WorldWideScience

Sample records for narrow-band photoelectric photometry

  1. 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.

  2. A Method for Transferring Photoelectric Photometry Data from Apple II+ to IBM PC

    Powell, Harry D.; Miller, James R.; Stephenson, Kipp

    1989-06-01

    A method is presented for transferring photoelectric photometry data files from an Apple II computer to an IBM PC computer in a form which is compatible with the AAVSO Photoelectric Photometry data collection process.

  3. Photoelectric UBV and DDO photometry of NGC 5138

    Claria, J.J.

    1980-01-01

    Results of UBV photoelectric photometry in NGC 5138 are presented for 50 stars brighter than 14.0 mag. In addition, four probable red giants were also observed in the DDO system. Sixteen stars previously considered members by Lindoff (1972), were found not to be physically connected with the cluster. NGC 5138 is located 1.80 kpc from the Sun and the visual interstellar absorption determined from the reddened B stars amounts to Asub(v) = 0.75 mag. There of the four red stars observed in the DDO system were found to be cluster members. The mean cyanogen anomaly is = 0.043 +- 0.018(m.e.), which implies that NGC 5138 is richer in CN than the field K giants in the solar neighbourhodd, but poorer than the Hyades giants. The cluster age is estimated to be approx. 1.5 x 10 8 yr. (orig.)

  4. The AAVSO Photoelectric Photometry Program in its Scientific and Socio-Historic Context

    Percy, John R.

    2011-05-01

    Photoelectric photometry began in the 1900s through the work of Guthnick, Stebbins, and others who constructed and used photometers based on the recently-discovered photoelectric effect. The mid 20th century saw a confluence of several areas of amateur interest: astronomy, telescope making, radio and electronics, and general interest in space. This is the time when AAVSO photoelectric photometry (PEP) began, with observers using mostly hand-built photometers on hand-built telescopes. The 1980s brought a revolution: affordable off-the-shelf solid-state photometers, and infrastructure such as the International Amateur-Professional Photoelectric Photometry (IAPPP) conferences, books, and journal. The AAVSO developed a formal PEP program in the early 1980s. Its emphasis was on long-term monitoring of pulsating red giants. It was competing, not always successfully, with programs such as active sun-like binaries (RS CVn stars) which offered "instant gratification" in the form of publicity and quick publications. Nevertheless, the AAVSO PEP program has, through careful organization, motivation, and feedback to observers, produced extensive scientific results. In this presentation, I shall describe, as examples, my own work, its scientific significance, its educational benefit to dozens of my students, and its satisfaction to the observers. To some extent, the AAVSO PEP program has been superceded by its CCD program, but there is still a useful place for ongoing PEP observations of thousands of variable stars. Reference: http://www.aavso.org/sites/default/files/newsletter/PEP/lastpepnl.pdf Acknowledgements: I thank NSERC Canada for research support, my students, and AAVSO staff and observers, especially Howard Landis.

  5. Optical photometry of galaxies

    Comte, G.

    1981-01-01

    The present status of the optical and near-infrared photometry of galaxies is reviewed. Part I introduces to the goals and general methods of both photographic surface photometry and integrated multicolor aperture photoelectric photometry for extended stellar systems, with a summary of the necessary corrections to the observed magnitudes and colors. Part II (surface photometry) summarizes recent results on the empirical luminosity laws for spheroidal systems and the separation of components in disk-plus-bulge systems. Part III (color problems) discusses integrated color effects (color and gas content, color-absolute magnitude relation for early-type systems, colors of interacting galaxies) and color gradient across spheroidal and disk galaxies. In part IV are summarized some constraints on the luminosity function of the stellar population in spheroidal systems given by narrow-band photometry [fr

  6. Photoelectric UBV-photometry of the In(YY) DR Tauri-type young star in 1982-1986

    Kolotilov, E.A.

    1987-01-01

    The results of photoelectric UBV-photometry carried out in 1982-1986 for DR TAU - the star which undergone nova-like brightness increase in 1965-1980 - are presented. The brightness variations of the star during the post-maximum period include several days lasting flares and much more rare deep minima. The averaged colour-brightness relations are as follows: the higher brightness, the bluer B - V colour and the redder U - B colour. However the fast variations on a time scale of days do not always follow this relation. The observed pattern of variability of DR Tau is in agreement with the model of young stars activity (Grinin, 1980) proposing the appearance of hot spots in stellar atmosphere due to accretion of gas. Some arguments for the binarity of DR Tau are presented

  7. 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.

  8. 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

  9. 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

  10. 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

  11. Predicting soil nitrogen content using narrow-band indices from ...

    Optimal fertiliser applications for sustainable forest stand productivity management, whilst protecting the environment, is vital. This study estimated soil nitrogen content using leaf-level narrow-band vegetation indices derived from a hand-held 350–2 500 nm spectroradiometer. Leaf-level spectral data were collected and ...

  12. Nonstationary Narrow-Band Response and First-Passage Probability

    Krenk, Steen

    1979-01-01

    The notion of a nonstationary narrow-band stochastic process is introduced without reference to a frequency spectrum, and the joint distribution function of two consecutive maxima is approximated by use of an envelope. Based on these definitions the first passage problem is treated as a Markov po...

  13. Narrow-Band Imaging: Clinical Application in Gastrointestinal Endoscopy

    Sandra Barbeiro

    2018-03-01

    Full Text Available Narrow-band imaging is an advanced imaging system that applies optic digital methods to enhance endoscopic images and improves visualization of the mucosal surface architecture and microvascular pattern. Narrow-band imaging use has been suggested to be an important adjunctive tool to white-light endoscopy to improve the detection of lesions in the digestive tract. Importantly, it also allows the distinction between benign and malignant lesions, targeting biopsies, prediction of the risk of invasive cancer, delimitation of resection margins, and identification of residual neoplasia in a scar. Thus, in expert hands it is a useful tool that enables the physician to decide on the best treatment (endoscopic or surgical and management. Current evidence suggests that it should be used routinely for patients at increased risk for digestive neoplastic lesions and could become the standard of care in the near future, at least in referral centers. However, adequate training programs to promote the implementation of narrow-band imaging in daily clinical practice are needed. In this review, we summarize the current scientific evidence on the clinical usefulness of narrow-band imaging in the diagnosis and characterization of digestive tract lesions/cancers and describe the available classification systems.

  14. US images encoding envelope amplitude following narrow band filtering

    Sommer, F.G.; Stern, R.A.; Chen, H.S.

    1986-01-01

    Ultrasonic waveform data from phantoms having differing scattering characteristics and from normal and cirrhotic human liver in vivo were recorded within a standardized dynamic range and filtered with narrow band filters either above or below the mean recorded ultrasonic center frequency. Images created by mapping the amplitudes of received ultrasound following such filtration permitted dramatic differentiation, not discernible in conventional US images, of phantoms having differing scattering characteristics, and of normal and cirrhotic human livers

  15. Narrow-band radio flares from red dwarf stars

    White, S.M.; Kundu, M.R.; Jackson, P.D.

    1986-12-01

    VLA observations of narrow-band behavior in 20 cm flares from two red dwarf stars, L726 - 8A and AD Leo, are reported. The flare on L726 - 8A was observed at 1415 and 1515 MHz; the flux and the evolution differed significantly at the two frequencies. The flare on AD Leo lasted for 2 hr at 1415 MHz but did not appear at 1515 MHz. The AD Leo flare appears to rule out a source drifting through the stellar corona and is unlikely to be due to plasma emission. In the cyclotron maser model the narrow-band behavior reflects the range of magnetic fields present within the source. The apparent constancy of this field for 2 hr is difficult to understand if magnetic reconnection is the source of energy for the flare. The consistent polarization exhibited by red dwarf flares at 20 cm may be related to stellar activity cycles, and changes in this polarization will permit measuring the length of these cycles. 22 references.

  16. Narrow-band radio flares from red dwarf stars

    White, Stephen M.; Kundu, Mukul R.; Jackson, Peter D.

    1986-01-01

    VLA observations of narrow-band behavior in 20 cm flares from two red dwarf stars, L726 - 8A and AD Leo, are reported. The flare on L726 - 8A was observed at 1415 and 1515 MHz; the flux and the evolution differed significantly at the two frequencies. The flare on AD Leo lasted for 2 hr at 1415 MHz but did not appear at 1515 MHz. The AD Leo flare appears to rule out a source drifting through the stellar corona and is unlikely to be due to plasma emission. In the cyclotron maser model the narrow-band behavior reflects the range of magnetic fields present within the source. The apparent constancy of this field for 2 hr is difficult to understand if magnetic reconnection is the source of energy for the flare. The consistent polarization exhibited by red dwarf flares at 20 cm may be related to stellar activity cycles, and changes in this polarization will permit measuring the length of these cycles.

  17. Narrow band interference cancelation in OFDM: Astructured maximum likelihood approach

    Sohail, Muhammad Sadiq

    2012-06-01

    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 with the frequency grid of the ZP-OFDM system. The proposed structure based technique uses the fact that the NBI signal is sparse as compared to the ZP-OFDM signal in the frequency domain. The structure is also useful in reducing the computational complexity of the proposed method. The paper also presents a data aided approach for improved NBI estimation. The suitability of the proposed method is demonstrated through simulations. © 2012 IEEE.

  18. Implementation of Industrial Narrow Band Communication System into SDR Concept

    A. Prokes

    2008-12-01

    Full Text Available The rapid expansion of the digital signal processing has penetrated recently into a sphere of high performance industrial narrow band communication systems which had been for long years dominated by the traditional analog circuit design. Although it brings new potential to even increase the efficiency of the radio channel usage it also forces new challenges and compromises radio designers have to face. In this article we describe the design of the IF sampling industrial narrowband radio receiver, optimize a digital receiver structure implemented in a single FPGA circuit and study the performance of such radio receiver architecture. As an evaluation criterion the communication efficiency in form of maximum usable receiver sensitivity, co-channel rejection, adjacent channel selectivity and radio blocking measurement have been selected.

  19. 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

  20. The narrow-band imaging examination method in otorhinolaryngology

    Robert Šifrer

    2013-10-01

    Full Text Available Early diagnostics could improve the prognosis of patients with squamous-cell carcinomas of the head and neck. Narrow-Band Imaging (NBI is the latest examination method in the group of biologic endoscopies. NBI improves the distinction between malignant and benign mucosal lesions. Early suspect oncologic lesions that may otherwise be missed by normal white light illumination can also be diagnosed. The biggest benefit of NBI technology is achieved by using it together with a HDTV camera that enables better contrast and higher resolution. NBI is based on better imaging of superficial mucosal vasculature. The biologic potential of mucosal lesions could be predicted from vascular changes. The colour of normal mucosa under NBI is blue and green and the vessels show no pathological features. Well-demarcated brownish areas and scattered thick dark spots and abnormal winding and branching out of vessels on the mucosa are all oncologically suspicious features. Authors report the experience from literature on the use of NBI to identify carcinomas of the oral cavity, epipharynx, oropharynx, hypopharynx and larynx and evaluation of unknown primaries. In addition, the literature reports the benefit of NBI in identifying early stage carcinomas in previously irradiated patients. Persistence and recurrence of carcinoma and the development of new primary tumour could easily be missed by using only standard white-light illumination. The method proved to be highly sensitive and specific for predicting malignant changes in the above-mentioned circumstances. Authors report their own experience with NBI technology as well. For further improvement of the method, new technologic development is expected to enable the connection of NBI and HDTV with flexible endoscopes.

  1. Deep narrow band imagery of the diffuse ISM in M33

    Hester, J. Jeff; Kulkarni, Shrinivas R.

    1990-01-01

    Very deep narrow band images were obtained for several fields in the local group spiral galaxy M33 using a wide field reimaging Charge Coupled Device (CCD) camera on the 1.5 m telescope at Palomar Observatory. The reimaging system uses a 306 mm collimator and a 58 mm camera lens to put a 16 minute by 16 minute field onto a Texas Instruments 800 x 800 pixel CCD at a resolution of 1.2 arcseconds pixel (-1). The overall system is f/1.65. Images were obtained in the light of H alpha (S II) lambda lambda 6717, 6731, (O III) lambda 5007, and line-free continuum bands 100A wide, centered at 6450A and 5100A. Assuming a distance of 600 kpc to M33 (Humphreys 1980, Ap. J., 241, 587), this corresponds to a linear scale of 3.5 pc pixel (-1), and a field size of 2.8 kpc x 2.8 kpc. Researchers discuss the H alpha imagery of a field centered approx. equal to 8 minutes NE of the nucleus, including the supergiant HII region complex NGC 604. Two 2000 second H alpha images and two 300 second red continuum images were obtained of two slightly offset fields. The fields were offset to allow for discrimination between real emission and possible artifacts in the images. All images were resampled to align them with one of the H alpha frames. The continuum images were normalized to the line images using the results of aperture photometry on a grid of stars in the field, then the rescaled continuum data were directly subtracted from the line data.

  2. Active halo control through narrow-band excitation with the ADT at injection

    Wagner, Joschka; Garcia Morales, Hector; Redaelli, Stefano; Valentino, Gianluca; Valuch, Daniel; CERN. Geneva. ATS Department

    2016-01-01

    During this MD (MD1388), the capabilities of an active halo control for beam tail depletion in the LHC were tested. The studied method relies on using the Transverse Damper (ADT) to perform a narrow-band excitation.

  3. An enhanced narrow-band imaging method for the microvessel detection

    Yu, Feng; Song, Enmin; Liu, Hong; Wan, Youming; Zhu, Jun; Hung, Chih-Cheng

    2018-02-01

    A medical endoscope system combined with the narrow-band imaging (NBI), has been shown to be a superior diagnostic tool for early cancer detection. The NBI can reveal the morphologic changes of microvessels in the superficial cancer. In order to improve the conspicuousness of microvessel texture, we propose an enhanced NBI method to improve the conspicuousness of endoscopic images. To obtain the more conspicuous narrow-band images, we use the edge operator to extract the edge information of the narrow-band blue and green images, and give a weight to the extracted edges. Then, the weighted edges are fused with the narrow-band blue and green images. Finally, the displayed endoscopic images are reconstructed with the enhanced narrow-band images. In addition, we evaluate the performance of enhanced narrow-band images with different edge operators. Experimental results indicate that the Sobel and Canny operators achieve the best performance of all. Compared with traditional NBI method of Olympus company, our proposed method has more conspicuous texture of microvessel.

  4. B and V photoelectric photometry and light curve solution of the interacting binary systems HI Puppis, BL Eridani and SY Horologii

    Kern, J.R.

    1985-01-01

    The first photoelectric observations of the eclipsing binary systems HI Puppis, BL Eridani, and SY Horologii were obtained and complete B and V light curves are presented. Improved light elements were derived for all three systems. The light curves of HI Puppis were analyzed by the three different computer models of Wilson and Devinney (1971), Binnendijk (1977), and Wood (1971) to get the geometrical and photometric elements of the system. HI Puppis, whose light curves show a total eclipse at secondary minimum, is shown to be a classic A-Type W Ursae Majoris system. The geometrical and photometric elements of BL Eridani were obtained from the analysis of the light curves using the method of Wilson and Devinney. The asymmetric nature of the light curve is treated as being due to the presence of an underluminous starspot on the primary component. The light curves of BL Eri show secondary eclipse to be total. The system is found to be a near contact system with the primary component filling its Roche lobe and the secondary nearly filling its lobe with a fill-out ratio of approximately 1.0. The light curves of SY Horologii were also subjected to the model of Wilson and Devinney. Both primary and secondary eclipses are partial

  5. Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms

    Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

    2016-12-01

    Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

  6. Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms.

    Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

    2016-12-16

    Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

  7. Application of narrow-band television to industrial and commercial communications

    Embrey, B. C., Jr.; Southworth, G. R.

    1974-01-01

    The development of narrow-band systems for use in space systems is presented. Applications of the technology to future spacecraft requirements are discussed along with narrow-band television's influence in stimulating development within the industry. The transferral of the technology into industrial and commercial communications is described. Major areas included are: (1) medicine; (2) education; (3) remote sensing for traffic control; and (5) weather observation. Applications in data processing, image enhancement, and information retrieval are provided by the combination of the TV camera and the computer.

  8. An Optimized, Grid Independent, Narrow Band Data Structure for High Resolution Level Sets

    Nielsen, Michael Bang; Museth, Ken

    2004-01-01

    enforced by the convex boundaries of an underlying cartesian computational grid. Here we present a novel very memory efficient narrow band data structure, dubbed the Sparse Grid, that enables the representation of grid independent high resolution level sets. The key features our new data structure are...

  9. On the joint distribution of excursion duration and amplitude of a narrow-band Gaussian process

    Ghane, Mahdi; Gao, Zhen; Blanke, Mogens

    2018-01-01

    of amplitude and period are limited to excursion through a mean-level or to describe the asymptotic behavior of high level excursions. This paper extends the knowledge by presenting a theoretical derivation of probability of wave exceedance amplitude and duration, for a narrow-band Gaussian process......The probability density of crest amplitude and of duration of exceeding a given level are used in many theoretical and practical problems in engineering. The joint density is essential for design of constructions that are subjected to waves and wind. The presently available joint distributions...... distribution, as expected, and that the marginal distribution of excursion duration works both for asymptotic and non-asymptotic cases. The suggested model is found to be a good replacement for the empirical distributions that are widely used. Results from simulations of narrow-band Gaussian processes, real...

  10. Perturbation method for calculation of narrow-band impedance and trapped modes

    Heifets, S.A.

    1987-01-01

    An iterative method for calculation of the narrow-band impedance is described for a system with a small variation in boundary conditions, so that the variation can be considered as a perturbation. The results are compared with numeric calculations. The method is used to relate the origin of the trapped modes with the degeneracy of the spectrum of an unperturbed system. The method also can be applied to transverse impedance calculations. 6 refs., 6 figs., 1 tab

  11. Generation of tunable narrow-band surface-emitted terahertz radiation in periodically poled lithium niobate.

    Weiss, C; Torosyan, G; Avetisyan, Y; Beigang, R

    2001-04-15

    Generation of tunable narrow-band terahertz (THz) radiation perpendicular to the surface of periodically poled lithium niobate by optical rectification of femtosecond pulses is reported. The generated THz radiation can be tuned by use of different poling periods and different observation angles, limited only by the available bandwidth of the pump pulse. Typical bandwidths were 50-100 GHz, depending on the collection angle and the number of periods involved.

  12. Double symbol error rates for differential detection of narrow-band FM

    Simon, M. K.

    1985-01-01

    This paper evaluates the double symbol error rate (average probability of two consecutive symbol errors) in differentially detected narrow-band FM. Numerical results are presented for the special case of MSK with a Gaussian IF receive filter. It is shown that, not unlike similar results previously obtained for the single error probability of such systems, large inaccuracies in predicted performance can occur when intersymbol interference is ignored.

  13. Optical observations of the nearby galaxy IC342 with narrow band [SII] and Hα filters. I

    Vučetić M.M.

    2013-01-01

    Full Text Available We present observations of a portion of the nearby spiral galaxy IC342 using narrow band [SII] and Hα filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, Hα and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 5 times higher than previously known in these two parts of the galaxy. [Projekat Ministarstva nauke Republike Srbije, br. 176005: Emission nebulae: structure and evolution

  14. Observations of the Galaxy NGC 3077 in the Narrow-Band [S II] and Hα Filters

    Andjelić M.

    2011-09-01

    Full Text Available We present observations of the H I tidal arm near a dwarf galaxy NGC 3077 (member of the M81 galaxy group in the narrow-band [S II] and Hα filters. Observations were carried out in 2011 March with the 2 m RCC telescope at the NAO Rozhen, Bulgaria. Our search for possible supernova remnant candidates (identified as sources with enhanced [S II] emission relative to their Hα emission in this region yielded no sources of this kind. Nevertheless, we found a number of objects with significant Hα emission that probably represent uncatalogued, low brightness H II regions.

  15. Control of fibre laser mode-locking by narrow-band Bragg gratings

    Laegsgaard, J

    2008-01-01

    The use of narrow-band high-reflectivity fibre Bragg gratings (FBGs) as end mirrors in a fibre laser cavity with passive mode-locking provided by a semiconductor saturable absorber mirror (SESAM) is investigated numerically. The FBG is found to control the energy range of stable mode-locking, which may be shifted far outside the regime of SESAM saturation by a suitable choice of FBG and cavity length. The pulse shape is controlled by the combined effects of FBG dispersion and self-phase modulation in the fibres, and a few ps pulses can be obtained with standard uniform FBGs

  16. Enhancing Coverage in Narrow Band-IoT Using Machine Learning

    Chafii , Marwa; Bader , Faouzi; Palicot , Jacques

    2018-01-01

    International audience; —Narrow Band-Internet of Thing (NB-IoT) is a recently proposed technology by 3GPP in Release-13. It provides low energy consumption and wide coverage in order to meet the requirements of its diverse applications that span social, industrial and environmental aspects. Increasing the number of repetitions of the transmission has been selected as a promising approach to enhance the coverage in NB-IoT up to 164 dB in terms of maximum coupling loss for uplink transmissions,...

  17. All-mechanical quantum noise cancellation for accelerometry: broadband with momentum measurements, narrow band without

    Jacobs, Kurt; Balu, Radhakrishnan; Tezak, Nikolas; Mabuchi, Hideo

    2016-01-01

    We show that the ability to make direct measurements of momentum, in addition to the usual direct measurements of position, allows a simple configuration of two identical mechanical oscillators to be used for broadband back-action-free force metrology. This would eliminate the need for an optical reference oscillator in the scheme of Tsang and Caves (2010 Phys. Rev. Lett.  105 123601), along with its associated disadvantages. We also show that if one is restricted to position measurements alone then two copies of the same two-oscillator configuration can be used for narrow-band back-action-free force metrology. (paper)

  18. Thermal Loss Becomes an Issue for Tunable Narrow-band Antennas in Fourth Generation Handsets

    Barrio, Samantha Caporal Del; Morris, Art; Pedersen, Gert Frølund

    2015-01-01

    Antenna tuning is a very promising technique to cope with the expansion of the mobile communication frequency spectrum. Tunable antennas can address a wide range of operating frequencies, while being highly integrated. In particular, high-Q antennas (also named narrow-band antennas) are very...... compact, thus are good candidates to be embedded on fourth generation handsets. This study focuses on ‘high-Q’ tunable antennas and contributes with a characterisation of their loss mechanism, which is a major parameter in link-budget calculations. This study shows, through an example, that the tuner loss...

  19. The differences in brain activity between narrow band noise and pure tone tinnitus.

    Sven Vanneste

    Full Text Available BACKGROUND: Tinnitus is an auditory sensation characterized by the perception of sound or noise in the absence of any external sound source. Based on neurobiological research, it is generally accepted that most forms of tinnitus are attributable to maladaptive plasticity due to damage to auditory system. Changes have been observed in auditory structures such as the inferior colliculus, the thalamus and the auditory cortex as well as in non-auditory brain areas. However, the observed changes show great variability, hence lacking a conclusive picture. One of the reasons might be the selection of inhomogeneous groups in data analysis. METHODOLOGY: The aim of the present study was to delineate the differences between the neural networks involved in narrow band noise and pure tone tinnitus conducting LORETA based source analysis of resting state EEG. CONCLUSIONS: Results demonstrated that narrow band noise tinnitus patients differ from pure tone tinnitus patients in the lateral frontopolar (BA 10, PCC and the parahippocampal area for delta, beta and gamma frequency bands, respectively. The parahippocampal-PCC current density differences might be load dependent, as noise-like tinnitus constitutes multiple frequencies in contrast to pure tone tinnitus. The lateral frontopolar differences might be related to pitch specific memory retrieval.

  20. Widely tunable narrow-band coherent Terahertz radiation from an undulator at THU

    Su, X.; Wang, D.; Tian, Q.; Liang, Y.; Niu, L.; Yan, L.; Du, Y.; Huang, W.; Tang, C.

    2018-01-01

    There is anxious demand for intense widely tunable narrow-band Terahertz (THz) radiation in scientific research, which is regarded as a powerful tool for the coherent control of matter. We report the generation of widely tunable THz radiation from a planar permanent magnet undulator at Tsinghua University (THU). A relativistic electron beam is compressed by a magnetic chicane into sub-ps bunch length to excite THz radiation in the undulator coherently. The THz frequency can be tuned from 0.4 THz to 10 THz continuously with narrow-band spectrums when the undulator gap ranges from 23 mm to 75 mm. The measured pulse THz radiation energy from 220 pC bunch is 3.5 μJ at 1 THz and tens of μJ pulse energy (corresponding peak power of 10 MW) can be obtained when excited by 1 nC beam extrapolated from the property of coherent radiation. The experimental results agree well with theoretical predictions, which demonstrates a suitable THz source for the many applications that require intense and widely tunable THz sources.

  1. Ultra-narrow band perfect absorbers based on Fano resonance in MIM metamaterials

    Zhang, Ming; Fang, Jiawen; Zhang, Fei; Chen, Junyan; Yu, Honglin

    2017-12-01

    Metallic nanostructures have attracted numerous attentions in the past decades due to their attractive plasmonic properties. Resonant plasmonic perfect absorbers have promising applications in a wide range of technologies including photothermal therapy, thermophotovoltaics, heat-assisted magnetic recording and biosensing. However, it remains to be a great challenge to achieve ultra-narrow band in near-infrared band with plasmonic materials due to the large optical losses in metals. In this letter, we introduced Fano resonance in MIM metamaterials composed of an asymmetry double elliptic cylinders (ADEC), which can achieve ultra-narrow band perfect absorbers. In theoretical calculations, we observed an ultranarrow band resonant absorption peak with the full width at half maximum (FWHM) of 8 nm and absorption amplitude exceeding 99% at 930 nm. Moreover, we demonstrate that the absorption increases with the increase of asymmetry and the absorption resonant wavelength can be tuned by changing the size and arrangement of the unit cell. The asymmetry metallic nanostructure also exhibit a higher refractive sensitivity as large as 503 nm/RIU with high figure of merit of 63, which is promising for high sensitive sensors. Results of this work are desirable for various potential applications in micro-technological structures such as biological sensors, narrowband emission, photodetectors and solar thermophotovoltaic (STPV) cells.

  2. The effects of narrow-band middle infrared radiation in enhancing the antitumor activity of paclitaxel.

    Tsai, Shang-Ru; Sheu, Bor-Ching; Huang, Pei-Shen; Lee, Si-Chen

    2016-01-01

    Paclitaxel is used as an adjuvant to enhance the effectiveness of ionization radiation therapy; however, high-energy radiation often damages the healthy cells surrounding cancer cells. Low-energy, middle-infrared radiation (MIR) has been shown to prevent tissue damage, and recent studies have begun combining MIR with paclitaxel. However, the cytotoxic effects of this treatment combination remain unclear, and the mechanism underlying its effects on HeLa cells has yet to be elucidated. This study investigated the effectiveness of treating HeLa human cervical cancer cells with a combination of paclitaxel for 48 h in conjunction with narrow-band MIR from 3.0 to 5.0 μm. This combined treatment significantly inhibited the growth of HeLa cells. Specifically, results from Annexin V-FITC/PI apoptosis detection and cell mitochondrial membrane potential analyses revealed an increase in apoptotic cell death and a collapse of mitochondrial membrane potential. One possible mechanism underlying cellular apoptosis is an increase in oxidative stress. These preliminary findings provide evidence to support the combination of narrow-band MIR with paclitaxel as an alternative approach in the treatment of human cervical cancer.

  3. Lateralization of narrow-band noise by blind and sighted listeners.

    Simon, Helen J; Divenyi, Pierre L; Lotze, Al

    2002-01-01

    The effects of varying interaural time delay (ITD) and interaural intensity difference (IID) were measured in normal-hearing sighted and congenitally blind subjects as a function of eleven frequencies and at sound pressure levels of 70 and 90 dB, and at a sensation level of 25 dB (sensation level refers to the pressure level of the sound above its threshold for the individual subject). Using an 'acoustic' pointing paradigm, the subject varied the IID of a 500 Hz narrow-band (100 Hz) noise (the 'pointer') to coincide with the apparent lateral position of a 'target' ITD stimulus. ITDs of 0, +/-200, and +/-400 micros were obtained through total waveform delays of narrow-band noise, including envelope and fine structure. For both groups, the results of this experiment confirm the traditional view of binaural hearing for like stimuli: non-zero ITDs produce little perceived lateral displacement away from 0 IID at frequencies above 1250 Hz. To the extent that greater magnitude of lateralization for a given ITD, presentation level, and center frequency can be equated with superior localization abilities, blind listeners appear at least comparable and even somewhat better than sighted subjects, especially when attending to signals in the periphery. The present findings suggest that blind listeners are fully able to utilize the cues for spatial hearing, and that vision is not a mandatory prerequisite for the calibration of human spatial hearing.

  4. Can optical diagnosis of small colon polyps be accurate? Comparing standard scope without narrow banding to high definition scope with narrow banding.

    Ashktorab, Hassan; Etaati, Firoozeh; Rezaeean, Farahnaz; Nouraie, Mehdi; Paydar, Mansour; Namin, Hassan Hassanzadeh; Sanderson, Andrew; Begum, Rehana; Alkhalloufi, Kawtar; Brim, Hassan; Laiyemo, Adeyinka O

    2016-07-28

    To study the accuracy of using high definition (HD) scope with narrow band imaging (NBI) vs standard white light colonoscope without NBI (ST), to predict the histology of the colon polyps, particularly those high definition colonoscopes with NBI. The histopathologic diagnosis was reported by pathologists as part of routine care. Of participants in the study, 55 (37%) were male and median (interquartile range) of age was 56 (19-80). Demographic, clinical characteristics, past medical history of patients, and the data obtained by two instruments were not significantly different and two methods detected similar number of polyps. In ST scope 89% of polyps were scope (P = 0.7). The ST scope had a positive predictive value (PPV) and positive likelihood ratio (PLR) of 86% and 4.0 for adenoma compared to 74% and 2.6 for HD scope. There was a trend of higher sensitivity for HD scope (68%) compare to ST scope (53%) with almost the same specificity. The ST scope had a PPV and PLR of 38% and 1.8 for hyperplastic polyp (HPP) compared to 42% and 2.2 for HD scope. The sensitivity and specificity of two instruments for HPP diagnosis were similar. Our results indicated that HD scope was more sensitive in diagnosis of adenoma than ST scope. Clinical diagnosis of HPP with either scope is less accurate compared to adenoma. Colonoscopy diagnosis is not yet fully matched with pathologic diagnosis of colon polyp. However with the advancement of both imaging and training, it may be possible to increase the sensitivity and specificity of the scopes and hence save money for eliminating time and the cost of Immunohistochemistry/pathology.

  5. Effect of combination of fractional CO2 laser and narrow-band ultraviolet B versus narrow-band ultraviolet B in the treatment of non-segmental vitiligo.

    El-Zawahry, Mohamed Bakr; Zaki, Naglaa Sameh; Wissa, Marian Youssry; Saleh, Marwah Adly

    2017-12-01

    The present study was designed to evaluate the effect of combining fractional CO 2 laser with narrow-band ultraviolet B (NB-UVB) versus NB-UVB in the treatment of non-segmental vitiligo. The study included 20 patients with non-segmental stable vitiligo. They were divided into two groups. Group I received a single session of fractional CO 2 laser therapy on the right side of the body followed by NB-UVB phototherapy twice per week for 8 weeks. Group II received a second session of fractional CO 2 laser therapy after 4 weeks from starting treatment with NB-UVB. The vitiligo lesions were assessed before treatment and after 8 weeks of treatment by VASI. At the end of the study period, the vitiligo area score index (VASI) in group I decreased insignificantly on both the right (-2.6%) and left (-16.4%) sides. In group II, VASI increased insignificantly on the right (+14.4%) and left (+2.5%) sides. Using Adobe Photoshop CS6 extended program to measure the area of vitiligo lesions, group I showed a decrease of -1.02 and -6.12% in the mean area percentage change of vitiligo lesions on the right and left sides, respectively. In group II the change was +9.84 and +9.13% on the right and left sides, respectively. In conclusion, combining fractional CO 2 laser with NB-UVB for the treatment of non-segmental vitiligo did not show any significant advantage over treatment with NB-UVB alone. Further study of this combination for longer durations in the treatment of vitiligo is recommended.

  6. Narrow band flame emission from dieseline and diesel spray combustion in a constant volume combustion chamber

    Wu, Zengyang

    2016-08-18

    In this paper, spray combustion of diesel (No. 2) and diesel-gasoline blend (dieseline: 80% diesel and 20% gasoline by volume) were investigated in an optically accessible constant volume combustion chamber. Effects of ambient conditions on flame emissions were studied. Ambient oxygen concentration was varied from 12% to 21% and three ambient temperatures were selected: 800 K, 1000 K and 1200 K. An intensified CCD camera coupled with bandpass filters was employed to capture the quasi-steady state flame emissions at 430 nm and 470 nm bands. Under non-sooting conditions, the narrow-band flame emissions at 430 nm and 470 nm can be used as indicators of CH∗ (methylidyne) and HCHO∗ (formaldehyde), respectively. The lift-off length was measured by imaging the OH∗ chemiluminescence at 310 nm. Flame emission structure and intensity distribution were compared between dieseline and diesel at wavelength bands. Flame emission images show that both narrow band emissions become shorter, thinner and stronger with higher oxygen concentration and higher ambient temperature for both fuels. Areas of weak intensity are observed at the flame periphery and the upstream for both fuels under all ambient conditions. Average flame emission intensity and area were calculated for 430 nm and 470 nm narrow-band emissions. At a lower ambient temperature the average intensity increases with increasing ambient oxygen concentration. However, at the 1200 K ambient temperature condition, the average intensity is not increasing monotonically for both fuels. For most of the conditions, diesel has a stronger average flame emission intensity than dieseline for the 430 nm band, and similar phenomena can be observed for the 470 nm band with 800 K and 1200 K ambient temperatures. However, for the 1000 K ambient temperature cases, dieseline has stronger average flame emission intensities than diesel for all oxygen concentrations at 470 nm band. Flame emissions for the two bands have a

  7. Laser-based ultrasonics by dual-probe interferometer detection and narrow-band ultrasound generation

    Huang, Jin

    1993-01-01

    Despite the advantages of laser-based ultrasonic (LBU) systems, the overall sensitivity of LBU systems needs to be improved for practical applications. Progress is reported to achieve better LBU detection accuracy and sensitivity for applications with surface waves and Lamb waves. A novel dual-probe laser interferometer has been developed to measure the same signal at two points. The dual-probe interferometer is a modification of a conventional single-probe interferometer in that the reference beam is guided to a second detecting point on the specimen surface to form a differential measurement mode, which measure the difference of the displacements at the two points. This dual-probe interferometer is particularly useful for accurate measurements of the speed and attenuation of surface waves and Lamb waves. The dual-probe interferometer has been applied to obtain accurate measurements of the surface wave speed and attenuation on surfaces of increasing surface roughness. It has also been demonstrated that with an appropriate signal processing method, namely, the power cepstrum method, the dual-probe interferometer is applicable to measure the local surface wave speed even when the probe separation is so small that the two waveforms in the interferometer output signal overlap in the time domain. Narrow-band signal generation and detection improve the sensitivity of LBU systems. It is proposed to use a diffraction grating to form an array of illuminating strips which form a source of narrowband surface and Lamb waves. The line-array of thermoelastic sources generates narrow-band signals whose frequency and bandwidth can be easily controlled. The optimum line-array parameters, such as width, spacing and the number of lines in the array have been derived theoretically and verified experimentally. Narrow-band signal generation with optimum parameters has been demonstrated. The enhanced LBU system with dual-probe detection and narrowband signal generation has been

  8. Analysis of the outlook for using narrow-band spontaneous emission sources for atmospheric air purification

    Boyarchuk, K A; Karelin, A V; Shirokov, R V

    2003-01-01

    The outlook for using narrow-band spontaneous emission sources for purification of smoke gases from sulphur and nitrogen oxides is demonstrated by calculations based on a nonstationary kinetic model of the N 2 - O 2 - H 2 O - CO 2 - SO 2 mixture. The dependences of the mixture purification efficiency on the UV source power at different wavelengths, the exposure time, and the mixture temperature are calculated. It is shown that the radiation sources proposed in the paper will provide better purification of waste gases in the atmosphere. The most promising is a KrCl* lamp emitting an average power of no less than 100 W at 222 nm. (laser applications and other topics in quantum electronics)

  9. H-tailored surface conductivity in narrow band gap In(AsN)

    Velichko, A. V., E-mail: amalia.patane@nottingham.ac.uk, E-mail: anton.velychko@nottingham.ac.uk; Patanè, A., E-mail: amalia.patane@nottingham.ac.uk, E-mail: anton.velychko@nottingham.ac.uk; Makarovsky, O. [School of Physics and Astronomy, The University of Nottingham, Nottingham NG7 2RD (United Kingdom); Capizzi, M.; Polimeni, A. [Dipartimento di Fisica, Sapienza Università di Roma, Piazzale A. Moro 2, 00185 Roma (Italy); Sandall, I. C.; Tan, C. H. [Department of Electronic and Electrical Engineering, The University of Sheffield, Sheffield S1 3JD (United Kingdom); Giubertoni, D. [Center for Materials and Microsystems—Fondazione Bruno Kessler, via Sommarive 18, 38123 Povo, Trento (Italy); Krier, A.; Zhuang, Q. [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom)

    2015-01-12

    We show that the n-type conductivity of the narrow band gap In(AsN) alloy can be increased within a thin (∼100 nm) channel below the surface by the controlled incorporation of H-atoms. This channel has a large electron sheet density of ∼10{sup 18 }m{sup −2} and a high electron mobility (μ > 0.1 m{sup 2}V{sup −1}s{sup −1} at low and room temperature). For a fixed dose of impinging H-atoms, its width decreases with the increase in concentration of N-atoms that act as H-traps thus forming N-H donor complexes near the surface.

  10. Mitigation of Unwanted Forward Narrow-band Radiation from PCBs with a Metamaterial Unit Cell

    Ruaro, Andrea; Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2013-01-01

    Mitigation of EMI from a PCB is obtained through the use of a metamaterial unit cell. The focus is on the reduction of narrow-band radiation in the forward hemisphere when the resonant element is etched on a layer located between the source of radiation and the ground plane. As opposed to previous...... publications in the literature, the aim of this work is the application of a filter to scattered radiation, generalizing the former characterizations based solely upon transmission lines’ insertion loss. The radiating area accounts for traces and components placed on the top layer of a PCB and is simulated via...... a patch antenna. The study exhibits how the radiation pattern and the electric field on the patch antenna change within and outside the resonance bandwidth of the parasitic element. An EMC assessment provides experimental verification of the operating principle....

  11. 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

  12. High thermal stability solution-processable narrow-band gap molecular semiconductors.

    Liu, Xiaofeng; Hsu, Ben B Y; Sun, Yanming; Mai, Cheng-Kang; Heeger, Alan J; Bazan, Guillermo C

    2014-11-19

    A series of narrow-band gap conjugated molecules with specific fluorine substitution patterns has been synthesized in order to study the effect of fluorination on bulk thermal stability. As the number of fluorine substituents on the backbone increase, one finds more thermally robust bulk structures both under inert and ambient conditions as well as an increase in phase transition temperatures in the solid state. When integrated into field-effect transistor devices, the molecule with the highest degree of fluorination shows a hole mobility of 0.15 cm(2)/V·s and a device thermal stability of >300 °C. Generally, the enhancement in thermal robustness of bulk organization and device performance correlates with the level of C-H for C-F substitution. These findings are relevant for the design of molecular semiconductors that can be introduced into optoelectronic devices to be operated under a wide range of conditions.

  13. A Compact Narrow-Band Bandstop Filter Using Spiral-Shaped Defected Microstrip Structure

    J. Wang

    2014-04-01

    Full Text Available A novel compact narrow-band bandstop filter is implemented by using the proposed spiral-shaped defected microstrip structure (SDMS in this paper. Compared with other DMSs, the presented SDMS exhibits the advantage of compact size and narrow stopband. Meanwhile, an approximate design rule of the SDMS is achieved and the effects of the dimensions on the resonant frequency and 3 dB fractional bandwidth (FBW are analyzed in detail. Both the simulation and measurement results of the fabricated bandstop filter show that it has a 10 dB stopband from 3.4 GHz to 3.6 GHz with more than 45 dB rejection at the center frequency.

  14. Narrow band wavelength selective filter using grating assisted single ring resonator

    Prabhathan, P., E-mail: PPrabhathan@ntu.edu.sg; Murukeshan, V. M. [Centre for Optical and Laser Engineering (COLE), School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2014-09-15

    This paper illustrates a filter configuration which uses a single ring resonator of larger radius connected to a grating resonator at its drop port to achieve single wavelength selectivity and switching property with spectral features suitable for on-chip wavelength selection applications. The proposed configuration is expected to find applications in silicon photonics devices such as, on-chip external cavity lasers and multi analytic label-free biosensors. The grating resonator has been designed for a high Q-factor, high transmittivity, and minimum loss so that the wavelength selectivity of the device is improved. The proof-of-concept device has been demonstrated on a Silicon-on-Insulator (SOI) platform through electron beam lithography and Reactive Ion Etching (RIE) process. The transmission spectrum shows narrow band single wavelength selection and switching property with a high Free Spectral Range (FSR) ∼60 nm and side band rejection ratio >15 dB.

  15. 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.

  16. Ultrabright narrow-band telecom two-photon source for long-distance quantum communication

    Niizeki, Kazuya; Ikeda, Kohei; Zheng, Mingyang; Xie, Xiuping; Okamura, Kotaro; Takei, Nobuyuki; Namekata, Naoto; Inoue, Shuichiro; Kosaka, Hideo; Horikiri, Tomoyuki

    2018-04-01

    We demonstrate an ultrabright narrow-band two-photon source at the 1.5 µm telecom wavelength for long-distance quantum communication. By utilizing a bow-tie cavity, we obtain a cavity enhancement factor of 4.06 × 104. Our measurement of the second-order correlation function G (2)(τ) reveals that the linewidth of 2.4 MHz has been hitherto unachieved in the 1.5 µm telecom band. This two-photon source is useful for obtaining a high absorption probability close to unity by quantum memories set inside quantum repeater nodes. Furthermore, to the best of our knowledge, the observed spectral brightness of 3.94 × 105 pairs/(s·MHz·mW) is also the highest reported over all wavelengths.

  17. Phototherapy UVB narrow band treatment of psoriasis, mycosis fungoides and vitiligo

    Reyes, M.V.; Kutnizky, R.; Bosch, M.P.; Ruiz Lascano, A.

    2013-01-01

    Introduction: Numerous studies have shown the beneficial effect of ultraviolet radiation for the treatment of lymphoproliferative or inflammatory skin diseases. Objective: To determine the response to UVB narrow band (UVB-nb) in psoriasis, mycosis fungoides stage IA, IB and vitiligo, in the Dermatology Department of Hospital Privado from May 2009 to January 2011. To correlate total energy dose used and the total number of sessions with the response achieved in each disease. To describe adverse reactions; determine demographic characteristics of the population and comorbidities in psoriasis and vitiligo. Material and Methods: We performed a prospective, descriptive, analytical, observational study. We included all patients assessed for initiation of UVB-nb. Regarding the patients who did not start or interrupted the treatment a survey was conducted to assess the causes. We calculated the cumulative dose and number of sessions at the end of treatment. (authors) [es

  18. On a business cycle model with fractional derivative under narrow-band random excitation

    Lin, Zifei; Li, Jiaorui; Li, Shuang

    2016-01-01

    This paper analyzes the dynamics of a business cycle model with fractional derivative of order  α (0 < α < 1) subject to narrow-band random excitation, in which fractional derivative describes the memory property of the economic variables. Stochastic dynamical system concepts are integrated into the business cycle model for understanding the economic fluctuation. Firstly, the method of multiple scales is applied to derive the model to obtain the approximate analytical solution. Secondly, the effect of economic policy with fractional derivative on the amplitude of the economic fluctuation and the effect on stationary probability density are studied. The results show macroeconomic regulation and control can lower the stable amplitude of economic fluctuation. While in the process of equilibrium state, the amplitude is magnified. Also, the macroeconomic regulation and control improves the stability of the equilibrium state. Thirdly, how externally stochastic perturbation affects the dynamics of the economy system is investigated.

  19. 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)

  20. [Nursing care management in dermatological patient on phototherapy narrow band UVB].

    de Argila Fernández-Durán, Nuria; Blasco Maldonado, Celeste; Martín Gómez, Mónica

    2013-01-01

    Phototherapy with narrow band ultraviolet B is a treatment used in some dermatology units, and is the first choice in some dermatological diseases due to being comfortable and cheap. The aim of this paper is to describe the management and nursing care by grouping more specific diagnoses, following NANDA-NIC/NOC taxonomy, such as the methodology from application, technique, material, and personnel to space-related aspects, with the aim of avoiding the clinical variability and the possible associated risks for the patients, and for the nurses who administer the treatment. The continuity of the same nurse in the follow-up sessions stimulates the relationship between medical personnel and patients, key points for loyalty and therapeutic adherence. This paper examines a consensus procedure with the Dermatology Unit Team and accredited by the Hospital Quality Unit. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  1. A narrow-band k-distribution model with single mixture gas assumption for radiative flows

    Jo, Sung Min; Kim, Jae Won; Kwon, Oh Joon

    2018-06-01

    In the present study, the narrow-band k-distribution (NBK) model parameters for mixtures of H2O, CO2, and CO are proposed by utilizing the line-by-line (LBL) calculations with a single mixture gas assumption. For the application of the NBK model to radiative flows, a radiative transfer equation (RTE) solver based on a finite-volume method on unstructured meshes was developed. The NBK model and the RTE solver were verified by solving two benchmark problems including the spectral radiance distribution emitted from one-dimensional slabs and the radiative heat transfer in a truncated conical enclosure. It was shown that the results are accurate and physically reliable by comparing with available data. To examine the applicability of the methods to realistic multi-dimensional problems in non-isothermal and non-homogeneous conditions, radiation in an axisymmetric combustion chamber was analyzed, and then the infrared signature emitted from an aircraft exhaust plume was predicted. For modeling the plume flow involving radiative cooling, a flow-radiation coupled procedure was devised in a loosely coupled manner by adopting a Navier-Stokes flow solver based on unstructured meshes. It was shown that the predicted radiative cooling for the combustion chamber is physically more accurate than other predictions, and is as accurate as that by the LBL calculations. It was found that the infrared signature of aircraft exhaust plume can also be obtained accurately, equivalent to the LBL calculations, by using the present narrow-band approach with a much improved numerical efficiency.

  2. Two cases of eczematid-like purpura of Doucas and Kapetanakis responsive to narrow band ultraviolet B treatment.

    Karadag, Ayse Serap; Bilgili, Serap Gunes; Onder, Sevda; Calka, Omer

    2013-04-01

    Eczematid-like purpura of Doucas and Kapetanakis is a type of pigmented purpuric dermatoses (PPDs) with eczematous changes in the purpuric surface. A 10-year-old male and a 44-year-old male patients were admitted to our clinics for itching and flaking of the skin rashes. Based on the clinical and histopathological evaluations, the rashes were identified as eczematid-like PPDs of Doucas and Kapetanakis. Both patients were treated with narrow band ultraviolet B. The lesions were remarkably regressed following the treatment. These cases reported due its rarity and good response to narrow band ultraviolet B. © 2013 John Wiley & Sons A/S.

  3. 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

  4. Efektivitas Terapi Kortikosteroid Intranasal pada Hipertrofi Adenoid Usia Dewasa berdasarkan Pemeriksaan Narrow Band Imaging

    Sinta Sari Ratunanda

    2016-12-01

    Full Text Available Adenoid hypertrophy is a process in which adenoid size becomes enlarged and causes clinical symptoms, especially nasal obstruction. Adenoid hypertrophy can be due to physiological, inflammatory, or malignancy processes. Adenoid inflammatory process can be assessed using a flexible fiberoptic nasoendoscopy with narrow band imaging (NBI. Intranasal corticosteroid is one of the choices to treat adenoid hypertrophy in children; however, more experiments are needed to use it in adults. This study was performed in the period of November 2012 to January 2013 at the outpatient clinic of the Otorhinolaryngology-Head and Neck Surgery Department of Dr. Hasan Sadikin General Hospital Bandung, using pre- and post-test open-labeled quasiexperimental design. Sample was selected through consecutive sampling, involving 11 subjects. Diagnosis was based on research subject’s anamnesis, ear nose and throat (ENT physical examination, NBI-equipped fiberoptic nasoendocopy examination, and adenoid mucosal biopsy. Subjects were given intranasal corticosteroid therapy for four weeks. NBI-equipped fiberoptic nasoendocopy examination and biopsy examination were performed after therapy. Data were analyzed using Wilcoxon test, showing significant improvement of the adenoid inflammation after intranasal corticosteroids therapy (p<0.05. McNemar test results showed a significant reduction in adenoid size (p<0.05. Spearman rank test showed a significant correlation between histopathologic findings and NBI examination result (p<0.05. In conclusion, intranasal corticosteroids are effective for adult adenoid hypertrophy treatment based on NBI examination. [MKB. 2016;48(4:228–33

  5. Band Edge Dynamics and Multiexciton Generation in Narrow Band Gap HgTe Nanocrystals.

    Livache, Clément; Goubet, Nicolas; Martinez, Bertille; Jagtap, Amardeep; Qu, Junling; Ithurria, Sandrine; Silly, Mathieu G; Dubertret, Benoit; Lhuillier, Emmanuel

    2018-04-11

    Mercury chalcogenide nanocrystals and especially HgTe appear as an interesting platform for the design of low cost mid-infrared (mid-IR) detectors. Nevertheless, their electronic structure and transport properties remain poorly understood, and some critical aspects such as the carrier relaxation dynamics at the band edge have been pushed under the rug. Some of the previous reports on dynamics are setup-limited, and all of them have been obtained using photon energy far above the band edge. These observations raise two main questions: (i) what are the carrier dynamics at the band edge and (ii) should we expect some additional effect (multiexciton generation (MEG)) as such narrow band gap materials are excited far above the band edge? To answer these questions, we developed a high-bandwidth setup that allows us to understand and compare the carrier dynamics resonantly pumped at the band edge in the mid-IR and far above the band edge. We demonstrate that fast (>50 MHz) photoresponse can be obtained even in the mid-IR and that MEG is occurring in HgTe nanocrystal arrays with a threshold around 3 times the band edge energy. Furthermore, the photoresponse can be effectively tuned in magnitude and sign using a phototransistor configuration.

  6. Narrow Band Imaging Enhances the Detection Rate of Penetration and Aspiration in FEES.

    Nienstedt, Julie C; Müller, Frank; Nießen, Almut; Fleischer, Susanne; Koseki, Jana-Christiane; Flügel, Till; Pflug, Christina

    2017-06-01

    Narrow band imaging (NBI) is widely used in gastrointestinal, laryngeal, and urological endoscopy. Its original purpose was to visualize vessels and epithelial irregularities. Based on our observation that adding NBI to common white light (WL) improves the contrast of the test bolus in fiberoptic endoscopic evaluation of swallowing (FEES), we now investigated the potential value of NBI in swallowing disorders. 148 FEES images were analyzed from 74 consecutive patients with swallowing disorders, including 74 with and 74 without NBI. All images were evaluated by four dysphagia specialists. Findings were classified according to Rosenbek's penetration-aspiration scale modified for evaluating these FEES images. Intra- and inter-rater reliability was determined as well as observer confidence. A better visualization of the bolus is the main advantage of NBI in FEES. This generally leads to sharper optical contrasts and better detection of small bolus quantities. Accordingly, NBI enhances the detection rate of penetration and aspiration. On average, identification of laryngeal penetration increased from 40 to 73% and of aspiration from 13 to 24% (each p dysphagia evaluation and shortening FEES evaluation time. It leads to a markedly higher detection rate of pathological findings. The significantly better intra- and inter-rater reliability argues further for a better overall reproducibly of FEES interpretation.

  7. Use of narrow-band imaging bronchoscopy in detection of lung cancer.

    Zaric, Bojan; Perin, Branislav

    2010-05-01

    Narrow-band imaging (NBI) is a new endoscopic technique designed for detection of pathologically altered submucosal and mucosal microvascular patterns. The combination of magnification videobronchoscopy and NBI showed great potential in the detection of precancerous and cancerous lesions of the bronchial mucosa. The preliminary studies confirmed supremacy of NBI over white-light videobronchoscopy in the detection of premalignant and malignant lesions. Pathological patterns of capillaries in bronchial mucosa are known as Shibuya's descriptors (dotted, tortuous and abrupt-ending blood vessels). Where respiratory endoscopy is concerned, the NBI is still a 'technology in search of proper indication'. More randomized trials are necessary to confirm the place of NBI in the diagnostic algorithm, and more trials are needed to evaluate the relation of NBI to autofluorescence videobronchoscopy and to white-light magnification videobronchoscopy. Considering the fact that NBI examination of the tracheo-bronchial tree is easy, reproducible and clear to interpret, it is certain that NBI videobronchoscopy will play a significant role in the future of lung cancer detection and staging.

  8. Narrow-band modulation of semiconductor lasers at millimeter wave frequencies (7100 GHz) by mode locking

    Lau, K.Y.

    1990-01-01

    This paper reports on the possibility of mode locking a semiconductor laser at millimeter wave frequencies approaching and beyond 100 GHz which was investigated theoretically and experimentally. It is found that there are no fundamental theoretical limitations in mode locking at frequencies below 100 GHz. AT these high frequencies, only a few modes are locked and the output usually takes the form of a deep sinusoidal modulation which is synchronized in phase with the externally applied modulation at the intermodal heat frequency. This can be regarded for practical purposes as a highly efficient means of directly modulating an optical carrier over a narrow band at millimeter wave frequencies. Both active and passive mode locking are theoretically possible. Experimentally, predictions on active mode locking have been verified in prior publications up to 40 GHz. For passive mode locking, evidence consistent with passive mode locking was observed in an inhomogeneously pumped GaAIAs laser at a frequency of approximately 70 GHz. A large differential gain-absorption ratio such as that present in an inhomogeneously pumped single quantum well laser is necessary for pushing the passive mode-locking frequency beyond 100 GHz

  9. Development of narrow-band fluorescence index for the detection of aflatoxin contaminated corn

    Yao, Haibo; Hruska, Zuzana; Kincaid, Russell; Ononye, Ambrose; Brown, Robert L.; Bhatnagar, Deepak; Cleveland, Thomas E.

    2011-06-01

    Aflatoxin is produced by the fungus Aspergillus flavus when the fungus invades developing corn kernels. Because of its potent toxicity, the levels of aflatoxin are regulated by the Food and Drug Administration (FDA) in the US, allowing 20 ppb (parts per billion) limits in food, and feed intended for interstate commerce. Currently, aflatoxin detection and quantification methods are based on analytical tests. These tests require the destruction of samples, can be costly and time consuming, and often rely on less than desirable sampling techniques. Thus, the ability to detect aflatoxin in a rapid, non-invasive way is crucial to the corn industry in particular. This paper described how narrow-band fluorescence indices were developed for aflatoxin contamination detection based on single corn kernel samples. The indices were based on two bands extracted from full wavelength fluorescence hyperspectral imagery. The two band results were later applied to two large sample experiments with 25 g and 1 kg of corn per sample. The detection accuracies were 85% and 95% when 100 ppb threshold was used. Since the data acquisition period is significantly lower for several image bands than for full wavelength hyperspectral data, this study would be helpful in the development of real-time detection instrumentation for the corn industry.

  10. "Leopard skin sign": the use of narrow-band imaging with magnification endoscopy in celiac disease.

    Tchekmedyian, Asadur J; Coronel, Emmanuel; Czul, Frank

    2014-01-01

    Celiac Disease (CD) is an immune reaction to gluten containing foods such as rye, wheat and barley. This condition affects individuals with a genetic predisposition; it targets the small bowel and may cause symptoms including diarrhea, malabsorption, weight loss, abdominal pain and bloating. The diagnosis is made by serologic testing of celiac-specific antibodies and confirmed by histology. Certain endoscopic characteristics, such as scalloping, reduction in the number of folds, mosaic-pattern mucosa or nodular mucosa, are suggestive of CD and can be visualized under white light endoscopy. Due to its low sensitivity, endoscopy alone is not recommended to diagnose CD; however, enhanced visual identification of suspected mucosal abnormalities through the use of new technologies, such as narrow band imaging with magnification (NBI-ME), could assist in targeting biopsies and thereby increasing the sensitivity of endoscopy. This is a case series of seven patients with serologic and histologic diagnoses of CD who underwent upper endoscopies with NBI-ME imaging technology as part of their CD evaluation. By employing this imaging technology, we could identify patchy atrophy sites in a mosaic pattern, with flattened villi and alteration of the central capillaries of the duodenal mucosa. We refer to this epithelial pattern as "Leopard Skin Sign". Since epithelial lesions are easily seen using NBI-ME, we found it beneficial for identifying and targeting biopsy sites. Larger prospective studies are warranted to confirm our findings.

  11. Polyp Detection, Characterization, and Management Using Narrow-Band Imaging with/without Magnification

    Takahiro Utsumi

    2015-11-01

    Full Text Available Narrow-band imaging (NBI is a new imaging technology that was developed in 2006 and has since spread worldwide. Because of its convenience, NBI has been replacing the role of chromoendoscopy. Here we review the efficacy of NBI with/without magnification for detection, characterization, and management of colorectal polyps, and future perspectives for the technology, including education. Recent studies have shown that the next-generation NBI system can detect significantly more colonic polyps than white light imaging, suggesting that NBI may become the modality of choice from the beginning of screening. The capillary pattern revealed by NBI, and the NBI International Colorectal Endoscopic classification are helpful for prediction of histology and for estimating the depth of invasion of colorectal cancer. However, NBI with magnifying colonoscopy is not superior to magnifying chromoendoscopy for estimation of invasion depth. Currently, therefore, chromoendoscopy should also be performed additionally if deep submucosal invasive cancer is suspected. If endoscopists become able to accurately estimate colorectal polyp pathology using NBI, this will allow adenomatous polyps to be resected and discarded; thus, reducing both the risk of polypectomy and costs. In order to achieve this goal, a suitable system for education and training in in vivo diagnostics will be necessary.

  12. A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

    Kasparek, W.; Petelin, M. I.; Shchegolkov, D. Yu; Erckmann, V.; Plaum, B.; Bruschi, A.; ECRH Groups at IPP Greifswald; Karlsruhe, FZK; Stuttgart, IPF

    2008-05-01

    A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTMs). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane/upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of megahertz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Low-power measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented.

  13. A fast switch, combiner and narrow-band filter for high-power millimetre wave beams

    Kasparek, W.; Plaum, B.; Petelin, M.I.; Shchegolkov, D.Yu; Erckmann, V.; Bruschi, A.

    2008-01-01

    A fast directional switch (FADIS) is described, which allows controlled switching of high-power microwaves between two outputs. A possible application could be synchronous stabilization of neoclassical tearing modes (NTMs). Generally, the device can be used to share the installed EC power between different types of launchers or different applications (e.g. in ITER, midplane/upper launcher). The switching is performed electronically without moving parts by a small frequency-shift keying of the gyrotron (some tens of megahertz), and a narrow-band diplexer. The device can be operated as a beam combiner also, which offers attractive transmission perspectives in multi-megawatt ECRH systems. In addition, these diplexers are useful for plasma diagnostic systems employing high-power sources due to their filter characteristics. The principle and the design of a four-port quasi-optical resonator diplexer is presented. Low-power measurements of switching contrast, mode purity and efficiency show good agreement with theory. Preliminary frequency modulation characteristics of gyrotrons are shown, and first results from high-power switching experiments using the ECRH system for W7-X are presented

  14. A multicenter validation of an endoscopic classification with narrow band imaging for gastric precancerous and cancerous lesions

    Pimentel-Nunes, P.; Dinis-Ribeiro, M.; Soares, J. B.; Marcos-Pinto, R.; Santos, C.; Rolanda, C.; Bastos, R. P.; Areia, M.; Afonso, L.; Bergman, J.; Sharma, P.; Gotoda, T.; Henrique, R.; Moreira-Dias, L.

    2012-01-01

    Background and study aim: The reliability and external validity of narrow band imaging (NBI) in the stomach have not been described consistently. The aim of the current study was to describe and estimate the accuracy and reliability of a simplified classification system for NBI in the diagnosis of

  15. Increased polyp detection using narrow band imaging compared with high resolution endoscopy in patients with hyperplastic polyposis syndrome

    Boparai, K. S.; van den Broek, F. J. C.; van Eeden, S.; Fockens, P.; Dekker, E.

    2011-01-01

    Hyperplastic polyposis syndrome (HPS) is associated with colorectal cancer and is characterized by multiple hyperplastic polyps, sessile serrated adenomas (SSAs) and adenomas. Narrow band imaging (NBI) may improve the detection of polyps in HPS. We aimed to compare polyp miss rates with NBI with

  16. High-resolution endoscopy plus chromoendoscopy or narrow-band imaging in Barrett's esophagus: a prospective randomized crossover study

    Kara, M. A.; Peters, F. P.; Rosmolen, W. D.; Krishnadath, K. K.; ten Kate, F. J.; Fockens, P.; Bergman, J. J. G. H.

    2005-01-01

    Background and study aims: High-resolution endoscopy (HRE) may improve the detection of early neoplasia in Barrett's esophagus. Indigo carmine chromoendoscopy (ICc) and narrow-band imaging (NBI) may be useful techniques to complement HRE. The aim of this study was to compare HRE-ICC with HrE-NBI for

  17. Head and hand detuning effect study of narrow-band against wide-band mobile phone antennas

    Bahramzy, Pevand; Pedersen, Gert Frølund

    2014-01-01

    Wide-band (WB) and narrow-band (NB) antennas in terms of performance are compared, when interacting with the user’s right head and hand (RHH). The investigations are done through experimental measurements, using standardised head phantom and hand. It is shown that WB antennas detune more than NB ...

