WorldWideScience

Sample records for high article visibility

  1. The visibility of scientific misconduct: A review of the literature on retracted journal articles.

    Science.gov (United States)

    Hesselmann, Felicitas; Graf, Verena; Schmidt, Marion; Reinhart, Martin

    2017-10-01

    Retractions of scientific articles are becoming the most relevant institution for making sense of scientific misconduct. An increasing number of retracted articles, mainly attributed to misconduct, is currently providing a new empirical basis for research about scientific misconduct. This article reviews the relevant research literature from an interdisciplinary context. Furthermore, the results from these studies are contextualized sociologically by asking how scientific misconduct is made visible through retractions. This study treats retractions as an emerging institution that renders scientific misconduct visible, thus, following up on the sociology of deviance and its focus on visibility. The article shows that retractions, by highlighting individual cases of misconduct and general policies for preventing misconduct while obscuring the actors and processes through which retractions are effected, produce highly fragmented patterns of visibility. These patterns resemble the bifurcation in current justice systems.

  2. The visibility of high-redshift galaxies

    International Nuclear Information System (INIS)

    Phillipps, S.; Davies, J.I.; Disney, M.J.

    1990-01-01

    The most visible galaxies - that is, those which have the largest apparent sizes and isophotal luminosities when seen at a given distance - are those with a particular observed surface brightness. Extending this argument to high-redshift galaxies, it is clear that this optimum surface brightness moves progressively to brighter intrinsic surface brightnesses, so as to counteract the effect of K-corrections and cosmological dimming. Thus the galaxies appearing in faint surveys will be from a population distinctly different from those 'normal' galaxies observed nearby. Galaxies in deep surveys are more likely to be spirals and to be of high surface brightness. This has very important implications for observational studies of galaxy evolution. (author)

  3. Visible high power fiber coupled diode lasers

    Science.gov (United States)

    Köhler, Bernd; Drovs, Simon; Stoiber, Michael; Dürsch, Sascha; Kissel, Heiko; Könning, Tobias; Biesenbach, Jens; König, Harald; Lell, Alfred; Stojetz, Bernhard; Löffler, Andreas; Strauß, Uwe

    2018-02-01

    In this paper we report on further development of fiber coupled high-power diode lasers in the visible spectral range. New visible laser modules presented in this paper include the use of multi single emitter arrays @ 450 nm leading to a 120 W fiber coupled unit with a beam quality of 44 mm x mrad, as well as very compact modules with multi-W output power from 405 nm to 640 nm. However, as these lasers are based on single emitters, power scaling quickly leads to bulky laser units with a lot of optical components to be aligned. We also report on a new approach based on 450 nm diode laser bars, which dramatically reduces size and alignment effort. These activities were performed within the German government-funded project "BlauLas": a maximum output power of 80 W per bar has been demonstrated @ 450 nm. We show results of a 200 μm NA0.22 fiber coupled 35 W source @ 450 nm, which has been reduced in size by a factor of 25 compared to standard single emitter approach. In addition, we will present a 200 μm NA0.22 fiber coupled laser unit with an output power of 135 W.

  4. High power diode lasers converted to the visible

    DEFF Research Database (Denmark)

    Jensen, Ole Bjarlin; Hansen, Anders Kragh; Andersen, Peter E.

    2017-01-01

    High power diode lasers have in recent years become available in many wavelength regions. However, some spectral regions are not well covered. In particular, the visible spectral range is lacking high power diode lasers with good spatial quality. In this paper, we highlight some of our recent...... results in nonlinear frequency conversion of high power near infrared diode lasers to the visible spectral region....

  5. High visibility temporal ghost imaging with classical light

    Science.gov (United States)

    Liu, Jianbin; Wang, Jingjing; Chen, Hui; Zheng, Huaibin; Liu, Yanyan; Zhou, Yu; Li, Fu-li; Xu, Zhuo

    2018-03-01

    High visibility temporal ghost imaging with classical light is possible when superbunching pseudothermal light is employed. In the numerical simulation, the visibility of temporal ghost imaging with pseudothermal light, equaling (4 . 7 ± 0 . 2)%, can be increased to (75 ± 8)% in the same scheme with superbunching pseudothermal light. The reasons for that the retrieved images are different for superbunching pseudothermal light with different values of degree of second-order coherence are discussed in detail. It is concluded that high visibility and high quality temporal ghost image can be obtained by collecting sufficient number of data points. The results are helpful to understand the difference between ghost imaging with classical light and entangled photon pairs. The superbunching pseudothermal light can be employed to improve the image quality in ghost imaging applications.

  6. Article

    African Journals Online (AJOL)

    2009-06-22

    Jun 22, 2009 ... of the 80% of pregnant women having access to prevention of mother-to-child ... breviation for a complicated statement that includes, among other things, moral ... duce an outcome where frustrations of welfare interests become .... Article abortion and its related issues of moral status in prenatal life. The.

  7. Comparison of Sociometrically High Visibility Rejected and Low Visibility Rejected Children on Teacher, Parent, and Self-Rating Measures.

    Science.gov (United States)

    Neighbor, Jonelle C.

    The study looked at differences between groups of children identified as high visibility rejected (HVR) and low visibility rejected (LVR) on a sociometric measure with 952 fourth, fifth, and sixth grade students. Questionnaires were analyzed to determine the number of positive and negative nominations from peers received by each child. HVR…

  8. Nanosecond high-power dense microplasma switch for visible light

    Energy Technology Data Exchange (ETDEWEB)

    Bataller, A., E-mail: bataller@physics.ucla.edu; Koulakis, J.; Pree, S.; Putterman, S. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095 (United States)

    2014-12-01

    Spark discharges in high-pressure gas are known to emit a broadband spectrum during the first 10 s of nanoseconds. We present calibrated spectra of high-pressure discharges in xenon and show that the resulting plasma is optically thick. Laser transmission data show that such a body is opaque to visible light, as expected from Kirchoff's law of thermal radiation. Nanosecond framing images of the spark absorbing high-power laser light are presented. The sparks are ideal candidates for nanosecond, high-power laser switches.

  9. Article

    African Journals Online (AJOL)

    2011-06-24

    Jun 24, 2011 ... southern Africa. Cultural norms, values and beliefs impact in very significant ways .... extremely high rates of HIV/AIDS and tuberculosis in South Africa. The vast .... Campbell J. The Masks of God: Primitive Mythology. London: ...

  10. Article

    African Journals Online (AJOL)

    2012-12-01

    Dec 1, 2012 ... Argentina, China, India, Russia and South Africa (SA).2 They have lured many patients ... Increasing use of social media has made it easier for bogus doctors .... Biological medicines are a highly specialised class of medicine,.

  11. Articles

    African Journals Online (AJOL)

    2011-09-01

    Sep 1, 2011 ... that an exchange of information can occur at a colony, ... events, low adult survival rates and high emigration rates, and these sinks are therefore prone to ..... Eurasian griffons Gyps fulvus in the island of Crete, Greece. Wildlife ...

  12. Article

    African Journals Online (AJOL)

    ment when they become fully qualified to treat patients, neither do they become ... standards, including a strong commitment to the well-being of oth- ers, and a high .... Such situ- ations are, unfortunately, all too common,10 and students under-.

  13. articles

    African Journals Online (AJOL)

    denise

    2011-12-04

    Dec 4, 2011 ... speed, learning and memory, attention and working memory, speech and language, executive functioning ... verbal and visual memory are considered highly sensitive indicators of HAND. These episodic ... indicate that basic receptive (e.g. auditory comprehension) and expressive (e.g. repetition) language ...

  14. Article

    African Journals Online (AJOL)

    GREATBENSON

    among librarians in public libraries towards integrating social media to library service delivery is ... social media policy, low level of ICT literacy among librarians in public libraries are the major ..... Efforts should be made by heads of public libraries to ensure that high level ICTs ... of social media for relationship marketing.

  15. High accuracy wavelength calibration for a scanning visible spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Scotti, Filippo; Bell, Ronald E. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2010-10-15

    Spectroscopic applications for plasma velocity measurements often require wavelength accuracies {<=}0.2 A. An automated calibration, which is stable over time and environmental conditions without the need to recalibrate after each grating movement, was developed for a scanning spectrometer to achieve high wavelength accuracy over the visible spectrum. This method fits all relevant spectrometer parameters using multiple calibration spectra. With a stepping-motor controlled sine drive, an accuracy of {approx}0.25 A has been demonstrated. With the addition of a high resolution (0.075 arc sec) optical encoder on the grating stage, greater precision ({approx}0.005 A) is possible, allowing absolute velocity measurements within {approx}0.3 km/s. This level of precision requires monitoring of atmospheric temperature and pressure and of grating bulk temperature to correct for changes in the refractive index of air and the groove density, respectively.

  16. LED-based high-speed visible light communications

    Science.gov (United States)

    Chi, Nan; Shi, Meng; Zhao, Yiheng; Wang, Fumin; Shi, Jianyang; Zhou, Yingjun; Lu, Xingyu; Qiao, Liang

    2018-01-01

    We are seeing a growing use of light emitting diodes (LEDs) in a range of applications including lighting, TV and backlight board screen, display etc. In comparison with the traditional incandescent and fluorescent light bulbs, LEDs offer long life-space, much higher energy efficiency, high performance cost ratio and above all very fast switching capability. LED based Visible Light Communications (VLC) is an emerging field of optical communications that focuses on the part of the electromagnetic spectrum that humans can see. Depending on the transmission distance, we can divide the whole optical network into two categories, long haul and short haul. Visible light communication can be a promising candidate for short haul applications. In this paper, we outline the configuration of VLC, its unique benefits, and describe the state of the art research contributions consisting of advanced modulation formats including adaptive bit loading OFDM, carrierless amplitude and phase (CAP), pulse amplitude modulation (PAM) and single carrier Nyquist, linear equalization and nonlinear distortion mitigation based on machine learning, quasi-balanced coding and phase-shifted Manchester coding. These enabling technologies can support VLC up to 10Gb/s class free space transmission.

  17. Highly cited orthodontic articles from 2000 to 2015.

    Science.gov (United States)

    Prevezanos, Panagiotis; Tsolakis, Apostolos I; Christou, Panagiotis

    2018-01-01

    Identification of highly cited articles based on the h-index and its properties is important for the evaluation of the past, present, and future of any research discipline. In this study, we aimed to identify the h-classic articles in orthodontics. One search on the Web of Science identified all articles from 2000 to 2015 in the 89 journals indexed by the 2015 InCites Journal Citation Reports in the scientific area "dentistry, oral surgery, and medicine." A second search was performed in the Web of Science using all mesh terms related to orthodontics. Then, we applied the h-classic method to select the recent articles with the greatest scientific impact in orthodontics. Eighty articles were considered as h-classic articles. They were published in 20 of the 89 dental journals of the 2015 InCites Journal Citation Reports list. Only 36 articles appeared in orthodontic journals: 23 in the American Journal of Orthodontics & Dentofacial Orthopedics (28.8%), 7 in The Angle Orthodontist (8.8%), and 6 in European Journal of Orthodontics (7.5%). Thirty-eight articles originated from Europe, 28 from the Americas, and 14 from the Middle East and Asia. More than half of fundamental orthodontic research is published in nonorthodontic journals showing that our field is currently limited, and interactions with other research fields should be sought to increase orthodontic research importance and appeal. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  18. Articles for high temperature service and methods for their manufacture

    Science.gov (United States)

    Sarrafi-Nour, Reza; Meschter, Peter Joel; Johnson, Curtis Alan; Luthra, Krishan Lal; Rosenzweig, Larry Steven

    2016-06-14

    An article for use in aggressive environments is presented. In one embodiment, the article comprises a substrate and a self-sealing and substantially hermetic sealing layer comprising an alkaline-earth aluminosilicate disposed over the bondcoat. The substrate may be any high-temperature material, including, for instance, silicon-bearing ceramics and ceramic matrix composites. A method for making such articles is also presented. The method comprises providing a substrate; disposing a self-sealing alkaline-earth aluminosilicate layer over the substrate; and heating the sealing layer to a sealing temperature at which at least a portion of the sealing layer will flow.

  19. Process for preparing polyolefin gel articles as well as for preparing herefrom articles having a high tensile strength and modulus

    NARCIS (Netherlands)

    1990-01-01

    A process is described for the preparation of highly stretchable high-molecular weight polyolefin gel articles and polyolefin gel articles prepared therefrom having combined high tensile strength and high modulus, wherein an initial shaped article of the polyolefin is exposed to or contacted with a

  20. Characteristics of Highly Cited Articles in Interventional Cardiology.

    Science.gov (United States)

    Khan, Muhammad Shahzeb; Usman, Muhammad Shariq; Fatima, Kaneez; Hashmani, Nauman; Siddiqi, Tariq Jamal; Riaz, Haris; Khan, Abdur Rahman; Khosa, Faisal

    2017-12-01

    Citation classics have been published in many fields of medicine; however, none have focused on interventional cardiology. The goal of this study was to identify the top 100 articles in the field of interventional cardiology and highlight their important trends and characteristics. The Scopus database was used by 2 independent reviewers to extract the top 100 articles using a variety of keywords. We found articles published between 1953 and 2012. Majority (n = 78) of the top 100 articles were published between 1996 and 2010, and the United States was affiliated with the highest number of articles in our list (n = 68). Over half (n = 54) the articles were funded. Private funding was correlated with higher citations (p = 0.036). A third (n = 33) of the papers had authors with conflicts of interest; however, conflict of interest had no effect on citations (p = 0.837). Majority (n = 57) of the articles studied coronary angioplasty and stenting; followed by coronary angiography (n = 14). Women were underrepresented, with only 11 female first authors in the top 100 papers, and only 1 female in the list of top authors who had 5 or more publications. In conclusion, the following features define the typical highly cited article in interventional cardiology-a clinical trial conducted in the United States, which studies angioplasty, and has been published relatively recently in a high-impact journal by a male first author. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. High-visibility infrared beacons for IFF and combat ID

    Science.gov (United States)

    Pralle, Martin; Puscasu, Irina; Johnson, Edward; Loges, Peter; Melnyk, James

    2005-05-01

    A new kind of Identification Friend or Foe (IFF) infrared beacon has been demonstrated. The omni-directional beacon consists of a pyramidal array of 1W pulsIR thermal light sources. Operating at a total power of 84W, the beacon can be used to track and identify surface vehicles and personnel with a recognition range of up to 6 miles on the battlefield and in urban environments or the marine boundary layer. Advanced photonic technology enables the beacon to be seen only while using a 3-5 μm or 8-12 μm thermal imaging system. There is no visible or near-IR emission to betray the location of the beacon. The beacon is rugged and will operate from -40 to 50°C ambient temperature, 0-100% relative humidity, 0 - 10,000 ft altitude, and meets MIL-STD 810F and MIL-STD 461E.

  2. HighWire Free Online Full-text Articles

    Science.gov (United States)

    Journal of Lipid Research all articles after 12 months Journal of Medical Ethics all articles 1 Jan 1975 Anticancer Research all articles after 2 years every Jan. Antimicrobial Agents and Chemotherapy all articles BMJ Open Diabetes Research & Care free site BMJ Open Gastroenterology free site BMJ Open

  3. Article Article

    African Journals Online (AJOL)

    2012-12-03

    Dec 3, 2012 ... Article. The use of standardised patients (SPs) in medical education is well ... those taught using inpatients6 and virtual patients.7 The use of the ..... the reality that principles taught in theory do not always translate into the.

  4. Development of ultra high speed photographic system using high repetition rate visible laser

    International Nuclear Information System (INIS)

    Lee, Jong Min; Cha, Byung Hun; Kim, Sung Ho; Kim, Jung Bog; Lim, Chang Hwan; Cha, Hyung Ki; Song, Kyu Seok; Lee, Byung Deok; Rhi, Jong Hoon; Baik, Dae Hyun; Han, Jae Min; Rho, Si Pyo; Lee, Byung Cheol; Jeong, Do Yung; Choi, An Seong; Jeong, Chan Ik; Park, Dae Ung; Jeong, Sung Min; Lee, Sang Kil; Kim, Heon Jun; Jang, Rae gak; Jo, Do Hun; Park, Min Young

    1992-12-01

    The goal of this project is to develop and commercialize a high speed photographic system equipped with a high repetition rate visible laser. The developed system provides the characteristics of high time resolution and large number of frames. The system consists of 10 W air cooled CVL or a 30 W water cooled CVL, a rotating drum-type high speed camera with the framing rate of 35,000 fps, and a automatic control device. The system has the performance of 10 nsec time resolution, 35,000 fps framing rate, and 250 picture frames. The high speed photographic systems are widely applied to the fields such as high-efficient engine development, high-speed vibration analysis, shock wave propagation study, flow visualization analysis, weapon development, etc. (Author)

  5. The 2007 click it or ticket high-visibility seat belt mobilization : traffic tech.

    Science.gov (United States)

    2010-09-01

    In May 2007 the National Highway Traffic Safety Administration : sponsored the fifth national Click It or Ticket (CIOT) : high-visibility seat belt enforcement mobilization, which followed : the CIOT program model of earned and paid media : publicizi...

  6. Visible light photon counters (VLPCs) for high rate tracking medical imaging and particle astrophysics

    International Nuclear Information System (INIS)

    Atac, M.

    1998-02-01

    This paper is on the operation principles of the Visible Light Photon Counters (VLPCs), application to high luminosity-high multiplicity tracking for High Energy Charged Particle Physics, and application to Medical Imaging and Particle Astrophysics. The VLPCs as Solid State Photomultipliers (SSPMS) with high quantum efficiency can detect down to single photons very efficiently with excellent time resolution and high avalanche gains

  7. Making Invisible Histories Visible

    Science.gov (United States)

    Hanssen, Ana Maria

    2012-01-01

    This article features Omaha Public Schools' "Making Invisible Histories Visible" program, or MIHV. Omaha's schools have a low failure rate among 8th graders but a high one among high school freshmen. MIHV was created to help at-risk students "adjust to the increased demands of high school." By working alongside teachers and…

  8. articles articles

    African Journals Online (AJOL)

    of the challenges the child and adolescent mental health (CAMH) service faces is the high ... disorder plus co-morbid substance use disorder (SUD)), which prolongs treatment ... was associated with prodromal symptoms in adolescents and that this effect was not .... Other (Adjustment disorder, Anxiety disorder, V code). 8.

  9. Cutting and drilling studies using high power visible lasers

    International Nuclear Information System (INIS)

    Kautz, D.D.; Dragon, E.P.; Werve, M.E.; Hargrove, R.S.; Warner, B.E.

    1993-01-01

    High power and radiance laser technologies developed at Lawrence Livermore National Laboratory such as copper-vapor and dye lasers show great promise for material processing tasks. Evaluation of models suggests significant increases in welding, cutting, and drilling capabilities, as well as applications in emerging technologies such as micromachining, surface treatment, and stereolithography. Copper lasers currently operate at 1.8 kW output at approximately three times the diffraction limit and achieve mean time between failures of more than 1,000 hours. Dye lasers have near diffraction limited beam quality at greater than 1.0 kW. Results from cutting and drilling studies in titanium and stainless steel alloys show that cuts and holes with extremely fine features can be made with dye and copper-vapor lasers. High radiance beams produce low distortion and small heat-affected zones. The authors have accomplished very high aspect ratios (> 60:1) and features with micron scale (5-50 μm) sizes. The paper gives a description of the equipment; discusses cutting theory; and gives experimental results of cutting and drilling studies on Ti-6Al-4V and 304 stainless steel

  10. High-Performance Visible-Blind UV Phototransistors Based on n-Type Naphthalene Diimide Nanomaterials.

    Science.gov (United States)

    Song, Inho; Lee, Seung-Chul; Shang, Xiaobo; Ahn, Jaeyong; Jung, Hoon-Joo; Jeong, Chan-Uk; Kim, Sang-Wook; Yoon, Woojin; Yun, Hoseop; Kwon, O-Pil; Oh, Joon Hak

    2018-04-11

    This study investigates the performance of single-crystalline nanomaterials of wide-band gap naphthalene diimide (NDI) derivatives with methylene-bridged aromatic side chains. Such materials are found to be easily used as high-performance, visible-blind near-UV light detectors. NDI single-crystalline nanoribbons are assembled using a simple solution-based process (without solvent-inclusion problems), which is then applied to organic phototransistors (OPTs). Such OPTs exhibit excellent n-channel transistor characteristics, including an average electron mobility of 1.7 cm 2 V -1 s -1 , sensitive UV detection properties with a detection limit of ∼1 μW cm -2 , millisecond-level responses, and detectivity as high as 10 15 Jones, demonstrating the highly sensitive organic visible-blind UV detectors. The high performance of our OPTs originates from the large face-to-face π-π stacking area between the NDI semiconducting cores, which is facilitated by methylene-bridged aromatic side chains. Interestingly, NDI-based nanoribbon OPTs exhibit a distinct visible-blind near-UV detection with an identical detection limit, even under intense visible light illumination (for example, 10 4 times higher intensity than UV light intensity). Our findings demonstrate that wide-band gap NDI-based nanomaterials are highly promising for developing high-performance visible-blind UV photodetectors. Such photodetectors could potentially be used for various applications including environmental and health-monitoring systems.

  11. Highly Transparent, Visible-Light Photodetector Based on Oxide Semiconductors and Quantum Dots.

    Science.gov (United States)

    Shin, Seung Won; Lee, Kwang-Ho; Park, Jin-Seong; Kang, Seong Jun

    2015-09-09

    Highly transparent phototransistors that can detect visible light have been fabricated by combining indium-gallium-zinc oxide (IGZO) and quantum dots (QDs). A wide-band-gap IGZO film was used as a transparent semiconducting channel, while small-band-gap QDs were adopted to absorb and convert visible light to an electrical signal. Typical IGZO thin-film transistors (TFTs) did not show a photocurrent with illumination of visible light. However, IGZO TFTs decorated with QDs showed enhanced photocurrent upon exposure to visible light. The device showed a responsivity of 1.35×10(4) A/W and an external quantum efficiency of 2.59×10(4) under illumination by a 635 nm laser. The origin of the increased photocurrent in the visible light was the small band gap of the QDs combined with the transparent IGZO films. Therefore, transparent phototransistors based on IGZO and QDs were fabricated and characterized in detail. The result is relevant for the development of highly transparent photodetectors that can detect visible light.

  12. High-visibility time-bin entanglement for testing chained Bell inequalities

    Science.gov (United States)

    Tomasin, Marco; Mantoan, Elia; Jogenfors, Jonathan; Vallone, Giuseppe; Larsson, Jan-Åke; Villoresi, Paolo

    2017-03-01

    The violation of Bell's inequality requires a well-designed experiment to validate the result. In experiments using energy-time and time-bin entanglement, initially proposed by Franson in 1989, there is an intrinsic loophole due to the high postselection. To obtain a violation in this type of experiment, a chained Bell inequality must be used. However, the local realism bound requires a high visibility in excess of 94.63% in the time-bin entangled state. In this work, we show how such a high visibility can be reached in order to violate a chained Bell inequality with six, eight, and ten terms.

  13. Observation of visible and uv magnetic dipole transitions in highly charged xenon and barium

    International Nuclear Information System (INIS)

    Morgan, C.A.; Serpa, F.G.; Takacs, E.; Meyer, E.S.; Gillaspy, J.D.; Sugar, J.; Roberts, J.R.; Brown, C.M.; Feldman, U.

    1995-01-01

    We have observed an unusual transition which is predicted to result in visible and near-uv emission from very highly charged titaniumlike ions spanning the entire upper half of the periodic table. Measurements of the wavelengths of the 3d 4 D 2 - 5 D 3 transitions in Ba +34 and Xe +32 are in surprisingly poor agreement with ab initio calculations. This work was carried out in an electron beam ion trap and demonstrates that such a device can be an important tool for visible spectroscopy of highly charged ions

  14. 2 original article non-attenuation of highly pathogenic avian

    African Journals Online (AJOL)

    Dr Oboro VO

    AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JANUARY 2010. ISBN 1595-689X ... NON-ATTENUATION OF HIGHLY PATHOGENIC AVIAN INFLUENZA. H5N1 BY .... Diagnostic PCR was conducted to determine ...

  15. Printable photonic crystals with high refractive index for applications in visible light

    International Nuclear Information System (INIS)

    Calafiore, Giuseppe; Mejia, Camilo A; Munechika, Keiko; Peroz, Christophe; Piña-Hernandez, Carlos; Fillot, Quentin; Dhuey, Scott; Sassolini, Simone; Salvadori, Filippo; Cabrini, Stefano

    2016-01-01

    Nanoimprint lithography (NIL) of functional high-refractive index materials has proved to be a powerful candidate for the inexpensive manufacturing of high-resolution photonic devices. In this paper, we demonstrate the fabrication of printable photonic crystals (PhCs) with high refractive index working in the visible wavelengths. The PhCs are replicated on a titanium dioxide-based high-refractive index hybrid material by reverse NIL with almost zero shrinkage and high-fidelity reproducibility between mold and printed devices. The optical responses of the imprinted PhCs compare very well with those fabricated by conventional nanofabrication methods. This study opens the road for a low-cost manufacturing of PhCs and other nanophotonic devices for applications in visible light. (paper)

  16. Degradation of fluorescent high-visibility colors used in safety garments for the Australian railway industry.

    Science.gov (United States)

    Vijayan, Arun; Islam, Saniyat; Jones, Michael; Padhye, Rajiv; Arnold, Lyndon

    2016-02-01

    This study investigated the compliance of four fluorescent orange high-visibility garment substrates that are predominantly used in the Australian railway industry. While Special Purpose Orange (SPO), a shade of the Fluorescent orange (Fl-orange) is recommended by most Australian states as the high-visibility background color of a safety garment, there appear to be variations in the background color of clothing used by line-workers and rail contractors. The color of the garment was assessed for compliance with the Australian Standard AS/NZS 1906.2.2010 for high-visibility materials for safety garments. The results were also compared with ANSI Z535.2011 and BS EN ISO 20471.2013 Standards. Photometric and colorimetric assessments of the background color of the garment substrates were performed using a spectrophotometer and were evaluated for compliance with the Standards after washing and exposure to UV. The spectrophotometry measurements showed that Fl-orange background color for all samples except one complied with the AS/NZS 1906.2 Standard for daytime high-visibility garments after 20 washes but failed to comply after exposure to UV. It was also found that the chromaticity coordinates of the corners of the Fl-orange color space, specified in the AS/NZS 1906.4.2010 Standard are much wider and yellower when compared with the ANSI Z535.1.2011 and BS EN ISO 20471.2013 Standards. The sample that failed to comply with the Australian and American Standards however complied with the ISO Standard. Irrespective of the Standard used, the research has shown the degrading effect of washing and light exposure and raises the questions as to how regularly, and under what conditions high-visibility garments need to be replaced. These findings will provide information for safety garment manufacturers about the characteristics and performance of high-visibility safety garments which make them conspicuous during daytime use. This research recommends that colors for railway workers

  17. Facile synthesis of cobalt-doped zinc oxide thin films for highly efficient visible light photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Altintas Yildirim, Ozlem, E-mail: ozlemaltintas@gmail.com [Department of Metallurgical and Materials Engineering, Selcuk University, Konya (Turkey); Arslan, Hanife; Sönmezoğlu, Savaş [Department of Metallurgical and Materials Engineering, Karamanoglu Mehmetbey University, Karaman (Turkey); Nanotechnology R& D Laboratory, Karamanoglu Mehmetbey University, Karaman (Turkey)

    2016-12-30

    Highlights: • Photocatalytically active Co-ZnO thin film was obtained by sol-gel method. • Co{sup 2+} doping narrowed the band gap of pure ZnO to an extent of 3.18 eV. • Co-ZnO was effective in MB degradation under visible light. • Optimum dopant content to show high performance was 3 at.%. - Abstract: Cobalt-doped zinc oxide (Co:ZnO) thin films with dopant contents ranging from 0 to 5 at.% were prepared using the sol–gel method, and their structural, morphological, optical, and photocatalytic properties were characterized. The effect of the dopant content on the photocatalytic properties of the films was investigated by examining the degradation behavior of methylene blue (MB) under visible light irradiation, and a detailed investigation of their photocatalytic activities was performed by determining the apparent quantum yields (AQYs). Co{sup 2+} ions were observed to be substitutionally incorporated into Zn{sup 2+} sites in the ZnO crystal, leading to lattice parameter constriction and band gap narrowing due to the photoinduced carriers produced under the visible light irradiation. Thus, the light absorption range of the Co:ZnO films was improved compared with that of the undoped ZnO film, and the Co:ZnO films exhibited highly efficient photocatalytic activity (∼92% decomposition of MB after 60-min visible light irradiation for the 3 at.% Co:ZnO film). The AQYs of the Co:ZnO films were greatly enhanced under visible light irradiation compared with that of the undoped ZnO thin film, demonstrating the effect of the Co doping level on the photocatalytic activity of the films.

  18. Near UV-visible line emission from tungsten highly-charged ions in Large Helical Device

    International Nuclear Information System (INIS)

    Kato, D.; Sakaue, H.A.; Murakami, I.; Goto, M.; Oishi, T.; Morita, S.; Fujii, K.; Nakamura, N.; Koike, F.; Sasaki, Akira; Ding, X.-B.; Dong, C.-Z.

    2015-01-01

    Wavelengths of emission lines from tungsten highly-charged ions have been precisely measured in near UV-visible range (320 - 356 nm and 382 - 402 nm) at Large Helical Device (LHD) by tungsten pellet injection. The tungsten emission lines were assigned based on its line-integrated intensity profiles on a poloidal cross section. The ground-term magnetic-dipole (M1) lines of W 26+,27+ and an M1 line of a metastable excited state of W 28+ , whose wavelengths have been determined by measurements using electron-beam-ion-traps (EBITs), are identified in the LHD spectra. The present results partially compliment wavelength data of tungsten highly-charged ions in the near UV-visible range. (author)

  19. High-efficiency and low-loss gallium nitride dielectric metasurfaces for nanophotonics at visible wavelengths

    Science.gov (United States)

    Emani, Naresh Kumar; Khaidarov, Egor; Paniagua-Domínguez, Ramón; Fu, Yuan Hsing; Valuckas, Vytautas; Lu, Shunpeng; Zhang, Xueliang; Tan, Swee Tiam; Demir, Hilmi Volkan; Kuznetsov, Arseniy I.

