19,358 research outputs found

    Test evaluation of fuel cell catalysts Final report

    Get PDF
    Carbides, bromides,nitrides,and alloys tested for catalytic characteristics for ammonia and carbon nonoxide in fuel cell electrolyte

    The connection between metallicity and metal-line kinematics in (sub-)damped Lyman-alpha systems

    Full text link
    A correlation between the metallicity, [M/H], and rest-frame MgII equivalent width, EW, is found from 49 DLAs and strong sub-DLAs drawn from the literature over the redshift range 0.2<z_abs<2.6. The correlation is significant at 4.2 sigma and improves to 4.7 sigma when the mild evolution of [M/H] with redshift is taken into account. Even when including only the 26 DLAs (i.e. excluding sub-DLAs) which have Zn metallicities and EW>0.7A, the correlation remains at >3 sigma significance. Since the MgII2796 transition is predominantly saturated in DLAs (which always have EW greater than 0.3A), EW is far more sensitive to the kinematic spread of the metal velocity components across the absorption profile than it is to [M/H]. Thus, the observed [M/H]--EW correlation points to a strong link between the absorber metallicity and the mechanism for producing and dispersing the velocity components. We also note that approximately half of the 13 known molecular hydrogen absorbers have very high EW and very broad velocity structures which show characteristics usually associated with outflows. Follow-up ultraviolet- and blue-sensitive high-resolution spectra of high-EW systems, initially identified in low-resolution spectra, may therefore yield a large number of new H_2 discoveries.Comment: 9 pages, 2 figures (3 EPS files). Accepted by MNRA

    Multiplexed communication over a high-speed quantum channel

    Get PDF
    In quantum information systems it is of particular interest to consider the best way in which to use the non-classical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are amongst the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analogue bandwidth. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4 GHz comb of vacuum squeezing produced by a sub-threshold OPO, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel

    Temperature dependent asymmetry of the nonlocal spin-injection resistance: evidence for spin non-conserving interface scattering

    Get PDF
    We report nonlocal spin injection and detection experiments on mesoscopic Co-Al2O3-Cu spin valves. We have observed a temperature dependent asymmetry in the nonlocal resistance between parallel and antiparallel configurations of the magnetic injector and detector. This strongly supports the existence of a nonequilibrium resistance that depends on the relative orientation of the detector magnetization and the nonequilibrium magnetization in the normal metal providing evidence for increasing interface spin scattering with temperature.Comment: 5 pages, 4 figures, accepted for publication in PRL, minor corrections (affiliation, acknowledgements, typo

    The Inflation-Hedging Effectiveness of Real Estate

    Get PDF
    Inflation has become one of the predominant financial concerns of the late twentieth century. In the late 1970s, public opinion polls ranked inflation as the number one problem in the United States. While the rate of inflation has slowed since the late 1970s, inflation is still present and many investors expect a resurgence of inflation to higher levels in the near to immediate future. This continued concern about inflation has led to an increased search and evaluation of investments that will protect investors from inflation. Assets that have the ability to protect investors from the effects of inflation are generally labeled inflation hedges. Real estate has been regarded as one of the best inflation hedges of past years. While there has been research in the past evaluating this possibility and some recent research using only business real estate, no current research on residential real estate or farmland as inflation hedges exists. This study examines the inflation-hedging effectiveness of residential real estate, farmland, and business real estate (with a different data set) as individual assets and in a portfolio context for 1960-86.

    A Multiwavelength Analysis of the Strong Lensing Cluster RCS 022434-0002.5 at z=0.778

    Full text link
    We present the results of two (101 ks total) Chandra observations of the z=0.778 optically selected lensing cluster RCS022434-0002.5, along with weak lensing and dynamical analyses of this object. An X-ray spectrum extracted within R(2500) (362 h(70)^(-1) kpc) results in an integrated cluster temperature of 5.1 (+0.9,-0.5) keV. The surface brightness profile of RCS022434-0002.5 indicates the presence of a slight excess of emission in the core. A hardness ratio image of this object reveals that this central emission is primarily produced by soft X-rays. Further investigation yields a cluster cooling time of 3.3 times 10^9 years, which is less than half of the age of the universe at this redshift given the current LCDM cosmology. A weak lensing analysis is performed using HST images, and our weak lensing mass estimate is found to be in good agreement with the X-ray determined mass of the cluster. Spectroscopic analysis reveals that RCS022434-0002.5 has a velocity dispersion of 900 +/- 180 km/s, consistent with its X-ray temperature. The core gas mass fraction of RCS022434-0002.5 is, however, found to be three times lower than expected universal values. The radial distribution of X-ray point sources within R(200) of this cluster peaks at ~0.7 R(200), possibly indicating that the cluster potential is influencing AGN activity at that radius. Correlations between X-ray and radio (VLA) point source positions are also examined.Comment: 32 pages, 9 figures. Accepted for publication in The Astrophysical Journa