  18. A test of ν stability using a 200 GeV narrow-band neutrino beam at BEBC

    Deden, H.; Grässler, H.; Kirch, D.; Schultze, K.; Böckmann, K.; Glimpf, W.; Kokott, T. P.; Nellen, B.; Saarikko, H.; Wünsch, B.; Bosetti, P. C.; Cundy, D. C.; Grant, A. L.; Hulth, P. O.; Pape, L.; Peyrou, Ch.; Skjeggestad, O.; Wachsmuth, H.; Mermikides, M.; Vayaki, A.; Barnham, K. W. J.; Butterworth, I.; Chima, J. S.; Clayton, E. F.; Miller, D. B.; Mobayyen, M.; Petrides, A.; Powell, K. J.; Albajar, C.; Lloyd, J. L.; Myatt, G.; Perkins, D. H.; Poppe, M.; Radojicic, D.; Renton, P.; Saitta, B.; Wells, J.; Bloch, M.; Bolognese, T.; Tallini, B.; Velasco, J.; Vignaud, D.; Aachen-Bonn-CERN-Demokritos Athens-I. C. London-Oxford-Saclay Collaboration

    1981-01-01

    νe induced events obtained in a 200 GeV narrow-band beam have been studied and compared to the number expected from K e3+ decay. Agreement is found between the expected and observed numbers allowing limits to be set on νe → νx mixing.

  19. Synchrotron Studies of Narrow Band and Low-Dimensional Materials. Final Report for July 1, 1990 --- December 31, 2002

    Allen, J. W.

    2003-01-01

    This report summarizes a 12-year program of various kinds of synchrotron spectroscopies directed at the electronic structures of narrow band and low-dimensional materials that display correlated electron behaviors such as metal-insulator transitions, mixed valence, superconductivity, Kondo moment quenching, heavy Fermions, and non-Fermi liquid properties

  20. Therapeutic efficacy of narrow band imaging-assisted transurethral electrocoagulation for ulcer-type interstitial cystitis/painful bladder syndrome.

    Kajiwara, Mitsuru; Inoue, Shougo; Kobayashi, Kanao; Ohara, Shinya; Teishima, Jun; Matsubara, Akio

    2014-04-01

    Narrow band imaging cystoscopy can increase the visualization and detection of Hunner's lesions. A single-center, prospective clinical trial was carried out aiming to show the effectiveness of narrow band imaging-assisted transurethral electrocoagulation for ulcer-type interstitial cystitis/painful bladder syndrome. A total of 23 patients (19 women and 4 men) diagnosed as having ulcer-type interstitial cystitis/painful bladder syndrome were included. All typical Hunner's lesions and suspected areas identified by narrow band imaging were electrocoagulated endoscopically after the biopsy of those lesions. Therapeutic efficacy was assessed prospectively by using visual analog scale score of pain, O'Leary-Sant's symptom index, O'Leary-Sant's problem index and overactive bladder symptom score. The mean follow-up period was 22 months. All patients (100%) experienced a substantial improvement in pain. The average visual analog scale pain scores significantly decreased from 7.3 preoperatively to 1.2 1 month postoperatively. A total of 21 patients (91.3%) who reported improvement had at least a 50% reduction in bladder pain, and five reported complete resolution. Daytime frequency was significantly decreased postoperatively. O'Leary-Sant's symptom index, O'Leary-Sant's problem index and overactive bladder symptom score were significantly decreased postoperatively. However, during the follow-up period, a total of six patients had recurrence, and repeat narrow band imaging-assisted transurethral electrocoagulation of the recurrent lesions was carried out for five of the six patients, with good response in relieving bladder pain. Our results showed that narrow band imaging-assisted transurethral electrocoagulation could be a valuable therapeutic alternative in patients with ulcer-type interstitial cystitis/painful bladder syndrome, with good efficacy and reduction of recurrence rate. © 2014 The Japanese Urological Association.

  1. Detection of Mucosal Recurrent Nasopharyngeal Carcinomas After Radiotherapy With Narrow-Band Imaging Endoscopy

    Wang, Wen-Hung; Lin, Yen-Chun; Chen, Wen-Cheng; Chen, Miao-Fen; Chen, Chih-Cheng; Lee, Kam-Fai

    2012-01-01

    Purpose: This study evaluated the feasibility of screening mucosal recurrent nasopharyngeal carcinoma with narrow-band imaging (NBI) endoscopy. Methods and Materials: One hundred and six patients were enrolled. All patients underwent conventional white-light (WL) endoscopic examination of the nasopharynx followed by NBI endoscopy. Biopsies were performed if recurrence was suspected. Results: We identified 32 suspected lesions by endoscopy in WL and/or NBI mode. Scattered brown spots (BS) were identified in 22 patients, and 4 of the 22 who had negative MRI findings were histopathologically confirmed to be neoplasias that were successfully removed via endoscopy. A comparison of the visualization in NBI closer view corresponded to histopathological findings in 22 BS, and the prevalence rates of neoplasias in tail signs, round signs, and irregularities signs were 0% (0/6), 0% (0/7), and 44.4% (4/9), respectively (p = 0.048). The sensitivity, specificity, and diagnostic capability were 37.5%, 92.9% and 0.652 for WL, 87.5%, 74.5% and 0.810 for NBI, and 87.5%, 87.8%, and 0.876 for NBI closer view, respectively. NBI closer view was effective in increasing specificity compared with NBI alone (87.8% vs. 74.5%, p < 0.05), and in increasing sensitivity and diagnostic capability compared to WL alone (87.5% vs. 37.5%, p < 0.05; 0.876 vs. 0.652, p = 0.0001). Conclusions: Although NBI in endoscopy can improve sensitivity of mucosal recurrent nasopharyngeal neoplasias, false-positive (nonneoplasia BS) results may be obtained in areas with nonspecific inflammatory changes due to postradiation effects. NBI closer view not only can offer a timely, convenient, and highly reliable assessment of mucosal recurrent nasopharyngeal carcinoma, it can also make endoscopic removal possible.

  2. Diagnostic Performance of Narrow Band Imaging for Laryngeal Cancer: A Systematic Review and Meta-analysis.

    Sun, Changling; Han, Xue; Li, Xiaoying; Zhang, Yayun; Du, Xiaodong

    2017-04-01

    Objective To evaluate the performance of narrow band imaging (NBI) for the diagnosis of laryngeal cancer and to compare the diagnostic value of NBI with that of white light endoscopy. Data Sources PubMed, Embase, Cochrane Library, and CNKI databases. Review Methods Data analyses were performed with Meta-DiSc. The updated Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess study quality and potential bias. Publication bias was assessed with the Deeks's asymmetry test. The protocol used in this article has been published on PROSPERO and is in accordance with the PRISMA checklist. The registry number for this study is CRD42015025866. Results Six studies including 716 lesions were included in this meta-analysis. The pooled sensitivity, specificity, and diagnostic odds ratio for the NBI diagnosis of laryngeal cancer were 0.94 (95% confidence interval [95% CI]: 0.91-0.96), 0.89 (95% CI: 0.85-0.92), and 142.12 (95% CI: 46.42-435.15), respectively, and the area under receiver operating characteristics curve was 0.97. Among the 6 studies, 3 evaluated the diagnostic value of white light endoscopy, with a sensitivity of 0.81 (95% CI: 0.76-0.86), a specificity of 0.92 (95% CI: 0.88-0.95), and a diagnostic odds ratio of 33.82 (95% CI: 14.76-77.49). The evaluation of heterogeneity, calculated per the diagnostic odds ratio, gave an I 2 of 66%. No marked publication bias ( P = .84) was detected in this meta-analysis. Conclusion The sensitivity of NBI is superior to white light endoscopy, and the potential value of NBI needs to be validated in future studies.

  3. OLGA- and OLGIM-based staging of gastritis using narrow-band imaging magnifying endoscopy.

    Saka, Akiko; Yagi, Kazuyoshi; Nimura, Satoshi

    2015-11-01

    As atrophic gastritis and intestinal metaplasia as a result of Helicobacter pylori are considered risk factors for gastric cancer, it is important to assess their severity. In the West, the operative link for gastritis assessment (OLGA) and operative link for gastric intestinal metaplasia assessment (OLGIM) staging systems based on biopsy have been widely adopted. In Japan, however, narrow-band imaging (NBI)-magnifying endoscopic diagnosis of gastric mucosal inflammation, atrophy, and intestinal metaplasia has been reported to be fairly accurate. Therefore, we investigated the practicality of NBI-magnifying endoscopy (NBI-ME) for gastritis staging. We enrolled 55 patients, in whom NBI-ME was used to score the lesser curvature of the antrum (antrum) and the lesser curvature of the lower body (corpus). The NBI-ME score classification was established from images obtained beforehand, and then biopsy specimens taken from the observed areas were scored according to histological findings. The NBI-ME and histology scores were then compared. Furthermore, we assessed the NBI-ME and histology stages using a combination of scores for the antrum and corpus, and divided the stages into two risk groups: low and high. The degree to which the stage assessed by NBI-ME approximated that assessed by histology was then ascertained. Degree of correspondence between the NBI-ME and histology scores was 69.1% for the antrum and 72.7% for the corpus, and that between the high- and low-risk groups was 89.1%. Staging of gastritis using NBI-ME approximates that based on histology, and would be a practical alternative to the latter. © 2015 The Authors. Digestive Endoscopy © 2015 Japan Gastroenterological Endoscopy Society.

  4. Colour evaluation in scars: tristimulus colorimeter, narrow-band simple reflectance meter or subjective evaluation?

    Draaijers, Lieneke J; Tempelman, Fenike R H; Botman, Yvonne A M; Kreis, Robert W; Middelkoop, Esther; van Zuijlen, Paul P M

    2004-03-01

    The evaluation of scar colour is, at present, usually limited to an assessment according to a scar assessment scale. Although useful, these assessment scales only evaluate subjectively the degree of scar colour. In this study, the reliability of the subjective assessment of scar colour by observers is compared to the reliability of the measurements of two objective colour measurement instruments. Four independent observers subjectively assessed the vascularisation and pigmentation of 49 scar areas in 20 patients. The degree of vascularisation and pigmentation was scored according to a scale ranging from '1', when it appeared to be like healthy skin, to '10', which corresponds to the worst imaginable outcome of vascularisation or pigmentation. The observers also scored the pigmentation categories of the scar (hypopigmention, hyperpigmention or mixed pigmentation). Finally, each observer measured the scar areas with a tristimulus colorimeter (Minolta Chromameter) and a narrow-band simple reflectance meter (DermaSpectrometer). A single observer could reliably carry out measurements of the DermaSpectrometer and the Minolta Chromameter for the evaluation of scar colour (r = 0.72). The vascularisation of scars could also be assessed reliably with a single observer (r = 0.76) whereas for a reliable assessment of pigmentation at least three observers were necessary (r > or = 0.77). The agreement between the observers for the pigmentation categories also turned out to be unacceptably low (k = 0.349). This study shows that an overall evaluation of scar colour with the DermaSpectrometer and the Minolta Chromameter is more reliable than the evaluation of scar colour with observers. Of both instruments for measuring scar colour, we prefer, because of its feasibility, the DermaSpectrometer.

  5. Ultrabright, narrow-band photon-pair source for atomic quantum memories

    Tsai, Pin-Ju; Chen, Ying-Cheng

    2018-06-01

    We demonstrate an ultrabright, narrow-band and frequency-tunable photon-pair source based on cavity-enhanced spontaneous parametric down conversion (SPDC) which is compatible with atomic transition of rubidium D 2-line (780 nm) or cesium D 2-line (852 nm). With the pump beam alternating between a high and a low power phase, the output is switching between the optical parametric oscillator (OPO) and photon-pair generation mode. We utilize the OPO output light to lock the cavity length to maintain the double resonances of signal and idler, as well as to lock the signal frequency to cesium atomic transition. With a type-II phase matching and a double-passed pump scheme such that the cluster frequency spacing is larger than the SPDC bandwidth, the photon-pair output is in a nearly single-mode operation as confirmed by a scanning Fabry–Perot interferometer with its output detected by a photomultiplier. The achieved generation and detection rates are 7.24× {10}5 and 6142 s‑1 mW‑1, respectively. The correlation time of the photon pair is 21.6(2.2) ns, corresponding to a bandwidth of 2π × 6.6(6) MHz. The spectral brightness is 1.06× {10}5 s‑1 mW‑1 MHz‑1. This is a relatively high value under a single-mode operation with the cavity-SPDC scheme. The generated single photons can be readily used in experiments related to atomic quantum memories.

  6. Narrow band quantitative and multivariate electroencephalogram analysis of peri-adolescent period.

    Martinez, E I Rodríguez; Barriga-Paulino, C I; Zapata, M I; Chinchilla, C; López-Jiménez, A M; Gómez, C M

    2012-08-24

    The peri-adolescent period is a crucial developmental moment of transition from childhood to emergent adulthood. The present report analyses the differences in Power Spectrum (PS) of the Electroencephalogram (EEG) between late childhood (24 children between 8 and 13 years old) and young adulthood (24 young adults between 18 and 23 years old). The narrow band analysis of the Electroencephalogram was computed in the frequency range of 0-20 Hz. The analysis of mean and variance suggested that six frequency ranges presented a different rate of maturation at these ages, namely: low delta, delta-theta, low alpha, high alpha, low beta and high beta. For most of these bands the maturation seems to occur later in anterior sites than posterior sites. Correlational analysis showed a lower pattern of correlation between different frequencies in children than in young adults, suggesting a certain asynchrony in the maturation of different rhythms. The topographical analysis revealed similar topographies of the different rhythms in children and young adults. Principal Component Analysis (PCA) demonstrated the same internal structure for the Electroencephalogram of both age groups. Principal Component Analysis allowed to separate four subcomponents in the alpha range. All these subcomponents peaked at a lower frequency in children than in young adults. The present approaches complement and solve some of the incertitudes when the classical brain broad rhythm analysis is applied. Children have a higher absolute power than young adults for frequency ranges between 0-20 Hz, the correlation of Power Spectrum (PS) with age and the variance age comparison showed that there are six ranges of frequencies that can distinguish the level of EEG maturation in children and adults. The establishment of maturational order of different frequencies and its possible maturational interdependence would require a complete series including all the different ages.

  7. Superconductivity in narrow-band systems with local nonretarded attractive interactions

    Micnas, R.; Ranninger, J.; Robaszkiewicz, S.

    1990-01-01

    In narrow-band systems electrons can interact with each other via a short-range nonretarded attractive potential. The origin of such an effective local attraction can be polaronic or it can be due to a coupling between electrons and excitons or plasmons. It can also result from purely chemical (electronic) mechanisms, especially in compounds with elements favoring disproportionation of valent states. These mechanisms are discussed and an exhaustive list of materials in which such local electron pairing occurs is given. The authors review the thermodynamic and electromagnetic properties of such systems in several limiting scenarios: (i) Systems with on-site pairing which can be described by the extended negative-U Hubbard model. The strong-attraction limit of this model, at which it reduces to a system of tightly bound electron pairs (bipolarons) on a lattice, is extensively discussed. These electron pairs behaving as hard-core charged bosons can exhibit a superconducting state analogous to that of superfluid 4 He II. The changeover from weak-attraction BCS-like superconductivity to the superfluidity of charged hard-core bosons is examined. (ii) Systems with intersite pairing described by an extended Hubbard model with U>0 and nearest-neighbor attraction and/or nearest-neighbor spin exchange as well as correlated hopping. (iii) A mixture of local pairs and itinerant electrons interacting via a charge-exchange mechanism giving rise to a mutually induced superconductivity in both subsystems. The authors discuss to what extent the picture of local pairing, and in particular superfluidity of hard-core charged bosons on a lattice, can be an explanation for the superconducting and normal-state properties of the high-T c oxides: doped BaBiO 3 and the cuprates

  8. HMB-45 Study Before and After Narrow-Band (311 nm Ultraviolet B Treatment in Vitiligo

    Moosavi

    2015-06-01

    Full Text Available Background Vitiligo is an acquired disease in which the loss of functional melanocytes results in depigmented macules and patches. Over the years, wide arrays of markers for melanocytes have been described, including human melanoma black 45 (HMB-45. Narrow-band ultraviolet B (NB-UVB therapy is one of the therapeutic modalities for vitiligo. Objectives We sought to detect HMB-45 staining after 30 sessions of NB-UVB therapy in vitiligo and perivitiliginous skin. Patients and Methods All the participants were planned to have 30 sessions of NB-UVB therapy with 724 lamps (FS, 72 T, 12-HO Daavlin MED at 311 nm wavelengths. The patients underwent skin sampling from lesional and perilesional area before and after 30 sessions of treatment. The skin biopsies were sent to the laboratory for light microscopy and immunohistochemical study. The evaluation of HMB-45 was based on the quantitative method, measuring the number of positive stained cells. Clinical response was defined as repigmentation in three categories: more than 75%; between 40% and 75%; and less than 40%. The data were analyzed using SPSS (version 17. Results Twenty-nine patients completed the study. The Wilcoxon test showed a meaningful relation between HMB-45 staining before and after NB-UVB treatment in perilesional skin. We did not find a meaningful relation between HMB-45 staining before and after treatment regarding the mean age, gender, mean duration of disease, and initial lesional area (P = 0.55, P = 0.41, P = 0.55, and P = 0.87, respectively. After 30 sessions of NB-UVB therapy, repigmentation was less than 40% in 8 (27.6%, 40 - 75% in 7 (24.1%, and more than 75% in 6 patients. Conclusions The HMB-45 stain strength significantly changed after treatment in perilesional skin.

  9. Assessing the Temperature Dependence of Narrow-Band Raman Water Vapor Lidar Measurements: A Practical Approach

    Whiteman, David N.; Venable, Demetrius D.; Walker, Monique; Cardirola, Martin; Sakai, Tetsu; Veselovskii, Igor

    2013-01-01

    Narrow-band detection of the Raman water vapor spectrum using the lidar technique introduces a concern over the temperature dependence of the Raman spectrum. Various groups have addressed this issue either by trying to minimize the temperature dependence to the point where it can be ignored or by correcting for whatever degree of temperature dependence exists. The traditional technique for performing either of these entails accurately measuring both the laser output wavelength and the water vapor spectral passband with combined uncertainty of approximately 0.01 nm. However, uncertainty in interference filter center wavelengths and laser output wavelengths can be this large or larger. These combined uncertainties translate into uncertainties in the magnitude of the temperature dependence of the Raman lidar water vapor measurement of 3% or more. We present here an alternate approach for accurately determining the temperature dependence of the Raman lidar water vapor measurement. This alternate approach entails acquiring sequential atmospheric profiles using the lidar while scanning the channel passband across portions of the Raman water vapor Q-branch. This scanning is accomplished either by tilt-tuning an interference filter or by scanning the output of a spectrometer. Through this process a peak in the transmitted intensity can be discerned in a manner that defines the spectral location of the channel passband with respect to the laser output wavelength to much higher accuracy than that achieved with standard laboratory techniques. Given the peak of the water vapor signal intensity curve, determined using the techniques described here, and an approximate knowledge of atmospheric temperature, the temperature dependence of a given Raman lidar profile can be determined with accuracy of 0.5% or better. A Mathematica notebook that demonstrates the calculations used here is available from the lead author.

  10. Next-generation narrow band imaging system for colonic polyp detection: a prospective multicenter randomized trial.

    Horimatsu, Takahiro; Sano, Yasushi; Tanaka, Shinji; Kawamura, Takuji; Saito, Shoichi; Iwatate, Mineo; Oka, Shiro; Uno, Koji; Yoshimura, Kenichi; Ishikawa, Hideki; Muto, Manabu; Tajiri, Hisao

    2015-07-01

    Previous studies have yielded conflicting results on the colonic polyp detection rate with narrow-band imaging (NBI) compared with white-light imaging (WLI). We compared the mean number of colonic polyps detected per patient for NBI versus WLI using a next-generation NBI system (EVIS LUCERA ELITE; Olympus Medical Systems) used with standard-definition (SD) colonoscopy and wide-angle (WA) colonoscopy. this study is a 2 × 2 factorial, prospective, multicenter randomized controlled trial. this study was conducted at five academic centers in Japan. patients were allocated to one of four groups: (1) WLI with SD colonoscopy (H260AZI), (2) NBI with SD colonoscopy (H260AZI), (3) WLI with WA colonoscopy (CF-HQ290), and (4) NBI with WA colonoscopy (CF-HQ290). the mean numbers of polyps detected per patient were compared between the four groups: WLI with/without WA colonoscopy and NBI with/without WA colonoscopy. Of the 454 patients recruited, 431 patients were enrolled. The total numbers of polyps detected by WLI with SD, NBI with SD, WLI with WA, and NBI with WA were 164, 176, 188, and 241, respectively. The mean number of polyps detected per patient was significantly higher in the NBI group than in the WLI group (2.01 vs 1.56; P = 0.032). The rate was not higher in the WA group than in the SD group (1.97 vs 1.61; P = 0.089). Although WA colonoscopy did not improve the polyp detection, next-generation NBI colonoscopy represents a significant improvement in the detection of colonic polyps.

  11. Diagnostic Performance of Narrow Band Imaging for Nasopharyngeal Cancer: A Systematic Review and Meta-analysis.

    Sun, Changling; Zhang, Yayun; Han, Xue; Du, Xiaodong

    2018-03-01

    Objective The purposes of this study were to verify the effectiveness of the narrow band imaging (NBI) system in diagnosing nasopharyngeal cancer (NPC) as compared with white light endoscopy. Data Sources PubMed, Cochrane Library, EMBASE, CNKI, and Wan Fang databases. Review Methods Data analyses were performed with Meta-Disc. The updated Quality Assessment of Diagnostic Accuracy Studies-2 tool was used to assess study quality and potential bias. Publication bias was assessed with a Deeks asymmetry test. The registry number of the protocol published on PROSPERO is CRD42015026244. Results This meta-analysis included 10 studies of 1337 lesions. For NBI diagnosis of NPC, the pooled values were as follows: sensitivity, 0.83 (95% CI, 0.80-0.86); specificity, 0.91 (95% CI, 0.89-0.93); positive likelihood ratio, 8.82 (95% CI, 5.12-15.21); negative likelihood ratio, 0.18 (95% CI, 0.12-0.27); and diagnostic odds ratio, 65.73 (95% CI, 36.74-117.60). The area under the curve was 0.9549. For white light endoscopy in diagnosing NPC, the pooled values were as follows: sensitivity, 0.79 (95% CI, 0.75-0.83); specificity, 0.87 (95% CI, 0.84-0.90); positive likelihood ratio, 5.02 (95% CI, 1.99-12.65); negative likelihood ratio, 0.34 (95% CI, 0.24-0.49); and diagnostic odds ratio, 16.89 (95% CI, 5.98-47.66). The area under the curve was 0.8627. The evaluation of heterogeneity, calculated per the diagnostic odds ratio, gave an I 2 of 0.326. No marked publication bias ( P = .68) existed in this meta-analysis. Conclusion The sensitivity and specificity of NBI for the diagnosis of NPC are similar to those of white light endoscopy, and the potential value of NBI for the diagnosis of NPC needs to be validated further.

  12. Optimized fan-shaped chiral metamaterial as an ultrathin narrow-band circular polarizer at visible frequencies

    He, Yizhuo; Wang, Xinghai; Ingram, Whitney; Ai, Bin; Zhao, Yiping

    2018-04-01

    Chiral metamaterials have the great ability to manipulate the circular polarizations of light, which can be utilized to build ultrathin circular polarizers. Here we build a narrow-band circular polarizer at visible frequencies based on plasmonic fan-shaped chiral nanostructures. In order to achieve the best optical performance, we systematically investigate how different fabrication factors affect the chiral optical response of the fan-shaped chiral nanostructures, including incident angle of vapor depositions, nanostructure thickness, and post-deposition annealing. The optimized fan-shaped nanostructures show two narrow bands for different circular polarizations with the maximum extinction ratios 7.5 and 6.9 located at wavelength 687 nm and 774 nm, respectively.

  13. Charge separation dynamics in a narrow band gap polymer-PbS nanocrystal blend for efficient hybrid solar cells

    Piliego, Claudia; Manca, Marianna; Kroon, Renee; Yarema, Maksym; Szendrei, Krisztina; Andersson, Mats R.; Heiss, Wolfgang; Loi, Maria A.

    2012-01-01

    We have demonstrated efficient hybrid solar cells based on lead sulfide (PbS) nanocrystals and a narrow band gap polymer, poly[{2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl}-alt-{[2,2'-(1,4-phenylene)bis-thiophene]-5,5'-diyl}], (PDPPTPT). An opportune mixing of

  14. THE COSMIC INFRARED BACKGROUND EXPERIMENT (CIBER): THE NARROW-BAND SPECTROMETER

    Korngut, P. M.; Bock, J. [Jet Propulsion Laboratory (JPL), National Aeronautics and Space Administration (NASA), Pasadena, CA 91109 (United States); Renbarger, T.; Keating, B. [Department of Physics, University of California, San Diego, San Diego, CA 92093 (United States); Arai, T.; Matsumoto, T.; Matsuura, S. [Department of Space Astronomy and Astrophysics, Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA), Sagamihara, Kanagawa 252-5210 (Japan); Battle, J.; Hristov, V.; Lanz, A.; Levenson, L. R.; Mason, P. [Department of Physics, California Institute of Technology, Pasadena, CA 91125 (United States); Brown, S. W.; Lykke, K. R.; Smith, A. W. [Sensor Science Division, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899 (United States); Cooray, A. [Center for Cosmology, University of California, Irvine, Irvine, CA 92697 (United States); Kim, M. G. [Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Lee, D. H.; Nam, U. W. [Korea Astronomy and Space Science Institute (KASI), Daejeon 305-348 (Korea, Republic of); Shultz, B., E-mail: pkorngut@caltech.edu [Materion Barr Precision Optics and Thin Film Coatings, Westford, MA 01886 (United States); and others

    2013-08-15

    We have developed a near-infrared spectrometer designed to measure the absolute intensity of the solar 854.2 nm Ca II Fraunhofer line, scattered by interplanetary dust, in the zodiacal light (ZL) spectrum. Based on the known equivalent line width in the solar spectrum, this measurement can derive the zodiacal brightness, testing models of the ZL based on morphology that are used to determine the extragalactic background light in absolute photometry measurements. The spectrometer is based on a simple high-resolution tipped filter placed in front of a compact camera with wide-field refractive optics to provide the large optical throughput and high sensitivity required for rocket-borne observations. We discuss the instrument requirements for an accurate measurement of the absolute ZL brightness, the measured laboratory characterization, and the instrument performance in flight.

  15. Photoelectric transfer device

    Shinomiya, Takuji; Murao, Fumihide

    1987-12-07

    Concerning the conventional photoelectric transfer device, a short-circuit current of photodiodes is switched over with MOS transistors. However, since the backgate voltage of the MOS transistor which is to be used as the switching element, is provided by the source voltage, the leakage current between the backgate and the source/drain/ channel is great and due to this leakage current, errors occur in the photoelectric transfer power output. Especially, when the leakage current of the photodiodes is small, the error becomes large. In order to solve the above problem, this invention aims at offering a photoelectric transfer device which can provide the high precision photoelectric transfer even the short-circuit current generated in the photodiodes is small and proposes a photoelectric transfer device in which the backgate voltage of the MOS transistor switching over the short-circuit current of the photodiodes is made equal to the electric potential of the mutually connected anodes (or cathodes) of the photodiodes. (3 figs)

  16. Full-sky survey searching for ultra-narrow-band artificial CW signals: analysis of the results of Project META

    Lemarchand, Guillermo A.

    1996-06-01

    Project META (Megachannel ExtraTerrestrial Assay), a full-sky survey for artificial narrow-band signals, has been conducted from the Harvard/Smithsonian 26 m radiotelescope at Agassiz Station and from one of the two 30 m radiotelescopes of the Instituto Argentino de Radioastronomia (IAR). The search was performed near the 1420 MHz line of neutral hydrogen, and its second harmonic, using two 8.4 X 10(superscript 6) channel Fourier spectrometers of 0.05 Hz resolution and 400 kHz of instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earth's rotation, which provides a characteristic changing signature for narrow-band signals of extraterrestrial origin. Among the 6 X 10(superscript 13) spectral channels searched in the northern hemisphere, Horowitz and Sagan reported 37 candidates events exceeding the average threshold of 1.7 X 10(superscript -23) W m(superscript -2), while in the southern hemisphere among 2 X 10(superscript 13) spectral channels analyzed we found 19 events exceeding the same threshold. The strongest signals that survive culling for terrestrial interference lie in or near the Galactic Plane. The first high resolution southern target search around 71 stars (-90 degrees intelligence. It is showed that these narrow-band non-repeating 'events' found by Project META can be generated by (a) radiometer noise fluctuations, (b) a population of constant galactic sources which undergo deep fading and amplification due to interstellar scintillation, consistent with ETI transmissions and (c) real, transient signals of either terrestrial or extraterrestrial origin. The Bayesian test shows that hypothesis (b) and (c) are both highly preferred to (a), but the first two are about equally likely. Using this analysis we discuss the best observing strategies to determine the real origin of these 'events'.

  17. Observation of coherently enhanced tunable narrow-band terahertz transition radiation from a relativistic sub-picosecond electron bunch train

    Piot, P.; Maxwell, T. J.; Sun, Y.-E; Ruan, J.; Lumpkin, A. H.; Thurman-Keup, R.; Rihaoui, M. M.

    2011-01-01

    We experimentally demonstrate the production of narrow-band (δf/f≅20% at f≅0.5THz) transition radiation with tunable frequency over [0.37, 0.86] THz. The radiation is produced as a train of sub-picosecond relativistic electron bunches transits at the vacuum-aluminum interface of an aluminum converter screen. The bunch train is generated via a transverse-to-longitudinal phase space exchange technique. We also show a possible application of modulated beams to extend the dynamical range of a popular bunch length diagnostic technique based on the spectral analysis of coherent radiation.

  18. Optical Observations of M81 Galaxy Group in Narrow Band [SII] and H_alpha Filters: Holmberg IX

    Arbutina, B.

    2009-12-01

    Full Text Available We present observations of the nearby tidal dwarf galaxy Holmberg IX in M81 galaxy group in narrow band [SII] and H$alpha$ filters, carried out in March and November 2008 with the 2m RCC telescope at NAO Rozhen, Bulgaria. Our search for resident supernova remnants (identified as sources with enhanced [SII] emission relative to their H$alpha$ emission in this galaxy yielded no sources of this kind, besides M&H 10-11 or HoIX X-1. Nevertheless, we found a number of objects with significant H$alpha$ emission that probably represent uncatalogued HII regions.

  19. Laser-produced lithium plasma as a narrow-band extended ultraviolet radiation source for photoelectron spectroscopy.

    Schriever, G; Mager, S; Naweed, A; Engel, A; Bergmann, K; Lebert, R

    1998-03-01

    Extended ultraviolet (EUV) emission characteristics of a laser-produced lithium plasma are determined with regard to the requirements of x-ray photoelectron spectroscopy. The main features of interest are spectral distribution, photon flux, bandwidth, source size, and emission duration. Laser-produced lithium plasmas are characterized as emitters of intense narrow-band EUV radiation. It can be estimated that the lithium Lyman-alpha line emission in combination with an ellipsoidal silicon/molybdenum multilayer mirror is a suitable EUV source for an x-ray photoelectron spectroscopy microscope with a 50-meV energy resolution and a 10-mum lateral resolution.

  20. Charge separation dynamics in a narrow band gap polymer-PbS nanocrystal blend for efficient hybrid solar cells

    Piliego, Claudia; Manca, Marianna; Kroon, Renee; Yarema, Maksym; Szendrei, Krisztina; Andersson, Mats R.; Heiss, Wolfgang; Loi, Maria A.

    2012-01-01

    We have demonstrated efficient hybrid solar cells based on lead sulfide (PbS) nanocrystals and a narrow band gap polymer, poly[{2,5-bis(2-hexyldecyl)-2,3,5,6-tetrahydro-3,6-dioxopyrrolo[3,4-c]pyrrole-1,4-diyl}-alt-{[2,2'-(1,4-phenylene)bis-thiophene]-5,5'-diyl}], (PDPPTPT). An opportune mixing of the two materials led to the formation of an energetically favorable bulk hetero-junction with a broad spectral response. Using a basic device structure, we reached a power conversion efficiency of s...

  1. Five years of Project META - An all-sky narrow-band radio search for extraterrestrial signals

    Horowitz, Paul; Sagan, Carl

    1993-01-01

    We have conducted a five-year search of the northern sky (delta between 30 and 60 deg) for narrow-band radio signals near the 1420 MHz line of neutral hydrogen, and its second harmonic, using an 8.4 x 10 exp 6 channel Fourier spectrometer of 0.05 Hz resolution and 400 kHz instantaneous bandwidth. The observing frequency was corrected both for motions with respect to three astronomical inertial frames, and for the effect of Earth's rotation, which provides a characteristic changing Doppler signature for narrow-band signals of extraterrestrial origin. Among the 6 x 10 exp 13 spectral channels searched, we have found 37 candidate events exceeding the average detection threshold of 1.7 x 10 exp -23 W/sq m, none of which was detected upon reobservation. The strongest of these appear to be dominated by rare processor errors. However, the strongest signals that survive culling for terrestrial interference lie in or near the Galactic plane. We describe the search and candidate events, and set limits on the prevalence of supercivilizations transmitting Doppler-precompensated beacons at H I or its second harmonic. We conclude with recommendations for future searches, based upon these findings, and a description of our next-generation search system.

  2. Narrow-band 1, 2, 3, 4, 8, 16 and 24 cycles/360o angular frequency filters

    Simas M.L.B.

    2002-01-01

    Full Text Available We measured human frequency response functions for seven angular frequency filters whose test frequencies were centered at 1, 2, 3, 4, 8, 16 or 24 cycles/360º using a supra-threshold summation method. The seven functions of 17 experimental conditions each were measured nine times for five observers. For the arbitrarily selected filter phases, the maximum summation effect occurred at test frequency for filters at 1, 2, 3, 4 and 8 cycles/360º. For both 16 and 24 cycles/360º test frequencies, maximum summation occurred at the lower harmonics. These results allow us to conclude that there are narrow-band angular frequency filters operating somehow in the human visual system either through summation or inhibition of specific frequency ranges. Furthermore, as a general result, it appears that addition of higher angular frequencies to lower ones disturbs low angular frequency perception (i.e., 1, 2, 3 and 4 cycles/360º, whereas addition of lower harmonics to higher ones seems to improve detection of high angular frequency harmonics (i.e., 8, 16 and 24 cycles/360º. Finally, we discuss the possible involvement of coupled radial and angular frequency filters in face perception using an example where narrow-band low angular frequency filters could have a major role.

  3. Study of Oxidative Stress in Vitiligo and Use of Narrow Band UVB-311 as a Method of Treatment

    Fawzy, N.; Rashed, L.

    2012-01-01

    Vitiligo is an acquired depigmenting disease characterized by circumscribed depigmenting macules devoid of identifiable melanocytes. The disease has uncertain aetiopathogenesis. The aim of this research is to estimate the level of superoxide dismutase (SOD) and catalase (CAT) as antioxidants and Nitric oxide and superoxide anion as oxidants in vitiligo patients and evaluate the clinical effectiveness of narrow band UVB (NB-UVB-311) as a method of treatment and repairing the oxidative stress-induced damage. This study included twenty vitiligo patients and fifteen-age and sex matched control. There was statistically significant increase in the levels of SOD in active vitiligo lesions compared to control (P<0.001). There was statistically significant decrease in the level of CAT in vitiligo skin lesions compared to skin of control. After using NB-UVB- 311 the level of SOD was significantly decreased and CAT level was significantly increased (P<0.001). There was statistically significant increase in the level of nitric oxide and superoxide in vitiligo patients compared to control. After using NB-UVB-311 as treatment, the level of nitric oxide and superoxide anion was significantly decreased (P<0.001) in vitiligo patients. These results provide some evidence regarding the oxidant /antioxidant balance in vitiligo patients and the positive role of narrow band UVB- 311 as a treatment of vitiligo

  4. Photoelectric installations in Tunisia

    Darkazalli, G

    1983-01-01

    Four autonomous photoelectric power plants (FEU) have been in operation since February, 1983 in the village of Hamman Biadha. One of them based on a solar battery (SB) with a capacity of 29 kilowatts made of modules by the Solar Power Corporation (U.S.A.), has a storage battery (AB) with a capacity of 360 kilowatts per hour, and serves to supply alternating current, 220 volt voltage electric power to stores, a mill, a hospital, a school and streetlights near them and 22 houses. The solar battery is maintained in a maximal power mode which increases the energy production by 5 to 10 percent. As the charge of the storage battery is reduced below the assigned levels, the appropriate consumers are shut off. The daily energy productivity of the photoelectric power plant is 119 kilowatt hours per day in July and 65 kilowatt hours per day in December. A smaller variant of this photoelectric power plant with a capacity of 1.5 kilowatts provides electric power to a farm. The other two photoelectric power plants drive the irrigation systems for a greenhouse with an area of 10exp4 square meters and a fruit garden. The maximum productivity of each of them is 750 cubic meters per month with a delivery of 17 meters.

  5. Research on mechanism of the large-amplitude and narrow-band vibration of a flexible flat plate in the rectangular 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); State Nuclear Power Software Development Center, Building 1, Compound No. 29, North Third Ring Road, Xicheng District, Beijing 100029 (China); Lu Daogang [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration experiment was performed. Black-Right-Pointing-Pointer The added mass theory was used to analyze the test plates' natural vibration characteristics in static water. Black-Right-Pointing-Pointer The occurring condition of the large amplitude and narrow band vibration was investigated. Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration mechanism was investigated. - Abstract: Further experiments and theoretical analysis were performed to investigate mechanism of the large-amplitude and narrow-band vibration behavior of a flexible flat plate in a rectangular channel. Test plates with different thicknesses were adopted in the FIV experiments. The natural vibration characteristics of the flexible flat plates in air were tested, and the added mass theory of column was used to analyze the flexible flat plates' natural vibration characteristics in static water. It was found that the natural vibration frequency of a certain test plate in static water is approximately within the main vibration frequency band of the plate when it was induced to vibrate with the large-amplitude and narrow-band in the rectangular channel. It can be concluded that the harmonic between the flowing fluid and the vibrating plate is one of the key reasons to induce the large-amplitude and narrow-band vibration phenomenon. The occurring condition of the phenomenon and some important narrow-band vibration characteristics of a foursquare fix-supported flexible flat plate were investigated.

  6. Automatic Photoelectric Telescope Service

    Genet, R.M.; Boyd, L.J.; Kissell, K.E.; Crawford, D.L.; Hall, D.S.; BDM Corp., McLean, VA; Kitt Peak National Observatory, Tucson, AZ; Dyer Observatory, Nashville, TN)

    1987-01-01

    Automatic observatories have the potential of gathering sizable amounts of high-quality astronomical data at low cost. The Automatic Photoelectric Telescope Service (APT Service) has realized this potential and is routinely making photometric observations of a large number of variable stars. However, without observers to provide on-site monitoring, it was necessary to incorporate special quality checks into the operation of the APT Service at its multiple automatic telescope installation on Mount Hopkins. 18 references

  7. Three-Dimensional Simulation of DRIE Process Based on the Narrow Band Level Set and Monte Carlo Method

    Jia-Cheng Yu

    2018-02-01

    Full Text Available A three-dimensional topography simulation of deep reactive ion etching (DRIE is developed based on the narrow band level set method for surface evolution and Monte Carlo method for flux distribution. The advanced level set method is implemented to simulate the time-related movements of etched surface. In the meanwhile, accelerated by ray tracing algorithm, the Monte Carlo method incorporates all dominant physical and chemical mechanisms such as ion-enhanced etching, ballistic transport, ion scattering, and sidewall passivation. The modified models of charged particles and neutral particles are epitomized to determine the contributions of etching rate. The effects such as scalloping effect and lag effect are investigated in simulations and experiments. Besides, the quantitative analyses are conducted to measure the simulation error. Finally, this simulator will be served as an accurate prediction tool for some MEMS fabrications.

  8. Micro-Bunched Beam Production at FAST for Narrow Band THz Generation Using a Slit-Mask

    Hyun, J. [Sokendai, Tsukuba; Crawford, D. [Fermilab; Edstrom Jr, D. [Fermilab; Ruan, J. [Fermilab; Santucci, J. [Fermilab; Thurman-Keup, R. [Fermilab; Sen, T. [Fermilab; Thangaraj, J. C. [Fermilab

    2018-04-01

    We discuss simulations and experiments on creating micro-bunch beams for generating narrow band THz radiation at the Fermilab Accelerator Science and Technology (FAST) facility. The low-energy electron beamline at FAST consists of a photoinjector-based RF gun, two Lband superconducting accelerating cavities, a chicane, and a beam dump. The electron bunches are lengthened with cavity phases set off-crest for better longitudinal separation and then micro-bunched with a slit-mask installed in the chicane. We carried out the experiments with 30 MeV electron beams and detected signals of the micro-bunching using a skew quadrupole magnet in the chicane. In this paper, the details of micro-bunch beam production, the detection of micro-bunching and comparison with simulations are described.

  9. Laterally Spreading Tumors of the Colon During High Resolution Colonoscopy with Narrow Band Imaging and Acetic Acid Chromoscopy

    V.A. Yakovenko

    2015-02-01

    Materials and Methods. 1632 colonoscopy protocols were studied: 735 — by using video colonoscope Olympus CF-HQ190L and 897 — Olympus CF-150. Results and Discussion. In study group, adenoma detection rate was higher than in control one: 0.78 (571/735 vs. 0.47 (422/897, p < 0.00001; c2 = 157.9. Adenoma detection index was 3.6 times higher in study group than in control one: 2.9 (2,104/735 vs. 0.8 (708/897. Laterally spreading tumors were diagnosed 2.2 times more often in study group than in control one: 22 % (187/735 vs. 10 % (85/897, p < 0.00001; c2 = 53.6. Conclusions. High resolution colonoscopy with narrow band imaging and acetic acid chromoscopy has a high diagnostic value for detection of laterally spreading tumors of the colon.

  10. A theory for narrow-banded radio bursts at Uranus - MHD surface waves as an energy driver

    Farrell, W. M.; Curtis, S. A.; Desch, M. D.; Lepping, R. P.

    1992-01-01

    A possible scenario for the generation of the narrow-banded radio bursts detected at Uranus by the Voyager 2 planetary radio astronomy experiment is described. In order to account for the emission burstiness which occurs on time scales of hundreds of milliseconds, it is proposed that ULF magnetic surface turbulence generated at the frontside magnetopause propagates down the open/closed field line boundary and mode-converts to kinetic Alfven waves (KAW) deep within the polar cusp. The oscillating KAW potentials then drive a transient electron stream that creates the bursty radio emission. To substantiate these ideas, Voyager 2 magnetometer measurements of enhanced ULF magnetic activity at the frontside magnetopause are shown. It is demonstrated analytically that such magnetic turbulence should mode-convert deep in the cusp at a radial distance of 3 RU.

  11. Narrow-band tunable terahertz emission from ferrimagnetic Mn{sub 3-x}Ga thin films

    Awari, N. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); University of Groningen, 9747 AG Groningen (Netherlands); Kovalev, S., E-mail: s.kovalev@hzdr.de, E-mail: c.fowley@hzdr.de, E-mail: rodek@tcd.ie; Fowley, C., E-mail: s.kovalev@hzdr.de, E-mail: c.fowley@hzdr.de, E-mail: rodek@tcd.ie; Green, B.; Yildirim, O.; Lindner, J.; Fassbender, J.; Deac, A. M.; Gensch, M. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Rode, K., E-mail: s.kovalev@hzdr.de, E-mail: c.fowley@hzdr.de, E-mail: rodek@tcd.ie; Lau, Y.-C.; Betto, D.; Thiyagarajah, N.; Coey, J. M. D. [CRANN, AMBER and School of Physics, Trinity College Dublin, Dublin 2 (Ireland); Gallardo, R. A. [Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, 2390123 Valparíso (Chile)

    2016-07-18

    Narrow-band terahertz emission from coherently excited spin precession in metallic ferrimagnetic Mn{sub 3-x}Ga Heusler alloy nanofilms has been observed. The efficiency of the emission, per nanometer film thickness, is comparable or higher than that of classical laser-driven terahertz sources based on optical rectification. The center frequency of the emission from the films can be tuned precisely via the film composition in the range of 0.20–0.35 THz, making this type of metallic film a candidate for efficient on-chip terahertz emitters. Terahertz emission spectroscopy is furthermore shown to be a sensitive probe of magnetic properties of ultra-thin films.

  12. First-principles study of direct and narrow band gap semiconducting β-CuGaO2

    Nguyen, Manh Cuong; Zhao, Xin; Wang, Cai-Zhuang; Ho, Kai-Ming

    2015-01-01

    Semiconducting oxides have attracted much attention due to their great stability in air or water and the abundance of oxygen. Recent success in synthesizing a metastable phase of CuGaO 2 with direct narrow band gap opens up new applications of semiconducting oxides as absorber layer for photovoltaics. Using first-principles density functional theory calculations, we investigate the thermodynamic and mechanical stabilities as well as the structural and electronic properties of the β-CuGaO 2 phase. Our calculations show that the β-CuGaO 2 structure is dynamically and mechanically stable. The energy band gap is confirmed to be direct at the Γ point of Brillouin zone. The optical absorption occurs right at the band gap edge and the density of states near the valance band maximum is large, inducing an intense absorption of light as observed in experiment. (paper)

  13. Water vapor transmittance models for narrow bands in the 13 to 19 μm spectral region

    Weichel, R.L.

    1983-10-01

    The purpose of this report is to document the development of water vapor transmittance models for narrow bands (satellite sensor channels) in the 13 to 19 μm spectral region. The models are the result of research efforts of the author in 1971-1972 while on active duty with the US Air Force at the Air Force Global Weather Central (AFGWC). The models were developed for application in studies involving a temperature profiling sensor system carried aboard the satellites of the Defense Meteorological Satellite Program (DMSP), formerly DAPP. Recently, (Lovill et al., 1978; Luther et al., 1981) the models were implemented for studies concerned with methodologies to retrieve total atmospheric column ozone from measurements of newer DMSP Block 5D series satellite sensors with similar channels (see Nichols, 1975)

  14. Suppression of narrow-band interference in a PN spread-spectrum receiver using a CTD-based adaptive filter

    Saulnier, G. J.; Das, P.; Milstein, L. B.

    1984-11-01

    Analytical results have shown that adaptive filtering can be a powerful tool for the rejection of narrow-band interference in a spread-spectrum receiver. However, the complexity of adaptive filtering hardware has hindered the experimental verification of these results. This paper describes a new adaptive filter architecture for implementing the Widrow-Hoff LMS algorithm while using only two multipliers regardless of filter order. This hardware simplification is achieved through the use of a burst processing technique. A 16-tap version of this adaptive filter constructed using charge-transfer devices (CTD's) is used to suppress a single tone jammer in a direct sequence spread-spectrum receiver. Probability of error measurements demonstrating the effectiveness of the adaptive filter for suppressing the single tone jammer along with simulation results for the optimal Weiner-Hopf filter are presented and discussed.

  15. Stability of the split-band solution and energy gap in the narrow-band region of the Hubbard model

    Arai, T.; Cohen, M.H.

    1980-01-01

    By inserting quasielectron energies ω calculated from the fully renormalized Green's function of the Hubbard model obtained in the preceding paper into the exact expression of Galitskii and Migdal, the ground-state energy, the chemical potential, and the dynamic- and thermodynamic-stability conditions are calculated in the narrow-band region. The results show that as long as the interaction energy I is finite, electrons in the narrow-band region do not obey the Landau theory of Fermi liquids, and a gap appears between the lowest quasielectron energy ω and the chemical potential μ for any occupation n, regardless of whether the lower band is exactly filled or not. This unusual behavior is possible because, when an electron is added to the system of N electrons, the whole system relaxes due to the strong interaction, introducing a relaxation energy difference between the two quantities. We also show that all previous solutions which exhibit the split-band structure, including Hubbard's work, yield the same conclusion that electrons do not behave like Landau quasiparticles. However, the energy gap is calculated to be negative at least for some occupations n, demonstrating the dynamic instability of those solutions. They also exhibit thermodynamic instability for certain occupations, while the fully renormalized solution, having sufficient electron correlations built in, satisfies the dynamic and thermodynamic stability conditions for all occupations. When the lower band is nearly filled, the nature of the solution is shown to change, making the coherent motion of electrons with fixed k values more difficult. In the pathological limit where I=infinity, however, the gap vanishes, yielding a metallic state

  16. 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.

  17. Fluorene-based narrow-band-gap copolymers for red light- emitting diodes and bulk heterojunction photovoltaic cells

    Mingliang SUN; Li WANG; Yangjun XIA; Bin DU; Ransheng LIU; Yong CAO

    2008-01-01

    A series of narrow band-gap conjugated copo-lymers (PFO-DDQ) derived from 9,9-dioctylfluorene (DOF) and 2,3-dimethyl-5,8-dithien-2-yl-quinoxalines (DDQ) is prepaid by the palladium-catalyzed Suzuki coupling reaction with the molar feed ratio of DDQ at around 1%,5%,15%,30% and 50%,respectively.The obtained polymers are readily soluble in common organic solvents.The solutions and the thin solid films of the copolymers absorb light from 300-590 nm with two absorbance.peaks at around 380 and 490 nm.The intens-ity of 490 nm peak increases with the increasing DDQ content in the polymers.Efficient energy transfer due to exciton trapping on narrow-band-gap DDQ sites has been observed.The PL emission consists exclusively of DDQ unit emission at around 591 643 nm depending on the DDQ content in solid film.The EL emission peaks are red-shifted from 580 nm for PFO-DDQ1 to 635 nm for PFO-DDQ50.The highest external quantum efficiency achieved with the device configuration ITO/PEDOT/ PVK/PFO-DDQt5/Ba/A1 is 1.33% with a luminous effi-ciency 1.54 cd/A.Bulk heterojunction photovoltaic cells fabricated from composite films of PFO-DDQ30 copoly-mer and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as electron donor and electron acceptor,respect-ively in device configuration:ITO/PEDOT:PSS/PFO-DDQ30:PCBM/PFPNBr/Al shows power conversion effi-ciencies of 1.18% with open-circuit voltage (Voc) of 0.90 V and short-circuit current density (Jsc) of 2.66 mA/cm2 under an AM1.5 solar simulator (100 mW/cm2).The photocurrent response wavelengths of the PVCs based on PFO-DDQ30/PCBM blends covers 300-700 nm.This indicates that these kinds of low band-gap polymers are promising candidates for polymeric solar cells and red light-emitting diodes.

  18. Photoelectric photometry of the Am star HR = V423 Per

    Jerzykiewicz, M.

    1989-01-01

    This spectroscopic binary is the largest amplitude variable among Am stars. UBV observations of the star are presented. They show that in 1964 and 1965 it was constant in B and was only marginally variable in U. The hypothesis of the ellipsoidal variability of HR 976 is then discussed and found untenable. It is pointed out that this result may reopen the issue of light variability of Am stars. 10 refs., 2 figs., 2 tabs. (author)

  19. Gas Distributions in Comet ISON’s Coma: Concurrent Integral-Field Spectroscopy and Narrow-band Imaging.

    Schmidt, Carl; Johnson, Robert E.; Baumgardner, Jeffrey; Mendillo, Michael

    2014-11-01

    At a solar distance of 0.44 AU, Oort cloud comet C/2012 S1 (ISON) exhibited an outburst phase that was observed by small telescopes at the McDonald Observatory. In conjunction with narrow-band (14Å) imaging over a wide-field, an image-slicer spectrograph ( 20,000) simultaneously measured the spatial distribution of ISON’s coma over a 1.6 x 2.7 arcminute field made up of 246 individual spectra. More than fifty emission lines from C2, NH2, CO, H2O+ and Na were observed within a single Echelle order spanning 5868Å to 5930Å. Spatial reconstructions of these species reveal that ISON’s coma was quite elongated several thousand km along the axis perpendicular to its motion. The ion tail appeared distinctly broader than the neutral Na tail, providing strong evidence that Na in the coma did not originate by dissociative recombination of a sodium bearing molecular ion. Production rates increased from 1.6 ± 0.3 x 1023 to 5.8 ± 1 x 1023 Na atoms/s within 24 hours, outgassing much less than comparable comets relative to ISON’s water production. The anti-sunward Na tail was imaged >106 km from the nucleus. Its distribution indicates origins both near the nucleus and in the dust tail, with the ratio of these Na sources varying on hourly timescales due to outburst activity.

  20. Sensitivity and specificity of narrow-band imaging nasoendoscopy compared to histopathology results in patients with suspected nasopharyngeal carcinoma

    Adham, M.; Musa, Z.; Lisnawati; Suryati, I.

    2017-08-01

    Nasopharyngeal carcinoma (NPC) is a disease which is prevalent in developing countries like Indonesia. There were 164 new cases of nasopharyngeal carcinoma in the ear, nose, and throat (ENT) oncology outpatient clinic of the Cipto Mangunkusumo hospital in 2014, and 142 cases in 2015. Unfortunately, almost all of these cases presented at an advanced stage. The success of nasopharyngeal carcinoma treatment is largely determined by the stage when patients are diagnosed; it is critical to diagnose NPC as early as possible. Narrow-band imaging (NBI) is an endoscopic instrument with a light system that can improve the visualization of blood vessels of mucosal epithelial malignant tumors. NBI is expected to help clinicians to assess whether a lesion is malignant or not; to do so, it is important to know the value of sensitivity and specificity. This study is a cross-sectional form of a diagnostic test which was performed in the outpatient clinic of the ENT Head and Neck Surgery Department for the Cipto Mangunkusumo Hospital, from January to June 2016, and involved 56 subjects. Patients with a nasopharyngeal mass discovered by physical examination or imaging, and a suspected nasopharyngeal carcinoma were included as a subject. An NBI examination and biopsy was performed locally. Based on this research, NBI could be used as a screening tool for nasopharyngeal carcinoma with high sensitivity (100%), but with a low specificity result (6.7%).

  1. The Role of Narrow Band Imaging in the Detection of Recurrent Laryngeal and Hypopharyngeal Cancer after Curative Radiotherapy

    Michal Zabrodsky

    2014-01-01

    Full Text Available Narrow band imaging is considered a significant improvement in the possibility of detecting early mucosal lesion of the upper aerodigestive tract. Early detection of mucosal neoplastic lesions is of utmost importance for patients survival. There is evidence that, especially in patients previously treated by means of curative radiotherapy or chemoradiotherapy, the early detection rate of recurrent disease is quite low. The aim of this study was to prove whether the videoendoscopy coupled with NBI might help detect recurrent or secondary tumors of the upper aerodigestive tract. 66 patients previously treated by means of RT or CRT with curative intent were enrolled in the study. All patients underwent transnasal flexible videoendoscopy with NBI mode under local anesthesia. When a suspicious lesion was identified in an ambulatory setting, its nature was proved histologically. Many of these changes were not identifiable by means of conventional white light (WL endoscopy. The accuracy, sensitivity, specificity, and positive and negative predictive value of the method are very high (88%, 92%, 76%, 96%, and 91%, resp.. Results demonstrate that outpatient transnasal endoscopy with NBI is an excellent method for the follow-up of patients with carcinomas of the larynx and the hypopharynx primarily treated with radiotherapy.

  2. High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures

    Kapaev, V. V.; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N.

    2013-01-01

    The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schrödinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In 0.53 Ga 0.47 As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V dc in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

  3. THE ACCURACY OF Hβ CCD PHOTOMETRY

    C. Kim

    1994-12-01

    Full Text Available We have undertaken CCD observations of field standard stars with Hβ photometric system to investigate the reliability of Hβ CCD photometry. Flat fielding with dome flat and sky flat for Hβw and Hβn filter was compared with that of B filter in UBV system and, from these, we have not found any difference. It was confirmed that there is a good linear relationship between our Hβ values observed with 2.3m reflector and standard values. However, Hβ values observed with 60cm reflector at Sobaeksan Astronomy Observatory showed very poor relationship. To investigate the accuracy of Hβ CCD photometry for fainter objects, open cluster NGC2437 was observed and reduced with DoPHOT, and the results were compared with those for photoelectric photometry of Stetson (1981.

  4. Enhanced dissociation of charge-transfer states in narrow band gap polymer:fullerene solar cells processed with 1,8-octanedithiol

    Moet, D.J.D.; Lenes, M.; Morana, M.; Azimi, H.; Brabec, C.J.; Blom, P.W.M.

    2010-01-01

    The improved photovoltaic performance of narrow band gap polymer:fullerene solar cells processed from solutions containing small amounts of 1,8-octanedithiol is analyzed by modeling of the experimental photocurrent. In contrast to devices that are spin coated from pristine chlorobenzene, these cells

  5. Enhanced dissociation of charge-transfer states in narrow band gap polymer : fullerene solar cells processed with 1,8-octanedithiol

    Moet, D. J. D.; Lenes, M.; Morana, M.; Azimi, H.; Brabec, C. J.; Blom, P. W. M.

    2010-01-01

    The improved photovoltaic performance of narrow band gap polymer:fullerene solar cells processed from solutions containing small amounts of 1,8-octanedithiol is analyzed by modeling of the experimental photocurrent. In contrast to devices that are spin coated from pristine chlorobenzene, these cells

  6. Low-dose narrow-band UVB phototherapy combined with topical therapy is effective in psoriasis and does not inhibit systemic T-cell activation

    de Rie, M. A.; Out, T. A.; Bos, J. D.

    1998-01-01

    Psoriasis is a chronic T-cell-mediated inflammatory skin disease which can be treated with topical medication, phototherapy or systemic medication. A subgroup of psoriatic patients does not respond to monotherapy and needs combination therapy. We used low-dose narrow-band UVB phototherapy, combined

  7. The role of high-resolution endoscopy and narrow-band imaging in the evaluation of upper GI neoplasia in familial adenomatous polyposis

    Lopez-Ceron, Maria; van den Broek, Frank J. C.; Mathus-Vliegen, Elisabeth M.; Boparai, Karam S.; van Eeden, Susanne; Fockens, Paul; Dekker, Evelien

    2013-01-01

    The Spigelman classification stratifies cancer risk in familial adenomatous polyposis (FAP) patients with duodenal adenomatosis. High-resolution endoscopy (HRE) and narrow-band imaging (NBI) may identify lesions at high risk. To compare HRE and NBI for the detection of duodenal and gastric polyps

  8. Development and Validation of a Classification System to Identify High-Grade Dysplasia and Esophageal Adenocarcinoma in Barrett's Esophagus Using Narrow-Band Imaging

    Sharma, Prateek; Bergman, Jacques J. G. H. M.; Goda, Kenichi; Kato, Mototsugu; Messmann, Helmut; Alsop, Benjamin R.; Gupta, Neil; Vennalaganti, Prashanth; Hall, Matt; Konda, Vani; Koons, Ann; Penner, Olga; Goldblum, John R.; Waxman, Irving

    2016-01-01

    Although several classification systems have been proposed for characterization of Barrett's esophagus (BE) surface patterns based on narrow-band imaging (NBI), none have been widely accepted. The Barrett's International NBI Group (BING) aimed to develop and validate an NBI classification system for

  9. Wide applicability of high-Tc pairing originating from coexisting wide and incipient narrow bands in quasi-one-dimensional systems

    Matsumoto, Karin; Ogura, Daisuke; Kuroki, Kazuhiko

    2018-01-01

    We study superconductivity in the Hubbard model on various quasi-one-dimensional lattices with coexisting wide and narrow bands originating from multiple sites within a unit cell, where each site corresponds to a single orbital. The systems studied are the two-leg and three-leg ladders, the diamond chain, and the crisscross ladder. These one-dimensional lattices are weakly coupled to form two-dimensional (quasi-one-dimensional) ones, and the fluctuation exchange approximation is adopted to study spin-fluctuation-mediated superconductivity. When one of the bands is perfectly flat and the Fermi level intersecting the wide band is placed in the vicinity of, but not within, the flat band, superconductivity arising from the interband scattering processes is found to be strongly enhanced owing to the combination of the light electron mass of the wide band and the strong pairing interaction due to the large density of states of the flat band. Even when the narrow band has finite bandwidth, the pairing mechanism still works since the edge of the narrow band, due to its large density of states, plays the role of the flat band. The results indicate the wide applicability of the high-Tc pairing mechanism due to coexisting wide and "incipient" narrow bands in quasi-one-dimensional systems.

  10. Near infrared photometry of violent star formation regions

    Melnick, J.; Terlevich, R.; Moles, M.

    1985-01-01

    Near infrared broad band photometry and CO indices for a significant number of Violent Star Formation Regions are presented. The existence of a narrow correlation between W (Hβ) and IR colour is confirmed. The interpretation of this relation as an age sequence implies a correlation between CO index and W(Hβ) which is not found. It is argued however that this failure is most likely a consequence of using narrow band filters to determine CO indices in objects with strong emission-line spectra. (author)

  11. Oligothiophene-Indandione-Linked Narrow-Band Gap Molecules: Impact of π-Conjugated Chain Length on Photovoltaic Performance.

    Komiyama, Hideaki; To, Takahiro; Furukawa, Seiichi; Hidaka, Yu; Shin, Woong; Ichikawa, Takahiro; Arai, Ryota; Yasuda, Takuma

    2018-04-04

    Solution-processed organic solar cells (OSCs) based on narrow-band gap small molecules hold great promise as next-generation energy-converting devices. In this paper, we focus on a family of A-π-D-π-A-type small molecules, namely, BDT- nT-ID ( n = 1-4) oligomers, consisting of benzo[1,2- b:4,5- b']dithiophene (BDT) as the central electron-donating (D) core, 1,3-indandione (ID) as the terminal electron-accepting (A) units, and two regioregular oligo(3-hexylthiophene)s ( nT) with different numbers of thiophene rings as the π-bridging units, and elucidate their structure-property-function relationships. The effects of the length of the π-bridging nT units on the optical absorption, thermal behavior, morphology, hole mobility, and OSC performance were systematically investigated. All oligomers exhibited broad and intense visible photoabsorption in the 400-700 nm range. The photovoltaic performances of bulk heterojunction OSCs based on BDT- nT-IDs as donors and a fullerene derivative as an acceptor were studied. Among these oligomers, BDT-2T-ID, incorporating bithiophene as the π-bridging units, showed better photovoltaic performance with a maximum power conversion efficiency as high as 6.9% under AM 1.5G illumination without using solvent additives or postdeposition treatments. These favorable properties originated from the well-developed interpenetrating network morphology of BDT-2T-ID, with larger domain sizes in the photoactive layer. Even though all oligomers have the same A-D-A main backbone, structural modulation of the π-bridging nT length was found to impact their self-organization and nanostructure formation in the solid state, as well as the corresponding OSC device performance.