    2017-11-01

    The dielectric nanophotonics research community is currently exploring transparent material platforms (e.g., TiO2, Si3N4, and GaP) to realize compact high efficiency optical devices at visible wavelengths. Efficient visible-light operation is key to integrating atomic quantum systems for future quantum computing. Gallium nitride (GaN), a III-V semiconductor which is highly transparent at visible wavelengths, is a promising material choice for active, nonlinear, and quantum nanophotonic applications. Here, we present the design and experimental realization of high efficiency beam deflecting and polarization beam splitting metasurfaces consisting of GaN nanostructures etched on the GaN epitaxial substrate itself. We demonstrate a polarization insensitive beam deflecting metasurface with 64% and 90% absolute and relative efficiencies. Further, a polarization beam splitter with an extinction ratio of 8.6/1 (6.2/1) and a transmission of 73% (67%) for p-polarization (s-polarization) is implemented to demonstrate the broad functionality that can be realized on this platform. The metasurfaces in our work exhibit a broadband response in the blue wavelength range of 430-470 nm. This nanophotonic platform of GaN shows the way to off- and on-chip nonlinear and quantum photonic devices working efficiently at blue emission wavelengths common to many atomic quantum emitters such as Ca+ and Sr+ ions.

  20. Highly efficient holograms based on c-Si metasurfaces in the visible range.

    Science.gov (United States)

    Martins, Augusto; Li, Juntao; da Mota, Achiles F; Wang, Yin; Neto, Luiz G; do Carmo, João P; Teixeira, Fernando L; Martins, Emiliano R; Borges, Ben-Hur V

    2018-04-16

    This paper reports on the first hologram in transmission mode based on a c-Si metasurface in the visible range. The hologram shows high fidelity and high efficiency, with measured transmission and diffraction efficiencies of ~65% and ~40%, respectively. Although originally designed to achieve full phase control in the range [0-2π] at 532 nm, these holograms have also performed well at 444.9 nm and 635 nm. The high tolerance to both fabrication and wavelength variations demonstrate that holograms based on c-Si metasurfaces are quite attractive for diffractive optics applications, and particularly for full-color holograms.

  1. High-performance visible/UV CCD focal plane technology for spacebased applications

    Science.gov (United States)

    Burke, B. E.; Mountain, R. W.; Gregory, J. A.; Huang, J. C. M.; Cooper, M. J.; Savoye, E. D.; Kosicki, B. B.

    1993-01-01

    We describe recent technology developments aimed at large CCD imagers for space based applications in the visible and UV. Some of the principal areas of effort include work on reducing device degradation in the natural space-radiation environment, improvements in quantum efficiency in the visible and UV, and larger-device formats. One of the most serious hazards for space based CCD's operating at low signal levels is the displacement damage resulting from bombardment by energetic protons. Such damage degrades charge-transfer efficiency and increases dark current. We have achieved improved hardness to proton-induced displacement damage by selective ion implants into the CCD channel and by reduced temperature of operation. To attain high quantum efficiency across the visible and UV we have developed a technology for back-illuminated CCD's. With suitable antireflection (AR) coatings such devices have quantum efficiencies near 90 percent in the 500-700-nm band. In the UV band from 200 to 400 nm, where it is difficult to find coatings that are sufficiently transparent and can provide good matching to the high refractive index of silicon, we have been able to substantially increase the quantum efficiency using a thin film of HfO2 as an AR coating. These technology efforts were applied to a 420 x 420-pixel frame-transfer imager, and future work will be extended to a 1024 x 1024-pixel device now under development.

  2. Measurements of visible forbidden lines and ion distributions of tungsten highly charged ions at the LHD

    International Nuclear Information System (INIS)

    Kato, D.; Sakaue, H.A.; Murakami, I.; Goto, M.; Morita, S.; Nakamura, N.; Koike, F.; Sasaki, Akira; Ding, X.-B.; Dong, C.-Z.

    2013-01-01

    Visible lines, which are presumably associated with forbidden lines from tungsten highly charged ions, were clearly observed in a spectrum of 370 - 410 nm recorded shortly after a tungsten pellet injection at the LHD. One of the measured lines has been assigned to a magnetic-dipole (M1) line of the ground-term fine-structure transition of W 26+ . Photon emission was observed at 44 lines of sight divided along the vertical direction of a horizontally elongated poloidal cross section of the LHD plasma. The line-integrated intensity of the lines along each line of sight indicates peaked profiles near the plasma center, while visible line emissions of neutral hydrogen and helium recoded in the same sampling time have a maximum located in the peripheral region of the poloidal cross section. (author)

  3. Visible luminescence from highly textured Tb{sup 3+} doped RF sputtered zinc oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Sreedharan, R. Sreeja; Krishnan, R. Reshmi; Bose, R. Jolly; Kavitha, V.S.; Suresh, S. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Vinodkumar, R. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Department of Physics, University College, Thiruvananthapuram, Kerala (India); Sudheer, S.K. [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India); Pillai, V.P. Mahadevan, E-mail: vpmpillai9@gmail.com [Department of Optoelectronics, University of Kerala, Thiruvananthapuram 695581, Kerala (India)

    2017-04-15

    Highly transparent, luminescent, c-axis oriented Tb{sup 3+} doped ZnO films are prepared by RF magnetron sputtering technique. The structural, morphological, optical and luminescence properties of these films are investigated as a function of Tb{sup 3+} doping concentration by X-ray diffraction (XRD), micro-Raman spectroscopy, atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), spectroscopic ellipsometry, UV-Visible spectroscopy and photoluminescence spectroscopy. The as-deposited films are found to be highly crystalline with wurtzite hexagonal phase of ZnO. The characteristic features of hexagonal wurtzite structure of ZnO, particularly the appearance of non-polar E{sub 2} modes are easily identified from the Raman spectra of the films. The surface morphology of the films revealed by FESEM and AFM images present a dense distribution of grains. The elemental analysis carried out using energy dispersive X-ray (EDX) spectra confirms the incorporation of Tb{sup 3+} ions in the ZnO lattice. The films are highly transparent in the visible region. Using ellipsometric analysis, the variation of refractive index, dielectric constant and thickness of the films are studied as a function of Tb{sup 3+} doping concentration. The photoluminescence spectra of the Tb{sup 3+} doped ZnO films recorded using an excitation radiation of wavelength 325 nm from a He-Cd laser exhibit visible luminescence ~430, 490, 516 and 542 nm. The origin of visible emissions ~490 and 542 nm in the doped films can be attributed to 5D{sub 4}→7F{sub 6} and 5D{sub 4}→7F{sub 5} transition of Tb{sup 3+} ion respectively. The intensity of the emission at 542 nm is found to be decreasing at higher doping concentration due to concentration quenching effect. The blue emission in the films can be attributed to the electron transition from shallow donor level formed by interstitial Zn atoms to the top of the valence band. The origin of the visible emission ~516 nm is attributed

  4. Infrared and visible laser spectroscopy for highly-charged Ni-like ions

    Science.gov (United States)

    Ralchenko, Yuri

    2017-10-01

    Application of visible or infrared (IR) lasers for spectroscopy of highly-charged ions (HCI) has not been particularly extensive so far due to a mismatch in typical energies. We show here that the energy difference between the two lowest levels within the first excited configuration 3d9 4 s in Ni-like ions of heavy elements from ZN = 60 to ZN = 92 is within the range of visible or near-IR lasers. The wavelengths of these transitions are calculated within the relativistic model potential formalism and compared with other theoretical and limited experimental data. Detailed collisional-radiative simulations of non-Maxwellian and thermal plasmas are performed showing that photopumping between these levels using relatively moderate lasers is sufficient to provide a two-order of magnitude increase of the pumped level population. This accordingly results in a similar rise of the X-ray line intensity thereby allowing control of X-ray emission with visible/IR lasers.

  5. Tunable High Harmonic Generation driven by a Visible Optical Parametric Amplifier

    Directory of Open Access Journals (Sweden)

    Keathley P.

    2013-03-01

    Full Text Available We studied high-harmonic generation (HHG in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 μJ energy at 1-kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping energy, duration and beam size constant, we experimentally studied the scaling law of conversion efficiency and cut-off energy with the driver wavelength in argon and helium respectively. Our measurements show a λ−5.9±0.9 wavelength dependence of the conversion efficiency and a λ1.7±0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source and changing the gas, the high order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ~25 eV and ~100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  6. A high-speed, eight-wavelength visible light-infrared pyrometer for shock physics experiments

    Science.gov (United States)

    Wang, Rongbo; Li, Shengfu; Zhou, Weijun; Luo, Zhen-Xiong; Meng, Jianhua; Tian, Jianhua; He, Lihua; Cheng, Xianchao

    2017-09-01

    An eight-channel, high speed pyrometer for precise temperature measurement is designed and realized in this work. The addition of longer-wavelength channels sensitive at lower temperatures highly expands the measured temperature range, which covers the temperature of interest in shock physics from 1500K-10000K. The working wavelength range is 400-1700nm from visible light to near-infrared (NIR). Semiconductor detectors of Si and InGaAs are used as photoelectric devices, whose bandwidths are 50MHz and 150MHz respectively. Benefitting from the high responsivity and high speed of detectors, the time resolution of the pyrometer can be smaller than 10ns. By combining the high-transmittance beam-splitters and narrow-bandwidth filters, the peak spectrum transmissivity of each channel can be higher than 60%. The gray-body temperatures of NaI crystal under shock-loading are successfully measured by this pyrometer.

  7. Visible-Frequency Dielectric Metasurfaces for Multiwavelength Achromatic and Highly Dispersive Holograms.

    Science.gov (United States)

    Wang, Bo; Dong, Fengliang; Li, Qi-Tong; Yang, Dong; Sun, Chengwei; Chen, Jianjun; Song, Zhiwei; Xu, Lihua; Chu, Weiguo; Xiao, Yun-Feng; Gong, Qihuang; Li, Yan

    2016-08-10

    Dielectric metasurfaces built up with nanostructures of high refractive index represent a powerful platform for highly efficient flat optical devices due to their easy-tuning electromagnetic scattering properties and relatively high transmission efficiencies. Here we show visible-frequency silicon metasurfaces formed by three kinds of nanoblocks multiplexed in a subwavelength unit to constitute a metamolecule, which are capable of wavefront manipulation for red, green, and blue light simultaneously. Full phase control is achieved for each wavelength by independently changing the in-plane orientations of the corresponding nanoblocks to induce the required geometric phases. Achromatic and highly dispersive meta-holograms are fabricated to demonstrate the wavefront manipulation with high resolution. This technique could be viable for various practical holographic applications and flat achromatic devices.

  8. Scintillating fiber tracking at high luminosities using Visible Light Photon counter readout

    International Nuclear Information System (INIS)

    Atac, M.

    1995-11-01

    This paper reviews the research work on the Visible Light Photon Counters (VLPC) that have been developed for the scintillating fiber tracking at high luminosity colliders and high rate fixed target experiments. The devices originated from the joint work between UCLA and Rockwell International Science Center. The VLPCs are capable of counting photons very efficiently down to a single photon level with high avalanche gain, producing pulses at very high rates with very short rise times. Due to small gain dispersions they can be used in counting photons with high quantum efficiencies, therefore they are excellent devices for charged particle tracking using small diameter scintillating plastic fibers. In this paper, fiber tracking for the CDF and D0 upgrades and a possible usage of the VLPC readout for the experiment E803 at Fermilab will be discussed

  9. Broadband plasmonic silver nanoflowers for high-performance random lasing covering visible region

    Directory of Open Access Journals (Sweden)

    Chang Qing

    2017-05-01

    Full Text Available Multicolor random lasing has broad potential applications in the fields of imaging, sensing, and optoelectronics. Here, silver nanoflowers (Ag NF with abundant nanogaps are fabricated by a rapid one-step solution-phase synthesis method and are first proposed as effective broadband plasmonic scatterers to achieve different color random lasing. With abundant nanogaps and spiky tips near the surface and the interparticle coupling effect, Ag NFs greatly enhance the local electromagnetic field and induce broadband plasmonic scattering spectra over the whole visible range. The extremely low working threshold and the high-quality factor for Ag NF-based random lasers are thus demonstrated as 0.24 MW cm−2 and 11,851, respectively. Further, coherent colorful random lasing covering the visible range is realized using the dye molecules oxazine (red, Coumarin 440 (blue, and Coumarin 153 (green, showing high-quality factor of more than 10,000. All these features show that Ag NF are highly efficient scatterers for high-performance coherent random lasing and colorful random lasers.

  10. Graphene–Ag/ZnO nanocomposites as high performance photocatalysts under visible light irradiation

    International Nuclear Information System (INIS)

    Ahmad, M.; Ahmed, E.; Hong, Z.L.; Khalid, N.R.; Ahmed, W.; Elhissi, A.

    2013-01-01

    , great adsorption of dyes, enhanced visible light absorption and fast transfer processes. This research has the potential to provide new avenues for the in situ fabrication of the Graphene–Ag/ZnO composites as highly efficient photocatalysts

  11. Investigation of Self-injection Locked Visible Laser Diodes for High Bit-rate Visible Light Communication

    KAUST Repository

    Shamim, Md. Hosne Mobarok; Shemis, Mohamed; Shen, Chao; Oubei, Hassan M.; Ng, Tien Khee; Ooi, Boon S.; Khan, Mohammed Zahed Mustafa

    2018-01-01

    -mode-suppression-ratio was considerably increased in all the cases, reaching as high as ~20 dB in self-injection locked blue laser diode, thus enabling a close to single mode operation. This work paves the way for attaining high speed optical wireless communications by overcoming

  12. High security chaotic multiple access scheme for visible light communication systems with advanced encryption standard interleaving

    Science.gov (United States)

    Qiu, Junchao; Zhang, Lin; Li, Diyang; Liu, Xingcheng

    2016-06-01

    Chaotic sequences can be applied to realize multiple user access and improve the system security for a visible light communication (VLC) system. However, since the map patterns of chaotic sequences are usually well known, eavesdroppers can possibly derive the key parameters of chaotic sequences and subsequently retrieve the information. We design an advanced encryption standard (AES) interleaving aided multiple user access scheme to enhance the security of a chaotic code division multiple access-based visible light communication (C-CDMA-VLC) system. We propose to spread the information with chaotic sequences, and then the spread information is interleaved by an AES algorithm and transmitted over VLC channels. Since the computation complexity of performing inverse operations to deinterleave the information is high, the eavesdroppers in a high speed VLC system cannot retrieve the information in real time; thus, the system security will be enhanced. Moreover, we build a mathematical model for the AES-aided VLC system and derive the theoretical information leakage to analyze the system security. The simulations are performed over VLC channels, and the results demonstrate the effectiveness and high security of our presented AES interleaving aided chaotic CDMA-VLC system.

  13. Four High-Visibility Enforcement Demonstration Waves in Connecticut and New York Reduce Hand-Held Phone Use

    Science.gov (United States)

    2011-07-01

    The National Highway Traffic : Safety Administration initiated : distracted driving demonstration : programs in two communities : to test whether a high-visibility : enforcement (HVE) model could : reduce two specific instances : of distracted drivin...

  14. High power visible diode laser for the treatment of eye diseases by laser coagulation

    Science.gov (United States)

    Heinrich, Arne; Hagen, Clemens; Harlander, Maximilian; Nussbaumer, Bernhard

    2015-03-01

    We present a high power visible diode laser enabling a low-cost treatment of eye diseases by laser coagulation, including the two leading causes of blindness worldwide (diabetic retinopathy, age-related macular degeneration) as well as retinopathy of prematurely born children, intraocular tumors and retinal detachment. Laser coagulation requires the exposure of the eye to visible laser light and relies on the high absorption of the retina. The need for treatment is constantly increasing, due to the demographic trend, the increasing average life expectancy and medical care demand in developing countries. The World Health Organization reacts to this demand with global programs like the VISION 2020 "The right to sight" and the following Universal Eye Health within their Global Action Plan (2014-2019). One major point is to motivate companies and research institutes to make eye treatment cheaper and easily accessible. Therefore it becomes capital providing the ophthalmology market with cost competitive, simple and reliable technologies. Our laser is based on the direct second harmonic generation of the light emitted from a tapered laser diode and has already shown reliable optical performance. All components are produced in wafer scale processes and the resulting strong economy of scale results in a price competitive laser. In a broader perspective the technology behind our laser has a huge potential in non-medical applications like welding, cutting, marking and finally laser-illuminated projection.

  15. A high resolution IR/visible imaging system for the W7-X limiter

    International Nuclear Information System (INIS)

    Wurden, G. A.; Dunn, J. P.; Stephey, L. A.; Biedermann, C.; Jakubowski, M. W.; Gamradt, M.

    2016-01-01

    A high-resolution imaging system, consisting of megapixel mid-IR and visible cameras along the same line of sight, has been prepared for the new W7-X stellarator and was operated during Operational Period 1.1 to view one of the five inboard graphite limiters. The radial line of sight, through a large diameter (184 mm clear aperture) uncoated sapphire window, couples a direct viewing 1344 × 784 pixel FLIR SC8303HD camera. A germanium beam-splitter sends visible light to a 1024 × 1024 pixel Allied Vision Technologies Prosilica GX1050 color camera. Both achieve sub-millimeter resolution on the 161 mm wide, inertially cooled, segmented graphite tiles. The IR and visible cameras are controlled via optical fibers over full Camera Link and dual GigE Ethernet (2 Gbit/s data rates) interfaces, respectively. While they are mounted outside the cryostat at a distance of 3.2 m from the limiter, they are close to a large magnetic trim coil and require soft iron shielding. We have taken IR data at 125 Hz to 1.25 kHz frame rates and seen that surface temperature increases in excess of 350 °C, especially on leading edges or defect hot spots. The IR camera sees heat-load stripe patterns on the limiter and has been used to infer limiter power fluxes (∼1–4.5 MW/m"2), during the ECRH heating phase. IR images have also been used calorimetrically between shots to measure equilibrated bulk tile temperature, and hence tile energy inputs (in the range of 30 kJ/tile with 0.6 MW, 6 s heating pulses). Small UFO’s can be seen and tracked by the FLIR camera in some discharges. The calibrated visible color camera (100 Hz frame rate) has also been equipped with narrow band C-III and H-alpha filters, to compare with other diagnostics, and is used for absolute particle flux determination from the limiter surface. Sometimes, but not always, hot-spots in the IR are also seen to be bright in C-III light.

  16. A high resolution IR/visible imaging system for the W7-X limiter

    Energy Technology Data Exchange (ETDEWEB)

    Wurden, G. A., E-mail: wurden@lanl.gov; Dunn, J. P. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Stephey, L. A. [University of Wisconsin, Madison, Wisconsin 53706 (United States); Biedermann, C.; Jakubowski, M. W.; Gamradt, M. [Max Planck Institut für Plasma Physik, Wendelsteinstrasse 1, 17491 Greifswald (Germany)

    2016-11-15

    A high-resolution imaging system, consisting of megapixel mid-IR and visible cameras along the same line of sight, has been prepared for the new W7-X stellarator and was operated during Operational Period 1.1 to view one of the five inboard graphite limiters. The radial line of sight, through a large diameter (184 mm clear aperture) uncoated sapphire window, couples a direct viewing 1344 × 784 pixel FLIR SC8303HD camera. A germanium beam-splitter sends visible light to a 1024 × 1024 pixel Allied Vision Technologies Prosilica GX1050 color camera. Both achieve sub-millimeter resolution on the 161 mm wide, inertially cooled, segmented graphite tiles. The IR and visible cameras are controlled via optical fibers over full Camera Link and dual GigE Ethernet (2 Gbit/s data rates) interfaces, respectively. While they are mounted outside the cryostat at a distance of 3.2 m from the limiter, they are close to a large magnetic trim coil and require soft iron shielding. We have taken IR data at 125 Hz to 1.25 kHz frame rates and seen that surface temperature increases in excess of 350 °C, especially on leading edges or defect hot spots. The IR camera sees heat-load stripe patterns on the limiter and has been used to infer limiter power fluxes (∼1–4.5 MW/m{sup 2}), during the ECRH heating phase. IR images have also been used calorimetrically between shots to measure equilibrated bulk tile temperature, and hence tile energy inputs (in the range of 30 kJ/tile with 0.6 MW, 6 s heating pulses). Small UFO’s can be seen and tracked by the FLIR camera in some discharges. The calibrated visible color camera (100 Hz frame rate) has also been equipped with narrow band C-III and H-alpha filters, to compare with other diagnostics, and is used for absolute particle flux determination from the limiter surface. Sometimes, but not always, hot-spots in the IR are also seen to be bright in C-III light.

  17. High-power fiber-coupled 100W visible spectrum diode lasers for display applications

    Science.gov (United States)

    Unger, Andreas; Küster, Matthias; Köhler, Bernd; Biesenbach, Jens

    2013-02-01

    Diode lasers in the blue and red spectral range are the most promising light sources for upcoming high-brightness digital projectors in cinemas and large venue displays. They combine improved efficiency, longer lifetime and a greatly improved color space compared to traditional xenon light sources. In this paper we report on high-power visible diode laser sources to serve the demands of this emerging market. A unique electro-optical platform enables scalable fiber coupled sources at 638 nm with an output power of up to 100 W from a 400 μm NA0.22 fiber. For the blue diode laser we demonstrate scalable sources from 5 W to 100 W from a 400 μm NA0.22 fiber.

  18. Polymer dots grafted TiO2 nanohybrids as high performance visible light photocatalysts.

    Science.gov (United States)

    Li, Gen; Wang, Feng; Liu, Peng; Chen, Zheming; Lei, Ping; Xu, Zhongshan; Li, Zengxi; Ding, Yanfen; Zhang, Shimin; Yang, Mingshu

    2018-04-01

    As a new member of carbon dots (CDs), Polymer dots (PDs) prepared by hydrothermal treatment of polymers, usually consist of the carbon core and the connected partially degraded polymer chains. This type of CDs might possess aqueous solubility, non-toxicity, excellent stability against photo-bleaching and high visible light activity. In this research, PDs were prepared by a moderate hydrothermal treatment of polyvinyl alcohol, and PDs grafted TiO 2 (PDs-TiO 2 ) nanohybrids with TiOC bonds were prepared by a facile in-situ hydrothermal treatment of PDs and Ti (SO 4 ) 2 . Under visible light irradiation, the PDs-TiO 2 demonstrate excellent photocatalytic activity for methyl orange degradation, and the photocatalytic rate constant of PDs-TiO 2 is 3.6 and 9.5 times higher than that of pure TiO 2 and commercial P25, respectively. In addition, the PDs-TiO 2 exhibit good recycle stability under UV-Vis light irradiation. The interfacial TiOC bonds and the π-conjugated structures in PDs-TiO 2 can act as the pathways to quickly transfer the excited electrons between PDs and TiO 2 , therefore contribute to the excellent photocatalytic activity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  19. High-resolution UV-visible spectroscopy of lunar red spots

    Science.gov (United States)

    Bruno, B. C.; Lucey, P. G.; Hawke, B. R.

    1991-01-01

    A spectral reflectance study of selected lunar 'red spots', highland areas characterized by an absorption in the ultraviolet relative to the visible was conducted. Some red spots were suggested to be the sites of ancient highland volcanism. High-resolution spectral data of eight red spots on the western portion of the moon over the wavelength region 0.39-0.82 micron were obtained. Much spectral variation among these red spots in the magnitude as well as the wavelength position of the ultraviolet absorption were found. Spectral structure at visible and near-infrared wavelength were also identified. These spectral differences indicate that red spots do not have a single mineralogical composition, which in turn suggests that red spots may have multiple origins. Additional imaging spectroscopic observations were taken of the Herigonius red spot, a morphologically complex region northeast of Mare Humorum. These data reveal significant spectral differences among the various morphological units within the Herigonius red spot. Although some of these are likely due to the effects of the maturation process, others appear to reflect differences in mineral abundances and composition.

  20. Highly cited articles in wind tunnel-related research: a bibliometric analysis.

    Science.gov (United States)

    Mo, Ziwei; Fu, Hui-Zhen; Ho, Yuh-Shan

    2018-03-22

    Wind tunnels have been widely employed in aerodynamic research. To characterize the high impact research, a bibliometric analysis was conducted on highly cited articles related to wind tunnel based on the Science Citation Index Expanded (SCI-EXPANDED) database from 1900 to 2014. Articles with at least 100 citations from the Web of Science Core Collection were selected and analyzed in terms of publication years, authors, institutions, countries/territories, journals, Web of Science categories, and citation life cycles. The results show that a total of 77 highly cited articles in 37 journals were published between 1959 and 2008. Journal of Fluid Mechanics published the most of highly cited articles. The USA was the most productive country and most frequent partner of internationally collaboration. The prolific institutions were mainly located in the USA and UK. The authors who were both first author and corresponding author published 88% of the articles. The Y index was also deployed to evaluate the publication characteristics of authors. Moreover, the articles with high citations in both history and the latest year with their citation life cycles were examined to provide insights for high impact research. The highly cited articles were almost earliest wind tunnel experimental data and reports on their own research specialty, and thus attracted high citations. It was revealed that classic works of wind tunnel research was frequently occurred in 1990s but much less in 2000s, probably due to the development of numerical models of computational fluid dynamic (CFD) in recent decades.

  1. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication.

    Science.gov (United States)

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M; Oh, Sang Ho; Margalith, Tal; Speck, James S; Nakamura, Shuji; Bowers, John E; DenBaars, Steven P

    2015-06-15

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  2. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication

    KAUST Repository

    Lee, Changmin

    2015-06-10

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free-space data transmission rate was achieved at room temperature.

  3. 4 Gbps direct modulation of 450 nm GaN laser for high-speed visible light communication

    KAUST Repository

    Lee, Changmin; Zhang, Chong; Cantore, Michael; Farrell, Robert M.; Oh, Sang Ho; Margalith, Tal; Speck, James S.; Nakamura, Shuji; Bowers, John E.; DenBaars, Steven P.

    2015-01-01

    We demonstrate high-speed data transmission with a commercial high power GaN laser diode at 450 nm. 2.6 GHz bandwidth was achieved at an injection current of 500 mA using a high-speed visible light communication setup. Record high 4 Gbps free

  4. High-fidelity frequency down-conversion of visible entangled photon pairs with superconducting single-photon detectors

    International Nuclear Information System (INIS)

    Ikuta, Rikizo; Kato, Hiroshi; Kusaka, Yoshiaki; Yamamoto, Takashi; Imoto, Nobuyuki; Miki, Shigehito; Yamashita, Taro; Terai, Hirotaka; Wang, Zhen; Fujiwara, Mikio; Sasaki, Masahide; Koashi, Masato

    2014-01-01

    We experimentally demonstrate a high-fidelity visible-to-telecommunicationwavelength conversion of a photon by using a solid-state-based difference frequency generation. In the experiment, one half of a pico-second visible entangled photon pair at 780 nm is converted to a 1522-nm photon. Using superconducting single-photon detectors with low dark count rates and small timing jitters, we observed a fidelity of 0.93±0.04 after the wavelength conversion

  5. ELLERMAN BOMBS AT HIGH RESOLUTION. IV. VISIBILITY IN Na I AND Mg I

    Energy Technology Data Exchange (ETDEWEB)

    Rutten, R. J.; Rouppe van der Voort, L. H. M.; Vissers, G. J. M., E-mail: R.J.Rutten@uu.nl [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, N-0315 Oslo (Norway)

    2015-08-01

    Ellerman bombs are transient brightenings of the wings of the solar Balmer lines that mark reconnection in the photosphere. Ellerman noted in 1917 that he did not observe such brightenings in the Na i D and Mg i b lines. This non-visibility should constrain EB interpretation, but has not been addressed in published bomb modeling. We therefore test Ellerman’s observation and confirm it using high-quality imaging spectrometry with the Swedish 1-m Solar Telescope. However, we find a diffuse brightness in these lines that seems to result from prior EBs. We tentatively suggest this is a post-bomb hot-cloud phenomenon also found in recent EB spectroscopy in the ultraviolet.

  6. Quantum dots/silica/polymer nanocomposite films with high visible light transmission and UV shielding properties.

    Science.gov (United States)

    Mumin, Md Abdul; Xu, William Z; Charpentier, Paul A

    2015-08-07

    The dispersion of light-absorbing inorganic nanomaterials in transparent plastics such as poly(ethylene-co-vinyl acetate) (PEVA) is of enormous current interest in emerging solar materials, including photovoltaic (PV) modules and commercial greenhouse films. Nanocrystalline semiconductor or quantum dots (QDs) have the potential to absorb UV light and selectively emit visible light, which can control plant growth in greenhouses or enhance PV panel efficiencies. This work provides a new and simple approach for loading mesoporous silica-encapsulated QDs into PEVA. Highly luminescent CdS and CdS-ZnS core-shell QDs with 5 nm size were synthesized using a modified facile approach based on pyrolysis of the single-molecule precursors and capping the CdS QDs with a thin layer of ZnS. To make both the bare and core-shell structure QDs more resistant against photochemical reactions, a mesoporous silica layer was grown on the QDs through a reverse microemulsion technique based on hydrophobic interactions. By careful experimental tuning, this encapsulation technique enhanced the quantum yield (∼65%) and photostability compared to the bare QDs. Both the encapsulated bare and core-shell QDs were then melt-mixed with EVA pellets using a mini twin-screw extruder and pressed into thin films with controlled thickness. The results demonstrated for the first time that mesoporous silica not only enhanced the quantum yield and photostability of the QDs but also improved the compatibility and dispersibility of QDs throughout the PEVA films. The novel light selective films show high visible light transmission (∼90%) and decreased UV transmission (∼75%).

  7. Unattended real-time re-establishment of visibility in high dynamic range video and stills

    Science.gov (United States)

    Abidi, B.

