WorldWideScience

Sample records for narrow line paramagnetic

  1. QSOs with narrow emission lines

    Baldwin, J.A.; Mcmahon, R.; Hazard, C.; Williams, R.E.

    1988-01-01

    Observations of two new high-redshift, narrow-lined QSOs (NLQSOs) are presented and discussed together with observations of similar objects reported in the literature. Gravitational lensing is ruled out as a possible means of amplifying the luminosity for one of these objects. It is found that the NLQSOs have broad bases on their emission lines as well as the prominent narrow cores which define this class. Thus, these are not pole-on QSOs. The FWHM of the emission lines fits onto the smoothly falling tail of the lower end of the line-width distribution for complete QSO samples. The equivalent widths of the combined broad and narrow components of the lines are normal for QSOs of the luminosity range under study. However, the NLQSOs do show ionization differences from broader-lined QSOs; most significant, the semiforbidden C III/C IV intensity ratio is unusually low. The N/C abundance ratio in these objects is found to be normal; the Al/C abundance ratio may be quite high. 38 references

  2. Properties of Narrow line Seyfert 1 galaxies

    Rakshit, Suvendu; Stalin, Chelliah Subramonian; Chand, Hum; Zhang, Xue-Guang

    2018-04-01

    Narrow line Seyfert 1 (NLSy1) galaxies constitute a class of active galactic nuclei characterized by the full width at half maximum (FWHM) of the Hα broad emission line 10 pixel-1. A strong correlation between the Hα and Hα emission lines is found both in the FWHM and flux. The nuclear continuum luminosity is found to be strongly correlated with the luminosity of Hα, Hα and [O III] emission lines. The black hole mass in NLSy1 galaxies is lower compared to their broad line counterparts. Compared to BLSy1 galaxies, NLSy1 galaxies have a stronger FeII emission and a higher Eddington ratio that place them in the extreme upper right corner of the R4570 - λEdd diagram. The distribution of the radio-loudness parameter (R) in NLSy1 galaxies drops rapidly at R>10 compared to the BLSy1 galaxies that have powerful radio jets. The soft X-ray photon index in NLSy1 galaxies is on average higher (2.9 ± 0.9) than BLSy1 galaxies (2.4 ± 0.8). It is anti-correlated with the Hα width but correlated with the FeII strength. NLSy1 galaxies on average have a lower amplitude of optical variability compared to their broad lines counterparts. These results suggest Eddington ratio as the main parameter that drives optical variability in these sources.

  3. Formation of extremely narrow metallic lines

    Harris, E.P.; Keyes, R.W.

    1979-01-01

    A method for forming metal lines, particularly lines which are superconductive, involves delineating a pattern on a thin metal film on a substrate by masking techniques, ion implanting the metal film to a desired depth, removing the mask and etching away the unimplanted portion of the metal film to leave the line whose width is equal to the implanted depth. (U.K.)

  4. Investigating the Temperature Problem in Narrow Line Emitting AGN

    Jenkins, Sam; Richardson, Chris T.

    2018-06-01

    Our research investigates the physical conditions in gas clouds around the narrow line region of AGN. Specifically, we explore the necessary conditions for anomalously high electron temperatures, Te, in those clouds. Our 321 galaxy data set was acquired from SDSS DR14 after requiring S/N > 5.0 in [OIII] 4363 and S/N > 3.0 in all BPT diagram emission lines, to ensure both accurate Te and galaxy classification, with 0.04 study the effects these conditions have on gas cloud Te.

  5. Narrow Quasar Absorption Lines and the History of the Universe

    Liebscher, Dierck-Ekkehard

    In order to get an estimation of the parameters of the cosmological model the statistics of narrow absorption lines in quasar spectra is evaluated. To this end a phenomenological model of the evolution of the corresponding absorbers in density, size, number and dimension is presented and compared with the observed evolution in the spectral density of the lines and their column density seen in the equivalent width. In spite of the wide range of possible models, the Einstein-deSitter model is shown to be unlikely because of the implied fast evolution in mass.

  6. Extended Narrow-Line Region in Seyfert Galaxies

    Enrico Congiu

    2017-10-01

    Full Text Available We present our recent results about the extended narrow-line region (ENLR of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212 obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1 galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a the contribution of shocks in ionizing the high velocity gas, (b the complex kinematics showed by the profile of the emission lines, (c the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  7. Extended Narrow-Line Region in Seyfert Galaxies

    Congiu, Enrico [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Contini, Marcella [School of Physics and Astronomy, Tel Aviv University, Tel Aviv (Israel); Ciroi, Stefano; Cracco, Valentina [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Di Mille, Francesco [Las Campanas Observatory, La Serena (Chile); Berton, Marco [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy); Astronomical Observatory of Brera, National Institute for Astrophysics, Milan (Italy); Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero, E-mail: enrico.congiu@phd.unipd.it [Dipartimento di Fisica e Astronomia “G. Galilei”, Università di Padova, Padova (Italy)

    2017-10-24

    We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  8. Extended Narrow-Line Region in Seyfert Galaxies

    Congiu, Enrico; Contini, Marcella; Ciroi, Stefano; Cracco, Valentina; Di Mille, Francesco; Berton, Marco; Frezzato, Michele; La Mura, Giovanni; Rafanelli, Piero

    2017-01-01

    We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modeling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as (a) the contribution of shocks in ionizing the high velocity gas, (b) the complex kinematics showed by the profile of the emission lines, (c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.

  9. Are Narrow Line Seyfert 1 Galaxies Viewed Pole-on?

    2011-04-01

    0.2’’ respectively. Figure 1 displays the position of each slit over a Barbosa et al. (2009) GMOS IFU image of the [S III] flux (which originates...C. Winge, H. Schmitt: Gemini/ GMOS IFU gas velocity ’tomography’ of the narrow line region of nearby active galaxies, MNRAS, 396 (2009) 2. [2] D...1995) 81. 4 P o S ( N L S 1 ) 0 5 0 Are NLS1s Pole-on? Travis C. Fischer 5 Figure 1: NGC 4051 GMOS IFU image showing integrated [SIII] flux

  10. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Rakshit, Suvendu; Stalin, C. S.

    2017-06-01

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z anti-correlated with Fe II strength but correlated with the width of the Hβ line. The well-known anti-correlation of variability-luminosity and the variability-Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  11. Occurrence and Global Properties of Narrow CIV lambda 1549 Absorption Lines in Moderate-Redshift Quasars

    Vestergaard, Marianne

    2003-01-01

    A statistical study is presented of (a) the frequency of narrow CIV lambda 1549 absorption lines in 1.5 ~50%) of narrow CIV absorbers is detected for the radio-quiet and radio-loud quasars, and a constant ~25% of all the quasars, irrespective of radio type display associated CIV absorbers stronger...

  12. Optocoupled line receiver input discriminates against narrow noise pulses

    Napier, T M

    1977-01-01

    Describes a simple optocoupled interface which connects a data line to the receiving end of a data link that features pulse length discrimination to enhance noise pulse rejection. A rugged red LED, D /sub 1/, can bypass any reasonable fault currents to protect the relatively fragile optocoupler input diode. (0 refs).

  13. Narrow-line laser cooling by adiabatic transfer

    Norcia, Matthew A.; Cline, Julia R. K.; Bartolotta, John P.; Holland, Murray J.; Thompson, James K.

    2018-02-01

    We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.

  14. Narrow absorption lines complex I: one form of broad absorption line

    Lu, Wei-Jian; Lin, Ying-Ru

    2018-03-01

    We discover that some of the broad absorption lines (BALs) are actually a complex of narrow absorption lines (NALs). As a pilot study of this type of BAL, we show this discovery through a typical example in this paper. Utilizing the two-epoch observations of J002710.06-094435.3 (hereafter J0027-0944) from the Sloan Digital Sky Survey (SDSS), we find that each of the C IV and Si IV BAL troughs contains at least four NAL doublets. By resolving the Si IV BAL into multiple NALs, we present the following main results and conclusions. First, all these NALs show coordinated variations between the two-epoch SDSS observations, suggesting that they all originate in the quasar outflow, and that their variations are due to global changes in the ionization condition of the absorbing gas. Secondly, a BAL consisting of a number of NAL components indicates that this type of BAL is basically the same as the intrinsic NAL, which tends to support the inclination model rather than the evolution model. Thirdly, although both the C IV and Si IV BALs originate from the same clumpy substructures of the outflow, they show different profile shapes: multiple absorption troughs for the Si IV BAL in a wider velocity range, while P-Cygni for the C IV BAL in a narrower velocity range. This can be interpreted by the substantial differences in fine structure and oscillator strength between the Si IVλλ1393, 1402 and C IVλλ1548, 1551 doublets. Based on the above conclusions, we consider that the decomposition of a BAL into NALs can serve as a way to resolve the clumpy structure for outflows, and it can be used to learn more about characteristics of the clumpy structure and to test the outflow model, when utilizing high-resolution spectra and photoionization model.

  15. Optical Variability of Narrow-line and Broad-line Seyfert 1 Galaxies

    Rakshit, Suvendu; Stalin, C. S., E-mail: suvenduat@gmail.com [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India)

    2017-06-20

    We studied the optical variability (OV) of a large sample of narrow-line Seyfert 1 (NLSy1) and broad-line Seyfert 1 (BLSy1) galaxies with z < 0.8 to investigate any differences in their OV properties. Using archival optical V -band light curves from the Catalina Real Time Transient Survey that span 5–9 years and modeling them using damped random walk, we estimated the amplitude of variability. We found that NLSy1 galaxies as a class show lower amplitude of variability than their broad-line counterparts. In the sample of both NLSy1 and BLSy1 galaxies, radio-loud sources are found to have higher variability amplitude than radio-quiet sources. Considering only sources that are detected in the X-ray band, NLSy1 galaxies are less optically variable than BLSy1 galaxies. The amplitude of variability in the sample of both NLSy1 and BLSy1 galaxies is found to be anti-correlated with Fe ii strength but correlated with the width of the H β line. The well-known anti-correlation of variability–luminosity and the variability–Eddington ratio is present in our data. Among the radio-loud sample, variability amplitude is found to be correlated with radio-loudness and radio-power, suggesting that jets also play an important role in the OV in radio-loud objects, in addition to the Eddington ratio, which is the main driving factor of OV in radio-quiet sources.

  16. Laser-induced fluorescence line narrowing in atomic vapors

    Meier, T.; Schuessler, H.A.

    1983-01-01

    The use of highly monochromatic light allows the selective excitation of atoms in vapors if excitation and detection of the fluorescence is carried out collinearly. The atoms capable of absorbing light then form an atomic beam of well defined velocity along the direction of the laser beam, but no velocity selection occurs perpendicular to it. The potential of the technique for Doppler-free atomic spectroscopy and for the study of excited atom collisions is demonstrated using the Na D 1 line as an example

  17. A study of the structure and kinematics of the narrow-line region in Seyfert galaxies

    Veilleux, S.

    1989-01-01

    The results of a high resolution study of the narrow emission line profiles of 16 Seyfert galaxies are presented. It is shown that the line profile parameters published in earlier low resolution studies are sometimes strongly influenced by resolution effects. In spite of these important systematic errors, many of the results derived from low resolution data are confirmed in the high resolution data. The narrow line profiles of Seyfert galaxies have a stronger base relative to core than a Gaussian. Most of the emission lines present a blueward asymmetry in the lower portion of their profile. In some galaxies, the line widths and/or line asymmetries are correlated with the ionization potential and/or critical density of the lines. There is a weak correlation between the line asymmetry and the dust content of the narrow line region (NLR). The large scatter in this relation, the absence of a similar correlation in Seyfert 1 to 1.5 galaxies, and the presence of a blue asymmetry in galaxies with dustfree line-emitting regions suggest that dust obscuration is not the only mechanism responsible for the line asymmetry in active galaxies. An optically-thick disk close to the nucleus is proposed as the other source of line asymmetry. An important result is that the host galaxy is probably playing a role in the kinematics of some of the gas in the NLR. A multicomponent model of the NLR is proposed to explain these results

  18. Reddening and He i{sup ∗} λ 10830 Absorption Lines in Three Narrow-line Seyfert 1 Galaxies

    Zhang, Shaohua; Zhou, Hongyan; Shi, Xiheng; Pan, Xiang; Ji, Tuo; Jiang, Peng; Wang, Shufen [Polar Research Institute of China, 451 Jinqiao Road, Shanghai, 200136 (China); Liu, Wenjuan [Key Laboratory for the Structure and Evolution of Celestial Objects, Yunnan Observatories, Chinese Academy of Sciences, Kunming, Yunnan 650011 (China); Jiang, Ning, E-mail: zhangshaohua@pric.org.cn, E-mail: zhouhongyan@pric.org.cn [Key Laboratory for Researches in Galaxies and Cosmology, Department of Astronomy, University of Sciences and Technology of China, Chinese Academy of Sciences, Hefei, Anhui, 230026 (China)

    2017-08-20

    We report the detection of heavy reddening and the He i* λ 10830 absorption lines at the active galactic nucleus (AGN) redshift in three narrow-line Seyfert 1 galaxies: SDSS J091848.61+211717.0, SDSS J111354.66+124439.0, and SDSS J122749.13+321458.9. They exhibit very red optical to near-infrared colors, narrow Balmer/Paschen broad emission lines and He i* λ 10830 absorption lines. The ultraviolet-optical-infrared nucleus continua are reddened by the SMC extinction law of E ( B − V ) ∼ 0.74, 1.17, and 1.24 mag for three objects, which are highly consistent with the values obtained from the broad-line Balmer decrements, but larger than those of narrow emission lines. The reddening analysis suggests that the extinction dust simultaneously obscures the accretion disk, the broad emission-line region, and the hot dust from the inner edge of the torus. It is possible that the dust obscuring the AGN structures is the dusty torus itself. Furthermore, the Cloudy analysis of the He i* λ 10830 absorption lines proposes the distance of the absorption materials to be the extend scale of the torus, which greatly increases probabilities of the obscure and absorption materials being the dusty torus.

  19. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

    Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Wang, Junfeng [Department of Astronomy, Physics Building, Xiamen University Xiamen, Fujian, 361005 (China); Storchi-Bergmann, Thaisa, E-mail: walter.maksym@cfa.harvard.edu [Departamento de Astronomia, Universidade Federal do Rio Grande do Sul, IF, CP 15051, 91501-970 Porto Alegre, RS (Brazil)

    2017-07-20

    The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.

  20. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

    Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa

    2017-07-01

    The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O III], [S II], and Hα, as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ˜10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include Hα evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.

  1. CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging

    Maksym, W. Peter; Fabbiano, Giuseppina; Elvis, Martin; Karovska, Margarita; Paggi, Alessandro; Raymond, John; Wang, Junfeng; Storchi-Bergmann, Thaisa

    2017-01-01

    The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra 's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images and compare them with Hubble Space Telescope narrow-line images of [O iii], [S ii], and H α , as well as previously unpublished mid-ultraviolet (MUV) images. The X-rays provide unprecedented evidence that the S-shaped arms that envelope the nuclear radio outflows extend only ≲0.″2 (≲50 pc) across. The high-resolution multiwavelength data suggest that the extended narrow-line region is a complex multiphase structure in the circumnuclear interstellar medium (ISM). Its ionization structure is highly stratified with respect to outflow-driven bubbles in the bicone and varies dramatically on scales of ∼10 pc. Multiple findings show likely contributions from shocks to the feedback in regions where radio outflows from the AGN most directly influence the ISM. These findings include H α evidence for gas compression and extended MUV emission and are in agreement with existing STIS kinematics. Extended filamentary structure in the X-rays and optical suggests the presence of an undetected plasma component, whose existence could be tested with deeper radio observations.

  2. Microsputterer with integrated ion-drag focusing for additive manufacturing of thin, narrow conductive lines

    Kornbluth, Y. S.; Mathews, R. H.; Parameswaran, L.; Racz, L. M.; Velásquez-García, L. F.

    2018-04-01

    We report the design, modelling, and proof-of-concept demonstration of a continuously fed, atmospheric-pressure microplasma metal sputterer that is capable of printing conductive lines narrower than the width of the target without the need for post-processing or lithographic patterning. Ion drag-induced focusing is harnessed to print narrow lines; the focusing mechanism is modelled via COMSOL Multiphysics simulations and validated with experiments. A microplasma sputter head with gold target is constructed and used to deposit imprints with minimum feature sizes as narrow as 9 µm, roughness as small as 55 nm, and electrical resistivity as low as 1.1 µΩ · m.

  3. Was the Narrow Line Seyfert 1 RGB J0044+193 ever radio loud?

    Maccarone, T.J.; Miller-Jones, J.C.A.; Fender, R.P.; Pooley, G.G.

    2005-01-01

    We show new radio data and a re-analysis of old data for the Narrow Line Seyfert 1 (NLSy1) galaxy RGB J0044+193. This galaxy has previously been suggested to be both radio loud, and highly variable in the radio. As most NLSy 1 galaxies are radio quiet, this was interpreted as possible evidence that

  4. The Size of Narrow Line Region and [OIII] Luminosity Analyzed from ...

    Abstract. In this work, we constructed a sample of 4002 quasars from. SDSS DR7 quasar catalogue to calculate the electron density and size of narrow line region. We find that the electron densities are ∼103/cm3, and the sizes are between 27 and 775 pc. We also find that, in the ionization cone, the sizes are tightly ...

  5. Bioanalytical Applications of Fluorescence Line-Narrowing and Non-Line-Narrowing Spectroscopy Interfaced with Capillary Electrophoresis and High-Performance Liquid Chromatography

    Roberts, Kenneth Paul [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC) are widely used analytical separation techniques with many applications in chemical, biochemical, and biomedical sciences. Conventional analyte identification in these techniques is based on retention/migration times of standards; requiring a high degree of reproducibility, availability of reliable standards, and absence of coelution. From this, several new information-rich detection methods (also known as hyphenated techniques) are being explored that would be capable of providing unambiguous on-line identification of separating analytes in CE and HPLC. As further discussed, a number of such on-line detection methods have shown considerable success, including Raman, nuclear magnetic resonance (NMR), mass spectrometry (MS), and fluorescence line-narrowing spectroscopy (FLNS). In this thesis, the feasibility and potential of combining the highly sensitive and selective laser-based detection method of FLNS with analytical separation techniques are discussed and presented. A summary of previously demonstrated FLNS detection interfaced with chromatography and electrophoresis is given, and recent results from on-line FLNS detection in CE (CE-FLNS), and the new combination of HPLC-FLNS, are shown.

  6. Relativistic jets in narrow-line Seyfert 1 galaxies. New discoveries and open questions

    D’Ammando F.

    2013-12-01

    Full Text Available Before the launch of the Fermi satellite only two classes of AGNs were known to produce relativistic jets and thus emit up to the γ-ray energy range: blazars and radio galaxies, both hosted in giant elliptical galaxies. The first four years of observations by the Large Area Telescope on board Fermi confirmed that these two are the most numerous classes of identified sources in the extragalactic γ-ray sky, but the discovery of γ-ray emission from 5 radio-loud narrow-line Seyfert 1 galaxies revealed the presence of a possible emerging third class of AGNs with relativistic jets. Considering that narrow-line Seyfert 1 galaxies seem to be typically hosted in spiral galaxy, this finding poses intriguing questions about the nature of these objects, the onset of production of relativistic jets, and the cosmological evolution of radio-loud AGN. Here, we discuss the radio-to-γ-rays properties of the γ-ray emitting narrow-line Seyfert 1 galaxies, also in comparison with the blazar scenario.

  7. An extreme Fe II emitter the narrow line quasar PHL 1092

    Bergeron, J

    1980-01-01

    A search for Fe II emission in a sample of radio-quiet quasars has revealed the outstanding properties of PHL 1092. Intense Fe II lines dominate the entire spectrum, and the Fe II UV multiplets are nearly as strong as the optical ones. In contrast the extreme weakness of the Balmer and Mg II lines is striking. For the first time, Fe I lines are identified in an extra-galactic object. The lines are narrow, with a FWHM of 1300 km s/sup -1/. The presence of Fe II UV lines and Fe I lines from the ground state requires moderate column densities. However Fe/sup 0/ can exist only in a region completely shielded from the UV continuum. The weakness of Mg II and H beta relative to Fe II lines is best explained by their thermalization. The emitting region is of high electron density n/sub e/ approximately=10/sup 12/ cm/sup -3/, low temperature T approximately=10000K, and has an optical depth in the Fe II UV lines tau /sub UV/ approximately=10/sup 3/-10/sup 4/. It is speculated that for higher densities all the lines wou...

  8. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    Shapovalova, A. I.; Burenkov, A. N.; Popović, L. Č.; Kovačević, J.; Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L.; Ilić, D.; Kovačević, A.; Kollatschny, W.; Bochkarev, N. G.; León-Tavares, J.; Mercado, A.; Benítez, E.; Dultzin, D.; De la Fuente, E.

    2012-01-01

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted Hα, Hβ, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the Hβ and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F max /F min ) of Ark 564 is between 1.5 for Hα and 1.8 for the Fe II lines. The correlation between the Fe II and Hβ flux variations is of higher significance than that of Hα and Hβ (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  9. NMR imaging of solids with multiple-pulse line narrowing and radiofrequency gradients

    Werner, M.H.

    1993-01-01

    The usual methods of magnetic resonance imaging fail in rigid solids due to the line-shape contributions of dipolar coupling, chemical shift dispersion and anisotropy, and bulk magnetic susceptibility. This dissertation presents a new method of solid-stage imaging by nuclear magnetic resonance which averages away these contributions with multiple-pulse line-narrowing and encodes spatial information with pulsed radiofrequency field gradients. This method is closely related to simultaneously developed methods utilizing pulsed DC gradients, and offers similar improvements in sensitivity and resolution. The advantage of rf gradients is that they can be rapidly switched without inducing eddy currents in the probe or the magnet. In addition, the phases and amplitudes of the rf gradients can be switched by equipment which is already part of an NMR spectrometer capable of solid-state spectroscopy. The line-narrowing and gradient pulses originate in separate rf circuits tuned to the same frequency. Interactions between the circuits have been minimized by a method of active Q-switching which employs PIN diodes in the matching networks of these circuits. Both one- and two-dimensional images are presented. The latter are obtained by a novel method in which the two dimensions of imaging transverse to the static magnetic field are encoded by two orthogonal components of a single rf gradient. A π/2 phase shift of the rf phase relative to that of the line-narrowing pulses selects one component or the other. This arrangement allows the solid-state analogs of versatile imaging sequences based on Fourier imaging and eliminates the need for sample rotation and back-projection methods. Coherent averaging theory is used to analyze this imaging technique and exact numerical simulations on several coupled spins are discussed. These lend insight to the residual linewidth and its dependence on pixel position as well as to the range of applicability of this technique

  10. Imaging spectrophotometry of ionized gas in NGC 1068. I - Kinematics of the narrow-line region

    Cecil, Gerald; Bland, Jonathan; Tully, R. Brent

    1990-01-01

    The kinematics of collisionally excited forbidden N II 6548, 6583 across the inner 1 arcmin diameter of the nearby Seyfert galaxy NGC 1068 is mapped using an imaging Fabry-Perot interferometer and low-noise CCD. The stack of monochromatic images, which spatially resolved the high-velocity gas, was analyzed for kinematic and photometric content. Profiles agree well with previous long-slit work, and their complete spatial coverage makes it possible to constrain the gas volume distribution. It is found that the narrow-line region is distributed in a thick center-darkened, line-emitting cylinder that envelopes the collimated radio jet. Three distinct kinematic subsystems, of which the cylinder is composed, are discussed in detail. Detailed behavior of the emission-line profiles, at the few points in the NE quadrant with simple kinematics, argues that the ionized gas develops a significant component of motion perpendicular to the jet axis.

  11. CONSTRAINING JET PRODUCTION SCENARIOS BY STUDIES OF NARROW-LINE RADIO GALAXIES

    Sikora, Marek [Nicolaus Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw (Poland); Stasinska, Grazyna [LUTH, Observatoire de Paris, CNRS, Universite Paris Diderot, Place Jules Janssen, F-92190 Meudon (France); Koziel-Wierzbowska, Dorota [Astronomical Observatory, Jagiellonian University, ul. Orla 171, 30-244 Krakow (Poland); Madejski, Greg M. [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305 (United States); Asari, Natalia V., E-mail: sikora@camk.edu.pl [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-03-01

    We study a large sample of narrow-line radio galaxies (NLRGs) with extended radio structures. Using 1.4 GHz radio luminosities L {sub 1.4}, narrow optical emission line luminosities L {sub [OIII]} and L{sub H{sub {alpha}}}, as well as black hole masses M {sub BH} derived from stellar velocity dispersions measured from the optical spectra obtained with the Sloan Digital Sky Survey, we find that (1) NLRGs cover about four decades of the Eddington ratio, {lambda} {identical_to} L {sub bol}/L {sub Edd}{proportional_to}L {sub line}/M {sub BH}; (2) L {sub 1.4}/M {sub BH} strongly correlates with {lambda}; and (3) radio loudness, R{identical_to}L{sub 1.4}/L{sub line}, strongly anti-correlates with {lambda}. A very broad range of the Eddington ratio indicates that the parent population of NLRGs includes both radio-loud quasars (RLQs) and broad-line radio galaxies (BLRGs). The correlations they obey and their high jet production efficiencies favor a jet production model which involves the so-called magnetically choked accretion scenario. In this model, production of the jet is dominated by the Blandford-Znajek mechanism, and the magnetic fields in the vicinity of the central black hole are confined by the ram pressure of the accretion flow. Since large net magnetic flux accumulated in central regions of the accretion flow required by the model can take place only via geometrically thick accretion, we speculate that the massive, 'cold' accretion events associated with luminous emission-line active galactic nucleus can be accompanied by an efficient jet production only if preceded by a hot, very sub-Eddington accretion phase.

  12. NARROW-LINE-WIDTH UV BURSTS IN THE TRANSITION REGION ABOVE SUNSPOTS OBSERVED BY IRIS

    Hou, Zhenyong; Huang, Zhenghua; Xia, Lidong; Li, Bo; Madjarska, Maria S.; Fu, Hui; Mou, Chaozhou; Xie, Haixia, E-mail: z.huang@sdu.edu.cn, E-mail: xld@sdu.edu.cn [Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences, Shandong University, Weihai, 264209 Shandong (China)

    2016-10-01

    Various small-scale structures abound in the solar atmosphere above active regions, playing an important role in the dynamics and evolution therein. We report on a new class of small-scale transition region structures in active regions, characterized by strong emissions but extremely narrow Si iv line profiles as found in observations taken with the Interface Region Imaging Spectrograph (IRIS). Tentatively named as narrow-line-width UV bursts (NUBs), these structures are located above sunspots and comprise one or multiple compact bright cores at sub-arcsecond scales. We found six NUBs in two data sets (a raster and a sit-and-stare data set). Among these, four events are short-lived with a duration of ∼10 minutes, while two last for more than 36 minutes. All NUBs have Doppler shifts of 15–18 km s{sup −1}, while the NUB found in sit-and-stare data possesses an additional component at ∼50 km s{sup −1} found only in the C ii and Mg ii lines. Given that these events are found to play a role in the local dynamics, it is important to further investigate the physical mechanisms that generate these phenomena and their role in the mass transport in sunspots.

  13. Direct HST Dust Lane Detection in Powerful Narrow-Line Radio Galaxies

    Ramírez, Edgar A.; Aretxaga, Itziar [Instituto Nacional de Astrofísica, Óptica y Electrónica, Puebla (Mexico); Tadhunter, Clive N. [Department of Physics and Astronomy, University of Sheffield, Sheffield (United Kingdom); Lopez-Rodriguez, Enrique [NASA Ames Research Center, SOFIA Science Center, SOFIA/USRA, Mountain View, CA (United States); Department of Astronomy, University of Texas at Austin, Austin, TX (United States); McDonald Observatory, University of Texas at Austin, Austin, TX (United States); Packham, Chris, E-mail: e.ramirez@inaoep.mx [Department of Physics and Astronomy, University of Texas at San Antonio, San Antonio, TX (United States); National Astronomical Observatory of Japan, Tokyo (Japan)

    2017-11-22

    We present the analysis of near-infrared Hubble Space Telescope imaging of 10 Fanaroff Riley II powerful radio galaxies at low redshift (0.03 < z < 0.11) optically classified as narrow-line radio galaxies. The photometric properties of the host galaxy are measured using galfit, and compared with those from the literature. Our high resolution near-infrared observations provide new and direct information on the central kpc-scale dust lanes in our sample that could be connected to the pc-scale torus structure. Moreover, analyzing the infrared spectrograph Spitzer spectra of our sample, we suggest properties of the dust size of the torus.

  14. SPECTRAL OPTICAL MONITORING OF THE NARROW-LINE SEYFERT 1 GALAXY Ark 564

    Shapovalova, A. I.; Burenkov, A. N. [Special Astrophysical Observatory of the Russian AS, Nizhnij Arkhyz, Karachaevo-Cherkesia 369167 (Russian Federation); Popovic, L. C.; Kovacevic, J. [Astronomical Observatory, Volgina 7, 11160 Belgrade 74 (Serbia); Chavushyan, V. H.; Valdes, J. R.; Torrealba, J.; Carrasco, L. [Instituto Nacional de Astrofisica, Optica y Electronica, Apartado Postal 51-216, 72000 Puebla (Mexico); Ilic, D.; Kovacevic, A. [Isaac Newton Institute of Chile, Yugoslavia Branch, Belgrade (Serbia); Kollatschny, W. [Institut fuer Astrophysik, Georg-August-Universitaet, Goettingen (Germany); Bochkarev, N. G. [Sternberg Astronomical Institute, Moscow (Russian Federation); Leon-Tavares, J. [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FIN-02540 Kylmaelae (Finland); Mercado, A. [Universidad Politecnica de Baja California, Av. de la Industria 291, 21010 Mexicali, B.C. (Mexico); Benitez, E.; Dultzin, D. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-264, Mexico, D.F. 04510 (Mexico); De la Fuente, E., E-mail: ashap@sao.ru [Instituto de Astronomia y Meteorologia, Dpto. de Fisica CUCEI, Universidad de Guadalajara, Av. Vallarta 2602, 44130 Guadalajara, Jalisco (Mexico)

    2012-09-15

    We present the results of a long-term (1999-2010) spectral optical monitoring campaign of the active galactic nucleus (AGN) Ark 564, which shows a strong Fe II line emission in the optical. This AGN is a narrow-line Seyfert 1 (NLS1) galaxy, a group of AGNs with specific spectral characteristics. We analyze the light curves of the permitted H{alpha}, H{beta}, optical Fe II line fluxes, and the continuum flux in order to search for a time lag between them. Additionally, in order to estimate the contribution of iron lines from different multiplets, we fit the H{beta} and Fe II lines with a sum of Gaussian components. We find that during the monitoring period the spectral variation (F{sub max}/F{sub min}) of Ark 564 is between 1.5 for H{alpha} and 1.8 for the Fe II lines. The correlation between the Fe II and H{beta} flux variations is of higher significance than that of H{alpha} and H{beta} (whose correlation is almost absent). The permitted-line profiles are Lorentzian-like and do not change shape during the monitoring period. We investigate, in detail, the optical Fe II emission and find different degrees of correlation between the Fe II emission arising from different spectral multiplets and the continuum flux. The relatively weak and different degrees of correlations between permitted lines and continuum fluxes indicate a rather complex source of ionization of the broad-line emission region.

  15. PERSPECTIVES OF UKRAINIAN RAILWAY TOURISM DEVELOPMENT ON NARROW-GAUGE LINES OF ZAKARPATTIA

    V. G. Kuznetsov

    2015-07-01

    Full Text Available Purpose.The purpose of the paper is: (1 the definition of perspectives development of Ukrainian railway tourism on the narrow gauge lines of Zakarpattia; 2 technical condition analysis of Borzhava narrow gauge railway for the project to restore the effective functioning of mountain railways track, width 750 mm in the Carpathian region, with the possibility of their accession to the distributed travel network; 3 the study of the modern state and tendencies of development of tourist industry of Ukraine and the passenger economy of national railways; 4 clarification of the role and place of the railway tourism in the transportation system. Methodology. The expert group has carried out field inspections and field investigations of facilities track facilities and passenger infrastructure, rolling stock and ancillary industries involved in the functioning narrow-gauge railway. It was estimated the overall technical condition of the railway track and engineering structures section of narrow-gauge Railways in the Carpathian region. Findings. In the framework of on-site examinations of the expert group found that the objects of tracks, passenger and freight infrastructure, rolling stock and ancillary industries involved in the operation of narrow-gauge Railways are in poor condition and require significant updates and major repairs. But the routes of passenger trains remain fit for participation in the project of development of railway tourism of Ukraine Originality. For the first time the state of the narrow-gauge railway for further implementation of the project on the development of rail tourism in Ukraine was realized. The analysis of foreign experience of organization of railway tourism has been carried out. The modern state and tendencies of development of tourist industry of Ukraine was studied, the factors of competitiveness of rail transport for providing tourist transport in Ukraine were identified and systematized.Practical value. The recovery

  16. Narrow absorption lines with two observations from the Sloan Digital Sky Survey

    Chen, Zhi-Fu; Gu, Qiu-Sheng; Chen, Yan-Mei; Cao, Yue

    2015-07-01

    We assemble 3524 quasars from the Sloan Digital Sky Survey (SDSS) with repeated observations to search for variations of the narrow C IV λ λ 1548,1551 and Mg II λ λ 2796,2803 absorption doublets in spectral regions shortward of 7000 Å in the observed frame, which corresponds to time-scales of about 150-2643 d in the quasar rest frame. In these quasar spectra, we detect 3580 C IV absorption systems with zabs = 1.5188-3.5212 and 1809 Mg II absorption systems with zabs = 0.3948-1.7167. In term of the absorber velocity (β) distribution in the quasar rest frame, we find a substantial number of C IV absorbers with β Hacker et al. However, in our Mg II absorption sample, we find that neither shows variable absorption with confident levels of >4σ for λ2796 lines and >3σ for λ2803 lines.

  17. Anisotropic ionizing radiation in Seyfert galaxies. I - The extended narrow-line region in Markarian 573

    Tsvetanov, Zlatan; Walsh, J. R.

    1992-01-01

    The morphology, kinematics, and ionization state of the nuclear extended narrow-line region (ENLR) of the Seyfert 2 galaxy Mrk 573 are studied using narrow-band images of a grid of long-slit spectra. The entire ENLR is mapped spectroscopically, and velocity structure is studied. The velocity field map shows a typical galactic rotation picture with some important deviations. A simple geometric model, in accordance with the 'unified schemes', is employed to study the effects of various parameters of the observed picture. The best match is achieved when a biconical radiation field illuminates the ISM of the host galaxy that takes part in a normal galaxy rotation but also has radial motions close to the nucleus. The emission-line images reveal an ENLR elongated along the radio axis in the northwest-southeast direction, but a map of the flux ratio forbidden O III 5007/(H-alpha + forbidden N II) shows a different structure, with the highest excitation peak offset by about 4 arcsec along the radio axis to the southeast.

  18. ON THE APPARENT NARROWING OF RADIO RECOMBINATION LINES AT HIGH PRINCIPAL QUANTUM NUMBERS

    Alexander, J.; Gulyaev, S.

    2012-01-01

    We critically analyze the Bell et al. findings on 'anomalous' widths of high-order hydrogen radio recombination lines in the Orion Nebula at 6 GHz. We review their method of modified frequency switching and show that the way this method is used for large Δn is not optimal and can lead to misinterpretation of measured spectral line parameters. Using a model of the Orion Nebula, conventional broadening theory, and Monte Carlo simulation, we determine a transition zone n = 224, ..., 241 (Δn = 11, ..., 14), where measurement errors grow quickly with n and become comparable with the measurement values themselves. When system noise and spectrum channelization are accounted for, our simulation predicts 'processed' line narrowing in the transition zone similar to that reported by Bell et al. We find good agreement between our simulation results and their findings, both in line temperatures and widths. We conclude, therefore, that Bell et al.'s findings do not indicate a need to revise Stark broadening theory.

  19. Time-dependent narrow emission-line profiles of quasars and active galactic nuclei

    Capriotti, E.R.; Foltz, C.B.

    1982-01-01

    The narrow-line emitting regions of quasars and active nuclei of galaxies are assumed to consist of material undergoing gravitational infall due to acceleration by centrally located mass concentrations. Two cases are considered. In one, the material is assumed to be in the form of optically thick, similar clouds which emit line radiation monochromatically, isotropically and in inverse proportion to the square of the distance from the center of the system. In the other case, the material is assumed to be homogeneous, isothermal and to have the same ionization structure everywhere. The material is assumed to be excited by an ionizing continuum created ty a supernova-like outburst of radiation. Line profiles are computed for various combinations of epoch after outburst, continuum decay times, and spectral resolution. The computed profiles are clearly asymmetric to the blue of the profile peak and for certain combinations of epoch and decay time, clearly asymmetric to the blue of line center. The computed profiles compare well with many observed [O III] profiles

  20. Extreme Gaseous Outflows in Radio-Loud Narrow-Line Seyfert 1 Galaxies

    Komossa, S.; Xu, D. W.; Wagner, A. Y.

    2018-04-01

    We present four radio-loud NLS1 galaxies with extreme emission-line shifts, indicating radial outflow velocities of the ionized gas of up to 2450 km/s, above the escape velocity of the host galaxies. The forbidden lines show strong broadening, up to 2270 km/s. An ionization stratification (higher line shift at higher ionization potential) implies that we see a large-scale outflow rather than single, localized jet-cloud interactions. Similarly, the paucity of zero-velocity [OIII]λ5007 emitting gas implies the absence of a second narrow-line region (NLR) component at rest, and therefore a large part of the high-ionization NLR is affected by the outflow. Given the radio loudness of these NLS1 galaxies, the observations are consistent with a pole on view onto their central engines, so that the effects of polar outflows are maximized. In addition, a very efficient driving mechanism is required, to reach the high observed velocities. We explore implications from recent hydrodynamic simulations of the interaction between fast winds or jets with the large-scale NLR. Overall, the best agreement with observations (and especially the high outflow speeds of the [NeV] emitting gas) can be reached if the NLS1 galaxies are relatively young sources with lifetimes not much exceeding 1 Myr. These systems represent sites of strong feedback at NLR scales at work, well below redshift one.

  1. PHYSICAL CONDITIONS IN THE INNER NARROW-LINE REGION OF THE SEYFERT 2 GALAXY MARKARIAN 573

    Kraemer, S. B.; Trippe, M. L.; Crenshaw, D. M.; Fischer, T. C.; Melendez, M.; Schmitt, H. R.

    2009-01-01

    We have examined the physical conditions within a bright emission-line knot in the inner narrow-line region (NLR) of the Seyfert 2 galaxy Mrk 573 using optical spectra and photoionization models. The spectra were obtained with the Hubble Space Telescope/Space Telescope Imaging Spectrograph, through the 0.''2 x 52.''0 slit, at a position angle of -71. 0 2, with the G430L and G750M gratings. Comparing the spatial emission-line profiles, we found [Fe X] λ 6734 barely resolved, [O III] λ5007 centrally peaked, but broader than [Fe X], and [O II] λ3727 the most extended. Spectra of the central knot were extracted from a region 1.''1 in extent, corresponding to the full width at zero intensity in the cross-dispersion direction, of the knot. The spectra reveal that [Fe X] is broader in velocity width and blueshifted compared with lines from less ionized species. Our estimate of the bolometric luminosity indicates that the active galactic nucleus (AGN) is radiating at or above its Eddington luminosity, which is consistent with its identification as a hidden Narrow-Line Seyfert 1. We were able to successfully match the observed emission-line ratios with a three-component photoionization model. Two components, one to account for the [O III] emission and another in which the [Fe X] arises, are directly ionized by the AGN, while [O II] forms in a third component, which is ionized by a heavily absorbed continuum. Based on our assumed ionizing continuum and the model parameters, we determined that the two directly ionized components are ∼55 pc from the AGN. We have found similar radial distances for the central knots in the Seyfert 2 galaxies Mrk 3 and NGC 1068, but much smaller radial distances for the inner NLR in the Seyfert 1 galaxies NGC 4151 and NGC 5548. Although in general agreement with the unified model, these results suggest that the obscuring material in Seyfert galaxies extends out to at least tens of parsecs from the AGN.

  2. Fluorescence line-narrowing studies of rare earths in disordered solids

    Hall, D.W.

    1982-01-01

    This dissertation is made up of two experimental studies dealing with apparently diverse topics within the subject of rare earths (RE) in solids. The first study, described in Part II, concerns the vibrations of a disordered host material about an optically active rare-earth ion as manifested by vibrationally-assisted-electronic, or vibronic transitions. Part III of the dissertation describes an investigation of the influence of site anisotropy on the purely electronic, laser transition of Nd 3+ in glass. These two studies are bound together by the common experimental technique of laser-induced fluorescence line narrowing (FLN). By exciting fluorescence with monochromatic light of well-characterized polarization, one may select and observe the response of a single subset of the optically active ions and obtain information that is usually masked by the inhomogeneous nature of disordered solids

  3. Investigations of glass structure using fluorescence line narrowing and moleuclar dynamics simulations

    Weber, M.J.; Brawer, S.A.

    1982-01-01

    The local structure at individual ion sites in simple and multicomponent glasses is simulated using methods of molecular dynamics. Computer simulations of fluoroberyllate glasses predict a range of ion separations and coordination numbers that increases with increasing complexity of the glass composition. This occurs at both glass forming and glass modifying cation sites. Laser-induced fluorescence line-narrowing techniques provide a unique probe of the local environments of selected subsets of ions and are used to measure site to site variations in the electronic energy levels and transition probabilities of rare earth ions. These and additional results from EXAFS, neutron and x-ray diffraction, and NMR experiments are compared with simulated glass structures

  4. A catapult model for the narrow-line region in Seyferts and radio galaxies

    Smith, M.D.

    1984-01-01

    The kinematics and stability of clouds falling radially into a supersonic wind are studied. A critical parameter is found, the ejection coefficient, which separates clouds which continue to gravitate inwards from those which are catapulted out by the ram pressure of the wind. This leads to a maximum size for ejected clouds. The clouds are partially broken up by fluid dynamic instabilities and the fragments expelled with enhanced velocities. This model is applied to the narrow-line region of Seyferts and radio galaxies. A quasi-steady picture may be established for the wind-ambient medium interaction zone. The wind is shocked and escapes through jets or bubbles; the ambient medium cools, forming the clouds which gravitate inwards. (author)

  5. Variable blurred reflection in the narrow-line Seyfert 1 galaxy Mrk 493

    Bonson, K.; Gallo, L. C.; Wilkins, D. R.; Fabian, A. C.

    2018-04-01

    We examine a 200 ks XMM-Newton observation of the narrow-line Seyfert 1 galaxy Mrk 493. The active galaxy was half as bright as in a previous 2003 snapshot observation and the current lower flux enables a study of the putative reflection component in detail. We determine the characteristics of the 2015 X-ray continuum by first analyzing the short-term variability using model-independent techniques. We then continue with a time-resolve analysis including spectral fitting and modelling the fractional variability. We determine that the variability arises from changes in the amount of primary flux striking the accretion disk, which induces changes in the ionization parameter and flux of the blurred reflection component. The observations seem consistent with the picture that the primary source is of roughly constant brightness and that variations arise from changes in the degree of light bending happening in the vicinity of the supermassive black hole.

  6. Generation of narrow-band polarization-entangled photon pairs at a rubidium D1 line

    Tian Long; Li Shujing; Yuan Haoxiang; Wang Hai

    2016-01-01

    Using the process of cavity-enhanced spontaneous parametric down-conversion (SPDC), we generate a narrow-band polarization-entangled photon pair resonant on the rubidium (Rb) D1 line (795 nm). The degenerate single-mode photon pair is selected by multiple temperature controlled etalons. The linewidth of generated polarization-entangled photon pairs is 15 MHz which matches the typical atomic memory bandwidth. The measured Bell parameter for the polarization-entangled photons S = 2.73 ± 0.04 which violates the Bell-CHSH inequality by ∼18 standard deviations. The presented entangled photon pair source could be utilized in quantum communication and quantum computing based on quantum memories in atomic ensemble. (author)

  7. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    Suh, Myungkoo [Iowa State Univ., Ames, IA (United States)

    1995-12-06

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7β, 8α-dihydoxy-9α, l0α-epoxy-7,8,9, 10-tetrahydrobenzo[α]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, (-)-trans-, (+)-cis- and (-)-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( ~25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant π-π stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G2 or G3 (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N2-dG in DNA isolated from the skin of mice treated topically with benzo[α]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N2-dG.

  8. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    Suh, Myungkoo.

    1995-01-01

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7β, 8α-dihydoxy-9α, l0α-epoxy-7,8,9, 10-tetrahydrobenzo[α]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, (-)-trans-, (+)-cis- and (-)-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( ∼ 25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant π-π stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G 2 or G 3 (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N 2 -dG in DNA isolated from the skin of mice treated topically with benzo[α]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N 2 -dG

  9. THE ROLE OF RADIATION PRESSURE IN THE NARROW LINE REGIONS OF SEYFERT HOST GALAXIES

    Davies, Rebecca L.; Dopita, Michael A.; Kewley, Lisa; Groves, Brent; Sutherland, Ralph; Hampton, Elise J.; Banfield, Julie [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Shastri, Prajval; Kharb, Preeti; Bhatt, Harish [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); Scharwächter, Julia [LERMA, Observatoire de Paris, PSL, CNRS, Sorbonne Universités, UPMC, F-75014 Paris (France); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Zaw, Ingyin [New York University (Abu Dhabi), 70 Washington Square S, New York, NY 10012 (United States); James, Bethan [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Srivastava, Shweta, E-mail: Rebecca.Davies@anu.edu.au [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India)

    2016-06-10

    We investigate the relative significance of radiation pressure and gas pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). We demonstrate that there exist two distinct types of starburst-active galactic nucleus (AGN) mixing curves on standard emission line diagnostic diagrams, which reflect the balance between gas pressure and radiation pressure in the ENLR. In two of the galaxies the ENLR is radiation pressure dominated throughout and the ionization parameter remains constant (log U ∼ 0). In the other two galaxies radiation pressure is initially important, but gas pressure becomes dominant as the ionization parameter in the ENLR decreases from log U ∼ 0 to −3.2 ≲ log U ≲ −3.4. Where radiation pressure is dominant, the AGN regulates the density of the interstellar medium on kiloparsec scales and may therefore have a direct impact on star formation activity and/or the incidence of outflows in the host galaxy to scales far beyond the zone of influence of the black hole. We find that both radiation pressure dominated and gas pressure dominated ENLRs are dynamically active with evidence for outflows, indicating that radiation pressure may be an important source of AGN feedback even when it is not dominant over the entire ENLR.

  10. Spectral properties of X-ray selected narrow emission line galaxies

    Romero-Colmenero, E.

    1998-03-01

    This thesis reports a study of the X-ray and optical properties of two samples of X-ray selected Narrow Emission Line Galaxies (NELGs), and their comparison with the properties of broad line Active Galactic Nuclei (AGN). One sample (18 NELGs) is drawn from the ROSAT International X-ray Optical Survey (RIXOS), the other (19 NELGs and 33 AGN) from the ROSAT UK Deep Survey. ROSAT multi-channel X-ray spectra have been extracted and fitted with power-law, bremsstrahlung and black body models for the brighter RIXOS sources. In most cases, power-law and bremsstrahlung models provide the best results. The average spectral energy index, alpha, of the RIXOS NELGs is 0.96 +/- 0.07, similar to that of AGN (alpha~1). For the fainter RIXOS NELGs, as well as for all the UK Deep Survey sources, counts in three spectral bands have been extracted and fitted with a power-law model, assuming the Galactic value for N_H. The brighter RIXOS sources demonstrated that the results obtained by these two different extraction and fitting procedures provide consistent results. Two average X-ray spectra, one for the NELGs and another for the AGN, were created from the UK Deep Survey sources. The power-law slope of the average NELG is alpha = 0.45 +/- 0.09, whilst that of the AGN is alpha = 0.96 +/- 0.03. ROSAT X-ray surveys have shown that the fractional surface density of NELGs increases with respect to AGN at faint fluxes (case for NELGs to be major contributors to the XRB at the fainter fluxes. The analysis of optical spectroscopy, obtained on La Palma and Hawaii, shows that NELGs form a very heterogeneous group, made up of a mixture of Seyfert 2, LINER and HII-region like galaxies. Seyfert 2 galaxies are found to possess in general the steepest X-ray slopes. Ways to explain this in the context of the unified model of AGN are discussed. The FWHM of some emission lines (Halpha, Hbeta, [NII]) in the NELGs appears to increase with steepening X-ray spectral slope. In the case of the Balmer lines

  11. Fluorescence line-narrowing studies of Nd:glass laser materials

    Riseberg, L.A.; Brecher, C.

    The increasing importance of Nd glass lasers in laser fusion technology has emphasized the inadequacy in the understanding of the optical properties of rare earth ions in glasses. Indeed, it has been difficult to generate models for the performance of these devices, and the selection of host glasses could be done by little more than a trial-and-error approach. The technique of laser-induced fluorescence line-narrowing developed within the last few years provides a new and powerful tool for the study of these systems. In this technique, a laser excites within the inhomogeneously broadened absorption bands a selected subgroup of the ions in the system, namely those whose absorption energy is resonant with the laser. If the excitation does not migrate among the entire collection of ions prior to fluorescence, the fluorescence that is observed is only from the group that was excited and is narrowed. This permits the selective study of classes of ion sites within the ensemble. The concept is indicated schematically. By the use of a tunable laser, such as a dye laser, it is possible to vary the class of sites, defined by energy, that is excited and thereby study the important spectroscopic properties and their variations, unclouded by the averaging that occurs under excitation of the entire system. Furthermore, it is then possible to use the spectroscopic information to infer a description of the variation of the microscopic environment, and a rationalization of the effects of compositional changes. Use of a pulsed dye laser and time-resolved detection permits the study of the dynamics, including, for example, the energy transfer among ions of different energies within the inhomogeneously-broadened spectrum. The goal of this project has been to apply such studies to glasses of interest to glass laser technology, providing information for device modeling, and establishing design criteria for glass selection

  12. The peculiar radio-loud narrow line Seyfert 1 galaxy 1H 0323+342

    Paliya, Vaidehi S.; Stalin, C. S. [Indian Institute of Astrophysics, Block-II, Koramangala, Bangalore-560034 (India); Sahayanathan, S. [Astrophysical Science Division, Bhabha Atomic Research Center, Mumbai-400085 (India); Parker, M. L.; Fabian, A. C. [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom); Anjum, Ayesha [Department of Physics, Christ University, Bangalore-560029 (India); Pandey, S. B., E-mail: vaidehi@iiap.res.in [Aryabhatta Research Institute of Observational Sciences, Manora peak, Nainital-263129 (India)

    2014-07-10

    We present a multiwavelength study of the radio-loud narrow-line Seyfert 1 galaxy (NLSy1) 1H 0323+342, detected by the Fermi Gamma-Ray Space Telescope. Multiband light curves show many orphan X-ray and optical flares having no corresponding γ-ray counterparts. Such anomalous variability behavior can be due to different locations of the emission region from the central source. During a large flare, a γ-ray flux doubling timescale as small as ∼3 hr is noticed. We built spectral energy distributions (SEDs) during different activity states and modeled them using a one-zone leptonic model. The shape of the optical/UV component of the SEDs is dominated by accretion disk emission in all the activity states. In the X-ray band, significant thermal emission from the hot corona is inferred during quiescent and first flaring states; however, during subsequent flares, the nonthermal jet component dominates. The γ-ray emission in all the states can be well explained by inverse-Compton scattering of accretion disk photons reprocessed by the broad-line region. The source showed violent intra-night optical variability, coinciding with one of the high γ-ray activity states. An analysis of the overall X-ray spectrum fitted with an absorbed power-law plus relativistic reflection component hints at the presence of an Fe Kα line and returns a high black hole spin value of a = 0.96 ± 0.14. We argue that 1H 0323+342 possesses dual characteristics, akin to both flat-spectrum radio quasars (FSRQs) and radio-quiet NLSy1 galaxies, though at a low jet power regime compared to powerful FSRQs.

  13. KILOPARSEC-SCALE RADIO STRUCTURES IN NARROW-LINE SEYFERT 1 GALAXIES

    Doi, Akihiro; Kino, Motoki [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Nagira, Hiroshi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Kawakatu, Nozomu [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571 (Japan); Nagai, Hiroshi [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Asada, Keiichi, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2012-11-20

    We report the finding of kiloparsec (kpc)-scale radio structures in three radio-loud narrow-line Seyfert 1 (NLS1) galaxies from the Faint Images of the Radio Sky at Twenty-centimeters of the Very Large Array, which increases the number of known radio-loud NLS1s with kpc-scale structures to six, including two {gamma}-ray-emitting NLS1s (PMN J0948+0022 and 1H 0323+342) detected by the Fermi Gamma-ray Space Telescope. The detection rate of extended radio emissions in NLS1s is lower than that in broad-line active galactic nuclei (AGNs) with a statistical significance. We found both core-dominated (blazar-like) and lobe-dominated (radio-galaxy-like) radio structures in these six NLS1s, which can be understood in the framework of the unified scheme of radio-loud AGNs that considers radio galaxies as non-beamed parent populations of blazars. Five of the six NLS1s have (1) extended radio luminosities suggesting jet kinetic powers of {approx}> 10{sup 44} erg s{sup -1}, which is sufficient to make jets escape from hosts' dense environments; (2) black holes of {approx}> 10{sup 7} M {sub Sun }, which can generate the necessary jet powers from near-Eddington mass accretion; and (3) two-sided radio structures at kpc scales, requiring expansion rates of {approx}0.01c-0.3c and kinematic ages of {approx}> 10{sup 7} years. On the other hand, most typical NLS1s would be driven by black holes of {approx}< 10{sup 7} M {sub Sun} in a limited lifetime of {approx}10{sup 7} years. Hence, the kpc-scale radio structures may originate in a small window of opportunity during the final stage of the NLS1 phase just before growing into broad-line AGNs.

  14. In vivo imaging of a stable paramagnetic probe by pulsed-radiofrequency electron paramagnetic resonance spectroscopy

    Murugesan; Cook; Devasahayam

    1997-01-01

    , Recent advances in radiofrequency (RF) electronics have enabled the generation of pulses of the order of 10-50 ns. Such short pulses provide adequate spectral coverage for EPR studies at 300 MHz resonant frequency. Acquisition of free induction decays (FID) of paramagnetic species possessing...... inhomogeneously broadened narrow lines after pulsed excitation is feasible with an appropriate digitizer/averager. This report describes the use of time-domain RF EPR spectrometry and imaging for in vivo applications. FID responses were collected from a water-soluble, narrow line width spin probe within phantom...... samples in solution and also when infused intravenously in an anesthetized mouse. Using static magnetic field gradients and back-projection methods of image reconstruction, two-dimensional images of the spin-probe distribution were obtained in phantom samples as well as in a mouse. The resolution...

  15. MULTI-WAVELENGTH PROBES OF OBSCURATION TOWARD THE NARROW-LINE REGION IN SEYFERT GALAXIES

    Kraemer, S. B.; Schmitt, H.R.; Crenshaw, D. M.; Melendez, M.; Turner, T.J.; Guainazzi, M.; Mushotzky, R.F.

    2011-01-01

    We present a study of reddening and absorption toward the narrow line regions (NLRs) in active galactic nuclei (AGNs) selected from the Revised Shapley-Ames, 12 μm, and Swift/Burst Alert Telescope samples. For the sources in host galaxies with inclinations of b/a > 0.5, we find that the mean ratio of [O III] λ5007, from ground-based observations, and [O IV] 28.59 μm, from Spitzer/Infrared Spectrograph observations, is a factor of two lower in Seyfert 2s than Seyfert 1s. The combination of low [O III]/[O IV] and [O III] λ4363/λ5007 ratios in Seyfert 2s suggests more extinction of emission from the NLR than in Seyfert 1s. Similar column densities of dusty gas, N H ∼ several x 10 21 cm -2 , can account for the suppression of both [O III] λ5007 and [O III] λ4363, as compared to those observed in Seyfert 1s. Also, we find that the X-ray line O VII λ22.1 A is weaker in Seyfert 2s, consistent with absorption by the same gas that reddens the optical emission. Using a Hubble Space Telescope/Space Telescope Imaging Spectrograph slitless spectrum of the Seyfert 1 galaxy NGC 4151, we estimate that only ∼30% of the [O III] λ5007 comes from within 30 pc of the central source, which is insufficient to account for the low [O III]/[O IV] ratios in Seyfert 2s. If Seyfert 2 galaxies have similar intrinsic [O III] spatial profiles, the external dusty gas must extend further out along the NLR, perhaps in the form of nuclear dust spirals that have been associated with fueling flows toward the AGN.

  16. Fermi monitoring of radio-loud narrow-line Seyfert 1 galaxies

    Paliya, Vaidehi S.; Stalin, C. S.; Ravikumar, C. D.

    2015-01-01

    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein–Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

  17. Fermi monitoring of radio-loud narrow-line Seyfert 1 galaxies

    Paliya, Vaidehi S.; Stalin, C. S. [Indian Institute of Astrophysics, Block II, Koramangala, Bangalore-560034 (India); Ravikumar, C. D., E-mail: vaidehi@iiap.res.in [Department of Physics, University of Calicut, Malappuram-673635 (India)

    2015-02-01

    We present detailed analysis of the γ-ray flux variability and spectral properties of the five radio-loud narrow line Seyfert 1 (RL-NLSy1) galaxies, detected by the Large Area Telescope on board the Fermi Gamma-Ray Space Telescope, namely 1H 0323+342, SBS 0846+513, PMN J0948+0022, PKS 1502+036, and PKS 2004−447. The first three sources show significant flux variations, including the rapid variability of a few hours by 1H 0323+342. The average γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 shows deviation from a simple power-law (PL) behavior, whereas the PL model gives a better fit for the other three sources. The spectra of 1H 0323+342, SBS 0846+513, and PMN J0948+0022, which are in low, flaring, and moderately active states, respectively, show significant curvature. Such curvature in the γ-ray spectrum of 1H 0323+342 and PMN J0948+0022 could be due to the emission region located inside the broad line region (BLR) where the primary mechanism of the γ-ray emission is inverse-Compton (IC) scattering of BLR photons occurring in the Klein–Nishina regime. The γ-ray emission of SBS 0846+513 is explained by IC scattering of dusty torus photons, which puts the emission region outside the BLR and thus under the Thomson regime. Therefore, the observed curvature of SBS 0846+513 could be intrinsic to the particle energy distribution. The presence of curvature in the γ-ray spectrum and flux variability amplitudes of some of the RL-NLSy1 galaxies suggests that these sources could be akin to low/moderate jet power flat spectrum radio quasars.

  18. KILOPARSEC-SCALE JETS IN THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES

    Richards, Joseph L.; Lister, Matthew L., E-mail: jlr@purdue.edu [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2015-02-10

    We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array. We find all sources show two-sided, mildly core-dominated jet structures with diffuse lobes dominated by termination hotspots. These span 20–70 kpc with morphologies reminiscent of FR II radio galaxies, while the extended radio luminosities are intermediate between FR I and FR II sources. In two cases the structure is linear, while a 45° bend is apparent in the third. Very Long Baseline Array images at 7.6 GHz reveal parsec-scale jet structures, in two cases with extended structure aligned with the inner regions of the kiloparsec-scale jets. Based on this alignment, the ratio of the radio core–luminosity to the optical luminosity, the jet/counter-jet intensity and extension length ratios, and moderate core brightness temperatures (≲10{sup 10} K), we conclude these jets are mildly relativistic (β≲0.3, δ∼1−1.5) and aligned at moderately small angles to the line of sight (10–15°). The derived kinematic ages of ∼10{sup 6}–10{sup 7} yr are much younger than radio galaxies but comparable to other NLS1s. Our results increase the number of radio-loud NLS1s with known kiloparsec-scale extensions from 7 to 10 and suggest that such extended emission may be common, at least among the brightest of these sources.

  19. The Size-Luminosity Relationship of Quasar Narrow-Line Regions

    Dempsey, Ross; Zakamska, Nadia L.

    2018-04-01

    The presence of an active galactic nucleus (AGN) can strongly affect its host. Due to the copious radiative power of the nucleus, the effects of radiative feedback can be detected over the entire host galaxy and sometimes well into the intergalactic space. In this paper we model the observed size-luminosity relationship of the narrow-line regions (NLRs) of AGN. We model the NLR as a collection of clouds in pressure equilibrium with the ionizing radiation, with each cloud producing line emission calculated by Cloudy. The sizes of the NLRs of powerful quasars are reproduced without any free parameters, as long as they contain massive (105M⊙ to 107M⊙) ionization-bounded clouds. At lower AGN luminosities the observed sizes are larger than the model sizes, likely due to additional unmodeled sources of ionization (e.g., star formation). We find that the observed saturation of sizes at ˜10kpc which is observed at high AGN luminosities (Lion ≃ 1046erg/s) is naturally explained by optically thick clouds absorbing the ionizing radiation and preventing illumination beyond a critical distance. Using our models in combination with observations of the [O III]/IR ratio and the [O III] size - IR luminosity relationship, we calculate the covering factor of the obscuring torus (and therefore the type 2 fraction within the quasar population) to be f = 0.5, though this is likely an upper bound. Finally, because the gas behind the ionization front is invisible in ionized gas transitions, emission-based NLR mass calculations underestimate the mass of the NLR and therefore of the energetics of ionized-gas winds.

  20. Exploring the physics of the accretion and jet in nearby narrow-line Seyfert 1 galaxies

    Yao, Su; Qiao, Erlin; Wu, Xue-Bing; You, B.

    2018-06-01

    In this paper, we explore the physics of the accretion and jet in narrow-line Seyfert 1 (NLS1) galaxy. Specifically, we compile a sample composed of 16 nearby NLS1 with Lbol/LEdd ≳ 0.1. We investigate the mutual correlation between their radio luminosity LR, X-ray luminosity LX, optical luminosity L5100, and black hole mass MBH. By adopting partial correlation analysis, we find (1) a positive correlation between LX and MBH and (2) a weak positive correlation between LR and L5100. However, we don't find significant correlations between LR and LX or between LX and L5100 after considering the effect of the black hole mass, which leads to a finding that LX/LEdd is independent of L5100/LEdd. Interestingly, the findings that LX is correlated with MBH and LX/LEdd is not correlated with L5100/LEdd support that the X-ray emission is saturated with increasing \\dot{M} for Lbol/LEdd ≳ 0.1 in NLS1, which may be understood in the framework of slim disc scenario. Finally, we suggest that a larger NLS1 sample with high-quality radio and X-ray data is needed to further confirm this result in the future.