  12. Advantages of magnifying narrow-band imaging for diagnosing colorectal cancer coexisting with sessile serrated adenoma/polyp.

    Chino, Akiko; Osumi, Hiroki; Kishihara, Teruhito; Morishige, Kenjiro; Ishikawa, Hirotaka; Tamegai, Yoshiro; Igarashi, Masahiro

    2016-04-01

    In the present study, we investigated the advantages of narrow-band imaging (NBI) for efficient diagnosis of sessile serrated adenoma/polyp (SSA/P). The main objective of this study was to analyze the characteristic features of cancer coexisting with serrated lesion by carrying out NBI. We evaluated 264 non-malignant serrated lesions by using three modalities (conventional white light colonoscopy, magnifying chromoendoscopy, and magnifying NBI). Of the evaluated cancer cases with serrated lesions, 37 fulfilled the inclusion criteria. In diagnosing non-malignant SSA/P, an expanded crypt opening (ECO) under magnifying NBI is a useful sign. One hundred and twenty-five lesions (87%) of observed ECO were, at the same time, detected to have type II open pit pattern, which is known to be a valuable indicator when using magnifying chromoendoscopy. ECO had high sensitivity of 80% for identifying SSA/P, with 62% specificity and 83% positive predictive value (PPV). In detecting the cancer with SSA/P, irregular vessels under magnifying NBI were frequently observed with 100% sensitivity and 99% specificity, 86% PPV and 100% negative predictive value. A focus on irregular vessels in serrated lesions might be useful for identification of cancer with SSA/P. This is an advantage of carrying out magnifying NBI in addition to being used simultaneously with other modalities by switching, and observations can be made by using wash-in water alone. We can carry out advanced examinations for selected lesions with irregular vessels. To confirm cancerous demarcation and invasion depth, a combination of all three aforementioned modalities should be done. © 2016 The Authors Digestive Endoscopy © 2016 Japan Gastroenterological Endoscopy Society.

  13. SUPRATHERMAL ELECTRON STRAHL WIDTHS IN THE PRESENCE OF NARROW-BAND WHISTLER WAVES IN THE SOLAR WIND

    Kajdič, P. [Instituto de Geofísica, Universidad Nacional Autónoma de México, Mexico City (Mexico); Alexandrova, O.; Maksimovic, M.; Lacombe, C. [LESIA, Observatoire de Paris, PSL Research University, CNRS, UPMC UniversitéParis 06, Université Paris-Diderot, 5 Place Jules Janssen, F-92190 Meudon (France); Fazakerley, A. N., E-mail: primoz@geofisica.unam.mx [Mullard Space Science Laboratory, University College London (United Kingdom)

    2016-12-20

    We perform the first statistical study of the effects of the interaction of suprathermal electrons with narrow-band whistler mode waves in the solar wind (SW). We show that this interaction does occur and that it is associated with enhanced widths of the so-called strahl component. The latter is directed along the interplanetary magnetic field away from the Sun. We do the study by comparing the strahl pitch angle widths in the SW at 1 AU in the absence of large scale discontinuities and transient structures, such as interplanetary shocks, interplanetary coronal mass ejections, stream interaction regions, etc. during times when the whistler mode waves were present and when they were absent. This is done by using the data from two Cluster instruments: Spatio Temporal Analysis of Field Fluctuations experiment (STAFF) data in the frequency range between ∼0.1 and ∼200 Hz were used for determining the wave properties and Plasma Electron And Current Experiment (PEACE) data sets at 12 central energies between ∼57 eV (equivalent to ∼10 typical electron thermal energies in the SW, E{sub T}) and ∼676 eV (∼113 E{sub T}) for pitch angle measurements. Statistical analysis shows that, during the intervals with the whistler waves, the strahl component on average exhibits pitch angle widths between 2° and 12° larger than during the intervals when these waves are not present. The largest difference is obtained for the electron central energy of ∼344 eV (∼57 ET).

  14. Chronic exposure of Sk-1 hairless mice to narrow-band ultraviolet A (320-355 nm)

    Menter, J.M.; Sayre, R.M.; Etemadi, A.A.; Agin, P.P.; Wills, I.

    1996-01-01

    Several recent investigations collectively suggest that the role of ultraviolet A (UVA) in chronic actinic skin damage may be greater than originally thought. In the present work, the output of a xenon-arc solar-simulator passed through a Bausch and Lomb monochromator in conjunction with a 2-mm Schott WG-320 filter produced narrow-band UVA centered at 338 nm, half-band width 24 nm, I 0 =3.4±0.3 mW/cm 2 . We chronically irradiated 10 SK-1 albino hairless mice 5 times per week for 18 weeks, starting with 1.25 J/cm 2 , for 33 irradiation days, sequentially followed by 1.50 J/cm 2 (34 days), 1.8 J/cm 2 (10 days), 2.0 J/cm 2 (22 days) to afford a total UVA dose of 154.3 J/cm 2 over 99 irradiation days. Erythema was noted clinically by day 6, which persisted throughout the irradiation. During the irradiation period, some scaling, consistent with mild epidermal hyperplasia was noted during irradiation days 37-56. This response later regressed despite continued chronic irradiation. Hematoxylin and eosin examination immediately after the final irradiation revealed a mild inflammatory response, with some dermal restructuring. At the end of the experiment, no significant signs of epidermal hyperplasia or (pre)malignant lesions were seen, although some stratum corneum thickening was noted. Marked dermal collagen damage and moderate elastosis was also evident. We believe that the observed differences in results reported in previous studies are in large part due to differences in light sources and irradiation protocols. (au)

  15. 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.)

  16. Diagnostic efficacy of magnifying endoscopy with narrow-band imaging for gastric neoplasms: a meta-analysis.

    Xiuhe Lv

    Full Text Available Magnifying endoscopy with narrow-band imaging (ME-NBI is a novel, image-enhanced endoscopic technique for differentiating gastrointestinal neoplasms and potentially enabling pathological diagnosis.The aim of this analysis was to assess the diagnostic performance of ME-NBI for gastric neoplasms.We performed a systematic search of the PubMed, EMbase, Web of Science, and Cochrane Library databases for relevant studies. Meta-DiSc (version 1.4 and STATA (version 11.0 software were used for the data analysis. Random effects models were used to assess diagnostic efficacy. Heterogeneity was tested by the Q statistic and I2 statistic. Meta-regression was used to analyze the sources of heterogeneity.A total of 10 studies, with 2151 lesions, were included. The pooled characteristics of these studies were as follows: sensitivity 0.85 (95% confidence interval [CI]: 0.81-0.89, specificity 0.96 (95% confidence interval [CI]: 0.95-0.97, and area under the curve (AUC 0.9647. In the subgroup analysis, which compared the diagnostic efficacy of ME-NBI and white light imaging (WLI, the pooled sensitivity and specificity of ME-NBI were 0.87 (95% CI: 0.80-0.92 and 0.93 (95% CI: 0.90-0.95, respectively, and the area under the curve (AUC was 0.9556. In contrast, the pooled sensitivity and specificity of WLI were 0.61 (95% CI: 0.53-0.69 and 0.65 (95% CI: 0.60-0.69, respectively, and the area under the curve (AUC was 0.6772.ME-NBI presents a high diagnostic value for gastric neoplasms and has a high specificity.

  17. Narrow-band imaging (NBI for improving the assessment of vocal fold leukoplakia and overcoming the umbrella effect.

    H Klimza

    Full Text Available It is crucial to find a balance between functional and oncological outcome when choosing an adequate method for the management of vocal fold leukoplakia. Therefore, a detailed examination is a milestone in the decision-making process.To examine whether narrow-band imaging (NBI can be helpful in vocal fold assessment in the case of leukoplakia and how to overcome the "umbrella effect"- understood as the submucosal vascular pattern hidden under the plaque.Prospective cohort of 41 consecutive patients. Inclusion criteria: vocal fold leukoplakia, no previous procedures (surgery, radiotherapy, and preoperative endoscopy with an optical filter for NBI. Two groups: "suspicious" and "normal", according to the submucosal microvascular pattern of peripheral regions of the mucosa surrounding the plaque, were distinguished. Patients were qualified for a full-thickness or partial-thickness biopsy, respectively. Criteria defining suspected characters were well-demarcated brownish areas with scattered brown spots corresponding to type IV, Va, Vb, and Vc NI classifications.In 22/41 (53.7% patients with "suspected" microvascular pattern, full-thickness biopsy was performed. Moderate and severe dysplasia was revealed in 15 type IV and 7 type Va NI patients. In 19/41 (46.3% patients with proper NBI vessel pattern treated by partial-thickness biopsy, hyperkeratosis was diagnosed. There was a strong correlation between the NBI pattern and final histology: Chi2 (2 = 41.0 (p = 0.0000.The results demonstrate that NBI endoscopic assessment of the submucosal microvascular pattern of mucosa surrounding the plaque can be an effective method to categorise the risk in vocal fold leukoplakia prior to treatment.

  18. SUPRATHERMAL ELECTRON STRAHL WIDTHS IN THE PRESENCE OF NARROW-BAND WHISTLER WAVES IN THE SOLAR WIND

    Kajdič, P.; Alexandrova, O.; Maksimovic, M.; Lacombe, C.; Fazakerley, A. N.

    2016-01-01

    We perform the first statistical study of the effects of the interaction of suprathermal electrons with narrow-band whistler mode waves in the solar wind (SW). We show that this interaction does occur and that it is associated with enhanced widths of the so-called strahl component. The latter is directed along the interplanetary magnetic field away from the Sun. We do the study by comparing the strahl pitch angle widths in the SW at 1 AU in the absence of large scale discontinuities and transient structures, such as interplanetary shocks, interplanetary coronal mass ejections, stream interaction regions, etc. during times when the whistler mode waves were present and when they were absent. This is done by using the data from two Cluster instruments: Spatio Temporal Analysis of Field Fluctuations experiment (STAFF) data in the frequency range between ∼0.1 and ∼200 Hz were used for determining the wave properties and Plasma Electron And Current Experiment (PEACE) data sets at 12 central energies between ∼57 eV (equivalent to ∼10 typical electron thermal energies in the SW, E T ) and ∼676 eV (∼113 E T ) for pitch angle measurements. Statistical analysis shows that, during the intervals with the whistler waves, the strahl component on average exhibits pitch angle widths between 2° and 12° larger than during the intervals when these waves are not present. The largest difference is obtained for the electron central energy of ∼344 eV (∼57 ET).

  19. Investigation of mucosal pattern of gastric antrum using magnifying narrow-band imaging in patients with chronic atrophic fundic gastritis.

    Yamasaki, Yasushi; Uedo, Noriya; Kanzaki, Hiromitsu; Kato, Minoru; Hamada, Kenta; Aoi, Kenji; Tonai, Yusuke; Matsuura, Noriko; Kanesaka, Takashi; Yamashina, Takeshi; Akasaka, Tomofumi; Hanaoka, Noboru; Takeuchi, Yoji; Higashino, Koji; Ishihara, Ryu; Tomita, Yasuhiko; Iishi, Hiroyasu

    2017-01-01

    Magnifying narrow-band imaging (M-NBI) can reportedly help predict the presence and distribution of atrophy and intestinal metaplasia in the gastric corpus. However, the micro-mucosal pattern of the antrum shown by M-NBI differs from that of the corpus. We studied the distribution and histology of the micro-mucosal pattern in the antrum based on magnifying endoscopy. Endoscopic images of the greater curvature of the antrum were evaluated in 50 patients with chronic atrophic fundic gastritis (CAFG). The extent of CAFG was evaluated by autofluorescence imaging. The micro-mucosal pattern was evaluated by M-NBI and classified into groove and white villiform types. The localization of white villiform type mucosa was classified into three types in relation to the areae gastricae : null, central, and segmental types. Biopsies were taken from regions showing different micro-mucosal patterns. Associations among the extent of CAFG, micro-mucosal pattern, and histology were examined. As the extent of CAFG increased, the proportion of white villiform type mucosa increased, whereas that of groove type mucosa decreased (P=0.022). In patients with extensive CAFG, most of the areae gastricae was composed of the segmental or central type of white villiform type mucosa (P=0.044). The white villiform type mucosa had significantly higher grades of atrophy (P=0.002) and intestinal metaplasia (P<0.001) than did the groove type mucosa. White villiform type mucosa is indicative of atrophy and intestinal metaplasia in the gastric antrum. It extends to the whole or central part of the areae gastricae as CAFG becomes more extensive.

  20. Office-based narrow band imaging-guided flexible laryngoscopy tissue sampling: A cost-effectiveness analysis evaluating its impact on Taiwanese health insurance program

    Fang, Tuan-Jen; Li, Hsueh-Yu; Liao, Chun-Ta; Chiang, Hui-Chen; Chen, I-How

    2015-01-01

    Narrow band imaging (NBI)-guided flexible laryngoscopy tissue sampling for laryngopharyngeal lesions is a novel technique. Patients underwent the procedure in an office-based setting without being sedated, which is different from the conventional technique performed using direct laryngoscopy. Although the feasibility and effects of this procedure were established, its financial impact on the institution and Taiwanese National Health Insurance program was not determined. Methods: This is a ...

  1. Multi-tap complex-coefficient incoherent microwave photonic filters based on optical single-sideband modulation and narrow band optical filtering.

    Sagues, Mikel; García Olcina, Raimundo; Loayssa, Alayn; Sales, Salvador; Capmany, José

    2008-01-07

    We propose a novel scheme to implement tunable multi-tap complex coefficient filters based on optical single sideband modulation and narrow band optical filtering. A four tap filter is experimentally demonstrated to highlight the enhanced tuning performance provided by complex coefficients. Optical processing is performed by the use of a cascade of four phase-shifted fiber Bragg gratings specifically fabricated for this purpose.

  2. A 1.1-1.9 GHz SETI SURVEY OF THE KEPLER FIELD. I. A SEARCH FOR NARROW-BAND EMISSION FROM SELECT TARGETS

    Siemion, Andrew P. V.; Korpela, Eric; Werthimer, Dan; Cobb, Jeff; Lebofsky, Matt; Marcy, Geoffrey W. [University of California, Berkeley, 110 Sproul Hall, Berkeley, CA 94720 (United States); Demorest, Paul; Maddalena, Ron J.; Langston, Glen [National Radio Astronomy Observatory, 520 Edgemont Rd Charlottesville, VA 22903 (United States); Howard, Andrew W. [Institute for Astronomy, University of Hawaii, 640 North A' ohoku Place, 209 Hilo, HI 96720-2700 (United States); Tarter, Jill [SETI Institute, 189 Bernardo Ave 100 Mountain View, CA 94043 (United States)

    2013-04-10

    We present a targeted search for narrow-band (<5 Hz) drifting sinusoidal radio emission from 86 stars in the Kepler field hosting confirmed or candidate exoplanets. Radio emission less than 5 Hz in spectral extent is currently known to only arise from artificial sources. The stars searched were chosen based on the properties of their putative exoplanets, including stars hosting candidates with 380 K > T{sub eq} > 230 K, stars with five or more detected candidates or stars with a super-Earth (R{sub p} < 3 R{sub Circled-Plus }) in a >50 day orbit. Baseband voltage data across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C. Byrd Green Bank Telescope between 2011 February and April and subsequently searched offline. No signals of extraterrestrial origin were found. We estimate that fewer than {approx}1% of transiting exoplanet systems host technological civilizations that are radio loud in narrow-band emission between 1 and 2 GHz at an equivalent isotropically radiated power (EIRP) of {approx}1.5 Multiplication-Sign 10{sup 21} erg s{sup -1}, approximately eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the Milky Way to be <10{sup -6} M{sub Sun }{sup -1}. Here we describe our observations, data reduction procedures and results.

  3. Peritoneal vascular density assessment using narrow-band imaging and vascular analysis software, and cytokine analysis in women with and without endometriosis.

    Kuroda, Keiji; Kitade, Mari; Kikuchi, Iwaho; Kumakiri, Jun; Matsuoka, Shozo; Kuroda, Masako; Takeda, Satoru

    2010-01-01

    The development and onset of endometriosis is associated with angiogenesis and angiogenic factors including cytokines. We analyzed intrapelvic conditions in women with endometriosis via vascular density assessment of grossly normal peritoneum and determination of cytokine levels in peritoneal fluid. Seventy-three patients underwent laparoscopic surgery because of gynecologic disease including endometriosis in our department using a narrow-band imaging system. Each patient was analyzed for peritoneal vascular density using commercially available vascular analysis software (SolemioENDO ProStudy; Olympus Corp, Tokyo, Japan). Each patient was also subjected to analysis of interleukin 6 (IL-6), IL-8, tumor necrosis factor-alpha, and vascular endothelial growth factor concentrations in peritoneal fluid. We defined 4 groups as follows: group 1, endometriosis: gonadotropin-releasing hormone (GnRH) agonist administration group (n=27); group 2, endometriosis: GnRH agonist nonadministration group (n=15); group 3, no endometriosis: GnRH agonist administration group (n=18); and group 4, no endometriosis: GnRH agonist nonadministration group (n=13). No significant differences in peritoneal vascular density between the 4 groups were found under conventional light; however, under narrow-band light, vascular density in the endometriosis groups (groups 1 and 2) was significantly higher. Cytokine analysis of the 4 groups determined that IL-6 and IL-8 concentrations were significantly higher compared with the no endometriosis groups (groups 3 and 4). Tumor necrosis factor-alpha and vascular endothelial growth factor concentrations were not significantly different between groups. In endometriosis, peritoneal vascular density was significantly higher as assessed using the narrow-band imaging system and SolemioENDO ProStudy, whereas GnRH agonist did not obviously decrease vascular density but IL-6 concentration was lower in the GnRH agonist administration group. Copyright (c) 2010 AAGL

  4. Simulation of the Application Layer in NarrowBand Networks with Conditional Data Injection XML Scheme Based on Universal Data Generator

    Ondrej Vondrous

    2017-01-01

    Full Text Available In this article, we would like to deal with challenges and analysis approaches in the area of narrow band communication networks. Especially those networks which use TCP/IP protocol family. We also present a new universal data generator for OMNeT++ simulation environment. We created this generator to satisfy the evaluation, stress testing and benchmarking demands of more and more complex industrial and the Internet of Things networks. We also present the methods for evaluation and comparison of results obtained from simulated and real TCP/IP based networks in this article.

  5. Long-Term Photometry of Very Slow Novae

    Chochol D.

    2003-12-01

    Full Text Available Long-term photographic, photoelectric and recent CCD photometry of the classical nova V723 Cas and symbiotic novae V1329 Cyg, PU Vul, V1016 Cyg and HM Sge were used to find their orbital periods. The arguments in favor of the presence of the third components in these systems are given. Physical processes, responsible for the brightness variations, are discussed.

  6. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    Feng, Liefeng, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng [Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, Faculty of Science, Tianjin University, Tianjin 300072 (China); Li, Yang [Business and Vocational College of Hainan, Haikou 570203 (China); Li, Ding; Hu, Xiaodong [Research Center for Wide Band Gap Semiconductors, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China); Li, Hongru, E-mail: fengliefeng@tju.edu.cn, E-mail: lihongru@nankai.edu.cn [State Key Laboratory for Medicinal Chemistry and Biology, College of Pharmacy, Nankai University, Tianjin 300071 (China)

    2015-04-15

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I{sub th}{sup l} and I{sub th}{sup u}, as shown in Fig. 2; I{sub th}{sup l} is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I{sub th}{sup u} is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V{sub j}) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I{sub th}{sup l} and I{sub th}{sup u}. The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region.

  7. Competitive behavior of photons contributing to junction voltage jump in narrow band-gap semiconductor multi-quantum-well laser diodes at lasing threshold

    Feng, Liefeng; Yang, Xiufang; Wang, Cunda; Yao, Dongsheng; Li, Yang; Li, Ding; Hu, Xiaodong; Li, Hongru

    2015-01-01

    The junction behavior of different narrow band-gap multi-quantum-well (MQW) laser diodes (LDs) confirmed that the jump in the junction voltage in the threshold region is a general characteristic of narrow band-gap LDs. The relative change in the 1310 nm LD is the most obvious. To analyze this sudden voltage change, the threshold region is divided into three stages by I th l and I th u , as shown in Fig. 2; I th l is the conventional threshold, and as long as the current is higher than this threshold, lasing exists and the IdV/dI-I plot drops suddenly; I th u is the steady lasing point, at which the separation of the quasi-Fermi levels of electron and holes across the active region (V j ) is suddenly pinned. Based on the evolutionary model of dissipative structure theory, the rate equations of the photons in a single-mode LD were deduced in detail at I th l and I th u . The results proved that the observed behavior of stimulated emission suddenly substituting for spontaneous emission, in a manner similar to biological evolution, must lead to a sudden increase in the injection carriers in the threshold region, which then causes the sudden increase in the junction voltage in this region

  8. Subharmonic response of a single-degree-of-freedom nonlinear vibro-impact system to a narrow-band random excitation.

    Haiwu, Rong; Wang, Xiangdong; Xu, Wei; Fang, Tong

    2009-08-01

    The subharmonic response of single-degree-of-freedom nonlinear vibro-impact oscillator with a one-sided barrier to narrow-band random excitation is investigated. The narrow-band random excitation used here is a filtered Gaussian white noise. The analysis is based on a special Zhuravlev transformation, which reduces the system to one without impacts, or velocity jumps, thereby permitting the applications of asymptotic averaging over the "fast" variables. The averaged stochastic equations are solved exactly by the method of moments for the mean-square response amplitude for the case of linear system with zero offset. A perturbation-based moment closure scheme is proposed and the formula of the mean-square amplitude is obtained approximately for the case of linear system with nonzero offset. The perturbation-based moment closure scheme is used once again to obtain the algebra equation of the mean-square amplitude of the response for the case of nonlinear system. The effects of damping, detuning, nonlinear intensity, bandwidth, and magnitudes of random excitations are analyzed. The theoretical analyses are verified by numerical results. Theoretical analyses and numerical simulations show that the peak amplitudes may be strongly reduced at large detunings or large nonlinear intensity.

  9. The visible to the near infrared narrow band acousto-optic tunable filter and the hyperspectral microscopic imaging on biomedicine study

    Zhang, Chunguang; Wang, Hao; Huang, Junfeng; Gao, Qiang

    2014-01-01

    Based on the parallel tangents momentum-matching condition, a narrow band noncollinear acousto-optic tunable filter (AOTF) using a single TeO 2 crystal is designed with the consideration of the birefringence and the rotatory property of the material. An effective setup is established to evaluate the performance of the designed AOTF. The experimental observed spectrum pattern of the diffracted light is nearly the same with the theoretical result. The measured tuning relationship between the diffracted central optical wavelength and acoustic frequency is in accordance with the theoretical prospect. The optical bandwidth of the diffracted light is as narrow as 1.88 nm when the central wavelength is 556.75 nm. The high spectral resolution is significant in practical applications of imaging AOTF. Additionally, the AOTF based hyperspectral microscopic imaging system is established. The stability and the image resolution of the designed narrow band AOTF are satisfying. Finally, the study of the biologic samples indicates the feasibility of our system on biomedicine. (paper)

  10. Utility of the cromoendoscopy and the narrow band image at colon polyps; Utilidad de la cromoendoscopia y la imagen de banda estrecha en los polipos de colon

    Perez Gonzalez, Teresita; Chao Gonzalez, Lissette; Tusen Toledo, Yunia, E-mail: teresitaperez@infomed.sld.cu [Centro de Investigaciones Medico Quirurgicas, La Habana (Cuba); others, and

    2013-07-01

    Colorrectal adenomas constitute the best characterized pre-malignancy injury in the development of the cancer in the colon. Colonoscopy with diagnostic and therapeutic aims is essential to prevent the cancer appearance. A prospective, descriptive and observational study was carried out in patients that assisted for colonoscopy at Medical Surgical Research Center from September 2010 to July 2011 The Kudo and the Sano-Emura classifications were used to determine the importance of the cromoendoscopy and the narrow band image at the time to identify histological nature of the polyps in the colon. Sensibility, specificity, positive and negative predictable values and the concordance degree were estimated. The morfology and the dysplasia degree were associated.

  11. How narrow-band and broad-band uvb irradiation influences the immunohistochemistry analyses of experimental animals’ skin – a comparative study. Part II

    Katarzyna Borowska

    2017-09-01

    Full Text Available This is the second part of the artcle series impact narrow-band UVB radiation (NB-UVB and broad-band UVB radiation (BB-UVB on experimental animals’ skin (white Wistar female rats. The aim of this comparative study was immunohistochemistry analyses containing expression of p53 protein. Expression of p53 protein was performed on two experimental groups. One – exposed to NB-UVB; the other – exposed to BB-UVB radiation. The results indicate that p53 protein takes an active part in the process of apoptosis that is induced by both NB-UVB and BB-UVB. The results showed an increase in p53 expressing cells following BB-UVB than NB-UVB phototherapy.

  12. HIGH RESOLUTION He i 10830 Å NARROW-BAND IMAGING OF AN M-CLASS FLARE. I. ANALYSIS OF SUNSPOT DYNAMICS DURING FLARING

    Wang, Ya; Su, Yingna; Hong, Zhenxiang; Ji, Haisheng [Key Laboratory of DMSA, Purple Mountain Observatory, CAS, Nanjing, 210008 (China); Zeng, Zhicheng; Goode, Philip R.; Cao, Wenda [Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States); Ji, Kaifan [Yunnan Astronomical Observatories, Kunming 650011 (China)

    2016-12-20

    In this paper, we report our first-step results of high resolution He i 10830 Å narrow-band imaging (bandpass: 0.5 Å) of an M1.8 class two-ribbon flare on 2012 July 5. The flare was observed with the 1.6 m aperture New Solar Telescope at Big Bear Solar Observatory. For this unique data set, sunspot dynamics during flaring were analyzed for the first time. By directly imaging the upper chromosphere, running penumbral waves are clearly seen as an outward extension of umbral flashes; both take the form of absorption in the 10830 Å narrow-band images. From a space–time image made of a slit cutting across a flare ribbon and the sunspot, we find that the dark lanes for umbral flashes and penumbral waves are obviously broadened after the flare. The most prominent feature is the sudden appearance of an oscillating absorption strip inside the ribbon when it sweeps into the sunspot’s penumbral and umbral regions. During each oscillation, outwardly propagating umbral flashes and subsequent penumbral waves rush out into the inwardly sweeping ribbon, followed by a return of the absorption strip with similar speed. We tentatively explain the phenomena as the result of a sudden increase in the density of ortho-helium atoms in the area of the sunspot being excited by the flare’s extreme ultraviolet illumination. This explanation is based on the observation that 10830 Å absorption around the sunspot area gets enhanced during the flare. Nevertheless, questions are still open and we need further well-devised observations to investigate the behavior of sunspot dynamics during flares.

  13. PHOTOELECTRIC OBSERVATIONS OF HD 8358

    Woo-Baik Lee

    1989-06-01

    Full Text Available UBV photoelectric observations of RS CVn type variable star HD 8358 were made using the 61cm reflector at Sobaeksan Astronomical Observatory. The data were obtained on 15 nights from October 1987 to December 1988. Double peaks of maximum light is seen from the light curve and continuous change of phase in notified from the times of maximum lights. The colors of October, 1987 - January, 1988 observations are bluer in ∆(b-u, but redder in ∆(u-b, than those of November -December, 1988 observations.

  14. Narrow-band imaging can increase the visibility of fibrin caps after bleeding of esophageal varices: a case with extensive esophageal candidiasis.

    Furuichi, Yoshihiro; Kasai, Yoshitaka; Takeuchi, Hirohito; Yoshimasu, Yuu; Kawai, Takashi; Sugimoto, Katsutoshi; Kobayashi, Yoshiyuki; Nakamura, Ikuo; Itoi, Takao

    2017-08-01

    A 58-year-old man with hepatitis B cirrhosis noticed black stools and underwent an endoscopy at a community hospital. The presence of esophageal varices (EVs) was confirmed, but the bleeding point was not found. He was referred to our institution and underwent a second endoscopy. Extensive white patches of esophageal candidiasis were visible on endoscopy by white-light imaging (WLI), but it was difficult to find the fibrin cap of the EVs. This was easier under narrow-band imaging (NBI), however, as the color turned red from absorption by hemoglobin adhered to it. We retrospectively measured the color differences (CD) between the fibrin cap and the surrounding mucosa 10 times using the CIE (L*a*b*) color space method. The median value of CD increased after NBI (13.9 → 43.0, p candidiasis, but the increased visibility of the fibrin cap by NBI enabled it to be found more easily. This is the first report of a case in which NBI was helpful in locating a fibrin cap of EVs.

  15. Clicking in a killer whale habitat: narrow-band, high-frequency biosonar clicks of harbour porpoise (Phocoena phocoena and Dall's porpoise (Phocoenoides dalli.

    Line A Kyhn

    Full Text Available Odontocetes produce a range of different echolocation clicks but four groups in different families have converged on producing the same stereotyped narrow band high frequency (NBHF click. In microchiropteran bats, sympatric species have evolved the use of different acoustic niches and subtly different echolocation signals to avoid competition among species. In this study, we examined whether similar adaptations are at play among sympatric porpoise species that use NBHF echolocation clicks. We used a six-element hydrophone array to record harbour and Dall's porpoises in British Columbia (BC, Canada, and harbour porpoises in Denmark. The click source properties of all porpoise groups were remarkably similar and had an average directivity index of 25 dB. Yet there was a small, but consistent and significant 4 kHz difference in centroid frequency between sympatric Dall's (137±3 kHz and Canadian harbour porpoises (141±2 kHz. Danish harbour porpoise clicks (136±3 kHz were more similar to Dall's porpoise than to their conspecifics in Canada. We suggest that the spectral differences in echolocation clicks between the sympatric porpoises are consistent with evolution of a prezygotic isolating barrier (i.e., character displacement to avoid hybridization of sympatric species. In practical terms, these spectral differences have immediate application to passive acoustic monitoring.

  16. Using narrow-band imaging with conventional hysteroscopy increases the detection of chronic endometritis in abnormal uterine bleeding and postmenopausal bleeding.

    Ozturk, Mustafa; Ulubay, Mustafa; Alanbay, Ibrahim; Keskin, Uğur; Karasahin, Emre; Yenen, Müfit Cemal

    2016-01-01

    A preliminary study was designed to evaluate whether a narrow-band imaging (NBI) endoscopic light source could detect chronic endometritis that was not identifiable with a white light hysteroscope. A total of 86 patients with endometrial pathology (71 abnormal uterine bleeding and 15 postmenopausal bleeding) were examined by NBI endoscopy and white light hysteroscopy between February 2010 and February 2011. The surgeon initially observed the uterine cavity using white light hysteroscopy and made a diagnostic impression, which was recorded. Subsequently, after pressing a button on the telescope, NBI was used to reevaluate the endometrial mucosa. The median age of the patients was 40 years (range: 30-60 years). Endometritis was diagnosed histologically. Six cases of abnormal uterine bleeding (6/71, 8.4%, 95% confidence interval [CI] 0.03-0.17) and one case of postmenopausal bleeding (1/15, 6%, 95%CI 0.01-0.29) were only diagnosed with chronic endometritis by NBI (7/86, 8.1%, 95%CI 0.04-0.15). Capillary patterns of the endometrium can be observed by NBI and this method can be used to assess chronic endometritis. © 2015 Japan Society of Obstetrics and Gynecology.

  17. Prediction of Helicobacter pylori status by conventional endoscopy, narrow-band imaging magnifying endoscopy in stomach after endoscopic resection of gastric cancer.

    Yagi, Kazuyoshi; Saka, Akiko; Nozawa, Yujiro; Nakamura, Atsuo

    2014-04-01

    To reduce the incidence of metachronous gastric carcinoma after endoscopic resection of early gastric cancer, Helicobacter pylori eradication therapy has been endorsed. It is not unusual for such patients to be H. pylori negative after eradication or for other reasons. If it were possible to predict H. pylori status using endoscopy alone, it would be very useful in clinical practice. To clarify the accuracy of endoscopic judgment of H. pylori status, we evaluated it in the stomach after endoscopic submucosal dissection (ESD) of gastric cancer. Fifty-six patients treated by ESD were enrolled. The diagnostic criteria for H. pylori status by conventional endoscopy and narrow-band imaging (NBI)-magnifying endoscopy were decided, and H. pylori status was judged by two endoscopists. Based on the H. pylori stool antigen test as a diagnostic gold standard, conventional endoscopy and NBI-magnifying endoscopy were compared for their sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Interobserver agreement was assessed in terms of κ value. Interobserver agreement was moderate (0.56) for conventional endoscopy and substantial (0.77) for NBI-magnifying endoscopy. The sensitivity, specificity, PPV, and NPV were 0.79, 0.52, 0.70, and 0.63 for conventional endoscopy and 0.91, 0.83, 0.88, and 0.86 for NBI-magnifying endoscopy, respectively. Prediction of H. pylori status using NBI-magnifying endoscopy is practical, and interobserver agreement is substantial. © 2013 John Wiley & Sons Ltd.

  18. Selenium, zinc, copper, Cu/Zn ratio and total antioxidant status in the serum of vitiligo patients treated by narrow-band ultraviolet-B phototherapy.

    Wacewicz, Marta; Socha, Katarzyna; Soroczyńska, Jolanta; Niczyporuk, Marek; Aleksiejczuk, Piotr; Ostrowska, Jolanta; Borawska, Maria H

    2018-03-01

    Vitiligo is a chronic, depigmenting skin disorder, whose pathogenesis is still unknown. Narrow band ultraviolet-B (NB-UVB) is now one of the most widely used treatment of vitiligo. It was suggested that trace elements may play a role in pathogenesis of vitiligo. The aim of this study was to estimate the concentration of selenium (Se), zinc (Zn), copper (Cu) and Cu/Zn ratio as well as total antioxidant status (TAS) in the serum of patients with vitiligo. We assessed 50 patients with vitiligo and 58 healthy controls. Serum levels of Se, Zn and Cu were determined by the atomic absorption spectrometry method, and the Cu/Zn ratio was also calculated. TAS in serum was measured spectrophotometrically. Serum concentration of Se in patients with vitiligo before and after phototherapy was significantly lower as compared to the control group. Zn level in the serum of patients decreased significantly after phototherapy. We observed higher Cu/Zn ratio (p vitiligo patients after NB-UVB. The current study showed some disturbances in the serum levels of trace elements and total antioxidant status in vitiligo patients.

  19. Endoscopic tri-modal imaging for detection of early neoplasia in Barrett's oesophagus: a multi-centre feasibility study using high-resolution endoscopy, autofluorescence imaging and narrow band imaging incorporated in one endoscopy system

    Curvers, W. L.; Singh, R.; Song, L.-M. Wong-Kee; Wolfsen, H. C.; Ragunath, K.; Wang, K.; Wallace, M. B.; Fockens, P.; Bergman, J. J. G. H. M.

    2008-01-01

    OBJECTIVE: To investigate the diagnostic potential of endoscopic tri-modal imaging and the relative contribution of each imaging modality (i.e. high-resolution endoscopy (HRE), autofluorescence imaging (AFI) and narrow-band imaging (NBI)) for the detection of early neoplasia in Barrett's oesophagus.

  20. Automated galaxy surface photometry

    Cawson, M.G.M.; Kibblewhite, E.J.; Disney, M.J.; Phillipps, S.

    1987-01-01

    Two-dimensional surface photometry of a very large number of galaxies on a deep Schmidt plate has been obtained using the Automatic Plate Measuring System (APM). A method of photometric calibration, suitable for APM measurements, via pixel-by-pixel comparison with CCD frames of a number of the brighter galaxies is described and its advantages are discussed. The same method is used to demonstrate the consistency of measurement of the APM machine when used for surface photometry. (author)

  1. Vascular density of superficial esophageal squamous cell carcinoma determined by direct observation of resected specimen using narrow band imaging with magnifying endoscopy.

    Kikuchi, D; Iizuka, T; Hoteya, S; Nomura, K; Kuribayashi, Y; Toba, T; Tanaka, M; Yamashita, S; Furuhata, T; Matsui, A; Mitani, T; Inoshita, N; Kaise, M

    2017-11-01

    Observation of the microvasculature using narrow band imaging (NBI) with magnifying endoscopy is useful for diagnosing superficial squamous cell carcinoma. Increased vascular density is indicative of cancer, but not many studies have reported differences between cancerous and noncancerous areas based on an objective comparison. We observed specimens of endoscopic submucosal dissection (ESD) using NBI magnification, and determined the vascular density of cancerous and noncancerous areas. A total of 25 lesions of esophageal squamous cell carcinoma that were dissected en bloc by ESD between July 2013 and December 2013 were subjected to NBI magnification. We constructed a device that holds an endoscope and precisely controls the movement along the vertical axis in order to observe submerged specimens by NBI magnification. NBI image files of both cancerous (pathologically determined invasion depth, m1/2) and surrounding noncancerous areas were created and subjected to vascular density assessment by two endoscopists who were blinded to clinical information. The invasion depth was m1/2 in 20, m3/sm1 in four and sm2 in one esophageal cancer lesion. Mean vascular density was significantly increased in cancerous areas (37.6 ± 16.3 vessels/mm2) compared with noncancerous areas (17.6 ± 10.0 vessels/mm2) (P squamous cell carcinoma. The rates of agreement between vascular density values determined by two independent operators were high. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Office-based narrow band imaging-guided flexible laryngoscopy tissue sampling: A cost-effectiveness analysis evaluating its impact on Taiwanese health insurance program.

    Fang, Tuan-Jen; Li, Hsueh-Yu; Liao, Chun-Ta; Chiang, Hui-Chen; Chen, I-How

    2015-07-01

    Narrow band imaging (NBI)-guided flexible laryngoscopy tissue sampling for laryngopharyngeal lesions is a novel technique. Patients underwent the procedure in an office-based setting without being sedated, which is different from the conventional technique performed using direct laryngoscopy. Although the feasibility and effects of this procedure were established, its financial impact on the institution and Taiwanese National Health Insurance program was not determined. This is a retrospective case-control study. From May 2010 to April 2011, 20 consecutive patients who underwent NBI flexible laryngoscopy tissue sampling were recruited. During the same period, another 20 age-, sex-, and lesion-matched cases were enrolled in the control group. The courses for procedures and financial status were analyzed and compared between groups. Office-based NBI flexible laryngoscopy tissue sampling procedure took 27 minutes to be completed, while 191 minutes were required for the conventional technique. Average reimbursement for each case was New Taiwan Dollar (NT$)1264 for patients undergoing office-based NBI flexible laryngoscopy tissue sampling, while NT$10,913 for those undergoing conventional direct laryngoscopy in the operation room (p institution suffered a loss of at least NT$690 when performing NBI flexible laryngoscopy tissue sampling. Office-based NBI flexible laryngoscopy tissue sampling is a cost-saving procedure for patients and the Taiwanese National Health Insurance program. It also saves the procedure time. However, the net financial loss for the institution and physician would limit its popularization unless reimbursement patterns are changed. Copyright © 2013. Published by Elsevier B.V.

  3. Mass measurements on neutron-deficient nuclides at SHIPTRAP and commissioning of a cryogenic narrow-band FT-ICR mass spectrometer

    Ferrer Garcia, R.

    2007-07-01

    The dissertation presented here deals with high-precision Penning trap mass spectrometry on short-lived radionuclides. Owed to the ability of revealing all nucleonic interactions, mass measurements far off the line of {beta}-stability are expected to bring new insight to the current knowledge of nuclear properties and serve to test the predictive power of mass models and formulas. In nuclear astrophysics, atomic masses are fundamental parameters for the understanding of the synthesis of nuclei in the stellar environments. This thesis presents ten mass values of radionuclides around A=90 interspersed in the predicted rp-process pathway. Six of them have been experimentally determined for the first time. The measurements have been carried out at the Penning-trap mass spectrometer SHIPTRAP using the destructive time-of-flight ion-cyclotron-resonance (TOF-ICR) detection technique. Given the limited performance of the TOF-ICR detection when trying to investigate heavy/superheavy species with small production cross sections ({sigma} <1 {mu}b), a new detection system is found to be necessary. Thus, the second part of this thesis deals with the commissioning of a cryogenic double-Penning trap system for the application of a highly-sensitive, narrow-band Fourier-transform ion-cyclotron-resonance (FT-ICR) detection technique. With the non-destructive FT-ICR detection method a single singly-charged trapped ion will provide the required information to determine its mass. First off-line tests of a new detector system based on a channeltron with an attached conversion dynode, of a cryogenic pumping barrier, to guarantee ultra-high vacuum conditions during mass determination, and of the detection electronics for the required single-ion sensitivity are reported. (orig.)

  4. The learning curve for narrow-band imaging in the diagnosis of precancerous gastric lesions by using Web-based video.

    Dias-Silva, Diogo; Pimentel-Nunes, Pedro; Magalhães, Joana; Magalhães, Ricardo; Veloso, Nuno; Ferreira, Carlos; Figueiredo, Pedro; Moutinho, Pedro; Dinis-Ribeiro, Mário

    2014-06-01

    A simplified narrow-band imaging (NBI) endoscopy classification of gastric precancerous and cancerous lesions was derived and validated in a multicenter study. This classification comes with the need for dissemination through adequate training. To address the learning curve of this classification by endoscopists with differing expertise and to assess the feasibility of a YouTube-based learning program to disseminate it. Prospective study. Five centers. Six gastroenterologists (3 trainees, 3 fully trained endoscopists [FTs]). Twenty tests provided through a Web-based program containing 10 randomly ordered NBI videos of gastric mucosa were taken. Feedback was sent 7 days after every test submission. Measures of accuracy of the NBI classification throughout the time. From the first to the last 50 videos, a learning curve was observed with a 10% increase in global accuracy, for both trainees (from 64% to 74%) and FTs (from 56% to 65%). After 200 videos, sensitivity and specificity of 80% and higher for intestinal metaplasia were observed in half the participants, and a specificity for dysplasia greater than 95%, along with a relevant likelihood ratio for a positive result of 7 to 28 and likelihood ratio for a negative result of 0.21 to 0.82, were achieved by all of the participants. No constant learning curve was observed for the identification of Helicobacter pylori gastritis and sensitivity to dysplasia. The trainees had better results in all of the parameters, except specificity for dysplasia, compared with the FTs. Globally, participants agreed that the program's structure was adequate, except on the feedback, which should have consisted of a more detailed explanation of each answer. No formal sample size estimate. A Web-based learning program could be used to teach and disseminate classifications in the endoscopy field. In this study, an NBI classification for gastric mucosal features seems to be easily learned for the identification of gastric preneoplastic

  5. Detection and recurrence rate of transurethral resection of bladder tumors by narrow-band imaging: Prospective, randomized comparison with white light cystoscopy

    Seung Bin Kim

    2018-03-01

    Full Text Available Purpose: The purpose of this study was to evaluate the efficacy of narrow-band imaging (NBI as a diagnostic tool for detecting bladder tumors during cystoscopy compared with white light cystoscopy (WLC. Materials and Methods: From December 2013 to June 2017, a randomized prospective study was conducted on 198 patients underwent transurethral resection of bladder tumor by a single surgeon. The patients were divided into two groups according to diagnostic method. In Group I, WLC only was performed. In Group II, NBI was additionally performed after WLC. We analyzed the rate of detection of bladder tumors as a primary endpoint. In addition, we evaluated rates of recurrence in each group. Results: There were no significant differences between the two groups in characteristics except hypertension. In the analysis of rates of detection, the probability of diagnosing cancer was 80.9% (114/141 in the WLC group, and the probability of diagnosing cancer using WLC in the NBI group was 85.5% (159/186. After switching from WLC to NBI for second-look cystoscopy in the NBI group, NBI was shown to detect additional tumors with a detection rate of 35.1% (13/37 from the perspective of the patients and 42.2% (27/64 from the perspective of the tumors. The 1-year recurrence-free rate was 72.2% in the WLC group and 85.2% in the NBI group (p=0.3. Conclusions: NBI had benefits for detecting tumors overlooked by WLC. Although the difference in the 1-year recurrence-free rate was not statistically significant, our results showed a trend for higher recurrence in the NBI group.

  6. Evaluation of an e-learning system for diagnosis of gastric lesions using magnifying narrow-band imaging: a multicenter randomized controlled study.

    Nakanishi, Hiroyoshi; Doyama, Hisashi; Ishikawa, Hideki; Uedo, Noriya; Gotoda, Takuji; Kato, Mototsugu; Nagao, Shigeaki; Nagami, Yasuaki; Aoyagi, Hiroyuki; Imagawa, Atsushi; Kodaira, Junichi; Mitsui, Shinya; Kobayashi, Nozomu; Muto, Manabu; Takatori, Hajime; Abe, Takashi; Tsujii, Masahiko; Watari, Jiro; Ishiyama, Shuhei; Oda, Ichiro; Ono, Hiroyuki; Kaneko, Kazuhiro; Yokoi, Chizu; Ueo, Tetsuya; Uchita, Kunihisa; Matsumoto, Kenshi; Kanesaka, Takashi; Morita, Yoshinori; Katsuki, Shinichi; Nishikawa, Jun; Inamura, Katsuhisa; Kinjo, Tetsu; Yamamoto, Katsumi; Yoshimura, Daisuke; Araki, Hiroshi; Kashida, Hiroshi; Hosokawa, Ayumu; Mori, Hirohito; Yamashita, Haruhiro; Motohashi, Osamu; Kobayashi, Kazuhiko; Hirayama, Michiaki; Kobayashi, Hiroyuki; Endo, Masaki; Yamano, Hiroo; Murakami, Kazunari; Koike, Tomoyuki; Hirasawa, Kingo; Miyaoka, Youichi; Hamamoto, Hidetaka; Hikichi, Takuto; Hanabata, Norihiro; Shimoda, Ryo; Hori, Shinichiro; Sato, Tadashi; Kodashima, Shinya; Okada, Hiroyuki; Mannami, Tomohiko; Yamamoto, Shojiro; Niwa, Yasumasa; Yashima, Kazuo; Tanabe, Satoshi; Satoh, Hiro; Sasaki, Fumisato; Yamazato, Tetsuro; Ikeda, Yoshiou; Nishisaki, Hogara; Nakagawa, Masahiro; Matsuda, Akio; Tamura, Fumio; Nishiyama, Hitoshi; Arita, Keiko; Kawasaki, Keisuke; Hoppo, Kazushige; Oka, Masashi; Ishihara, Shinichi; Mukasa, Michita; Minamino, Hiroaki; Yao, Kenshi

    2017-10-01

    Background and study aim  Magnifying narrow-band imaging (M-NBI) is useful for the accurate diagnosis of early gastric cancer (EGC). However, acquiring skill at M-NBI diagnosis takes substantial effort. An Internet-based e-learning system to teach endoscopic diagnosis of EGC using M-NBI has been developed. This study evaluated its effectiveness. Participants and methods  This study was designed as a multicenter randomized controlled trial. We recruited endoscopists as participants from all over Japan. After completing Test 1, which consisted of M-NBI images of 40 gastric lesions, participants were randomly assigned to the e-learning or non-e-learning groups. Only the e-learning group was allowed to access the e-learning system. After the e-learning period, both groups received Test 2. The analysis set was participants who scored e-learning group and 197 in the non-e-learning group). After the e-learning period, all 395 completed Test 2. The analysis sets were e-learning group: n = 184; and non-e-learning group: n = 184. The mean Test 1 score was 59.9 % for the e-learning group and 61.7 % for the non-e-learning group. The change in accuracy in Test 2 was significantly higher in the e-learning group than in the non-e-learning group (7.4 points vs. 0.14 points, respectively; P  e-learning system in improving practitioners' capabilities to diagnose EGC using M-NBI.Trial registered at University Hospital Medical Information Network Clinical Trials Registry (UMIN000008569). © Georg Thieme Verlag KG Stuttgart · New York.

  7. An alternative option for "resect and discard" strategy, using magnifying narrow-band imaging: a prospective "proof-of-principle" study.

    Takeuchi, Yoji; Hanafusa, Masao; Kanzaki, Hiromitsu; Ohta, Takashi; Hanaoka, Noboru; Yamamoto, Sachiko; Higashino, Koji; Tomita, Yasuhiko; Uedo, Noriya; Ishihara, Ryu; Iishi, Hiroyasu

    2015-10-01

    The "resect and discard" strategy is beneficial for cost savings on screening and surveillance colonoscopy, but it has the risk to discard lesions with advanced histology or small invasive cancer (small advanced lesion; SALs). The aim of this study was to prove the principle of new "resect and discard" strategy with consideration for SALs using magnifying narrow-band imaging (M-NBI). Patients undergoing colonoscopy at a tertiary center were involved in this prospective trial. For each detected polyp <10 mm, optical diagnosis (OD) and virtual management ("leave in situ", "discard" or "send for pathology") were independently made using non-magnifying NBI (N-NBI) and M-NBI, and next surveillance interval were predicted. Histological and optical diagnosis results of all polyps were compared. While the management could be decided in 82% of polyps smaller than 10 mm, 24/31 (77%) SALs including two small invasive cancers were not discarded based on OD using M-NBI. The sensitivity [90% confidence interval (CI)] of M-NBI for SALs was 0.77 (0.61-0.89). The risk for discarding SALs using N-NBI was significantly higher than that using M-NBI (53 vs. 23%, p = 0.02). The diagnostic accuracy (95% CI) of M-NBI in distinguishing neoplastic from non-neoplastic lesions [0.88 (0.86-0.90)] was significantly better than that of N-NBI [0.84 (0.82-0.87)] (p = 0.005). The results of our study indicated that our "resect and discard" strategy using M-NBI could work to reduce the risk for discarding SALs including small invasive cancer (UMIN-CTR, UMIN000003740).

  8. Comparison of high-resolution magnification narrow-band imaging and white-light endoscopy in the prediction of histology in Barrett's oesophagus.

    Singh, Rajvinder; Karageorgiou, Haris; Owen, Victoria; Garsed, Klara; Fortun, Paul J; Fogden, Edward; Subramaniam, Venkataraman; Shonde, Anthony; Kaye, Philip; Hawkey, Christopher J; Ragunath, Krish

    2009-01-01

    To evaluate whether there is any appreciable difference in imaging characteristics between high-resolution magnification white-light endoscopy (WLE-Z) and narrow-band imaging (NBI-Z) in Barrett's oesophagus (BE) and if this translates into superior prediction of histology. This was a prospective single-centre study involving 21 patients (75 areas, corresponding NBI-Z and WLE-Z images) with BE. Mucosal patterns (pit pattern and microvascular morphology) were evaluated for their image quality on a visual analogue scale (VAS) of 1-10 by five expert endoscopists. The endoscopists then predicted mucosal morphology based on four subtypes which can be visualized in BE. Type A: round pits, regular microvasculature; type B: villous/ridge pits, regular microvasculature; type C: absent pits, regular microvasculature; type D: distorted pits, irregular microvasculature. The sensitivity (Sn), specificity (Sp), positive predictive value (PPV), negative predictive value (NPV) and accuracy (Acc) were then compared with the final histopathological analysis and the interobserver variability calculated. The overall pit and microvasculature quality was significantly higher for NBI-Z, pit: NBI-Z=6, WLE-Z=4.5, p < 0.001; microvasculature: NBI-Z=7.3, WLE-Z=4.9, p < 0.001. This translated into a superior prediction of histology (Sn: NBI-Z: 88.9, WLE-Z: 71.9, p < 0.001). For the prediction of dysplasia, NBI-Z was superior to WLE-Z (chi(2)=10.3, p < 0.05). The overall kappa agreement among the five endoscopists for NBI-Z and WLE-Z, respectively, was 0.59 and 0.31 (p < 0.001). NBI-Z is superior to WLE-Z in the prediction of histology in BE, with good reproducibility. This novel imaging modality could be an important tool for surveillance of patients with BE.

  9. GROUND-BASED Paα NARROW-BAND IMAGING OF LOCAL LUMINOUS INFRARED GALAXIES. I. STAR FORMATION RATES AND SURFACE DENSITIES

    Tateuchi, Ken; Konishi, Masahiro; Motohara, Kentaro; Takahashi, Hidenori; Kato, Natsuko Mitani; Kitagawa, Yutaro; Todo, Soya; Toshikawa, Koji; Sako, Shigeyuki; Uchimoto, Yuka K.; Ohsawa, Ryou; Asano, Kentaro; Kamizuka, Takafumi; Nakamura, Tomohiko; Okada, Kazushi [Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ita, Yoshifusa [Astronomical Institute, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8578 (Japan); Komugi, Shinya [Division of Liberal Arts, Kogakuin University, 2665-1, Hachioji, Tokyo 192-0015 (Japan); Koshida, Shintaro [Subaru Telescope, National Astronomical Observatory of Japan, Hilo, HI 96720 (United States); Manabe, Sho [Department of Earth and Planetary Sciences, Kobe University, Kobe 657-8501 (Japan); Nakashima, Asami, E-mail: tateuchi@ioa.s.u-tokyo.ac.jp [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); and others

    2015-03-15

    Luminous infrared galaxies (LIRGs) are enshrouded by a large amount of dust produced by their active star formation, and it is difficult to measure their activity in optical wavelengths. We have carried out Paα narrow-band imaging observations of 38 nearby star forming galaxies including 33 LIRGs listed in the IRAS Revised Bright Galaxy Sample catalog with the Atacama Near InfraRed camera on the University of Tokyo Atacama Observatory (TAO) 1.0 m telescope (miniTAO). Star formation rates (SFRs) estimated from the Paα fluxes, corrected for dust extinction using the Balmer decrement method (typically A{sub V} ∼ 4.3 mag), show a good correlation with those from the bolometric infrared luminosity of the IRAS data within a scatter of 0.27 dex. This suggests that the correction of dust extinction for the Paα flux is sufficient in our sample. We measure the physical sizes and surface densities of infrared luminosities (Σ{sub L(IR)}) and the SFR (Σ{sub SFR}) of star forming regions for individual galaxies, and we find that most of the galaxies follow a sequence of local ultra-luminous or luminous infrared galaxies (U/LIRGs) on the L(IR)-Σ{sub L(IR)} and SFR-Σ{sub SFR} plane. We confirm that a transition of the sequence from normal galaxies to U/LIRGs is seen at L(IR) = 8 × 10{sup 10} L {sub ☉}. Also, we find that there is a large scatter in physical size, different from normal galaxies or ULIRGs. Considering the fact that most U/LIRGs are merging or interacting galaxies, this scatter may be caused by strong external factors or differences in their merging stages.

  10. BV photographic and CCD photometry of IC 4651

    Anthony-Twarog, B.J.; Mukherjee, K.; Twarog, B.A.; Caldwell, N.

    1988-01-01

    A BV photometric survey in IC 4651 based on photographic and CCD material calibrated with photoelectric photometry from Eggen (1971) and Anthony-Twarog and Twarog (1987) has been completed. The color-magnitude diagram is consistent with an age of 2.4 + or - 0.3 x 10 to the 9th yr derived by comparison with the isochrones of VandenBerg (1985) if the apparent distance modulus and reddening derived from uvby photometry in Anthony-Twarog and Twarog (1987) are employed. While evidence is found of a hook in the upper main sequence, no evidence is found of a significantly bifurcated main sequence for this cluster, although it is similar in age to NGC 752 and NGC 3680, where this phenomenon has been noted. Finally, the survey has not resolved the apparent deficit of main-sequence stars fainter than V = 14.5 noted in Anthony-Twarog and Twarog (1987). 16 references

  11. APT: Aperture Photometry Tool

    Laher, Russ

    2012-08-01

    Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It has a graphical user interface (GUI) which allows the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. Mouse-clicking on a source in the displayed image draws a circular or elliptical aperture and sky annulus around the source and computes the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs, including image histogram, and aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has functions for customizing calculations, including outlier rejection, pixel “picking” and “zapping,” and a selection of source and sky models. The radial-profile-interpolation source model, accessed via the radial-profile-plot panel, allows recovery of source intensity from pixels with missing data and can be especially beneficial in crowded fields.

  12. Comparative Study of the Gross Interpretation of Phototesting and Objective Measurement with Using a Spectrophotometer for Patients with Psoriasis and Vitiligo Treated with Narrow-band UVB.

    Choi, Kyu-Won; Kim, Ki-Ho; Kim, Young-Hun

    2009-05-01

    Determination of the minimal erythema dose (MED) is important for developing a phototherapy protocol and to diagnosis photosensitivity disorders. But obtaining a precise and reproducible MED is quite difficult because a phototest for erythema is based on subjective assessment. The objective of our study was to compare the gross interpretation of a phototest and the objective measurement using a spectrophotometer for determining the parameters of cutaneous narrow-band UVB (NBUVB) therapy. A total of 14 psoriasis and 10 vitiligo patients who receiving NBUVB phototherapy with skin types III and IV were selected for this study. To perform phototesting, ten sites on the skin of the back were vertically exposed to a series of 10 NBUVB doses among 14 doses between 340 and 1,400 mJ/cm(2). We interpreted the gross findings of erythema and measured the L*a*b* values with using a spectrophotometer at each phototest spot and at the control skin. Also, we evaluate the relationship between the gross presentation and the spectrophotometric analysis by delta E for the assessment of the minimal perceptible erythema (MPE) and MED. For all the subjects, the MEDs were measured in the 490~1,000 mJ/cm(2) range. The average of the colorimetric values for the control skin were L*: 64.8, a*: 7.9 and b*: 19.8. Among them, the L* value and MED value were shown to be inversely correlated, and as the L* value was decreased, the MED was increased. For the MPE, the delta E, which was the color difference of the normal skin and the phototest area, was within the range of 1.5~3.0 in 17 of the 21 patients, and 4 patients were within the range of 1.0~1.5. For the MED, among the 21 patients, the delta E of 17 patients was within the range of 3.0~6.0, and 4 patients were within the range of 6.0~12.0. A spectrophotometer enables UV erythema to be assessed objectively and quantitatively, and this can compensate for the disadvantages of subjective gross interpretation when determining the MED. Delta E is

  13. DETECTIONS OF LYMAN CONTINUUM FROM STAR-FORMING GALAXIES AT z ∼ 3 THROUGH SUBARU/SUPRIME-CAM NARROW-BAND IMAGING

    Iwata, I.; Inoue, A. K.; Matsuda, Y.; Furusawa, H.; Akiyama, M.; Hayashino, T.; Kousai, K.; Yamada, T.; Burgarella, D.; Deharveng, J.-M.

    2009-01-01

    Knowing the amount of ionizing photons from young star-forming galaxies is of particular importance to understanding the reionization process. Here we report initial results of a Subaru/Suprime-Cam deep imaging observation of the SSA22 proto-cluster region at z = 3.09, using a special narrow-band filter to optimally trace ionizing radiation from galaxies at z ∼ 3. The unique wide field-of-view of Suprime-Cam enabled us to search for ionizing photons from 198 galaxies (73 Lyman break galaxies (LBGs) and 125 Lyα emitters (LAEs)) with spectroscopically measured redshifts z ≅ 3.1. We detected ionizing radiation from 7 LBGs, as well as from 10 LAE candidates. Some of the detected galaxies show significant spatial offsets of ionizing radiation from nonionizing UV emission. For some LBGs the observed nonionizing UV to Lyman continuum flux density ratios are smaller than values expected from population synthesis models with a standard Salpeter initial mass function (IMF) with moderate dust attenuation (which is suggested from the observed UV slopes), even if we assume very transparent intergalactic medium along the sightlines of these objects. This implies an intrinsically bluer spectral energy distribution, e.g., that produced by a top-heavy IMF, for these LBGs. The observed flux density ratios of nonionizing UV to ionizing radiation of 7 detected LBGs range from 2.4 to 23.8 and the median is 6.6. The observed flux density ratios of the detected LAEs are even smaller than LBGs, if they are truly at z ≅ 3.1. We find that the median value of the flux density ratio for the detected LBGs suggests that their escape fractions are likely to be higher than 4%, if the Lyman continuum escape is isotropic. The results imply that some of the LBGs in the proto-cluster at z ∼ 3 have escape fraction significantly higher than that of galaxies (in a general field) at z ∼ 1 studied previously.

  14. Stellar photometry and polarimetry

    Golay, M.; Serkowski, K.

    1976-01-01

    A critical review of progress made in stellar photometry and polarimetry over the period 1973-1975 is presented. Reports of photometric measurements from various observatories throughout the world are summarized. The summary of work on stellar polarimetry lists the review papers, the catalogues and lists of standard stars, and descriptions of new observing techniques. (B.R.H.)

  15. Aperture Photometry Tool

    Laher, Russ R.; Gorjian, Varoujan; Rebull, Luisa M.; Masci, Frank J.; Fowler, John W.; Helou, George; Kulkarni, Shrinivas R.; Law, Nicholas M.

    2012-07-01

    Aperture Photometry Tool (APT) is software for astronomers and students interested in manually exploring the photometric qualities of astronomical images. It is a graphical user interface (GUI) designed to allow the image data associated with aperture photometry calculations for point and extended sources to be visualized and, therefore, more effectively analyzed. The finely tuned layout of the GUI, along with judicious use of color-coding and alerting, is intended to give maximal user utility and convenience. Simply mouse-clicking on a source in the displayed image will instantly draw a circular or elliptical aperture and sky annulus around the source and will compute the source intensity and its uncertainty, along with several commonly used measures of the local sky background and its variability. The results are displayed and can be optionally saved to an aperture-photometry-table file and plotted on graphs in various ways using functions available in the software. APT is geared toward processing sources in a small number of images and is not suitable for bulk processing a large number of images, unlike other aperture photometry packages (e.g., SExtractor). However, APT does have a convenient source-list tool that enables calculations for a large number of detections in a given image. The source-list tool can be run either in automatic mode to generate an aperture photometry table quickly or in manual mode to permit inspection and adjustment of the calculation for each individual detection. APT displays a variety of useful graphs with just the push of a button, including image histogram, x and y aperture slices, source scatter plot, sky scatter plot, sky histogram, radial profile, curve of growth, and aperture-photometry-table scatter plots and histograms. APT has many functions for customizing the calculations, including outlier rejection, pixel “picking” and “zapping,” and a selection of source and sky models. The radial-profile-interpolation source

  16. Photoelectric effect in surface-barrier structures

    Kononenko, V.K.; Tupenevich, P.A.