    The fluorine abundance in a Galactic Bulge AGB star measured from CRIRES spectra

    Full text link
    We present measurements of the fluorine abundance in a Galactic Bulge Asymptotic Giant Branch (AGB) star. The measurements were performed using high resolution K-band spectra obtained with the CRIRES spectrograph, which has been recently installed at ESO's VLT, together with state-of-the-art model atmospheres and synthetic spectra. This represents the first fluorine abundance measurement in a Galactic Bulge star, and one of few measurements of this kind in a third dredge-up oxygen-rich AGB star. The F abundance is found to be close to the solar value scaled down to the metallicity of the star, and in agreement with Disk giants that are comparable to the Bulge giant studied here. The measurement is of astrophysical interest also because the star's mass can be estimated rather accurately (1.4 \lesssim M/\mathrm{M}_{\sun} \lesssim 2.0). AGB nucleosynthesis models predict only a very mild enrichment of F in such low mass AGB stars. Thus, we suggest that the fluorine abundance found in the studied star is representative for the star's natal cloud, and that fluorine must have been produced at a similar level in the Bulge and in the Disk.Comment: 11 pages, 1 figure, accepted for publication by Ap

    Ultrafast carrier dynamics on Si surfaces studied by femtosecond time-resolved two-photon photoelectron spectroscopy

    Full text link
    Secondary Ion Mass spectrometry (SIMS) has been generally used in the field of material sciences. In recent years, it has also been applied for molecular imaging of biological samples. Nevertheless, molecular ions derived from the large molecules (more than 1 kDa) were detected with very low sensitivity. Plasma desorption mass spectrometry (PDMS) is known as mass spectrometry for large organic molecule. In PDMS, fission fragments bombard samples and the impact induces molecular ionization by electronic excitation. Large organic molecules are detected by using swift heavy ions in SIMS. In this work, 6 MeV Cu4+ we irradiated angiotensin II, a class of peptides. The intact molecular ions generated by swift heavy ion irradiation were analyzed by time‐of‐flight (TOF) measurement. The yields are compared with some other probe ions, bismuth or flurane. Swift heavy ion bombardment ionized large organic molecules more effectively than other probes. Therefore, high energy ion can be applied in high resolution molecular imaging

    Sexuality and Disability in Rehabilitation Counseling Curricula: Rehabilitation Counselor Educators’ Attitudes, Comfort, and Knowledge

    Get PDF
    Purpose: To examine the attitudes, knowledge, and comfort levels of rehabilitation counselor educators towards sexuality and disability, and to determine if significant differences exist within variables. Method: Data was collected from a sample of rehabilitation counselor educators (N=27) via an internet-based survey. The Knowledge, Comfort, Approach and Attitudes towards Sexuality Scale (KCAASS) and demographic questionnaire was disseminated to collect data. A MANOVA was conducted to examine if there was a relationship among the variables of attitudes, knowledge, comfort, age, gender, and ethnicity. Results: Results indicates educators having high comfort levels and positive attitudes towards sexuality and disability. The mean for knowledge was low indicating a lower level of knowledge of sexuality and disability. Results indicate that there was no variance among the means of the categorical variables. The only variation that existed within the categorical variables was the gender of the participant. Conclusion: Further research is warranted to examine the specific needs of educators, students, and graduate programs, as well as exploring differences based upon institutional settings. Future qualitative research in sexuality and disability may also generate testimonials and theories from the perspective of students and educators in expressing their needs. The inclusion of human sexuality within various academic levels of rehabilitation education is warranted to increase competence of both students and educators. Keywords: Sexuality, Rehabilitation, and Counselor Educatio
    • …
    corecore