  1. A FANAROFF-RILEY TYPE I CANDIDATE IN NARROW-LINE SEYFERT 1 GALAXY Mrk 1239

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Hagiwara, Yoshiaki [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Inoue, Makoto, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

    2015-01-10

    We report finding kiloparsec-scale radio emissions aligned with parsec-scale jet structures in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 1239 using the Very Large Array and the Very Long Baseline Array. Thus, this radio-quiet NLS1 has a jet-producing central engine driven by essentially the same mechanism as that of other radio-loud active galactic nuclei (AGNs). Most of the radio luminosity is concentrated within 100 parsecs and overall radio morphology looks edge-darkened; the estimated jet kinetic power is comparable to Fanaroff-Riley Type I radio galaxies. The conversion from accretion to jet power appears to be highly inefficient in this highly accreting low-mass black hole system compared with that in a low-luminosity AGN with similar radio power driven by a sub-Eddington, high-mass black hole. Thus, Mrk 1239 is a crucial probe to the unexplored parameter spaces of central engines for a jet formation.

  2. SBS 0846+513: a New Gamma-ray Emitting Narrow-line Seyfert 1 Galaxy

    D'Ammando, F.; Orienti, M.; Finke, J.; Raiteri, C. M.; Angelakis, E.; Fuhrmann, L.; Giroletti, M.; Hovatta, T.; Max-Moerbeck, W.; Perkins, J. S.; hide

    2012-01-01

    We report Fermi-LAT observations of the radio-loud AGN SBS 0846+513 (z=0.5835), optically classified as a Narrow-Line Seyfert 1 galaxy, together with new and archival radio-to-X-ray data. The source was not active at ?-ray energies during the first two years of Fermi operation. A significant increase in activity was observed during 2010 October-2011 August. In particular a strong gamma-ray flare was observed in 2011 June reaching an isotropic ?-ray luminosity (0.1-300 GeV) of 1.0×10(sup 48) erg s(sup -1), comparable to that of the brightest flat spectrum radio quasars, and showing spectral evolution in gamma rays. An apparent superluminal velocity of (8.2+/-1.5)c in the jet was inferred from 2011-2012 VLBA images, suggesting the presence of a highly relativistic jet. Both the power released by this object during the flaring activity and the apparent superluminal velocity are strong indications of the presence of a relativistic jet as powerful as those of blazars. In addition, variability and spectral properties in radio and gamma-ray bands indicate blazar-like behaviour, suggesting that, except for some distinct optical characteristics, SBS 0846+513 could be considered as a young blazar at the low end of the blazar's black hole mass distribution.

  3. Distributed seeding for narrow-line width hard x-ray free-electron lasers

    Nguyen, Dinh Cong [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Anisimov, Petr Mikhaylovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Buechler, Cynthia Eileen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewellen, IV, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Marksteiner, Quinn R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-09-09

    We describe a new FEL line-narrowing technique called distributed seeding (DS), using Si(111) Bragg crystal monochromators to enhance the spectral brightness of the MaRIE hard X-ray freeelectron laser. DS differs from self-seeding in three important aspects. First, DS relies on spectral filtering of the radiation at multiple locations along the undulator, with a monochromator located every few power gain lengths. Second, DS performs filtering early in the exponential gain region before SASE spikes start to appear in the radiation longitudinal profile. Third, DS provides the option to select a wavelength longer than the peak of the SASE gain curve, which leads to improved spectral contrast of the seeded FEL over the SASE background. Timedependent Genesis simulations show the power-vs-z growth curves for DS exhibit behaviors of a seeded FEL amplifier, such as exponential growth region immediately after the filters. Of the seeding approaches considered, the two-stage DS spectra produce the highest contrast of seeded FEL over the SASE background and that the three-stage DS provides the narrowest linewidth with a relative spectral FWHM of 8 X 10-5 .

  4. Searches for H2O masers toward narrow-line Seyfert 1 galaxies

    Yoshiaki, Hagiwara; Doi, Akihiro; Hachisuka, Kazuya; Horiuchi, Shinji

    2018-05-01

    We present searches for 22 GHz H2O masers toward 36 narrow-line Seyfert 1 galaxies (NLS1s), selected from known NLS1s with vsys ≲ 41000 km s-1. Out of the 36 NLS1s in our sample, 11 have been first surveyed in our observations, while the observations of other NLS1s were previously reported in literature. In our survey, no new water maser source from NLS1s was detected at the 3σ rms level of 8.4 mJy to 144 mJy, which depends on different observing conditions or inhomogeneous sensitivities of each observation using three different telescopes. It is likely that the non-detection of new masers in our NLS1 sample is primarily due to insufficient sensitivities of our observations. Including the five known NLS1 masers, the total detection rate of the H2O maser in NLS1s is not remarkably different from that of type 2 Seyfert galaxies or LINERs. However, more extensive and systematic searches of NLS1 would be required for a statistical discussion of the detection rate of the NLS1 maser, compared with that of type 2 Seyferts or LINERs.

  5. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei, E-mail: gbmou@ustc.edu.cn [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei 230026 (China)

    2017-07-20

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  6. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei

    2017-01-01

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  7. Numerical Study on Outflows in Seyfert Galaxies I: Narrow Line Region Outflows in NGC 4151

    Mou, Guobin; Wang, Tinggui; Yang, Chenwei

    2017-07-01

    The origin of narrow line region (NLR) outflows remains unknown. In this paper, we explore the scenario in which these outflows are circumnuclear clouds driven by energetic accretion disk winds. We choose the well-studied nearby Seyfert galaxy NGC 4151 as an example. By performing 3D hydrodynamical simulations, we are able to reproduce the radial distributions of velocity, mass outflow rate, and kinetic luminosity of NLR outflows in the inner 100 pc deduced from spatial resolved spectroscopic observations. The demanded kinetic luminosity of disk winds is about two orders of magnitude higher than that inferred from the NLR outflows, but is close to the ultrafast outflows (UFO) detected in the X-ray spectrum and a few times lower than the bolometric luminosity of the Seyfert. Our simulations imply that the scenario is viable for NGC 4151. The existence of the underlying disk winds can be confirmed by their impacts on higher density ISM, e.g., shock excitation signs, and the pressure in NLR.

  8. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S.; Bentz, M. C.; Vestergaard, M.; Kilerci-Eser, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Dalla Bontà, E.; G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" data-affiliation=" (Dipartimento di Fisica e Astronomia G. Galilei, Università di Padova, Vicolo dell'Osservatorio 3 I-35122, Padova (Italy))" >Ciroi, S.

    2013-01-01

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n e ∼ 10 5 cm –3 ) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  9. The size of the narrow-line-emitting region in the Seyfert 1 galaxy NGC 5548 from emission-line variability

    Peterson, B. M.; Denney, K. D.; De Rosa, G.; Grier, C. J.; Pogge, R. W.; Kochanek, C. S. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, 25 Park Place, Suite 610, Atlanta, GA 30303 (United States); Vestergaard, M.; Kilerci-Eser, E. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Dalla Bontà, E.; Ciroi, S. [Dipartimento di Fisica e Astronomia " G. Galilei," Università di Padova, Vicolo dell' Osservatorio 3 I-35122, Padova (Italy)

    2013-12-20

    The narrow [O III] λλ4959, 5007 emission-line fluxes in the spectrum of the well-studied Seyfert 1 galaxy NGC 5548 are shown to vary with time. From this we show that the narrow-line-emitting region has a radius of only 1-3 pc and is denser (n {sub e} ∼ 10{sup 5} cm{sup –3}) than previously supposed. The [O III] line width is consistent with virial motions at this radius given previous determinations of the black hole mass. Since the [O III] emission-line flux is usually assumed to be constant and is therefore used to calibrate spectroscopic monitoring data, the variability has ramifications for the long-term secular variations of continuum and emission-line fluxes, though it has no effect on shorter-term reverberation studies. We present corrected optical continuum and broad Hβ emission-line light curves for the period 1988-2008.

  10. A long XMM-Newton observation of an extreme narrow-line Seyfert 1: PG 1244+026

    Jin, C.; Done, C.; Middleton, M.; Ward, M.

    2013-01-01

    We explore the origin of the strong soft X-ray excess in narrow-line Seyfert 1 galaxies using spectral-timing information from a 120 ks XMM-Newton observation of PG 1244+026. Spectral fitting alone cannot distinguish between a true additional soft X-ray continuum component and strongly

  11. Narrow Line Cooling of 88Sr Atoms in the Magneto-optical Trap for Precision Frequency Standard

    Strelkin, S. A.; Galyshev, A. A.; Berdasov, O. I.; Gribov, A. Yu.; Sutyrin, D. V.; Khabarova, K. Yu.; Kolachevsky, N. N.; Slyusarev, S. N.

    We report on our progress toward the realization of a Strontium optical lattice clock, which is under development at VNIIFTRI as a part of GLONASS program. We've prepared the narrow line width laser system for secondary cooling of 88Sr atoms which allows us to reach atom cloud temperature below 3 μK after second cooling stage.

  12. THE RADIO PROPERTIES OF RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES ON PARSEC SCALES

    Gu, Minfeng; Chen, Yongjun; Shen, Zhiqiang [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Komossa, S.; Zensus, J. A. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Yuan, Weimin [Key Lab for Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Wajima, Kiyoaki [Korea Astronomy and Space Science Institute, 776 Daedeokdae-ro, Yuseong, Daejeon 305-348 (Korea, Republic of); Zhou, Hongyan, E-mail: gumf@shao.ac.cn [Polar Research Institute of China, 451 Jinqiao Road, Shanghai 200136 (China)

    2015-11-15

    We present the detection of the compact radio structures of 14 radio-loud narrow-line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array (VLBA) observations at 5 GHz performed in 2013. While 50% of the sources of our sample show a compact core only, the remaining 50% exhibit a core-jet structure. The measured brightness temperatures of the cores range from 10{sup 8.4} to 10{sup 11.4} K with a median value of 10{sup 10.1} K, indicating that the radio emission is from non-thermal jets, and that, likely, most sources are not strongly beamed, thus implying a low jet speed in these radio-loud NLS1 galaxies. In combination with archival data taken at multiple frequencies, we find that seven sources show flat or even inverted radio spectra, while steep spectra are revealed in the remaining seven objects. Although all of these sources are very radio-loud with R > 100, their jet properties are diverse in terms of their milliarcsecond (mas) scale (parsec scale) morphology and their overall radio spectral shape. The evidence for slow jet speeds (i.e., less relativistic jets), in combination with the low kinetic/radio power, may offer an explanation for the compact VLBA radio structure in most sources. The mildly relativistic jets in these high accretion rate systems are consistent with a scenario where jets are accelerated from the hot corona above the disk by the magnetic field and the radiation force of the accretion disk. Alternatively, a low jet bulk velocity can be explained by low spin in the Blandford–Znajek mechanism.

  13. Photoionization Models of the H_2 Emission of the Narrow Line Region of AGNs

    Aleman, I.; Gruenwald, R.

    2011-05-01

    The excitation mechanism of the narrow line region (NLR) of AGNs is still an open question. Excitation by UV radiation from O and B stars, x-rays from the central black hole, shock from supernovae or jets, or a combination of these mechanisms have been suggested. In the present work, we use photoionization models to study the excitation mechanisms of the H_2 infrared emission lines in the NLR. In the literature, analyzes of the H_2 emission have been done assuming that the molecules is present only in neutral regions (photodissociation regions, x-ray-dominated regions, or shocks; Veilleux et al. 1997, Krabbe et al. 2000, Rigopoulou et al. 2002, Rodriguez-Ardila et al. 2004, 2005, and Davies et al. 2005). However, they are not conclusive. In previous work (Aleman & Gruenwald 2004, 2011), we show that the H_2 emission from the ionized region of PNe can be significant for planetary nebulae (PNe) with hot central stars (T⋆ > 150000 K). Such stars produce copious amounts of high energy photons, which create an extended partially ionized region that favors the H_2 survival. The conditions in the NLR are similar to those in PNe with hot central stars, so we can expect that the H_2 emission might also be important. We obtain and analyze a grid of photoionization models for different NRL parameters. We study the resulting H_2 density and emission, as well as, the formation, destruction, excitation, and de-excitation mechanisms. The higher values observed for the H_2 1-0 S(1)/Brγ ratio cannot be reproduced by our models. The calculated ratios are between 10^-8 and 10^-1, while the observational ration can be as high as 10. The calculated ratio is strongly anti-correlated with the ionization parameter (U) and only models with U<10-3 result in ratios inside the observational range. We show that the NLR is an environment more hostile to the H_2 molecule than the ionized region of PNe. Another interesting result of our calculations is that the H_2 formation on grain surfaces

  14. Narrow line-width Tm3+ doped double-clad silica fiber laser based on in-line cascade biconical tapers filter

    Tian, Y; Zhao, J Q; Wang, W; Wang, Y Z; Gao, W

    2010-01-01

    Narrow line-width 793 nm laser diode cladding pumped Tm 3+ doped double cladding silica fiber laser with in-line four concatenated tapers filter was reported for the first time to our knowledge. These cascade tapers located 3.6 cm from the output end of the fiber laser was fabricated by heating and stretching method. The taper's transmitted power response as a function of wavelength was described by using local mode coupling theory and successive tapers filter model. The wavelength filter function of the in-line cascade tapers in a linear cavity fiber laser was demonstrated, and the experimental result agreed with these theories. The maximum output laser power was 736 mW, corresponding to single peak of laser spectrum with narrow line-width of ∼ 60 pm

  15. Ultraviolet SO lasers optically pumped by a tunable, line-narrowed KrF laser

    Stuart, B.C.D.

    1992-06-01

    The feasibility of an ultraviolet energy storage laser based on the long-lived sulfur monoxide A 3 π-χ 3 Σ - electronic transition was investigated, and an ultraviolet laser based on the short-lived SO(B 3 Σ - -χ 3 Σ - ) transition was demonstrated and modeled. Both were optically pumped by a continuously tunable, line-narrowed KrF laser developed for efficient rotationally resolved excitation of SO. SO was produced by both microwave discharge and excimer laser photolysis of the precursor molecules SO 2 and SOCl 2 , with a maximum SO concentration (10 16 cm -3 ) generated by ArF (193 nm) photodissociation of SO 2 . Laser induced fluorescence of SO was used to study the excitation spectroscopy, vibrational branching ratios, lifetimes and deactivation rates. The radiative lifetime of SO(A 3 π 2 ,v' = 5) was measured to be 6.9 μs and that of SO(B,v' = 1) to be 33 ns. Lifetimes in the highly perturbed SO(B,v' = 2) level ranged from 28--90 ns. Measurements and modeling of the excitation saturation fluence as a function of buffer gas pressure determined what fraction of the ground state SO(X) molecules could be excited to SO(A) or SO(B). No evidence of excited state absorption was seen. Lasing on six new ultraviolet SO(B-X) vibrational bands in the range 262--315 nm was demonstrated. SO(B-X) pulse energies of up to 11 μJ were obtained and the gain coefficient was estimated to be 0.1 cm -1 . A multi-level rate equation model of the SO(B-X) excitation and lasing transitions, including collisional rotational mixing, described the dynamics of the lasing and measured output very well. Modeling showed and experiments confirmed that the maximum possible SO laser gain simply corresponded to saturating the excitation of a single rotational level. Collisional coupling of the rotational levels increased the laser output energy

  16. NARROW-LINE X-RAY-SELECTED GALAXIES IN THE CHANDRA -COSMOS FIELD. I. OPTICAL SPECTROSCOPIC CATALOG

    Pons, E.; Watson, M. G. [University of Leicester, Leicester (United Kingdom); Elvis, M.; Civano, F. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)

    2016-04-20

    The COSMOS survey is a large and deep survey with multiwavelength observations of sources from X-rays to the UV, allowing an extensive study of their properties. The central 0.9 deg{sup 2} of the COSMOS field have been observed by Chandra with a sensitivity up to 1.9 × 10{sup −16} erg cm{sup −2} s{sup −1} in the full (0.5–10 keV) band. Photometric and spectroscopic identification of the Chandra -COSMOS (C-COSMOS) sources is available from several catalogs and campaigns. Despite the fact that the C-COSMOS galaxies have a reliable spectroscopic redshift in addition to a spectroscopic classification, the emission-line properties of this sample have not yet been measured. We present here the creation of an emission-line catalog of 453 narrow-line sources from the C-COSMOS spectroscopic sample. We have performed spectral fitting for the more common lines in galaxies ([O ii] λ 3727, [Ne iii] λ 3869, H β , [O iii] λλ 4959, 5007, H α , and [N ii] λλ 6548, 6584). These data provide an optical classification for 151 (i.e., 33%) of the C-COSMOS narrow-line galaxies based on emission-line diagnostic diagrams.

  17. CORRELATION ANALYSIS OF A LARGE SAMPLE OF NARROW-LINE SEYFERT 1 GALAXIES: LINKING CENTRAL ENGINE AND HOST PROPERTIES

    Xu Dawei; Komossa, S.; Wang Jing; Yuan Weimin; Zhou Hongyan; Lu Honglin; Li Cheng; Grupe, Dirk

    2012-01-01

    We present a statistical study of a large, homogeneously analyzed sample of narrow-line Seyfert 1 (NLS1) galaxies, accompanied by a comparison sample of broad-line Seyfert 1 (BLS1) galaxies. Optical emission-line and continuum properties are subjected to correlation analyses, in order to identify the main drivers of the correlation space of active galactic nuclei (AGNs), and of NLS1 galaxies in particular. For the first time, we have established the density of the narrow-line region as a key parameter in Eigenvector 1 space, as important as the Eddington ratio L/L Edd . This is important because it links the properties of the central engine with the properties of the host galaxy, i.e., the interstellar medium (ISM). We also confirm previously found correlations involving the line width of Hβ and the strength of the Fe II and [O III] λ5007 emission lines, and we confirm the important role played by L/L Edd in driving the properties of NLS1 galaxies. A spatial correlation analysis shows that large-scale environments of the BLS1 and NLS1 galaxies of our sample are similar. If mergers are rare in our sample, accretion-driven winds, on the one hand, or bar-driven inflows, on the other hand, may account for the strong dependence of Eigenvector 1 on ISM density.

  18. The origin of narrowing of the Si 2p coincidence photoelectron spectroscopy main line of Si(1 0 0) surface

    Ohno, Masahide

    2011-01-01

    Highlights: → The Si 2p coincidence photoelectron spectroscopy (PES) main line of Si(1 0 0) is calculated. → The PES main line shows an asymmetric line shape change compared to the singles one. → The narrowing of the coincidence Si 2p PES main line is well reproduced. → The inherent mechanism of APECS is explained by a many-body theory. - Abstract: The Si 2p photoelectron spectroscopy (PES) main line of Si(1 0 0) surface measured in coincidence with the singles (noncoincidence) Si L 2,3 -VV Auger-electron spectroscopy (AES) elastic peak is calculated. The agreement with the experiment is good. The present work is the first many-body calculation of the experimental coincidence PES spectrum of solid surface. The narrowing of the coincidence Si 2p PES main line compared to the singles one is due to the mechanism inherent in the coincidence PES. The inherent mechanism is explained by a many-body theory by which photoemission and Auger-electron emission are treated on the same footing.

  19. Effects of diffusion and surface interactions on the line shape of electron paramagnetic resonances in the presence of a magnetic field gradient

    Schaden, M.; Zhao, K. F.; Wu, Z.

    2007-01-01

    In an evanescent wave magnetometer the Zeeman polarization is probed at micrometer to submicrometer distances from the cell surface. The electron paramagnetic resonance lines of an evanescent wave magnetometer in the presence of a magnetic field gradient exhibit edge enhancement seen previously in nuclear magnetic resonance lines. We present a theoretical model that describes quantitatively the shape of the magnetic resonance lines of an evanescent wave magnetometer under a wide range of experimental conditions. It accounts for diffusion broadening in the presence of a magnetic field gradient as well as interactions of spin polarized Rb atoms with the coated Pyrex glass surfaces. Depending on the field gradient, cell thickness, and buffer gas pressure, the resonance line may have the form of a single asymmetric peak or two peaks localized near the front and back surfaces in frequency space. The double-peaked response depends on average characteristics of the surface interactions. Its shape is sensitive to the dwell time, relaxation probability, and average phase shift of adsorbed spin polarized Rb atoms

  20. Narrow line width operation of a 980 nm gain guided tapered diode laser bar

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Barrientos-Barria, Jessica

    2011-01-01

    We demonstrate two different schemes for the spectral narrowing of a 12 emitter 980 nm gain guided tapered diode laser bar. In the first scheme, a reflective grating has been used in a Littman Metcalf configuration and the wavelength of the laser emission could be narrowed down from more than 5.......5 nm in the free running mode to 0.04 nm (FWHM) at an operating current of 30 A with an output power of 8 W. The spectrum was found to be tunable within a range of 16 nm. In the second scheme, a volume Bragg grating has been used to narrow the wavelength of the laser bar from over 5 nm to less than 0.......2 nm with an output of 5 W at 20 A. To our knowledge, this is the first time spectral narrowing has been performed on a gain guided tapered diode laser bar. In the Littman Metcalf configuration, the spectral brightness has been increased by 86 times and in the volume Bragg grating cavity the spectral...

  1. Narrow CIV lambda 1549A Absorption Lines in Moderate-Redshift Quasars

    Vestergaard, Marianne

    2002-01-01

    A large, high-quality spectral data base of well-selected, moderate-redshift radio-loud and radio-quiet quasars is used to characterize the incidence of narrow associated CIV lambda 1549 absorption, and how this may depend on some quasar properties, including radio-type. Preliminary results...

  2. Unshifted Metastable He I* Mini-broad Absorption Line System in the Narrow-line Type 1 Quasar SDSS J080248.18+551328.9

    Ji, Tuo; Zhou, Hongyan; Jiang, Peng; Wang, Tinggui; Ge, Jian; Wang, Huiyuan; Komossa, S.; Hamann, Fred; Zuther, Jens; Liu, Wenjuan; Lu, Honglin; Zuo, Wenwen; Yang, Chenwei; Yuan, Weimin

    2015-02-01

    We report the identification of an unusual absorption-line system in the quasar SDSS J080248.18+551328.9 and present a detailed study of the system, incorporating follow-up optical and near-IR spectroscopy. A few tens of absorption lines are detected, including He I*, Fe II*, and Ni II*, which arise from metastable or excited levels, as well as resonant lines in Mg I, Mg II, Fe II, Mn II, and Ca II. All of the isolated absorption lines show the same profile of width Δv ~ 1500 km s-1 centered at a common redshift as that of the quasar emission lines, such as [O II], [S II], and hydrogen Paschen and Balmer series. With narrow Balmer lines, strong optical Fe II multiplets, and weak [O III] doublets, its emission-line spectrum is typical for that of a narrow-line Seyfert 1 galaxy (NLS1). We have derived reliable measurements of the gas-phase column densities of the absorbing ions/levels. Photoionization modeling indicates that the absorber has a density of n H ~ (1.0-2.5) × 105 cm-3 and a column density of N H ~ (1.0-3.2) × 1021 cm-2 and is located at R ~100-250 pc from the central supermassive black hole. The location of the absorber, the symmetric profile of the absorption lines, and the coincidence of the absorption- and emission-line centroid jointly suggest that the absorption gas originates from the host galaxy and is plausibly accelerated by stellar processes, such as stellar winds and/or supernova explosions. The implications for the detection of such a peculiar absorption-line system in an NLS1 are discussed in the context of coevolution between supermassive black hole growth and host galaxy buildup.

  3. Microscopic nature of inhomogeneous line broadening: Analysis of the excitation-line-narrowing spectra of Cf4+ in CeF4

    Liu, G.K.; Huang, J.; Beitz, J.V.

    1993-01-01

    Optical transitions between 5f states of tetravalent californium ion doped (1 metal-atom %) into CeF 4 exhibit unusually large inhomogeneous broadening. The nature of the inhomogeneous broadening in this system has been studied by using fluorescence line narrowing and excitation line narrowing (ELN). It is shown that the energy distributions of different electronic states of Cf 4+ in this system are correlated. In the ELN experiments, reduced excitation linewidth was obtained when selectively monitoring fluorescence emission. A linear relation was observed between the excitation energies of crystal-field states of the 5 G 4' manifold and the fluorescence wavelength monitored across the inhomogeneous profile of a 5 G 6' -- 7 F 6' transition. Analysis of these results by means of a microscopic theory proposed by Laird and Skinner [J. Chem. Phys. 90, 3880 (1989)] has provided insights into the structural properties of this disordered system

  4. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    Pascucci, I.; Simon, M. N. [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Edwards, S. [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States); Heyer, M. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); Rigliaco, E. [Institute for Astronomy, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zurich (Switzerland); Hillenbrand, L. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Gorti, U.; Hollenbach, D., E-mail: pascucci@lpl.arizona.edu [SETI Institute, Mountain View, CA 94043 (United States)

    2015-11-20

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions.

  5. NARROW Na AND K ABSORPTION LINES TOWARD T TAURI STARS: TRACING THE ATOMIC ENVELOPE OF MOLECULAR CLOUDS

    Pascucci, I.; Simon, M. N.; Edwards, S.; Heyer, M.; Rigliaco, E.; Hillenbrand, L.; Gorti, U.; Hollenbach, D.

    2015-01-01

    We present a detailed analysis of narrow Na i and K i absorption resonance lines toward nearly 40 T Tauri stars in Taurus with the goal of clarifying their origin. The Na i λ5889.95 line is detected toward all but one source, while the weaker K i λ7698.96 line is detected in about two-thirds of the sample. The similarity in their peak centroids and the significant positive correlation between their equivalent widths demonstrate that these transitions trace the same atomic gas. The absorption lines are present toward both disk and diskless young stellar objects, which excludes cold gas within the circumstellar disk as the absorbing material. A comparison of Na i and CO detections and peak centroids demonstrates that the atomic gas and molecular gas are not co-located, the atomic gas being more extended than the molecular gas. The width of the atomic lines corroborates this finding and points to atomic gas about an order of magnitude warmer than the molecular gas. The distribution of Na i radial velocities shows a clear spatial gradient along the length of the Taurus molecular cloud filaments. This suggests that absorption is associated with the Taurus molecular cloud. Assuming that the gradient is due to cloud rotation, the rotation of the atomic gas is consistent with differential galactic rotation, whereas the rotation of the molecular gas, although with the same rotation axis, is retrograde. Our analysis shows that narrow Na i and K i absorption resonance lines are useful tracers of the atomic envelope of molecular clouds. In line with recent findings from giant molecular clouds, our results demonstrate that the velocity fields of the atomic and molecular gas are misaligned. The angular momentum of a molecular cloud is not simply inherited from the rotating Galactic disk from which it formed but may be redistributed by cloud–cloud interactions

  6. RADIO-LOUD NARROW-LINE SEYFERT 1 AS A NEW CLASS OF GAMMA-RAY ACTIVE GALACTIC NUCLEI

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Cameron, R. A.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Brigida, M.; Bruel, P.; Burnett, T. H.; Caliandro, G. A.

    2009-01-01

    We report the discovery with Fermi/LAT of γ-ray emission from three radio-loud narrow-line Seyfert 1 galaxies: PKS 1502+036 (z = 0.409), 1H 0323+342 (z = 0.061), and PKS 2004 - 447 (z = 0.24). In addition to PMN J0948+0022 (z = 0.585), the first source of this type to be detected in γ rays, they may form an emerging new class of γ-ray active galactic nuclei (AGNs). These findings can have strong implications on our knowledge about relativistic jets and the unified model of the AGN.

  7. VizieR Online Data Catalog: QSOs narrow absorption line variability (Hacker+, 2013)

    Hacker, T. L.; Brunner, R. J.; Lundgren, B. F.; York, D. G.

    2013-06-01

    Catalogues of 2,522 QAL systems and 33 variable NAL systems detected in SDSS DR7 quasars with repeat observations. The object identifiers, position coordinates, and plate-MJD-fibre designations are taken from the SpecObjAll table in the SDSS Catalogue Archive Server (CAS) while the quasar redshifts (zqso) are from Hewett & Wild (2010, Cat. J/MNRAS/405/2302). The absorption system redshift (zabs), system grade, and detected lines are outputs of the York et al. (2013, in. prep.) QAL detection pipeline. Some absorption lines are flagged based on alternate identifications (a), proximity of masked pixels (b), or questionable continuum fits (c). (3 data files).

  8. A Revised Broad-line Region Radius and Black Hole Mass for the Narrow-line Seyfert 1 NGC 4051

    Denney, K. D.; Watson, L. C.; Peterson, B. M.

    2009-01-01

    ) radius and the optical continuum luminosity—the R BLR-L relationship. Our new measurements of the lag time between variations in the continuum and Hß emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87+0.54 -0.50 light days and black hole mass of M...

  9. Two active states of the narrow-line gamma-ray-loud AGN GB 1310+487

    Sokolovsky, K. V.

    2014-01-01

    Context. Previously unremarkable, the extragalactic radio source GB1310+487 showed a γ-ray flare on 2009 November 18, reaching a daily flux of ~ 10"-"6 photons cm"-"2 s"-"1 at energies E > 100MeV and became one of the brightest GeV sources for about two weeks. Its optical spectrum shows strong forbidden-line emission while lacking broad permitted lines, which is not typical for a blazar. Instead, the spectrum resembles those of narrow emission-line galaxies. Aims. We investigate changes in the object’s radio-to-GeV spectral energy distribution (SED) during and after the prominent γ-ray flare with the aim of determining the nature of the object and of constraining the origin of the variable high-energy emission. Methods. The data collected by the Fermi and AGILE satellites at γ-ray energies; Swift at X-ray and ultraviolet (UV); the Kanata, NOT, and Keck telescopes at optical; OAGH andWISE at infrared (IR); and IRAM30m, OVRO 40m, Effelsberg 100m, RATAN-600, and VLBA at radio are analyzed together to trace the SED evolution on timescales of months. Results. The γ-ray/radio-loud narrow-line active galactic nucleus (AGN) is located at redshift z = 0.638. It shines through an unrelated foreground galaxy at z = 0.500. The AGN light is probably amplified by gravitational lensing. The AGN SED shows a two-humped structure typical of blazars and γ-ray-loud narrow-line Seyfert 1 galaxies, with the high-energy (inverse-Compton) emission dominating by more than an order of magnitude over the low-energy (synchrotron) emission during γ-ray flares. The difference between the two SED humps is smaller during the low-activity state. Fermi observations reveal a strong correlation between the γ-ray flux and spectral index, with the hardest spectrum observed during the brightest γ-ray state. The γ-ray flares occurred before and during a slow rising trend in the radio, but no direct association between γ-ray and radio flares could be established. Conclusions. If the

  10. An XMM-Newton Study of the Bright Ultrasoft Narrow-Line Quasar NAB 0205+024

    Brandt, Niel

    2004-01-01

    The broad-band X-ray continuum of NAB 0205424 is well constrained due to the excellent photon statistics obtained (about 97,700 counts), and its impressive soft X-ray excess is clearly apparent. The hard X-ray power law has become notably steeper than when NAB 0205424 was observed with ASCA, attesting to the presence of significant X-ray spectral variability. A strong and broad emission feature is detected from about 5 to 6.4 keV, and we have modeled this as a relativistic line emitted close to the black hole from a narrow annulus of the accretion disk. Furthermore, a strong X-ray flare is detected with a hard X-ray spectrum; this flare may be responsible for illuminating the inner line-emitting part of the accretion disk. The combined observational results can be broadly interpreted in terms of the "thundercloud model proposed by Merloni & Fabian (2001).

  11. The Extended Narrow-line Region of Two Type-I Quasi-stellar Objects

    Oh, S.; Woo, J.-H.; Bennert, V.N.; Jungwiert, Bruno; Haas, M.; Leipski, C.; Albrecht, M.

    2013-01-01

    Roč. 767, č. 2 (2013), 117/1-117/7 ISSN 0004-637X Institutional support: RVO:67985815 Keywords : active galaxies * quasars * emission lines Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.280, year: 2013

  12. Multiwavelength Monitoring of the Enigmatic Narrow-Line Seyfert 1 PMN J0948 0022 in March-July 2009

    Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Axelsson, M.; /Stockholm U. /Stockholm U., OKC; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R. /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E. /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, T.H.; /Washington U., Seattle; Caliandro, G.A.; /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /Milan Polytechnic /DAPNIA, Saclay /ASDC, Frascati /INFN, Perugia /Perugia U. /NASA, Goddard /NASA, Goddard /CSST, Baltimore /SISSA, Trieste /Naval Research Lab, Wash., D.C. /George Mason U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Garching, Max Planck Inst., MPE /Stockholm U. /Stockholm U., OKC /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /ASDC, Frascati /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Ecole Polytechnique /Brera Observ. /INFN, Trieste /Bonn, Max Planck Inst., Radioastron. /Hiroshima U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; /more authors..

    2012-03-29

    Following the recent discovery of {gamma} rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to {gamma} rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to {gamma}-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the {gamma}-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars.

  13. MULTIWAVELENGTH MONITORING OF THE ENIGMATIC NARROW-LINE SEYFERT 1 PMN J0948+0022 IN 2009 MARCH-JULY

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Bloom, E. D.; Borgland, A. W.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bonamente, E.; Brigida, M.; Bruel, P.; Burnett, T. H.

    2009-01-01

    Following the recent discovery of γ rays from the radio-loud narrow-line Seyfert 1 galaxy PMN J0948+0022 (z = 0.5846), we started a multiwavelength campaign from radio to γ rays, which was carried out between the end of 2009 March and the beginning of July. The source displayed activity at all the observed wavelengths: a general decreasing trend from optical to γ-ray frequencies was followed by an increase of radio emission after less than two months from the peak of the γ-ray emission. The largest flux change, about a factor of about 4, occurred in the X-ray band. The smallest was at ultraviolet and near-infrared frequencies, where the rate of the detected photons dropped by a factor 1.6-1.9. At optical wavelengths, where the sampling rate was the highest, it was possible to observe day scale variability, with flux variations up to a factor of about 3. The behavior of PMN J0948+0022 observed in this campaign and the calculated power carried out by its jet in the form of protons, electrons, radiation, and magnetic field are quite similar to that of blazars, specifically of flat-spectrum radio quasars. These results confirm the idea that radio-loud narrow-line Seyfert 1 galaxies host relativistic jets with power similar to that of average blazars.

  14. Phosphorus-31 MRI of bones using quadratic echo line-narrowing

    Frey, Merideth; Barrett, Sean; Insogna, Karl; Vanhouten, Joshua

    2012-02-01

    There is a great need to probe the internal composition of bone on the sub-0.1 mm length scale, both to study normal features and to look for signs of disease. Despite the obvious importance of the mineral fraction to the biomechanical properties of skeletal tissue, few non-destructive techniques are available to evaluate changes in its chemical structure and functional microarchitecture on the interior of bones. MRI would be an excellent candidate, but bone is a particularly challenging tissue to study given the relatively low water density and wider linewidths of its solid components. Recent fundamental research in quantum computing gave rise to a new NMR pulse sequence - the quadratic echo - that can be used to narrow the broad NMR spectrum of solids. This offers a new route to do high spatial resolution, 3D ^31P MRI of bone that complements conventional MRI and x-ray based techniques to study bone physiology and structure. We have used our pulse sequence to do 3D ^31P MRI of ex vivo bones with a spatial resolution of (sub-450 μm)^3, limited only by the specifications of a conventional 4 Tesla liquid-state MRI system. We will describe our plans to push this technique towards the factor of 1000 increase in spatial resolution imposed by fundamental limits.

  15. A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C.; Denney, K. D.; Bentz, M. C.; Sergeev, S. G.; Borman, G. A.; Kaspi, S.; Bord, D. J.; Che, X.; Chen, C.; Cohen, S. A.

    2012-01-01

    We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II λ4686 broad emission line relative to the optical continuum to be 2.7 ± 0.6 days and the lag in the Hβλ4861 broad emission line to be 13.9 ± 0.9 days. Combined with the line width, the He II lag yields a black hole mass M BH = (2.6 ± 0.8) × 10 7 M ☉ . This measurement is consistent with measurements made using the Hβλ4861 line, suggesting that the He II emission originates in the same structure as Hβ, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

  16. A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

    Grier, C. J.; Peterson, B. M.; Pogge, R. W.; Martini, Paul; Zu, Y.; Kochanek, C. S.; Shappee, B. J.; Stanek, K. Z.; Araya Salvo, C.; Beatty, T. G.; Bird, J. C. [Department of Astronomy, The Ohio State University, 140 W 18th Avenue, Columbus, OH 43210 (United States); Denney, K. D. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Bentz, M. C. [Department of Physics and Astronomy, Georgia State University, Astronomy Offices, One Park Place South SE, Suite 700, Atlanta, GA 30303 (United States); Sergeev, S. G.; Borman, G. A. [Crimean Astrophysical Observatory, P/O Nauchny Crimea 98409 (Ukraine); Kaspi, S. [School of Physics and Astronomy, Raymond and Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel); Bord, D. J. [Department of Natural Sciences, The University of Michigan-Dearborn, 4901 Evergreen Rd, Dearborn, MI 48128 (United States); Che, X. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 41809 (United States); Chen, C.; Cohen, S. A. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); and others

    2012-01-15

    We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

  17. A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051

    Denney, K. D.; Watson, L. C.; Peterson, B. M.

    2009-01-01

    We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved Hβ reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ∼2-3σ outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity-the R BLR -L relationship. Our new measurements of the lag time between variations in the continuum and Hβ emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of R BLR = 1.87 +0.54 -0.50 light days and black hole mass of M BH = (1.73 +0.55 -0.52 ) x 10 6 M sun . This radius is consistent with that expected from the R BLR -L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved Hβ light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

  18. Internal Displacement Reactions in Multicomponent Oxides: Part I. Line Compounds with Narrow Homogeneity Range

    Reddy, SNS; Leonard, DN; Wiggins, LB; Jacob, KT

    2005-01-01

    As a model of an internal displacement reaction involving a ternary oxide line compound, the following reaction was studied at 1273 K as a function of time, t: $Fe+NiTiO_3 = Ni + FeTiO_3$ Both polycrystalline and single-crystal materials were used as the starting $NiTiO_3$ oxide. During the reaction, the Ni in the oxide compound is displaced by Fe and it precipitates as a \\gamma -(Ni-Fe) alloy. The reaction preserves the starting ilmenite structure. The product oxide has a consta...

  19. Spectral properties of the narrow-line region in Seyfert galaxies selected from the SDSS-DR7

    Vaona, L.; Ciroi, S.; Di Mille, F.; Cracco, V.; La Mura, G.; Rafanelli, P.

    2012-12-01

    Although the properties of the narrow-line region (NLR) of active galactic nuclei (AGN) have been deeply studied by many authors in the past three decades, many questions are still open. The main goal of this work is to explore the NLR of Seyfert galaxies by collecting a large statistical spectroscopic sample of Seyfert 2 and Intermediate-type Seyfert galaxies having a high signal-to-noise ratio in order to take advantage of a high number of emission lines to be accurately measured. 2153 Seyfert 2 and 521 Intermediate-type Seyfert spectra were selected from Sloan Digital Sky Survey Data Release 7 (SDSS-DR7) with a diagnostic diagram based on the oxygen emission-line ratios. All the emission lines, broad components included, were measured by means of a self-developed code, after the subtraction of the stellar component. Physical parameters, such as internal reddening, ionization parameter, temperature, density, gas and stellar velocity dispersion were determined for each object. Furthermore, we estimated mass and radius of the NLR, kinetic energy of the ionized gas and black hole accretion rate. From the emission-line analysis and the estimated physical properties, it appears that the NLR is similar in Seyfert 2 and Intermediate-Seyfert galaxies. The only differences, lower extinction, gas kinematics in general not dominated by the host galaxy gravitational potential and higher percentage of [O III]λ5007 blue asymmetries in Intermediate-Seyfert, can be ascribed to an effect of inclination of our line of sight with respect to the torus axis.

  20. A statistical study of H i gas in nearby narrow-line AGN-hosting galaxies

    Zhu, Yi-Nan; Wu, Hong

    2015-01-01

    As a quenching mechanism, active galactic nucleus (AGN) feedback could suppress on going star formation in host galaxies. On the basis of a sample of galaxies selected from the Arecibo Legacy Fast ALFA (ALFALFA) H i survey, the dependence of the H i mass (M H i ), stellar mass (M * ), and H i-to-stellar mass ratio (M H i /M * ) on various tracers of AGN activity are presented and analyzed in this paper. Almost all the AGN hostings in this sample are gas-rich galaxies, and there is not any evidence to indicate that the AGN activity could increase or decrease either M H i or M H i /M * . The position of the cold neutral gas cannot be fixed accurately based only on available H i data, due to the large beam size of ALFALFA survey. In addition, even though AGN hostings are more easily detected by an H i survey compared with absorption line galaxies, these two types of galaxies show similar star formation history. If an AGN hosting would ultimately evolve into an old red galaxy with low cold gas, then when and how the gas has been exhausted must be solved by future hypotheses and observations.

  1. A statistical study of H i gas in nearby narrow-line AGN-hosting galaxies

    Zhu, Yi-Nan; Wu, Hong, E-mail: zyn@bao.ac.cn, E-mail: hwu@bao.ac.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2015-01-01

    As a quenching mechanism, active galactic nucleus (AGN) feedback could suppress on going star formation in host galaxies. On the basis of a sample of galaxies selected from the Arecibo Legacy Fast ALFA (ALFALFA) H i survey, the dependence of the H i mass (M{sub H} {sub i}), stellar mass (M{sub *}), and H i-to-stellar mass ratio (M{sub H} {sub i}/M{sub *}) on various tracers of AGN activity are presented and analyzed in this paper. Almost all the AGN hostings in this sample are gas-rich galaxies, and there is not any evidence to indicate that the AGN activity could increase or decrease either M{sub H} {sub i} or M{sub H} {sub i}/M{sub *}. The position of the cold neutral gas cannot be fixed accurately based only on available H i data, due to the large beam size of ALFALFA survey. In addition, even though AGN hostings are more easily detected by an H i survey compared with absorption line galaxies, these two types of galaxies show similar star formation history. If an AGN hosting would ultimately evolve into an old red galaxy with low cold gas, then when and how the gas has been exhausted must be solved by future hypotheses and observations.

  2. Narrow row and crossed lines associated with different plant densities of soybean

    Alvadi Antonio Balbinot Junior

    2015-10-01

    Full Text Available The spatial arrangement of soybean plants affects the intraspecific competition for light, water and nutrients, which can change the biomass production, incidence of pests, diseases and weeds, plant lodging, and grain yield. This work aimed to evaluate the agronomic performance under different row spacing, plant densities and crossed rows. Two field experiments were carried out in Campo Mourão, Paraná State, Southern Brazil, using the randomized complete block experimental design, in a 3x3x2 factorial arrangement, with four replications. The treatments were formed by the combination of three row spacings (0.30, 0.45, and 0.60 m, three plant densities (300,000; 450,000; and 600,000 plants ha-1, and two row design (crossed or parallel rows. For all variables, interaction of the experimental factors was not significant. The row spacing of 0.45 m provided the highest grain yield in relation to 0.30 and 0.60 m. The density of 300,000 plants ha-1 showed higher yield of soybeans in late sowing. The crossed lines did not increase the productive performance in soybean.

  3. VizieR Online Data Catalog: Quasars narrow absorption lines from SDSS (Chen+, 2015)

    Chen, Z.-F.; Gu, Q.-S.; Chen, Y.-M.; Cao, Y.

    2017-11-01

    The Baryon Oscillation Spectroscopic Survey (BOSS: Eisenstein et al. 2011AJ....142...72E; Paris et al. 2012, Cat. VII/269) is the main dark-time legacy survey of the third stage of the SDSS, which used the same 2.5-m telescope (Gunn et al. 2006AJ....131.2332G; Ross et al. 2012, J/ApJS/199/3) as the first and second stages of the SDSS (hereafter SDSS-I/II). SDSS-I/II spectra have a wavelength coverage from 3800-9200Å with a spectral resolution of 1800-2200 (e.g. York et al. 2000AJ....120.1579Y). BOSS spectra span a range from 3600-10500Å at a resolution of 1300-2500 (Paris et al. 2012, Cat. VII/269). During the first two years, BOSS detected 87822 quasars over an area of 3275 deg2, including 7932 quasars that were observed by SDSS-I/II as well. Quasars observed by both SDSS-I/II and BOSS provide a remarkable chance to study the variabilities of absorption lines in a large population. Throughout this work, we take the quasar emission redshifts provided by Hewett & Wild (2010, J/MNRAS/405/2302, http://das.sdss.org/va/HewettWilddr7qso_newz/) directly. (2 data files).

  4. Intra-night optical variability properties of X-ray bright Narrow-line Seyfert 1 galaxies

    Ojha, Vineet; Chand, Hum; Gopal-Krishna

    2018-04-01

    We present Intra Night Optical Variability (INOV) study of the 9 Narrow-line Seyfert 1 (NLSy 1) galaxies which are detected in X-ray at more than 3σ level. Our observations cover a total of 9 nights ( 36 hr) with each NLSy 1 monitored for ≥ 3.5 hr in each night. After applying F-test to assess variability status of these sources, we found none of these sources to be variable. Such non-variability nature of X-ray detected NLSy 1 galaxies suggests the lack of jet dominance as far as X-ray emission is concerned. Higher photometric accuracy for these faint sources, achievable with the newly installed ARIES 3.6m DOT will be helpful.

  5. Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies

    Lähteenmäki, A.; Järvelä, E.; Ramakrishnan, V.; Tornikoski, M.; Tammi, J.; Vera, R. J. C.; Chamani, W.

    2018-06-01

    We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections. 37 GHz data are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/L1

  6. Outflows in the narrow-line region of bright Seyfert galaxies - I. GMOS-IFU data

    Freitas, I. C.; Riffel, R. A.; Storchi-Bergmann, T.; Elvis, M.; Robinson, A.; Crenshaw, D. M.; Nagar, N. M.; Lena, D.; Schmitt, H. R.; Kraemer, S. B.

    2018-05-01

    We present two-dimensional maps of emission-line fluxes and kinematics, as well as of the stellar kinematics of the central few kpc of five bright nearby Seyfert galaxies - Mrk 6, Mrk 79, Mrk 348, Mrk 607, and Mrk 1058 - obtained from observations with the Gemini Multi-Object Spectrograph Integral Field Unit on the Gemini North Telescope. The data cover the inner 3.5 arcsec × 5.0 arcsec - corresponding to physical scales in the range 0.6 × 0.9-1.5 × 2.2 kpc2 - at a spatial resolution ranging from 110 to 280 pc with a spectral coverage of 4300-7100 Å and velocity resolution of ≈90 km s-1. The gas excitation is Seyfert like everywhere but show excitation gradients that are correlated with the gas kinematics, reddening and/or the gas density. The gas kinematics show in all cases two components: a rotation one similar to that observed in the stellar velocity field, and an outflow component. In the case of Mrk607, the gas is counter-rotating relative to the stars. Enhanced gas velocity dispersion is observed in association with the outflows according to two patterns: at the locations of the highest outflow velocities along the ionization axis or perpendicularly to it in a strip centred at the nucleus that we attribute to an equatorial outflow. Bipolar outflows are observed in Mrk 348 and Mrk 79, while in Mrk 1058 only the blueshifted part is clearly observed, while in cases of Mrk 6 and Mrk 607, the geometry of the outflow needs further constraints from modelling to be presented in a forthcoming study, where the mass flow rate and powers will also be obtained.

  7. Electron paramagnetic resonance

    Al'tshuler, S A

    2013-01-01

    Electron Paramagnetic Resonance is a comprehensive text on the field of electron paramagnetic resonance, covering both the theoretical background and the results of experiment. This book is composed of eight chapters that cover theoretical materials and experimental data on ionic crystals, since these are the materials that have been most extensively studied by the methods of paramagnetic resonance. The opening chapters provide an introduction to the basic principles of electron paramagnetic resonance and the methods of its measurement. The next chapters are devoted to the theory of spectra an

  8. Large-Scale Environment Properties of Narrow-Line Seyfert 1 Galaxies at z < 0.4

    Järvelä, Emilia [Metsähovi Radio Observatory, Aalto University, Espoo (Finland); Department of Electronics and Nanoengineering, Aalto University, Espoo (Finland); Lähteenmäki, A. [Metsähovi Radio Observatory, Aalto University, Espoo (Finland); Department of Electronics and Nanoengineering, Aalto University, Espoo (Finland); Tartu Observatory, Tõravere (Estonia); Lietzen, H., E-mail: emilia.jarvela@aalto.fi [Tartu Observatory, Tõravere (Estonia)

    2017-11-30

    The large-scale environment is believed to affect the evolution and intrinsic properties of galaxies. It offers a new perspective on narrow-line Seyfert 1 galaxies (NLS1) which have not been extensively studied in this context before. We study a large and diverse sample of 960 NLS1 galaxies using a luminosity-density field constructed using Sloan Digital Sky Survey. We investigate how the large-scale environment is connected to the properties of NLS1 galaxies, especially their radio loudness. Furthermore, we compare the large-scale environment properties of NLS1 galaxies with other active galactic nuclei (AGN) classes, for example, other jetted AGN and broad-line Seyfert 1 (BLS1) galaxies, to shed light on their possible relations. In general NLS1 galaxies reside in less dense large-scale environments than any of our comparison samples, thus supporting their young age. The average luminosity-density and distribution to different luminosity-density regions of NLS1 sources is significantly different compared to BLS1 galaxies. This contradicts the simple orientation-based unification of NLS1 and BLS1 galaxies, and weakens the hypothesis that BLS1 galaxies are the parent population of NLS1 galaxies. The large-scale environment density also has an impact on the intrinsic properties of NLS1 galaxies; the radio loudness increases with the increasing luminosity-density. However, our results suggest that the NLS1 population is indeed heterogeneous, and that a considerable fraction of them are misclassified. We support a suggested description that the traditional classification based on the radio loudness should be replaced with the division to jetted and non-jetted sources.

  9. NEAR-INFRARED SPECTROSCOPY OF NEARBY SEYFERT GALAXIES: IS THERE EVIDENCE FOR SHOCK EXCITATION IN NARROW-LINE REGIONS?

    Terao, K. [Graduate School of Science and Engineering, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Nagao, T.; Toba, Y. [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577 (Japan); Hashimoto, T. [National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan (China); Yanagisawa, K. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Honjo 3037-5, Kamogata-cho, Asaguchi, Okayama 719-0232 (Japan); Matsuoka, K. [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Ikeda, H. [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo, 181-8588 (Japan); Taniguchi, Y., E-mail: terao@cosmos.phys.sci.ehime-u.ac.jp [The Open University of Japan, Wakaba 2-11, Mihama-ku, Chiba 261-8586 (Japan)

    2016-12-20

    One of the important unsettled problems regarding active galactic nuclei (AGNs) is the major ionization mechanism of gas clouds in AGN narrow-line regions (NLRs). In order to investigate this issue, we present our J -band spectroscopic observations of a sample of 26 nearby Seyfert galaxies. In our study, we use the flux ratio of the following two forbidden emission lines, [Fe ii]1.257  μ m and [P ii]1.188  μ m, because it is known that this ratio is sensitive to the ionization mechanism. We obtain the [Fe ii]/[P ii] flux ratio or its lower limit for 19 objects. In addition to our data, we compile this flux ratio (or its lower limit) for 23 nearby Seyfert galaxies from the literature. Based on the collected data, we find that three Seyfert galaxies show very large lower limits of the [Fe ii]/[P ii] flux ratios (≳10): NGC 2782, NGC 5005, and Mrk 463. It is thus suggested that the contribution of the fast shock in the gas excitation is significantly large for them. However, more than half of the Seyfert galaxies in our sample show moderate [Fe ii]/[P ii] flux ratios (∼2), which is consistent with pure photoionization by power-law ionizing continuum emission. We also find that the [Fe ii]/[P ii] flux ratio shows no clear correlation with the radio loudness, suggesting that the radio jet is not the primary origin of shocks in NLRs of Seyfert galaxies.

  10. SDSS J211852.96-073227.5: a new γ-ray flaring narrow-line Seyfert 1 galaxy

    Yang, Hui; Yuan, Weimin; Yao, Su; Li, Ye; Zhang, Jin; Zhou, Hongyan; Komossa, S.; Liu, He-Yang; Jin, Chichuan

    2018-04-01

    We report on the identification of a new γ-ray-emitting narrow-line Seyfert 1 (NLS1) galaxy, SDSS J211852.96-073227.5 (hereafter J2118-0732). The galaxy, at a redshift of 0.26, is associated with a radio source of flat/inverted spectrum at high radio frequencies. The analysis of its optical spectrum obtained in the Sloan Digital Sky Survey revealed a small linewidth of the broad component of the Hβ line (FWHM = 1585 km s-1), making it a radio-loud NLS1 galaxy - an intriguing class of active galactic nuclei with exceptional multi-wavelength properties. A new γ-ray source centred at J2118-0732 was sporadically detected during 2009-2013 in form of flares by the Fermi-LAT. Our XMM-Newton observations revealed a flat X-ray spectrum described by a simple power law, and a flux variation by a factor of ˜2.5 in 5 months. The source also shows intraday variability in the infrared band. Its broad-band spectral energy distribution can be modelled by emission from a simple one-zone leptonic jet model, and the flux drop from infrared to X-rays in five months can be explained by changes of the jet parameters, though the exact values may be subject to relatively large uncertainties. With the NLS1-blazar composite nucleus, the clear detection of the host galaxy and the synchronous variations in the multi-wavelength fluxes, J2118-0732 provides a new perspective on the formation and evolution of relativistic jets under the regime of relatively small black hole masses and high accretion rates.

  11. OFDM techniques for narrow-band power line communications; OFDM-Verfahren fuer die schmalbandige Datenuebertragung im elektrischen Energieversorgungsnetz

    Hoch, Martin

    2012-07-01

    In Power Line Communications (PLC) the power distribution grid is modelled by a frequency-selective time-variant channel. Therefore, OFDM techniques are suited very well for this application since they equalize the frequency-selective behaviour in a simple fashion. For narrow-band PLC, where only little amounts of data are to be transmitted, it is advantageous to employ a non-coherent system that does not need a training sequence for channel estimation. Such type of system can be brought up with CyclicPrefix OFDM in combination with Differential Phase-Shift Keying (DPSK). In an alternative, Unique-Word OFDM, the guard interval is not filled by a cyclic prefix, but a ''unique word'', which can be deployed for channel estimation. However, there is a loss in signal-to-noise power ratio due to the special type of signal generation. This loss can be more than regained in principle, but only by applying expensive detection. Another interesting technique is Wavelet-OFDM as its transmit spectrum can be formed outstandingly because of extended transmit pulses. This implies a large overhead when short packets of data are transmitted - additionally to a training sequence, for non-coherent detection is not possible. Cyclic-Prefix OFDM and DPSK are the basis of the Physical Layers of the PLC systems ''PLC G3'' and ''PRIME''. Comparing their specifications and analyzing simulation results ''PLC G3'' turns out to be the more reliable system. In order to equalize the time-variant behaviour of the power line channel, linear equalization and Multiple Symbol Differential Detection is studied as well as algorithms to estimate the time-variant envelope. (orig.)

  12. A SAMPLE OF SEYFERT-2 GALAXIES WITH ULTRALUMINOUS GALAXY-WIDE NARROW-LINE REGIONS: QUASAR LIGHT ECHOES?

    Schirmer, M.; Diaz, R.; Levenson, N. A.; Winge, C.; Holhjem, K.

    2013-01-01

    We report the discovery of Seyfert-2 galaxies in SDSS-DR8 with galaxy-wide, ultraluminous narrow-line regions (NLRs) at redshifts z = 0.2-0.6. With a space density of 4.4 Gpc –3 at z ∼ 0.3, these 'green beans' (GBs) are amongst the rarest objects in the universe. We are witnessing an exceptional and/or short-lived phenomenon in the life cycle of active galactic nuclei (AGNs). The main focus of this paper is on a detailed analysis of the GB prototype galaxy J2240–0927 (z = 0.326). Its NLR extends over 26 × 44 kpc and is surrounded by an extended NLR. With a total [O III] λ5008 luminosity of (5.7 ± 0.9) × 10 43 erg s –1 , this is one of the most luminous NLRs known around any type-2 galaxy. Using VLT/XSHOOTER, we show that the NLR is powered by an AGN, and we derive resolved extinction, density, and ionization maps. Gas kinematics is disturbed on a global scale, and high-velocity outflows are absent or faint. This NLR is unlike any other NLR or extended emission line region known. Spectroscopy with Gemini/GMOS reveals extended, high-luminosity [O III] emission also in other GBs. WISE 24 μm luminosities are 5-50 times lower than predicted by the [O III] fluxes, suggesting that the NLRs reflect earlier, very active quasar states that have strongly subsided in less than a galaxy's light-crossing time. These light echoes, or ionization echoes, are about 100 times more luminous than any other such echo known to date. X-ray data are needed for photoionization modeling and to verify the light echoes.

  13. BAT AGN Spectroscopic Survey - III. An Observed Link Between AGN Eddington Ratio and Narrow-Emission-Line Ratios

    Oh, Kyuseok; Schawinski, Kevin; Koss, Michael; Trakhtenbrot, Benny; Lamperti, Isabella; Ricci, Claudio; Mushotzky, Richard; Veilleux, Sylvain; Berney, Simon; Crenshaw, D. Michael; hide

    2016-01-01

    We investigate the observed relationship between black hole mass (M(sub BH)), bolometric luminosity (L(sub bol)) and Eddington ratio (lambda(sub Edd)) with optical emission-line ratios ([N II] lambda6583/Halpha, [S II]lambda-lamda6716, 6731/Halpha, [O I] lamda6300/Halpha, [O III] lamda5007/Hbeta, [Ne III] lamda3869/Hbeta and He II lamda4686/Hbeta) of hard X-ray-selected active galactic nuclei (AGN) from the BAT AGN Spectroscopic Survey. We show that the [N II] lamda6583/Halpha ratio exhibits a significant correlation with lamda(sub Edd) (R(sub Pear) = -0.44, p-value 3 x 10(exp. -13) sigma = 0.28 dex), and the correlation is not solely driven by M(sub BH) or L(sub bol). The observed correlation between [N II] lamda6583/Halpha ratio and M(sub BH) is stronger than the correlation with L(sub bol), but both are weaker than the lamda(sub Edd) correlation. This implies that the large-scale narrow lines of AGN host galaxies carry information about the accretion state of the AGN central engine. We propose that [N II] lamda6583/Halpha is a useful indicator of Eddington ratio with 0.6 dex of rms scatter, and that it can be used to measure lambda(sub Edd) and thus M(sub BH) from the measured L(sub bol), even for high-redshift obscured AGN. We briefly discuss possible physical mechanisms behind this correlation, such as the mass-metallicity relation, X-ray heating, and radiatively driven outflows.

  14. Interrogating Seyferts with NebulaBayes: Spatially Probing the Narrow-line Region Radiation Fields and Chemical Abundances

    Thomas, Adam D.; Dopita, Michael A.; Kewley, Lisa J.; Groves, Brent A.; Sutherland, Ralph S.; Hopkins, Andrew M.; Blanc, Guillermo A.

    2018-04-01

    NebulaBayes is a new Bayesian code that implements a general method of comparing observed emission-line fluxes to photoionization model grids. The code enables us to extract robust, spatially resolved measurements of abundances in the extended narrow-line regions (ENLRs) produced by Active Galactic Nuclei (AGN). We observe near-constant ionization parameters but steeply radially declining pressures, which together imply that radiation pressure regulates the ENLR density structure on large scales. Our sample includes four “pure Seyfert” galaxies from the S7 survey that have extensive ENLRs. NGC 2992 shows steep metallicity gradients from the nucleus into the ionization cones. An inverse metallicity gradient is observed in ESO 138-G01, which we attribute to a recent gas inflow or minor merger. A uniformly high metallicity and hard ionizing continuum are inferred across the ENLR of Mrk 573. Our analysis of IC 5063 is likely affected by contamination from shock excitation, which appears to soften the inferred ionizing spectrum. The peak of the ionizing continuum E peak is determined by the nuclear spectrum and the absorbing column between the nucleus and the ionized nebula. We cannot separate variation in this intrinsic E peak from the effects of shock or H II region contamination, but E peak measurements nevertheless give insights into ENLR excitation. We demonstrate the general applicability of NebulaBayes by analyzing a nuclear spectrum from the non-active galaxy NGC 4691 using a H II region grid. The NLR and H II region model grids are provided with NebulaBayes for use by the astronomical community.

  15. The extreme behavior of the radio-loud narrow-line Seyfert 1 galaxy J0849+5108

    Maune, Jeremy D.; Eggen, Joseph R.; Miller, H. Richard [Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303-3083 (United States); Marshall, Kevin [Department of Physics and Astronomy, Widener University, Chester, PA 19013 (United States); Readhead, Anthony C. S.; Hovatta, Talvikki; King, Oliver, E-mail: maune@chara.gsu.edu [Cahill Laboratory of Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States)

    2014-10-10

    Simultaneous radio, optical (both photometry and polarimetry), X-ray, and γ-ray observations of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy J0849+5108 are presented. A massive three-magnitude optical flare across five nights in 2013 April is detected, along with associated flux increases in the γ-ray, infrared, and radio regimes; no comparable event was detected in the X-rays, though this may be due to poor coverage. A spectral energy distribution (SED) for the object using quasi-simultaneous data centered on the optical flare is compared to the previously published SEDs for the object by D'Ammando et al. The flare event coincided with a high degree of optical polarization. High amplitude optical microvariability is clearly detected, and is found to be of comparable amplitude when the object is observed in both faint and bright states. The object is also seen to undergo rapid shifts in polarization in both degree and electric vector position angle within a single night. J0849+5108 appears to show even more extreme variability than that previously reported for the similar object J0948+0022. These observations appear to support the growing claim that some RL-NLSy1 galaxies constitute a sub-class of blazar-like active galactic nuclei.

  16. The first γ-ray detection of the narrow-line Seyfert 1 FBQS J1644+2619

    D'Ammando, F.; Istituto Nazionale di Astrofisica; Orienti, M.; Larsson, J.; Giroletti, M.