    1985-08-01

    Deviations from the Fowler law were observed when investigating photoelectric emission in p-type ZnTe surface-barrier structures. The revealed peculiarities of the structure photosensitivity spectrum are explained by the electron transitions involving surface states at the metal-semiconductor interface. (author)

  17. Photoelectric absorption cross sections with variable abundances

    Balucinska-Church, Monika; Mccammon, Dan

    1992-01-01

    Polynomial fit coefficients have been obtained for the energy dependences of the photoelectric absorption cross sections of 17 astrophysically important elements. These results allow the calculation of X-ray absorption in the energy range 0.03-10 keV in material with noncosmic abundances.

  18. Photometry with NICMOS

    Calzetti, D.; Dickinson, M. E.; Bergeron, L. E.; Colina, L.

    1998-12-01

    We summarize the performance of the NICMOS instrument and discuss the measured sensitivity, and the photometric performance and stability. We also present a method for removing an instrument artifact termed ``pedestal'', a bias instability that is present at a low level in most NICMOS images. The characteristics of dark frames will also be discussed, in particular as they relate to pedestal correction. NICMOS is capable of achieving the advertised performance in most areas. As an example, typical 3 sigma detection limits for a 5 orbit observation with NIC2 are 1.47 mJy arcsec(-2) in F110W, 1.67 mJy arcsec(-2) in F160W, and 12.6 mJy arcsec(-2) in F222M. The absence of time-dependent backgrounds makes infrared photometry from NICMOS highly stable, reaching an accuracy of 2% or better. NICMOS absolute calibration has been accomplished with a combination of solar analog stars and white dwarf standard stars and achieves 5% absolute photometry. An exception to these accuracies occurs for NIC3 at short wavelengths where intra-pixel sensitivity variations produces variations in relative photometry as large as 20%.

  19. ARCHANGEL: Galaxy Photometry System

    Schombert, James

    2011-07-01

    ARCHANGEL is a Unix-based package for the surface photometry of galaxies. While oriented for large angular size systems (i.e. many pixels), its tools can be applied to any imaging data of any size. The package core contains routines to perform the following critical galaxy photometry functions: sky determination; frame cleaning; ellipse fitting; profile fitting; and total and isophotal magnitudes. The goal of the package is to provide an automated, assembly-line type of reduction system for galaxy photometry of space-based or ground-based imaging data. The procedures outlined in the documentation are flux independent, thus, these routines can be used for non-optical data as well as typical imaging datasets. ARCHANGEL has been tested on several current OS's (RedHat Linux, Ubuntu Linux, Solaris, Mac OS X). A tarball for installation is available at the download page. The main routines are Python and FORTRAN based, therefore, a current installation of Python and a FORTRAN compiler are required. The ARCHANGEL package also contains Python hooks to the PGPLOT package, an XML processor and network tools which automatically link to data archives (i.e. NED, HST, 2MASS, etc) to download images in a non-interactive manner.

  20. Monolithic all-PM femtosecond Yb-fiber laser stabilized with a narrow-band fiber Bragg grating and pulse-compressed in a hollow-core photonic crystal fiber

    Turchinovich, Dmitry; Liu, Xiaomin; Lægsgaard, Jesper

    2008-01-01

    . The laser output is compressed in a spliced-on hollow-core PM photonic crystal fiber, thus providing direct end-of-the-fiber delivery of pulses of around 370 fs duration and 4 nJ energy with high mode quality. Tuning the pump power of the end amplifier of the laser allows for the control of output pulse......We report on an environmentally stable self-starting monolithic (i.e. without any free-space coupling) all-polarization-maintaining (PM) femtosecond Yb-fiber laser, stabilized against Q-switching by a narrow-band fiber Bragg grating and modelocked using a semiconductor saturable absorber mirror...

  1. Photoelectric panel with equatorial mounting of drive

    Kukhta, M. S.; Krauinsh, P. Y.; Krauinsh, D. P.; Sokolov, A. P.; Mainy, S. B.

    2018-03-01

    The relevance of the work is determined by the need to create effective models for sunny energy. The article considers a photoelectric panel equipped with a system for tracking the sun. Efficiency of the system is provided by equatorial mounting, which compensates for the rotation of the Earth by rotating the sunny panel in the plane of the celestial equator. The specificity of climatic and geographical conditions of Tomsk is estimated. The dynamics of power variations of photoelectric panels with equatorial mounting during seasonal fluctuations in Tomsk is calculated. A mobile photovoltaic panel with equatorial mounting of the drive has been developed. The methods of design strategy for placing photovoltaic panels in the architectural environment of the city are presented. Key words: sunny energy, photovoltaics, equatorial mounting, mechatronic model, wave reducer, electric drive.

  2. Photoelectric properties of ZnO/Ag2S heterostructure and its photoelectric ethanol sensing characteristics

    Zhang Yu; Liu Bingkun; Wang Dejun; Lin Yanhong; Xie Tengfeng; Zhai Jiali

    2012-01-01

    Highlights: ► The ZnO/Ag 2 S heterostructure shows good photoelectric properties under visible-light irradiation. ► Transient photovoltage results reveal the separation process of photo-generated charges and give further evidence of interfacial effects. ► Photoelectric ethanol sensing characteristics have been found for the ZnO/Ag 2 S heterostructure at room temperature. - Abstract: The photoelectric properties of ZnO microspheres, ZnO/Ag 2 S heterogeneous microspheres and Ag 2 S hollow microspheres were investigated systematically by surface photovoltage, transient photovoltage and surface photocurrent techniques. The ZnO/Ag 2 S heterostructure shows superior photoelectric properties in visible-light region compared with pure Ag 2 S. Transient photovoltage results reveal the separation processes of photo-generated charge carriers in the samples. The photoelectric ethanol sensing property induced by visible light for the ZnO/Ag 2 S heterostructure has been found, which should be valuable for the practical application of semiconductor gas sensors at room temperature.

  3. UBVRI photometry in NGC6791

    Brogaard, K.; Vandenberg, D. A.; Bruntt, H.

    2012-01-01

    New reduction of photometric B, V, I observations from Stetson et al. (2003, Cat. J/PASP/115/413) with updated photometry zero-points according to Stetson et al. (2005PASP..117..563S), and the same photometry, but empirically corrected for differential reddening using the procedure described in M...

  4. Electronographic photometry of star clusters in the Magellanic Clouds

    Walker, M.F.

    1979-01-01

    Electronographic magnitudes and colours of 78 stars in the cluster Hodge 11 in the Large Magellanic Cloud have been measured to V = 21.5 on electrographs taken with a Spectracon image-converter attached to the focus of the 1.5-m (60-inch) Cerro Tololo reflector. The zero point of the electronographic photometry was provided by photoelectric observations of four stars in the cluster field using the same telescope. The colour-magnitude diagram of the cluster consists of an evolved main sequence, whose termination point corresponds to an age of about 6 x 10 8 yr, but with a giant branch which is displaced blueward by about Δ(B-V) 0 = 0.4 from the positions of the giant branches of open clusters of similar age in our Galaxy. (author)

  5. SCIENCE OF SUN PHOTOMETRY

    Alexandru Dan Toma

    2013-07-01

    Full Text Available Typically, the total amount of gases and particles in a column of atmosphere cannot be determined from measurements just at Earth's surface, by a single measurement essentially at the bottom of the atmosphere column. Balloons, airplanes, and rockets are all used to perform direct measurements in the atmosphere at altitudes up to and beyond the stratosphere. Satellite-based instruments provide global views, but it is difficult to infer surface and column distributions from space-based measurements, so such measurements must still be supplemented by ground-based measurements. Sun photometry is an important way of probing the atmosphere from the ground to measure the effects of the atmosphere on Sun radiation crossing through the atmosphere to Earth's surface. These indirect technique provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly close to Earth's surface.

  6. Evidence of vectorial photoelectric effect on Copper

    Pedersoli, E.; Banfi, F.; Ressel, B.; Pagliara, S.; Giannetti, C.; Galimberti, G.; Lidia, S.; Corlett, J.; Ferrini, G.; Parmigiani, F.

    2005-01-01

    Quantum efficiency (QE) measurements of single photon photoemission from a Cu(111) single crystal and a Cu polycrystal photocathodes, irradiated by 150 fs-6.28 eV laser pulses, are reported over a broad range of incidence angle, both in s and p polarizations. The maximum QE (≅4x10 -4 ) for polycrystalline Cu is obtained in p polarization at an angle of incidence θ=65 deg. . We observe a QE enhancement in p polarization which cannot be explained in terms of optical absorption, a phenomenon known as vectorial photoelectric effect. Issues concerning surface roughness and symmetry considerations are addressed. An explanation in terms of nonlocal conductivity tensor is proposed

  7. L-shell photoelectric cross section measurements

    Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1981-05-14

    L-shell photoelectric cross sections in Ta, W, Au, Pb, Th and U at 59.5 keV have been determined using three different versions of Sood's method of measuring the absolute yield of fluorescent x-rays when a target is irradiated with a known flux of photons. The results obtained by all the methods agree with one another showing that no hidden systematic errors are involved in the measurements. The present results are found to compare well with the theoretical calculations of Scofield (Lawrence Livermore Laboratory Report No 51326).

  8. Photometry of faint blue stars

    Kilkenny, D.; Hill, P.W.; Brown, A.

    1977-01-01

    Photometry on the uvby system is given for 61 faint blue stars. The stars are classified by means of the Stromgren indices, using criteria described in a previous paper (Kilkenny and Hill (1975)). (author)

  9. Production of events with two or three muons in the final state during the interaction on nucleons of neutrinos and anti-neutrinos of the CERN narrow band beam with a maximum energy of 200 GeV

    Maillard, Jacques.

    1979-03-01

    A study was made of the production of dimuons and trimuons in the neutrino interactions using the data of the CDHS (CERN-Dortmund-Heidelberg-Saclay Cooperation) experiment taken in the CERN narrow band beam. The analysis of the quick results (since the statistics are weak) leads to significant conclusions on these events: 1) the c quark fragmentation function is approximately flat, 2) the production of heavy leptons, if this exists, only represents a very small part of the charged currents (10 -4 approximately). 3) the pair production of charmed quarks can explain some of the dimuons of same sign, the greater part of these events coming from the semi leptonic disintegration of pions and kaons (π→μν,K → μν) produced in the hadronic jet. 4) any other process (for instance the production of b quarks) is very weak ( -3 of the charged currents) [fr

  10. The GO Cygni system: photoelectric observations and light curves analysis

    Rovithis, P.; Rovithis-Livaniou, H.; Niarchos, P.G.

    1990-01-01

    Photoelectric observations, in B and V, of the system GO Cygni obtained during 1985 at the Kryonerion Astronomical Station of the National Observatory of Greece are given. The corresponding light curves (typical β Lyrae) are analysed using Frequency Domain techniques. New photoelectric and absolute elements for the system are given, and its period was found to continue its increasing

  11. Stromvil Photometry of Clusters II. The Open Cluster M67

    Boyle, R. P.; Philip, A. G. D.; Straižys, V.

    1998-12-01

    Use of the Stromgren four-color photometric system with the addition of three filters (P, Z, S) of the Vilnius system allows classifying all the types of stars, even in the presence of significant reddening by interstellar dust (Strai\\v{z}ys et al, 1996). With this Stromvil system we have begun a long-term observational program on the Vatican Advanced Technology Telescope (VATT) on Mt. Graham, Arizona, (see Philip et al,1996). The Loral 2K by 2K CCD, prepared by M. Lesser of the University of Arizona CCD Lab, gives as high as 90% quantum efficiency in most of the filters and notably 65% at the u filter. To demonstrate the degree of success so far attained in this CCD Stromvil System, we present preliminary results on the open cluster M67. We will compare some of our photometry with the CCD results of B. A. Twarog (1987) and the photoelectric photometry of Nissen et al. (1987). REFERENCES Nissen, P.E., Twarog, B.A., and Crawford, D.L. 1987, A.J. 93,634 Philip, A.G. Davis, Boyle, R.P., Strai\\v{z}ys, V. 1996, Baltic Astronomy,5,445 Strai\\v{z}ys, V., Crawford, D.L., Philip, A.G.Davis 1996, Baltic Astronomy, 5,83 Twarog, B.A. 1987, A.J. 93,647

  12. CCD photometry in the Vilnius photometric systems. II. Analysis of a region in Lyra

    Smriglio, F.; Dasgupta, A.K.; Boyle, R.P.; Straizys, V.; Janulis, R.

    1991-01-01

    Two-dimensional classification of 216 stars down to 17 mag based on their seven color photoelectric and CCD photometry in the Vilnius system is presented. Except for normal stars, several subdwarfs, metal-deficient giants, and stars of other peculiarities are suspected. Interstellar extinction is determined for normal stars in two areas north and south of globular cluster M56, as well as for a 1 square degree area around M56. The mean value of A v outside the galactic dust layer is ∼ 0.75 mag

  13. CCD photometry in the Vilnius photometric systems. II. Analysis of a region in Lyra

    Smriglio, F.; Dasgupta, A.K. (Rome Univ. (IT). Ist. Astronomico); Nandy, K. (Royal Observatory, Edinburgh (UK)); Boyle, R.P. (Vatican Observatory, Rome (IT)); Straizys, V.; Janulis, R. (AN Litovskoj SSR, Vilnius (SU). Inst. Fiziki)

    1991-04-01

    Two-dimensional classification of 216 stars down to 17 mag based on their seven color photoelectric and CCD photometry in the Vilnius system is presented. Except for normal stars, several subdwarfs, metal-deficient giants, and stars of other peculiarities are suspected. Interstellar extinction is determined for normal stars in two areas north and south of globular cluster M56, as well as for a 1 square degree area around M56. The mean value of A{sub v} outside the galactic dust layer is {similar to} 0.75 mag.

  14. Stroemgren and BV photometry of potential halo blue horizontal branch field stars

    Flynn, C; Sommer-Larsen, J

    1988-11-01

    Stroemgren four-colour and broadband BV photoelectric photometry has been obtained for a sample of potential halo blue horizontal branch stars in two high galactic latitude fields. The large majority of the stars observed are classified as blue horizontal branch stars on the basis of two different surface gravity indicators. Measurements of Ca K-line equivalent widths from medium-dispersion spectra of the stars confirm that most are Population II objects. No metal-rich A-stars were found beyond a few kpc from the galactic disc in the study of faint blue stars.

  15. Photoelectrically automated, bakeable, high-load ultramicrobalance

    Czanderna, A.W.; Kollen, W.; Biegen, J.R.; Rodder, J.

    1976-01-01

    An all quartz pivotal-beam ultramicrobalance has been modified for operation as a null instrument using a dual-path photoelectric detector. The beam and newly designed stainless steel beam support have been adapted to a stainless steel enclosure for studies in uhv. A thin quartz disk, with a 600-A thick Au film for partially blocking the light path, is fused to each end of the beam. An electronic circuit minimizes the signal from the detector when the balance moves from the null by providing a current output to a magnetic compensation coil. The capacity (up to 20 g), the stability of the null reading (over six months), and the unusually high load to precision ratio (1--2x10 8 ) of the balance have been maintained with the modification. Sensibilities of 0.03--0.1 μg with 4--10-g loads have been obtained with the balance, which is now completely adapted for UHV operation

  16. Combined effects of blue light and supplemental far-red light and effects of increasing red light with constant far-red light on growth of kidney bean [Phaseolus vulgaris] under mixtures of narrow-band light sources

    Hanyu, H.; Shoji, K.

    2000-01-01

    Increasing blue light and decreasing R: FR with supplementary far-red light affect morphogenesis, dry matter production and dry matter partitioning to leaves, stems and roots. In this study, the combined effects of the two spectral treatments were examined in kidney bean (Phaseolus vulgaris L.) grown under the mixture of four different narrow-band light sources. In addition, because the leaf and stem growth are accelerated by increasing red light (600-700 nm) in proportion to far-red light (700-800 nm) while keeping R : FR constant, this study was conducted to determine whether red light or far-red light causes the acceleration of growth. Increasing blue light (400-500 nm) and decreasing R : FR only interacted on stem extension. The results illustrated with figures suggest that blue light amplifies or attenuates the acceleration of stem extension caused by decreasing R : FR. On the other hand, increasing red light with constant far-red light had no influence on leaf expansion or stem extension while R : FR increased. Because the acceleration of leaf and stem growth is caused by increasing either far-red light or both red and far-red light in our environmental conditions, the stimulative effects on leaves and stems seem to require increases in far-red light rather than red light

  17. The add-on N-acetylcysteine is more effective than dimethicone alone to eliminate mucus during narrow-band imaging endoscopy: a double-blind, randomized controlled trial.

    Chen, Ming-Jen; Wang, Horng-Yuan; Chang, Chen-Wang; Hu, Kuang-Chun; Hung, Chien-Yuan; Chen, Chih-Jen; Shih, Shou-Chuan

    2013-02-01

    Recent studies have shown that pronase can improve mucosal visibility, but this agent is not uniformly available for human use worldwide. This study aimed to assess the efficacy of N-acetylcysteine (NAC), a mucolytic agent, in improving mucus elimination as measured by decreased endoscopic water flushes during narrow-band imaging (NBI) endoscopy. A consecutive series of patients scheduled for upper gastrointestinal endoscopy at outpatient clinics were enrolled in this double-blind, randomized controlled trial. The control group drank a preparation of 100 mg dimethicone (5 ml at 20 mg/ml) plus water up to 100 ml, and the NAC group drank 300 mg NAC plus 100 mg dimethicone and water up to 100 ml. During the endoscopy, the endoscopist used as many flushes of water as deemed necessary to produce a satisfactory NBI view of the entire gastric mucosa. In all, 177 patients with a mean age of 51 years were evaluated in this study. Significantly lesser water was used for flushing during NBI endoscopy for the NAC group than the control group; 40 ml (30-70, 0-120) versus 50 ml (30-100, 0-150) (median (interquartile range, range), p = 0.0095). Considering the safety profile of NAC, decreasing the number of water flushes for optimal vision and unavailability of pronase in some areas, the authors suggest the use of add-on NAC to eliminate mucus during NBI endoscopy.

  18. A randomized clinical trial in vitamin D-deficient adults comparing replenishment with oral vitamin D3 with narrow-band UV type B light: effects on cholesterol and the transcriptional profiles of skin and blood.

    Ponda, Manish P; Liang, Yupu; Kim, Jaehwan; Hutt, Richard; Dowd, Kathleen; Gilleaudeau, Patricia; Sullivan-Whalen, Mary M; Rodrick, Tori; Kim, Dong Joo; Barash, Irina; Lowes, Michelle A; Breslow, Jan L

    2017-05-01

    Background: Vitamin D deficiency, defined as a serum 25-hydroxyvitamin D [25(OH)D] concentration light. Objective: We tested the hypothesis that, in vitamin D-deficient adults, the replenishment of vitamin D with UVB exposure would lower LDL-cholesterol concentrations compared with the effect of oral vitamin D 3 supplementation. Design: We performed a randomized clinical trial in vitamin D-deficient adults and compared vitamin D replenishment between subjects who received oral vitamin D 3 ( n = 60) and those who received narrow-band UVB exposure ( n = 58) ≤6 mo. Results: There was no difference in the change from baseline LDL-cholesterol concentrations between oral vitamin D 3 and UVB groups (difference in median of oral vitamin D 3 minus that of UVB: 1.5 mg/dL; 95% CI: -5.0, 7.0 mg/dL). There were also no differences within groups or between groups for changes in total or HDL cholesterol or triglycerides. Transcriptional profiling of skin and blood, however, revealed significant upregulation of immune pathway signaling with oral vitamin D 3 but significant downregulation with UVB. Conclusions: Correcting vitamin D deficiency with either oral vitamin D 3 or UVB does not improve the lipid profile. Beyond cholesterol, these 2 modalities of raising 25(OH)D have disparate effects on gene transcription. This trial was registered at clinicaltrials.gov as NCT01688102. © 2017 American Society for Nutrition.

  19. RF Photoelectric injectors using needle cathodes

    Lewellen, J.W.; Brau, C.A.

    2003-01-01

    Photocathode RF guns, in various configurations, are the injectors of choice for both current and future applications requiring high-brightness electron beams. Many of these applications, such as single-pass free-electron lasers, require beams with high brilliance but not necessarily high charge per bunch. Field-enhanced photoelectric emission has demonstrated electron-beam current density as high as 10 10 A/m 2 , with a quantum efficiency in the UV that approaches 10% at fields on the order of 10 10 V/m. Thus, the use of even a blunt needle holds promise for increasing cathode quantum efficiency without sacrificing robustness. We present an initial study on the use of needle cathodes in photoinjectors to enhance beam brightness while reducing beam charge. Benefits include lower drive-laser power requirements, easier multibunch operation, lower emittance, and lower beam degradation due to charge-dependent effects in the postinjector accelerator. These benefits result from a combination of a smaller cathode emission area, greatly enhanced RF field strength at the cathode, and the charge scaling of detrimental postinjector linac effects, e.g., transverse wakefields and CSR

  20. RF Photoelectric injectors using needle cathodes

    Lewellen, J. W.; Brau, C. A.

    2003-07-01

    Photocathode RF guns, in various configurations, are the injectors of choice for both current and future applications requiring high-brightness electron beams. Many of these applications, such as single-pass free-electron lasers, require beams with high brilliance but not necessarily high charge per bunch. Field-enhanced photoelectric emission has demonstrated electron-beam current density as high as 10 10 A/m 2, with a quantum efficiency in the UV that approaches 10% at fields on the order of 10 10 V/m. Thus, the use of even a blunt needle holds promise for increasing cathode quantum efficiency without sacrificing robustness. We present an initial study on the use of needle cathodes in photoinjectors to enhance beam brightness while reducing beam charge. Benefits include lower drive-laser power requirements, easier multibunch operation, lower emittance, and lower beam degradation due to charge-dependent effects in the postinjector accelerator. These benefits result from a combination of a smaller cathode emission area, greatly enhanced RF field strength at the cathode, and the charge scaling of detrimental postinjector linac effects, e.g., transverse wakefields and CSR.

  1. Photoelectric effect photon beam position monitors

    Anon.

    1991-01-01

    Stability of the electron orbit is of critical importance at the NSLS. Many experimenters utilizing the NSLS photon beams can take full advantage of the small transverse dimensions of the source only if the electron orbit variation is kept below 10 to 20% of the transverse electron bunch size. Clearly the first step in a program to stabilize the orbit is to develop position monitors with the required sensitivity, reliability and dynamic range. Of great importance are monitors detecting the photon beams themselves, and also monitors measuring the position of the electron beam. In this section the authors discuss photon beam position monitors utilizing the photoelectric effects, and in the following section the use of capacitively coupled pick-up electrodes to detect electron beam position will be described. In what follows they shall proceed to consider two generic types of monitor geometries (1) Gap monitors, which are designed with the idea that the fringes of the synchrotron radiation will be measured, and the hot or fundamental beam will pass through the monitor unimpeded. (2) Area monitors, which are comprised of two triangular elements nested together similar to the electrodes of a split ion chamber or the diodes described by Siddons and Kraner or Mitsuhashi et al

  2. Huge operation by energy gap of novel narrow band gap Tl1-x In1-x B x Se2 (B = Si, Ge): DFT, x-ray emission and photoconductivity studies

    Piasecki, M.; Myronchuk, G. L.; Zamurueva, O. V.; Khyzhun, O. Y.; Parasyuk, O. V.; Fedorchuk, A. O.; Albassam, A.; El-Naggar, A. M.; Kityk, I. V.

    2016-02-01

    It is shown that narrow band gap semiconductors Tl1-x In1-x GexSe2 are able effectively to vary the values of the energy gap. DFT simulations of the principal bands during the cationic substitutions is done. Changes of carrier transport features is explored. Relation with the changes of the near the surface states is explored . Comparison on a common energy scale of the x-ray emission Se Kβ 2 bands, representing energy distribution of the Se 4p states, indicates that these states contribute preliminary to the top of the valence band. The temperature dependence of electrical conductivity and spectral dependence photoconductivity for the Tl1-x In1-x Ge x Se2 and Tl1-x In1-x Si x Se2 single crystals were explored and compared with previously reported Tl1-x In1-x Sn x Se2. Based on our investigations, a model of centre re-charging is proposed. Contrary to other investigated crystals in Tl1-x In1-x Ge x Se2 single crystals for x = 0.1 we observe extraordinarily enormous photoresponse, which exceed more than nine times the dark current. X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces of Tl1-x In1-x GexSe2 (x = 0.1 and 0.2) single crystals have been studied. These results indicate that the relatively low hygroscopicity of the studied single crystals is typical for the Tl1-x In1-x Ge x Se2 crystals, a property that is very important for handling these quaternary selenides as infrared materials operating at ambient conditions.

  3. Metaheuristics-Assisted Combinatorial Screening of Eu2+-Doped Ca-Sr-Ba-Li-Mg-Al-Si-Ge-N Compositional Space in Search of a Narrow-Band Green Emitting Phosphor and Density Functional Theory Calculations.

    Lee, Jin-Woong; Singh, Satendra Pal; Kim, Minseuk; Hong, Sung Un; Park, Woon Bae; Sohn, Kee-Sun

    2017-08-21

    A metaheuristics-based design would be of great help in relieving the enormous experimental burdens faced during the combinatorial screening of a huge, multidimensional search space, while providing the same effect as total enumeration. In order to tackle the high-throughput powder processing complications and to secure practical phosphors, metaheuristics, an elitism-reinforced nondominated sorting genetic algorithm (NSGA-II), was employed in this study. The NSGA-II iteration targeted two objective functions. The first was to search for a higher emission efficacy. The second was to search for narrow-band green color emissions. The NSGA-II iteration finally converged on BaLi 2 Al 2 Si 2 N 6 :Eu 2+ phosphors in the Eu 2+ -doped Ca-Sr-Ba-Li-Mg-Al-Si-Ge-N compositional search space. The BaLi 2 Al 2 Si 2 N 6 :Eu 2+ phosphor, which was synthesized with no human intervention via the assistance of NSGA-II, was a clear single phase and gave an acceptable luminescence. The BaLi 2 Al 2 Si 2 N 6 :Eu 2+ phosphor as well as all other phosphors that appeared during the NSGA-II iterations were examined in detail by employing powder X-ray diffraction-based Rietveld refinement, X-ray absorption near edge structure, density functional theory calculation, and time-resolved photoluminescence. The thermodynamic stability and the band structure plausibility were confirmed, and more importantly a novel approach to the energy transfer analysis was also introduced for BaLi 2 Al 2 Si 2 N 6 :Eu 2+ phosphors.

  4. Narrow-band emission with 0.5 to 3.5 Hz varying frequency in the background of the main phase of the 17 March 2013 magnetic storm

    Potapov A.S.

    2016-12-01

    Full Text Available We present results of the analysis of an unusually long narrow-band emission in the Pc1 range with increasing carrier frequency. The event was observed against the background of the main phase of a strong magnetic storm caused by arrival of a high-speed solar wind stream with a shock wave in the stream head and a long interval of negative vertical component of the interplanetary magnetic field. Emission of approximately 9-hour duration had a local character, appearing only at three stations located in the range of geographical longitude λ=100–130 E and magnetic shells L=2.2–3.4. The signal carrier frequency grew in a stepped mode from 0.5 to 3.5 Hz. We propose an emission interpretation based on the standard model of the generation of ion cyclotron waves in the magnetosphere due to the resonant wave-particle interaction with ion fluxes of moderate energies. We suppose that a continuous shift of the generation region, located in the outer area of the plasmasphere, to smaller L-shell is able to explain both the phenomenon locality and the range of the frequency increase. A narrow emission frequency band is associated with the formation of nose-like structures in the energy spectrum of ion fluxes penetrating from the geomagnetic tail into the magnetosphere. We offer a possible scenario of the processes leading to the generation of the observed emission. The scenario contains specific values of the generation region position, plasma density, magnetic field, and resonant proton energies. We discuss morphological differences of the emissions considered from known types of geomagnetic pulsations, and reasons for the occurrence of this unusual event.

  5. A network meta-analysis of therapeutic outcomes after new image technology-assisted transurethral resection for non-muscle invasive bladder cancer: 5-aminolaevulinic acid fluorescence vs hexylaminolevulinate fluorescence vs narrow band imaging

    Lee, Joo Yong; Cho, Kang Su; Kang, Dong Hyuk; Jung, Hae Do; Kwon, Jong Kyou; Oh, Cheol Kyu; Ham, Won Sik; Choi, Young Deuk

    2015-01-01

    This study included a network meta-analysis of evidence from randomized controlled trials (RCTs) to assess the therapeutic outcome of transurethral resection (TUR) in patients with non-muscle-invasive bladder cancer assisted by photodynamic diagnosis (PDD) employing 5-aminolaevulinic acid (5-ALA) or hexylaminolevulinate (HAL) or by narrow band imaging (NBI). Relevant RCTs were identified from electronic databases. The proceedings of relevant congresses were also searched. Fifteen articles based on RCTs were included in the analysis, and the comparisons were made by qualitative and quantitative syntheses using pairwise and network meta-analyses. Seven of 15 RCTs were at moderate risk of bias for all quality criteria and two studies were classified as having a high risk of bias. The recurrence rate of cancers resected with 5-ALA-based PDD was lower than of those resected using HAL-based PDD (odds ratio (OR) = 0.48, 95 % confidence interval (CI) [0.26–0.95]) but was not significantly different than those resected with NBI (OR = 0.53, 95 % CI [0.26–1.09]). The recurrence rate of cancers resected using HAL-based PDD versus NBI did not significantly differ (OR = 1.11, 95 % CI [0.55–2.1]). All cancers resected using 5-ALA-based PDD, HAL-based PDD, or NBI recurred at a lower rate than those resected using white light cystoscopy (WLC). No difference in progression rate was observed between cancers resected by all methods investigated. The recurrence rate of some bladder cancers can be decreased by the implementation of either PDD- and NBI-assisted TUR; in real settings, clinicians should consider replacing WLC as the standard imaging technology to guide TUR

  6. An open labeled, comparative clinical study on efficacy and tolerability of oral minipulse of steroid (OMP alone, OMP with PUVA and broad / narrow band UVB phototherapy in progressive vitiligo

    Rath Namita

    2008-01-01

    Full Text Available Background: Several modalities of treatment have been tried in vitiligo with varied results; however, Indian data on comparative studies of two or more therapies are limited. Aims: We compared different phototherapy methods with an oral steroid as an adjunct to determine the method with the best tolerability and efficacy. Methods: Eighty-six patients with progressive vitiligo were randomly assigned to different study groups according to a continuous selection method over a period of one year. Group 1 was given OMP + PUVA, group 2 OMP + UVB (NB, group 3 OMP + UVB (BB and group 4 was given OMP alone. Each patient was followed up for six months and then released from treatment. Clinical evaluation was made at the end of three and six months. Results: In group 1 (OMP + PUVA, marked improvement was seen in 18.51% while moderate improvement was seen in 66.66% of the patients. Marked improvement was seen in 37.03% in group 2 (OMP + NB-UVB while 44.44% had moderate improvement. In group 3 (OMP + BB UVB, 8.33% showed marked improvement while moderate improvement was seen in 25% of the patients. Marked and moderate improvement was seen in 5 and 10% of group 4 (OMP patients, respectively. Conclusions: Our study compared four treatment modalities in vitiligo patients, out of which oral minipulse of steroids (OMP only had an adjunct value and was not very effective by itself. Narrow band UVB has a definite edge over broad band UVB and should be preferred when both options are available. NB-UVB and PUVA showed comparable efficacy.

  7. An optimization of the FPGA/NIOS adaptive FIR filter using linear prediction to reduce narrow band RFI for the next generation ground-based ultra-high energy cosmic-ray experiment

    Szadkowski, Zbigniew, E-mail: zszadkow@kfd2.phys.uni.lodz.pl [University of Lodz, Department of Physics and Applied Informatics (Poland); Fraenkel, E.D. [Kernfysisch Versneller Instituut of the University of Groningen, Groningen (Netherlands); Glas, Dariusz; Legumina, Remigiusz [University of Lodz, Department of Physics and Applied Informatics (Poland)

    2013-12-21

    The electromagnetic part of an extensive air shower developing in the atmosphere provides significant information complementary to that obtained by water Cherenkov detectors which are predominantly sensitive to the muonic content of an air shower at ground. The emissions can be observed in the frequency band between 10 and 100 MHz. However, this frequency range is significantly contaminated by narrow-band RFI and other human-made distortions. The Auger Engineering Radio Array currently suppresses the RFI by multiple time-to-frequency domain conversions using an FFT procedure as well as by a set of manually chosen IIR notch filters in the time-domain. An alternative approach developed in this paper is an adaptive FIR filter based on linear prediction (LP). The coefficients for the linear predictor are dynamically refreshed and calculated in the virtual NIOS processor. The radio detector is an autonomous system installed on the Argentinean pampas and supplied from a solar panel. Powerful calculation capacity inside the FPGA is a factor. Power consumption versus the degree of effectiveness of the calculation inside the FPGA is a figure of merit to be minimized. Results show that the RFI contamination can be significantly suppressed by the LP FIR filter for 64 or less stages. -- Highlights: • We propose an adaptive method using linear prediction for periodic RFI suppression. • Requirements are the detection of short transient signals powered by solar panels. • The RFI is significantly suppressed by ∼70%, even in a very contaminated environment. • This method consumes less energy than the current method based on FFT used in AERA. • Distortion of the short transient signals is negligible.

  8. Real time 3D photometry

    Fernandez-Balbuena, A. A.; Vazquez-Molini, D.; García-Botella, A.; Romo, J.; Serrano, Ana

    2017-09-01

    The photometry and radiometry measurement is a well-developed field. The necessity of measuring optical systems performance involves the use of several techniques like Gonio-photometry. The Gonio photometers are a precise measurement tool that is used in the lighting area like office, luminaire head car lighting, concentrator /collimator measurement and all the designed and fabricated optical systems that works with light. There is one disadvantage in this kind of measurements that obtain the intensity polar curves and the total flux of the optical system. In the industry, there are good Gonio photometers that are precise and reliable but they are very expensive and the measurement time is long. In industry the cost can be of minor importance but measuring time that is around 30 minutes is of major importance due to trained staff cost. We have designed a system to measure photometry in real time; it consists in a curved screen to get a huge measurement angle and a CCD. The system to be measured projects light onto the screen and the CCD records a video of the screen obtaining an image of the projected profile. A complex calibration permits to trace screen data (x,y,z) to intensity polar curve (I,αγ). This intensity is obtained in candels (cd) with an image + processing time below one second.

  9. Design of Smart Multi-Functional Integrated Aviation Photoelectric Payload

    Zhang, X.

    2018-04-01

    To coordinate with the small UAV at reconnaissance mission, we've developed a smart multi-functional integrated aviation photoelectric payload. The payload weighs only 1kg, and has a two-axis stabilized platform with visible task payload, infrared task payload, laser pointers and video tracker. The photoelectric payload could complete the reconnaissance tasks above the target area (including visible and infrared). Because of its light weight, small size, full-featured, high integrated, the constraints of the UAV platform carrying the payload will be reduced a lot, which helps the payload suit for more extensive using occasions. So all users of this type of smart multi-functional integrated aviation photoelectric payload will do better works on completion of the ground to better pinpoint targets, artillery calibration, assessment of observe strike damage, customs officials and other tasks.

  10. Worldwide photometry of the January 1989 Tau Persei eclipse

    Hall, Douglas S.; Curott, David R.; Barksdale, William S.; Diethelm-Sutter, Roger; Ells, Jack

    1991-01-01

    New UBV photoelectric photometry of Tau Persei obtained at 19 different observatories during its recent January 1989 eclipse is presented. Mideclipse occurred at JD 2 447 542.31 + or - 0.01. The resulting light curve, though not complete at all phases, is solved for the elements with the help of two quantities derived from spectroscopy: the eclipse is 84 percent total at mideclipse, and the ratio of the radii is 0.135 + or - 0.01. Radii relative to the semimajor axis are 0.0236 for the G5 giant and 0.0032 for the A2 star. With a reasonable total mass assumed, the absolute radii say the A2 star could be luminosity class V or somewhat evolved and the G5 star is between III and II but could be closer to II. The G5 giant is brighter than the A2 star by 1.72 mag in V and the color excess in B - V is 0.06 mag, both quantities consistent (within uncertainties) with earlier estimates of Ake (1986). The eclipse duration, from first to fourth contact, is 2.09 day. The orbital inclination is 88.74 deg, consistent with what McAlister derived from speckle interferometry. Because of the large (e = 0.73) eccentricity, there is no secondary eclipse at all.

  11. On the Conceptual Understanding of the Photoelectric Effect

    Foong, S. K.; Lee, P.; Wong, D.; Chee, Y. P.

    2010-07-01

    We attempt an in-depth literature review that focuses on some finer aspects of the photoelectric effect that will help build a more coherent understanding of the phenomenon. These include the angular distribution of photoelectrons, multi-photon photoelectron emission and the work function in the photoelectric equation as being that associated with the collector rather than the emitter. We attempt to explain the intricacies of the related concepts in a way that is accessible to teachers and students at the Singapore GCE A-level or pre-university level.

  12. A practice course to cultivate students' comprehensive ability of photoelectricity

    Lv, Yong; Liu, Yang; Niu, Chunhui; Liu, Lishuang

    2017-08-01

    After the studying of many theoretical courses, it's important and urgent for the students from specialty of optoelectronic information science and engineering to cultivate their comprehensive ability of photoelectricity. We set up a comprehensive practice course named "Integrated Design of Optoelectronic Information System" (IDOIS) for the purpose that students can integrate their knowledge of optics, electronics and computer programming to design, install and debug an optoelectronic system with independent functions. Eight years of practice shows that this practice course can train students' ability of analysis, design/development and debugging of photoelectric system, improve their ability in document retrieval, design proposal and summary report writing, teamwork, innovation consciousness and skill.

  13. Innovation ability and innovation spirit in photoelectric comprehensive experiment teaching

    Wang, Dexing; Zhang, Yang; Wang, Xiaofeng; Zhang, Xiaojun; Zhang, Tao; Sun, Peng

    2017-08-01

    The traditional experimental teaching methods have some shortcomings in the training the student innovation ability. In order to improve the student practical ability in the photoelectric technology, in this paper new experimental teaching modes are tried and reformed for cultivating the innovative ability of students in the linear CCD experiment. The photoelectric experiment systems are independently designed and completed by students. Compared with the traditional experimental teaching methods, this new methods have a great role in the development of the ability of creative thinking.

  14. Photoelectric work function studies of carbonaceous films containing Ni nanocrystals

    Czerwosz, E.; Dluzewski, P.; Kutner, T.; Stacewicz, T.

    2003-01-01

    In this paper we present the results of photoelectric work function measurements for carbonaceous films containing Ni nanocrystals. The investigated films were obtained by thermal vacuum deposition method. The structure of films was studied by electron diffraction, transmission microscopy and Raman spectroscopy. Film structure depends on Ni contents in the film volume. Work function determined from photoelectric measurements for all investigated films are similar and lie in the range of 2.65-2.93 eV. The decrease of work function value with the cleaning of the film's surface with UV pulsed laser beam was observed

  15. 16 CFR 1211.11 - Requirements for photoelectric sensors.

    2010-01-01

    ....11 Section 1211.11 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY...) long. The obstruction is to be centered under the door perpendicular to the plane of the door when in... photoelectric sensor's beam from a position 45 degrees from the plane of the door when in the closed position...

  16. CCD photometry of NGC 2419

    Christian, C.A.; Heasley, J.N.

    1988-01-01

    The properties of the globular cluster NGC 2419 are reexamined using CCD photometry deepened to the vicinity of the main-sequence turnoff. A new color-magnitude diagram is derived that extends to V = 24.5 mag. It is concluded that NGC 2419 is an outer-halo analog of the metal-poor globulars closer to the Galactic center. NGC 2419 is probably nearly the same age as M15 and differs only slightly, if at all, in metallicity. NGC 2419 has many similarities with the clusters NGC 5466, M15, and M92. Comparison of the data with the isochrones of VandenBerg and Bell (1985) implies a distance modulus of 20.1 with Delta (B-V) = 0.18 mag. Oxygen-rich models can be fit to the data; such a comparison yields a lower limit to the acceptable distance modulus of the cluster. 26 references

  17. Distance to M33 determined from magnitude corrections to Hubble's original cepheid photometry

    Sandage, A.

    1983-01-01

    New photoelectric photometry in Selected Area 45, and transfers from a faint photoelectric sequence adjacent to the south-preceding arm in M33 have been made to the comparison stars for Hubble's Cepheids in M33. Progressive magnitude corrections are required to Hubble's M33 scales, reaching 2.8 mag at the limit of the Mount Wilson 2.5-m Hooker reflector. Hubble's Cepheid light curves have been corrected to the B photoelectric system, and new photometric parameters are given for 35 of his variables. The P-L relation agrees in zero point to within 0.2 mag of the P-L relation from independent data by Sandage and Carlson for 12 new Cepheids in an outlying region of M33. Application of an adopted absolute P-L relation, calibrated by Martin, Warren, and Feast, to these data gives an apparent blue modulus of (m-M)/sup AB//sub M33/ = 25.35, which is 0.67 mag fainter than a previously adopted value, and represents a factor of 4.2 increase of Hubble's earliest distance. Three consequences of this larger apparent distance modulus are (1) the mean absolute magnitude of the first three brightest red supergiants is M/sup max//sub left-angle-bracketV/(3)> = -8.7 rather than approx.-8.0 in M33, complicating but not destroying use of red supergiants as distance indicators, (2) the mean absolute magnitude of the two brightest blue irregular supergiant variables is M/sub left-angle-bracketB/(2)> = -9.95, which is close to the value for the brightest known supergiants in the galaxy, and (3) the absolute magnitude of M33 itself is brighter than heretofore assumed

  18. ASTROPOP: ASTROnomical Polarimetry and Photometry pipeline

    Campagnolo, Julio C. N.

    2018-05-01

    AstroPoP reduces almost any CCD photometry and image polarimetry data. For photometry reduction, the code performs source finding, aperture and PSF photometry, astrometry calibration using different automated and non-automated methods and automated source identification and magnitude calibration based on online and local catalogs. For polarimetry, the code resolves linear and circular Stokes parameters produced by image beam splitter or polarizer polarimeters. In addition to the modular functions, ready-to-use pipelines based in configuration files and header keys are also provided with the code. AstroPOP was initially developed to reduce the IAGPOL polarimeter data installed at Observatório Pico dos Dias (Brazil).

  19. Computer Simulation of Angle-measuring System of Photoelectric Theodolite

    Zeng, L; Zhao, Z W; Song, S L; Wang, L T

    2006-01-01

    In this paper, a virtual test platform based on malfunction phenomena is designed, using the methods of computer simulation and numerical mask. It is used in the simulation training of angle-measuring system of photoelectric theodolite. Actual application proves that this platform supplies good condition for technicians making deep simulation training and presents a useful approach for the establishment of other large equipment simulation platforms

  20. UBVRI photometry of variable red dwarf emission objects

    Martins, D.H.

    1974-01-01

    A review of the history and nature of small scale variability of red dwarf emission line stars is presented. This discussion is accompanied by a description of equipment developed for the purpose of expediting data acquisition for photoelectric photometry of faint stars. Data obtained at the Kitt Peak National Observatory, the Lowell Observatory, and the Rosemary Hill Observatory of the University of Florida are tabulated and analyzed to determine their implications with respect to the known variability of four stars. BY Draconis, GT Pegasus, FF Andromeda, and LP101-15 (an eclipsing binary) are studied. LP101-15 and BY Draconis were observed on the Johnson UBVRI system at Kitt Peak while BY Draconis, GT Pegasus, and FF Andromeda were observed on the Johnson RI system at the Lowell Observatory. UBV''R'' observations were carried out on all four objects at Rosemary Hill Observatory since the spring of 1972. Analysis of the data centers on discussions relative to the proposed ''spot model'' to account for the observed variations in V, R, B--V, V--R, and R--I. After allowance is made for the influence of flare activity (found to be very important), the spot model appears to be adequate in its predictions when compared with observations. A period of 0.63398 day is supported for LP101-15, and a possible secondary minimum is proposed (this secondary eclipse would be less than 0.05 magnitude deep in V), assuming the above period to be correct. This star also appears to exhibit small scale variability with a period of 0.63398 day implying synchronous rotation and revolution. Flare activity is seen to be very important on this star as well. Continued observation of these stars and similar objects is suggested, since further data are essential for complete understanding of their behavior. (U.S.)

  1. Astronomical Photometry Past, Present, and Future

    Milone, Eugene F

    2011-01-01

    This book brings together experts in the field of astronomical photometry to discuss how their subfields provide the precision and accuracy in astronomical energy flux measurements that are needed to permit tests of astrophysical theories. Differential photometers and photometry, improvements in infrared precision, the improvements in precision and accuracy of CCD photometry, the absolute calibration of flux, the development of the Johnson UBVRI photometric system and other passband systems to measure and precisely classify specific types of stars and astrophysical quantities, and the current capabilities of spectrophotometry and polarimetry to provide precise and accurate data, are all discussed in this volume. The discussion of `differential’ or `two-star’ photometers ranges from early experiments in visual photometry through the Harvard and Princeton polarizing photometers to the pioneering work of Walraven and differential photometers designed to minimize effects of atmospheric extinction and to count...

  2. Sound card based digital correlation detection of weak photoelectrical signals

    Tang Guanghui; Wang Jiangcheng

    2005-01-01

    A simple and low-cost digital correlation method is proposed to investigate weak photoelectrical signals, using a high-speed photodiode as detector, which is directly connected to a programmably triggered sound card analogue-to-digital converter and a personal computer. Two testing experiments, autocorrelation detection of weak flickering signals from a computer monitor under background of noisy outdoor stray light and cross-correlation measurement of the surface velocity of a motional tape, are performed, showing that the results are reliable and the method is easy to implement

  3. Development of Multi-Channel Photoelectric Photometer Using Optical Fiber

    Woo-Baik Lee

    1993-06-01

    Full Text Available We have developed a four-channel photoelectric photometer for the 61cm telescope of Sobaeksan Astronomy Observatory using optical fiber. We observed a standard star with each channel to check the efficiency difference between the channels, and found no differences. To calibrate the observing accuracy and efficiency, we have observed a short period WUMa type eclipsing binary star, BV Dra. Test observations show that the photometer is very stable and the accuracy of the data is also increased. The observing efficiency is very increased compared with that of single channel photometer; at least five times faster than older one in the case of one filter observation.

  4. Photoelectric elements of the eclipsing binary XY Ceti

    Srivastava, R.K.; Padalia, T.D.

    1975-01-01

    The absolute elements of the system XY Ceti have been obtained on the basis of the spectroscopic elements given by Popper (1971) and the photoelectric elements derived previously. The colours of the components have been obtained. Both components are found to lie fairly on the Main Sequence. The primary component of the system, however, is slightly more evolved as it shows a tendency to drift away from the Main Sequence. The spectral classes now assigned are A5V (primary) and A7V (secondary). The values of Roche constants indicate that the system is a detached one. (Auth.)

  5. Photoelectric radar servo control system based on ARM+FPGA

    Wu, Kaixuan; Zhang, Yue; Li, Yeqiu; Dai, Qin; Yao, Jun

    2016-01-01

    In order to get smaller, faster, and more responsive requirements of the photoelectric radar servo control system. We propose a set of core ARM + FPGA architecture servo controller. Parallel processing capability of FPGA to be used for the encoder feedback data, PWM carrier modulation, A, B code decoding processing and so on; Utilizing the advantage of imaging design in ARM Embedded systems achieves high-speed implementation of the PID algorithm. After the actual experiment, the closed-loop speed of response of the system cycles up to 2000 times/s, in the case of excellent precision turntable shaft, using a PID algorithm to achieve the servo position control with the accuracy of + -1 encoder input code. Firstly, This article carry on in-depth study of the embedded servo control system hardware to determine the ARM and FPGA chip as the main chip with systems based on a pre-measured target required to achieve performance requirements, this article based on ARM chip used Samsung S3C2440 chip of ARM7 architecture , the FPGA chip is chosen xilinx's XC3S400 . ARM and FPGA communicate by using SPI bus, the advantage of using SPI bus is saving a lot of pins for easy system upgrades required thereafter. The system gets the speed datas through the photoelectric-encoder that transports the datas to the FPGA, Then the system transmits the datas through the FPGA to ARM, transforms speed datas into the corresponding position and velocity data in a timely manner, prepares the corresponding PWM wave to control motor rotation by making comparison between the position data and the velocity data setted in advance . According to the system requirements to draw the schematics of the photoelectric radar servo control system and PCB board to produce specially. Secondly, using PID algorithm to control the servo system, the datas of speed obtained from photoelectric-encoder is calculated position data and speed data via high-speed digital PID algorithm and coordinate models. Finally, a

  6. X-Ray Spectro-Polarimetry with Photoelectric Polarimeters

    Strohmayer, T. E.

    2017-01-01

    We derive a generalization of forward fitting for X-ray spectroscopy to include linear polarization of X-ray sources, appropriate for the anticipated next generation of space-based photoelectric polarimeters. We show that the inclusion of polarization sensitivity requires joint fitting to three observed spectra, one for each of the Stokes parameters, I(E), U(E), and Q(E). The equations for StokesI (E) (the total intensity spectrum) are identical to the familiar case with no polarization sensitivity, and for which the model-predicted spectrum is obtained by a convolution of the source spectrum, F (E), with the familiar energy response function,(E) R(E,E), where (E) and R(E,E) are the effective area and energy redistribution matrix, respectively. In addition to the energy spectrum, the two new relations for U(E) and Q(E) include the source polarization fraction and position angle versus energy, a(E), and 0(E), respectively, and the model-predicted spectra for these relations are obtained by a convolution with the modulated energy response function, (E)(E) R(E,E), where(E) is the energy-dependent modulation fraction that quantifies a polarimeters angular response to 100 polarized radiation. We present results of simulations with response parameters appropriate for the proposed PRAXyS Small Explorer observatory to illustrate the procedures and methods, and we discuss some aspects of photoelectric polarimeters with relevance to understanding their calibration and operation.

  7. The Booting-Type ADRC of Airborne Photoelectrical Platform

    Xiantao Li

    2014-01-01

    Full Text Available Customary disturbance rejection in the photoelectrical platform is “passive,” which makes it difficult to further improve the isolation degree owning to the strict restriction of mechanical resonance frequency. In this paper, a booting-type ADRC is proposed, whose disturbance estimation process is guided by target value to reduce the overshoot and lag in the estimated value of disturbance. All kinds of disturbance in the system are modeled in a unified way by using the equivalent disturbance voltage to avoid the complex modeling process. Based on the simplified model, extended state observer (ESO is designed to realize a real-time estimation of the disturbance. Then, the disturbance compensation is added to generate the final control value by combining the customary square lead-lag controller. Experiments are implemented to test the proposed control strategy by mounting the photoelectrical platform on a flight simulator and generating a motion perturbation. Compared with the case of only traditional lead-lag controller, the isolation degree of disturbance is enhanced obviously. And the experiments also illustrate strong robustness of ADRC.

  8. Jonckheere Double Star Photometry - Part VII: Aquarius

    Knapp, Wilfried R. A.

    2017-10-01

    If any double star discoverer is in urgent need of photometry then it is Jonckheere. There are over 3000 Jonckheere objects listed in the WDS catalog and a good part of them with magnitudes obviously far too bright. This report covers the Jonckheere objects in the constellation Aquarius. One image per object was taken with V-filter to allow for visual magnitude measurement by differential pho-tometry. All objects were additionally checked for common proper motion by comparing 2MASS to GAIA DR1 positions and a rather surprisingly large part of the objects qualify indeed as potential CPM pairs. For a few objects also WDS position errors were found.

  9. Photoelectric conversion and electrochromic properties of lutetium tetrakis(tert-butyl)bisphthalocyaninate

    Hu, Andrew Teh; Hu Tenyi; Liu Lungchang

    2003-01-01

    Both photoelectric and electrochromic effects on lutetium tetrakis(tert-butyl)bisphthalocyaninate (Lu(TBPc) 2 ) have been carried out in this study. Lu(TBPc) 2 is known for its electrochromic performance, but its photoelectric effect has not mentioned in the literature. The electrochromic properties of Lu(TBPc) 2 have been measured by cyclic voltammetry (CV) and UV-Vis spectrometer at the same time. It takes less than 1.5 s for the color to change from red to green under 0.9 V. Its cycle life is at least over 500 times. Furthermore, we also investigate its photoelectric conversion properties. Its photoelectric cell exhibits a positive photo-electricity conversion effect with a short-circuit photocurrent (46.4 μA/cm 2 ) under illumination of white light (1.201 mW/cm 2 )

  10. Overlapping Open Clusters NGC 1750 and NGC 1758 behind the Taurus Dark Clouds. II. CCD Photometry in the Vilnius System

    Straižys V.

    2003-09-01

    Full Text Available Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V = 16 mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions and distances are given for 287 stars. The classification of stars is based on their reddening-free Q-parameters. 18 stars observed photoelectrically were used as standards. The extinction vs. distance diagram exhibits the presence of one dust cloud at a distance of 175 pc which almost coincides with a distance of other dust clouds in the Taurus complex. The clusters NGC 1750 and NGC 1758 are found to be at the same distance of ~760 pc and may penetrate each other. Their interstellar extinction AV is 1.06 mag which corresponds to EB-V = 0.34 mag.

  11. Photographic infrared spectroscopy and near infrared photometry of Be stars

    Swings, J.P.

    1976-01-01

    Two topics are tackled in this presentation: spectroscopy and photometry. The following definitions are chosen: photographic infrared spectroscopy (wavelengths Hα<=lambda<1.2 μ); near infrared photometry (wavebands: 1.6 μ<=lambda<=20 μ). Near infrared spectroscopy and photometry of classical and peculiar Be stars are discussed and some future developments in the field are outlined. (Auth.)

  12. Photometry and polarimetry of Nova Andromedae 1986

    Kikuchi, Sen; Mikami, Yoshitaka; Kondo, Masayuki

    1988-01-01

    We have carried out photometry of Nova Andromedae 1986 and find that it should be classified as a fast nova. We have also made polarimetry simultaneously at six wavelengths between 0.36-0.70 ..mu..m. The polarization increased between 2 and 22 days after the light maximum showing that dust formation was associated with the nova explosion.

  13. L' AND M' Photometry Of Ultracool Dwarfs

    Marley, M

    2004-01-01

    We have compiled L' (3.4-4.1 microns) and M' (4.6-4.8 microns) photometry of 63 single and binary M, L, and T dwarfs obtained at the United Kingdom Infrared Telescope using the Mauna Kea Observatory filter set...

  14. SURFACE PHOTOMETRY OF LOW SURFACE BRIGHTNESS GALAXIES

    DEBLOK, WJG; VANDERHULST, JM; BOTHUN, GD

    1995-01-01

    Low surface brightness (LSB) galaxies are galaxies dominated by an exponential disc whose central surface brightness is much fainter than the value of mu(B)(0) = 21.65 +/- 0.30 mag arcsec(-2) found by Freeman. In this paper we present broadband photometry of a sample of 21 late-type LSB galaxies.

  15. The Space Stellar Photometry Mission COROT: Asteroseismology ...

    tribpo

    detect giant extra solar planets (detectable by spectroscopy from the ground) and determine their albedo. As COROT is devoted to stellar photometry, aiming at both a high precision and a long observation time, the search for exoplanets by the transit method can easily be integrated in the payload and in the mission profile.

  16. Calibration of the MACHO Photometry Database

    Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Geha, M.

    1999-01-01

    The MACHO Project is a microlensing survey that monitors the brightnesses of ∼60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. Calibrated MACHO photometry may be properly compared with all other observations on the Kron-Cousins standard system, enhancing the astrophysical value of these data. For ∼9 million stars in the LMC bar, independent photometric measurements of ∼20,000 stars with V(less-or-similar sign)18 mag in field-overlap regions demonstrate an internal precision σ V =0.021, σ R =0.019, σ V-R =0.028 mag. The accuracy of the zero point in this calibration is estimated to be ±0.035 mag for stars with colors in the range -0.1 mag< V-R<1.2 mag. A comparison of calibrated MACHO photometry with published photometric sequences and new Hubble Space Telescope observations shows agreement. The current calibration zero-point uncertainty for the remainder of the MACHO photometry database is estimated to be ±0.10 mag in V or R and ±0.04 mag in V-R. We describe the first application of calibrated MACHO data: the construction of a color-magnitude diagram used to calculate our experimental sensitivity for detecting microlensing in the LMC. (c) (c) 1999. The Astronomical Society of the Pacific

  17. Calibration of the MACHO Photometry Database

    Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Geha, M. (and others)

    1999-12-01

    The MACHO Project is a microlensing survey that monitors the brightnesses of {approx}60 million stars in the Large Magellanic Cloud (LMC), Small Magellanic Cloud, and Galactic bulge. Our database presently contains about 80 billion photometric measurements, a significant fraction of all astronomical photometry. We describe the calibration of MACHO two-color photometry and transformation to the standard Kron-Cousins V and R system. Calibrated MACHO photometry may be properly compared with all other observations on the Kron-Cousins standard system, enhancing the astrophysical value of these data. For {approx}9 million stars in the LMC bar, independent photometric measurements of {approx}20,000 stars with V(less-or-similar sign)18 mag in field-overlap regions demonstrate an internal precision {sigma}{sub V} =0.021, {sigma}{sub R} =0.019, {sigma}{sub V-R} =0.028 mag. The accuracy of the zero point in this calibration is estimated to be {+-}0.035 mag for stars with colors in the range -0.1 magphotometry with published photometric sequences and new Hubble Space Telescope observations shows agreement. The current calibration zero-point uncertainty for the remainder of the MACHO photometry database is estimated to be {+-}0.10 mag in V or R and {+-}0.04 mag in V-R. We describe the first application of calibrated MACHO data: the construction of a color-magnitude diagram used to calculate our experimental sensitivity for detecting microlensing in the LMC. (c) (c) 1999. The Astronomical Society of the Pacific.

  18. Time improvement of photoelectric effect calculation for absorbed dose estimation

    Massa, J M; Wainschenker, R S; Doorn, J H; Caselli, E E

    2007-01-01

    Ionizing radiation therapy is a very useful tool in cancer treatment. It is very important to determine absorbed dose in human tissue to accomplish an effective treatment. A mathematical model based on affected areas is the most suitable tool to estimate the absorbed dose. Lately, Monte Carlo based techniques have become the most reliable, but they are time expensive. Absorbed dose calculating programs using different strategies have to choose between estimation quality and calculating time. This paper describes an optimized method for the photoelectron polar angle calculation in photoelectric effect, which is significant to estimate deposited energy in human tissue. In the case studies, time cost reduction nearly reached 86%, meaning that the time needed to do the calculation is approximately 1/7 th of the non optimized approach. This has been done keeping precision invariant

  19. Application and research of artificial water mist on photoelectric interference

    He, Yuejun; Ren, Baolin

    2018-04-01

    Water mist is a new type of photoelectric interfering material. It can exert a strong interference and shielding effect on infrared light, laser and radar wave through scattering, reflection, refraction and absorption. Based on this, this paper illustrates the application of an artificial high pressure water mist technology in infrared interference system. First, the operating principle of the infrared interference system is introduced. Next, the design principle of self-excited rotary vortex nozzle, the key part of the system, is elaborated. Then, the calculation of the main control parameters of the system is clarified. In the end, the paper verifies interference and shielding effect of the system by experiment. Experiment shows that the interference system can significantly reduce infrared signature of the target, featuring excellent infrared interference performance and high practical value.

  20. Photoelectric equipment type MFS-7 for analyzing oils

    Orlova, S.A.; Fridman, M.G.; Kholosha, T.V.; Ezhoda, G.D.; Nechitailov, V.V.

    1987-01-01

    The authors describe the equipment type MFS-7 which is intended for analyzing used oils for the wear products of motors. The difference between type MFS-7 and its predecessors lies in the application of computer techniques to control the equipment and process the output data; and in the design of the sample container, which allows for two methods of introducing the sample into the discharge. The photoelectric equipment consists of an excitation spectrum source IVS-28, having an ac arc mode and 1.v. spark, a polychoromator, a special sample holder for analyzing liquid samples, an electronic recording apparatus with digital voltmeter type ERU-18 and control computer system Spectr 2.2 based on a minicomputer with its own printer. The type MFS-7 equipment has been tested and put into mass production

  1. BRITE Constellation: data processing and photometry

    Popowicz, A.; Pigulski, A.; Bernacki, K.; Kuschnig, R.; Pablo, H.; Ramiaramanantsoa, T.; Zocłońska, E.; Baade, D.; Handler, G.; Moffat, A. F. J.; Wade, G. A.; Neiner, C.; Rucinski, S. M.; Weiss, W. W.; Koudelka, O.; Orleański, P.; Schwarzenberg-Czerny, A.; Zwintz, K.

