    Bar-Gill, Nir; Pham, Linh; Belthangady, Chinmay; Lesage, David; Cappellaro, Paola; Maze, Jeronimo; Lukin, Mikhail; Yacoby, Amir; Walsworth, Ronald

    2012-02-01

    For precision coherent measurements with ensembles of quantum spins the relevant Figure-of-Merit (FOM) is the product of spin density and coherence lifetime, which is generally limited by the dynamics of spin coupling to the environment. Significant effort has been invested in understanding the causes of decoherence in a diverse range of spin systems in order to increase the FOM and improve measurement sensitivity. Here, we apply a coherent spectroscopic technique to characterize the dynamics of a composite solid-state spin environment consisting of Nitrogen-Vacancy (NV) color centers in room temperature diamond coupled to baths of electronic spin (N) and nuclear spin (13C) impurities. For diamond samples with a wide range of NV densities and impurity spin concentrations we employ a dynamical decoupling technique to minimize coupling to the environment, and find similar values for the FOM, which is three orders of magnitude larger than previously achieved in any room-temperature solid-state spin system, and thus should enable greatly improved precision spin metrology. We also identify a suppression of electronic spin bath dynamics in the presence of a nuclear spin bath of sufficient nuclear spin concentration. This suppression could inform efforts to engineer samples with even larger FOM for solid-state spin ensemble metrology and collective quantum information processing.

  20. Accurate spectroscopic calculations of the 17 Λ-S and 59 Ω states of the AsP molecule including the spin-orbit coupling effect.

    PubMed

    Shi, Deheng; Liu, Qionglan; Wang, Shuai; Sun, Jinfeng; Zhu, Zunlue

    2015-01-25

    The potential energy curves (PECs) of 59 Ω states generated from the 17 Λ-S states (X(1)Σ(+), a(3)Σ(+), 1(5)Σ(+), b(3)Δ, c(3)Π, 1(5)Π, 2(5)Σ(+), 2(3)Δ, 2(3)Π, 3(3)Σ(+), A(1)Π, 2(3)Σ(+), 3(5)Σ(+), 1(7)Σ(+), 1(5)Δ, 2(5)Δ, and 2(5)Π) of AsP molecule are studied for the first time for internuclear separations from about 0.10 to 1.10nm. All the Λ-S states are contributed to the first three dissociation channels of AsP molecule except for the A(1)Π. The 2(3)Σ(+), 3(5)Σ(+), 1(7)Σ(+), 1(5)Δ, 2(5)Δ, and 2(5)Π are found to be the repulsive states. The a(3)Σ(+), 1(5)Π, b(3)Δ, 1(7)Σ(+), 1(5)Δ, 2(5)Δ, and 2(5)Π are found to be the inverted states. Each of the 3(3)Σ(+), c(3)Π, 2(3)Π, 1(5)Π, and 1(5)Σ(+) states has one potential barrier. The PECs are calculated by the CASSCF method, which is followed by the internally contracted MRCI approach with Davidson correction. Core-valence correlation and scalar relativistic corrections are included. The convergent behavior of present calculations is discussed with respect to the basis set and level of theory. The spin-orbit coupling effect is accounted for. All these PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are evaluated for the bound states involved, and are compared with available measurements. Excellent agreement has been found between the present results and the measurements. It shows that the spectroscopic parameters reported in this paper can be expected to be reliably predicted ones. The conclusion is gained that the effect of spin-orbit coupling on the spectroscopic parameters is not obvious for all the Λ-S bound states except for few ones such as 1(5)Σ(+) and c(3)Π. PMID:25145917

  1. Accurate calculations on 12 Λ-S and 28 Ω states of BN+ cation: potential energy curves, spectroscopic parameters and spin-orbit coupling.

    PubMed

    Shi, Deheng; Liu, Qionglan; Sun, Jinfeng; Zhu, Zunlue

    2014-03-25

    The potential energy curves (PECs) of 28 Ω states generated from the 12 states (X(4)Σ(-), 1(2)Π, 1(2)Σ(-), 1(2)Δ, 1(2)Σ(+), 2(2)Π, A(4)Π, B(4)Σ(-), 3(2)Π, 1(6)Σ(-), 2(2)Σ(-) and 1(6)Π) of the BN(+) cation are studied for the first time for internuclear separations from about 0.1 to 1.0 nm using an ab initio quantum chemical method. All the Λ-S states correlate to the first four dissociation channels. The 1(6)Σ(-), 3(2)Π and A(4)Π states are found to be the inverted ones. The 1(2)Σ(+), 2(2)Π, 3(2)Π and 2(2)Σ(-) states are found to possess the double well. The PECs are calculated by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson correction. Core-valence correlation correction is included by a cc-pCV5Z basis set. Scalar relativistic correction is calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. The convergent behavior of present calculations is discussed with respect to the basis set and level of theory. The spin-orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian using the all-electron cc-pCV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The spectroscopic parameters are obtained, and the vibrational properties of 1(2)Σ(+), 2(2)Π, 3(2)Π and 2(2)Σ(-) states are evaluated. Analyses demonstrate that the spectroscopic parameters reported here can be expected to be reliably predicted ones. The conclusion is gained that the effect of spin-orbit coupling on the spectroscopic parameters are not obvious almost for all the Λ-S states involved in the present paper. PMID:24334021

  2. Accurate calculations on 9 Λ-S and 28 Ω states of NSe radical in the gas phase: potential energy curves, spectroscopic parameters and spin-orbit couplings.

    PubMed

    Shi, Deheng; Li, Peiling; Sun, Jinfeng; Zhu, Zunlue

    2014-01-01

    The potential energy curves (PECs) of 28 Ω states generated from 9 Λ-S states (X(2)Π, 1(4)Π, 1(6)Π, 1(2)Σ(+), 1(4)Σ(+), 1(6)Σ(+), 1(4)Σ(-), 2(4)Π and 1(4)Δ) are studied for the first time using an ab initio quantum chemical method. All the 9 Λ-S states correlate to the first two dissociation limits, N((4)Su)+Se((3)Pg) and N((4)Su)+Se((3)Dg), of NSe radical. Of these Λ-S states, the 1(6)Σ(+), 1(4)Σ(+), 1(6)Π, 2(4)Π and 1(4)Δ are found to be rather weakly bound states. The 1(2)Σ(+) is found to be unstable and has double wells. And the 1(6)Σ(+), 1(4)Σ(+), 1(4)Π and 1(6)Π are found to be the inverted ones with the SO coupling included. The PEC calculations are made by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification. The spin-orbit coupling is accounted for by the state interaction approach with the Breit-Pauli Hamiltonian. The convergence of the present calculations is discussed with respect to the basis set and the level of theory. Core-valence correlation corrections are included with a cc-pCVTZ basis set. Scalar relativistic corrections are calculated by the third-order Douglas-Kroll Hamiltonian approximation at the level of a cc-pV5Z basis set. All the PECs are extrapolated to the complete basis set limit. The variation with internuclear separation of spin-orbit coupling constants is discussed in brief for some Λ-S states with one shallow well on each PEC. The spectroscopic parameters of 9 Λ-S and 28 Ω states are determined by fitting the first ten vibrational levels whenever available, which are calculated by solving the rovibrational Schrödinger equation with Numerov's method. The splitting energy in the X(2)Π Λ-S state is determined to be about 864.92 cm(-1), which agrees favorably with the measurements of 891.80 cm(-1). Moreover, other spectroscopic parameters of Λ-S and Ω states involved here are

  3. Artificial tektites: an experimental technique for capturing the shapes of spinning drops.

    PubMed

    Baldwin, Kyle A; Butler, Samuel L; Hill, Richard J A

    2015-01-01

    Determining the shapes of a rotating liquid droplet bound by surface tension is an archetypal problem in the study of the equilibrium shapes of a spinning and charged droplet, a problem that unites models of the stability of the atomic nucleus with the shapes of astronomical-scale, gravitationally-bound masses. The shapes of highly deformed droplets and their stability must be calculated numerically. Although the accuracy of such models has increased with the use of progressively more sophisticated computational techniques and increases in computing power, direct experimental verification is still lacking. Here we present an experimental technique for making wax models of these shapes using diamagnetic levitation. The wax models resemble splash-form tektites, glassy stones formed from molten rock ejected from asteroid impacts. Many tektites have elongated or 'dumb-bell' shapes due to their rotation mid-flight before solidification, just as we observe here. Measurements of the dimensions of our wax 'artificial tektites' show good agreement with equilibrium shapes calculated by our numerical model, and with previous models. These wax models provide the first direct experimental validation for numerical models of the equilibrium shapes of spinning droplets, of importance to fundamental physics and also to studies of tektite formation. PMID:25564381

  4. Artificial tektites: an experimental technique for capturing the shapes of spinning drops

    NASA Astrophysics Data System (ADS)

    Baldwin, Kyle A.; Butler, Samuel L.; Hill, Richard J. A.

    2015-01-01

    Determining the shapes of a rotating liquid droplet bound by surface tension is an archetypal problem in the study of the equilibrium shapes of a spinning and charged droplet, a problem that unites models of the stability of the atomic nucleus with the shapes of astronomical-scale, gravitationally-bound masses. The shapes of highly deformed droplets and their stability must be calculated numerically. Although the accuracy of such models has increased with the use of progressively more sophisticated computational techniques and increases in computing power, direct experimental verification is still lacking. Here we present an experimental technique for making wax models of these shapes using diamagnetic levitation. The wax models resemble splash-form tektites, glassy stones formed from molten rock ejected from asteroid impacts. Many tektites have elongated or `dumb-bell' shapes due to their rotation mid-flight before solidification, just as we observe here. Measurements of the dimensions of our wax `artificial tektites' show good agreement with equilibrium shapes calculated by our numerical model, and with previous models. These wax models provide the first direct experimental validation for numerical models of the equilibrium shapes of spinning droplets, of importance to fundamental physics and also to studies of tektite formation.

  5. Artificial tektites: an experimental technique for capturing the shapes of spinning drops

    PubMed Central

    Baldwin, Kyle A.; Butler, Samuel L.; Hill, Richard J. A.

    2015-01-01

    Determining the shapes of a rotating liquid droplet bound by surface tension is an archetypal problem in the study of the equilibrium shapes of a spinning and charged droplet, a problem that unites models of the stability of the atomic nucleus with the shapes of astronomical-scale, gravitationally-bound masses. The shapes of highly deformed droplets and their stability must be calculated numerically. Although the accuracy of such models has increased with the use of progressively more sophisticated computational techniques and increases in computing power, direct experimental verification is still lacking. Here we present an experimental technique for making wax models of these shapes using diamagnetic levitation. The wax models resemble splash-form tektites, glassy stones formed from molten rock ejected from asteroid impacts. Many tektites have elongated or ‘dumb-bell' shapes due to their rotation mid-flight before solidification, just as we observe here. Measurements of the dimensions of our wax ‘artificial tektites' show good agreement with equilibrium shapes calculated by our numerical model, and with previous models. These wax models provide the first direct experimental validation for numerical models of the equilibrium shapes of spinning droplets, of importance to fundamental physics and also to studies of tektite formation. PMID:25564381

  6. Application of a system modification technique to dynamic tuning of a spinning rotor blade

    NASA Technical Reports Server (NTRS)

    Spain, C. V.

    1987-01-01

    An important consideration in the development of modern helicopters is the vibratory response of the main rotor blade. One way to minimize vibration levels is to ensure that natural frequencies of the spinning main rotor blade are well removed from integer multiples of the rotor speed. A technique for dynamically tuning a finite-element model of a rotor blade to accomplish that end is demonstrated. A brief overview is given of the general purpose finite element system known as Engineering Analysis Language (EAL) which was used in this work. A description of the EAL System Modification (SM) processor is then given along with an explanation of special algorithms developed to be used in conjunction with SM. Finally, this technique is demonstrated by dynamically tuning a model of an advanced composite rotor blade.

  7. Potential energy curves, spectroscopic parameters, and spin-orbit coupling: a theoretical study on 24 Λ-S and 54 Ω states of C2(+) cation.

    PubMed

    Shi, Deheng; Niu, Xianghong; Sun, Jinfeng; Zhu, Zunlue

    2013-03-01

    The potential energy curves (PECs) of 24 Λ-S states and 54 Ω states of the C2(+) cation are studied in detail using an ab initio quantum chemical method. All the PEC calculations are made for internuclear separations from 0.09 to 1.11 nm by the complete active space self-consistent field method, which is followed by the internally contracted multireference configuration interaction approach with the Davidson modification (MRCI+Q). All the Λ-S states involved dissociate into the first dissociation limit, C((3)Pg) + C(+)((2)Pu), of C2(+) cation, of which only the 2(2)Σg(-) and 2(4)Σg(-) are repulsive. The spin-orbit (SO) coupling effect is accounted for by the Breit-Pauli Hamiltonian with an aug-cc-pCVTZ basis set. To improve the quality of PECs, core-valence correlation and scalar relativistic corrections are included. Core-valence correlation corrections are taken into account with an aug-cc-pCVTZ basis set. Scalar relativistic correction calculations are done by the third-order Douglas-Kroll Hamiltonian approximation with the cc-pVQZ basis set. All the PECs are extrapolated to the complete basis set limit. The convergence observations of present calculations are made, and the convergent behavior is discussed with respect to the basis set and level of theory. With the PECs obtained by the MRCI+Q/CV+DK+56 calculations, the spectroscopic parameters of 22 Λ-S bound states of C2(+) cation are evaluated by fitting the first ten vibrational levels, which are obtained by solving the rovibrational Schrödinger equation using Numerov's method. In addition, the spectroscopic parameters of 51 Ω bound states generated from these Λ-S bound states are also obtained. The spectroscopic parameters are compared with those reported in the literature. Excellent agreement with available measurements is found. It is expected that the spectroscopic parameters of Λ-S and Ω states reported here are reliable predicted ones. PMID:23391347

  8. Dichromated poly(vinyl alchohol)-xanthene dye systems: holographic characterization and electron spin resonance spectroscopic study

    NASA Astrophysics Data System (ADS)

    Manivannan, Gurusamy; Changkakoti, Rupak; Lessard, Roger A.; Mailhot, Gilles; Bolte, Michel

    1994-01-01

    Dichromated poly(vinyl alcohol)-xanthene dye (DCPVA-XD) systems have been employed as real-time holographic recording materials. In this paper, holographic characterization of dichromated poly(vinyl alcohol) with fluorescein (Fl), eosin Y (EY) and Rose Bengal (RB) is presented. In addition, a systematic ESR spectroscopic investigation was also performed on these systems. The photochemical evolution of Cr(V), Cr(III), polymer radical and dye radical in these systems has been monitored and a comparison is made.

  9. Nonintrusive spectroscopic techniques for supersonic/hypersonic aerodynamics and combustion diagnostics

    NASA Technical Reports Server (NTRS)

    Exton, R. J.

    1992-01-01

    This paper presents an overview of the primary nonintrusive diagnostic techniques being developed by the NASA Langley Research Center to address the validation needs of Computational Fluid Dynamic (CFD) codes. The techniques include absorption in the UV and IR, Laser Induced Fluorescence, electron beam fluorescence, and a number of scattering techniques including Rayleigh, spontaneous Raman, and several coherent Raman spectroscopies. Most of the techniques are highly specialized, require complex data interpretation, and can satisfy only a few of the CFD needs. For these reasons, the evolving trend in flowfield diagnostics appears to favor a mode in which the diagnostic researcher, the experimental aerodynamicist, and the CFD community jointly define experiments based on the aeronautical requirements and on available diagnostic techniques.

  10. Molecular structure and spectroscopic characterization of Carbamazepine with experimental techniques and DFT quantum chemical calculations.

    PubMed

    Suhasini, M; Sailatha, E; Gunasekaran, S; Ramkumaar, G R

    2015-04-15

    A systematic vibrational spectroscopic assignment and analysis of Carbamazepine has been carried out by using FT-IR, FT-Raman and UV spectral data. The vibrational analysis were aided by electronic structure calculations - ab initio (RHF) and hybrid density functional methods (B3LYP) performed with standard basis set 6-31G(d,p). Molecular equilibrium geometries, electronic energies, natural bond order analysis, harmonic vibrational frequencies and IR intensities have been computed. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED) by VEDA program. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λmax were determined by HF/6-311++G(d,p) Time-Dependent method. The thermodynamic functions of the title molecule were also performed using the RHF and DFT methods. The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance (NMR) calculation procedure was also performed, and it was used for assigning the (13)C and (1)H NMR chemical shifts of Carbamazepine. PMID:25682215

  11. Molecular structure and spectroscopic characterization of Carbamazepine with experimental techniques and DFT quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Suhasini, M.; Sailatha, E.; Gunasekaran, S.; Ramkumaar, G. R.

    2015-04-01

    A systematic vibrational spectroscopic assignment and analysis of Carbamazepine has been carried out by using FT-IR, FT-Raman and UV spectral data. The vibrational analysis were aided by electronic structure calculations - ab initio (RHF) and hybrid density functional methods (B3LYP) performed with standard basis set 6-31G(d,p). Molecular equilibrium geometries, electronic energies, natural bond order analysis, harmonic vibrational frequencies and IR intensities have been computed. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED) by VEDA program. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λmax were determined by HF/6-311++G(d,p) Time-Dependent method. The thermodynamic functions of the title molecule were also performed using the RHF and DFT methods. The restricted Hartree-Fock and density functional theory-based nuclear magnetic resonance (NMR) calculation procedure was also performed, and it was used for assigning the 13C and 1H NMR chemical shifts of Carbamazepine.

  12. Structure, spectra and antioxidant action of ascorbic acid studied by density functional theory, Raman spectroscopic and nuclear magnetic resonance techniques

    NASA Astrophysics Data System (ADS)

    Singh, Gurpreet; Mohanty, B. P.; Saini, G. S. S.

    2016-02-01

    Structure, vibrational and nuclear magnetic resonance spectra, and antioxidant action of ascorbic acid towards hydroxyl radicals have been studied computationally and in vitro by ultraviolet-visible, nuclear magnetic resonance and vibrational spectroscopic techniques. Time dependant density functional theory calculations have been employed to specify various electronic transitions in ultraviolet-visible spectra. Observed chemical shifts and vibrational bands in nuclear magnetic resonance and vibrational spectra, respectively have been assigned with the help of calculations. Changes in the structure of ascorbic acid in aqueous phase have been examined computationally and experimentally by recording Raman spectra in aqueous medium. Theoretical calculations of the interaction between ascorbic acid molecule and hydroxyl radical predicted the formation of dehydroascorbic acid as first product, which has been confirmed by comparing its simulated spectra with the corresponding spectra of ascorbic acid in presence of hydrogen peroxide.

  13. Monitoring PDT effects in murine tumors by spectroscopic and imaging techniques

    NASA Astrophysics Data System (ADS)

    Ramaprasad, Subbaraya; Rzepka, Elzbieta; Pi, Jiaxiong; Joshi, Shantaram S.; Dobhal, Mahabeer; Missert, Joseph; Pandey, Ravindra K.

    2004-04-01

    The changes in the tumor that occur following photodynamic therapy (PDT) were studied using a small animal MR imager operating at 7Tesla. The animal model used in these studies was mice bearing radiation induced fibrosarcoma (RIF) tumor on the foot dorsum. The mice were injected with 10μM/kg of one of the photosensitizers: (1) Photofrin, (2) Non-fluorinated porphyrin photosensitizer (DOD-1), (3) Fluorinated porphyrin photosensitizer (DOD-2) and, (4) Fluorinated chlorin photosensitizer (DOD-6). Laser light at 630 or 650 nm (150 mW/cm2, 270 joules/cm2) was delivered to the tumor at 2-24 hours of photosensitizer administration. The MR spectroscopic and imaging examination of the tumors involved both the 1H and 31P nuclei. The tumor bioenergetics was measured by 31P spectroscopy. The water proton relaxivity and diffusion measurements were used to obtain local changes in different regions of the tumor. Changes in 31P MR spectra were observed following PDT using Photofrin and fluorinated chlorin sensitizer (DOD-6). However, no significant changes were observed when the fluorinated porphyrin and its nonfluorinated analog were used. The PDT induced changes in tumor volumes showed significant tumor regression with Photofrin, fluorinated porphyrin and chlorin sensitizers. No tumor regression was observed with the non labeled porphyrin sensitizer and the growth profile followed the general pattern of unperturbed tumors. Serial noninvasive measurements of tumor response to PDT are measurable by both MRI and MRS. The MR derived parameters that are characteristic of the tumor status before and after the therapy are discussed here.

  14. An analytical technique for the analysis of airplane spin entry and recovery

    NASA Technical Reports Server (NTRS)

    Taylor, L. W., Jr.; Miller, G. K., Jr.

    1982-01-01

    The dynamic equations of motion for a spinning airplane are simplified to facilitate the analysis of spin entry and recovery maneuvers. Solutions of a nonlinear, first order equation for spin rate enable calculation of spin entry and recovery times and control required for recovery. The analysis is applied to a light airplane for which both aerodynamic data, rotory balance wind tunnel tests, and spin flight test data have been obtained. A comparison of predicted and actual transient spin responses is made which supports the validity of the analytical approach taken but which also illustrates the difficulty in obtaining accurate aerodynamic data for spinning airplanes. Certain normalized parameters of the reduced state spin equation suggest criteria for assessing the transient spin characteristics of light airplanes.

  15. Technique to determine location of radio sources from measurements taken on spinning spacecraft

    NASA Technical Reports Server (NTRS)

    Fainberg, J.