    2014-05-01

    We describe a portable unattended persistent surveillance system that corrects for harsh illumination conditions, where bright sun light creates mixed contrast effects, i.e., heavy shadows and washouts. These effects result in high dynamic range scenes, where illuminance can vary from few luxes to a 6 figure value. When using regular monitors and cameras, such wide span of illuminations can only be visualized if the actual range of values is compressed, leading to the creation of saturated and/or dark noisy areas and a loss of information in these areas. Images containing extreme mixed contrast cannot be fully enhanced from a single exposure, simply because all information is not present in the original data. The active intervention in the acquisition process is required. A software package, capable of integrating multiple types of COTS and custom cameras, ranging from Unmanned Aerial Systems (UAS) data links to digital single-lens reflex cameras (DSLR), is described. Hardware and software are integrated via a novel smart data acquisition algorithm, which communicates to the camera the parameters that would maximize information content in the final processed scene. A fusion mechanism is then applied to the smartly acquired data, resulting in an enhanced scene where information in both dark and bright areas is revealed. Multi-threading and parallel processing are exploited to produce automatic real time full motion corrected video. A novel enhancement algorithm was also devised to process data from legacy and non-controllable cameras. The software accepts and processes pre-recorded sequences and stills, enhances visible, night vision, and Infrared data, and successfully applies to night time and dark scenes. Various user options are available, integrating custom functionalities of the application into intuitive and easy to use graphical interfaces. The ensuing increase in visibility in surveillance video and intelligence imagery will expand the performance and

  8. Biomimetic fabrication of WO3 for water splitting under visible light with high performance

    International Nuclear Information System (INIS)

    Yin, Chao; Zhu, Shenmin; Yao, Fan; Gu, Jiajun; Zhang, Wang; Chen, Zhixin; Zhang, Di

    2013-01-01

    Inspired by the high light-harvesting properties of typical butterfly wings, ceramic WO 3 butterfly wings with hierarchical structures of bio-butterfly wings was fabricated using a template of PapilioParis butterfly wings through a sol–gel method. The effect of calcination temperatures on the structures of the ceramic butterfly wings was investigated and the results showed that the WO 3 butterfly wing replica calcined at 550 °C (WO 3 replica-550) is a single phase and has a high crystallinity and relatively fine hierarchical structure. The average grain size of WO 3 replica-550 and WO 3 powder are around 32.6 and 42.2 nm, respectively. Compared with pure WO 3 powder, WO 3 replica-550 demonstrated a higher light-harvesting capability in the region from 460 to 700 nm and more importantly the higher charge separation rate, as evidenced by electron paramagnetic resonance measurements. Photocatalytic O 2 evolutions from water were investigated on the ceramic butterfly wings and pure WO 3 powder under visible light (λ > 420 nm). The results showed that the amount of O 2 produced from WO 3 replica-550 is 50 % higher than that of the pure WO 3 powder. The improved photocatalytic performance of WO 3 replica-550 is attributed to the quasi-honeycomb structure inherited from the PapilioParis butterfly wings, providing both high light-harvesting efficiency and efficient charge transport through the WO 3

  9. Highly cited works in radiology: the top 100 cited articles in radiologic journals.

    Science.gov (United States)

    Pagni, Matthew; Khan, Nickalus R; Cohen, Harris L; Choudhri, Asim F

    2014-08-01

    The number of citations a publication receives can be used to show its impact on a field of study. It may indicate the educational interest in a given population or underline a perceived or real educational gap. This article identifies and characterizes the 100 top cited publications in radiologic journals as of May 2013. All clinical radiologic journals listed by Thomson Reuters Journal Citation Reports in 2011 were identified. A total of 46 journals were identified, and all articles published within these journals were analyzed for citation counts. The top 100 highly cited articles were recorded. The most frequently cited radiologic articles appeared in 9 of the 46 journals. These included 59 articles in Radiology, 17 in Journal of Nuclear Medicine, 9 in the American Journal of Roentgenology, 5 in the British Journal of Radiology, 4 in Investigative Radiology, 2 in American Journal of Neuroradiology, 2 in European Radiology, 2 in Radiologic Clinics of North America, 1 in the Seminars in Nuclear Medicine, and 1 in Pediatric Radiology. The citation values ranged from 422 to 7506 with a mean of 751. Publication dates ranged from 1967 to 2006 with the 5-year period between 1986 and 1990 accounting for the largest percentage of articles. The most frequently studied radiologic modality was magnetic resonance imaging (MRI; 28 articles), followed by vascular/interventional (19 articles) and nuclear medicine (13 articles). The central nervous system was the most frequently studied organ system (22 articles), followed by mixed organ systems (14 articles) and liver (12 articles). The top cited articles in radiologic journals span a wide range of imaging modalities, subspecialties, and organ systems. Topics that occurred frequently in the top 100 cited articles included contrast and radiopharmaceutical characterization, MRI of motion, percutaneous radiofrequency ablation in the liver and percutaneous vertebroplasty. We present a methodology that uses citation analysis to

  10. Use of a Machine-learning Method for Predicting Highly Cited Articles Within General Radiology Journals.

    Science.gov (United States)

    Rosenkrantz, Andrew B; Doshi, Ankur M; Ginocchio, Luke A; Aphinyanaphongs, Yindalon

    2016-12-01

    This study aimed to assess the performance of a text classification machine-learning model in predicting highly cited articles within the recent radiological literature and to identify the model's most influential article features. We downloaded from PubMed the title, abstract, and medical subject heading terms for 10,065 articles published in 25 general radiology journals in 2012 and 2013. Three machine-learning models were applied to predict the top 10% of included articles in terms of the number of citations to the article in 2014 (reflecting the 2-year time window in conventional impact factor calculations). The model having the highest area under the curve was selected to derive a list of article features (words) predicting high citation volume, which was iteratively reduced to identify the smallest possible core feature list maintaining predictive power. Overall themes were qualitatively assigned to the core features. The regularized logistic regression (Bayesian binary regression) model had highest performance, achieving an area under the curve of 0.814 in predicting articles in the top 10% of citation volume. We reduced the initial 14,083 features to 210 features that maintain predictivity. These features corresponded with topics relating to various imaging techniques (eg, diffusion-weighted magnetic resonance imaging, hyperpolarized magnetic resonance imaging, dual-energy computed tomography, computed tomography reconstruction algorithms, tomosynthesis, elastography, and computer-aided diagnosis), particular pathologies (prostate cancer; thyroid nodules; hepatic adenoma, hepatocellular carcinoma, non-alcoholic fatty liver disease), and other topics (radiation dose, electroporation, education, general oncology, gadolinium, statistics). Machine learning can be successfully applied to create specific feature-based models for predicting articles likely to achieve high influence within the radiological literature. Copyright © 2016 The Association of University

  11. Multifunctional polyoxometalates encapsulated in MIL-100(Fe): highly efficient photocatalysts for selective transformation under visible light.

    Science.gov (United States)

    Liang, Ruowen; Chen, Rui; Jing, Fenfen; Qin, Na; Wu, Ling

    2015-11-07

    H3PMo12O40 molecules have been successfully encapsulated in the cavities of MIL-100(Fe) via a facile hydrothermal method (denoted as HPMo@MIL-100(Fe)). A series of characterization has corroborated the insertion of H3PMo12O40 within the cavities of MIL-100(Fe). The resulting HPMo@MIL-100(Fe) nanocomposites have exhibited much higher photoactivity than the original-MIL-100(Fe) toward the photocatalytic selective oxidation of benzylic alcohols and the reduction of Cr(vi) under visible light irradiation (λ≥ 420 nm). The higher photoactivity of HPMo@MIL-100(Fe) can be attributed to the integrative effect of enhanced light absorption intensity and more efficient separation of photogenerated electron-hole pairs. The host porous structure of MIL-100(Fe) can achieve a uniform composition with H3PMo12O40, which is significantly important for producing highly reactive dispersed H3PMo12O40 molecules and enhancing the photocatalytic activity of HPMo@MIL-100(Fe) nanocomposites. And the immobilized H3PMo12O40 molecules are more convenient for recycling. Importantly, almost no Fe and Mo ions leach from the MIL-100(Fe) during the reaction, which verifies the photostability of the HPMo@MIL-100(Fe). In addition, possible photocatalytic redox reaction mechanisms have been investigated.

  12. High speed visible light communication using blue GaN laser diodes

    Science.gov (United States)

    Watson, S.; Viola, S.; Giuliano, G.; Najda, S. P.; Perlin, P.; Suski, T.; Marona, L.; Leszczyński, M.; Wisniewski, P.; Czernecki, R.; Targowski, G.; Watson, M. A.; White, H.; Rowe, D.; Laycock, L.; Kelly, A. E.

    2016-10-01

    GaN-based laser diodes have been developed over the last 20 years making them desirable for many security and defence applications, in particular, free space laser communications. Unlike their LED counterparts, laser diodes are not limited by their carrier lifetime which makes them attractive for high speed communication, whether in free space, through fiber or underwater. Gigabit data transmission can be achieved in free space by modulating the visible light from the laser with a pseudo-random bit sequence (PRBS), with recent results approaching 5 Gbit/s error free data transmission. By exploiting the low-loss in the blue part of the spectrum through water, data transmission experiments have also been conducted to show rates of 2.5 Gbit/s underwater. Different water types have been tested to monitor the effect of scattering and to see how this affects the overall transmission rate and distance. This is of great interest for communication with unmanned underwater vehicles (UUV) as the current method using acoustics is much slower and vulnerable to interception. These types of laser diodes can typically reach 50-100 mW of power which increases the length at which the data can be transmitted. This distance could be further improved by making use of high power laser arrays. Highly uniform GaN substrates with low defectivity allow individually addressable laser bars to be fabricated. This could ultimately increase optical power levels to 4 W for a 20-emitter array. Overall, the development of GaN laser diodes will play an important part in free space optical communications and will be vital in the advancement of security and defence applications.

  13. Biomimetic fabrication of WO{sub 3} for water splitting under visible light with high performance

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Chao; Zhu, Shenmin, E-mail: smzhu@sjtu.edu.cn; Yao, Fan; Gu, Jiajun; Zhang, Wang [Shanghai Jiao Tong University, State Key Laboratory of Metal Matrix Composites (China); Chen, Zhixin [University of Wollongong, Faculty of Engineering (Australia); Zhang, Di, E-mail: zhangdi@sjtu.edu.cn [Shanghai Jiao Tong University, State Key Laboratory of Metal Matrix Composites (China)

    2013-08-15

    Inspired by the high light-harvesting properties of typical butterfly wings, ceramic WO{sub 3} butterfly wings with hierarchical structures of bio-butterfly wings was fabricated using a template of PapilioParis butterfly wings through a sol-gel method. The effect of calcination temperatures on the structures of the ceramic butterfly wings was investigated and the results showed that the WO{sub 3} butterfly wing replica calcined at 550 Degree-Sign C (WO{sub 3} replica-550) is a single phase and has a high crystallinity and relatively fine hierarchical structure. The average grain size of WO{sub 3} replica-550 and WO{sub 3} powder are around 32.6 and 42.2 nm, respectively. Compared with pure WO{sub 3} powder, WO{sub 3} replica-550 demonstrated a higher light-harvesting capability in the region from 460 to 700 nm and more importantly the higher charge separation rate, as evidenced by electron paramagnetic resonance measurements. Photocatalytic O{sub 2} evolutions from water were investigated on the ceramic butterfly wings and pure WO{sub 3} powder under visible light ({lambda} > 420 nm). The results showed that the amount of O{sub 2} produced from WO{sub 3} replica-550 is 50 % higher than that of the pure WO{sub 3} powder. The improved photocatalytic performance of WO{sub 3} replica-550 is attributed to the quasi-honeycomb structure inherited from the PapilioParis butterfly wings, providing both high light-harvesting efficiency and efficient charge transport through the WO{sub 3}.

  14. Visibility and Citation Impact

    Science.gov (United States)

    Ebrahim, Nader Ale; Salehi, Hadi; Embi, Mohamed Amin; Tanha, Farid Habibi; Gholizadeh, Hossein; Motahar, Seyed Mohammad

    2014-01-01

    The number of publications is the first criteria for assessing a researcher output. However, the main measurement for author productivity is the number of citations, and citations are typically related to the paper's visibility. In this paper, the relationship between article visibility and the number of citations is investigated. A case study of…

  15. Leading Contributors to the Research Consortium's Annual Program, 1992-2011: High-Visibility Institutions, Researchers, and Topics

    Science.gov (United States)

    Cardinal, Bradley J.; Lee, Hyo

    2013-01-01

    Between 1992-2011, peer-reviewed research on the Research Consortium's annual program has been published in abstract form in the "Research Quarterly for Exercise and Sport". On the basis of frequency, high-visibility institutions, researchers, and sub-disciplinary categories were identified. Data were extracted from each abstract (N =…

  16. Correlated relativistic dynamics and nuclear effects in dielectronic and visible spectra of highly charged ions

    International Nuclear Information System (INIS)

    Harman, Z.; Artemyev, A.N.; Crespo Lopez-Urrutia, J.R.

    2008-01-01

    Dielectronic recombination and visible emission spectra are investigated theoretically and experimentally. Spectra of x-rays emitted from electron beam ion trap plasmas allow the study of correlation and quantum electrodynamic effects in relativistic few-body systems. In the visible range, exploring the forbidden M1 transitions in Be- and B-like argon ions provides one new insights into the relativistic modelling of isotope shift effects and extend the scope of bound-electron g factor measurements to few-electron ions. (author)

  17. Liquid phase deposition of WO3/TiO2 heterojunction films with high photoelectrocatalytic activity under visible light irradiation

    International Nuclear Information System (INIS)

    Zhang, Man; Yang, Changzhu; Pu, Wenhong; Tan, Yuanbin; Yang, Kun; Zhang, Jingdong

    2014-01-01

    Highlights: • Liquid phase deposition is developed for preparing WO 3 /TiO 2 heterojunction films. • TiO 2 film provides an excellent platform for WO 3 deposition. • WO 3 expands the absorption band edge of TiO 2 film to visible light region. • WO 3 /TiO 2 heterojunction film shows high photoelectrocatalytic activity. - ABSTRACT: The heterojunction films of WO 3 /TiO 2 were prepared by liquid phase deposition (LPD) method via two-step processes. The scanning electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopic analysis indicated that flower-like WO 3 film was successfully deposited on TiO 2 film with the LPD processes. The TiO 2 film provided an excellent platform for WO 3 deposition while WO 3 obviously expanded the absorption of TiO 2 film to visible light. As the result, the heterojunction film of WO 3 /TiO 2 exhibited higher photocurrent response to visible light illumination than pure TiO 2 or WO 3 film. The photoelectrocatalytic (PEC) activity of WO 3 /TiO 2 film was evaluated by degrading Rhodamin B (RhB) and 4-chlorophenol (4-CP) under visible light irradiation. The results showed that the LPD WO 3 /TiO 2 film possessed high PEC activity for efficient removal of various refractory organic pollutants

  18. General approach to high power, coherent visible and ultraviolet light sources

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer

    by cascaded second harmonic and sum frequency generation using periodically poled KTP and BBO for the SHG and SFG process, respectively. The 355nm light is used to promote different photo induced reactions. The main limitation of reaching any desired wavelength in the visible spectrum using sum frequency...

  19. Ultraporous Electron-Depleted ZnO Nanoparticle Networks for Highly Sensitive Portable Visible-Blind UV Photodetectors.

    Science.gov (United States)

    Nasiri, Noushin; Bo, Renheng; Wang, Fan; Fu, Lan; Tricoli, Antonio

    2015-08-05

    A hierarchical nano- and microstructured morphology for visible-blind UV photo-detectors is developed, which provides record-high milliampere photocurrents, nanoampere dark currents, and excellent selectivity to ultralow UV light intensities. This is a significant step toward the integration of high-performance UV photodetectors in wearable devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Facile Synthesis of Monodispersed Polysulfide Spheres for Building Structural Colors with High Color Visibility and Broad Viewing Angle.

    Science.gov (United States)

    Li, Feihu; Tang, Bingtao; Wu, Suli; Zhang, Shufen

    2017-01-01

    The synthesis and assembly of monodispersed colloidal spheres are currently the subject of extensive investigation to fabricate artificial structural color materials. However, artificial structural colors from general colloidal crystals still suffer from the low color visibility and strong viewing angle dependence which seriously hinder their practical application in paints, colorimetric sensors, and color displays. Herein, monodispersed polysulfide (PSF) spheres with intrinsic high refractive index (as high as 1.858) and light-absorbing characteristics are designed, synthesized through a facile polycondensation and crosslinking process between sodium disulfide and 1,2,3-trichloropropane. Owing to their high monodispersity, sufficient surface charge, and good dispersion stability, the PSF spheres can be assembled into large-scale and high-quality 3D photonic crystals. More importantly, high structural color visibility and broad viewing angle are easily achieved because the unique features of PSF can remarkably enhance the relative reflectivity and eliminate the disturbance of scattering and background light. The results of this study provide a simple and efficient strategy to create structural colors with high color visibility, which is very important for their practical application. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Electrolytes for high voltage electrochemical double layer capacitors: A perspective article

    Science.gov (United States)

    Balducci, A.

    2016-09-01

    The development of innovative electrolyte components is nowadays considered one of the most important aspects for the realization of high energy electrochemical double capacitors (EDLCs). Consequently, in the last years many investigations have been dedicated towards new solvents, new salts and ionic liquids able to replace the current electrolytes. This perspective article aims to supply a critical analysis about the results obtained so far on the development of new electrolytes for high energy EDLCs and to outline the advantages as well as the limits related to the use of these innovative components. Furthermore, this article aims to give indications about the strategies could be used in the future for a further development of advanced electrolytes.

  2. High Performance self-injection locked 524 nm green laser diode for high bitrate visible light communications

    KAUST Repository

    Shamim, Md. Hosne Mobarok; Shemis, Mohamed; Shen, Chao; Oubei, Hassan M.; Ng, Tien Khee; Ooi, Boon S.; Khan, Mohammed Zahed Mustafa

    2018-01-01

    First demonstration of self-injection locking on 524 nm visible laser diode is presented. Enhancement by ~440 MHz (~30%) in modulation bandwidth, ~7 times reduction in lasing linewidth, and ~10 dB improvement in SMSR is achieved.

  3. High Performance self-injection locked 524 nm green laser diode for high bitrate visible light communications

    KAUST Repository

    Shamim, Md. Hosne Mobarok

    2018-03-05

    First demonstration of self-injection locking on 524 nm visible laser diode is presented. Enhancement by ~440 MHz (~30%) in modulation bandwidth, ~7 times reduction in lasing linewidth, and ~10 dB improvement in SMSR is achieved.

  4. Organic-inorganic hybrid optical foils with strong visible reflection, excellent near infrared-shielding ability and high transparency

    Science.gov (United States)

    Zhou, Yijie; Huang, Aibin; Zhou, Huaijuan; Ji, Shidong; Jin, Ping

    2018-03-01

    Research on functional flexible films has recently been attracting widespread attention especially with regards to foils, which can be designed artificially on the basis of the practical requirements. In this work, a foil with high visible reflection and a strong near infrared shielding efficiency was prepared by a simple wet chemical method. In the process of making this kind of optical foil, emulsion polymerization was first introduced to synthesize polymer opals, which were further compressed between two pieces of polyethylene terephthalate (PET) foil under polymer melting temperature to obtain a photonic crystal film with a strong reflection in the visible region to block blue rays. The following step was to coat a layer of the inorganic nano paint, which was synthesized by dispersing Cs-doped WO3 (CWO) nanoparticles homogenously into organic resin on the surface of the PET to achieve a high near infrared shielding ability. The final composite foil exhibited unique optical properties such as high visible reflectance (23.9%) to block blue rays, and excellent near infrared shielding efficiency (98.0%), meanwhile it still maintained a high transparency meaning that this foil could potentially be applied in energy-saving window films. To sum up, this study provides new insight into devising flexible hybrid films with novel optical properties, which could be further extended to prepare other optical films for potential use in automobile, architectural and other decorative fields.

  5. Evaluation of a high visibility enforcement project focused on passenger vehicles interacting with commercial vehicles.

    Science.gov (United States)

    Thomas, F Dennis; Blomberg, Richard D; Peck, Raymond C; Cosgrove, Linda A; Salzberg, Philip M

    2008-01-01

    In 2004, Washington State applied NHTSA's High Visibility Enforcement model used in the Click It or Ticket seat belt campaign in an attempt to reduce unsafe driving behaviors around commercial motor vehicles (CMVs). The program was called Ticketing Aggressive Cars and Trucks (TACT). This paper details the methods used to evaluate the program's effectiveness and the results of the evaluation. Four high-crash interstate highway corridors, each approximately 25 miles in length, were selected. Two of these corridors received TACT media messages and increased enforcement over an 18-month period while two comparison corridors did not receive any increased media or enforcement. A total of 4,737 contacts were made with drivers during the two enforcement waves, and 72% of these contacts led to a citation. Drivers at the intervention sites who said they saw or heard any of the TACT messages increased from 17.7% in the pre period to a high of 67.3% in the post periods. Drivers at the intervention sites also reported increased exposure to the core message of leaving more space when passing trucks (14% pre to 40% post period). The percentage of drivers who said they leave more room when passing trucks than when passing cars rose from 16% in the pre period to 24% in the post period at the intervention sites, while comparison sites showed no change. Over 150 hours of video recorded by law enforcement officers in unmarked vehicles were utilized to examine violation rates and severity of violations before and after the intervention campaigns. Statistical analyses showed that violation rates were reduced significantly at the intervention sites (between 23% and 46%), while remaining constant at the comparison sites. Analyses of the video data also showed that the seriousness of the residual violations at the intervention sites decreased. Overall, the evaluation results provide a consistent picture of the effectiveness of the TACT pilot project. Success was demonstrated at every step

  6. High Throughput, High Yield Fabrication of High Quantum Efficiency Back-Illuminated Photon Counting, Far UV, UV, and Visible Detector Arrays

    Science.gov (United States)

    Nikzad, Shouleh; Hoenk, M. E.; Carver, A. G.; Jones, T. J.; Greer, F.; Hamden, E.; Goodsall, T.

    2013-01-01

    In this paper we discuss the high throughput end-to-end post fabrication processing of high performance delta-doped and superlattice-doped silicon imagers for UV, visible, and NIR applications. As an example, we present our results on far ultraviolet and ultraviolet quantum efficiency (QE) in a photon counting, detector array. We have improved the QE by nearly an order of magnitude over microchannel plates (MCPs) that are the state-of-the-art UV detectors for many NASA space missions as well as defense applications. These achievements are made possible by precision interface band engineering of Molecular Beam Epitaxy (MBE) and Atomic Layer Deposition (ALD).

  7. Using cuttlefish ink as an additive to produce -non-iridescent structural colors of high color visibility.

    Science.gov (United States)

    Zhang, Yafeng; Dong, Biqin; Chen, Ang; Liu, Xiaohan; Shi, Lei; Zi, Jian

    2015-08-26

    Non-iridescent structural colors of high color visibility are produced by amorphous photonic structures, in which -natural cuttlefish ink is used as an additive to break down the long-range order of the structures. The color hue and its spectral purity can be tuned by adjusting the diameter of the polystyrene (PS) spheres and the proportion of ink particles. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Carbon-doped SnS2 nanostructure as a high-efficiency solar fuel catalyst under visible light.

    Science.gov (United States)

    Shown, Indrajit; Samireddi, Satyanarayana; Chang, Yu-Chung; Putikam, Raghunath; Chang, Po-Han; Sabbah, Amr; Fu, Fang-Yu; Chen, Wei-Fu; Wu, Chih-I; Yu, Tsyr-Yan; Chung, Po-Wen; Lin, M C; Chen, Li-Chyong; Chen, Kuei-Hsien

    2018-01-12

    Photocatalytic formation of hydrocarbons using solar energy via artificial photosynthesis is a highly desirable renewable-energy source for replacing conventional fossil fuels. Using an L-cysteine-based hydrothermal process, here we synthesize a carbon-doped SnS 2 (SnS 2 -C) metal dichalcogenide nanostructure, which exhibits a highly active and selective photocatalytic conversion of CO 2 to hydrocarbons under visible-light. The interstitial carbon doping induced microstrain in the SnS 2 lattice, resulting in different photophysical properties as compared with undoped SnS 2 . This SnS 2 -C photocatalyst significantly enhances the CO 2 reduction activity under visible light, attaining a photochemical quantum efficiency of above 0.7%. The SnS 2 -C photocatalyst represents an important contribution towards high quantum efficiency artificial photosynthesis based on gas phase photocatalytic CO 2 reduction under visible light, where the in situ carbon-doped SnS 2 nanostructure improves the stability and the light harvesting and charge separation efficiency, and significantly enhances the photocatalytic activity.

  9. High-contrast visible nulling coronagraph for segmented and arbitrary telescope apertures

    Science.gov (United States)

    Hicks, Brian A.; Lyon, Richard G.; Bolcar, Matthew R.; Clampin, Mark; Petrone, Peter

    2014-08-01

    Exoplanet coronagraphy will be driven by the telescope architectures available and thus the system designer must have available one or more suitable coronagraphic instrument choices that spans the set of telescope apertures, including filled (off-axis), obscured (e.g. with secondary mirror spiders and struts), segmented apertures, such as JWST, and interferometric apertures. In this work we present one such choice of coronagraph, known as the visible nulling coronagraph (VNC), that spans all four types of aperture and also employs differential sensing and control.

  10. A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks

    International Nuclear Information System (INIS)

    Wang, Zongjie; Parker, Benjamin; Samanipour, Roya; Kim, Keekyoung; Abdulla, Raafa; Ghosh, Sanjoy

    2015-01-01

    Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning. (paper)

  11. Three-dimensional high-precision indoor positioning strategy using Tabu search based on visible light communication

    Science.gov (United States)

    Peng, Qi; Guan, Weipeng; Wu, Yuxiang; Cai, Ye; Xie, Canyu; Wang, Pengfei

    2018-01-01

    This paper proposes a three-dimensional (3-D) high-precision indoor positioning strategy using Tabu search based on visible light communication. Tabu search is a powerful global optimization algorithm, and the 3-D indoor positioning can be transformed into an optimal solution problem. Therefore, in the 3-D indoor positioning, the optimal receiver coordinate can be obtained by the Tabu search algorithm. For all we know, this is the first time the Tabu search algorithm is applied to visible light positioning. Each light-emitting diode (LED) in the system broadcasts a unique identity (ID) and transmits the ID information. When the receiver detects optical signals with ID information from different LEDs, using the global optimization of the Tabu search algorithm, the 3-D high-precision indoor positioning can be realized when the fitness value meets certain conditions. Simulation results show that the average positioning error is 0.79 cm, and the maximum error is 5.88 cm. The extended experiment of trajectory tracking also shows that 95.05% positioning errors are below 1.428 cm. It can be concluded from the data that the 3-D indoor positioning based on the Tabu search algorithm achieves the requirements of centimeter level indoor positioning. The algorithm used in indoor positioning is very effective and practical and is superior to other existing methods for visible light indoor positioning.

  12. A simple and high-resolution stereolithography-based 3D bioprinting system using visible light crosslinkable bioinks.

    Science.gov (United States)

    Wang, Zongjie; Abdulla, Raafa; Parker, Benjamin; Samanipour, Roya; Ghosh, Sanjoy; Kim, Keekyoung

    2015-12-22

    Bioprinting is a rapidly developing technique for biofabrication. Because of its high resolution and the ability to print living cells, bioprinting has been widely used in artificial tissue and organ generation as well as microscale living cell deposition. In this paper, we present a low-cost stereolithography-based bioprinting system that uses visible light crosslinkable bioinks. This low-cost stereolithography system was built around a commercial projector with a simple water filter to prevent harmful infrared radiation from the projector. The visible light crosslinking was achieved by using a mixture of polyethylene glycol diacrylate (PEGDA) and gelatin methacrylate (GelMA) hydrogel with eosin Y based photoinitiator. Three different concentrations of hydrogel mixtures (10% PEG, 5% PEG + 5% GelMA, and 2.5% PEG + 7.5% GelMA, all w/v) were studied with the presented systems. The mechanical properties and microstructure of the developed bioink were measured and discussed in detail. Several cell-free hydrogel patterns were generated to demonstrate the resolution of the solution. Experimental results with NIH 3T3 fibroblast cells show that this system can produce a highly vertical 3D structure with 50 μm resolution and 85% cell viability for at least five days. The developed system provides a low-cost visible light stereolithography solution and has the potential to be widely used in tissue engineering and bioengineering for microscale cell patterning.

  13. High photoactive and visible-light responsive graphene/titanate nanotubes photocatalysts: preparation and characterization.

    Science.gov (United States)

    Qianqian, Zhai; Tang, Bo; Guoxin, Hu

    2011-12-30

    A series of graphene/titanate nanotubes (TNTs) photocatalysts using graphene and nanoscale TiO(2) or P25 as original materials were fabricated by hydrothermal method. Both low hydrothermal temperature and proper amount of graphene are propitious to better photoactivity. The photocatalytic activities of these nanocomposites far exceed that of P25, pure TNTs and reported TiO(2)-based nanocomposites for the degradation of Rhodamine-B under visible-light irradiation. These prepared photocatalysts were characterized by TEM, XRD, XPS, BET, FTIR and UV-vis diffuse reflection spectra, and the results indicate that the outstanding photoactivities in visible-light region result from sensitization effect of graphene rather than impurity level in the band gap of TNTs. Furthermore, large BET surface areas of these photocatalysts (almost 10 times larger than that of previously reported graphene/TiO(2) nanoparticles) evidently enhance their absorption abilities and photocatalytic performances (the rate constants of degrading Rhodamine-B are at least 5 times higher than that of previously reported photocatalysts). These photocatalysts show good stability, and their photoactivities do not obviously decrease after four times of repeated uses. A detailed photocatalytic mechanism is suggested, as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Nano-ferrites for water splitting: Unprecedented high photocatalytic hydrogen production under visible light

    KAUST Repository

    Mangrulkar, Priti A.; Polshettiwar, Vivek; Labhsetwar, Nitin K.; Varma, Rajender S.; Rayalu, Sadhana Suresh

    2012-01-01

    In the present investigation, hydrogen production via water splitting by nano-ferrites was studied using ethanol as the sacrificial donor and Pt as co-catalyst. Nano-ferrite is emerging as a promising photocatalyst with a hydrogen evolution rate of 8.275 μmol h -1 and a hydrogen yield of 8275 μmol h -1 g -1 under visible light compared to 0.0046 μmol h -1 for commercial iron oxide (tested under similar experimental conditions). Nano-ferrites were tested in three different photoreactor configurations. The rate of hydrogen evolution by nano-ferrite was significantly influenced by the photoreactor configuration. Altering the reactor configuration led to sevenfold (59.55 μmol h -1) increase in the hydrogen evolution rate. Nano-ferrites have shown remarkable stability in hydrogen production up to 30 h and the cumulative hydrogen evolution rate was observed to be 98.79 μmol h -1. The hydrogen yield was seen to be influenced by several factors like photocatalyst dose, illumination intensity, irradiation time, sacrificial donor and presence of co-catalyst. These were then investigated in detail. It was evident from the experimental data that nano-ferrites under optimized reaction conditions and photoreactor configuration could lead to remarkable hydrogen evolution activity under visible light. Temperature had a significant role in enhancing the hydrogen yield. © 2012 The Royal Society of Chemistry.