    2017-09-01

    Context. The BRIght Target Explorer (BRITE) mission is a pioneering space project aimed at the long-term photometric monitoring of the brightest stars in the sky by means of a constellation of nanosatellites. Its main advantage is high photometric accuracy and time coverage which are inaccessible from the ground. Its main drawback is the lack of cooling of the CCD detectors and the absence of good shielding that would protect them from energetic particles. Aims: The main aim of this paper is the presentation of procedures used to obtain high-precision photometry from a series of images acquired by the BRITE satellites in two modes of observing, stare and chopping. The other aim is a comparison of the photometry obtained with two different pipelines and a comparison of the real scatter with expectations. Methods: We developed two pipelines corresponding to the two modes of observing. They are based on aperture photometry with a constant aperture, circular for stare mode of observing and thresholded for chopping mode. Impulsive noise is a serious problem for observations made in the stare mode of observing and therefore in the pipeline developed for observations made in this mode, hot pixels are replaced using the information from shifted images in a series obtained during a single orbit of a satellite. In the other pipeline, the hot pixel replacement is not required because the photometry is made in difference images. Results: The assessment of the performance of both pipelines is presented. It is based on two comparisons, which use data from six runs of the UniBRITE satellite: (I) comparison of photometry obtained by both pipelines on the same data, which were partly affected by charge transfer inefficiency (CTI), (II) comparison of real scatter with theoretical expectations. It is shown that for CTI-affected observations, the chopping pipeline provides much better photometry than the other pipeline. For other observations, the results are comparable only for data

  2. The research on teaching reformation of photoelectric information science and engineering specialty experiments

    Zhu, Zheng; Yang, Fan; Zhang, Yang; Geng, Tao; Li, Yuxiang

    2017-08-01

    This paper introduced the idea of teaching reformation of photoelectric information science and engineering specialty experiments. The teaching reformation of specialty experiments was analyzed from many aspects, such as construction of specialized laboratory, experimental methods, experiment content, experiment assessing mechanism, and so on. The teaching of specialty experiments was composed of four levels experiments: basic experiments, comprehensive and designing experiments, innovative research experiments and engineering experiments which are aiming at enterprise production. Scientific research achievements and advanced technology on photoelectric technology were brought into the teaching of specialty experiments, which will develop the students' scientific research ability and make them to be the talent suitable for photoelectric industry.

  3. Infrared photometry, extinction curves and R values for stars in the southern Milky Way

    Whittet, D.C.B.; Breda, I.G. Van; Glass, I.S.

    1976-01-01

    Infrared photometry in the JHKL bands is combined with photoelectric scanner photometry to give interstellar extinction curves in the range lambda 0.34 to 3.4 μ for 22 early-type stars in the Southern Milky Way. The extinction curves show variations in curvature in the infrared which are related to the well-known change in slope in the near ultraviolet. The curves are extrapolated to lambda -1 = 0 with the aid of Mie theory computations for a graphite-iron-silicate grain model, and values of the ratio of total to selective extinction R = Asub(v)/Esub(B-V) are deduced. R is found to vary between 2.7 and 3.5 with a median value of 3.2 for stars with long-path-length reddening, while two stars in the rho Ophiuchi dark cloud have R values of 3.6 and 4.3. The variations found in the extinction curves probably result from regional fluctuations in the mean grain size and/or composition along the line of sight, and any systematic variation in R with galactic longitude is likely to be small. The derived R values are correlated with the wavelength of maximum polarization. R is found to be normal for HD 90706 in the cluster IC 2581, for which a high R value has been suggested. It is noted that R has now been shown to lie in the range 4.1 to 4.4 for stars in the denser regions of the rho Ophiuchi cloud by four independent methods. None of the observed stars show strong infrared excess radiation at 3.4 μ. Small excesses measured for a few high-luminosity stars associated with mass loss may be due to free-free emission in gaseous stellar envelopes. (author)

  4. BVRI main-sequence photometry of the globular cluster M4

    Alcaino, G.; Liller, W.

    1984-01-01

    We present BV and RI photographic photometry of 1421 and 189 stars, respectively, in the intermediate metallicity globular cluster M4 (NGC 6121). This investigation includes the first results of RI main-sequence photometry of a globular cluster. The use of longer wavelengths and longer color baselines provides the potential of improved isochrone fittings and underscores the urgent need for calculations of RI synthetic isochrones to be compared with observations. The Pickering-Racine wedge was used with the ESO 3.6 m telescope, the Las Campanas 2.5 m du Pont telescope, and the CTIO 1 m Yale telescope to extend the photoelectric limit from Vroughly-equal16.1 to Vroughly-equal19.1. We have determined the position of the main-sequence turnoff to lie at V = 16.6 +- 0.2 (m.e.) and B-V = 0.80 +- 0.03 (m.e.). A comparison of our BV observations with the CCD data of Richer and Fahlman shows excellent agreement: the two fifucial main sequences agree at all points to within 0.025 mag and, on average, to 0.013 mag. For the cluster we derive a distance modulus (m-M)/sub V/ = 12.52 +- 0.2 and reddening E(B-V) = 0.44 +- 0.03, results which confirm that at a distance of 2 kpc, M4 is the closest globular clusters to the Sun. Using the isochrones of VandenBerg, we deduce an age 13 +- 2 Gyr. As noted in several other investigations, there is a striking deficiency of stars in certain parts of the color-magnitude diagram; in M4 we find a pronounced gap over approx.0.6 mag at the base of the subgiant branch

  5. Laser flare photometry in clinical practice

    Yury S Astakhov

    2016-06-01

    Full Text Available Laser flare photometry (LFP is the only quantitative and objective method for the evaluation of aqueous flare. There are numerous opportunities to use LFP in clinical practice, and they are discussed in the paper. It is especially helpful in management of uveitis patients, because it allows estimating the correct diagnosis, managing the patient during the treatment with noninvasive method and predicting relapses and complications.

  6. Improved moving source photometry with TRIPPy

    Alexandersen, Mike; Fraser, Wesley Cristopher

    2017-10-01

    Photometry of moving sources is more complicated than for stationary sources, because the sources trail their signal out over more pixels than a point source of the same magnitude. Using a circular aperture of same size as would be appropriate for point sources can cut out a large amount of flux if a moving source moves substantially relative to the size of the aperture during the exposure, resulting in underestimated fluxes. Using a large circular aperture can mitigate this issue at the cost of a significantly reduced signal to noise compared to a point source, as a result of the inclusion of a larger background region within the aperture.Trailed Image Photometry in Python (TRIPPy) solves this problem by using a pill-shaped aperture: the traditional circular aperture is sliced in half perpendicular to the direction of motion and separated by a rectangle as long as the total motion of the source during the exposure. TRIPPy can also calculate the appropriate aperture correction (which will depend both on the radius and trail length of the pill-shaped aperture), and has features for selecting good PSF stars, creating a PSF model (convolved moffat profile + lookup table) and selecting a custom sky-background area in order to ensure no other sources contribute to the background estimate.In this poster, we present an overview of the TRIPPy features and demonstrate the improvements resulting from using TRIPPy compared to photometry obtained by other methods with examples from real projects where TRIPPy has been implemented in order to obtain the best-possible photometric measurements of Solar System objects. While TRIPPy has currently mainly been used for Trans-Neptunian Objects, the improvement from using the pill-shaped aperture increases with source motion, making TRIPPy highly relevant for asteroid and centaur photometry as well.

  7. Determination of palladium by flame photometry

    Parellada Bellod, R.

    1964-01-01

    A study on the determination of palladium by lame photometry, fixing the most convent experimental conditions and using solvents to increase the emission of this elements is carried out. Among the organic solvents, acetone has been found the most efficient. The interferences produced by anions and cations have also been studied and an analytical method is related, in which lines of calibration of 0 to 100 ppm palladium re used. (Author) 7 refs

  8. Lightcurve Photometry Opportunities: 2018 April-June

    Warner, Brian D.; Harris, Alan W.; Durech, Josef; Benner, Lance A. M.

    2018-04-01

    We present lists of asteroid photometry opportunities for objects reaching a favorable apparition and having either none or poorly-defined lightcurve parameters. Additional data on these objects will help with shape and spin axis modeling via lightcurve inversion. We also include lists of objects that will be the target of radar observations. Lightcurves for these objects can help constrain pole solutions and/or remove rotation period ambiguities that might not come from using radar data alone.

  9. Thirteen-colour photometry of Be stars

    Alvarez, M; Schuster, W J [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    Thirteen-colour photometry made at the San Pedro Martir Observatory in Baja California, for a number of spectroscopically variable Be and shell stars is presented. Several of these stars also show photometric variability in the ultraviolet and/or infrared over a time base of two to three years. We analyze the more interesting stars in terms of colour-colour diagrams, colour excesses, spectral characteristics and changes in their energy distributions. Prospects for future research are discussed.

  10. Optical photometry of TX0506+056

    Keel, William; Santander, Marcos

    2017-10-01

    The blazar TX0506+056 has attracted recent attention through its location in the error box of a high-energy Ice Cube neutrino detection (https://gcn.gsfc.nasa.gov/gcn3/21916.gcn3) and gamma-ray flaring (Atel #10791) We report recent photometry of TX0506+056 obtained in Johnson V and Cousins R passbands using the 1-meter Kapteyn telescope at La Palma, operated remotely by the SARA consortium.

  11. Recent photometry of selected symbiotic stars

    Vrašťák, M.

    2018-04-01

    A new multicolour (BVRcIc) photometric observations of symbiotic stars UV Aur, YY Her, V443 Her, V1016 Cyg, PU Vul, V407 Cyg, V471 Per and suspected symbiotic stars ZZ CMi, NQ Gem, V934 Her, V335 Vul, V627 Cas is presented. The data were obtained from 2016 October to 2018 January by the metod of classical CCD photometry. The monitoring program is still running, so on this paper partial light curves are presented.

  12. Thirteen-colour photometry of Be stars

    Alvarez, M.; Schuster, W.J.

    1981-01-01

    Thirteen-colour photometry made at the San Pedro Martir Observatory in Baja California, for a number of spectroscopically variable Be and shell stars is presented. Several of these stars also show photometric variability in the ultraviolet and/or infrared over a time base of two to three years. We analyze the more interesting stars in terms of colour-colour diagrams, colour excesses, spectral characteristics and changes in their energy distributions. Prospects for future research are discussed. (author)

  13. WISE PHOTOMETRY FOR 400 MILLION SDSS SOURCES

    Lang, Dustin; Hogg, David W.; Schlegel, David J.

    2016-01-01

    We present photometry of images from the Wide-Field Infrared Survey Explorer (WISE) of over 400 million sources detected by the Sloan Digital Sky Survey (SDSS). We use a “forced photometry” technique, using measured SDSS source positions, star–galaxy classification, and galaxy profiles to define the sources whose fluxes are to be measured in the WISE images. We perform photometry with The Tractor image modeling code, working on our “unWISE” coaddds and taking account of the WISE point-spread function and a noise model. The result is a measurement of the flux of each SDSS source in each WISE band. Many sources have little flux in the WISE bands, so often the measurements we report are consistent with zero given our uncertainties. However, for many sources we get 3σ or 4σ measurements; these sources would not be reported by the “official” WISE pipeline and will not appear in the WISE catalog, yet they can be highly informative for some scientific questions. In addition, these small-signal measurements can be used in stacking analyses at the catalog level. The forced photometry approach has the advantage that we measure a consistent set of sources between SDSS and WISE, taking advantage of the resolution and depth of the SDSS images to interpret the WISE images; objects that are resolved in SDSS but blended together in WISE still have accurate measurements in our photometry. Our results, and the code used to produce them, are publicly available at http://unwise.me

  14. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-07-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  15. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing; Diao, Dongfeng

    2016-01-01

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  16. A device for automatic photoelectric control of the analytical gap for emission spectrographs

    Dietrich, John A.; Cooley, Elmo F.; Curry, Kenneth J.

    1977-01-01

    A photoelectric device has been built that automatically controls the analytical gap between electrodes during excitation period. The control device allows for precise control of the analytical gap during the arcing process of samples, resulting in better precision of analysis.

  17. Nanosized graphene sheets enhanced photoelectric behavior of carbon film on p-silicon substrate

    Yang, Lei; Hu, Gaijuan; Zhang, Dongqing [Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System, School of Mechanical Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Diao, Dongfeng, E-mail: dfdiao@szu.edu.cn [Institute of Nanosurface Science and Engineering (INSE), Shenzhen University, Shenzhen 518060 (China)

    2016-07-18

    We found that nanosized graphene sheets enhanced the photoelectric behavior of graphene sheets embedded carbon (GSEC) film on p-silicon substrate, which was deposited under low energy electron irradiation in electron cyclotron resonance plasma. The GSEC/p-Si photodiode exhibited good photoelectric performance with photoresponsivity of 206 mA/W, rise and fall time of 2.2, and 4.3 μs for near-infrared (850 nm) light. The origin of the strong photoelectric behavior of GSEC film was ascribed to the appearance of graphene nanosheets, which led to higher barrier height and photoexcited electron-collection efficiency. This finding indicates that GSEC film has the potential for photoelectric applications.

  18. Inventory Control: Construction of a Photoelectric Colorimeter and Application to Students' Experiments (Part 2).

    Matsuo, Tsutomu; And Others

    1989-01-01

    Discussed are the construction and uses of a version of a photoelectric colorimeter by students. Included are materials needed and four experiments which use the equipment. Sample results are shown. (CW)

  19. The photoelectric yield technique for the characterization of the semiconductor heterostructures

    Evangelisti, F.; Di Gaspare, L.

    1998-01-01

    The paper discusses the use of the photoelectric yield spectroscopy for investigating surface defects and interfaces. Few examples are presented that clearly show the usefulness of the techniques. The heterostructures discussed include crystalline/amorphous and crystalline/crystalline systems

  20. Experimentation in the teaching of Modern Physics: Photoelectric Effect with neon lamp and LEDs

    Dario Eberhardt

    2017-12-01

    Full Text Available The article presents an experiment aimed at the teaching of Physics in High School, specifically the Photoelectric Effect, and it aims to support the teacher or serve as an inspiration for the proposition of other didactic activities. The experimentation consists on the exposure of a neon lamp to the lights of different wavelengths emitted by varied LEDs. The photoelectric current is measured on electrodes of the neon lamp, verifying that it has definite direction; the effect occurs when the wavelength of the applied light is less than a certain limit, and; the intensity of the photoelectric current depends on the intensity of the light applied, in agreement with the current scientific model of the phenomenon. This text also includes many decisive moments of the history of the Photoelectric Effect, characteristics of similar experiments using ultraviolet light, the electron work function of the metals of the electrodes and the ionization energy of the gases inside the lamp.

  1. Photoelectric effect from observer's mathematics point of view

    Khots, Boris; Khots, Dmitriy

    2014-12-01

    When we consider and analyze physical events with the purpose of creating corresponding models we often assume that the mathematical apparatus used in modeling is infallible. In particular, this relates to the use of infinity in various aspects and the use of Newton's definition of a limit in analysis. We believe that is where the main problem lies in contemporary study of nature. This work considers Physical aspects in a setting of arithmetic, algebra, geometry, analysis, topology provided by Observer's Mathematics (see www.mathrelativity.com). Certain results and communications pertaining to solution of these problems are provided. In particular, we prove the following Theorems, which give Observer's Mathematics point of view on Einstein photoelectric effect theory and Lamb-Scully and Hanbury-Brown-Twiss experiments: Theorem 1. There are some values of light intensity where anticorrelation parameter A ∈ [0,1). Theorem 2. There are some values of light intensity where anticorrelation parameter A = 1. Theorem 3. There are some values of light intensity where anticorrelation parameter A > 1.

  2. Photometry of Pluto-Charon mutual events and Hirayama family asteroids

    Binzel, R.P.

    1988-01-01

    Once every 124 years, nature provides earth-bound astronomers with the opportunity to observe occultation and transit phenomena between Pluto and its satellite, Charon. Ground-based observations of these events will allow precise physical parameters for the Pluto-Charon system to be derived which are unlikely to be improved upon until in situ spacecraft observations are obtained. The proposed program will continue to support photometry observations from McDonald Observatory, a critical location in an international Pluto Campaign network. Knowledge of the diameters, masses, densities, and compositions derived from these observations will augment our understanding of Pluto's origin and its context within the problem of solar system formation. A second task will continue to research the evolutionary processes which have occurred in the asteroid belt by measuring the physical properties of specific Hirayama family members. Photoelectric lightcurve observations of Koronis and Themis family members will be used to investigate the individual catastrophic collision events which formed each family. By comparing these properties with results of laboratory and numerical experiments, the outcomes of catastrophic disruptions and collisional evolution may be more precisely determined

  3. Ceres Photometry and Albedo from Dawn Framing Camera Images

    Schröder, S. E.; Mottola, S.; Keller, H. U.; Li, J.-Y.; Matz, K.-D.; Otto, K.; Roatsch, T.; Stephan, K.; Raymond, C. A.; Russell, C. T.

    2015-10-01

    The Dawn spacecraft is in orbit around dwarf planet Ceres. The onboard Framing Camera (FC) [1] is mapping the surface through a clear filter and 7 narrow-band filters at various observational geometries. Generally, Ceres' appearance in these images is affected by shadows and shading, effects which become stronger for larger solar phase angles, obscuring the intrinsic reflective properties of the surface. By means of photometric modeling we attempt to remove these effects and reconstruct the surface albedo over the full visible wavelength range. Knowledge of the albedo distribution will contribute to our understanding of the physical nature and composition of the surface.

  4. Stroemgren photometry of southern white dwarfs

    Bessell, M.S.; Wickramasinghe, D.T.

    1978-01-01

    Colours of southern white dwarfs in the uvby (Stroemgren four-colour) system have been obtained. The results are compared with those of Graham. The extensive absolute photometry of white dwarfs published by Greenstein has also been transferred into the four-colour system and both sets of results are compared with model atmosphere calculations. The scatter in log (g) is higher than previously supposed, and the evidence for an increase in at the cooler (Tsub(e) < 10 000 K) end of the DA sequence is discussed. (author)

  5. Switchable narrow band reflectors produced in a single curing step

    2006-01-01

    A method to produce a multiphase polymer-based film by polymg. monomer in the presence of a non-reactive liq. crystal and a dichroic photoinitiator whereby the polymn. is initiated by the use of linearly polarized light, the initial mixt. being cholesteric before polymn. is described. A multiphase

  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. Subwavelength-Sized Narrow-Band Anechoic Waveguide Terminations

    Santillan, Arturo Orozco; Ærenlund, Emil; Bozhevolnyi, Sergey I.

    2016-01-01

    We propose and demonstrate the use of a pair of detuned acoustic resonators to efficiently absorb narrowband sound waves in a terminated waveguide. The suggested configuration is relatively simple and advantageous for usage at low frequencies, since the dimensions of the resonators are very small...

  8. Optimum filters for narrow-band frequency modulation.

    Shelton, R. D.

    1972-01-01

    The results of a computer search for the optimum type of bandpass filter for low-index angle-modulated signals are reported. The bandpass filters are discussed in terms of their low-pass prototypes. Only filter functions with constant numerators are considered. The pole locations for the optimum filters of several cases are shown in a table. The results are fairly independent of modulation index and bandwidth.

  9. Clinical relevance of narrow-band imaging in flexible cystoscopy

    Drejer, Ditte; Béji, Sami; Munk Nielsen, Anna

    2017-01-01

    urological departments. Patients had either hematuria (n = 483) or known recurrent non-muscle-invasive bladder cancer (NMIBC) (n = 472). High-definition (HD) cystoscopy was performed in white light (WL) and a preliminary clinical decision was made. Then, a second cystoscopy was performed in NBI...... in NBI compared to WL (NBI: 100.0% vs WL: 83.2%, p decision making as a supplement to WL because it yields a significantly higher...... and a conclusive clinical decision was made. A difference between the two decisions that had a clinical impact on the patient was considered clinically relevant. RESULTS: Pathology was found in 216 WL cystoscopies, and additional pathology in 15 NBI cystoscopies (6.9%). Based on NBI, pathology was suspected in 23...

  10. Synthesis and photoluminescence study of narrow-band UVB ...

    [7] Guo C, Ding X, Seo H J, Ren Z and Bai J 2011 J. Alloys. Compd. 509 4871. [8] Zhang X, Lang H and Seo H 2011 J. Fluoresc. 21 1111. [9] Zhang Z W 2013 Ceram. Int. 39 1723. [10] Yu H 2012 J. Lumin. 132 2553. [11] Wang Q 2012 J. Lumin. 132 434. [12] Palan C, Bajaj N and Omanwar S 2016 Mater. Res. Bull. 76 216.

  11. Formation of Electron Strings in Narrow Band Polar Semiconductors

    Kusmartsev, F. V.

    2000-01-01

    We show that linear electron strings may arise in polar semiconductors. A single string consists of M spinless fermions trapped by an extended polarization well of a cigar shape. Inside the string the particles are free although they interact with each other via Coulomb forces. The strings arise as a result of an electronic phase separation associated with an instability of small adiabatic polarons. We have found the length of the string which depends on dielectric constants of semiconductors. The appearance of these electron strings may have an impact on the effect of stripe formation observed in a variety of high- Tc experiments.

  12. Quantum Dot Detector Enhancement for Narrow Band Multispectral Applications

    2013-12-01

    22 Figure 22: (a) 4 Silver Nanospheres in Ring Formation; (b) Quality Factor for a 4 and 6 Nanosphere Ring Centered on...centered on. Here, the radius of the ring is varied from 60 to 400 nm. Figure 22:(a) 4 Silver Nanospheres in Ring Formation; (b) Quality Factor...QE )Iα at the resonant wavelength. From Figure 22 highest Q≈ 0.8 for the nanorings , but for there to be an increase in the I , Q must be greater

  13. Experimental studies of narrow band effects in the actinides

    Brodsky, M.B.

    1976-01-01

    In many actinide metallic systems the f-electrons exhibit band behavior. This is a consequence of direct f-f wave function overlap or hybridization of f-electrons with s-, p-, and d-electrons. The f-bands can be responsible for large electronic densities of states at the Fermi level which may lead to band magnetism of various types. Although the concept of valence instabilities must be approached cautiously especially in the light actinides, it would not be surprising to observe them in the future, especially in Am compounds.

  14. Experimental studies of narrow band effects in the actinides

    Brodsky, M.B.

    1976-01-01

    In many actinide metallic systems the f-electrons exhibit band behavior. This is a consequence of direct f-f wave function overlap or hybridization of f-electrons with s-, p-, and d-electrons. The f-bands can be responsible for large electronic densities of states at the Fermi level which may lead to band magnetism of various types. Although the concept of valence instabilities must be approached cautiously especially in the light actinides, it would not be surprising to observe them in the future, especially in Am compounds

  15. Modeling of radiant heat transfers in non-grey gases using the discrete ordinate method in association with a narrow bands statistical model; Modelisation des transferts radiatifs dans des gaz non gris par la methode des ordonnees discretes associee a un modele statistique a bandes etroites

    Miranda, A.B. de; Delmas, A; Sacadura, J F [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)

    1997-12-31

    A formulation based on the use of the discrete ordinate method applied to the integral form of the radiant heat transfer equation is proposed for non-grey gases. The correlations between transmittances are neglected and no explicit wall reflexion is considered. The configuration analyzed consists in a flat layer of non-isothermal steam-nitrogen mixture. Cavity walls are grey with diffuse reflexion and emission. A narrow band statistical model is used to represent the radiative properties of the gas. The distribution of the radiative source term inside the cavity is calculated along two temperature profiles in a uniform steam concentration. Results obtained using this simplified approach are in good agreement with those found in the literature for the same temperature and concentration distributions. This preliminary study seems to indicate that the algorithm based on the integration of radiant heat transfer along the luminance path is less sensitive to de-correlation effects than formulations based on the differential form the the radiant heat transfer. Thus, a more systematic study of the influence of the neglecting of correlations on the integral approach is analyzed in this work. (J.S.) 16 refs.

  16. Modeling of radiant heat transfers in non-grey gases using the discrete ordinate method in association with a narrow bands statistical model; Modelisation des transferts radiatifs dans des gaz non gris par la methode des ordonnees discretes associee a un modele statistique a bandes etroites

    Miranda, A.B. de; Delmas, A.; Sacadura, J.F. [Institut National des Sciences Appliquees (INSA), 69 - Villeurbanne (France)

    1996-12-31

    A formulation based on the use of the discrete ordinate method applied to the integral form of the radiant heat transfer equation is proposed for non-grey gases. The correlations between transmittances are neglected and no explicit wall reflexion is considered. The configuration analyzed consists in a flat layer of non-isothermal steam-nitrogen mixture. Cavity walls are grey with diffuse reflexion and emission. A narrow band statistical model is used to represent the radiative properties of the gas. The distribution of the radiative source term inside the cavity is calculated along two temperature profiles in a uniform steam concentration. Results obtained using this simplified approach are in good agreement with those found in the literature for the same temperature and concentration distributions. This preliminary study seems to indicate that the algorithm based on the integration of radiant heat transfer along the luminance path is less sensitive to de-correlation effects than formulations based on the differential form the the radiant heat transfer. Thus, a more systematic study of the influence of the neglecting of correlations on the integral approach is analyzed in this work. (J.S.) 16 refs.

  17. A new photoelectric ink based on nanocellulose/CdS quantum dots for screen-printing.

    Tang, Aimin; Liu, Yuan; Wang, Qinwen; Chen, Ruisong; Liu, Wangyu; Fang, Zhiqiang; Wang, Lishi

    2016-09-05

    CdS quantum dots with excellent photoelectrical properties embedded in nanocellulose could be exploited for use in photoelectrical ink. In this work, nanocellulose/CdS quantum dot composites were fabricated by controlling the carboxylate content of the nanocellulose and the molar ratio of Cd(2+)/-COOH. New photoelectric inks were prepared based on the composites, in which the CdS quantum dots acted as the pigment and the nanocellulose as the binder. The results of the photocurrent of the composites showed that the photocurrent could be tailored by the carboxylate content and the molar ratio of Cd(2+)/-COOH. And the photocurrent could be as high as 2μA. The surface tension of the photoelectric ink was 27.80±0.03mN/m and its viscosity was 30.3mPas. The photoelectric ink was stable with excellent fluidity and rheology, it could therefore be applied to screen-printing and three-dimensional (3D) printing. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Flatfielding Errors in Strömvil CCD Photometry

    Boyle R. P.

    2003-12-01

    Full Text Available The importance of determining the error of the flat field in CCD photometry is detailed and our methods of doing this are described. We now have reached a precision of 1-1.5 % in our photometry. Color-magnitude diagrams of the open cluster M67 (ours and Laugalys et al. 2003 are compared.

  19. A low noise photoelectric signal acquisition system applying in nuclear magnetic resonance gyroscope

    Lu, Qilin; Zhang, Xian; Zhao, Xinghua; Yang, Dan; Zhou, Binquan; Hu, Zhaohui

    2017-10-01

    The nuclear magnetic resonance gyroscope serves as a new generation of strong support for the development of high-tech weapons, it solves the core problem that limits the development of the long-playing seamless navigation and positioning. In the NMR gyroscope, the output signal with atomic precession frequency is detected by the probe light, the final crucial photoelectric signal of the probe light directly decides the quality of the gyro signal. But the output signal has high sensitivity, resolution and measurement accuracy for the photoelectric detection system. In order to detect the measured signal better, this paper proposed a weak photoelectric signal rapid acquisition system, which has high SNR and the frequency of responded signal is up to 100 KHz to let the weak output signal with high frequency of the NMR gyroscope can be detected better.

  20. Exploration of offering photoelectric experimental general elective courses for college students of science and technology

    Tao, Shen; Sun, Binchao

    2017-08-01

    The necessity of offering photoelectric experiment general elective courses, such as the experiments of modern optical and innovational photoelectric design for non optic-electric's science and engineering students were discussed based on the analysis of the status quo and problems in experimental general elective course in science and engineering colleges of our country. And the characters of photoelectric disciplines, the goal of science and engineering quality-oriented education and the reform of science education at home and abroad were also considered. The instructional objectives, contents and characteristics of the courses were investigated. The specific methods, the CDIO (conceive, design, implement and operate) mode in the general courses has been proposed; the experiences and practical effects of offering these courses were concluded.

  1. Infrared photometry of cool white dwarfs

    Wickramasinghe, D.T.; Allen, D.A.; Bessell, M.S.

    1982-01-01

    The results are presented of a search for the effects of pressure induced H 2 dipole opacity on the infrared JHK magnitudes of cool white dwarfs. LHS 1126 is found to be a very cool (Tsub(e) approximately 4250 K) DC white dwarf with a H rich atmospheric composition dominated by H 2 dipole opacity in the infrared. JHK photometry also favours a H rich atmospheric composition for the DK white dwarfs LP 658-2 and W 489. The surprisingly high proportion of hydrogen rich white dwarfs in the sample appears to suggest that the mechanism which inhibits the accretion of hydrogen in the hotter helium stars becomes less effective at low (Tsub(e) approximately 3 + ion in cool hydrogen rich white dwarf atmospheres is pointed out and it is suggested that the opacity due to this ion may be responsible for the blanketing observed in the U and B magnitudes of some cool white dwarfs. (author)

  2. Multicolor surface photometry of 17 ellipticals

    Franx, M.; Illingworth, G.; Heckman, T.

    1989-01-01

    Multicolor two-dimensional surface photometry was used to obtain radial profiles for surface brightness, color, ellipticity, position angle, and the residuals from the fitted ellipses described by the cos(n phi) and sin(n phi) terms (where n = 3 and 4) for 17 elliptical galaxies. It is found that at radii as large as five times the seeing FWHM, seeing can affect the ellipticity at the 10 percent level and introduce uncertainty in the position angles of several degrees, particularly for very round ellipticals. The present profiles are found to agree well with previous data, with rms differences of 0.02 in ellipticity and 2 deg in position angle. The observed color gradients are consistent with a decrease in the metallicity by a factor of about 2 per decade in radius. 61 refs

  3. Direct illumination LED calibration for telescope photometry

    Barrelet, E.; Juramy, C.

    2008-01-01

    A calibration method for telescope photometry, based on the direct illumination of a telescope with a calibrated light source regrouping multiple LEDs, is proposed. Its purpose is to calibrate the instrument response. The main emphasis of the proposed method is the traceability of the calibration process and a continuous monitoring of the instrument in order to maintain a 0.2% accuracy over a period of years. Its specificity is to map finely the response of the telescope and its camera as a function of all light ray parameters. This feature is essential to implement a computer model of the instrument representing the variation of the overall light collection efficiency of each pixel for various filter configurations. We report on hardware developments done for SNDICE, the first application of this direct illumination calibration system which will be installed in Canada France Hawaii telescope (CFHT) for its leading supernova experiment (SNLS)

  4. Extended Aperture Photometry of K2 RR Lyrae stars

    Plachy Emese

    2017-01-01

    Full Text Available We present the method of the Extended Aperture Photometry (EAP that we applied on K2 RR Lyrae stars. Our aim is to minimize the instrumental variations of attitude control maneuvers by using apertures that cover the positional changes in the field of view thus contain the stars during the whole observation. We present example light curves that we compared to the light curves from the K2 Systematics Correction (K2SC pipeline applied on the automated Single Aperture Photometry (SAP and on the Pre-search Data Conditioning Simple Aperture Photometry (PDCSAP data.

  5. Extended Aperture Photometry of K2 RR Lyrae stars

    Plachy, Emese; Klagyivik, Péter; Molnár, László; Sódor, Ádám; Szabó, Róbert

    2017-10-01

    We present the method of the Extended Aperture Photometry (EAP) that we applied on K2 RR Lyrae stars. Our aim is to minimize the instrumental variations of attitude control maneuvers by using apertures that cover the positional changes in the field of view thus contain the stars during the whole observation. We present example light curves that we compared to the light curves from the K2 Systematics Correction (K2SC) pipeline applied on the automated Single Aperture Photometry (SAP) and on the Pre-search Data Conditioning Simple Aperture Photometry (PDCSAP) data.

  6. Photoelectric Emission Measurements on the Analogs of Individual Cosmic Dust Grains

    Abbas, M. M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, E. A.; Weingartner, J. C.; Tielens, A. G. G. M.; Nuth, J. a.; Camata, R. P.

    2006-01-01

    The photoelectric emission process is considered to be the dominant mechanism for charging of cosmic dust grains in many astrophysical environments. The grain charge and equilibrium potentials play an important role in the dynamical and physical processes that include heating of the neutral gas in the interstellar medium, coagulation processes in the dust clouds, and levitation and dynamical processes in the interplanetary medium and planetary surfaces and rings. An accurate evaluation of photoelectric emission processes requires knowledge of the photoelectric yields of individual dust grains of astrophysical composition as opposed to the values obtained from measurements on flat surfaces of bulk materials, as it is generally assumed on theoretical considerations that the yields for the small grains are much different from the bulk values. We present laboratory measurements of the photoelectric yields of individual dust grains of silica, olivine, and graphite of approx. 0.09-5 micrometer radii levitated in an electrodynamic balance and illuminated with ultraviolet radiation at 120-160 nm wavelengths. The measured yields are found to be substantially higher than the bulk values given in the literature and indicate a size dependence with larger particles having order-of-magnitude higher values than for submicron-size grains.

  7. Photoelectric UBVRI sequences in the Galactic globular clusters NGC 6752 and NGC 6864

    Alvarado, F.; Wenderoth, E.; Alcaino, G.; Liller, W.

    1990-01-01

    UBVRI photoelectric sequences for the Galactic globular clusters NGC 6752 and NGC 6864 are presented. Both of them include fields suitable for CCD exposures. From five UBV sequences in NGC 6572, only five stars are in common with the previous works. 15 refs

  8. Inventory Control: Construction of a Photoelectric Colorimeter and Application to Students' Experiments.

    Matsuo, Tsutomu; And Others

    1989-01-01

    Presented is a photoelectric colorimeter which can be assembled by the student. Reports that it can do many of the same analyses as the SPEC 20 but at a greatly reduced cost using older technology. Presents several experiments to use with the colorimeter. (MVL)

  9. Thought waves remotely affect the performance (output voltage) of photoelectric cells

    Cao, Dayong; Cao, Daqing

    2012-02-01

    In our experiments, thought waves have been shown to be capable of changing (affecting) the output voltage of photovoltaic cells located from as far away as 1-3 meters. There are no wires between brain and photoelectric cell and so it is presumed only the thought waves act on the photoelectric cell. In continual rotations, the experiments tested different solar cells, measuring devices and lamps, and the experiments were done in different labs. The first experiment was conducted on Oct 2002. Tests are ongoing. Conclusions and assumptions include: 1) the slow thought wave has the energy of space-time as defined by C1.00007: The mass, energy, space and time systemic theory- MEST. Every process releases a field effect electrical vibration which be transmitted and focussed in particular paths; 2) the thought wave has the information of the order of tester; 3) the brain (with the physical system of MEST) and consciousness (with the spirit system of the mind, consciousness, emotion and desire-MECD) can produce the information (a part of them as the Genetic code); 4) through some algorithms such as ACO Ant Colony Optimization and EA Evolutionary Algorithm (or genetic algorithm) working in RAM, human can optimize the information. This Optimizational function is the intelligence; 5) In our experiments, not only can thought waves affect the voltage of the output photoelectric signals by its energy, but they can also selectively increase or decrease those photoelectric currents through remote consciousness interface and a conscious-brain information technology.

  10. Ten colour photometry of twelve Ap-stars

    Musielok, B.; Lange, D.; Schoeneich, W.; Hildebrandt, G.; Zelwanowa, E.; Hempelmann, A.; Salmanov, G.

    1980-01-01

    Ten-colour photoelectric observations are presented for twelve Ap-stars. Improved ephemeris for seven of them is given. Phase relations between the light curves and line intensity variations are discussed. The problem of the electromagnetic flux conctancy of IOTA Cas is approached from a qualitative point of view. (author)

  11. UBV-photometry of nests of interacting galaxies

    Arkhipova, V.P.

    1982-01-01

    The results of photoelectric UBV-observations of 19 nests of interacting galaxies, made at the Crimean Station of the Sternberg Institute, are given. Most of the nests observed were found to be and to have high luminosity. The UBV and spectral data show a large amount of gas inside many nests [ru

  12. Near infrared photometry of globular clusters

    Evans, T.L.; Menzies, J.W.

    1977-01-01

    Photographic photometry on the V, Isub(K) system has been obtained for giant stars in the metal-rich globular clusters NGC 5927, 6171, 6352, 6356, 6388, 6522, 6528, 6712 and 6723. Colour-magnitude diagrams are presented. These data, with earlier observations of NGC 104 (47 Tuc), yield new parameters to describe the giant branch. These are the colour of the red variables, represented by their mean colour (V - Isub(K)) 0 or by the colour (V - Isub(K))sub(BO) of the bluest red variable on the giant branch of a cluster, and ΔV' which is the magnitude difference between the horizontal branch and the highest point on the giant branch. The latter is independent of reddening, since the giant branch of the most metal-rich clusters passes through a maximum in the V, V - Isub(K) plane. These parameters are correlated with the metal content, deduced from integrated photometry: the red variables are redder and the giant branch fainter the higher the metal content. Comparison with theoretical evolutionary tracks suggests that the range in metal content of these clusters is at most a factor of 10, the most metal-rich clusters possibly approaching the solar value. The cluster giant branches and those of open clusters, groups and field stars of the old disk population are compared. The assumption that all the globular clusters have an absolute magnitude on the horizontal branch of Msub(v) = + 0.9, as found recently for 47 Tuc, gives good agreement between the magnitudes of giant stars in the most metal rich of the globular clusters and those of field stars deduced from statistical parallaxes and moving group parallaxes. The values of the parameters ΔV' and (V - Isub(k))sub(BO) also approach those in the moving groups. The globular clusters have a longer horizontal branch, however, and the subgiants are bluer even when the values of ) 7Fe/H{ appear to be the same. (author). )

  13. APPHi: Automated Photometry Pipeline for High Cadence Large Volume Data

    Sánchez, E.; Castro, J.; Silva, J.; Hernández, J.; Reyes, M.; Hernández, B.; Alvarez, F.; García T.

    2018-04-01

    APPHi (Automated Photometry Pipeline) carries out aperture and differential photometry of TAOS-II project data. It is computationally efficient and can be used also with other astronomical wide-field image data. APPHi works with large volumes of data and handles both FITS and HDF5 formats. Due the large number of stars that the software has to handle in an enormous number of frames, it is optimized to automatically find the best value for parameters to carry out the photometry, such as mask size for aperture, size of window for extraction of a single star, and the number of counts for the threshold for detecting a faint star. Although intended to work with TAOS-II data, APPHi can analyze any set of astronomical images and is a robust and versatile tool to performing stellar aperture and differential photometry.

  14. Discovery of a Probable Nova in M81 and Photometry of Three M81 Novae

    Hornoch, K.; Errmann, R.; Carlisle, Ch.; Vaduvescu, O.

    2015-02-01

    We report the discovery of a probable nova in M81 on a co-added 1600-s narrow-band H-alpha CCD image taken with the 2.5-m Isaac Newton Telescope (INT) + WFC at La Palma under ~1.6" seeing on 2015 Jan.

  15. BVI CCD photometry of 47 Tucanae

    Alcaino, G.; Liller, W.

    1987-01-01

    CCD BVI main-sequence photometry of 47 Tuc is presented, matched to the recent BVI isochrones of VandenBerg and Bell (1985). The main-sequence turnoffs are found to be at V = 17.60 + or - 0.1, B-V = 0.56 + or - 0.02; V-I = 0.68 + or - 0.02, and B-I = 1.24 + or - 0.02. The magnitude difference between the main-sequence turnoff and the horizontal branch is 3.55 + or - 0.15 for all three color indices. A consistent age for 47 Tuc of 17 Gyr and a consistent distance modulus of (m-M)v = 13.2 are obtained for all three indices, and an absolute magnitude of Mv = 0.85 is determined for the horizontal branch stars. The results also favor the adoption of (Fe/H) near -0.5 as the best abundance value for 47 Tuc. 38 references

  16. UBV photometry of 262 southern galaxies

    Wegner, G.

    1979-01-01

    Multi-aperture photometry of 262 bright southern galaxies in the Johnson UBV system is given. Most of these are south of delta = -30 0 , although some northward to delta = -10 0 are included. A total of 169 objects have published radial velocity determinations. These provide distances, and enable construction of colour-magnitude diagrams for this subset of objects througha physical diameter of 2.0 kpc (with H 0 = 100). The two-colour diagrams for the inner regions of the galaxies differ from those of integrated galaxies due to the colour changes towards their centres. Comparison with theoretical models of Larson and Tinsley (1978) suggest that the colours of the inner portions of most ellipticals and lenticulars are consistent with their having all stars formed at nearly one epoch with little subsequent star formation, while for spirals larger amounts of star formation, either in bursts of continuously, are suggested. This simple picture is complicated by the presence of certain objects having peculiar colours indicative of large amounts of recent star formation. (Auth.)

  17. Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

    Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz [TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany); TRG Diagnostic Imaging, Bayer Schering Pharma AG, 13353 Berlin (Germany); Physikalisch-Technische Bundesanstalt, 10587 Berlin (Germany); Institute of Applied Photonics e.V., 12489 Berlin (Germany); Institute for Scientific Instruments GmbH, 12489 Berlin (Germany); Department of Radiotherapy, Charite Medical Centre, 13353 Berlin (Germany)

    2009-06-15

    Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten K{alpha} emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

  18. Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography.

    Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Rüdiger; Pietsch, Hubertus; Hütter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Lüdemann, Lutz

    2009-06-01

    Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasimonochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kalpha emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement

  19. Photoelectric-enhanced radiation therapy with quasi-monochromatic computed tomography

    Jost, Gregor; Mensing, Tristan; Golfier, Sven; Lawaczeck, Ruediger; Pietsch, Hubertus; Huetter, Joachim; Cibik, Levent; Gerlach, Martin; Krumrey, Michael; Fratzscher, Daniel; Arkadiev, Vladimir; Wedell, Reiner; Haschke, Michael; Langhoff, Norbert; Wust, Peter; Luedemann, Lutz

    2009-01-01

    Photoelectric-enhanced radiation therapy is a bimodal therapy, consisting of the administration of highly radiation-absorbing substances into the tumor area and localized regional irradiation with orthovoltage x-rays. Irradiation can be performed by a modified computed tomography (CT) unit equipped with an additional x-ray optical module which converts the polychromatic, fan-shaped CT beam into a monochromatized and focused beam for energy-tuned photoelectric-enhanced radiotherapy. A dedicated x-ray optical module designed for spatial collimation, focusing, and monochromatization was mounted at the exit of the x-ray tube of a clinical CT unit. Spectrally resolved measurements of the resulting beam were performed using an energy-dispersive detection system calibrated by synchrotron radiation. The spatial photon fluence was determined by film dosimetry. Depth-dose measurements were performed and compared to the polychromatic CT and a therapeutic 6 MV beam. The spatial dose distribution in phantoms using a rotating radiation source (quasi-monochromatic CT and 6 MV, respectively) was investigated by gel dosimetry. The photoelectric dose enhancement for an iodine fraction of 1% in tissue was calculated and verified experimentally. The x-ray optical module selectively filters the energy of the tungsten Kα emission line with an FWHM of 5 keV. The relative photon fluence distribution demonstrates the focusing characteristic of the x-ray optical module. A beam width of about 3 mm was determined at the isocenter of the CT gantry. The depth-dose measurements resulted in a half-depth value of approximately 36 mm for the CT beams (quasi-monochromatic, polychromatic) compared to 154 mm for the 6 MV beam. The rotation of the radiation source leads to a steep dose gradient at the center of rotation; the gel dosimetry yields an entrance-to-peak dose ratio of 1:10.8 for the quasi-monochromatic CT and 1:37.3 for a 6 MV beam of the same size. The photoelectric dose enhancement factor

  20. Investigating the Bright End of LSST Photometry

    Ojala, Elle; Pepper, Joshua; LSST Collaboration

    2018-01-01

    The Large Synoptic Survey Telescope (LSST) will begin operations in 2022, conducting a wide-field, synoptic multiband survey of the southern sky. Some fraction of objects at the bright end of the magnitude regime observed by LSST will overlap with other wide-sky surveys, allowing for calibration and cross-checking between surveys. The LSST is optimized for observations of very faint objects, so much of this data overlap will be comprised of saturated images. This project provides the first in-depth analysis of saturation in LSST images. Using the PhoSim package to create simulated LSST images, we evaluate saturation properties of several types of stars to determine the brightness limitations of LSST. We also collect metadata from many wide-field photometric surveys to provide cross-survey accounting and comparison. Additionally, we evaluate the accuracy of the PhoSim modeling parameters to determine the reliability of the software. These efforts will allow us to determine the expected useable data overlap between bright-end LSST images and faint-end images in other wide-sky surveys. Our next steps are developing methods to extract photometry from saturated images.This material is based upon work supported in part by the National Science Foundation through Cooperative Agreement 1258333 managed by the Association of Universities for Research in Astronomy (AURA), and the Department of Energy under Contract No. DE-AC02-76SF00515 with the SLAC National Accelerator Laboratory. Additional LSST funding comes from private donations, grants to universities, and in-kind support from LSSTC Institutional Members.Thanks to NSF grant PHY-135195 and the 2017 LSSTC Grant Award #2017-UG06 for making this project possible.

  1. One-step electrochemical synthesis and photoelectric conversion of a ZnO/Se/RGO composite

    Wang, Lei; Zhang, Chunyan; Zhang, Shengyi; Niu, Helin; Song, Jiming; Mao, Changjie; Jin, Baokang; Tian, Yupeng

    2015-01-01

    Using Zn(NO 3 ) 2 , H 2 SeO 3 and graphene oxide as precursors, the zinc oxide/selenium/reduced graphene oxide (ZnO/Se/RGO) composite was facilely electrodeposited on the surface of indium tin oxide glass. The conditions for electrochemical synthesis such as electrodeposition potential and electrolyte composition were studied. The morphology and crystallization of the products as-prepared were characterized using scanning electron microscopy (SEM) and x-ray diffractometry (XRD) respectively. The light absorption and conductivity of the products were studied by UV-visible spectroscopy (UV-vis) and electrochemical impedance spectroscopy (EIS). Based on a series of experimental results, the photoelectrical conversion mechanism and effect factors of the products were explored. By means of synergistic action of n-type ZnO, p-type Se and conductive RGO, the ZnO/Se/RGO composite showed excellent photoelectric conversion under visible light irradiation. (paper)

  2. Functionalization of carbon nanotubes/graphene by polyoxometalates and their enhanced photo-electrical catalysis

    Zhang Shuang-Shuang; Liu Rong-Ji; Zhang Guang-Jin; Gu Zhan-Jun

    2014-01-01

    Carbon nanotubes and graphene are carbon-based materials, which possess not only unique structure but also properties such as high surface area, extraordinary mechanical properties, high electronic conductivity, and chemical stability. Thus, they have been regarded as an important material, especially for exploring a variety of complex catalysts. Considerable efforts have been made to functionalize and fabricate carbon-based composites with metal nanoparticles. In this review, we summarize the recent progress of our research on the decoration of carbon nanotubes/graphene with metal nanoparticles by using polyoxometalates as key agents, and their enhanced photo-electrical catalytic activities in various catalytic reactions. The polyoxometalates play a key role in constructing the nanohybrids and contributing to their photo-electrical catalytic properties. (invited review — international conference on nanoscience and technology, china 2013)

  3. Analysis on detection accuracy of binocular photoelectric instrument optical axis parallelism digital calibration instrument

    Ying, Jia-ju; Yin, Jian-ling; Wu, Dong-sheng; Liu, Jie; Chen, Yu-dan

    2017-11-01

    Low-light level night vision device and thermal infrared imaging binocular photoelectric instrument are used widely. The maladjustment of binocular instrument ocular axises parallelism will cause the observer the symptom such as dizziness, nausea, when use for a long time. Binocular photoelectric equipment digital calibration instrument is developed for detecting ocular axises parallelism. And the quantitative value of optical axis deviation can be quantitatively measured. As a testing instrument, the precision must be much higher than the standard of test instrument. Analyzes the factors that influence the accuracy of detection. Factors exist in each testing process link which affect the precision of the detecting instrument. They can be divided into two categories, one category is factors which directly affect the position of reticle image, the other category is factors which affect the calculation the center of reticle image. And the Synthesize error is calculated out. And further distribute the errors reasonably to ensure the accuracy of calibration instruments.

  4. Tunable photoelectric response in NiO-based heterostructures by various orientations

    Luo, Yidong; Qiao, Lina; Zhang, Qinghua; Xu, Haomin; Shen, Yang; Lin, Yuanhua; Nan, Cewen

    2018-02-01

    We engineered various orientations of NiO layers for NiO-based heterostructures (NiO/Au/STO) to investigate their effects on the generation of hot electrons and holes. Our calculation and experimental results suggested that bandgap engineering and the orientation of the hole transport layer (NiO) were crucial elements for the optimization of photoelectric responses. The (100)-orientated NiO/Au/STO achieved the highest photo-current density (˜30 μA/cm2) compared with (111) and (110)-orientated NiO films, which was attributed to the (100) films's lowest effective mass of photogenerated holes (˜1.82 m0) and the highest efficiency of separating and transferring electron-holes of the (100)-orientated sample. Our results opened a direction to design a high efficiency photoelectric solar cell.

  5. Photoelectric properties of GaAs materials studied by pulsed laser techniques

    Aguir, Khalifa

    1981-01-01

    This research thesis addressed the photoelectric properties of single-crystal or epitaxial GaAs (N doped or P doped) materials. The objective is to characterize and to improve the electric quality of these materials and associated components, notably for the production of high performance solar cells for ground-based or space-based applications. More particularly, this research aimed at using an excitation by a pulsed laser to analyse recombination and trapping properties of carriers created by photo-excitation, and also at studying the effect of low doses of particle irradiation on the carrier properties. Thus, the author describes conduction characteristics of two different N-type epitaxial layers, discusses carrier excitation and recombination processes which may occur in semiconductors, and proposes an overview of trapping phenomena. Photoelectric properties of the considered epitaxial layers are then studied and discussed

  6. Finding Exoplanets Using Point Spread Function Photometry on Kepler Data

    Amaro, Rachael Christina; Scolnic, Daniel; Montet, Ben

    2018-01-01

    The Kepler Mission has been able to identify over 5,000 exoplanet candidates using mostly aperture photometry. Despite the impressive number of discoveries, a large portion of Kepler’s data set is neglected due to limitations using aperture photometry on faint sources in crowded fields. We present an alternate method that overcomes those restrictions — Point Spread Function (PSF) photometry. This powerful tool, which is already used in supernova astronomy, was used for the first time on Kepler Full Frame Images, rather than just looking at the standard light curves. We present light curves for stars in our data set and demonstrate that PSF photometry can at least get down to the same photometric precision as aperture photometry. As a check for the robustness of this method, we change small variables (stamp size, interpolation amount, and noise correction) and show that the PSF light curves maintain the same repeatability across all combinations for one of our models. We also present our progress in the next steps of this project, including the creation of a PSF model from the data itself and applying the model across the entire data set at once.

  7. Recordings of mucociliary activity in vivo: benefit of fast Fourier transformation of the photoelectric signal.

    Lindberg, S; Cervin, A; Runer, T; Thomasson, L

    1996-09-01

    Investigations of mucociliary activity in vivo are based on photoelectric recordings of light reflections from the mucosa. The alterations in light intensity produced by the beating cilia are picked up by a photodetector and converted to photoelectric signals. The optimal processing of these signals is not known, but in vitro recordings have been reported to benefit from fast Fourier transformation (FFT) of the signal. The aim of the investigation was to study the effect of FFT for frequency analysis of photoelectric signals originating from an artificial light source simulating mucociliary activity or from sinus or nasal mucosa in vivo, as compared to a conventional method of calculating mucociliary wave frequency, in which each peak in the signal is interpreted as a beat (old method). In the experiments with the artificial light source, the FFT system was superior to the conventional method by a factor of 50 in detecting weak signals. By using FFT signal processing, frequency could be correctly calculated in experiments with a compound signal. In experiments in the rabbit maxillary sinus, the spontaneous variations were greater when signals were processed by FFT. The correlation between the two methods was excellent: r = .92. The increase in mucociliary activity in response to the ciliary stimulant methacholine at a dosage of 0.5 microgram/kg was greater measured with the FFT than with the old method (55.3% +/- 8.3% versus 43.0% +/- 8.2%, p detected. In the human nose, recordings from aluminum foil placed on the nasal dorsum and from the nasal septa mucosa displayed some similarities in the lower frequency spectrum (light, the mean frequency in seven healthy volunteers being 7.8 +/- 1.6 Hz for the human nasal mucosa. It is concluded that the FFT system has greater sensitivity in detecting photoelectric signals derived from the mucociliary system, and that it is also a useful tool for analyzing the contributions of artifacts to the signal.

  8. CALiPER Report 22.1: Photoelectric Performance of LED MR16 Lamps

    None, None

    2015-08-31

    This report looks at the photoelectric performance of the same set of lamps assessed in Report 22, using commercially available transformers and dimmers as well as laboratory power supplies providing either AC or DC. The investigation explores several issues related to the testing and use of MR16 lamps in lighting systems and examines the range of performance that is possible for a given lamp model, based on the system to which it is connected.

  9. Effect of XCOM photoelectric cross-sections on dosimetric quantities calculated with EGSnrc

    Hobeila, F.; Seuntjens, J.P.

    2002-01-01

    The EGSnrc Monte-Carlo code system incorporates improved low energy photon physics such as atomic relaxations and the implementation of bound Compton cross-sections using the impulse approximation. The total cross-section for photoelectric absorption however, still relies on the data by Storm and Israel (S and I). Yet, low energy applications such as brachytherapy (e.g. 125 I) require up-to-date low-energy photoelectric cross-section data. In this paper, we study the dosimetric effects of a simple implementation of NIST XCOM-based photoelectric cross-sections in EGSnrc. This is done by calculating mass energy-absorption coefficients, absorbed dose from point sources, kilovoltage x-ray beams and ion chamber response. In the EGS code system, the PEGS4 routine reads the photoelectric and pair cross-sections for elements from a file (pgspepr.dat) and provides numerical fits for compounds which will be used by EGSnrc. We updated the photoelectric cross-sections of the pgspepr.dat file with the XCOM total photoelectric absorption cross-sections from NIST. After validation of this new implementation, we studied its effects on a number of dosimetrically relevant quantities. Firstly, we calculated mass energy-absorption coefficients by scoring energy transferred in a thin slab of water and air using the DOSRZnrc user code. Secondly, we calculated inverse-square corrected absorbed dose distributions from point sources in water by using an internally developed user code, KERNELph. Thirdly, we studied the differences in free-air ion chamber response calculations. Ion chamber response is defined as the dose to the cavity of an ionization chamber, D gas , positioned with its effective point of measurement at a reference point divided by air-kerma measured free-in-air at the same point. The ion chamber response was calculated using monoenergetic photon beams of energy 10 keV to 200 keV. The comparison of the Storm and Israel photoelectric cross-sections with the XCOM cross

  10. Study on Photoelectric Properties of Composite Films of Graphene/Ti02 Nanorods

    JIN Guo-li

    2017-02-01

    Full Text Available TiOZ nanorods have large specific surface area and the ability of directional transmission electron, based on which can reduce recombination probability of light-generated electrons and holes,and improve the photoelectric conversion efficiency of DSSC. As graphene has low resistivity,good stability and excellent transparency,it can be introduced into anode film to improve the electronic transmission. The TiOZ nanorods were prepared by hydrothermal method,mixed with different quality of graphene. Its length range was 200-300 nm,with a diameter of about 20 nm. The porous graphene/TiOZ nanorods composite film were prepared by using electro- hydrodynamic technique(EHDand compositing TiOZ nanorods with different quality of grapheme. The photoelectric conversion efficiency of the DSSC device prepared with the photo-anode film with graphene mass content of 3 % was 4. 23 %,the photoelectric conversion efficiency increased by 36%,relative to that of no graphene doped TiOZ nanorods photo-anode film.

  11. [A quick algorithm of dynamic spectrum photoelectric pulse wave detection based on LabVIEW].

    Lin, Ling; Li, Na; Li, Gang

    2010-02-01

    Dynamic spectrum (DS) detection is attractive among the numerous noninvasive blood component detection methods because of the elimination of the main interference of the individual discrepancy and measure conditions. DS is a kind of spectrum extracted from the photoelectric pulse wave and closely relative to the artery blood. It can be used in a noninvasive blood component concentration examination. The key issues in DS detection are high detection precision and high operation speed. The precision of measure can be advanced by making use of over-sampling and lock-in amplifying on the pick-up of photoelectric pulse wave in DS detection. In the present paper, the theory expression formula of the over-sampling and lock-in amplifying method was deduced firstly. Then in order to overcome the problems of great data and excessive operation brought on by this technology, a quick algorithm based on LabVIEW and a method of using external C code applied in the pick-up of photoelectric pulse wave were presented. Experimental verification was conducted in the environment of LabVIEW. The results show that by the method pres ented, the speed of operation was promoted rapidly and the data memory was reduced largely.

  12. Titanium dioxide-coated fluorine-doped tin oxide thin films for improving overall photoelectric property

    Li, Bao-jia; Huang, Li-jing; Ren, Nai-fei; Zhou, Ming

    2014-01-01

    Titanium (Ti) layers were deposited by direct current (DC) magnetron sputtering on commercial fluorine-doped tin oxide (FTO) glasses, followed by simultaneous oxidation and annealing treatment in a tubular furnace to prepare titanium dioxide (TiO 2 )/FTO bilayer films. Large and densely arranged grains were observed on all TiO 2 /FTO bilayer films. The presence of TiO 2 tetragonal rutile phase in the TiO 2 /FTO bilayer films was confirmed by X-ray diffraction (XRD) analysis. The results of parameter optimization indicated that the TiO 2 /FTO bilayer film, which was formed by adopting a temperature of 400 °C and an oxygen flow rate of 15 sccm, had the optimal overall photoelectric property with a figure of merit of 2.30 × 10 −2 Ω −1 , higher than 1.78 × 10 −2 Ω −1 for the FTO single-layer film. After coating a 500 nm-thick AZO layer by DC magnetron sputtering on this TiO 2 /FTO bilayer film, the figure of merit of the trilayer film achieved to a higher figure of merit of 3.12 × 10 −2 Ω −1 , indicating further improvement of the overall photoelectric property. This work may provide a scientific basis and reference for improving overall photoelectric property of transparent conducting oxide (TCO) films.

  13. Magnetron sputtering fabrication and photoelectric properties of WSe2 film solar cell device

    Mao, Xu; Zou, Jianpeng; Li, Hongchao; Song, Zhengqi; He, Siru

    2018-06-01

    Tungsten diselenide (WSe2) films with different growing orientations exhibit diverse photoelectric properties. The WSe2 film with C-axis⊥substrate texture has been prepared and applied to thin-film solar cells. W nanofilms with a thickness of 270 nm were deposited onto the Mo bottom electrode and then heat-treated in selenium vapor to synthesize WSe2 films with a thickness of 1 μm. ZnO films were deposited onto WSe2 films to form a P-N junction and ITO films were deposited subsequently as the conductive layer. X-ray diffractometry, scanning electron microscopy and UV-vis-NIR spectro-analysis instrument were employed to analyze the phase composition, optical absorptivity and micromorphology of WSe2 films and the WSe2 solar cell device. WSe2 films exhibit excellent photoelectric performance with an optical absorption coefficient greater than 105 cm-1 across the visible spectrum. The calculated direct and indirect band gap of the WSe2 films is 1.48 eV and 1.25 eV, respectively. With the application of standard glass/Mo/WSe2/ZnO/ITO/Ag device structure, the open-circuit voltage of the battery device is 82 mV. The short-circuit current density is 2.98 mA/cm2 and the filling factor is 0.32. The photoelectric conversion efficiency of the WSe2 film solar cell device is 0.79%.

  14. The design of photoelectric signal processing system for a nuclear magnetic resonance gyroscope based on FPGA

    Zhang, Xian; Zhou, Binquan; Li, Hong; Zhao, Xinghua; Mu, Weiwei; Wu, Wenfeng

    2017-10-01

    Navigation technology is crucial to the national defense and military, which can realize the measurement of orientation, positioning, attitude and speed for moving object. Inertial navigation is not only autonomous, real-time, continuous, hidden, undisturbed but also no time-limited and environment-limited. The gyroscope is the core component of the inertial navigation system, whose precision and size are the bottleneck of the performance. However, nuclear magnetic resonance gyroscope is characteristic of the advantage of high precision and small size. Nuclear magnetic resonance gyroscope can meet the urgent needs of high-tech weapons and equipment development of new generation. This paper mainly designs a set of photoelectric signal processing system for nuclear magnetic resonance gyroscope based on FPGA, which process and control the information of detecting laser .The photoelectric signal with high frequency carrier is demodulated by in-phase and quadrature demodulation method. Finally, the processing system of photoelectric signal can compensate the residual magnetism of the shielding barrel and provide the information of nuclear magnetic resonance gyroscope angular velocity.

  15. Photoelectric conversion properties of electrochemically codeposited graphene oxide–ZnO nanocomposite films

    Li, Yiming; Wang, Dian; Li, Wenyou [School of Materials Science and Engineering, Tongji University, Shanghai, 201804 (China); He, Yunqiu, E-mail: heyunqiu@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai, 201804 (China); Key Laboratory of Advanced Civil Engineering Materials, Ministry of Education, Shanghai, 201804 (China)

    2015-11-05

    Graphene oxide (GO)–ZnO nanocomposite films were synthesized on Fluorine doped Tin Oxide (FTO) coated glasses by electrochemical codeposition. The films have a laminated architecture with GO and ZnO alternate layers arranged basically parallel to the substrate. The structures of the composites were characterized using XRD, FE-SEM, FT-IR, XPS, Raman, UV–visible, and electrochemical cyclic voltammetry analyses. The results showed that by increasing Zn:C ratio of the suspensions, there is a series of structural evolutions of the composites, and the percentages of the C–O bonds of GO in the composites decreased. The decreased C–O bonds of GO indicate an increase in the reduction degree of GO, with which its energy gap varies from 1.99 eV to 0.89 eV. Moreover, the energy levels of GO and ZnO in the composites were determined. The results of photoelectrochemical measurements of the films indicated the feasibility of using GO in photoelectric conversion as photoabsorbers. A preliminary study on the relationship between the changes in the photocurrent and the structure of the films has provided clues for further studies on improving the photoelectric conversion properties. - Highlights: • Graphene Oxide–ZnO nanocomposite films were obtained by electrochemical codeposition. • The structure of GO varies with the Zn:C ratio of the depositing suspensions. • The feasibility of using GO as photoabsorbers for photoelectric conversion was verified.