    1979-01-01

    The procedure developed to extract average source direction and average source size from spin-modulated radio astronomy data measured on the IMP-6 spacecraft is described. Because all measurements are used, rather than just finding maxima or minima in the data, the method is very sensitive, even in the presence of large amounts of noise. The technique is applicable to all experiments with directivity characteristics. It is suitable for onboard processing on satellites to reduce the data flow to Earth. The application to spin-modulated nonpolarized radio astronomy data is made and includes the effects of noise, background, and second source interference. The analysis was tested with computer simulated data and the results agree with analytic predictions. Applications of this method with IMP-6 radio data have led to: (1) determination of source positions of traveling solar radio bursts at large distances from the Sun; (2) mapping of magnetospheric radio emissions by radio triangulation; and (3) detection of low frequency radio emissions from Jupiter and Saturn.

  16. Spectroscopic and Theoretical Study of Spin-Dependent Electron Transfer in an Iron(III) Superoxo Complex.

    PubMed

    Stout, Heather D; Kleespies, Scott T; Chiang, Chien-Wei; Lee, Way-Zen; Que, Lawrence; Münck, Eckard; Bominaar, Emile L

    2016-06-01

    It was shown previously (J. Am. Chem. Soc. 2014, 136, 10846) that bubbling of O2 into a solution of Fe(II)(BDPP) (H2BDPP = 2,6-bis[[(S)-2-(diphenylhydroxymethyl)-1-pyrrolidinyl]methyl]pyridine) in tetrahydrofuran at -80 °C generates a high-spin (SFe = (5)/2) iron(III) superoxo adduct, 1. Mössbauer studies revealed that 1 is an exchange-coupled system, [Formula: see text], where SR = (1)/2 is the spin of the superoxo radical, of which the spectra were not well enough resolved to determine whether the coupling was ferromagnetic (S = 3 ground state) or antiferromagnetic (S = 2). The glass-forming 2-methyltetrahydrofuran solvent yields highly resolved Mössbauer spectra from which the following data have been extracted: (i) the ground state of 1 has S = 3 (J < 0); (ii) |J| > 15 cm(-1); (iii) the zero-field-splitting parameters are D = -1.1 cm(-1) and E/D = 0.02; (iv) the major component of the electric-field-gradient tensor is tilted ≈7° relative to the easy axis of magnetization determined by the MS = ±3 and ±2 doublets. The excited-state MS = ±2 doublet yields a narrow parallel-mode electron paramagnetic resonance signal at g = 8.03, which was used to probe the magnetic hyperfine splitting of (17)O-enriched O2. A theoretical model that considers spin-dependent electron transfer for the cases where the doubly occupied π* orbital of the superoxo ligand is either "in" or "out" of the plane defined by the bent Fe-OO moiety correctly predicts that 1 has an S = 3 ground state, in contrast to the density functional theory calculations for 1, which give a ground state with both the wrong spin and orbital configuration. This failure has been traced to a basis set superposition error in the interactions between the superoxo moiety and the adjacent five-membered rings of the BDPP ligand and signals a fundamental problem in the quantum chemistry of O2 activation. PMID:27159412

  17. Growth of ZnO thin films doped with (Mn & Co) by spin coating technique

    NASA Astrophysics Data System (ADS)

    Dhruvashi, Rawat, Kusum; Shishodia, P. K.

    2016-05-01

    ZnO thin films co-doped with Mn and Co have been deposited on glass substrates by spin coating technique. Structural, optical and magnetic properties have been investigated as a function of dopant concentration. X-ray diffraction has confirmed the growth of c-axis oriented polycrystalline thin films. No impurity phases have been detected corresponding to metal oxides within the limitation of x-ray diffraction. The optical bandgap has been evaluated from tauc's plots derived from the transmittance spectra in the wavelength range 350-900 nm. Surface morphology of the films has been observed by field emission scanning electron microscope. The field dependence of magnetization (M-H curve) measured by vibrating sample magnetometer shows the ferromagnetic behavior of the films at room temperature. The magnetization versus temperature (M-T) curve has also been measured under zero field cooled and field cooled conditions.

  18. Spatial and vectorial characterization of thermal relaxation using the spin-stand imaging technique

    NASA Astrophysics Data System (ADS)

    Tse, C.; Mircea, D. I.; Mayergoyz, I. D.; Andrei, P.; Krafft, C.

    2002-05-01

    The spatial and vectorial characterization of thermal relaxation of recorded magnetization patterns by using the spin-stand imaging technique [I. D. Mayergoyz et al., J. Appl. Phys. 87, 6824 (2000); 89, 6772 (2001)] is reported. In order to obtain such characterization, a recorded track is scanned at successive instants of time over periods of 70 hours. As a result, the spatial distributions of the read-back voltages (that constitute the "raw" images of the track) are consecutively collected. The images of the vectorial magnetization are then reconstructed and local magnetization relaxation rates are subsequently evaluated. It is demonstrated that the spatially inhomogeneous and vectorial nature of thermal relaxation of recorded patterns may result in temporal track broadening. It is found that this temporal track broadening is more pronounced for disks with higher coercivities.

  19. One-step electro-spinning/netting technique for controllably preparing polyurethane nano-fiber/net.

    PubMed

    Hu, Juanping; Wang, Xianfeng; Ding, Bin; Lin, Jinyou; Yu, Jianyong; Sun, Gang

    2011-11-01

    Electro-spinning/netting (ESN) as a cutting-edge technique evokes much interest because of its ability in the one-step preparation of versatile nano-fiber/net (NFN) membranes. Here, a controllable fabrication of polyurethane (PU) NFN membranes with attractive structures, consisting of common electrospun nanofibers and two-dimensional (2D) soap bubble-like structured nano-nets via an ESN process is reported. The unique nanoscaled NFN architecture can be finely controlled by regulating the solution properties and several ESN process parameters. The versatile PU nano-nets comprising interlinked nanowires with ultrathin diameters (5-40 nm) mean that the NFN structured membranes possess several excellent characteristics, such as an extremely large specific surface area, high porosity and large stacking density, which would be particularly useful for applications in ultrafiltration, special protective clothing, ultrasensitive sensors, catalyst support and so on. PMID:21858891

  20. Spatially-resolved spectroscopic technique for measuring optical properties of food

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantification of optical properties is important to understand light interaction with biological materials, and to develop effective optical sensing techniques for property characterization and quality measurement of food products. This chapter reviews spatially-resolved method, with the focus on f...

  1. Reflective and photoacoustic infrared spectroscopic techniques in assessment of binding media in paintings

    NASA Astrophysics Data System (ADS)

    Łojewski, Tomasz; Bagniuk, Jacek; Kołodziej, Andrzej; Łojewska, Joanna

    2011-11-01

    This study proposes a method to estimate the lipid content in binding media in paintings that can be used at any laboratory equipped with an infrared spectrometer. The lipid content estimator, termed greasiness index (GI), is defined as a ratio of lipid ν(C=O) and protein amide I bands at 1743 and 1635 cm-1, respectively. Three Fourier transform infrared (FTIR) sampling techniques were evaluated for GI determination: reflective attenuated total reflection—ATR, specular reflection microscopy— μSR and photoacoustic—PAS. A set of model painting samples containing three tempera binding media (casein, egg, egg + oil), seven pigments and one varnish type were used in the study. Multivariate analysis was used to evaluate the resulting data. A good reproducibility of GI was obtained by ATR and PAS but not with μSR. The discriminative power of the technique is higher for unvarnished samples, but, generally, the GI estimator can be used for the categorisation of binding media in large populations of painting samples analysed with the same FTIR technique (sampling technique, detection, etc.).

  2. Calculations of 21 Λ-S and 42 Ω states of BC molecule: Potential energy curves, spectroscopic parameters and spin-orbit coupling effect.

    PubMed

    Xing, Wei; Shi, Deheng; Sun, Jinfeng; Zhu, Zunlue

    2016-01-15

    The potential energy curves (PECs) were calculated for the 42 Ω states generated from the 21 Λ-S states (X(4)Σ(-), A(4)Π, B(4)Σ(-), a(2)Π, b(2)Σ(-), c(2)Δ, d(2)Σ(+), e(2)Π, 3(2)Π, 4(2)Π, 5(2)Π, 2(2)Σ(-), 3(2)Σ(-), 2(2)Σ(+), 3(2)Σ(+), 2(2)Δ, 3(2)Δ, 1(4)Σ(+), 2(4)Π, 1(4)Δ and 1(2)Φ), which originated from the lowest two dissociation channels, B((2)Pu)+C((3)Pg) and B((2)Pu)+C((1)Dg), of the BC molecule. The PECs were calculated for internuclear separations from 0.08 to 1.10 nm using the CASSCF method, which was followed by the icMRCI approach with the aug-cc-pV6Z basis set. Of these 21 Λ-S states, the e(2)Π, 2(2)Δ, 2(2)Σ(-), 4(2)Π, 1(2)Φ and 3(2)Δ possess the double wells. The A(4)Π, a(2)Π, c(2)Δ, 2(4)Π, 4(2)Π, 5(2)Π, 1(4)Δ and 1(2)Φ states are inverted with the spin-orbit coupling (SOC) effect taken into account. The first well of e(2)Π state and the second well of 4(2)Π and 2(2)Δ states do not have any vibrational states whether with or without the SOC effect included. All the Λ-S and Ω states involved in this paper are bound states. Scalar relativistic correction was included by the third-order Douglas-Kroll Hamiltonian approximation at the level of an aug-cc-pV5Z basis set. Core-valence correlation correction was included at the level of an aug-cc-pCV5Z basis set. The SOC effect was accounted for by the state interaction method with the Breit-Pauli Hamiltonian and the all-electron cc-pCV5Z basis set. The PECs of all the states were extrapolated to the complete basis set limit. The spectroscopic parameters were obtained. The vibrational properties of several Λ-S and Ω states with the relatively shallow wells were evaluated. The SOC effect on the spectroscopic parameters is not obvious for almost all the states. The spectroscopic properties reported in this paper can be expected to be reliably predicted ones. PMID:26476070

  3. Murillo's paintings revealed by spectroscopic techniques and dedicated laboratory-made micro X-ray diffraction.

    PubMed

    Duran, A; Siguenza, M B; Franquelo, M L; Jimenez de Haro, M C; Justo, A; Perez-Rodriguez, J L

    2010-06-25

    This paper describes one of the first case studies using micro-diffraction laboratory-made systems to analyse painting cross-sections. Pigments, such as lead white, vermilion, red ochre, red lac, lapis lazuli, smalt, lead tin yellow type I, massicot, ivory black, lamp black and malachite, were detected in cross-sections prepared from six Bartolomé Esteban Murillo paintings by micro-Raman and micro-XRD combined with complementary techniques (optical microscopy, SEM-EDS, and FT-IR). The use of micro-XRD was necessary due to the poor results obtained with conventional XRD. In some cases, pigment identification was only possible by combining results from the different analytical techniques utilised in this study. PMID:20541637

  4. Photon-in/photon-out spectroscopic techniques for materials analysis: some recent developments.

    PubMed

    Sham, Tsun-Kong

    2014-12-10

    Third-generation synchrotron light source technology has greatly improved the capabilities for materials analysis using tunable X-rays. Two such capabilities developed recently are reported herein - inverse partial fluorescence yield (IPFY) XANES (X-ray absorption near edge structure) and 2D XANES - XEOL (X-ray excited optical luminescence) in both the energy and time domain. These techniques take advantage of recent advances in soft X-ray solid state detector, optical spectrometer with a CCD detector and optical streak camera on a soft X-ray beamline as well as new data acquisition schemes. The studies of LiFePO4 materials for Li ion battery and solid solutions of GaN-ZnO nanostructures for water splitting are used to illustrate these capabilities. The prospects of these and related synchrotron photon-in photon-out techniques are also noted. PMID:24861360

  5. Microsampling techniques for infrared spectroscopic analysis of lunar and terrestrial minerals

    NASA Technical Reports Server (NTRS)

    Estep, P. A.; Kovach, J. J.; Karr, C.

    1973-01-01

    Microsampling techniques have been developed for infrared analysis of single mineral grains from lunar rocks and dusts, allowing a detailed molecular structure characterization of these complex fine-grained samples. The methods include special devices for isolating single grains, preparing micropellets from the grains, and obtaining in situ microspecular reflectance spectra from grains in polished rock samples. Although specifically developed for the work on lunar samples, the special techniques for single grain infrared analysis were found to be equally useful in studies of complex terrestrial mineral samples. For example, infrared microanalysis has contributed substantially in solving problems concerned with our natural resources, such as the structural characterization of minerals from commercial iron ores, marine deposits, coal, and fly ash derived from coal.

  6. Innovative combination of spectroscopic techniques to reveal nanoparticle fate in a crop plant

    NASA Astrophysics Data System (ADS)

    Larue, Camille; Castillo-Michel, Hiram; Stein, Ricardo J.; Fayard, Barbara; Pouyet, Emeline; Villanova, Julie; Magnin, Valérie; Pradas del Real, Ana-Elena; Trcera, Nicolas; Legros, Samuel; Sorieul, Stéphanie; Sarret, Géraldine

    2016-05-01

    Nanotechnology is the new industrial revolution of our century. Its development leads to an increasing use of nanoparticles and thus to their dissemination. Their fate in the environment is of great concern and especially their possible transfer in trophic chains might be an issue for food safety. However, so far our knowledge on this topic has been restricted by the lack of appropriate techniques to characterize their behavior in complex matrices. Here, we present in detail the use of cutting-edge beam-based techniques for nanoparticle in situ localization, quantification and speciation in a crop plant species (Lactuca sativa). Lettuce seedlings have been exposed to TiO2 and Ag nanoparticles and analyzed by inductively coupled plasma spectrometry, micro-particle induced X-ray emission coupled to Rutherford backscattering spectroscopy on nuclear microprobe, micro-X-ray fluorescence spectroscopy and X-ray absorption near edge structure spectroscopy. The benefits and drawbacks of each technique are discussed, and the types of information that can be drawn, for example on the translocation to edible parts, change of speciation within the plant, detoxification mechanisms, or impact on the plant ionome, are highlighted. Such type of coupled approach would be an asset for nanoparticle risk assessment.

  7. Quantitative determination of copper in a glass matrix using double pulse laser induced breakdown and electron paramagnetic resonance spectroscopic techniques.

    PubMed

    Khalil, Ahmed A I; Morsy, Mohamed A

    2016-07-01

    A series of lithium-lead-borate glasses of a variable copper oxide loading were quantitatively analyzed in this work using two distinct spectroscopic techniques, namely double pulse laser induced breakdown spectroscopy (DP-LIBS) and electron paramagnetic resonance (EPR). DP-LIBS results measured upon a combined nanosecond lasers irradiation running at 266nm and 1064nm pulses of a collinear configuration directed to the surface of borate glass samples with a known composition. This arrangement was employed to predict the electron's temperature (Te) and density (Ne) of the excited plasma from the recorded spectra. The intensity of elements' responses using this scheme is higher than that of single-pulse laser induced breakdown spectroscopy (SP-LIBS) setup under the same experimental conditions. On the other hand, the EPR data shows typical Cu (II) EPR-signals in the borate glass system that is networked at a distorted tetragonal Borate-arrangement. The signal intensity of the Cu (II) peak at g⊥=2.0596 has been used to quantify the Cu-content accurately in the glass matrix. Both techniques produced linear calibration curves of Cu-metals in glasses with excellent linear regression coefficient (R(2)) values. This study establishes a good correlation between DP-LIBS analysis of glass and the results obtained using EPR spectroscopy. The proposed protocols prove the great advantage of DP-LIBS system for the detection of a trace copper on the surface of glasses. PMID:27154655

  8. Development and applications of laser spectroscopic techniques related to combustion diagnostics

    NASA Astrophysics Data System (ADS)

    Aldén, Marcus

    2006-07-01

    Thanks to features as non-intrusiveness combined with high spatial and temporal resolution, various laser diagnostic techniques have during the last decades become of utmost importance for characterization of combustion related phenomena. In the following presentation some further development of the techniques will be highlighted aiming at a) surface temperatures using Thermographic Phosphors, TP, b) species specific, spatially and temporally resolved detection of species absorbing in the IR spectral region using polarization spectroscopy and Laser-induced fluorescence, and finally c) high speed visualization using a special designed laser system in combination with a framing camera. In terms of surface thermometry, Thermographic Phosphors have been used for many years for temperature measurements on solid surfaces. We have during the last years further developed and applied this technique for temperature measurements on burning surfaces and on materials going through phase shifts, e.g. pyrolysis and droplets. The basic principle behind this technique is to apply micron size particles to the surface of interest. By exciting the TP with a short pulse UV laser (ns), the phosphorescence will exhibit a behaviour where the spectral emission as well as the temporal decay are dependent on the temperature. It is thus possible to measure the temperature both in one and two dimensions. The presentation will include basic description of the technique as well as various applications, e.g in fire science, IC engines and gasturbines. Several of the species of interest for combustion/flow diagnostics exhibit a molecular structure which inhibits the use of conventional laser-induced fluorescence for spatially and spectrally resolved measurements. We have during the last years investigated the use of excitation and detection in the infrared region of the spectrum. Here, it is possible to detect both carbonmono/dioxide, water as well as species specific hydrocarbons. The techniques

  9. Raman spectroscopic studies of thin film carbon nanostructures deposited using electro deposition technique

    NASA Astrophysics Data System (ADS)

    Dayal, Saurabh; Sasi, Arshali; Jhariya, Sapna; Sasikumar, C.

    2016-05-01

    In the present work our focus is to synthesize carbon nanostructures (CNS) by electro deposition technique without using any surface pretreatment or catalyst preparation before CNS formation. The process were carried out at significantly low voltage and at low temperature as reported elsewhere. Further the samples were characterized using different characterization tools such as SEM and Raman spectroscopy. The SEM results showed the fibres or tubular like morphology. Raman spectra shows strong finger print at 1600 cm-1 (G peak), 1350 cm-1 (D peak) along with the radial breathing mode (RBM) between 150cm-1 to 300 cm-1. This confirms the formation of tubular carbon nanostructures.

  10. The analytical investigations of ancient pottery from Kaveripakkam, Vellore dist, Tamilnadu by spectroscopic techniques.

    PubMed

    Ravisankar, R; Naseerutheen, A; Annamalai, G Raja; Chandrasekaran, A; Rajalakshmi, A; Kanagasabapathy, K V; Prasad, M V R; Satpathy, K K

    2014-01-01

    Analytical investigations using Fourier Transform infrared spectroscopy (FT-IR), Powder X-ray Diffraction (PXRD), Thermal Analysis (TG-DTA), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Fluorescence Spectrometry (EDXRF) were carried out on ancient pottery fragments from Kaveripakkam, in order to outline manufacturing skills, technology information, firing condition and temperature of potteries. The whole set of data showed the firing temperature in the range of 800-900°C. The analytical characterization of the potsherds, by different complimentary techniques has allowed to identifying the raw materials and technology applied by the ancient artisans. PMID:24287055

  11. Chemical and morphological changes in hydrochars derived from microcrystalline cellulose and investigated by chromatographic, spectroscopic and adsorption techniques.

    PubMed

    Diakité, Mamadou; Paul, Andrea; Jäger, Christian; Pielert, Judith; Mumme, Jan

    2013-12-01

    Hydrothermal carbonization (HTC) can be used for converting the biomass into a carbon-rich material, whose application as a fuel requires higher heating value, whereas soil amendment needs stable carbon. This work was focused on the characterization of hydrochars derived from microcrystalline cellulose. The chars were investigated using elemental analysis, Brunauer-Emmett-Teller technique, nuclear magnetic resonance spectroscopy, Raman, Fourier transform infrared, and electron spin resonance spectroscopy. Severity in temperature between 230 and 270°C with reaction times between 2 and 10 h only affect the carbon content moderately. The results show that aromatization of HTC chars correlates well with temperature, which was further supported by the increase of organic radicals with decreasing g values at higher temperatures. Based on these results, the energetic use of chars favors mild HTC (T<230°C and t≤6 h), while the soil amendement favors serve conditions (T≥230°C, and t>6 h). PMID:24157681

  12. Refining Techniques for the Spectroscopic Detection of Reflected Light from Exoplanets

    NASA Astrophysics Data System (ADS)

    Roy, Arpita; Bender, Chad; Mahadevan, Suvrath

    2015-12-01

    The detection of reflected light from exoplanets provides a direct measure of planetary mass as well as a powerful probe of atmospheric composition and albedo. However, close-in giant planets which provide the largest planet-to-star flux ratios are dim in the optical. With contrasts at the level of 10^-5, the direct detection of these present a severe technical challenge to current instruments, and require both large aperture telescopes for high signal-to-noise ratio observations, and a stabilized spectrograph for stable instrument profiles. Leveraging the heritage and stability of the HARPS spectrograph, Martins et al (2015) recently published evidence of a direct detection of the historic exoplanet 51 Peg b, using the stellar mask cross-correlation technique. We attempt to expand upon their results with independent spectral and CCF reductions, using a two-template cross-correlation technique that can potentially be tuned to match the planetary signal and probe models of the albedo. By cross-correlating against a spectrum rather than a mask, we access the full information content in the lines, but must ensure proper telluric correction to mitigate the possibility of overwhelming the small planetary signal with terrestrial features. We are on the verge of confidently recovering planetary albedos for close-in giant planets, while also refining predictive and analytical tools that will come into their full capability with the arrival of the next generation of planet characterizing instruments, such as ESPRESSO on VLT and HIRES on E-ELT.

  13. Spectroscopic techniques applied to the characterization of decorated potteries from Caltagirone (Sicily, Italy)

    NASA Astrophysics Data System (ADS)

    Barilaro, D.; Barone, G.; Crupi, V.; Donato, M. G.; Majolino, D.; Messina, G.; Ponterio, R.