    2015-01-01

    Here, we report the discovery of γ-ray emission from the narrow-line Seyfert 1 (NLSy1) galaxy FBQS J1644+2619 by the Large Area Telescope on board the Fermi satellite. The Third Fermi LAT Source catalogue reports an unidentified γ-ray source, detected over the first four years of Fermi operation, 0.°23 from the radio position of the NLSy1. Analysing 76 months of γ-ray data (2008 August 4–2014 December 31) we are able to better constrain the localization of the γ-ray source. The new position of the γ- ray source is 0.°05 from FBQS J1644+2619, suggesting a spatial association with the NLSy1. This is the sixth NLSy1 detected at high significance by Fermi-LAT so far. Notably, a significant increase of activity was observed in γ-rays from FBQS J1644+2619 during 2012 July–October, and an increase of activity in V -band was detected by the Catalina Real-Time Sky Survey in the same period.

  17. Investigation of local environment around rare earths (La and Eu) by fluorescence line narrowing during borosilicate glass alteration

    Molières, Estelle; Panczer, Gérard; Guyot, Yannick; Jollivet, Patrick; Majérus, Odile; Aschehoug, Patrick; Barboux, Philippe; Gin, Stéphane; Angeli, Frédéric

    2014-01-01

    The local environment of europium in soda-lime borosilicate glasses with a range of La 2 O 3 content was probed by continuous luminescence and Fluorescence Line Narrowing (FLN) to investigate the local environment of rare earth elements in pristine and leached glass. After aqueous leaching at 90 °C at pH 7 and 9.5, rare earths were fully retained and homogeneously distributed in the amorphous alteration layer (commonly called gel). Two separate silicate environments were observed in pristine and leached glasses regardless of the lanthanum content and the leaching conditions. A borate environment surrounding europium was not observed in pristine and leached glasses. During glass alteration, OH groups were located around the europium environment, which became more organized (higher symmetry) in the first coordination shell. -- Highlights: • No borate environment surrounding europium was detected in pristine borosilicate glasses. • Up to 12 mol% of REE2O3 in glass, local environment of europium does not significantly change. • Europium environment becomes more ordered and symmetric in gels than in pristine glasses. • Two distinct silicate sites were observed, as well in pristine glass as in gels (leached glasses). • In altered glasses, OH groups were located around europium

  18. Observation of soft X-ray spectra from a Seyfert 1 and a narrow emission-line galaxy

    Singh, K.P.; Garmire, G.P.; Nousek, J.

    1985-01-01

    The 0.2-40 keV X-ray spectra of the Seyfert 1 galaxy Mrk 509 and the narrow emission-line galaxy NGC 2992 are analyzed. The results suggest the presence of a steep soft X-ray component in Mrk 509 in addition to the well-known Gamma = 1.7 component found in other active galactic nuclei in the 2-40 keV energy range. The soft X-ray component is interpreted as due to thermal emission from a hot gas, probably associated with the highly ionized gas observed to be outflowing from the galaxy. The X-ray spectrum of NGC 2992 does not show any steepening in the soft X-ray band and is consistent with a single power law (Gamma = 1.78) with very low absorbing column density of 4 x 10 to the 21st/sq cm. A model with partial covering of the nuclear X-ray source is preferred, however, to a simple model with a single power law and absorption. 34 references

  19. The host galaxy of the gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    León Tavares, J.; Chavushyan, V.; Puerari, I.; Patiño-Alvarez, V.; Carramiñana, A.; Carrasco, L.; Guichard, J.; Olguín-Iglesias, A.; Valdes, J. [Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Apartado Postal 51 y 216, 72000 Puebla (Mexico); Kotilainen, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Väisäläntie 20, FI-21500 Piikkiö (Finland); Añorve, C. [Facultad de Ciencias de la Tierra y del Espacio (FACITE) de la Universidad Autónoma de Sinaloa, Blvd. de la Americas y Av. Universitarios S/N, Ciudad Universitaria, C.P. 80010, Culiacán Sinaloa (Mexico); Cruz-González, I. [Instituto de Astronomía, Universidad Nacional Autónoma de México, Ap. 70-264, 04510 DF (Mexico); Antón, S. [Instituto de Astrofísica de Andalucía-CSIC, E-18008 Granada (Spain); Karhunen, K.; Sanghvi, J., E-mail: leon.tavares@inaoep.mx [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-20100 Turku (Finland)

    2014-11-01

    We present optical and near-infrared (NIR) imaging data of the radio-loud, narrow-line Seyfert 1 galaxy 1H 0323+342, which shows intense and variable gamma-ray activity discovered by the Fermi satellite with the Large Area Telescope. Near-infrared and optical images are used to investigate the structural properties of the host galaxy of 1H 0323+342; this together with optical spectroscopy allows us to examine its black hole mass. Based on two-dimensional (2D) multiwavelength surface-brightness modeling, we find that statistically, the best model fit is a combination of a nuclear component and a Sérsic profile (n ∼ 2.8). However, the presence of a disk component (with a small bulge n ∼ 1.2) also remains a possibility and cannot be ruled out with the present data. Although at first glance a spiral-arm-like structure is revealed in our images, a 2D Fourier analysis of the imagery suggests that this structure corresponds to an asymmetric ring, likely associated with a recent violent dynamical interaction. We discuss our results in the context of relativistic jet production and galaxy evolution.

  20. The extreme behavior of the radio-loud narrow-line Seyfert 1 galaxy J0849+5108

    Maune, Jeremy D.; Eggen, Joseph R.; Miller, H. Richard; Marshall, Kevin; Readhead, Anthony C. S.; Hovatta, Talvikki; King, Oliver

    2014-01-01

    Simultaneous radio, optical (both photometry and polarimetry), X-ray, and γ-ray observations of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy J0849+5108 are presented. A massive three-magnitude optical flare across five nights in 2013 April is detected, along with associated flux increases in the γ-ray, infrared, and radio regimes; no comparable event was detected in the X-rays, though this may be due to poor coverage. A spectral energy distribution (SED) for the object using quasi-simultaneous data centered on the optical flare is compared to the previously published SEDs for the object by D'Ammando et al. The flare event coincided with a high degree of optical polarization. High amplitude optical microvariability is clearly detected, and is found to be of comparable amplitude when the object is observed in both faint and bright states. The object is also seen to undergo rapid shifts in polarization in both degree and electric vector position angle within a single night. J0849+5108 appears to show even more extreme variability than that previously reported for the similar object J0948+0022. These observations appear to support the growing claim that some RL-NLSy1 galaxies constitute a sub-class of blazar-like active galactic nuclei.

  1. The radio structure of the peculiar narrow-line Seyfert 1 galaxy candidate J1100+4421

    Gabányi, K. É.; Frey, S.; Paragi, Z.; Järvelä, E.; Morokuma, T.; An, T.; Tanaka, M.; Tar, I.

    2018-01-01

    Narrow-line Seyfert 1 galaxies (NLS1) are an intriguing subclass of active galactic nuclei. Their observed properties indicate low central black hole mass and high accretion rate. The extremely radio-loud NLS1 sources often show relativistic beaming and are usually regarded as younger counterparts of blazars. Recently, the object SDSS J110006.07+442144.3 was reported as a candidate NLS1 source. The characteristics of its dramatic optical flare indicated its jet-related origin. The spectral energy distribution of the object was similar to that of the γ-ray detected radio-loud NLS1, PMN J0948+0022. Our high-resolution European very long baseline interferometry network observations at 1.7 and 5 GHz revealed a compact core feature with a brightness temperature of ≳1010 K. Using the lowest brightness temperature value and assuming a moderate Lorentz factor of ∼9, the jet viewing angle is ≲26°. Archival Very Large Array data show a large-scale radio structure with a projected linear size of ∼150 kpc reminiscent of double-sided morphology.

  2. Investigation of local environment around rare earths (La and Eu) by fluorescence line narrowing during borosilicate glass alteration

    Molières, Estelle [CEA – DEN-DTCD-LCV-SECM Laboratoire d' études du Comportement à Long Terme, 30207 Bagnols-sur-Cèze (France); Panczer, Gérard; Guyot, Yannick [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne cedex (France); Jollivet, Patrick [CEA – DEN-DTCD-LCV-SECM Laboratoire d' études du Comportement à Long Terme, 30207 Bagnols-sur-Cèze (France); Majérus, Odile; Aschehoug, Patrick; Barboux, Philippe [Laboratoire de Chimie de la Matière Condensée de Paris, UMR-CNRS 7574, École Nationale Supérieure de Chimie de Paris (ENSCP Chimie-ParisTech), 11 rue Pierre et Marie Curie, 75231 Paris (France); Gin, Stéphane [CEA – DEN-DTCD-LCV-SECM Laboratoire d' études du Comportement à Long Terme, 30207 Bagnols-sur-Cèze (France); Angeli, Frédéric, E-mail: frederic.angeli@cea.fr [CEA – DEN-DTCD-LCV-SECM Laboratoire d' études du Comportement à Long Terme, 30207 Bagnols-sur-Cèze (France)

    2014-01-15

    The local environment of europium in soda-lime borosilicate glasses with a range of La{sub 2}O{sub 3} content was probed by continuous luminescence and Fluorescence Line Narrowing (FLN) to investigate the local environment of rare earth elements in pristine and leached glass. After aqueous leaching at 90 °C at pH 7 and 9.5, rare earths were fully retained and homogeneously distributed in the amorphous alteration layer (commonly called gel). Two separate silicate environments were observed in pristine and leached glasses regardless of the lanthanum content and the leaching conditions. A borate environment surrounding europium was not observed in pristine and leached glasses. During glass alteration, OH groups were located around the europium environment, which became more organized (higher symmetry) in the first coordination shell. -- Highlights: • No borate environment surrounding europium was detected in pristine borosilicate glasses. • Up to 12 mol% of REE2O3 in glass, local environment of europium does not significantly change. • Europium environment becomes more ordered and symmetric in gels than in pristine glasses. • Two distinct silicate sites were observed, as well in pristine glass as in gels (leached glasses). • In altered glasses, OH groups were located around europium.

  3. A Narrow-Linewidth Atomic Line Filter for Free Space Quantum Key Distribution under Daytime Atmospheric Conditions

    Brown, Justin; Woolf, David; Hensley, Joel

    2016-05-01

    Quantum key distribution can provide secure optical data links using the established BB84 protocol, though solar backgrounds severely limit the performance through free space. Several approaches to reduce the solar background include time-gating the photon signal, limiting the field of view through geometrical design of the optical system, and spectral rejection using interference filters. Despite optimization of these parameters, the solar background continues to dominate under daytime atmospheric conditions. We demonstrate an improved spectral filter by replacing the interference filter (Δν ~ 50 GHz) with an atomic line filter (Δν ~ 1 GHz) based on optical rotation of linearly polarized light through a warm Rb vapor. By controlling the magnetic field and the optical depth of the vapor, a spectrally narrow region can be transmitted between crossed polarizers. We find that the transmission is more complex than a single peak and evaluate peak transmission as well as a ratio of peak transmission to average transmission of the local spectrum. We compare filters containing a natural abundance of Rb with those containing isotopically pure 87 Rb and 85 Rb. A filter providing > 95 % transmission and Δν ~ 1.1 GHz is achieved.

  4. PROBING THE PHYSICS OF NARROW LINE REGIONS IN ACTIVE GALAXIES. II. THE SIDING SPRING SOUTHERN SEYFERT SPECTROSCOPIC SNAPSHOT SURVEY (S7)

    Dopita, Michael A.; Davies, Rebecca; Kewley, Lisa; Hampton, Elise; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Kharb, Preeti; Jose, Jessy; Bhatt, Harish; Ramya, S. [Indian Institute of Astrophysics, Koramangala 2 B Block, Bangalore 560034 (India); Scharwächter, Julia [LERMA, Observatoire de Paris, CNRS, UMR 8112, 61 Avenue de l’Observatoire, F-75014 Paris (France); Jin, Chichuan [Qian Xuesen Laboratory for Space Technology, Beijing (China); Banfield, Julie [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW, 1710 Australia (Australia); Zaw, Ingyin [New York University (Abu Dhabi), 70 Washington Square South, New York, NY 10012 (United States); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); James, Bethan [Institute of Astronomy, Cambridge University, Madingley Road, Cambridge CB3 0HA (United Kingdom); Srivastava, Shweta, E-mail: Michael.Dopita@anu.edu.au [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India)

    2015-03-15

    Here we describe the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) and present results on 64 galaxies drawn from the first data release. The S7 uses the Wide Field Spectrograph mounted on the ANU 2.3 m telescope located at the Siding Spring Observatory to deliver an integral field of 38 × 25 arcsec at a spectral resolution of R = 7000 in the red (530–710 nm), and R = 3000 in the blue (340–560 nm). From these data cubes we have extracted the narrow-line region spectra from a 4 arcsec aperture centered on the nucleus. We also determine the Hβ and [O iii] λ5007 fluxes in the narrow lines, the nuclear reddening, the reddening-corrected relative intensities of the observed emission lines, and the Hβ and [O iii] λ5007 luminosities determined from spectra for which the stellar continuum has been removed. We present a set of images of the galaxies in [O iii] λ5007, [N ii] λ6584, and Hα, which serve to delineate the spatial extent of the extended narrow-line region and also to reveal the structure and morphology of the surrounding H ii regions. Finally, we provide a preliminary discussion of those Seyfert 1 and Seyfert 2 galaxies that display coronal emission lines in order to explore the origin of these lines.

  5. Long term X-ray variability characteristics of the narrow-line Seyfert 1 galaxy RE J1034+396

    Chaudhury, K.; Chitnis, V. R.; Rao, A. R.; Singh, K. P.; Bhattacharyya, Sudip; Dewangan, G. C.; Chakraborty, S.; Chandra, S.; Stewart, G. C.; Mukerjee, K.; Dey, R. K.

    2018-05-01

    We present the results of our study of the long term X-ray variability characteristics of the Narrow Line Seyfert 1 galaxy RE J1034+396. We use data obtained from the AstroSat satellite along with the light curves obtained from XMM-Newton and Swift-XRT. We use the 0.3 - 7.0 keV and 3 - 20 keV data, respectively, from the SXT and the LAXPC of AstroSat. The X-ray spectra in the 0.3 - 20 keV region are well fit with a model consisting of a power-law and a soft excess described by a thermal-Compton emission with a large optical depth, consistent with the earlier reported results. We have examined the X-ray light curves in the soft and hard X-ray bands of SXT and LAXPC, respectively, and find that the variability is slightly larger in the hard band. To investigate the variability characteristics of this source at different time scales, we have used X-ray light curves obtained from XMM-Newton data (200 s to 100 ks range) and Swift-XRT data (1 day to 100 day range) and find that there are evidences to suggest that the variability sharply increases at longer time scales. We argue that the mass of the black hole in RE J1034+396 is likely to be ˜3 × 106 M⊙, based on the similarity of the observed QPO to the high frequency QPO seen in the Galactic black hole binary, GRS 1915+105.

  6. Embedded star formation in the extended narrow line region of Centaurus A: Extreme mixing observed by MUSE

    Santoro, F.; Oonk, J. B. R.; Morganti, R.; Oosterloo, T. A.; Tadhunter, C.

    2016-05-01

    We present a detailed study of the complex ionization structure in a small (~250 pc) extended narrow line region (ENLR) cloud near Centaurus A using the Multi Unit Spectroscopic Explorer. This cloud is located in the so-called outer filament of ionized gas (about 15 kpc from the nucleus) where jet-induced star formation has been suggested to occur by different studies. We find that, despite the small size, a mixture of ionization mechanisms is operating, resulting in considerable complexity in the spatial ionization structure. The area includes two H II regions where star formation is occurring and another location where star formation must have ceased very recently. Interestingly, the extreme Balmer decrement of one of the star forming regions (Hα/Hβobs ~ 6) indicates that it is still heavily embedded in its natal cocoon of gas and dust. At all three locations a continuum counterpart is found with spectra matching those of O/B stars local to Centaurus A. The H II regions are embedded in a larger gas complex which is photoionized by the radiation of the central active galactic nucleus (AGN), but the O/B stars affect the spatial ionization pattern in the ENLR cloud very locally. In particular, in the surroundings of the youngest star forming region, we can isolate a tight mixing sequence in the diagnostic diagram going from gas with ionization due to a pure stellar continuum to gas only photoionized by the AGN. These results emphasize the complexity and the mixture of processes occurring in star forming regions under the influence of an AGN radiation. This is relevant for our understanding of AGN-induced star formation suggested to occur in a number of objects, including this region of Centaurus A. They also illustrate that these young stars influence the gas over only a limited region.

  7. Electron paramagnetic resonance line shifts and line shape changes due to heisenberg spin exchange and dipole-dipole interactions of nitroxide free radicals in liquids 8. Further experimental and theoretical efforts to separate the effects of the two interactions.

    Peric, Mirna; Bales, Barney L; Peric, Miroslav

    2012-03-22

    The work in part 6 of this series (J. Phys. Chem. A 2009, 113, 4930), addressing the task of separating the effects of Heisenberg spin exchange (HSE) and dipole-dipole interactions (DD) on electron paramagnetic resonance (EPR) spectra of nitroxide spin probes in solution, is extended experimentally and theoretically. Comprehensive measurements of perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (pDT) in squalane, a viscous alkane, paying special attention to lower temperatures and lower concentrations, were carried out in an attempt to focus on DD, the lesser understood of the two interactions. Theoretically, the analysis has been extended to include the recent comprehensive treatment by Salikhov (Appl. Magn. Reson. 2010, 38, 237). In dilute solutions, both interactions (1) introduce a dispersion component, (2) broaden the lines, and (3) shift the lines. DD introduces a dispersion component proportional to the concentration and of opposite sign to that of HSE. Equations relating the EPR spectral parameters to the rate constants due to HSE and DD have been derived. By employing nonlinear least-squares fitting of theoretical spectra to a simple analytical function and the proposed equations, the contributions of the two interactions to items 1-3 may be quantified and compared with the same parameters obtained by fitting experimental spectra. This comparison supports the theory in its broad predictions; however, at low temperatures, the DD contribution to the experimental dispersion amplitude does not increase linearly with concentration. We are unable to deduce whether this discrepancy is due to inadequate analysis of the experimental data or an incomplete theory. A new key aspect of the more comprehensive theory is that there is enough information in the experimental spectra to find items 1-3 due to both interactions; however, in principle, appeal must be made to a model of molecular diffusion to separate the two. The permanent diffusion model is used to

  8. Electron-phonon coupling in solubilized LHC II complexes of green plants investigated by line-narrowing and temperature-dependent fluorescence spectroscopy

    Pieper, J K; Renger, G; Schödel, R; Voigt, J

    2001-01-01

    Line-narrowed and temperature-dependent fluorescence spectra are reported for the solubilized trimeric light-harvesting complex of Photosystem II (LHC II). Special attention has been paid to eliminate effects owing to reabsorption and to ensure that the line-narrowed fluorescence spectra are virtually unaffected by hole burning or scattering artifacts. Analysis of line-narrowed fluorescence spectra at 4.2 K indicates that the lowest Q//y-state of LHC II is characterized by weak electron-phonon coupling with a Huang-Rhys factor of similar to 0.9 and a broad and strongly asymmetric one- phonon profile with a peak frequency omega//m of 15 cm**-**1 and a width of Gamma = 105 cm**-**1. The 4.2 K fluorescence data are further consistent with the assignment of the lowest Q//y-state at similar to 680.0 nm and an inhomogeneous width of similar to 80 cm**- **1 gathered from a recent hole-burning study (Pieper et al. J. Phys. Chem. A 1999, 103, 2412). The temperature dependence of the fluorescence spectra of LHC II is s...

  9. Type 2 Active Galactic Nuclei with Double-peaked [O III] Lines. II. Single AGNs with Complex Narrow-line Region Kinematics are More Common than Binary AGNs

    Shen, Yue; Liu, Xin; Greene, Jenny E.; Strauss, Michael A.

    2011-07-01

    Approximately 1% of low-redshift (z interpreted as either due to kinematics, such as biconical outflows and/or disk rotation of the narrow line region (NLR) around single black holes, or due to the relative motion of two distinct NLRs in a merging pair of AGNs. Here, we report follow-up near-infrared (NIR) imaging and optical slit spectroscopy of 31 double-peaked [O III] type 2 AGNs drawn from the Sloan Digital Sky Survey (SDSS) parent sample presented in Liu et al. The NIR imaging traces the old stellar population in each galaxy, while the optical slit spectroscopy traces the NLR gas. These data reveal a mixture of origins for the double-peaked feature. Roughly 10% of our objects are best explained by binary AGNs at (projected) kpc-scale separations, where two stellar components with spatially coincident NLRs are seen. ~50% of our objects have [O III] emission offset by a few kpc, corresponding to the two velocity components seen in the SDSS spectra, but there are no spatially coincident double stellar components seen in the NIR imaging. For those objects with sufficiently high-quality slit spectra, we see velocity and/or velocity dispersion gradients in [O III] emission, suggestive of the kinematic signatures of a single NLR. The remaining ~40% of our objects are ambiguous and will need higher spatial resolution observations to distinguish between the two scenarios. Our observations therefore favor the kinematics scenario with a single AGN for the majority of these double-peaked [O III] type 2 AGNs. We emphasize the importance of combining imaging and slit spectroscopy in identifying kpc-scale binary AGNs, i.e., in no cases does one of these alone allow an unambiguous identification. We estimate that ~0.5%-2.5% of the z ~ 150 km s-1. Based in part on observations obtained with the 6.5 m Magellan telescopes located at Las Campanas Observatory, Chile, and with the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research

  10. Levitation in paramagnetic liquids

    Dunne, P.A. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland)]. E-mail: pdunne2@tcd.ie; Hilton, J. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland); Coey, J.M.D. [School of Physics and CRANN, Trinity Collge, Dublin 2 (Ireland)

    2007-09-15

    Magnetic levitation of diamagnetic and paramagnetic substances in a paramagnetic liquid is explored. Materials ranging from graphite to tin and copper can be made to float at ambient temperature in concentrated solutions of dysprosium nitrate, when an electromagnet or four-block permanent magnet array is used to produce a gradient field. Simulations illustrate the stable regions for levitation above the permanent magnets; and a novel eight-block configuration is proposed, which allows denser materials such as gold or lead to be levitated.

  11. Levitation in paramagnetic liquids

    Dunne, P.A.; Hilton, J.; Coey, J.M.D.

    2007-01-01

    Magnetic levitation of diamagnetic and paramagnetic substances in a paramagnetic liquid is explored. Materials ranging from graphite to tin and copper can be made to float at ambient temperature in concentrated solutions of dysprosium nitrate, when an electromagnet or four-block permanent magnet array is used to produce a gradient field. Simulations illustrate the stable regions for levitation above the permanent magnets; and a novel eight-block configuration is proposed, which allows denser materials such as gold or lead to be levitated

  12. Probing the Physics of Narrow-line Regions in Active Galaxies. IV. Full Data Release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7)

    Thomas, Adam D.; Dopita, Michael A.; Davies, Rebecca; Hampton, Elise; Kewley, Lisa; Banfield, Julie; Groves, Brent; Sutherland, Ralph [RSAA, Australian National University, Cotter Road, Weston Creek, ACT 2611 (Australia); Shastri, Prajval; Sairam, Lalitha [Indian Institute of Astrophysics, Sarjapur Road, Bengaluru 560034 (India); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Jin, Chichuan [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Juneau, Stéphanie [CEA-Saclay, DSM/IRFU/SAp, F-91191 Gif-sur-Yvette (France); Kharb, Preeti [National Centre for Radio Astrophysics—Tata Institute of Fundamental Research, Pune University Campus, Post Bag 3, Ganeshkhind Pune 411007 (India); Scharwächter, Julia [Gemini Observatory, Northern Operations Center, 670 N. A’ohoku Place, Hilo, Hawaii 96720 (United States); Shalima, P. [Regional Institute of Education, Manasagangotri, Mysore 570006 (India); Sundar, M. N. [Jain University, 3rd Block Jayanagar, Bengaluru 560011 (India); Zaw, Ingyin, E-mail: adam.thomas@anu.edu.au [New York University (Abu Dhabi), 70 Washington Sq. S, New York, NY 10012 (United States)

    2017-09-01

    We present the second and final data release of the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7). Data are presented for 63 new galaxies not included in the first data release, and we provide 2D emission-line fitting products for the full S7 sample of 131 galaxies. The S7 uses the WiFeS instrument on the ANU 2.3 m telescope to obtain spectra with a spectral resolution of R  = 7000 in the red (540–700 nm) and R  = 3000 in the blue (350–570 nm), over an integral field of 25 × 38 arcsec{sup 2} with 1 × 1 arcsec{sup 2} spatial pixels. The S7 contains both the largest sample of active galaxies and the highest spectral resolution of any comparable integral field survey to date. The emission-line fitting products include line fluxes, velocities, and velocity dispersions across the WiFeS field of view, and an artificial neural network has been used to determine the optimal number of Gaussian kinematic components for emission-lines in each spaxel. Broad Balmer lines are subtracted from the spectra of nuclear spatial pixels in Seyfert 1 galaxies before fitting the narrow lines. We bin nuclear spectra and measure reddening-corrected nuclear fluxes of strong narrow lines for each galaxy. The nuclear spectra are classified on optical diagnostic diagrams, where the strength of the coronal line [Fe vii] λ 6087 is shown to be correlated with [O iii]/H β . Maps revealing gas excitation and kinematics are included for the entire sample, and we provide notes on the newly observed objects.

  13. Narrow-line external cavity diode laser micro-packaging in the NIR and MIR spectral range

    Jiménez, A.; Milde, T.; Staacke, N.; Aßmann, C.; Carpintero, G.; Sacher, J.

    2017-07-01

    Narrow-linewidth tunable diode lasers are an important tool for spectroscopic instrumentation. Conventional external cavity diode lasers offer high output power and narrow linewidth. However, most external cavity diode lasers are designed as laboratory instrument and do not allow portability. In comparison, other commonly used lasers, like distributed feedback lasers (DFB) that are capable of driving a handheld device, are limited in power and show linewidths which are not sufficiently narrow for certain applications. We present new miniaturized types of tunable external cavity diode laser which overcome the drawbacks of conventional external cavity diode lasers and which preserve the advantages of this laser concept. Three different configurations are discussed in this article. The three types of miniaturized external cavity diode laser systems achieve power values of more than 50 mW within the 1.4 μm water vapor absorption band with excellent side-mode suppression and linewidth below 100 kHz. Typical features outstand with respect to other type of laser systems which are of extended use such as DFB laser diodes. The higher output power and the lower linewidth will enable a higher sensitivity and resolution for a wide range of applications.

  14. Paramagnetic defects in hydrogenated amorphous carbon powders

    Keeble, D J; Robb, K M; Smith, G M; Mkami, H El; Rodil, S E; Robertson, J

    2003-01-01

    Hydrogenated amorphous carbon materials typically contain high concentrations of paramagnetic defects, the density of which can be quantified by electron paramagnetic resonance (EPR). In this work EPR measurements near 9.5, 94, and 189 GHz have been performed on polymeric and diamond-like hydrogenated amorphous carbon (a-C:H) powder samples. A similar single resonance line was observed at all frequencies for the two forms of a-C:H studied. No contributions to the spectrum from centres with resolved anisotropic g-values as reported earlier were detected. An increase in linewidth with microwave frequency was observed. Possible contributions to this frequency dependence are discussed

  15. Electron Paramagnetic Resonance Spectroscopy

    Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 11. Electron Paramagnetic Resonance Spectroscopy: Biological Applications. B G Hegde. General Article Volume 20 Issue 11 November 2015 pp 1017-1032. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Electron Paramagnetic Resonance Imaging

    Twentieth century bore witness to remarkable scientists whohave advanced our understanding of the brain. Among them,EPR (Electron Paramagnetic Resonance) imaging is particularlyuseful in monitoring hypoxic zones in tumors which arehighly resistant to radiation and chemotherapeutic treatment.This first part of the ...

  17. Diagnosing the Kinematics of the Tori in Active Galactic Nuclei with the Velocity-resolved Reverberation Mapping of the Narrow Iron K α Line

    Liu Yuan; Li Xiaobo, E-mail: liuyuan@ihep.ac.cn, E-mail: lixb@ihep.ac.cn [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Sciences, P.O. Box 918-3, Beijing 100049 (China)

    2017-07-20

    The properties of the dusty tori in active galactic nuclei (AGNs) have been investigated in detail, mainly focusing on the geometry and components; however, the kinematics of the torus are still not clear. The narrow iron K α line at 6.4 keV is thought to be produced by the X-ray reflection from the torus. Thus, the velocity-resolved reverberation mapping of it is able to constrain the kinematics of the torus. Such effort is limited by the spectral resolution of current charged coupled device (CCD) detectors and should be possible with the microcalorimeter on the next generation X-ray satellite. In this paper, we first construct the response functions of the torus under a uniform inflow, a Keplerian rotation, and a uniform outflow. Then the energy-dependent light curve of the narrow iron K α line is simulated according to the performance of the X-ray Integral Field Unit in Athena. Finally, the energy-dependent cross-correlation function is calculated to reveal the kinematic signal. According to our results, 100 observations with 5 ks exposure of each are sufficient to distinguish the above three velocity fields. Although the real geometry and velocity field of the torus could be more complex than we assumed, the present result proves the feasibility of the velocity-resolved reverberation mapping of the narrow iron K α line. The combination of the dynamics of the torus with those of the broad-line region and the host galaxy is instructive for the understanding of the feeding and feedback process of AGNs.

  18. Narrow-line, cw orange light generation in a diode-pumped Nd:YVO4 laser using volume Bragg gratings.

    Chen, Y L; Chen, W W; Du, C E; Chang, W K; Wang, J L; Chung, T Y; Chen, Y H

    2009-12-07

    We report on the demonstration of a narrow-line, cw orange 593-nm laser achieved via intracavity sum-frequency generation (SFG) of a diode-pumped dual-wavelength (1064 and 1342 nm) Nd:YVO(4) laser using two volume Bragg grating (VBG) reflectors. At diode pump power of up to 3.6 W, the 593-nm intracavity SFG laser radiates at the single longitudinal mode of spectral linewidth as narrow as approximately 15 MHz. More than 23-mW single-longitudinal-mode or 40-mW, diode pump power) 593-nm orange lights can be obtained from this compact laser system. Spectral tuning of the orange light was performed via the temperature tuning of the two VBGs in this system, achieving an effective tuning rate of ~5 pm/degrees C.

  19. Demonstrating Paramagnetism Using Liquid Nitrogen.

    Simmonds, Ray; And Others

    1994-01-01

    Describes how liquid nitrogen is attracted to the poles of neodymium magnets. Nitrogen is not paramagnetic, so the attraction suggests that the liquid nitrogen contains a small amount of oxygen, which causes the paramagnetism. (MVL)

  20. Fermi LAT Detection of a GeV Flare from the Radio-Loud Narrow-Line Sy1 1H 0323+342

    Carpenter, Bryce; Ojha, Roopesh

    2013-08-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with 1H 0323+342 (RA=03h24m41.1613s, Dec=+34d10m45.856s, J2000; Beasley et al. 2002, ApJS, 141, 13) at z= 0.061 (Marcha et al. 1996, MNRAS, 281, 425). This is the second nearest radio-loud Narrow-Line Seyfert 1 galaxy, a small and important class of gamma-ray loud AGN (Abdo et al.

  1. Paramagnetic contrast material

    McNamara, M.T.

    1987-01-01

    Paramagnetic contrast materials have certainly demonstrated clinical utility in a variety of organ systems for improved detection of various neoplastic, inflammatory, infectious, and physiologic abnormalities. Although the more commonly employed extracellular agents, such as Gd-DTPA, have been quite safe and useful, particularly in the CNS, it is almost certain that other substances will achieve more success in various other organs, such as iron oxides in the reticuloendothelial system and persisting extracellular agents in the cardiovascular system. Finally, as MRI technology continues to evolve, producing such exciting new sequences as gradient-echo fast scans, the roles of currently existing and newly discovered paramagnetic pharmaceuticals must be continuously reevaluated both to obtain maximum clinical benefit and to guide the search for newer agents that may further optimize the diagnostic efficacy of MRI

  2. On kinetics of paramagnetic radiation defects accumulation in beryllium ceramics

    Polyakov, A.I.; Ryabikin, Yu.A.; Zashkvara, O.V.; Bitenbaev, M.I.; Petykhov, Yu.V.

    1999-01-01

    Results of paramagnetic radiation defects concentration dependence study in beryllium ceramics from gamma-irradiation dose ( 60 Co) within interval 0-100 Mrem are cited. Obtained dose dependence has form of accumulation curve with saturation typical of for majority of solids (crystals, different polymers, organic substances and others) , in which under irradiation occur not only formation of paramagnetic radiation defects, but its destruction due to recombination and interaction with radiation fields. Analysis of accumulation curve by the method of distant asymptotics allows to determine that observed in gamma-irradiated beryllium ceramics double line of electron spin resonance is forming of two types of paramagnetic radiation defects. It was defined, that sum paramagnetic characteristics of beryllium ceramics within 1-100 Mrad gamma- irradiation dose field change insignificantly and define from first type of paramagnetic radiation defects

  3. DISCOVERY OF DRAMATIC OPTICAL VARIABILITY IN SDSS J1100+4421: A PECULIAR RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXY?

    Tanaka, Masaomi [National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Morokuma, Tomoki; Doi, Mamoru; Kikuchi, Yuki [Institute of Astronomy, School of Science, University of Tokyo, Mitaka, Tokyo 181-0015 (Japan); Itoh, Ryosuke [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Akitaya, Hiroshi; Tanaka, Yasuyuki T.; Kawabata, Koji S. [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Tominaga, Nozomu [Department of Physics, Faculty of Science and Engineering, Konan University, Kobe, Hyogo 658-8501 (Japan); Saito, Yoshihiko; Kawai, Nobuyuki [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan); Stawarz, Łukasz [Institute of Space and Astronautical Science, JAXA, Sagamihara, Kanagawa 252-5210 (Japan); Gandhi, Poshak [Department of Physics, Durham University, Durham DH1-3LE (United Kingdom); Ali, Gamal; Essam, Ahmad; Hamed, Gamal [National Research Institute of Astronomy and Geophysics, Helwan, Cairo (Egypt); Aoki, Tsutomu [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, Kiso, Nagano 397-0101 (Japan); Contreras, Carlos; Hsiao, Eric Y. [Carnegie Observatories, Las Campanas Observatory, Colina El Pino, Casilla 601 (Chile); Iwata, Ikuru, E-mail: masaomi.tanaka@nao.ac.jp [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); and others

    2014-10-01

    We present our discovery of dramatic variability in SDSS J1100+4421 by the high-cadence transient survey Kiso Supernova Survey. The source brightened in the optical by at least a factor of three within about half a day. Spectroscopic observations suggest that this object is likely a narrow-line Seyfert 1 galaxy (NLS1) at z = 0.840, however, with unusually strong narrow emission lines. The estimated black hole mass of ∼10{sup 7} M {sub ☉} implies bolometric nuclear luminosity close to the Eddington limit. SDSS J1100+4421 is also extremely radio-loud, with a radio loudness parameter of R ≅ 4 × 10{sup 2}-3 × 10{sup 3}, which implies the presence of relativistic jets. Rapid and large-amplitude optical variability of the target, reminiscent of that found in a few radio- and γ-ray-loud NLS1s, is therefore produced most likely in a blazar-like core. The 1.4 GHz radio image of the source shows an extended structure with a linear size of about 100 kpc. If SDSS J1100+4421 is a genuine NLS1, as suggested here, this radio structure would then be the largest ever discovered in this type of active galaxies.

  4. A TALE OF TWO NARROW-LINE REGIONS: IONIZATION, KINEMATICS, AND SPECTRAL ENERGY DISTRIBUTIONS FOR A LOCAL PAIR OF MERGING OBSCURED ACTIVE GALAXIES

    Hainline, Kevin N.; Hickox, Ryan C.; Chen, Chien-Ting; Carroll, Christopher M.; Jones, Mackenzie L.; Zervos, Alexandros S. [Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Goulding, Andrew D. [Department Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2016-05-20

    We explore the gas ionization and kinematics, as well as the optical-IR spectral energy distributions for UGC 11185, a nearby pair of merging galaxies hosting obscured active galactic nuclei (AGNs), also known as SDSS J181611.72+423941.6 and J181609.37+423923.0 (J1816NE and J1816SW, z ≈ 0.04). Due to the wide separation between these interacting galaxies (∼23 kpc), observations of these objects provide a rare glimpse of the concurrent growth of supermassive black holes at an early merger stage. We use BPT line diagnostics to show that the full extent of the narrow-line emission in both galaxies is photoionized by an AGN, and confirm the existence of a 10 kpc-scale ionization cone in J1816NE, while in J1816SW the AGN narrow-line region is much more compact (1–2 kpc) and relatively undisturbed. Our observations also reveal the presence of ionized gas that nearly spans the entire distance between the galaxies, which is likely in a merger-induced tidal stream. In addition, we carry out a spectral analysis of the X-ray emission using data from XMM-Newton . These galaxies represent a useful pair to explore how the [O iii] luminosity of an AGN is dependent on the size of the region used to explore the extended emission. Given the growing evidence for AGN “flickering” over short timescales, we speculate that the appearances and impacts of these AGNs may change multiple times over the course of the galaxy merger, which is especially important given that these objects are likely the progenitors of the types of systems commonly classified as “dual AGNs.”.

  5. Adsorption and collective paramagnetism

    Selwood, Pierce W

    1962-01-01

    Adsorption and Collective Paramagnetism describes a novel method for studying chemisorption. The method is based on the change in the number of unpaired electrons in the adsorbent as chemisorption occurs. The method is applicable to almost all adsorbates, but it is restricted to ferromagnetic adsorbents such as nickel, which may be obtained in the form of very small particles, that is to say, to ferromagnetic adsorbents with a high specific surface. While almost all the data used illustratively have been published elsewhere this is the first complete review of the subject. The book is addresse

  6. A tunable narrow-line-width multi-wavelength Er-doped fiber laser based on a high birefringence fiber ring mirror and an auto-tracking filter

    Jia, Xiu-jie; Liu, Yan-ge; Si, Li-bin; Guo, Zhan-cheng; Fu, Sheng-gui; Kai, Gui-yun; Dong, Xiao-yi

    2008-01-01

    A novel multi-wavelength erbium-doped fiber laser operating in C-band is proposed and successfully demonstrated. The wavelength interval between the wavelengths is about 0.22 nm. The 3 dB bandwidth of the laser is about 0.012 nm, and the output power reaches 4.8 mW. By using a high birefringence fiber ring mirror (HiBi-FLM) and a tunable FBG, the laser realizes switchable and tunable characteristic. The mode hopping can be effectively prevented. Moreover, this laser can improve wavelength stability significantly by taking advantage of an un-pumped Er3+-doped fiber at the standing-wave section. The laser can operate in stable narrow-line-width with single-, dual-wavelength, and unstable triple-wavelength output at room temperature.

  7. X-ray monitoring of the radio and γ-ray loud Narrow-Line Seyfert 1 Galaxy PKS2004–447

    Kreikenbohm A.

    2013-12-01

    Full Text Available We present preliminary results of the X-ray analysis of XMM-Newton and Swift observations as part of a multi-wavelength monitoring campaign in 2012 of the radio-loud narrow line Seyfert 1 galaxy PKS 2004–447. The source was recently detected in γ-rays by Fermi/LAT among only four other galaxies of that type. The 0:5 – 10 keV X-ray spectrum is well-described by a simple absorbed powerlaw (Γ ∼ 1.6. The source brightness exhibits variability on timescales of months to years with indications for spectral variability, which follows a “bluer-when-brighter” behaviour, similar to blazars.

  8. FERMI/LARGE AREA TELESCOPE DISCOVERY OF GAMMA-RAY EMISSION FROM A RELATIVISTIC JET IN THE NARROW-LINE QUASAR PMN J0948+0022

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Bloom, E. D.; Borgland, A. W.; Axelsson, M.; Battelino, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Baughman, B. M.; Bonamente, E.; Brigida, M.; Caliandro, G. A.; Bruel, P.

    2009-01-01

    We report the discovery by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope of high-energy γ-ray emission from the peculiar quasar PMN J0948+0022 (z = 0.5846). The optical spectrum of this object exhibits rather narrow Hβ (FWHM(Hβ) ∼1500 km s -1 ), weak forbidden lines, and is therefore classified as a narrow-line type I quasar. This class of objects is thought to have relatively small black hole mass and to accrete at a high Eddington ratio. The radio loudness and variability of the compact radio core indicate the presence of a relativistic jet. Quasi-simultaneous radio/optical/X-ray and γ-ray observations are presented. Both radio and γ-ray emissions (observed over five months) are strongly variable. The simultaneous optical and X-ray data from Swift show a blue continuum attributed to the accretion disk and a hard X-ray spectrum attributed to the jet. The resulting broadband spectral energy distribution (SED) and, in particular, the γ-ray spectrum measured by Fermi are similar to those of more powerful Flat-Spectrum Radio Quasars (FSRQs). A comparison of the radio and γ-ray characteristics of PMN J0948+0022 with the other blazars detected by LAT shows that this source has a relatively low radio and γ-ray power with respect to other FSRQs. The physical parameters obtained from modeling the SED also fall at the low power end of the FSRQ parameter region discussed in Celotti and Ghisellini. We suggest that the similarity of the SED of PMN J0948+0022 to that of more massive and more powerful quasars can be understood in a scenario in which the SED properties depend on the Eddington ratio rather than on the absolute power.

  9. Simultaneous NuSTAR and XMM-Newton 0.5-80 keV spectroscopy of the narrow-line Seyfert 1 galaxy SWIFT J2127.4+5654

    Marinucci, A.; Matt, G.; Kara, E.

    2014-01-01

    We present a broad-band spectral analysis of the joint XMM-Newton and Nuclear Spectroscopic Telescope Array observational campaign of the narrow-line Seyfert 1 SWIFT J2127.4+5654, consisting of 300 ks performed during three XMM-Newton orbits. We detect a relativistic broadened iron Kα line...

  10. Induced Orbital Paramagnetism and Paratropism in Closed-Shell Molecules

    Pelloni, Stefano; Lazzeretti, Paolo; Zanasi, Riccardo

    2009-07-01

    Three-dimensional models of the quantum-mechanical current density induced by a uniform magnetic field in the electron cloud have been obtained for closed-shell systems BeH-, BH, and CH+, characterized by induced orbital paramagnetism, and in planar unsaturated hydrocarbons C4H4 and clamped C8H8, exhibiting π paramagnetism. It is shown that, even for these paramagnetic systems, the paramagnetic contributions to magnetic susceptibilities and nuclear magnetic shielding, customarily taken into account in perturbation theory approaches, can formally be eliminated via the procedure of continuous transformation of the origin of the current density-paramagnetic zero. The definition of magnetic response properties can therefore be recast as a sum of two formally "diamagnetic" terms for any molecule, including systems showing strong induced orbital paramagnetism. It is shown that the paramagnetism in the compounds studied arises from the nodal topology of the electronic wave function. In particular, paratropic vortices circulate about stagnation lines at the intersection of nodal surfaces of the highest-occupied zero-order molecular orbital and corresponding first-order orbital.

  11. RAPID INFRARED VARIABILITY OF THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES: A VIEW FROM THE WIDE-FIELD INFRARED SURVEY EXPLORER

    Jiang Ning; Zhou Hongyan; Wang Tinggui; Dong Xiaobo; Jiang Peng [Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Science, Hefei, Anhui 230026 (China); Ho, Luis C. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Yuan Weimin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Ji Tuo; Tian Qiguo, E-mail: jnac@mail.ustc.edu.cn [Polar Research Institute of China, 451 Jinqiao Road, Pudong, Shanghai 200136 (China)

    2012-11-10

    Using newly released data from the Wide-field Infrared Survey Explorer, we report the discovery of rapid infrared variability in three radio-loud narrow-line Seyfert 1 galaxies (NLS1s) selected from the 23 sources in the sample of Yuan et al. J0849+5108 and J0948+0022 clearly show intraday variability, while J1505+0326 has a longer measurable timescale within 180 days. Their variability amplitudes, corrected for measurement errors, are {approx}0.1-0.2 mag. The detection of intraday variability restricts the size of the infrared-emitting region to {approx}10{sup -3} pc, significantly smaller than the scale of the torus but consistent with the base of a jet. The three variable sources are exceptionally radio-loud, have the highest radio brightness temperature among the whole sample, and all show detected {gamma}-ray emission in Fermi/LAT observations. Their spectral energy distributions resemble those of low-energy-peaked blazars, with a synchrotron peak around infrared wavelengths. This result strongly confirms the view that at least some radio-loud NLS1s are blazars with a relativistic jet close to our line of sight. The beamed synchrotron emission from the jet contributes significantly to and probably dominates the spectra in the infrared and even optical bands.

  12. STRONG UV AND X-RAY VARIABILITY OF THE NARROW LINE SEYFERT 1 GALAXY WPVS 007-ON THE NATURE OF THE X-RAY LOW STATE

    Grupe, Dirk; Barlow, Brad N. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Komossa, S. [Max-Planck-Institut fuer Radioastronomie, Auf dem Huegel 69, D-53121 Bonn (Germany); Scharwaechter, Julia [Research School of Astronomy and Astrophysics, Australian National University, Mount Stromlo Observatory, Cotter Road, Weston Creek, ACT 2611 (Australia); Dietrich, Matthias [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Leighly, Karen M.; Lucy, Adrian, E-mail: dxg35@psu.edu, E-mail: julia.scharwaechter@obspm.fr, E-mail: leighly@nhn.ou.edu [Homer L. Dodge Department of Physics and Astronomy, University of Oklahoma, 440 West Brooks Street, Norman, OK 73019 (United States)

    2013-10-01

    We report on multi-wavelength observations of the X-ray transient Narrow Line Seyfert 1 (NLS1) galaxy WPVS 007. The galaxy was monitored with Swift between 2005 October and 2013 July, after it had previously undergone a dramatic drop in its X-ray flux. For the first time, we are able to repeatedly detect this NLS1 in X-rays again. This increased number of detections in the last couple of years may suggest that the strong absorber that has been found in this active galactic nucleus (AGN) is starting to become leaky and may eventually disappear. The X-ray spectra obtained for WPVS 007 are all consistent with a partial covering absorber model. A spectrum based on the data during the extreme low X-ray flux states shows that the absorption column density is of the order of 4 Multiplication-Sign 10{sup 23} cm{sup -2} with a covering fraction of 95%. WPVS 007 also displays one of the strongest UV variabilities seen in NLS1s. The UV continuum variability anti-correlates with the optical/UV slope {alpha}{sub UV}, which suggests that the variability may be primarily due to reddening. The UV variability timescales are consistent with moving dust ''clouds'' located beyond the dust sublimation radius of R{sub sub} Almost-Equal-To 20 lt-days. We present for the first time near-infrared JHK data of WPVS 007, which reveal a rich emission-line spectrum. Recent optical spectroscopy does not indicate significant variability in the broad permitted and Fe II emission lines, implying that the ionizing continuum seen by those gas clouds has not significantly changed over the last decades. All X-ray and UV observations are consistent with a scenario in which an evolving broad absorption line (BAL) flow obscures the continuum emission. As such, WPVS 007 is an important target for our understanding of BAL flows in low-mass AGNs.

  13. Broadband spectral study of the jet-disc emission in the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342

    Ghosh, Ritesh; Dewangan, Gulab C.; Mallick, Labani; Raychaudhuri, Biplab

    2018-06-01

    We present a broadband spectral study of the radio-loud narrow-line Seyfert 1 galaxy 1H 0323+342 based on multi-epoch observations performed with NuSTAR on 2014 March 15, and two simultaneous observations performed with Suzaku and Swift on 2009 July 26 and 2013 March 1. We found the presence of a strong soft X-ray excess emission, a broad but weak Fe line and hard X-ray excess emission. We used the blurred reflection (relxill) and the intrinsic disc Comptonization (optxagnf), two physically motivated models, to describe the broadband spectra and to disentangle the disk/corona and jet emission. The relxill model is mainly constrained by the strong soft X-ray excess although the model failed to predict this excess when fitted above 3{keV} and extrapolated to lower energies. The joint spectral analysis of the three datasets above 3{keV} with this model resulted in a high black hole spin (a > 0.9) and moderate reflection fraction R ˜ 0.5. The optxagnf model fitted to the two simultaneous datasets resulted in an excess emission in the UV band. The simultaneous UV-to-hard X-ray spectra of 1H 0323+342 are best described by a model consisting of a primary X-ray power-law continuum with Γ ˜ 1.8, a blurred reflection component with R ˜ 0.5, Comptonised disk emission as the soft X-ray excess, optical/UV emission from a standard accretion disk around a black hole of mass ˜107M⊙ and a steep power law (Γ ˜ 3 - 3.5) component, most likely the jet emission in the UV band. The fractional RMS variability spectra suggest that both the soft excess and the powerlaw component are variable in nature.

  14. FBQS J1644+2619: multiwavelength properties and its place in the class of γ-ray emitting Narrow Line Seyfert 1s

    Larsson, J.; D'Ammando, F.; Falocco, S.; Giroletti, M.; Orienti, M.; Piconcelli, E.; Righini, S.

    2018-05-01

    A small fraction of Narrow Line Seyfert 1s (NLSy1s) are observed to be γ-ray emitters. Understanding the properties of these sources is of interest since the majority of NLSy1s are very different from typical blazars. Here, we present a multifrequency analysis of FBQS J1644+2619, one of the most recently discovered γ-ray emitting NLSy1s. We analyse an ˜80 ks XMM-Newton observation obtained in 2017, as well as quasi-simultaneous multiwavelength observations covering the radio-γ-ray range. The spectral energy distribution of the source is similar to the other γ-ray NLSy1s, confirming its blazar-like nature. The X-ray spectrum is characterized by a hard photon index (Γ = 1.66) above 2 keV and a soft excess at lower energies. The hard photon index provides clear evidence that inverse Compton emission from the jet dominates the spectrum, while the soft excess can be explained by a contribution from the underlying Seyfert emission. This contribution can be fitted by reflection of emission from the base of the jet, as well as by Comptonization in a warm, optically thick corona. We discuss our results in the context of the other γ-ray NLSy1s and note that the majority of them have similar X-ray spectra, with properties intermediate between blazars and radio-quiet NLSy1s.

  15. JET PROPERTIES OF GeV-SELECTED RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES AND POSSIBLE CONNECTION TO THEIR DISK AND CORONA

    Sun, Xiao-Na; Lin, Da-Bin; Liang, En-Wei [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Zhang, Jin [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Xue, Zi-Wei; Zhang, Shuang-Nan, E-mail: zhang.jin@hotmail.com [Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences, Kunming 650011 (China)

    2015-01-01

    The observed spectral energy distributions of five GeV-selected narrow-line Seyfert 1 (NLS1) galaxies are fitted with a model including the radiation ingredients from the relativistic jet, the accretion disk, and the corona. We compare the properties of these GeV NLS1 galaxies with flat spectrum radio quasars (FSRQs), BL Lacertae objects (BL Lacs), and radio-quiet (RQ) Seyfert galaxies, and explore possible hints for jet-disk/corona connection. Our results show that the radiation physics and the jet properties of the GeV NLS1 galaxies resemble that of FSRQs. The luminosity variations of PMN J0948+0022 and 1H 0323+342 at the GeV band is tightly correlated with the beaming factor (δ), similar to that observed in FSRQ 3C 279. The accretion disk luminosities and the jet powers of the GeV NLS1 galaxies cover both the ranges of FSRQs and BL Lacs. With the detection of bright corona emission in 1H 0323+342, we show that the ratio of the corona luminosity (L {sub corona}) to the accretion disk luminosity (L {sub d}) is marginally within the high end of this ratio distribution for an RQ Seyfert galaxy sample, and the variation of jet luminosity may connect with L {sub corona}. However, it is still unclear whether a system with a high L {sub corona}/L {sub d} ratio prefers to power a jet.

  16. MINUTE-SCALE RAPID VARIABILITY OF THE OPTICAL POLARIZATION IN THE NARROW-LINE SEYFERT 1 GALAXY PMN J0948+0022

    Itoh, Ryosuke; Tanaka, Yasuyuki T.; Fukazawa, Yasushi; Kawaguchi, Kenji; Takaki, Katsutoshi; Ueno, Issei [Department of Physical Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Kawabata, Koji S.; Moritani, Yuki; Uemura, Makoto; Akitaya, Hiroshi; Yoshida, Michitoshi; Ohsugi, Takashi [Hiroshima Astrophysical Science Center, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Hanayama, Hidekazu; Miyaji, Takeshi [Ishigakijima Astronomical Observatory, National Astronomical Observatory of Japan, 1024-1 Arakawa, Ishigaki, Okinawa 907-0024 (Japan); Kawai, Nobuyuki, E-mail: itoh@hep01.hepl.hiroshima-u.ac.jp [Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)

    2013-09-20

    We report on optical photopolarimetric results of the radio-loud narrow-line Seyfert 1 (RL-NLSy1) galaxy PMN J0948+0022 on 2012 December to 2013 February triggered by flux enhancements in the near infrared and γ-ray bands. With the one-shot polarimetry of the Hiroshima One-shot Wide field Polarimeter installed on the Kanata Telescope, we detected very rapid variability in the polarized-flux (PF) light curve on MJD 56281 (2012 December 20). The rise and decay times were about 140 s and 180 s, respectively. The polarization degree (PD) reached 36% ± 3% at the peak of the short-duration pulse, while the polarization angle remained almost constant. In addition, temporal profiles of the total flux and PD showed highly variable but well correlated behavior and discrete correlation function analysis revealed that no significant time lag of more than 10 minutes was present. The high PD and minute-scale variability in PF provides clear evidence of synchrotron radiation from a very compact emission region of ∼10{sup 14} cm size with a highly ordered magnetic field. Such micro-variability of polarization is also observed in several blazar jets, but its complex relation between total flux and PD are explained by a multi-zone model in several blazars. The implied single emission region in PMN J0948+0022 might reflect a difference of jets between RL-NLSy1s and blazars.

  17. VERY LONG BASELINE ARRAY IMAGING OF PARSEC-SCALE RADIO EMISSIONS IN NEARBY RADIO-QUIET NARROW-LINE SEYFERT 1 GALAXIES

    Doi, Akihiro [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuou-ku, Sagamihara, Kanagawa 252-5210 (Japan); Asada, Keiichi; Inoue, Makoto [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Fujisawa, Kenta [The Research Institute of Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Nagai, Hiroshi; Hagiwara, Yoshiaki [National Astronomical Observatory, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Wajima, Kiyoaki, E-mail: akihiro.doi@vsop.isas.jaxa.jp [Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China)

    2013-03-01

    We conducted Very Long Baseline Array (VLBA) observations of seven nearby narrow-line Seyfert 1 (NLS1) galaxies at 1.7 GHz ({lambda}18 cm) with milliarcsecond resolution. This is the first systematic very long baseline interferometry study focusing on the central parsec-scale regions of radio-quiet NLS1s. Five of the seven were detected at a brightness temperature of {approx}> 5 Multiplication-Sign 10{sup 6} K and contain radio cores with high brightness temperatures of >6 Multiplication-Sign 10{sup 7} K, indicating a nonthermal process driven by jet-producing central engines as in radio-loud NLS1s and other active galactic nucleus classes. VLBA images of MRK 1239, MRK 705, and MRK 766 exhibit parsec-scale jets with clear linear structures. A large portion of the radio power comes from diffuse emission components that are distributed within the nuclear regions ({approx}< 300 pc), which is a common characteristic throughout the observed NLS1s. Jet kinetic powers limited by the Eddington limit may be insufficient to allow the jets to escape to kiloparsec scales for these radio-quiet NLS1s with low-mass black holes of {approx}< 10{sup 7} M {sub Sun }.

  18. EPR in characterization of seeds paramagnetic species

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C.

    2011-01-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe 2 O 3 ), magnetite (Fe 3 O 4 ), and ferrihydrite (Fe 5 HO 8 · 4H 2 O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn 2+ , which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band (∼ 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe 3+ present in the goethite at g ∼ 2, and in the seeds exist free radicals at g = 2:004, at room temperature

  19. EPR in characterization of seeds paramagnetic species

    Luiz, A.P.C.; Mauro, M.F.F.L.; Portugal, K.O.; Barbana, V.M.; Guedes, C.L.B.; Mauro, E. di; Carneiro, C.E.A.; Zaia, D.A.M.; Prete, C.E.C. [Universidade Estadual de Londrina (UEL), PR (Brazil)

    2011-07-01

    Full text. In Brazil, since 1970s, renewable fuel programs has been developed in order to replace petroleum. Today a program that has been discussed is the bio diesel, which intend to replace diesel fuel, fossil oil, to bio diesel, renewal fuel. As seeds are the basis for production of oil and consequently processed into bio diesel, the goal of this work is to characterize and compare paramagnetic species present in the seeds by Electron Paramagnetic Resonance (EPR). Samples used in this study were seeds of sorghum, barley, corn, peanuts, soy beans, cotton, wheat, oats, mustard, rice, sunflower and turnip. Some paramagnetic species present in soil was also investigated as goethite (FeOOH), hematite (Fe{sub 2}O{sub 3}), magnetite (Fe{sub 3}O{sub 4}), and ferrihydrite (Fe{sub 5}HO{sub 8} {center_dot} 4H{sub 2}O), since, these species present in appreciable quantities in the soil can be present in the seeds and analyzed for comparison. The characterization of these species is essential to understand the EPR seeds spectra. Each sample is placed in a thin quartz tube 4 mm in diameter, and it is inserted into the cavity of the spectrometer at room temperature, at low temperature (77 K) and variable temperature using liquid nitrogen flow and hot flow through a compressor air. It was used as standard Mg O:Mn{sup 2+}, which is also inserted into the cavity. Shortly after the potency is regulated, frequency, amplitude and sweep the field. The spectroscopic analysis by EPR X-band ({approx} 9:5GHz), were performed at the Fluorescence and Electron Paramagnetic Resonance Laboratory, Exact Sciences Center, State University of Londrina, Parana state, Brazil, through an EPR spectrometer JEOL brand (JES-PE-3X). In the EPR spectra, spectroscopic factor or g factor and line width were determined in paramagnetic species. Studies from several seeds with EPR technique detected in all of them presence of same complex of Fe{sup 3+} present in the goethite at g {approx} 2, and in the seeds

  20. Short-term radio variability and parsec-scale structure in A gamma-ray narrow-line Seyfert 1 galaxy 1H 0323+342

    Wajima, Kiyoaki [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Xuhui District, Shanghai 200030 (China); Fujisawa, Kenta [The Research Institute for Time Studies, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8511 (Japan); Hayashida, Masaaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Isobe, Naoki [The Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Ishida, Takafumi [Graduate School of Science and Engineering, Yamaguchi University, 1677-1 Yoshida, Yamaguchi, Yamaguchi 753-8512 (Japan); Yonekura, Yoshinori, E-mail: kwajima@shao.ac.cn [Center for Astronomy, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan)

    2014-02-01

    We made simultaneous single-dish and very long baseline interferometer (VLBI) observations of a narrow-line Seyfert 1 galaxy 1H 323+342, showing gamma-ray activity revealed by Fermi/Large Area Telescope observations. We found significant variation of the total flux density at 8 GHz on the timescale of one month by the single-dish monitoring. The total flux density varied by 5.5% in 32 days, which is comparable to the gamma-ray variability timescale, corresponding to the variability brightness temperature of 7.0 × 10{sup 11} K. The source consists of central and southeastern components on the parsec (pc) scale. Only the flux of the central component decreased in the same way as the total flux density, indicating that the short-term radio variability, and probably the gamma-ray-emitting region, is associated with this component. From the VLBI observations, we obtained brightness temperatures of greater than (5.2 ± 0.3) × 10{sup 10} K and derived an equipartition Doppler factor of greater than 1.7, a variability Doppler factor of 2.2, and an 8 GHz radio power of 10{sup 24.6} W Hz{sup –1}. Combining them, we conclude that acceleration of radio jets and creation of high-energy particles are ongoing in the central engine and that the apparent very radio-loud feature of the source is due to the Doppler boosting effect, resulting in the intrinsic radio loudness being an order of magnitude smaller than the observed values. We also conclude that the pc-scale jet represents recurrent activity from the spectral fitting and the estimated kinematic age of pc- and kpc-scale extended components with different position angles.

  1. Gemini long-slit observations of luminous obscured quasars: Further evidence for an upper limit on the size of the narrow-line region

    Hainline, Kevin N.; Hickox, Ryan C.; Greene, Jenny E.; Myers, Adam D.; Zakamska, Nadia L.; Liu, Guilin; Liu, Xin

    2014-01-01

    We examine the spatial extent of the narrow-line regions (NLRs) of a sample of 30 luminous obscured quasars at 0.4 < z < 0.7 observed with spatially resolved Gemini-N GMOS long-slit spectroscopy. Using the [O III] λ5007 emission feature, we estimate the size of the NLR using a cosmology-independent measurement: the radius where the surface brightness falls to 10 –15 erg s –1 cm –2 arcsec –2 . We then explore the effects of atmospheric seeing on NLR size measurements and conclude that direct measurements of the NLR size from observed profiles are too large by 0.1-0.2 dex on average, as compared to measurements made to best-fit Sérsic or Voigt profiles convolved with the seeing. These data, which span a full order of magnitude in IR luminosity (log (L 8 μm /erg s –1 ) = 44.4-45.4), also provide strong evidence that there is a flattening of the relationship between NLR size and active galactic nucleus luminosity at a seeing-corrected size of ∼7 kpc. The objects in this sample have high luminosities which place them in a previously under-explored portion of the size-luminosity relationship. These results support the existence of a maximal size of the NLR around luminous quasars; beyond this size, there is either not enough gas or the gas is over-ionized and does not produce enough [O III] λ5007 emission.

  2. A paramagnetic nearly isodynamic compact magnetic confinement system

    Cooper, W.A.; Antonietti, J.M.; Todd, T.N.