  16. Titanium dioxide-coated fluorine-doped tin oxide thin films for improving overall photoelectric property

    Li, Bao-jia, E-mail: bjia_li@126.com [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Huang, Li-jing [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Ren, Nai-fei [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Ming [The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-01-30

    Titanium (Ti) layers were deposited by direct current (DC) magnetron sputtering on commercial fluorine-doped tin oxide (FTO) glasses, followed by simultaneous oxidation and annealing treatment in a tubular furnace to prepare titanium dioxide (TiO{sub 2})/FTO bilayer films. Large and densely arranged grains were observed on all TiO{sub 2}/FTO bilayer films. The presence of TiO{sub 2} tetragonal rutile phase in the TiO{sub 2}/FTO bilayer films was confirmed by X-ray diffraction (XRD) analysis. The results of parameter optimization indicated that the TiO{sub 2}/FTO bilayer film, which was formed by adopting a temperature of 400 °C and an oxygen flow rate of 15 sccm, had the optimal overall photoelectric property with a figure of merit of 2.30 × 10{sup −2} Ω{sup −1}, higher than 1.78 × 10{sup −2} Ω{sup −1} for the FTO single-layer film. After coating a 500 nm-thick AZO layer by DC magnetron sputtering on this TiO{sub 2}/FTO bilayer film, the figure of merit of the trilayer film achieved to a higher figure of merit of 3.12 × 10{sup −2} Ω{sup −1}, indicating further improvement of the overall photoelectric property. This work may provide a scientific basis and reference for improving overall photoelectric property of transparent conducting oxide (TCO) films.

  17. Precision Photometry and Astrometry from Pan-STARRS

    Magnier, Eugene A.; Pan-STARRS Team

    2018-01-01

    The Pan-STARRS 3pi Survey has been calibrated with excellent precision for both astrometry and photometry. The Pan-STARRS Data Release 1, opened to the public on 2016 Dec 16, provides photometry in 5 well-calibrated, well-defined bandpasses (grizy) astrometrically registered to the Gaia frame. Comparisons with other surveys illustrate the high quality of the calibration and provide tests of remaining systematic errors in both Pan-STARRS and those external surveys. With photometry and astrometry of roughly 3 billion astronomical objects, the Pan-STARRS DR1 has substantial overlap with Gaia, SDSS, 2MASS and other surveys. I will discuss the astrometric tie between Pan-STARRS DR1 and Gaia and show comparisons between Pan-STARRS and other large-scale surveys.

  18. A Practical Guide to Lightcurve Photometry and Analysis

    Warner, Brian D

    2006-01-01

    A Practical Guide to Lightcurve Photometry and Analysis provides, for those with access to even a modest telescope and CCD camera, all the information needed to take part in the scientific study of asteroids and variable stars. Using commercially available equipment, amateur astronomers can determine the rotation rate, size, and shape of asteroids. Similarly, it is possible to discover the size, temperature, and orbits of stars in binary systems by using this powerful technique. A Practical Guide to Lightcurve Photometry and Analysis contains all the material needed for readers to understand the theory, and avoid the practical pitfalls of lightcurve photometry. Detailed examples are given for obtaining data, and of course for the exciting and rewarding task of analyzing the data to determine the physical properties of the object. Any college student or amateur astronomer who wants to go beyond mere imaging with a CCD camera and enter the challenging world of "real science" via the lightcurves of asteroids and...

  19. Jonckheere Double Star Photometry – Part X: Hercules

    Knapp, Wilfried

    2018-04-01

    If any double star discoverer is in urgent need of photometry then it is Jonckheere. There are over 3000 Jonckheere objects listed in the WDS catalog and a good part of them with magnitudes obviously far too bright. This report covers 28 of the in total 82 Jonckheere objects in the constellation Hercules selected by a quick WDS data check for being potentially listed with questionable magnitudes. At least one image per object was taken with V-filter to allow for visual magnitude measurement by differential photometry. All objects were additionally checked for common proper motion and two qualify indeed as potential CPM pairs.

  20. UBV-photometry of flare stars in pleiades

    Chavushyan, O.S.; Garibdzhanyan, A.T.

    1975-01-01

    The results are presented of UBV-photometry of 283 flare stars at the minimum of brightness in the Pleiad region. A new method has been developed and used of taking into account the background in photographic UBV-photometry with an iris microphotometer. The data obtained indicate that the flare Pleiad stars are located on both sides of the main sequence in the light-luminosity (V,B-V) diagram, while in the (U-B,B-V) diagram they are largely located above the main sequence

  1. Galileo Photometry of Asteroid 951 Gaspra

    Helfenstein, P.; Veverka, J.; Thomas, P.C.; Simonelli, D.P.; Lee, P.; Klaasen, K.; Johnson, T.V.; Breneman, H.; Head, J.W.; Murchie, S.; Fanale, F.; Robinson, M.; Clark, B.; Granahan, J.; Garbeil, H.; McEwen, A.S.; Kirk, R.L.; Davies, M.; Neukum, G.; Mottola, S.; Wagner, R.; Belton, M.; Chapman, C.; Pilcher, C.

    1994-01-01

    Galileo images of Gaspra make it possible for the first time to determine a main-belt asteroid's photometric properties accurately by providing surface-resolved coverage over a wide range of incidence and emission angles and by extending the phase angle coverage to phases not observable from Earth. We combine Earth-based telescopic photometry over phase angles 2?? ??? ?? ??? 25?? with Galileo whole-disk and disk-resolved data at 33?? ??? ?? ??? 51?? to derive average global photometric properties in terms of Hapke's photometric model. The microscopic texture and particle phase-function behavior of Gaspra's surface are remarkably like those of other airless rocky bodies such as the Moon. The macroscopic surface roughness parameter, ??̄ = 29??, is slightly larger than that reported for typical lunar materials. The particle single scattering albedo, ??́0 = 0.36 ?? 0.07, is significantly larger than for lunar materials, and the opposition surge amplitude, B0 = 1.63 ?? 0.07, is correspondingly smaller. We determine a visual geometric albedo pv = 0.22 ?? 0.06 for Gaspra, in close agreement with pv = 0.22 ?? 0.03 estimated from Earth-based observations. Gaspra's phase integral is 0.47, and the bolometric Bond albedo is estimated to be 0.12 ?? 0.03. An albedo map derived by correcting Galileo images with our average global photometric function reveals subdued albedo contrasts of ??10% or less over Gaspra's northern hemisphere. Several independent classification algorithms confirm the subtle spectral heterogeneity reported earlier (S. Mottola, M. DiMartino, M. Gonano-Beurer, H. Hoffman, and G. Neukum, 1993, Asteroids, Comets, Meteors, pp. 421-424; M. J. S. Belton et al., 1992, Science 257, 1647-1652). Whole-disk colors (0.41 ??? ?? ??? 0.99 ??m) vary systematically with longitude by about ??5%, but color differences as large as 30% occur locally. Colors vary continuously between end-member materials whose areal distribution correlates with regional topography. Infrared

  2. BVRI SURFACE PHOTOMETRY OF ISOLATED GALAXY TRIPLETS

    Hernandez-Toledo, H. M.; Mendez-Hernandez, H.; Aceves, H.; OlguIn, L.

    2011-01-01

    relative to an isolated galaxy control sample is also interpreted as consistent with interactions in physically bounded aggregates. Our results lead us to suggest that non-negligible populations of physical triplets might be found in complete and well-observed samples. We provide individual mosaics for the 54 galaxies containing (1) logarithmic-scaled R-band images, (2) R-band sharp/filtered images, (3) (B - I) color index maps, (4) RGB images from the SDSS database, (5) co-added J + H + K images generated from the 2MASS archives that were also sharp/filtered, and (6) ε, position angle radial profiles from a surface photometry analysis of (a) the R band and (b) the co-added near-infrared images, all used for the present analysis.

  3. The High Road to Astronomical Photometric Precision : Differential Photometry

    Milone, E. F.; Pel, Jan Willem

    2011-01-01

    Differential photometry offers the most precise method for measuring the brightness of astronomical objects. We attempt to demonstrate why this should be the case, and then describe how well it has been done through a review of the application of differential techniques from the earliest visual

  4. Photometry and models of eight near-Earth asteroids

    Kaasalainen, M.; Pravec, Petr; Krugly, Yu. N.; Kotková, Lenka; Torppa, J.; Virtanen, J.; Kaasalainen, S.; Erikson, A.; Nathues, A.; Ďurech, J.; Wolf, M.; Lagerros, J. S. V.; Lindgren, M.; Lagerkvist, C.-I.; Koff, R.; Davies, J.; Mann, R.; Kušnirák, Peter; Gaftonyuk, N. M.; Shevchenko, V. G.; Chiorny, V. G.; Belskaya, I. N.

    2004-01-01

    Roč. 167, č. 1 (2004), s. 178-196 ISSN 0019-1035 R&D Projects: GA AV ČR IAA3003204; GA ČR GA205/99/0255 Institutional research plan: CEZ:AV0Z1003909 Keywords : asteroids * rotation * photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.074, year: 2004

  5. 3-color photometry of a sunspot using speckle masking techniques

    Wiehr, E.; Sütterlin, P.

    1998-01-01

    A three-colour photometry is used to deduce the temperature of sunspot fine-structures. Using the Speckle-Masking method for image restoration, the resulting images (one per colour and burst) have a spatial resolution only limited by the telescope's aperture, i.e. 95km (blue), 145 km (red) and

  6. The possibilities of CCD photometry of optical afterglows of GRBs

    Šimon, Vojtěch; Polášek, Cyril; Jelínek, M.; Hudec, René; Štrobl, Jan

    -, č. 125 (2010), s. 24-28 ISSN 1801-5964. [Conference on Variable Stars Research /41./. Prague, 27.11.2009-29.11.2009] Institutional research plan: CEZ:AV0Z10030501 Keywords : gamma-ray bursts * optical afterglows * CCD photometry Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  7. TNO Photometry and Spectroscopy at ESO and Calar Alto

    Boehnhardt, H.; Sekiguchi, T.; Vair, M.; Hainaut, O.; Delahodde, C.; West, R. M.; Tozzi, G. P.; Barrera, L.; Birkle, K.; Watanabe, J.; Meech, K.

    New photometry and spectroscopy of Transneptunian objects (TNO) has been obtained at ESO (VLT+FORS1, NTT+SOFI) and the Calar Alto (3.5m+MOSCA) observatory. BVRI photometry of more than 10 objects confirms the general colour-colour distribution of TNOs found previously. Quasi-simultaneous spectroscopy in the visible wavelength range of 5 TNOs did not reveal any spectral signature apart from the spetral gradients which are in agreement with the broadband colours. JHK filter photometry of 3 objects indicates that the reddening may only occur in the near-IR at least in some cases. Using new observations from the ESO VLT the lightcurve, colours and spectrum of 1996TO66 are investigated: the rotation period of 6.25h is confirmed, also the change in the lightcurve between 1997 and 1998 which indicates an exceptional behaviour in this object (temporary cometary activity ?). The 1999 photometry and spectroscopy in the visible revealed solar colours, no reddening and no spectral features. V-R colour changes over the rotation phase are not found. This works is done in colaboration with:

  8. Near-infrared photometry of bright elliptical galaxies

    Peletier, R. F.; Valentijn, E. A.; Jameson, R. F.

    High-quality visual-infrared color profiles have been determined for elliptical galaxies for the first time. Surface photometry in J and K is presented for 12 bright elliptical galaxies, and the results have been combined with CCD data in visual passbands. It is shown that the galaxies become bluer

  9. CCD photometry of apparent dwarf galaxies in Fornax

    Phillipps, S.; Grimley, P.L.; Disney, M.J.; Cawson, M.G.M.; Kibblewhite, E.J.

    1986-01-01

    Blue and red CCD surface photometry of two apparent dwarf galaxies in the Fornax cluster region is presented. Luminosity profiles are derived and their form discussed. The fainter galaxy resembles an archetypal diffuse dwarf elliptical but the brighter of the pair is either an unusual red dwarf or a background galaxy in chance juxtaposition. (author)

  10. Instability of a double layer and initiation of a photoelectric gas discharge by UV radiation

    Meshalkin, E.A.

    1991-01-01

    At the present time there is no theory or systematic experiments for the conversion of the energy of vacuum uv radiation into current energy in connection with the photoelectric effect in gases. The aim in this work was to study the process by which an SCL is established and to obtain a gas discharge associated with photoemission (a photoelectric gas discharge), similar to the gas discharge in thermal-emission converters, in order to transform optical energy into electrical current. The development of a space-charge layer (SCL) is studied when a metallic target in air or nitrogen at a pressure in the range 10 -3 -10 torr is subjected to UV radiation. A laser plasma was used as the source of the UV radiation, modulated in intensity at a frequency of 75 MHz. It was found that after a period of development in the course of which the potential difference across the SCL can reach 185 V, it drops abruptly. This effect is due to an instability of the SCL which arises because the pressure of the electron gas in the background plasma exceeds the confining pressure of the electric field which penetrates from SCL into the plasma. A photoelectric arc discharge was observed in which the energy of the UV radiation was converted into current energy with an efficiency ∼ 1%. The current was found to be 3.1 A and the power in the load was 10W. Because of the threshold for the occurrence of the instability in the SCL, the potential drop across the SCL could be completely modulated at a frequency of 75 MHz. The amplitude of the HF current reached 0.3 A

  11. Measurements of Photoelectric Yield and Physical Properties of Individual Lunar Dust Grains

    Abbas, M. M.; Tankosic, D.; Craven, P. D.; Spann, J. F.; LeClair, A.; West, F. A.; Taylor, L.; Hoover, R.

    2005-01-01

    Micron size dust grains levitated and transported on the lunar surface constitute a major problem for the robotic and human habitat missions for the Moon. It is well known since the Apollo missions that the lunar surface is covered with a thick layer of micron/sub-micron size dust grains. Transient dust clouds over the lunar horizon were observed by experiments during the Apollo 17 mission. Theoretical models suggest that the dust grains on the lunar surface are charged by the solar UV radiation as well as the solar wind. Even without any physical activity, the dust grains are levitated by electrostatic fields and transported away from the surface in the near vacuum environment of the Moon. The current dust charging and the levitation models, however, do not fully explain the observed phenomena. Since the abundance of dust on the Moon's surface with its observed adhesive characteristics is believed to have a severe impact on the human habitat and the lifetime and operations of a variety of equipment, it is necessary to investigate the phenomena and the charging properties of the lunar dust in order to develop appropriate mitigating strategies. We will present results of some recent laboratory experiments on individual micro/sub-micron size dust grains levitated in electrodynamic balance in simulated space environments. The experiments involve photoelectric emission measurements of individual micron size lunar dust grains illuminated with UV radiation in the 120-160 nm wavelength range. The photoelectric yields are required to determine the charging properties of lunar dust illuminated by solar UV radiation. We will present some recent results of laboratory measurement of the photoelectric yields and the physical properties of individual micron size dust grains from the Apollo and Luna-24 sample returns as well as the JSC-1 lunar simulants.

  12. Reform and practice for photoelectric specialty experimental teaching based on virtual simulation experiment platform

    Ye, Yan; Lv, Qingsong; Wu, Maocheng; Xu, Yishen; Gu, Jihua

    2017-08-01

    In view of some problems about the traditional photoelectric specialty experimental teaching process, such as separation of theoretical teaching and practical teaching, immobilization of experimental teaching contents, low quality of experiments and no obvious effect, we explored and practiced a new experimental teaching model of "theoretical teaching, virtual simulation and physical experiment", which combined the characteristics of photoelectric information science and engineering major and the essential requirements of engineering innovation talents cultivation. The virtual simulation experiment platform has many advantages, such as high performance-to-price ratio, easy operation and open experimental process, which makes virtual simulation combine physical experiment, complete each other with virtual for practical. After the users log into the virtual simulation experimental platform, they will first study the contents of the experiment, clarify the purpose and requirements of the experiment, master the method of using the instrument and the relevant notes, and then use the experimental instruments provided by the platform to build the corresponding experimental system. Once the experimenter's optical path is set incorrectly or the instrument parameters are set incorrectly, the error or warning message will be automatically triggered, and the reference information will be given instructing the student to complete the correct experimental operation. The results of our practice in recent years show that the teaching reform of the photoelectric specialty experiments has not only brought great convenience to the experimental teaching management, broadened the students' thinking and vision, enhanced the students' experimental skills and comprehensive qualities, but also made the students participate in the experiment with their enthusiasm. During the construction of experiment programs, the students' engineering practical ability and independent innovation awareness

  13. Exploration on practice teaching reform of Photoelectric Image Processing course under applied transformation

    Cao, Binfang; Li, Xiaoqin; Liu, Changqing; Li, Jianqi

    2017-08-01

    With the further applied transformation of local colleges, teachers are urgently needed to make corresponding changes in the teaching content and methods from different courses. The article discusses practice teaching reform of the Photoelectric Image Processing course in the Optoelectronic Information Science and Engineering major. The Digital Signal Processing (DSP) platform is introduced to the experimental teaching. It will mobilize and inspire students and also enhance their learning motivation and innovation through specific examples. The course via teaching practice process has become the most popular course among students, which will further drive students' enthusiasm and confidence to participate in all kinds of electronic competitions.

  14. Gamma radiation effects on photorefractive and photoelectric properties of lithium niobate crystals

    Vartanyan, Eh.S.; Ovsepyan, R.K.; Pogosyan, A.R.; Timofeev, A.L.

    1984-08-01

    Investigations into the gamma radiation effect on the photorefractive aned photoelectric properties of lithium niobate crystals have been carried out for the first time. Gamma irradiation has been found to lead to an increase in the photorefractive sensitivity. The effect of optical decoloration has been discovered for the first time along with photorelaxation currents resulting from radiation center decay under the action of light. It has been shown that an increase of photorefractive sensitivity in gamma-irradiated lithium niobate crystals is caused by a new photorefraction mechanism - photorelaxation currents.

  15. ANALYSIS OF SOLAR POWER STATION SCHEMES ON PHOTOELECTRIC MODULES FOR ELECTRIC CARS CHARGING STATIONS

    A. Hnatov

    2017-12-01

    Full Text Available The analysis of existing schemes for building solar power stations on photoelectric modules with the revealing of their operation principles and functionality has been conducted. The specified technical characteristics of each of the analyzed schemes are given. The structural scheme of the solar charging station for electric cars with determining its functional capabilities and operation features is proposed. The practical application of this scheme will help to reduce the dependence on the general electric power supply network and will create conditions for its total rejection.

  16. Measurement of K-shell photoelectric cross-sections for some characteristic x-rays

    Allawadhi, K L; Sood, B S

    1976-03-05

    Because of the non-availability of clean and strong low energy photon sources, external conversion x-rays in various suitable targets have been produced and successfully used to measure relative K shell photoelectric cross-sections in Y for incident energies 17.781, 22.581, 23.618, 25.770, 29.208, 35.478, 41.006, and 43.949 keV in a double reflection geometry experiment. A brief outline of the procedure of measurement and the results obtained are given. (auth)

  17. Relative L-shell photoelectric cross-section measurements in W, Pb and U

    Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1981-06-01

    Measurements of L-shell photoelectric cross sections in W, Pb and U at K X-ray energies of Nb, Mo, Ag, In, Sn, I, Ba, Ce, Gd and Er have been made. The method yields relative cross sections and is, therefore, simpler and more accurate than those giving absolute values. The problems arising due to the non-monochromatic character of incident and emitted X-rays in the targets have been investigated. The present results show a fairly good agreement with the theoretical predicitions.

  18. uvby and Hβ photometry of the open cluster IC 4996

    Alfaro, E.J.; Delgado, A.J.; Garcia-Pelayo, J.M.; Garrido, R.; Saez, M.

    1985-01-01

    Photoelectric uvby and Hβ observations have been obtained for 15 stars in the field of the open cluster IC 4996. An average colour excess of E(b-y)=0.473 is estimated for six observed members of the cluster, in good agreement with previous results. A comparison between the β-Msub(v) calibrations given by Crawford and by Eggen suggests that the first one takes better into account the evolutionary effects on the Hβ index. We have calculated a true distance modulus of 11.43 and an age of 7.5x10 6 years

  19. The TERMS Project: Improved Orbital Parameters and Photometry of HD168443 and the Photometry Pipeline

    Pilyavsky, Genady; Mahadevan, S.; Kane, S. R.; Howard, A. W.; Ciardi, D. R.; de Pree, C.; Dragomir, D.; Fischer, D.; Henry, G. W.; Jensen, E. L. N.; Laughlin, G.; Marlowe, H.; Rabus, M.; von Braun, K.; Wright, J. T.; Wang, X.

    2012-01-01

    The discovery of transiting planets around bright stars holds the potential to greatly enhance our understanding of planetary atmospheres. The Transit Ephemeris Refinement and Monitoring Survey (TERMS) project focuses on updating the ephemerides of known exoplanets, put tighter constraints on the orbital parameters and shrink the large errors on the predicted transit windows, enabling photometric monitoring to search for a transit signature. Here, we present the revised orbital parameters and the photometric coverage during a predicted transit window of HD168443b, a massive planet orbiting the bright star HD 168443 (V = 6.92) with a period of 58.11 days. The high eccentricity of the planetary orbit (e = 0.53) significantly enhances the a-priori transit probability (3.7%) from what is expected for a circular orbit (2.5%). The transit ephemeris was updated using refined orbital parameters from additional Keck-HIRES radial velocities. The photometry obtained at the 1 m telescope in Cerro Tololo Inter-American Observatory (CTIO) and the T8 0.8 m Automated Photometric Telescope (APT) at Fairborn Observatory achieved the necessary millimag precision. The expected change in flux (0.5%) for HD168443 was not observed during the predicted transit window, thus allowing us to rule out the transit and put tighter constrains on the orbital inclination of HD168443b. Additionally, we present the software used to analyze the CTIO data. Developed by the TERMS team, this IDL based package is a fast, precise, and easy to use program which has eliminated the need for external software and command line prompts by utilizing the functionality of a graphical user interface (GUI).

  20. Photoelectric method for determination of the moment of formation of an anodic spot

    Barinov, V.N.; Goncharov, V.K.; Smirnov, A.V.

    1986-01-01

    In studying the problem of the effect of the amplitude and form of discharge current pulses on the time for transition from a diffuse discharge form to a contracted one and on the value of the threshold current I /SUB As/ for formation of an anodic spot, the authors used a photoelectric method for determination of the moment of appearance of the anodic spot based on determination of the spectral composition of the plasma at different moments of time after the beginning of discharge initiation. The photoelectric method can be used in studying emission processes on a cathode and also in those cases where both electrodes are made of the same material. An example shows synchronous oscillograms of I /SUB p/ (tau) and J /SUB i/ (tau) for copper electrodes. It is evident that during transition of the discharge to a contracted form with an anodic spot there was a sharp increase of the intensity of deexcitation of the ionic copper line. At the moment of extinction of the anodic spot, the amplitude values of J /SUB i/ (tau) corresponded to a level characteristic of the diffuse form of arc burning

  1. Synthesis of Water-Soluble Antimony Sulfide Quantum Dots and Their Photoelectric Properties.

    Zhu, Jiang; Yan, Xuelian; Cheng, Jiang

    2018-01-15

    Antimony sulfide (Sb 2 S 3 ) has been applied in photoelectric devices for a long time. However, there was lack of information about Sb 2 S 3 quantum dots (QDs) because of the synthesis difficulties. To fill this vacancy, water-soluble Sb 2 S 3 QDs were prepared by hot injection using hexadecyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) mixture as anionic-cationic surfactant, alkanol amide (DEA) as stabilizer, and ethylenediaminetetraacetic acid (EDTA) as dispersant. Photoelectric properties including absorbing and emission were characterized by UV-Vis-IR spectrophotometer and photoluminescence (PL) spectroscopic technique. An intensive PL emission at 880 nm was found, indicating Sb 2 S 3 QDs have good prospects in near-infrared LED and near-infrared laser application. Sb 2 S 3 QD thin films were prepared by self-assembly growth and then annealed in argon or selenium vapor. Their band gaps (E g s) were calculated according to transmittance spectra. The E g of Sb 2 S 3 QD thin film has been found to be tunable from 1.82 to 1.09 eV via annealing or selenylation, demonstrating the good prospects in photovoltaic application.

  2. Electron track reconstruction and improved modulation for photoelectric X-ray polarimetry

    Li, Tenglin [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Zeng, Ming, E-mail: zengming@tsinghua.edu.cn [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Feng, Hua [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Cang, Jirong [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Li, Hong; Zhang, Heng [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Center for Astrophysics, Tsinghua University, Beijing 100084 (China); Zeng, Zhi; Cheng, Jianping; Ma, Hao; Liu, Yinong [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China)

    2017-06-21

    The key to photoelectric X-ray polarimetry is the determination of the emission direction of photoelectrons. Because of the low mass of an electron, the ionisation trajectory is not straight and the useful information needed for polarimetry is stored mostly in the initial part of the track where less energy is deposited. We present a new algorithm, based on the shortest path problem in graph theory, to reconstruct the 2D electron track from the measured image that is blurred due to transversal diffusion along drift and multiplication in the gas chamber. Compared with previous methods based on moment analysis, this algorithm allows us to identify the photoelectric interaction point more accurately and precisely for complicated tracks resulting from high energy photons or low pressure chambers. This leads to a better position resolution and a higher degree of modulation toward high energy X-rays. The new algorithm is justified using simulations and measurements with the gas pixel detector (GPD), and it should also work for other polarimetric techniques such as a time projection chamber (TPC). As the improvement is restricted in the high energy band, this new algorithm shows limited improvement for the sensitivity of GPD polarimeters, but it may have a larger potential for low-pressure TPC polarimeters.

  3. Electrical and photoelectrical characteristic investigation of a new generation photodiode based on bromothymol blue dye

    Imer, A Gencer; Korkut, A; Tombak, A

    2016-01-01

    Bromothymol blue (BTB) with the molecular formula of C 27 H 28 Br 2 O 5 S was grown onto p-Si substrate to fabricate heterojunction by spin coating technique. The current voltage ( I-V ) measurements of diode were carried out in dark and under different illumination intensity at room temperature. The photoelectrical properties of heterojunction based on BTB were investigated using the illumination intensity dependent I-V data. The results showed that photo current of diode increases with the increase in light intensity. Also, the electrical parameters of device were determined via I-V, and capacitance- voltage ( C-V ), conductance-voltage ( G-V ) measurements at different frequencies. It is observed that the excess capacitance is created at low frequencies due to the contribution of interface states charge which can follow the alternative current signal to capacitance. It is stated that, both the electrical and photoelectrical parameters of diode can be changed, and also the performance of the device could be affected by the organic thin film interlayer. (paper)

  4. Photoelectric Properties of Si Doping Superlattice Structure on 6H-SiC(0001).

    Li, Lianbi; Zang, Yuan; Hu, Jichao; Lin, Shenghuang; Chen, Zhiming

    2017-05-25

    The energy-band structure and visible photoelectric properties of a p/n-Si doping superlattice structure (DSL) on 6H-SiC were simulated by Silvaco-TCAD. The,n the Si-DSL structures with 40 nm-p-Si/50 nm-n-Si multilayers were successfully prepared on 6H-SiC(0001) Si-face by chemical vapor deposition. TEM characterizations of the p/n-Si DSL confirmed the epitaxial growth of the Si films with preferred orientation and the misfit dislocations with a Burgers vector of 1/3 at the p-Si/n-Si interface. The device had an obvious rectifying behavior, and the turn-on voltage was about 1.2 V. Under the visible illumination of 0.6 W/cm², the device demonstrated a significant photoelectric response with a photocurrent density of 2.1 mA/cm². Visible light operation of the Si-DSL/6H-SiC heterostructure was realized for the first time.

  5. Photoelectric Properties of Si Doping Superlattice Structure on 6H-SiC(0001

    Lianbi Li

    2017-05-01

    Full Text Available The energy-band structure and visible photoelectric properties of a p/n-Si doping superlattice structure (DSL on 6H-SiC were simulated by Silvaco-TCAD. The,n the Si-DSL structures with 40 nm-p-Si/50 nm-n-Si multilayers were successfully prepared on 6H-SiC(0001 Si-face by chemical vapor deposition. TEM characterizations of the p/n-Si DSL confirmed the epitaxial growth of the Si films with preferred orientation and the misfit dislocations with a Burgers vector of 1/3 <21-1> at the p-Si/n-Si interface. The device had an obvious rectifying behavior, and the turn-on voltage was about 1.2 V. Under the visible illumination of 0.6 W/cm2, the device demonstrated a significant photoelectric response with a photocurrent density of 2.1 mA/cm2. Visible light operation of the Si-DSL/6H-SiC heterostructure was realized for the first time.

  6. Experimental investigation on photoelectric properties of ZAO thin film deposited on flexible substrate by magnetron sputtering

    Hao, Ming [School of Mechanical Engineering and Automation, Northeastern University, 3-11 WenHua Rd., 319#, Shenyang, 110004 (China); Liu, Kun, E-mail: kliu@mail.neu.edu.cn [School of Mechanical Engineering and Automation, Northeastern University, 3-11 WenHua Rd., 319#, Shenyang, 110004 (China); Liu, Xinghua [Hubei Aerospace Industry Technology Academe Special Vehicle Technology Center, Wuhan (China); Wang, Dongyang; Ba, Dechun; Xie, Yuanhua; Du, Guangyu; Ba, Yaoshuai [School of Mechanical Engineering and Automation, Northeastern University, 3-11 WenHua Rd., 319#, Shenyang, 110004 (China)

    2016-12-01

    Highlights: • ZAO thin films were deposited on PET substrate. • A set of experimental parameters were systematically investigated. • Change rule of film photoelectric properties was obtained. • ZAO films with optimal properties were obtained at our working conditions. - Abstract: Transparent conductive ZAO (Zinc Aluminum Oxide) films on flexible substrates have a great potential for low-cost mass-production solar cells. ZAO thin films were achieved on flexible PET (polyethylene terephthalate) substrates by RF magnetron sputtering technology. The surface morphology and element content, the transmittance and the sheet resistance of the films were measured to determine the optical process parameters. The results show that the ZAO thin film shows the best parameters in terms of photoelectric performance including sputtering power, working pressure, sputtering time, substrate temperature (100 W, 1.5 Pa, 60 min, 125 °C). The sheet resistance of 510 Ω and transmittance in visible region of 92% were obtained after characterization. Surface morphology was uniform and compact with a good crystal grain.

  7. Experimental investigation on photoelectric properties of ZAO thin film deposited on flexible substrate by magnetron sputtering

    Hao, Ming; Liu, Kun; Liu, Xinghua; Wang, Dongyang; Ba, Dechun; Xie, Yuanhua; Du, Guangyu; Ba, Yaoshuai

    2016-01-01

    Highlights: • ZAO thin films were deposited on PET substrate. • A set of experimental parameters were systematically investigated. • Change rule of film photoelectric properties was obtained. • ZAO films with optimal properties were obtained at our working conditions. - Abstract: Transparent conductive ZAO (Zinc Aluminum Oxide) films on flexible substrates have a great potential for low-cost mass-production solar cells. ZAO thin films were achieved on flexible PET (polyethylene terephthalate) substrates by RF magnetron sputtering technology. The surface morphology and element content, the transmittance and the sheet resistance of the films were measured to determine the optical process parameters. The results show that the ZAO thin film shows the best parameters in terms of photoelectric performance including sputtering power, working pressure, sputtering time, substrate temperature (100 W, 1.5 Pa, 60 min, 125 °C). The sheet resistance of 510 Ω and transmittance in visible region of 92% were obtained after characterization. Surface morphology was uniform and compact with a good crystal grain.

  8. The effect of Phet Simulation media for physics teacher candidate understanding on photoelectric effect concept

    Supurwoko Supurwoko

    2017-02-01

    Full Text Available Indonesian new Curriculum for senior high school students required student-centered learning. One of the curriculum implementation constraint was the difficulty of providing learning media. PhET simulations media is one of the options that can help implementation of new curriculum on learning. However, the use of this media in Indonesia still needs to be studied comprehensively. The learning was conducted on students of physics education Study Program in sebelas maret university in 2013. The sample consisted of 62 students that was taking quantum physics course. The method that was used in the research was descriptive qualitative.  The method that was used in learning was demonstration’s method that used PhET media and accompanied by a question and answer and groups discussion. The data was collected using multiple choice test and interview through email. We found that any students still did not understand about photoelectric effect concept. They were confused when asked about the thick material and cross section of the targets as related with the regardless of electrons in the photoelectric effect event. Other than that, the concept of the waves as a particle and its relation with the kinetic energy of the electrons was not understood by most students.

  9. Astrometry, Radial Velocity, and Photometry: The HD 128311 System Remixed with Data from HST, HET, and APT

    McArthur, Barbara. E.; Benedict, G. Fritz; Henry, Gregory W.; Hatzes, Artie; Cochran, William D.; Harrison, Tom E.; Johns-Krull, Chris; Nelan, Ed

    2014-11-01

    We have used high-cadence radial velocity measurements from the Hobby-Eberly Telescope with published velocities from the Lick 3 m Shane Telescope, combined with astrometric data from the Hubble Space Telescope (HST) Fine Guidance Sensors to refine the orbital parameters of the HD 128311 system, and determine an inclination of 55.°95 ± 14.°55 and true mass of 3.789 +0.924 -0.432 M JUP for HD 128311 c. The combined radial velocity data also reveal a short period signal which could indicate a third planet in the system with an Msin i of 0.133 ± 0.005 M JUP or stellar phenomena. Photometry from the T12 0.8 m automatic photometric telescope at the Fairborn Observatory and HST are used to determine a photometric period close to, but not within the errors of the radial velocity signal. We performed a cross-correlation bisector analysis of the radial velocity data to look for correlations with the photometric period and found none. Dynamical integrations of the proposed system show long-term stability with the new orbital parameters of over 10 million years. Our new orbital elements do not support the claims of HD 128311 b and c being in mean motion resonance. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. Based on observations obtained with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen, and observations with T12 0.8 m automatic photoelectric telescope (APT) at Fairborn Observatory.

  10. Optical and photoelectric properties of nanolamellar structures obtained by thermal annealing of InSe plates in Zn vapours

    Untila, Dumitru; Evtodiev, Igor [Faculty of Physics and Engineering, Moldova State University, Chisinau (Moldova, Republic of); Ghitu Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Chisinau (Moldova, Republic of); Caraman, Iuliana [Engineering Department ' ' Vasile Alecsandri' ' , University of Bacau (Romania); Spalatu, Nicolae [Department of Materials Science, Tallinn University of Technology (Estonia); Dmitroglo, Liliana; Caraman, Mihail [Faculty of Physics and Engineering, Moldova State University, Chisinau (Moldova, Republic of)

    2018-02-15

    The structural, optical and photoelectric properties of InSe crystals grown by Bridgman-Stockbarger method and ZnSe/InSe structures obtained on InSe by thermal annealing in Zn vapours are studied in this paper. The study of structural properties confirms that ZnSe compound is formed. The analysis of photoelectric properties reveal that both the ZnSe-InSe composite layer and the composite/InSe heterojunction are photosensitive in the VIS-NIR spectral region. (copyright 2018 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Copernicus spectra and infrared photometry of 42 Orionis

    Johnson, H.M.; Snow, T.P. Jr.; Gehrz, R.D.; Hackwell, J.A.

    1977-01-01

    The Orion sword star 42 Ori is embedded in a nebula north of and separated from the Orion nebula. The B1 V star is probably normal. Other members of the multiple remain poorly defined, and the nebula may exhibit some peculiarities that may depend on them. Copernicus ultraviolet spectra of the star are described here, especially in the form of tables of wavelength identifications. The properties of the interstellar material in the line of sight are also discussed. We present infrared photometry which suggests that 3 less than or equal to R less than or equal to 3.5 for the interstellar matter in the direction of 42 Ori. The IR photometry provides no evidence for companion stellar or circumstellar components

  12. A spatially resolved study of photoelectric heating and [C II] cooling in the LMC Comparison with dust emission as seen by SAGE

    Rubin, D.; Hony, S.; Madden, S. C.; Tielens, A. G. G. M.; Meixner, M.; Indebetouw, R.; Reach, W.; Ginsburg, A.; Kim, S.; Mochizuki, K.; Babler, B.; Block, M.; Bracker, S. B.; Engelbracht, C. W.; For, B. -Q.; Gordon, K.; Hora, J. L.; Leitherer, C.; Meade, M.; Misselt, K.; Sewilo, M.; Vijh, U.; Whitney, B.

    Context. Photoelectric heating is a dominant heating mechanism for many phases of the interstellar medium. We study this mechanism throughout the Large Magellanic Cloud (LMC). Aims. We aim to quantify the importance of the [C II] cooling line and the photoelectric heating process of various

  13. Infrared polarimetry and photometry of BL Lac objects. 2

    Impey, C D [Hawaii Univ., Honolulu (USA). Inst. for Astronomy; Brand, P W.J.L. [Edinburgh Univ. (UK). Dept. of Astronomy; Wolstencroft, R D [Royal Observatory, Edinburgh (UK); Williams, P M [United Kingdom Infrared Telescope Unit, Hilo, Hawaii (USA)

    1984-07-15

    Photometry and polarimetry in the JHK wavebands have now been obtained for 25 BL Lac objects. Several new objects have been monitored for periods of up to five days, and accumulated data is sufficient for a statistical analysis of polarization properties. The selection effects operating on this sample are examined first. A power-law spectrum is consistent with the spectra of all but three objects. A number of important new results are reported.

  14. Luminosities and temperatures of M dwarf stars from infrared photometry

    Veeder, G. J.

    1974-01-01

    Bolometric magnitudes for a large number of M type dwarf stars, obtained by broadband infrared photometry at 1.65, 2.2, and 3.5 microns, are reviewed. The data obtained indicate that one parameter is sufficient to describe the blanketing in all of the UBVRI bands for all types of M dwarfs. In general, late M dwarfs seem to have lower effective temperatures than are predicted by theoretical models.

  15. Infrared polarimetry and photometry of BL Lac objects

    Impey, C.D.; Williams, P.M.

    1984-01-01

    Photometry and polarimetry in the JHK wavebands have now been obtained for 25 BL Lac objects. Several new objects have been monitored for periods of up to five days, and accumulated data is sufficient for a statistical analysis of polarization properties. The selection effects operating on this sample are examined first. A power-law spectrum is consistent with the spectra of all but three objects. A number of important new results are reported. (author)

  16. CCD photometry of Cepheid sequences in four nearby galaxies

    Metcalfe, N.; Shanks, T.

    1991-01-01

    We present Isaac Newton Telescope B and V CCD observations of deep photometric sequences in the vicinity of Cepheid variable stars in three nearby galaxies - M31, M33 and NGC 2403. We have also checked the photometry of the brightest stars in M81 and its dwarf companion, Holmberg IX. We use our data, combined with other recent results, to re-analyse the Cepheid distances to these galaxies. (author)

  17. CCD Photometry of W UMa Type Binary TY UMa

    Young Woon Kang

    2001-06-01

    Full Text Available We present VRI CCD photometry of W UMa type binary TY UMa. The light curves show that the secondary minimum is deeper than theprimary minimum and the maximum I (0.p25 is 0.m023 brighter than the maximum II (0.p75. The V light curve has beenanalyzed and the photometric solutions have been determined by the method of Wilson & Devinney differential correction. Weadopted the spot model to explain the asymetric light curve.

  18. Favorable ultraviolet photoelectric effects in TbMnO3/Nb-SrTiO3 heterostructures

    Jin, Kexin; Zhai, Y. X.; Li, Hui; Tian, Y. F.; Luo, B. C.; Wu, Tao

    2014-01-01

    The rectifying properties and ultraviolet photoelectric effects in TbMnO3/Nb-doped SrTiO3 heterostructures have been investigated. The ideality factors and the diffusion voltages obtained from the current-voltage curves nonlinearly decrease

  19. Size-controllable synthesis of hierarchical copper carbodiimide microcrystals and their pronounced photoelectric response under visible light

    Liu, Qihui [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Liu, Yufeng, E-mail: yfliu@mail.sitp.ac.cn [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Dai, Guozhang [Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Tian, Li [College of Electrical and Information Engineering, Hunan Institute of Engineering, Xiangtan 411101 (China); Xu, Jiayue; Zhao, Guoying; Zhang, Na; Fang, Yongzheng [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)

    2015-12-01

    Graphical abstract: - Highlights: • A controllably aqueous method was presented to synthesize two types of CuNCN microcrystals (MCs) at room temperature. • The size and nanostructure can be tuned via controlling the ratio of [NH{sub 3}]/[Cu{sup +}]. • Moreover, prounounced photoelectric response of the as-prepared CuNCN was observed for the first time under the irradiation of visible light at room temperature. • The aqueous synthetic route can provide an inspiration to acquire the other metal carbodiimides nano/microcrystals without the aid of reducing agents. - Abstract: Similar to cupric oxides and sulfides, the nitrogen-containing analogue copper carbodiimide (CuNCN) is considered as a potentially promising photoelectric material. However, there is lack of fundamental investigations on controllable synthesis and photoelectric properties of CuNCN nano/microcrystals. Herein, a facile method was developed to synthesize high-quality CuNCN semiconductor microcrystals with different sizes and hierarchical nanostructures at room temperature. This reaction was carried out in aqueous solutions, avoiding the involvement of non-aqueous solutions and high temperature solid phase reaction during the synthesis of CuNCN microcrystals. Photoelectric response of as-prepared CuNCN microcrystals was first observed under the irradiation of visible light at room temperature. The aqueous synthetic route can also provide an inspiration to acquire other metal carbodiimides nano/microcrystals.

  20. The vectorial photoelectric effect under solar irradiance and its application to sun sensing

    Hechenblaikner, Gerald; Ziegler, Tobias

    2014-01-01

    Sun sensors are an integral part of the attitude and orbit control system onboard almost any spacecraft. While the majority of standard analogue sun sensors is based on photo-detectors which produce photo-currents proportional to the cosine of the incidence angle (cosine detectors), we propose an alternative scheme where the vectorial photoelectric effect is exploited to achieve a higher sensitivity of the sensed photo-current to the incidence angle. The vectorial photo-effect is investigated in detail for metal cathode detectors in a space environment. Besides long operational lifetimes without significant degradation, metal cathode detectors are insensitive to earth albedo, which may significantly reduce the errors affecting attitude measurements in low earth orbits. Sensitivity curves are calculated and trade-offs performed with the aim of optimizing the sensitivity whilst also providing currents sufficient for detection. Simple applications and detector configurations are also discussed and compared to the existing designs. (paper)

  1. Validation of cross sections for Monte Carlo simulation of the photoelectric effect

    Han, Min Cheol; Pia, Maria Grazia; Basaglia, Tullio; Batic, Matej; Hoff, Gabriela; Kim, Chan Hyeong; Saracco, Paolo

    2016-01-01

    Several total and partial photoionization cross section calculations, based on both theoretical and empirical approaches, are quantitatively evaluated with statistical analyses using a large collection of experimental data retrieved from the literature to identify the state of the art for modeling the photoelectric effect in Monte Carlo particle transport. Some of the examined cross section models are available in general purpose Monte Carlo systems, while others have been implemented and subjected to validation tests for the first time to estimate whether they could improve the accuracy of particle transport codes. The validation process identifies Scofield's 1973 non-relativistic calculations, tabulated in the Evaluated Photon Data Library(EPDL), as the one best reproducing experimental measurements of total cross sections. Specialized total cross section models, some of which derive from more recent calculations, do not provide significant improvements. Scofield's non-relativistic calculations are not surp...

  2. Deconvolving the temporal response of photoelectric x-ray detectors for the diagnosis of pulsed radiations

    Zou, Shiyang; Song, Peng; Pei, Wenbing; Guo, Liang

    2013-01-01

    Based on the conjugate gradient method, a simple algorithm is presented for deconvolving the temporal response of photoelectric x-ray detectors (XRDs) to reconstruct the resolved time-dependent x-ray fluxes. With this algorithm, we have studied the impact of temporal response of XRD on the radiation diagnosis of hohlraum heated by a short intense laser pulse. It is found that the limiting temporal response of XRD not only postpones the rising edge and peak position of x-ray pulses but also smoothes the possible fluctuations of radiation fluxes. Without a proper consideration of the temporal response of XRD, the measured radiation flux can be largely misinterpreted for radiation pulses of a hohlraum heated by short or shaped laser pulses

  3. Sliding mode control of photoelectric tracking platform based on the inverse system method

    Yao Zong Chen

    2016-01-01

    Full Text Available In order to improve the photoelectric tracking platform tracking performance, an integral sliding mode control strategy based on inverse system decoupling method is proposed. The electromechanical dynamic model is established based on multi-body system theory and Newton-Euler method. The coupled multi-input multi-output (MIMO nonlinear system is transformed into two pseudo-linear single-input single-output (SISO subsystems based on the inverse system method. An integral sliding mode control scheme is designed for the decoupled pseudo-linear system. In order to eliminate system chattering phenomenon caused by traditional sign function in sliding-mode controller, the sign function is replaced by the Sigmoid function. Simulation results show that the proposed decoupling method and the control strategy can restrain the influences of internal coupling and disturbance effectively, and has better robustness and higher tracking accuracy.

  4. Photoelectrical Properties and Energetical Structure of Thin Films of Indandione Derivatives

    Maira INDRIKOVA

    2011-07-01

    Full Text Available A sandwich type structure of two dimetilaminobenziliden-1,3-indandione (DMABI derivatives placed between metal electrodes was made to investigate the photoelectrical properties of these derivatives. DMABI is an organic isolator with a wide energy gap and high quantum efficiency of the photogeneration, DMABI derivatives have received also considerable attention because of its large dipole moment and optical nonlinearities. Besides, since it is a photosensitive material, its use in solar systems is very promising. The energy gap of each material and combined system was observed from the spectral dependence of the quantum efficiency of the photoconductivity and results are compared with results of oxidation and reduction potential of the materials. The values showed a good correlation between experimental data of the photoconductivity and voltamperometry and calculated data of the HOMO and LUMO levels of the molecules.http://dx.doi.org/10.5755/j01.ms.17.2.480

  5. Photoelectrical stimulation of neuronal cells by an organic semiconductor-electrolyte Interface

    Abdullaeva, Oliya S.; Schulz, Matthias; Balzer, Frank

    2016-01-01

    As a step toward the realization of neuroprosthetics for vision restoration, we follow an electrophysiological patch-clamp approach to study the fundamental photoelectrical stimulation mechanism of neuronal model cells by an organic semiconductor–electrolyte interface. Our photoactive layer...... consisting of an anilino-squaraine donor blended with a fullerene acceptor is supporting the growth of the neuronal model cell line (N2A cells) without an adhesion layer on it and is not impairing cell viability. The transient photocurrent signal upon illumination from the semiconductor–electrolyte layer....... Furthermore, we characterize the morphology of the semiconductor–electrolyte interface by atomic force microscopy and study the stability of the interface in dark and under illuminated conditions....

  6. CALiPER Report 22.1: Photoelectric Performance of LED MR16 Lamps

    Royer, Michael P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Poplawski, Michael E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Brown, Charles C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Merzouk, Massine B. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-09-01

    This report is a follow-up to CALiPER Application Summary Report 22, which investigated the photometric performance of LED MR16 lamps. The initial report found that many of the LED MR16 lamps did not perform as required by ENERGY STAR based on their equivalency claims, although they generally did provide substantial efficacy advantages compared to halogen MR16 lamps. All testing was completed using laboratory power supplies, with all but one product tested at 12 V AC. In contrast, this report examined the photoelectric performance of the same set of lamps, using commercially available transformers and dimmers as well as laboratory power supplies providing both AC and DC power.

  7. Synthesis of GeSe2 Nanobelts Using Thermal Evaporation and Their Photoelectrical Properties

    Lijie Zhang

    2014-01-01

    Full Text Available GeSe2 nanobelts were synthesized via a simple thermal-evaporation process by using gold particles as catalyst and GeSe2 flakes as starting materials. The morphology, crystal structure, and composition were characterized with scanning electron microscopy (SEM, high-resolution transmission electron microscopy (TEM, X-ray diffraction spectroscopy (XRD, X-ray photoelectron spectroscopy (XPS, and energy-dispersive X-ray spectroscopy (EDS. SEM micrographs show that most of GeSe2 nanobelts have distinct segmented structures (wide belt, zigzag belt, and narrow belt. A possible mechanism was proposed for the growth of segmented nanobelts. It is possible that the growth of the segmented nanobelts is dominated by both vapor-liquid-solid and vapor-solid mechanisms. Devices made of single GeSe2 nanobelt have been fabricated and their photoelectrical property has been investigated. Results indicate that these nanobelt devices are potential building blocks for optoelectronic applications.

  8. Theory of the photoelectric effect assisted by an elliptically polarized laser field

    Li Shumin; Jentschura, Ulrich D

    2009-01-01

    The laser-assisted photoelectric effect in atomic hydrogen is investigated for linear, circular and general elliptic polarizations. The perturbative dressed state of the atom in an elliptically polarized nonresonant laser field is derived in the velocity gauge. The continuum state of the ejected electron is described by a Coulomb-Volkov wavefunction. Numerical results show that the ionization cross section by a vacuum ultraviolet photon is enhanced at high laser field intensities and low frequencies. At small and extremely large scattering angles (measured with respect to the wave vector of the incoming vacuum ultraviolet photon), the process for emitting a laser photon is predominant, while at medium angles, the result favours the process without a laser photon exchange. The dependence of the results on the laser polarization and on various geometries is studied, and an interesting pattern is found for the dependence on the frequency of the dressing laser; an intuitive explanation is offered.

  9. Electromagnetic Spectrum Analysis and Its Influence on the Photoelectric Conversion Efficiency of Solar Cells.

    Hu, Kexiang; Ding, Enjie; Wangyang, Peihua; Wang, Qingkang

    2016-06-01

    The electromagnetic spectrum and the photoelectric conversion efficiency of the silicon hexagonal nanoconical hole (SiHNH) arrays based solar cells is systematically analyzed according to Rigorous Coupled Wave Analysis (RCWA) and Modal Transmission Line (MTL) theory. An ultimate efficiency of the optimized SiHNH arrays based solar cell is up to 31.92% in consideration of the absorption spectrum, 4.52% higher than that of silicon hexagonal nanoconical frustum (SiHNF) arrays. The absorption enhancement of the SiHNH arrays is due to its lower reflectance and more supported guided-mode resonances, and the enhanced ultimate efficiency is insensitive to bottom diameter (D(bot)) of nanoconical hole and the incident angle. The result provides an additional guideline for the nanostructure surface texturing fabrication design for photovoltaic applications.

  10. Electrical, optical and photoelectric properties of cadmium sulfide monocrystals doped by indium and irradiated by electrons

    Davidyuk, G E; Manzhara, V S

    2002-01-01

    One studied effect of irradiation by E = 1.2 MeV energy and PHI = 2 x 10 sup 1 sup 7 cm sup - sup 2 dose fast electrons on electrical, optical and photoelectrical CdS single-crystals doped by In. On the basis of analysis of the experimental results one makes conclusions about decomposition and, in this case, indium atoms occurring in cation sublattice nodes are knocked out by cadmium atoms. In CdS:In irradiated specimens one detected new centres of slow recombination with occurrence of maximums of photoconductivity optical suppression within lambda sub M sub sub 1 = 0.75 mu m and lambda sub M sub sub 2 = 1.03 mu m range. It is assumed that complexes containing cadmium vacancies and indium atoms are responsible for recombination new centres

  11. Experimental investigation on photoelectric properties of ZAO thin film deposited on flexible substrate by magnetron sputtering

    Hao, Ming; Liu, Kun; Liu, Xinghua; Wang, Dongyang; Ba, Dechun; Xie, Yuanhua; Du, Guangyu; Ba, Yaoshuai

    2016-12-01

    Transparent conductive ZAO (Zinc Aluminum Oxide) films on flexible substrates have a great potential for low-cost mass-production solar cells. ZAO thin films were achieved on flexible PET (polyethylene terephthalate) substrates by RF magnetron sputtering technology. The surface morphology and element content, the transmittance and the sheet resistance of the films were measured to determine the optical process parameters. The results show that the ZAO thin film shows the best parameters in terms of photoelectric performance including sputtering power, working pressure, sputtering time, substrate temperature (100 W, 1.5 Pa, 60 min, 125 °C). The sheet resistance of 510 Ω and transmittance in visible region of 92% were obtained after characterization. Surface morphology was uniform and compact with a good crystal grain.

  12. Study on photoelectric parameter measurement method of high capacitance solar cell

    Zhang, Junchao; Xiong, Limin; Meng, Haifeng; He, Yingwei; Cai, Chuan; Zhang, Bifeng; Li, Xiaohui; Wang, Changshi

    2018-01-01

    The high efficiency solar cells usually have high capacitance characteristic, so the measurement of their photoelectric performance usually requires long pulse width and long sweep time. The effects of irradiance non-uniformity, probe shielding and spectral mismatch on the IV curve measurement are analyzed experimentally. A compensation method for irradiance loss caused by probe shielding is proposed, and the accurate measurement of the irradiance intensity in the IV curve measurement process of solar cell is realized. Based on the characteristics that the open circuit voltage of solar cell is sensitive to the junction temperature, an accurate measurement method of the temperature of solar cell under continuous irradiation condition is proposed. Finally, a measurement method with the characteristic of high accuracy and wide application range for high capacitance solar cell is presented.

  13. Photoelectric effect experiment for understanding the concept of quantization of radiation energy

    Yeimy Gerardine Berrios Saavedra

    2016-09-01

    Full Text Available This study forms part of research on the teaching of physics. The question that directed it was: How a proposed classroom, based on the photoelectric effect experiment helps pres-service teachers of physics of the Universidad Pedagógica Nacional to expand their understanding of the concept of quantization energy of radiation? The construction of the theoretical framework developed on the one hand, with scientific ideas about the quantization of energy, and moreover, with the educational proposals of teaching for understanding. This pedagogical approach was guided by the investigative gaze of the study methodology based on design, taking as main element the use of learning tools such as the task to Predict, Experiment and Explain (PEE. It was found that these tasks fomented the initial understandings of students about the concept, while they enriched and transformed progressively their models and scientific ideas, promoting aspects of scientific work in developing curiosity, imagination and motivation.

  14. UBV photometry of dwarf novae in the brightness minimum

    Voloshina, I.B.; Lyutyj, V.M.

    1983-01-01

    Photoelectric one-night observations of the dwarf novae SS Cyg at minimum light evidence for the existence of eclipses in this system at the moments of conjuctions. The orbital inclination of the system is estimated to be i approximately 70 deg C. The components of this system are low-massive (white and red dwarf stars) and low-luminous objects. As the optical luminosity of the dwarf novae at the minimum light is dependent on the accretion disk and hot spot at its periphery, where the substance jet run out from a nondegenerated component falls, eclipses should be associated with the disk and hot spot. The white dwarf star contributes greatly to the luminosity at the minimum light, but its eclipses are possible only at i approximately 90 deg

  15. Laser-assisted preparation and photoelectric properties of grating-structured Pt/FTO thin films

    Ren, Nai-fei, E-mail: rnf_ujs@126.com [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); Huang, Li-jing, E-mail: lij_huang@126.com [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Li, Bao-jia [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Zhou, Ming [Jiangsu Provincial Key Laboratory of Center for Photon Manufacturing Science and Technology, Jiangsu University, Zhenjiang 212013 (China); The State Key Laboratory of Tribology, Tsinghua University, Beijing 100084 (China)

    2014-09-30

    Highlights: • Pt layers were deposited by DC magnetron sputtering on commercial FTO glasses. • Pt/FTO films were irradiated by laser for inducing gratings and annealing. • An ideal grating-structured Pt/FTO film was obtained using a fluence of 1.05 J/cm{sup 2}. • The grating-structured Pt/FTO film exhibited excellent photoelectric properties. • Laser-assisted treatment is effective for improving performance of FTO-based films. - Abstract: In order to improve the transparency and conductivity of commercial fluorine-doped tin oxide (FTO) glass, platinum (Pt) layers were deposited on the FTO film by direct current (DC) magnetron sputtering, followed by being irradiating with a 532 nm nanosecond pulsed laser for the dual purpose of inducing grating structures and annealing. Introducing a Pt layer decreased the average transmittance (400–800 nm) and the sheet resistance of the initial FTO film from 80.2% and 8.4 Ω/sq to 68.6% and 7.9 Ω/sq, respectively. The ideal grating-structured Pt/FTO film was obtained by laser irradiation with a fluence of 1.05 J/cm{sup 2}, and X-ray diffraction (XRD) analysis confirmed that this film underwent optimal annealing. As a result, it exhibited an average transmittance (400–800 nm) of 84.1% and a sheet resistance of 6.8 Ω/sq. These results indicated that laser-assisted treatment combined with introduction of metal layer can effectively improve photoelectric properties of FTO single-layer films.

  16. Infrared photometry of upper main sequence stars in M39

    Manteiga, M.; Martinez-Roger, C.; Morales, C.; Sabau, L.

    1991-01-01

    Infrared photometry of 19 Main sequence stars in the open cluster M39 is presented. Infrared-infrared and optical-infrared colour-colour and colour-magnitude diagrams are presented and compared with mean intrinsic colours for Population I stars. An interstellar reddening of E(B - V) = 0.01 is obtained by analysis of the colour-colour diagrams. Comparison with a set of theoretical isochrones leads to an age estimate for the cluster between 2.4 and 4.8 x 10 8 years

  17. Infrared polarimetry and photometry of BL Lac objects. 3

    Holmes, P A; Brand, P W.J.L. [Edinburgh Univ. (UK). Dept. of Astronomy; Impey, C D [Hawaii Univ., Honolulu (USA). Inst. for Astronomy; Williams, P M [UKIRT, Hilo, HI (USA)

    1984-10-15

    The data presented here is part of a continuing monitoring programme of BL lac objects with J, H and K photometry and polarimetry. A total of 30 BL Lac objects have now been observed photometrically. Infrared polarimetry has also been obtained for 24 of these objects. The sample is sufficiently large to examine statistically, and several important correlations have emerged. Internight variations and wavelength dependence of polarization indicate that BL Lac objects, as a class, may be understood in terms of a relatively simple two-component model.

  18. uvby photometry in McCormick proper motion fields

    Degewij, J.

    1982-01-01

    The Danish 50 cm telescope at the European Southern Observatory was used to obtain high-precision uvby photometry for 50 F2 to G2 stars, with V values in the 9.4-12.3 mag range, which were selected in the southern galactic polar regions of the McCormick proper motion fields and measured on six different nights. The brighter stars are found to systematically exhibit smaller m(1) indices, of about 0.02 mag, upon comparison with the earlier data of Blaauw et al (1976). Single measurements are given for 98 stars in eight McCormick fields at intermediate southern galactic latitudes.

  19. Infrared photometry of upper main sequence stars in M39

    Manteiga, M.; Martinez-Roger, C. (Instituto de Astrofisica de Canarias, Tenerife, (ES)); Morales, C.; Sabau, L. (Instituto de Tecnica Aeroespacial, Madrid, (ES))

    1991-03-01

    Infrared photometry of 19 Main sequence stars in the open cluster M39 is presented. Infrared-infrared and optical-infrared colour-colour and colour-magnitude diagrams are presented and compared with mean intrinsic colours for Population I stars. An interstellar reddening of E(B - V) = 0.01 is obtained by analysis of the colour-colour diagrams. Comparison with a set of theoretical isochrones leads to an age estimate for the cluster between 2.4 and 4.8 x 10{sup 8} years.

  20. OV Bootis: Forty Nights of World-Wide Photometry (Abstract)

    Patterson, J.; de Miguel, E.; Barret, D.; Brincat, S.; Boardman, J., Jr.; Buczynski, D.; Campbell, T.; Cejudo, D.; Cook, L.; Cook, M. J.; Collins, D.; Cooney, W.; Dubois, F.; Dvorak, S.; Halpern, J. P.; Kroes, A. J.; Lemay, D.; Licchelli, D.; Mankel, D.; Marshall, M.; Novak, R.; Oksanen, A.; Roberts, G.; Seargeant, J.; Sears, H.; Silcox, A.; Slauson, D.; Stone, G.; Thorstensen, J. R.; Ulowetz, J.; Vanmunster, T.; Wallgren, J.; Wood, M.

    2017-12-01

    (Abstract only) Among the 1000 known cataclysmic variables, only one appears to belong to the "Galactic halo"-the Population II stars. We report round-the-world photometry of this star (OV Boo) during March-April 2017, when it staged its first certified dwarf-nova outburst. The star is remarkable for its short binary period (66 minutes), high proper motion, metal-poor composition, substellar secondary, sharp white-dwarf eclipses, and nonradial pulsations. Something for everybody - and it even had the good manners to erupt in northern springtime, when it transits near local midnight. Move over, SS Cyg and WZ Sge; there's a new celebrity in town!

  1. The Photometry Pipeline of the Watcher Robotic Telescope

    A. Ferrero

    2010-01-01

    Full Text Available The Watcher robotic telescope was developed primarily to perform rapid optical follow-up observations of Gamma-Ray Bursts (GRBs. Secondary scientific goals include blazar monitoring and variable star studies. An automated photometry pipeline to rapidly analyse data from Watcher has been implemented. Details of the procedures to get image zero-point, source instrumental measurement, and limiting magnitude are presented. Sources of uncertainty are assessed and the performance of the pipeline is tested by comparison with a number of catalogue sources.

  2. Cepheid distance scale: a new application for infrared photometry

    McGonegal, R.; McLaren, R.A.; McAlary, C.W.; Madore, B.F.