    2005-06-01

    The aim of the present work is the characterization of decorated pottery samples from Caltagirone (Sicily, Italy), a renowned production centre of this kind of artwork. These fragments were found during archaeological excavations and were attributed to historical periods extremely far in time from each other (from XVIII century b.C. to XVI a.C.). Therefore, we expect that the manufacture techniques result rather different over so long time. The measurements, performed by Fourier Transform-InfraRed (FT-IR) absorbance and micro-Raman scattering, allowed us a non-destructive study of so precious artefacts. Some pigments were identified, various elements of ceramic paste and glazed layer were characterized.

  14. Artificial tektites: an experimental technique for capturing the shapes of spinning drops

    NASA Astrophysics Data System (ADS)

    Baldwin, K. A.

    2014-12-01

    Tektites are small stones formed from rapidly cooling drops of molten rock ejected from high velocity asteroid impacts with the Earth, that freeze into a myriad of shapes during flight. Many splash-form tektites have an elongated or dumb-bell shape owing to their rotation prior to solidification[1]. Here we present a novel method for creating 'artificial tektites' from spinning drops of molten wax, using diamagnetic levitation to suspend the drops[2]. We find that the solid wax models produced this way are the stable equilibrium shapes of a spinning liquid droplet held together by surface tension. In addition to the geophysical interest in tektite formation, the stable equilibrium shapes of liquid drops have implications for many physical phenomena, covering a wide range of length scales, from nuclear physics (e.g. in studies of rapidly rotating atomic nuclei), to astrophysics (e.g. in studies of the shapes of astronomical bodies such as asteroids, rapidly rotating stars and event horizons of rotating black holes). For liquid drops bound by surface tension, analytical and numerical methods predict a series of stable equilibrium shapes with increasing angular momentum. Slowly spinning drops have an oblate-like shape. With increasing angular momentum these shapes become secularly unstable to a series of triaxial pseudo-ellipsoids that then evolve into a family of two-lobed 'dumb-bell' shapes as the angular momentum is increased still further. Our experimental method allows accurate measurements of the drops to be taken, which are useful to validate numerical models. This method has provided a means for observing tektite formation, and has additionally confirmed experimentally the stable equilibrium shapes of liquid drops, distinct from the equivalent shapes of rotating astronomical bodies. Potentially, this technique could be applied to observe the non-equilibrium dynamic processes that are also important in real tektite formation, involving, e.g. viscoelastic

  15. 3D GRASE PROPELLER: Improved Image Acquisition Technique for Arterial Spin Labeling Perfusion Imaging

    PubMed Central

    Tan, Huan; Hoge, W. Scott; Hamilton, Craig A.; Günther, Matthias; Kraft, Robert A.

    2014-01-01

    Arterial spin labeling (ASL) is a non-invasive technique that can quantitatively measure cerebral blood flow (CBF). While traditionally ASL employs 2D EPI or spiral acquisition trajectories, single-shot 3D GRASE is gaining popularity in ASL due to inherent SNR advantage and spatial coverage. However, a major limitation of 3D GRASE is through-plane blurring caused by T2 decay. A novel technique combining 3D GRASE and a PROPELLER trajectory (3DGP) is presented to minimize through-plane blurring without sacrificing perfusion sensitivity or increasing total scan time. Full brain perfusion images were acquired at a 3×3×5mm3 nominal voxel size with Q2TIPS-FAIR as the ASL preparation sequence. Data from 5 healthy subjects was acquired on a GE 1.5T scanner in less than 4 minutes per subject. While showing good agreement in CBF quantification with 3D GRASE, 3DGP demonstrated reduced through-plane blurring, improved anatomical details, high repeatability and robustness against motion, making it suitable for routine clinical use. PMID:21254211

  16. Free radical scavenging actions of hippocampal metallothionein isoforms and of antimetallothioneins: an electron spin resonance spectroscopic study.

    PubMed

    Kumari, M V; Hiramatsu, M; Ebadi, M

    2000-05-01

    The high concentration of zinc in the hippocampal mossy fiber axon boutons is localized in the vesicles and is mobilized by exocytosis of the zinc-laden vesicles. Furthermore, the mammalian hippocampi contain metallothionein (MT) isoforms which regulate the steady state concentration of zinc, an important antioxidant. Indeed, zinc deprivation leads to an increased lipid peroxidation, reduces the activity of Cu++-Zn++ superoxide dismutase, and protect against oxidative stress such as exposure to ultraviolet A irradiation. By employing electron spin resonance (ESR) spectroscopy, we have demonstrated that rat hippocampal MT isoforms 1 and 2 were able to scavenge 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl radicals (*OH) generated in a Fenton reaction, and superoxide anions (O2*-) generated by the hypoxanthine and xanthine oxidase system. In addition, MT-1 isoform protected the isolated hepatocytes from lipid peroxidation as determined by thiobarbituric acid bound malondialdehyde. MT antibodies scavenged DPPH radicals, hydroxyl radicals and reactive oxygen species but not superoxide anions. The results of these studies suggest that although both isoforms of MT are able to scavenge free radicals, the MT-1 appears to be a superior scavenger of superoxide anions and 1,1-diphenyl-2-picrylhydrazyl radicals. Moreover, antibodies formed against MT isoform retain some, but not all, free radical scavenging actions exhibited by MT-1 and MT-2. PMID:10872749

  17. The Book of Kells: a non-invasive MOLAB investigation by complementary spectroscopic techniques.

    PubMed

    Doherty, B; Daveri, A; Clementi, C; Romani, A; Bioletti, S; Brunetti, B; Sgamellotti, A; Miliani, C

    2013-11-01

    This paper highlights the efficacy of non-invasive portable spectroscopy for assessing the execution technique and constituent materials in one of the most important medieval manuscripts, the Book of Kells. An aimed campaign of in situ measurements by the MObile LABoratory (MOLAB) has analyzed its elemental composition and vibrational and electronic molecular properties. The ample analytical toolbox has afforded complementary diagnostic information of the pigment palette permitting the characterization of both inorganic and organic materials as pigments and dyes in the white, purple, blue, red, orange, green and black areas. In particular, the novel widespread use of calcinated gypsum (anhydrite) as both a white pigment and in correlation to the organic dyes in this manuscript has been noted. The non-invasive identification of the organic dye orchil is significant considering its rare non invasive detection in medieval manuscripts. Finally the occurrence of particular alterations of the organic black areas giving rise to calcium carboxylate and calcium oxalate has been specifically highlighted. Importantly, this work elaborates complex aspects of the employed painting materials which have given rise to numerous significant points of interest for a more elaborate understanding of this Irish treasure. PMID:23850791

  18. The Book of Kells: A non-invasive MOLAB investigation by complementary spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Doherty, B.; Daveri, A.; Clementi, C.; Romani, A.; Bioletti, S.; Brunetti, B.; Sgamellotti, A.; Miliani, C.

    2013-11-01

    This paper highlights the efficacy of non-invasive portable spectroscopy for assessing the execution technique and constituent materials in one of the most important medieval manuscripts, the Book of Kells. An aimed campaign of in situ measurements by the MObile LABoratory (MOLAB) has analyzed its elemental composition and vibrational and electronic molecular properties. The ample analytical toolbox has afforded complementary diagnostic information of the pigment palette permitting the characterization of both inorganic and organic materials as pigments and dyes in the white, purple, blue, red, orange, green and black areas. In particular, the novel widespread use of calcinated gypsum (anhydrite) as both a white pigment and in correlation to the organic dyes in this manuscript has been noted. The non-invasive identification of the organic dye orchil is significant considering its rare non invasive detection in medieval manuscripts. Finally the occurrence of particular alterations of the organic black areas giving rise to calcium carboxylate and calcium oxalate has been specifically highlighted. Importantly, this work elaborates complex aspects of the employed painting materials which have given rise to numerous significant points of interest for a more elaborate understanding of this Irish treasure.

  19. In vitro DNA binding studies of anticancer drug idarubicin using spectroscopic techniques.

    PubMed

    Ozluer, Can; Kara, Hayriye Eda Satana

    2014-09-01

    The interaction between idarubicin and double stranded deoxyribonucleic acid (ds-DNA) was investigated by UV-VIS spectrophotometry, fluorescence and Raman spectroscopy techniques. The absorption spectra of idarubicin with ds-DNA showed a slight red shift and hypochromic effect. In the fluorescence experiments, emission peaks were decreased by adding ds-DNA. Using ethidium bromide (ETB) as a fluorescence probe, fluorescence quenching of the emission peak was observed in the ETB-DNA system when idarubicin was added. Moreover, similar results were obtained in Raman spectroscopy. Binding constants of idarubicin with ds-DNA were determined as 5.14×10(5) M(-1) and 5.8×10(5) M(-1) for UV-VIS spectrophotometry and fluorescence spectroscopy, respectively. The large binding constant indicated that idarubicin has a high affinity with ds-DNA. All the evidences indicated that the binding mode of idarubicin with DNA was an intercalative binding. Furthermore, quantitative determination of idarubicin in pharmaceutical formulation was done. PMID:24911270

  20. Rapid non-destructive assessment of pork edible quality by using VIS/NIR spectroscopic technique

    NASA Astrophysics Data System (ADS)

    Zhang, Leilei; Peng, Yankun; Dhakal, Sagar; Song, Yulin; Zhao, Juan; Zhao, Songwei

    2013-05-01

    The objectives of this research were to develop a rapid non-destructive method to evaluate the edible quality of chilled pork. A total of 42 samples were packed in seal plastic bags and stored at 4°C for 1 to 21 days. Reflectance spectra were collected from visible/near-infrared spectroscopy system in the range of 400nm to 1100nm. Microbiological, physicochemical and organoleptic characteristics such as the total viable counts (TVC), total volatile basic-nitrogen (TVB-N), pH value and color parameters L* were determined to appraise pork edible quality. Savitzky-Golay (SG) based on five and eleven smoothing points, Multiple Scattering Correlation (MSC) and first derivative pre-processing methods were employed to eliminate the spectra noise. The support vector machines (SVM) and partial least square regression (PLSR) were applied to establish prediction models using the de-noised spectra. A linear correlation was developed between the VIS/NIR spectroscopy and parameters such as TVC, TVB-N, pH and color parameter L* indexes, which could gain prediction results with Rv of 0.931, 0.844, 0.805 and 0.852, respectively. The results demonstrated that VIS/NIR spectroscopy technique combined with SVM possesses a powerful assessment capability. It can provide a potential tool for detecting pork edible quality rapidly and non-destructively.

  1. Classical Raman spectroscopic studies of NADH and NAD+ bound to liver alcohol dehydrogenase by difference techniques

    SciTech Connect

    Chen, D.; Yue, K.T.; Martin, C.; Rhee, K.W.; Sloan, D.; Callender, R.

    1987-07-28

    We report the Raman spectra of reduced and oxidized nicotinamide adenine dinucleotide (NADH and NAD+, respectively) and adenosine 5'-diphosphate ribose (ADPR) when bound to the coenzyme site of liver alcohol dehydrogenase (LADH). The bound NADH spectrum is calculated by taking the classical Raman difference spectrum of the binary complex, LADH/NADH, with that of LADH. We have investigated how the bound NADH spectrum is affected when the ternary complexes with inhibitors are formed with dimethyl sulfoxide (Me2SO) or isobutyramide (IBA), i.e., LADH/NADH/Me2SO or LADH/NADH/IBA. Similarly, the difference spectra of LADH/NAD+/pyrazole or LADH/ADPR with LADH are calculated. The magnitude of these difference spectra is on the order of a few percent of the protein Raman spectrum. We report and discuss the experimental configuration and control procedures we use in reliably calculating such small difference signals. These sensitive difference techniques could be applied to a large number of problems where the classical Raman spectrum of a ''small'' molecule, like adenine, bound to the active site of a protein is of interest. The spectrum of bound ADPR allows an assignment of the bands of the bound NADH and NAD+ spectra to normal coordinates located primarily on either the nicotinamide or the adenine moiety. By comparing the spectra of the bound coenzymes with model compound data and through the use of deuterated compounds, we confirm and characterize how the adenine moiety is involved in coenzyme binding and discuss the validity of the suggestion that the adenine ring is protonated upon binding. The nicotinamide moiety of NADH shows significant molecular changes upon binding.

  2. Development and Experimental Testing of an Optical Micro-Spectroscopic Technique Incorporating True Line-Scan Excitation

    PubMed Central

    Biener, Gabriel; Stoneman, Michael R.; Acbas, Gheorghe; Holz, Jessica D.; Orlova, Marianna; Komarova, Liudmila; Kuchin, Sergei; Raicu, Valerică

    2014-01-01

    Multiphoton micro-spectroscopy, employing diffraction optics and electron-multiplying CCD (EMCCD) cameras, is a suitable method for determining protein complex stoichiometry, quaternary structure, and spatial distribution in living cells using Förster resonance energy transfer (FRET) imaging. The method provides highly resolved spectra of molecules or molecular complexes at each image pixel, and it does so on a timescale shorter than that of molecular diffusion, which scrambles the spectral information. Acquisition of an entire spectrally resolved image, however, is slower than that of broad-bandwidth microscopes because it takes longer times to collect the same number of photons at each emission wavelength as in a broad bandwidth. Here, we demonstrate an optical micro-spectroscopic scheme that employs a laser beam shaped into a line to excite in parallel multiple sample voxels. The method presents dramatically increased sensitivity and/or acquisition speed and, at the same time, has excellent spatial and spectral resolution, similar to point-scan configurations. When applied to FRET imaging using an oligomeric FRET construct expressed in living cells and consisting of a FRET acceptor linked to three donors, the technique based on line-shaped excitation provides higher accuracy compared to the point-scan approach, and it reduces artifacts caused by photobleaching and other undesired photophysical effects. PMID:24378851

  3. Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Decesari, S.; Allan, J.; Plass-Duelmer, C.; Williams, B. J.; Paglione, M.; Facchini, M. C.; O'Dowd, C.; Harrison, R. M.; Gietl, J. K.; Coe, H.; Giulianelli, L.; Gobbi, G. P.; Lanconelli, C.; Carbone, C.; Worsnop, D.; Lambe, A. T.; Ahern, A. T.; Moretti, F.; Tagliavini, E.; Elste, T.; Gilde, S.; Zhang, Y.; Dall'Osto, M.

    2014-04-01

    The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterized by a less dense urbanization. We present here the results obtained in San Pietro Capofiume, which is located in a sparsely inhabited sector of the Po Valley, Italy. The experiment was carried out in summer 2009 in the framework of the EUCAARI project ("European Integrated Project on Aerosol, Cloud Climate Aerosol Interaction"). For the first time in Europe, six state-of-the-art techniques were used in parallel: (1) on-line TSI aerosol time-of-flight mass spectrometer (ATOFMS), (2) on-line Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-TOF-AMS), (3) soot particle aerosol mass spectrometer (SP-AMS), (4) on-line high resolution time-of-flight mass spectrometer-thermal desorption aerosol gas chromatograph (HR-ToFMS-TAG), (5) off-line twelve-hour resolution proton nuclear magnetic resonance (H-NMR) spectroscopy, and (6) chemical ionization mass spectrometry (CIMS) for the analysis of gas-phase precursors of secondary aerosol. Data from each aerosol spectroscopic method were analysed individually following ad-hoc tools (i.e. PMF for AMS, Art-2a for ATOFMS). The results obtained from each techniques are herein presented and compared. This allows us to clearly link the modifications in aerosol chemical composition to transitions in air mass origin and meteorological regimes. Under stagnant conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC

  4. MOS solar cells with oxides deposited by sol-gel spin-coating techniques

    SciTech Connect

    Huang, Chia-Hong; Chang, Chung-Cheng; Tsai, Jung-Hui

    2013-06-15

    The metal-oxide-semiconductor (MOS) solar cells with sol-gel derived silicon dioxides (SiO{sub 2}) deposited by spin coating are proposed in this study. The sol-gel derived SiO{sub 2} layer is prepared at low temperature of 450 Degree-Sign C. Such processes are simple and low-cost. These techniques are, therefore, useful for largescale and large-amount manufacturing in MOS solar cells. It is observed that the short-circuit current (I{sub sc}) of 2.48 mA, the open-circuit voltage (V{sub os}) of 0.44 V, the fill factor (FF) of 0.46 and the conversion efficiency ({eta}%) of 2.01% were obtained by means of the current-voltage (I-V) measurements under AM 1.5 (100 mW/cm{sup 2}) irradiance at 25 Degree-Sign C in the MOS solar cell with sol-gel derived SiO{sub 2}.

  5. Arterial spin tagging fMRI in continuous overt speech production compared to BOLD technique

    NASA Astrophysics Data System (ADS)

    Kemeny, Stefan; Ye, Frank; Braun, Allen

    2003-05-01

    Conventional BOLD fMRI has limited use in overt speech paradigms, due to movement and susceptibility artifacts. Our study used an arterial spin-tagging (AST) sequence to quantify focal brain activation in a continuous speech task. Furthermore, we compared the results to conventional BOLD fMRI. The ASSIST sequence was used to obtain transverse perfusion images of the brain, acquired on a 1.5T GE-Signa scanner. Three conditions were alternated in a block design: generation of complete sentences, nonsense syllables and rest with continuous and overt speech production. For 4 normal volunteers, task-related perfusion maps with quantified rCBF and rCBV values were calculated and activations were mapped to the MNI brain. The same paradigm was scanned with BOLD contrast fMRI in separate, independent scans and data from 6 subjects were analyzed using SPM99. Using the AST sequence, we could reliably identify focal brain activation in an overt continuous speech paradigm, and the activations observed were consistent with previous PET studies. We found differential activation at increasing levels of speech production with a focus in the left insula and opercular IFG related to the production of sentences at a syntactic level as opposed to nonsense syllable production. The BOLD technique failed to identify some of these activation foci, possibly due to decreased SNR and artifacts.

  6. New spectroscopic tools and techniques for characterizing M dwarfs and discovering their planets in the near-infrared

    NASA Astrophysics Data System (ADS)

    Terrien, Ryan C.

    M dwarfs are the least massive and most common stars in the Galaxy. Due to their prevalence and long lifetimes, these diminutive stars play an outsize role in several fields of astronomical study. In particular, it is now known that they commonly host planetary systems, and may be the most common hosts of Earth-size, rocky planets in the habitable zone. A comprehensive understanding of M dwarfs is crucial for understanding the origins and conditions of their planetary systems, including their potential habitability. Such an understanding depends on methods for precisely and accurately measuring their properties. These tools have broader applicability as well, underlying the use of M dwarfs as fossils of Galactic evolution, and helping to constrain the structures and interiors of these stars. The measurement of the fundamental parameters of M dwarfs is encumbered by their spectral complexity. Unlike stars of spectral type F, G, or K that are similar to our G type Sun, whose spectra are dominated by continuum emission and atomic features, the cool atmospheres of M dwarfs are dominated by complex molecular absorption. Another challenge for studies of M dwarfs is that these stars are optically faint, emitting much of their radiation in the near-infrared (NIR). The availability and performance of NIR spectrographs have lagged behind those of optical spectrographs due to the challenges of producing low-noise, high-sensitivity NIR detector arrays, which have only recently become available. This thesis discusses two related lines of work that address these challenges, motivated by the development of the Habitable Zone Planet Finder (HPF), a NIR radial velocity (RV) spectrograph under development at Penn State that will search for and confirm planets around nearby M dwarfs. This work includes the development and application of new NIR spectroscopic techniques for characterizing M dwarfs, and the development and optimization of new NIR instrumentation for HPF. The first line

  7. A comparison investigation of DNP-binding effects to HSA and HTF by spectroscopic and molecular modeling techniques.

    PubMed

    Zolfagharzadeh, Mahboobeh; Pirouzi, Maliheh; Asoodeh, Ahmad; Saberi, Mohammad Reza; Chamani, Jamshidkhan

    2014-12-01

    This paper describes the interaction between 2,4-dinitrophenol (DNP) with the two drug carrier proteins - human serum albumin (HSA) and human holo transferrin (HTF). Hence, binding characteristics of DNP to HSA and HTF were analyzed by spectroscopic and molecular modeling techniques. Based on results obtained from fluorescence spectroscopy, DNP had a strong ability to quench the intrinsic fluorescence of HSA and HTF through a static quenching procedure. The binding constant and the number of binding sites were calculated as 2.3 × 10(11) M(-1) and .98 for HSA, and 1.7 × 10(11) M(-1) and 1.06 for HTF, respectively. In addition, synchronous fluorescence results showed that the microenvironment of Trp had a slight tendency of increasing its hydrophobicity, whereas the microenvironment of the Tyr residues of HSA did not change and that of HTF showed a significant trend (red shift of about 4 nm) of an increase in polarity. The distance between donor and acceptor was obtained by the Förster energy according to fluorescence resonance energy transfer, and was found to be 3.99 and 3.72 nm for HSA and HTF, respectively. The critical induced aggregation concentration (CCIAC) of the drug on both proteins was determined and confirmed by an inflection point of the zeta potential behavior. Circular dichroism data revealed that the presence of DNP caused a decrease of the α-helical content of HSA and HTF, and induced a remarkable mild denaturation of both proteins. The molecular modeling data confirmed our experimental results. This study is deemed useful for determining drug dosage. PMID:24125112

  8. Determination of acetamiprid partial-intercalative binding to DNA by use of spectroscopic, chemometrics, and molecular docking techniques.