  15. Visible and NIR spectral band combination to produce high security ID tags for automatic identification

    Science.gov (United States)

    Pérez-Cabré, Elisabet; Millán, María S.; Javidi, Bahram

    2006-09-01

    Verification of a piece of information and/or authentication of a given object or person are common operations carried out by automatic security systems that can be applied, for instance, to control the entrance to restricted areas, access to public buildings, identification of cardholders, etc. Vulnerability of such security systems may depend on the ease of counterfeiting the information used as a piece of identification for verification and authentication. To protect data against tampering, the signature that identifies an object is usually encrypted to avoid an easy recognition at human sight and an easy reproduction using conventional devices for imaging or scanning. To make counterfeiting even more difficult, we propose to combine data from visible and near infrared (NIR) spectral bands. By doing this, neither the visible content nor the NIR data by theirselves are sufficient to allow the signature recognition and thus, the identification of a given object. Only the appropriate combination of both signals permits a satisfactory authentication. In addition, the resulting signature is encrypted following a fully-phase encryption technique and the obtained complex-amplitude distribution is encoded on an ID tag. Spatial multiplexing of the encrypted signature allows us to build a distortion-invariant ID tag, so that remote authentication can be achieved even if the tag is captured under rotation or at different distances. We also explore the possibility of using partial information of the encrypted signature to simplify the ID tag design.

  16. Cut-off scaling of high-harmonic generation driven by a femtosecond visible optical parametric amplifier

    International Nuclear Information System (INIS)

    Cirmi, Giovanni; Lai, Chien-Jen; Granados, Eduardo; Huang, Shu-Wei; Sell, Alexander; Hong, Kyung-Han; Moses, Jeffrey; Keathley, Phillip; Kärtner, Franz X

    2012-01-01

    We studied high-harmonic generation (HHG) in Ar, Ne and He gas jets using a broadly tunable, high-energy optical parametric amplifier (OPA) in the visible wavelength range. We optimized the noncollinear OPA to deliver tunable, femtosecond pulses with 200-500 µJ energy at the 1 kHz repetition rate with excellent spatiotemporal properties, suitable for HHG experiments. By tuning the central wavelength of the OPA while keeping other parameters (energy, duration and beam size) constant, we experimentally studied the scaling law of cut-off energy with the driver wavelength in helium. Our measurements show a λ 1.7+0.2 dependence of the HHG cut-off photon energy over the full visible range in agreement with previous experiments of near- and mid-IR wavelengths. By tuning the central wavelength of the driver source, the high-order harmonic spectra in the extreme ultraviolet cover the full range of photon energy between ∼25 and ∼100 eV. Due to the high coherence intrinsic in HHG, as well as the broad and continuous tunability in the extreme UV range, a high energy, high repetition rate version of this source might be an ideal seed for free electron lasers.

  17. News from the Library: Publishing Open Access articles beyond High Energy Physics

    CERN Multimedia

    CERN Library

    2012-01-01

    CERN has supported Open Access Publishing for many years, and the Scientific Information Service is working to implement this vision. We have just launched the flagship project SCOAP3 (Sponsoring Consortium for Open Access Publishing in Particle Physics) aimed at converting high-quality journals in High Energy Physics to Open Access for articles published as of 2014. More details here.   In parallel, several win-win arrangements allow experimental and theoretical high-energy physics results from CERN to be published in Open Access in a variety of high-impact journals. More information can be found here. Open Access publishing at CERN goes far beyond High Energy Physics. Indeed, CERN is a key supporter of Open Access in accelerator science, through sponsorship of the APS journal PRSTAB and participation in the JACoW collaboration. Now CERN authors publishing in the field of engineering will also have th...

  18. CdS nanoparticles/CeO_2 nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    International Nuclear Information System (INIS)

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue

    2016-01-01

    Graphical abstract: Coupling CdS with CeO_2 can effectively improve the light-harvesting ability of wide-band gap CeO_2 NRs as the photoinduced electrons on the conduction band of CdS are transfered to the conduction band of CeO_2. - Highlights: • Coupling CdS can effectively improve the light-harvesting ability of wide-band gap CeO_2. • CdS/CeO_2 composites show high photocatalytic activity under visible light irradiation. • The mechanism of photocatalytic H_2 evolution over CdS/CeO_2 was proposed. - Abstract: Different mole ratios of CdS nanoparticles (NPs)/CeO_2 nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H_2 production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO_2 NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H_2-production rate of 8.4 mmol h"−"1 g"−"1 under visible-light irradiation (λ > 420 nm). The superior photocatalytic H_2 evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO_2 NRs, which can effectively extend the light absorption range of wide-band gap CeO_2 NRs. This work provides feasible routes to develop visible-light responsive CeO_2-based nanomaterial for efficient solar utilization.

  19. Prevalence of high-grade squamous intraepithelial lesions and cervical cancer among patients with unsatisfactory colposcopic examination, without visible lesion

    Directory of Open Access Journals (Sweden)

    Fernanda Rangel da Veiga

    Full Text Available CONTEXT AND OBJECTIVE: Cervical cancer is a serious public health problem in Brazil. For patients with unsatisfactory colposcopic examinations without visible lesions, but with cervical cytological tests suggesting high-grade squamous intraepithelial lesion (HSIL, the national recommendation is to repeat cervical cytological tests after three months. Our aim was to assess the prevalence of HSIL and cancer among patients with initial cervical cytological tests suggestive of HSIL but with unsatisfactory colposcopic examinations without visible lesions, in order to contribute towards the discussion regarding a more effective clinical approach that might diminish the likelihood of patient abandonment of follow-up before appropriate diagnosis and treatment. DESIGN AND SETTING: Cross-sectional study in Colposcopy Clinic of IFF/Fiocruz. METHOD: Patients admitted between December 1989 and April 2007 with cytological diagnoses of HSIL but with unsatisfactory colposcopic examinations without visible lesions underwent cervical cone biopsy. RESULTS: Sixty-five such patients were included, comprising 33.8% with HSIL and 4.6% with cancer, confirmed histologically. The other patients presented low-grade squamous intraepithelial lesion (26.1%, glandular dysplasia (1.5% and absence of disease (33.8%. CONCLUSION: The observed prevalence of cancer and HSIL does not seem to be enough to justify immediate referral for cone biopsies to investigate the cervical canal in these cases. The findings suggest that the recommendation of repeated cytological tests following an initial one with HSIL, among patients with unsatisfactory colposcopic examinations without visible lesions, is appropriate in our setting. Efforts are needed to ensure adherence to follow-up protocols in order to reduce the chances of losses.

  20. Synthesis of Bismuth Stannate Nanoparticles with High Photocatalytic Activity under the Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    G. Gnanamoorthy

    2017-06-01

    Full Text Available Malachite Green is one of the most important organic dye, it contains triphenylmethane groups and it has been widely used for many industries. The hazardous dyes were rapidly act on immune and reproductive systems with carcinogenic effect of human health. Different methods were used for the hazardous removal in various industries, such as photocatalysis, biological treatment and adsorption process. The bismuth stannate nanoparticles have special properties of the hydrogen storage, biomolecule detection, gas sensors and catalysis. The bismuth stannate nanoparticles can be used for the degradation of organic pollutants and bismuth stannate is an important ternary oxide semiconductor with a wide band gap material. The composites were synthesized by a hydrothermal method, the obtained product was characterized by XRD, Raman, the morphology structure was confirmed by scanning electron microscopy and optical properties were carried out by DRS-UV-Vis spectroscopy. The excellent photocatalytic performance of the catalyst was evaluated by malachite green under the visible light.

  1. High spatial and temporal resolution visible spectroscopy of the plasma edge in DIII-D

    International Nuclear Information System (INIS)

    Gohil, P.; Burrell, K.H.; Groebner, R.J.; Seraydarian, R.P.

    1990-10-01

    In DIII-D, visible spectroscopic measurements of the He II 468.6 nm and C VI 529.2 nm Doppler broadened spectral lines, resulting from charge exchange recombination interactions between beam neutral atoms and plasma ions, are performed to determine ion temperatures, and toroidal and poloidal rotation velocities. The diagnostics system comprises 32 viewing chords spanning a typical minor radius of 63 cm across the midplane, of which 16 spatial chords span 11 cm of the plasma edge just within the separatrix. A temporal resolution of 260 μs per time slice can be obtained as a result of using MCP phosphors with short decay times and fast camera readout electronics. Results from this system will be used in radial electric field comparisons with theory at the L-H transition and ion transport analysis. 6 refs., 3 figs

  2. Highly Efficient and Visible Light Responsive Heterojunction Composites as Dual Photoelectrodes for Photocatalytic Fuel Cell

    Directory of Open Access Journals (Sweden)

    Honghui Pan

    2018-01-01

    Full Text Available In the present work, a novel photocatalytic fuel cell (PFC system involving a dual heterojunction photoelectrodes, viz. polyaniline/TiO2 nanotubes (PANI/TiO2 NTs photoanode and CuO/Co3O4 nanorods (CuO/Co3O4 NRs photocathode, has been designed. Compared to TiO2 NTs electrode of PFC, the present heterojunction design not only enhances the visible light absorption but also offers the higher efficiency in degrading Rhodamine B–a model organic pollutant. The study includes an evaluation of the dual performance of the photoelectrodes as well. Under visible-light irradiation of 3 mW cm−2, the cell composed of the photoanode PANI/TiO2 NTs and CuO/Co3O4 NRs photocathode forms an interior bias of +0.24 V within the PFC system. This interior bias facilitated the transfer of electrons from the photoanode to photocathode across the external circuit and combined with the holes generated therein along with a simultaneous power production. In this manner, the separation of electron/hole pair was achieved in the photoelectrodes by releasing the holes and electrons of PANI/TiO2 NTs photoanode and CuO/Co3O4 NRs photocathode, respectively. Using this PFC system, the degradation of Rhodamine B in aqueous media was achieved to an extent of 68.5% within a reaction duration of a four-hour period besides a simultaneous power generation of 85 μA cm−2.

  3. High-frequency collocations of nouns in research articles across eight disciplines

    Directory of Open Access Journals (Sweden)

    Matthew Peacock

    2012-04-01

    Full Text Available This paper describes a corpus-based analysis of the distribution of the high-frequency collocates of abstract nouns in 320 research articles across eight disciplines: Chemistry, Computer Science, Materials Science, Neuroscience, Economics, Language and Linguistics, Management, and Psychology. Disciplinary variation was also examined – very little previous research seems to have investigated this. The corpus was analysed using WordSmith Tools. The 16 highest-frequency nouns across all eight disciplines were identified, followed by the highest-frequency collocates for each noun. Five disciplines showed over 50% variance from the overall results. Conclusions are that the differing patterns revealed are disciplinary norms and represent standard terminology within the disciplines arising from the topics discussed, research methods, and content of discussions. It is also concluded that the collocations are an important part of the meanings and functions of the nouns, and that this evidence of sharp discipline differences underlines the importance of discipline-specific collocation research.

  4. Making Intercultural Language Learning Visible and Assessable

    Science.gov (United States)

    Moloney, Robyn; Harbon, Lesley

    2010-01-01

    While languages education (Liddicoat, 2002) is being transformed by intercultural language learning theory, there is little illustration of either how students are achieving intercultural learning or how to assess it. This article reports on a study of high school language students in Sydney, Australia. Its findings make visible student…

  5. Ductile long range ordered alloys with high critical ordering temperature and wrought articles fabricated therefrom

    Science.gov (United States)

    Liu, Chain T.; Inouye, Henry

    1979-01-01

    Malleable long range ordered alloys having high critical ordering temperatures exist in the V(Fe, Co).sub.3 and V(Fe, Co, Ni).sub.3 systems. These alloys have the following compositions comprising by weight: 22-23% V, 14-30% Fe, and the remainder Co or Co and Ni with an electron density no more than 7.85. The maximum combination of high temperature strength, ductility and creep resistance are manifested in the alloy comprising by weight 22-23% V, 14-20% Fe and the remainder Co and having an atomic composition of V(Fe .sub.0.20-0.26 C Co.sub.0.74-0.80).sub.3. The alloy comprising by weight 22-23% V, 16-17% Fe and 60-62% Co has excellent high temperature properties. The alloys are fabricable into wrought articles by casting, deforming, and annealing for sufficient time to provide ordered structure.

  6. Top 50 Highly Cited Articles on Dual Energy Computed Tomography (DECT) in Abdominal Radiology: A Bibliometric Analysis

    Science.gov (United States)

    Gong, Bo; Wu, Yuhao; O’Keeffe, Michael E; Berger, Ferco H; McLaughlin, Patrick D; Nicolaou, Savvas

    2017-01-01

    Summary This study aims to identify the 50 most highly cited articles on dual energy computed tomography (DECT) in abdominal radiology Thomson Reuters Web of Science All Databases was queried without year or language restriction. Only original research articles with a primary focus on abdominal radiology using DECT were selected. Review articles, meta-analyses, and studies without human subjects were excluded. Fifty articles with the highest average yearly citation were identified. These articles were published between 2007 and 2017 in 12 journals, with the most in Radiology (12 articles). Articles had a median of 7 authors, with all first authors but one primarily affiliated to radiology departments. The United States of America produced the most articles (16), followed by Germany (13 articles), and China (7 articles). Most studies used Dual Source DECT technology (35 articles), followed by Rapid Kilovoltage Switching (14 articles), and Sequential Scanning (1 article). The top three scanned organs were the liver (24%), kidney (16%), and urinary tract (15%). The most commonly studied pathology was urinary calculi (28%), renal lesion/tumor (23%), and hepatic lesion/tumor (20%). Our study identifies intellectual milestones in the applications of DECT in abdominal radiology. The diversity of the articles reflects on the characteristics and quality of the most influential publications related to DECT. PMID:29657641

  7. Highly efficient photocatalytic hydrogen evolution from nickel quinolinethiolate complexes under visible light irradiation

    Science.gov (United States)

    Rao, Heng; Yu, Wen-Qian; Zheng, Hui-Qin; Bonin, Julien; Fan, Yao-Ting; Hou, Hong-Wei

    2016-08-01

    Earth-abundant metal complexes have emerged as promising surrogates of platinum for catalyzing the hydrogen evolution reaction (HER). In this study, we report the design and synthesis of two novel nickel quinolinethiolate complexes, namely [Ni(Hqt)2(4, 4‧-Z-2, 2‧-bpy)] (Hqt = 8-quinolinethiol, Z = sbnd H [1] or sbnd CH3 [2], bpy = bipyridine). An efficient three-component photocatalytic homogeneous system for hydrogen generation working under visible light irradiation was constructed by using the target complexes as catalysts, triethylamine (TEA) as sacrificial electron donor and xanthene dyes as photosensitizer. We obtain turnover numbers (TON, vs. catalyst) for H2 evolution of 5923/7634 under the optimal conditions with 5.0 × 10-6 M complex 1/2 respectively, 1.0 × 10-3 M fluorescein and 5% (v/v) TEA at pH 12.3 in EtOH/H2O (1:1, v/v) mixture after 8 h irradiation (λ > 420 nm). We discuss the mechanism of H2 evolution in the homogeneous photocatalytic system based on fluorescence spectrum and cyclic voltammetry data.

  8. Visible-blind and solar-blind detection induced by defects in AlGaN high electron mobility transistors

    Science.gov (United States)

    Armstrong, Andrew M.; Klein, Brianna; Allerman, Andrew A.; Douglas, Erica A.; Baca, Albert G.; Crawford, Mary H.; Pickrell, Greg W.; Sanchez, Carlos A.

    2018-03-01

    Visible- and solar-blind detection was demonstrated using Al0.45Ga0.55N/Al0.30Ga0.70N and Al0.85Ga0.25N/Al0.70Ga0.30N high electron mobility transistors (HEMTs), respectively. Peak responsivities (S) of 3.9 × 106 A/W in the saturation mode and 6.2 × 104 A/W in the pinch-off mode were observed for the visible-blind Al0.45Ga0.55N/Al0.30Ga0.70N HEMT, and a peak S of 4.9 × 104 A/W was observed for the solar-blind Al0.85Ga0.15N/Al0.70Ga0.30N HEMT in the saturation mode. Spectrally resolved photocurrent investigation indicated that sub-bandgap absorption by defect states was the primary origin of the HEMTs' photoresponse. Defect-mediated responsivity caused slow photocurrent rise and fall times, but electrical pulsing was used to improve the bandwidth at the cost of optical gain. Operating HEMTs in this dynamic mode achieved a 25 Hz bandwidth with S = 2.9 × 105 A/W in accumulation and S = 2.0 × 104 A/W in pinch-off for visible-blind detection and S = 5.1 × 103 A/W for solar-blind detection.

  9. High-Performance Visible-Blind Ultraviolet Photodetector Based on IGZO TFT Coupled with p-n Heterojunction.

    Science.gov (United States)

    Yu, Jingjing; Javaid, Kashif; Liang, Lingyan; Wu, Weihua; Liang, Yu; Song, Anran; Zhang, Hongliang; Shi, Wen; Chang, Ting-Chang; Cao, Hongtao

    2018-03-07

    A visible-blind ultraviolet (UV) photodetector was designed based on a three-terminal electronic device of thin-film transistor (TFT) coupled with two-terminal p-n junction optoelectronic device, in hope of combining the beauties of both of the devices together. Upon the uncovered back-channel surface of amorphous indium-gallium-zinc-oxide (IGZO) TFT, we fabricated PEDOT:PSS/SnO x /IGZO heterojunction structure, through which the formation of a p-n junction and directional carrier transfer of photogenerated carriers were experimentally validated. As expected, the photoresponse characteristics of the newly designed photodetector, with a photoresponsivity of 984 A/W at a wavelength of 320 nm, a UV-visible rejection ratio up to 3.5 × 10 7 , and a specific detectivity up to 3.3 × 10 14 Jones, are not only competitive compared to the previous reports but also better than those of the pristine IGZO phototransistor. The hybrid photodetector could be operated in the off-current region with low supply voltages (<0.1 V) and ultralow power dissipation (<10 nW under illumination and ∼0.2 pW in the dark). Moreover, by applying a short positive gate pulse onto the gate, the annoying persistent photoconductivity presented in the wide band gap oxide-based devices could be suppressed conveniently, in hope of improving the response rate. With the terrific photoresponsivity along with the advantages of photodetecting pixel integration, the proposed phototransistor could be potentially used in high-performance visible-blind UV photodetector pixel arrays.

  10. Digital/Commercial (In)visibility

    DEFF Research Database (Denmark)

    Leander, Anna

    2017-01-01

    an argument demonstrating specifically how digital and commercial logics characterize the aesthetic, circulatory, and infrastructuring practices re-producing the regime of (in)visibility. It shows that digital/commercial logics are at the heart of the combinatorial marketing of multiple, contradictory images......This article explores one aspect of digital politics, the politics of videos and more spe- cifically of DAESH recruitment videos. It proposes a practice theoretical approach to the politics of DAESH recruitment videos focused on the re-production of regimes of (in)visibility. The article develops...... on the internet. The theoretical and political cost of overlooking these digital and commercial characteristics of DAESH visibility practices are high. It perpetuates misconceptions of how the videos work and what their politics are and it reinforces the digital Orientalism/Occidentalism in which...

  11. Three-dimensional nano-heterojunction networks: a highly performing structure for fast visible-blind UV photodetectors.

    Science.gov (United States)

    Nasiri, Noushin; Bo, Renheng; Fu, Lan; Tricoli, Antonio

    2017-02-02

    Visible-blind ultraviolet photodetectors are a promising emerging technology for the development of wide bandgap optoelectronic devices with greatly reduced power consumption and size requirements. A standing challenge is to improve the slow response time of these nanostructured devices. Here, we present a three-dimensional nanoscale heterojunction architecture for fast-responsive visible-blind UV photodetectors. The device layout consists of p-type NiO clusters densely packed on the surface of an ultraporous network of electron-depleted n-type ZnO nanoparticles. This 3D structure can detect very low UV light densities while operating with a near-zero power consumption of ca. 4 × 10 -11 watts and a low bias of 0.2 mV. Most notably, heterojunction formation decreases the device rise and decay times by 26 and 20 times, respectively. These drastic enhancements in photoresponse dynamics are attributed to the stronger surface band bending and improved electron-hole separation of the nanoscale NiO/ZnO interface. These findings demonstrate a superior structural design and a simple, low-cost CMOS-compatible process for the engineering of high-performance wearable photodetectors.

  12. BiVO4–graphene catalyst and its high photocatalytic performance under visible light irradiation

    International Nuclear Information System (INIS)

    Fu Yongsheng; Sun Xiaoqiang; Wang Xin

    2011-01-01

    Highlights: ► A facile strategy is designed to deposit leaf-like BiVO 4 lamellas on graphene sheet. ► Graphene oxide is reduced to graphene in the hydrothermal reaction process. ► BiVO 4 –graphene system shows high catalytic effects under visible light irradiation. - Abstract: A BiVO 4 –graphene photocatalyst was prepared by a facile one-step hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectra (XPS), and transmission electron microscopy (TEM) techniques. The results show that the graphene sheets in this catalyst are exfoliated and decorated by leaf-like BiVO 4 lamellas. In comparison with the pure BiVO 4 catalyst, the BiVO 4 –graphene system reveals much higher photocatalytic activity for degradation of methyl orange (MO), methylene blue (MB), Rhodamine B (RhB) and active black BL-G in water under visible light irradiation due to the concerted effects of BiVO 4 and graphene sheets or their integrated properties.

  13. Graphene supported silver@silver chloride & ferroferric oxide hybrid, a magnetically separable photocatalyst with high performance under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Suting; Jiang, Wei, E-mail: superfine_jw@126.com; Han, Mei; Liu, Gongzong; Zhang, Na; Lu, Yue

    2015-08-30

    Graphical abstract: - Highlights: • The composites were synthesized via a facile and effective process. • Plenty of Fe{sub 3}O{sub 4} and Ag@AgCl nanoparticles are deposited on the reduced graphene oxide nanosheets. • The catalyst exhibited an enhanced photocatalytic performance and magnetic property. • The catalyst is stable under the visible light irradiation. - Abstract: A stable magnetic separable plasmonic photocatalyst was successfully fabricated by grafting silver@silver chloride (Ag@AgCl) and ferroferric oxide (Fe{sub 3}O{sub 4}) nanoparticles on graphene sheets. The composite exhibited high activity degrading methylene blue (MB) and rhodamine B (RB) under visible light irradiation: decomposition 97.4% of MB in 100 min and 97.9% of RB in 120 min. The enhanced photocatalytic activities can be attributed to synergistic effect between Ag@AgCl and graphene: the effective charge transfer from Ag@AgCl to graphene thus promotes the separation of electron–hole pairs. Moreover, the excellent magnetic property gives a more convenient way to recycle the photocatalysts.

  14. Highly efficient tandem polymer solar cells with a photovoltaic response in the visible light range.

    Science.gov (United States)

    Zheng, Zhong; Zhang, Shaoqing; Zhang, Maojie; Zhao, Kang; Ye, Long; Chen, Yu; Yang, Bei; Hou, Jianhui

    2015-02-18

    Highly efficient polymer solar cells with a tandem structure are fabricated by using two excellent photovoltaic polymers and a highly transparent intermediate recombination layer. Power conversion -efficiencies over 10% can be realized with a photovoltaic response within 800 nm. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Low cost alternative of high speed visible light camera for tokamak experiments

    Czech Academy of Sciences Publication Activity Database

    Odstrčil, T.; Odstrčil, Michal; Grover, O.; Svoboda, V.; Ďuran, Ivan; Mlynář, Jan

    2012-01-01

    Roč. 83, č. 10 (2012), 10E505-10E505 ISSN 0034-6748. [Topical Conference High-Temperature Plasma Diagnostics/19./. Monterey, 06.05.2012-10.05.2012] Institutional research plan: CEZ:AV0Z20430508 Keywords : Plasma * tokamak * diagnostic * high speed camera * GOLEM Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.602, year: 2012 http://dx.doi.org/10.1063/1.4731003

  16. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. OCCUPATIONAL EXPOSURE OF. INTERNS TO BLOOD IN AN AREA. OF HIGH HIV SEROPREVALENCE. A S Karstaedt, L Pantanowitz. Objective. To determine the epidemiology of work-related exposure to blood among interns. Design. Interns were invited to complete anonymously a questionnaire ...

  17. Phosphorene Co-catalyst Advancing Highly Efficient Visible-Light Photocatalytic Hydrogen Production.

    Science.gov (United States)

    Ran, Jingrun; Zhu, Bicheng; Qiao, Shi-Zhang

    2017-08-21

    Transitional metals are widely used as co-catalysts boosting photocatalytic H 2 production. However, metal-based co-catalysts suffer from high cost, limited abundance and detrimental environment impact. To date, metal-free co-catalyst is rarely reported. Here we for the first time utilized density functional calculations to guide the application of phosphorene as a high-efficiency metal-free co-catalyst for CdS, Zn 0.8 Cd 0.2 S or ZnS. Particularly, phosphorene modified CdS shows a high apparent quantum yield of 34.7 % at 420 nm. This outstanding activity arises from the strong electronic coupling between phosphorene and CdS, as well as the favorable band structure, high charge mobility and massive active sites of phosphorene, supported by computations and advanced characterizations, for example, synchrotron-based X-ray absorption near edge spectroscopy. This work brings new opportunities to prepare highly-active, cheap and green photocatalysts. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Detector array for measurement of high-frequency fluctuations in visible and near-UV emission from tokamaks

    International Nuclear Information System (INIS)

    Hurwitz, P.D.; Hall, B.F.; Rowan, W.L.

    1992-01-01

    We developed an imaging detector to measure high-frequency fluctuations in visible and near-UV emission from tokamaks. The detector is intended for the study of plasma turbulence, mhd phenomena, and edge-localized modes. Particularly in the first two applications, it will complement existing techniques by providing higher spatial resolution as well as measurement capability in otherwise inaccessible regions of the plasma. The device consists of an optical system, a linear array of 32 photodiodes, and an amplifier for each photodiode. The amplifiers have a transimpedance gain of 10 5 --10 6 and the frequency response is flat to 100 kHz. Experience with this device has shown that optical imaging systems can be easily designed and tailored to a specific measurement because of the small size and close spacing of the individual light-sensitive elements. The device has been successfully tested on TEXT-U in measurements of H α fluctuations

  19. The effect of high-pass filters on the visibility of microcalcifications

    International Nuclear Information System (INIS)

    Lai, Y-M.

    2002-01-01

    Mammographic microcalcifications are significant in diagnosis, as they may indicate early stage malignancy. Thus mammographic screen-film combinations incorporate high contrast and spatial resolution in order to detect fine details. However, screen-film combinations, coupling different functions, can pose limitations. Images acquired in digital format provide a new way of using images, as image enhancement can be achieved by manipulation in the spatial domain without additional radiation exposure. Gold disks of differing diameters and thickness in the Nijmegan phantom were used to simulate microcalcifications. Microcalcification, as an image feature, is of high frequency components in the spatial domain. High-pass filters enable enhancement of microcalcification. Three high-pass filters were investigated to compare their efficacy. A phantom consisting of polystyrene granules embedded in a sodium iodide solution was used to simulate the breast tissue pattern. A composite radiographic image was produced by combining the phantom with a Nijmegen phantom, which was then digitised and processed. This was assessed by observer performance in locating the microcalcifications. Also, line profile image analysis was performed on digital mammograms with microcalcifications. The filter with a central weight of 9 and neighbouring pixels of -1 exhibited the greatest effectiveness in the enhancement of the microcalcification. Copyright (2002) Australian Institute of Radiography

  20. Development of high efficient visible light-driven N, S-codoped TiO2 nanowires photocatalysts

    International Nuclear Information System (INIS)

    Zhang, Yanlin; Liu, Peihong; Wu, Honghai

    2015-01-01

    Highlights: • A facile hydrothermal route to synthesize N, S-codoped TiO 2 nanowires. • The codoped TiO 2 nanowires have TiO 2 (B) and anatase phase. • The significant shift of the optical absorption edge toward the visible region. • The photocatalyst showed high photocatalytic activity for atrazine. - Abstract: One-dimensional (1D) nanowire material (especially nonmetal doped 1D nanowires) synthesized by a facile way is of great significance and greatly desired as it has higher charge carrier mobility and lower carrier recombination rate. N, S-codoped TiO 2 nanowires were synthesized using titanium sulfate as a precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, HRTEM, SAED, XPS, BET and UV–vis absorption spectrum. The incorporation of N and S into TiO 2 NWs can lead to the expansion of its lattice and remarkably lower its electron-transfer resistance. Photocatalytic activity measurement showed that the N, S-codoped TiO 2 nanowires with high quantum efficiency revealed the best photocatalytic performance for atrazine degradation under visible light irradiation compared to N, S-codoped TiO 2 nanoparticles and S-doped TiO 2 nanowires, which was attributed to (i) the synergistic effect of N and S doping in narrowing the band gap, separating electron–hole pairs and increasing the photoinduced electrons, and (ii) extending the anatase-to-rutile transformation temperature above 600 °C

  1. Development of high efficient visible light-driven N, S-codoped TiO{sub 2} nanowires photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanlin, E-mail: zhangyl@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Key Laboratory of Theoretical Chemistry of Environment Ministry of Education, South China Normal University, Guangzhou 510006 (China); Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Liu, Peihong; Wu, Honghai [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2015-02-15

    Highlights: • A facile hydrothermal route to synthesize N, S-codoped TiO{sub 2} nanowires. • The codoped TiO{sub 2} nanowires have TiO{sub 2} (B) and anatase phase. • The significant shift of the optical absorption edge toward the visible region. • The photocatalyst showed high photocatalytic activity for atrazine. - Abstract: One-dimensional (1D) nanowire material (especially nonmetal doped 1D nanowires) synthesized by a facile way is of great significance and greatly desired as it has higher charge carrier mobility and lower carrier recombination rate. N, S-codoped TiO{sub 2} nanowires were synthesized using titanium sulfate as a precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, HRTEM, SAED, XPS, BET and UV–vis absorption spectrum. The incorporation of N and S into TiO{sub 2} NWs can lead to the expansion of its lattice and remarkably lower its electron-transfer resistance. Photocatalytic activity measurement showed that the N, S-codoped TiO{sub 2} nanowires with high quantum efficiency revealed the best photocatalytic performance for atrazine degradation under visible light irradiation compared to N, S-codoped TiO{sub 2} nanoparticles and S-doped TiO{sub 2} nanowires, which was attributed to (i) the synergistic effect of N and S doping in narrowing the band gap, separating electron–hole pairs and increasing the photoinduced electrons, and (ii) extending the anatase-to-rutile transformation temperature above 600 °C.