    1982-01-01

    It is shown that near-infrared photometry of Cepheid variables provides a powerful and practical means of calibrating the distance scale to nearby galaxies. Compared with similar work in the blue, random-phase observations in the near-infrared produce a factor of 2.5 decrease in the apparent width of the period-luminosity relation. This we attribute to a substantially decreased effect of differential reddening at long wavelengths, to the low sensitivity of the infrared flux to metallicity variations, and furthermore to the fact that the cyclical luminosity variations are also greatly reduced in the infrared

  3. Improving the Photometry of the Pi of the Sky System

    A. F. Żarnecki

    2011-01-01

    Full Text Available The “Pi of the Sky” robotic telescope was designed to monitor a significant fraction of the sky with good time resolution and range. The main goal of the “Pi of the Sky” detector is to look for short timescale optical transients arising from various astrophysical phenomena, mainly for the optical counterparts of Gamma Ray Bursts (GRB. The system design, the observation methodology and the algorithms that have been developed make this detector a sophisticated instrument for looking for novae and supernovae stars and for monitoring blasars and AGNs activity. The final detector will consist of two sets of 12 cameras, one camera covering a field of view of 20◦ ×20◦. For data taken with the prototype detector at the Las Campanas Observatory, Chile, photometry uncertainty of 0.018–0.024 magnitudo for stars 7–10m was obtained. With a new calibration algorithm taking into account the spectral type of reference stars, the stability of the photometry algorithm can be significantly improved. Preliminary results from the BGInd variable are presented, showing that uncertainty of the order of 0.013 can be obtained.

  4. BVI CCD photometry of the globular cluster M4

    Alcaino, G.; Liller, W.; Alvarado, F.

    1988-01-01

    CCD BV1 main-sequence (MS) photometry of M4, the globular cluster closest to the sun, is presented. The photometry is matched to the BVI isochrones of VandenBerg and Bell (1985). The MS turnoffs are found to be at V = 16.90 + or - 0.05, B-V = 0.81 + or - 0.02, V-I = 0.96 + or - 0.02, and B - I = 1.77 + or - 0.02. The magnitude difference between the MS turnoff and the horizontal branch is Delta M(V) = 3.52 + or - 0.1 for all three color indices. Using Y = 0.2, (Fe/H) = - 1.27, and alpha = 1.65, with a distance modulus of (m-M)V = 12.7 and E(B-V) = 0.41, a consistent age for M4 is deduced in all three color indices of 17 + or - 1.5 Gyr. 34 references

  5. Stellar CCD Photometry: New Approach, Principles and Application

    El-Bassuny Alawy, A.

    A new approach is proposed and developed to handle pre-processed CCD frames in order to identify stellar images and derive their relevant parameters. It relies on: 1) Identifying stellar images and assigning approximate positions of their centres using an artificial intelligence technique, (Knowledge Based System), 2) Accurate determination of the centre co-ordinates applying an elementary statistical concept and 3) Estimating the image peak intensity as a stellar magnitude measure employing simple numerical analysis approach. The method has been coded for personal computer users. A CCD frame of the star cluster M67 was adopted as a test case. The results obtained are discussed in comparison with the DAOPHOTII ones and the corresponding published data. Exact coincidence has been found between both results except in very few cases. These exceptions have been discussed in the light of the basis of both methods and the cluster plates. It has been realised that the method suggested represents a very simple, extremely fast, high precision method of stellar CCD photometry. Moreover, it is more capable than DAOPHOTII of handling blended and distorted stellar images. These characteristics show the usefulness of the present method in some astronomical applications, such as auto-focusing and auto-guiding, beside the main purpose, viz. stellar photometry.

  6. Progress in photometry. Sokko ni okeru saikinno shinpo

    Krochmann, J

    1991-07-01

    A recent progress in photometry was summarized. As to photometric error, photometric head, luminous intensity, luminous flux, and lighting system, a present situation was introduced. Was described the error in photometry using a silicon photodiode, which became in a level of 0.1% by the self-calibration. Also were illustrated the photometric heads for evaluating spatial luminous intensities, the detector for ratio temperature measurement needed for calibration of a normal standard light source, the filter-type monochromator for measuring a difference of spectral response, and the solar battery for reference which can correct the photometer used for the long period in the field. A measurement of high-speed photocurrent was shown, in which the resolving power of 10{sup {minus}14}ampere (10{sup {minus}6}lux) can be achieved. A goniophotometer for luminous flux measurement was also introduced. Furthermore, the stimulation direct-reading colorimeter, the reflectance and transmission measuring apparatus, the illumination meter with a remote control transmitter, the diffuse reflectance measuring apparatus, and the daylight factor measuring apparatus were illustrated. 14 refs., 11 figs.

  7. STELLAR POPULATIONS IN MEDIUM REDSHIFT CLUSTERS .2. OPTICAL-INFRARED PHOTOMETRY AND SPECTRA

    PICKLES, AJ; VANDERKRUIT, PC

    1991-01-01

    We present optical and infrared photometry (BV RI, J H K) and spectra of galaxies in 6 medium redshift clusters covering the redshift range 0.19 less-than-or-equal-to z less-than-or-equal-to 0.4. The array photometry is used to note the radial distribution of the cluster galaxies with optical and

  8. The fundamental parameter approach of quantitative XRFA- investigation of photoelectric absorption coefficients

    Shaltout, A.

    2003-06-01

    The present work describes some actual problems of quantitative x-ray fluorescence analysis by means of the fundamental parameter approach. To perform this task, some of the main parameters are discussed in detail. These parameters are photoelectric cross sections, coherent and incoherent scattering cross sections, mass absorption cross sections and the variation of the x-ray tube voltage. Photoelectric cross sections, coherent and incoherent scattering cross sections and mass absorption cross sections in the energy range from 1 to 300 keV for the elements from Z=1 to 94 considering ten different data bases are studied. These are data bases given by Hubbell, McMaster, Mucall, Scofield, Xcom, Elam, Sasaki, Henke, Cullen and Chantler's data bases. These data bases have been developed also for an application in fundamental parameter programs for quantitative x-ray analysis (Energy Dispersive X-Ray Fluorescence Analysis (EDXRFA), Electron Probe Microanalysis (EPMA), X-Ray Photoelectron Spectroscopy (XPS) and Total Electron Yield (TEY)). In addition a comparison is performed between different data bases. In McMaster's data base, the missing elements (Z=84, 85, 87, 88, 89, 91, and 93) are added by using photoelectric cross sections of Scofield's data base, coherent as well as incoherent scattering cross sections of Elam's data base and the absorption edges of Bearden. Also, the N-fit coefficients of the elements from Z=61 to 69 are wrong in McMaster data base, therefore, linear least squares fits are used to recalculate the N-fit coefficients of these elements. Additionally, in the McMaster tables the positions of the M- and N-edges of all elements with the exception of the M1- and N1- edges are not defined as well as the jump ratio of the edges. In the present work, the M- and N-edges and the related jump ratios are calculated. To include the missing N-edges, Bearden's values of energy edges are used. In Scofield's data base, modifications include check and correction

  9. Photoelectric characteristics of CH3NH3PbI3/p-Si heterojunction

    Yamei, Wu; Ruixia, Yang; Hanmin, Tian; Shuai, Chen

    2016-05-01

    Organic-inorganic hybrid perovskite CH3NH3PbI3 film is prepared on p-type silicon substrate using the one-step solution method to form a CH3NH3PbI3/p-Si heterojunction. The film morphology and structure are characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The photoelectric properties of the CH3NH3PbI3/p-Si heterojunction are studied by testing the current-voltage (I-V) with and without illumination and capacitance-voltage (C-V) characteristics. It turns out from the I-V curve without illumination that the CH3NH3PbI3/p-Si heterojunction has a rectifier feature with the rectification ratio over 70 at the bias of ±5 V. Also, there appears a photoelectric conversion phenomenon on this heterojunction with a short circuit current (Isc) of 0.16 μA and an open circuit voltage (Voc) of about 10 mV The high frequency C-V characteristic of the Ag/CH3NH3PbI3/p-Si heterojunction turns out to be similar to that of the metal-insulator-semiconductor (MIS) structure, and a parallel translation of the C-V curve along the forward voltage axis is found. This parallel translation means the existence of defects at the CH3NH3PbI3/p-Si interface and positive fixed charges in the CH3NH3PbI3 layer. The defects at the interface of the CH3NH3PbI3/p-Si heterojunction result in the dramatic decline of the Voc. Besides, the C-V test of CH3NH3PbI3 film shows a non-linear dielectric property and the dielectric value is about 4.64 as calculated. Project supported by the Hebei Province Natural Science Foundation of China (No. F2014202184) and the Tianjin Natural Science Foundation of China (No. 15JCZDJC37800).

  10. Photoelectric emission from negative-electron-affinity diamond (111) surfaces: Exciton breakup versus conduction-band emission

    Bandis, C.; Pate, B.B.

    1995-01-01

    We have recently reported that bound electron-hole pairs (Mott-Wannier excitons) are the dominant source of photoelectron emission from specially prepared [''as-polished'' C(111)-(1x1):H] negative-electron-affinity diamond surfaces for near-band-gap excitation up to 0.5 eV above threshold [C. Bandis and B. B. Pate, Phys. Rev. Lett. 74, 777 (1995)]. It was found that photoexcited excitons transport to the surface, break up, and emit their electron. In this paper, we extend the study of exciton-derived emission to include partial yield (constant final-state) analysis as well as angular distribution measurements of the photoelectric emission. In addition, we find that exciton-derived emission does not always dominate. Photoelectric emission properties of the in situ ''rehydrogenated'' (111)-(1x1):H diamond surface are characteristically different than emission observed from the as-polished (111)-(1x1):H surface. The rehydrogenated surface has additional downward band bending as compared to the as-polished surface. In confirmation of the assignment of photoelectric yield to exciton breakup emission, we find a significant enhancement of the total electron yield when the downward band bending of the hydrogenated surface is increased. The functional form of the observed total electron yield demonstrates that, in contrast to the as-polished surface, conduction-band electrons are a significant component of the observed photoelectric yield from the in situ hydrogenated (111)-(1x1):H surface. Furthermore, electron emission characteristics of the rehydrogenated surface confirms our assignment of a Fan phonon-cascade mechanism for thermalization of excitons

  11. Measurement of L-shell photoelectric cross sections in high Z elements at 37 and 74 keV

    Allawadhi, K L; Ghumman, B S; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1977-05-01

    L-shell photoelectric cross section measurements have been made at 36.818 and 74.409 keV for four elements in the range 81<=Z<=92. The measurements at 74.409 keV are found to agree with theory, within experimental uncertainties, but the experimental values at 36.818 keV are found to be higher than the theoretical predictions. The possible reasons for the observed discrepancy are discussed.

  12. KIC 8462852: Maria Mitchell Observatory Photographic Photometry 1930 to 1985

    Castelaz, Michael; Barker, Thurburn

    2018-01-01

    KIC 8462852 is an F3V star which decreased 20% in visual brightness twice from 5 to 20 days (Boyajian et al., 2016, MNRAS, 457, 3988) in 2011 and again in 2013. New observations show decreases of a few percent in May 2017 (Waagen 2017, AAVSO Alert Notice, 579), and reanalysis of Kepler data shows a variation of 928.25 days and 22 dimming events (Kiefer et al. 2017, accepted). Photometry from the All-Sky Automated Survey for Supernovae and the All-Sky Automated Survey (ASAS) indicate two brightening episodes and a steady decrease in magnitude of 6.3 +/- 1.4 mmag/yr (Simon et al 2017, accepted). Photometric studies from photographic plate collections include a light curve from 1338 Harvard College Observatory plates over the period 1890 to 1989 (Schaefer 2016, ApJ, 822, L34) that indicates KIC 8462852 is dimming 0.164 +/- 0.013 magnitudes per century. Hippke et al. (2016, ApJ, 825, 73) present B and V light curves from photometry from the Sonneberg Observatory photographic plate collection (Brauer and Fuhrmann 1992, Die Sterne, 68, 19) covering the period from 1934 to 1995. The light curve suggests less than 3% or 0.03 magnitude per century decrease in brightness, consistent with the ASAS light curve and Kepler data.Another consistent set of astronomical photographic plates with KIC 8462852 are in the Maria Mitchell Observatory (MMO) collection (Strelnitski 2009 in ASP Conference Series Vol. 410 p. 96). This collection is located in the Astronomical Photographic Data Archive at the Pisgah Astronomical Research Institute. We extracted the photographic magnitudes of KIC 8462852 from 743 plates from 1930 to 1988. We chose 8 nearby comparison stars within one spectral subclass and within 0.05 magnitudes of KIC 8462852, and not identified as variables. The photometry is calibrated to the USNO B filter, closest in bandpass to the emulsion wavelength sensitivity. The light curve of KIC 8462852 suggests a trend of about 0.1 +/- 0.07 magnitudes per century decrease, an

  13. Metal/Semiconductor and Transparent Conductor/Semiconductor Heterojunctions in High Efficient Photoelectric Devices: Progress and Features

    M. Melvin David Kumar

    2014-01-01

    Full Text Available Metal/semiconductor and transparent conductive oxide (TCO/semiconductor heterojunctions have emerged as an effective modality in the fabrication of photoelectric devices. This review is following a recent shift toward the engineering of TCO layers and structured Si substrates, incorporating metal nanoparticles for the development of next-generation photoelectric devices. Beneficial progress which helps to increase the efficiency and reduce the cost, has been sequenced based on efficient technologies involved in making novel substrates, TCO layers, and electrodes. The electrical and optical properties of indium tin oxide (ITO and aluminum doped zinc oxide (AZO thin films can be enhanced by structuring the surface of TCO layers. The TCO layers embedded with Ag nanoparticles are used to enhance the plasmonic light trapping effect in order to increase the energy harvesting nature of photoelectric devices. Si nanopillar structures which are fabricated by photolithography-free technique are used to increase light-active surface region. The importance of the structure and area of front electrodes and the effect of temperature at the junction are the value added discussions in this review.

  14. Photoelectric properties of the metamorphic InAs/InGaAs quantum dot structure at room temperature

    Golovynskyi, S. L., E-mail: golovynskyi@isp.kiev.ua [Institute of Semiconductor Physics, National Academy of Sciences, pr. Nauki 45, 03028 Kyiv (Ukraine); Seravalli, L.; Trevisi, G.; Frigeri, P.; Gombia, E. [Institute of Materials for Electronics and Magnetism, CNR-IMEM, Parco delle Scienze 37a, I-43100 Parma (Italy); Dacenko, O. I.; Kondratenko, S. V. [Department of Physics, Taras Shevchenko National University of Kyiv, 64 Volodymyrska St., 01601 Kyiv (Ukraine)

    2015-06-07

    We present the study of optical and photoelectric properties of InAs quantum dots (QDs) grown on a metamorphic In{sub 0.15}Ga{sub 0.85}As buffer layer: such nanostructures show efficient light emission in the telecom window at 1.3 μm (0.95 eV) at room temperature. We prepared a sample with vertical geometry of contacts isolated from the GaAs substrate. The structure is found to be photosensitive in the spectral range above 0.9 eV at room temperature, showing distinctive features in the photovoltage and photocurrent spectra attributed to QDs, InAs wetting layer, and In{sub 0.15}Ga{sub 0.85}As metamorphic buffer, while a drop in the photoelectric signal above 1.36 eV is related to the GaAs layer. No effect of defect centers on the photoelectrical properties is found, although they are observed in the absorption spectrum. We conclude that metamorphic QDs have a low amount of interface-related defects close to the optically active region and charge carriers can be effectively collected into InAs QDs.

  15. Photochemical charges separation and photoelectric properties of flexible solar cells with two types of heterostructures

    Liu, Xiangyang, E-mail: lxy081276@126.com, E-mail: yzgu@henu.edu.cn; Wang, Shun; Zheng, Haiwu; Cheng, Xiuying; Gu, Yuzong, E-mail: lxy081276@126.com, E-mail: yzgu@henu.edu.cn [Institute of Microsystems Physics and School of Physics and Electronics, Henan University, Kaifeng 475004 (China)

    2015-12-14

    Photochemical charges generation, separation, and transport at nanocrystal interfaces are central to energy conversion for solar cells. Here, Zn{sub 2}SnO{sub 4} nanowires/Cu{sub 4}Bi{sub 4}S{sub 9} (ZTO/CBS), ZTO nanowires/CBS-reduced graphene oxide (ZTO/CBS-RGO), and bulk heterojunction (BHJ) solar cells were measured. The signals of steady state and electric field-induced surface photovoltage indicate that RGO with high electron mobility can evidently improve the photovoltaic response. Besides, ZTO/CBS and ZTO/CBS-RGO cells exhibit the excellent performance and the highest efficiencies of 1.2% and 2.8%, respectively. The internal relations of photoelectric properties to some factors, such as film thickness, direct paths, RGO conductive network, energy level matching, etc., were discussed in detail. Qualitative and quantitative analyses further verified the comprehensive effect of RGO and other factors. Importantly, the fine bendable characteristic of BHJ solar cells with excellent efficiency and facile, scalable production gives the as-made flexible solar cells device potential for practical application in future.

  16. Transparent Cu4O3/ZnO heterojunction photoelectric devices

    Kim, Hong-Sik; Yadav, Pankaj; Patel, Malkeshkumar; Kim, Joondong; Pandey, Kavita; Lim, Donggun; Jeong, Chaehwan

    2017-12-01

    The present article reports the development of flexible, self-biased, broadband, high speed and transparent heterojunction photodiode, which is essentially important for the next generation electronic devices. We grow semitransparent p-type Cu4O3 using the reactive sputtering method at room temperature. The structural and optical properties of the Cu4O3 film were investigated by using the X-ray diffraction and UV-visible spectroscopy, respectively. The p-Cu4O3/n-ZnO heterojunction diode under dark condition yields rectification behavior with an extremely low saturation current value of 1.8 × 10-10 A and a zero bias photocurrent under illumination condition. The transparent p-Cu4O3/n-ZnO heterojunction photodetector can be operated without an external bias, due to the light-induced voltage production. The metal oxide heterojunction based on Cu4O3/ZnO would provide a route for the transparent and flexible photoelectric devices, including photodetectors and photovoltaics.

  17. ANALYSIS OF THE ELECTROPHYSICAL AND PHOTOELECTRIC PROPERTIES OF NANOCOMPOSITE POLYMERS BY THE MODIFIED KELVIN PROBE

    K. U. Pantsialeyeu

    2017-01-01

    Full Text Available At present for analysis of the homogeneity of materials properties are becoming widely used various modifications of a scanning Kelvin probe. These methods allow mapping the spatial distribution of the electrostatic potential. Analysis of the electropotential profile is not sufficient to describe any specific physical parameters of the polymer nanocomposites. Therefore, we use an external energy impact, such as light. Purpose of paper is the modification of the Kelvin scanning probe and the conduct of experimental studies of the spatial distribution and response of the electrostatic potential of the actual polymer nanocomposites to the optical probing.Carried out the investigations on experimental Low density polyethylene composites. Carbon nanomaterials and nanoparticles of silicon dioxide or aluminum as fillers are used. As a result, maps of the spatial distribution of the electrostatic potential relative values and the surface photovoltage. Statistical analysis of the electrophysical and photoelectric properties homogeneity, depending on the component composition of the composites carried out. In addition, with reference to matrix polymers, the Kelvin scanning probe, in combination with the optical probing, made it possible to detect a piezoelectric effect. The latter, can used as a basis for the development of new methods for studying the mechanical properties of matrix polymers.

  18. Determination of X-ray photoelectric absorption of Ge and Si avoiding solid-state effects

    Baltazar-Rodrigues, J.; Cusatis, C.

    2001-01-01

    X-ray linear attenuation coefficients of germanium and silicon were measured with precision between 0.1% and 0.3% for six characteristic wavelengths: copper, molybdenum and silver K lines. The linear photoelectric absorption coefficients were determined from the values of the measured attenuation coefficients by subtracting the calculated Compton and thermal diffuse scattering involved. It is shown that in order to compare calculated values of X-ray absorption coefficients based on the isolated atom assumption with experimental results obtained from solid samples it is necessary to take into consideration the solid-state effects. Before the measurements the sample's angular positions were scanned to search for Bragg scattering and the measurements of the transmitted intensities were done far from these angular positions. The measurements were performed in three samples of each element with different thickness and in different angular positions for each sample in order to check the consistency of the measured attenuation coefficients. Several instrumental and experimental details were considered in order to achieve the final asserted precision

  19. Subdivision Error Analysis and Compensation for Photoelectric Angle Encoder in a Telescope Control System

    Yanrui Su

    2015-01-01

    Full Text Available As the position sensor, photoelectric angle encoder affects the accuracy and stability of telescope control system (TCS. A TCS-based subdivision error compensation method for encoder is proposed. Six types of subdivision error sources are extracted through mathematical expressions of subdivision signals first. Then the period length relationships between subdivision signals and subdivision errors are deduced. And the error compensation algorithm only utilizing the shaft position of TCS is put forward, along with two control models; Model I is that the algorithm applies only to the speed loop of TCS and Model II is applied to both speed loop and position loop. Combined with actual project, elevation jittering phenomenon of the telescope is discussed to decide the necessity of DC-type subdivision error compensation. Low-speed elevation performance before and after error compensation is compared to help decide that Model II is preferred. In contrast to original performance, the maximum position error of the elevation with DC subdivision error compensation is reduced by approximately 47.9% from 1.42″ to 0.74″. The elevation gets a huge decrease in jitters. This method can compensate the encoder subdivision errors effectively and improve the stability of TCS.

  20. Protection of High Ceiling Nuclear Facilities Using Photoelectric Sensors and Infrared Fire Detectors

    Wadoud, A.A.; El Eissawi, H.M.; Saleh, A.A.

    2017-01-01

    A variety of different security systems and components are commercially available and widely used. Before implementing a security system, it is important to understand the characteristics and requirements of the facility area to be protected. Technology and manufacturers of security devices are rapidly changing. It is necessary to use optimal security equipment suitable for the surrounding environment of the facility to be protected. Several security sensors can be used to protect the nuclear facilities, such as passive infrared detectors and glass breakage sensors, vibration detectors, and microwave sensors. This work introduces technical specifications, operation and method of installation for these detectors in nuclear facilities. Also a comparative study of different security sensors or equipment is provided. The photoelectric detectors and infrared fire beam smoke detectors are reliable, suitable and advanced security equipment. They can be used in special cases because of their advantages, this includes their long ranges and accuracy in performance. This paper presents a new concept for adapting the use infrared optical fire beam smoke detector as intrusion detection equipment in high ceiling buildings or towering height facilities. This is in addition to their main function, namely fire detection.The paper also provides a study for their types and installation method. Focus is made on the installation and operation method for two advanced security systems, and wireless control circuit for the overall system operation

  1. Multipulse nanosecond laser irradiation of silicon for the investigation of surface morphology and photoelectric properties

    Sardar, Maryam; Chen, Jun; Ullah, Zaka; Jelani, Mohsan; Tabassum, Aasma; Cheng, Ju; Sun, Yuxiang; Lu, Jian

    2017-12-01

    We irradiate the single crystal boron-doped silicon (Si) with different number of laser pulses at constant fluence (7.5 J cm-2) in ambient air using Nd:YAG laser and examine its surface morphology and photoelectric properties in details. The results obtained from optical micrographs reveal the increase in heat affected zone (HAZ) and melted area of laser irradiated Si with increasing number of laser pulses. The SEM micrographs evidence the formation of various surface morphologies like laser induced periodic surface structures, crater, microcracks, clusters, cavities, pores, trapped bubbles, nucleation sites, micro-bumps, redeposited material and micro- and nano-particles on the surface of irradiated Si. The surface profilometry analysis informs that the depth of crater is increased with increase in number of incident laser pulses. The spectroscopic ellipsometry reveals that the multipulse irradiation of Si changes its optical properties (refractive index and extinction coefficient). The current-voltage (I-V) characteristic curves of laser irradiated Si show that although the multipulse laser irradiation produces considerable number of surface defects and damages, the electrical properties of Si are well sustained after the multipulse irradiation. The current findings suggest that the multipulse irradiation can be an effective way to tune the optical properties of Si for the fabrication of wide range of optoelectronic devices.

  2. Photoelectric professional students in common universities cultivate way to explore under the background of professional certification

    Sun, Yan-jun; Wang, Li; Leng, Yan-bing

    2017-08-01

    In view of the engineering education professional certification of specialty construction and the specific requirements of the training system, combining with our school optoelectronic information science and engineering characteristics, analysis of the optoelectronic information science and engineering in our school problems and challenges, to locate the specific professional training objectives. From the service oriented industry demand for talent ability, at the same time, according to the ministry of education professional norms of the development of the photoelectric teaching steering committee, and the professional development and the characteristics of target, to build a set to conform to the goal of cultivating the professional curriculum system. At the same time set up a from fundamental to professional practice teaching system, covers the course experiment, course design, case teaching, comprehensive training, such as graduation design practice. Which implements a whole ability training from the practice of foundation to high-end chain, embodies the training goal emphasize "outstanding practical skills, quality education is distinct culture characteristic. By further speed up the professional construction, professional certification standards to standardize our training process, improved the level of professional training, and improve the comprehensive quality of the graduates and talent of social competitiveness, fostered more professional talents for the country.

  3. CdTe polycrystalline films on Ni foil substrates by screen printing and their photoelectric performance

    Yao, Huizhen; Ma, Jinwen; Mu, Yannan; Su, Shi; Lv, Pin; Zhang, Xiaoling; Zhou, Liying; Li, Xue; Liu, Li; Fu, Wuyou; Yang, Haibin

    2015-01-01

    Highlights: • The sintered CdTe polycrystalline films by a simple screen printing. • The flexible Ni foil was chose as substrates to reduce the weight of the electrode. • The compact CdTe film was obtained at 550 °C sintering temperature. • The photoelectric activity of the CdTe polycrystalline films was excellent. - Abstract: CdTe polycrystalline films were prepared on flexible Ni foil substrates by sequential screen printing and sintering in a nitrogen atmosphere for the first time. The effect of temperature on the quality of the screen-printed film was investigated in our work. The high-quality CdTe films were obtained after sintering at 550 °C for 2 h. The properties of the sintered CdTe films were characterized by scanning electron microscopy, X-ray diffraction pattern and UV–visible spectroscopy. The high-quality CdTe films have the photocurrent was 2.04 mA/cm 2 , which is higher than that of samples prepared at other temperatures. Furthermore, CdCl 2 treatment reduced the band gap of the CdTe film due to the larger grain size. The photocurrent of photoelectrode based on high crystalline CdTe polycrystalline films after CdCl 2 treatment improved to 2.97 mA/cm 2 , indicating a potential application in photovoltaic devices

  4. Synchronous photoelectrical observations of flare stars in the visible and near infrared ranges

    Bruevich, V.V.; Kilyachkov, N.N.; Shevchenko, V.S.; Burnashov, V.I.; Grinin, V.P.; Koryshev, V.V.; Shakhovskaya, N.I.

    1980-01-01

    The results of synchronous photoelectrical observations of the AD Leo and EV Lac flare stars made in 1975 in the Crimea in B-filter and in the near infrared region (i-band, lambdasub(ef) approximately 0.85 μm) and the observations of the UV Cet and EV Lac stars made in 1976 in the Astronomical Institute Uzbek SSR in three passbands: U, isub(TiO)(lambdasub(ef)=0.71 μ) and isub(C)(lambdasub(ef)=0.80μm) are given. Practically all strong flares in the visible spectral range were followed by the IR-flares. In about 70% of the cases the predicted infrared negative preflares were observed. The amplitudes (in erg/s) of the negative flares are comparable with the amplitude of the optical flares. The analysis of the observed data shows that: a) the amplitudes and the energies of the positive IR flares are in average the larger the stronger is the optical flare; b) the amplitudes of the negative IR preflares are on the contrary the smaller the stronger is the optical flare; c) there are infrared flares the main energy out of which takes place in the infrared range of wavelengths; d) The U-i color shows a positive correlation with the amplitude of the flare in U: the stronger is the flare the bluer is its radiation

  5. The sandwich InGaAs/GaAs quantum dot structure for IR photoelectric detectors

    Moldavskaya, L. D.; Vostokov, N. V.; Gaponova, D. M.; Danil'tsev, V. M.; Drozdov, M. N.; Drozdov, Yu. N.; Shashkin, V. I.

    2008-01-01

    A new possibility for growing InAs/GaAs quantum dot heterostructures for infrared photoelectric detectors by metal-organic vapor-phase epitaxy is discussed. The specific features of the technological process are the prolonged time of growth of quantum dots and the alternation of the low-and high-temperature modes of overgrowing the quantum dots with GaAs barrier layers. During overgrowth, large-sized quantum dots are partially dissolved, and the secondary InGaAs quantum well is formed of the material of the dissolved large islands. In this case, a sandwich structure is formed. In this structure, quantum dots are arranged between two thin layers with an increased content of indium, namely, between the wetting InAs layer and the secondary InGaAs layer. The height of the quantum dots depends on the thickness of the GaAs layer grown at a comparatively low temperature. The structures exhibit intraband photoconductivity at a wavelength around 4.5 μm at temperatures up to 200 K. At 90 K, the photosensitivity is 0.5 A/W, and the detectivity is 3 x 10 9 cm Hz 1/2 W -1

  6. Asymmetric photoelectric property of transparent TiO2 nanotube films loaded with Au nanoparticles

    Wang, Hui; Liang, Wei; Liu, Yiming; Zhang, Wanggang; Zhou, Diaoyu; Wen, Jing

    2016-01-01

    Highlights: • Highly transparent films of TiO 2 nanotube arrays were directly fabricated on FTO glasses. • Semitransparent TNT-Au composite films were obtained and exhibited excellent photoelectrocatalytic ability. • Back-side of TNT-Au composite films was firstly irradiated and tested to compare with front-side of films. - Abstract: Semitransparent composite films of Au loaded TiO 2 nanotubes (TNT-Au) were prepared by sputtering Au nanoparticles on highly transparent TiO 2 nanotubes films, which were fabricated directly on FTO glasses by anodizing the Ti film sputtered on the FTO glasses. Compared with pure TNT films, the prepared TNT-Au films possessed excellent absorption ability and high photocurrent response and improved photocatalytic activity under visible-light irradiation. It could be concluded that Au nanoparticles played important roles in improving the photoelectrochemical performance of TNT-Au films. Moreover, in this work, both sides of TNT-Au films were researched and compared owing to theirs semitransparency. It was firstly found that the photoelectric activity of TNT-Au composite films with back-side illumination was obviously superior to front-side illumination.

  7. Photoelectrical Stimulation of Neuronal Cells by an Organic Semiconductor-Electrolyte Interface.

    Abdullaeva, Oliya S; Schulz, Matthias; Balzer, Frank; Parisi, Jürgen; Lützen, Arne; Dedek, Karin; Schiek, Manuela

    2016-08-23

    As a step toward the realization of neuroprosthetics for vision restoration, we follow an electrophysiological patch-clamp approach to study the fundamental photoelectrical stimulation mechanism of neuronal model cells by an organic semiconductor-electrolyte interface. Our photoactive layer consisting of an anilino-squaraine donor blended with a fullerene acceptor is supporting the growth of the neuronal model cell line (N2A cells) without an adhesion layer on it and is not impairing cell viability. The transient photocurrent signal upon illumination from the semiconductor-electrolyte layer is able to trigger a passive response of the neuronal cells under physiological conditions via a capacitive coupling mechanism. We study the dynamics of the capacitive transmembrane currents by patch-clamp recordings and compare them to the dynamics of the photocurrent signal and its spectral responsivity. Furthermore, we characterize the morphology of the semiconductor-electrolyte interface by atomic force microscopy and study the stability of the interface in dark and under illuminated conditions.

  8. Optical and photoelectrical studies of gold nanoparticle-decorated C{sub 60} films

    Dmitruk, N.L., E-mail: dmitruk@isp.kiev.u [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Borkovskaya, O.Yu.; Mamykin, S.V.; Naumenko, D.O. [Institute for Physics of Semiconductors, National Academy of Sciences of Ukraine, 45 Nauki Prospect, Kyiv 03028 (Ukraine); Meza-Laguna, V. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior, Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Basiuk Golovataya-Dzhymbeeva, E.V. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico (UNAM), Circuito exterior S/N Ciudad Universitaria, A. P. 70-186, C. P. 04510 Mexico D.F. (Mexico); Lee, I. Puente [Facultad de Quimica, UNAM, Circuito de la Investigacion Cientifica, Ciudad Universitaria, 04510 Mexico D.F. (Mexico)

    2010-01-01

    Optical and photoelectrical studies were performed on octane-1,8-dithiol cross-linked fullerene films, with supported gold nanoparticles (C{sub 60}-DT-Au). According to high-resolution transmission electron microscopy observations, the average size of obtained gold nanoparticles was about 5 nm, and the shape was spherical. The comparative investigation of optical properties of pristine and cross-linked with octane-1,8-dithiol C{sub 60} films, decorated with gold nanoparticles, found the difference in the extinction coefficient spectra, which was observed also in the photocurrent spectra of barrier heterostructure Au/C{sub 60}/Si. The analysis of dark current-voltage characteristics for Au/C{sub 60}/Si heterostructures showed that the model for them includes the barrier at the C{sub 60}/Si interface and internal barriers in the C{sub 60} layer, caused by the trapping centers. The hopping mechanism of the current transport in the C{sub 60} layer was supplemented with the Poole-Frenkel emission process on these centers, with the barrier height greater for the fullerene C{sub 60} film cross-linked with octane-1,8-dithiol.

  9. Optimal design of a high accuracy photoelectric auto-collimator based on position sensitive detector

    Yan, Pei-pei; Yang, Yong-qing; She, Wen-ji; Liu, Kai; Jiang, Kai; Duan, Jing; Shan, Qiusha

    2018-02-01

    A kind of high accuracy Photo-electric auto-collimator based on PSD was designed. The integral structure composed of light source, optical lens group, Position Sensitive Detector (PSD) sensor, and its hardware and software processing system constituted. Telephoto objective optical type is chosen during the designing process, which effectively reduces the length, weight and volume of the optical system, as well as develops simulation-based design and analysis of the auto-collimator optical system. The technical indicators of auto-collimator presented by this paper are: measuring resolution less than 0.05″; a field of view is 2ω=0.4° × 0.4° measuring range is +/-5' error of whole range measurement is less than 0.2″. Measuring distance is 10m, which are applicable to minor-angle precise measuring environment. Aberration analysis indicates that the MTF close to the diffraction limit, the spot in the spot diagram is much smaller than the Airy disk. The total length of the telephoto lens is only 450mm by the design of the optical machine structure optimization. The autocollimator's dimension get compact obviously under the condition of the image quality is guaranteed.

  10. Asymmetric photoelectric property of transparent TiO{sub 2} nanotube films loaded with Au nanoparticles

    Wang, Hui [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); College of Applied Science, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Liang, Wei, E-mail: 986903124@qq.com [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China); Liu, Yiming; Zhang, Wanggang; Zhou, Diaoyu; Wen, Jing [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024 (China); Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology, Ministry of Education, Taiyuan, Shanxi 030024 (China)

    2016-11-15

    Highlights: • Highly transparent films of TiO{sub 2} nanotube arrays were directly fabricated on FTO glasses. • Semitransparent TNT-Au composite films were obtained and exhibited excellent photoelectrocatalytic ability. • Back-side of TNT-Au composite films was firstly irradiated and tested to compare with front-side of films. - Abstract: Semitransparent composite films of Au loaded TiO{sub 2} nanotubes (TNT-Au) were prepared by sputtering Au nanoparticles on highly transparent TiO{sub 2} nanotubes films, which were fabricated directly on FTO glasses by anodizing the Ti film sputtered on the FTO glasses. Compared with pure TNT films, the prepared TNT-Au films possessed excellent absorption ability and high photocurrent response and improved photocatalytic activity under visible-light irradiation. It could be concluded that Au nanoparticles played important roles in improving the photoelectrochemical performance of TNT-Au films. Moreover, in this work, both sides of TNT-Au films were researched and compared owing to theirs semitransparency. It was firstly found that the photoelectric activity of TNT-Au composite films with back-side illumination was obviously superior to front-side illumination.

  11. Photoelectric schlieren method used to study the properties of diesel engine injection systems

    Reznicek, R.

    1987-01-01

    The time dependence of the fuel flow rate issuing from the injector nozzle represents very important information concerning the properties of Diesel engine injection systems. By analysing the delivery rate, it is possible to judge a new design, and the modifications and adjustments of Diesel engine injection systems. A number of devices for measuring the delivery rate, frequently founded on mechanical principles, have also been constructed. Mechanical methods are laborious, require complicated measuring instruments, and the analysis of the results is quite tedious. For investigating the delivery rate, one can also use the intensity of the luminous flux of the light ray which is intersected, and consequently its intensity decreased, by the flow of the delivered fuel. The schlieren method can be used for this purpose, employing a thin beam of parallel light rays and a photoelectric sensor placed immediately beyond the cut-off slit. After adjustment and calibration, the variations of the original electric signal represent the time variation of the delivery rate by the nozzle

  12. Electrical and photoelectrical properties of poly(phenyl azomethine furane) thin films devices

    Sharma, G.D. [J.N.V. Univ., Jodhpur (India). Dept. of Phys.; Sandogaker, S.G. [J.N.V. Univ., Jodhpur (India). Dept. of Phys.; Roy, M.S. [Camouflage Division, Defence Laboratory, Jodhpur (Raj.) (India)

    1996-05-15

    Poly(phenyl azomethine furane) (PPAF), a conjugated system of poly-Schiff base was synthesised by condensation of p-aminobenzene with furane-2-aldehyde. Oxidative polymerization was conducted at 0-5 C temperature, and the polymer formed was found to be soluble in common organic solvent. Optical properties were studied in the UV-visible-IR region. Electrical and photoelectrical properties of Al/PPAF/ITO and Ag/PPAF/ITO sandwich devices were investigated by measuring the steady state photocurrent resulting from illumination. The device Al/PPAF/ITO shows a Schottky barrier at the Al-PPAF interface and ohmic contact at ITO-PPAF interface. The device Ag/PPAF/ITO shows ohmic contact at both interfaces. This behaviour has been explained in terms of P-type conductivity of the PPAF and the formation of a Schottky barrier with the low work function electrode and ohmic contact with the higher work function electrode. Under low forward bias voltage (ITO positive) ohmic conduction is observed while at higher voltage there is space charge-limited conduction (SCLC). The dependence of the photo short-circuit current on illumination intensity was discussed in detail. The C-V characteristics of both devices have also been analysed. (orig.)

  13. Oxide properties of autoclaved zircaloy cladding tubes investigated by the photoelectric polarization method

    Nystrand, A.C.

    2000-06-01

    Corrosion of zirconium alloys is an important lifetime limiting factor for the nuclear reactor fuel. The corrosion resistance of a metal is highly dependent on the ability of the surface metal oxide to transport electrons and ions, which is related to the stoichiometry of the oxide and the oxide defect concentration. The Photoelectric Polarization Method (PEP) is a structure sensitive method which earlier has been investigated as a possible method to study the defect structure in zirconium oxides. The purpose of the following work is, by using more optimized experimental equipment, to verify if the PEP method is a suitable method to study the defect structure in zirconium oxides and to predict the corrosion resistance for different zirconium alloys. The conclusions from the experiments are as follows: - The modifications of the experimental setup by means of a new source of light (deuterium lamp) and a new oscilloscope with an amplifier gave distinct Vpep signals. - The photoresponse is negative for all types of cladding and under all kind of oxidation regimes and hence the oxide is a n-type semiconductor with deficiency of oxygen. - The method needs to be verified by testing semiconductors with a known defect concentration

  14. High Velocity Spectroscopic Binary Orbits from Photoelectric Radial Velocities: BD+20 5152, a Possible Triple System

    Sperauskas J.

    2010-12-01

    Full Text Available The spectroscopic orbit of a high proper motion star, BD+20 5152, is calculated from 34 CORAVEL-type radial velocity measurements. The star has a slightly eccentric orbit with a period of 5.70613 d, half-amplitude of 47.7 km/s and eccentricity of 0.049. The center-of-mass velocity of the system is -24.3 km/s. BD+20 5152 seems to be a triple system consisting of a G8 dwarf as a primary component and of two K6-M0 dwarfs as secondary and tertiary components. This model is based on the analysis of its UBVRI and JHK magnitudes. According to the SuperWASP photometry, spots on the surface of the primary are suspected. The excessive brightness in the Galex FUV and NUV magnitudes and a non-zero eccentricity suggest the age of this system to be less than 1 Gyr.

  15. Polarimetry and photometry of M87: is the jet fading

    Warren-Smith, R F; King, D J; Scarrott, S M [Durham Univ. (UK). Dept. of Physics

    1984-09-15

    Optical linear polarization mapping and photometry of M87 is presented in B and R wavebands. The results indicate significant polarization in the galactic nucleus. Polarization in the jet in B is consistent with other recent maps obtained for this area in blue light and no significant variation with wavelength between B and R wavebands is found. The spectral index of the jet radiation is measured to be S=-1.65+-0.2 over the wavelength range observed. Comparison of the integrated B magnitude of the jet with previous independent measurements over the period 1934-80 suggests that the jet is variable and has been fading more or less uniformly by about 0.8 mag per decade between 1964 and 1980.

  16. Infrared polarimetry and photometry of BL Lac objects

    Impey, C D; Brand, P W.J.L. [Edinburgh Univ. (UK); Wolstencroft, R D; Williams, P M [Royal Observatory, Edinburgh (UK)

    1982-07-01

    Infrared polarimetry and photometry have been obtained for a sample of 18 BL Lac objects. The data covers a period of one year and is part of a continuing monitoring programme; all observations were in the J,H and K wavebands. Large and variable degrees of polarization are a common property of the sample. Two BL Lac objects show wavelength-dependent polarization, with the polarization increasing towards shorter wavelengths, and two objects show evidence for position angle rotations over a five-day period. The relationship between changes in polarized and total flux is also discussed. The BL Lac objects cover an enormous range of infrared luminosity; the three most luminous having Lsub(IR) > 10/sup 46/ erg s/sup -1/ and the other end of the range having infrared luminosities similar to normal elliptical galaxies. These are the first published infrared polarimetric observations for eight of the sample.

  17. Polarimetry and photometry of the AM Her polar

    Efimov, Yu S; Shakhovskoj, N M

    1982-01-01

    The results of the polarization observations and photometry of AM Her obtained during 11 nights from April to September 1978 are presented. The observations were carried out in V spectral region with time resolution of about four minutes. The results of measurements are in agreement with previous observations. The polarization maximum, being mostly on the 1.3 % level, was rising up to 2 % only at an active state of the star. No correlation was found between rapid variations of light and linear polarization at an inactive state of the star. The phase dependence of mean polarization parameters is revealed. The displaced dipole magnetic field with different strength on the poles is assumed for the polar model to interpret the vector diagram of polarization.

  18. Testbed for High-Acuity Imaging and Stable Photometry

    Gregory, James

    This proposal from MIT Lincoln Laboratory (LL) accompanies the NASA/APRA proposal enti-tled THAI-SPICE: Testbed for High-Acuity Imaging - Stable Photometry and Image-Motion Compensa-tion Experiment (submitted by Eliot Young, Southwest Research Institute). The goal of the THAI-SPICE project is to demonstrate three technologies that will help low-cost balloon-borne telescopes achieve diffraction-limited imaging: stable pointing, passive thermal stabilization and in-flight monitoring of the wave front error. This MIT LL proposal supplies a key element of the pointing stabilization component of THAI-SPICE: an electronic camera based on an orthogonaltransfer charge-coupled device (OTCCD). OTCCD cameras have been demonstrated with charge-transfer efficiencies >0.99999, noise of 90%. In addition to supplying a camera with an OTCCD detector, MIT LL will help with integration and testing of the OTCCD with the THAI-SPICE payload’s guide camera.

  19. Near-infrared photometry of HDE 245770 (A 0535 + 26)

    Persi, P.; Ferrari-Toniolo, M.; Spada, G.; Conti, G.; Di Benedetto, P.; Tanzi, E.G.; Tarenghi, M.

    1979-01-01

    A derivation is presented of the optical-infrared energy distribution of the OBe star HDE 245770, the optical counterpart of the transient X-ray source A 0535 + 26, using infrared observations made in the period 1976 November - 1977 March and UBV photometry obtained by other workers in 1976 November. An infrared excess is evident with flux density Ssub(ν) varies as νsup(approximately 0.6). The excess is explained in terms of thermal free-free emission from an ionized gaseous envelope around the OBe star. Assuming a matter outflow through the envelope with uniform velocity of a few hundred km/s, a value is obtained for the mass loss rate in HDE 245770 of about 10 -6 solar masses/yr. (author)

  20. Results of the 2017 Mexican Asteroid Photometry Campaign - Part 1

    Sada, Pedro; Loera-Gonzalez, Pablo; Olguin, Lorenzo; Saucedo-Morales, Julio C.; Ayala-Gómez, Sandra A.; Garza, Jaime R.

    2018-04-01

    We report the results for the first semester of the 2017 Mexican Asteroid Photometry Campaign. Asteroid 1218 Aster (synodic period of 3.1581 ± 0.0002 h and amplitude of 0.35 mag) was well observed and showed slight variations of its lightcurve at the end of the seven week observing window. An uncertain, but long, period of 93.23 ± 0.02 h and amplitude of 0.36 mag were estimated for 2733 Hamina from sparse data. Asteroid 8443 Svecica was also well observed and yielded a period of 20.9905 ± 0.0015 h and amplitude of 0.65 mag. Observations of NEA (143404) 2003 BD44 also resulted in an uncertain and long period of 78.617 ± 0.009 h and amplitude of 0.66 mag with a sparsely covered lightcurve.

  1. FRAM telescope - monitoring of atmospheric extinction and variable star photometry

    Jurysek, J.; Honkova, K.; Masek, M.

    2015-02-01

    The FRAM (F/(Ph)otometric Robotic Atmospheric Monitor) telescope is a part of the Pierre Auger Observatory (PAO) located near town Malargüe in Argentina. The main task of the FRAM telescope is the continuous night - time monitoring of the atmospheric extinction and its wavelength dependence. The current methodology of the measurement of a atmospheric extinction and for instrumentation properties also allows simultaneous observation of other interesting astronomical targets. The current observations of the FRAM telescope are focused on the photometry of eclipsing binaries, positional refinement of minor bodies of the Solar system and observations of optical counterparts of gamma ray bursts. In this contribution, we briefly describe the main purpose of the FRAM telescope for the PAO and we also present its current astrono mical observing program.

  2. uvbyHβ photometry of UV-bright stars

    Wade, B.R.; Smith, L.F.

    1985-01-01

    uvbyHβ photometry is presented for 90 stars taken from an early version of the Carnochan and Wilson catalogue (1983. Mon. Not. R. astr. Soc. 202,317) of stars that have very negative UV colours. Two have definite UV excesses, (HD 36629, and HD81307). Four early-B stars have UV colours too positive for their visible classification, and β-indices that indicate higher luminosities than appear possible on galactic distribution grounds. Six late-B stars appear to have discordant flux distributions for which there are no obvious explanations. It is suggested that the high population of subluminous stars derived by Carnochan and Wilson is the product of the statistical treatment used and the extreme patchiness in the interstellar absorption. (author)

  3. Applied photometry, radiometry, and measurements of optical losses

    Bukshtab, Michael

    2012-01-01

    Applied Photometry, Radiometry, and Measurements of Optical Losses reviews and analyzes physical concepts of radiation transfer, providing quantitative foundation for the means of measurements of optical losses, which affect propagation and distribution of light waves in various media and in diverse optical systems and components. The comprehensive analysis of advanced methodologies for low-loss detection is outlined in comparison with the classic photometric and radiometric observations, having a broad range of techniques examined and summarized: from interferometric and calorimetric, resonator and polarization, phase-shift and ring-down decay, wavelength and frequency modulation to pulse separation and resonant, acousto-optic and emissive - subsequently compared to direct and balancing methods for studying free-space and polarization optics, fibers and waveguides. The material is focused on applying optical methods and procedures for evaluation of transparent, reflecting, scattering, absorbing, and aggregat...

  4. A practical guide to lightcurve photometry and analysis

    Warner, Brian D

    2016-01-01

    For those with access to even a modest telescope and CCD camera, this new and improved guide delivers all the information needed to take part in the scientific study of asteroids and variable stars. New techniques in photometry continue to be refined, and expert Brian Warner covers the developing territory in detail for those both new and experienced. Updated to reflect changes in telescope and CCD technology, it also includes an expanded chapter on the analysis of asteroid lightcurves to cover some of the common pitfalls that lead to incorrect answers as well as how to discover an asteroid satellite via lightcurves. With this information, amateur astronomers can use commercially available equipment to determine the rotation rate, size, and shape of asteroids. Similarly, it is possible to discover the size, temperature, and orbits of stars in binary systems by using this powerful technique. Brian Warner yet again delivers all the material needed for readers to understand the theory, and avoid the practical pi...

  5. Time Resolved Precision Differential Photometry with OAFA's Double Astrograph

    González, E. P. A.; Podestá, F.; Podestá, R.; Pacheco, A. M.

    2018-01-01

    For the last 50 years, the Double Astrograph located at the Carlos U. Cesco station of the Observatorio Astronómico Félix Aguilar (OAFA), San Juan province, Argentina, was used for astrometric observations and research. The main programs involved the study of asteroid positions and proper motions of stars in the Southern hemisphere, being the latter a long time project that is near completion from which the SPM4 catalog is the most recent version (Girard et al. 2011). In this paper, new scientific applications in the field of photometry that can be accomplished with this telescope are presented. These first attempts show the potential of the instrument for such tasks.

  6. Asteroid models from photometry and complementary data sources

    Kaasalainen, Mikko [Department of Mathematics, Tampere University of Technology (Finland)

    2016-05-10

    I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multi-modal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data.

  7. Asteroid models from photometry and complementary data sources

    Kaasalainen, Mikko

    2016-01-01

    I discuss inversion methods for asteroid shape and spin reconstruction with photometry (lightcurves) and complementary data sources such as adaptive optics or other images, occultation timings, interferometry, and range-Doppler radar data. These are essentially different sampling modes (generalized projections) of plane-of-sky images. An important concept in this approach is the optimal weighting of the various data modes. The maximum compatibility estimate, a multi-modal generalization of the maximum likelihood estimate, can be used for this purpose. I discuss the fundamental properties of lightcurve inversion by examining the two-dimensional case that, though not usable in our three-dimensional world, is simple to analyze, and it shares essentially the same uniqueness and stability properties as the 3-D case. After this, I review the main aspects of 3-D shape representations, lightcurve inversion, and the inclusion of complementary data.

  8. Characterizing exoplanets atmospheres with space photometry at optical wavelengths

    Parmentier Vivien

    2015-01-01

    Full Text Available Space photometry such as performed by Kepler and CoRoT provides exoplanets radius and phase curves with an exquisite precision. The phase curve constrains the longitudinal variation of the albedo and shed light on the horizontal distribution of clouds. The planet radius constraints thermal evolution of the planet, potentially unveiling its atmospheric composition. We present how the atmospheric circulation can affect the cloud distribution of three different planets, HD209458b, Kepler-7b and HD189733b based on three-dimensional models and analytical calculations. Then we use an analytical atmospheric model coupled to a state-of-the-art interior evolution code to study the role of TiO in shaping the thermal evolution and final radius of the planet.

  9. Photometry of High-Redshift Gravitationally Lensed Type Ia Supernovae

    Haynie, Annastasia

    2018-01-01

    Out of more than 1100 well-identified Type Ia Supernovae, only roughly 10 of them are at z> 1.5. High redshift supernovae are hard to detect but this is made easier by taking advantage of the effects of gravitational lensing, which magnifies objects in the background field of massive galaxy clusters. Supernova Nebra (z= ~1.8), among others, was discovered during observations taken as part of the RELICS survey, which focused on fields of view that experience strong gravitational lensing effects. SN Nebra, which sits behind galaxy cluster Abell 1763, is magnified and therefore appears closer and easier to see than with HST alone. Studying high-redshift supernovae like SN Nebra is an important step towards creating cosmological models that accurately describe the behavior of dark energy in the early Universe. Recent efforts have been focused on improving photometry and the building and fitting of preliminary light curves.

  10. SPITZER IRAC PHOTOMETRY FOR TIME SERIES IN CROWDED FIELDS

    Novati, S. Calchi; Beichman, C. [NASA Exoplanet Science Institute, MS 100-22, California Institute of Technology, Pasadena, CA 91125 (United States); Gould, A.; Fausnaugh, M.; Gaudi, B. S.; Pogge, R. W.; Wibking, B.; Zhu, W.; Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Yee, J. C. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Bryden, G.; Henderson, C. B.; Shvartzvald, Y. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Carey, S. [Spitzer, Science Center, MS 220-6, California Institute of Technology, Pasadena, CA (United States); Udalski, A.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Collaboration: Spitzer team; OGLE group; and others

    2015-12-01

    We develop a new photometry algorithm that is optimized for the Infrared Array Camera (IRAC) Spitzer time series in crowded fields and that is particularly adapted to faint or heavily blended targets. We apply this to the 170 targets from the 2015 Spitzer microlensing campaign and present the results of three variants of this algorithm in an online catalog. We present detailed accounts of the application of this algorithm to two difficult cases, one very faint and the other very crowded. Several of Spitzer's instrumental characteristics that drive the specific features of this algorithm are shared by Kepler and WFIRST, implying that these features may prove to be a useful starting point for algorithms designed for microlensing campaigns by these other missions.

  11. Gaia, an all-sky survey for standard photometry

    Carrasco, J. M.; Weiler, M.; Jordi, C.; Fabricius, C.

    2017-03-01

    Gaia ESA's space mission (launched in 2013) includes two low resolution spectroscopic instruments (one in the blue, BP, and another in the red, RP, wavelength domains) to classify and derive the astrophysical parameters of the observed sources. As it is well known, Gaia is a full-sky unbiased survey down to about 20th magnitude. The scanning law yields a rather uniform coverage of the sky over the full extent (a minimum of 5 years) of the mission. Gaia data reduction is a global one over the full mission. Both sky coverage and data reduction strategy ensure an unprecedented all-sky homogeneous spectrophotometric survey. Certainly, that survey is of interest for current and future on-ground and space projects, like LSST, PLATO, EUCLID and J-PAS/J-PLUS among others. These projects will benefit from the large amount (more than one billion) and wide variety of objects observed by Gaia with good quality spectrophotometry. Synthetic photometry derived from Gaia spectrophotometry for any passband can be used to expand the set of standard sources for these new instruments to come. In the current Gaia data release scenario, BP/RP spectrophotometric data will be available in the third release (in 2018, TBC). Current preliminary results allow us to estimate the precision of synthetic photometry derived from the Gaia data. This already allows the preparation of the on-going and future surveys and space missions. We discuss here the exploitation of the Gaia spectrophotometry as standard reference due to its full-sky coverage and its expected photometric uncertainties derived from the low resolution Gaia spectra.

  12. Binary-induced magnetic activity?. Time-series echelle spectroscopy and photometry of HD 123351 = CZ CVn

    Strassmeier, K. G.; Carroll, T. A.; Weber, M.; Granzer, T.; Bartus, J.; Oláh, K.; Rice, J. B.

    2011-11-01

    Context. Multi-wavelength time-series observations with high cadence and long duration are needed to resolve and understand the many variations of magnetically active late-type stars, which is an approach often used to observe the Sun. Aims: We present a first and detailed study of the bright and active K0IV-III star HD 123351. Methods: We acquired a total of 955 high-resolution STELLA echelle spectra during the years 2006-2010 and a total of 2260 photometric VIC data points during 1998-2010. These data are complemented by some spectra from CFHT and KPNO. Results: The star is found to be a single-lined spectroscopic binary with a period of 147.8919 ± 0.0003 days and a large eccentricity of e = 0.8086 ± 0.0001. The rms of the orbital solution is just 47 m s-1, making it the most precise orbit ever obtained for an active binary system. The rotation period is constrained from long-term photometry to be 58.32 ± 0.01 days. It shows that HD 123351 is a very asynchronous rotator, rotating five times slower than the expected pseudo-synchronous value. Two spotted regions persisted throughout the 12 years of our observations. We interpret them as active longitudes on a differentially rotating surface with a ΔP/P of 0.076. Four years of Hα, Ca ii H&K and He i D3 monitoring identifies the same main periodicity as the photometry but dynamic spectra also indicate that there is an intermittent dependence on the orbital period, in particular for Ca ii H&K in 2008. Line-profile inversions of a pair of Zeeman sensitive/insensitive iron lines yield an average surface magnetic-flux density of 542 ± 72 G. The time series for 2008 is modulated by the stellar rotation as well as the orbital motion, such that the magnetic flux is generally weaker during times of periastron and that the chromospheric emissions vary in anti-phase with the magnetic flux. We also identify a broad and asymmetric lithium line profile and measure an abundance of log n(Li) = 1.70 ± 0.05. The star

  13. Photoelectric properties of thin films from the CdS-Ag2 S system

    Ristova-Lipanovikj, Mimoza

    1996-01-01

    Three different methods for preparation of thin films of CdS-Ag 2 S system are presented. Those methods are modified from the already existing methods of chemical deposition, and the method of spray pyrolysis, both widely utilized for preparation of wide range of binary, ternary and quaternary semiconductor thin films. The atomic absorption method was applied for quantitative analysis of the samples. The crystal structure of the thin films was studied by X-ray diffraction, while their morphology and the texture was analyzed from the microphotographs, taken on the samples by an optical microscope, in transmitted light. An extensive research was undertaken, to improve the crystallinity of the samples, by performing a post preparation thermal treatment. Photoelectric as well as some other physical properties were studied. VIS and NIR transmission spectra were recorded. The optical band gaps for various thin films containing different portions of Ag and Cd in the system, were evaluated. Spectral dependence of the photoconductivity was recorded. The optical band gaps were determined from the positions of the corresponding maxima of the photoconductivity. From the curves of the time relaxation of the photoconductivity, the carrier life times were calculates. Measurements of the thermal dependence of the resistivity on various samples were performed. Based on the extensive experimental research, the most convenient composition for PV application was selected. For the sake of comparison, two different types of PV cells were manufactured, Sn O 2 :F/CdS:Ag-Sn x S, and Sn O 2 :F/CdS-Sn x S, in order to study the influence of the silver content in the CdS. The plots of I-V and C-V characteristics are presented, and the parameters of the solar cells, were determined and taken in a relation with the content of the silver on the CdS. Finally, some directions of a possible future experimental and theoretical research in this field are given, based on the conclusions made. (author)

  14. ZnO/Cu/ZnO multilayer films: Structure optimization and investigation on photoelectric properties

    Liu Xiaoyu; Li Yingai; Liu Shi; Wu Honglin; Cui Haining

    2012-01-01

    A series of ZnO/Cu/ZnO multilayer films has been fabricated from zinc and copper metallic targets by simultaneous RF and DC magnetron sputtering. Numerical simulation of the optical properties of the multilayer films has been carried out in order to guide the experimental work. The influences of the ZnO and Cu layer thicknesses, and of O 2 /Ar ratio on the photoelectric and structural properties of the films were investigated. The optical and electrical properties of the multilayers were studied by optical spectrometry and four point probe measurements, respectively. The structural properties were investigated using X-ray diffraction. The performance of the multilayers as transparent conducting coatings was compared using a figure of merit. In experiments, the thickness of the ZnO layers was varied between 4 and 70 nm and those of Cu were between 8 and 37 nm. The O 2 /Ar ratios range from 1:5 to 2:1. Low sheet resistance and high transmittance were obtained when the film was prepared using an O 2 /Ar ratio of 1:4 and a thickness of ZnO (60 nm)/Cu (15 nm)/ZnO (60 nm). - Highlights: ► ZnO/Cu/ZnO films were fabricated from zinc and copper targets by sputtering. ► Transmittance reaches maximum when top and bottom ZnO thicknesses are nearly equal. ► Sheet resistance increases with increasing ZnO layer thickness. ► Variation in sheet resistance with oxygen/argon ratio is due to interface effect.

  15. Variable interstellar radiation fields in simulated dwarf galaxies: supernovae versus photoelectric heating

    Hu, Chia-Yu; Naab, Thorsten; Glover, Simon C. O.; Walch, Stefanie; Clark, Paul C.

    2017-10-01

    We present high-resolution hydrodynamical simulations of isolated dwarf galaxies including self-gravity, non-equilibrium cooling and chemistry, interstellar radiation fields (ISRF) and shielding, star formation, and stellar feedback. This includes spatially and temporally varying photoelectric (PE) heating, photoionization, resolved supernova (SN) blast waves and metal enrichment. A new flexible method to sample the stellar initial mass function allows us to follow the contribution to the ISRF, the metal output and the SN delay times of individual massive stars. We find that SNe play the dominant role in regulating the global star formation rate, shaping the multiphase interstellar medium (ISM) and driving galactic outflows. Outflow rates (with mass-loading factors of a few) and hot gas fractions of the ISM increase with the number of SNe exploding in low-density environments where radiative energy losses are low. While PE heating alone can suppress star formation as efficiently as SNe alone can do, it is unable to drive outflows and reproduce the multiphase ISM that emerges naturally whenever SNe are included. We discuss the potential origins for the discrepancy between our results and another recent study that claimed that PE heating dominates over SNe. In the absence of SNe and photoionization (mechanisms to disperse dense clouds), the impact of PE heating is highly overestimated owing to the (unrealistic) proximity of dense gas to the radiation sources. This leads to a substantial boost of the infrared continuum emission from the UV-irradiated dust and a far-infrared line-to-continuum ratio too low compared to observations.

  16. The Schrödinger Equation, the Zero-Point Electromagnetic Radiation, and the Photoelectric Effect

    França, H. M.; Kamimura, A.; Barreto, G. A.