    PubMed

    Zhang, Yue; Zhang, Guowen; Zhou, Xiaoyue; Li, Yu

    2013-11-01

    Acetamiprid (ACT) is an insecticide widely used for controlling a variety of insect pests. The binding mode associated with calf thymus DNA (ctDNA) upon interaction with ACT was determined using spectroscopic, chemometrics, and molecular docking techniques to clarify the interaction mechanism at the molecular level. Fluorescence titration suggested that the fluorescence quenching of ACT by ctDNA is a static procedure. The binding constants between ACT and ctDNA at different temperatures were calculated to be of the order 10(3)-10(4) L mol(-1). The positive values of enthalpy and entropy change suggested that the binding process is primarily driven by hydrophobic interactions. Multivariate curve resolution-alternating least squares (MCR-ALS), a chemometrics approach, was used to resolve the expanded UV-visible spectral data matrix. The concentration profiles and the spectra for the three reaction components (ACT, ctDNA, and ACT-ctDNA complex) of the system, which formed a highly overlapping composite response, were then successfully obtained and used to evaluate the progress of ACT interacting with ctDNA. The results of the single-stranded ctDNA and iodide quenching experiments, ctDNA-melting investigations, and viscosity measurements indicated that ACT binds to ctDNA by means of a partial intercalation. Molecular docking studies showed that the specific binding site is mainly located between the ACT and G-C base pairs of ctDNA. This docking prediction was confirmed by use of Fourier-transform infrared (FT-IR) spectral analysis. Results from circular dichroism (CD) spectroscopy revealed that ACT induced a conformational change from the B-ctDNA form to the A-ctDNA form. PMID:23975088

  9. Measurements of the aerosol chemical composition and mixing state in the Po Valley using multiple spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Decesari, S.; Allan, J.; Plass-Duelmer, C.; Williams, B. J.; Paglione, M.; Facchini, M. C.; O'Dowd, C.; Harrison, R. M.; Gietl, J. K.; Coe, H.; Giulianelli, L.; Gobbi, G. P.; Lanconelli, C.; Carbone, C.; Worsnop, D.; Lambe, A. T.; Ahern, A. T.; Moretti, F.; Tagliavini, E.; Elste, T.; Gilge, S.; Zhang, Y.; Dall'Osto, M.

    2014-11-01

    The use of co-located multiple spectroscopic techniques can provide detailed information on the atmospheric processes regulating aerosol chemical composition and mixing state. So far, field campaigns heavily equipped with aerosol mass spectrometers have been carried out mainly in large conurbations and in areas directly affected by their outflow, whereas lesser efforts have been dedicated to continental areas characterised by a less dense urbanisation. We present here the results obtained at a background site in the Po Valley, Italy, in summer 2009. For the first time in Europe, six state-of-the-art spectrometric techniques were used in parallel: aerosol time-of-flight mass spectrometer (ATOFMS), two aerosol mass spectrometers (high-resolution time-of-flight aerosol mass spectrometer - HR-ToF-AMS and soot particle aerosol mass spectrometer - SP-AMS), thermal desorption aerosol gas chromatography (TAG), chemical ionisation mass spectrometry (CIMS) and (offline) proton nuclear magnetic resonance (1H-NMR) spectroscopy. The results indicate that, under high-pressure conditions, atmospheric stratification at night and early morning hours led to the accumulation of aerosols produced by anthropogenic sources distributed over the Po Valley plain. Such aerosols include primary components such as black carbon (BC), secondary semivolatile compounds such as ammonium nitrate and amines and a class of monocarboxylic acids which correspond to the AMS cooking organic aerosol (COA) already identified in urban areas. In daytime, the entrainment of aged air masses in the mixing layer is responsible for the accumulation of low-volatility oxygenated organic aerosol (LV-OOA) and also for the recycling of non-volatile primary species such as black carbon. According to organic aerosol source apportionment, anthropogenic aerosols accumulating in the lower layers overnight accounted for 38% of organic aerosol mass on average, another 21% was accounted for by aerosols recirculated in

  10. MnO spin-wave dispersion curves from neutron powder diffraction

    SciTech Connect

    Goodwin, Andrew L.; Dove, Martin T.; Tucker, Matthew G.; Keen, David A.

    2007-02-15

    We describe a model-independent approach for the extraction of spin-wave dispersion curves from powder neutron total scattering data. Our approach is based on a statistical analysis of real-space spin configurations to calculate spin-dynamical quantities. The RMCPROFILE implementation of the reverse Monte Carlo refinement process is used to generate a large ensemble of supercell spin configurations from MnO powder diffraction data collected at 100 K. Our analysis of these configurations gives spin-wave dispersion curves for MnO that agree well with those determined independently using neutron triple-axis spectroscopic techniques.

  11. Study of anisotropy of spin cast and vapor deposited polyimide films using internal reflection techniques

    SciTech Connect

    Liberman, V.

    1996-11-01

    We have compared anisotropy of spin cast and vapor deposited polyimide (VDP) films, using internal reflection infrared spectroscopy. The films were deposited directly on the internal reflection element. We find that spin cast films are more anisotropic than their VDP counterparts, with the polyimide chains tending to align parallel to the substrate. Both films are found to contain more and less ordered regions. Within the ordered regions, the plane of the phenyl ring tends to align parallel to the substrate.

  12. Frequency-domain optical probing of coherent spins in nanocrystal quantum dots.

    PubMed

    Frey, J A; Berezovsky, J

    2012-08-27

    Spin-photon interactions such as the Faraday effect provide techniques for measuring coherent spin dynamics in semiconductors. In contrast to typical ultrafast pulsed laser techniques, which measure spin dynamics in the time domain with an intense, spectrally broad probe pulse, we demonstrate a frequency-domain spin-photon resonance effect using modulated continuous-wave lasers which enables measurement of GHz-scale coherent spin dynamics in semiconductors with minimal spectral linewidth. This technique permits high-resolution spectroscopic measurements not possible with ultrafast methods. We have employed this effect to observe coherent spin dynamics in CdSe nanocrystals using standard diode lasers. By fitting the results to the expected model, we extract electron g-factors, and spin coherence and dephasing times in agreement with time-domain measurements. PMID:23037054

  13. Nondestructive and Rapid Concurrent Estimation of Paracetamol and Nimesulide in Their Combined Dosage Form Using Raman Spectroscopic Technique

    PubMed Central

    Lakhwani, Gargi R.; Sherikar, O. D.; Mehta, Priti J.

    2013-01-01

    A rapid, nondestructive Raman spectroscopic method was developed for quantitative estimation of paracetamol and nimesulide in their combined dosage form. A Raman univariate calibration model was developed by measuring the peak intensities of paracetamol and nimesulide at 853 cm−1 and 1336 cm−1, respectively. The developed method was successfully applied for in situ, concurrent estimation of paracetamol and nimesulide in their combined dosage and method was also validated according to International Conference on Harmonisation guidelines. Thus, the developed Raman spectroscopic method can be applied for simultaneous estimation of paracetamol and nimesulide in their combined dosage form as a process analytical technology tool by pharmaceutical industries for routine quality control. PMID:24019571

  14. Spectroscopic analysis of solar and cosmic X-ray spectra. 1: The nature of cosmic X-ray spectra and proposed analytical techniques

    NASA Technical Reports Server (NTRS)

    Walker, A. B. C., Jr.

    1975-01-01

    Techniques for the study of the solar corona are reviewed as an introduction to a discussion of modifications required for the study of cosmic sources. Spectroscopic analysis of individual sources and the interstellar medium is considered. The latter was studied via analysis of its effect on the spectra of selected individual sources. The effects of various characteristics of the ISM, including the presence of grains, molecules, and ionization, are first discussed, and the development of ISM models is described. The expected spectral structure of individual cosmic sources is then reviewed with emphasis on supernovae remnants and binary X-ray sources. The observational and analytical requirements imposed by the characteristics of these sources are identified, and prospects for the analysis of abundances and the study of physical parameters within them are assessed. Prospects for the spectroscopic study of other classes of X-ray sources are also discussed.

  15. Spectroscopic data, spin-orbit functions, and revised analysis of strong perturbative interactions for the A {sup 1{Sigma}+} and b {sup 3{Pi}} states of RbCs

    SciTech Connect

    Docenko, O.; Tamanis, M.; Ferber, R.; Bergeman, T.; Kotochigova, S.; Stolyarov, A. V.

    2010-04-15

    The current interest in producing ultracold RbCs molecules by optical excitation from weakly bound Feshbach resonances and stimulated decay to the absolute ground state requires detailed analyses of the intermediate excited states. In this study, we present two sets of experimental Fourier-transform spectroscopic data of the A {sup 1{Sigma}+}-b {sup 3{Pi}} complex. The A-b mixed vibrational levels are the most likely candidates to be intermediates in the molecular formation. The more recent and more accurate data set is from mixed A-b{yields}X transitions, while the second is derived in large part from (4) {sup 1{Sigma}+{yields}}A-b emission and extends to higher A-b energy levels. From a detailed analysis of the spectroscopic data we obtain term values which allow one to construct potentials and spin-orbit functions. Vibrational numbering of the A state has been raised by one quantum over a previous report [T. Bergeman et al., Phys. Rev. A 67, 050501 (2003)] while the numbering of the b state is established with a considerable degree of certainty with help of data on the {sup 85}Rb{sup 133}Cs and {sup 87}Rb{sup 133}Cs isotopomers. In addition, we have performed calculations of spin-orbit functions by two distinct methods. The fitted spin-orbit coupling matrix element between the two {Omega}{sup p}=0{sup +} states, A {sup 1{Sigma}+} and b {sup 3{Pi}}{sub 0+}, happens to agree rather well with the results from both of these methods, while for the diagonal b {sup 3{Pi}} state spin-orbit function, the fitted function agrees fairly well with that obtained by the other method.

  16. Spin wave study and optical properties in Fe-doped ZnO thin films prepared by spray pyrolysis technique

    NASA Astrophysics Data System (ADS)

    Lmai, F.; Moubah, R.; El Amiri, A.; Abid, Y.; Soumahoro, I.; Hassanain, N.; Colis, S.; Schmerber, G.; Dinia, A.; Lassri, H.

    2016-07-01

    We investigate the magnetic and optical properties of Zn1-xFexO (x = 0, 0.03, 0.05, and 0.07) thin films grown by spray pyrolysis technique. The magnetization as a function of temperature [M (T)] shows a prevailing paramagnetic contribution at low temperature. By using spin wave theory, we separate the M (T) curve in two contributions: one showing intrinsic ferromagnetism and one showing a purely paramagnetic behavior. Furthermore, it is shown that the spin wave theory is consistent with ab-initio calculations only when oxygen vacancies are considered, highlighting the key role played by structural defects in the mechanism driving the observed ferromagnetism. Using UV-visible measurements, the transmittance, reflectance, band gap energy, band tail, dielectric coefficient, refractive index, and optical conductivity were extracted and related to the variation of the Fe content.

  17. New Techniques to Test Spin-Gravity Coupling with Atomic Clock

    NASA Technical Reports Server (NTRS)

    Maleki, L.

    2000-01-01

    Recent advances in laser technology have produced the opportunity to realize more stable and accurate atomic clocks, by laser excitation, manipulation and cooling of atoms. In this paper we will describe a new scheme based on the use of lasers with atomic clocks to increase the sensitivity of experimental search for a spin-gravity coupling.

  18. Study of Low Energy Electron Inelastic Scattering Mechanisms Using Spin Sensitive Techniques

    NASA Astrophysics Data System (ADS)

    Hsu, Hongbing

    1995-01-01

    Spin sensitive electron spectroscopies were used to study low energy electron inelastic scattering from metal surfaces and thin films. In these experiments, a beam of spin polarized electrons from a GaAs source is directed on the sample surface, and the spin polarization and intensity are measured as a function of energy loss and scattering angle by a Mott electron polarimeter coupled with a concentric hemispherical energy analyzer. Systematic studies of the angular dependence of inelastically scattered electrons were conducted on a Cu(100) surface, and Mo/Cu(100), non-magnetized Fe/Cu(100), and Co/Cu(100) films. The polarization and intensity of scattered electrons were measured as function of energy loss and scattering angle. Further studies were also conducted on Ag(100) surface and amorphous Cu/Ag(100) films. From the experimental results, the angular distributions of dipole and impact scattered electrons can be determined individually and both are found to peak in the specular scattering direction. Preliminary studies were conducted on magnetized Co/Cu(100) films. The spin dependent scattering intensity asymmetry was measured, with a clearly observable peak at energy loss of ~1 eV, which coincides with the band splitting. The polarizations of secondary electrons produced by an unpolarized primary beam were also measured. The polarizations can be related to the band polarization of magnetized cobalt films.

  19. Using non-invasive molecular spectroscopic techniques to detect unique aspects of protein Amide functional groups and chemical properties of modeled forage from different sourced-origins

    NASA Astrophysics Data System (ADS)

    Ji, Cuiying; Zhang, Xuewei; Yu, Peiqiang

    2016-03-01

    The non-invasive molecular spectroscopic technique-FT/IR is capable to detect the molecular structure spectral features that are associated with biological, nutritional and biodegradation functions. However, to date, few researches have been conducted to use these non-invasive molecular spectroscopic techniques to study forage internal protein structures associated with biodegradation and biological functions. The objectives of this study were to detect unique aspects and association of protein Amide functional groups in terms of protein Amide I and II spectral profiles and chemical properties in the alfalfa forage (Medicago sativa L.) from different sourced-origins. In this study, alfalfa hay with two different origins was used as modeled forage for molecular structure and chemical property study. In each forage origin, five to seven sources were analyzed. The molecular spectral profiles were determined using FT/IR non-invasive molecular spectroscopy. The parameters of protein spectral profiles included functional groups of Amide I, Amide II and Amide I to II ratio. The results show that the modeled forage Amide I and Amide II were centered at 1653 cm- 1 and 1545 cm- 1, respectively. The Amide I spectral height and area intensities were from 0.02 to 0.03 and 2.67 to 3.36 AI, respectively. The Amide II spectral height and area intensities were from 0.01 to 0.02 and 0.71 to 0.93 AI, respectively. The Amide I to II spectral peak height and area ratios were from 1.86 to 1.88 and 3.68 to 3.79, respectively. Our results show that the non-invasive molecular spectroscopic techniques are capable to detect forage internal protein structure features which are associated with forage chemical properties.

  20. Polycrystalline BiFeO3 thin film synthesized via sol-gel assisted spin coating technique for photosensitive application

    NASA Astrophysics Data System (ADS)

    Bogle, K. A.; Narwade, R. D.; Phatangare, A. B.; Dahiwale, S. S.; Mahabole, M. P.; Khairnar, R. S.

    2016-05-01

    We are reporting photosensitivity property of BiFeO3 thin film under optical illumination. The thin film used for photosensitivity work was fabricated via sol-gel assisted spin coating technique. I-V measurements on the Cu/BiFeO3/Al structure under dark condition show a good rectifying property and show dramatic blue shit in threshold voltage under optical illumination. The microstructure, morphology and elemental analysis of the films were characterized by using XRD, UV-Vis, FTIR, SEM and EDS.

  1. Structural and Spectroscopic Characterization of a High-Spin {FeNO}(6) Complex with an Iron(IV)-NO(-) Electronic Structure.

    PubMed

    Speelman, Amy L; Zhang, Bo; Krebs, Carsten; Lehnert, Nicolai

    2016-06-01

    Although the interaction of low-spin ferric complexes with nitric oxide has been well studied, examples of stable high-spin ferric nitrosyls (such as those that could be expected to form at typical non-heme iron sites in biology) are extremely rare. Using the TMG3 tren co-ligand, we have prepared a high-spin ferric NO adduct ({FeNO}(6) complex) via electrochemical or chemical oxidation of the corresponding high-spin ferrous NO {FeNO}(7) complex. The {FeNO}(6) compound is characterized by UV/Visible and IR spectroelectrochemistry, Mössbauer and NMR spectroscopy, X-ray crystallography, and DFT calculations. The data show that its electronic structure is best described as a high-spin iron(IV) center bound to a triplet NO(-) ligand with a very covalent iron-NO bond. This finding demonstrates that this high-spin iron nitrosyl compound undergoes iron-centered redox chemistry, leading to fundamentally different properties than corresponding low-spin compounds, which undergo NO-centered redox transformations. PMID:27101151

  2. Assessment of natural radioactivity and function of minerals in soils of Yelagiri hills, Tamilnadu, India by Gamma Ray spectroscopic and Fourier Transform Infrared (FTIR) techniques with statistical approach

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, A.; Ravisankar, R.; Rajalakshmi, A.; Eswaran, P.; Vijayagopal, P.; Venkatraman, B.

    2015-02-01

    Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearson's correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium.

  3. Assessment of natural radioactivity and function of minerals in soils of Yelagiri hills, Tamilnadu, India by Gamma Ray spectroscopic and Fourier Transform Infrared (FTIR) techniques with statistical approach.

    PubMed

    Chandrasekaran, A; Ravisankar, R; Rajalakshmi, A; Eswaran, P; Vijayagopal, P; Venkatraman, B

    2015-02-01

    Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearson's correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium. PMID:25467664

  4. Note: Electrical detection and quantification of spin rectification effect enabled by shorted microstrip transmission line technique

    SciTech Connect

    Soh, Wee Tee; Ong, C. K.; Peng, Bin; State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 ; Chai, Guozhi

    2014-02-15

    We describe a shorted microstrip method for the sensitive quantification of Spin Rectification Effect (SRE). SRE for a Permalloy (Ni{sub 80}Fe{sub 20}) thin film strip sputtered onto SiO{sub 2} substrate is demonstrated. Our method obviates the need for simultaneous lithographic patterning of the sample and transmission line, therefore greatly simplifying the SRE measurement process. Such a shorted microstrip method can allow different contributions to SRE (anisotropic magnetoresistance, Hall effect, and anomalous Hall effect) to be simultaneously determined. Furthermore, SRE signals from unpatterned 50 nm thick Permalloy films of area dimensions 5 mm × 10 mm can even be detected.

  5. Study of the effect of Cal-Red on the secondary structure of human serum albumin by spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Dong, Lijun; Chen, Xingguo; Hu, Zhide

    2007-11-01

    The effect of Cal-Red on the structure of human serum albumin (HSA) was studied using Resonance light scattering (RLS), Fourier transformed Infrared (FT-IR) and Circular dichroism (CD) spectroscopic methods. The RLS spectroscopic results show that the RLS intensity of HSA was significantly increased in the presence of Cal-Red. The binding parameters of HSA with Cal-Red were studied at different temperatures of 289, 299, 309 and 319 K at pH 4.1. It is indicated by the Scatchard plots that the binding constant K decreased from 4.03 × 10 8 to 7.59 × 10 7 l/mol and the maximum binding number N decreased from 215 to 152 with increasing the temperature, respectively. The binding process was exothermic and spontaneous, as indicated by the thermodynamic analyses, and the major part of the binding energy is hydrophobic interaction. The enthalpy change Δ H0, the free energy change Δ G0 and the entropy change Δ S0 of 289 K were calculated to be -42.75 kJ/mol, -47.56 kJ/mol and 16.66 J/mol K, respectively. The alterations of protein secondary structure in the presence of Cal-Red in aqueous solution were quantitatively calculated from FT-IR and CD spectroscopy with reductions of α-helices content about 5%, β-turn from 10% to 2% and with increases of β-sheet from 38% to 51%.

  6. Osmotically induced removal of water from fungal cells as determined by a spin probe technique.

    PubMed

    Miller, R W

    1978-11-01

    Effects of physical environment on plasma membrane semipermeability and osmotic induction of changes in aqueous cytoplasmic volume were studied in vegetative and spore cells of a plant pathogenic fungus, Fusarium sulphureum. A direct method, employing a spin probe molecule that partitioned between intracellular aqueous and hydrophobic phases, allowed measurement of reversible water movement out of macroconidial cells and chlamydospores exposed to solutions of high osmolarity. Equilibrium distribution of the spin probe between intracellular aqueous and lipid phases was more rapid than movement of water in and out of the cells. The extent of water removal was exponentially dependent on osmotic strength. Some cells became irreversibly permeable to divalent cations on treatment with sodium chloride above 1.5 osmolar but addition of sucrose to the suspension medium at equivalent osmolar concentrations caused water removal without adversely affecting the viability. Sucrose also protected the plasma membrane against damage during freeze-drying. Induction of plasma membrane damage by osmotic shock or freeze-drying permitted rapid permeation of nickel ions. Neither slow equilibration of intracellular components with divalent paramagnetic cations nor partial permeability of damaged plasma membranes to these ions was observed. PMID:16660597

  7. The origin, composition and history of cometary ices from spectroscopic studies

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.

    1989-01-01

    The spectroscopic analysis of pristine cometary material provides a very important probe of the chemical identity of the material as well as of the physical and chemical conditions which prevailed during the comet's history. Concerning classical spectroscopy, the spectral regions which will most likely prove most useful are the infrared, the visible and ultraviolet. Newer spectroscopic techniques which have the potential to provide equally important information include nuclear magnetic resonance (NMR) and electron spin resonance (ESR). Each technique is summarized with emphasis placed on the kind of information which can be obtained.

  8. Identification of vegetable oil botanical speciation in refined vegetable oil blends using an innovative combination of chromatographic and spectroscopic techniques.