    2001-01-01

    A coreless compact magnetic confinement system that consists of sets of helical windings and vertical magnetic field coils is investigated. The helical coils produce a small toroidal translation of the magnetic field lines and seed paramagnetism. The force-free component of the toroidal current strongly enhances the paramagnetism such that isodynamic conditions near the plasma centre can be approached. At β 5%, the configuration is stable to local MHD modes. Global MHD modes limit the toroidal current 2πJ to about 60kA for peaked J. Bootstrap-like hollow current profiles generate quasiaxisymmetric systems that require a close fitting conducting shell to satisfy external kink stability. (author)

  3. The Gamma-Ray Emitting Radio-Loud Narrow-Line Seyfert 1 Galaxy PKS 2004-447 II. The Radio View

    Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsaesser, D.; Gehrels, N.; hide

    2016-01-01

    Context. gamma-ray-detected radio-loud narrow-line Seyfert 1 (gamma-NLS1) galaxies constitute a small but interesting sample of the gamma-ray-loud AGN. The radio-loudest gamma-NLS1 known, PKS2004447, is located in the southern hemisphere and is monitored in the radio regime by the multiwavelength monitoring programme TANAMI. Aims. We aim for the first detailed study of the radio morphology and long-term radio spectral evolution of PKS2004447, which are essential for understanding the diversity of the radio properties of gamma-NLS1s. Methods. The TANAMI VLBI monitoring program uses the Australian Long Baseline Array (LBA) and telescopes in Antarctica, Chile, New Zealand, and South Africa to monitor the jets of radio-loud active galaxies in the southern hemisphere. Lower resolution radio flux density measurements at multiple radio frequencies over four years of observations were obtained with the Australia Telescope Compact Array (ATCA). Results. The TANAMI VLBI image at 8.4GHz shows an extended one-sided jet with a dominant compact VLBI core. Its brightness temperature is consistent with equipartition, but it is an order of magnitude below other gamma-NLS1s with the sample value varying over two orders of magnitude. We find a compact morphology with a projected large-scale size 11 kpc and a persistent steep radio spectrum with moderate flux-density variability. Conclusions. PKS2004447 appears to be a unique member of the gamma-NLS1 sample. It exhibits blazar-like features, such as a flat featureless X-ray spectrum and a core-dominated, one-sided parsec-scale jet with indications for relativistic beaming. However, the data also reveal properties atypical for blazars, such as a radio spectrum and large-scale size consistent with compact-steep-spectrum (CSS) objects, which are usually associated with young radio sources. These characteristics are unique among all gamma-NLS1s and extremely rare among gamma-ray-loud AGN.

  4. Model for paramagnetic Fermi systems

    Ainsworth, T.L.; Bedell, K.S.; Brown, G.E.; Quader, K.F.

    1983-01-01

    We develop a mode for paramagnetic Fermi liquids. This model has both direct and induced interactions, the latter including both density-density and current-current response. The direct interactions are chosen to reproduce the Fermi liquid parameters F/sup s/ 0 , F/sup a/ 0 , F/sup s/ 1 and to satify the forward scattering sum rule. The F/sup a/ 1 and F/sup s/,a/sub l/ for l>1 are determined self-consistently by the induced interactions; they are checked aginst experimental determinations. The model is applied in detail to liquid 3 He, using data from spin-echo experiments, sound attenuation, and the velocities of first and zero sound. Consistency with experiments gives definite preferences for values of m. The model is also applied to paramagnetic metals. Arguments are given that this model should provide a basis for calculating effects of magnetic fields

  5. Dating by electron paramagnetic resonance

    Poupeau, G.; Rossi, A.M.

    1984-01-01

    Some natural materials behave like dosimeters in front of the ionizing particle flux coming from environmental radioactivity and the cosmic radiation. This property is used for the dating by Electron Paramagnetic Resonance (EPR). Before presenting the basic principles of the EPR analysis and the dating method which uses such a phenomenous, it is reviewed several types of application currently in course of development. (L.C.) [pt

  6. Exchange coupled pairs of dangling bond spins as a new type of paramagnetic defects in nanodiamonds

    Osipov, V. Yu., E-mail: osipov@mail.ioffe.r [Ioffe Physico-Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg (Russian Federation); Faculty of Electronics, St. Petersburg State Electrotechnical University (LETI), 197376 (Russian Federation); Shames, A.I. [Department of Physics, Ben-Gurion University of the Negev, 84105 Be' er-Sheva (Israel); Vul' , A. Ya. [Ioffe Physico-Technical Institute, Polytechnicheskaya 26, 194021 St. Petersburg (Russian Federation)

    2009-12-15

    EPR in detonation nanodiamonds (DND) reveals two different signals associated with intrinsic carbon inherited paramagnetic defects. Main carbon inherited EPR signal is narrow intensive Lorentzian-like singlet with g=2.0028 and spin concentration N{sub s}=(6-7)x10{sup 19} spin/g that yields on average 13-15 spins per each DND particle. Additional chemical treatment of DND powder allows practically complete removal of trace amounts of transition metal impurities that reveals a new doublet EPR signal consisting of two relatively narrow lines within the half-field region (gapprox4) separated by a distance of 10.4 mT. The intensity of the doublet signal is five orders of magnitude lower than that of the main singlet signal. The former signal has been observed in a wide variety of DND samples disregarding of the impurity level reached and thus may be attributed to some intrinsic defects in DND particles. Such half-field EPR signals correspond to 'forbidden' DELTAM{sub s}=2 transitions within thermally populated triplet (S=1) levels observed in polycrystalline samples containing exchange dimers-antiferromagnetically coupled spin pairs. Estimates suggest that the concentration of such defects is about one dimer per hundreds DND particles.

  7. Application of Numerical Analysis of the Shape of Electron Paramagnetic Resonance Spectra for Determination of the Number of Different Groups of Radicals in the Burn Wounds

    Paweł Olczyk

    2017-01-01

    Full Text Available Background. The evidence exists that radicals are crucial agents necessary for the wound regeneration helping to enhance the repair process. Materials and methods. The lineshape of the electron paramagnetic resonance (EPR spectra of the burn wounds measured with the low microwave power (2.2 mW was numerically analyzed. The experimental spectra were fitted by the sum of two and three lines. Results. The number of the lines in the EPR spectrum corresponded to the number of different groups of radicals in the natural samples after thermal treatment. The component lines were described by Gaussian and Lorentzian functions. The spectra of the burn wounds were superposition of three lines different in shape and in linewidths. The best fitting was obtained for the sum of broad Gaussian, broad Lorentzian, and narrow Lorentzian lines. Dipolar interactions between the unpaired electrons widened the broad Gaussian and broad Lorentzian lines. Radicals with the narrow Lorentzian lines existed mainly in the tested samples. Conclusions. The spectral shape analysis may be proposed as a useful method for determining the number of different groups of radicals in the burn wounds.

  8. Itinerant ferromagnetism in the narrow band limit

    Liu, S H

    2000-01-01

    It is shown that in the narrow band, strong interaction limit the paramagnetic state of an itinerant ferromagnet is described by the disordered local moment state. As a result, the Curie temperature is orders of magnitude lower than what is expected from the large exchange splitting of the spin bands. An approximate analysis has also been carried out for the partially ordered state, and the result explains the temperature evolvement of the magnetic contributions to the resistivity and low-energy optical conductivity of CrO sub 2.

  9. Paramagnetism in ion-implanted oxides

    Mølholt, Torben Esmann; Gíslason, Hafliði Pétur; Ólafsson, Sveinn

    This thesis describes the investigation on para-magnetism in dilute ion-implanted single-crystal oxide samples studied by on- and off-line $^{57}$Fe emission Mössbauer spectroscopy. The ion-implantation of the radioactive isotopes ( $^{57}$Mn and $^{57}$Co) was performed at the ISOLDE facility at CERN in Geneva, Switzerland. The off-line measurements were performed at Aarhus University, Denmark. Mössbauer spectroscopy is a unique method, giving simultaneously local information on valence/spin state of the $^{57}$Fe probe atoms, site symmetry and magnetic properties on an atomic scale. The utilisation of emission Mössbauer spectroscopy opens up many new possibilities compared with traditional transmission Mössbauer spectroscopy. Among them is the possibility of working with a low concentration below 10$^{-4}$ –10$^{-3}$ at.%, where the implanted Mössbauer $^{57}$Fe probes are truly dilute impurities exclusively interacting with their nearest neighbours and therefore the possibility of crea...

  10. Electron paramagnetic resonance (EPR) biodosimetry

    Desrosiers, Marc; Schauer, David A.

    2001-01-01

    Radiation-induced electron paramagnetic resonance (EPR) signals were first reported by Gordy et al. [Proc. Natl. Acad. Sci. USA 41 (1955) 983]. The application of EPR spectroscopy to ionizing radiation dosimetry was later proposed by Brady et al. [Health Phys. 15 (1968) 43]. Since that time EPR dosimetry has been applied to accident and epidemiologic dose reconstruction, radiation therapy, food irradiation, quality assurance programs and archaeological dating. Materials that have been studied include bone, tooth enamel, alanine and quartz. This review paper presents the fundamentals and applications of EPR biodosimetry. Detailed information regarding sample collection and preparation, EPR measurements, dose reconstruction, and data analysis and interpretation will be reviewed for tooth enamel. Examples of EPR biodosimetry application in accidental overexposures, radiopharmaceutical dose assessment and retrospective epidemiologic studies will also be presented

  11. Paramagnetic pharmaceuticals for functional studies

    Hall, L.D.; Hogan, P.G.

    1987-01-01

    It has been suggested that limitations of the Magnetic Resonance Imaging (MRI) method may be minimised by the use of ''image contrast'' agents. These are exogenous chemicals administered to the patient which, by influencing the magnetic resonance properties of the water in the region of the pathology, serve to heighten the contrast between that tissue and its surroundings. At present the most widely used agent is gadolinium-DTPA (Gd-DTPA). This appears to have many desirable features and its development provides a textbook example for the early stages of any future development. All compounds used so far can be subdivided into one of the following categories: Paramagnetic metal species; Ferromagnetic metal species; Stable free radicals; Oxygen carriers; Susceptibility agents; and Density substitution agents. The authors summarise briefly these chemical substances and their reported uses

  12. Study of Unwanted Emissions in the CENELEC-A Band Generated by Distributed Energy Resources and Their Influence over Narrow Band Power Line Communications

    Noelia Uribe-Pérez

    2016-11-01

    Full Text Available Distributed Energy Resources might have a severe influence on Power Line Communications, as they can generate interfering signals and high frequency emissions or supraharmonics that may cause loss of metering and control data. In this paper, the influence of various energy resources on Narrowband Power Line Communications is described and analyzed through several test measurements performed in a real microgrid. Accordingly, the paper describes the effects on smart metering communications through the Medium Access Control (MAC layer analysis. Results show that the switching frequency of inverters and the presence of battery chargers are remarkable sources of disturbance in low voltage distribution networks. In this sense, the results presented can contribute to efforts towards standardization and normative of emissions at higher frequencies higher, such as CENELEC EN 50160 and IEC/TS 62749.

  13. Magnetic resonance studies of isotopically labeled paramagnetic proteins: (2FE-2S) ferredoxins

    Cheng, H.; Xia, B.; Chae, Y.K.; Westler, W.M.; Markley, J.L. [Univ. of Wisconsin, Madison, WI (United States)

    1994-12-01

    Recent developments in NMR spectroscopy, especially multidimensional, multinuclear NMR techniques, have made NMR the most versatile tool available for studying protein structure and function in solution. Unlike diamagnetic proteins, paramagnetic proteins contain centers with unpaired electrons. These unpaired electrons interact with magnetic nuclei either through chemical bonds by a contact mechanism or through space by a pseudocontact mechanism. Such interactions make the acquisition and analysis of NMR spectra of paramagnetic proteins more challenging than those of diamagnetic proteins. Some NMR signals from paramagnetic proteins are shifted outside the chemical shift region characteristic of diamagnetic proteins; these {open_quotes}hyperfine-shifted{close_quotes} resonances originate from nuclei that interact with unpaired electrons from the paramagnetic center. The large chemical shift dispersion in spectra of paramagnetic proteins makes it difficult to excite the entire spectral window and leads to distortions in the baseline. Interactions with paramagnetic centers shorten T{sub 1} and T{sub 2} relaxation times of nuclei; the consequences are line broadening and lower spectral sensitivity. Scalar (through bond) and dipolar (through space) interactions between pairs of nuclei are what give rise to crosspeak signals in multi-dimensional NMR spectra of small diamagnetic proteins. When such interactions involve a nucleus that is strongly relaxed by interaction with a paramagnetic center, specialized methods may be needed for its detection or it may be completely undetectable by present nD NMR methods.

  14. Contribution to the study of electron paramagnetic resonance and relaxation

    Theobald, Jean-Gerard

    1962-01-01

    This research thesis reports an experimental work which comprises the development of a very practical and very sensitive electron paramagnetic resonance spectrometer, and the use of this equipment for the study of irradiated substances and carbons. By studying electronic resonance signals by fast modulation of the magnetic field, the author studied phenomena of quick passage in electronic resonance, and showed that the study of these phenomena requires observation systems with a particularly large bandwidth. He reports the measurement of the line width of packs of spins of inhomogeneous lines by two different methods [fr

  15. THE RISE OF AN IONIZED WIND IN THE NARROW-LINE SEYFERT 1 GALAXY Mrk 335 OBSERVED BY XMM-NEWTON AND HST

    Longinotti, A. L.; Krongold, Y.; Kriss, G. A.; Ely, J.; Gallo, L.; Grupe, D.; Komossa, S.; Mathur, S.; Pradhan, A.

    2013-01-01

    We present the discovery of an outflowing ionized wind in the Seyfert 1 galaxy Mrk 335. Despite having been extensively observed by most of the largest X-ray observatories in the last decade, this bright source was not known to host warm absorber gas until recent XMM-Newton observations in combination with a long-term Swift monitoring program have shown extreme flux and spectral variability. High-resolution spectra obtained by the XMM-Newton Reflection Grating Spectrometer (RGS) detector reveal that the wind consists of three distinct ionization components, all outflowing at a velocity of ∼5000 km s –1 . This wind is clearly revealed when the source is observed at an intermediate flux state (2-5 × 10 –12 erg cm –2 s –1 ). The analysis of multi-epoch RGS spectra allowed us to compare the absorber properties at three very different flux states of the source. No correlation between the warm absorber variability and the X-ray flux has been determined. The two higher ionization components of the gas (log ξ ∼ 2.3 and 3.3) may be consistent with photoionization equilibrium, but we can exclude this for the only ionization component that is consistently present in all flux states (log ξ ∼ 1.8). We have included archival, non-simultaneous UV data from Hubble Space Telescope (FOS, STIS, COS) with the aim of searching for any signature of absorption in this source that so far was known for being absorption-free in the UV band. In the Cosmic Origins Spectrograph (COS) spectra obtained a few months after the X-ray observations, we found broad absorption in C IV lines intrinsic to the active galactic nucleus and blueshifted by a velocity roughly comparable to the X-ray outflow. The global behavior of the gas in both bands can be explained by variation of the covering factor and/or column density, possibly due to transverse motion of absorbing clouds moving out of the line of sight at broad line region scale.

  16. Electromagnetic activity of a pulsating paramagnetic neutron star

    Bastrukov, S.I.; Podgainy, D.V.; Yang, J.; Weber, F.

    2002-01-01

    The fact that neutron star matter possesses the capability of maintaining a highly intense magnetic field has been and still is among the most debatable issues in pulsar astrophysics. Over the years, there were several independent suggestions that the dominant source of pulsar magnetism is either the field-induced or the spontaneous magnetic polarization of the baryon material. The Pauli paramagnetism of degenerate neutron matter is one of the plausible and comprehensive mechanisms of the magnetic ordering of neutron magnetic moments, promoted by a seed magnetic field inherited by the neutron star from a massive progenitor and amplified by its implosive contraction due to the magnetic flux conservation. Adhering to this attitude and based on the equations of magnetoelastic dynamics underlying continuum mechanics of single-axis magnetic insulators, we investigate electrodynamics of a paramagnetic neutron star undergoing nonradial pulsations. We show that the suggested approach regains a recent finding of Akhiezer et al. that the spin-polarized neutron matter can transmit perturbations by low-frequency transverse magnetoelastic waves. We found that nonradial torsional magnetoelastic pulsations of a paramagnetic neutron star can serve as a powerful generator of a highly intense electric field producing the magnetospheric polarization charge whose acceleration along the open magnetic field lines leads to the synchrotron and curvature radiation. Analytic and numerical estimates for periods of nonradial torsional magnetoelastic modes are presented and are followed by a discussion of their possible manifestation in currently monitored activity of pulsars and magnetars

  17. Decay of paramagnetic centers in polyacetylene

    Hola, O.

    1994-01-01

    The time dependences of the relative concentration of spins in irradiated and unirradiated samples of polyacetylene have been studied. Similar courses of the decay of paramagnetic centers were observed in both types of samples. (author) 6 refs.; 1 fig

  18. Symmetric Imidazolium-Based Paramagnetic Ionic Liquids

    2017-11-29

    Charts N/A Unclassified Unclassified Unclassified SAR 14 Kamran Ghiassi N/A 1 Symmetric Imidazolium-Based Paramagnetic Ionic Liquids Kevin T. Greeson...NUMBER (Include area code) 29 November 2017 Briefing Charts 01 November 2017 - 30 November 2017 Symmetric Imidazolium-Based Paramagnetic Ionic ... Liquids K. Greeson, K. Ghiassi, J. Alston, N. Redeker, J. Marcischak, L. Gilmore, A. Guenthner Air Force Research Laboratory (AFMC) AFRL/RQRP 9 Antares

  19. On kinetics of paramagnetic radiation defects accumulation in beryllium ceramics; O kinetike nakopleniya paramagnitnykh radiatsionnykh defektov v berillievykh keramikakh

    Polyakov, A I; Ryabikin, Yu A; Zashkvara, O V; Bitenbaev, M I; Petykhov, Yu V [Fiziko-Tekhnicheskij Inst., Almaty (Kazakhstan); Inst. Atomnoj Ehnergii, Kurchatov (Kazakhstan)

    1999-07-01

    Results of paramagnetic radiation defects concentration dependence study in beryllium ceramics from gamma-irradiation dose ({sup 60}Co) within interval 0-100 Mrem are cited. Obtained dose dependence has form of accumulation curve with saturation typical of for majority of solids (crystals, different polymers, organic substances and others) , in which under irradiation occur not only formation of paramagnetic radiation defects, but its destruction due to recombination and interaction with radiation fields. Analysis of accumulation curve by the method of distant asymptotics allows to determine that observed in gamma-irradiated beryllium ceramics double line of electron spin resonance is forming of two types of paramagnetic radiation defects. It was defined, that sum paramagnetic characteristics of beryllium ceramics within 1-100 Mrad gamma- irradiation dose field change insignificantly and define from first type of paramagnetic radiation defects.

  20. Modeling the Broad-Band Emission from the Gamma-Ray Emitting Narrow-Line Seyfert-1 Galaxies 1H 0323+342 and B2 0954+25A

    Arrieta-Lobo, Maialen; Boisson, Catherine; Zech, Andreas

    2017-01-01

    Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert 1 (NLSy1) galaxies has put them on the spotlight as a new class of gamma-ray emitting AGN. In this respect, gamma-ray emitting NLSy1s seem to be situated between blazars (dominated by non-thermal emission) and Seyferts (accretion disc dominated). In this work, we model the Spectral Energy Distribution (SED) of two gamma-loud NLSy1s, 1H 0323+342 and B2 0954+25A, during quiescent and flaring episodes via a multi-component radiative model that features a relativistic jet and external photon fields from the torus, disc, corona and Broad Line Region (BLR). We find that the interpretation of the high-energy emission of jetted NLSy1s requires taking into account Inverse Compton emission from particles in the relativistic jet that interact with external photon fields. Minimal changes are applied to the model parameters to transition from average to flaring states. In this scenario, the observed variability is explained mainly by means of changes in the jet density and Doppler factor.

  1. Modeling the Broad-Band Emission from the Gamma-Ray Emitting Narrow-Line Seyfert-1 Galaxies 1H 0323+342 and B2 0954+25A

    Arrieta-Lobo, Maialen; Boisson, Catherine; Zech, Andreas, E-mail: maialen.arrieta@obspm.fr [Laboratoire Univers et Theories, Observatoire de Paris, CNRS, Université Paris-Diderot, PSL Research University, Meudon (France)

    2017-12-08

    Prior to the Fermi-LAT era, only two classes of Active Galactic Nuclei (AGN) were thought to harbor relativistic jets that radiate up to gamma-ray energies: blazars and radio galaxies. The detection of variable gamma-ray emission from Narrow Line Seyfert 1 (NLSy1) galaxies has put them on the spotlight as a new class of gamma-ray emitting AGN. In this respect, gamma-ray emitting NLSy1s seem to be situated between blazars (dominated by non-thermal emission) and Seyferts (accretion disc dominated). In this work, we model the Spectral Energy Distribution (SED) of two gamma-loud NLSy1s, 1H 0323+342 and B2 0954+25A, during quiescent and flaring episodes via a multi-component radiative model that features a relativistic jet and external photon fields from the torus, disc, corona and Broad Line Region (BLR). We find that the interpretation of the high-energy emission of jetted NLSy1s requires taking into account Inverse Compton emission from particles in the relativistic jet that interact with external photon fields. Minimal changes are applied to the model parameters to transition from average to flaring states. In this scenario, the observed variability is explained mainly by means of changes in the jet density and Doppler factor.

  2. Paramagnetic resonance and susceptibility of ilmenite, FeTiO3 crystal

    Mcdonald, P. F.; Parasiris, A.; Pandey, R. K.; Gries, B. L.; Kirk, W. P.

    1991-01-01

    Large high-purity single crystals of FeTiO3 with ilmenite structure have been grown from a stoichiometric melt of Fe2O3 and TiO2 under an inert atmosphere using the modified Czochralski technique. Susceptibility and X-band paramagnetic resonance studies have been performed. Susceptibility measurements indicate a Neel temperature of about 59 K. The paramagnetic resonance spectrum for magnetic field perpendicular to the crystal c axis consists of a portion of a single, very intense approximately Lorentzian absorption line with its peak at about 600 G and half width at half maximum almost 1200 G. The absorption extends to zero magnetic field. For magnetic field approximately parallel to the c axis, the paramagnetic absorption is much smaller and may be considered a superposition of two approximately Lorentzian line shapes. The magnetic resonance measurements indicate a weak temperature dependence and large angular anisotropy.

  3. Narrow-Line Seyfert 1 Galaxies

    Komossa, S.

    2007-01-01

    Presento una revisión breve de las propiedades conocidas de las galaxias Seyfert 1 con líneas angostas (NLS1) en todo el espectro electromagnético y de los modelos propuestos para explicarlas. Sus propiedades de continuo y de emisión de líneas manifiestan una forma extrema de la actividad Seyfert. Las galaxias NLS1 en sí pueden ofrecer pistas importantes para discernir los parámetros que impulsan la actividad nuclear. Sus tasas de acreción altas y cercanas a la tasa de Eddington proveen...

  4. A narrow pH range supports butanol, hexanol, and octanol production from syngas in a continuous co-culture of Clostridium ljungdahlii and Clostridium kluyveri with in-line product extraction

    Hanno Richter

    2016-11-01

    Full Text Available Carboxydotrophic bacteria (CTB have received attention due to their ability to synthesize commodity chemicals from producer gas and synthesis gas (syngas. CTB have an important advantage of a high product selectivity compared to chemical catalysts. However, the product spectrum of wild-type CTB is narrow. Our objective was to investigate whether a strategy of combining two wild-type bacterial strains into a single, continuously fed bioprocessing step would be promising to broaden the product spectrum. Here, we have operated a syngas-fermentation process with Clostridium ljungdahlii and Clostridium kluyveri with in-line product extraction through gas stripping and product condensing within the syngas recirculation line. The main products from C. ljungdahlii fermentation at a pH of 6.0 were ethanol and acetate at net volumetric production rates of 65.5 and 431 mmol C•L-1•d-1, respectively. An estimated 2/3 of total ethanol produced was utilized by C. kluyveri to chain elongate with the reverse β-oxidation pathway, resulting in n-butyrate and n-caproate at net rates of 129 and 70 mmol C•L-1•d-1, respectively. C. ljungdahlii likely reduced the produced carboxylates to their corresponding alcohols with the reductive power from syngas. This resulted in the longer-chain alcohols n-butanol, n-hexanol, and n-octanol at net volumetric production rates of 39.2, 31.7, and 0.045 mmol C•L-1•d-1, respectively. The continuous production of the longer-chain alcohols occurred only within a narrow pH spectrum of 5.7-6.4 due to the pH discrepancy between the two strains. Regardless whether other wild-type strains could overcome this pH discrepancy, the specificity (mol carbon in product per mol carbon in all other liquid products for each longer-chain alcohol may never be high in a single bioprocessing step. This, because two bioprocesses compete for intermediates (i.e., carboxylates: 1 chain elongation; and 2 biological reduction. This innate

  5. Narrow dibaryon resonances

    Kajdalov, A.B.

    1986-01-01

    Experimental data on np interactions indicating to existence of narrow resonances in pp-system are discussed. Possible theoretical interpretations of these resonances are given. Experimental characteristics of the dibaryon resonances with isospin I=2 are considered

  6. Buckling of paramagnetic chains in soft gels

    Huang, Shilin; Pessot, Giorgio; Cremer, Peet; Weeber, Rudolf; Holm, Christian; Nowak, Johannes; Odenbach, Stefan; Menzel, Andreas M.; Auernhammer, Günter K.

    We study the magneto-elastic coupling behavior of paramagnetic chains in soft polymer gels exposed to external magnetic fields. To this end, a laser scanning confocal microscope is used to observe the morphology of the paramagnetic chains together with the deformation field of the surrounding gel network. The paramagnetic chains in soft polymer gels show rich morphological shape changes under oblique magnetic fields, in particular a pronounced buckling deformation. The details of the resulting morphological shapes depend on the length of the chain, the strength of the external magnetic field, and the modulus of the gel. Based on the observation that the magnetic chains are strongly coupled to the surrounding polymer network, a simplified model is developed to describe their buckling behavior. A coarse-grained molecular dynamics simulation model featuring an increased matrix stiffness on the surfaces of the particles leads to morphologies in agreement with the experimentally observed buckling effects.

  7. Paramagnetism: an alternative view. Pt. 1

    Oudet, X.

    1991-01-01

    A new calculation of the paramagnetic susceptibility χ is proposed on the basis of the statistical distribution of the thermal energy using the mean value U of this energy as statistical variable. This allows us to replace the molecular field by an equivalent energy barrier that the paramagnetic moment of an atom has to cross to contribute to χ. The variation of χ with U, or T as well, shows a maximum when there is no magnetic order. The asymptotic character of the Curie-Weiss law appears in close connection with that of the Dulong and Petit law. (orig.)

  8. Electron paramagnetic resonance study of Ce doped partially stabilized ZrO2 crystals

    Mikhail А. Borik

    2017-09-01

    Full Text Available ZrO2 (PSZ solid solutions crystals stabilized with yttrium and cerium oxides have been studied using electron paramagnetic resonance (EPR in the X and Q ranges. Zr3+ have been observed centers in the as-annealed ZrO2 crystals stabilized only by yttrium oxide (2.8 mol% Y2O3. Another type of paramagnetic-O-centers appear as a result of CeO2 addition to ZrO2 crystals along with yttrium oxide. To estimate the concentration of Ce3+ ions in PZS crystals, we recorded the EPR spectra in the presence of a reference at 7 K. Paramagnetic Ce3+ ions have been identified and their relative amount in the PSZ crystals before and after high-temperature heat treatment has been assessed. Annealing in air leads decreases the concentration of Ce3+ ions for all the test compositions and changes the color of the crystals from red to white. After annealing of the sample 2.0Y0.8Ce3Zr, the amount of paramagnetic Ce3+ ions decreased approximately twofold. Paramagnetic centers from Ce3+ have not been detected in the specimen with a low cerium content of 0.1 mol% after annealing which indicates the complete transition of Ce3+ to the Ce4+ state. We show that the forming cerium paramagnetic centers are bound by strong exchange interactions. No angular dependence of the EPR lines of the paramagnetic Ce3+ cations on the applied external magnetic field has been observed. Probable origin of the absence of angular dependence is that the impurity rare-earth ions are located close to one another, forming impurity clusters with an effective spin of Seff=1/2.

  9. Susceptibility cancellation of a microcoil wound with a paramagnetic-liquid-filled copper capillary

    Takeda, Kazuyuki; Takasaki, Tomoya; Takegoshi, K.

    2015-09-01

    Even though microcoils improve the sensitivity of NMR measurement of tiny samples, magnetic-field inhomogeneity due to the bulk susceptibility effect of the coil material can cause serious resonance-line broadening. Here, we propose to fabricate the microcoil using a thin, hollow copper capillary instead of a wire and fill paramagnetic liquid inside the capillary, so as to cancel the diamagnetic contribution of the copper. Susceptibility cancellation is demonstrated using aqueous solution of NiSO4. In addition, the paramagnetic liquid serves as coolant when it is circulated through the copper capillary, effectively transferring the heat generated by radiofrequency pulses.

  10. LINES

    Minas Bakalchev

    2015-10-01

    Full Text Available The perception of elements in a system often creates their interdependence, interconditionality, and suppression. The lines from a basic geometrical element have become the model of a reductive world based on isolation according to certain criteria such as function, structure, and social organization. Their traces are experienced in the contemporary world as fragments or ruins of a system of domination of an assumed hierarchical unity. How can one release oneself from such dependence or determinism? How can the lines become less “systematic” and forms more autonomous, and less reductive? How is a form released from modernistic determinism on the new controversial ground? How can these elements or forms of representation become forms of action in the present complex world? In this paper, the meaning of lines through the ideas of Le Corbusier, Leonidov, Picasso, and Hitchcock is presented. Spatial research was made through a series of examples arising from the projects of the architectural studio “Residential Transformations”, which was a backbone for mapping the possibilities ranging from playfulness to exactness, as tactics of transformation in the different contexts of the contemporary world.

  11. Theoretical study of the electron paramagnetic resonance ...

    conveniently investigated by means of electron paramagnetic resonance (EPR). In ... ion Ir2+ can experience the Jahn–Teller effect by means of vibration interaction, ... Similarly, k. (and k ) are the orbital reduction factors arising from the anisotropic interactions of the orbital angular momentum operator. From the cluster ...

  12. Recent results on some columnar paramagnetic metallomesogens

    A broader view on some physical properties of columnar paramagnetic ... was evident by X-ray crystal structure determination in the solid state on a homologous ... leading to interfacial polarization as described for other LC materials before [9]. ... dodecyloxy tail on the phenyl rings) was described to exhibit a Colho phase ...

  13. Microassembly using a Cluster of Paramagnetic Microparticles

    Khalil, I.S.M.; Brink, F.V; Sardan Sukas, Ö.; Misra, Sarthak

    2013-01-01

    We use a cluster of paramagnetic microparticles to carry out a wireless two-dimensional microassembly operation. A magnetic-based manipulation system is used to control the motion of the cluster under the influence of the applied magnetic fields. Wireless motion control of the cluster is implemented

  14. Depolarization of diffusing spins by paramagnetic impurities

    Schillaci, M.E.; Hutson, R.L.; Heffner, R.H.; Leon, M.; Dodds, S.A.; Estle, T.L.

    1981-01-01

    We study the depolarization of diffusing spins (muons) interacting with dilute paramagnetic impurities in a solid using a simple computational model which properly treats the muon motion and preserves correct muon-impurity distances. Long-range (dipolar) and nearest-neighbor (contact) interactions are treated together. Diffusion parameters are deduced and model comparisons made for AuGd (300 ppm). (orig.)

  15. Dual excitation acoustic paramagnetic logging tool

    Vail, III, William B. (Bothell, WA)

    1989-01-01

    New methods and apparatus are disclosed which allow measurement of the presence of oil and water in gelogical formations using a new physical effect called the Acoustic Paramagnetic Logging Effect (APLE). The presence of petroleum in formation causes a slight increase in the earth's magnetic field in the vicinity of the reservoir. This is the phenomena of paramagnetism. Application of an acoustic source to a geological formation at the Larmor frequency of the nucleous present causes the paramagnetism of the formation to disappear. This results in a decrease in the earth's magnetic field in the vicinity of the oil bearing formation. Repetitively frequency sweeping the acoustic source through the Larmor frequency of the nucleons present (approx. 2 kHz) causes an amplitude modulation of the earth's magnetic field which is a consequence of the APLE. The amplitude modulation of the earth's magnetic field is measured with an induction coil gradiometer and provides a direct measure of the amount of oil and water in the excitation zone of the formation. The phase of the signal is used to infer the longitudinal relaxation times of the fluids present, which results in the ability in general to separate oil and water and to measure the viscosity of the oil present. Such measurements may be preformed in open boreholes and in cased well bores. The Dual Excitation Acoustic Paramagnetic Logging Tool employing two acoustic sources is also described.

  16. A superheterodyne spectrometer for electronic paramagnetic. Resonance

    Laffon, J.L.

    1963-12-01

    After a few generalities about electron paramagnetic resonance, a consideration of different experimental techniques authorises the choice of a particular type of apparatus. An EPR superheterodyne spectrometer built in the laboratory and having a novel circuit is described in detail. With this apparatus, many experimental results have been obtained and some of these are described as example. (author) [fr

  17. Jihadism, Narrow and Wide

    Sedgwick, Mark

    2015-01-01

    The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

  18. An EPR study on tea: Identification of paramagnetic species, effect of heat and sweeteners

    Bıyık, Recep; Tapramaz, Recep

    2009-10-01

    Tea ( Camellia Sinensis) is the most widely consumed beverage in the world, and is known to be having therapeutic, antioxidant and nutritional effects. Electron paramagnetic resonance (EPR) spectral studies made on the tea cultivated along the shore of Black Sea, Turkey, show Mn 2+ and Fe 3+ centers in green tea leaves and in black tea extract. Dry black tea flakes and dry extract show additional sharp line attributed to semiquinone radical. The origins of the paramagnetic species in black tea are defined and discussed. Effect of humidity and heat are investigated. It is observed that dry extract of black tea melts at 100 °C and the semiquinone radical lives up to 140 °C while Mn 2+ sextet disappears just above 100 °C in tea extract. Natural and synthetics sweeteners have different effects on the paramagnetic centers. White sugar (sucrose) quenches the Mn 2+ and semiquinone lines in black tea EPR spectrum, and glucose, fructose, lactose and maltose quench Fe 3+ line while synthetic sweeteners acesulfam potassium, aspartame and sodium saccharine do not have any effect on paramagnetic species in tea.

  19. Electron paramagnetic resonance investigations of carbon-doped β rhombohedral boron

    Gercke, U.; Siems, C.-D.

    1979-01-01

    Electron paramagnetic resonance (EPR) measurements at 9 and 35 GHz on polycrystalline β rhombohedral boron with various carbon contents resulted in partly resolved absorption spectra. At 300 K the spin density ratio of two lines (called D and E) showed a linear increase with the carbon content. This ratio is temperature dependent. The lines D and E are photo-EPR active with different quantum efficiencies at various temperatures. (Auth.)

  20. The application of electron paramagnetic resonance in biomedical research

    Qu Ximei; Wang Liqin; Zhang Wenyi; Liu Zhongchao; Cui Songye; Feng Xin; Jiaoling

    2013-01-01

    Electron paramagnetic resonance technique has been found more than half a century, for free radicals detection application, it has been applied to various research studies, and promotes the development of the biomedicine. This article summarized the various free radicals measurement by the electron paramagnetic resonance in biology tissue, and the application of the spin labeling and electron paramagnetic resonance imaging technology in biomedicine. (authors)

  1. Data acquisition system for electronic paramagnetic resonance spectrophotometer

    Pena Eguiluz, R.

    1992-01-01

    In the Atomic and Molecular Physics Laboratory at the Physics Department of the Instituto Nacional de Investigaciones Nucleares (ININ), there is in operation an electronic paramagnetic resonance spectrometer (EPR). This equipment is utilized for determine, the distribution of the absorbed energy intensity for a sample of paramagnetic substance by means of the study and analysis of its emission lines spectrum. The useful information is provided as a graphic result showing the spectrum corresponding to the analyzed sample. In similar devices like this, the researchers problem, trying to get the important information, is a hard and imprecise work, thus, this process of find the ordinate magnitudes of a approximately two hundred points, equal spaced in the spectrum, is carried out completely by hand. After this, the information is captured and processed in a personal computer. As a solution for this problem, an interface in both aspects, hardware and software adaptable to a personal computer, was designed and constructed. This interface is able to: a) To get and digitized the analogical signal, that represents the corresponding spectrum curve. b) It stores the digitized information in files and c) It displays in graphic mode the stored data, and then these are normalized in order to be transferred to a statistics and analytical software packets (Author)

  2. Correlates of Narrow Bracketing

    Koch, Alexander; Nafziger, Julia

    We examine whether different phenomena of narrow bracketing can be traced back to some common characteristic and whether and how different phenomena are related. We find that making dominated lottery choices or ignoring the endowment when making risky choices are related phenomena and are both as...

  3. On the paramagnetism of spin in the classical limit

    Hogreve, H.

    1985-12-01

    We consider particles with spin 1/2 in external electromagnetic fields. Although in many quantum mechanical situations they show a paramagnetic behaviour, within non-relativistic quantum theory a universal paramagnetic influence of spin fails to be true in general. Here we investigate the paramagnetism of spin in the framework of a classical theory. Applying previous results for the classical limit slash-h→O we obtain a classical expression corresponding to the quantum partition function of Hamiltonians with spin variables. For this classical partition function simple estimates lead to a paramagnetic inequality which demonstrates that indeed in the classical limit the spin shows a general paramagnetic behaviour. (author)

  4. Study of actinide paramagnetism in solution

    Autillo, Matthieu

    2015-01-01

    The physiochemical properties of actinide (An) solutions are still difficult to explain, particularly the behavioral differences between An(III) and Ln(III). The study of actinide paramagnetic behavior may be a 'simple' method to analyze the electronic properties of actinide elements and to obtain information on the ligand-actinide interaction. The objective of this PhD thesis is to understand the paramagnetic properties of these elements by magnetic susceptibility measurements and chemical shift studies. Studies on actinide electronic properties at various oxidation states in solution were carried out by magnetic susceptibility measurements in solution according to the Evans method. Unlike Ln(III) elements, there is no specific theory describing the magnetic properties of these ions in solution. To obtain accurate data, the influence of experimental measurement technique and radioactivity of these elements was analyzed. Then, to describe the electronic structure of their low energy states, the experimental results were complemented with quantum chemical calculations from which the influence of the ligand field was studied. Finally, these interpretations were applied to better understand the variations in the magnetic properties of actinide cations in chloride and nitrate media. Information about ligand-actinide interactions may be determined from an NMR chemical shift study of actinide complexes. Indeed, modifications induced by a paramagnetic complex can be separated into two components. The first component, a Fermi contact contribution (δ_c) is related to the degree of covalency in coordination bonds with the actinide ions and the second, a dipolar contribution (δ_p_c) is related to the structure of the complex. The paramagnetic induced shift can be used only if we can isolate these two terms. To achieve this study on actinide elements, we chose to work with the complexes of dipicolinic acid (DPA). Firstly, to characterize the geometrical parameters, a

  5. Paramagnetic form factors from itinerant electron theory

    Cooke, J.F.; Liu, S.H.; Liu, A.J.

    1985-01-01

    Elastic neutron scattering experiments performed over the past two decades have provided accurate information about the magnetic form factors of paramagnetic transition metals. These measurements have traditionally been analyzed in terms of an atomic-like theory. There are, however, some cases where this procedure does not work, and there remains the overall conceptual problem of using an atomistic theory for systems where the unpaired-spin electrons are itinerant. We have recently developed computer codes for efficiently evaluating the induced magnetic form factors of fcc and bcc itinerant electron paramagnets. Results for the orbital and spin contributions have been obtained for Cr, Nb, V, Mo, Pd, and Rh based on local density bands. By using calculated spin enhancement parameters, we find reasonable agreement between theory and neutron form factor data. In addition, these zero parameter calculations yield predictions for the bulk susceptibility on an absolute scale which are in reasonable agreement with experiment in all treated cases except palladium

  6. Role of spinning electrons in paramagnetic phenomena

    Bose, D.M.

    1986-06-01

    An attempt is made to explain paramagnetic phenomena without assuming the orientation of a molecule or ion in a magnetic field. Only the spin angular momentum is assumed to be responsible. A derivative of the Gurie-Langevin law and the magnetic moments of ions are given as a function of the number of electrons in an inner, incomplete shell. An explanation of Gerlach's experiments with iron and nickel vapors is attempted. An explanation of magnetomechanical experiments with ferromagnetic elements is given

  7. Multifrequency Electron Paramagnetic Resonance Theory and Applications

    Misra, Sushil K

    2011-01-01

    Filling the gap for a systematic, authoritative, and up-to-date review of this cutting-edge technique, this book covers both low and high frequency EPR, emphasizing the importance of adopting the multifrequency approach to study paramagnetic systems in full detail by using the EPR method. In so doing, it discusses not only the underlying theory and applications, but also all recent advances -- with a final section devoted to future perspectives.

  8. Electron paramagnetic resonance (EPR) in characterization of rocks and minerals

    Valezi, D.F.; Mauro, E. di [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Lab. de Fluorescencia e Ressonaancia Paramagnetica Eletronica (LAFLURPE); Zaia, D.A.M.; Carneiro, C.E.A. [Universidade Estadual de Londrina (UEL), PR (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Costa, A.C.S. da [Universidade Estadual de Maringa (UEM), PR (Brazil). Centro de Ciencias Agrarias. Dept. de Agronomia

    2011-07-01

    Full text. his work is based on the study of several stones and minerals from the Parana state, Brazil. They were analyzed by the Electron Paramagnetic Resonance (EPR) technique. The measurements were made on a spectrometer JEOL (JES-PE-3X), operating on X-band and at room temperature, with the exception of the mineral Goethite, which was measured with temperature variation. In all the samples were determined spectroscopic factors (or g factor) and line widths of paramagnetic species. A great number of the samples showed in their spectra, the presence of iron complexes. Phyllite and shale showed a resonance signal with approximately g = 2, and line width with about 1000 Gauss, which indicates the presence of the hematite mineral hematite in these rocks. Shale and coal samples showed the presence of free radical, it was identified as a very intense signal, centered at about g = 2.003. Phyllite sample showed in its spectra a resonance signal between the third and fourth line of the g marker (Mg O:Mn{sup 2+}) used in the measurements, and also a signal at g = 4.3, these characteristics may indicate the presence of Kaolinite in the sample. Limestone showed a signal with line width of about 600 Gauss, centered around g = 2, this signal is probably due to a mixture of ferrihydrite and some other compound, besides the presence of manganese, displaying a spectra with its six peculiar lines, due to hyperfine splitting. The two different types of limestone presented a overlap of two distinct spectra lines for the manganese, in the first limestone sample, rich in calcite, the existence of these different spectra is a result of the manganese substitution in a single site with different orientations of the calcite; the other limestone sample, this one abundant in dolomite, the existence of these different spectra is the result of the manganese substitution in different dolomite sites, taking the place of calcium and or of the magnesium. Now, we are focusing our research in the

  9. Application of electron paramagnetic resonance to identify irradiated soybean

    Bhaskar, S.; Behere, Arun; Sharma, Arun

    2006-01-01

    Full text: Electron paramagnetic resonance spectroscopy was applied to study free radicals in soy bean seed after gamma irradiation and to establish the potential of these radiation induced free radicals as the indicator of the radiation treatment. The radiation doses administered to the samples were 1 to 30 kGy. A stable doublet signal was detected at g = 2.0279 with hyperfine coupling constant of 2.8 mT, produced only by radiolysis. This signal can be used to identify irradiated soy bean seed samples. With the increase of the radiation dose the central line intensity and the intensities of the satellite lines showed almost a linear rise having linear correlation factors of 0.99724 and 0.99996, respectively. Thermal treatment at 373 deg K in air was studied. No line specific to thermolysis was observed. The spectrometer was operated with power 0.253 mW, microwave frequency 9.74 GHz, modulation frequency 100 kHz and scan range 10 mT. To study the stability of the signal, EPR spectra were obtained from the irradiated skin part of soy bean seeds samples following 1 and 90 days of storage after radiation treatment. The two satellite lines of g left = 2.0279 and g right 1.99529 were detected in all samples. This suggests that the signal is associated with a stable radical and therefore, the detection of a particular free radical as a marker of irradiation is proposed

  10. Electron paramagnetic resonance studies on silver atoms and clusters in regularly interstratified clay minerals

    Yamada, H.; Tamura, K.; Shimomura, S.; Sadlo, J.; Turek, J.; Michalik, J.

    2004-01-01

    The formation and stabilization of reduced silver species in the regularly interstratified clay minerals, trioctahedral smectite/chlorite (tri-Sm/Ch) and dioctahedral smectite/mica (di-Sm/M), have been studied by electron paramagnetic resonance (EPR) spectroscopy. Both minerals loaded with Ag + cations after degassing and dehydration were γ-irradiated at 77 K and monitored by EPR as the temperature increased. Some samples were exposed to water or methanol vapor after dehydration. In both hydrated and dehydrated samples only the doublets to Ag 0 atoms were observed with no evidence of the formation of Ag clusters. However, the EPR parameter of silver atoms in both matrices are different. In tri-Sm/Ch the narrow anisotropic EPR lines overlap with the broader isotropic lines, whereas in di-Sm/M only broad lines are recorded. The hyperfine splitting - A iso (Ag 0 ) is larger in tri-Sm/Ch than in di-Sm/M. Also the stability of Ag 0 in both clay minerals is distinctly different. Ag 0 doublet in di-Sm/M disappears completely above 230 K, Whereas in tri-Sm/Ch it is still recorded at 310 K. It is proposed, basing on the EPR results that Ag 0 atoms appear at different sites in both matrices: - in tri-Sm/Ch in the middle of smectite interlayer and in hexagonal cavities in the silicate sheets of tetrahedron layer and in di-Sm.M in hexagonal cavities only. When samples had been exposed to methanol before irradiation, the silver clusters become stabilized in the interlayer sites. In tri-Sm/M matrix the silver dimer Ag 2 + formed by gamma-irradiation at 77 K is transformed to tetrameric cluster, Ag 4 + at 150 K. In di-Sm/M the radiation-induced silver agglomeration proceeds in a similar way, but with a slower rate and Ag tetramer is formed only above 190 K. In both clay minerals, Ag 4 + clusters decay above 250 K. (author)

  11. Electron paramagnetic resonance of transition ions

    Abragam, Anatole

    1970-01-01

    This book is a reissue of a classic Oxford text, and provides a comprehensive treatment of electron paramagnetic resonance of ions of the transition groups. The emphasis is on basic principles, with numerous references to publications containing further experimental results and more detailed developments of the theory. An introductory survey gives a general understanding, and a general survey presents such topics as the classical and quantum resonance equations, thespin-Hamiltonian, Endor, spin-spin and spin-lattice interactions, together with an outline of the known behaviour of ions of each

  12. Electron paramagnetic resonance (EPR) in medical dosimetry

    Schauer, David A.; Iwasaki, Akinori; Romanyukha, Alexander A.; Swartz, Harold M.; Onori, Sandro

    2006-01-01

    This paper describes the fundamentals of electron paramagnetic resonance (EPR) and its application to retrospective measurements of clinically significant doses of ionizing radiation. X-band is the most widely used in EPR dosimetry because it represents a good compromise between sensitivity, sample size and water content in the sample. Higher frequency bands (e.g., W and Q) provide higher sensitivity, but they are also greatly influenced by water content. L and S bands can be used for EPR measurements in samples with high water content but they are less sensitive than X-band. Quality control for therapeutic radiation facilities using X-band EPR spectrometry of alanine is also presented

  13. Novel preconcentration technique for on-line coupling to high-speed narrow-bore capillary gas chromatography: sample enrichment by equilibrium (ab)sorption, I: Principles and theoretical aspects

    Pham Tuan, H.; Janssen, J.G.M.; Cramers, C.A.M.G.

    1997-01-01

    In recent years, there has been substantial progress in the field of high-speed narrow-bore capillary gas chromatography (GC) in general, and in the development of (trans)portable gas chromatographs for fast and accurate analysis in field applications in particular. Due to the limited

  14. Narrow beam neutron dosimetry.

    Ferenci, M Sutton

    2004-01-01

    Organ and effective doses have been estimated for male and female anthropomorphic mathematical models exposed to monoenergetic narrow beams of neutrons with energies from 10(-11) to 1000 MeV. Calculations were performed for anterior-posterior, posterior-anterior, left-lateral and right-lateral irradiation geometries. The beam diameter used in the calculations was 7.62 cm and the phantoms were irradiated at a height of 1 m above the ground. This geometry was chosen to simulate an accidental scenario (a worker walking through the beam) at Flight Path 30 Left (FP30L) of the Weapons Neutron Research (WNR) Facility at Los Alamos National Laboratory. The calculations were carried out using the Monte Carlo transport code MCNPX 2.5c.

  15. About kinetics of paramagnetic radiation malformations in beryllium ceramics

    Polyakov, A.I.; Ryabinkin, Yu.A.; Zashkvara, O.V.; Bitenbaev, M.I.; Petukhov, Yu.V.

    1999-01-01

    This paper [1] specifies that γ-radiation of the beryllium-oxide-based ceramics results in development of paramagnetic radiation malformations emerging the ESR spectrum in form of doublet with the splitting rate of oestrasid Δ∼1.6 and g-factor of 2.008. This report presents evaluation outcomes of dependence of paramagnetic radiation malformations concentration in beryllium ceramics on gamma-radiation dose ( 60 Co) within the range of 0-100 Mrad. Total paramagnetic parameters of beryllium ceramics in the range 0-100 Mrad of gamma-radiation dose varied slightly, and were specified by the first type of paramagnetic radiation malformations

  16. Experimental determination of the radial dose distribution in high gradient regions around 192Ir wires: Comparison of electron paramagnetic resonance imaging, films, and Monte Carlo simulations

    Kolbun, N.; Leveque, Ph.; Abboud, F.; Bol, A.; Vynckier, S.; Gallez, B.

    2010-01-01

    Purpose: The experimental determination of doses at proximal distances from radioactive sources is difficult because of the steepness of the dose gradient. The goal of this study was to determine the relative radial dose distribution for a low dose rate 192 Ir wire source using electron paramagnetic resonance imaging (EPRI) and to compare the results to those obtained using Gafchromic EBT film dosimetry and Monte Carlo (MC) simulations. Methods: Lithium formate and ammonium formate were chosen as the EPR dosimetric materials and were used to form cylindrical phantoms. The dose distribution of the stable radiation-induced free radicals in the lithium formate and ammonium formate phantoms was assessed by EPRI. EBT films were also inserted inside in ammonium formate phantoms for comparison. MC simulation was performed using the MCNP4C2 software code. Results: The radical signal in irradiated ammonium formate is contained in a single narrow EPR line, with an EPR peak-to-peak linewidth narrower than that of lithium formate (∼0.64 and 1.4 mT, respectively). The spatial resolution of EPR images was enhanced by a factor of 2.3 using ammonium formate compared to lithium formate because its linewidth is about 0.75 mT narrower than that of lithium formate. The EPRI results were consistent to within 1% with those of Gafchromic EBT films and MC simulations at distances from 1.0 to 2.9 mm. The radial dose values obtained by EPRI were about 4% lower at distances from 2.9 to 4.0 mm than those determined by MC simulation and EBT film dosimetry. Conclusions: Ammonium formate is a suitable material under certain conditions for use in brachytherapy dosimetry using EPRI. In this study, the authors demonstrated that the EPRI technique allows the estimation of the relative radial dose distribution at short distances for a 192 Ir wire source.

  17. Thermoelectricity in correlated narrow-gap semiconductors

    Tomczak, Jan M.

    2018-05-01

    We review many-body effects, their microscopic origin, as well as their impact on thermoelectricity in correlated narrow-gap semiconductors. Members of this class—such as FeSi and FeSb2—display an unusual temperature dependence in various observables: insulating with large thermopowers at low temperatures, they turn bad metals at temperatures much smaller than the size of their gaps. This insulator-to-metal crossover is accompanied by spectral weight-transfers over large energies in the optical conductivity and by a gradual transition from activated to Curie–Weiss-like behaviour in the magnetic susceptibility. We show a retrospective of the understanding of these phenomena, discuss the relation to heavy-fermion Kondo insulators—such as Ce3Bi4Pt3 for which we present new results—and propose a general classification of paramagnetic insulators. From the latter, FeSi emerges as an orbital-selective Kondo insulator. Focussing on intermetallics such as silicides, antimonides, skutterudites, and Heusler compounds we showcase successes and challenges for the realistic simulation of transport properties in the presence of electronic correlations. Further, we explore new avenues in which electronic correlations may contribute to the improvement of thermoelectric performance.

  18. Magneto-Optical Properties of Paramagnetic Superrotors

    Milner, A. A.; Korobenko, A.; Floß, J.; Averbukh, I. Sh.; Milner, V.

    2015-07-01

    We study the dynamics of paramagnetic molecular superrotors in an external magnetic field. An optical centrifuge is used to create dense ensembles of oxygen molecules in ultrahigh rotational states. In is shown, for the first time, that the gas of rotating molecules becomes optically birefringent in the presence of a magnetic field. The discovered effect of "magneto-rotational birefringence" indicates the preferential alignment of molecular axes along the field direction. We provide an intuitive qualitative model, in which the influence of the applied magnetic field on the molecular orientation is mediated by the spin-rotation coupling. This model is supported by the direct imaging of the distribution of molecular axes, the demonstration of the magnetic reversal of the rotational Raman signal, and by numerical calculations.

  19. Thermal properties of paramagnetic solid helium 3

    Goldstein, L.

    1983-01-01

    It was shown in recent work that over a limited molar volume range and at asymptotically high temperatures the thermal modulations of the pressure along isochores of paramagnetic solid 3 He could be accounted for through the formalism of the Heisenberg model of an antiferromagnetically interacting localized spin- 1/2 system. The internal consistency of this formalism requires the characteristic exchange-interaction parameter of the model derived from pressure modulation data to be identical with that appearing in the other thermal properties of this quantum solid. In a restricted temperature region where the spin excitations are the dominant thermal excitations of the solid, heat capacity data yield exchange-interaction parameters in fair agreement with those derived from pressures along isochores of larger molar volume. At higher temperatures, within well-defined limitations, thermal excitations involve both spin and phononexcitations. Here, because of the opposite temperature variations of the spin and phonon heat capacity components, the ensuing heat capacity minimum determines exactly the exchange-energy parameter and the relevant limiting Debye temperature as a function of the measured temperature location and value of the heat capacity extremum along the experimentally explored isochore. The exchange-energy parameters so derived display larger deviations from their predicted pressure-based values than those resulting from the lower temperature but still asymptotic spin-only heat capacities. At the present time, ambiguities in the experimental determinations of the characteristic Weiss temperatures of the asymptotic paramagnetic susceptibilities prevent one from deriving exchange-energy parameters with them. The present work leads to the prediction, within the limitations of the model formalism, of thermal properties of magnetized solid 3 He

  20. Narrow, duplicated internal auditory canal

    Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

    2003-05-01

    A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

  1. Enamel dose calculation by electron paramagnetic resonance spectral simulation technique

    Dong Guofu; Cong Jianbo; Guo Linchao; Ning Jing; Xian Hong; Wang Changzhen; Wu Ke

    2011-01-01

    Objective: To optimize the enamel electron paramagnetic resonance (EPR) spectral processing by using the EPR spectral simulation method to improve the accuracy of enamel EPR dosimetry and reduce artificial error. Methods: The multi-component superimposed EPR powder spectral simulation software was developed to simulate EPR spectrum models of the background signal (BS) and the radiation- induced signal (RS) of irradiated enamel respectively. RS was extracted from the multi-component superimposed spectrum of irradiated enamel and its amplitude was calculated. The dose-response curve was then established for calculating the doses of a group of enamel samples. The result of estimated dose was compared with that calculated by traditional method. Results: BS was simulated as a powder spectrum of gaussian line shape with the following spectrum parameters: g=2.00 35 and Hpp=0.65-1.1 mT, RS signal was also simulated as a powder spectrum but with axi-symmetric spectrum characteristics. The spectrum parameters of RS were: g ⊥ =2.0018, g ‖ =1.9965, Hpp=0.335-0.4 mT. The amplitude of RS had a linear response to radiation dose with the regression equation as y=240.74x + 76 724 (R 2 =0.9947). The expectation of relative error of dose estimation was 0.13. Conclusions: EPR simulation method has improved somehow the accuracy and reliability of enamel EPR dose estimation. (authors)

  2. Measurements of Narrow Mg II Associated Absorption Doublets with ...

    2016-01-27

    Jan 27, 2016 ... The measurement of the variations of absorption lines over time is a good method to study the physical conditions of absorbers. In this paper, we measure the variations of the line strength of 36 narrow Mg II2796, 2803 associated absorption doublets, which are imprinted on 31 quasar spectra with two ...

  3. Microstrip resonators for electron paramagnetic resonance experiments

    Torrezan, A. C.; Mayer Alegre, T. P.; Medeiros-Ribeiro, G.

    2009-07-01

    In this article we evaluate the performance of an electron paramagnetic resonance (EPR) setup using a microstrip resonator (MR). The design and characterization of the resonator are described and parameters of importance to EPR and spin manipulation are examined, including cavity quality factor, filling factor, and microwave magnetic field in the sample region. Simulated microwave electric and magnetic field distributions in the resonator are also presented and compared with qualitative measurements of the field distribution obtained by a perturbation technique. Based on EPR experiments carried out with a standard marker at room temperature and a MR resonating at 8.17 GHz, the minimum detectable number of spins was found to be 5×1010 spins/GHz1/2 despite the low MR unloaded quality factor Q0=60. The functionality of the EPR setup was further evaluated at low temperature, where the spin resonance of Cr dopants present in a GaAs wafer was detected at 2.3 K. The design and characterization of a more versatile MR targeting an improved EPR sensitivity and featuring an integrated biasing circuit for the study of samples that require an electrical contact are also discussed.

  4. Paramagnetic centers in AlQ3

    Grecu, M. N.; Mirea, A.; Schwoerer, M.; Grecu, V. V.

    2004-01-01

    Since the discovery in 1987 of its electroluminescent properties, Alq 3 (tris(8-hydroxyquinoline)aluminum(III)) has become one of the most used material in OLEDs (organic light-emitting diodes). Many researches have been carried out for improving its quantum efficiency of light emission. In spite of these, rather many fundamental questions concerning its properties, their dependence on thermal and annealing treatments and crystalline structure remained unanswered. Recently, a significant blue shift of luminescent spectrum of a specially treated fraction (so called δ-phase) has been reported, increasing even more the interest in such a material. In this contribution we shall report on the existence of paramagnetic centers in different Alq 3 fractions formed by using the train sublimation method, as well as in those which have undergone various thermal treatments. Several centers have been observed by cw X- and Q-band EPR spectroscopy, corresponding to spin 1/2 and even spin 3/2. The spin Hamiltonian parameters are given, the temperature dependencies are reported and proposals for model structures are made. (author)

  5. Microstrip resonators for electron paramagnetic resonance experiments.

    Torrezan, A C; Mayer Alegre, T P; Medeiros-Ribeiro, G

    2009-07-01

    In this article we evaluate the performance of an electron paramagnetic resonance (EPR) setup using a microstrip resonator (MR). The design and characterization of the resonator are described and parameters of importance to EPR and spin manipulation are examined, including cavity quality factor, filling factor, and microwave magnetic field in the sample region. Simulated microwave electric and magnetic field distributions in the resonator are also presented and compared with qualitative measurements of the field distribution obtained by a perturbation technique. Based on EPR experiments carried out with a standard marker at room temperature and a MR resonating at 8.17 GHz, the minimum detectable number of spins was found to be 5 x 10(10) spins/GHz(1/2) despite the low MR unloaded quality factor Q0=60. The functionality of the EPR setup was further evaluated at low temperature, where the spin resonance of Cr dopants present in a GaAs wafer was detected at 2.3 K. The design and characterization of a more versatile MR targeting an improved EPR sensitivity and featuring an integrated biasing circuit for the study of samples that require an electrical contact are also discussed.

  6. Electron paramagnetic resonance dosimetry using synthetic hydroxyapatite

    Choi, Kwon; Kim, Hwi Young; Ye, Sung Joon [Seoul National University, Seoul (Korea, Republic of); Hirata, Hiroshi [Hokkaido University, Sapporo (Japan); Park, Jong Min [Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-11-15

    The victims exposed doses under 3.5-4.0 Gy have chance to survive if treated urgently. To determine the priority of treatment among a large number of victims, the triage – distinguishing patients who need an urgent treatment from who may not be urgent – is necessary based on radiation biodosimetry. A current gold standard for radiation biodosimetry is the chromosomal assay using human lymphocytes. But this method requires too much time and skilled labors to cover the mass victims in radiation emergencies. Electron paramagnetic resonance (EPR) has been known for its capability of quantifying radicals in matters. EPR dosimetry is based on the measurement of stable radiation-induced radicals in tooth enamel. Hydroxyapatite (HAP) (Ca10(PO4)6(OH)2) contained in tooth enamel is a major probe for radiation dose reconstruction. This HAP dosimetry study was performed using a novel EPR spectrometer in Hokkaido University, Japan. The EPR dose-response curve was made using HAP samples. The blind test using 250 cGy samples showed the feasibility of EPR dosimetry for the triage purpose.

  7. Paramagnetic Nanoparticles Leave Their Mark on Nuclear Spins of Transiently Adsorbed Proteins.

    Zanzoni, Serena; Pedroni, Marco; D'Onofrio, Mariapina; Speghini, Adolfo; Assfalg, Michael

    2016-01-13

    The successful application of nanomaterials in biosciences necessitates an in-depth understanding of how they interface with biomolecules. Transient associations of proteins with nanoparticles (NPs) are accessible by solution NMR spectroscopy, albeit with some limitations. The incorporation of paramagnetic centers into NPs offers new opportunities to explore bio-nano interfaces. We propose NMR paramagnetic relaxation enhancement as a new tool to detect NP-binding surfaces on proteins with increased sensitivity, also extending the applicability of NMR investigations to heterogeneous biomolecular mixtures. The adsorption of ubiquitin on gadolinium-doped fluoride-based NPs produced residue-specific NMR line-broadening effects mapping to a contiguous area on the surface of the protein. Importantly, an identical paramagnetic fingerprint was observed in the presence of a competing protein-protein association equilibrium, exemplifying possible interactions taking place in crowded biological media. The interaction was further characterized using isothermal titration calorimetry and upconversion emission measurements. The data indicate that the used fluoride-based NPs are not biologically inert but rather are capable of biomolecular recognition.

  8. On superfluorescent generation of coherent radiation in a paramagnet

    Turaev, M.T.; Shumovsky, A.S.