  2. Astronomy at high angular resolution a compendium of techniques in the visible and near-infrared

    CERN Document Server

    Hussain, Gaitee; Berger, Jean-Philippe; Schmidtobreick, Linda

    2016-01-01

    This book offers an essential compendium of astronomical high-resolution techniques. Recent years have seen considerable developments in such techniques, which are critical to advances in many areas of astronomy. As reflected in the book, these techniques can be divided into direct methods, interferometry, and reconstruction methods, and can be applied to a huge variety of astrophysical systems, ranging from planets, single stars and binaries to active galactic nuclei, providing angular resolution in the micro- to tens of milliarcsecond scales. Written by experts in their fields, the chapters cover adaptive optics, aperture masking imaging, spectra disentangling, interferometry, lucky imaging, Roche tomography, imaging with interferometry, interferometry of AGN, AGN reverberation mapping, Doppler- and magnetic imaging of stellar surfaces, Doppler tomography, eclipse mapping, Stokes imaging, and stellar tomography. This book is intended to enable a next generation of astronomers to apply high-resolution techni...

  3. Development of a high-speed single-photon pixellated detector for visible wavelengths

    CERN Document Server

    Mac Raighne, Aaron; Mathot, Serge; McPhate, Jason; Vallerga, John; Jarron, Pierre; Brownlee, Colin; O’Shea, Val

    2009-01-01

    We present the development of a high-speed, single-photon counting, Hybrid Photo Detector (HPD). The HPD consists of a vacuum tube, containing the detector assembly, sealed with a transparent optical input window. Photons incident on the photocathode eject a photoelectron into a large electric field, which accelerates the incident electron onto a silicon detector. The silicon detector is bump bonded to a Medipix readout chip. This set-up allows for the detection and readout of low incident photon intensities at rates that are otherwise unattainable with current camera technology. Reported is the fabrication of the camera that brings together a range of sophisticated design and fabrication techniques and the expected theoretical imaging performance. Applications to cellular and molecular microscopy are also described in which single-photon-counting abilities at high frame rates are crucial

  4. Nourodevelopmental follow-up in high-risk infants: review article

    Directory of Open Access Journals (Sweden)

    Farin Soleimani

    2015-02-01

    Full Text Available Growing and developing are influenced by genetic, social and environmental factors and it's most important and initial phase step is formed of the early life of the fetus and infant. According to the world health organization, the incidence of preterm birth and low birth weight are increasing in most countries that most of it related to developing countries. Low birth weight (LBW and preterm birth are one the most important causes of death in the world and therefore are considered as one of the major health problems that can affect growing and developing so that it can threaten public health. Advances in medical technology in recent decades at intensive care unit, increased survival of premature infants and high-risk specialist care is needed, but failed, to reduce the complications of premature birth but it couldn’t reduce complications of preterm birth. There is also an increased recognition of the potential disconnect between perinatal outcomes and long-term outcomes. The administration of oxygen and postnatal steroids are prime examples of interventions that may have immediate positive effects but negative long-term effects. Many premature babies will be encounter with mobility problems, cognitive, neurosensory impairments, cerebral palsy, cognitive and language delays, neuromotor developmental delay, blindness and hearing loss, behavioral and psychosocial disorders, learning difficulties and dysfunction in scholastic performances in the future. These disadvantages appear to persist into adulthood and therefore have broad implications for society. Without a doubt, one of the tragedies of the world is people with physical or mental damage caused by premature birth, many of these disorders are not early diagnosed and the prediction of long term complications of infants discharged from the NICU is difficult. Although nourodevelopmental follow-up of these babies is a necessary part of the neonatal assessment but there is no standard process

  5. Highly Efficient Visible Colloidal Lead-Halide Perovskite Nanocrystal Light-Emitting Diodes

    Science.gov (United States)

    Yan, Fei; Xing, Jun; Xing, Guichuan; Quan, Lina; Tan, Swee Tiam; Zhao, Jiaxin; Su, Rui; Zhang, Lulu; Chen, Shi; Zhao, Yawen; Huan, Alfred; Sargent, Edward H.; Xiong, Qihua; Demir, Hilmi Volkan

    2018-05-01

    Lead-halide perovskites have been attracting attention for potential use in solid-state lighting. Following the footsteps of solar cells, the field of perovskite light-emitting diodes (PeLEDs) has been growing rapidly. Their application prospects in lighting, however, remain still uncertain due to a variety of shortcomings in device performance including their limited levels of luminous efficiency achievable thus far. Here we show high-efficiency PeLEDs based on colloidal perovskite nanocrystals (PeNCs) synthesized at room temperature possessing dominant first-order excitonic radiation (enabling a photoluminescence quantum yield of 71% in solid film), unlike in the case of bulk perovskites with slow electron-hole bimolecular radiative recombination (a second-order process). In these PeLEDs, by reaching charge balance in the recombination zone, we find that the Auger nonradiative recombination, with its significant role in emission quenching, is effectively suppressed in low driving current density range. In consequence, these devices reach a record high maximum external quantum efficiency of 12.9% reported to date and an unprecedentedly high power efficiency of 30.3 lm W-1 at luminance levels above 1000 cd m-2 as required for various applications. These findings suggest that, with feasible levels of device performance, the PeNCs hold great promise for their use in LED lighting and displays.

  6. BInGaN alloys nearly lattice-matched to GaN for high-power high-efficiency visible LEDs

    Science.gov (United States)

    Williams, Logan; Kioupakis, Emmanouil

    2017-11-01

    InGaN-based visible light-emitting diodes (LEDs) find commercial applications for solid-state lighting and displays, but lattice mismatch limits the thickness of InGaN quantum wells that can be grown on GaN with high crystalline quality. Since narrower wells operate at a higher carrier density for a given current density, they increase the fraction of carriers lost to Auger recombination and lower the efficiency. The incorporation of boron, a smaller group-III element, into InGaN alloys is a promising method to eliminate the lattice mismatch and realize high-power, high-efficiency visible LEDs with thick active regions. In this work, we apply predictive calculations based on hybrid density functional theory to investigate the thermodynamic, structural, and electronic properties of BInGaN alloys. Our results show that BInGaN alloys with a B:In ratio of 2:3 are better lattice matched to GaN compared to InGaN and, for indium fractions less than 0.2, nearly lattice matched. Deviations from Vegard's law appear as bowing of the in-plane lattice constant with respect to composition. Our thermodynamics calculations demonstrate that the solubility of boron is higher in InGaN than in pure GaN. Varying the Ga mole fraction while keeping the B:In ratio constant enables the adjustment of the (direct) gap in the 1.75-3.39 eV range, which covers the entire visible spectrum. Holes are strongly localized in non-bonded N 2p states caused by local bond planarization near boron atoms. Our results indicate that BInGaN alloys are promising for fabricating nitride heterostructures with thick active regions for high-power, high-efficiency LEDs.

  7. The High Visible Resolution (HVR) instrument of the spot ground observation satellite

    Science.gov (United States)

    Otrio, G.

    1980-01-01

    Two identical high resolution cameras, capable of attaining a track width of 116 km in an almost vertical line of sight from the two 60 km images of each instrument, will be carried on the initial mission of the space observation of Earth satellite (SPOT). Specifications for the instrument, including the telescope and CCD devices are summarized. The present status of development is described including the optical characteristics, structure and thermal control, detector assembly, electronic equipment, and calibration. SPOT mission objectives include the developments relating to soil use, the exploration of EART Earth resources, the discrimination of plant species, and cartography.

  8. AgI/Ag3PO4 hybrids with highly efficient visible-light driven photocatalytic activity

    International Nuclear Information System (INIS)

    Katsumata, Hideyuki; Hayashi, Takahiro; Taniguchi, Masanao; Suzuki, Tohru; Kaneco, Satoshi

    2015-01-01

    Highlights: • AgI/Ag 3 PO 4 hybrid was prepared via an in situ anion-exchange method. • AgI/Ag 3 PO 4 displays the excellent photocatalytic activity under visible light. • AgI/Ag 3 PO 4 readily transforms to be Ag@AgI/Ag 3 PO 4 system. • h + and O 2 ·− play the major role in the AO 7 decolorization over AgI/Ag 3 PO 4 . • The activity enhancement is ascribed to a Z-scheme system composed of Ag 3 PO 4 , Ag and AgI. - Abstract: Highly efficient visible-light-driven AgI/Ag 3 PO 4 hybrid photocatalysts with different mole ratios of AgI were prepared via an in situ anion-exchange method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectroscopy (DRS) and photoluminescence (PL) technique. Under visible light irradiation (>420 nm), the AgI/Ag 3 PO 4 photocatalysts displayed the higher photocatalytic activity than pure Ag 3 PO 4 and AgI for the decolorization of acid orange 7 (AO 7). Among the hybrid photocatalysts, AgI/Ag 3 PO 4 with 80% of AgI exhibited the highest photocatalytic activity for the decolorization of AO 7. X-ray photoelectron spectroscopy (XPS) results revealed that AgI/Ag 3 PO 4 readily transformed to be Ag@AgI/Ag 3 PO 4 system while the photocatalytic activity of AgI/Ag 3 PO 4 remained after 5 recycling runs. In addition, the quenching effects of different scavengers displayed that the reactive h + and O 2 ·− play the major role in the AO 7 decolorization. The photocatalytic activity enhancement of AgI/Ag 3 PO 4 hybrids can be ascribed to the efficient separation of electron–hole pairs through a Z-scheme system composed of Ag 3 PO 4 , Ag and AgI, in which Ag nanoparticles act as the charge separation center

  9. High Throughput Exposure Modeling of Semi-Volatile Chemicals in Articles of Commerce (SOT)

    Science.gov (United States)

    Chemical components of consumer products and articles of commerce such as carpet and clothing are key drivers of exposure in the near-field environment. These chemicals include semi-volatile organic compounds (SVOCs), some of which have been shown to alter endocrine functionality...

  10. A High-Fidelity Haze Removal Method Based on HOT for Visible Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Hou Jiang

    2016-10-01

    Full Text Available Spatially varying haze is a common feature of most satellite images currently used for land cover classification and mapping and can significantly affect image quality. In this paper, we present a high-fidelity haze removal method based on Haze Optimized Transformation (HOT, comprising of three steps: semi-automatic HOT transform, HOT perfection and percentile based dark object subtraction (DOS. Since digital numbers (DNs of band red and blue are highly correlated in clear sky, the R-squared criterion is utilized to search the relative clearest regions of the whole scene automatically. After HOT transform, spurious HOT responses are first masked out and filled by means of four-direction scan and dynamic interpolation, and then homomorphic filter is performed to compensate for loss of HOT of masked-out regions with large areas. To avoid patches and halo artifacts, a procedure called percentile DOS is implemented to eliminate the influence of haze. Scenes including various land cover types are selected to validate the proposed method, and a comparison analysis with HOT and Background Suppressed Haze Thickness Index (BSHTI is performed. Three quality assessment indicators are selected to evaluate the haze removed effect on image quality from different perspective and band profiles are utilized to analyze the spectral consistency. Experiment results verify the effectiveness of the proposed method for haze removal and the superiority of it in preserving the natural color of object itself, enhancing local contrast, and maintaining structural information of original image.

  11. The High-efficiency LED Driver for Visible Light Communication Applications.

    Science.gov (United States)

    Gong, Cihun-Siyong Alex; Lee, Yu-Chen; Lai, Jyun-Liang; Yu, Chueh-Hao; Huang, Li Ren; Yang, Chia-Yen

    2016-08-08

    This paper presents a LED driver for VLC. The main purpose is to solve the low data rate problem used to be in switching type LED driver. The GaN power device is proposed to replace the traditional silicon power device of switching LED driver for the purpose of increasing switching frequency of converter, thereby increasing the bandwidth of data transmission. To achieve high efficiency, the diode-connected GaN power transistor is utilized to replace the traditional ultrafast recovery diode used to be in switching type LED driver. This work has been experimentally evaluated on 350-mA output current. The results demonstrate that it supports the data of PWM dimming level encoded in the PPM scheme for VLC application. The experimental results also show that system's efficiency of 80.8% can be achieved at 1-Mb/s data rate.

  12. Sn doped TiO{sub 2} nanotube with oxygen vacancy for highly efficient visible light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jinliang; Xu, Xingtao [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China); Liu, Xinjuan [Institute of Coordination Bond Metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China); Yu, Caiyan; Yan, Dong; Sun, Zhuo [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China); Pan, Likun, E-mail: lkpan@phy.ecnu.edu.cn [Engineering Research Center for Nanophotonics & Advanced Instrument, Ministry of Education, Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, Department of Physics, East China Normal University, Shanghai 200062 (China)

    2016-09-15

    Sn doped TiO{sub 2} nanotube with oxygen vacancy (V{sub o}-Sn−TiO{sub 2}) was successfully synthesized via a facile hydrothermal process and subsequent annealing in nitrogen atmosphere. The morphology, structure and photocatalytic performance of V{sub o}-Sn−TiO{sub 2} in the degradation of nitrobenzene were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, UV–vis absorption spectroscopy, nitrogen adsorption-desorption and electrochemical impedance spectra, respectively. The inner diameter, outer diameter and specific surface area of V{sub o}-Sn−TiO{sub 2} are about 5 nm, 15 nm and 235.54 m{sup 2} g{sup −1}, respectively. The experimental results show that the V{sub o}-Sn−TiO{sub 2} exhibits excellent photocatalytic performance with a maximum degradation rate of 92% in 300 min for nitrobenzene and 94% in 100 min for Rhodamine B and corresponding mineralization rates of 68% and 70% under visible light irradiation. The improved photocatalytic performance is ascribed to the enhanced light absorption and specific surface area as well as the reduced electron-hole pair recombination with the presence of oxygen vacancy and Sn doping in the TiO{sub 2} nanotube. - Highlights: • Photocatalysis is an environmental-friendly technology for nitrobenzene removal. • Sn doped TiO{sub 2} nanotube with oxygen vacancy is fabricated for the first time. • It exhibits excellent photocatalytic performance in degradation of nitrobenzene. • A high degradation rate of 92% is achieved under visible light irradiation.

  13. ELLERMAN BOMBS AT HIGH RESOLUTION. II. TRIGGERING, VISIBILITY, AND EFFECT ON UPPER ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    Vissers, Gregal J. M.; Rouppe van der Voort, Luc H. M.; Rutten, Robert J., E-mail: g.j.m.vissers@astro.uio.no [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway)

    2013-09-01

    We use high-resolution imaging spectroscopy with the Swedish 1-m Solar Telescope (SST) to study the transient brightenings of the wings of the Balmer H{alpha} line in emerging active regions that are called Ellerman bombs. Simultaneous sampling of Ca II 8542 A with the SST confirms that most Ellerman bombs also occur in the wings of this line, but with markedly different morphology. Simultaneous images from the Solar Dynamics Observatory (SDO) show that Ellerman bombs are also detectable in the photospheric 1700 A continuum, again with differing morphology. They are also observable in 1600 A SDO images, but with much contamination from C IV emission in transition-region features. Simultaneous SST spectropolarimetry in Fe I 6301 A shows that Ellerman bombs occur at sites of strong-field magnetic flux cancellation between small bipolar strong-field patches that rapidly move together over the solar surface. Simultaneous SDO images in He II 304 A, Fe IX 171 A, and Fe XIV 211 A show no clear effect of the Ellerman bombs on the overlying transition region and corona. These results strengthen our earlier suggestion, based on H{alpha} morphology alone, that the Ellerman bomb phenomenon is a purely photospheric reconnection phenomenon.

  14. Process for producing silicon nitride based articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.; Buljan, S.T.; Neil, J.T.

    1991-09-10

    A process for producing a silicon nitride-based article of improved fracture toughness and strength is disclosed. The process involves densifying to at least 98% of theoretical density a mixture including (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12 m[sup 2]/g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. Optionally, the mixture may be blended with a binder and injection molded to form a green body, which then may be densified by, for example, hot isostatic pressing.

  15. Long-range high-speed visible light communication system over 100-m outdoor transmission utilizing receiver diversity technology

    Science.gov (United States)

    Wang, Yiguang; Huang, Xingxing; Shi, Jianyang; Wang, Yuan-quan; Chi, Nan

    2016-05-01

    Visible light communication (VLC) has no doubt become a promising candidate for future wireless communications due to the increasing trends in the usage of light-emitting diodes (LEDs). In addition to indoor high-speed wireless access and positioning applications, VLC usage in outdoor scenarios, such as vehicle networks and intelligent transportation systems, are also attracting significant interest. However, the complex outdoor environment and ambient noise are the key challenges for long-range high-speed VLC outdoor applications. To improve system performance and transmission distance, we propose to use receiver diversity technology in an outdoor VLC system. Maximal ratio combining-based receiver diversity technology is utilized in two receivers to achieve the maximal signal-to-noise ratio. A 400-Mb/s VLC transmission using a phosphor-based white LED and a 1-Gb/s wavelength division multiplexing VLC transmission using a red-green-blue LED are both successfully achieved over a 100-m outdoor distance with the bit error rate below the 7% forward error correction limit of 3.8×10-3. To the best of our knowledge, this is the highest data rate at 100-m outdoor VLC transmission ever achieved. The experimental results clearly prove the benefit and feasibility of receiver diversity technology for long-range high-speed outdoor VLC systems.

  16. Are the Most Highly Cited Articles the Ones that are the Most Downloaded? A Bibliometric Study of IRRODL

    Directory of Open Access Journals (Sweden)

    Raidell Avello Martínez

    2015-06-01

    Full Text Available Publication of research, innovation, challenges and successes is of critical importance to the evolution of more effective distance education programming. Publication in peer reviewed journal format is the most prestigious and the most widespread form of dissemination in education and most other disciplines, thus the importance of understanding what is published and its impact on both researchers and practitioners. In this article we identify and classify the leading articles in arguably the leading peer reviewed journals in this discipline. The journal The International Review of Research in Open and Distance Learning (IRRODL is a peer reviewed academic journal that has been published since 2000. The journal has published between 3 and 6 issues annually with between 50 and 111 research articles per volume. In order to assess the general and the particular impact of highly cited articles this work describes the main bibliometric indicators of the IRRODL journal and these are compared with the total galley views in all formats, PDF, HTML, EPUB and MP3, that IRRODL publishes. In addition to identifying characteristics of the most widely cited articles this research determines if there is a correlation between the articles most highly cited by other publishing researchers and the number of views, indicating interest from both practitioners and research communities. The results show a significant and positive relationship between the total number of citations and the number of views received by articles published in the journal, indicating the impact of the journal extends beyond active publishers to practitioner consumers.

  17. Highly efficient visible light TiO{sub 2} photocatalyst prepared by sol-gel method at temperatures lower than 300 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Wang Desong, E-mail: dswang06@126.com [School of Sciences, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China); Xiao Libin; Luo Qingzhi; Li Xueyan; An Jing [School of Sciences, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China); Duan Yandong [College of Chemical and Pharmaceutical Engineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018 (China)

    2011-08-15

    Graphical abstract: Display Omitted Highlights: {yields} Mesoporous anatase nano-TiO{sub 2} photocatalyst was synthesized by sol-gel method at lower temperature ({<=}300 {sup o}C). {yields} Its visible light photocatalytic activity is greatly higher than that of TiO{sub 2} (P-25) and its photocatalytic stability is excellent. {yields} Carbon self-doping and visible photosensitive organic groups result in the improvement of the visible light photocatalytic activity. -- Abstract: Highly efficient visible light TiO{sub 2} photocatalyst was prepared by the sol-gel method at lower temperature ({<=}300 {sup o}C), and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and differential scanning calorimetry-thermogravimetric analysis (DSC-TGA). The effects of the heat treatment temperature and time of the as-prepared TiO{sub 2} on its visible light photocatalytic activity were investigated by monitoring the degradation of methyl orange solution under visible light irradiation (wavelength {>=} 400 nm). Results show that the as-prepared TiO{sub 2} nanoparticles possess an anatase phase and mesoporous structure with carbon self-doping and visible photosensitive organic groups. The visible light photocatalytic activity of the as-prepared TiO{sub 2} is greatly higher than those of the commercial TiO{sub 2} (P-25) and other visible photocatalysts reported in literature (such as PPy/TiO{sub 2}, P3HT/TiO{sub 2}, PANI/TiO{sub 2}, N-TiO{sub 2} and Fe{sup 3+}-TiO{sub 2}) and its photocatalytic stability is excellent. The reasons for improving the visible light photocatalytic activity of the as-prepared TiO{sub 2} can be explained by carbon self-doping and a large amount of visible photosensitive groups existing in the as-prepared TiO{sub 2}. The apparent optical thickness ({tau}{sub app}), local

  18. Les effets des hyperliens visibles ou invisibles sur l'acquisition lexicale et sur la compréhension en lecture chez des apprenants intermédiaires et avancés en langue étrangère Effects of Visible and Invisible Hyperlinks on Vocabulary Acquisition and Reading Comprehension for High- and Average-Foreign Language Achievers

    Directory of Open Access Journals (Sweden)

    Ofelia R. Nikolova

    2004-12-01

    Full Text Available Cet article est consacré à l'étude des effets des hyperliens visibles et invisibles pour les mots annotés dans un environnement informatique centré sur l'acquisition de vocabulaire et la compréhension en lecture pour deux types d'apprenants, intermédiaires et avancés, en français. Deux cent soixante-quatre étudiants de français de deuxième semestre ont été identifiés comme intermédiaires ou avancés. Les étudiants de chaque type ont été ensuite assignés par tirage au sort en deux groupes ; un groupe utilisant des liens visibles et un autre des liens invisibles. Tous les étudiants ont reçu pour instruction de lire un court passage en français (181 mots dans un but de compréhension générale. Les étudiants ont reçu également la permission de consulter à loisir tous les mots annotés (marqués par des caractères gras pour le groupe avec liens visibles. Les apprenants ont été soumis à un prétest de vocabulaire et à des post-tests, immédiats et différés de deux semaines, de vocabulaire et de compréhension en lecture. Les résultats de l'étude ont démontré que les apprenants intermédiaires bénéficient mieux des liens visibles en ce qui concerne leur acquisition de vocabulaire et leur compréhension en lecture que les apprenants avancés. Ces résultats sont discutés dans le cadre des théories de l'apprentissage des langues secondes et des apprenants doués. Des suggestions de pistes pour des recherches futures sont proposées.This study investigated the effects of visible and invisible links for annotated words in a computer module for learning French on the vocabulary acquisition and reading comprehension of two types of students – high – and average-achievers. Two hundred and sixty four second-semester students of French were identified as high- or average-achievers. Each type of students was then randomly assigned to two groups – with visible or invisible hyperlinks. All students were instructed

  19. Top-cited articles reflect high impact of JMTP across many disciplines, not just marketing

    OpenAIRE

    Farrell, Andrew; Hair, Joe F.; Polonsky, Michael J.

    2016-01-01

    It is with pleasure that we introduce the Top 20 cited articles in the last decade of Journal of Marketing Theory and Practice (JMTP), and announce their free availability to the viewing public. With this special issue, we celebrate the wide-ranging impact and influence of one of marketing’s younger journals, with JMTP a spritely 24 years old. In terms of overall impact factors, taken from 2014 figures on Scopus, JMTP (1.467) ranks fourth among the broad-scope marketing journals. Ahead of JMT...

  20. A High Percentage of Beef Bull Pictures in Semen Catalogues Have Feet and Lower Legs that Are Not Visible

    Directory of Open Access Journals (Sweden)

    Marcy K. Franks

    2015-07-01

    Full Text Available A total of 1379 beef bull pictures were surveyed to determine visibility of feet and legs from four American semen company websites. Five different breeds were represented: Angus, Red Angus, Hereford (polled and horned, Simmental, and Charolais. In addition to visibility, data on other variables were collected to establish frequencies and correlations. These included breed, color, material that obscured visibility, such as grass, picture taken at livestock show or outside, semen company, photographer, video, and age of bull. A foot and leg visibility score was given to each bull picture. Only 19.4% of the pictures had fully visible feet and legs. Both the hooves and dewclaws were hidden on 32.5% of the pictures. Correlation between bull’s birthdate and the first four visibility scores was statistically significant (P < 0.0001. As age increased the feet and legs were more likely to be visible in the bull’s picture. This may possibly be due to greater availability of both photo editing software and digital photography. One positive finding was that 6% of the bulls had a video of the bull walking which completely showed his feet and legs.

  1. One-step growth of nanosheet-assembled BiOCl/BiOBr microspheres for highly efficient visible photocatalytic performance

    Science.gov (United States)

    Zhang, Jinfeng; Lv, Jiali; Dai, Kai; Liang, Changhao; Liu, Qi

    2018-02-01

    In this work, we have developed a simple synthetic approach of nanosheet-assembled BiOCl/BiOBr microspheres by an ethylene glycol (EG)-assisted hydrothermal method. The crystalline form, morphology, chemical composition, optical performance and surface area of BiOCl/BiOBr microspheres were identified using X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy spectra (EDX), UV-vis diffuse reflectance spectroscopy (DRS) analysis, high resolution X-ray photoelectron spectra (XPS) and N2 adsorption-desorption isotherms. BiOCl/BiOBr microspheres were nanosheet-assembled particles, which possessed visible light absorption under LED light irridation. Additionally, the methylene blue (MB) photodegradation performance of different BiOCl/BiOBr microspheres irradiated under 410 nm LED light arrays were investigated, the results exhibited that as-prepared BiOCl/BiOBr products showed higher catalytic effiency than pure BiOCl or BiOBr. By optimizing the composition ration of the BiOCl and BiOBr, up to 93% degradation rate can be obtained in the 40%BiOCl/BiOBr microspheres. Finally, the photocatalytic mechanism of BiOCl/BiOBr microspheres had been proposed.

  2. Phase transformation synthesis of TiO2/CdS heterojunction film with high visible-light photoelectrochemical activity

    Science.gov (United States)

    Liu, Canjun; Yang, Yahui; Li, Jie; Chen, Shu

    2018-06-01

    CdS/TiO2 heterojunction film used as a photoanode has attracted much attention in the past few years due to its good visible light photocatalytic activity. However, CdS/TiO2 films prepared by conventional methods (successive ionic layer adsorption and reaction, chemical bath deposition and electrodeposition) show numerous grain boundaries in the CdS layer and an imperfect contact at the heterojunction interface. In this study, we designed a phase transformation method to fabricate CdS/TiO2 nanorod heterojunction films. The characterization results showed that the CdS layer with fewer grain boundaries was conformally coated on the TiO2 nanorod surface and the formation mechanism has been explained in this manuscript. Moreover, the prepared CdS/TiO2 films show a high photocatalytic activity and the photocurrent density is as high as 9.65 mA cm‑2 at 0.80 V versus RHE. It may be attributed to fewer grain boundaries and a compact heterojunction contact, which can effectively improve charge separation and transportation.

  3. A spirooxazine derivative as a highly sensitive cyanide sensor by means of UV-visible difference spectroscopy.

    Science.gov (United States)

    Zhu, Shaoyin; Li, Minjie; Sheng, Lan; Chen, Peng; Zhang, Yumo; Zhang, Sean Xiao-An

    2012-12-07

    A spirooxazine derivative 2-nitro-5a-(2-(4-dimethylaminophenyl)-ethylene)-6,6-dimethyl-5a,6-dihydro-12H-indolo[2,1-b][1,3]benzooxazine (P1) was explored as a sensitive cyanide probe. Different from conventional spiropyrans, P1 avoided locating the 3H-indolium cation and the 4-nitrophenolate anion in the same conjugated structure, which enhanced the positive charge of 3H-indolium cation so that the sensitivity and reaction speed were improved highly. UV-visible difference spectroscopy using P1 detection solution as a timely reference improved the measurement accuracy, prevented the error caused by the inherent absorption change of P1 solution with time. This enabled the "positive-negative alternative absorption peaks" in difference spectrum to be used as a finger-print to distinguish whether the spectral change was caused by cyanide. Benefiting from the special design of the molecular structure and the strategy of difference spectroscopy, P1 showed high selectivity and sensitivity for CN(-). A detection limit of 0.4 μM and a rate constant of 1.1 s(-1) were achieved.

  4. Development of high-speed and wide-angle visible observation diagnostics on Experimental Advanced Superconducting Tokamak using catadioptric optics

    International Nuclear Information System (INIS)

    Yang, J. H.; Hu, L. Q.; Zang, Q.; Han, X. F.; Shao, C. Q.; Sun, T. F.; Chen, H.; Wang, T. F.; Li, F. J.; Hu, A. L.; Yang, X. F.

    2013-01-01

    A new wide-angle endoscope for visible light observation on the Experimental Advanced Superconducting Tokamak (EAST) has been recently developed. The head section of the optical system is based on a mirror reflection design that is similar to the International Thermonuclear Experimental Reactor-like wide-angle observation diagnostic on the Joint European Torus. However, the optical system design has been simplified and improved. As a result, the global transmittance of the system is as high as 79.6% in the wavelength range from 380 to 780 nm, and the spatial resolution is <5 mm for the full depth of field (4000 mm). The optical system also has a large relative aperture (1:2.4) and can be applied in high-speed camera diagnostics. As an important diagnostic tool, the optical system has been installed on the HT-7 (Hefei Tokamak-7) for its final experimental campaign, and the experiments confirmed that it can be applied to the investigation of transient processes in plasma, such as ELMy eruptions in H-mode, on EAST

  5. High energy beam thermal processing of alpha zirconium alloys and the resulting articles

    International Nuclear Information System (INIS)

    Sabol, G.P.; McDonald, S.G.; Nurminen, J.I.