    PubMed

    Osorio, Maria Teresa; Haughey, Simon A; Elliott, Christopher T; Koidis, Anastasios

    2015-12-15

    European Regulation 1169/2011 requires producers of foods that contain refined vegetable oils to label the oil types. A novel rapid and staged methodology has been developed for the first time to identify common oil species in oil blends. The qualitative method consists of a combination of a Fourier Transform Infrared (FTIR) spectroscopy to profile the oils and fatty acid chromatographic analysis to confirm the composition of the oils when required. Calibration models and specific classification criteria were developed and all data were fused into a simple decision-making system. The single lab validation of the method demonstrated the very good performance (96% correct classification, 100% specificity, 4% false positive rate). Only a small fraction of the samples needed to be confirmed with the majority of oils identified rapidly using only the spectroscopic procedure. The results demonstrate the huge potential of the methodology for a wide range of oil authenticity work. PMID:26190602

  9. Simple and highly sensitive measurement method for detection of glass transition temperatures of polymers: application of ESR power saturation phenomenon with conventional spin-probe technique.

    PubMed

    Miwa, Yohei; Yamamoto, Katsuhiro

    2012-08-01

    A combination of the microwave power saturation (MPS) method of electron spin resonance (ESR) and spin probing is proposed as a simple and practical technique for detecting the glass transition temperatures, T(g), of polymers with high sensitivity. Effects of the spin-probe size and concentration on the T(g) value of polystyrene (PS) determined by MPS, T(g,ESR), were first evaluated. Spin-probed PS with four types of nitroxides, namely, di-tert-butyl nitroxide (DBN), 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl (BZONO), and 4',4'-dimethyl-spiro(5α-cholestane-3,2'-oxazolidin)-3'-yloxy free radical (CHOL), having molecular weights of 144, 156, 276, and 473, respectively, and spin-labeled PS with TEMPO were prepared. The T(g,ESR) values for the spin-probed PS with DBN, TEMPO, BZONO, and CHOL and spin-labeled PS were determined to 360, 363, 374, 374, and 375 K, respectively, within experimental uncertainties of 2 K, whereas the glass transition temperature determined by DSC, T(g,DSC), was 375 K for all samples. A significant decrease in T(g,ESR) for small spin probes was shown to be due to decoupling between the mobilities of small spin probes and PS segments. Concerning the concentration, a decrease in the saturation factor, S, induced by shortening of the spin-spin relaxation time was observed for the spin-probed PS with CHOL when the concentration of CHOL was more than 1.0 wt %. Furthermore, T(g,ESR) decreased slightly with increasing weight fraction of CHOL because of the "plasticizer effect" of CHOL. However, the T(g,ESR) and T(g,DSC) values corresponded for each concentration. Thus, large spin probes, such as CHOL and BZONO, are appropriate for the determination of T(g,ESR) values; the concentration of the spin probes does not affect the T(g,ESR) value unless the overall T(g) value is reduced by blending of excess spin probes. Finally, measurements of T(g,ESR) in PS/silica composites containing more than 95 wt

  10. Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

    NASA Astrophysics Data System (ADS)

    Hayashida, H.; Oku, T.; Kira, H.; Sakai, K.; Hiroi, K.; Ino, T.; Shinohara, T.; Imagawa, T.; Ohkawara, M.; Ohoyama, K.; Kakurai, K.; Takeda, M.; Yamazaki, D.; Oikawa, K.; Harada, M.; Miyata, N.; Akutsu, K.; Mizusawa, M.; Parker, J. D.; Matsumoto, Y.; Zhang, S.; Suzuki, J.; Soyama, K.; Aizawa, K.; Arai, M.

    2016-04-01

    We have been developing a 3He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3He polarization reached 70% and was stable over one week. A demonstration of the 3He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively.

  11. Characterization of fine particulate matter in ambient air by combining TEM and multiple spectroscopic techniques--NMR, FTIR and Raman spectroscopy.

    PubMed

    Ji, Zhurun; Dai, Rucheng; Zhang, Zengming

    2015-03-01

    This paper reports a systematic study of the microstructures and spectroscopic characteristics of PM2.5 and its potential sources in Beijing by combining transmission electron microscopy and multiple spectroscopic techniques: nuclear magnetic resonance, Fourier transform infrared and Raman spectroscopy. TEM images showed that dominant components of PM2.5 are airborne organic substances with many trace metal elements which are associated with combustion sources. NMR spectra precisely determined the percentage of carbonaceous speciation in both PM2.5 (with spatial and temporal distribution) and its potential sources, and distinguished the similarities and differences among them. In FTIR spectra, a remarkable peak at 1390 cm(-1) that appeared only in PM2.5 samples was attributed to NH4NO3, representing the occurrence of secondary processes. Raman spectra revealed certain inorganic compounds including sulfate and nitrate ions. Based on the analysis of the decomposition of Raman spectra, spectral parameters provided structural information and helped to find potential sources of PM2.5. In the space of carbon aromaticity index and ID1/IG, PM2.5 points followed a linear distribution which may also be useful in source tracing. The result shows that the combined non-destructive methods are efficient to trace the sources of PM2.5. PMID:25597896

  12. A new membrane probing steroidal spin label: synthesis and applications.

    PubMed

    Katoch, R; Trivedi, G K; Phadke, R S

    2000-02-01

    The applicability of a new steroidal spin label, 3-oxo-androstan-17 beta-yl-(2",2",6",6"-tetramethyl-N-oxyl) piperidyl butan-1',4'-dioate, in studying the phase transition properties of model membrane L-alpha-dipalmitoyl phosphatidyl choline (DPPC) in the presence and absence of drugs has been explored. Its synthesis and characterization has been described herein. Besides, the localization of this spin label in lipid liposomes has been studied using electron spin resonance (ESR), differential scanning calorimetry (DSC) and 1H and 31P NMR spectroscopic techniques. The label has also been used to study the permeability of epinephrine into membrane. The results show that the spin label has a good potential as a spin probe in the study of biomembranes. PMID:10983412

  13. A Non-Invasive Thermal Drift Compensation Technique Applied to a Spin-Valve Magnetoresistive Current Sensor

    PubMed Central

    Moreno, Jaime Sánchez; Muñoz, Diego Ramírez; Cardoso, Susana; Berga, Silvia Casans; Antón, Asunción Edith Navarro; de Freitas, Paulo Jorge Peixeiro

    2011-01-01

    A compensation method for the sensitivity drift of a magnetoresistive (MR) Wheatstone bridge current sensor is proposed. The technique was carried out by placing a ruthenium temperature sensor and the MR sensor to be compensated inside a generalized impedance converter circuit (GIC). No internal modification of the sensor bridge arms is required so that the circuit is capable of compensating practical industrial sensors. The method is based on the temperature modulation of the current supplied to the bridge, which improves previous solutions based on constant current compensation. Experimental results are shown using a microfabricated spin-valve MR current sensor. The temperature compensation has been solved in the interval from 0 °C to 70 °C measuring currents from −10 A to +10 A. PMID:22163748

  14. Interfacial spectroscopic characterization of organic/ferromagnet hetero-junction of 3,4,9,10-perylene-teracarboxylic dianhydride-based organic spin valves

    NASA Astrophysics Data System (ADS)

    Hong, Jhen-Yong; Ou Yang, Kui-Hon; Wang, Bo-Yao; Li, Kai-Shin; Shiu, Hung-Wei; Chen, Chia-Hao; Chan, Yuet-Loy; Wei, Der-Hsin; Chang, Fan-Hsiu; Lin, Hong-Ji; Chiang, Wen-Chung; Lin, Minn-Tsong

    2014-02-01

    We report interfacial characterization of 3,4,9,10-perylene-teracarboxylic dianhydride (PTCDA)-based organic spin valves (OSV) dusted with a thin layer of partially oxidized alumina at the organic semiconductor (OSC)/ferromagnet (FM) interfaces. Up to 13.5% magnetoresistance is achieved at room temperature. X-ray photoelectron spectroscopy measurements reveal interfacial electronic interaction between PTCDA and FM while the application of a thin alumina layer at the PTCDA/FM interfaces prevents the electronic hybridization and effectively preserves the spin injection into the OSC spacer. This finding demonstrates the critical effect of interfacial structure on magnetotransport behavior in OSV.

  15. Investigation on the interaction between isorhamnetin and bovine liver catalase by spectroscopic techniques under different pH conditions.

    PubMed

    Yang, Yumin; Li, Daojin

    2016-08-01

    The binding of isorhamnetin to bovine liver catalase (BLC) was first investigated at 302, 310 and 318 K at pH 7.4 using spectroscopic methods including fluorescence spectra, circular dichroism (CD) and UV-vis absorption. Spectrophotometric observations are rationalized mainly in terms of a static quenching process. The binding constants and binding sites were evaluated by fluorescence quenching methods. Enzymatic activity of BLC in the absence and presence of isorhamnetin was measured using a UV/vis spectrophotometer. The result revealed that the binding of isorhamnetin to BLC led to a reduction in the activity of BLC. The positive entropy change and enthalpy change indicated that the interaction of isorhamnetin with BLC was mainly driven by hydrophobic forces. The distance r between the donor (BLC) and acceptor (isorhamnetin) was estimated to be 2.99 nm according to fluorescence resonance energy transfer. Fluorescence, synchronous fluorescence, and CD spectra showed no obvious change in the conformation of BLC upon the binding of isorhamnetin. In addition, the influence of pH on the binding of isorhamnetin to BLC was investigated and the binding ability of the drug to BLC deceased under other pH conditions (pH 9.0, 6.5, 5.0, 3.5, or 2.0) as compared with that at pH 7.4. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26748824

  16. Ellipsometric and Raman spectroscopic study of nanocrystalline silicon thin films prepared by a rf magnetron sputtering technique

    NASA Astrophysics Data System (ADS)

    Bouizem, Y.; Abbes, C.; Sib, J. D.; Benlakehal, D.; Baghdad, R.; Chahed, L.; Zellama, K.; Charvet, S.

    2008-11-01

    The structure of nanocrystalline silicon thin films (nc-Si:H) deposited by rf magnetron sputtering of a high-purity crystalline silicon target using argon (30%) and hydrogen (70%) gas mixture, under different pressures (P = 2, 3 and 4 Pa) and different substrate temperature (Ts = 100, 150 and 200 °C), has been studied with spectroscopic ellipsometry (SE; 1.5-5 eV) complemented with Raman spectroscopy measurements. The ellipsometry data were carefully analyzed using the Brüggeman effective medium approximation and the Tauc-Lorentz model. The results of this investigation clearly show that the samples deposited at 2 Pa present a completely amorphous structure whatever the substrate temperature, while those deposited at 3 and 4 Pa exhibit a nanocrystalline structure. These results suggest the existence of a threshold pressure around 3 Pa for which crystallization occurs. The samples are well crystallized with a crystalline volume fraction ranging from about 60 to 90%, and exhibit a mixture of small and large crystallite sizes. The deposition temperature has practically no effect on the size of the crystallites and on the average crystalline volume fractions. These results are in good agreement with the Raman spectroscopy data, and suggest the formation of Si crystallites in the gas phase. The analysis of the ellipsometric spectra also shows that the bulk layer is initiated from an amorphous interface (a-Si:H) present in the first steps of the growth, and is followed by a less crystallized subsurface layer.

  17. Determination of photocarrier density under continuous photoirradiation using spectroscopic techniques as applied to polymer: Fullerene blend films

    SciTech Connect

    Kanemoto, Katsuichi Nakatani, Hitomi; Domoto, Shinya

    2014-10-28

    We propose a method to determine the density of photocarrier under continuous photoirradiation in conjugated polymers using spectroscopic signals obtained by photoinduced absorption (PIA) measurements. The bleaching signals in the PIA measurements of polymer films and the steady-state absorption signals of oxidized polymer solution are employed to determine the photocarrier density. The method is applied to photocarriers of poly (3-hexylthiophene) (P3HT) in a blended film consisting of P3HT and [6,6]-phenyl C61 butyric acid methyl ester (PCBM). The photocarrier density under continuous photoirradiation of 580 mW/cm{sup 2} is determined to be 3.5 × 10{sup 16 }cm{sup −3}. Using a trend of the carrier density increasing in proportion to the square root of photo-excitation intensity, we provide a general formula to estimate the photocarrier density under simulated 1 sun solar irradiation for the P3HT: PCBM film of an arbitrary thickness. We emphasize that the method proposed in this study enables an estimate of carrier density without measuring a current and can be applied to films with no electrodes as well as to devices.

  18. Anomaly Detection Techniques with Real Test Data from a Spinning Turbine Engine-Like Rotor

    NASA Technical Reports Server (NTRS)

    Abdul-Aziz, Ali; Woike, Mark R.; Oza, Nikunj C.; Matthews, Bryan L.

    2012-01-01

    Online detection techniques to monitor the health of rotating engine components are becoming increasingly attractive to aircraft engine manufacturers in order to increase safety of operation and lower maintenance costs. Health monitoring remains a challenge to easily implement, especially in the presence of scattered loading conditions, crack size, component geometry, and materials properties. The current trend, however, is to utilize noninvasive types of health monitoring or nondestructive techniques to detect hidden flaws and mini-cracks before any catastrophic event occurs. These techniques go further to evaluate material discontinuities and other anomalies that have grown to the level of critical defects that can lead to failure. Generally, health monitoring is highly dependent on sensor systems capable of performing in various engine environmental conditions and able to transmit a signal upon a predetermined crack length, while acting in a neutral form upon the overall performance of the engine system.

  19. Structural analysis of complexes formed by ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate with Ni(II), Zn(II) and Cd(II) through spectroscopic and DFT techniques

    NASA Astrophysics Data System (ADS)

    Prakash, Om; Gautam, Priyanka; Dani, R. K.; Nandi, Abhisikta; Singh, N. K.; Singh, Ranjan K.

    2014-04-01

    A piperazine derivative, ethyl 4-phenylthiocarbamoyl piperazine-1-carboxylate and its Ni(II), Zn(II) and Cd(II) complexes have been synthesized and characterized by elemental analyses, magnetic susceptibility measurement, UV-Visible, FTIR, Raman spectroscopic and DFT methods. The Ni(II) and Zn(II) bind through the N and S sites of the two ligand Heptpc and N site of two pyridine molecules. However, the Cd(II) binds through the only N sites of the two ligand Heptpc and N site of two pyridine molecules. On the basis of various techniques used for the characterizations of the complexes, we found that the most possible geometry of the Ni(II) and Zn(II) complexes are distorted octahedral and of the Cd(II) complex is distorted tetrahedral.

  20. Multidisciplinary approach for the study of an Egyptian coffin (late 22nd/early 25th dynasty): combining imaging and spectroscopic techniques.

    PubMed

    Bracci, S; Caruso, O; Galeotti, M; Iannaccone, R; Magrini, D; Picchi, D; Pinna, D; Porcinai, S

    2015-06-15

    This paper demonstrates that an educated methodology based on both non-invasive and micro invasive techniques in a two-step approach is a powerful tool to characterize the materials and stratigraphies of an Egyptian coffin, which was restored several times. This coffin, belonging to a certain Mesiset, is now located at the Museo Civico Archeologico of Bologna (inventory number MCABo EG 1963). Scholars attributed it to the late 22nd/early 25th dynasty by stylistic comparison. The first step of the diagnostic approach applied imaging techniques on the whole surface in order to select measurements spots and to unveil both original and restored areas. Images and close microscopic examination of the polychrome surface allowed selecting representative areas to be investigated in situ by portable spectroscopic techniques: X-ray Fluorescence (XRF), Fiber Optic Reflectance Spectroscopy (FORS) and Fourier Transform Infrared spectroscopy (FTIR). After the analysis of the results coming from the first step, very few selected samples were taken to clarify the stratigraphy of the polychrome layers. The first step, based on the combination of imaging and spectroscopic techniques in a totally non-invasive modality, is quite unique in the literature on Egyptian coffins and enabled us to reveal many differences in the ground layer's composition and to identify a remarkable number of pigments in the original and restored areas. This work offered also a chance to check the limitations of the non-invasive approach applied on a complex case, namely the right localization of different materials in the stratigraphy and the identification of binding media. Indeed, to dissolve any remaining doubts on superimposed layers belonging to different interventions, it was necessary to sample few micro-fragments in some selected areas and analyze them prepared as cross-sections. The original ground layer is made of calcite, while the restored areas show the presence of either a mixture of calcite

  1. Multidisciplinary approach for the study of an Egyptian coffin (late 22nd/early 25th dynasty): Combining imaging and spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Bracci, S.; Caruso, O.; Galeotti, M.; Iannaccone, R.; Magrini, D.; Picchi, D.; Pinna, D.; Porcinai, S.

    2015-06-01

    This paper demonstrates that an educated methodology based on both non-invasive and micro invasive techniques in a two-step approach is a powerful tool to characterize the materials and stratigraphies of an Egyptian coffin, which was restored several times. This coffin, belonging to a certain Mesiset, is now located at the Museo Civico Archeologico of Bologna (inventory number MCABo EG 1963). Scholars attributed it to the late 22nd/early 25th dynasty by stylistic comparison. The first step of the diagnostic approach applied imaging techniques on the whole surface in order to select measurements spots and to unveil both original and restored areas. Images and close microscopic examination of the polychrome surface allowed selecting representative areas to be investigated in situ by portable spectroscopic techniques: X-ray Fluorescence (XRF), Fiber Optic Reflectance Spectroscopy (FORS) and Fourier Transform Infrared spectroscopy (FTIR). After the analysis of the results coming from the first step, very few selected samples were taken to clarify the stratigraphy of the polychrome layers. The first step, based on the combination of imaging and spectroscopic techniques in a totally non-invasive modality, is quite unique in the literature on Egyptian coffins and enabled us to reveal many differences in the ground layer's composition and to identify a remarkable number of pigments in the original and restored areas. This work offered also a chance to check the limitations of the non-invasive approach applied on a complex case, namely the right localization of different materials in the stratigraphy and the identification of binding media. Indeed, to dissolve any remaining doubts on superimposed layers belonging to different interventions, it was necessary to sample few micro-fragments in some selected areas and analyze them prepared as cross-sections. The original ground layer is made of calcite, while the restored areas show the presence of either a mixture of calcite

  2. A homonuclear spin-pair filter for solid-state NMR based on adiabatic-passage techniques

    NASA Astrophysics Data System (ADS)

    Verel, René; Baldus, Marc; Ernst, Matthias; Meier, Beat H.

    1998-05-01

    A filtering scheme for the selection of spin pairs (and larger spin clusters) under fast magic-angle spinning is proposed. The scheme exploits the avoided level crossing in spin pairs during an adiabatic amplitude sweep through the so-called HORROR recoupling condition. The advantages over presently used double-quantum filters are twofold. (i) The maximum theoretical filter efficiency is, due to the adiabatic variation, 100% instead of 73% as for transient methods. (ii) Since the filter does not rely on the phase-cycling properties of the double-quantum coherence, there is no need to obtain the full double-quantum intensity for all spins in the sample at one single point in time. The only important requirement is that all coupled spins pass through a two-spin state during the amplitude sweep. This makes the pulse scheme robust with respect to rf-amplitude missetting, rf-field inhomogeneity and chemical-shift offset.

  3. Study of the plasma surface interactions by the "spinning wall" technique

    NASA Astrophysics Data System (ADS)

    Guha, Joydeep

    For the past few decades plasma etching has emerged as a dominant processing step in integrated-circuit (IC) device manufacturing. Due to the presence of reactive radicals and ions, plasmas are rich in chemistry and are widely used to etch sub-micron size features with complete fidelity. Radicals such as Cl, F, O etc. are the active species in the plasma that reacts with the material in the presence of ions forming volatile products, which leads to material removal. However, in these low pressure plasmas the radicals are lost to the reactor walls, which affect their number densities in the plasma. An important parameter to quantify radical loss at the surface is the recombination coefficient, gamma, defined as the probability per collision with the surface that an impinging radical will recombine. The surface in contact with the plasma interacts with the radicals, neutrals, ions, electrons, photons etc., which makes the measurement of kinetic parameter like the atom recombination probability a real challenge. A new technique has been developed to study the plasma-surface interactions in-situ. In this technique a cylindrical substrate is rapidly rotated between the plasma and differentially pumped diagnostic chambers, allowing portions of the surface to be periodically exposed to the plasma and then analyzed by desorption mass spectrometry and Auger electron spectroscopy. The time elapsed between the plasma exposure and subsequent analysis is controlled by varying the rotation frequency of the substrate. Using this technique Langmuir-Hinshelwood atom recombination probabilities have been measured in O2, Cl2, O2/Cl 2, Cl2/Ar and O2/Ar plasmas. A variety of diagnostic techniques have been used to analyze the plasmas. The gas temperature ( Tg) was measured by adding a trace amount of N2 (5%) to the plasma and measuring the emission of the N2 second positive system C 3piu, nu' → B 3pig, nu'' in the ultraviolet region. The electron densities (ne) were measured using a

  4. Structural aspects in self-assembled systems of polyoxyethylene surfactants, as studied by the spin probe technique

    NASA Astrophysics Data System (ADS)

    Caldararu, Horia

    1998-12-01

    Typical examples of structural characterization of self-assembled systems by the spin probes technique, selected from our representative results accumulated in the last years of systematic studies, are presented. The choice of the examples has aimed at emphasizing the potentiality of this technique in the study of self-assembled systems, in general, and of those of PEO surfactants, in particular. By using specific ESR parameters (the nitrogen hyperfine splitting (hfs), aN, the rotational correlation time, τc, the order parameter, S) of a variety of properly chosen nitroxides, problems such hydration degree and profile of the PEO chains, ordering and order profile along these chains, their penetrability by the oil solvent, role of the terminal OH in the micellization, as well as differences in these quantities vs . the nature of the aggregate (micelle, reverse micelle, lamellar phase, etc.), nature of the surfactants (conventional or triblock copolymer), solubilizates (water in reverse micelles or various alcohols in micelles) and temperature have been discussed.