    1988-08-01

    An exact definition is given of a superradiation intensity for a free system and for a system in cavity. The superradiant generation of the Zeeman transitions in proton paramagnet is described. (author). 7 refs, 2 figs

  9. On some paramagnetic species induced in natural calcites by β and γ-rays irradiations

    Rossi, A.; Danon, J.

    1985-01-01

    The ESR absorption lines of calcite speleothems are studied both as monocrystals and powders, after energetic β-rays or γ-rays irradiation. Both Kinds of irradiation produce same lines. Angular variation studies of monocrystals revealed four induced paramagnetic species stable at room temperature. Three of these were attributed to CO 3 sup(---) group, CO 2 sup(-) groups with axial and orthorhombic symetry and a fourth one could be due to the CO 3 sup(-) group. Powder spectra show that these lines, are activated by irradiation in all speleothems we studied and can be present either in natural ESR spectra. Their relationships to the lines usually considered for ESR dating are discussed. (Author) [pt

  10. Dosimetry of ionizing radiations by Electron paramagnetic resonance

    Azorin N, J.

    2005-01-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  11. Flooding correlations in narrow channel

    Kim, S. H.; Baek, W. P.; Chang, S. H.

    1999-01-01

    Heat transfer in narrow gap is considered as important phenomena in severe accidents in nuclear power plants. Also in heat removal of electric chip. Critical heat flux(CHF) in narrow gap limits the maximum heat transfer rate in narrow channel. In case of closed bottom channel, flooding limited CHF occurrence is observed. Flooding correlations will be helpful to predict the CHF in closed bottom channel. In present study, flooding data for narrow channel geometry were collected and the work to recognize the effect of the span, w and gap size, s were performed. And new flooding correlations were suggested for high-aspect-ratio geometry. Also, flooding correlation was applied to flooding limited CHF data

  12. Narrow n anti n resonances

    Bogdanova, L.N.; Dalkarov, O.D.; Kerbikov, B.O.; Shapiro, I.S.

    1975-01-01

    The present status of the problem of quasinuclear states in systems of nucleons and antinucleons is reviewed. The theoretical predictions are compared with experimental data on narrow meson resonances near N anti N threshold which appeared in 1971-74

  13. Conventional electron paramagnetic resonance of Mn2+ in synthetic hydroxyapatite at different concentrations of the doped manganese

    Murzakhanov, F.; Mamin, G.; Voloshin, A.; Klimashina, E.; Putlyaev, V.; Doronin, V.; Bakhteev, S.; Yusupov, R.; Gafurov, M.; Orlinskii, S.

    2018-05-01

    Powders of synthetic hydroxyapatite doped with Mn2+ ions in concentrations from 0.05 till 5 wt. % were investigated by conventional electron paramagnetic resonance (EPR). The parameters of the spin-Hamiltonian are derived. Partially resolved hyperfine structure in the magnetic fields corresponding to g ≈ 4.3 and g ≈ 9.4 is observed. The narrowing of the central peak with concentration is reported. A possibility to use the linewidth and intensity of the central peak for concentration measurements are discussed. The results could be used for the identification and qualification of Mn2+ in oil, mining and ore formations.

  14. Electron paramagnetic resonance of atomic hydrogen (H0) centers in pink tourmaline from Brazil

    Camargo, M.B.

    1985-01-01

    A model for explaining the atom of hydrogen (H 0 ) in pink tourmaline irradiated with gamma rays is presented. The concentration of H 0 was evaluated and the H 0 lines using the electron paramagnetic resonance were analysed. The g factor and the hyperfine interaction constant were measured with accuracy and determined by matrix diagonalization of spin hamiltonian in vetor space of four dimensions, followed by an iterative calculation with quick convergence the local electric field produced by charges in the lattice was calculated and compared with the value obtained experimentally. (M.C.K.) [pt

  15. Electron paramagnetic resonance dosimetry in fingernails

    Romanyukha, Alex; Benevides, Luis A.; Reyes, Ricardo; Trompier, Francois; Clairand, Isabelle; Swartz, Harold M.

    2008-01-01

    Full text: Based on the capabilities of new instrumentation and the experience gained in the use of teeth for 'after-the-fact' dosimetry, we have undertaken a systematic electron paramagnetic resonance (EPR) study of irradiated fingernails. There have been only a modest number of previous studies of radiation-induced signals in fingernails. While these have given us some promising aspects, overall results have been inconsistent. The most significant problem of EPR fingernail dosimetry is the presence of two signals of non-radiation origin that overlap the radiation-induced signal (RIS), making it almost impossible to do dose measurements below 5 Gy. Historically, these two non-radiation components were named mechanically-induced signal (MIS) and background signal (BKS). In order to investigate them in detail, three different methods of MIS and BKS mutual isolation have been developed and implemented. Having applied these methods, we were able to understand that fingernail tissue, after cut, can be modeled as a deformed sponge, where the MIS and BKS are associated with the stress from elastic and plastic deformations respectively. A sponge has a unique mechanism of mechanical stress absorption, which is necessary for fingernails in order to perform its everyday function of protecting the fingertips from hits and trauma. Like a sponge, fingernails are also known to be an effective water absorber. When a sponge is saturated with water, it tends to restore to its original shape, and when it looses water, it becomes deformed again. The same happens to fingernail tissue. Our suggested interpretation of the mechanical deformation in fingernails gives also a way to distinguish between the MIS and RIS. Obtained results show that the MIS in irradiated fingernails can be almost completely eliminated without a significant change to the RIS by soaking the sample for 10 minutes in water. This is an ongoing study but even at its present state of development, it has shown that it

  16. Proton nuclear magnetic resonance in paramagnetic CoCl2.6H2O

    Oravcova, J.; Murin, J.; Rakos, M.; Olcak, D.

    1978-01-01

    Nuclear magnetic resonance (NMR) is studied of protons of the crystal water of paramagnetic CoCl 2 .6H 2 O. The measurements were carried out on powdered samples at room temperature, for values of the external magnetic field ranging from 0.3 to 1.0 T. The NMR signals of protons of the crystal water exhibit asymmetric shape which changes with the applied external magnetic field. We found that the second moment of the resonance line shows a linear dependence on the square of the induction of the externally applied magnetic field. The cause of the asymmetry of the NMR line of protons of the crystal water and the dependence of the second moment of the resonance line on the induction of external magnetic field are interpreted. (author)

  17. Paramagnetic centers in nanocrystalline TiC/C system

    Guskos, N.; Bodziony, T.; Maryniak, M.; Typek, J.; Biedunkiewicz, A.

    2008-01-01

    Electron paramagnetic resonance is applied to study the defect centers in nanocrystalline titanium carbide dispersed in carbon matrix (TiC x /C) synthesized by the non-hydrolytic sol-gel process. The presence of Ti 3+ paramagnetic centers is identified below 120 K along with a minor contribution from localized defect spins coupled with the conduction electron system in the carbon matrix. The temperature dependence of the resonance intensity of the latter signal indicates weak antiferromagnetic interactions. The presence of paramagnetic centers connected with trivalent titanium is suggested to be the result of chemical disorder, which can be further related to the observed anomalous behavior of conductivity, hardness, and corrosion resistance of nanocrystalline TiC x /C

  18. Paramagnetic resonance and electronic conduction in organic semiconductors

    Nechtschein, M.

    1963-01-01

    As some organic bodies simultaneously display semi-conducting properties and a paramagnetism, this report addresses the study of conduction in organic bodies. The author first briefly recalls how relationships between conductibility and Electron Paramagnetic Resonance (EPR) can be noticed in a specific case (mineral and metallic semiconductors). He discusses published results related to paramagnetism and conductibility in organic bodies. He reviews various categories of organic bodies in which both properties are simultaneously present. He notably addresses radical molecular crystals, non-radical molecular crystals, charge transfer complexes, pyrolyzed coals, and pseudo-ferromagnetic organic structures. He discusses the issue of relationships between conduction (charge transfer by electrons) and ERP (which reveals the existence of non-paired electrons which provide free spins)

  19. Electron paramagnetic resonance of rhyolite and γ-irradiated trona minerals

    Koeksal, F.; Koeseoglu, R.; Basaran, E.

    2003-01-01

    Rhyolite from the ''Yellow Stone of Nevsehir'' and γ-irradiated trona from the Ankara Mine have been investigated by electron paramagnetic resonance at ambient temperature and at 113 K. Rhyolite was examined by X-ray powder diffraction and found to consist mainly of SiO 2 . Before γ-irradiation, the existing paramagnetic species in rhyolite were identified as PO 4 2- , CH 2 OH, CO 3 - , SO 2 - , CO 3 3- , and CO 2 - free radicals and Fe 3+ at ambient temperature. At 113 K SO 2 - , CO 3 3- , and CO 2 - radicals and Fe 3+ were observed. The γ-irradiation produced neither new species nor detectable effects on these free radicals. The disappearance of some of the radicals at 113 K is attributed to the freezing of their motions. Before γ-irradiation, the trona mineral shows only Mn 2+ lines, but after γ-irradiation it indicated the inducement of CO 3 3- and CO 2 - radicals at ambient temperature, 113 K, in addition to the Mn 2+ lines. The g and a values of the species were determined. (orig.)

  20. Intrinsic Electric Dipole Moments of Paramagnetic Atoms: Rubidium and Cesium

    Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.

    2008-01-01

    The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar--pseudo-scalar (S-PS) electron-nucleus interactions. The electron EDM and the S-PS EDM contribution to atomic EDM scales as Z^3. Thus, the heavy paramagnetic atomic systems will exhibit large enhancement factors. However, the nature of the coupling is so small that it becomes an interest of high precision atomic experiments. In this work, we...

  1. Modified Sucksmith balances for ferromagnetic and paramagnetic measurements

    Lundquist, N; Myers, H P

    1962-02-15

    Two balances, one for measurement of ferromagnetic magnetisation, the other for paramagnetic susceptibility measurements, are described. Designs are based on Sucksmith's ring balance but the ring and optical lever system of the latter has been replaced by a strain gauge bridge, which allows the force on the magnetic specimens to be determined via potentiometer readings. The modified balances are very robust, insensitive to vibration and, if desired, suitable for direct recording. Relative accuracies of 0.3 % and 0.5 % are obtained respectively for the ferromagnetic and paramagnetic systems.

  2. Probing Spin Crossover in a Solution by Paramagnetic NMR Spectroscopy.

    Pavlov, Alexander A; Denisov, Gleb L; Kiskin, Mikhail A; Nelyubina, Yulia V; Novikov, Valentin V

    2017-12-18

    Spin transitions in spin-crossover compounds are now routinely studied in the solid state by magnetometry; however, only a few methods exist for studies in solution. The currently used Evans method, which relies on NMR spectroscopy to measure the magnetic susceptibility, requires the availability of a very pure sample of the paramagnetic compound and its exact concentration. To overcome these limitations, we propose an alternative NMR-based technique for evaluating spin-state populations by only using the chemical shifts of a spin-crossover compound; those can be routinely obtained for a solution that contains unknown impurities and paramagnetic admixtures or is contaminated otherwise.

  3. Japanese VLBI Network Observations of a Gamma-Ray Narrow ...

    J. Astrophys. Astr. (2014) 35, 215–218 c Indian Academy of Sciences. Japanese VLBI Network Observations of a Gamma-Ray. Narrow-Line Seyfert 1 Galaxy 1H 0323+342. Kiyoaki Wajima1,∗. , Kenta Fujisawa2, Masaaki Hayashida3. & Naoki Isobe4. 1Shanghai Astronomical Observatory, Chinese Academy of Sciences,.

  4. Electronic paramagnetic resonance in the Mn In X (X:Te,S) diluted magnetic semiconductor system

    Vincent, Bernardo; Betancourt, Luis; Sagredo, Vicente; Alcala, Rafael

    1996-01-01

    Semiconductor compounds wit the II-III-VI stoichiometry are very interesting materials since they present very good semiconducting characteristics and, along with strong magnetic properties, these II Mn In VI compounds have a great potential as opt and magneto-electronic devices. Among the possible magnetic properties of the materials is the presence of the spin-glass phase. Electron paramagnetic resonance is one of the techniques used to confirm this phase. The chosen crystals were chosen by chemical vapor transport. The absorption lines of these two families with 0.1 x 1 were all Lorentzian in shape and centred at g=2. A large broadening of the resonance line width was observed when lowering the temperature to below 80 K. This behaviour was fitted to the known existing models, and good values of the calculated parameters were obtained (author)

  5. Towards improving the detection limit of electron paramagnetic resonance (EPR) dosimetry of drywall (wallboard)

    Mistry, R.; Thompson, J.W. [Dept. of Medical Physics and Applied Radiation Sciences, McMaster Univ., Hamilton, Ontario (Canada); Rink, W.J. [School of Geography and Earth Sciences, McMaster Univ., Hamilton, Ontario (Canada); Boreham, D. [Dept. of Medical Physics and Applied Radiation Sciences, McMaster Univ., Hamilton, Ontario (Canada)

    2009-07-01

    The intensity of the electron paramagnetic resonance (EPR) line corresponding to the carbonate free radical (CO{sub 3}{sup -}) in gypsum (CaSO{sub 4}{center_dot}2H{sub 2}O) drywall was previously shown to be proportional to absorbed dose. Heating irradiated drywall reduces the radiosensitive signal of the CO{sub 3}{sup -} radical. The response of the CO{sub 3}{sup -} EPR line to heat treatments is being studied in order to determine a background for an arbitrary drywall sample. Ultimately this is expected to improve the precision of dose measurements with drywall and to reduce the detection limit. Controlled heating of irradiated drywall was performed at temperatures between 50{sup o}C and 100{sup o}C. Although higher temperatures reduce the radiosensitive signal rapidly, the non-radiosensitive EPR signals are affected dramatically as well, presumably due to a phrase change from gypsum to plaster of Paris to anhydrite. (author)

  6. Dynamical magnetic response of paramagnetic CeFe-2

    Rainford, B.D.; McK Paul, D.; Warwick Univ., Coventry

    1988-01-01

    Inelastic neutron scattering has been used to study the energy dependence of the paramagnetic response from CeFe 2 . Our results, when integrated over energy, are in excellent agreement with the polarised neutron experiments of Deportes et al., but the correlation length obtained by fitting the data to a double Lorentzian scattering function is significantly smaller than that derived previously

  7. Intrinsic electric dipole moments of paramagnetic atoms : Rubidium and cesium

    Nataraj, H. S.; Sahoo, B. K.; Das, B. P.; Mukherjee, D.

    2008-01-01

    The electric dipole moment (EDM) of paramagnetic atoms is sensitive to the intrinsic EDM contribution from that of its constituent electrons and a scalar-pseudoscalar (S-PS) electron-nucleus interaction. The electron EDM and the S-PS contributions to the EDMs of these atoms scale as approximate to

  8. Introduction to Spin Label Electron Paramagnetic Resonance Spectroscopy of Proteins

    Melanson, Michelle; Sood, Abha; Torok, Fanni; Torok, Marianna

    2013-01-01

    An undergraduate laboratory exercise is described to demonstrate the biochemical applications of electron paramagnetic resonance (EPR) spectroscopy. The beta93 cysteine residue of hemoglobin is labeled by the covalent binding of 3-maleimido-proxyl (5-MSL) and 2,2,5,5-tetramethyl-1-oxyl-3-methyl methanethiosulfonate (MTSL), respectively. The excess…

  9. Some examples of utilization of electron paramagnetic resonance in biology

    Bemski, G.

    1982-10-01

    A short outline of the fundamentals of electron paramagnetic resonance (EPR) is presented and is followed by examples of the application of EPR to biology. These include use of spin labels, as well as of ENDOR principally to problems of heme proteins, photosynthesis and lipids. (Author) [pt

  10. WOHLLEBEN EFFECT (PARAMAGNETIC MEISSNER EFFECT) IN HIGH-TEMPERATURE SUPERCONDUCTORS

    KHOMSKII, D

    Recently a quite unexpected phenomenon was observed during the study of the magnetic properties of High-T(c) superconductors: In the field-cooled regime the magnetic response of some HTSC at very low fields (less than or similar to 1 Oe), instead of being diamagnetic, becomes paramagnetic. Such

  11. Magnon spin Hall magnetoresistance of a gapped quantum paramagnet

    Ulloa, Camilo; Duine, R.A.

    2018-01-01

    Motivated by recent experimental work, we consider spin transport between a normal metal and a gapped quantum paramagnet. We model the latter as the magnonic Mott-insulating phase of an easy-plane ferromagnetic insulator. We evaluate the spin current mediated by the interface exchange coupling

  12. A direct simulation method for flows with suspended paramagnetic particles

    Kang, T.G.; Hulsen, M.A.; Toonder, den J.M.J.; Anderson, P.D.; Meijer, H.E.H.

    2008-01-01

    A direct numerical simulation method based on the Maxwell stress tensor and a fictitious domain method has been developed to solve flows with suspended paramagnetic particles. The numerical scheme enables us to take into account both hydrodynamic and magnetic interactions between particles in a

  13. Nonequilibrium ensembles. 3. Spin 1/2 paramagnets

    Sobouti, Y.; Khajeh-Pour, M.R.H.

    1990-07-01

    The thermodynamic state of a paramagnetic substance in which the spin vectors precess coherently is investigated. The state is a time dependent one. The corresponding density matrix and the thermodynamics emerging from it is worked out. A laboratory preparation of such a system is discussed. (author). 3 refs

  14. Dynamics in photosynthetic transient complexes studied by paramagnetic NMR spectroscopy

    Scanu, Sandra

    2013-01-01

    This PhD thesis focuses on fundamental aspects of protein-protein interactions. A multidisciplinary methodology for the detection and visualization of transient, lowly-populated encounter protein complexes is described. The new methodology combined paramagnetic NMR spectroscopy with computational

  15. Investigation of paramagnetic saturation in lanthanum manganese nitrate

    Flokstra, Jakob; Meijer, H.C.; Bots, G.J.C.; Verheij, W.A.; van der Marel, L.C.

    1973-01-01

    Paramagnetic saturation of lanthanum manganese nitrate, La2Mn3(NO3)12·24H2O, has been investigated at liquid He temperatures in a static as well as a dynamical way. With the aid of the molecular-field theory the Casimir and Du Pré dispersion and absorption curves are adapted explicitly to the

  16. Correlation induced paramagnetic ground state in FeAl

    Mohn, P.; Persson, C.; Blaha, P.; Schwarz, K.; Novák, Pavel; Eschrig, H.

    2001-01-01

    Roč. 87, č. 19 (2001), s. 196401-1-196401-4 ISSN 0031-9007 Institutional research plan: CEZ:AV0Z1010914 Keywords : FeAl * paramagnetic ground state Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 6.668, year: 2001

  17. CW EPR and 9 GHz EPR imaging investigation of stable paramagnetic species and their antioxidant activities in dry shiitake mushroom (Lentinus edodes).

    Nakagawa, Kouichi; Hara, Hideyuki

    2016-01-01

    We investigated the antioxidant activities and locations of stable paramagnetic species in dry (or drying) shiitake mushroom (Lentinus edodes) using continuous wave (CW) electron paramagnetic resonance (EPR) and 9 GHz EPR imaging. CW 9 GHz EPR detected paramagnetic species (peak-to-peak linewidth (ΔHpp) = 0.57 mT) in the mushroom. Two-dimensional imaging of the sharp line using a 9 GHz EPR imager showed that the species were located in the cap and shortened stem portions of the mushroom. No other location of the species was found in the mushroom. However, radical locations and concentrations varied along the cap of the mushroom. The 9 GHz EPR imaging determined the exact location of stable paramagnetic species in the shiitake mushroom. Distilled water extracts of the pigmented cap surface and the inner cap of the mushroom showed similar antioxidant activities that reduced an aqueous solution of 0.1 mM 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl. The present results suggest that the antioxidant activities of the edible mushroom extracts are much weaker than those of ascorbic acid. Thus, CW EPR and EPR imaging revealed the location and distribution of stable paramagnetic species and the antioxidant activities in the shiitake mushroom for the first time.

  18. New possibilities for using laser polarimetry technology to study electron paramagnetic resonance

    Aleksandrov, E V; Zapasskii, V S

    1982-01-01

    Optical methods of recording electron paramagnetic resonance which arose in the early 50's as applied to the problem of recording the magnetic resonance of excited atoms is at the present time widely used in studying the electron paramagnetic resonance of the ground and excited states of free atoms and paramagnetic centers in condensed media. At the present time attention is devoted to the additional possibilities of optical methods of electron paramagnetic resonance which are realized using laser sources.

  19. Line-narrowing in proton-detected nitrogen-14 NMR

    Cavadini, Simone; Vitzthum, Veronika; Ulzega, Simone; Abraham, Anuji; Bodenhausen, Geoffrey

    2010-01-01

    In solids spinning at the magic angle, the indirect detection of single-quantum (SQ) and double-quantum (DQ) 14N spectra ( I = 1) via spy nuclei S = 1/2 such as protons can be achieved in the manner of heteronuclear single- or multiple-quantum correlation (HSQC or HMQC) spectroscopy. The HMQC method relies on the excitation of two-spin coherences of the type T11IT11S and T21IT11S at the beginning of the evolution interval t1. The spectra obtained by Fourier transformation from t1 to ω1 may be broadened by the homogenous decay of the transverse terms of the spy nuclei S. This broadening is mostly due to homonuclear dipolar S- S' interactions between the proton spy nuclei. In this work we have investigated the possibility of inserting rotor-synchronized symmetry-based C or R sequences and decoupling schemes such as Phase-Modulated Lee-Goldburg (PMLG) sequences in the evolution period. These schemes reduce the homonuclear proton-proton interactions and lead to an enhancement of the resolution of both SQ and DQ proton-detected 14N HMQC spectra. In addition, we have investigated the combination of HSQC with symmetry-based sequences and PMLG and shown that the highest resolution in the 14N dimension is achieved by using HSQC in combination with symmetry-based sequences of the R-type. We show improvements in resolution in samples of L-alanine and the tripeptide ala-ala-gly (AAG). In particular, for L-alanine the width of the 14N SQ peak is reduced from 2 to 1.2 kHz, in agreement with simulations. We report accurate measurements of quadrupolar coupling constants and asymmetry parameters for amide 14N in AAG peptide bonds.

  20. Paramagnetic probes to study PrNi5?

    Hutchinson, W.D.; Harker, S.J.; Stewart, G.A.; Chaplin, D.H.; Kaplan, N.

    1996-01-01

    The Van-Vleck paramagnet PrNi 5 has been the focus of many studies in the past as a result of its usefulness as a nuclear cooling agent. Extensive continuous wave praseodymium NMR measurements have been carried out on this compound. However pulsed NMR and therefore precise relaxation measurements particularly at mK temperatures have proved elusive. In this work we have proposed to use radiative gamma-ray detection to indirectly measure Pr NMR in PrNi 5 via cross relaxation to suitable paramagnetic impurity probes placed at Ni lattice sites. 57 Co was chosen as the most compatible nuclear orientation isotope with an appropriate nuclear g-factor. The choice of 57 Co also allows the use of Moessbauer spectroscopy to check the site occupancy. This poster details the production of a 57 Co doped PrNi 5 single crystal specimen including the specimen preparation problems encountered, 57 Fe Moessbauer and preliminary nuclear orientation measurements

  1. Improved paramagnetic chelate for molecular imaging with MRI

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-01-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent

  2. Paramagnetic metal complexes as potential relaxation agents for NMR imaging

    Coroiu, Ilioara; Demco, D. E.; Darabont, Al.; Bogdan, M.

    1997-01-01

    The development of nuclear magnetic resonance (NMR) imaging technique as a clinical diagnostic modality has prompted the need for a new class of pharmaceuticals. These drugs must be administered to a patient in order to enhance the image contrast between the normal and diseased tissue and/or indicate the status of organ function or blood flow. Paramagnetic compounds are presently undergoing extensive evaluation as contrast agents in magnetic resonance imaging (MRI). These agents increase contrast in MRI by differentially localizing in tissue where they increase the relaxation rates of nearby water protons. The longitudinal R 1 and transverse R 2 relaxivities were measured as a function of molar concentrations for some new paramagnetic complexes like the following: dysprosium, erbium and gadolinium citrates, gadolinium methylene diphosphonate, dysprosium and gadolinium iminodiacetate, manganese para-aminobenzoate and copper nicotinate. The available theoretical approaches for quantitative understanding are presented. (authors)

  3. Improved paramagnetic chelate for molecular imaging with MRI

    Winter, Patrick; Athey, Phillip; Kiefer, Garry; Gulyas, Gyongyi; Frank, Keith; Fuhrhop, Ralph; Robertson, David; Wickline, Samuel; Lanza, Gregory

    2005-05-01

    The relaxivity and transmetallation of two lipophilic paramagnetic chelates incorporated onto perfluorocarbon nanoparticles, i.e., gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid phosphatidylethanolamine (Gd-MeO-DOTA-PE) and gadolinium-methoxy-tetraazacyclododecane-tetraacetic acid triglycine phosphatidylethanolamine (Gd-MeO-DOTA-triglycine-PE (Gd-MeO-DOTA-triglycine-PE)), were compared to a prototypic gadolinium-diethylene-triamine-pentaacetic acid bis-oleate (Gd-DTPA-BOA) paramagnetic formulation. Nanoparticles with MeO-DOTA-based chelates demonstrated higher relaxivity (40% higher for Gd-MeO-DOTA-PE and 55% higher for Gd-MeO-DOTA-triglycine-PE) and less transmetallation than the original Gd-DTPA-BOA-based agent.

  4. The paramagnetic effect in Type-I superconductors

    Rothen, F.; Lievre, C.

    1975-01-01

    The paramagnetic effect in superconductors was first observed by Steiner and Schoeneck in 1943. This effect takes place in a cylindrical wire if superconductivity is destroyed by a current J in the presence of a magnetic field He parallel to the axis: one notices that the average longitudinal magnetic induction inside the wire can greatly exceed He. An attempt is made to compute the maximal value of the longitudinal magnetic permeability of the current-carrying wire. (Auth.)

  5. Dynamic polarization in paramagnetic solids and microscopic correlation functions

    Boucher, Jean-Paul

    1972-01-01

    The different effects of Dynamic Nuclear Polarization in paramagnetic solids are described by means of a single thermodynamic formalism. In the case of large exchange interactions, the Overhauser effect correlated with nuclear relaxation time measurements can provide a way of studying correlation functions between electronic spins. This method is used to study the low-frequency behaviour of the microscopic spectral density which should diverge as ω → 0, in the case of a linear exchange chain. (author) [fr

  6. Paramagnetism and plasma beta in a screw-pinch

    Lehnert, B.; Scheffel, J.

    1991-02-01

    Anisotropic resistivity causes paramagnetic effects (B z ' (r) less then 0) in a screw pinch, being basically different to the self-relaxation described by Taylor. We compute, analytically and numerically, the resulting effect on equilibrium in a 1-D straight cylindrical plasma. In particular we compute paramagnetic effects on the plasma radius and on plasma beta. Ohm's law also contains diamagnetic terms; in this paper we consider radial particle diffusion and the Nernst effect. In a Tokamak or rector plasma these effects are shown to be negligible, whereas they may contribute in present ULQ, Extrap and RFP experiments. A basic result is an expression for the coupling between the poloidal and axial magnetic field components with the above effects included. A result of specific importance to the Extrap programme is that plasma current limitation can arise from lack of equilibrium when the plasma radius tends to exceed its upper limit, being defined by a magnetic or material limiter. The paramagnetic effect described in this work lowers the plasma beta further, making D-D reactor depending on safety factors q(a) bigger than 1 seems less attainable. (au)

  7. Crystallite arrangement of hydroxyapatite microcrystals in human tooth cementum as revealed by electron paramagnetic resonance (EPR)

    Skaleric, U.; Gaspirc, B.; Cevc, P.; Schara, M.

    1998-01-01

    Human dental cementum was analyzed by electron paramagnetic resonance (EPR). The measured EPR powder spectra of γ-irradiated cementum resembled those of γirradiated enamel. Both spectra were characterized by the same line shapes and g values. The position of the extreme first derivate peaks can be described by g 1 =2.0023 and g 2 =1.9971±0.0002, and are assignable to the CO 3 3- center. The angular dependence of the cementum EPR spectra indicates a different arrangement of the hydroxyapatite microcrystals compared to that of enamel. A corresponding model of cementum micro-crystal alignment has been proposed. The methodology presented can be utilized for studying the mineralization process of root cementum and other mineralized tissues. (au)

  8. Prospects for quantum computing with an array of ultracold polar paramagnetic molecules.

    Karra, Mallikarjun; Sharma, Ketan; Friedrich, Bretislav; Kais, Sabre; Herschbach, Dudley

    2016-03-07

    Arrays of trapped ultracold molecules represent a promising platform for implementing a universal quantum computer. DeMille [Phys. Rev. Lett. 88, 067901 (2002)] has detailed a prototype design based on Stark states of polar (1)Σ molecules as qubits. Herein, we consider an array of polar (2)Σ molecules which are, in addition, inherently paramagnetic and whose Hund's case (b) free-rotor pair-eigenstates are Bell states. We show that by subjecting the array to combinations of concurrent homogeneous and inhomogeneous electric and magnetic fields, the entanglement of the array's Stark and Zeeman states can be tuned and the qubit sites addressed. Two schemes for implementing an optically controlled CNOT gate are proposed and their feasibility discussed in the face of the broadening of spectral lines due to dipole-dipole coupling and the inhomogeneity of the electric and magnetic fields.

  9. Electron paramagnetic resonance and dynamic nuclear polarization of char suspensions: surface science and oximetry

    Clarkson, R.B.; Odintsov, B.M.; Ceroke, P.J.; Ardenkjaer-Larsen, J.H.; Fruianu, M.; Belford, R.L.

    1998-01-01

    Carbon chars have been synthesized in our laboratory from a variety of starting materials, by means of a highly controlled pyrolysis technique. These chars exhibit electron paramagnetic resonance (EPR) line shapes which change with the local oxygen concentration in a reproducible and stable fashion; they can be calibrated and used for oximetry. Biological stability and low toxicity make chars good sensors for in vivo measurements. Scalar and dipolar interactions of water protons at the surfaces of chars may be utilized to produce dynamic nuclear polarization (DNP) of the 1 H nuclear spin population in conjunction with electron Zeeman pumping. Low-frequency EPR, DNP and DNP-enhanced MRI all show promise as oximetry methods when used with carbon chars. (author)

  10. Nonlinear narrow Doppler-free resonances for optical transitions and annihilation radiation of a positronium atom

    Letokhov, V.S.; Minogin, V.G.

    1976-01-01

    The possibilities of obtaining narrow resonances without the Doppler broadening for transition between the fine structure levels of the ground and first excited states of a positronium atom are considered. An analysis is carried out of the conditions required for observation of the narrow resonances of saturation of single quantum absorption in the 1S-2P transitions and observation of narrow two-photon absorption resonances in the 1S-2S transitions. It is shown that narrow 2γ annihilation radiation lines of a positronium atom may be obtained with a width much smaller than the Doppler one

  11. Soliton generation via continuous stokes acoustic self-scattering of hypersonic waves in a paramagnetic crystal

    Bugay, A. N.; Sazonov, S. V.

    2008-01-01

    A new mechanism is proposed for continuous frequency down-conversion of acoustic waves propagating in a paramagnetic crystal at a low temperature in an applied magnetic field. A transverse hypersonic pulse generating a carrier-free longitudinal strain pulse via nonlinear effects is scattered by the generated pulse. This leads to a Stokes shift in the transverse hypersonic wave proportional to its intensity, and both pulses continue to propagate in the form of a mode-locked soliton. As the transverse-pulse frequency is Stokes shifted, its spectrum becomes narrower. This process can be effectively implemented only if the linear group velocity of the transverse hypersonic pulse equals the phase velocity of the longitudinal strain wave. These velocities are renormalized by spin-phonon coupling and can be made equal by adjusting the magnitude of the applied magnetic field. The transverse structure of the soliton depends on the sign of the group velocity dispersion of the transverse component. When the dispersion is positive, planar solitons can develop whose transverse component has a topological defect of dark vortex type and longitudinal component has a hole. In the opposite case, the formation of two-component acoustic 'bullets' or vortices localized in all directions is possible

  12. Automated genomic DNA purification options in agricultural applications using MagneSil paramagnetic particles

    Bitner, Rex M.; Koller, Susan C.

    2002-06-01

    The automated high throughput purification of genomic DNA form plant materials can be performed using MagneSil paramagnetic particles on the Beckman-Coulter FX, BioMek 2000, and the Tecan Genesis robot. Similar automated methods are available for DNA purifications from animal blood. These methods eliminate organic extractions, lengthy incubations and cumbersome filter plates. The DNA is suitable for applications such as PCR and RAPD analysis. Methods are described for processing traditionally difficult samples such as those containing large amounts of polyphenolics or oils, while still maintaining a high level of DNA purity. The robotic protocols have ben optimized for agricultural applications such as marker assisted breeding, seed-quality testing, and SNP discovery and scoring. In addition to high yield purification of DNA from plant samples or animal blood, the use of Promega's DNA-IQ purification system is also described. This method allows for the purification of a narrow range of DNA regardless of the amount of additional DNA that is present in the initial sample. This simultaneous Isolation and Quantification of DNA allows the DNA to be used directly in applications such as PCR, SNP analysis, and RAPD, without the need for separate quantitation of the DNA.

  13. Narrow gap electronegative capacitive discharges

    Kawamura, E.; Lieberman, M. A.; Lichtenberg, A. J. [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States)

    2013-10-15

    Narrow gap electronegative (EN) capacitive discharges are widely used in industry and have unique features not found in conventional discharges. In this paper, plasma parameters are determined over a range of decreasing gap length L from values for which an electropositive (EP) edge exists (2-region case) to smaller L-values for which the EN region connects directly to the sheath (1-region case). Parametric studies are performed at applied voltage V{sub rf}=500 V for pressures of 10, 25, 50, and 100 mTorr, and additionally at 50 mTorr for 1000 and 2000 V. Numerical results are given for a parallel plate oxygen discharge using a planar 1D3v (1 spatial dimension, 3 velocity components) particle-in-cell (PIC) code. New interesting phenomena are found for the case in which an EP edge does not exist. This 1-region case has not previously been investigated in detail, either numerically or analytically. In particular, attachment in the sheaths is important, and the central electron density n{sub e0} is depressed below the density n{sub esh} at the sheath edge. The sheath oscillations also extend into the EN core, creating an edge region lying within the sheath and not characterized by the standard diffusion in an EN plasma. An analytical model is developed using minimal inputs from the PIC results, and compared to the PIC results for a base case at V{sub rf}=500 V and 50 mTorr, showing good agreement. Selected comparisons are made at the other voltages and pressures. A self-consistent model is also developed and compared to the PIC results, giving reasonable agreement.

  14. The Paramagnetism of Dissolved Mn in {alpha} and {beta} Brasses

    Myers, H P; Westin, R

    1962-12-15

    Paramagnetic susceptibility measurements have been made on {alpha} and {beta} brasses containing {approx} 1 w/o Mn. The susceptibility varied with temperature according to the Curie Weiss law and the Curie constant and thereby the Bohr magneton number per Mn atom were determined. Interpreted in terms of valency, Mn monovalent in copper has a valency in {alpha} brass which decreases progressively with zinc content attaining the value 0.58 at the limiting of composition. Mn in {beta} brass exhibits a valency 0.8. These results are not in keeping with previous values for the valency of manganese as determined from phase boundary relationships and electron to atom ratios.

  15. Moessbauer effect and electron paramagnetic resonance studies on yeast aconitase

    Suzuki, Takashi; Maeda, Yutaka; Sakai, Hiroshi; Fujimoto, Shigeru; Morita, Yuhei.

    1975-01-01

    The Moessbauer effect and electron paramagnetic resonance (EPR) of yeast aconitase [EC 4.2.1.3] purified from the cells of Candida lipolytica (ATCC 20114) were measured. Moessbauer spectra suggested that yeast acontitase mostly contained two high-spin Fe(III) ions in an antiferromagnetically coupled binuclear complex that resembled oxidized 2 Fe ferredoxins, together with a small amount of high-spin Fe(II). EPR spectra recorded no signal at 77 0 K, but showed a slightly asymmetric signal centered at g=2.0 at 4.2 0 K, presumably due to the small amount of Fe(II) Fe(III) pairs. (auth.)

  16. Multi-photon Rabi oscillations in high spin paramagnetic impurity

    Bertaina, S; Groll, N; Chen, L; Chiorescu, I

    2011-01-01

    We report on multiple photon monochromatic quantum oscillations (Rabi oscillations) observed by pulsed EPR (Electron Paramagnetic Resonance) of Mn 2+ (S = 5/2) impurities in MgO. We find that when the microwave magnetic field is similar or large than the anisotropy splitting, the Rabi oscillations have a spectrum made of many frequencies not predicted by the S = l/2 Rabi model. We show that these new frequencies come from multiple photon coherent manipulation of the multi-level spin impurity. We develop a model based on the crystal field theory and the rotating frame approximation, describing the observed phenomenon with a very good agreement.

  17. Moessbauer studies on the paramagnetic porton of alkidirat meteorite

    Kamal, Huda Mohamed

    1995-11-01

    This work was performed on a sample from alkidirat meteorite which fell west of Sudan by means of Moessbauer effect spectrometer. results showed the absence of transition temperature from the paramagnetic state to the magnetic state in the temperature range from 300K down to 16K. Also, it was found that olivine and ortho pyroxene exist together in site M 1 , while clinothyroxene exists alone in site M 2 . Formula for the composition of ortho pyroxene in the sample were also obtained and they were in good agreement with previous studies. The disorder parameter was also calculated and it showed that the pyroxene present in the sample is well-ordered.(Author)

  18. Optical and paramagnetic properties of Ti in LiF

    Krystek, M.

    1982-01-01

    Titanium replaces substitutionally Li + at its lattice site in LiF. The resulting deep impurity must be understood as TiF 6 -cluster. The symmetry of this cluster is octahedral in the case of the unoccupied impurity. If the impurity will be occupied by an electron, a trigonal distortion of the cluster results, whereby the orbital degeneracy of the ground state will be liftet. Since the occupied impurity is paramagnetic, the symmetry reduction could be proved by ENDOR measurements. Using a calculated term diagram of the impurity inside the crystal a model is offered to explain the photoluminescence and the thermoluminescence of LiF:Ti. (orig./HP) [de

  19. Development of polarization magneto-optics of paramagnetic crystals

    Zapasskij, V.S.; Feofilov, P.P.

    1975-01-01

    The present status of the polarization magnetooptics of crystals containing paramagnetic ion impurities is reviewed. The paper discusses methods of measurement of circular magnetic anisotropy and results obtained in recent years in the field of conventional magnetooptical studies, e.g., magnetooptical activity in absorption spectra for intrinsic and impurity defects in crystals, luminescence magnetic circular polarization, anisotropy of magnetooptical activity in cubic crystals. The main emphasis is placed on new trends in polarization magnetooptics: studies of interactions of a spin system with a lattice, in particular, spin-lattice relaxation and spin memory effect, experiments in the double radiooptical resonance, studies of optical spin relaxation, nonlinear magnetooptical effects, etc

  20. Magnon Spin Hall Magnetoresistance of a Gapped Quantum Paramagnet

    Ulloa, Camilo; Duine, R. A.

    2018-04-01

    Motivated by recent experimental work, we consider spin transport between a normal metal and a gapped quantum paramagnet. We model the latter as the magnonic Mott-insulating phase of an easy-plane ferromagnetic insulator. We evaluate the spin current mediated by the interface exchange coupling between the ferromagnet and the adjacent normal metal. For the strongly interacting magnons that we consider, this spin current gives rise to a spin Hall magnetoresistance that strongly depends on the magnitude of the magnetic field, rather than its direction. This Letter may motivate electrical detection of the phases of quantum magnets and the incorporation of such materials into spintronic devices.

  1. Magnetic refrigeration apparatus with belt of ferro or paramagnetic material

    Barclay, John A.; Stewart, Walter F.; Henke, Michael D.; Kalash, Kenneth E.

    1987-01-01

    A magnetic refrigerator operating in the 12 to 77K range utilizes a belt which carries ferromagnetic or paramagnetic material and which is disposed in a loop which passes through the center of a solenoidal magnet to achieve cooling. The magnetic material carried by the belt, which can be blocks in frames of a linked belt, can be a mixture of substances with different Curie temperatures arranged such that the Curie temperatures progressively increase from one edge of the belt to the other. This magnetic refrigerator can be used to cool and liquefy hydrogen or other fluids.

  2. Retrospective dosimetry of nail by Electron Paramagnetic Resonance

    Giannoni, Ricardo A.; Rodrigues Junior, Orlando

    2015-01-01

    The purpose of this study is to characterize samples of human nails, subjected to irradiation of high doses through Technical Electron Paramagnetic Resonance (EPR). The goal is to establish a dose/response relationship in order to assess dose levels absorbed by individuals exposed in radiation accidents situations, retrospectively. Samples of human nails were irradiated with gamma radiation, and received a dose of 20 Gy. EPR measurements performed on samples before irradiation identified EPR signals associated with defects caused by the mechanical action of the sample collection. After irradiation other species of free radicals, associated with the action of gamma radiation, have been identified

  3. Size-dependent concentration of N0 paramagnetic centres in HPHT nanodiamonds

    Yavkin, Boris V; Mamin, Georgy V; Gafurov, Marat R.; Orlinskii, Sergei B.

    2015-01-01

    Size-calibrated commercial nanodiamonds synthesized by high-pressure high-temperature (HPHT) technique were studied by high-frequency W and conventional X band electron paramagnetic resonance (EPR) spectroscopy. The numbers of spins in the studied samples were estimated. The core-shell model of the HPHT nanodiamonds was proposed to explain the observed dependence of the concentration of the N0 paramagnetic centers. Two other observed paramagnetic centers are attributed to the two types of str...

  4. Fermionic spin liquid analysis of the paramagnetic state in volborthite

    Chern, Li Ern; Schaffer, Robert; Sorn, Sopheak; Kim, Yong Baek

    2017-10-01

    Recently, thermal Hall effect has been observed in the paramagnetic state of volborthite, which consists of distorted kagome layers with S =1 /2 local moments. Despite the appearance of magnetic order below 1 K , the response to external magnetic field and unusual properties of the paramagnetic state above 1 K suggest possible realization of exotic quantum phases. Motivated by these discoveries, we investigate possible spin liquid phases with fermionic spinon excitations in a nonsymmorphic version of the kagome lattice, which belongs to the two-dimensional crystallographic group p 2 g g . This nonsymmorphic structure is consistent with the spin model obtained in the density functional theory calculation. Using projective symmetry group analysis and fermionic parton mean field theory, we identify twelve distinct Z2 spin liquid states, four of which are found to have correspondence in the eight Schwinger boson spin liquid states we classified earlier. We focus on the four fermionic states with bosonic counterpart and find that the spectrum of their corresponding root U (1 ) states features spinon Fermi surface. The existence of spinon Fermi surface in candidate spin liquid states may offer a possible explanation of the finite thermal Hall conductivity observed in volborthite.

  5. Electron paramagnetic resonance in Cu-doped ZnO

    Buchheit, R.; Acosta-Humánez, F.; Almanza, O.

    2016-04-01

    In this work, ZnO and Cu-doped ZnO nanoparticles (Zn1-xCuxO, x = 3%), with a calcination temperature of 500∘C were synthesized using the sol-gel method. The particles were analyzed using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD) and electron paramagnetic resonance (EPR) at X-band, measurement in a temperature range from 90 K to room temperature. AAS confirmed a good correspondence between the experimental doping concentration and the theoretical value. XRD reveals the presence of ZnO phase in hexagonal wurtzite structure and a nanoparticle size for the samples synthesized. EPR spectroscopy shows the presence of point defects in both samples with g-values of g = 1.959 for shallow donors and g = 2.004 for ionized vacancies. It is important when these materials are required have been used as catalysts, as suggested that it is not necessary prepare them at higher temperature. A simulation of the Cu EPR signal using an anisotropic spin Hamiltonian was performed and showed good coincidence with the experimental spectra. It was shown that Cu2+ ions enter interstitial octahedral sites of orthorhombic symmetry in the wurtzite crystal structure. Temperature dependence of the EPR linewidth and signal intensity shows a paramagnetic behavior of the sample in the measurement range. A Néel temperature TN = 78 ± 19 K was determined.

  6. Paramagnetic ionic liquids for measurements of density using magnetic levitation.

    Bwambok, David K; Thuo, Martin M; Atkinson, Manza B J; Mirica, Katherine A; Shapiro, Nathan D; Whitesides, George M

    2013-09-03

    Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev.

  7. Intensities, broadening and narrowing parameters in the ν3 band of methane

    Es-sebbar, Et-touhami; Farooq, Aamir

    2014-01-01

    The P-branch of methane's ν3 band is probed to carry out an extensive study of the 2905-2908cm-1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001cm-1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.

  8. Observation of Conducting Structures in Detonation Nanodiamond Powder by Electron Paramagnetic Resonance

    Binh, Nguyen Thi Thanh; Dolmatov, V. Yu.; Lapchuk, N. M.

    2018-01-01

    We have used electron paramagnetic resonance (EPR) to study high-purity detonation nanodiamond (DND) powders at room temperature. In recording the EPR signal with g factor 2.00247 and line width 0.890 mT, with automatic frequency control locking the frequency of the microwave generator (klystron) to the frequency of the experimental cavity, we observed a change in the shape of the EPR signal from the DND powder due to formation of an anisotropic electrically conducting structure in the powder. The electrical conductivity of the DND sample is apparent in the Dysonian EPR lineshape (strongly asymmetric signal with g factor 2.00146 and line width 0.281 mT) together with an abrupt shift of the baseline at the time of resonant absorption, and in the decrease in the cavity Q due to nonresonant microwave absorption. The observed effect can be explained by transition of the DND powder from a dielectric state to a state with metallic conductivity, due to spin ordering in a preferred direction.

  9. Multi-frequency EDMR studies of light-activated paramagnetic centers in μc-Si:H thin-film solar cells

    Meier, Christoph

    2014-01-01

    This thesis presents a comprehensive study of paramagnetic centers in fully-processed microcrystalline silicon (μc-Si:H) thin-film solar cells. The heterogeneous material gives rise to a complex band structure with deep defects in the middle of the energy band gap as well as localized states close to the energy band edges. They can act as recombination centers and traps and, thereby, influence the charge transport of photogenerated charge carriers. Thus, they diminish the performance of the cell. To reduce the disadvantageous influence of the defect states on the cell efficiency, a detailed understanding of the charge transport processes via these states is necessary. In this work, light-activated paramagnetic centers are studied with electrically detected magnetic resonance (EDMR) at various microwave frequencies. This technique combines electron paramagnetic resonance spectroscopy (EPR) with the photocurrent measurement in the solar cell, thus, delivering information about the transport processes and magnetic parameters of the involved defect states. Multi-frequency EDMR at low temperatures reveals four paramagnetic states in μc-Si:H. Dangling bond (db) defects and holes in valence band tail (h) states are located in the disordered phase, whereas so-called CE and V states originate from the crystalline phase. The multi-frequency approach allows for a separation of field-dependent and -independent line widths. All EDMR signals are affected by line broadening due to spin-spin interaction, which could be used to estimate mean inter-spin distances of around ∼ 0.5 nm for the V center and of ∼ 1-2 nm for the remaining centers. Based on the strong spin-spin coupling and on transient nutation experiments the V signal could be correlated with a vacancy site in its excited triplet state. From the particular properties of the CE line it was concluded that the corresponding states are located in inversion layers and potential wells close to the conduction band of

  10. Trispyrazolylborate Complexes: An Advanced Synthesis Experiment Using Paramagnetic NMR, Variable-Temperature NMR, and EPR Spectroscopies

    Abell, Timothy N.; McCarrick, Robert M.; Bretz, Stacey Lowery; Tierney, David L.

    2017-01-01

    A structured inquiry experiment for inorganic synthesis has been developed to introduce undergraduate students to advanced spectroscopic techniques including paramagnetic nuclear magnetic resonance and electron paramagnetic resonance. Students synthesize multiple complexes with unknown first row transition metals and identify the unknown metals by…

  11. Magnetic nanoparticle imaging using multiple electron paramagnetic resonance activation sequences

    Coene, A.; Dupré, L.; Crevecoeur, G.

    2015-01-01

    Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a non-invasive way. Electron Paramagnetic Resonance (EPR) is a promising and sensitive measurement technique for recovering these distributions. In the conventional approach, EPR is applied with a homogeneous magnetic field. In this paper, we employ different heterogeneous magnetic fields that allow to stabilize the solution of the associated inverse problem and to obtain localized spatial information. A comparison is made between the two approaches and our novel adaptation shows an average increase in reconstruction quality by 5% and is 12 times more robust towards noise. Furthermore, our approach allows to speed up the EPR measurements while still obtaining reconstructions with an improved accuracy and noise robustness compared to homogeneous EPR

  12. Enhanced Wireless Power Transmission Using Strong Paramagnetic Response.

    Ahn, Dukju; Kiani, Mehdi; Ghovanloo, Maysam

    2014-03-01

    A method of quasi-static magnetic resonant coupling has been presented for improving the power transmission efficiency (PTE) in near-field wireless power transmission, which improves upon the state of the art. The traditional source resonator on the transmitter side is equipped with an additional resonator with a resonance frequency that is tuned substantially higher than the magnetic field excitation frequency. This additional resonator enhances the magnetic dipole moment and the effective permeability of the power transmitter, owing to a phenomenon known as the strong paramagnetic response. Both theoretical calculations and experimental results show increased PTE due to amplification of the effective permeability. In measurements, the PTE was improved from 57.8% to 64.2% at the nominal distance of 15 cm when the effective permeability was 2.6. The power delivered to load was also improved significantly, with the same 10 V excitation voltage, from 0.38 to 5.26 W.

  13. Electron paramagnetic resonance of the ns1 centers in crystals

    Nistor, S.V.; Ursu, I.

    1993-05-01

    The results of the EPR studies concerning the paramagnetic centers with ns 1 (N=n>2) outer electronic configuration contained in crystals are reviewed. Such centers, with 2 S 1/2 ground state, are produced by electron trapping at impurities of the IB and IIB group or by hole trapping at impurities of the IIIB and IV group of elements. The production and structural properties of such centers consisting of ns 1 ions (atoms) at various sites in the crystal lattice with different configurations of neighbouring defects are discussed in connection with their EPR characteristics. Tables containing the spin Hamiltonian parameters of all ns 1 centers reported in the literature until the end of year 1992 are given. (author). 146 refs, 14 tabs

  14. Modified Mason number for charged paramagnetic colloidal suspensions

    Du, Di; Hilou, Elaa; Biswal, Sibani Lisa

    2016-06-01

    The dynamics of magnetorheological fluids have typically been described by the Mason number, a governing parameter defined as the ratio between viscous and magnetic forces in the fluid. For most experimental suspensions of magnetic particles, surface forces, such as steric and electrostatic interactions, can significantly influence the dynamics. Here we propose a theory of a modified Mason number that accounts for surface forces and show that this modified Mason number is a function of interparticle distance. We demonstrate that this modified Mason number is accurate in describing the dynamics of a rotating pair of paramagnetic colloids of identical or mismatched sizes in either high or low salt solutions. The modified Mason number is confirmed to be pseudoconstant for particle pairs and particle chains undergoing a stable-metastable transition during rotation. The interparticle distance term can be calculated using theory or can be measured experimentally. This modified Mason number is more applicable to magnetorheological systems where surface forces are not negligible.

  15. Biophysical dosimetry using electron paramagnetic resonance in human tooth

    Khan, R.F.H.; Boreham, D.R.; Rink, W.J.

    2002-01-01

    Accidental dosimetry utilizing radiation induced paramagnetic species in biophysical tissues like teeth is a technique; that can measure the amount of radiation exposure to an individual. The major problem in implementing this technique at low doses is the presence of native organic signal, and various other artifacts produced as a result of sample processing. After a series of experimental trials, we developed an optimum set of rules, which uses high temperature ultrasonic treatment of enamel in KOH, multiple sample rotation during in-cavity measurement of natural and calibrated added irradiations, and dose construction using a backward extrapolation method. By using this we report the successful dose reconstruction in a few of our laboratory samples in 100 mGy range (76.29 ± 30.14) mGy with reasonably low uncertainty. Keywords: biophysical dosimetry, human tooth enamel, low dose measurements, accidental dosimetry (author)

  16. The paramagnetic properties of ferromagnetic mixed-spin chain system

    Hu, Ai-Yuan; Wu, Zhi-Min; Cui, Yu-Ting; Qin, Guo-Ping

    2015-01-01

    The double-time Green's function method is used to investigate the paramagnetic properties of ferromagnetic mixed-spin chain system within the random-phase approximation and Anderson–Callen's decoupling approximation. The analytic expressions of the transverse susceptibility, longitudinal susceptibility and correlation length are obtained under transverse and longitudinal magnetic field. Using the analytic expressions of the transverse and longitudinal susceptibility to fit the experimental results, our results well agree with experimental data and the results from the high temperature series expansion within a simple Padé approximation. - Highlights: • We investigate the magnetic properties of a ferromagnetic mixed-spin chain system. • We use the double-time temperature-dependent Green's function technique. • Different single-ion anisotropy values for different spin values are considered. • Our results agree with experimental data and the results from the other theoretical methods

  17. Radiation silver paramagnetic centers in a beta-alumina crystal

    Badalyan, A.G.; Zhitnikov, R.A.

    1985-01-01

    Silver paramagnetic centers in a β-alumina crystal, formed after X-ray radiation at 77 K, are investigated by the EPR method. Silver enters the β-alumina crystal, substituting sodium and potassium ions in a mirror plane. Crystals with substitution from 0.1 to 100% of alkali metal ions by Ag + ions are investigated. Silver atomic centers (Ag 0 -centers), formed by electron capture with the Ag + ion, are firstly detected and investigated in the β-alumina. Hole Ag 2+ -centers are investigated and detected in crystals with high concentration of Ag + . By studying the orientation dependence of a g-factor it is established that hole capture by the Ag + ion is accompanied by Ag 2+ ion displacement from the position, Ag + being primarity taken up (Beavers-Roth or anti- Beavers-Roth) to the position between two oxygen ions in the mirror plane

  18. Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    2006-01-01

    The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...... into account a number of individual compartments. The signal dephasing is simulated in a semianalytical way by embedding Monte Carlo simulations in the framework of analytical theory. This approach yields a tool for fast, realistic simulation of the change in the transverse relaxation. The results indicate...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size...

  19. Moessbauer studies on the paramagnetic porton of alkidirat meteorite

    Kamal, Huda Mohamed [Department of Physics, Faculty of Science, University of Khartoum, Khartoum (Sudan)

    1995-11-01

    This work was performed on a sample from alkidirat meteorite which fell west of Sudan by means of Moessbauer effect spectrometer. results showed the absence of transition temperature from the paramagnetic state to the magnetic state in the temperature range from 300K down to 16K. Also, it was found that olivine and ortho pyroxene exist together in site M{sup 1}, while clinothyroxene exists alone in site M{sup 2}. Formula for the composition of ortho pyroxene in the sample were also obtained and they were in good agreement with previous studies. The disorder parameter was also calculated and it showed that the pyroxene present in the sample is well-ordered.(Author) 37 refs. , 2 tabs. , 19 figs.

  20. Thermodynamically consistent mesoscopic model of the ferro/paramagnetic transition

    Benešová, Barbora; Kružík, Martin; Roubíček, Tomáš

    2013-01-01

    Roč. 64, Č. 1 (2013), s. 1-28 ISSN 0044-2275 R&D Projects: GA AV ČR IAA100750802; GA ČR GA106/09/1573; GA ČR GAP201/10/0357 Grant - others:GA ČR(CZ) GA106/08/1397; GA MŠk(CZ) LC06052 Program:GA; LC Institutional support: RVO:67985556 Keywords : ferro-para-magnetism * evolution * thermodynamics Subject RIV: BA - General Mathematics; BA - General Mathematics (UT-L) Impact factor: 1.214, year: 2013 http://library.utia.cas.cz/separaty/2012/MTR/kruzik-thermodynamically consistent mesoscopic model of the ferro-paramagnetic transition.pdf

  1. Large-amplitude and narrow-band vibration phenomenon of a foursquare fix-supported flexible plate in a rigid narrow channel

    Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Lu Daogang, E-mail: ludaogang@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Li Yang, E-mail: qinxiuyi@sina.com [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Zhang Pan, E-mail: zhangpan@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Niu Fenglei, E-mail: niufenglei@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

    2011-08-15

    Highlights: > FIV of a foursquare fix-supported flexible plate exposed to axial flow was studied. > Special designed test section and advanced measuring equipments were adopted. > The narrow-band vibration phenomenon with large amplitude was observed. > Line of plate's vibration amplitude and flow rate was investigated. > The phenomenon and the measurement error were analyzed. - Abstract: An experiment was performed to analyze the flow-induced vibration behavior of a foursquare fix-supported flexible plate exposed to the axial flow within a rigid narrow channel. The large-amplitude and narrow-band vibration phenomenon was observed in the experiment when the flow velocity varied with the range of 0-5 m/s. The occurring condition and some characteristics of the large-amplitude and narrow-band vibrations were investigated.

  2. Point defects in crystalline zircon (zirconium silicate), ZrSiO4: electron paramagnetic resonance studies

    Tennant, W. C.; Claridge, R. F. C.; Walsby, C. J.; Lees, N. S.

    This article outlines the present state of knowledge of paramagnetic defects in crystalline zircon as obtained mainly, but not exclusively, from electron paramagnetic resonance (EPR) studies in crystalline zircon (zirconium silicate, ZrSiO4). The emphasis is on single-crystal studies where, in principle, unambiguous analysis is possible. Firstly, the crystallography of zircon is presented. Secondly, the relationships between available crystal-site symmetries and the symmetries of observed paramagnetic species in zircon, and how these observations lead to unambiguous assignments of point-group symmetries for particular paramagnetic species are detailed. Next, spin-Hamiltonian (SH) analysis is discussed with emphasis on the symmetry relationships that necessarily exist amongst the Laue classes of the crystal sites in zircon, the paramagnetic species occupying those sites and the SH itself. The final sections of the article then survey the results of EPR studies on zircon over the period 1960-2002.

  3. Device Physics of Narrow Gap Semiconductors

    Chu, Junhao

    2010-01-01

    Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only the semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The last chapter applies the understanding of device physics to photoconductive detectors, photovoltaic infrared detector...

  4. Electron paramagnetic resonance study of ternary Cu compounds ...

    field modulation, and ∼19mW of microwave power. .... using EasySpin,38 a program working under Matlab39 as ... simulations obtained as explained in the text. σ denote the qua- ..... the exchange narrowing process is the collapse of reso-.

  5. Narrow-front loop migration in a population of the common cuckoo Cuculus canorus, as revealed by satellite telemetry

    Willemoes, Mikkel; Strandberg, Roine; Klaassen, Raymond H. G.; Tottrup, Anders P.; Vardanis, Yannis; Howey, Paul W.; Thorup, Kasper; Wikelski, Martin; Alerstam, Thomas

    2014-01-01

    Narrow migration corridors known in diurnal, social migrants such as raptors, storks and geese are thought to be caused by topographical leading line effects in combination with learning detailed routes across generations. Here, we document narrow-front migration in a nocturnal, solitary migrant,

  6. Novel structural flexibility identification in narrow frequency bands

    Zhang, J; Moon, F L

    2012-01-01

    A ‘Sub-PolyMAX’ method is proposed in this paper not only for estimating modal parameters, but also for identifying structural flexibility by processing the impact test data in narrow frequency bands. The traditional PolyMAX method obtains denominator polynomial coefficients by minimizing the least square (LS) errors of frequency response function (FRF) estimates over the whole frequency range, but FRF peaks in different structural modes may have different levels of magnitude, which leads to the modal parameters identified for the modes with small FRF peaks being inaccurate. In contrast, the proposed Sub-PolyMAX method implements the LS solver in each subspace of the whole frequency range separately; thus the results identified from a narrow frequency band are not affected by FRF data in other frequency bands. In performing structural identification in narrow frequency bands, not in the whole frequency space, the proposed method has the following merits: (1) it produces accurate modal parameters, even for the modes with very small FRF peaks; (2) it significantly reduces computation cost by reducing the number of frequency lines and the model order in each LS implementation; (3) it accurately identifies structural flexibility from impact test data, from which structural deflection under any static load can be predicted. Numerical and laboratory examples are investigated to verify the effectiveness of the proposed method. (paper)

  7. Luminescence and paramagnetic centers in antigorite and Lizardite, two members of serpentine group: a comparative study

    Rocca, Rene Rojas

    2008-01-01

    In this work, we are describing crystals luminescent properties of Antigorite (monoclinic, Mg 3-x [Si 2 O 5 ](OH) 4-2x ) and Lizardite (triclinic, Mg 3 [(Si,Fe) 2 O 5 ](OH) 4 ). They were studied simultaneously applying several techniques, like: Thermoluminescence (TL), Optical Absorption (OA), Electron Paramagnetic Resonance (EPR), X-rays diffraction and Inductively Coupled Plasma (ICP). Using cold pressed elements and heating the samples to 350 deg C for TL measurements, we can observe reproductive peaks. Antigorita show well differentiated peaks and intensities, but Lizardite show overlapped and similar intensity peaks. Peaks of both samples occur around 150, 200, 250, 300 deg C, and all them grow linearly up to 2 kGy, saturating for high doses, except 250 deg C peak which continue growing with dose until 172 kGy. TL peaks trap parameters and lifetimes were calculated, the curves were fitted using the GCD method with second order kinetic. The EPR spectrum shows 6 hyperfine structure lines, characteristic of Manganese, besides lines due to Iron. It was possible also to observe two super hyperfine Mn 2+ lines. The EPR signal does not change with irradiation dose in both crystals. These impurities were also detected in the ICP analysis. The OA spectrum of lizardite show bands from 370 to 470 nm which were not observed in antigorite samples probably related to Fe 3+ and Mn 2+ . In the infrared region several (OA) bands of Mg-OH combination were observed. Again the OA spectrum of these crystals does not change with irradiation dose. We conclude that TL samples peaks around 150, 200, 250, 300 deg C can be used for radiation ionizing dosimetry (y-rays and B- particle) for intermediate and high doses. (author)

  8. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces.