    1983-01-01

    Alpha zirconium alloy fabrication methods and resultant products exhibiting improved high temperature, high pressure steam corrosion resistance. The process, according to one aspect of this invention, utilizes a high energy beam thermal treatment to provide a layer of beta treated microstructure on an alpha zirconium alloy intermediate product. The treated product is then alpha worked to final size. According to another aspect of the invention, high energy beam thermal treatment is used to produce an alpha annealed microstructure in a Zircaloy alloy intermediate size or final size component. The resultant products are suitable for use in pressurized water and boiling water reactors

  6. Invited review article: high-speed flexure-guided nanopositioning: mechanical design and control issues.

    Science.gov (United States)

    Yong, Y K; Moheimani, S O R; Kenton, B J; Leang, K K

    2012-12-01

    Recent interest in high-speed scanning probe microscopy for high-throughput applications including video-rate atomic force microscopy and probe-based nanofabrication has sparked attention on the development of high-bandwidth flexure-guided nanopositioning systems (nanopositioners). Such nanopositioners are designed to move samples with sub-nanometer resolution with positioning bandwidth in the kilohertz range. State-of-the-art designs incorporate uniquely designed flexure mechanisms driven by compact and stiff piezoelectric actuators. This paper surveys key advances in mechanical design and control of dynamic effects and nonlinearities, in the context of high-speed nanopositioning. Future challenges and research topics are also discussed.

  7. High-aggregate-capacity visible light communication links using stacked multimode polymer waveguides and micro-pixelated LED arrays

    Science.gov (United States)

    Bamiedakis, N.; McKendry, J. J. D.; Xie, E.; Gu, E.; Dawson, M. D.; Penty, R. V.; White, I. H.

    2018-02-01

    In recent years, light emitting diodes (LEDs) have gained renewed interest for use in visible light communication links (VLC) owing to their potential use as both high-quality power-efficient illumination sources as well as low-cost optical transmitters in free-space and guided-wave links. Applications that can benefit from their use include optical wireless systems (LiFi and Internet of Things), in-home and automotive networks, optical USBs and short-reach low-cost optical interconnects. However, VLC links suffer from the limited LED bandwidth (typically 100 MHz). As a result, a combination of novel LED devices, advanced modulation formats and multiplexing methods are employed to overcome this limitation and achieve high-speed (>1 Gb/s) data transmission over such links. In this work, we present recent advances in the formation of high-aggregate-capacity low cost guided wave VLC links using stacked polymer multimode waveguides and matching micro-pixelated LED (μLED) arrays. μLEDs have been shown to exhibit larger bandwidths (>200 MHz) than conventional broad-area LEDs and can be formed in large array configurations, while multimode polymer waveguides enable the formation of low-cost optical links onto standard PCBs. Here, three- and four-layered stacks of multimode waveguides, as well as matching GaN μLED arrays, are fabricated in order to generate high-density yet low-cost optical interconnects. Different waveguide topologies are implemented and are investigated in terms of loss and crosstalk performance. The initial results presented herein demonstrate good intrinsic crosstalk performance and indicate the potential to achieve >= 0.5 Tb/s/mm2 aggregate interconnection capacity using this low-cost technology.

  8. Controllable synthesis of ZnO nanoparticles with high intensity visible photoemission and investigation of its mechanism

    International Nuclear Information System (INIS)

    Lv Yunbo; Xiao Wen; Li Weiyan; Xue Junmin; Ding Jun

    2013-01-01

    ZnO is known as a good photoluminescent semiconductor due to its ability to emit visible light. However, the visible emission mechanism is still under debate. In this work, we have successfully synthesized nanoparticles using LiOH, KOH and NaOH as bases and have achieved visible emission of various colours, such as blue, cyan, green and orange. We demonstrate that LiOH is the most efficient base to control the properties of ZnO nanoparticle emission by varying LiOH concentration. Moreover, detailed studies by TEM, UV and XRD show that ZnO particle size plays an important role in the colour of the emitted light and smaller particles tend to emit shorter wavelength photons. The visible emission is suggested to arise from an electron transition from the conduction band to a deep-trapped defect state. Our experimental results suggest the presence of oxygen vacancies on the ZnO nanoparticle surface. (paper)

  9. Graphene oxide–CdS composite with high photocatalytic degradation and disinfection activities under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Peng; Liu, Jincheng [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Sun, Darren Delai, E-mail: DDSUN@ntu.edu.sg [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Ng, Wunjern [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore); Nanyang Environment and Water Research Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2013-04-15

    Highlights: ► GO–CdS composites were prepared through a novel two-phase mixing method. ► Uniform deposition of CdS nanoparticles on GO sheets. ► Reduced charge recombination rate. ► Enhanced photo-stability. ► High photodegradation and disinfection efficiency. -- Abstract: Graphene oxide (GO)–CdS composites were synthesized via a novel two-phase mixing method successfully. CdS nanoparticles were uniformly self-assembled on GO sheets at water/toluene interface. The photocatalytic degradation (photodegradation) and disinfection activities of GO–CdS composites were investigated thoroughly. The results show that GO–CdS composites exhibit higher efficiency in photodegradation of various water pollutants than pure CdS nanoparticles under visible light irradiation. In addition, the interactions between GO sheets and CdS nanoparticles inhibit the photo-corrosion of CdS and leaching of Cd{sup 2+}. Only 3.5 wt% Cd{sup 2+} of GO–CdS was leached out after photodegradation, while 38.6 wt% Cd{sup 2+} of CdS was lost into aqueous solution. Furthermore, the disinfection activity of GO–CdS composites was investigated for the first time. Nearly 100% of both Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) were killed within 25 min under visible light irradiation. The excellent performances of GO–CdS composites can be attributed to that (1) effective charge transfer from CdS to GO reduces the recombination rate of photo-generated electron–hole pairs; (2) uniform deposition of CdS on GO sheets eliminates aggregation of CdS nanoparticles; and (3) the strong interactions between GO and CdS enhancing the durability of GO–CdS composites. Finally, the mechanism behind these excellent performances was verified by transient photocurrent measurement and further confirmed by ESR technique as well as employing a radical scavenging species – dimethyl sulfoxide (DMSO)

  10. Graphene oxide–CdS composite with high photocatalytic degradation and disinfection activities under visible light irradiation

    International Nuclear Information System (INIS)

    Gao, Peng; Liu, Jincheng; Sun, Darren Delai; Ng, Wunjern

    2013-01-01

    Highlights: ► GO–CdS composites were prepared through a novel two-phase mixing method. ► Uniform deposition of CdS nanoparticles on GO sheets. ► Reduced charge recombination rate. ► Enhanced photo-stability. ► High photodegradation and disinfection efficiency. -- Abstract: Graphene oxide (GO)–CdS composites were synthesized via a novel two-phase mixing method successfully. CdS nanoparticles were uniformly self-assembled on GO sheets at water/toluene interface. The photocatalytic degradation (photodegradation) and disinfection activities of GO–CdS composites were investigated thoroughly. The results show that GO–CdS composites exhibit higher efficiency in photodegradation of various water pollutants than pure CdS nanoparticles under visible light irradiation. In addition, the interactions between GO sheets and CdS nanoparticles inhibit the photo-corrosion of CdS and leaching of Cd 2+ . Only 3.5 wt% Cd 2+ of GO–CdS was leached out after photodegradation, while 38.6 wt% Cd 2+ of CdS was lost into aqueous solution. Furthermore, the disinfection activity of GO–CdS composites was investigated for the first time. Nearly 100% of both Gram-negative Escherichia coli (E. coli) and Gram-positive Bacillus subtilis (B. subtilis) were killed within 25 min under visible light irradiation. The excellent performances of GO–CdS composites can be attributed to that (1) effective charge transfer from CdS to GO reduces the recombination rate of photo-generated electron–hole pairs; (2) uniform deposition of CdS on GO sheets eliminates aggregation of CdS nanoparticles; and (3) the strong interactions between GO and CdS enhancing the durability of GO–CdS composites. Finally, the mechanism behind these excellent performances was verified by transient photocurrent measurement and further confirmed by ESR technique as well as employing a radical scavenging species – dimethyl sulfoxide (DMSO)

  11. Process for the production of prismatic graphite molded articles for high temperature fuel elements

    International Nuclear Information System (INIS)

    Huschka, H.; Rachor, L.; Hrovat, M.; Wolff, W.

    1976-01-01

    Prismatic graphite molded objects for high temperature fuel elements are prepared by producing the outer geometry and the holes for cooling channels and for receiving fuel and fertile materials in the formation of the carbon object

  12. Development of high efficient visible light-driven N, S-codoped TiO2 nanowires photocatalysts

    Science.gov (United States)

    Zhang, Yanlin; Liu, Peihong; Wu, Honghai

    2015-02-01

    One-dimensional (1D) nanowire material (especially nonmetal doped 1D nanowires) synthesized by a facile way is of great significance and greatly desired as it has higher charge carrier mobility and lower carrier recombination rate. N, S-codoped TiO2 nanowires were synthesized using titanium sulfate as a precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, HRTEM, SAED, XPS, BET and UV-vis absorption spectrum. The incorporation of N and S into TiO2 NWs can lead to the expansion of its lattice and remarkably lower its electron-transfer resistance. Photocatalytic activity measurement showed that the N, S-codoped TiO2 nanowires with high quantum efficiency revealed the best photocatalytic performance for atrazine degradation under visible light irradiation compared to N, S-codoped TiO2 nanoparticles and S-doped TiO2 nanowires, which was attributed to (i) the synergistic effect of N and S doping in narrowing the band gap, separating electron-hole pairs and increasing the photoinduced electrons, and (ii) extending the anatase-to-rutile transformation temperature above 600 °C.

  13. Indoor high precision three-dimensional positioning system based on visible light communication using modified genetic algorithm

    Science.gov (United States)

    Chen, Hao; Guan, Weipeng; Li, Simin; Wu, Yuxiang

    2018-04-01

    To improve the precision of indoor positioning and actualize three-dimensional positioning, a reversed indoor positioning system based on visible light communication (VLC) using genetic algorithm (GA) is proposed. In order to solve the problem of interference between signal sources, CDMA modulation is used. Each light-emitting diode (LED) in the system broadcasts a unique identity (ID) code using CDMA modulation. Receiver receives mixed signal from every LED reference point, by the orthogonality of spreading code in CDMA modulation, ID information and intensity attenuation information from every LED can be obtained. According to positioning principle of received signal strength (RSS), the coordinate of the receiver can be determined. Due to system noise and imperfection of device utilized in the system, distance between receiver and transmitters will deviate from the real value resulting in positioning error. By introducing error correction factors to global parallel search of genetic algorithm, coordinates of the receiver in three-dimensional space can be determined precisely. Both simulation results and experimental results show that in practical application scenarios, the proposed positioning system can realize high precision positioning service.

  14. Automatic identification of high impact articles in PubMed to support clinical decision making.

    Science.gov (United States)

    Bian, Jiantao; Morid, Mohammad Amin; Jonnalagadda, Siddhartha; Luo, Gang; Del Fiol, Guilherme

    2017-09-01

    The practice of evidence-based medicine involves integrating the latest best available evidence into patient care decisions. Yet, critical barriers exist for clinicians' retrieval of evidence that is relevant for a particular patient from primary sources such as randomized controlled trials and meta-analyses. To help address those barriers, we investigated machine learning algorithms that find clinical studies with high clinical impact from PubMed®. Our machine learning algorithms use a variety of features including bibliometric features (e.g., citation count), social media attention, journal impact factors, and citation metadata. The algorithms were developed and evaluated with a gold standard composed of 502 high impact clinical studies that are referenced in 11 clinical evidence-based guidelines on the treatment of various diseases. We tested the following hypotheses: (1) our high impact classifier outperforms a state-of-the-art classifier based on citation metadata and citation terms, and PubMed's® relevance sort algorithm; and (2) the performance of our high impact classifier does not decrease significantly after removing proprietary features such as citation count. The mean top 20 precision of our high impact classifier was 34% versus 11% for the state-of-the-art classifier and 4% for PubMed's® relevance sort (p=0.009); and the performance of our high impact classifier did not decrease significantly after removing proprietary features (mean top 20 precision=34% vs. 36%; p=0.085). The high impact classifier, using features such as bibliometrics, social media attention and MEDLINE® metadata, outperformed previous approaches and is a promising alternative to identifying high impact studies for clinical decision support. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Improving Positioning in High-Dose Radiotherapy for Prostate Cancer: Safety and Visibility of Frequently Used Gold Fiducial Markers

    Energy Technology Data Exchange (ETDEWEB)

    Fonteyne, Valerie, E-mail: valerie.fonteyne@uzgent.be [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Ost, Piet [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium); Villeirs, Geert [Department of Radiology, Ghent University Hospital, Ghent (Belgium); Oosterlinck, Willem [Department of Urology, Ghent University Hospital, Ghent (Belgium); Impens, Aline; De Gersem, Werner; De Wagter, Carlos; De Meerleer, Gert [Department of Radiotherapy, Ghent University Hospital, Ghent (Belgium)

    2012-05-01

    Purpose: The use of gold fiducial markers (GFMs) for prostate positioning in high-dose radiotherapy is gaining interest. The purpose of this study was to compare five GFMs regarding feasibility of ultrasound-based implantation in the prostate and intraprostatic lesion (IPL); toxicity; visibility on transabdominal ultrasound (TU) and cone-beam CT (CBCT); reliability of automatic, soft tissue, and GFM-based CBCT patient positioning by comparing manual and automatic fusion CBCT. Methods and Materials: Twenty-five patients were included. Pain and toxicity were scored after implantation and high-dose radiotherapy. Fisher exact test was used to evaluate the correlation of patients' characteristics and prostatitis. Positioning was evaluated on TU and kilovoltage CBCT images. CBCT fusion was performed automatically (Elekta XVI technology, release 3.5.1 b27, based on grey values) and manually on soft tissue and GFMs. Pearson correlation statistics and Bland-Altman evaluation were used. Five GFMs were compared. Results: Twenty percent of the patients developed prostatitis despite antibiotic prophylaxis. Cigarette smoking was significantly correlated with prostatitis. The visualization of all GFMs on TU was disappointing. Consequently we cannot recommend the use of these GFMs for TU-based prostate positioning. For all GFMs, there was only fair to poor linear correlation between automatic and manual CBCT images, indicating that even when GFMs are used, an operator evaluation is imperative. However, when GFMs were analyzed individually, a moderate to very strong correlation between automatic and manual positioning was found for larger GFMs in all directions. Conclusion: The incidence of prostatitis in our series was high. Further research is imperative to define the ideal preparation protocol preimplantation and to select patients. Automatic fusion is more reliable with larger GFMs at the cost of more scatter. The stability of all GFMs was proven.

  16. Control of New Copper Corrosion in High-Alkalinity Drinking Water using Orthophosphate - article

    Science.gov (United States)

    Research and field experience have shown that high-alkalinity waters can be associated with elevated copper levels in drinking water. The objective of this study was to document the application of orthophosphate to the distribution system of a building with a copper problem asso...

  17. Article choice in children with High Functioning Autism (HFA) and in children with Specific Language Impairment (SLI).

    NARCIS (Netherlands)

    Schaeffer, J.; van Witteloostuijn, M.; de Haan, D.

    2014-01-01

    This study reports on the choice between a definite and an indefinite article by children with High Functioning Autism (HFA) and children with Specific Language Impairment (SLI). We carried out an elicited production task with 16 Dutch-speaking non-grammatically impaired children with HFA aged 6-13,

  18. Improving urban visibility through fractal analysis of street edges: The case of John Evans Atta Mills High Street in Accra, Ghana

    Directory of Open Access Journals (Sweden)

    R.A. Oppong

    2017-06-01

    Full Text Available Streets are a representation of cities, and the image of a city is a reflection of its home country. Although attempts to ensure harmonious spatial and environmental development in Ghanaian settlements date back to the colonial era, these efforts have minimal physical manifestation in the urban fabric of the city of Accra. The Independence Arch of Ghana, an important landmark in the urban fabric and history of Accra, lacks the striking vista and approach it deserves. This paper introduces the use of fractal analysis of street edges to understand the characteristics of the John Evans Atta Mills (JEAM High Street for developing recommendations to improve visibility along its stretch and the overall image of the city. The box-counting method with visual survey was used in research. The pertinent questions this paper seeks to address are as follows: What factors affect the visibility and imageability of JEAM High Street? What design aspects should be considered to improve urban visibility along JEAM High Street? What is the link of fractals to urban design and architecture? The paper recommends various design considerations and qualities to improve the urban visibility and imageability of JEAM High Street.

  19. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

    OpenAIRE

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C.

    2013-01-01

    Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).

  20. Invited Article: High resolution angle resolved photoemission with tabletop 11 eV laser

    Energy Technology Data Exchange (ETDEWEB)

    He, Yu; Vishik, Inna M.; Yi, Ming; Yang, Shuolong; Lee, James J.; Chen, Sudi; Rebec, Slavko N.; Leuenberger, Dominik; Shen, Zhi-Xun [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Liu, Zhongkai [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); Zong, Alfred [Department of Physics, Stanford University, Stanford, California 94305 (United States); Jefferson, C. Michael; Merriam, Andrew J. [Lumeras LLC, 207 McPherson St, Santa Cruz, California 95060 (United States); Moore, Robert G.; Kirchmann, Patrick S. [SIMES, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2016-01-15

    We developed a table-top vacuum ultraviolet (VUV) laser with 113.778 nm wavelength (10.897 eV) and demonstrated its viability as a photon source for high resolution angle-resolved photoemission spectroscopy (ARPES). This sub-nanosecond pulsed VUV laser operates at a repetition rate of 10 MHz, provides a flux of 2 × 10{sup 12} photons/s, and enables photoemission with energy and momentum resolutions better than 2 meV and 0.012 Å{sup −1}, respectively. Space-charge induced energy shifts and spectral broadenings can be reduced below 2 meV. The setup reaches electron momenta up to 1.2 Å{sup −1}, granting full access to the first Brillouin zone of most materials. Control over the linear polarization, repetition rate, and photon flux of the VUV source facilitates ARPES investigations of a broad range of quantum materials, bridging the application gap between contemporary low energy laser-based ARPES and synchrotron-based ARPES. We describe the principles and operational characteristics of this source and showcase its performance for rare earth metal tritellurides, high temperature cuprate superconductors, and iron-based superconductors.

  1. ARTICLES / SAGGI

    African Journals Online (AJOL)

    laws and take measures to deal with the growing influx of foreigners. ... gained major visibility in the Italian literary context. ... foreign-born writers who write in Italian and by Italian writers who .... Richter notes that the “increasing circulation of subjects in intercultural .... The city becomes the refraction of global processes of.

  2. Photogenerated carriers transfer in dye-graphene-SnO2 composites for highly efficient visible-light photocatalysis.

    Science.gov (United States)

    Zhuang, Shendong; Xu, Xiaoyong; Feng, Bing; Hu, Jingguo; Pang, Yaru; Zhou, Gang; Tong, Ling; Zhou, Yuxue

    2014-01-08

    The visible-light-driven photocatalytic activities of graphene-semiconductor catalysts have recently been demonstrated, however, the transfer pathway of photogenerated carriers especially where the role of graphene still remains controversial. Here we report graphene-SnO2 aerosol nanocomposites that exhibit more superior dye adsorption capacity and photocatalytic efficiency compared with pure SnO2 quantum dots, P25 TiO2, and pure graphene aerosol under the visible light. This study examines the origin of the visible-light-driven photocatalysis, which for the first time links to the synergistic effect of the cophotosensitization of the dye and graphene to SnO2. We hope this concept and corresponding mechanism of cophotosensitization could provide an original understanding for the photocatalytic reaction process at the level of carrier transfer pathway as well as a brand new approach to design novel and versatile graphene-based composites for solar energy conversion.

  3. MoS2 quantum dots@TiO2 nanotube composites with enhanced photoexcited charge separation and high-efficiency visible-light driven photocatalysis

    Science.gov (United States)

    Zhao, Fenfen; Rong, Yuefei; Wan, Junmin; Hu, Zhiwen; Peng, Zhiqin; Wang, Bing

    2018-03-01

    MoS2 quantum dots (QDs) that are 5 nm in size were deposited on the surface of ultrathin TiO2 nanotubes (TNTs) with 5 nm wall thickness by using an improved hydrothermal method to form a MoS2 QDs@TNT visible-light photocatalyst. The ultrathin TNTs with high percentage of photocatalytic reactive facets were fabricated by the commercially available TiO2 nanoparticles (P25) through an improved hydrothermal method, and the MoS2 QDs were acquired by using a surfactant-assisted technique. The novel MoS2 QDs@TNT photocatalysts showed excellent photocatalytic activity with a decolorization rate of 92% or approximately 3.5 times more than that of pure TNTs for the high initial concentration of methylene blue solution (20 mg l-1) within 40 min under visible-light irradiation. MoS2 as the co-catalysts favored the broadening of TNTs into the visible-light absorption scope. The quantum confinement and edge effects of the MoS2 QDs and the heterojunction formed between the MoS2 QDs and TNTs efficiently extended the lifetime of photoinduced charges, impeded the recombination of photoexcited electron-hole pairs, and improved the visible-light-driven high-efficiency photocatalysis.

  4. Utilization of Large Scale Surface Models for Detailed Visibility Analyses

    Science.gov (United States)

    Caha, J.; Kačmařík, M.

    2017-11-01

    This article demonstrates utilization of large scale surface models with small spatial resolution and high accuracy, acquired from Unmanned Aerial Vehicle scanning, for visibility analyses. The importance of large scale data for visibility analyses on the local scale, where the detail of the surface model is the most defining factor, is described. The focus is not only the classic Boolean visibility, that is usually determined within GIS, but also on so called extended viewsheds that aims to provide more information about visibility. The case study with examples of visibility analyses was performed on river Opava, near the Ostrava city (Czech Republic). The multiple Boolean viewshed analysis and global horizon viewshed were calculated to determine most prominent features and visibility barriers of the surface. Besides that, the extended viewshed showing angle difference above the local horizon, which describes angular height of the target area above the barrier, is shown. The case study proved that large scale models are appropriate data source for visibility analyses on local level. The discussion summarizes possible future applications and further development directions of visibility analyses.

  5. Social media visibility

    DEFF Research Database (Denmark)

    Uldam, Julie

    2018-01-01

    of activists remains under-researched. This article examines BP’s surveillance of activists who criticise the company’s corporate social responsibility (CSR) programme as ‘greenwashing’. In this way, it goes beyond corporations’ uses of big data and instead explores how they monitor and discuss strategies......As activists move from alternative media platforms to commercial social media platforms, they face increasing challenges in protecting their online security and privacy. While government surveillance of activists is well-documented in scholarly research and the media, corporate surveillance...... for responding to the activities of individual activists in social media. It shows that while social media afford an unprecedented level of visibility for activists, it comes with the risk of being monitored by corporations. Theoretically, it draws on conceptions of visibility in social sciences and media...

  6. Hydrothermal growth of two dimensional hierarchical MoS2 nanospheres on one dimensional CdS nanorods for high performance and stable visible photocatalytic H2 evolution

    Science.gov (United States)

    Chava, Rama Krishna; Do, Jeong Yeon; Kang, Misook

    2018-03-01

    The visible photocatalytic H2 production from water splitting considered as a clean and renewable energy source could solve the problem of greenhouse gas emission from fossil fuels. Despite tremendous efforts, the development of cost effective, highly efficient and more stable visible photocatalysts for splitting of water remains a great challenge. Here, we report the heteronanostructures consisting of hierarchical MoS2 nanospheres grown on 1D CdS nanorods referred to as CdS-MoS2 HNSs as a high performance visible photocatalyst for H2 evolution. The as-synthesized CdS-MoS2 HNSs exhibited ∼11 fold increment of H2 evolution rate when compared to pure CdS nanorods. This remarkable enhanced hydrogen evolution performance can be assigned to the positive synergetic effect from heteronanostructures formed between the CdS and MoS2 components which assist as an electron sink and source for abundant active edge sites and in turn increases the charge separation. This study presents a low-cost visible photocatalyst for solar energy conversion to achieve efficient H2.

  7. A highly uniform ZnO/NaTaO3 nanocomposite: Enhanced self-sensitized degradation of colored pollutants under visible light

    International Nuclear Information System (INIS)

    Xing, Guanjie; Tang, Changhe; Zhang, Bo; Zhao, Lanxiao; Su, Yiguo; Wang, Xiaojing

    2015-01-01

    In this study, a highly uniform ZnO/NaTaO 3 composite was prepared via simple hydrothermal synthesis. XRD confirmed the composite was constructed by pure cubic phase of NaTaO 3 and hexagonal phase of ZnO. SEM analysis showed that as-prepared ZnO/NaTaO 3 shaped as an irregular ginger with an obviously smaller size than that of pure ZnO without obvious agglomeration. EDS mapping demonstrated that the four elements (Na, Ta, O, Zn) in the composite were very uniformly distributed. The photocatalytic behaviors of as-prepared composites were studied in the degradation of methylene blue both under UV and visible irradiation. The bare ZnO showed the highest activity with 99.8% methylene blue (MB) photodegraded in 70 min under UV light irradiation whereas 94% photodegraded rate was achieved for ZnO/NaTaO 3 . More importantly, the uniform composite of ZnO/NaTaO 3 exhibited effective degradation of methylene blue under visible light which can be attributed to the well dyes adsorption abilities and the high efficiency of electron separation, induced by the synergistic effect between ZnO and NaTaO 3 . It is confirmed the dye rather than a semiconductor is excited under visible light irradiation and a self-sensitized photocatalytic mechanism was then proposed based on the experimental results. - Graphical abstract: Visible light photocatalytic activity of ZnO/NaTaO 3 and proposed schematic of self-sensitization directed photogradation of MB. - Highlights: • Highly uniform ZnO/NaTaO 3 photocatalysts were fabricated by hydrothermal method. • ZnO/NaTaO 3 composite exhibited effective degradation of MB under visible light. • ZnO/NaTaO 3 composite effectively promoted dye adsorption and electrons separation. • A self-sensitized photocatalytic mechanism was proposed for the degradation of dye

  8. Feature Article

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Feature Article. Articles in Resonance – Journal of Science Education. Volume 1 Issue 1 January 1996 pp 80-85 Feature Article. What's New in Computers Windows 95 · Vijnan Shastri · More Details Fulltext PDF. Volume 1 Issue 1 January 1996 pp 86-89 Feature ...

  9. Calculation procedure of temperature carditions of building-up and high frequency current brazing of articles of complex shape

    International Nuclear Information System (INIS)

    Ivnitskij, B.Ya.

    1984-01-01

    A technique of calculating the temperature regime of building-up and high frequency current brazing of articles of complex shape is suggested. The technique consists in division of complex detail into several simple components. Heat balances equation is compiled for each of them taking into account the heat exchange with other elements. It is possible to determine optimum regimes for heating and cooling rather efficiently using a computer

  10. TU-E-217BCD-06: Cone Beam Breast CT with a High Resolution Flat Panel Detector-Improvement of Calcification Visibility.

    Science.gov (United States)

    Shen, Y; Zhong, Y; Lai, C; Wang, T; Shaw, C

    2012-06-01

    To investigate the advantage of a high resolution flat panel detector for improving the visibility of microcalcifications (MCs) in cone beam breast CT Methods: A paraffin cylinder was used to simulate a 100% adipose breast. Calcium carbonate grains, ranging from 125-140 μm to 224 - 250 μm in size, were used to simulate the MCs. Groups of 25 same size MCs were embedded at the phantom center. The phantom was scanned with a bench-top CBCT system at various exposure levels. A 75μm pitch flat panel detector (Dexela 2923, Perkin Elmer) with 500μm thick CsI scintillator plate was used as the high resolution detector. A 194 μm pitch detector (Paxscan 4030CB, Varian Medical Systems) was used for reference. 300 projection images were acquired over 360° and reconstructed. The images were reviewed by 6 readers. The MC visibility was quantified as the fraction of visible MCs and averaged for comparison. The visibility was plotted as a function of the estimated dose level for various MC sizes and detectors. The MTFs and DQEs were measured and compared. For imaging small (200 μm and smaller) MCs, the visibility achieved with the 75μm pitch detector was found to be significantly higher than those achieved with the 194μm pitch detector. For imaging larger MCs, there was little advantage in using the 75μm pitch detector. Using the 75μm pitch detector, MCs as small as 180 μm could be imaged to achieve a visibility of 78% with an isocenter tissue dose of ∼20 mGys versus 62% achieved with the 194 μm pitch detector at the same dose level. It was found that a high pitch flat panel detector had the advantages of extending its imaging capability to higher frequencies thus helping improve the visibility when used to image small MCs. This work was supported in part by grants CA104759, CA13852 and CA124585 from NIH-NCI, a grant EB00117 from NIH-NIBIB, and a subcontract from NIST-ATP. © 2012 American Association of Physicists in Medicine.

  11. Room-temperature synthesis of Zn(0.80)Cd(0.20)S solid solution with a high visible-light photocatalytic activity for hydrogen evolution.