  5. Combining spectroscopic data in the forensic analysis of paint: Application of a multiblock technique as chemometric tool.

    PubMed

    Lambert, Danny; Muehlethaler, Cyril; Esseiva, Pierre; Massonnet, Geneviève

    2016-06-01

    A study (Muehlethaler et al. [9]) has demonstrated the application of chemometrics for the analysis of domestic red paints. The paints have been analyzed with IR and Raman spectroscopies. As a result of these analyses, exploratory techniques, such as principal component analysis (PCA) and hierarchical clusters analysis (HCA) have been applied to both IR and Raman spectra. This allowed to observe the structure of the data among those red paints, and infer potential groups among them and to propose a classification model based on their chemical composition. IR spectroscopy showed group patterns related mainly to the binder and extender composition of the paints, whereas Raman spectroscopy data were mainly related to the pigment composition. The aim of the present study is to evaluate the potential of a Multiblock algorithm applied to the same data set. The concept of Multiblock, as a chemometric tool, is to combine data from several different analytical techniques in order to visualize most of the information at once. IR and Raman spectroscopy are then considered as "blocks" of data of the same dataset. One algorithm called common component and specific weight analysis (CCSWA) has been used in order to produce independent PCAs for each block, and the combined (common) information in a score plot. The results of this study showed group patterns of the analyzed paints, related to both binder and pigment compositions in one single score plot. Moreover, the number of groups observed with the multiblock representation (20 groups) is higher than independent PCAs projections (12 and 7 groups for IR and Raman respectively). This new application of chemometrics showed a great potential in forensic science, as practitioners often use a combination of several analytical techniques in order to characterize samples. This could be helpful when multiple and complementary analytical techniques are used in order to characterize and compare paint samples. PMID:27060443

  6. Evaluation of structure-reactivity descriptors and biological activity spectra of 4-(6-methoxy-2-naphthyl)-2-butanone using spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Agrawal, Megha; Deval, Vipin; Gupta, Archana; Sangala, Bagvanth Reddy; Prabhu, S. S.

    2016-10-01

    The structure and several spectroscopic features along with reactivity parameters of the compound 4-(6-methoxy-2-naphthyl)-2-butanone (Nabumetone) have been studied using experimental techniques and tools derived from quantum chemical calculations. Structure optimization is followed by force field calculations based on density functional theory (DFT) at the B3LYP/6-311++G(d,p) level of theory. The vibrational spectra have been interpreted with the aid of normal coordinate analysis. UV-visible spectrum and the effect of solvent have been discussed. The electronic properties such as HOMO and LUMO energies have been determined by TD-DFT approach. In order to understand various aspects of pharmacological sciences several new chemical reactivity descriptors - chemical potential, global hardness and electrophilicity have been evaluated. Local reactivity descriptors - Fukui functions and local softnesses have also been calculated to find out the reactive sites within molecule. Aqueous solubility and lipophilicity have been calculated which are crucial for estimating transport properties of organic molecules in drug development. Estimation of biological effects, toxic/side effects has been made on the basis of prediction of activity spectra for substances (PASS) prediction results and their analysis by Pharma Expert software. Using the THz-TDS technique, the frequency-dependent absorptions of NBM have been measured in the frequency range up to 3 THz.

  7. Evaluation of structure-reactivity descriptors and biological activity spectra of 4-(6-methoxy-2-naphthyl)-2-butanone using spectroscopic techniques.

    PubMed

    Agrawal, Megha; Deval, Vipin; Gupta, Archana; Sangala, Bagvanth Reddy; Prabhu, S S

    2016-10-01

    The structure and several spectroscopic features along with reactivity parameters of the compound 4-(6-methoxy-2-naphthyl)-2-butanone (Nabumetone) have been studied using experimental techniques and tools derived from quantum chemical calculations. Structure optimization is followed by force field calculations based on density functional theory (DFT) at the B3LYP/6-311++G(d,p) level of theory. The vibrational spectra have been interpreted with the aid of normal coordinate analysis. UV-visible spectrum and the effect of solvent have been discussed. The electronic properties such as HOMO and LUMO energies have been determined by TD-DFT approach. In order to understand various aspects of pharmacological sciences several new chemical reactivity descriptors - chemical potential, global hardness and electrophilicity have been evaluated. Local reactivity descriptors - Fukui functions and local softnesses have also been calculated to find out the reactive sites within molecule. Aqueous solubility and lipophilicity have been calculated which are crucial for estimating transport properties of organic molecules in drug development. Estimation of biological effects, toxic/side effects has been made on the basis of prediction of activity spectra for substances (PASS) prediction results and their analysis by Pharma Expert software. Using the THz-TDS technique, the frequency-dependent absorptions of NBM have been measured in the frequency range up to 3THz. PMID:27284764

  8. Optical monitoring of volcanic sulphur dioxide emissions—comparison between four different remote-sensing spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Weibring, P.; Swartling, J.; Edner, H.; Svanberg, S.; Caltabiano, T.; Condarelli, D.; Cecchi, G.; Pantani, L.

    2002-02-01

    The emissions of sulphur dioxide from the Italian volcanoes Mt. Etna and Stromboli were studied in ship-borne underpasses of their plumes. Four different optical spectroscopy techniques were used and inter-compared. All techniques utilise the absorption signature of the gas in the wavelength region of around 300 nm. A differential absorption lidar was employed in active gas concentration assessment. In parallel, a differential optical absorption spectroscopy system (DOAS) provided spectrally resolved absorption spectra. In one configuration the DOAS used a vertically looking telescope and the absorption of the sky-light was studied, while a different DOAS implementation utilised the sun disc as the light source in slant-angle, long-path absorption measurements. Parallel measurements with the customary correlation spectroscopy method were also performed. Path length Monte Carlo simulations of the down-welling radiation through the volcanic plume at different sun altitude and azimuth angles have been performed taking into account also the effects of other geometric parameters as the plume height and extension. The results are discussed with special emphasis on systematic effects due to scattering.

  9. Potential of spectroscopic techniques and chemometric analysis for rapid measurement of docosahexaenoic acid and eicosapentaenoic acid in algal oil.

    PubMed

    Wu, Di; He, Yong

    2014-09-01

    Developing rapid methods for measuring long-chain ω-3 (n-3) poly-unsaturated fatty acid (LCPUFA) contents has been a crucial request from the algal oil industry. In this study, four spectroscopy techniques, namely visible and short-wave near infra-red (Vis-SNIR), long-wave near infra-red (LNIR), mid-infra-red (MIR) and nuclear magnetic resonance (NMR) spectroscopy, were exploited for determining the docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) contents in algal oil. The best prediction for both DHA and EPA were achieved by NMR spectroscopy, in which the determination coefficients of cross-validation (rCV(2)) values were 0.963 and 0.967 for two LCPUFAs. The performances of Vis-SNIR and LNIR spectroscopy were also accepted. The variable selection was proved as an efficient and necessary step for the spectral analysis in this study. The results were promising and implied that spectroscopy techniques have a great potential for assessment of DHA and EPA in algal oil. PMID:24731319

  10. Intercomparison of HONO Measurements Made Using Wet-Chemical (NITROMAC) and Spectroscopic (IBBCEAS & LP/FAGE) Techniques

    NASA Astrophysics Data System (ADS)

    Dusanter, S.; Lew, M.; Bottorff, B.; Bechara, J.; Mielke, L. H.; Berke, A.; Raff, J. D.; Stevens, P. S.; Afif, C.

    2013-12-01

    A good understanding of the oxidative capacity of the atmosphere is important to tackle fundamental issues related to climate change and air quality. The hydroxyl radical (OH) is the dominant oxidant in the daytime troposphere and an accurate description of its sources in atmospheric models is of utmost importance. Recent field studies indicate higher-than-expected concentrations of HONO during the daytime, suggesting that the photolysis of HONO may be an important underestimated source of OH. Understanding the tropospheric HONO budget requires confidence in analytical instrumentation capable of selectively measuring HONO. In this presentation, we discuss an intercomparison study of HONO measurements performed during summer 2013 at the edge of a hardwood forest in Southern Indiana. This exercise involved a wet chemical technique (NITROMAC), an Incoherent Broad-Band Cavity Enhanced Absorption Spectroscopy instrument (IBBCEAS), and a Laser-Photofragmentation/Fluorescence Assay by Gas Expansion instrument (LP/FAGE). The agreement observed between the three techniques will be discussed for both ambient measurements and cross calibration experiments.

  11. Coupled micro-scale magnetic and spectroscopic techniques to understand the petrogenesis of iron sulfides in sedimentary rocks

    NASA Astrophysics Data System (ADS)

    Slotznick, S. P.; Webb, S. M.; Johnson, J. E.; Kirschvink, J. L.; Fischer, W. W.

    2013-12-01

    Paleomagnetism in sedimentary rocks containing iron sulfide mineral phases is challenging due to questions about the timing of formation, the potential for multiple-stages of iron sulfide growth, and their metastabilty in nature and in the laboratory. Bulk rock magnetic techniques have been developed and applied to identify and characterize ferromagnetic iron sulfides in a wide array of rock types from the geologic record (including some containing stable ChRM), but petrographic textural observations are required to inform the timing of their mineralization in any given sample. The solid-solution of pyrite/pyrrhotite/troilite and intimate intergrowth patterns of iron sulfides is difficult to untangle with standard light and electron microscopy. Here we report the development and application of a complementary set of techniques designed to inform and untangle the history and processes involved in the mineralization of sulfur-bearing minerals in sedimentary rocks. X-ray absorption spectroscopy of the S K-edge provides insight into the chemistry (such as valence state, electronic structure, type of neighbors) of sulfur-bearing solids. We used a new synchrotron-based X-ray microprobe developed at SSRL to measure, distinguish, and then image sulfur phases via multiple energy maps at micron scales. From these maps we can quantitatively differentiate a wide range of sulfur-bearing phases in polished thin sections, such as pyrrhotite, pyrite, and greigite, and ordinate them into a petrogenic scheme. At a similar scale, using SQUID microscopy allows us to identify and map the presence and field strength of ferromagnetic minerals within a sample. Combined with bulk rock magnetic techniques, these two micro-scale methods pair well to confirm textural observations, beyond those already noted using optical and scanning electron microscopy. Here we will present work from a study of middle Proterozoic age sedimentary rocks from the Belt Supergroup, MT. By collecting a wide array

  12. Observational and laboratory studies of optical properties of black and brown carbon particles in the atmosphere using spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Nakayama, Tomoki; Matsumi, Yutaka

    2015-04-01

    Light absorption and scattering by aerosols are as an important contributor to radiation balance in the atmosphere. Black carbon (BC) is considered to be the most potent light absorbing material in the visible region of the spectrum, although light absorbing organic carbon (brown carbon or BrC) and mineral dust may also act as sources of significant absorption, especially in the ultraviolet (UV) and shorter visible wavelength regions. The optical properties of such particles depend on wavelength, particle size and shape, morphology, coating, and complex refractive index (or chemical composition), and therefore accurate in situ measurements of the wavelength dependence of the optical properties of particles are needed. Recently, cavity ring-down spectroscopy (CRDS) and photoacoustic spectroscopy (PAS) have been used for the direct measurements of extinction and absorption coefficients of particles suspended in air. We have applied these techniques to the observational studies of optical properties of BC and BrC in an urban site in Japan and to the laboratory studies of optical properties of secondary organic aerosols (SOAs) generated from a variety of biogenic and anthropogenic volatile organic compounds and those of diesel exhaust particles (DEPs). In the presentation, the basic principles of these techniques and the results obtained in our studies and in the recent literatures will be overviewed. References Guo, X. et al., Measurement of the light absorbing properties of diesel exhaust particles using a three-wavelength photoacoustic spectrometer, Atmos. Environ., 94, 428-437 (2014). Nakayama, T. et al., Measurements of aerosol optical properties in central Tokyo during summertime using cavity ring-down spectroscopy: Comparison with conventional techniques, Atmos. Environ., 44, 3034-3042 (2010). Nakayama, T. et al., Laboratory studies on optical properties of secondary organic aerosols generated during the photooxidation of toluene and the ozonolysis of alpha

  13. Development of synchrotron x-ray micro-spectroscopic techniques and application to problems in low temperature geochemistry. Progress report

    SciTech Connect

    Not Available

    1993-10-01

    The focus of the technical development effort has been the development of apparatus and techniques for the utilization of X-ray Fluorescence (XRF), Extended X-ray Absorption Fine Structure (EXAFS) and X-ray Absorption Near Edge Structure (XANES) spectroscopies in a microprobe mode. The present XRM uses white synchrotron radiation (3 to 30 keV) from a bending magnet for trace element analyses using the x-ray fluorescence technique Two significant improvements to this device have been recently implemented. Focusing Mirror: An 8:1 ellipsoidal mirror was installed in the X26A beamline to focus the incident synchrotron radiation and thereby increase the flux on the sample by about a factor of 30. Incident Beam Monochromator: The monochromator has been successfully installed and commissioned in the X26A beamline upstream of the mirror to permit analyses with focused monochromatic radiation. The monochromator consists of a channel-cut silicon (111) crystal driven by a Klinger stepping motor translator. We have demonstrated the operating range of this instrument is 4 and 20 keV with 0.01 eV steps and produces a beam with a {approximately}10{sup {minus}4} energy bandwidth. The primary purpose of the monochromator is for x-ray absorption spectroscopy (XAS) measurements but it is also used for selective excitation in trace element microanalysis. To date, we have conducted XANES studies on Ti, Cr, Fe, Ce and U, spanning the entire accessible energy range and including both K and L edge spectra. Practical detection limits for microXANES are 10--100 ppM for 100 {mu}m spots.

  14. Precise oxygen and hydrogen isotope determination in nanoliter quantities of speleothem inclusion water by cavity ring-down spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Uemura, Ryu; Nakamoto, Masashi; Asami, Ryuji; Mishima, Satoru; Gibo, Masakazu; Masaka, Kosuke; Jin-Ping, Chen; Wu, Chung-Che; Chang, Yu-Wei; Shen, Chuan-Chou

    2016-01-01

    Speleothem inclusion-water isotope compositions are a promising new climatic proxy, but their applicability is limited by their low content in water and by analytical challenges. We have developed a precise and accurate isotopic technique that is based on cavity ring-down spectroscopy (CRDS). This method features a newly developed crushing apparatus, a refined sample extraction line, careful evaluation of the water/carbonate adsorption effect. After crushing chipped speleothem in a newly-developed crushing device, released inclusion water is purified and mixed with a limited amount of nitrogen gas in the extraction line for CRDS measurement. We have measured 50-260 nL of inclusion water from 77 to 286 mg of stalagmite deposits sampled from Gyokusen Cave, Okinawa Island, Japan. The small sample size requirement demonstrates that our analytical technique can offer high-resolution inclusion water-based paleoclimate reconstructions. The 1σ reproducibility for different stalagmites ranges from ±0.05 to 0.61‰ for δ18O and ±0.0 to 2.9‰ for δD. The δD vs. δ18O plot for inclusion water from modern stalagmites is consistent with the local meteoric water line. The 1000 ln α values based on calcite and fluid inclusion measurements from decades-old stalagmites are in agreement with the data from present-day farmed calcite experiment. Combination of coeval carbonate and fluid inclusion data suggests that past temperatures at 9-10 thousand years ago (ka) and 26 ka were 3.4 ± 0.7 °C and 8.2 ± 2.4 °C colder than at present, respectively.

  15. Traveling surface spin-wave resonance spectroscopy using surface acoustic waves

    NASA Astrophysics Data System (ADS)

    Gowtham, P. G.; Moriyama, T.; Ralph, D. C.; Buhrman, R. A.

    2015-12-01

    Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a piezoelectric crystal can, via the magnetoelastic interaction, resonantly excite traveling surface spin waves in an adjacent thin-film ferromagnet. These excited surface spin waves, traveling with a definite in-plane wave-vector q ∥ enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors, | q ∥ | = 2.5 × 104-8 × 104 cm-1, over which anisotropic dipolar interactions vary from being negligible to quite significant.

  16. Bi-nanoparticle (CdTe and CdSe) mixed polyaniline hybrid thin films prepared using spin coating technique

    NASA Astrophysics Data System (ADS)

    Verma, Deepak; Dutta, V.

    2009-02-01

    Polyaniline (Pani) films containing CdTe, CdSe, and both nanoparticles were deposited using spin coating technique. Pani was chemically synthesized by oxidation method, whereas surfactant free CdTe and CdSe nanoparticles were prepared using solvothermal method. Binanoparticle films showed an increase in the absorption from 350 nm to the near IR region. Absorption spectra also showed charge transfer complex formation for the binanoparticle hybrid thin films prepared with weight ratio of [Pani (camphor sulfonic acid, CSA):CdTe:CdSe] 200:100:75. Photoluminescence measurement for the bi-nanoparticle hybrid thin films confirmed that the required dissociation of excitons was taking place at the interface. Scanning electron microscopy images showed homogeneity and an interconnected network on the surface of the films prepared with Pani (CSA):CdTe:CdSe weight ratios of 200:100:50 and 200:100:75, respectively. Cyclic voltammetry confirmed better stability for the bi-nanoparticle hybrid films in comparison to Pani film. It also established the process of electrochemical charge transfer between the nanoparticles and the polymer matrix.

  17. Electrical and optical properties of p-type codoped ZnO thin films prepared by spin coating technique

    NASA Astrophysics Data System (ADS)

    Pathak, Trilok Kumar; Kumar, Vinod; Swart, H. C.; Purohit, L. P.

    2016-03-01

    Undoped, doped and codoped ZnO thin films were synthesized on glass substrates using a spin coating technique. Zinc acetate dihydrate, ammonium acetate and aluminum nitrate were used as precursor for zinc, nitrogen and aluminum, respectively. X-ray diffraction shows that the thin films have a hexagonal wurtzite structure for the undoped, doped and co-doped ZnO. The transmittance of the films was above 80% and the band gap of the film varied from 3.20 eV to 3.24 eV for undoped and doped ZnO. An energy band diagram to describe the photoluminescence from the thin films was also constructed. This diagram includes the various defect levels and possible quasi-Fermi levels. A minimum resistivity of 0.0834 Ω-cm was obtained for the N and Al codoped ZnO thin films with p-type carrier conductivity. These ZnO films can be used as a window layer in solar cells and in UV lasers.

  18. Thermoelectric properties of Si/SiB3 sub-micro composite prepared by melt-spinning technique

    NASA Astrophysics Data System (ADS)

    Xie, Jun; Ohishi, Yuji; Miyazaki, Yoshinobu; Yusufu, Aikebaier; Muta, Hiroaki; Kurosaki, Ken; Yamanaka, Shinsuke

    2015-08-01

    This study presents a new self-assembly process to form a fine structure in bulk Si. We fabricated a semiconducting composite material consisting of sub-micro-sized (100-500 nm) SiB3 precipitates distributed in a Si matrix whose grain size was on the order of microns. The sub-micro-sized SiB3 particles were precipitated during the spark plasma sintering process of a metastable Si-B (Si:B = 92:8) supersaturated solid solution prepared by the melt-spinning technique. The composite was a heavily doped (5 × 1020 cm-3) p-type semiconductor. The SiB3 precipitates did not affect the Seebeck coefficient, slightly reduced the carrier mobility, and greatly reduced the lattice thermal conductivity. Specifically, the lattice thermal conductivity was reduced by 44% compared with that of p-type Si without precipitates at room temperature. The SiB3 precipitates improved the thermoelectric figure of merit ZT from 0.17 to 0.23 at 1073 K, which indicates that the formation of small precipitates effectively improves the thermoelectric performance of Si-based thermoelectric materials.

  19. Use of radiocarbon and spectroscopic analyses to characterise soil organic matter pools isolated using different fractionation techniques.

    NASA Astrophysics Data System (ADS)

    Miller, Gemma; Cloy, Joanna; Garnett, Mark; Sohi, Saran; Rees, Robert; Griffiths, Bryan

    2015-04-01

    Experimental division of soil organic matter (SOM) into functional pools has the potential to improve soil C modelling. Soil physical fractionation techniques seek to quantify these pools, however the fractions isolated vary in number, size, ecological role and composition. The use of different techniques to quantify soil C fractions in different studies presents a question - do similar fractions isolated by different methods fit the same conceptual definition? This study examined a sandy loam from the south-west of Scotland, sampled in summer, which had been under grassland management for at least 20 years. We compared average 14C ages of SOM fractions isolated using three published and frequently applied physical fractionation methods (1) a density separation technique isolating three fractions - free light (FLF) < 1.8 cm 3, intra-aggregate light (IALF) < 1.8 cm-3 after aggregate disruption, and organo-mineral (O-min) > 1.8 g cm 3 (Sohi et al, 2001); (2) a combined physical and chemical separation isolating five fractions: sand and aggregates (S+A) > 63 µm and > 1.8 g cm-3, particulate organic matter (POM) > 63 µm and < 1.8 g cm 3, silt and clay (s+c) < 63 but > 45 µm, residual organic carbon (rSOC) the residue left after s+c is oxidised with NaOCl, and dissolved organic carbon (DOC) < 45 µm (Zimmermann et al, 2007); and (3) a hot water extraction method isolating two fractions: water soluble C (WSC) at 20 °C and hot water extractable C (HWEC) at 80 °C (Ghani et al, 2003). The fractions from Method 1 had the most distinct average 14C ages with O-min, FLF and IALF assessed as 206, 1965 and 6172 years before present (BP) respectively. The fractions from Method 2 fell into two age groups, < ~1000 years BP for s+c, rSOC and S+A and > 4000 years BP for DOC and POM. Both Method 3 fractions were dominated by modern C. The average 14C ages of FLF, IALF, DOC and POM were surprisingly higher than the mineral bound fractions, although they made up a relatively small

  20. Study on the interaction of the epilepsy drug, zonisamide with human serum albumin (HSA) by spectroscopic and molecular docking techniques

    NASA Astrophysics Data System (ADS)

    Shahabadi, Nahid; Khorshidi, Aref; Moghadam, Neda Hossinpour

    2013-10-01

    In the present investigation, an attempt has been made to study the interaction of zonisamide (ZNS) with the transport protein, human serum albumin (HSA) employing UV-Vis, fluorometric, circular dichroism (CD) and molecular docking techniques. The results indicated that binding of ZNS to HSA caused strong fluorescence quenching of HSA through static quenching mechanism, hydrogen bonds and van der Waals contacts are the major forces in the stability of protein ZNS complex and the process of the binding of ZNS with HSA was driven by enthalpy (ΔH = -193.442 kJ mol-1). The results of CD and UV-Vis spectroscopy showed that the binding of this drug to HSA induced conformational changes in HSA. Furthermore, the study of molecular docking also indicated that zonisamide could strongly bind to the site I (subdomain IIA) of HSA mainly by hydrophobic interaction and there were hydrogen bond interactions between this drug and HSA, also known as the warfarin binding site.