    Sidabras, Jason W; Varanasi, Shiv K; Mett, Richard R; Swarts, Steven G; Swartz, Harold M; Hyde, James S

    2014-10-01

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg(2+) doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  9. A microwave resonator for limiting depth sensitivity for electron paramagnetic resonance spectroscopy of surfaces

    Sidabras, Jason W.; Varanasi, Shiv K.; Hyde, James S. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Mett, Richard R. [Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin 53211 (United States); Department of Physics and Chemistry, Milwaukee School of Engineering, Milwaukee, Wisconsin 53202 (United States); Swarts, Steven G. [Department of Radiation Oncology, University of Florida, Gainesville, Florida, 32610 (United States); Swartz, Harold M. [Department of Radiology, Geisel Medical School at Dartmouth, Hanover, New Hampshire 03755 (United States)

    2014-10-15

    A microwave Surface Resonator Array (SRA) structure is described for use in Electron Paramagnetic Resonance (EPR) spectroscopy. The SRA has a series of anti-parallel transmission line modes that provides a region of sensitivity equal to the cross-sectional area times its depth sensitivity, which is approximately half the distance between the transmission line centers. It is shown that the quarter-wave twin-lead transmission line can be a useful element for design of microwave resonators at frequencies as high as 10 GHz. The SRA geometry is presented as a novel resonator for use in surface spectroscopy where the region of interest is either surrounded by lossy material, or the spectroscopist wishes to minimize signal from surrounding materials. One such application is in vivo spectroscopy of human finger-nails at X-band (9.5 GHz) to measure ionizing radiation dosages. In order to reduce losses associated with tissues beneath the nail that yield no EPR signal, the SRA structure is designed to limit depth sensitivity to the thickness of the fingernail. Another application, due to the resonator geometry and limited depth penetration, is surface spectroscopy in coating or material science. To test this application, a spectrum of 1.44 μM of Mg{sup 2+} doped polystyrene 1.1 mm thick on an aluminum surface is obtained. Modeling, design, and simulations were performed using Wolfram Mathematica (Champaign, IL; v. 9.0) and Ansys High Frequency Structure Simulator (HFSS; Canonsburg, PA; v. 15.0). A micro-strip coupling circuit is designed to suppress unwanted modes and provide a balanced impedance transformation to a 50 Ω coaxial input. Agreement between simulated and experimental results is shown.

  10. Electron paramagnetic resonance imaging of tumor hypoxia: enhanced spatial and temporal resolution for in vivo pO2 determination.

    Matsumoto, Ken-ichiro; Subramanian, Sankaran; Devasahayam, Nallathamby; Aravalluvan, Thirumaran; Murugesan, Ramachandran; Cook, John A; Mitchell, James B; Krishna, Murali C

    2006-05-01

    The time-domain (TD) mode of electron paramagnetic resonance (EPR) data collection offers a means of estimating the concentration of a paramagnetic probe and the oxygen-dependent linewidth (LW) to generate pO2 maps with minimal errors. A methodology for noninvasive pO2 imaging based on the application of TD-EPR using oxygen-induced LW broadening of a triarylmethyl (TAM)-based radical is presented. The decay of pixel intensities in an image is used to estimate T2*, which is inversely proportional to pO2. Factors affecting T2* in each pixel are critically analyzed to extract the contribution of dissolved oxygen to EPR line-broadening. Suitable experimental and image-processing parameters were obtained to produce pO2 maps with minimal artifacts. Image artifacts were also minimized with the use of a novel data collection strategy using multiple gradients. Results from a phantom and in vivo imaging of tumor-bearing mice validated this novel method of noninvasive oximetry. The current imaging protocols achieve a spatial resolution of approximately 1.0 mm and a temporal resolution of approximately 9 s for 2D pO2 mapping, with a reliable oxygen resolution of approximately 1 mmHg (0.12% oxygen in gas phase). This work demonstrates that in vivo oximetry can be performed with good sensitivity, accuracy, and high spatial and temporal resolution.

  11. High-resolution mapping of 1D and 2D dose distributions using X-band electron paramagnetic resonance imaging

    Kolbun, N.; Lund, E.; Adolfsson, E.; Gustafsson, H.

    2014-01-01

    Electron paramagnetic resonance imaging (EPRI) was performed to visualise 2D dose distributions of homogeneously irradiated potassium dithionate tablets and to demonstrate determination of 1D dose profiles along the height of the tablets. Mathematical correction was applied for each relative dose profile in order to take into account the inhomogeneous response of the resonator using X-band EPRI. The dose profiles are presented with the spatial resolution of 0.6 mm from the acquired 2D images; this value is limited by pixel size, and 1D dose profiles from 1D imaging with spatial resolution of 0.3 mm limited by the intrinsic line-width of potassium dithionate. In this paper, dose profiles from 2D reconstructed electron paramagnetic resonance (EPR) images using the Xepr software package by Bruker are focussed. The conclusion is that using potassium dithionate, the resolution 0.3 mm is sufficient for mapping steep dose gradients if the dosemeters are covering only ±2 mm around the centre of the resonator. (authors)

  12. EPR and optical absorption studies of paramagnetic molecular ion (VO2+) in Lithium Sodium Acid Phthalate single crystal

    Subbulakshmi, N.; Kumar, M. Saravana; Sheela, K. Juliet; Krishnan, S. Radha; Shanmugam, V. M.; Subramanian, P.

    2017-12-01

    Electron Paramagnetic Resonance (EPR) spectroscopic studies of VO2+ ions as paramagnetic impurity in Lithium Sodium Acid Phthalate (LiNaP) single crystal have been done at room temperature on X-Band microwave frequency. The lattice parameter values are obtained for the chosen system from Single crystal X-ray diffraction study. Among the number of hyperfine lines in the EPR spectra only two sets are reported from EPR data. The principal values of g and A tensors are evaluated for the two different VO2+ sites I and II. They possess the crystalline field around the VO2+ as orthorhombic. Site II VO2+ ion is identified as substitutional in place of Na1 location and the other site I is identified as interstitial location. For both sites in LiNaP, VO2+ are identified in octahedral coordination with tetragonal distortion as seen from the spin Hamiltonian parameter values. The ground state of vanadyl ion in the LiNaP single crystal is dxy. Using optical absorption data the octahedral and tetragonal parameters are calculated. By correlating EPR and optical data, the molecular orbital bonding parameters have been discussed for both sites.

  13. Advantages of paramagnetic chemical exchange saturation transfer (CEST) complexes having slow to intermediate water exchange properties as responsive MRI agents.

    Soesbe, Todd C; Wu, Yunkou; Dean Sherry, A

    2013-07-01

    Paramagnetic chemical exchange saturation transfer (PARACEST) complexes are exogenous contrast agents that have great potential to further extend the functional and molecular imaging capabilities of magnetic resonance. As a result of the presence of a central paramagnetic lanthanide ion (Ln(3+) ≠ La(3+) , Gd(3+) , Lu(3+) ) within the chelate, the resonance frequencies of exchangeable protons bound to the PARACEST agent are shifted far away from the bulk water frequency. This large chemical shift, combined with an extreme sensitivity to the chemical exchange rate, make PARACEST agents ideally suited for the reporting of significant biological metrics, such as temperature, pH and the presence of metabolites. In addition, the ability to turn PARACEST agents 'off' and 'on' using a frequency-selective saturation pulse gives them a distinct advantage over Gd(3+) -based contrast agents. A current challenge for PARACEST research is the translation of the promising in vitro results into in vivo systems. This short review article first describes the basic theory behind PARACEST contrast agents, their benefits over other contrast agents and their applications to MRI. It then describes some of the recent PARACEST research results: specifically, pH measurements using water molecule exchange rate modulation, T2 exchange contrast caused by water molecule exchange, the use of ultrashort TEs (TE < 10 µs) to overcome T2 exchange line broadening and the potential application of T2 exchange as a new contrast mechanism for MRI. Copyright © 2012 John Wiley & Sons, Ltd.

  14. A renormalized -group attempt to obtain the exact transition line of the square - lattice bond - dilute Ising model

    Tsallis, C.; Levy, S.V.F.

    1979-05-01

    Two different renormalization-group approaches are used to determine approximate solutions for the paramagnetic-ferromagnetic transition line of the square-lattice bond-dilute first-neighbour-interaction Ising model. (Author) [pt

  15. Electron paramagnetic resonance of V4+ in the lanthanum and cerium orthophosphates

    Lima, J.C. de.

    1983-11-01

    The Electron Paramagnetic Resonance (EPR) spectrum of V 4+ was investigated in polycrystalline samples of lanthanum orthophosphate (LaPO 4 ) and cerium orthophosphate (CePO 4 ) doped with 0.2 wt % vanadium pentoxide (V 2 O 5 ). Measurements were performed at room temperature and 9.5 GHz. In LaPO 4 , two non-equivalent axial sites were inferred from the EPR spectra. The most stable of these two sites is probably substitutional. In CePO 4 , a single axial spectrum was observed. It was attributed to V 4+ in substitutional sites. A central, wide line was also seen; it was attributed to ferromagnetic clusters of vanadium ions. Photoacoustic absorption spectra were also recorded for the two compounds. The EPR and photoacoustic absorption data, when analyzed using the molecular orbital theory, show that for both lanthanum orthophosphate and cerium orthophosphate the ground orbital (d sub(x) 2 sub(-y) 2) of the unpainred electron is purely ionic, while the excited orbitals d sub(xy) and d sub(xz,yz) are partly covalent. The degree of covalency is higher for the d sub(xy) orbital. Finally, it should be pointed out that part of the theory used for the interpretation of the EPR and photoacoustic absorption spectra (study of the ligand field splitting of a d orbital in a site of distorted capped antiprism structure) was developed by the author in the present work and is therefore an original contribution. (Author) [pt

  16. Optically trapped atomic resonant devices for narrow linewidth spectral imaging

    Qian, Lipeng

    This thesis focuses on the development of atomic resonant devices for spectroscopic applications. The primary emphasis is on the imaging properties of optically thick atomic resonant fluorescent filters and their applications. In addition, this thesis presents a new concept for producing very narrow linewidth light as from an atomic vapor lamp pumped by a nanosecond pulse system. This research was motivated by application for missile warning system, and presents an innovative approach to a wide angle, ultra narrow linewidth imaging filter using a potassium vapor cell. The approach is to image onto and collect the fluorescent photons emitted from the surface of an optically thick potassium vapor cell, generating a 2 GHz pass-band imaging filter. This linewidth is narrow enough to fall within a Fraunhefer dark zone in the solar spectrum, thus make the detection solar blind. Experiments are conducted to measure the absorption line shape of the potassium resonant filter, the quantum efficiency of the fluorescent behavior, and the resolution of the fluorescent image. Fluorescent images with different spatial frequency components are analyzed by using a discrete Fourier transform, and the imaging capability of the fluorescent filter is described by its Modulation Transfer Function. For the detection of radiation that is spectrally broader than the linewidth of the potassium imaging filter, the fluorescent image is seen to be blurred by diffuse fluorescence from the slightly off resonant photons. To correct this, an ultra-thin potassium imaging filter is developed and characterized. The imaging property of the ultra-thin potassium imaging cell is tested with a potassium seeded flame, yielding a resolution image of ˜ 20 lines per mm. The physics behind the atomic resonant fluorescent filter is radiation trapping. The diffusion process of the resonant photons trapped in the atomic vapor is theoretically described in this thesis. A Monte Carlo method is used to simulate the

  17. Nature of the magnetic susceptibility of dysprosium. Paramagnetic susceptibility of dysprosium - yttrium alloys

    Demidov, V.G.; Levitin, R.Z.; Chistyakov, O.D.

    1976-01-01

    The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature

  18. Ferro-paramagnetic coupled resonant modes in GdEuCuO4

    Fainstein, A.; Tovar, M.

    1990-01-01

    Two paramagnetic resonances were observed in compound GdEuCuO 4 : one was originated in trivalent gadolinium paramagnetism, while the other is associated to a weak ferromagnetic mode in Cu-O planes. In this work, experimental results are presented that show an anisotropy and a strongly anomalous temperature dependence of Gd 3+ . A theoretical model was introduced which explains the data in terms of coupled ferro-paramagnetic resonant modes originated in spin exchange coupling of Cu and Gd. (Author). 9 refs., 4 figs

  19. Size-dependent concentration of N0 paramagnetic centres in HPHT nanodiamonds

    B.V. Yavkin, G.V. Mamin, M.R. Gafurov, S.B. Orlinskii

    2015-12-01

    Full Text Available Size-calibrated commercial nanodiamonds synthesized by high-pressure high-temperature (HPHT technique were studied by high-frequency W- and conventional X-band electron paramagnetic resonance (EPR spectroscopy. The numbers of spins in the studied samples were estimated. The core-shell model of the HPHT nanodiamonds was proposed to explain the observed dependence of the concentration of the N0 paramagnetic centers. Two other observed paramagnetic centers are attributed to the two types of structures in the nanodiamond shell.

  20. Study of radiation-induced paramagnetic centers in quartz and its possible use in radiation dosimetry

    Mansour, A.M.E.

    2008-01-01

    A new EPR dosimetry system has been developed based on the radiation-formed stable paramagnetic centers in quartz. The first part of the thesis includes the preparation of quartz rods (diameter = 3 mm, length = 10 mm) where quartz powder was mixed with molten mixture of paraffin wax and ethylene vinyl acetate copolymer (EVA). The binding-mixture EVA / paraffin do not present interference or noise in the EPR signal before or after irradiation to high doses. The quartz rods were prepared by different concentrations (5, 10, 20, 30 and 50 %). The rods (30 %) show good mechanical properties for safe and multi-use handling. The second part is concerned with studying the dosimetric characteristics of gamma irradiation sensitive rods where the radiation-formed stable free radicals (E-center, peroxy radical and non-bridging oxygen hole center) which analyzed by using electron paramagnetic resonance (EPR) spectrometer. Unirradiated rods have no EPR signals. The useful dose range of these rods was found to range from 0.1 to 80 kGy depending on concentration of quartz powder, indicating their suitability for low and high dose gamma radiation applications. Also it was found that quartz rod exhibits a linear dose response in the dose regions 0.1-2.34 and 2.34-26 kGy at optimum EPR parameters. The dosimeter response was assessed using the peak-to-peak amplitude of the first-derivatives EPR spectrum. Its EPR signal was found unchanged in shape with different doses and different concentrations. A signal line spectrum attributed to the E-center was observed after irradiation, and this radical is insensitive to temperature, light independence as well as it have a very low decay (4.768 % per year). The overall uncertainty for quartz rod dosimeters at 2σ (σ is standard deviation) was found to be 3.8436 %. The dosimetric parameters, e. g. dose response, effect of temperature during irradiation on response as well as pre- and post-irradiation stability at different storage conditions

  1. Highly Tunable Narrow Bandpass MEMS Filter

    Hafiz, Md Abdullah Al

    2017-07-07

    We demonstrate a proof-of-concept highly tunable narrow bandpass filter based on electrothermally and electrostatically actuated microelectromechanical-system (MEMS) resonators. The device consists of two mechanically uncoupled clamped-clamped arch resonators, designed such that their resonance frequencies are independently tuned to obtain the desired narrow passband. Through the electrothermal and electrostatic actuation, the stiffness of the structures is highly tunable. We experimentally demonstrate significant percentage tuning (~125%) of the filter center frequency by varying the applied electrothermal voltages to the resonating structures, while maintaining a narrow passband of 550 ± 50 Hz, a stopband rejection of >17 dB, and a passband ripple ≤ 2.5 dB. An analytical model based on the Euler-Bernoulli beam theory is used to confirm the behavior of the filter, and the origin of the high tunability using electrothermal actuation is discussed.

  2. Thermophysical properties of paramagnetic Fe from first principles

    Ehteshami, Hossein; Korzhavyi, Pavel A.

    2017-12-01

    A computationally efficient, yet general, free-energy modeling scheme is developed based on first-principles calculations. Finite-temperature disorder associated with the fast (electronic and magnetic) degrees of freedom is directly included in the electronic structure calculations, whereas the vibrational free energy is evaluated by a proposed model that uses elastic constants to calculate average sound velocity of the quasiharmonic Debye model. The proposed scheme is tested by calculating the lattice parameter, heat capacity, and single-crystal elastic constants of α -, γ -, and δ -iron as functions of temperature in the range 1000-1800 K. The calculations accurately reproduce the well-established experimental data on thermal expansion and heat capacity of γ - and δ -iron. Electronic and magnetic excitations are shown to account for about 20% of the heat capacity for the two phases. Nonphonon contributions to thermal expansion are 12% and 10% for α - and δ -Fe and about 30% for γ -Fe. The elastic properties predicted by the model are in good agreement with those obtained in previous theoretical treatments of paramagnetic phases of iron, as well as with the bulk moduli derived from isothermal compressibility measurements [N. Tsujino et al., Earth Planet. Sci. Lett. 375, 244 (2013), 10.1016/j.epsl.2013.05.040]. Less agreement is found between theoretically calculated and experimentally derived single-crystal elastic constants of γ - and δ -iron.

  3. Effects of water on fingernail electron paramagnetic resonance dosimetry.

    Zhang, Tengda; Zhao, Zhixin; Zhang, Haiying; Zhai, Hezheng; Ruan, Shuzhou; Jiao, Ling; Zhang, Wenyi

    2016-09-01

    Electron paramagnetic resonance (EPR) is a promising biodosimetric method, and fingernails are sensitive biomaterials to ionizing radiation. Therefore, kinetic energy released per unit mass (kerma) can be estimated by measuring the level of free radicals within fingernails, using EPR. However, to date this dosimetry has been deficient and insufficiently accurate. In the sampling processes and measurements, water plays a significant role. This paper discusses many effects of water on fingernail EPR dosimetry, including disturbance to EPR measurements and two different effects on the production of free radicals. Water that is unable to contact free radicals can promote the production of free radicals due to indirect ionizing effects. Therefore, varying water content within fingernails can lead to varying growth rates in the free radical concentration after irradiation-these two variables have a linear relationship, with a slope of 1.8143. Thus, EPR dosimetry needs to be adjusted according to the water content of the fingernails of an individual. When the free radicals are exposed to water, the eliminating effect will appear. Therefore, soaking fingernail pieces in water before irradiation, as many researchers have previously done, can cause estimation errors. In addition, nails need to be dehydrated before making accurately quantitative EPR measurements. © The Author 2016. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  4. Using an electron paramagnetic resonance method for testing motor oils

    Krais, S; Tkac, T

    1982-01-01

    Using an ER-9 spectrometer from the Karl Zeiss company, the relative effectiveness is studied of antioxidation additives. Motor oils of the E group, M6AD, 465, M6AD, 466, M6AD 467, 15 W/40, S-3/2 M/4, R-950, which contain the antioxidation additive were tested in Petter AV-1 motors at a temperature of 50 degrees for 120 hours and Petter AVB at a temperature of 90 degrees for 53 hours. To measure the concentration of free radicals of the antioxidation additives one part of 2,2-diphenyl-1-picrylhydrazine (I), which forms stable dimagnetic products with the radicals of the antioxidation additives was introduced into each three parts of the oil. The reduction in the intensity of the signal of I was the measure of the radical concentration. The spectrum was taken for 1 to 2 minutes. The graphs of the dependence of the electron paramagnetic resonance on the test time and the concentration of I are built. The beginning and end of the induction period of oxidation of the oils and the change in the hourly activity of the PP was recorded.

  5. Spin dynamics of EuS in the paramagnetic phase

    Chaudhury, R.; Shastry, B.S.

    1988-07-01

    The spin dynamics of the semiclassical Heisenberg model on the fcc lattice, with ferromagnetic interaction in the first neighbour shell, anti-ferromagnetic interaction in the second neighbour shell and which undergoes a ferromagnetic transition, is studied in the paramagnetic phase at the temperature 1.1 T c using the Monte-Carlo molecular dynamics technique. The important quantities calculated are the dynamic structure function S(q-vector,ω) and the spin auto-correlation function i (O)·S-vector i (t)>. Our results for S(q-vector,ω) show the existence of purely diffusive modes in the low q regime. For q-vector close to the zone boundary, our calculated S(q-vector,ω) shows multi-peaked structure, signifying damped propagating modes. This result disagrees with the theoretical predictions of Young and Shastry and also of Lindgard. Our results for S(q-vector,ω) in the entire q-vector-space are in good qualitative and quantitative agreement with the recent neutron scattering experiments of Boni et al. and also Bohn et al. Our calculated auto-correlation function shows a diffusive behaviour temporally. (author). 15 refs, 5 figs

  6. THz Electron Paramagnetic Resonance / THz Spectroscopy at BESSY II

    Karsten Holldack

    2016-02-01

    Full Text Available The THz beamline at BESSY II employs high power broadband femto- to picosecond long THz pulses for magneto-optical THz and FIR studies. A newly designed set-up exploits the unique properties of ultrashort THz pulses generated by laser-energy modulation of electron bunches in the storage ring or alternatively from compressed electron bunches. Experiments from 0.15 to 5 THz (~ 5 – 150 cm-1 may be conducted at a user station equipped with a fully evacuated high resolution FTIR spectrometer (0.0063 cm-1, lHe cooled bolometer detectors, a THz TDS set-up and different sample environments, including a superconducting high field magnet (+11 T - 11T with variable temperature insert (1.5 K – 300 K, a sample cryostat and a THz attenuated total reflection chamber.  Main applications are Frequency Domain Fourier transform THz-Electron Paramagnetic Resonance (FD-FT THz-EPR, THz-FTIR spectroscopy and optical pump - THz probe time domain spectroscopy (TDS, with sub-ps time resolution.

  7. Cation Binding to Xanthorhodopsin: Electron Paramagnetic Resonance and Magnetic Studies.

    Smolensky Koganov, Elena; Leitus, Gregory; Rozin, Rinat; Weiner, Lev; Friedman, Noga; Sheves, Mordechai

    2017-05-04

    Xanthorhodopsin (xR) is a member of the retinal protein family and acts as a proton pump in the cell membranes of the extremely halophilic eubacterium Salinibacter ruber. In addition to the retinal chromophore, xR contains a carotenoid, which acts as a light-harvesting antenna as it transfers 40% of the quanta it absorbs to the retinal. Our previous studies have shown that the CD and absorption spectra of xR are dramatically affected due to the protonation of two different residues. It is still unclear whether xR can bind cations. Electron paramagnetic resonance (EPR) spectroscopy used in the present study revealed that xR can bind divalent cations, such as Mn 2+ and Ca 2+ , to deionized xR (DI-xR). We also demonstrate that xR can bind 1 equiv of Mn 2+ to a high-affinity binding site followed by binding of ∼40 equiv in cooperative manner and ∼100 equiv of Mn 2+ that are weakly bound. SQUID magnetic studies suggest that the high cooperative binding of Mn 2+ cations to xR is due to the formation of Mn 2+ clusters. Our data demonstrate that Ca 2+ cations bind to DI-xR with a lower affinity than Mn 2+ , supporting the assumption that binding of Mn 2+ occurs through cluster formation, because Ca 2+ cations cannot form clusters in contrast to Mn 2+ .

  8. Biophysical dose measurement using electron paramagnetic resonance in rodent teeth

    Khan, R.F.H.; Rink, W.J.; Boreham, D.R.

    2003-01-01

    Electron paramagnetic resonance (EPR) dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. However, there are situations that do not involve a human victim (e.g. tests for suspected environmental overexposures, measurements of doses to experimental animals in radiation biology research, or chronology of archaeological deposits). For such cases we have developed an EPR dosimetry technique making use of enamel of teeth extracted from mice. Tooth enamel from both previously irradiated and unirradiated mice was extracted and cleaned by processing in supersaturated KOH aqueous solution. Teeth from mice with no previous irradiation history exhibited a linear EPR response to the dose in the range from 0.8 to 5.5 Gy. The EPR dose reconstruction for a preliminarily irradiated batch resulted in the radiation dose of (1.4±0.2) Gy, which was in a good agreement with the estimated exposure of the teeth. The sensitivity of the EPR response of mouse enamel to gamma radiation was found to be half of that of human tooth enamel. The dosimetric EPR signal of mouse enamel is stable up at least to 42 days after exposure to radiation. Dose reconstruction was only possible with the enamel extracted from molars and premolars and could not be performed with incisors. Electron micrographs showed structural variations in the incisor enamel, possibly explaining the large interfering signal in the non-molar teeth

  9. Natural Convective Heat Transfer from Narrow Plates

    Oosthuizen, Patrick H

    2013-01-01

    Natural Convective Heat Transfer from Narrow Plates deals with a heat transfer situation that is of significant practical importance but which is not adequately dealt with in any existing textbooks or in any widely available review papers. The aim of the book is to introduce the reader to recent studies of natural convection from narrow plates including the effects of plate edge conditions, plate inclination, thermal conditions at the plate surface and interaction of the flows over adjacent plates. Both numerical and experimental studies are discussed and correlation equations based on the results of these studies are reviewed.

  10. A naturally narrow positive-parity Θ+

    Carlson, Carl E.; Carone, Christopher D.; Kwee, Herry J.; Nazaryan, Vahagn

    2004-01-01

    We present a consistent color-flavor-spin-orbital wave function for a positive-parity Θ + that naturally explains the observed narrowness of the state. The wave function is totally symmetric in its flavor-spin part and totally antisymmetric in its color-orbital part. If flavor-spin interactions dominate, this wave function renders the positive-parity Θ + lighter than its negative-parity counterpart. We consider decays of the Θ + and compute the overlap of this state with the kinematically allowed final states. Our results are numerically small. We note that dynamical correlations between quarks are not necessary to obtain narrow pentaquark widths

  11. Narrow Escape of Interacting Diffusing Particles

    Agranov, Tal; Meerson, Baruch

    2018-03-01

    The narrow escape problem deals with the calculation of the mean escape time (MET) of a Brownian particle from a bounded domain through a small hole on the domain's boundary. Here we develop a formalism which allows us to evaluate the nonescape probability of a gas of diffusing particles that may interact with each other. In some cases the nonescape probability allows us to evaluate the MET of the first particle. The formalism is based on the fluctuating hydrodynamics and the recently developed macroscopic fluctuation theory. We also uncover an unexpected connection between the narrow escape of interacting particles and thermal runaway in chemical reactors.

  12. Electron paramagnetic resonance studies on conformation states and metal ion exchange properties of vanadium bromoperoxidase

    de Boer, E.; Boon, K.; Wever, R.

    1988-01-01

    An electron paramagnetic resonance (EPR) study was carried out to examine structural aspects of vanadium-containing bromoperoxidase from the brown seaweed Ascophyllum nodosum. At high pH, the reduced form of bromoperoxidase showed an apparently axially symmetric EPR signal with 16 hyperfine lines. When the pH was lowered, a new EPR spectrum was formed. When EPR spectra of the reduced enzyme were recorded in the pH range from 4.2 to 8.4, it appeared that these changes were linked to a functional group with an apparent pK/sub a/ of about 5.4. In D 2 O this value for the pK/sub a/ was 5.3. It is suggested that these effects arise from protonation of histidine or aspartate/glutamate residues near the metal ion. The values for the isotropic hyperfine coupling constant of the reduced enzyme at both high and low pH are also consistent with a ligand field containing nitrogen and/or oxygen donor atoms. When reduced bromoperoxidase was dissolved in D 2 O or H 2 17 O instead of H 2 16 O, vanadium (IV) hyperfine line widths were markedly affected, demonstrating that water is a ligand of the metal ion. Together with previous work these findings suggest that vanadium (IV) is not involved in catalytic turnover and confirm the model in which the vanadium (V) ion of the native enzyme only serves to bind both hydrogen peroxide and bromide. After excess vanadate was added to a homogeneous preparation of purified bromoperoxidase, the extent of vanadium bound to the protein increased from 0.5 to 1.1, with a concomitant enhancement of enzymic activity. Finally, it is demonstrated that both vanadate (VO 4 3- ) and molybdate (MoO 4 2- ) compete for the same site on apobromoperoxidase

  13. Investigation of lanthanide ions and other paramagnetic impurities in natural fluorite by electron paramagnetic resonance: examples of application to mining exploration and geochemistry

    Chatagnon, B.

    1981-01-01

    This research thesis reports the application to geology, and more particularly to geochemistry and mining exploration, of a physical method: the electron paramagnetic resonance (EPR). After a report of a bibliographical investigation on mineralogy and geochemistry of fluorite and lanthanides, as well as on paramagnetic centres observed by physicists in synthetic fluorite, the author reports an experimental work, and describes two examples of application of EPR: firstly, the exploration of radioactive ores, and secondly, with the joint use of neutron activation analysis, the characterization of the redox status of the hydrothermal solution which is at the origin of fluorinated mineralisation

  14. O2 atmospheric band measurements with WINDII: Performance of a narrow band filter/wide angle Michelson combination in space

    Ward, W.E.; Hersom, C.H.; Tai, C.C.; Gault, W.A.; Shepherd, G.G.; Solheim, B.H.

    1994-01-01

    Among the emissions viewed by the Wind Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite (UARS) are selected lines in the (0-0) transition of the O2 atmospheric band. These lines are viewed simultaneously using a narrow band filter/wide-angle Michelson interferometer combination. The narrow band filter is used to separate the lines on the CCD (spectral-spatial scanning) and the Michelson used to modulate the emissions so that winds and rotational temperatures may be measured from the Doppler shifts and relative intensities of the lines. In this report this technique will be outlined and the on-orbit behavior since launch summarized

  15. Antiferromagnetic–paramagnetic state transition of NiO synthesized by pulsed laser deposition

    Nkosi, SS

    2013-01-01

    Full Text Available respectively from Raman spectroscopy study. These particle sizes are known be affected by substrate temperature during the deposition. Electron spin resonance (ESR) results demonstrated a strange antiferromagnetic to paramagnetic transition at a room...

  16. Paramagnetic defects in KH{sub 2}PO{sub 4} crystals with high concentration of embedded TiO{sub 2} nanoparticles

    Grachev, Valentin G., E-mail: grachev@physics.montana.edu; Tse, Romand; Malovichko, Galina I. [Physics Department, Montana State University, Bozeman, Montana 59717 (United States); Pritula, Igor M.; Bezkrovnaya, Olga N.; Kosinova, Anna V. [Institute for Single Crystals, NAS of Ukraine, Kharkiv (Ukraine)

    2016-01-21

    Qualitative transformations of spectra of Electron Paramagnetic Resonance, EPR, were found in KH{sub 2}PO{sub 4} crystals grown from liquor with 10{sup −5}–10{sup −1 }wt. % of anatase TiO{sub 2} nanoparticles in comparison with nominally pure KH{sub 2}PO{sub 4}. The nanoparticles have larger segregation coefficient for prismatic parts of the crystals than for pyramidal ones. Significant decrease in resonance absorption, complete disappearance of EPR lines of Fe{sup 3+} and Cr{sup 3+} centers, and appearance of four weak lines of equal intensities together with broad asymmetric lines with g-factors about 2.07–2.5 was observed in pyramidal parts grown with concentration of TiO{sub 2} nanoparticles larger than the threshold value 10{sup −2 }wt. %. The four lines were attributed to non-controlled impurity As substituted for P. In the presence of TiO{sub 2} nanoparticles, non-paramagnetic AsO{sub 4}{sup 3−} clusters trap electrons becoming AsO{sub 4}{sup 4−}. Disappearance of Fe{sup 3+} and Cr{sup 3+} centers was explained by their recharge to “EPR-silent” states and/or pairing at the surface of TiO{sub 2} nanoparticles.

  17. Anomalous magnetism and electron paramagnetic resonance spectroscopy of the ZrNi1-xCrxSn solid solution

    Stadnyk, Y.V.; Skolozdra, R.V.; Gorelenko, Y.K.; Romaka, L.P.; Jankowska-Frydel, A.; Grinberg, M.

    2000-01-01

    The static magnetic properties and electron paramagnetic resonance (EPR) spectra of ZrNi 1-x Cr x Sn solid solution (0 pp =(120±5)G type and g=1.980±0.001, peak-to-peak width ΔH pp =(10±1)G, respectively. They have been attributed to Cr 3+ ions in Ni-sites of the lattice coupled by magnetic dipolar interaction (type I) and to exchange coupled Cr 3+ pairs or clusters of more than two Cr 3+ ions (type II). The third line detected in the samples with x=0.3,0.4 characterised by g eff =2.0003±0.0001 and ΔH pp =(3.0±0.5)G has been interpreted as conduction electron spin resonance (CESR). (orig.)

  18. Narrow linewidth pulsed optical parametric oscillator

    Tunable narrow linewidth radiation by optical parametric oscillation has many applications, particularly in spectroscopic investigation. In this paper, different techniques such as injection seeding, use of spectral selecting element like grating, grating and etalon in combination, grazing angle of incidence, entangled cavity ...

  19. Electron paramagnetic resonance study on the ionizing radiation induced defects of the tooth enamel hydroxyapatite

    Oliveira, Liana Macedo de

    1995-01-01

    Hydroxyapatite is the main constituent of calcified tissues. Defects induced by ionizing radiations in this biomineral can present high stability and then, these are used as biological markers in radiological accidents, irradiated food identifying and geological and archaeological dating. In this work, paramagnetic centers induced on the enamel of the teeth by environmental ionizing radiation, are investigated by electron paramagnetic resonance (EPR). Decay thermal kinetic presents high complexity and shows the formation of different electron ligation energy centers and structures

  20. Dosimetry of ionizing radiations by Electron paramagnetic resonance; Dosimetria de radiaciones ionizantes por resonancia paramagnetica electronica

    Azorin N, J [UAM-I, Av. San Rafael Atlixco 186, 09340 Mexico D.F. (Mexico)

    2005-07-01

    In this work, some historical and theoretical aspects about the Electron Paramagnetic Resonance (EPR), its characteristics, the resonance detection, the paramagnetic species, the radiation effects on inorganic and organic materials, the diagrams of the instrumentation for the EPR detection, the performance of an EPR spectrometer, the coherence among EPR and dosimetry and, practical applications as well as in the food science there are presented. (Author)

  1. Two-frequency radiospectrometer for studying paramagnetics under a strong magnetic field

    Vertii, A.A.; Gudym, I.Y.; Ivanchenko, I.V.

    1994-01-01

    A two-frequency radiospectrometer for studying electron paramagnetic resonance in the 120-150-GHz band and nuclear magnetic resonance in the 180-200-MHz band is described. The spectrometer is used to measure the properties of paramagnetics by a double-resonance technique in a magnetic field of up to 5 T at a temperature ranging from 1.7 to 20 degrees K

  2. Electrically-detected electron paramagnetic resonance of point centers in 6H-SiC nanostructures

    Bagraev, N.T.; Gets, D.S.; Kalabukhova, E.N.; Klyachkin, L.E.; Malyarenko, A.M.; Mashkov, V.A.; Savchenko, Dariia; Shanina, B.D.

    2014-01-01

    Roč. 48, č. 11 (2014), s. 1467-1480 ISSN 1063-7826 R&D Projects: GA MŠk(CZ) LM2011029 Grant - others:SAFMAT(XE) CZ.2.16/3.1.00/22132 Institutional support: RVO:68378271 Keywords : electron paramagnetic resonance * electrically- detected electron paramagnetic resonance * 6H -SiC nanostructures * nitrogen-vacancy defect * point defect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.739, year: 2014

  3. An NMR strategy for fragment-based ligand screening utilizing a paramagnetic lanthanide probe

    Saio, Tomohide; Ogura, Kenji; Shimizu, Kazumi; Yokochi, Masashi; Burke, Terrence R.; Inagaki, Fuyuhiko

    2011-01-01

    A nuclear magnetic resonance-based ligand screening strategy utilizing a paramagnetic lanthanide probe is presented. By fixing a paramagnetic lanthanide ion to a target protein, a pseudo-contact shift (PCS) and a paramagnetic relaxation enhancement (PRE) can be observed for both the target protein and its bound ligand. Based on PRE and PCS information, the bound ligand is then screened from the compound library and the structure of the ligand–protein complex is determined. PRE is an isotropic paramagnetic effect observed within 30 Å from the lanthanide ion, and is utilized for the ligand screening in the present study. PCS is an anisotropic paramagnetic effect providing long-range (∼40 Å) distance and angular information on the observed nuclei relative to the paramagnetic lanthanide ion, and utilized for the structure determination of the ligand–protein complex. Since a two-point anchored lanthanide-binding peptide tag is utilized for fixing the lanthanide ion to the target protein, this screening method can be generally applied to non-metal-binding proteins. The usefulness of this strategy was demonstrated in the case of the growth factor receptor-bound protein 2 (Grb2) Src homology 2 (SH2) domain and its low- and high-affinity ligands.

  4. Paramagnetic moments in YBa2Cu3O7−δ nanocomposite films

    Dias, F.T.; Vieira, V.N.; Silva, D.L.; Albino Aguiar, J.; Valadão, D.R.B.; Obradors, X.; Puig, T.; Wolff-Fabris, F.; Kampert, E.

    2014-01-01

    Highlights: • The paramagnetic Meissner effect was observed in a nanocomposite YBaCuO thin film. • The paramagnetic moments in FC experiments were observed up to 10 T. • The paramagnetic Meissner effect increases when the magnetic field is increased. • Results may be explained based on the flux compression scenario and vortex pinning. • An apparent saturation tendency of the paramagnetic moments could be observed. - Abstract: We report on magnetization studies in YBa 2 Cu 3 O 7−δ thin films with dispersed Ba 2 YTaO 6 nanoparticles. The magnetization measurements were made using a superconducting quantum interference device (SQUID) and a vibrating sample magnetometer (VSM). Magnetic moments were measured as functions temperature using zero-field cooling (ZFC) and field-cooled (FC) prescriptions for magnetic fields up to 10 T applied parallel and perpendicular to the ab planes. A paramagnetic response related to the superconducting state was observed during the FC experiments. This effect, known as paramagnetic Meissner effect (PME), apparently increases when the magnetic field is increased. We discuss our PME results in terms of the strong pinning scenario modulated by Ba 2 YTaO 6 nanoparticles dispersed into the superconducting matrix

  5. Narrow and broad solitons in the antiferromagnetic chains of CsCoCl3 and TMMC

    Boucher, J.P.; Regnault, L.P.; Pires, A.; Rossat-Mignod, J.; Henry, Y.; Bouillot, J.; Stirling, W.G.; Renard, J.P.

    1984-06-01

    The two quasi one-dimensional (1D) compounds CsCoCl 3 and (CH 3 ) 4 NMnCl 3 (TMMC) are almost ideal systems in which to study soliton excitations. Both they have antiferromagnetic (AF) couplings in the chains and at low temperature they exhibit an Ising symmetry favourable for the occurence of solitons. This symmetry is an intrinsic property of CsCoCl 3 while in TMMC it is only achieved by the application of an external magnetic field H perpendicular to the chains. In the lD short range order regime two energetically equivalent configurations are expected for the spins. Solitons can be seen as Bloch walls separating ordered domains and allowing the spins to pass from one configuration to the other. In the case of a ''strong'' Ising symmetry (CsCoCl 3 ) the walls are reduced to one lattice unit (''narrow'' solitons) while in the case of a ''weak'' Ising symmetry (TMMC) the walls extend over several lattice units (10 to 30) (''broad'' solitons). To maintain a paramagnetic state, these walls move rapidly along the chains inducing characteristic fluctuations. The investigation of these two compounds, CsCoCl 3 and TMMC illustrates the advantage of antiferromagnets as the AF mode yields an accurate determination of the soliton regime. Narrow and broad solitons are observed to behave very similarly

  6. Radiation-induced paramagnetic species in natural calcite speleothems

    Rossi, A.M.; Poupeau, G.

    1989-01-01

    The ESR natural spectrum of humic-free speleothem calcite single crytals in the region of g = 2.0000 is a composite of lines from 4 radiogenic species, in addition to Mn ++ lines. Laboratory irradiation causes appearrance of three more species. Use of isotropic F species (g = 2.0003) for dating is possible if specific cautions are followed. (author) [pt

  7. Radiation dosimetry in human bone using electron paramagnetic resonance

    Breen, S.L.

    1995-01-01

    Accurate measurements of dose in bone are required in order to improve the dosimetry of systemic radiotherapy for osseous metastases. Bone is an integrating dosimeter which records the radiation history of the skeleton. During irradiation, electrons become trapped in the crystalline component of bone mineral (hydroxyapatite). The traps are very stable; at room temperature, emptying of the traps occurs with a half-life of many years. The population of trapped unpaired electrons is proportional to the radiation dose administered to the bone and can be measured in excised bone samples using electron paramagnetic resonance (EPR). EPR spectra of synthetic hydroxyapatite, irradiated with Co-60, were obtained at room temperature and at 77 K. At room temperature, the radiation-induced signal, with a g-value of 2.001 ± 0.001 increased linearly with absorbed dose above a lower threshold of 3 Gy, up to doses of 200 Gy. In contrast with pure hydroxyapatite, EPR spectra of excised human bone showed a broad 'native' signal, due to the organic component of bone, which masks the dosimetrically important signal. This native signal is highly variable from sample to sample and precludes the use of EPR as an absolute dosimetry technique. However, after subtraction of the background signal, irradiated human bone showed a linear response with a lower limit of measurement similar to that of synthetic hydroxyapatite. Bone is an in vivo linear dosimeter which can be exploited to develop accurate estimates of the radiation dose delivered during systemic radiotherapy and teletherapy. However, improved sensitivity of the EPR dosimetry technique is necessary before it can be applied reliably in clinical situations. (author)

  8. Paramagnetic relaxation enhancements in NMR peptide-membrane interaction studies

    Kosol, S.

    2011-01-01

    Small membrane-bound proteins or peptides are involved in numerous essential biological processes, like cellular recognition, signaling, channel formation, and cytolysis. The secondary structure, orientation, mode of interaction and dynamics of these peptides can be as varied as their functions. Their localization in the membrane, the immersion depth, and their binding mode are factors critical to the function of these peptides. The atomic 3D solution structure of peptides bound to micelles can be determined by NMR spectroscopy. However, by employing paramagnetic relaxation enhancements (PREs) information on the complete topology of peptide bound to a micelle can be obtained. The antimicrobial peptide maximin H6, fst, a bacterial toxin, and the human peptide hormone ghrelin served as membrane-bound model peptides of similar sizes but strongly differing amino acid sequences. Their structures and binding behavior were determined and compared.The measured PREs provided suitable data for determining and distinguishing the different topologies of the investigated peptides bound to micelles. Maximin H6 and fst fold into α-helices upon insertion into a membrane, whereas the unstructured ghrelin is freely mobile in solution and interacts only via a covalently bound octanoyl group with the lipids. Maximin H6 is oriented parallel to the membrane surface, enabling the peptide to aggregate at the membrane water interface. Fst binds in transmembrane orientation with a protruding intrinsically disordered region near the C-terminus. Aside from determining the orientation of the bound peptides from the PREs, the moieties critical for membrane binding could be mapped in ghrelin. If suitable relaxation-edited spectra are acquired, the complete orientation and immersion depth of a peptide bound to a micelle can readily be obtained. (author) [de

  9. Electron paramagnetic resonance biophysical radiation dosimetry with tooth enamel

    Khan, Rao F.H.

    2003-01-01

    This thesis deals with the advancements made in the field of Electron Paramagnetic Resonance (EPR) for biophysical dosimetry with tooth enamel for accident, emergency, and retrospective radiation dose reconstruction. A methodology has been developed to measure retrospective radiation exposures in human tooth enamel. This entails novel sample preparation procedures with minimum mechanical treatment to reduce the preparation induced uncertainties, establish optimum measurement conditions inside the EPR cavity, post-process the measured spectrum with functional simulation of dosimetric and other interfering signals, and reconstruct dose. By using this technique, retrospective gamma exposures as low as 80±30 mGy have been successfully deciphered. The notion of dose modifier was introduced in EPR biodosimetry for low dose measurements. It has been demonstrated that by using the modified zero added dose (MZAD) technique for low radiation exposures, doses in 100 mGy ranges can be easily reconstructed in teeth that were previously thought useless for EPR dosimetry. Also, the use of a dose modifier makes robust dose reconstruction possible for higher radiation exposures. The EPR dosimetry technique was also developed for tooth samples extracted from rodents, which represent small tooth sizing. EPR doses in the molars, extracted from the mice irradiated with whole body exposures, were reassessed and shown to be correct within the experimental uncertainty. The sensitivity of human tooth enamel for neutron irradiation, obtained from the 3 MV McMaster K.N. Van de Graaff accelerator, was also studied. For the first time this work has shown that the neutron sensitivity of the tooth enamel is approximately 1/10th of the equivalent gamma sensitivity. Parametric studies for neutron dose rate and neutron energy within the available range of the accelerator, showed no impact on the sensitivity of the tooth enamel. Therefore, tooth enamel can be used as a dosimeter for both neutrons

  10. Electron paramagnetic resonance detection of carotenoid triplet states

    Frank, H.A.; Bolt, J.D.; deCosta, S.M.; Sauer, K.

    1980-01-01

    Triplet states of carotenoids have been detected by X-band electron paramagnetic resonance (EPR) and are reported here for the first time. The systems in which carotenoid triplets are observed include cells of photosynthetic bacteria, isolated bacteriochlorophyll-protein complexes, and detergent micelles which contain β-carotene. It is well known that if electron transfer is blocked following the initial acceptor in the bacterial photochemical reaction center, back reaction of the primary radical pair produces a bacteriochlorophyll dimer triplet. Previous optical studies have shown that in reaction centers containing carotenoids the bacteriochlorophyll dimer triplet sensitizes the carotenoid triplet. We have observed this carotenoid triplet state by EPR in reaction centers of Rhodopseudomonas sphaeroides, strain 2.4.1 (wild type), which contain the carotenoid spheroidene. The zero-field splitting parameters of the triplet spectrum are /D/ = 0.0290 +- 0.0005 cm -1 and /E/ = 0.0044 +-0.0006 cm -1 , in contrast with the parameters of the bacteriochlorophyll dimer triplet, which are /D/ = 0.0189 +- 0.0004 cm -1 and /E/ = 0.0032 +- 0.004 cm -1 . Bacteriochlorophyll in a light harvesting protein complex from Rps. sphaeroides, wild type, also sensitizes carotenoid triplet formation. In whole cells the EPR spectra vary with temperature between 100 and 10 K. Carotenoid triplets also have been observed by EPR in whole cells of Rps. sphaeroides and cells of Rhodospirillum rubrum which contain the carotenoid spirilloxanthin. Attempts to observe the triplet state EPR spectrum of β-carotene in numerous organic solvents failed. However, in nonionic detergent micelles and in phospholipid bilayer vesicles β-carotene gives a triplet state spectrum with /D/ = 0.0333 +- 0.0010 cm -1 and /E/ = 0.0037 +- 0.0010 cm -1 . 6 figures, 1 table

  11. A Novel Paramagnetic Substrate for Detecting Myeloperoxidase Activity in Vivo

    Mohammed S. Shazeeb

    2012-09-01

    Full Text Available Bis-phenylamides and bis-hydroxyindolamides of diethylenetriaminepentaacetic acid-gadolinium (DTPA(Gd are paramagnetic reducing substrates of peroxidases that enable molecular imaging of peroxidase activity in vivo. Specifically, gadolinium chelates of bis-5-hydroxytryptamide-DTPA (bis-5HT-DTPA(Gd have been used to image localized inflammation in animal models by detecting neutrophil-derived myeloperoxidase (MPO activity at the inflammation site. However, in other preclinical disease models, bis-5HT-DTPA(Gd presents technical challenges due to its limited solubility in vivo. Here we report a novel MPO-sensing probe obtained by replacing the reducing substrate serotonin (5-HT with 5-hydroxytryptophan (HTrp. Characterization of the resulting probe (bis-HTrp-DTPA(Gd in vitro using nuclear magnetic resonance spectroscopy and enzyme kinetic analysis showed that bis-HTrp-DTPA(Gd (1 improves solubility in water; (2 acts as a substrate for both horseradish peroxidase and MPO enzymes; (3 induces cross-linking of proteins in the presence of MPO; (4 produces oxidation products, which bind to plasma proteins; and (5 unlike bis-5HT-DTPA(Gd, does not follow first-order reaction kinetics. In vivo magnetic resonance imaging (MR! in mice demonstrated that bis-HTrp-DTPA(Gd was retained for up to 5 days in MPO-containing sites and cleared faster than bis-5HT-DTPA(Gd from MPO-negative sites. Bis-HTrp-DTPA(Gd should offer improvements for MR! of MPO-mediated inflammation in vivo, especially in high-field MR!, which requires a higher dose of contrast agent.

  12. A novel paramagnetic substrate for detecting myeloperoxidase activity in vivo.

    Shazeeb, Mohammed S; Xie, Yang; Gupta, Suresh; Bogdanov, Alexei A

    2012-01-01

    Bis-phenylamides and bis-hydroxyindolamides of diethylenetriaminepentaacetic acid-gadolinium (DTPA(Gd)) are paramagnetic reducing substrates of peroxidases that enable molecular imaging of peroxidase activity in vivo. Specifically, gadolinium chelates of bis-5-hydroxytryptamide-DTPA (bis-5HT-DTPA(Gd)) have been used to image localized inflammation in animal models by detecting neutrophil-derived myeloperoxidase (MPO) activity at the inflammation site. However, in other preclinical disease models, bis-5HT-DTPA(Gd) presents technical challenges due to its limited solubility in vivo. Here we report a novel MPO-sensing probe obtained by replacing the reducing substrate serotonin (5-HT) with 5-hydroxytryptophan (HTrp). Characterization of the resulting probe (bis-HTrp-DTPA(Gd)) in vitro using nuclear magnetic resonance spectroscopy and enzyme kinetic analysis showed that bis-HTrp-DTPA(Gd) (1) improves solubility in water; (2) acts as a substrate for both horseradish peroxidase and MPO enzymes; (3) induces cross-linking of proteins in the presence of MPO; (4) produces oxidation products, which bind to plasma proteins; and (5) unlike bis-5HT-DTPA(Gd), does not follow first-order reaction kinetics. In vivo magnetic resonance imaging (MRI) in mice demonstrated that bis-HTrp-DTPA(Gd) was retained for up to 5 days in MPO-containing sites and cleared faster than bis-5HT-DTPA(Gd) from MPO-negative sites. Bis-HTrp-DTPA(Gd) should offer improvements for MRI of MPO-mediated inflammation in vivo, especially in high-field MRI, which requires a higher dose of contrast agent.

  13. Evolution of deformation velocity in narrowing for Zircaloy 2

    Cetlin, P R [Minas Gerais Univ., Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica; Okuda, M Y [Goias Univ., Goiania (Brazil). Inst. de Matematica e Fisica

    1980-09-01

    Some studies on the deformation instability in strain shows that the differences in this instability may lead to localized narrowing or elongated narrowing, for Zircaloy-2. The variation of velocity deformation with the narrowing evolution is expected to be different for these two cases. The mentioned variation is discussed, a great difference in behavior having been observed for the case of localized narrowing.

  14. Evaluation of paramagnetic species in coals with iodine doping technique; Yoso tenkaho wo mochiita sekitanchu no jojiseishu no hyoka

    Aizawa, S.; Kumagai, H.; Chiba, T. [Hokkaido University, Sapporo (Japan). Center for Advanced Research of Energy Technology

    1996-10-28

    Electron paramagnetic resonance (EPR) of coals was considered by using iodine doping technique. Sub-bituminous coal (WA) and bituminous coal (UF) were used to observe EPR spectra using microwaves. With the UF coal, strength of the narrow component of the spectra was found constant regardless of amount of the doped iodine, wherein radicals without interaction with iodine were detected. Strength of the broad component increased with the iodine doping amount, where in deviation of {pi} electrons was detected, which have been generated as a result of interaction between aromatic rings and iodine in the coals. Spin concentration of the WA coal with low coalification degree is constant regardless of the iodine doping amount, and the interaction of the iodine with the aromatic rings was found small. The higher the coalification degree, the more the aromatic ring structure grows, and electron donor capability for the iodine increases. In a system with the entire spin being uniform, the spectrum height shows a saturation phenomenon against increase in microwave output. A non-uniform system, in which the oriented spin forms small groups and is in local thermal equilibrium, does not show saturation, but increases monotonously. 2 refs., 5 figs.

  15. Spectral design of temperature-invariant narrow bandpass filters for the mid-infrared

    Stolberg-Rohr, Thomine Kirstine; Hawkins, Gary J.

    2015-01-01

    The ability of narrow bandpass filters to discriminatewavelengths between closely-separated gas absorption lines is crucial inmany areas of infrared spectroscopy. As improvements to the sensitivity ofinfrared detectors enables operation in uncontrolled high-temperature environments, this imposes ...... presents the results of an investigation into the interdependence between multilayer bandpass designand optical materials together with a review on invariance at elevated temperatures....

  16. Analytical approximations for wide and narrow resonances

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da

    2005-01-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U 238 were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  17. Analytical approximations for wide and narrow resonances

    Suster, Luis Carlos; Martinez, Aquilino Senra; Silva, Fernando Carvalho da [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia. Programa de Engenharia Nuclear]. E-mail: aquilino@lmp.ufrj.br

    2005-07-01

    This paper aims at developing analytical expressions for the adjoint neutron spectrum in the resonance energy region, taking into account both narrow and wide resonance approximations, in order to reduce the numerical computations involved. These analytical expressions, besides reducing computing time, are very simple from a mathematical point of view. The results obtained with this analytical formulation were compared to a reference solution obtained with a numerical method previously developed to solve the neutron balance adjoint equations. Narrow and wide resonances of U{sup 238} were treated and the analytical procedure gave satisfactory results as compared with the reference solution, for the resonance energy range. The adjoint neutron spectrum is useful to determine the neutron resonance absorption, so that multigroup adjoint cross sections used by the adjoint diffusion equation can be obtained. (author)

  18. Dose evaluation of narrow-beam

    Goto, Shinichi

    1999-01-01

    Reliability of the dose from the narrow photon beam becomes more important since the single high-dose rate radiosurgery becoming popular. The dose evaluation for the optimal dose is difficult due to absence of lateral electronic equilibrium. Data necessary for treatment regimen are TMR (tissue maximum ratio), OCR (off center ratio) and S c,p (total scatter factor). The narrow-beam was 10 MV X-ray from Varian Clinac 2100C equipped with cylindrical Fischer collimator CBI system. Detection was performed by Kodak XV-2 film, a PTW natural diamond detector M60003, Scanditronics silicon detector EDD-5 or Fujitec micro-chamber FDC-9.4C. Phantoms were the water equivalent one (PTW, RW3), water one (PTW, MP3 system) and Wellhofer WP600 system. Factors above were actually measured to reveal that in the dose evaluation of narrow photon beam, TMR should be measured by micro-chamber, OCR, by film, and S c,p , by the two. The use of diamond detector was recommended for more precise measurement and evaluation of the dose. The importance of water phantom in the radiosurgery system was also shown. (K.H.)

  19. Electron correlations in narrow band systems

    Kishore, R.

    1983-01-01

    The effect of the electron correlations in narrow bands, such as d(f) bands in the transition (rare earth) metals and their compounds and the impurity bands in doped semiconductors is studied. The narrow band systems is described, by the Hubbard Hamiltonian. By proposing a local self-energy for the interacting electron, it is found that the results are exact in both atomic and band limits and reduce to the Hartree Fock results for U/Δ → 0, where U is the intra-atomic Coulomb interaction and Δ is the bandwidth of the noninteracting electrons. For the Lorentzian form of the density of states of the noninteracting electrons, this approximation turns out to be equivalent to the third Hubbard approximation. A simple argument, based on the mean free path obtained from the imaginary part of the self energy, shows how the electron correlations can give rise to a discontinous metal-nonmetal transition as proposed by Mott. The band narrowing and the existence of the satellite below the Fermi energy in Ni, found in photoemission experiments, can also be understood. (Author) [pt

  20. Pool Boiling CHF in Inclined Narrow Annuli

    Kang, Myeong Gie

    2010-01-01

    Pool boiling heat transfer has been studied extensively since it is frequently encountered in various heat transfer equipment. Recently, it has been widely investigated in nuclear power plants for application to the advanced light water reactors designs. Through the review on the published results it can be concluded that knowledge on the combined effects of the surface orientation and a confined space on pool boiling heat transfer is of great practical importance and also of great academic interest. Fujita et al. investigated pool boiling heat transfer, from boiling inception to the critical heat flux (CHF, q' CHF ), in a confined narrow space between heated and unheated parallel rectangular plates. They identified that both the confined space and the surface orientation changed heat transfer much. Kim and Suh changed the surface orientation angles of a downward heating rectangular channel having a narrow gap from the downward-facing position (180 .deg.) to the vertical position (90 .deg.). They observed that the CHF generally decreased as the inclination angle (θ ) increased. Yao and Chang studied pool boiling heat transfer in a confined heat transfer for vertical narrow annuli with closed bottoms. They observed that when the gap size ( s ) of the annulus was decreased the effect of space confinement to boiling heat transfer increased. The CHF was occurred at much lower value for the confined space comparing to the unconfined pool boiling. Pool boiling heat transfer in narrow horizontal annular crevices was studied by Hung and Yao. They concluded that the CHF decreased with decreasing gap size of the annuli and described the importance of the thin film evaporation to explain the lower CHF of narrow crevices. The effect of the inclination angle on the CHF on countercurrent boiling in an inclined uniformly heated tube with closed bottoms was also studied by Liu et al. They concluded that the CHF reduced with the inclination angle decrease. A study was carried out

  1. Determination of g-tensors of low-symmetry Nd{sup 3+} centers in LiNbO{sub 3} by rectification of angular dependence of electron paramagnetic resonance spectra

    Grachev, V., E-mail: grachev@physics.montana.edu; Malovichko, G. [Physics Department, Montana State University, Bozeman, Montana 59717 (United States); Munro, M. [Quantel Laser, Bozeman, Montana 59715 (United States); Kokanyan, E. [Institute of Physical Researches, Ashtarak (Armenia)

    2015-07-28

    Two procedures for facilitation of line tracing and deciphering of complicated spectra of electron paramagnetic resonance (EPR) were developed: a correction of microwave frequencies for every orientation of external magnetic field on the base of known values of g-tensor components for a reference paramagnetic center and followed rectification of measured angular dependences using plots of effective deviation of g{sup 2}-factors of observed lines from effective g{sup 2}-factors of the reference center versus angles or squared cosines of angles describing magnetic field orientations. Their application to EPR spectra of nearly stoichiometric lithium niobate crystals doped with neodymium allowed identifying two axial and six different low-symmetry Nd{sup 3+} centers, to determine all components of their g-tensors, and to propose common divacancy models for a whole family of Nd{sup 3+} centers.

  2. The influence of microscopic disorder on electron paramagnetic resonance spectra of Eu2+ ions in Pb1-xGexTe

    Radzynski, T; Lusakowski, A; Swiatek, K; Story, T

    2009-01-01

    In mixed crystals, because of the different ionic radii of cations or anions and the randomness in the placement of ions of different kinds, the crystal lattice is locally deformed. Such local deformations have significant influence on the ground state splitting of magnetic ions. Because this ground state splitting is responsible for the position of the electron paramagnetic resonance (EPR) lines, microscopic disorder is one of the factors which lead to the broadening of the lines, and eventually to their disappearance. This paper is devoted to semi-quantitative analysis of the influence of microscopic disorder on EPR spectra. The theory is compared against measurements performed on mono-crystalline Pb 1-x Ge x Te epitaxial layers containing Eu 2+ ions for different germanium and europium contents. With increasing germanium content we observe gradual disappearance of the EPR lines, although macroscopically, on the basis of x-ray diffraction analysis, each layer might have been considered as a perfect crystal.

  3. PARAssign-paramagnetic NMR assignments of protein nuclei on the basis of pseudocontact shifts

    Skinner, Simon P., E-mail: skinnersp@chem.leidenuniv.nl [Leiden University, Gorlaeus Laboratories, Leiden Institute of Chemistry (Netherlands); Moshev, Mois, E-mail: mois@monomon.me [Leiden University, Leiden Institute of Advanced Computer Science (Netherlands); Hass, Mathias A. S., E-mail: hassmas@chem.leidenuniv.nl; Ubbink, Marcellus, E-mail: m.ubbink@chem.leidenuniv.nl [Leiden University, Gorlaeus Laboratories, Leiden Institute of Chemistry (Netherlands)

    2013-04-15

    The use of paramagnetic NMR data for the refinement of structures of proteins and protein complexes is widespread. However, the power of paramagnetism for protein assignment has not yet been fully exploited. PARAssign is software that uses pseudocontact shift data derived from several paramagnetic centers attached to the protein to obtain amide and methyl assignments. The ability of PARAssign to perform assignment when the positions of the paramagnetic centers are known and unknown is demonstrated. PARAssign has been tested using synthetic data for methyl assignment of a 47 kDa protein, and using both synthetic and experimental data for amide assignment of a 14 kDa protein. The complex fitting space involved in such an assignment procedure necessitates that good starting conditions are found, both regarding placement and strength of paramagnetic centers. These starting conditions are obtained through automated tensor placement and user-defined tensor parameters. The results presented herein demonstrate that PARAssign is able to successfully perform resonance assignment in large systems with a high degree of reliability. This software provides a method for obtaining the assignments of large systems, which may previously have been unassignable, by using 2D NMR spectral data and a known protein structure.