    Science.gov (United States)

    Wang, Dong-Hong; Wang, Lei; Xu, An-Wu

    2012-03-21

    Visible light photocatalytic H(2) production from water splitting is of great significance for its potential applications in converting solar energy into chemical energy. In this study, a series of Zn(1-x)Cd(x)S solid solutions with a nanoporous structure were successfully synthesized via a facile template-free method at room temperature. The obtained solid solutions were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS) and N(2) adsorption-desorption analysis. The solid solutions show efficient photocatalytic activity for H(2) evolution from aqueous solutions containing sacrificial reagents S(2-) and SO(3)(2-) under visible-light irradiation without a Pt cocatalyst, and loading of the Pt cocatalyst further improves the visible-light photocatalytic activity. The optimal photocatalyst with x = 0.20 prepared at pH = 7.3 displays the highest activity for H(2) evolution. The bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S nanoparticles exhibit a high H(2) evolution rate of 193 μmol h(-1) and 458 μmol h(-1) under visible-light irradiation (λ ≥ 420 nm), respectively. In addition, the bare and 0.25 wt% Pt loaded Zn(0.80)Cd(0.20)S catalysts show a high H(2) evolution rate of 252 and 640 μmol h(-1) under simulated solar light irradiation, respectively. Moreover, the Zn(0.80)Cd(0.20)S catalyst displays a high photocatalytic stability for H(2) evolution under long-term light irradiation. The incorporation of Cd in the solid solution leads to the visible light absorption, and the high content of Zn in the solid solution results in a relatively negative conduction band, a modulated band gap and a rather wide valence bandwidth, which are responsible for the excellent photocatalytic performance of H(2) production and for the high photostability

  12. In Situ UV-Visible Assessment of Iron-Based High-Temperature Water-Gas Shift Catalysts Promoted with Lanthana: An Extent of Reduction Study

    Directory of Open Access Journals (Sweden)

    Basseem B. Hallac

    2018-02-01

    Full Text Available The extent of reduction of unsupported iron-based high-temperature water-gas shift catalysts with small (<5 wt % lanthana contents was studied using UV-visible spectroscopy. Temperature- programmed reduction measurements showed that lanthana content higher than 0.5 wt % increased the extent of reduction to metallic Fe, while 0.5 wt % of lanthana facilitated the reduction to Fe3O4. In situ measurements on the iron oxide catalysts using mass and UV-visible spectroscopies permitted the quantification of the extent of reduction under temperature-programmed reduction and high-temperature water-gas shift conditions. The oxidation states were successfully calibrated against normalized absorbance spectra of visible light using the Kubelka-Munk theory. The normalized absorbance relative to the fully oxidized Fe2O3 increased as the extent of reduction increased. XANES suggested that the average bulk iron oxidation state during the water-gas shift reaction was Fe+2.57 for the catalyst with no lanthana and Fe+2.54 for the catalysts with 1 wt % lanthana. However, the UV-vis spectra suggest that the surface oxidation state of iron would be Fe+2.31 for the catalyst with 1 wt % lanthana if the oxidation state of iron in the catalyst with 0 wt % lanthana were Fe+2.57. The findings of this paper emphasize the importance of surface sensitive UV-visible spectroscopy for determining the extent of catalyst reduction during operation. The paper highlights the potential to use bench-scale UV-visible spectroscopy to study the surface chemistry of catalysts instead of less-available synchrotron X-ray radiation facilities.

  13. ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light

    Science.gov (United States)

    Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

    2016-08-01

    We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

  14. ZnCr2S4: Highly effective photocatalyst converting nitrate into N2 without over-reduction under both UV and pure visible light.

    Science.gov (United States)

    Yue, Mufei; Wang, Rong; Cheng, Nana; Cong, Rihong; Gao, Wenliang; Yang, Tao

    2016-08-03

    We propose several superiorities of applying some particular metal sulfides to the photocatalytic nitrate reduction in aqueous solution, including the high density of photogenerated excitons, high N2 selectivity (without over-reduction to ammonia). Indeed, ZnCr2S4 behaved as a highly efficient photocatalyst, and with the assistance of 1 wt% cocatalysts (RuOx, Ag, Au, Pd, or Pt), the efficiency was greatly improved. The simultaneous loading of Pt and Pd led to a synergistic effect. It offered the highest nitrate conversion rate of ~45 mg N/h together with the N2 selectivity of ~89%. Such a high activity remained steady after 5 cycles. The optimal apparent quantum yield at 380 nm was 15.46%. More importantly, with the assistance of the surface plasma resonance effect of Au, the visible light activity achieved 1.352 mg N/h under full arc Xe-lamp, and 0.452 mg N/h under pure visible light (λ > 400 nm). Comparing to the previous achievements in photocatalytic nitrate removal, our work on ZnCr2S4 eliminates the over-reduction problem, and possesses an extremely high and steady activity under UV-light, as well as a decent conversion rate under pure visible light.

  15. Dispersed-nanoparticle loading synthesis for monodisperse Au-titania composite particles and their crystallization for highly active UV and visible photocatalysts.

    Science.gov (United States)

    Sakamoto, Takeshi; Nagao, Daisuke; Noba, Masahiro; Ishii, Haruyuki; Konno, Mikio

    2014-06-24

    Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol-gel reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 °C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 °C followed by calcination at 500 °C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 °C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity.

  16. Efficient degradation of Methylene Blue dye over highly reactive Cu doped strontium titanate (SrTiO3) nanoparticles photocatalyst under visible light.

    Science.gov (United States)

    Rahman, Qazi Inamur; Ahmad, Musheer; Misra, Sunil Kumar; Lohani, Minaxi

    2012-09-01

    Visible light induced photocatalysts of Cu doped SrTiO3 (Cu/SrTiO3) nanoparticles with the size -60-75 nm were prepared via facile sol-gel method. The morphological, optical, crystalline properties and compositions of synthesized Cu/SrTiO3 nanoparticles were thoroughly characterized by field emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), ultra violet-visible spectroscopy (UV-Vis) and energy dispersive X-ray (EDX). A significant red shift in the UV-diffused reflectance spectrum was observed and the absorption edge shifted to visible region by the Cu doping. Surprisingly, the band gap of SrTiO3 was changed from 3.2 eV drop to 2.96 eV. The photocatalytic activity of the synthesized Cu/SrTiO3 nanoparticles was demonstrated for the degradation of Methylene Blue dye under visible light irradiation. The formation of new acceptor region in Cu/SrTiO3 was responsible for high photocatalytic activity of Cu/SrTiO3 nanoparticles. The results showed that the Methylene Blue dye was degraded by -66% within time span of 2 h over the Cu/SrTiO3 nanoparticles. This dye degradation reaction followed the Langmuir-Hinshelwood kinetics and also exhibited first order reaction rate. The calculated rate constant for the degradation reaction following first order kinetics was k = 0.0016 min(-1).

  17. Invited Article: Multiple-octave spanning high-energy mid-IR supercontinuum generation in bulk quadratic nonlinear crystals

    Directory of Open Access Journals (Sweden)

    Binbin Zhou

    2016-08-01

    Full Text Available Bright and broadband coherent mid-IR radiation is important for exciting and probing molecular vibrations. Using cascaded nonlinearities in conventional quadratic nonlinear crystals like lithium niobate, self-defocusing near-IR solitons have been demonstrated that led to very broadband supercontinuum generation in the visible, near-IR, and short-wavelength mid-IR. Here we conduct an experiment where a mid-IR crystal is pumped in the mid-IR. The crystal is cut for noncritical interaction, so the three-wave mixing of a single mid-IR femtosecond pump source leads to highly phase-mismatched second-harmonic generation. This self-acting cascaded process leads to the formation of a self-defocusing soliton at the mid-IR pump wavelength and after the self-compression point multiple octave-spanning supercontinua are observed. The results were recorded in a commercially available crystal LiInS2 pumped in the 3-4 μm range with 85 fs 50 μJ pulse energy, with the broadest supercontinuum covering 1.6-7.0 μm. We measured up 30 μJ energy in the supercontinuum, and the energy promises to scale favorably with an increased pump energy. Other mid-IR crystals can readily be used as well to cover other pump wavelengths and target other supercontinuum wavelength ranges.

  18. Mechanochemically synthesized sub-5 nm sized CuS quantum dots with high visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shun; Ge, Zhen-Hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhang, Bo-Ping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Yao, Yao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Huan-Chun [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Yang, Jing; Li, Yan; Gao, Chao [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Lin, Yuan-Hua [School of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China)

    2016-10-30

    Highlights: • CuS quantum dots (<5 nm) were synthesized by mechanochemical ball milling. • Defects was observed in the CuS quantum dots. • They show good visible light photocatalytic activity as Fenton-like reagents. - Abstract: We report a simple mechanochemical ball milling method for synthesizing monodisperse CuS quantum dots (QDs) with sizes as small as sub-5 nm. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The CuS QDs exhibited excellent visible-light-driven photocatalytic activity and stability for degradation of Rodanmine B aqueous solution as Fenton-like reagents. Our study opens the opportunity to low-cost and facile synthesis of QDs in large scale for future industrial applications.

  19. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

    Science.gov (United States)

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C

    2013-10-01

    To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat

  20. Highly Efficient Low-Temperature N-Doped TiO2 Catalysts for Visible Light Photocatalytic Applications

    Science.gov (United States)

    Mahy, Julien G.; Cerfontaine, Vincent; Devred, François; Gaigneaux, Eric M.; Heinrichs, Benoît; Lambert, Stéphanie D.

    2018-01-01

    In this paper, TiO2 prepared with an aqueous sol-gel synthesis by peptization process is doped with nitrogen precursor to extend its activity towards the visible region. Three N-precursors are used: urea, ethylenediamine and triethylamine. Different molar N/Ti ratios are tested and the synthesis is adapted for each dopant. For urea- and trimethylamine-doped samples, anatase-brookite TiO2 nanoparticles of 6–8 nm are formed, with a specific surface area between 200 and 275 m2·g−1. In ethylenediamine-doped samples, the formation of rutile phase is observed, and TiO2 nanoparticles of 6–8 nm with a specific surface area between 185 and 240 m2·g−1 are obtained. X-ray photoelectron spectroscopy (XPS) and diffuse reflectance measurements show the incorporation of nitrogen in TiO2 materials through Ti–O–N bonds allowing light absorption in the visible region. Photocatalytic tests on the remediation of water polluted with p-nitrophenol show a marked improvement for all doped catalysts under visible light. The optimum doping, taking into account cost, activity and ease of synthesis, is up-scaled to a volume of 5 L and compared to commercial Degussa P25 material. This up-scaled sample shows similar properties compared to the lab-scale sample, i.e., a photoactivity 4 times higher than commercial P25. PMID:29642626

  1. AgBr/MgBi2O6 heterostructured composites with highly efficient visible-light-driven photocatalytic activity

    Science.gov (United States)

    Zhong, Liansheng; Hu, Chaohao; Zhuang, Jing; Zhong, Yan; Wang, Dianhui; Zhou, Huaiying

    2018-06-01

    AgBr/MgBi2O6 heterostructured photocatalysts were synthesized by the deposition-precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS) were employed to examine the phase structure, morphology and optical properties of the as-prepared samples. The photocatalytic activity was investigated by decomposing methylene blue (MB) solution under visible light irradiation (λ > 420 nm). AgBr/MgBi2O6 composites exhibited significantly enhanced visible-light-driven photocatalytic properties in comparison with pure MgBi2O6 and AgBr. When the molar ratio of AgBr to MgBi2O6 was 3:1, the composite catalyst showed the optimal photocatalytic activity and excellent stability. The enhanced photocatalytic activity of AgBr/MgBi2O6 composites was attributed to the formation of p-n heterojunction between AgBr and MgBi2O6, thereby resulting in the effective separation and transfer of photogenerated electrons-hole pairs.

  2. Highly Enhanced Photoreductive Degradation of Polybromodiphenyl Ethers with g-C3N4/TiO2 under Visible Light Irradiation

    Directory of Open Access Journals (Sweden)

    Weidong Ye

    2017-04-01

    Full Text Available A series of high activity photocatalysts g-C3N4-TiO2 were synthesized by simple one-pot thermal transformation method and characterized by transmission electron microscopy (TEM, scanning electron microscopy (SEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller (BET surface area, and ultraviolet–visible diffuse reflectance spectroscopy (UV-Vis-DRS. The g-C3N4-TiO2 samples show highly improved photoreductive capability for the degradation of polybromodiphenyl ethers compared with g-C3N4 under visible light irradiation. Among all the hybrids, 0.02-C3N4-TiO2 with 2 wt % g-C3N4 loaded shows the highest reaction rate, which is 15 times as high as that in bare g-C3N4. The well-matched band gaps in heterojunction g-C3N4-TiO2 not only strengthen the absorption intensity, but also show more effective charge carrier separation, which results in the highly enhanced photoreductive performance under visible light irradiation. The trapping experiments show that holetrapping agents largely affect the reaction rate. The rate of electron accumulation in the conductive band is the rate-determining step in the degradation reaction. A possible photoreductive mechanism has been proposed.

  3. ARTICLES RECEIVED

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    The following articles have been submitted for possible publication in Teaching English in China. For reasons of space or priority they have not been able to be included. If you are interested in further information about an article please contact the author direct at the address given below.

  4. Synthesis and highly visible-induced photocatalytic activity of CNT-CdSe composite for methylene blue solution

    Directory of Open Access Journals (Sweden)

    Chen Ming-Liang

    2011-01-01

    Full Text Available Abstract Carbon nanotube-cadmium selenide (CNT-CdSe composite was synthesized by a facile hydrothermal method derived from multi-walled carbon nanotubes as a stating material. The as-prepared products were characterized by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis, transmission electron microscopy (TEM, and UV-vis diffuse reflectance spectrophotometer. The as-synthesized CNT-CdSe composite efficiently catalyzed the photodegradation of methylene blue in aqueous solutions under visible-light irradiation, exhibiting higher photocatalytic activity.

  5. Visible-light photocatalytic activity of the metastable Bi20TiO32 synthesized by a high-temperature quenching method

    International Nuclear Information System (INIS)

    Cheng Hefeng; Huang Baibiao; Dai Ying; Qin Xiaoyan; Zhang Xiaoyang; Wang Zeyan; Jiang Minhua

    2009-01-01

    Metastable Bi 20 TiO 32 samples were synthesized by a high-temperature quenching method using α-Bi 2 O 3 and anatase TiO 2 as raw materials. The photocatalytic activity of the as-prepared samples was measured with the photodegradation of methyl orange at room temperature under visible light irradiation. The Bi 20 TiO 32 samples exhibited good absorption in the visible light region with a band gap of about 2.38 eV and the band structure of Bi 20 TiO 32 was studied. Photodegradation against methyl orange was much better than α-Bi 2 O 3 prepared by the same way. The photocatalytic activity of Bi 20 TiO 32 samples is supposed to be associated with the hybridized Bi 6s and O 2p orbitals. In addition, the dispersive characteristic of Bi 6s orbital in the hybridized valence band facilitates the mobility of the photogenerated carriers and hampers their recombination. - Graphical abstract: Metastable Bi 20 TiO 32 samples were successfully synthesized by a quenching process. Photodegradation against methyl orange showed high visible-light activity and it was supposed to be associated with its corresponding band structure.

  6. Review Article

    African Journals Online (AJOL)

    2012-09-27

    Sep 27, 2012 ... rationalism vs. irrationalism and emancipation vs. deconstruction. This article tries to critically .... conceptions of time, limitations of modern culture, exaggerated rationality ... and organizational mastery of empirical processes” ...

  7. Research Article

    African Journals Online (AJOL)

    2016-06-13

    Jun 13, 2016 ... emerging drug-resistant pathogens in research programme around the world. This article reviews the history of antibiotics, different types of antibiotics, .... of the plasma membrane; these changes result in the loss of important ...

  8. Original Article

    African Journals Online (AJOL)

    Administratör

    Original Article. Prevalence of Gall Bladder Stones among Type 2 Diabetic ... Increasing age, female gender, overweight, familial history of the disease and type 2 diabetes mellitus is all associated ... GBS development in diabetics. An Italian ...

  9. Communications article

    KAUST Repository

    Fariborzi, Hossein

    2017-01-01

    Seamless, covert communications using a communications system integrated or incorporated within an article of clothing is described. In one embodiment, the communications system is integrated or incorporated into a shoe insole and includes a haptic

  10. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    User

    (with and without its frailty) in Estimating Survival Time of Patients with Colorectal Cancer ..... ACKNOWLEDGMENT. This article is a part of research project approved ... rectal cancer survival trends in Norway 1958. –1997. European Journal of ...

  11. Research Article

    African Journals Online (AJOL)

    2016-06-18

    Jun 18, 2016 ... In the present article, aspect oriented programming and design patterns are ... works have been devoted to solve the problems it is going to face. ... utilized as an architecture concept in C++ language and then the book GOF ...

  12. Silica supported TiO{sub 2} nanostructures for highly efficient photocatalytic application under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Pal, A.; Jana, T.K.; Chatterjee, K., E-mail: kuntal2k@gmail.com

    2016-04-15

    Highlights: • Synthesis of silica–titania nanocomposite by simple and facile chemical route and characterization of the materials. • Excellent catalytic activity on organic pollutant methylene blue under the visible light irradiation. • Photocatalytic rate is much higher than commercial P25 TiO{sub 2} catalyst powder. • The higher activity is attributed to the special structure and synergistic effect of the materials which has immense application potential. - Abstract: Titanium dioxide decorated silica nanospheres have been synthesized by a simple wet chemical approach. X-ray diffraction, electron microscopy and energy dispersive X-ray analysis revealed that anatase phase of TiO{sub 2} nanostructures, with exposed {0 0 1} and {1 0 1} facets, are anchored onto the amorphous silica spheres of ∼60 nm diameter. The photocatalytic activity of the sample under visible light irradiation was examined. It is found that photocatalytic efficiency of the material is better than commercial P25 TiO{sub 2} photocatalyst and the result is attributed to the unique synergistic effect of SiO{sub 2}–TiO{sub 2} nanocomposite structure resulting enhanced charge separation and charge transfer.

  13. Simple method of preparing nitrogen - doped nanosized TiO2 powders of high photocatalytic activity under visible light

    International Nuclear Information System (INIS)

    Nguyen Van Hung; Dang Thi Thanh Le

    2014-01-01

    Nitrogen-doped nanosized TiO 2 powders were prepared by a simple thermal treatment method of the mixture of titanium dioxide and urea. The prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (UV-Vis-DRS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the crystal structure of N-TiO 2 was a mixture of anatase and rutile phases, and the average particle size was 31 nm calculated from XRD results. The UV-vis spectra indicate an increase in absorption of visible light when compared to undoped TiO 2 . The photocatalytic activity of nitrogen-doped TiO 2 powder was evaluated by the decomposition of methylene blue under visible light irradiation. And it was found that nitrogen-doped TiO 2 powders exhibited much higher photocatalytic activity than undoped TiO 2 . Moreover, the study also showed that, the doping N atoms improve the growth of the TiO 2 crystal and phase transformation. (author)

  14. Nano scale Devices for Rectification of High Frequency Radiation from the Infrared through the Visible: A New Approach

    International Nuclear Information System (INIS)

    Miskovsky, N.M.; Cutler, P.H.; Miskovsky, N.M.; Cutler, P.H.; Lerne, P.B.; Mayer, A.; Weiss, B.L.; Willis, B.; Sullivan, T.E.

    2012-01-01

    We present a new and viable method for optical rectification. This approach has been demonstrated both theoretically and experimentally and is the basis fot the development of devices to rectify radiation through the visible. This technique for rectification is based not on conventional material or temperature asymmetry as used in MIM (metal/insulator/metal) or Schottky diodes, but on a purely sharp geometric property of the antenna. This sharp tip or edge with a collector anode constitutes a tunnel junction. In these devices the rectenna (consisting of the antenna and the tunnel junction) acts as the absorber of the incident radiation and the rectifier. Using current nano fabrication techniques and the selective atomic layer deposition (ALD) process, junctions of 1?nm can be fabricated, which allow for rectification of frequencies up to the blue portion of the spectrum. To assess the viability of our approach, we review the development of nano antenna structures and tunnel junctions capable of operating in the visible region. In addition, we review the detailed process of rectification and present methodologies for analysis of diode data. Finally, we present operational designs for an optical rectenna and its fabrication and discuss outstanding problems and future work.

  15. Nanoscale Devices for Rectification of High Frequency Radiation from the Infrared through the Visible: A New Approach

    Directory of Open Access Journals (Sweden)

    N. M. Miskovsky

    2012-01-01

    Full Text Available We present a new and viable method for optical rectification. This approach has been demonstrated both theoretically and experimentally and is the basis fot the development of devices to rectify radiation through the visible. This technique for rectification is based not on conventional material or temperature asymmetry as used in MIM (metal/insulator/metal or Schottky diodes, but on a purely sharp geometric property of the antenna. This sharp “tip” or edge with a collector anode constitutes a tunnel junction. In these devices the rectenna (consisting of the antenna and the tunnel junction acts as the absorber of the incident radiation and the rectifier. Using current nanofabrication techniques and the selective atomic layer deposition (ALD process, junctions of 1 nm can be fabricated, which allow for rectification of frequencies up to the blue portion of the spectrum. To assess the viability of our approach, we review the development of nanoantenna structures and tunnel junctions capable of operating in the visible region. In addition, we review the detailed process of rectification and present methodologies for analysis of diode data. Finally, we present operational designs for an optical rectenna and its fabrication and discuss outstanding problems and future work.

  16. Diffusion Patterns in Convergence among High-Technology Industries: A Co-Occurrence-Based Analysis of Newspaper Article Data

    Directory of Open Access Journals (Sweden)

    Hyeokseong Lee

    2016-10-01

    Full Text Available Firms in high-technology industries have faced great technological and market uncertainty and volatility in the past few decades. In order to be competitive and sustainable in this environment, firms have been pursuing technological innovation, product differentiation, vertical integration, and alliances, which eventually drive industry convergence, defined as the process of blurring boundaries between previously distinct industries. Although industry convergence has greatly affected industrial structure and the economy, little research has investigated this phenomenon, especially its diffusion patterns; thus, it is still unclear which industries are converging more rapidly or have a higher potential for convergence. This paper explores these issues by investigating industry convergence in U.S. high-technology industries, using a large set of newspaper articles from 1987 to 2012. We perform a co-occurrence-based analysis to obtain information on industry convergence and estimate its diffusion patterns using an internal-influence logistic model. We find heterogeneous diffusion patterns, depending on convergent-industry pairs and their wide dispersion. In addition, we find that the potential degree of industry convergence is significantly negatively associated with its growth rate, which indicates that a great deal of time will be required for industry convergence between high-technology industries with this high potential to achieve a high degree of convergence.

  17. A highly uniform ZnO/NaTaO{sub 3} nanocomposite: Enhanced self-sensitized degradation of colored pollutants under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Guanjie; Tang, Changhe [School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, Inner Mongolia, 010021 (China); Zhang, Bo [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei, 430072 (China); Zhao, Lanxiao; Su, Yiguo [School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, Inner Mongolia, 010021 (China); Wang, Xiaojing, E-mail: wang_xiao_jing@hotmail.com [School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, Inner Mongolia, 010021 (China)

    2015-10-25

    In this study, a highly uniform ZnO/NaTaO{sub 3} composite was prepared via simple hydrothermal synthesis. XRD confirmed the composite was constructed by pure cubic phase of NaTaO{sub 3} and hexagonal phase of ZnO. SEM analysis showed that as-prepared ZnO/NaTaO{sub 3} shaped as an irregular ginger with an obviously smaller size than that of pure ZnO without obvious agglomeration. EDS mapping demonstrated that the four elements (Na, Ta, O, Zn) in the composite were very uniformly distributed. The photocatalytic behaviors of as-prepared composites were studied in the degradation of methylene blue both under UV and visible irradiation. The bare ZnO showed the highest activity with 99.8% methylene blue (MB) photodegraded in 70 min under UV light irradiation whereas 94% photodegraded rate was achieved for ZnO/NaTaO{sub 3}. More importantly, the uniform composite of ZnO/NaTaO{sub 3} exhibited effective degradation of methylene blue under visible light which can be attributed to the well dyes adsorption abilities and the high efficiency of electron separation, induced by the synergistic effect between ZnO and NaTaO{sub 3}. It is confirmed the dye rather than a semiconductor is excited under visible light irradiation and a self-sensitized photocatalytic mechanism was then proposed based on the experimental results. - Graphical abstract: Visible light photocatalytic activity of ZnO/NaTaO{sub 3} and proposed schematic of self-sensitization directed photogradation of MB. - Highlights: • Highly uniform ZnO/NaTaO{sub 3} photocatalysts were fabricated by hydrothermal method. • ZnO/NaTaO{sub 3} composite exhibited effective degradation of MB under visible light. • ZnO/NaTaO{sub 3} composite effectively promoted dye adsorption and electrons separation. • A self-sensitized photocatalytic mechanism was proposed for the degradation of dye.

  18. Ultrawide spectral broadening and compression of single extremely short pulses in the visible, uv-vuv, and middle infrared by high-order stimulated Raman scattering

    International Nuclear Information System (INIS)

    Kalosha, V. P.; Herrmann, J.

    2003-01-01

    We present the results of a comprehensive analytical and numerical study of ultrawide spectral broadening and compression of isolated extremely short visible, uv-vuv and middle infrared (MIR) pulses by high-order stimulated Raman scattering in hollow waveguides. Spectral and temporal characteristics of the output pulses and the mechanism of pulse compression using dispersion of the gas filling and output glass window are investigated without the slowly varying envelope approximation. Physical limitations due to phase mismatch, velocity walk off, and pump-pulse depletion as well as improvements through the use of pump-pulse sequences and dispersion control are studied. It is shown that phase-locked pulses as short as ∼2 fs in the visible and uv-vuv, and 6.5 fs in the MIR can be generated by coherent scattering in impulsively excited Raman media without the necessity of external phase control. Using pump-pulse sequences, shortest durations in the range of about 1 fs for visible and uv-vuv probe pulses are predicted

  19. BiVO4 /N-rGO nano composites as highly efficient visible active photocatalyst for the degradation of dyes and antibiotics in eco system.

    Science.gov (United States)

    Appavu, Brindha; Thiripuranthagan, Sivakumar; Ranganathan, Sudhakar; Erusappan, Elangovan; Kannan, Kathiravan

    2018-04-30

    Herein, we report the synthesis of novel nitrogen doped reduced graphene oxide/ BiVO 4 photo catalyst by single step hydrothermal method. The physicochemical properties of the catalysts were characterized using XRD, N 2 adsorption-desorption, Raman, XPS, SEM TEM, DRS-UV and EIS techniques. The synthesized catalysts were tested for their catalytic activity in the photo degradation of some harmful textile dyes (methylene blue & congo red) and antibiotics (metronidazole and chloramphenicol) under visible light irradiation. Reduced charge recombination and enhanced photocatalytic activity were observed due to the concerted effect between BiVO 4 and nitrogen-rGO. The degradation efficiency of BiVO 4 /N-rGO in the degradation of CR and MB was remarkably high i.e 95% and 98% under visible light irradiation. Similarly 95% of MTZ and 93% of CAP were degraded under visible light irradiation. HPLC studies implied that both the dyes and antibiotics were degraded to the maximum extent. The plausible photocatalytic mechanism on the basis of experimental results was suggested. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Facile fabrication of Ag3VO4/attapulgite composites for highly efficient visible light-driven photodegradation towards organic dyes and tetracycline hydrochloride

    Science.gov (United States)

    Luo, Yuting; Luo, Jie; Duan, Guorong; Liu, Xiaoheng

    2017-12-01

    An efficient one-dimensional attapulgite (ATP)-based photocatalyst, Ag3VO4/ATP nanocomposite, was fabricated by a facile deposition precipitation method with well-dispersed Ag3VO4 nanoparticles anchored on the surface of natural ATP fibers. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectroscopy (UV-vis DRS) were employed to investigate the morphologies, structure, and optical property of the prepared photocatalysts. The photocatalytic experiments indicated that the Ag3VO4/ATP nanocomposites exhibited enhanced visible light-driven photocatalytic activity towards the degradation of rhodamine B (RhB), methyl orange (MO), and tetracycline hydrochloride (TCH), of which the 20 wt% Ag3VO4/ATP sample showed superb photocatalytic performance. As demonstrated by N2 adsorption-desorption, photocurrent measurements, electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) spectra analyses, the improved photocatalytic activity arose from the enlarged surface area, the facilitated charge transfer, and the suppressed recombination of photogenerated charge carriers in Ag3VO4/ATP system. Furthermore, radical scavengers trapping experiments and recycling tests were also conducted. This work gives a new insight into fabrication of highly efficient, stable, and cost-effective visible light-driven photocatalyst for practical application in wastewater treatment and environmental remediation.

  1. CdS nanoparticles/CeO{sub 2} nanorods composite with high-efficiency visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    You, Daotong; Pan, Bao; Jiang, Fan; Zhou, Yangen; Su, Wenyue, E-mail: suweny@fzu.edu.cn

    2016-02-15

    Graphical abstract: Coupling CdS with CeO{sub 2} can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2} NRs as the photoinduced electrons on the conduction band of CdS are transfered to the conduction band of CeO{sub 2}. - Highlights: • Coupling CdS can effectively improve the light-harvesting ability of wide-band gap CeO{sub 2}. • CdS/CeO{sub 2} composites show high photocatalytic activity under visible light irradiation. • The mechanism of photocatalytic H{sub 2} evolution over CdS/CeO{sub 2} was proposed. - Abstract: Different mole ratios of CdS nanoparticles (NPs)/CeO{sub 2} nanorods (NRs) composites with effective contacts were synthesized through a two-step hydrothermal method. The crystal phase, microstructure, optical absorption properties, electrochemical properties and photocatalytic H{sub 2} production activity of these composites were investigated. It was concluded that the photogenerated charge carriers in the CdS NPs/CeO{sub 2} NRs composite with a proper mole ratio (1:1) exhibited the longest lifetime and highest separation efficiency, which was responsible for the highest H{sub 2}-production rate of 8.4 mmol h{sup −1} g{sup −1} under visible-light irradiation (λ > 420 nm). The superior photocatalytic H{sub 2} evolution properties are attributed to the transfer of visible-excited electrons of CdS NPs to CeO{sub 2} NRs, which can effectively extend the light absorption range of wide-band gap CeO{sub 2} NRs. This work provides feasible routes to develop visible-light responsive CeO{sub 2}-based nanomaterial for efficient solar utilization.