  1. X-ray spectroscopic technique for energetic electron transport studies in short-pulse laser/plasma interactions

    SciTech Connect

    Tutt, T.E.

    1994-12-01

    When a solid target is irradiated by a laser beam, the material is locally heated to a high temperature and a plasma forms. The interaction of the laser with plasma can produce energetic electrons. By observing the behavior of these {open_quotes}hot{close_quotes} electrons, we hope to obtain a better understanding of Laser/Plasma Interactions. In this work we employ a layered-fluorescer technique to study the transport, and therefore the energetics, of the electrons. The plasma forms on a thin foil of metallic Pd which is bonded to thin layer of metallic Sn. Electrons formed from the plasma penetrate first the Pd and then the Sn. In both layers the energetic electrons promote inner (K) shell ionization of the metallic atoms which leads to the emission of characteristic K{sub {alpha}} x-rays of the fluorescers. By recording the x-ray spectrum emitted by the two foils, we can estimate the energy-dependent range of the electrons and their numbers.

  2. RHIC SPIN FLIPPER

    SciTech Connect

    BAI,M.; ROSER, T.

    2007-06-25

    This paper proposes a new design of spin flipper for RHIC to obtain full spin flip with the spin tune staying at half integer. The traditional technique of using an rf dipole or solenoid as spin flipper to achieve full spin flip in the presence of full Siberian snake requires one to change the snake configuration to move the spin tune away from half integer. This is not practical for an operational high energy polarized proton collider like RHIC where beam lifetime is sensitive to small betatron tune change. The design of the new spin flipper as well as numerical simulations are presented.

  3. Studying Iron Mineralogy to Understand Redox Conditions in the Mesoproterozoic Belt Basin, USA Using Complementary Microscopic, Spectroscopic, and Magnetic Techniques

    NASA Astrophysics Data System (ADS)

    Slotznick, S. P.; Webb, S.; Kirschvink, J. L.; Fischer, W. W.

    2015-12-01

    Observations of iron chemistry and mineralogy over time provide a valuable tool for studying paleoenvironments, but questions still remain as to the redox character of Proterozoic basins after the rise of oxygen. To evaluate the mechanisms of iron mineralization in Proterozoic samples, we developed an approach that pairs the microscale textural techniques of light microscopy, magnetic scanning microscopy, and (synchrotron-based) microprobe x-ray spectroscopy with sensitive bulk rock magnetic experiments. Samples were collected from stratigraphic sections across the ~1.4 Ga lower Belt Group, Belt Supergroup, MT and ID, USA with a focus on excellently preserved sedimentary rocks, but also including those altered by a variety of diagenetic, metamorphic, and metasomatic events. Results show that even in the best-preserved parts of the Belt Basin, late diagenetic and/or metasomatic fluids affected (in some cases very mildly) the primary iron phases as evidenced by prevalent post-depositional alterations such as rare base metal sulfides. In more heavily altered rocks, the appearance of pyrrhotite and other minerals signaled transformations in iron mineralogy through metamorphism and metasomatism. Despite these secondary phases crystallizing in an open fluid-rich system, primary records of redox chemistry were preserved in the recrystallized early diagenetic framboidal pyrite and (sub)micron-sized detrital magnetite grains. Detrital magnetite is not the most abundant iron-bearing phase in any of the samples (typically <0.01 wt%), but is widely observed in both proximal and deeper basin facies, illustrating an important detrital flux of iron to the basin and a highly reactive iron source for early diagenetic pyrite. Based on our analyses, we interpret the shallow waters of the Belt Basin to be oxic with sulfidic pore fluids and deeper waters in parts of the basin as likely euxinic, consistent with the results of some bulk geochemical proxies. This redox reconstruction also

  4. Segmental extracellular and intracellular water distribution and muscle glycogen after 72-h carbohydrate loading using spectroscopic techniques.

    PubMed

    Shiose, Keisuke; Yamada, Yosuke; Motonaga, Keiko; Sagayama, Hiroyuki; Higaki, Yasuki; Tanaka, Hiroaki; Takahashi, Hideyuki

    2016-07-01

    Body water content increases during carbohydrate loading because 2.7-4-g water binds each 1 g of glycogen. Bioelectrical impedance spectroscopy (BIS) allows separate assessment of extracellular and intracellular water (ECW and ICW, respectively) in the whole body and each body segment. However, BIS has not been shown to detect changes in body water induced by carbohydrate loading. Here, we aimed to investigate whether BIS had sufficient sensitivity to detect changes in body water content and to determine segmental water distribution after carbohydrate loading. Eight subjects consumed a high-carbohydrate diet containing 12 g carbohydrates·kg body mass(-1)·day(-1) for 72 h after glycogen depletion cycling exercise. Changes in muscle glycogen concentration were measured by (13)C-magnetic resonance spectroscopy, and total body water (TBW) was measured by the deuterium dilution technique (TBWD2O). ICW and ECW in the whole body (wrist-to-ankle) and in each body segment (arm, trunk, and leg) were assessed by BIS. Muscle glycogen concentration [72.7 ± 10.0 (SD) to 169.4 ± 55.9 mmol/kg wet wt, P < 0.001] and TBWD2O (39.3 ± 3.2 to 40.2 ± 3.0 kg, P < 0.05) increased significantly 72 h after exercise compared with baseline, respectively. Whole-body BIS showed significant increases in ICW (P < 0.05), but not in ECW. Segmental BIS showed significant increases in ICW in the legs (P < 0.05), but not in the arms or trunk. Our results suggest that increase in body water after carbohydrate loading can be detected by BIS and is caused by segment-specific increases in ICW. PMID:27231310

  5. Use of spectroscopic and imaging techniques to evaluate pretreated sugarcane bagasse as a substrate for cellulase production under solid-state fermentation.

    PubMed

    Rodríguez-Zúñiga, Ursula Fabiola; Bertucci Neto, Victor; Couri, Sonia; Crestana, Silvio; Farinas, Cristiane Sanchez

    2014-03-01

    The enzymatic cocktail of cellulases is one of the most costly inputs affecting the economic viability of the biochemical route for biomass conversion into biofuels and other chemicals. Here, the influence of liquid hot water, dilute acid, alkali, and combined acid/alkali pretreatments on sugarcane bagasse (SCB) used for cellulase production was investigated by means of spectroscopic and imaging techniques. Chemical composition and structural characteristics, such as crystallinity (determined by X-ray diffraction), functional groups (Fourier transform infrared spectroscopy), and microstructure (scanning electron microscopy), were used to correlate SCB pretreatments with enzymatic biosynthesis by a strain of the filamentous fungus Aspergillus niger under solid-state fermentation. The combined acid/alkali pretreatment resulted in a SCB with higher cellulose content (86.7%). However, the high crystallinity (74%) of the resulting biomass was detrimental to microbial uptake and enzyme production. SCB pretreated with liquid hot water yielded the highest filter paper cellulase (FPase), carboxymethyl cellulase (CMCase), and xylanase activities (0.4, 14.9, and 26.1 U g(-1), respectively). The results showed that a suitable pretreatment for SCB to be used as a substrate for cellulase production should avoid severe conditions in order to preserve amorphous cellulose and to enhance the physical properties that assist microbial access. PMID:24363237

  6. Structure and spectroscopic analysis of the graphene monolayer film directly grown on the quartz substrate via the HF-CVD technique

    NASA Astrophysics Data System (ADS)

    Mahmoud, Waleed E.; Al-Hazmi, Farag S.; Al-Ghamdi, A. A.; Shokr, F. S.; Beall, Gary W.; Bronstein, Lyudmila M.

    2016-08-01

    Direct growth of a monolayer graphene film on a quartz substrate by a hot filament chemical vapor deposition technique is reported. The monolayer graphene film prepared was characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), selected area electron diffraction (SAED), and atomic force microscopy (AFM). The optical properties were studied by spectroscopic elliposmetry. The experimental data were fitted by the Forouhi-Bloomer model to estimate the extinction coefficient and the refractive index of the monolayer graphene film. The refractive index spectrum in the visible region was studied based on the harmonic oscillator model. The lattice dielectric constant, real and imaginary dielectric constants and the ratio of the charge carrier number to the effective mass were determined. The surface and volume energy loss parameters were also found and showed that the value of the surface energy loss is greater than the volume energy loss. The determination of these optical constants will open new avenue for novel applications of graphene films in the field of wave plates, light modulators, ultrahigh-frequency signal processing and LCDs.

  7. Studies on the interaction between promethazine and human serum albumin in the presence of flavonoids by spectroscopic and molecular modeling techniques.

    PubMed

    He, Ling-Ling; Wang, Zhi-Xin; Wang, Yong-Xia; Liu, Xian-Ping; Yang, Yan-Jie; Gao, Yan-Ping; Wang, Xin; Liu, Bin; Wang, Xin

    2016-09-01

    Fluorescence, absorption, time-correlated single photon counting (TCSPC), and circular dichroism (CD) spectroscopic techniques as well as molecular modeling methods were used to study the binding characterization of promethazine (PMT) to human serum albumin (HSA) and the influence of flavonoids, rutin and baicalin, on their affinity. The results indicated that the fluorescence quenching mechanism of HSA by PMT is a static quenching due to the formation of complex. The reaction was spontaneous and mainly mediated by hydrogen bonds and hydrophobic interactions. The binding distance between the tryptophan residue of HSA and PMT is less than 8nm, which indicated that the energy transfer from the tryptophan residue of HSA to PMT occurred. The binding site of PMT on HSA was located in sites I and the presence of PMT can cause the conformational changes of HSA. There was the competitive binding to HSA between PMT and flavonoids because of the overlap of binding sites in HSA. The flavonoids could decrease the association constant and increase the binding distance. In addition, their synergistic effect can further change the conformation of HSA. The decrease in the affinities of PMT binding to HSA in the presence of flavonoids may lead to the increase of free drug in blood, which would affect the transportation or disposition of drug and evoke an adverse or toxic effect. Hence, rationalising dosage and diet regimens should be taken into account in clinical application of PMT. PMID:27315330

  8. Spectroscopic Evidence for Strong Quantum Spin Fluctuations with Itinerant Character in YFe2Ge2

    SciTech Connect

    Sirica, N.; Bondino, F.; Nappini, S.; Piz, I.; Poudel, L.; Christianson, Andrew D.; Mandrus, D.; Singh, David J; Mannella, Norman

    2015-03-04

    We report x-ray absorption and photoemission spectroscopy of the electronic structure in the normal state of metallic YFe2Ge2. The data reveal evidence for large fluctuating spin moments on the Fe sites, as indicated by exchange multiplets appearing in the Fe 3s core-level photoemission spectra, even though the compound does not show magnetic order. The magnitude of the multiplet splitting is comparable to that observed in the normal state of the Fe-pnictide superconductors. This shows a connection between YFe2Ge2 and the Fe-based superconductors even though it contains neither pnictogens nor chalcogens. Finally, the implication is that the chemical range of compounds showing at least one of the characteristic magnetic signatures of the Fe-based superconductors is broader than previously thought.

  9. Orbital lesions: proton spectroscopic phase-dependent contrast MR imaging.

    PubMed

    Atlas, S W; Grossman, R I; Axel, L; Hackney, D B; Bilaniuk, L T; Goldberg, H I; Zimmerman, R A

    1987-08-01

    Thirteen orbital lesions in 12 patients were evaluated with both conventional spin-echo magnetic resonance (MR) imaging and phase-dependent proton spectroscopic imaging. This technique, which makes use of small differences in the resonant frequencies of water and fat protons, provides excellent high-resolution images with simultaneous chemical shift information. In this method, there is 180 degrees opposition of phase between fat protons and water protons at the time of the gradient echo, resulting in signal cancellation in voxels containing equal signals from fat and water. In this preliminary series, advantages of spectroscopic images in orbital lesions included better lesion delineation, with superior anatomic definition of orbital apex involvement; more specific characterization of high-intensity hemorrhage with a single pulse sequence; elimination of potential confusion from chemical shift misregistration artifact; further clarification of possible intravascular flow abnormalities; and improved apparent intralesional contrast. PMID:3602394

  10. Integrated approaches of x-ray absorption spectroscopic and electron microscopic techniques on zinc speciation and characterization in a final sewage sludge product.

    PubMed

    Kim, Bojeong; Levard, Clément; Murayama, Mitsuhiro; Brown, Gordon E; Hochella, Michael F

    2014-05-01

    Integration of complementary techniques can be powerful for the investigation of metal speciation and characterization in complex and heterogeneous environmental samples, such as sewage sludge products. In the present study, we combined analytical transmission electron microscopy (TEM)-based techniques with X-ray absorption spectroscopy (XAS) to identify and characterize nanocrystalline zinc sulfide (ZnS), considered to be the dominant Zn-containing phase in the final stage of sewage sludge material of a full-scale municipal wastewater treatment plant. We also developed sample preparation procedures to preserve the organic and sulfur-rich nature of sewage sludge matrices for microscopic and spectroscopic analyses. Analytical TEM results indicate individual ZnS nanocrystals to be in the size range of 2.5 to 7.5 nm in diameter, forming aggregates of a few hundred nanometers. Observed lattice spacings match sphalerite. The ratio of S to Zn for the ZnS nanocrystals is estimated to be 1.4, suggesting that S is present in excess. The XAS results on the Zn speciation in the bulk sludge material also support the TEM observation that approximately 80% of the total Zn has the local structure of a 3-nm ZnS nanoparticle reference material. Because sewage sludge is frequently used as a soil amendment on agricultural lands, future studies that investigate the oxidative dissolution rate of ZnS nanoparticles as a function of size and aggregation state and the change of Zn speciation during post sludge-processing and soil residency are warranted to help determine the bioavailability of sludge-born Zn in the soil environment. PMID:25602819

  11. J-Modulation in ID NMR 1H Spectrum of Taurine and Aspartate Using Spin-Echo Technique

    NASA Astrophysics Data System (ADS)

    Oturak, Halil; Sağlam, Adnan; Bahçeli, Semiha

    1999-05-01

    This study reports on a theoretical calculation of Hahn's spin-echo experiment in case of a model A2B2 spin system with a strongly coupling character and gives the experimental results of one-dimension 1H high-resolution NMR spectra of taurine and aspartate. The calculated amplitudes of the spin-echoes for two different proton groups of taurine are given. Using results of our calculations for taurine, the computer simulations of J-modulation are implemented. It is shown that the agreement be-tween the experimental and simulated spectra is good.

  12. Mass and Spin Measurement Techniques (for the Large Hadron Collider):. Lectures Given at TASI 2011, Boulder, Colorado

    NASA Astrophysics Data System (ADS)

    Lester, Christopher G.

    2013-12-01

    For TASI 2011, I was asked to give a series of lectures on "Mass and Spin Measurement Techniques" with relevance to the Large Hadron Collider. This document provides a written record of those lectures - or more precisely of what I said while giving the lectures - warts and all. It is provided as my contribution to the proceedings primarily for the benefit of those who heard the lectures first hand and may wish to refer back to them. What it is not is a scientific paper or a teaching resource. Though lecture slides may be prepared in advance, what is actually said in a lecture is usually extemporaneous, may be partial, can be influenced by audience reaction, and may not even make sense without a visual record of the concomitant gesticulations of the lecturer. More worryingly, some of the statements made may be down-right false, if the lecturer's tongue is in a twist. Accordingly, these proceedings are provided without warranty of any kind - not least in respect of accuracy or impartiality. The lectures were intended to engage the audience and get them thinking about a number of topics that they had not seen before. They were not expected to be the sort of sombre or well-balanced overview of the field that one might hope to achive in a review. These proceedings are provided to jog the memory of those who saw the lectures first hand, and for little other purpose. Footnotes, where they appear, indicate text/thoughts I have added during the editing process that were not voiced during the lectures themselves. Copies of the lecture slides are inserted at approximately the locations they would have become visible in the lectures.

  13. Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the -Ketoglutarate-Dependent Halogenase CyTc3 From Streptomyces

    SciTech Connect

    Fujimori, D.Galonic; Barr, E.W.; Matthews, M.L.; Koch, G.M.; Yonce, J.R.; Walsh, C.T.; Bollinger, J.M., Jr.; Krebs, C.; Riggs-Gelasco, P.J.

    2009-06-01

    The complex of the mononuclear non-heme halogenase CytC3 from Streptomyces, Fe(II), {alpha}-ketoglutarate, bromide, and the substrate l-2-aminobutyryl-S-CytC2 reacts with O{sub 2} to form a reaction intermediate. Variable-field, freeze-quench Moessbauer spectroscopy reveals this intermediate to be a mixture of two high-spin Fe(IV) complexes in an approximate 3.7/1 ratio. Freeze-quench Fe K-edge X-ray absorption spectroscopy provides further insight into the structure of this intermediate. A short 1.62-{angstrom} interaction between the Fe and one of its ligands is attributed to the Fe(IV)-oxo group, and a 2.43-{angstrom} interaction is assigned to the Fe-Br interaction. A significantly longer Fe-Br separation (2.53 {angstrom}) is observed in the reactant complex, consistent with lower valency of the Fe in the reactant complex. This intermediate is the first example for a Br-Fe(IV)-oxo complex in a protein and provides evidence for a unifying mechanism for Fe(II) and {alpha}-ketoglutarate-dependent dioxygenases and halogenases.

  14. Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the alpha-Ketoglutarate-Dependent Halogenase CytC3 from Streptomyces

    SciTech Connect

    Galonic Fujimori,D.; Barr, E.; Matthews, M.; Koch, G.; Yonce, J.; Walsh, C.; Bollinger, J.; Krebs, C.; Riggs-Gelasco, P.

    2007-01-01

    The complex of the mononuclear non-heme halogenase CytC3 from Streptomyces, Fe(II), {alpha}-ketoglutarate, bromide, and the substrate l-2-aminobutyryl-S-CytC2 reacts with O2 to form a reaction intermediate. Variable-field, freeze-quench Mossbauer spectroscopy reveals this intermediate to be a mixture of two high-spin Fe(IV) complexes in an approximate 3.7/1 ratio. Freeze-quench Fe K-edge X-ray absorption spectroscopy provides further insight into the structure of this intermediate. A short 1.62-Angstroms interaction between the Fe and one of its ligands is attributed to the Fe(IV)-oxo group, and a 2.43-Angstroms interaction is assigned to the Fe-Br interaction. A significantly longer Fe-Br separation (2.53 Angstroms) is observed in the reactant complex, consistent with lower valency of the Fe in the reactant complex. This intermediate is the first example for a Br-Fe(IV)-oxo complex in a protein and provides evidence for a unifying mechanism for Fe(II) and {alpha}-ketoglutarate-dependent dioxygenases and halogenases.

  15. The interaction of fructose-1,6-biphosphate aldolase with liposome membranes: a spin probe technique study.

    PubMed

    Komorowska, M; Langner, M; Gomułkiewicz, J

    1989-12-01

    Thermotropic properties of liposome membranes prepared of bulk bovine erythrocyte membrane lipids, native, or aldolase-modified, were investigated by the ESR method. Breaks were observed in the log 2T parallel vs 1/T plots for two spin labels: tempopalmitate and 5-doxyl-palmitate methyl ester. These phenomena have been interpreted as reflecting structural changes near the lipid bilayer polar heads region. Upon modification with aldolase, the temperature at which the breaks occurred was decreased for both spin probes. PMID:2558946

  16. Comparison of Y2O3:Bi3+ phosphor thin films fabricated by the spin coating and radio frequency magnetron techniques

    NASA Astrophysics Data System (ADS)

    Jafer, R. M.; Yousif, A.; Kumar, Vinod; Pathak, Trilok Kumar; Purohit, L. P.; Swart, H. C.; Coetsee, E.

    2016-09-01

    The reactive radio-frequency (RF) magnetron sputtering and spin coating fabrication techniques were used to fabricate Y2-xO3:Bix=0.5% phosphor thin films. The two techniques were analysed and compared as part of investigations being done on the application of down-conversion materials for a Si solar cell. The morphology, structural and optical properties of these thin films were investigated. The X-ray diffraction results of the thin films fabricated by both techniques showed cubic structures with different space groups. The optical properties showed different results because the Bi3+ ion is very sensitive towards its environment. The luminescence results for the thin film fabricated by the spin coating technique is very similar to the luminescence observed in the powder form. It showed three obvious emission bands in the blue and green regions centered at about 360, 410 and 495 nm. These emissions were related to the 3P1-1S0 transition of the Bi3+ ion situated in the two different sites of the Y2O3 matrix with I a-3(206) space group. Whereas the thin film fabricated by the radio frequency magnetron technique showed a broad single emission band in the blue region centered at about 416 nm. This was assigned to the 3P1-1S0 transition of the Bi3+ ion situated in one of the Y2O3 matrix's sites with a Fm-3 (225) space group. The spin coating fabrication technique is suggested to be the best technique to fabricate the Y2O3:Bi3+ phosphor thin films.