  4. High field electron paramagnetic resonance spectroscopy under ultrahigh vacuum conditions—A multipurpose machine to study paramagnetic species on well defined single crystal surfaces

    Rocker, J.; Cornu, D.; Kieseritzky, E.; Hänsel-Ziegler, W.; Freund, H.-J. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Seiler, A. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Laboratorium für Applikationen der Synchrotronstrahlung, KIT Campus Süd, Kaiserstr. 12, 76131 Karlsruhe (Germany); Bondarchuk, O. [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); CIC energiGUNE, Parque Tecnologico, C/Albert Einstein 48, CP 01510 Minano (Alava) (Spain); Risse, T., E-mail: risse@chemie.fu-berlin.de [Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin (Germany); Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195 Berlin (Germany)

    2014-08-01

    A new ultrahigh vacuum (UHV) electron paramagnetic resonance (EPR) spectrometer operating at 94 GHz to investigate paramagnetic centers on single crystal surfaces is described. It is particularly designed to study paramagnetic centers on well-defined model catalysts using epitaxial thin oxide films grown on metal single crystals. The EPR setup is based on a commercial Bruker E600 spectrometer, which is adapted to ultrahigh vacuum conditions using a home made Fabry Perot resonator. The key idea of the resonator is to use the planar metal single crystal required to grow the single crystalline oxide films as one of the mirrors of the resonator. EPR spectroscopy is solely sensitive to paramagnetic species, which are typically minority species in such a system. Hence, additional experimental characterization tools are required to allow for a comprehensive investigation of the surface. The apparatus includes a preparation chamber hosting equipment, which is required to prepare supported model catalysts. In addition, surface characterization tools such as low energy electron diffraction (LEED)/Auger spectroscopy, temperature programmed desorption (TPD), and infrared reflection absorption spectroscopy (IRAS) are available to characterize the surfaces. A second chamber used to perform EPR spectroscopy at 94 GHz has a room temperature scanning tunneling microscope attached to it, which allows for real space structural characterization. The heart of the UHV adaptation of the EPR experiment is the sealing of the Fabry-Perot resonator against atmosphere. To this end it is possible to use a thin sapphire window glued to the backside of the coupling orifice of the Fabry Perot resonator. With the help of a variety of stabilization measures reducing vibrations as well as thermal drift it is possible to accumulate data for a time span, which is for low temperature measurements only limited by the amount of liquid helium. Test measurements show that the system can detect paramagnetic

  5. About kinetics of paramagnetic radiation malformations in beryllium ceramics; O kinetike nakopleniya paramagnitnykh radiatsionnykh defectov v berillievykh keramikakh

    Polyakov, A I; Ryabinkin, Yu A; Zashkvara, O V; Bitenbaev, M I [Fiziko-tekhniucheskij Inst. Ministerstva Nauki i Vysshego Obrazovaniya Respubliki Kazakhstan, Almaty (Kazakhstan); Petukhov, Yu V [Inst. Atomnoj Ehnergii Natsional' nogo Yadernogo Tsentra Respubliki Kazakhstan, Almaty (Kazakhstan)

    1999-07-01

    This paper [1] specifies that {gamma}-radiation of the beryllium-oxide-based ceramics results in development of paramagnetic radiation malformations emerging the ESR spectrum in form of doublet with the splitting rate of oestrasid {delta}{approx}1.6 and g-factor of 2.008. This report presents evaluation outcomes of dependence of paramagnetic radiation malformations concentration in beryllium ceramics on gamma-radiation dose ({sup 60}Co) within the range of 0-100 Mrad. Total paramagnetic parameters of beryllium ceramics in the range 0-100 Mrad of gamma-radiation dose varied slightly, and were specified by the first type of paramagnetic radiation malformations.

  6. Faraday effect in γ-Dy2S3 and c-Dy2O3 paramagnetic crystals

    Shelykh, A.I.

    1987-01-01

    Studies of spectral and temperature dependences of Faraday effect in γ-Dy 2 S 3 and C-Dy 2 O 3 paramagnetic crystals are conducted. Paramagnetism of these crystals is brought about by Dy 3+ ions. Estimation of the effect of such factors as the value of paramagnetic ion concentration, width of the forbidden band, crystallochemical composition on magnetooptical effect in the considered compounds of dysprosium is carried out on the basis of the obtained experimental data and theoretical analysis. It is shown, that the Faraday effect in the considered compounds of dysprosium as well as the value of paramagnetic moment may be regarded rather accurately in free ion approximation

  7. Theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency

    Liu, Yang; Li, Shu-qing; Feng, Zhong-ying; Liu, Xiao-fei; Gao, Jin-yue

    2016-12-01

    To obtain the weak signal light detection from the high background noise, we present a theoretical study on the ultra-narrow bandwidth tunable atomic filter with electromagnetically induced transparency. In a three-level Λ -type atomic system in the rubidium D1 line, the bandwidth of the EIT atomic filter is narrowed to ~6.5 \\text{MHz} . And the single peak transmission of the filter can be up to 86% . Moreover, the transmission wavelength can be tuned by changing the coupling light frequency. This theoretical scheme can also be applied to other alkali atomic systems.

  8. Dicke coherent narrowing in two-photon and Raman spectroscopy of thin vapor cells

    Dutier, Gabriel; Todorov, Petko; Hamdi, Ismahene; Maurin, Isabelle; Saltiel, Solomon; Bloch, Daniel; Ducloy, Martial

    2005-01-01

    The principle of coherent Dicke narrowing in a thin vapor cell, in which sub-Doppler spectral line shapes are observed under a normal irradiation for a λ/2 thickness, is generalized to two-photon spectroscopy. Only the sum of the two wave vectors must be normal to the cell, making the two-photon scheme highly versatile. A comparison is provided between the Dicke narrowing with copropagating fields, and the residual Doppler broadening occurring with counterpropagating geometries. The experimental feasibility is discussed on the basis of a first observation of a two-photon resonance in a 300-nm-thick Cs cell. Extension to the Raman situation is finally considered

  9. Is light narrowing possible with dense-vapor paraffin coated cells for atomic magnetometers?

    Han, Runqi; Balabas, Mikhail; Hovde, Chris; Li, Wenhao; Roig, Hector Masia; Wang, Tao; Wickenbrock, Arne; Zhivun, Elena; You, Zheng; Budker, Dmitry

    2017-12-01

    We investigated the operation of an all-optical rubidium-87 atomic magnetometer with amplitude-modulated light. To study the suppression of spin-exchange relaxation, three schemes of pumping were implemented with room-temperature and heated paraffin coated vacuum cells. Efficient pumping and accumulation of atoms in the F=2 ground state were obtained. However, the sought-for narrowing of the resonance lines has not been achieved. A theoretical analysis of the polarization degree is presented to illustrate the absence of light narrowing due to radiation trapping at high temperature.

  10. Cervical spinal canal narrowing in idiopathic syringomyelia

    Struck, Aaron F.; Carr, Carrie M.; Shah, Vinil; Hesselink, John R.; Haughton, Victor M.

    2016-01-01

    The cervical spine in Chiari I patient with syringomyelia has significantly different anteroposterior diameters than it does in Chiari I patients without syringomyelia. We tested the hypothesis that patients with idiopathic syringomyelia (IS) also have abnormal cervical spinal canal diameters. The finding in both groups may relate to the pathogenesis of syringomyelia. Local institutional review boards approved this retrospective study. Patients with IS were compared to age-matched controls with normal sagittal spine MR. All subjects had T1-weighted spin-echo (500/20) and T2-weighted fast spin-echo (2000/90) sagittal cervical spine images at 1.5 T. Readers blinded to demographic data and study hypothesis measured anteroposterior diameters at each cervical level. The spinal canal diameters were compared with a Mann-Whitney U test. The overall difference was assessed with a Friedman test. Seventeen subjects were read by two reviewers to assess inter-rater reliability. Fifty IS patients with 50 age-matched controls were studied. IS subjects had one or more syrinxes varying from 1 to 19 spinal segments. Spinal canal diameters narrowed from C1 to C3 and then enlarged from C5 to C7 in both groups. Diameters from C2 to C4 were narrower in the IS group (p < 0.005) than in controls. The ratio of the C3 to the C7 diameters was also smaller (p = 0.004) in IS than controls. Collectively, the spinal canal diameters in the IS were significantly different from controls (Friedman test p < 0.0001). Patients with IS have abnormally narrow upper and mid cervical spinal canal diameters and greater positive tapering between C3 and C7. (orig.)

  11. Cervical spinal canal narrowing in idiopathic syringomyelia

    Struck, Aaron F. [Massachusetts General Hospital, Department of Neurology, Boston, MA (United States); Carr, Carrie M. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Shah, Vinil [University of California San Francisco, Department of Radiology, San Francisco, CA (United States); Hesselink, John R. [University of California San Diego, Department of Radiology, San Diego, CA (United States); Haughton, Victor M. [University of Wisconsin, Department of Radiology, Madison, WI (United States)

    2016-08-15

    The cervical spine in Chiari I patient with syringomyelia has significantly different anteroposterior diameters than it does in Chiari I patients without syringomyelia. We tested the hypothesis that patients with idiopathic syringomyelia (IS) also have abnormal cervical spinal canal diameters. The finding in both groups may relate to the pathogenesis of syringomyelia. Local institutional review boards approved this retrospective study. Patients with IS were compared to age-matched controls with normal sagittal spine MR. All subjects had T1-weighted spin-echo (500/20) and T2-weighted fast spin-echo (2000/90) sagittal cervical spine images at 1.5 T. Readers blinded to demographic data and study hypothesis measured anteroposterior diameters at each cervical level. The spinal canal diameters were compared with a Mann-Whitney U test. The overall difference was assessed with a Friedman test. Seventeen subjects were read by two reviewers to assess inter-rater reliability. Fifty IS patients with 50 age-matched controls were studied. IS subjects had one or more syrinxes varying from 1 to 19 spinal segments. Spinal canal diameters narrowed from C1 to C3 and then enlarged from C5 to C7 in both groups. Diameters from C2 to C4 were narrower in the IS group (p < 0.005) than in controls. The ratio of the C3 to the C7 diameters was also smaller (p = 0.004) in IS than controls. Collectively, the spinal canal diameters in the IS were significantly different from controls (Friedman test p < 0.0001). Patients with IS have abnormally narrow upper and mid cervical spinal canal diameters and greater positive tapering between C3 and C7. (orig.)

  12. Intensities, broadening and narrowing parameters in the ν3 band of methane

    Es-sebbar, Et-touhami

    2014-12-01

    The P-branch of methane\\'s ν3 band is probed to carry out an extensive study of the 2905-2908cm-1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening coefficients are determined for nine transitions at room temperature. Narrowing parameters due to the Dicke effect have also been investigated. A narrow emission line-width (~0.0001cm-1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4 spectroscopic parameters, Voigt and Galatry profiles were used to simulate the measured line shape of the individual transitions.

  13. Volume dips; spot price ranges narrow

    Anon.

    1994-01-01

    This article is the September 1994 uranium market summary. Volume in the spot concentrates market fell below 1 million lbs U3O8. In total, twelve deals took place compared to 28 deals in August. Of the twelve deals, three took place in the spot concentrates market, two took place in the medium and long-term market, three in the conversion market, and four in the enrichment market. Restricted prices weakened, but unrestricted prices firmed slightly. The enrichment price range narrowed a bit

  14. f-band narrowing in uranium intermetallics

    Dunlap, B.D.; Litterst, F.J.; Malik, S.K.; Kierstead, H.A.; Crabtree, G.W.; Kwok, W.; Lam, D.J.; Mitchell, A.W.

    1987-01-01

    Although the discovery of heavy fermion behavior in uranium compounds has attracted a great deal of attention, relatively little work has been done which is sufficiently systematic to allow an assessment of the relationship of such behavior to more common phenomena, such as mixed valence, narrow-band effects, etc. In this paper we report bulk property measurements for a number of alloys which form a part of such a systematic study. The approach has been to take relatively simple and well-understood materials and alter their behavior by alloying to produce heavy fermion or Kondo behavior in a controlled way

  15. Critical unpairing currents in narrow niobium films

    Gershenzon, M.E.; Gubankov, V.N.

    1979-01-01

    Investigated are the dependences of critical currents of narrow ( with the width of W=0.5-15 μm) superconducting niobium films on temperature and a magnetic field. The proposed method of film production with the width of the 1μm order and with small edge inhomogeneities ((<=500 A) permitted to realize the Ginsburg-Landau unpairing currents in the wide range of temperatures. The correct comparison with the theory showed that the unpairing currents are observed if W(< or approximately) 2delta, where delta is the effective depth of the penetration of the perpendicular magnetic field

  16. Narrow electron injector for ballistic electron spectroscopy

    Kast, M.; Pacher, C.; Strasser, G.; Gornik, E.

    2001-01-01

    A three-terminal hot electron transistor is used to measure the normal energy distribution of ballistic electrons generated by an electron injector utilizing an improved injector design. A triple barrier resonant tunneling diode with a rectangular transmission function acts as a narrow (1 meV) energy filter. An asymmetric energy distribution with its maximum on the high-energy side with a full width at half maximum of ΔE inj =10 meV is derived. [copyright] 2001 American Institute of Physics

  17. Narrow-Bicliques: Cryptanalysis of Full IDEA

    Khovratovich, D.; Leurent, G.; Rechberger, C.

    2012-01-01

    We apply and extend the recently introduced biclique framework to IDEA and for the first time describe an approach to noticeably speed-up key-recovery for the full 8.5 round IDEA.We also show that the biclique approach to block cipher cryptanalysis not only obtains results on more rounds, but also...... extended with ways to allow for a significantly reduced data complexity with everything else being equal. For this we use available degrees of freedom as known from hash cryptanalysis to narrow the relevant differential trails. Our cryptanalysis is of high computational complexity, and does not threaten...

  18. Radiation-induced electron paramagnetic resonance signal and soybean isoflavones content

    Oliveira, Marcos R.R. de; Mandarino, José M.G.; Mastro, Nelida L. del

    2012-01-01

    Electron Paramagnetic Resonance (EPR) is a well-known spectroscopic technique that detects paramagnetic centers and can detect free radicals with high sensitivity. In food, free radicals can be generated by several commonly used industrial processes, such as radiosterilization or heat treatment. EPR spectroscopy is used to detect radioinduced free radicals in food. In this work the relation between EPR signal induced by gamma irradiation treatment and soybean isoflavones content was investigated. Present results did not show correlation between total isoflavones content and the EPR signal. Nevertheless, some isoflavone contents had a negative correlation with the radiation-induced EPR signal. - Highlights: ► Electron Paramagnetic Resonance (EPR) detects free radicals. ► Ionizing radiation as free radicals inducer. ► Total soybean isoflvones do not correlate with radiation-induced EPR intensity but a soybean glucosyl glucoside isoflavone does.

  19. Refinement of the ferri and paramagnetic phases of magnetite measured by neutron multiple diffraction

    Mazzochi, V.L.; Parente, C.B.R.

    1989-10-01

    Structural parameters of the ferri and paramagnetic phases of magnetite have been refined from neutron multiple diffraction data. Experimental patterns were obtained by measuring the III primary reflection of a natural single crystal of this compound, at room temperature for the ferrimagnetic phase and 703 0 C for the paramagnetic phase. Theoretical multiple diffraction patterns for both phases have been calculated by the program MULTI which uses the iterative method. In this method intensities are caluclated as Taylor series expansions summed up to a order sufficient for a good approximation. A step by step process has been used in the refinements similarly to the parameter-shift method. Final values for the discrepancy factor found for the ferri and paramagnetic phases were R = 3.96% and R = 3.46%, respectively. (author) [pt

  20. Thermoluminescence, infrared reflectivity and electron paramagnetic resonance properties of hemimorphite

    Gallegos, E.A. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo, SP (Brazil); Cano, N.F. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo, SP (Brazil)], E-mail: nilocano@dfn.if.usp.br; Watanabe, S.; Chubaci, J.F.D. [Institute of Physics, University of Sao Paulo, Rua do Matao, Travessa R, 187, CEP 05508-900, Sao Paulo, SP (Brazil)

    2009-01-15

    Silicate mineral hemimorphite has been investigated concerning its TL, IR and EPR properties. A broad TL peak around 180 deg. C and a weaker and narrower peak around 360 deg. C were found in a sample annealed at 600 deg. C for 1 h and then irradiated. The deconvolution using the CGCD method revealed peaks around 132, 169, 222 and 367 deg. C. The reflectivity measurements showed several bands in the NIR region due to H{sub 2}O, OH and Al-OH complexes. No band was observed in the visible region. The thermal treatments were carried out from {approx}110 to 940 deg. C and dehydration was observed, first causing a diminishing optical absorption in general and the disappearance of water and hydroxyl absorption bands. The EPR spectrum of natural hemimorphite, presented Cu{sup 2+} signals at g = 2.4 and g = 2.1 plus E{sub 1}' signal superposed to Fe{sup 3+} signal around g = 2.0.

  1. Narrow field electromagnetic sensor system and method

    McEwan, T.E.

    1996-01-01

    A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments. 12 figs

  2. Dosimetry of narrow band UVB treatments

    Goode, D.H.; Mannering, D.M.

    1996-01-01

    Full text: For many years psoriasis has been treated with broad band UVB lamps. These lamps have a bell shaped spectrum which peaks at 305 nm and extends from 280 nm to 350 nm. However research with monochromatic UV radiation has shown that wavelengths between 300 nm and 320 nm are the most efficacious for clearing psoriasis while wavelengths below 305 nm are most effective for producing the undesirable side effect of erythema (sunburn). In response to these findings Philips developed a narrow band UVB tube in which a large fraction of the output was confined to a narrow peak (bandwidth 2.5 nm) situated at 311 nm. Christchurch Hospital replaced broad band UVB with narrow band treatments in August 1995 and as this required UV exposures to be substantially increased new protocols had to be developed. Three aspects needed to be addressed. These were translating the dose from broad band to narrow band for current patients, determining the initial dose for new patients and developing a formula for increasing subsequent exposures to both types of patient. To translate doses the spectral irradiance (μW/cm 2 /nm) that would fall on the patient was measured in both the old broad band and the new narrow band treatment units and from this UV doses were calculated. All doses were expressed in mJ/cm 2 of unweighted UV over the range 250 nm to 400 nm. The erythemal effectiveness of the two units were compared by using the CIE 1987 curve to express doses in terms of the equivalent exposure of monochromatic 297 nm radiation. It was found that an exposure of 3.96 mJ/cm 2 from the broad band FS40 tubes and 12.79 mJ/cm 2 from the narrow band TL/01 tubes were both equivalent to 1.00 mJ/cm 2 of monochromatic 297 nm radiation so when transferring patients all broad band doses needed to be increased by a factor of 3.2. Before transferring any patients this factor was confirmed by conducting two minimal erythema dose (MED) tests on a normal subject, one in each unit. For new patients a

  3. A methodology to enlarge narrow stability windows

    Araujo, Ewerton M.P.; Pastor, Jorge A.S.C.; Fontoura, Sergio A.B. [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil). Dept. de Engenharia Civil. Grupo de Tecnologia e Engenharia de Petroleo

    2004-07-01

    The stability window in a wellbore design is defined by the difference between fracture pressure and collapse pressure. Deep water environments typically present narrow stability windows, because rocks have low strength due to under-compaction process. Often also, horizontal wells are drilled to obtain a better development of reservoirs placed in thin layers of sandstone. In this scenario, several challenges are faced when drilling in deep water. The traditional approach for predicting instabilities is to determine collapses and fractures at borehole wall. However, the initiation of rupture does not indicate that the borehole fails to perform its function as a wellbore. Thus, a methodology in which the stability window may be enlarged is desirable. This paper presents one practical analytical methodology that consists in allowing wellbore pressures smaller than the conventional collapse pressure, i.e., based upon failure on the borehole wall. This means that a collapse region (shear failure) will be developed around the borehole wall. This collapse region is pre-defined and to estimate its size is used a failure criterion. The aforementioned methodology is implemented in a user-friendly software, which can perform analyses of stress, pore pressure, formation failure, mud weight and mud salinity design for drilling in shale formations. Simulations of a wellbore drilling in a narrow stability window environment are performed to demonstrate the improvements of using the methodology. (author)

  4. Narrow resonances and short-range interactions

    Gelman, Boris A.

    2009-01-01

    Narrow resonances in systems with short-range interactions are discussed in an effective field theory (EFT) framework. An effective Lagrangian is formulated in the form of a combined expansion in powers of a momentum Q 0 | 0 --a resonance peak energy. At leading order in the combined expansion, a two-body scattering amplitude is the sum of a smooth background term of order Q 0 and a Breit-Wigner term of order Q 2 (δε) -1 which becomes dominant for δε 3 . Such an EFT is applicable to systems in which short-distance dynamics generates a low-lying quasistationary state. The EFT is generalized to describe a narrow low-lying resonance in a system of charged particles. It is shown that in the case of Coulomb repulsion, a two-body scattering amplitude at leading order in a combined expansion is the sum of a Coulomb-modified background term and a Breit-Wigner amplitude with parameters renormalized by Coulomb interactions.

  5. Role of paramagnetic chromium in chromium(VI)-induced damage in cultured mammalian cells.

    Sugiyama, M

    1994-01-01

    Chromium(VI) compounds are known to be potent toxic and carcinogenic agents. Because chromium(VI) is easily taken up by cells and is subsequently reduced to chromium(III), the formation of paramagnetic chromium such as chromium(V) and chromium(III) is believed to play a role in the adverse biological effects of chromium(VI) compounds. The present report, uses electron spin resonance (ESR) spectroscopy; the importance of the role of paramagnetic chromium in chromium(VI)-induced damage in intac...

  6. Measurement of electron paramagnetic resonance using terahertz time-domain spectroscopy.

    Kozuki, Kohei; Nagashima, Takeshi; Hangyo, Masanori

    2011-12-05

    We present a frequency-domain electron spin resonance (ESR) measurement system using terahertz time-domain spectroscopy. A crossed polarizer technique is utilized to increase the sensitivity in detecting weak ESR signals of paramagnets caused by magnetic dipole transitions between magnetic sublevels. We demonstrate the measurements of ESR signal of paramagnetic copper(II) sulfate pentahydrate with uniaxial anisotropy of the g-factor under magnetic fields up to 10 T. The lineshape of the obtained ESR signals agrees well with the theoretical predictions for a powder sample with the uniaxial anisotropy.

  7. Pauli Paramagnetic Susceptibility of an Ideal Anyon Gas within Haldane Fractional Exclusion Statistics

    Qin Fang; Chen Jisheng

    2012-01-01

    The finite-temperature Pauli paramagnetic susceptibility of a three-dimensional ideal anyon gas obeying Haldane fractional exclusion statistics is studied analytically. Different from the result of an ideal Fermi gas, the susceptibility of an ideal anyon gas depends on a statistical factor g in Haldane statistics model. The low-temperature and high-temperature behaviors of the susceptibility are investigated in detail. The Pauli paramagnetic susceptibility of the two-dimensional ideal anyons is also derived. It is found that the reciprocal of the susceptibility has the similar factorizable property which is exhibited in some thermodynamic quantities in two dimensions.

  8. Design of narrow band photonic filter with compact MEMS for tunable resonant wavelength ranging 100 nm

    Guanquan Liang

    2011-12-01

    Full Text Available A prototype of planar silicon photonic structure is designed and simulated to provide narrow resonant line-width (∼2 nm in a wide photonic band gap (∼210 nm with broad tunable resonant wavelength range (∼100 nm around the optical communication wavelength 1550 nm. This prototype is based on the combination of two modified basic photonic structures, i.e. a split tapered photonic crystal micro-cavity embedded in a photonic wire waveguide, and a slot waveguide with narrowed slabs. This prototype is then further integrated with a MEMS (microelectromechanical systems based electrostatic comb actuator to achieve “coarse tune” and “fine tune” at the same time for wide range and narrow-band filtering and modulating. It also provides a wide range tunability to achieve the designed resonance even fabrication imperfection occurs.

  9. Large bandgap narrowing in rutile TiO2 aimed towards visible light applications and its correlation with vacancy-type defects history and transformation

    Nair, Radhika V.; Gayathri, P. K.; Siva Gummaluri, Venkata; Nambissan, P. M. G.; Vijayan, C.

    2018-01-01

    Extension of photoactivity of TiO2 to the visible region is achievable via effective control over the intrinsic defects such as oxygen and Ti vacancies, which has several applications in visible photocatalysis and sensing. We present here the first observation of an apparent bandgap narrowing and bandgap tuning effect due to vacancy cluster transformation in rutile TiO2 structures to 1.84 eV from the bulk bandgap of 3 eV. A gradual transformation of divacancies (V Ti-O) to tri vacancies ({{V}Ti-O-T{{i-}}} ) achieved through a controlled solvothermal scheme appears to result in an apparent narrowing bandgap and tunability, as supported by positron annihilation lifetime and electron paramagnetic resonance spectroscopy measurements. Visible photocatalytic activity of the samples is demonstrated in terms of photodegradation of rhodamine B dye molecules.

  10. Experimental and computational approaches to evaluate the environmental mitigation effect in narrow spaces by noble metal chemical addition (NMCA)

    Shimizu, Ryosuke; Ota, Nobuyuki; Nagase, Makoto; Aizawa, Motohiro; Ishida, Kazushige; Wada, Yoichi

    2014-01-01

    The environmental mitigation effect of NMCA in a narrow space was evaluated by experimental and computational approaches. In the experiment at 8 MPa and 553K, T-tube whose branched line had a narrow space was prepared, and the Zr electrodes were set in the branched line at certain intervals, which were 1, 3, 5, 7, 9, 11, 15 and 29 cm from the opening section of the branched line. Electrochemical corrosion potential (ECP) at the tip of the branched narrow space varied in response to the water chemistry in the main line which was at right angle with the branched line. Computational fluid dynamics (CFD) analysis reproduced the experimental results. It was also confirmed by CFD analysis that the ingress of water from the main line into the narrow space was accelerated by cavity flow and thermal convection. By CFD analysis in a thermal sleeve of actual plant condition, which had a narrow space, the concentration of dissolved oxygen at a tip of the thermal sleeve reached at 250 ppb within 300 sec, which was the same concentration of the main line. Noble metal deposition on the surface of the thermal sleeve was evaluated by mass transfer model. Noble metal deposition was the largest near the opening section of the branched line, and gradually decreased toward the tip section. In light of the consumption of dissolved oxygen in the branched line, noble metal deposition in the thermal sleeve was sufficient to reduce the ECP. It was expected that NMCA could mitigate the corrosion environment in the thermal sleeve. (author)

  11. Detection of Bacillus anthracis spores by super-paramagnetic lateral-flow immunoassays based on "Road Closure".

    Wang, Dian-Bing; Tian, Bo; Zhang, Zhi-Ping; Wang, Xu-Ying; Fleming, Joy; Bi, Li-Jun; Yang, Rui-Fu; Zhang, Xian-En

    2015-05-15

    Detection of Bacillus anthracis in the field, whether as a natural infection or as a biothreat remains challenging. Here we have developed a new lateral-flow immunochromatographic assay (LFIA) for B. anthracis spore detection based on the fact that conjugates of B. anthracis spores and super-paramagnetic particles labeled with antibodies will block the pores of chromatographic strips and form retention lines on the strips, instead of the conventionally reported test lines and control lines in classic LFIA. As a result, this new LFIA can simultaneously realize optical, magnetic and naked-eye detection by analyzing signals from the retention lines. As few as 500-700 pure B. anthracis spores can be recognized with CV values less than 8.31% within 5 min of chromatography and a total time of 20 min. For powdery sample tests, this LFIA can endure interference from 25% (w/v) milk, 10% (w/v) baking soda and 10% (w/v) starch without any sample pre-treatment, and has a corresponding detection limit of 6×10(4) spores/g milk powder, 2×10(5) spores/g starch and 5×10(5) spores/g baking soda. Compared with existing methods, this new approach is very competitive in terms of sensitivity, specificity, cost and ease of operation. This proof-of-concept study can also be extended for detection of many other large-sized analytes. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Analysis of narrow effects in pp annihilations

    Defoix, C

    1972-01-01

    The author describes briefly some methods of analysis that final states involving a number of like particles require. A first method consists of separating two competing channels to minimize the reflections due to the undesirable one. Later techniques of analysis lead to the isolation of the only channel of interest and circumvention of the problems of background and reflections due to irrelevant final states. Generally, all these processes are based on the presence of a narrow and identified resonance, for example the eta /sup 0/ or omega /sup 0/ ( to pi /sup +/ pi /sup -/ pi /sup 0/). To be efficient, it is necessary that the observed width of such a basic resonance not be increased too much by experimental errors. (6 refs).

  13. Search for narrow four-baryon states

    Badelek, B.

    1981-01-01

    Highly excited (4.10 2 ) four-baryon resonances have been searched for in the missing-mass spectrum of the reaction π - + 4 He → π - + X at 5 GeV/c in the region of small four-momentum transfer (0.005 2 ), where one of the decay products of the X is either proton or deuteron or triton. No resonance signal is seen in the mass spectrum of X. Within our limited acceptance, the cross section for the production of a narrow (GAMMA approx. 20 MeV/c 2 ) four-baryon state with mass 4.9 GeV/c 2 is estimated to be smaller than approx. 100 nb. (orig.)

  14. Active Brownian motion in a narrow channel

    Ao, X.; Ghosh, P. K.; Li, Y.; Schmid, G.; Hänggi, P.; Marchesoni, F.

    2014-12-01

    We review recent advances in rectification control of artificial microswimmers, also known as Janus particles, diffusing along narrow, periodically corrugated channels. The swimmer self-propulsion mechanism is modeled so as to incorporate a nonzero torque (propulsion chirality). We first summarize the effects of chirality on the autonomous current of microswimmers freely diffusing in channels of different geometries. In particular, left-right and upside-down asymmetric channels are shown to exhibit different transport properties. We then report new results on the dependence of the diffusivity of chiral microswimmers on the channel geometry and their own self-propulsion mechanism. The self-propulsion torque turns out to play a key role as a transport control parameter.

  15. The effect of narrow provider networks on health care use.

    Atwood, Alicia; Lo Sasso, Anthony T

    2016-12-01

    Network design is an often overlooked aspect of health insurance contracts. Recent policy factors have resulted in narrower provider networks. We provide plausibly causal evidence on the effect of narrow network plans offered by a large national health insurance carrier in a major metropolitan market. Our econometric design exploits the fact that some firms offer a narrow network plan to their employees and some do not. Our results show that narrow network health plans lead to reductions in health care utilization and spending. We find evidence that narrow networks save money by selecting lower cost providers into the network. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. The mean-size dependence of the exchange narrowing in molecular J-aggregates

    Chen Yulu; Zhao Jijun

    2011-01-01

    The effect of segment-size fluctuations on exchange narrowing in a molecular J-aggregate of site-energy disordered distributions is studied using a one-dimensional Frenkel-exciton model. It is found that the segment-size disorder leads to the width of the absorption spectra deviating from the scaling law, σ 4/3 of the site-energy disordered standard deviation σ, being suitable for the system only with the site-energy disorder. In larger σ, the segment-size disorder has little influence on the linear absorption spectra. With increasing segment mean-length, the absorption line width monotonically increases, and then approaches a saturated value. By comparing a system of larger mean-length segment with a smaller one, both with the same segment-size disorder, it is found that the absorption line width of the former is broadened, and the exchange narrowing effect is reduced. The present result shows that the correlation effect can be partially maintained for the system with larger mean-length segment. -- Research Highlights: → Segment fluctuations affect the exchange narrowing of molecular J-aggregates. → The width of the absorption spectra is found to deviate from the scaling law. → Increase in segment size causes increase in the width and then saturates. → Exchange narrowing is reduced for larger mean-size segment. → Correlation can be kept partly in the larger size segment.

  17. EPR- study of paramagnetic features of brown coal from Kiyakty coal deposit after mechanic activation and electron irradiation

    Ryabikin, Yu.A.; Zashkvara, O.V.; Popov, S.N.; Kairbekov, Zh.K.; Ershova, Zh.R.; Kupchishin, A.I.; Kovtunets, V.A.

    2003-01-01

    Full text: It is known that prospected coal resources exceed, at least by order of magnitude, petroleum reserves decreasing steeply at last time as a result of world oil consumption rise. In this connection the manufacture of different liquid products from coal, especially brown coal, is issue of the day. Liquid fuel yield depends on physical-chemical characteristics and their changes owing to preliminary chemical, mechanical and radiation treatment. In this paper some results of paramagnetic characteristic study of Kiyakty deposit coal as initial one as after its mechanical treatment and electron irradiation are presented. It is discovered that in Kiyakty coal there are, at least, two fractions differed in EPR line width and concentration of free radical states they contained. First fraction has EPR line width ΔH 1 =4-5 Oe and mean free radical states concentration N 1 = 2.4·10 17 sp/g. For samples of second fraction the EPR line width ΔH 2 = 6.6-7.2 Oe and N 2 = 1.8·10 18 sp/g are typical. Thus, in the second fraction the EPR line width and free radical states concentration are greater than in the first case. Besides free radical states in coal EPR signals were found from trivalent iron ions with g-factor approximated 2 and with g=4.3. It the signals with g=4.3, are practically identical for both fractions, their concentrations are neighbour and line width is ΔH 1 = 250 Oe, then for the lines near g=2.0 situation is markedly different. For the first fraction ΔH 1 = 800 Oe whereas for the second case two signals in this g-factor range are observed. The first signal has line width ΔH 1 = 550 Oe and g=l .97, the second is more wide with ΔH 1 = 1000 Oe and g=2.02. We cannot discover significant dependence of free radical states concentration on mechanic activation time. Obviously, life times of complementary free radical states generated in process of coal activation are very low. As Fe 3+ ions, for both fractions it is observed intensity growth of their

  18. Pauli paramagnetic effects on vortices in superconducting TmNi2B2C

    DeBeer-Schmitt, L.; Eskildsen, Morten Ring; Ichioka, M.

    2007-01-01

    The magnetic field distribution around the vortices in TmNi2B2C in the paramagnetic phase was studied experimentally as well as theoretically. The vortex form factor, measured by small-angle neutron scattering, is found to be field independent up to 0.6H(c2) followed by a sharp decrease at higher...

  19. Contribution of electron paramagnetic resonance to the studies of hemoglobin: the nitrosylhemoglobin system

    Bemski, G.

    1995-03-01

    Since the initial work of Ingram Electron Paramagnetic Resonance contributed considerably to research in hemoglobins. Now, 40 years later some of the results of the application of EPR to nitrosyl hemoglobin (HbNO), are reviewed as an example of the diversity of information which this technique can provide are reviewed. (author). 34 refs, 7 figs

  20. Paramagnetic NMR investigation of dendrimer-based host-guest interactions.

    Fei Wang

    Full Text Available In this study, the host-guest behavior of poly(amidoamine (PAMAM dendrimers bearing amine, hydroxyl, or carboxylate surface functionalities were investigated by paramagnetic NMR studies. 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO derivatives were used as paramagnetic guest molecules. The results showed that TEMPO-COOH significantly broaden the ¹H NMR peaks of amine- and hydroxyl-terminated PAMAM dendrimers. In comparison, no paramagnetic relaxation enhancement (PRE was observed between TEMPO-NH₂, TEMPO-OH and the three types of PAMAM dendrimers. The PRE phenomenon observed is correlated with the encapsulation of TEMPO-COOH within dendrimer pockets. Protonation of the tertiary amine groups within PAMAM dendrimers plays an important role during this process. Interestingly, the absence of TEMPO-COOH encapsulation within carboxylate-terminated PAMAM dendrimer is observed due to the repulsion of TEMPO-COO- anion and anionic dendrimer surface. The combination of paramagnetic probes and ¹H NMR linewidth analysis can be used as a powerful tool in the analysis of dendrimer-based host-guest systems.

  1. Clean bulk YBaCuO superconductors doped by paramagnetic ions of Sm and Yb

    Jirsa, Miloš; Volochová, D.; Kováč, J.; Diko, P.

    2017-01-01

    Roč. 131, č. 4 (2017), s. 1027-1029 ISSN 0587-4246 Institutional support: RVO:68378271 Keywords : YBaCuO * bulk superconductors * paramagnetic ions * microstructure * vortex pinning Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 0.469, year: 2016

  2. Study of the arrangement of crystallites in γ-irradiated human enamel by electron paramagnetic resonance

    Cevc, P.; Schara, M.; Ravnik, C.; Skaleric, U.

    1976-01-01

    The arrangement of tooth enamel microcrystals has been studied on CO 3 3- bound electrons by paramagnetic resonance. It was found that noncarious human maxillary central incisors have a greater degree of alignment of tooth enamel microcrystals than the carious ones. The outermost surface layer of enamel showed a greater crystallite degree of alignment than other parts

  3. Effect of paramagnetic manganese cations on H-1 MRS of the brain

    Madsen, K. S.; Holm, David Alberg; Søgaard, L. V.

    2008-01-01

    Manganese cations (Mn2+) call be used as all intracellular contrast agent for structural, functional and neural pathway imaging applications. However, at high concentrations, Mn2+ is neurotoxic and play influence the concentration of H-1 MR-detectable metabolites. Furthermore, the paramagnetic Mn...

  4. Concentration of paramagnetic centres at low-temperature thermal destruction of asphaltenes of heavy petroleum distillates

    Dolomatov M.U., Rodionov A.A., Gafurov M.R., Petrov A.V., Biktagirov T.B., Bakhtizin R.Z., Makarchikov S.O., Khairudinov I.Z., Orlinskii S.B.

    2016-11-01

    Full Text Available Changes of paramagnetic centers (PC concentration in dispersed petroleum systems were studied in the process of low-temperature thermolysis. The kinetic model of PC concentration dynamics based on the processes of unpaired electrons formation during singlet-triplet transitions, weak chemical bonds dissociation and recombination of free radicals is proposed.

  5. Identification and Quantification of Copper Sites in Zeolites by Electron Paramagnetic Resonance Spectroscopy

    Godiksen, Anita; Vennestrøm, Peter N. R.; Rasmussen, Søren Birk

    2017-01-01

    Recent quantitative electron paramagnetic resonance spectroscopy (EPR) data on different copper species present in copper exchanged CHA zeolites are presented and put into context with the literature on other copper zeolites. Results presented herein were obtained using ex situ and in situ EPR...

  6. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers

    Chu, Shidong; Maltsev, Sergey B.; Emwas, Abdul-Hamid M.; Lorigan, Gary A.

    2010-01-01

    A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2

  7. Electron Paramagnetic Resonance and X-ray Diffraction of Boron- and Phosphorus-Doped Nanodiamonds

    Binh, Nguyen Thi Thanh; Dolmatov, V. Yu.; Lapchuk, N. M.; Shymanski, V. I.

    2017-11-01

    Powders of boron- and phosphorus-doped detonation nanodiamonds and sintered pellets of non-doped nanodiamond powders were studied using electron paramagnetic resonance and x-ray diffraction. Doping of detonation nanodiamond crystals with boron and phosphorus was demonstrated to be possible. These methods could be used to diagnose diamond nanocrystals doped during shock-wave synthesis.

  8. Stokes line width

    Nikiskov, A.I.; Ritus, V.I.

    1993-01-01

    The concept of Stokes line width is introduced for the asymptotic expansions of functions near an essential singularity. Explicit expressions are found for functions (switching functions) that switch on the exponentially small terms for the Dawson integral, Airy function, and the gamma function. A different, more natural representation of a function, not associated with expansion in an asymptotic series, in the form of dominant and recessive terms is obtained by a special division of the contour integral which represents the function into contributions of higher and lower saddle points. This division leads to a narrower, natural Stokes line width and a switching function of an argument that depends on the topology of the lines of steepest descent from the saddle point

  9. Experimental studies of x-ray laser spectral profiles: Observation of gain narrowing and saturation behavior

    Koch, J.A.; MacGowan, B.J.; Da Silva, L.B.; Matthews, D.L.; Mrowka, S.; Underwood, J.H.; Batson, P.J.

    1992-01-01

    We discuss our recent measurements of the spectral width of the 206.38 Angstrom x-ray laser transition in Ne-like Se. These measurements used a high-resolution grating spectrometer and were performed over a wide range of laser amplifier lengths. The data have enabled us to extrapolate the intrinsic line width and to observe the effects of gain-narrowing and saturation on the line profile. We find an intrinsic width which is 1.4 times the Doppler width, we observe gain-narrowing in intermediate length amplifiers, and we observe no re-broadening in long, saturated amplifiers. These results suggest that collisional line-broadening has a significant effect on the line profile and saturation behavior of this laser. We discuss modeling we have performed in order to simulate the experimental data, and we discuss future experimental and theoretical efforts we believe are necessary in order to understand line broadening and line transfer issues in x-ray laser plasmas

  10. Absorptive reduction and width narrowing in λ-type atoms confined between two dielectric walls

    Li Yuanyuan; Hou Xun; Bai Jintao; Yan Junfeng; Gan Chenli; Zhang Yanpeng

    2008-01-01

    This paper investigates the absorptive reduction and the width narrowing of electromagnetically induced transparency (EIT) in a thin vapour film of λ-type atoms confined between two dielectric walls whose thickness is comparable with the wavelength of the probe field. The absorptive lines of the weak probe field exhibit strong reductions and very narrow EIT dips, which mainly results from the velocity slow-down effects and transient behaviour of atoms in a confined system. It is also shown that the lines are modified by the strength of the coupling field and the ratio of L/λ, with L the film thickness and λ the wavelength of the probe field. A simple robust recipe for EIT in a thin medium is achievable in experiment. (general)

  11. A solution for the narrow rectangular punch

    Panek, C.F.; Kalker, J.J.

    1977-01-01

    This paper considers the problem of a rectangular flat ended punch acting on an elastic half-space. An approximate solution is generated through application of the elastic line integral equations. The results produced by this method are then compared with another approximate solution already

  12. Impurity-induced photoconductivity of narrow-gap Cadmium–Mercury–Telluride structures

    Kozlov, D. V., E-mail: dvkoz@impras.ru; Rumyantsev, V. V.; Morozov, S. V.; Kadykov, A. M. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Varavin, V. S.; Mikhailov, N. N.; Dvorestky, S. A. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gavrilenko, V. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Teppe, F. [Universite Montpellier II, Laboratoire Charles Coulomb (L2C) (France)

    2015-12-15

    The photoconductivity (PC) spectra of CdHgTe (MCT) solid solutions with a Cd fraction of 17 and 19% are measured. A simple model for calculating the states of doubly charged acceptors in MCT solid solutions, which makes it possible to describe satisfactorily the observed photoconductivity spectra, is proposed. The found lines in the photoconductivity spectra of narrow-gap MCT structures are associated with transitions between the states of both charged and neutral acceptor centers.

  13. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    Javier-Ccallata, Henry; Filho, Luiz Tomaz; Sartorelli, Maria L.; Watanabe, Shigueo

    2013-01-01

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe 2+ and Fe 3+ . •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe 3+ . -- Abstract: Natural silicate mineral of pumpellyite, Ca 2 MgAl 2 (SiO 4 )(Si 2 O 7 )(OH) 2 ·(H 2 O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe 2+ and Fe 3+ . The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe 2+ → e − + Fe 3+ . On the other hand, EPR measurements reveal six lines of Mn 2+ , and satellites due to hyperfine interaction, superimposed on the signal of Fe 3+ around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe 3+ hides all Mn 2+ lines. The strong growth of this signal indicates that the transitions are due to Fe 3+ dipole–dipole interactions

  14. Effects of pre-irradiation annealing at high temperature on optical absorption and electron paramagnetic resonance of natural pumpellyite mineral

    Javier-Ccallata, Henry, E-mail: henrysjc@gmail.com [Escuela de Ingeniería Electrónica y Telecomunicaciones, Universidad Alas Peruanas Filial Arequipa, Urb. D. A. Carrión G-14, J. L. Bustamante y Rivero, Arequipa (Peru); Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Filho, Luiz Tomaz [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil); Faculdade de Tecnologia e Ciências Exatas, Universidade São Judas Tadeu, Rua Taquari 546, São Paulo, SP (Brazil); Sartorelli, Maria L. [Laboratório de Sistemas Nanoestruturados, Departamento de Física, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina (Brazil); Watanabe, Shigueo [Departamento de Física Nuclear, Instituto de Física, Universidade de São Paulo, Rua do Matão, travessa R, 187, CEP 05508-900 São Paulo, SP (Brazil)

    2013-09-15

    Highlights: •Natural pumpellyite mineral presents superposition bands around 900 and 1060 nm due Fe{sup 2+}and Fe{sup 3+}. •High temperature annealing influences the EPR and OA spectra. •The behavior of EPR line for 800 and 900 °C can be attributed to forbidden dd transitions due the Fe{sup 3+}. -- Abstract: Natural silicate mineral of pumpellyite, Ca{sub 2}MgAl{sub 2}(SiO{sub 4})(Si{sub 2}O{sub 7})(OH){sub 2}·(H{sub 2}O), point group A2/m, has been studied concerning high temperature annealing and γ-radiation effects on Optical Absorption (OA) and Electron Paramagnetic Resonance (EPR) properties. Chemical analysis revealed that besides Si, Al, Ca and Mg, other oxides i.e., Fe, Mn, Na, K, Ti and P are present in the structure as impurities. OA measurements of natural and annealed pumpellyite revealed several bands in the visible region due to spin forbidden transitions of Fe{sup 2+} and Fe{sup 3+}. The behaviour of bands around 900 and 1060 nm, with pre-annealing and γ radiation dose, indicating a transition Fe{sup 2+} → e{sup −} + Fe{sup 3+}. On the other hand, EPR measurements reveal six lines of Mn{sup 2+}, and satellites due to hyperfine interaction, superimposed on the signal of Fe{sup 3+} around of g = 2. For heat treatment from 800 °C the signal grows significantly and for 900 °C a strong signal of Fe{sup 3+} hides all Mn{sup 2+} lines. The strong growth of this signal indicates that the transitions are due to Fe{sup 3+} dipole–dipole interactions.

  15. Thermal tuning On narrow linewidth fiber laser

    Han, Peiqi; Liu, Tianshan; Gao, Xincun; Ren, Shiwei

    2010-10-01

    At present, people have been dedicated to high-speed and large-capacity optical fiber communication system. Studies have been shown that optical wavelength division multiplexing (WDM) technology is an effective means of communication to increase the channel capacity. Tunable lasers have very important applications in high-speed, largecapacity optical communications, and distributed sensing, it can provide narrow linewidth and tunable laser for highspeed optical communication. As the erbium-doped fiber amplifier has a large gain bandwidth, the erbium-doped fiber laser can be achieved lasing wavelength tunable by adding a tunable filter components, so tunable filter device is the key components in tunable fiber laser.At present, fiber laser wavelength is tuned by PZT, if thermal wavelength tuning is combined with PZT, a broader range of wavelength tuning is appearance . Erbium-doped fiber laser is used in the experiments,the main research is the physical characteristics of fiber grating temperature-dependent relationship and the fiber grating laser wavelength effects. It is found that the fiber laser wavelength changes continuously with temperature, tracking several temperature points observed the self-heterodyne spectrum and found that the changes in spectra of the 3dB bandwidth of less than 1kHz, and therefore the fiber laser with election-mode fiber Bragg grating shows excellent spectral properties and wavelength stability.

  16. Recovering physical properties from narrow-band photometry

    Schoenell, W.; Cid Fernandes, R.; Benítez, N.; Vale Asari, N.

    2013-05-01

    Our aim in this work is to answer, using simulated narrow-band photometry data, the following general question: What can we learn about galaxies from these new generation cosmological surveys? For instance, can we estimate stellar age and metallicity distributions? Can we separate star-forming galaxies from AGN? Can we measure emission lines, nebular abundances and extinction? With what precision? To accomplish this, we selected a sample of about 300k galaxies with good S/N from the SDSS and divided them in two groups: 200k objects and a template library of 100k. We corrected the spectra to z = 0 and converted them to filter fluxes. Using a statistical approach, we calculated a Probability Distribution Function (PDF) for each property of each object and the library. Since we have the properties of all the data from the STARLIGHT-SDSS database, we could compare them with the results obtained from summaries of the PDF (mean, median, etc). Our results shows that we retrieve the weighted average of the log of the galaxy age with a good error margin (σ ≈ 0.1 - 0.2 dex), and similarly for the physical properties such as mass-to-light ratio, mean stellar metallicity, etc. Furthermore, our main result is that we can derive emission line intensities and ratios with similar precision. This makes this method unique in comparison to the other methods on the market to analyze photometry data and shows that, from the point of view of galaxy studies, future photometric surveys will be much more useful than anticipated.

  17. From Narrow to Wide Band Normalizer for LHC

    Vismara, Giuseppe

    1997-01-01

    The narrow band normalizer (NBN) based on the phase processor is working to full satisfaction in the LEP BOM system for almost 10 years. Recently a new idea for a wide band normaliser (WBN) based on a time processor exploiting a single oscillation period has been developed. The position information is converted into a time difference between the zero crossing of two recombined and shaped electrode signals. It appears that the NBN can be easily adapted to perform as a wide band processor. To do so, the BP filter and the 90° Hybrid are replaced by low pass filter and delay lines. A prototype based on the present NBN has been developed and tested to prove the feasibility of the new idea. The paper gives an overview of the advantages and limitations of the BOM NB processor. It summarizes the useful LHC parameters and describes the specifications for the beam position acquisition system. After describing the basic principles, it analyzes in detail all the blocks of the processing chain and presents the measurem...

  18. Extreme ultraviolet narrow band emission from electron cyclotron resonance plasmas

    Zhao, H. Y.; Zhao, H. W.; Sun, L. T.; Zhang, X. Z.; Wang, H.; Ma, B. H.; Li, X. X.; Zhu, Y. H.; Sheng, L. S.; Zhang, G. B.; Tian, Y. C.

    2008-01-01

    Extreme ultraviolet lithography (EUVL) is considered as the most promising solution at and below dynamic random access memory 32 nm half pitch among the next generation lithography, and EUV light sources with high output power and sufficient lifetime are crucial for the realization of EUVL. However, there is no EUV light source completely meeting the requirements for the commercial application in lithography yet. Therefore, ECR plasma is proposed as a novel concept EUV light source. In order to investigate the feasibility of ECR plasma as a EUV light source, the narrow band EUV power around 13.5 nm emitted by two highly charged ECR ion sources--LECR2M and SECRAL--was measured with a calibrated EUV power measurement tool. Since the emission lines around 13.5 nm can be attributed to the 4d-5p transitions of Xe XI or the 4d-4f unresolved transition array of Sn VIII-XIII, xenon plasma was investigated. The dependence of the EUV throughput and the corresponding conversion efficiency on the parameters of the ion source, such as the rf power and the magnetic confinement configurations, were preliminarily studied

  19. Spectral narrowing of a 980 nm tapered diode laser bar

    Vijayakumar, Deepak; Jensen, Ole Bjarlin; Lucas Leclin, Ga"lle; Petersen, Paul Michael; Thestrup, Birgitte

    2011-03-01

    High power diode laser bars are interesting in many applications such as solid state laser pumping, material processing, laser trapping, laser cooling and second harmonic generation. Often, the free running laser bars emit a broad spectrum of the order of several nanometres which limit their scope in wavelength specific applications and hence, it is vital to stabilize the emission spectrum of these devices. In our experiment, we describe the wavelength narrowing of a 12 element 980 nm tapered diode laser bar using a simple Littman configuration. The tapered laser bar which suffered from a big smile has been "smile corrected" using individual phase masks for each emitter. The external cavity consists of the laser bar, both fast and slow axis micro collimators, smile correcting phase mask, 6.5x beam expanding lens combination, a 1200 lines/mm reflecting grating with 85% efficiency in the first order, a slow axis focusing cylindrical lens of 40 mm focal length and an output coupler which is 10% reflective. In the free running mode, the laser emission spectrum was 5.5 nm wide at an operating current of 30A. The output power was measured to be in excess of 12W. Under the external cavity operation, the wavelength spread of the laser could be limited to 0.04 nm with an output power in excess of 8 W at an operating current of 30A. The spectrum was found to be tuneable in a range of 16 nm.

  20. Effect of regulatory architecture on broad versus narrow sense heritability.

    Yunpeng Wang

    Full Text Available Additive genetic variance (VA and total genetic variance (VG are core concepts in biomedical, evolutionary and production-biology genetics. What determines the large variation in reported VA /VG ratios from line-cross experiments is not well understood. Here we report how the VA /VG ratio, and thus the ratio between narrow and broad sense heritability (h(2 /H(2 , varies as a function of the regulatory architecture underlying genotype-to-phenotype (GP maps. We studied five dynamic models (of the cAMP pathway, the glycolysis, the circadian rhythms, the cell cycle, and heart cell dynamics. We assumed genetic variation to be reflected in model parameters and extracted phenotypes summarizing the system dynamics. Even when imposing purely linear genotype to parameter maps and no environmental variation, we observed quite low VA /VG ratios. In particular, systems with positive feedback and cyclic dynamics gave more non-monotone genotype-phenotype maps and much lower VA /VG ratios than those without. The results show that some regulatory architectures consistently maintain a transparent genotype-to-phenotype relationship, whereas other architectures generate more subtle patterns. Our approach can be used to elucidate these relationships across a whole range of biological systems in a systematic fashion.

  1. Optimized co-solute paramagnetic relaxation enhancement for the rapid NMR analysis of a highly fibrillogenic peptide

    Oktaviani, Nur Alia; Risør, Michael W.; Lee, Young-Ho; Megens, Rik P.; Jong, Djurre H. de; Otten, Renee; Scheek, Ruud M.; Enghild, Jan J.; Nielsen, Niels Chr.; Ikegami, Takahisa; Mulder, Frans A. A.

    2015-01-01

    Co-solute paramagnetic relaxation enhancement (PRE) is an attractive way to speed up data acquisition in NMR spectroscopy by shortening the T 1 relaxation time of the nucleus of interest and thus the necessary recycle delay. Here, we present the rationale to utilize high-spin iron(III) as the optimal transition metal for this purpose and characterize the properties of its neutral chelate form Fe(DO3A) as a suitable PRE agent. Fe(DO3A) effectively reduces the T 1 values across the entire sequence of the intrinsically disordered protein α-synuclein with negligible impact on line width. The agent is better suited than currently used alternatives, shows no specific interaction with the polypeptide chain and, due to its high relaxivity, is effective at low concentrations and in ‘proton-less’ NMR experiments. By using Fe(DO3A) we were able to complete the backbone resonance assignment of a highly fibrillogenic peptide from α 1 -antitrypsin by acquiring the necessary suite of multidimensional NMR datasets in 3 h

  2. Optimized co-solute paramagnetic relaxation enhancement for the rapid NMR analysis of a highly fibrillogenic peptide

    Oktaviani, Nur Alia [University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute (Netherlands); Risør, Michael W. [University of Aarhus, Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry (Denmark); Lee, Young-Ho [Osaka University, Institute for Protein Research (Japan); Megens, Rik P. [University of Groningen, Stratingh Institute for Chemistry (Netherlands); Jong, Djurre H. de; Otten, Renee; Scheek, Ruud M. [University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute (Netherlands); Enghild, Jan J. [University of Aarhus, Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics (Denmark); Nielsen, Niels Chr. [University of Aarhus, Interdisciplinary Nanoscience Center (iNANO) and Department of Chemistry (Denmark); Ikegami, Takahisa [Yokohama City University, Graduate School of Medical Life Science (Japan); Mulder, Frans A. A., E-mail: fmulder@chem.au.dk [University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute (Netherlands)

    2015-06-15

    Co-solute paramagnetic relaxation enhancement (PRE) is an attractive way to speed up data acquisition in NMR spectroscopy by shortening the T{sub 1} relaxation time of the nucleus of interest and thus the necessary recycle delay. Here, we present the rationale to utilize high-spin iron(III) as the optimal transition metal for this purpose and characterize the properties of its neutral chelate form Fe(DO3A) as a suitable PRE agent. Fe(DO3A) effectively reduces the T{sub 1} values across the entire sequence of the intrinsically disordered protein α-synuclein with negligible impact on line width. The agent is better suited than currently used alternatives, shows no specific interaction with the polypeptide chain and, due to its high relaxivity, is effective at low concentrations and in ‘proton-less’ NMR experiments. By using Fe(DO3A) we were able to complete the backbone resonance assignment of a highly fibrillogenic peptide from α{sub 1}-antitrypsin by acquiring the necessary suite of multidimensional NMR datasets in 3 h.

  3. Electron paramagnetic resonance evidence of hydroxyl radical generation and oxidative damage induced by tetrabromobisphenol A in Carassius auratus

    Shi Huahong [State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China)]. E-mail: huahongshi@tom.com; Wang Xiaorong [State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China); Luo Yi [State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China); Su Yan [State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing 210093 (China)

    2005-09-30

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants (BFRs). To confirm its putative oxidative stress-inducing activity, freshwater fish Carassius auratus were injected intraperitoneally with TBBPA. One experiment lasted 3 h to 28 days after a single injection of 100 mg/kg TBBPA, and the other lasted 24 h after a single injection of 0-300 mg/kg TBBPA. Reactive oxygen species (ROS) were trapped by phenyl-tert-butyl nitrone (PBN) and detected by electron paramagnetic resonance (EPR). Protein carbonyl (PCO) and lipid peroxidation product (LPO) content were also determined. A six-line EPR spectrum was detected in the sample prepared in air, and a multiple one was obtained in nitrogen. The observed spectrum in nitrogen fits the simulation one with PBN/{center_dot}OCH{sub 3} and PBN/{center_dot}CH{sub 3} quite well. As compared to the control group, TBBPA significantly induced ROS production marked by the intensity of the prominent spectra in liver and bile. TBBPA (100 mg/kg) also significantly increased PCO content in liver starting 24 h and LPO content 3 days after injection. Either PCO or LPO content showed significant relation with ROS production. Based on the hyperfine constants and shape of the spectrum, ROS induced by TBBPA was determined as {center_dot}OH. The results clearly indicated that TBBPA could induce {center_dot}OH generation and result in oxidative damage in liver of C. auratus.

  4. Paramagnetism and magnetic relaxation in melt-textured grown GdBa2Cu3O6+y

    Qin, M.J.; Fu, X.K.; Ren, H.T.

    1996-01-01

    Magnetic measurements have been performed on a melt-textured grown (MTG) GdBa 2 Cu 3 O 6+y sample. Because of the paramagnetism of the Gd 3+ ions, the magnetization relaxation rate is increased by a factor of 4πχ. The effect of paramagnetism on the U(J) relationship of the sample has also been discussed. At the end, we extraxted the U(J) relationship based on the field sweep rate H, which is in agreement with the one after corrections for paramagnetism. (orig.)

  5. Narrow Networks on the Individual Marketplace in 2017.

    Polski, Daniel; Weiner, Janet; Zhang, Yuehan

    2017-09-01

    This Issue Brief describes the breadth of physician networks on the ACA marketplaces in 2017. We find that the overall rate of narrow networks is 21%, which is a decline since 2014 (31%) and 2016 (25%). Narrow networks are concentrated in plans sold on state-based marketplaces, at 42%, compared to 10% of plans on federally-facilitated marketplaces. Issuers that have traditionally offered Medicaid coverage have the highest prevalence of narrow network plans at 36%, with regional/local plans and provider-based plans close behind at 27% and 30%. We also find large differences in narrow networks by state and by plan type.

  6. Microscopic Fermi liquid approach to disordered narrow band systems

    Kolley, E.; Kolley, W.

    1977-01-01

    A Fermi liquid approach to tightly bound electrons in disordered systems is proposed to evaluate two-particle correlation functions L at T=0 deg K. Starting with a random Hubbard model and using a local ladder approximation in the particle-particle channel the irreducible particle-hole vertex is derived, being the kernel of the Bethe-Salpeter equation for L. CPA vertex corrections to the electrical conductivity and, for the ordered case, the correlation-enhanced paramagnetic susceptibility are calculated

  7. Fermi Surfaces in the Antiferromagnetic, Paramagnetic and Polarized Paramagnetic States of CeRh2Si2 Compared with Quantum Oscillation Experiments

    Pourret, Alexandre; Suzuki, Michi-To; Palaccio Morales, Alexandra; Seyfarth, Gabriel; Knebel, Georg; Aoki, Dai; Flouquet, Jacques

    2017-08-01

    The large quantum oscillations observed in the thermoelectric power in the antiferromagnetic (AF) state of the heavy-fermion compound CeRh2Si2 disappear suddenly when entering in the polarized paramagnetic (PPM) state at Hc ˜ 26.5 T, indicating an abrupt reconstruction of the Fermi surface. The electronic band structure was calculated using [LDA+U] for the AF state taking the correct magnetic structure into account, for the PPM state, and for the paramagnetic state (PM). Different Fermi surfaces were obtained for the AF, PM, and PPM states. Due to band folding, a large number of branches was expected and observed in the AF state. The LDA+U calculation was compared with the previous LDA calculations. Furthermore, we compared both calculations with previously published de Haas-van Alphen experiments. The better agreement with the LDA approach suggests that above the critical pressure pc CeRh2Si2 enters in a mixed-valence state. In the PPM state under a high magnetic field, the 4f contribution at the Fermi level EF drops significantly compared with that in the PM state, and the 4f electrons contribute only weakly to the Fermi surface in our approach.

  8. Thermally stimulated luminescence and electron paramagnetic resonance studies on uranium doped calcium phosphate

    Natarajan, V; Veeraraghavan, R; Sastry, M D

    2003-01-01

    Thermally stimulated luminescence (TSL) and electron paramagnetic resonance (EPR) studies on uranium doped calcium phosphate yielded mechanistic information on the observed glow peaks at 365, 410 and 450 K. TSL spectral studies of the glow peaks showed that UO sub 2 sup 2 sup + acts as the luminescent center. Electron paramagnetic resonance studies on gamma-irradiated samples revealed that the predominant radiation induced centers are H sup 0 , PO sub 4 sup 2 sup - , PO sub 3 sup 2 sup - and O sup - ion. Studies on the temperature dependence studies of the EPR spectra of samples annealed to different temperatures indicate the role of H sup 0 and PO sub 4 sup 2 sup - ions in the main glow peak at 410 K.

  9. Nuclear and solid state investigations for the non-cubic paramagnetic system europium in samarium

    Boehm, R.

    1979-01-01

    By means of the time-differential perturbed angular gamma distribution after a nuclear reaction (TDPAD) the g-values of the isomer 1 1/2 - states are measured in 145 Eu and 147 Eu in the host metal Sm. The results are g ( 145 Eu) = + 1.356 + 0.008 g ( 147 Eu) = + 1.28 +- 0.01. The temperature dependence of the paramagnetic correction β obeys a Curie-Weiss law β = 1 + C/CT-, with C = -(50 +- 2) K and THETA = -(29 +- 5) K between 90 K and 1000 K, for both systems, 145 EU Sm and 147 Eu Sm. For room temperature the quadrupole coupling constant νsub(Q) is determined for 145 Eu Sm for the 1 1/2 - state: νsub(Q) = (12.5 +- 0.5) MHz and the paramagnetic relaxation time tausub(p) >= 1 μs. The g values are investigated also theoretically. (BHO)

  10. Electron paramagnetic resonance investigation of polycrystalline CaCu3Ti4O12

    Mozzati, Maria Cristina; Azzoni, Carlo Bruno; Capsoni, Doretta; Bini, Marcella; Massarotti, Vincenzo

    2003-01-01

    Electron paramagnetic resonance (EPR) measurements on pure polycrystalline CaCu 3 Ti 4 O 12 have been performed and are discussed within a crystal-field approach. A symmetric signal centred at g = 2.15 is observed for T>25 K, with no evidence of hyperfine structure. At this temperature an antiferromagnetic transition is observed as confirmed by static magnetization data. Cu defective and 2% doped (V, Cr, Mn, La) samples were also prepared and considered, mainly to understand the nature of the observed paramagnetic centre. Substitutions in the octahedral sites, causing variations of the configuration in CuO 4 -TiO 6 -CuO 4 complexes, change the magnetic and EPR features. To justify the EPR response a strong copper-hole delocalization is suggested

  11. Tunable paramagnetic relaxation enhancements by [Gd(DPA)3]3- for protein structure analysis

    Yagi, Hiromasa; Loscha, Karin V.; Su, Xun-Cheng; Stanton-Cook, Mitchell; Huber, Thomas; Otting, Gottfried

    2010-01-01

    Paramagnetic relaxation enhancements (PRE) present a powerful source of structural information in nuclear magnetic resonance (NMR) studies of proteins and protein-ligand complexes. In contrast to conventional PRE reagents that are covalently attached to the protein, the complex between gadolinium and three dipicolinic acid (DPA) molecules, [Gd(DPA) 3 ] 3- , can bind to proteins in a non-covalent yet site-specific manner. This offers straightforward access to PREs that can be scaled by using different ratios of [Gd(DPA) 3 ] 3- to protein, allowing quantitative distance measurements for nuclear spins within about 15 A of the Gd 3+ ion. Such data accurately define the metal position relative to the protein, greatly enhancing the interpretation of pseudocontact shifts induced by [Ln(DPA) 3 ] 3- complexes of paramagnetic lanthanide (Ln 3+ ) ions other than gadolinium. As an example we studied the quaternary structure of the homodimeric GCN4 leucine zipper.