    2016-04-01

    A Schrödinger type equation for a mathematical probability amplitude Ψ( x, t) is derived from the generalized phase space Liouville equation valid for the motion of a microscopic particle, with mass M and charge e, moving in a potential V( x). The particle phase space probability density is denoted Q( x, p, t), and the entire system is immersed in the "vacuum" zero-point electromagnetic radiation. We show, in the first part of the paper, that the generalized Liouville equation is reduced to a simpler Liouville equation in the equilibrium limit where the small radiative corrections cancel each other approximately. This leads us to a simpler Liouville equation that will facilitate the calculations in the second part of the paper. Within this second part, we address ourselves to the following task: Since the Schrödinger equation depends on hbar , and the zero-point electromagnetic spectral distribution, given by ρ 0{(ω )} = hbar ω 3/2 π 2 c3, also depends on hbar , it is interesting to verify the possible dynamical connection between ρ 0( ω) and the Schrödinger equation. We shall prove that the Planck's constant, present in the momentum operator of the Schrödinger equation, is deeply related with the ubiquitous zero-point electromagnetic radiation with spectral distribution ρ 0( ω). For simplicity, we do not use the hypothesis of the existence of the L. de Broglie matter-waves. The implications of our study for the standard interpretation of the photoelectric effect are discussed by considering the main characteristics of the phenomenon. We also mention, briefly, the effects of the zero-point radiation in the tunneling phenomenon and the Compton's effect.

  17. The application of full spectrum gamma-gamma techniques to density/photoelectric cross section logging

    Minette, D.C.; Hubner, B.G.; Koudelka, J.C.; Schmidt, M.

    1986-01-01

    The Compensated Z-Densilog instrument is a new full spectrum gamma-gamma logging instrument, measuring the density and photoelectric cross section (Pe) of the formation. This instrument represents an advancement over present instruments in that the observed gamma spectrum is sent to the surface as a full 256-channel spectrum instead of count rates in a few energy gates. This advancement is made possible by the use of high speed digital electronics which are protected from the high temperatures observed downhole by custom-built flasks. In this paper, the new advanced electronics are considered in some detail. This consideration includes a comparison of full spectrum data acquisition with the multiple discriminator window technique, which is the foundation of the ''few gate'' method. Both of these methods are critiqued based upon electronic stability and the information obtained. The full spectrum provided by high speed electronics facilitates a much more sophisticated data analysis. This data analysis, based on phenomenological model of the instrument (Minette, 1984), includes real time compensation for changes in detector gain and crystal resolution. It also includes a ''four-dimensional'' rib-spine plot, which separates the compensation for mudcake density from the compensation for the Pe of the formation and the mudcake. Also included in the software are real time error minimization and real time decision-making techniques. These techniques maximize the sensitivity of the instrument to the density and Pe of the formation and minimize error due to statistical fluctuations. Gain and resolution compensation completes the data analysis. This compensation virtually eliminates density and Pe errors caused by changing gain and resolution

  18. Photoelectric characteristics of metal-Ga{sub 2}O{sub 3}-GaAs structures

    Kalygina, V. M., E-mail: Kalygina@ngs.ru; Vishnikina, V. V.; Petrova, Yu. S.; Prudaev, I. A.; Yaskevich, T. M. [National Research Tomsk State University (Russian Federation)

    2015-03-15

    We investigate the effect of thermal annealing in argon and of oxygen plasma processing on the photoelectric properties of GaAs-Ga{sub 2}O{sub 3}-Me structures. Gallium-oxide films are fabricated by photostimulated electrochemical oxidation of epitaxial gallium-arsenide layers with n-type conductivity. The as-deposited films were amorphous, but their processing in oxygen plasma led to the nucleation of β-Ga{sub 2}O{sub 3} crystallites. The unannealed films are nontransparent in the visible and ultraviolet (UV) ranges and there is no photocurrent in structures based on them. After annealing at 900°C for 30 min, the gallium-oxide films contain only β-Ga{sub 2}O{sub 3} crystallites and become transparent. Under illumination of the Ga{sub 2}O{sub 3}-GaAs structures with visible light, the photocurrent appears. This effect can be attributed to radiation absorption in GaAs. The photocurrent and its voltage dependence are determined by the time of exposure to the oxygen plasma. In the UV range, the sensitivity of the structures increases with decreasing radiation wavelength, starting at λ ≤ 230 nm. This is due to absorption in the Ga{sub 2}O{sub 3} film. Reduction in the structure sensitivity with an increase in the time of exposure to oxygen plasma can be caused by the incorporation of defects both at the Ga{sub 2}O{sub 3}-GaAs interface and in the Ga{sub 2}O{sub 3} film.

  19. B and V photometry and analysis of the eclipsing binary RZ CAS

    Riazi, N.; Bagheri, M. R.; Faghihi, F.

    1994-01-01

    Photoelectric light curves of the eclipsing binary RZ Cas are presented for B and V filters. The light curves are analyzed for light and geometrical elements, starting with a previously suggested preliminary method. The approximate results thus obtained are then optimised through the Wilson-Devinney computer programs.

  20. Photometry and position observations of Saturnian satellites during their mutual eclipses and occultations in 1995 performed at the Observatories in Russia and Kazakhstan

    Emelianov, N. V.; Irsmambetova, T. R.; Kiseleva, T. P.; Tejfel, V. G.; Vashkovjak, S. N.; Glushkova, E. A.; Kornilov, V. G.; Charitonova, G. A.

    1999-10-01

    Photometry of mutual eclipses and occultations of planetary satellites is a powerful technique to explore these bodies. Observations of these rare events are a source of much precise information. In 1995 the Celestial Mechanics Department of the Sternberg Astronomical Institute (SAI) has organized the observations of mutual eclipses and occultations of Saturnian satellites on a number of observatories of the Commonwealth of Independent States (CIS) -- the former Soviet Union (FSU). The ephemerides of satellites and their observing conditions have been computed beforehand and mailed these data to many observatories of CIS. The Crimean laboratory (CL) of the Sternberg Astronomical Institute, two observatories of the Fesenkov Astrophysical Institute of the Academy of Sciences of the Republic of Kazakhstan (FAI AS RK) in Almaty, and the Main Astronomical Observatory of Russian Academy of Sciences (MAO RAS) in Pulkovo took part in observations. A photoelectric photometer was used in CL of SAI, a CCD was employed to secure satellite images in FAI AS RK, and both CCD and photographic plates were used in MAO RAS. As a result of this observing campaign, photometric data and light curves were obtained for three mutual eclipses and occultations of Saturnian satellites. A number of position observations made allowed us to measure relative coordinates of satellites. Astrometric information has already been derived from photometric data. The mutual apparent positions of satellites were calculated with an accuracy of 0farcs 002 - 0farcs 003. In this paper observations are described and the parameters characterizing the observed phenomena are given. The results of observations are available in electronic form. This work supported by the Russian Foundation for Basic Research, projects Nos. 95-02-05042, 97-02-16551. Results of observations available in electronic form at CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

  1. Three-colour photometry of four suspected double-mode cepheids

    Pike, C.D.; Andrews, P.J.

    1979-01-01

    UBV photometry of the cepheids DY Car, EY Car, FZ Car and TZ Mus covering several periods show no evidence for the variable light curves to be expected if they were in fact double-mode cepheids. (author)

  2. Stellar photometry with the Wide Field/Planetary Camera of the Hubble Space Telescope

    Holtzman, J.A.

    1990-01-01

    Simulations of Wide Field/Planetary Camera (WF/PC) images are analyzed in order to discover the most effective techniques for stellar photometry and to evaluate the accuracy and limitations of these techniques. The capabilities and operation of the WF/PC and the simulations employed in the study are described. The basic techniques of stellar photometry and methods to improve these techniques for the WF/PC are discussed. The correct parameters for star detection, aperture photometry, and point-spread function (PSF) fitting with the DAOPHOT software of Stetson (1987) are determined. Consideration is given to undersampling of the stellar images by the detector; variations in the PSF; and the crowding of the stellar images. It is noted that, with some changes DAOPHOT, is able to generate photometry almost to the level of photon statistics. 10 refs

  3. Southern Milky Way carbon stars - New candidates, JHK photometry, and radial velocities

    Blanco, V.M.; Cook, K.H.; Schechter, P.L.; Aaronson, M.

    1989-01-01

    Data are presented for low-latitude southern Milky Way carbon stars. Coordinates and cross identifications are given for carbon stars (67 of which are confirmed new discoveries) in seven fields deemed to be unusually transparent. JHK photometry is presented for 520 stars. Velocities are presented for 393 stars. Improved coordinates are presented for selected stars in Westerlund's catalog. Averaged photometry and velocities are presented for a sample of 336 stars. 26 refs

  4. K2 photometry and HERMES spectroscopy of the blue supergiant rho Leo

    Aerts, C.; Bowman, D. M.; Simon-Diaz, S.

    2018-01-01

    We present an 80-d long uninterrupted high-cadence K2 light curve of the B1Iab supergiant rho Leo (HD91316), deduced with the method of halo photometry. This light curve reveals a dominant frequency of f(rot) = 0.0373 d(-1) and its harmonics. This dominant frequency corresponds with a rotation...... period of 26.8 d and is subject to amplitude and phase modulation. The K2 photometry additionally reveals multiperiodic low-frequency variability (

  5. COLUROUTE : a mobile gonio-reflectometer to characterize the road surface photometry

    MUZET, Valérie; PAUMIER, Jean Luc; GUILLARD, Yannick

    2008-01-01

    Designing a lighting installation involves accounting for site-specific geometric parameters and photometric characteristics of both the light sources and the road surface. The standard tool for characterizing road surface photometry is the reduced luminance coefficient table (or R-table), as defined in the 70's by the CIE. However, recent studies have shown that these tables are no longer representative. In this context, measuring road photometry is necessary for optimizing a lighting ins...

  6. Precision photometry with difference imaging in the WTS

    Pinfield D.J.

    2013-04-01

    Full Text Available The Wide Field Camera Transit Survey is a pioneer program aimed to search for extra-solar planets in the near-infrared. The standard data reduction pipeline of the program uses aperture photometry to construct the light curves. We alternatively apply the difference imaging method for the most complete field in the survey and carry out a quantitative comparison between the photometric precision of both methods. We also report an implementation on the box-fitting detection algorithm, which performs a trapezoid-fit to the folded light curve. Subsequently we apply a set of selection criteria to the light curves to search for transit candidates, incorporating a parameter to characterize the shape of the transit. We carry out a detailed analysis of 11 candidates and provide a classification scheme to separate binary from planet candidates. Furthermore we report the detection of five faint extremely-short period eclipsing binary systems with periods shorter than 0.23 days and one candidate M-dwarf/M-dwarf eclipsing binary.

  7. BV CCD photometry of the old open cluster NGC 2243

    Bergbusch, P.A.; Vandenberg, D.A.; Infante, L.

    1991-01-01

    The photometry of NGC 2243 is presented, which reaches approximately 4 mag below the turnoff point calibrated independently of studies of the cluster. The color-magnitude diagram (CMD) and luminosity function (LF) are calibrated by utilizing stars from the lists of Landolt and Graham. A strong binary sequence is noted in the CMD which contributes approximately 30 percent of the stars, a gap is observed in the turnoff region, and a clump of HB stars is located. The CMD data are compared to those for the cluster 47 Tuc and are found to match well, although a slightly higher metal abundance accounts for the redder giant branch of the NGC 2243. The distance modulus and the cluster age are calculated, and the Fe/H = -0.47, O/Fe = +0.23 isochrones are the only isochrones that reproduce the location of the giant branch. A flat mass spectrum characterizes the LF, and a small gap is found where V is 16.1. Convective overshooting in the cores of moderate mass stars is theorized as the cause of the gap, and other models of the structure are shown to provide inadequate descriptions. 41 refs

  8. Deep CCD photometry in globular clusters. VII. M30

    Richer, H.B.; Fahlman, G.G.; Vandenberg, D.A.

    1988-01-01

    New UBV CCD photometry in a single field of the globular cluster M30 was obtained, and the data were used to obtain the color magnitude diagram (CMD) of the cluster, its luminosity function, and to derive fundamental cluster parameters. No blue stragglers were found, nor any evidence of a binary sequence in the data even though the field under study is only 21 core radii from the cluster center. The cluster reddening is observed to be 0.068 + or - 0.035, significantly higher than that adopted in most current papers on M30. An intercomparison of the CMDs of three very metal-poor clusters clearly shows that there is no evidence for any age difference between them. The age of M30 itself is found to be about 14 Gyr. The luminosity function of M30 is determined to be M(V) = 8. Comparison of this function with one found by Bolte (1987) at 65 core radii shows clear evidence of mass segregation in the low-mass stars. 44 references

  9. Deep CCD photometry in globular clusters III. M15

    Fahlman, G.G.; Richer, H.B.; Vandenberg, D.A.

    1985-01-01

    CCD photometry in U, B, and V is presented for a 5' x 3' field in the globular cluster M15. The location of the main sequence in the color-magnitude diagram is found here to be significantly bluer than previous studies have indicated. The luminosity function of the cluster is studied down to V = 22.8 (Mroughly-equal7.5) and shown to be consistent with a power-law mass function, n(M) = QM/sup -alpha/ with α = 2.5 +- 1.0, to the limit of our data. The field star population brighter than V = 21.5, is examined in some detail. There appears to be about 50% more stars belonging to the disk in the field as compared with the Bahcall-Soneira standard galaxy model. The reddening to the cluster is found to be E(B-V) = 0.11 +- 0.04 from nine bright field stars. A new value for the ultraviolet excess of the cluster main-sequence stars is obtained, delta(0.6) = 0.25 +- 0.02, and confirms the well-known fact that M15 is among the metal poorest of the globular clusters

  10. Infrared imaging and photometry of Comet Giacobini-Zinner

    Campins, H.

    1986-01-01

    Infrared images and photometry were obtained to determine the spatial distribution and physical characteristics (temperature, albedo, size distribution, total mass, etc.) of the grains in the coma of Comet GZ. A 10.8 m image of Comet GZ obtained on August 4 represents the first ground-based thermal-infrared image of a Comet. Among the most significant results are: (1) an estimate of the number of grains that the ICE spacecraft must have encountered, which led the plasma wave team to conclude that they could only detect impacts on the antennae and not on the whole body of the ICE spacecraft; (2) the discovery of a population of large grains (radius > 100 micrometer), not observed in most other comets, which formed a curved tail near the nucleus (within 80 arcsec or 34,000 km); and (3) the detection of structure in the spatial distribution in the coma of the particle albedo, which was tentatively attributed to the presence of very fluffy grains which are likely to have multiple internal scattering of incident sunlight. The albedo map of Comet GZ was obtained by combining the 10.8 micrometer image shown with a simultaneous image taken at 0.68 micrometer, a bandpass which isolates the scattered continuum

  11. Atomic absorption photometry of excess Zn in ZnO

    Lott, K.; Shinkarenko, S.; Tuern, L. [Department of Materials Science, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn (Estonia); Kirsanova, T.; Grebennik, A.; Vishnjakov, A. [Department of Physical Chemistry, D. Mendelejev University of Chemical Technology of Russia, Miusskaya Sq. 9, 125047 Moscow (Russian Federation)

    2005-02-01

    Zn excess in ZnO is built up automatically at high temperatures. Excess Zn in hydrothermally grown ZnO single crystals were investigated by the atomic absorption photometry (AAP) method. To determine the excess zinc in ZnO samples, the AAP of zinc vapour was used in the conditions of solid-vapour equilibrium. Zn AAP allowed to eliminate excess Zn connected differentially in ZnO samples. To fix Zn non-stoichiometry, all the ZnO samples tested were previously heat treated at temperature interval from 850 to 900 C and at fixed Zn vapour pressures from 0.1 to 0.9 of saturated zinc vapour pressure at given treatment temperature. The analysis of temperature dependence of zinc vapour pressure indicated that the impurity metals take active role in the determination of non-stoichiometric zinc. The impurities Mn, Fe, Co, Ni and Cu form oxides which will reduce during annealing in Zn vapor up to metals form. During AAP measurement in optical cuvette, these metals react with ZnO and give additional Zn vapor pressure. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Multicolor photometry of the nearby galaxy cluster A119

    Tian Jintao; Zhou Xu; Jiang Zhaoji; Ma Jun; Wu Zhenyu; Fan Zhou; Zhang Tianmeng; Zou Hu; Yuan Qirong; Wu Jianghua

    2012-01-01

    This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 (z = 0.0442) with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58' × 58', there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies (called sample I). Based on the spectral energy distributions of 1376 galaxies brighter than i BATC = 19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample (called sample II) of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynamically complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segregations is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario. (research papers)

  13. macula: Rotational modulations in the photometry of spotted stars

    Kipping, David M.

    2012-09-01

    Photometric rotational modulations due to starspots remain the most common and accessible way to study stellar activity. Modelling rotational modulations allows one to invert the observations into several basic parameters, such as the rotation period, spot coverage, stellar inclination and differential rotation rate. The most widely used analytic model for this inversion comes from Budding (1977) and Dorren (1987), who considered circular, grey starspots for a linearly limb darkened star. That model is extended to be more suitable in the analysis of high precision photometry such as that by Kepler. Macula, a Fortran 90 code, provides several improvements, such as non-linear limb darkening of the star and spot, a single-domain analytic function, partial derivatives for all input parameters, temporal partial derivatives, diluted light compensation, instrumental offset normalisations, differential rotation, starspot evolution and predictions of transit depth variations due to unocculted spots. The inclusion of non-linear limb darkening means macula has a maximum photometric error an order-of-magnitude less than that of Dorren (1987) for Sun-like stars observed in the Kepler-bandpass. The code executes three orders-of-magnitude faster than comparable numerical codes making it well-suited for inference problems.

  14. HUBBLE SPACE TELESCOPE PHOTOMETRY OF GLOBULAR CLUSTERS IN M81

    Nantais, Julie B.; Huchra, John P.; Zezas, Andreas; Gazeas, Kosmas; Strader, Jay

    2011-01-01

    We perform aperture photometry and profile fitting on 419 globular cluster (GC) candidates with m V ≤ 23 mag identified in Hubble Space Telescope/Advanced Camera for Surveys BVI imaging, and estimate the effective radii of the clusters. We identify 85 previously known spectroscopically confirmed clusters, and newly identify 136 objects as good cluster candidates within the 3σ color and size ranges defined by the spectroscopically confirmed clusters, yielding a total of 221 probable GCs. The luminosity function peak for the 221 probable GCs with estimated total dereddening applied is V ∼ (20.26 ± 0.13) mag, corresponding to a distance of ∼3.7 ± 0.3 Mpc. The blue and red GC candidates, and the metal-rich and metal-poor spectroscopically confirmed clusters, respectively, are similar in half-light radius. Red confirmed clusters are about 6% larger in median half-light radius than blue confirmed clusters, and red and blue good GC candidates are nearly identical in half-light radius. The total population of confirmed and 'good' candidates shows an increase in half-light radius as a function of galactocentric distance.

  15. Strategy for infrared photometry of comets with ISO

    Solc, M.; Vanysek, V.; Gruen, E.

    1994-07-01

    The launch of the ISO (Infrared Satellite Observatory) by the European Space Agency is scheduled for autumn 1995. Photometry and spectrophotometry observing programs of comets in the wavelength range 2.5-200 microns for the onboard spectrophotometer ISOPHOT is now under final preparation. Technical details for preparing propasals are given. Phenomena in comets to be studied are surface properties of bare cometary nuclei at large heliocentric distances, onset of coma activity, and coma dust and gas emission (in inner solar system). Dust production, dust/gas mass ratio, dust distribution in coma, and their temporal variability are important for understanding the physical processes on nuclei, and spectrophotometry in the range of 2.5-12 microns could provide us with data of the chemical composition of cometary dust. Several active comets expected for the 18-month lifetime of ISO in 1995-1997 were selected for the ISO Central Program according to their orbital and physical parameters: P/Schwassman-Wachmann 1, P/Encke, P/d'Arrest, P/Honda-Mrkos-Pajdusakova, P/Churyumov-Gerasimenko, P/Kopff, P/IRAS, P/Wirtanen, P/Wild 2, P/Grigg-Skjellerup, P/Schwassman-Wachmann 3, P/Machholz, and (2060) Chiron. Four of them match well various constraints put on the observations by the technical arrangement of the satellite and instrument. A simple four-parameter model (size, albedo, rotation, optical thickness)was developed to estimate the temperatures and thermal fluxes of both solid nuclei and dust coma.

  16. Near Continuous Photometry with the Whole Earth Telescope (WET

    Solheim J. E.

    2003-12-01

    Full Text Available The Whole Earth Telescope (WET saw first light in 1988. It was invented by scientists from the Astronomy Department, University of Texas at Austin. The idea was to generate a world-wide network of cooperating astronomical observatories to obtain uninterrupted time-series measurements of some variable stars. The technological goal was to resolve the multi-periodic oscillations in these objects into their individual components; the scientific goal was to construct accurate theoretical models of the target objects, constrained by their observed behavior, from which fundamental astrophysical parameters could be derived. This approach has been extremely successful, and has placed stellar seismology at the forefront of stellar astrophysics. The network is run as a single astronomical instrument with many operators, and the collaboration includes scientists from all continents on our planet, taking part in the observations, data reduction, analysis and theoretical interpretation. The expertise of Lithuanian astronomers in photometry, and their access to the observing station Mt. Maidanak in Uzbekistan, has been important for the success of the network.

  17. Photographic surface photometry of NGC 2855 and NGC 6771 galaxies

    Schroeder, M. de F.S.

    1984-01-01

    Photographic surface photometry in the BV system was carried out two Southern SO's galaxies, NGC 2855 and NGC 6771. B and V isophote maps were obtained as well as geometric and integrated parameters as position angles, inclination, diameters, magnitudes and integrated colors. Each luminosity profile was decomposed into bulge and disk contributions, each component being fitted to convenient laws. For NGC 2855 de Vaucouleurs law described well the bulge whereas the disk showed an exponential distribution. For NGC 6771 the barred nuclear bulge as well as the disk was best fitted by exponential laws. Additional luminosity components due to an inner fragmented ring were identified in NGC 2855 and due to both a quite prominent lens and well defined ring in NGC 6771. In this galaxy the minor axis, oriented almost edge-on, present clues of another luminosity component besides the bulge and the thin disk. For both galaxies the disk central surface brightness was found to be fainter than the standard value observed by Freeman. The fitting parameters were used to determine the bulge-to-disk luminosity ratios as well as their contribution to total luminosity. The domination by the bulge light over the disk light was clear in both galaxies. From the B and V luminosity profile the color gradients were estimated. For both objects the local color indices decreased from inner to outer regions, this effect being relatively smooth in NGC 2855 and more prominent in NGC 6771 [pt

  18. Integrated photometry of globular star clusters in the Vilnius system

    Zdanavichyus, K.V.

    1983-01-01

    Integrated colour indices in the Vilnius photometric system and newly determined colour excesses Esub(B-V) for 39 globular clusters are presented. It is shown that the coincidence of integrated spectral types are not a sufficient criterion for the identity of intrinsic colour indices of globular clusters. Relation of integrated colour indices with the slope of the giant branch S and with the horizontal branch morphological type D is investigated. Integrated colour indices of clusters with a blue horizontal branch show no correlation with either D or S. The increase of colour indices of the clusters of types D >= 4 correlates with the distribution of stars along the horizontal branch. Integrated photometry of globular star clusters in the Vilnius multicoloured photometric system permits to determine their colour excesses from some Q diagrams and normal colour index. Integral normal colour indexes and Q parameters for I globular star clusters of the Mironov group display small changes as compared to clusters of group 2. Colour indexes among star clusters having only red horizontal branches (D=7) change most considerably

  19. Linear surface photoelectric effect of gold in intense laser field as a possible high-current electron source

    Farkas, G.; Horvath, Z.G.; Toth, C.; Fotakis, C.; Hontzopoulos, E.

    1987-01-01

    Investigations were conducted on radiation-induced electron emission processes on a gold target surface with a high-intensity (2 MW/cm 2 ) KrF laser (λ = 248 nm). The single photon surface photoelectric emission obtained can be used for high-current density electron sources. The measured polarization dependence of electron current shows the dominance of the surface-type effect over that of the volume type, thereby making it possible to optimize the short, high-density electron current creation conditions. The advantage of the grazing light incidence and the multiphoton photoeffect giving rise to a 500 A/cm 2 electron current has been demonstrated

  20. The photoelectric effect and study of the diffraction of light: Two new experiments in UNILabs virtual and remote laboratories network

    Sánchez, Juan Pedro; Carreras, Carmen; Yuste, Manuel; Dormido, Sebastián; Sáenz, Jacobo; De la Torre, Luis; Rubén, Heradio

    2015-01-01

    This work describes two experiments: 'study of the diffraction of light: Fraunhofer approximation' and 'the photoelectric effect'. Both of them count with a virtual, simulated, version of the experiment as well as with a real one which can be operated remotely. The two previous virtual and remote labs (built using Easy Java(script) Simulations) are integrated in UNILabs, a network of online interactive laboratories based on the free Learning Management System Moodle. In this web environment, students can find not only the virtual and remote labs but also manuals with related theory, the user interface description for each application, and so on.

  1. Narrow-Band Processing and Fusion Approach for Explosive Hazard Detection in FLGPR

    2011-01-01

    Keller, K. C. Ho, Tuan T. Ton, David C. Wong, Mehrdad Soumekh University of Missouri - Columbia Office of Sponsored Programs The Curators of the...Timothy C. Havens* a , James M. Keller a , K.C. Ho a , Tuan T. Ton b , David C. Wong b , and Mehrdad Soumekh c a Dept. of Electrical and Computer...ARO. REFERENCES [1] Cremer , F., Schavemaker, J.G., de Jong, W., and Schutte, K., "Comparison of vehicle-mounted forward-looking polarimetric

  2. Assessing the importance of frustration in a narrow-band strongly correlated electronic chain

    Lal, Siddhartha; Laad, Mukul S.

    2007-08-01

    We study a one-dimensional extended Hubbard model with longer-range Coulomb interactions at quarter-filling in the strong coupling limit. In this limit, we find the one dimensional transverse field Ising model (TFIM) to be the effective Hamiltonian governing the dynamics of the charge degrees of freedom. We find two different charge-ordered (CO) ground states as the strength of the longer range interactions is varied. At lower energies, these CO states drive two different spin-ordered ground states. A variety of response functions computed here bear a remarkable resemblance to recent experimental observations for organic TMTSF systems, and so we propose that these systems are proximate to a QCP associated with T = 0 charge order. (author)

  3. Photo-Induced Electron Spin Polarization in a Narrow Band Gap Semiconductor Nanostructure

    Peter, A. John; Lee, Chang Woo

    2012-01-01

    Photo-induced spin dependent electron transmission through a narrow gap InSb/InGa x Sb 1−x semiconductor symmetric well is theoretically studied using transfer matrix formulism. The transparency of electron transmission is calculated as a function of electron energy for different concentrations of gallium. Enhanced spin-polarized photon assisted resonant tunnelling in the heterostructure due to Dresselhaus and Rashba spin-orbit coupling induced splitting of the resonant level and compressed spin-polarization are observed. Our results show that Dresselhaus spin-orbit coupling is dominant for the photon effect and the computed polarization efficiency increases with the photon effect and the gallium concentration

  4. Interaction Structures for Narrow-Band Millimeter-Wave Communications TWTs.

    1981-04-01

    comb would be cut from a single piece of copper, probably by a reliable but inexpensive technique such as electroerosion or "chemical milling". All...dimensional. These features would facilitate fabrication by chemical (photo-lithographic) or laser milling as well as by electroerosion with traveling...c, d) has also been implemented since this design should be more robust as well as compatible with electroerosion cutting using a traveling-wire

  5. Fully Modified Narrow-Band Least Squares Estimation of Weak Fractional Cointegration

    Nielsen, Morten Ørregaard; Frederiksen, Per

    regressors and errors at the zero frequency. We show that in the absence of this condition, the NBLS estimator is asymptotically biased, and also that the bias can be consistently estimated. Consequently, we introduce a fully modi…ed NBLS estimator which eliminates the bias, and indeed enjoys a faster rate...

  6. An alternative method for calibration of narrow band radiometer using a radiative transfer model

    Salvador, J; Wolfram, E; D' Elia, R [Centro de Investigaciones en Laseres y Aplicaciones, CEILAP (CITEFA-CONICET), Juan B. de La Salle 4397 (B1603ALO), Villa Martelli, Buenos Aires (Argentina); Zamorano, F; Casiccia, C [Laboratorio de Ozono y Radiacion UV, Universidad de Magallanes, Punta Arenas (Chile) (Chile); Rosales, A [Universidad Nacional de la Patagonia San Juan Bosco, UNPSJB, Facultad de Ingenieria, Trelew (Argentina) (Argentina); Quel, E, E-mail: jsalvador@citefa.gov.ar [Universidad Nacional de la Patagonia Austral, Unidad Academica Rio Gallegos Avda. Lisandro de la Torre 1070 ciudad de Rio Gallegos-Sta Cruz (Argentina) (Argentina)

    2011-01-01

    The continual monitoring of solar UV radiation is one of the major objectives proposed by many atmosphere research groups. The purpose of this task is to determine the status and degree of progress over time of the anthropogenic composition perturbation of the atmosphere. Such changes affect the intensity of the UV solar radiation transmitted through the atmosphere that then interacts with living organisms and all materials, causing serious consequences in terms of human health and durability of materials that interact with this radiation. One of the many challenges that need to be faced to perform these measurements correctly is the maintenance of periodic calibrations of these instruments. Otherwise, damage caused by the UV radiation received will render any one calibration useless after the passage of some time. This requirement makes the usage of these instruments unattractive, and the lack of frequent calibration may lead to the loss of large amounts of acquired data. Motivated by this need to maintain calibration or, at least, know the degree of stability of instrumental behavior, we have developed a calibration methodology that uses the potential of radiative transfer models to model solar radiation with 5% accuracy or better relative to actual conditions. Voltage values in each radiometer channel involved in the calibration process are carefully selected from clear sky data. Thus, tables are constructed with voltage values corresponding to various atmospheric conditions for a given solar zenith angle. Then we model with a radiative transfer model using the same conditions as for the measurements to assemble sets of values for each zenith angle. The ratio of each group (measured and modeled) allows us to calculate the calibration coefficient value as a function of zenith angle as well as the cosine response presented by the radiometer. The calibration results obtained by this method were compared with those obtained with a Brewer MKIII SN 80 located in the city of Punta Arenas, Chile using the sun as a source. These results show us that the proposed method is a viable alternative for developing countries that use instrumentation of this type and find it difficult to apply calibration programs on a regular basis.

  7. Tunable Narrow Band Gap Absorbers For Ultra High Efficiency Solar Cells

    Bedair, Salah M. [North Carolina State Univ., Raleigh, NC (United States); Hauser, John R. [North Carolina State Univ., Raleigh, NC (United States); Elmasry, Nadia [North Carolina State Univ., Raleigh, NC (United States); Colter, Peter C. [North Carolina State Univ., Raleigh, NC (United States); Bradshaw, G. [North Carolina State Univ., Raleigh, NC (United States); Carlin, C. Z. [North Carolina State Univ., Raleigh, NC (United States); Samberg, J. [North Carolina State Univ., Raleigh, NC (United States); Edmonson, Kenneth [Spectrolab, Inc., Sylmar, CA (United States)

    2012-07-31

    We report on a joint research program between NCSU and Spectrolab to develop an upright multijunction solar cell structure with a potential efficiency exceeding the current record of 41.6% reported by Spectrolab. The record efficiency Ge/GaAs/InGaP triple junction cell structure is handicapped by the fact that the current generated by the Ge cell is much higher than that of both the middle and top cells. We carried out a modification of the record cell structure that will keep the lattice matched condition and allow better matching of the current generated by each cell. We used the concept of strain balanced strained layer superlattices (SLS), inserted in the i-layer, to reduce the bandgap of the middle cell without violating the desirable lattice matched condition. For the middle GaAs cell, we have demonstrated an n-GaAs/i-(InGaAs/GaAsP)/p-GaAs structure, where the InxGa1-xAs/GaAs1-yPy SLS is grown lattice matched to GaAs and with reduced bandgap from 1.43 eV to 1.2 eV, depending upon the values of x and y.

  8. Modeling auditory processing of amplitude modulation I. Detection and masking with narrow-band carriers

    Dau, T.; Kollmeier, B.; Kohlrausch, A.G.

    1997-01-01

    This paper presents a quantitative model for describing data from modulation-detection and modulation-masking experiments, which extends the model of the "effective" signal processing of the auditory system described in Dau et al. [J. Acoust. Soc. Am. 99, 3615–3622 (1996)]. The new element in the

  9. Narrow band imaging is a new technique in visualization of recurrent respiratory papillomatosis

    Tjon Pian Gi, Robin E A; Halmos, Gyorgy B; van Hemel, Bettien M; van den Heuvel, Edwin R; van der Laan, Bernard F A M; Plaat, Boudewijn E C; Dikkers, Frederik G

    Objectives/Hypothesis: Recurrent respiratory papillomatosis (RRP) is a rare, benign, wart-like disease for which no curative treatment exists. The goal of treatment is total surgical removal of the epithelial lesions to keep the airway open and the voice sufficient. Therefore, it is essential to

  10. Hemispherical-field-of-view, nonimaging narrow-band spectral filter

    Miles, R. B.; Webb, S. G.; Griffith, E. L.

    1981-01-01

    Two compound parabolic concentrators are used to create a 180-deg-field-of-view spectral filter. The collection optics are reflective and are designed to collimate the light through a multilayer interference filter and then to refocus it onto an optical detector. Assuming unit reflectance and no loss through the optical filter, this device operates at the thermodynamic collection limit.

  11. Calculation of electrostatic multipoles of electron localized in narrow-band InSb spherical nanolayer

    Amirkhanyan, S.M.; Kazaryan, E.M.; Sarkisyan, H.A.

    2015-01-01

    Behavior of electron in narrow-gap spherical nanolayer of InSb is considered. Dispersion law of electron is described within the double-gap Kane model, when arises a necessity for considering of Klein-Gordon equation for description of behavior of electrons and light holes. Dipole and quadrupole momentums of electron in specified systems are defined on the base of the obtained expressions. It is shown, that average value of dipole momentum equals to zero and that for definition of average value of tensor of quadrupole momentum it is enough to calculate the average value of diagonal z-component of this tensor. Electrostatic potentials and tensions of fields created by electron located in different quantum states are defined

  12. Erbium-doped twin-core fibre narrow-band filter for fibre lasers

    Peterka, Pavel; Kaňka, Jiří

    2001-01-01

    Roč. 33, 4/5 (2001), s. 571-581 ISSN 0306-8919. [Optical Waveguide Theory and Numerical Modelling /8./. Prague, 26.05.2000-27.05.2000] R&D Projects: GA ČR GA102/99/M057; GA ČR GA102/99/0393; GA AV ČR IAC2067902 Grant - others:EU COST(XE) OC 265.10 Institutional research plan: CEZ:AV0Z2067918 Keywords : optical fibre lasers * optical fibre filters * optical fibre couplers Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.706, year: 2001 http://www.ufe.cz/~peterka/opera/OQE_Peterka01_fulltext.pdf

  13. Design of an S band narrow-band bandpass BAW filter

    Gao, Yang; Zhao, Kun-li; Han, Chao

    2017-11-01

    An S band narrowband bandpass filter BAW with center frequency 2.460 GHz, bandwidth 41MHz, band insertion loss - 1.154 dB, the passband ripple 0.9 dB, the out of band rejection about -42.5dB@2.385 GHz; -45.5dB@2.506 GHz was designed for potential UAV measurement and control applications. According to the design specifications, the design is as follows: each FBAR's stack was designed in BAW filter by using Mason model. Each FBAR's shape was designed with the method of apodization electrode. The layout of BAW filter was designed. The acoustic-electromagnetic cosimulation model was built to validate the performance of the designed BAW filter. The presented design procedure is a common one, and there are two characteristics: 1) an A and EM co-simulation method is used for the final BAW filter performance validation in the design stage, thus ensures over-optimistic designs by the bare 1D Mason model are found and rejected in time; 2) An in-house developed auto-layout method is used to get compact BAW filter layout, which simplifies iterative error-and-try work here and output necessary in-plane geometry information to the A and EM cosimulation model.

  14. Stochastic algorithm for channel optimized vector quantization: application to robust narrow-band speech coding

    Bouzid, M.; Benkherouf, H.; Benzadi, K.

    2011-01-01

    In this paper, we propose a stochastic joint source-channel scheme developed for efficient and robust encoding of spectral speech LSF parameters. The encoding system, named LSF-SSCOVQ-RC, is an LSF encoding scheme based on a reduced complexity stochastic split vector quantizer optimized for noisy channel. For transmissions over noisy channel, we will show first that our LSF-SSCOVQ-RC encoder outperforms the conventional LSF encoder designed by the split vector quantizer. After that, we applied the LSF-SSCOVQ-RC encoder (with weighted distance) for the robust encoding of LSF parameters of the 2.4 Kbits/s MELP speech coder operating over a noisy/noiseless channel. The simulation results will show that the proposed LSF encoder, incorporated in the MELP, ensure better performances than the original MELP MSVQ of 25 bits/frame; especially when the transmission channel is highly disturbed. Indeed, we will show that the LSF-SSCOVQ-RC yields significant improvement to the LSFs encoding performances by ensuring reliable transmissions over noisy channel.

  15. The split symbol moments SNR estimator in narrow-band channels

    Shah, Biren; Hinedi, Sami

    1990-01-01

    The split symbol moments estimator is an algorithm that is designed to estimate symbol SNR in the presence of additive white Gaussian noise. The performance of the algorithm in band-limited channels is examined, and the effects of the resulting intersymbol interference are quantified. All results obtained are in closed form and can be easily evaluated numerically for performance-prediction purposes. The results are also validated through digital simulations.

  16. Narrow band flame emission from dieseline and diesel spray combustion in a constant volume combustion chamber

    Wu, Zengyang; Jing, Wei; Zhang, Weibo; Roberts, William L.; Fang, Tiegang

    2016-01-01

    emissions were studied. Ambient oxygen concentration was varied from 12% to 21% and three ambient temperatures were selected: 800 K, 1000 K and 1200 K. An intensified CCD camera coupled with bandpass filters was employed to capture the quasi-steady state

  17. Antarctic krill under sea ice: elevated abundance in a narrow band just south of ice edge.

    Brierley, Andrew S; Fernandes, Paul G; Brandon, Mark A; Armstrong, Frederick; Millard, Nicholas W; McPhail, Steven D; Stevenson, Peter; Pebody, Miles; Perrett, James; Squires, Mark; Bone, Douglas G; Griffiths, Gwyn

    2002-03-08

    We surveyed Antarctic krill (Euphausia superba) under sea ice using the autonomous underwater vehicle Autosub-2. Krill were concentrated within a band under ice between 1 and 13 kilometers south of the ice edge. Within this band, krill densities were fivefold greater than that of open water. The under-ice environment has long been considered an important habitat for krill, but sampling difficulties have previously prevented direct observations under ice over the scale necessary for robust krill density estimation. Autosub-2 enabled us to make continuous high-resolution measurements of krill density under ice reaching 27 kilometers beyond the ice edge.

  18. Narrow-band light emission from a single carbon nanotube p-n diode

    Kinoshita, Megumi; Mueller, Thomas; Steiner, Mathias; Perebeinos, Vasili; Bol, Ageeth; Farmer, Damon; Avouris, Phaedon

    2010-03-01

    We present the first observation of electroluminescence from electrostatically-generated carbon nanotube (CNT) p-n junctions[1]. While CNT optoelectronics has made much progress in recent years, observations of emission from electrically excited CNT devices have been limited to the high-bias regime and with low efficiency. Furthermore, the resulting broad linewidths are broad, making it difficult to investigate electronic levels and carrier dynamics. We find that p-n junctions allow for better carrier control at lower power inputs, resulting in emission with near-zero threshold, low self-heating and efficiency two to three orders of magnitude greater compared to previous device configurations. This yields higher signal-to-noise ratio and narrower linewidths (down to ˜35 meV) that allows us to identify localized excitonic transitions that have previously been observed only in photoluminescent studies. [1] T. Mueller, M. Kinoshita, M. Steiner, V. Perebeinos, A. Bol, D. Farmer, and Ph. Avouris, Nature Nanotech., web publication, November 15 2009.

  19. Characterization of VHF radar observations associated with equatorial Spread F by narrow-band optical measurements

    R. Sekar

    2004-09-01

    Full Text Available The VHF radars have been extensively used to investigate the structures and dynamics of equatorial Spread F (ESF irregularities. However, unambiguous identification of the nature of the structures in terms of plasma depletion or enhancement requires another technique, as the return echo measured by VHF radar is proportional to the square of the electron density fluctuations. In order to address this issue, co-ordinated radar backscatter and thermospheric airglow intensity measurements were carried out during March 2003 from the MST radar site at Gadanki. Temporal variations of 630.0-nm and 777.4-nm emission intensities reveal small-scale ("micro" and large-scale ("macro" variations during the period of observation. The micro variations are absent on non-ESF nights while the macro variations are present on both ESF and non-ESF nights. In addition to the well-known anti-correlation between the base height of the F-region and the nocturnal variation of thermospheric airglow intensities, the variation of the base height of the F-layer, on occasion, is found to manifest as a bottomside wave-like structure, as seen by VHF radar on an ESF night. The micro variations in the airglow intensities are associated with large-scale irregular plasma structures and found to be in correspondence with the "plume" structures obtained by VHF radar. In addition to the commonly observed depletions with upward movement, the observation unequivocally reveals the presence of plasma enhancements which move downwards. The observation of enhancement in 777.4-nm airglow intensity, which is characterized as plasma enhancement, provides an experimental verification of the earlier prediction based on numerical modeling studies.

  20. A novel facility for ageing materials with narrow-band ultraviolet radiation exposure

    Kaerhae, Petri; Ruokolainen, Kimmo; Heikkilae, Anu; Kaunismaa, Merja

    2011-01-01

    A facility for exploring wavelength dependencies in ultraviolet (UV) radiation induced degradation in materials has been designed and constructed. The device is essentially a spectrograph separating light from a lamp to spectrally resolved UV radiation. It is based on a 1 kW xenon lamp and a flat-field concave holographic grating 10 cm in diameter. Radiation at the wavelength range 250-500 nm is dispersed onto the sample plane of 1.5 cm in height and 21 cm in width. The optical performance of the device has been characterized by radiometric measurements. Using the facility, test samples prepared of regular newspaper have been irradiated from 1 to 8 h. Color changes on the different locations of the aged samples have been quantified by color measurements. Yellowness indices computed from the color measurements demonstrate the capability of the facility in revealing wavelength dependencies of the material property changes in reasonable time frames.

  1. Frequency-bin entanglement of ultra-narrow band non-degenerate photon pairs

    Rieländer, Daniel; Lenhard, Andreas; Jime`nez Farìas, Osvaldo; Máttar, Alejandro; Cavalcanti, Daniel; Mazzera, Margherita; Acín, Antonio; de Riedmatten, Hugues

    2018-01-01

    We demonstrate frequency-bin entanglement between ultra-narrowband photons generated by cavity enhanced spontaneous parametric down conversion. Our source generates photon pairs in widely non-degenerate discrete frequency modes, with one photon resonant with a quantum memory material based on praseodymium doped crystals and the other photon at telecom wavelengths. Correlations between the frequency modes are analyzed using phase modulators and narrowband filters before detection. We show high-visibility two photon interference between the frequency modes, allowing us to infer a coherent superposition of the modes. We develop a model describing the state that we create and use it to estimate optimal measurements to achieve a violation of the Clauser-Horne (CH) Bell inequality under realistic assumptions. With these settings we perform a Bell test and show a significant violation of the CH inequality, thus proving the entanglement of the photons. Finally we demonstrate the compatibility with a quantum memory material by using a spectral hole in the praseodymium (Pr) doped crystal as spectral filter for measuring high-visibility two-photon interference. This demonstrates the feasibility of combining frequency-bin entangled photon pairs with Pr-based solid state quantum memories.

  2. Characterization of 3 to 5 Micron Thermal Imagers and Analysis of Narrow Band Images

    Quek, Yew S

    2004-01-01

    ...) and the Minimum Resolvable Temperature (MRT). An available thermal imager, the Cincinnati Electronics IRRIS-256LN, and a newly purchased thermal imager, the Indigo Systems Merlin InSb Laboratory Camera, were investigated and compared...

  3. Searching for illicit materials using nuclear resonance fluorescence stimulated by narrow-band photon sources

    Johnson, M.S., E-mail: johnson329@llnl.gov [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); San Jose State University, San Jose, CA 95192 (United States); Hagmann, C.A.; Hall, J.M.; McNabb, D.P. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Kelley, J.H.; Huibregtse, C. [North Carolina State University, Raleigh, NC 27695 (United States); Kwan, E.; Rusev, G.; Tonchev, A.P. [Duke University, Durham, NC 27708 (United States)

    2012-08-15

    We report the results of an experimental study of the sensitivity of two distinct classes of systems that exploit nuclear resonance fluorescence (NRF) to search for illicit materials in containers. One class of systems is based on the direct detection of NRF photons emitted from isotopes of interest. The other class infers the presence of a particular isotope by observing the preferential attenuation of resonant photons in the incident beam. We developed a detailed analytical model for both approaches. We performed experiments to test the model using depleted uranium as a surrogate for illicit material and used tungsten as a random choice for shielding. We performed the experiments at Duke University's High Intensity Gamma Source (HIGS). Using the methodology we detail in this paper one can use this model to estimate the performance of potential inspection systems in certifying containers as free of illicit materials and for detecting the presence of those same materials.

  4. Tunable narrow band difference frequency THz wave generation in DAST via dual seed PPLN OPG.

    Dolasinski, Brian; Powers, Peter E; Haus, Joseph W; Cooney, Adam

    2015-02-09

    We report a widely tunable narrowband terahertz (THz) source via difference frequency generation (DFG). A narrowband THz source uses the output of dual seeded periodically poled lithium niobate (PPLN) optical parametric generators (OPG) combined in the nonlinear crystal 4-dimthylamino-N-methyl-4-stilbazolium-tosylate (DAST). We demonstrate a seamlessly tunable THZ output that tunes from 1.5 THz to 27 THz with a minimum bandwidth of 3.1 GHz. The effects of dispersive phase matching, two-photon absorption, and polarization were examined and compared to a power emission model that consisted of the current accepted parameters of DAST.

  5. Correlation and Collective Modes in Narrow Band Materials: NiO and FeO.

    1981-02-01

    reduced and could have been Cu 20. Madey and Hanni have made an estimate of the density of surface bosons nceded to provide the observed shielding of the...and Hanni indicates that acsuming an ideal Bose gas composed of coupled free electrons may overestimate the screening. The electric field in the...the surface state is then T m a e exp m(3.18 2e2dm J e( It is Eq. (3.18) that Madey and Hanni use to fit the experimental data of -6011 -2 Witteborn

  6. Two Herbig-Haro objects discovered by narrow-band CCD imagery

    Ogura, Katsuo

    1990-01-01

    Two new Herbig-Haro objects, HH 132 and HH 133, have been discovered by CCD imagery behind interference filters on and just off the forbidden S II lines in the red. They are located in Puppis R2 and in Vela R2. Possible locations of their exciting sources are discussed. 12 refs

  7. Ultra-narrow band diode lasers with arbitrary pulse shape modulation (Conference Presentation)

    Ryasnyanskiy, Aleksandr I.; Smirnov, Vadim; Mokhun, Oleksiy; Glebov, Alexei L.; Glebov, Leon B.

    2017-03-01

    Wideband emission spectra of laser diode bars (several nanometers) can be largely narrowed by the usage of thick volume Bragg gratings (VBGs) recorded in photo-thermo-refractive glass. Such narrowband systems, with GHz-wide emission spectra, found broad applications for Diode Pumped Alkali vapor Lasers, optically pumped rare gas metastable lasers, Spin Exchange Optical Pumping, atom cooling, etc. Although the majority of current applications of narrow line diode lasers require CW operation, there are a variety of fields where operation in a different pulse mode regime is necessary. Commercial electric pulse generators can provide arbitrary current pulse profiles (sinusoidal, rectangular, triangular and their combinations). The pulse duration and repetition rate however, have an influence on the laser diode temperature, and therefore, the emitting wavelength. Thus, a detailed analysis is needed to understand the correspondence between the optical pulse profiles from a diode laser and the current pulse profiles; how the pulse profile and duty cycle affects the laser performance (e.g. the wavelength stability, signal to noise ratio, power stability etc.). We present the results of detailed studies of the narrowband laser diode performance operating in different temporal regimes with arbitrary pulse profiles. The developed narrowband (16 pm) tunable laser systems at 795 nm are capable of operating in different pulse regimes while keeping the linewidth, wavelength, and signal-to-noise ratio (>20 dB) similar to the corresponding CW modules.

  8. Preparation and photoelectric properties of p-CaFe2O4/n-WO3 composites

    Wan, Ruiqin; Jia, Caihong; Zhang, Weifeng

    2012-01-01

    Highlights: ► Surface photovoltage spectroscopy investigation on p-CaFe 2 O 4 /n-WO 3 composites. ► The photovoltaic response is enhanced in p-CaFe 2 O 4 /n-WO 3 composites. ► The multielectron process and high rate of carrier migration in WO 3 . - Abstract: Composites of p-CaFe 2 O 4 /n-WO 3 are prepared via a sol–gel technique. Their structures and optical properties are characterized with X-ray diffraction, scanning electron microscopy and UV–vis absorption spectroscopy. The photoelectric characteristics are investigated by surface photovoltage spectroscopy combined with electric field induced surface photovoltage spectroscopy. The results indicate that CaFe 2 O 4 can well form a p–n type composite with WO 3 , and the intensity and spectral region of surface photovoltaic response for the composites are strongly dependent on the molar ratio of two components. The enhancement in photoelectric properties and the effective separation of photogenerated carriers could be attributed to the energy level matching between the two components, multielectron process and the high migration rate in WO 3 .

  9. The RSA survey of dwarf galaxies, 1: Optical photometry

    Vader, J. Patricia; Chaboyer, Brian

    1994-01-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are

  10. CHARACTERIZATION OF SLOAN DIGITAL SKY SURVEY STELLAR PHOTOMETRY

    Fukugita, Masataka; Yasuda, Naoki; Doi, Mamoru; Gunn, James E.; York, Donald G.

    2011-01-01

    We study the photometric properties of stars in the data archive of the Sloan Digital Sky Survey (SDSS), the prime aim being to understand the photometric calibration over the entire data set. It is confirmed that the photometric calibration of point sources is accurately on the system defined by the SDSS standard stars. We have also confirmed that the photometric synthesis of the SDSS spectrophotometric data gives broadband fluxes that agree with the photometry with errors of no more than 0.04 mag and little systematic tilt with wavelength. This verifies that the response functions of the 2.5 m telescope system are well characterized. We locate stars in the SDSS photometric system, so that stars can roughly be classified into spectral classes from the color information. We show how metallicity and surface gravity affect colors, and that stars contained in the SDSS general catalog, plotted in color space, show a distribution that matches well with what is anticipated from the variations of metallicity and surface gravity. The color-color plots are perfectly consistent among the three samples-stars in the SDSS general catalog, SDSS standard stars, and spectrophotometric stars of Gunn and Stryker-especially when some considerations are taken into account of the differences (primarily metallicity) of the samples. We show that the g - r-inverse temperature relation is tight and can be used as a good estimator of the effective temperature of stars over a fairly wide range of effective temperatures. We also confirm that the colors of G2V stars in the SDSS photometric system match well with the Sun.

  11. High-precision ground-based photometry of exoplanets

    de Mooij Ernst J.W.

    2013-04-01

    Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana. The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level, this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

  12. Precision Photometry to Study the Nature of Dark Energy

    Lorenzon, Wolfgang; Schubnell, Michael

    2011-01-01

    Over the past decade scientists have collected convincing evidence that the expansion of the universe is accelerating, leading to the conclusion that the content of our universe is dominated by a mysterious 'dark energy'. The fact that present theory cannot account for the dark energy has made the determination of the nature of dark energy central to the field of high energy physics. It is expected that nothing short of a revolution in our understanding of the fundamental laws of physics is required to fully understand the accelerating universe. Discovering the nature of dark energy is a very difficult task, and requires experiments that employ a combination of different observational techniques, such as type-Ia supernovae, gravitational weak lensing surveys, galaxy and galaxy cluster surveys, and baryon acoustic oscillations. A critical component of any approach to understanding the nature of dark energy is precision photometry. This report addresses just that. Most dark energy missions will require photometric calibration over a wide range of intensities using standardized stars and internal reference sources. All of the techniques proposed for these missions rely on a complete understanding of the linearity of the detectors. The technical report focuses on the investigation and characterization of 'reciprocity failure', a newly discovered count-rate dependent nonlinearity in the NICMOS cameras on the Hubble Space Telescope. In order to quantify reciprocity failure for modern astronomical detectors, we built a dedicated reciprocity test setup that produced a known amount of light on a detector, and to measured its response as a function of light intensity and wavelength.

  13. X-ray attenuation coefficients and photoelectric cross sections of Cu, Fe and Sn for the energy range 3-29 KeV

    Wang Dachun; Yang Hua; Luo Pingan; Ding Xunliang; Wang Xinfu; Zhou Hongyu; Shen Xinyin; Zhu Guanghua

    1991-08-01

    The document contains the following two papers: X-ray attenuation coefficient and photoelectric cross sections of Sn for the Energy Range 3.3 KeV to 29.1 KeV - by Wang Dachun, Yang Hua and Luo Pingan. X-ray attenuation coefficients and photoelectric cross sections of Cu and Fe for the range 3 KeV to 29 KeV - by Wang Dachun, Ding Xunliang, Wang Xinfu, Yang Hua, Zhou Hongyu, Shen Xinyin and Zhu Guanghua. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  14. DustPedia: Multiwavelength photometry and imagery of 875 nearby galaxies in 42 ultraviolet-microwave bands

    Clark, C. J. R.; Verstocken, S.; Bianchi, S.; Fritz, J.; Viaene, S.; Smith, M. W. L.; Baes, M.; Casasola, V.; Cassara, L. P.; Davies, J. I.; De Looze, I.; De Vis, P.; Evans, R.; Galametz, M.; Jones, A. P.; Lianou, S.; Madden, S.; Mosenkov, A. V.; Xilouris, M.

    2018-01-01

    Aims: The DustPedia project is capitalising on the legacy of the Herschel Space Observatory, using cutting-edge modelling techniques to study dust in the 875 DustPedia galaxies - representing the vast majority of extended galaxies within 3000 km s-1 that were observed by Herschel. This work requires a database of multiwavelength imagery and photometry that greatly exceeds the scope (in terms of wavelength coverage and number of galaxies) of any previous local-Universe survey. Methods: We constructed a database containing our own custom Herschel reductions, along with standardised archival observations from GALEX, SDSS, DSS, 2MASS, WISE, Spitzer, and Planck. Using these data, we performed consistent aperture-matched photometry, which we combined with external supplementary photometry from IRAS and Planck. Results: We present our multiwavelength imagery and photometry across 42 UV-microwave bands for the 875 DustPedia galaxies. Our aperture-matched photometry, combined with the external supplementary photometry, represents a total of 21 857 photometric measurements. A typical DustPedia galaxy has multiwavelength photometry spanning 25 bands. We also present the Comprehensive & Adaptable Aperture Photometry Routine (CAAPR), the pipeline we developed to carry out our aperture-matched photometry. CAAPR is designed to produce consistent photometry for the enormous range of galaxy and observation types in our data. In particular, CAAPR is able to determine robust cross-compatible uncertainties, thanks to a novel method for reliably extrapolating the aperture noise for observations that cover a very limited amount of background. Our rich database of imagery and photometry is being made available to the community. Photometry data tables are only available 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/609/A37

  15. [Objective non-contact method of study of the color of the human skin integument by use of a photoelectric colorimeter].

    Gruzdeva, N I; Zherebtsov, L D; Vasilevskiĭ, V K; Vremzen, S A

    1975-04-01

    The authors describe a method of determination of the colour of the skin in man based on the use of contactless photoelectric colorimeter made especially for this purpose. The mean normal values of the indices of the skin colour of the anterior and the posterior surface of the arm in 45 men and 35 women of the Europeoid race under normal conditions are presented.

  16. Measured energy dependence of L-shell photoelectric cross sections of lead in the energy region 17-50 keV

    Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1980-08-28

    The energy dependence of L-shell photoelectric cross sections for lead in the energy region 17-50 keV has been investigated. The method utilises external conversion x-rays as the source of photons and it yields relative rather than absolute cross sections, but is simpler and more accurate. The results show fairly good agreement with theory.

  17. Further measurements of K shell photoelectric cross sections for some elements in the range 26<=Z<=41 at 74 keV. [74. 409 keV

    Arora, S K; Allawadhi, K L; Sood, B S [Punjabi Univ., Patiala (India). Dept. of Physics

    1978-12-01

    K shell photoelectric cross sections in elements Fe, Ni, Cu, Zn, As, Se, Br, Sr, Zr and Nb have been measured at 74.409 keV. The targets were irradiated with x radiation and gamma radiation beams. In confirmation with the earlier results, the present results also show fairly good agreement with theory.

  18. Ultraviolet photometry of the Cepheid beta Doradus from the ANS satellite

    Lub, J; Pel, J W; Wesselius, P R

    1979-01-01

    Extensive satellite (ANS) and ground-based (VBLUW-system) photometry is presented for the Cepheid. These data cover the wavelength range 5500-1800 AA. The ANS photometry does not confirm the evidence for shock waves as found by Hutchinson et al. from OAO-2 ultraviolet photometry of beta Doradus. A comparison of the theoretical fluxes of Kurucz with the observed energy distributions of beta Doradus gives very good agreement in the wavelength range 5500-3300 AA. In the ultraviolet the agreement is still satisfactory around maximum light, but towards lower temperatures there appear discrepancies, particularly shortly after light minimum. The difference in these discrepancies on the rising and on the falling branches of the lightcurve indicates that the observed excess ultraviolet flux is probably partly due to that the observed excess ultraviolet flux is probably partly due to dynamical effects in the moving atmosphere of the Cepheid. (25 refs).

  19. CdS/TiO{sub 2} nanocomposite film and its enhanced photoelectric responses to dry air and formaldehyde induced by visible light at room temperature

    Zou, Zhijun, E-mail: zjzou@xynu.edu.cn [Key Laboratory of Advanced Micro/Nano Functional Materials, Department of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000 (China); State Key Laboratory of Material Processing and Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Qiu, Yang [Key Laboratory of Advanced Micro/Nano Functional Materials, Department of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000 (China); Xie, Changsheng [State Key Laboratory of Material Processing and Die & Mould Technology, Nanomaterials and Smart Sensors Research Laboratory, Department of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Xu, Jingjing; Luo, Yongsong; Wang, Chunlei; Yan, Hailong [Key Laboratory of Advanced Micro/Nano Functional Materials, Department of Physics and Electronic Engineering, Xinyang Normal University, Xinyang 464000 (China)

    2015-10-05

    Highlights: • Photoelectric responses of TiO{sub 2} and CdS/TiO{sub 2} to dry air and formaldehyde were tested. • In contrary to TiO{sub 2}, photoelectric response of CdS/TiO{sub 2} obviously increased. • CdS/TiO{sub 2} nanocomposite device exhibits excellent stability to formaldehyde. • CdS/TiO{sub 2} may be a promising material for developing high performance sensor. - Abstract: Photoelectric responses of pure TiO{sub 2} and CdS/TiO{sub 2} nanocomposite devices to dry air and formaldehyde under visible light irradiation at room temperature were investigated in this work. The pure TiO{sub 2} film was firstly prepared by screen printing and CdS/TiO{sub 2} nanocomposite film by the subsequent SILAR process. XRD, FE-SEM, HR-TEM and UV–vis DRS analysis were employed to examine the fundamental characteristics of as-prepared samples. Photoelectric responses of pure TiO{sub 2} device displayed that no obvious photocurrent was observed upon turning the visible light on either in dry air or in formaldehyde. But in contrary to pure TiO{sub 2} device, the photoelectric response of CdS/TiO{sub 2} nanocomposite device has been obviously enhanced. It is the adding of CdS, which works as a sensitizer, that accounts for the enhanced response and makes the CdS/TiO{sub 2} device sensitive to the visible light. Moreover, the CdS/TiO{sub 2} nanocomposite device exhibits excellent stability to formaldehyde. The present work does not only shed light on the photoelectric gas sensing properties of TiO{sub 2} and CdS/TiO{sub 2}, but also suggests that the CdS/TiO{sub 2} nanocomposite may be a promising material for fabricating visible-light-induced photoelectric gas sensors working at room temperature.

  20. FAINT NEAR-ULTRAVIOLET/FAR-ULTRAVIOLET STANDARDS FROM SWIFT/UVOT, GALEX, AND SDSS PHOTOMETRY

    Siegel, Michael H.; Hoversten, Erik A.; Roming, Peter W. A.; Brown, Peter

    2010-01-01

    At present, the precision of deep ultraviolet photometry is somewhat limited by the dearth of faint ultraviolet standard stars. In an effort to improve this situation, we present a uniform catalog of 11 new faint (u ∼ 17) ultraviolet standard stars. High-precision photometry of these stars has been taken from the Sloan Digital Sky Survey and Galaxy Evolution Explorer archives and combined with new data from the Swift Ultraviolet Optical Telescope to provide precise photometric measures extending from the near-infrared to the far-ultraviolet. These stars were chosen because they are known to be hot (20, 000 eff < 50, 000 K) DA white dwarfs with published Sloan spectra that should be photometrically stable. This careful selection allows us to compare the combined photometry and Sloan spectroscopy to models of pure hydrogen atmospheres to both constrain the underlying properties of the white dwarfs and test the ability of white dwarf models to predict the photometric measures. We find that the photometry provides good constraints on white dwarf temperatures, which demonstrates the ability of Swift/UVOT to investigate the properties of hot luminous stars. We further find that the models reproduce the photometric measures in all 11 passbands to within their systematic uncertainties. Within the limits of our photometry, we find the standard stars to be photometrically stable. This success indicates that the models can be used to calibrate additional filters to our standard system, permitting easier comparison of photometry from heterogeneous sources. The largest source of uncertainty in the model fitting is the uncertainty in the foreground reddening curve, a problem that is especially acute in the UV.