  17. High-resolution aluminum-27 solid-state magic-angle sample-spinning nuclear magnetic resonance spectroscopic study of AlCl sub 3 -tetrahydrofuran complexes

    SciTech Connect

    Han, Oc Hee; Oldfield, E. )

    1990-09-19

    The authors have obtained {sup 27}Al solid-state nuclear magnetic resonance (NMR) spectra of several AlCl{sub 3}-THF complexes, using magic-angle sample-spinning (MASS) NMR at high field. The authors results suggest that the isotropic chemical shifts ({delta}{sub i}) occur in relatively well defined regions for 4-, 5-, and 6-coordinate species (AlCl{sub 4}{sup {minus}}, {approximately} 103 ppm; AlCl{sub 3}{center dot}THF, {approximately} 99 ppm; trans-AlCl{sub 3}{center dot}2THF, {approximately} 60 ppM; trans-(AlCl{sub 2}(THF){sub 4}){sup +}, {approximately} 14 ppM), as found previously with aluminum oxo compounds. They also find that theoretically calculated average nuclear quadrupole coupling constants (e{sup 2}qQ/h) (trans-(AlCl{sub 2}(THF){sub 4}){sup +}, {approximately} 6.3 MHz; trans-AlCl{sub 3}{center dot}2THF, {approximately} 4.6 MHz; AlCl{sub 3}{center dot}THF, {approximately} 3.0 MHz; AlCl{sub 4}{sup {minus}}, 0 MHz) are in good accord with experimentally determined nuclear quadrupole coupling constants, determined from computer simulations of the MASS NMR spectra (trans-(AlCl{sub 2}(THF){sub 4}){sup +}, 6.4 MHz; trans-AlCl{sub 3}{center dot}2THF, 4.9 MHz; AlCl{sub 3}{center dot}THF, 4.7 MHz; AlCl{sub 4}{sup {minus}}, 0.3 MHz). Both {sup 27}Al {delta}{sub i} and e{sup 2}qQ/h determinations appear to be useful as probes of structure in these systems, and thus offer a facile means of monitoring various solid-state reactions. 14 refs., 3 figs., 3 tabs.

  18. High-Spin Cobalt Hydrides for Catalysis

    SciTech Connect

    Holland, Patrick L.

    2013-08-29

    Organometallic chemists have traditionally used catalysts with strong-field ligands that give low-spin complexes. However, complexes with a weak ligand field have weaker bonds and lower barriers to geometric changes, suggesting that they may lead to more rapid catalytic reactions. Developing our understanding of high-spin complexes requires the use of a broader range of spectroscopic techniques, but has the promise of changing the mechanism and/or selectivity of known catalytic reactions. These changes may enable the more efficient utilization of chemical resources. A special advantage of cobalt and iron catalysts is that the metals are more abundant and cheaper than those currently used for major industrial processes that convert unsaturated organic molecules and biofeedstocks into useful chemicals. This project specifically evaluated the potential of high-spin cobalt complexes for small-molecule reactions for bond rearrangement and cleavage reactions relevant to hydrocarbon transformations. We have learned that many of these reactions proceed through crossing to different spin states: for example, high-spin complexes can flip one electron spin to access a lower-energy reaction pathway for beta-hydride elimination. This reaction enables new, selective olefin isomerization catalysis. The high-spin cobalt complexes also cleave the C-O bond of CO2 and the C-F bonds of fluoroarenes. In each case, the detailed mechanism of the reaction has been determined. Importantly, we have discovered that the cobalt catalysts described here give distinctive selectivities that are better than known catalysts. These selectivities come from a synergy between supporting ligand design and electronic control of the spin-state crossing in the reactions.

  19. Spectroscopic ellipsometry of Zn(1-x)Cu(x)O thin films based on a modified sol-gel dip-coating technique.

    PubMed

    Al-Khanbashi, Hibah A; Shirbeeny, W; Al-Ghamdi, A A; Bronstein, Lyudmila M; Mahmoud, Waleed E

    2014-01-24

    Nanocrystalline Zn(1-x)Cu(x)O thin films (x=0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by sol-gel dip-coating technique on a quartz substrate. These films were annealed at 350°C for 2 h. The X-ray diffraction showed a hexagonal crystal structure with high intensity peak for the (002) reflection plane indicating preferential growth along the c-axis of the crystal lattice. The peak position related to the (002) peak was shifted as a result of the copper ion incorporation, confirming the interstitial substitution of the zinc ions by the copper ions. This interstitial substitution leads to a decrease of an average crystallite size and lattice constants and an increase of the micro-strain up to 2 at.% of the copper amount. The surface morphology was explored by scanning electron microscopy which confirmed the homogenous distribution of nanoparticles in the deposited films along the quartz substrates. The energy dispersion X-ray spectroscopy revealed absence of impurities in the as-deposited films. The high resolution electron microscopy and selected area electron diffraction depicted that the films have polycrystalline nature. The film thickness and optical constants of the Zn(1-x)Cu(x)O thin films were estimated by fitting the spectroscopic ellipsometric data (ψ and Δ) using three different models. The refractive index was fitted using harmonic oscillator model from which the oscillator and the dispersive energies were found. The dielectric constant, dielectric loss, energy loss functions were also determined. PMID:24157332

  20. (1)H NMR spectroscopic elucidation in solution of the kinetics and thermodynamics of spin crossover for an exceptionally robust Fe(2+) complex.

    PubMed

    Petzold, Holm; Djomgoue, Paul; Hörner, Gerald; Speck, J Matthäus; Rüffer, Tobias; Schaarschmidt, Dieter

    2016-09-21

    A series of Fe(2+) spin crossover (SCO) complexes [Fe(5/6)](2+) employing hexadentate ligands (5/6) with cis/trans-1,2-diamino cyclohexanes (4) as central building blocks were synthesised. The ligands were obtained by reductive amination of 4 with 2,2'-bipyridyl-6-carbaldehyde or 1,10-phenanthroline-2-carbaldehyde 3. The chelating effect and the rigid structure of the ligands 5/6 lead to exceptionally robust Fe(2+) and Zn(2+) complexes conserving their structure even in coordinating solvents like dmso at high temperatures. Their solution behavior was investigated using variable temperature (VT) (1)H NMR spectroscopy and VT Vis spectroscopy. SCO behavior was found for all Fe(2+) complexes in this series centred around and far above room temperature. For the first time we have demonstrated that the thermodynamics as well as kinetics for SCO can be deduced by using VT (1)H NMR spectroscopy. An alternative scheme using a linear correction term C(1) to model chemical shifts for Fe(2+) SCO complexes is presented. The rate constant for the SCO of [Fe(rac-trans-5)](2+) obtained by VT (1)H NMR was validated by Laser Flash Photolysis (LFP), with excellent agreement (1/(kHL + kLH) = 33.7/35.8 ns for NMR/LFP). The solvent dependence of the transition temperature T1/2 and the solvatochromism of complex [Fe(rac-trans-5)](2+) were ascribed to hydrogen bond formation of the secondary amine to the solvent. Enantiomerically pure complexes can be prepared starting with R,R- or S,S-1,2-diaminocyclohexane (R,R-trans-4 or S,S-trans-4). The high robustness of the complexes reduces a possible ligand scrambling and allows preparation of quasiracemic crystals of [Zn(R,R-5)][Fe(S,S-5)](ClO4)4·(CH3CN) composed of a 1 : 1 mixture of the Zn and Fe complexes with inverse chirality. PMID:27506162

  1. Spectroscopic Evidence for Covalent Binding of Sulfadiazine to Natural Soils via 1,4-nucleophilic addition (Michael Type Addition) studied by Spin Labeling ESR

    NASA Astrophysics Data System (ADS)

    Aleksandrova, Olga

    2015-04-01

    Among different classes of veterinary pharmaceuticals, Sulfadiazine (SDZ) is widely used in animal husbandry. Its residues were detected in different environmental compartments. However, soil is a hot spot for SDZ as it receives a large portion of excreted compounds through the application of manure during soil fertilization. Ample studies on the fate of SDZ in soils showed that a large portion forms nonextractable residues (NER) along with transformation products and a low mineralization (Mueller et al., 2013). A common observation was an initially fast formation of NER up to 10% of the applied amount promptly after the application of SDZ to soil, and this portion increased up to 50% within a few days (Mueller et al., 2013; Nowak et al., 2011). A common finding for SDZ, as for other sulfonamides, was biphasic kinetics of the formation of NER, which was attributed to the occurrence of two reaction processes: a rapid, often reversible process and a slower, irreversible process (Weber et al., 1996). A single-phase reaction process was also established under anaerobic treatment (Gulkowska et al., 2014). A major focus of this work is to elucidate a reaction mechanism of covalent binding of SDZ to soil that is currently required to estimate a risk of NER formed by SDZ in soils for human health. Taking into account a key role of the amine functional groups of SDZ on its reactivity in soil, nitroxide radicals with the sewed aromatic or aliphatic amines labeled soil samples and then, were investigated by means of ESR spectroscopy. 2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-yloxy and 4-amino-2,2,6,6-Tetramethylpiperidin-1-oxyl modeled decomposition products of SDZ with the aromatic and aliphatic amines, respectively. The application of the defined combination of both spin labels (SL) to different soils well simulated a change of a paramagnetic signal of soil organic radicals interacted with SDZ. After their application to soil, SL were found in soil sites characterized

  2. Spectroscopic Evidence for Covalent Binding of Sulfadiazine to Natural Soils via 1,4-nucleophilic addition (Michael Type Addition) studied by Spin Labeling ESR

    NASA Astrophysics Data System (ADS)

    Aleksandrova, Olga

    2015-04-01

    Among different classes of veterinary pharmaceuticals, Sulfadiazine (SDZ) is widely used in animal husbandry. Its residues were detected in different environmental compartments. However, soil is a hot spot for SDZ as it receives a large portion of excreted compounds through the application of manure during soil fertilization. Ample studies on the fate of SDZ in soils showed that a large portion forms nonextractable residues (NER) along with transformation products and a low mineralization (Mueller et al., 2013). A common observation was an initially fast formation of NER up to 10% of the applied amount promptly after the application of SDZ to soil, and this portion increased up to 50% within a few days (Mueller et al., 2013; Nowak et al., 2011). A common finding for SDZ, as for other sulfonamides, was biphasic kinetics of the formation of NER, which was attributed to the occurrence of two reaction processes: a rapid, often reversible process and a slower, irreversible process (Weber et al., 1996). A single-phase reaction process was also established under anaerobic treatment (Gulkowska et al., 2014). A major focus of this work is to elucidate a reaction mechanism of covalent binding of SDZ to soil that is currently required to estimate a risk of NER formed by SDZ in soils for human health. Taking into account a key role of the amine functional groups of SDZ on its reactivity in soil, nitroxide radicals with the sewed aromatic or aliphatic amines labeled soil samples and then, were investigated by means of ESR spectroscopy. 2,5,5-Trimethyl-2-(3-aminophenyl)pyrrolidin-1-yloxy and 4-amino-2,2,6,6-Tetramethylpiperidin-1-oxyl modeled decomposition products of SDZ with the aromatic and aliphatic amines, respectively. The application of the defined combination of both spin labels (SL) to different soils well simulated a change of a paramagnetic signal of soil organic radicals interacted with SDZ. After their application to soil, SL were found in soil sites characterized

  3. Magic Angle Spinning NMR Spectroscopy: A Versatile Technique for Structural and Dynamic Analysis of Solid-Phase Systems

    PubMed Central

    Polenova, Tatyana; Gupta, Rupal; Goldbourt, Amir

    2016-01-01

    Magic Angle Spinning (MAS) NMR spectroscopy is a powerful method for analysis of a broad range of systems, including inorganic materials, pharmaceuticals, and biomacromolecules. The recent developments in MAS NMR instrumentation and methodologies opened new vistas to atomic-level characterization of a plethora of chemical environments previously inaccessible to analysis, with unprecedented sensitivity and resolution. PMID:25794311

  4. An in-line micro-pyrolysis system to remove contaminating organic species for precise and accurate water isotope analysis by spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Panetta, R. J.; Hsiao, G.

    2011-12-01

    Trace levels of organic contaminants such as short alcohols and terpenoids have been shown to cause spectral interference in water isotope analysis by spectroscopic techniques. The result is degraded precision and accuracy in both δD and δ18O for samples such as beverages, plant extracts or slightly contaminated waters. An initial approach offered by manufacturers is post-processing software that analyzes spectral features to identify and flag contaminated samples. However, it is impossible for this software to accurately reconstruct the water isotope signature, thus it is primarily a metric for data quality. Here, we describe a novel in-line pyrolysis system (Micro-Pyrolysis Technology, MPT) placed just prior to the inlet of a cavity ring-down spectroscopy (CRDS) analyzer that effectively removes interfering organic molecules without altering the isotope values of the water. Following injection of the water sample, N2 carrier gas passes the sample through a micro-pyrolysis tube heated with multiple high temperature elements in an oxygen-free environment. The temperature is maintained above the thermal decomposition threshold of most organic compounds (≤ 900 oC), but well below that of water (~2000 oC). The main products of the pyrolysis reaction are non-interfering species such as elemental carbon and H2 gas. To test the efficacy and applicability of the system, waters of known isotopic composition were spiked with varying amounts of common interfering alcohols (methanol, ethanol, propanol, hexanol, trans-2-hexenol, cis-3-hexanol up to 5 % v/v) and common soluble plant terpenoids (carveol, linalool, geraniol, prenol). Spiked samples with no treatment to remove the organics show strong interfering absorption peaks that adversely affect the δD and δ18O values. However, with the MPT in place, all interfering absorption peaks are removed and the water absorption spectrum is fully restored. As a consequence, the δD and δ18O values also return to their original

  5. Oxygen vacancies induced Spin polarized current in Co-doped ZnO by Andreev reflection technique

    NASA Astrophysics Data System (ADS)

    Yang, Kung-Shang; Chou, Hsiung; Chan, Wen Ling; Chen, Bo-Yu; Shang-Fan Lee Collaboration

    Dilute magnetic semiconductor (DMO) is a semiconducting system with spin-polarized carriers and magnetic properties. However, since most studies had been focused on existence of FM, the proportion of spin-polarized current (SPC) in DMO is far from being determined. We used Point-contact Andreev reflection measurements on various Zn0.95Co0.05O thin films, with controlled oxygen vacancies by sputtering in various H2 partial pressure with Ar atmosphere. We found that conductance versus voltage (G-V) spectra suppresses as oxygen vacancy concentration increases. It indicates oxygen vacancies play significant role in inducing the SPC. To understand the origin of spin polarized current at the interface of the superconducting tip/CZO system, we use modified Blonder-Tinkham-Klapwijk (MBTK) model in ballistic and diffusive regime to interpret GV curve. The extracted SPC value were up to 70% in ballistic regime and 65% in diffusive regime. The results suggest tiny routes have been formed by oxygen vacancies which are extended throughout the whole films. This result confirmed that MBTK model in ballistic regime is more suitable for our GV spectra and this explains the observation of such a high SPC Institute of Physics, Academia Sinica Taiwan.

  6. Vessel-selective, non-contrast enhanced, time-resolved MR angiography with vessel-selective arterial spin labeling technique (CINEMA-SELECT) in intracranial arteries.

    PubMed

    Nakamura, Masanobu; Yoneyama, Masami; Tabuchi, Takashi; Takemura, Atsushi; Obara, Makoto; Tatsuno, Satoshi; Sawano, Seishi

    2013-07-01

    We demonstrate the feasibility of the vessel-selective, non-contrast, time-resolved magnetic resonance angiography (MRA) technique, "contrast inherent inflow enhanced multi-phase angiography combining vessel-selective arterial spin labeling technique (CINEMA-SELECT)". This sequence consists of two major techniques: pulsed star labeling of arterial regions (PULSAR) and Look-Locker sampling. We hypothesize that this technique allows selective labeling of single intracranial arteries, consisting of high-resolution four-dimensional data with a wide coverage of the brain. In this study, a new vessel-selective, time-resolved angiographic technique is demonstrated that can produce individual angiograms non-invasively by labeling the principal arterial vessels proximal to the circle of Willis. Clear vessel delineation is achieved, and the separation of the three vessels is evident in healthy volunteers. This technique could play an important role in the assessment of the structure and hemodynamics of intracranial arteries without the use of contrast agents. PMID:23475783

  7. The porous nature of ZnO thin films deposited by sol-gel Spin-Coating technique

    NASA Astrophysics Data System (ADS)

    Karyaoui, M.; Ben Jaballah, A.; Mechiak, R.; Chtourou, R.

    2012-02-01

    Zinc oxide (ZnO) thin films were deposited on silicon and quartz substrates, by sol-gel method, using zinc acetate dehydrate [Zn(CH3COO)2.2H2O] dissolved in isopropanol and glycerol. The structural, morphologic and optical properties of ZnO thin films subsequently annealed at 700°C in air for 30 min have leads to a porous nature of these films. To calculate, the refraction index and the extinction coefficient values, Cauchy formalism is used to evaluate the Spectroscopic Ellipsometry results. Two distinct configurations were proposed for each sample: in the first, the film is considered as mixture of randomly distributed voids and ZnO crystallites while in the second, the effect of porosity gradient is highlighted. This optical analysis gives a better agreement between experiment and theory for a wide range of wavelengths regarding the second configuration.

  8. Kinetic effects on double hysteresis in spin crossover molecular magnets analyzed with first order reversal curve diagram technique

    SciTech Connect

    Stan, Raluca-Maria; Gaina, Roxana; Enachescu, Cristian E-mail: radu.tanasa@uaic.ro; Stancu, Alexandru; Tanasa, Radu E-mail: radu.tanasa@uaic.ro; Bronisz, Robert

    2015-05-07

    In this paper, we analyze two types of hysteresis in spin crossover molecular magnets compounds in the framework of the First Order Reversal Curve (FORC) method. The switching between the two stable states in these compounds is accompanied by hysteresis phenomena if the intermolecular interactions are higher than a threshold. We have measured the static thermal hysteresis (TH) and the kinetic light induced thermal hysteresis (LITH) major loops and FORCs for the polycrystalline Fe(II) spin crossover compound [Fe{sub 1−x}Zn{sub x}(bbtr){sub 3}](ClO{sub 4}){sub 2} (bbtr = 1,4-di(1,2,3-triazol-1-yl)butane), either in a pure state (x = 0) or doped with Zn ions (x = 0.33) considering different sweeping rates. Here, we use this method not only to infer the domains distribution but also to disentangle between kinetic and static components of the LITH and to estimate the changes in the intermolecular interactions introduced by dopants. We also determined the qualitative relationship between FORC distributions measured for TH and LITH.

  9. Spectroscopically Unlocking Exoplanet Characteristics

    NASA Astrophysics Data System (ADS)

    Lewis, Nikole

    2016-05-01

    Spectroscopy plays a critical role in a number of areas of exoplanet research. The first exoplanets were detected by precisely measuring Doppler shifts in high resolution (R ~ 100,000) stellar spectra, a technique that has become known as the Radial Velocity (RV) method. The RV method provides critical constraints on exoplanet masses, but is currently limited to some degree by robust line shape predictions. Beyond the RV method, spectroscopy plays a critical role in the characterization of exoplanets beyond their mass and radius. The Hubble Space Telescope has spectroscopically observed the atmospheres of exoplanets that transit their host stars as seen from Earth giving us key insights into atmospheric abundances of key atomic and molecular species as well as cloud optical properties. Similar spectroscopic characterization of exoplanet atmospheres will be carried out at higher resolution (R ~ 100-3000) and with broader wavelength coverage with the James Webb Space Telescope. Future missions such as WFIRST that seek to the pave the way toward the detection and characterization of potentially habitable planets will have the capability of directly measuring the spectra of exoplanet atmospheres and potentially surfaces. Our ability to plan for and interpret spectra from exoplanets relies heavily on the fidelity of the spectroscopic databases available and would greatly benefit from further laboratory and theoretical work aimed at optical properties of atomic, molecular, and cloud/haze species in the pressure and temperature regimes relevant to exoplanet atmospheres.

  10. Spin Transport in Silicon

    NASA Astrophysics Data System (ADS)

    Appelbaum, Ian

    2008-03-01

    Silicon has been broadly viewed as the ideal material for spintronics due to its low atomic weight, lattice inversion symmetry, and near lack of nuclear spin, resulting in exceptionally long spin lifetime. Despite this appeal, however, the experimental difficulties of achieving coherent spin transport in silicon were overcome for the first time only recently, by using unique spin-polarized hot-electron injection and detection techniques. [1] Our subsequent observations of very long spin lifetimes and transit lengths [2] have impact on prospects for Silicon spintronics as the basis for a new paradigm of information processing. [1] Ian Appelbaum, Biqin Huang, and Douwe J. Monsma, ``Electronic measurement and control of spin transport in silicon,'' Nature 447, 295 (2007). [2] Biqin Huang, Douwe J. Monsma, and Ian Appelbaum, ``Coherent spin transport through a 350-micron-thick silicon wafer,'' Phys. Rev. Lett. 99, 177209 (2007).