  12. Correlation between temperature dependence of elastic moduli and Debye temperature of paramagnetic metal

    Bodryakov, V.Yu.; Povzner, A.A.

    2000-01-01

    The correlation between the temperature dependence of elastic moduli and the Debye temperature of paramagnetic metal is analyzed in neglect of the temperature dependence of the Poison coefficient σ within the frames of the Debye-Grueneisen presentations. It is shown, that namely the temperature dependence of the elastic moduli determines primarily the temperature dependence of the Debye temperature Θ(T). On the other hand, the temperature dependence Θ(T) very weakly effects the temperature dependence of the elastic moduli. The later made it possible to formulate the self-consistent approach to calculation of the elastic moduli temperature dependence. The numerical estimates of this dependence parameters are conducted by the example of the all around compression modulus of the paramagnetic lutetium [ru

  13. Temperature dependence of Q-band electron paramagnetic resonance spectra of nitrosyl heme proteins

    Flores, Marco; Wajnberg, Eliane; Bemski, George

    1997-11-01

    The Q-band (35 GHz) electron paramagnetic resonance (EPR) spectra of nitrosyl hemoglobin (Hb N O) and nitrosyl myoglobin (Mb NO) were studied as a function of temperature between 19 K and 200 K. The spectra of both heme proteins show classes of variations as a function of temperature. The first one has previously been associated with the existence of two paramagnetic species, one with rhombic and the other with axial symmetry. The second one manifests itself in changes in the g-factors and linewidths of each species. These changes are correlated with the conformational substates model and associate the variations of g-values with changes in the angle of the N(his)-Fe-N (NO) bond in the rhombic species and with changes in the distance between Fe and N of the proximal (F8) histidine in the axial species. (author) 24 refs., 6 figs.

  14. Study of the ferrimagnetic and paramagnetic phases of magnetite measured by multiple neutron diffraction

    Mazzocchi, V.L.

    1992-01-01

    Structural parameters of the ferrimagnetic and paramagnetic phases of magnetite have been refined from neutron multiple diffraction data. Experimental multiple diffraction patterns used in the refinement, were obtained by measuring the 111 primary reflection of a natural single crystal of this compound, at room temperature for the ferrimagnetic phase and 703 0 C for the paramagnetic phase. Corresponding theoretical patterns for both phases have been calculated by the program MULTI which uses the iterative method for the intensity calculations in neutron multiple diffraction. In this method intensities are calculated as Taylor series expansions summed up to a order sufficient for a good approximation. A step by step process has been used in the refinements according to the parameter-shift method. Both isotropic and anisotropic thermal parameters were used in the calculation of the temperature factor. (author)

  15. Paramagnetic properties of the (U1-xTbx)Co2Ge2 solid solutions

    Kuznietz, Moshe; Pinto, Haim; Ettedgui, Hanania

    1995-01-01

    Polycrystalline (U 1-x Tb x )Co 2 Ge 2 solid solutions have the ThCr 2 Si 2 -type crystal structure and order antiferromagnetically. AC-susceptibility at 80-295 K yields paramagnetic Curie temperatures θ=-350±50, -15±5, -50±15, -12±5, and -80±5 K, and effective magnetic moments μ eff =4.5, 5.9, 7.3, 8.5, and 12.0 (±0.5)μ B , for samples with x=0, 0.25, 0.50, 0.75 and 1, respectively. The high μ eff values are related to occurrence of paramagnetic moments on U, Tb and Co, of which only U and Tb moments order magnetically. ((orig.))

  16. Mg2BIV: Narrow Bandgap Thermoelectric Semiconductors

    Kim, Il-Ho

    2018-05-01

    Thermoelectric materials can convert thermal energy directly into electric energy and vice versa. The electricity generation from waste heat via thermoelectric devices can be considered as a new energy source. For instance, automotive exhaust gas and all industrial processes generate an enormous amount of waste heat that can be converted to electricity by using thermoelectric devices. Magnesium compound Mg2BIV (BIV = Si, Ge or Sn) has a favorable combination of physical and chemical properties and can be a good base for the development of new efficient thermoelectrics. Because they possess similar properties to those of group BIV elemental semiconductors, they have been recognized as good candidates for thermoelectric applications. Mg2Si, Mg2Ge and Mg2Sn with an antifluorite structure are narrow bandgap semiconductors with indirect band gaps of 0.77 eV, 0.74 eV, and 0.35 eV, respectively. Mg2BIV has been recognized as a promising material for thermoelectric energy conversion at temperatures ranging from 500 K to 800 K. Compared to other thermoelectric materials operating in the similar temperature range, such as PbTe and filled skutterudites, the important aspects of Mg2BIV are non-toxic and earth-abundant elements. Based on classical thermoelectric theory, the material factor β ( m* / m e)3/2μκ L -1 can be utilized as the criterion for thermoelectric material selection, where m* is the density-of-states effective mass, me is the mass of an electron, μ is the carrier mobility, and κL is the lattice thermal conductivity. The β for magnesium silicides is 14, which is very high compared to 0.8 for iron silicides, 1.4 for manganese silicides, and 2.6 for silicon-germanium alloys. In this paper, basic phenomena of thermoelectricity and transport parameters for thermoelectric materials were briefly introduced, and thermoelectric properties of Mg2BIV synthesized by using a solid-state reaction were reviewed. In addition, various Mg2BIV compounds were discussed

  17. A sextupole-magnet as variable velocity selector for paramagnetic atomic beams in the thermal range

    Spindler, G.; Ebinghaus, H.; Steffens, E.

    1974-01-01

    The possibility of employing a sextupole-magnet as a velocity selector on account of its velocity dependent focusing properties for paramagnetic atomic beams is investigated. In comparison with a traditional velocity selector with rotating disks, a sextupole-magnet as velocity selector has the advantage of additional focusing and polarizing the atomic beam. Moreover it suppresses polymer molecules without an effective magnetic momentum of the electronic shell

  18. Aberrant paramagnetic signals outside the tumor volume on routine surveillance MRI of brain tumor patients.

    Yust-Katz, Shlomit; Inbar, Edna; Michaeli, Natalia; Limon, Dror; Siegal, Tali

    2017-09-01

    Late complications of cerebral radiation therapy (RT) involve vascular injury with acquired cavernous malformation, telangiectasias and damage to vascular walls which are well recognized in children. Its incidence in adults is unknown. Blood products and iron deposition that accompany vascular injury create paramagnetic effects on MRI. This study retrospectively investigated the frequency of paramagnetic lesions on routine surveillance MRI of adult brain tumor patients. MRI studies of 115 brain tumor patients were reviewed. Only studies containing sequences of either susceptibility weighted images or gradient echo or blood oxygenation level dependent imaging were included. Lesions inside the tumor volume were not considered. 68 studies fulfilled the above criteria and included 48 patients with previous RT (35 followed for >2 years and 13 for 1 year) and 20 patients who were not treated with RT. The median age at time of irradiation was 47 years. Aberrant paramagnetic lesions were found in 23/35 (65%) patients followed for >2 years after RT and in only 1/13 (8%) patients followed for 1-year after radiation (p = 0.03). The 1-year follow-up group did not differ from the control group [2/20 (9%)]. Most lesions were within the radiation field and none of the patients had related symptomatology. The number and incidence of these lesions increased with time and amounted to 75% over 3 years post RT. MRI paramagnetic signal aberrations are common findings in adult brain tumor patients that evolve over time after RT. The clinical significance of these lesions needs further investigation.

  19. First-principles calculation of the magnetic properties of paramagnetic fcc iron

    Johnson, D.D.; Gyorffy, B.L.; Pinski, F.J.; Staunton, J.; Stocks, G.M.

    1985-01-01

    Using the disordered local moment picture of itinerant magnetism, we present calculations of the temperature and volume dependence of the magnetic moment and spin-spin correlations for fcc Fe in the paramagnetic state. These calculations are based on the parameter-free, first principles approach of local spin density functional theory and the coherent potential approximation is used to treat the disorder associated with the random orientation of the local moments

  20. Electron paramagnetic resonance spectrum of fresh fruits processed by gamma-rays

    Jesus, E.F.O. de; Lopes, R.T.

    1999-01-01

    Pulp of irradiated kiwi fruits, after extraction by ethyl alcohol of part of the water and sugars, has been analyzed by electron paramagnetic resonance in order to study the possibility of identifying irradiated fruits. The results allow to confirm that for a period of approximately 12 weeks a triplet with a coupling isotropic constant of 3.05 mT, intensity ratio 1:2:1 and a factor g=2,0026 is visible in irradiated fruits

  1. Evaluation by electronic paramagnetic resonance of the number of free radicals produced in irradiated rat bone

    Marble, G.; Valderas, R.

    1966-01-01

    The number of long half-life free radicals created by gamma irradiation in the bones of the rat has been determined from the electrons paramagnetic resonance spectrum. This number decreases slowly with time (calculated half life: 24 days). It is proportional to the dose of gamma radiation given to the rat. The method could find interesting applications in the field of biological dosimetry. (authors) [fr

  2. Paramagnetic hyperfine interactions of iron in solid ammonia from Moessbauer spectroscopy

    Litterst, F.J.; Saitovitch, E.M.B.; Terra, J.

    1988-01-01

    Moessbauer studies on highly dilute 57 Fe in solid ammonia are reported. The hyperfine parameters of the paramagnetic reaction product FeNH 3 point to a nearly atomic configuration of iron [Ar]3d 7 4s. The electronic spin relaxation slows down rapidly under application of an external magnetic field. The field dependence of the magnetic hyperfine patterns indicates a strong axial magnetic anisotropy. (author) [pt

  3. Ferromagnetic and paramagnetic magnetization of implanted GaN:Ho,Tb,Sm,Tm films

    Maryško, Miroslav; Hejtmánek, Jiří; Laguta, Valentyn; Sofer, Z.; Sedmidubský, D.; Šimek, P.; Veselý, M.; Mikulics, M.; Buchal, C.; Macková, Anna; Malinský, Petr; Wilhelm, R. A.

    2015-01-01

    Roč. 117, č. 17 (2015), "17B907-1"-"17B907-4" ISSN 0021-8979 R&D Projects: GA ČR GA13-20507S; GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:68378271 ; RVO:61389005 Keywords : magnetic field, * ferromagnetic and paramagnetic magnetization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.101, year: 2015

  4. Electron spin resonance study of the demagnetization fields of the ferromagnetic and paramagnetic films

    I.I. Gimazov, Yu.I. Talanov

    2015-12-01

    Full Text Available The results of the electron spin resonance study of the La1-xCaxMnO3 manganite and the diphenyl-picrylhydrazyl thin films for the magnetic field parallel and perpendicular to plane of the films are presented. The temperature dependence of the demagnetizing field is obtained. The parameters of the Curie-Weiss law are estimated for the paramagnetic thin film.

  5. Fano-type coupling of a bound paramagnetic state with 2D continuum

    Rozhansky, I. V.; Averkiev, N. S.; Lähderanta, E.

    2013-01-01

    We analyze an effect of a bound impurity state located at a tunnel distance from a quantum well (QW). The study is focused on the resonance case when the bound state energy lies within the continuum of the QW states. Using the developed theory we calculate spin polarization of 2D holes induced by paramagnetic (Mn) delta-layer in the vicinity of the QW and indirect exchange interaction between two impurities located at a tunnel distance from electron gas

  6. Magnetic resonance tomography of the orbit: First experiences with the paramagnetic contrast medium gadolinium-DTPA

    Markl, A.; Vogl, T.; Scheidhauer, K.; Riedel, K.G.; Oeckler, R.

    1986-01-01

    In 21 patients with orbital mass lesions MRI was performed before and after administration of paramagnetic contrast medium, gadolinium-DPTA. In comparison to the plain scan the differentiation of the tumorous tissue against the surrounding structures was improved after application of contrast medium despite a partially moderate increase in signal intensity. Especially highly vascular tumors and vessel diseases show a significant contrast enhancement. With increasing experience in larger number of patients a tissue differentiation seems to be possible. (orig.) [de

  7. Ghost lines in Moessbauer relaxation spectra

    Price, D.C.

    1985-01-01

    The appearance in Moessbauer relaxation spectra of 'ghost' lines, which are narrow lines that do not correspond to transitions between real hyperfine energy levels of the resonant system, is examined. It is shown that in many cases of interest, the appearance of these 'ghost' lines can be interpreted in terms of the relaxational averaging of one or more of the static interactions of the ion. (orig.)

  8. Observation of a Griffiths-like phase in the paramagnetic regime of ErCo2

    Herrero-Albillos, Julia; GarcIa, Luis Miguel; Bartolome, Fernando

    2009-01-01

    A systematic x-ray magnetic circular dichroism study of the paramagnetic phase of ErCo 2 has recently allowed us to identify the inversion of the net magnetization of the Co net moment with respect to the applied field well above the ferrimagnetic ordering temperature, T c . The study of small-angle neutron scattering measurements has also shown the presence of short range order correlations in the same temperature region. This phenomenon, which we have denoted parimagnetism, may be related to the onset of a Griffiths-like phase in paramagnetic ErCo 2 . We have measured ac susceptibility on ErCo 2 as a function of temperature, applied field and excitation frequency. Several characteristics shared by systems showing a Griffiths phase are present in ErCo 2 , namely the formation of ferromagnetic clusters in the disordered phase, the loss of analyticity of the magnetic susceptibility and its extreme sensitivity to an applied magnetic field. The paramagnetic susceptibility allows us to establish that the magnetic clusters are only formed by Co moments as well as the intrinsic nature of those Co moments.

  9. Topology and immersion depth of an integral membrane protein by paramagnetic rates from dissolved oxygen.

    Al-Abdul-Wahid, M Sameer; Verardi, Raffaello; Veglia, Gianluigi; Prosser, R Scott

    2011-09-01

    In studies of membrane proteins, knowledge of protein topology can provide useful insight into both structure and function. In this work, we present a solution NMR method for the measurement the tilt angle and average immersion depth of alpha helices in membrane proteins, from analysis of the paramagnetic relaxation rate enhancements arising from dissolved oxygen. No modification to the micelle or protein is necessary, and the topology of both transmembrane and amphipathic helices are readily determined. We apply this method to the measure the topology of a monomeric mutant of phospholamban (AFA-PLN), a 52-residue membrane protein containing both an amphipathic and a transmembrane alpha helix. In dodecylphosphocholine micelles, the amphipathic helix of AFA-PLN was found to have a tilt angle of 87° ± 1° and an average immersion depth of 13.2 Å. The transmembrane helix was found to have an average immersion depth of 5.4 Å, indicating residues 41 and 42 are closest to the micelle centre. The resolution of paramagnetic relaxation rate enhancements from dissolved oxygen compares favourably to those from Ni (II), a hydrophilic paramagnetic species.

  10. Topology and immersion depth of an integral membrane protein by paramagnetic rates from dissolved oxygen

    Al-Abdul-Wahid, M. Sameer; Verardi, Raffaello; Veglia, Gianluigi; Prosser, R. Scott

    2011-01-01

    In studies of membrane proteins, knowledge of protein topology can provide useful insight into both structure and function. In this work, we present a solution NMR method for the measurement the tilt angle and average immersion depth of alpha helices in membrane proteins, from analysis of the paramagnetic relaxation rate enhancements arising from dissolved oxygen. No modification to the micelle or protein is necessary, and the topology of both transmembrane and amphipathic helices are readily determined. We apply this method to the measure the topology of a monomeric mutant of phospholamban (AFA-PLN), a 52-residue membrane protein containing both an amphipathic and a transmembrane alpha helix. In dodecylphosphocholine micelles, the amphipathic helix of AFA-PLN was found to have a tilt angle of 87° ± 1° and an average immersion depth of 13.2 Å. The transmembrane helix was found to have an average immersion depth of 5.4 Å, indicating residues 41 and 42 are closest to the micelle centre. The resolution of paramagnetic relaxation rate enhancements from dissolved oxygen compares favourably to those from Ni (II), a hydrophilic paramagnetic species.

  11. Towards interpretation of intermolecular paramagnetic relaxation enhancement outside the fast exchange limit.

    Ceccon, Alberto; Marius Clore, G; Tugarinov, Vitali

    2016-09-01

    In an exchanging system between major and minor species, the transverse paramagnetic relaxation enhancement rate observed on the resonances of the major species (Γ 2 (app) ) is dependent upon the exchange regime between the species. Quantitative analysis of PRE data in such systems typically assumes that the overall exchange rate k ex between the species is fast on the PRE time scale (k ex ≫ Γ2). Recently, we have characterized the kinetics of binding of the model protein ubiquitin to large (LUV) and small (SUV) unilamellar lipid-based nanoparticles or liposomes (Ceccon A, Tugarinov V, Bax A, Clore GM (2016). J Am Chem Soc 138:5789-5792). Building upon these results and taking advantage of a strong paramagnetic agent with an isotropic g-tensor, Gd(3+), we were able to measure intermolecular methyl carbon and proton PREs between paramagnetically-tagged liposomes and ubiquitin. In the limit of fast exchange (k ex ≫ Γ2) the ratio of the apparent proton to carbon methyl PREs, ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ), is equal to the square of the ratio of the gyromagnetic ratios of the two nuclei, (γΗ/γC)(2). However, outside the fast exchange regime, under intermediate exchange conditions (e.g. when Γ2 is comparable in magnitude to k ex) the ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ) ratio provides a reliable measure of the 'true' methyl PREs.

  12. Upcycling: converting waste plastics into paramagnetic, conducting, solid, pure carbon microspheres.

    Pol, Vilas Ganpat

    2010-06-15

    The recent tremendous increase in the volume of waste plastics (WP) will have a harmful environmental impact on the health of living beings. Hundreds of years are required to degrade WP in atmospheric conditions. Hence, in coming years, in addition to traditional recycling services, innovative "upcycling" processes are necessary. This article presents an environmentally benign, solvent-free autogenic process that converts various WP [low density polyethylene (LDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), polystyrene (PS), or their mixtures] into carbon microspheres (CMSs), an industrially significant, value-added product. The thermal dissociation of these individual or mixed WP in a closed reactor under autogenic pressure ( approximately 1000 psi) produced dry, pure powder of CMSs. In this paper, the optimization of process parameters such as the effect of mixing of WP with other materials, and the role of reaction temperature and time are reported. Employing advanced analytical techniques, the atomic structure, composition, and morphology of as-obtained CMSs were analyzed. The room-temperature paramagnetism in CMSs prepared from waste LDPE, HDPE, and PS was further studied by electron paramagnetic resonance (EPR). The conducting and paramagnetic nature of CMSs holds promise for their potential applications in toners, printers, paints, batteries, lubricants, and tires.

  13. Comparative study between different nitrosyls hemoproteins using electron paramagnetic resonance; Estudo comparativo entre diferentes nitrosil hemoproteinas por ressonancia paramagnetica eletronica

    Caracelli, Ignez

    1988-12-31

    Using the Electron Paramagnetic Resonance (EPR) technique, the properties of several nitrosyl hemoproteins were investigated as a function of temperature, pH and nitric oxide (NO) concentration. (author). 59 refs., 53 figs., 6 tabs.

  14. Q2 anti Q2 states with relatively narrow widths

    Ono, Seiji.

    1978-09-01

    Using the mass formulas which correctly predict the mass of mesons and baryons the mass of diquark states is computed. From this mass spectrum the existance of the observed narrow baryonia and wide baryonia can be naturally understood. Other relatively narrow Q 2 anti Q 2 states are predicted to exist. (orig.) [de

  15. Bayesian Face Recognition and Perceptual Narrowing in Face-Space

    Balas, Benjamin

    2012-01-01

    During the first year of life, infants' face recognition abilities are subject to "perceptual narrowing", the end result of which is that observers lose the ability to distinguish previously discriminable faces (e.g. other-race faces) from one another. Perceptual narrowing has been reported for faces of different species and different races, in…

  16. Two-dimensional NMR measurement and point dipole model prediction of paramagnetic shift tensors in solids

    Walder, Brennan J.; Davis, Michael C.; Grandinetti, Philip J. [Department of Chemistry, Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210 (United States); Dey, Krishna K. [Department of Physics, Dr. H. S. Gour University, Sagar, Madhya Pradesh 470003 (India); Baltisberger, Jay H. [Division of Natural Science, Mathematics, and Nursing, Berea College, Berea, Kentucky 40403 (United States)

    2015-01-07

    A new two-dimensional Nuclear Magnetic Resonance (NMR) experiment to separate and correlate the first-order quadrupolar and chemical/paramagnetic shift interactions is described. This experiment, which we call the shifting-d echo experiment, allows a more precise determination of tensor principal components values and their relative orientation. It is designed using the recently introduced symmetry pathway concept. A comparison of the shifting-d experiment with earlier proposed methods is presented and experimentally illustrated in the case of {sup 2}H (I = 1) paramagnetic shift and quadrupolar tensors of CuCl{sub 2}⋅2D{sub 2}O. The benefits of the shifting-d echo experiment over other methods are a factor of two improvement in sensitivity and the suppression of major artifacts. From the 2D lineshape analysis of the shifting-d spectrum, the {sup 2}H quadrupolar coupling parameters are 〈C{sub q}〉 = 118.1 kHz and 〈η{sub q}〉 = 0.88, and the {sup 2}H paramagnetic shift tensor anisotropy parameters are 〈ζ{sub P}〉 = − 152.5 ppm and 〈η{sub P}〉 = 0.91. The orientation of the quadrupolar coupling principal axis system (PAS) relative to the paramagnetic shift anisotropy principal axis system is given by (α,β,γ)=((π)/2 ,(π)/2 ,0). Using a simple ligand hopping model, the tensor parameters in the absence of exchange are estimated. On the basis of this analysis, the instantaneous principal components and orientation of the quadrupolar coupling are found to be in excellent agreement with previous measurements. A new point dipole model for predicting the paramagnetic shift tensor is proposed yielding significantly better agreement than previously used models. In the new model, the dipoles are displaced from nuclei at positions associated with high electron density in the singly occupied molecular orbital predicted from ligand field theory.

  17. Stable and rigid DTPA-like paramagnetic tags suitable for in vitro and in situ protein NMR analysis.

    Chen, Jia-Liang; Zhao, Yu; Gong, Yan-Jun; Pan, Bin-Bin; Wang, Xiao; Su, Xun-Cheng

    2018-02-01

    Organic synthesis of a ligand with high binding affinities for paramagnetic lanthanide ions is an effective way of generating paramagnetic effects on proteins. These paramagnetic effects manifested in high-resolution NMR spectroscopy are valuable dynamic and structural restraints of proteins and protein-ligand complexes. A paramagnetic tag generally contains a metal chelating moiety and a reactive group for protein modification. Herein we report two new DTPA-like tags, 4PS-PyDTTA and 4PS-6M-PyDTTA that can be site-specifically attached to a protein with a stable thioether bond. Both protein-tag adducts form stable lanthanide complexes, of which the binding affinities and paramagnetic tensors are tunable with respect to the 6-methyl group in pyridine. Paramagnetic relaxation enhancement (PRE) effects of Gd(III) complex on protein-tag adducts were evaluated in comparison with pseudocontact shift (PCS), and the results indicated that both 4PS-PyDTTA and 4PS-6M-PyDTTA tags are rigid and present high-quality PREs that are crucially important in elucidation of the dynamics and interactions of proteins and protein-ligand complexes. We also show that these two tags are suitable for in-situ protein NMR analysis.

  18. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis

    Yang, Yin; Huang, Feng [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China); Huber, Thomas [Australian National University, Research School of Chemistry (Australia); Su, Xun-Cheng, E-mail: xunchengsu@nankai.edu.cn [Nankai University, State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) (China)

    2016-02-15

    Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i − 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.

  19. Paramagnetic moments in YBa{sub 2}Cu{sub 3}O{sub 7−δ} nanocomposite films

    Dias, F.T.; Vieira, V.N.; Silva, D.L. [Instituto de Física e Matemática, Universidade Federal de Pelotas, C.P. 354, 96010-900 Pelotas, RS (Brazil); Albino Aguiar, J. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Valadão, D.R.B., E-mail: danielavaladao.ufpe@gmail.com [Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Obradors, X.; Puig, T. [Institut de Ciència de Materials de Barcelona, ICMAB-CSIC, Campus U.A. Barcelona, 08193 Bellaterra (Spain); Wolff-Fabris, F.; Kampert, E. [Dresden High Magnetic Field Laboratory, HZ Dresden-Rossendorf , 01314 Dresden (Germany)

    2014-08-15

    Highlights: • The paramagnetic Meissner effect was observed in a nanocomposite YBaCuO thin film. • The paramagnetic moments in FC experiments were observed up to 10 T. • The paramagnetic Meissner effect increases when the magnetic field is increased. • Results may be explained based on the flux compression scenario and vortex pinning. • An apparent saturation tendency of the paramagnetic moments could be observed. - Abstract: We report on magnetization studies in YBa{sub 2}Cu{sub 3}O{sub 7−δ} thin films with dispersed Ba{sub 2}YTaO{sub 6} nanoparticles. The magnetization measurements were made using a superconducting quantum interference device (SQUID) and a vibrating sample magnetometer (VSM). Magnetic moments were measured as functions temperature using zero-field cooling (ZFC) and field-cooled (FC) prescriptions for magnetic fields up to 10 T applied parallel and perpendicular to the ab planes. A paramagnetic response related to the superconducting state was observed during the FC experiments. This effect, known as paramagnetic Meissner effect (PME), apparently increases when the magnetic field is increased. We discuss our PME results in terms of the strong pinning scenario modulated by Ba{sub 2}YTaO{sub 6} nanoparticles dispersed into the superconducting matrix.

  20. Reactive oxygen species' role in endothelial dysfunction by electron paramagnetic resonance

    Wassall, Cynthia D.

    The endothelium is a single layer of cells lining the arteries and is involved in many physiological reactions which are responsible for vascular tone. Free radicals are important participants in these chemical reactions in the endothelium. Here we quantify free radicals, ex vivo, in biological tissue with continuous wave electron paramagnetic resonance (EPR). In all of the experiments in this thesis, we use a novel EPR spin trapping technique that has been developed for tissue segments. EPR spin trapping is often considered the 'gold standard' in reactive oxygen species (ROS) detection because of its sensitivity and non-invasive nature. In all experiments, tissue was placed in physiological saline solution with 190-mM PBN (N-tert -butyl-α-phenylnitrone), 10% by volume dimethyl-sulphoxide (DMSO) for cryopreservation, and incubated in the dark for between 30 minutes up to 2 hours at 37°C while gently being stirred. Tissue and supernatant were then loaded into a syringe and frozen at -80°C until EPR analysis. In our experiments, the EPR spectra were normalized with respect to tissue volume. Conducting experiments at liquid nitrogen temperature leads to some experimental advantages. The freezing of the spin adducts renders them stable over a longer period, which allows ample time to analyze tissue samples for ROS. The dielectric constant of ice is greatly reduced over its liquid counterpart; this property of water enables larger sample volumes to be inserted into the EPR cavity without overloading it and leads to enhanced signal detection. Due to Maxwell-Boltzmann statistics, the population difference goes up as the temperature goes down, so this phenomenon enhances the signal intensity as well. With the 'gold standard' assertion in mind, we investigated whether slicing tissue to assay ROS that is commonly used in fluorescence experiments will show more free radical generation than tissue of a similar volume that remains unsliced. Sliced tissue exhibited a 76

  1. Narrow-band imaging of the inner R Aquarii nebula - Further evidence for shock excitation

    Burgarella, D.; Paresce, F.

    1991-01-01

    The jetlike nebulosity in the inner regions of the symbiotic variable R Aqr was imaged through narrow-band interference filters. A high spatial resolution image in the forbidden N II 6583 A line shows that the relative fluxes of features B and D defined by Paresce et al. (1988) have changed in the sense of a higher D/B brightness ratio at this line in a little over a year with respect to that observed previously in similar seeing conditions. The overall morphology of the jet has remained stable in this period. Line ratios for feature B are presented which can be best understood in terms of excitation of gas clumps surrounding R Aqr by a moving shock. Comparison of the observed fluxes with theoretical expectations yields shock velocity of order 90-100 km/s, a preshock gas density of roughly 10/cu cm, and a gas temperature of roughly 10,000 K. 26 refs

  2. Are narrow mesons, baryons and dibaryons evidence for multiquark states?

    Tatischeff, B.; Yonnet, J.

    2000-01-01

    Several narrow structures have been progressively observed since the last fifteen years, in di-baryonic invariant mass spectra or in missing mass spectra. More recently, narrow structures were observed in baryonic and now in mesonic mass spectra. Since these small peaks appear at fixed masses, independently of the experiment, they are associated with real states. There is no room to explain these states within classical nuclear physics taking into account baryonic and mesonic degrees of freedom. An interpretation is proposed, which associate these narrow structures with two coloured quark clusters. (authors)

  3. Towards interpretation of intermolecular paramagnetic relaxation enhancement outside the fast exchange limit

    Ceccon, Alberto; Marius Clore, G., E-mail: mariusc@mail.nih.gov; Tugarinov, Vitali, E-mail: vitali.tugarinov@nih.gov [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)

    2016-09-15

    In an exchanging system between major and minor species, the transverse paramagnetic relaxation enhancement rate observed on the resonances of the major species (Γ{sub 2}{sup app}) is dependent upon the exchange regime between the species. Quantitative analysis of PRE data in such systems typically assumes that the overall exchange rate k{sub ex} between the species is fast on the PRE time scale (k{sub ex} ≫ Γ{sub 2}). Recently, we have characterized the kinetics of binding of the model protein ubiquitin to large (LUV) and small (SUV) unilamellar lipid-based nanoparticles or liposomes (Ceccon A, Tugarinov V, Bax A, Clore GM (2016). J Am Chem Soc 138:5789–5792). Building upon these results and taking advantage of a strong paramagnetic agent with an isotropic g-tensor, Gd{sup 3+}, we were able to measure intermolecular methyl carbon and proton PREs between paramagnetically-tagged liposomes and ubiquitin. In the limit of fast exchange (k{sub ex} ≫ Γ{sub 2}) the ratio of the apparent proton to carbon methyl PREs, ({sup 1}H{sub m}–Γ{sub 2}{sup app})/({sup 13}C{sub m}–Γ{sub 2}{sup app}), is equal to the square of the ratio of the gyromagnetic ratios of the two nuclei, (γ{sub Η}/γ{sub C}){sup 2}. However, outside the fast exchange regime, under intermediate exchange conditions (e.g. when Γ{sub 2} is comparable in magnitude to k{sub ex}) the ({sup 1}H{sub m}–Γ{sub 2}{sup app})/({sup 13}C{sub m}–Γ{sub 2}{sup app}) ratio provides a reliable measure of the ‘true’ methyl PREs.

  4. Curie-type paramagnetic NMR relaxation in the aqueous solution of Ni(II).

    Mareš, Jiří; Hanni, Matti; Lantto, Perttu; Lounila, Juhani; Vaara, Juha

    2014-04-21

    Ni(2+)(aq) has been used for many decades as a model system for paramagnetic nuclear magnetic resonance (pNMR) relaxation studies. More recently, its magnetic properties and also nuclear magnetic relaxation rates have been studied computationally. We have calculated electron paramagnetic resonance and NMR parameters using quantum-mechanical (QM) computation of molecular dynamics snapshots, obtained using a polarizable empirical force field. Statistical averages of hyperfine coupling, g- and zero-field splitting tensors, as well as the pNMR shielding terms, are compared to the available experimental and computational data. In accordance with our previous work, the isotropic hyperfine coupling as well as nuclear shielding values agree well with experimental measurements for the (17)O nuclei of water molecules in the first solvation shell of the nickel ion, whereas larger deviations are found for (1)H centers. We report, for the first time, the Curie-type contribution to the pNMR relaxation rate using QM calculations together with Redfield relaxation theory. The Curie relaxation mechanism is analogous to chemical shift anisotropy relaxation, well-known in diamagnetic NMR. Due to the predominance of other types of paramagnetic relaxation mechanisms for this system, it is possible to extract the Curie term only computationally. The Curie mechanism alone would result in around 16 and 20 s(-1) of relaxation rates (R1 and R2 respectively) for the (1)H nuclei of water molecules bonded to the Ni(2+) center, in a magnetic field of 11.7 T. The corresponding (17)O relaxation rates are around 33 and 38 s(-1). We also report the Curie contribution to the relaxation rate for molecules beyond the first solvation shell in a 1 M solution of Ni(2+) in water.

  5. Towards interpretation of intermolecular paramagnetic relaxation enhancement outside the fast exchange limit

    Ceccon, Alberto; Marius Clore, G.; Tugarinov, Vitali

    2016-01-01

    In an exchanging system between major and minor species, the transverse paramagnetic relaxation enhancement rate observed on the resonances of the major species (Γ_2"a"p"p) is dependent upon the exchange regime between the species. Quantitative analysis of PRE data in such systems typically assumes that the overall exchange rate k_e_x between the species is fast on the PRE time scale (k_e_x ≫ Γ_2). Recently, we have characterized the kinetics of binding of the model protein ubiquitin to large (LUV) and small (SUV) unilamellar lipid-based nanoparticles or liposomes (Ceccon A, Tugarinov V, Bax A, Clore GM (2016). J Am Chem Soc 138:5789–5792). Building upon these results and taking advantage of a strong paramagnetic agent with an isotropic g-tensor, Gd"3"+, we were able to measure intermolecular methyl carbon and proton PREs between paramagnetically-tagged liposomes and ubiquitin. In the limit of fast exchange (k_e_x ≫ Γ_2) the ratio of the apparent proton to carbon methyl PREs, ("1H_m–Γ_2"a"p"p)/("1"3C_m–Γ_2"a"p"p), is equal to the square of the ratio of the gyromagnetic ratios of the two nuclei, (γ_Η/γ_C)"2. However, outside the fast exchange regime, under intermediate exchange conditions (e.g. when Γ_2 is comparable in magnitude to k_e_x) the ("1H_m–Γ_2"a"p"p)/("1"3C_m–Γ_2"a"p"p) ratio provides a reliable measure of the ‘true’ methyl PREs.

  6. What's in a name? Expiratory tracheal narrowing in adults explained

    Leong, P.; Bardin, P.G.; Lau, K.K.

    2013-01-01

    Tracheomalacia, tracheobronchomalacia, and excessive dynamic airway collapse are all terms used to describe tracheal narrowing in expiration. The first two describe luminal reduction from cartilage softening and the latter refers to luminal reduction from exaggerated posterior membrane movement. Expiratory tracheal narrowing is a frequent occurrence that can cause symptoms of airway obstruction, such as dyspnoea, wheeze, and exercise intolerance. The accurate diagnosis and quantification of expiratory tracheal narrowing has important aetiological, therapeutic, and prognostic implications. The reference standard for diagnosis has traditionally been bronchoscopy; however, this method has significant limitations. Expiratory tracheal disorders are readily detected by four-dimensional dynamic volume multidetector computed tomography (4D-CT), an emerging, non-invasive method that will potentially enable detection and quantification of these conditions. This review discusses the morphological forms of expiratory tracheal narrowing and demonstrates the utility of 4D-CT in the diagnosis, quantification, and treatment of these important conditions

  7. Single frequency narrow linewidth 2 micron laser, Phase I

    National Aeronautics and Space Administration — NASA needs narrow linewidth lasers in the 1.5 or 2 micron wavelength regime for coherent Lidar applications. The laser should be tunable by several nm and frequency...

  8. Subglottic cysts and asymmetrical subglottic narrowing on neck radiograph

    Holinger, L.D.; Torium, D.M.; Anandappa, E.C.

    1988-01-01

    The congenital subglottic hemangioma typically appears as an asymmetric subglottic narrowing or mass on frontal neck radiograph. Therefore, soft tissue neck radiography has been advocated as a definitive non-operative approach for diagnosing these lesions. However, we have noted similar asymmetric subglottic narrowing in patients with acquired subglottic cysts. These retention cysts occur following long-term intubation in the neonate. The mechanism probably involves subglottic fibrosis which obstructs glands with subsequent cyst formation. Acquired subglottic cysts typically appear as an asymmetric narrowing on frontal or lateral soft tissue neck radiographs. These lesions may produce airway compromise but are effectively treated by forceps or laser removal. Acquired subglottic cysts must be included in the differential diagnosis of asymmetric subglottic narrowing. The definitive diagnosis is made by direct laryngoscopy, not soft tissue neck radiograph. (orig.)

  9. THE TREATMENT OF OPEN- AND NARROW-ANGLE GLAUCOMA

    1971-04-10

    Apr 10, 1971 ... glaucoma will be considered: narrow-angle glaucoma. (acute glaucoma) and ... emotional or a physical crisis. The pain is in the distribu- .... ness, not increased pressure, haunts people suffering from glaucoma'.' The saga of ...

  10. Comment on the narrow structure reported by Amaryan et al

    Anghinolfi, M.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Bellis, M.; Biselli, A. S.; Bookwalter, C.; Boiarinov, S.; Bosted, P.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Cole, P. L.

    2012-01-01

    The CLAS Collaboration provides a comment on the physics interpretation of the results presented in a paper published by M. Amaryan et al. regarding the possible observation of a narrow structure in the mass spectrum of a photoproduction experiment.

  11. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    Sohail, Muhammad Sadiq; Al-Naffouri, Tareq Y.; Al-Ghadhban, Samir N.

    2012-01-01

    This paper presents a maximum likelihood (ML) approach to mitigate the effect of narrow band interference (NBI) in a zero padded orthogonal frequency division multiplexing (ZP-OFDM) system. The NBI is assumed to be time variant and asynchronous

  12. Molecular packing and magnetic properties of lithium naphthalocyanine crystals: hollow channels enabling permeability and paramagnetic sensitivity to molecular oxygen

    Pandian, Ramasamy P.; Dolgos, Michelle; Marginean, Camelia; Woodward, Patrick M.; Hammel, P. Chris; Manoharan, Periakaruppan T.; Kuppusamy, Periannan

    2009-01-01

    The synthesis, structural framework, magnetic and oxygen-sensing properties of a lithium naphthalocyanine (LiNc) radical probe are presented. LiNc was synthesized in the form of a microcrystalline powder using a chemical method and characterized by electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, powder X-ray diffraction analysis, and mass spectrometry. X-Ray powder diffraction studies revealed a structural framework that possesses long, hollow channels running parallel to the packing direction. The channels measured approximately 5.0 × 5.4 Å2 in the two-dimensional plane perpendicular to the length of the channel, enabling diffusion of oxygen molecules (2.9 × 3.9 Å2) through the channel. The powdered LiNc exhibited a single, sharp EPR line under anoxic conditions, with a peak-to-peak linewidth of 630 mG at room temperature. The linewidth was sensitive to surrounding molecular oxygen, showing a linear increase in pO2 with an oxygen sensitivity of 31.2 mG per mmHg. The LiNc microcrystals can be further prepared as nano-sized crystals without the loss of its high oxygen-sensing properties. The thermal variation of the magnetic properties of LiNc, such as the EPR linewidth, EPR intensity and magnetic susceptibility revealed the existence of two different temperature regimes of magnetic coupling and hence differing columnar packing, both being one-dimensional antiferromagnetic chains but with differing magnitudes of exchange coupling constants. At a temperature of ∼50 K, LiNc crystals undergo a reversible phase transition. The high degree of oxygen-sensitivity of micro- and nano-sized crystals of LiNc, combined with excellent stability, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy. PMID:19809598

  13. Increasing the sensitivity of NMR diffusion measurements by paramagnetic longitudinal relaxation enhancement, with application to ribosome–nascent chain complexes

    Chan, Sammy H. S.; Waudby, Christopher A.; Cassaignau, Anaïs M. E.; Cabrita, Lisa D.; Christodoulou, John

    2015-01-01

    The translational diffusion of macromolecules can be examined non-invasively by stimulated echo (STE) NMR experiments to accurately determine their molecular sizes. These measurements can be important probes of intermolecular interactions and protein folding and unfolding, and are crucial in monitoring the integrity of large macromolecular assemblies such as ribosome–nascent chain complexes (RNCs). However, NMR studies of these complexes can be severely constrained by their slow tumbling, low solubility (with maximum concentrations of up to 10 μM), and short lifetimes resulting in weak signal, and therefore continuing improvements in experimental sensitivity are essential. Here we explore the use of the paramagnetic longitudinal relaxation enhancement (PLRE) agent NiDO2A on the sensitivity of 15 N XSTE and SORDID heteronuclear STE experiments, which can be used to monitor the integrity of these unstable complexes. We exploit the dependence of the PLRE effect on the gyromagnetic ratio and electronic relaxation time to accelerate recovery of 1 H magnetization without adversely affecting storage on N z during diffusion delays or introducing significant transverse relaxation line broadening. By applying the longitudinal relaxation-optimized SORDID pulse sequence together with NiDO2A to 70S Escherichia coli ribosomes and RNCs, NMR diffusion sensitivity enhancements of up to 4.5-fold relative to XSTE are achieved, alongside ∼1.9-fold improvements in two-dimensional NMR sensitivity, without compromising the sample integrity. We anticipate these results will significantly advance the use of NMR to probe dynamic regions of ribosomes and other large, unstable macromolecular assemblies.Graphical Abstract

  14. Electron paramagnetic resonance and optical absorption study of V{sup 4+} centres in YVO{sub 4} crystals

    Garces, N Y [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States); Stevens, K T [Northrop Grumman Space Technology, Synoptics, Charlotte, NC 28273 (United States); Foundos, G K [Northrop Grumman Space Technology, Synoptics, Charlotte, NC 28273 (United States); Halliburton, L E [Department of Physics, West Virginia University, Morgantown, WV 26506 (United States)

    2004-10-06

    Electron paramagnetic resonance (EPR) has been used to characterize three distinct V{sup 4+} centres in undoped Czochralski-grown yttrium orthovanadate (YVO{sub 4}) crystals. These EPR signals are observed at low temperatures, and their average c-axis splittings between adjacent {sup 51}V hyperfine lines are 40 G, 123 G, and 140 G. We refer to these centres as [V{sup 4+}]{sub A}, [V{sup 4+}]{sub B}, and [V{sup 4+}]{sub C}, respectively. The [V{sup 4+}]{sub A} and [V{sup 4+}]{sub B} centres are present in as-grown crystals. Exposure at 77 K to ionizing radiation (x-rays or an ultraviolet laser beam) destroys these centres and creates the [V{sup 4+}]{sub C} centres. The as-grown state of the crystal is restored upon returning to room temperature. Angular dependence data are used to determine the principal values and principal directions of the g tensor and the {sup 51}V hyperfine tensor for each of the centres. We suggest that the [V{sup 4+}]{sub A} centre is a V{sup 4+} ion adjacent to an oxygen vacancy and that the [V{sup 4+}]{sub B} centre is a V{sup 4+} ion substituting for a Y{sup 3+} ion (i.e. a vanadium antisite defect). The [V{sup 4+}]{sub C} centre is assigned to a V{sup 4+} ion at a regular vanadium site with a nearby stabilizing defect, possibly a Zr{sup 4+} on a Y{sup 3+} site. In as-grown crystals, there is a correlation between the number of [V{sup 4+}]{sub A} centres and the intensity (at 380 nm) of a broad near-edge optical absorption band. This band, now associated with oxygen vacancies, gives YVO{sub 4} a 'yellow' appearance.

  15. A Search for Blazar-Like Radio-Loud Narrow-Line Seyfert 1 Galaxies

    Hugh R. Miller

    2017-03-01

    Full Text Available We report the results of an observational program to investigate the gamma-ray and optical variability properties of the vRL NLSY1 galaxies listed in the Yuan et al. sample. We have identified 17 members of the Yuan et al. sample possibly associated with gamma-ray sources based on a combination of their optical polarization and optical variability and their gamma-ray properties. Eight have previously been associated with gamma-ray sources. We find nine additional members that we predict are excellent candidates to be associated with gamma-ray sources in the future. All 17 sources have many properties in common with flat spectrum radio quasars (FSRQs, suggesting that they may, in fact, constitute a new subclass of FSRQs.

  16. INDEPENDENT EVALUATION OF THE GAM EX5ALN MINIATURE LINE-NARROWED KRF EXCIMER LASER

    2017-06-01

    reliant on digital communication, perhaps a simple downloadable video ( YouTube ) could be prepared to facilitate the installation procedures. At a...prolonged use influenced the laser output. The stability of the laser under conditions of high discharge voltages and rapid firing rates was examined

  17. Tunable, Narrow Line Width Mid-Infrared Laser Source, Phase II

    National Aeronautics and Space Administration — The purpose of this project is to advance the technology of interband cascade (IC) lasers and their facet coatings and to design, build, and deliver to NASA a...

  18. Tunable, Narrow Line Width Mid-Infrared Laser Source, Phase I

    National Aeronautics and Space Administration — Maxion Technologies, Inc. (Maxion) and Professor Mario Dagenais and his group at the University of Maryland (UMD) jointly propose to develop a compact, efficient,...

  19. Narrow Framing and Long-Term Care Insurance

    Daniel Gottlieb; Olivia S. Mitchell

    2015-01-01

    We propose a model of narrow framing in insurance and test it using data from a new module we designed and fielded in the Health and Retirement Study. We show that respondents subject to narrow framing are substantially less likely to buy long-term care insurance than average. This effect is distinct from, and much larger than, the effects of risk aversion or adverse selection, and it offers a new explanation for why people underinsure their later-life care needs.

  20. Application of hot neutron scattering to the problem of 3d metallic paramagnetism

    Brown, P.J.; Capellmann, H.; Deportes, J.; Givord, D.; Johnson, S.M.; Ziebeck, K.R.A.

    1984-01-01

    The authors report in this paper on experiments performed in Fe and Ni in their paramagnetic state. Scattering of polarized neutrons with polarization analysis has been used to separate out the magnetic scattering from other sources of scattering. Large quasi-elastic scattering is observed which characterizes ferromagnetic correlations over several inter-atomic distances. The large-Q component of the scattering is fairly small as expected for itinerant electrons in which the energy of magnetic excitations may be of the order of the bandwidth. These should help discriminate between the itinerant and localized models

  1. Investigation of the paramagnetic phase of bcc iron using polarized neutron scattering

    Wicksted, J.P.; Shirane, G.; Steinsvoll, O.

    1983-01-01

    Recent neutron scattering experiments on Ni and Fe (4%-Si) above T/sub c/ have demonstrated that a simple paramagnetic scattering function S(Qω) proportional to 1/(kappa 1 2 + q 2 ).GAMMA/(GAMMA 2 + ω 2 ) can explain the persistent spin wave ridges previously reported by Lynn and Mook. We present our new polarized beam results on pure Fe and describe in some detail the special problems associated with the unpolarized beam studies of magnetic cross sections at high temperatures

  2. Detection of helium-containing paramagnetic complex at decay of tritium incorporated in HTO and DTO

    Legasov, V.A.; Usatyj, A.F.; Ibragimov, R.A.; Myasoedov, N.F.

    1979-01-01

    EPR technique was used to study the paramagnetic centers appearing during long-term storage of frozen (77 K) non-deoxygenated light (H 2 O) and heavy (D 2 O) water containing 3.5% vol. highly active HTO (29 ci/cm 3 ), so that the resulting activity of the sample (0.1 ml) was about 100 mci. For comparison, the same samples containing no HTO but irradiated by Co-60 rays were studied under identical conditions. A schematic of the processes involved in tritium decay in DTO (or HTO) in the aqueous matrix frozen at low temperatures was suggested

  3. Transforming from paramagnetism to room temperature ferromagnetism in CuO by ball milling

    Daqiang Gao

    2011-12-01

    Full Text Available In this work, we experimentally demonstrate that it is possible to induce ferromagnetism in CuO by ball milling without any ferromagnetic dopant. The magnetic measurements indicate that paramagnetic CuO is driven to the ferromagnetic state at room temperature by ball milling gradually. The saturation magnetization of the milled powders is found to increase with expanding the milling time and then decrease by annealing under atmosphere. The fitted X-ray photoelectron spectroscopy results indicate that the observed induction and weaken of the ferromagnetism shows close relationship with the valence charged oxygen vacancies (Cu1+-VO in CuO.

  4. Detection and characterisation of radicals using electron paramagnetic resonance (EPR) spin trapping and related methods

    Davies, Michael Jonathan

    2016-01-01

    Electron paramagnetic resonance (EPR) spectroscopy (also known as electron spin resonance, ESR, or electron magnetic resonance, EMR, spectroscopy) is often described as the “gold standard” for the detection and characterisation of radicals in chemical, biological and medical systems. The article...... reviews aspects of EPR spectroscopy and discusses how this methodology and related techniques can be used to obtain useful information from biological systems. Consideration is given to the direct detection of radicals, the use of spin traps and the detection of nitric oxide, and the advantages...

  5. Al-doped MgB_2 materials studied using electron paramagnetic resonance and Raman spectroscopy

    Bateni, Ali; Somer, Mehmet; Erdem, Emre; Repp, Sergej; Weber, Stefan

    2016-01-01

    Undoped and aluminum (Al) doped magnesium diboride (MgB_2) samples were synthesized using a high-temperature solid-state synthesis method. The microscopic defect structures of Al-doped MgB_2 samples were systematically investigated using X-ray powder diffraction, Raman spectroscopy, and electron paramagnetic resonance. It was found that Mg-vacancies are responsible for defect-induced peculiarities in MgB_2. Above a certain level of Al doping, enhanced conductive properties of MgB_2 disappear due to filling of vacancies or trapping of Al in Mg-related vacancy sites.

  6. Er3+ impurities in KTiOPO4 studied by electron paramagnetic resonance

    Bravo, D; MartIn, A; Carvajal, J J; Aguilo, M; DIaz, F; Lopez, F J

    2006-01-01

    An electron paramagnetic resonance (EPR) study of Er 3+ ions in single crystals of KTiOPO 4 (KTP) is presented. The EPR spectra show the existence of eight different Er 3+ centres. The g-matrix has been determined for all eight centres from the analysis of the angular dependences of the spectrum in three planes of the crystal. This study provides strong evidence about incorporation of erbium in the low-symmetry K + sites of KTP. Possible reasons for the appearance of such a large number of Er 3+ centres are discussed

  7. Low-temperature specific heat of YMn sub 2 in the paramagnetic and antiferromagnetic phases

    Fisher, R.A.; Emerson, J.P.; Phillips, N.E. (Lawrence Berkeley Lab., CA (United States)); Ballou, R.; Lelievre-Berna, E. (Centre National de la Recherche Scientifique (CNRS), 38 - Grenoble (France). Lab. Louis Neel)

    1992-07-01

    The low-temperature specific heat of YMn{sub 2} has been measured at applied pressures of 0 to 7.7 kbar. A paramagnetic state is stabilized for moderate values of the applied pressure (of the order of 1.6 kbar). A large linear term in the specific heat, which decreases regularly with increasing pressure, is observed in this phase. It is ascribed to giant spin fluctuations associated with a magnetic-non magnetic instability and a strong geometrical spin frustration.

  8. Paramagnetic relaxation effects in perturbed angular correlations for arbitrary electronic relaxation time

    Chopin, C.; Spanjaard, D.; Hartmann-Boutron, F.

    1975-01-01

    Previous perturbation treatments of paramagnetic relaxation effects in γγ PAC were limited to the case of very short electronic relaxation times. This limitation is circumvented by invoking a new perturbation theory recently elaborated by Hirst and others for handling relaxation effects in Moessbauer spectra. Under the assumption of spherical electronic relaxation the perturbation factors are computed as functions of certain relaxation parameters which are directly related to the microscopic relaxation Hamiltonian. The results are compared to those of the stochastic theory of Scherer and Blume [fr

  9. Dependence of adenine isolation efficiency on the chain length evidenced using paramagnetic particles and voltammetry measurements

    Huska, Dalibor [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Adam, Vojtech [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Department of Animal Nutrition and Forage Production, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Zemedelska 1, CZ-613 00 Brno (Czech Republic); Trnkova, Libuse [Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-625 00 Brno (Czech Republic); Kizek, Rene [Department of Chemistry and Biochemistry, Faculty of Agronomy, Mendel University of Agriculture and Forestry, Zemedelska 1, CZ-613 00 Brno (Czech Republic)], E-mail: kizek@sci.muni.cz

    2009-05-15

    The main aim of this work was to study the dependence of oligoadenine isolation efficiency on the chain length by using paramagnetic particles covered by homo-deoxythymidines ((dT)25) with subsequent detection by adsorptive transfer technique coupled with square wave voltammetry. For this purpose, the oligonucleotides of the length A5, A10, A15, A20, A25, A30, A35, A40 and poly(A) in various concentrations were chosen. We determined that the isolation efficiency defined as 'isolated oligonucleotide concentration'/'given oligonucleotide concentration' was about 55% on average. Sequence A25 demonstrated the best binding onto microparticles surface.

  10. Degradation of edible oil during food processing by ultrasound: electron paramagnetic resonance, physicochemical, and sensory appreciation.

    Pingret, Daniella; Durand, Grégory; Fabiano-Tixier, Anne-Sylvie; Rockenbauer, Antal; Ginies, Christian; Chemat, Farid

    2012-08-08

    During ultrasound processing of lipid-containing food, some off-flavors can be detected, which can incite depreciation by consumers. The impacts of ultrasound treatment on sunflower oil using two different ultrasound horns (titanium and pyrex) were evaluated. An electron paramagnetic resonance study was performed to identify and quantify the formed radicals, along with the assessment of classical physicochemical parameters such as peroxide value, acid value, anisidine value, conjugated dienes, polar compounds, water content, polymer quantification, fatty acid composition, and volatiles profile. The study shows an increase of formed radicals in sonicated oils, as well as the modification of physicochemical parameters evidencing an oxidation of treated oils.

  11. Role of paramagnetic polyconjugated clusters in lignin antioxidant activity (in vitro)

    Dizhbite, T; Ponomarenko, J; Andersone, A; Dobele, G; Lauberts, M; Krasilnikova, J; Telysheva, G; Mironova-Ulmane, N

    2012-01-01

    Using physico-chemical methods (EPR, SEC, Py-GC/MS and UV/VIS spectroscopy) and wet chemical analysis, the characteristics of 6 hardwood lignins in terms of functionality, molecular weight and composition of lignin substructures were determined and considered together with the results of DPPH., ABTS. + and O 2 . − antioxidant assays with the aim to understand the relationships governing antioxidant properties of lignin. The strong positive linear correlation between lignin antioxidant capacity in the three assays used and the extent of conjugation of paramagnetic polyconjugated clusters in lignin macromolecules was found. The biological activity of the most active alkaline lignins was assessed by in vitro experiment with human blood.

  12. Investigations of a new nanostructured Si-material by spectral response and electron paramagnetic resonance

    Kuznicki, Z.T.; Ley, M. [Laboratoire PHASE, CNRS UPR 292, 23 rue du Loess, F-67037 Strasbourg cedex 2 (France); Turek, P.; Bernard, M. [Institut Charles Sadron, CNRS UPR 22, 6 rue Boussingault, F-67083 Strasbourg cedex (France)

    2002-08-01

    Electron spin resonance (or electron paramagnetic resonance) was applied to analyze multi-interface solar cells with an active amorphized substructure inserted in the emitter. The nanostructure was realized by P ion implantation followed by an adequate thermal treatment to yield very sharp a-Si/c-Si heterointerfaces. The authors have investigated especially the substructure and the transition zones between the two Si phases, which is particularly interesting because of the stress induced by the density difference of the two Si phases. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  13. Retrospective dosimetry of nail by Electron Paramagnetic Resonance; Dosimetria retrospectiva de unha por Ressonancia Paramagnetica Eletronica

    Giannoni, Ricardo A., E-mail: giannoni@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Rodrigues Junior, Orlando, E-mail: rodrijr@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    The purpose of this study is to characterize samples of human nails, subjected to irradiation of high doses through Technical Electron Paramagnetic Resonance (EPR). The goal is to establish a dose/response relationship in order to assess dose levels absorbed by individuals exposed in radiation accidents situations, retrospectively. Samples of human nails were irradiated with gamma radiation, and received a dose of 20 Gy. EPR measurements performed on samples before irradiation identified EPR signals associated with defects caused by the mechanical action of the sample collection. After irradiation other species of free radicals, associated with the action of gamma radiation, have been identified.

  14. Improving the calculation of electron paramagnetic resonance hyperfine coupling tensors for d-block metals

    Hedegård, Erik Donovan; Kongsted, Jacob; Sauer, Stephan P. A.

    2012-01-01

    Calculation of hyperfine coupling constants (HFCs) of Electron Paramagnetic Resonance from first principles can be a beneficial compliment to experimental data in cases where the molecular structure is unknown. We have recently investigated basis set convergence of HFCs in d-block complexes...... and obtained a set of basis functions for the elements Sc–Zn, which were saturated with respect to both the Fermi contact and spin-dipolar components of the hyperfine coupling tensor [Hedeg°ard et al., J. Chem. Theory Comput., 2011, 7, pp. 4077-4087]. Furthermore, a contraction scheme was proposed leading...

  15. Dependence of adenine isolation efficiency on the chain length evidenced using paramagnetic particles and voltammetry measurements

    Huska, Dalibor; Adam, Vojtech; Trnkova, Libuse; Kizek, Rene

    2009-01-01

    The main aim of this work was to study the dependence of oligoadenine isolation efficiency on the chain length by using paramagnetic particles covered by homo-deoxythymidines ((dT)25) with subsequent detection by adsorptive transfer technique coupled with square wave voltammetry. For this purpose, the oligonucleotides of the length A5, A10, A15, A20, A25, A30, A35, A40 and poly(A) in various concentrations were chosen. We determined that the isolation efficiency defined as 'isolated oligonucleotide concentration'/'given oligonucleotide concentration' was about 55% on average. Sequence A25 demonstrated the best binding onto microparticles surface.

  16. The dependence of magnetic ordering temperature in amorphous semiconductors on paramagnetic centre concentration

    Khokhlov, A.F.; Mashin, A.I.; Satanin, A.M.

    1981-01-01

    In silicon amorphized by ion implantation (a-Si) the dependence of magnetic ordering temperature (theta) on localized spin concentration (Nsub(s)) is studied by EPR method. Nsub(s) changes by varying the Ne + ion dose from 6x10 14 to 2x10 17 cm -2 and sample annealing. From the comparison of the data obtained with literature ones conclusions are made about the existence of two critical values of Nsub(s) in a-Si (approximately 10 19 and approximately 2x10 20 cm -3 ), when a transition occurs from paramagnetism to antiferromagnetism (at T < theta) and from antiferromagnetism to ferromagnetism, respectively. (author)

  17. Ocular Biometrics of Myopic Eyes With Narrow Angles.

    Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

    2016-02-01

    The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

  18. Acquisition and visualization techniques for narrow spectral color imaging.

    Neumann, László; García, Rafael; Basa, János; Hegedüs, Ramón

    2013-06-01

    This paper introduces a new approach in narrow-band imaging (NBI). Existing NBI techniques generate images by selecting discrete bands over the full visible spectrum or an even wider spectral range. In contrast, here we perform the sampling with filters covering a tight spectral window. This image acquisition method, named narrow spectral imaging, can be particularly useful when optical information is only available within a narrow spectral window, such as in the case of deep-water transmittance, which constitutes the principal motivation of this work. In this study we demonstrate the potential of the proposed photographic technique on nonunderwater scenes recorded under controlled conditions. To this end three multilayer narrow bandpass filters were employed, which transmit at 440, 456, and 470 nm bluish wavelengths, respectively. Since the differences among the images captured in such a narrow spectral window can be extremely small, both image acquisition and visualization require a novel approach. First, high-bit-depth images were acquired with multilayer narrow-band filters either placed in front of the illumination or mounted on the camera lens. Second, a color-mapping method is proposed, using which the input data can be transformed onto the entire display color gamut with a continuous and perceptually nearly uniform mapping, while ensuring optimally high information content for human perception.

  19. Intramyocardial arterial narrowing in dogs with subaortic stenosis.

    Falk, T; Jönsson, L; Pedersen, H D

    2004-09-01

    Earlier studies have described intramyocardial arterial narrowing based on hyperplasia and hypertrophy of the vessel wall in dogs with subaortic stenosis (SAS). In theory, such changes might increase the risk of sudden death, as they seem to do in heart disease in other species. This retrospective pathological study describes and quantifies intramyocardial arterial narrowing in 44 dogs with naturally occurring SAS and in eight control dogs. The majority of the dogs with SAS died suddenly (n=27); nine had died or been euthanased with signs of heart failure and eight were euthanased without clinical signs. Dogs with SAS had significantly narrower intramyocardial arteries (Pdogs. Male dogs and those with more severe hypertrophy had more vessel narrowing (P=0.02 and P=0.02, respectively), whereas dogs with dilated hearts had slightly less pronounced arterial thickening (P=0.01). Arterial narrowing was not related to age, but fibrosis increased with age (P=0.047). Dogs that died suddenly did not have a greater number of arterial changes than other dogs with SAS. This study suggests that most dogs with SAS have intramyocardial arterial narrowing and that the risk of dying suddenly is not significantly related to the overall degree of vessel obliteration.

  20. Narrowing of electromagnetically induced transparency resonance in a Doppler-broadened medium

    Javan, Ali; Kocharovskaya, Olga; Lee Hwang; Scully, Marlan O.

    2002-01-01

    We derive an analytic expression for the linewidth of electromagnetically induced transparency (EIT) resonance in a Doppler-broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser-induced line narrowing effect described by Feld and Javan. In the limit of high intensity we recover the usual power-broadening case where the EIT linewidth is proportional to the intensity and inversely proportional to the Doppler width