  2. In situ synthesis of CdS decorated titanate nanosheets with highly efficient visible-light-induced photoactivity

    International Nuclear Information System (INIS)

    Liu, Zhi; Fang, Pengfei; Liu, Fuwei; Zhang, Yupeng; Liu, Xinzhao; Lu, Dingze; Li, Delong; Wang, Shaojie

    2014-01-01

    Appropriately dispersed CdS nanoparticles were intimately embedded into titanate nanosheets (TNS) through ion-exchange and in situ sulfurization process. The sheet-like intermediates of titanate during the transforming process into nanotubes were firstly used as substrate for the decoration of CdS nanoparticles, and the synthesis route was achieved by ion-exchange process between titanate precursor and Cd 2+ ions solution, and the following sulfuration process by using Na 2 S solutions. The catalytic activity of the photocatalyst was investigated by photodegradation of Rhodamine B under visible light irradiation. With an optimal Cd/Ti molar ratio of 15%, the CdS/TNS composite exhibits the highest photocatalytic performance, which is approximately 5.4 times greater than that of pure TNS. The mechanism of the separation behavior of the photogenerated charges was also discussed.

  3. High sensitivity ethanol gas sensor based on Sn - doped ZnO under visible light irradiation at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peishuo; Pan, Guofeng; Zhang, Bingqiang; Zhen, Jiali; Sun, Yicai, E-mail: pgf@hebut.edu.cn [Institute of Microelectronic, Hebei University of Technology, Tianjin (China)

    2014-07-15

    Pure ZnO and 5at%, 7at%, 9at% Sn - doped ZnO materials are prepared by the chemical co - precipitation method. They were annealed by furnace at temperature range of 300 - 700ºC in air for 1h. The ZnO materials are characterized by X - ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the Sn - doped ZnO materials appear rough porous structures. The maximum sensitivity can be achieved by doping the amount of 7 at%. It has much better sensing performance towards ethanol vapor under visible light irradiation. The response and recovery time are ~1s and ~5s, respectively. The mechanism for the improvement in the sensing properties can be explained with the surface adsorption theory and the photoactivation theory. (author)

  4. Controllable Fabrication of Ordered Mesoporous Bi2WO6 and Its High Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Xueming Dang

    2014-01-01

    Full Text Available Ordered mesoporous Bi2WO6 was fabricated by nanocasting technique using SBA-15 as the template. The effect of the dosage of SBA-15 on the formation of the ordered structure and the photocatalytic ability of mesoporous Bi2WO6 was discussed. It was confirmed that the ordered mesoporous structure was obtained as the dosage of SBA-15 was 0.3 g. It was found that, compared to Bi2WO6, the RhB degradation rate with ordered mesoporous Bi2WO6 was enhanced under visible light (λ>400 nm by the photocatalytic measurements. The enhanced photocatalytic performance of ordered mesoporous Bi2WO6 was attributed to its particular ordered mesoporous structure which could increase the light-harvesting efficiency, reduce the recombination of the photogenerated charge carriers, and promote the surface reaction.

  5. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Illnesses of Herod the Great. Francois P Retief, Johan F G Cilliers. Herod the Great, ldumean by birth, was king ofthe Jews from 40 to 4 BC. An able statesman, builder and warrior, he ruthlessly stamped out all perceived opposition to his rule. His last decade was characterised by vicious strife within ...

  6. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. McCarthy D, Amos A, Zimmet P. The rising global burden of diabetes and its complications: estimates and projections to the year 2010. Diabet Med 1997; 14: suppl 5, Sl-585. 2. Zgibor JC, Songer TJ, Kelsey SF, et al. The association of diabetes specialist care with health care practices ...

  7. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. Cost to patients of obtaining treatment for HIV/AIDS in. South Africa. Sydney Rosen, Mpefe Ketlhapile, Ian Sanne, Mary Bachman DeSilva. Background. South Africa is providing antiretroviral (ARV) drugs for HIV I AIDS free of charge in order to increase access for poorer patients and promote ...

  8. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES could be chosen to link to action policy decisions. In the. Integrated Management of Childhood Illness (IMCI) programme, such a screening test would also remind the health provider to prescribe an iron tonic and to emphasise the importance of a balanced diet. A potential disadvantage of copper ...

  9. SERIES ARTICLES

    Indian Academy of Sciences (India)

    Microscale Experiments in Chemistry - The Need of the New Millenium. Experiments Which Bring Theory Closer to Laboratories. Shriniwas L Kelkar and Dilip D Dhavale. GENERAL ARTICLES. Chandra's X-ray Vision. K P Singh. Space-Filling Curves. R C Mittal. DNA Chip. The Whats, the Whys and the Hows. Bhismadev ...

  10. Original Article

    African Journals Online (AJOL)

    Arab Journal of Nephrology and Transplantation. 2013 Sep;6(3):153-60. Original Article. AJNT. Abstract. Introduction: Dense Deposit Disease (DDD) is a devastating renal disease that leads to renal failure within. 10 years of diagnosis in about half of affected patients. In this study, we evaluated the relative prevalence and.

  11. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    User

    One of the concerns among mothers for delivery is labor pain. There are various ... Journal of Medical and Biomedical Sciences (2017) 6(2): 11-16. © UDS Publishers ... ORIGINAL ARTICLE ..... effective than a placebo during the first stage of.

  12. Research Article

    African Journals Online (AJOL)

    SAMSUNG

    2016-06-05

    Jun 5, 2016 ... for civil engineers (in terms of gravity and lateral load) in developed countries. Despite the relatively significant growth of LSF structures during the last decade in our country, the studies in this field have been still done neither in our country nor in abroad. In this article, we try to study LSF structures from the ...

  13. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    ORIGINAL ARTICLES. References. 1. UNAIDS. Report on the Global HTV/AIDS Epidemic. Geneva: June 2000. 2. Connor E..\\1, Sperling RS, Gelber R. et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovu dine treatment. N Eng! J Med 1994; 331:1173-1180. 3. Undegren ML ...

  14. Research Article

    African Journals Online (AJOL)

    pc

    2018-05-01

    May 1, 2018 ... In addition, the accounting information system plays a major role in providing ... being studied, which we will review in this article. the impact of information technology ... taking into account the form of traditional controls and roles. in other words ... among sectors and individuals. the use of e-mail, the internal ...

  15. Download article

    African Journals Online (AJOL)

    user

    tions made in this article about outer texts in an electronic sign language dictionary serve as part of a complete concept model suggested specifically for the De la Bat School for the Deaf in Worcester,. South Africa (Fourie 2013). The purpose of the proposed dictionary is to give the learners of the De la Bat School electronic ...

  16. Review Article

    African Journals Online (AJOL)

    2012-09-20

    Sep 20, 2012 ... same years indicating a yield gain from extensive farming system. The production ... capacity to process the sesame and/or oil seeds in the country. Article History: ..... on: Area and production of crops (private peasant holdings ...

  17. Review Article

    African Journals Online (AJOL)

    2007-12-02

    Dec 2, 2007 ... Introduction. What prompted this review article is because of the wrong notion that the only standard abdominal incision is the midline incision. Cases have been seen in which an abdominal incision extends from the xyphoid process to the symphysis pubis just to remove a perforated appendix! The reason ...

  18. Visible-light active thin-film WO3 photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    Directory of Open Access Journals (Sweden)

    Nobuto Oka

    2015-10-01

    Full Text Available A process based on reactive gas flow sputtering (GFS for depositing visible-light active photocatalytic WO3 films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO3 films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH3CHO under visible light irradiation. The decomposition time for 60 ppm of CH3CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO3 films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH3CHO.

  19. Hierarchical architectures of ZnS–In2S3 solid solution onto TiO2 nanofibers with high visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Liu, Chengbin; Meng, Deshui; Li, Yue; Wang, Longlu; Liu, Yutang; Luo, Shenglian

    2015-01-01

    Graphical abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution onto TiO 2 nanofibers was fabricated. The hierarchical heterostructures exhibit high visible light photocatalytic activity and outstanding recycling performance. - Highlights: • Novel hierarchical heterostructure of TiO 2 @ZnS–In 2 S 3 solid solution. • Efficient inhibition of ZnS–In 2 S 3 solid solution aggregation. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique hierarchical architecture of ZnS–In 2 S 3 solid solution nanostructures onto TiO 2 nanofibers (TiO 2 @ZnS–In 2 S 3 ) has been successfully fabricated by simple hydrothermal method. The ZnS–In 2 S 3 solid solution nanostructures exhibit a diversity of morphologies: nanosheet, nanorod and nanoparticle. The porous TiO 2 nanofiber templates effectively inhibit the aggregation growth of ZnS–In 2 S 3 solid solution. The formation of ZnS–In 2 S 3 solid solution is proved by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) and the intimate contact between TiO 2 nanofibers and ZnS–In 2 S 3 solid solution favors fast transfer of photogenerated electrons. The trinary TiO 2 @ZnS–In 2 S 3 heterostructures exhibit high adsorption capacity and visible light photocatalytic activity for the degradation of rhodamine B dye (RhB), remarkably superior to pure TiO 2 nanofibers or binary structures (ZnS/TiO 2 nanofibers, In 2 S 3 /TiO 2 nanofibers and ZnS–In 2 S 3 solid solution). Under visible light irradiation the RhB photocatalytic degradation rate over TiO 2 @ZnS–In 2 S 3 heterostructures is about 16.7, 12.5, 6.3, 5.9, and 2.2 times that over pure TiO 2 nanofibers, ZnS nanoparticles, In 2 S 3 /TiO 2 nanofibers, ZnS/TiO 2 nanofibers, and ZnS-In 2 S 3 solid solution, respectively. Furthermore, the TiO 2 @ZnS–In 2 S 3 heterostructures show highly stable recycling performance

  20. Highly efficient visible-light driven photochromism: developments towards a solid-state molecular switch operating through a triplet-sensitised pathway.

    Science.gov (United States)

    Brayshaw, Simon K; Schiffers, Stephanie; Stevenson, Anna J; Teat, Simon J; Warren, Mark R; Bennett, Robert D; Sazanovich, Igor V; Buckley, Alastair R; Weinstein, Julia A; Raithby, Paul R

    2011-04-11

    We introduce a new highly efficient photochromic organometallic dithienylethene (DTE) complex, the first instance of a DTE core symmetrically modified by two Pt(II) chromophores [Pt(PEt(3))(2)(C≡C)(DTE)(C≡C)Pt(PEt(3))(2)Ph] (1), which undergoes ring-closure when activated by visible light in solvents of different polarity, in thin films and even in the solid state. Complex 1 has been synthesised and fully photophysically characterised by (resonance) Raman and transient absorption spectroscopy complemented by calculations. The ring-closing photoconversion in a single crystal of 1 has been followed by X-ray crystallography. This process occurs with the extremely high yield of 80%--considerably outperforming the other DTE derivatives. Remarkably, the photocyclisation of 1 occurs even under visible light (>400 nm), which is not absorbed by the non-metallated DTE core HC≡C(DTE)C≡CH (2) itself. This unusual behaviour and the high photocyclisation yields in solution are attributed to the presence of a heavy atom in 1 that enables a triplet-sensitised photocyclisation pathway, elucidated by transient absorption spectroscopy and DFT calculations. The results of resonance Raman investigation confirm the involvement of the alkynyl unit in the frontier orbitals of both closed and open forms of 1 in the photocyclisation process. The changes in the Raman spectra upon cyclisation have permitted the identification of Raman marker bands, which include the acetylide stretching vibration. Importantly, these bands occur in the spectral region unobstructed by other vibrations and can be used for non-destructive monitoring of photocyclisation/photoreversion processes and for optical readout in this type of efficiently photochromic thermally stable systems. This study indicates a strategy for generating efficient solid-state photoswitches in which modification of the Pt(II) units has the potential to tune absorption properties and hence operational wavelength across the visible

  1. Protective articles

    International Nuclear Information System (INIS)

    Wardley, R.B.

    1983-01-01

    This patent specification describes an article affording protection against radiation, and especially against X-rays comprising at least one flexible layer of lead filled material in an envelope of, or sandwiched between two layers of a knitted, woven or non-woven fabric preferably of synthetic fibrous material, carrying on its outer surface a coating of flexible polyurethane. The outer fabric provides a resilient, extremely tough and cut resistant covering for the relatively soft lead filled material. (author)

  2. Facile synthesis of graphitic C3N4 nanoporous-tube with high enhancement of visible-light photocatalytic activity

    Science.gov (United States)

    Zhao, Ruiru; Gao, Jianping; Mei, Shunkang; Wu, Yongli; Wang, Xiaoxue; Zhai, Xiangang; Yang, Jiangbing; Hao, Chaoyue; Yan, Jing

    2017-12-01

    A simple and convenient method was used to synthesize a graphitic carbon nitride (g-C3N4) nanoporous-tube by using SiO2 nanoparticles as pore formers. The structure of the g-C3N4 nanoporous-tube was characterized by the SEM and TEM images. Taking photodegradation of RhB as an example, the photocatalytic activity of the as-prepared g-C3N4 nanoporous-tube was investigated. It can photodegrade 90% RhB in 40 min under visible-light irradiation and obtain a k value of 0.04491 min-1, which is 8.16 times that of bulk g-C3N4, 3.09 times that of tubular g-C3N4 and 1.48 times that of tubular g-C3N4-SiO2. The significant enhancement in photocatalytic efficiency is due to the edge effect of the pores and the special structure of the tubes. In addition, the possible mechanism of photocatalytic degradation of RhB was also proposed based on the trapping experiment of active species, which indicated that the superoxide radicals ({{{{O}}}2}\\bullet -) and the holes (h +) were the main reactive species in this photocatalyst. This work may open up a new idea of innovation in g-C3N4 structure and inspire its follow-up study.

  3. Construction of Ag/AgCl nanostructures from Ag nanoparticles as high-performance visible-light photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Fan; Liu, Dongzhi; Wang, Tianyang; Li, Wei [Tianjin University, School of Chemical Engineering and Technology (China); Hu, Wenping [Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering (China); Zhou, Xueqin, E-mail: zhouxueqin@tju.edu.cn [Tianjin University, School of Chemical Engineering and Technology (China)

    2016-11-15

    A combined strategy of in situ oxidation and assembly is developed to prepare Ag/AgCl nanospheres and nanocubes from Ag nanoparticles under room temperature. It is a new facile way to fabricate Ag/AgCl with small sizes and defined morphologies. Ag/AgCl nanospheres with an average size of 80 nm were achieved without any surfactants, while Ag/AgCl nanocubes with a mean edge length of 150 nm were obtained by introduction of N-dodecyl-N,N-dimethyl-2-ammonio-acetate. The possible formation mechanism involves the self-assembly of AgCl nanoparticles, Ostwald ripening and photoreduction of Ag{sup +} into Ag{sup 0} by the room light. The as-prepared Ag/AgCl nanospheres and nanocubes exhibit excellent photocatalytic activity and stability toward degradation of organic pollutants under visible-light irradiation. It is demonstrated that Ag/AgCl nanocubes display enhanced photocatalytic activity in comparison with Ag/AgCl nanospheres due to the more efficient charge transfer. This work may pave an avenue to construct various functional materials via the assembly strategy using nanoparticles as versatile building blocks.

  4. Visible-light-induced hydrogen production over Pt-Eosin Y catalysts with high surface area silica gel as matrix

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaojie [State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, The Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate University of the Chinese Academy of Sciences, Beijing 100101 (China); Jin, Zhiliang; Li, Shuben; Lu, Gongxuan [State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, The Chinese Academy of Sciences, Lanzhou 730000 (China); Li, Yuexiang [Department of Chemistry, Nanchang University, Nanjing Road 245, Nanchang, 330047 (China)

    2007-03-30

    A new system for the production of hydrogen, constructed using silica gel as a matrix, Eosin Y as a photosensitizer, and Pt as a cocatalyst, has been reported. It was found that the rate of photosensitized hydrogen evolution in the presence of silica gel is enhanced about 10-fold relative to the homogeneous phase, i.e. in the absence of silica gel. The pH value of the solution and the concentration of Eosin Y have remarkable effects on the rate of hydrogen evolution. The optimal pH and concentration of Eosin Y are 7 and 3.60 x 10{sup -4} mol dm{sup -3} (E/S = 1/3) to 7.24 x 10{sup -4} mol dm{sup -3} (E/S = 1/1), respectively. Triethanolamine (TEOA) as an electron donor, the rate of hydrogen evolution and the apparent quantum efficiency in the silica gel system under visible-light irradiation ({lambda} {>=} 420 nm) can reach about 43 {mu}mol h{sup -1} and 10.4%, respectively. In addition, the roles of silica gel, Pt and TEOA, respectively; and the probable mechanism of photosensitized hydrogen evolution have been discussed. (author)

  5. Visible-light-induced hydrogen production over Pt-Eosin Y catalysts with high surface area silica gel as matrix

    Science.gov (United States)

    Zhang, Xiaojie; Jin, Zhiliang; Li, Yuexiang; Li, Shuben; Lu, Gongxuan

    A new system for the production of hydrogen, constructed using silica gel as a matrix, Eosin Y as a photosensitizer, and Pt as a cocatalyst, has been reported. It was found that the rate of photosensitized hydrogen evolution in the presence of silica gel is enhanced about 10-fold relative to the homogeneous phase, i.e. in the absence of silica gel. The pH value of the solution and the concentration of Eosin Y have remarkable effects on the rate of hydrogen evolution. The optimal pH and concentration of Eosin Y are 7 and 3.60 × 10 -4 mol dm -3 (E/S = 1/3) to 7.24 × 10 -4 mol dm -3 (E/S = 1/1), respectively. Triethanolamine (TEOA) as an electron donor, the rate of hydrogen evolution and the apparent quantum efficiency in the silica gel system under visible-light irradiation (λ ≥ 420 nm) can reach about 43 μmol h -1 and 10.4%, respectively. In addition, the roles of silica gel, Pt and TEOA, respectively; and the probable mechanism of photosensitized hydrogen evolution have been discussed.

  6. Highly efficient visible light photocatalytic reduction of CO2 to hydrocarbon fuels by Cu-nanoparticle decorated graphene oxide.

    Science.gov (United States)

    Shown, Indrajit; Hsu, Hsin-Cheng; Chang, Yu-Chung; Lin, Chang-Hui; Roy, Pradip Kumar; Ganguly, Abhijit; Wang, Chen-Hao; Chang, Jan-Kai; Wu, Chih-I; Chen, Li-Chyong; Chen, Kuei-Hsien

    2014-11-12

    The production of renewable solar fuel through CO2 photoreduction, namely artificial photosynthesis, has gained tremendous attention in recent times due to the limited availability of fossil-fuel resources and global climate change caused by rising anthropogenic CO2 in the atmosphere. In this study, graphene oxide (GO) decorated with copper nanoparticles (Cu-NPs), hereafter referred to as Cu/GO, has been used to enhance photocatalytic CO2 reduction under visible-light. A rapid one-pot microwave process was used to prepare the Cu/GO hybrids with various Cu contents. The attributes of metallic copper nanoparticles (∼4-5 nm in size) in the GO hybrid are shown to significantly enhance the photocatalytic activity of GO, primarily through the suppression of electron-hole pair recombination, further reduction of GO's bandgap, and modification of its work function. X-ray photoemission spectroscopy studies indicate a charge transfer from GO to Cu. A strong interaction is observed between the metal content of the Cu/GO hybrids and the rates of formation and selectivity of the products. A factor of greater than 60 times enhancement in CO2 to fuel catalytic efficiency has been demonstrated using Cu/GO-2 (10 wt % Cu) compared with that using pristine GO.

  7. High-precision approach to localization scheme of visible light communication based on artificial neural networks and modified genetic algorithms

    Science.gov (United States)

    Guan, Weipeng; Wu, Yuxiang; Xie, Canyu; Chen, Hao; Cai, Ye; Chen, Yingcong

    2017-10-01

    An indoor positioning algorithm based on visible light communication (VLC) is presented. This algorithm is used to calculate a three-dimensional (3-D) coordinate of an indoor optical wireless environment, which includes sufficient orders of multipath reflections from reflecting surfaces of the room. Leveraging the global optimization ability of the genetic algorithm (GA), an innovative framework for 3-D position estimation based on a modified genetic algorithm is proposed. Unlike other techniques using VLC for positioning, the proposed system can achieve indoor 3-D localization without making assumptions about the height or acquiring the orientation angle of the mobile terminal. Simulation results show that an average localization error of less than 1.02 cm can be achieved. In addition, in most VLC-positioning systems, the effect of reflection is always neglected and its performance is limited by reflection, which makes the results not so accurate for a real scenario and the positioning errors at the corners are relatively larger than other places. So, we take the first-order reflection into consideration and use artificial neural network to match the model of a nonlinear channel. The studies show that under the nonlinear matching of direct and reflected channels the average positioning errors of four corners decrease from 11.94 to 0.95 cm. The employed algorithm is emerged as an effective and practical method for indoor localization and outperform other existing indoor wireless localization approaches.

  8. One novel material with high visible-light activity: hexagonal Cu flakelets embedded in the petals of BiOBr flower-nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuling; Wu, Qingsheng, E-mail: qswu@tongji.edu.cn [Tongji University, School of Chemical Science and Engineering (China)

    2017-02-15

    The novel BiOBr flower-nanospheres embedded by hexagonal Cu have been synthesized successfully through an ingenious design, by one-step solvothermal process with two kinds of bifunctional reagents, namely, 1-hexadecyl-3-methylimidazolium bromide [C{sub 16}min]Br and ethylene glycol (EG). Pure BiOBr flower-sphere has been synthesized by solvothermal process. In the result of Cu-embedded BiOBr flower-nanospheres, the diameter of the flower-sphere is about 1.5 μm (±0.1) with hexagon copper about 10-nm side length in the petals of BiOBr flower-nanospheres. The Cu-embedded BiOBr composites exhibit high photocatalytic activity than pure BiOBr, which was investigated by the degradation of rhodamine B solution (RhB) and methyl orange solution (MO) under simulative visible-light irradiation. Nearly 100 and 80% of conversion can be achieved from the degradation of RhB and MO after 1.5 h, respectively. The high ability of photocatalysis may be attributed to the narrow-band-gap semiconductor BiOBr, high electron transportation of copper, and the coupling of Cu and BiOBr. It can lead to the strong absorption in the visible region and improve the separation of photogenerated electron–hole pairs.

  9. Well-crystalline porous ZnO-SnO2 nanosheets: an effective visible-light driven photocatalyst and highly sensitive smart sensor material.

    Science.gov (United States)

    Lamba, Randeep; Umar, Ahmad; Mehta, S K; Kansal, Sushil Kumar

    2015-01-01

    This work demonstrates the synthesis and characterization of porous ZnO-SnO2 nanosheets prepared by the simple and facile hydrothermal method at low-temperature. The prepared nanosheets were characterized by several techniques which revealed the well-crystallinity, porous and well-defined nanosheet morphology for the prepared material. The synthesized porous ZnO-SnO2 nanosheets were used as an efficient photocatalyst for the photocatalytic degradation of highly hazardous dye, i.e., direct blue 15 (DB 15), under visible-light irradiation. The excellent photocatalytic degradation of prepared material towards DB 15 dye could be ascribed to the formation of ZnO-SnO2 heterojunction which effectively separates the photogenerated electron-hole pairs and possess high surface area. Further, the prepared porous ZnO-SnO2 nanosheets were utilized to fabricate a robust chemical sensor to detect 4-nitrophenol in aqueous medium. The fabricated sensor exhibited extremely high sensitivity of ~ 1285.76 µA/mmol L(-1)cm(-2) and an experimental detection limit of 0.078 mmol L(-1) with a linear dynamic range of 0.078-1.25 mmol L(-1). The obtained results confirmed that the prepared porous ZnO-SnO2 nanosheets are potential material for the removal of organic pollutants under visible light irradiation and efficient chemical sensing applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. POWERFUL ACTIVITY IN THE BRIGHT AGES. I. A VISIBLE/IR SURVEY OF HIGH REDSHIFT 3C RADIO GALAXIES AND QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Hilbert, B.; Chiaberge, M.; Kotyla, J. P.; Sparks, W. B.; Macchetto, F. D. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Tremblay, G. R. [Yale University, Department of Astronomy, 260 Whitney Avenue, New Haven, CT 06511 (United States); Stanghellini, C. [INAF—Istituto di Radioastronomia, Via P. Gobetti, 101 I-40129 Bologna (Italy); Baum, S.; O’Dea, C. P. [University of Manitoba, Dept of Physics and Astronomy, 66 Chancellors Circle, Winnipeg, MB R3T 2N2 (Canada); Capetti, A. [Osservatorio Astronomico de Torino, Corso Savona, I-10024 Moncalieri TO (Italy); Miley, G. K. [Universiteit Leiden, Rapenburg 70, 2311 EZ Leiden (Netherlands); Perlman, E. S. [Florida Institute of Technology, 150 W University Boulevard, Melbourne, FL 32901 (United States); Quillen, A. [Rochester Institute of Technology, School of Physics and Astronomy, 84 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2016-07-01

    We present new rest-frame UV and visible observations of 22 high- z (1 < z < 2.5) 3C radio galaxies and QSOs obtained with the Hubble Space Telescope ’s Wide Field Camera 3 instrument. Using a custom data reduction strategy in order to assure the removal of cosmic rays, persistence signal, and other data artifacts, we have produced high-quality science-ready images of the targets and their local environments. We observe targets with regions of UV emission suggestive of active star formation. In addition, several targets exhibit highly distorted host galaxy morphologies in the rest frame visible images. Photometric analyses reveal that brighter QSOs generally tend to be redder than their dimmer counterparts. Using emission line fluxes from the literature, we estimate that emission line contamination is relatively small in the rest frame UV images for the QSOs. Using archival VLA data, we have also created radio map overlays for each of our targets, allowing for analysis of the optical and radio axes alignment.

  11. Highly transparent conductive AZO/Zr50Cu50/AZO films in wide range of visible and near infrared wavelength grown by pulsed laser deposition

    Directory of Open Access Journals (Sweden)

    Jingyun Cheng

    Full Text Available Novel AZO/Zr50Cu50/AZO tri-layer transparent conductive films with excellent transmittance in both visible and near infrared region were successfully prepared by pulsed laser deposition on glass substrates. The electrical and optical properties were investigated at various Zr50Cu50 thicknesses. As the AZO thickness was fixed at 50 nm and Zr50Cu50 thickness was varied between 1 and 18 nm, it was found that AZO (50 nm/Zr50Cu50/AZO (50 nm tri-layer films exhibited good conductivity and high transmittance in both visible and near infrared wavelength. Additionally, both the electrical and optical properties of AZO (50 nm/Zr50Cu50 (2 nm/AZO (50 nm tri-layer films were found to be sensitive to the growth temperature. In this work, the lowest sheet resistance (43 Ω/□ and relatively high transmittance (∼80% in the range of 400–2000 nm were achieved while the growth temperature was 350 °C. Furthermore, the AZO (50 nm/Zr50Cu50 (2 nm/AZO (50 nm thin film deposited at 350 °C exhibits the highest figure of merit of 1.42 × 10−3 Ω−1, indicating that the multilayer is promising for coated glasses and thin film solar cells. Keywords: Transparent conductive oxide, AZO, Zr50Cu50, Electrical and optical properties, Visible and near infrared transmittance

  12. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    Obesity and overweight are lifestyle conditions affecting more than half of the ... bined with high-calorie intake, smoking, alcohol intake ..... healthy lifestyle to prevent future risk of obesity. .... also explains why there was high prevalence of obe-.

  13. Research Article

    African Journals Online (AJOL)

    2016-06-18

    Jun 18, 2016 ... renewable energies and in this extend, application of renewable ... The strategy to develop the space construction in high stature as the population product and ..... have the high rate among the intelligent buildings, figure 12.

  14. Original Article

    OpenAIRE

    鈴木, 幸子

    1998-01-01

    The purpose of this research was to clarify factors which affect adolescent women's health behavior concerning menstruation, and especially to clarify their mother's influence. The number of the participants were: 7 junior high school students and their mothers, 10 high school students and their mothers, 7 high school students and their mothers and 1 junior high school student and her mother who consulted a physician of adolescence clinic on menstrual pain. Questionnaire investigation about m...

  15. Visibility of an iron-containing fiducial marker in magnetic resonance imaging for high-precision external beam prostate radiotherapy.

    Science.gov (United States)

    Tanaka, Osamu; Komeda, Hisao; Hirose, Shigeki; Taniguchi, Takuya; Ono, Kousei; Matsuo, Masayuki

    2017-11-29

    Visualization of fiducial gold markers is critical for registration on computed tomography (CT) and magnetic resonance imaging (MRI) for imaging-guided radiotherapy. Although larger markers provide better visualization on MRI, they tend to generate artifacts on CT. MRI is strongly influenced by the presence of metals, such as iron, in the body. Here we compared efficacies of a 0.5% iron-containing gold marker (GM) and a traditional non-iron-containing marker. Twenty-seven patients underwent CT/MRI fusion-based intensity-modulated radiotherapy. Markers were placed by urologists under local anesthesia. Gold Anchor (GA; diameter: 0.28 mm; length: 10 mm), an iron-containing marker, was placed on the right side of the prostate using a 22-G needle and VISICOIL (VIS; diameter: 0.35 mm; length: 10 mm), a non-iron-containing marker, was placed on the left side using a 19-G needle. T2*-weighted images MRI sequences were obtained. Two radiation oncologists and a radiation technologist evaluated and assigned scores for visual quality on a five-point scale (1, poor; 5, best visibility). Artifact generation on CT was slightly greater with GA than with VIS. The mean marker visualization scores on MRI of all three observers were significantly superior for GA than for VIS (3.5 vs 3.2, 3.9 vs 3.2, and 4.0 vs 2.9). The actual size of the spherical GA was about 2 mm in diameter, but the signal void on MRI was approximately 5 mm. Although both markers were well visualized and can be recommended clinically, the results suggest that GA has some subtle advantages for quantitative visualization that could prove useful in certain situations of stereotactic body radiotherapy and intensity-modulated radiotherapy. © 2017 John Wiley & Sons Australia, Ltd.

  16. Synthesis of nitrogen-doped graphene–ZnS quantum dots composites with highly efficient visible light photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shu-Dong; Tang, Gang [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Ma, Yi-Fei [CAS Key Laboratory of Crust-Mantle Materials and Environments, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026 (China); Hu, Yuan, E-mail: yuanhu@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Suzhou Key Laboratory of Urban Public Safety, Suzhou Institute for Advanced Study, University of Science and Technology of China, 166 Ren' ai Road, Suzhou, Jiangsu 215123 (China); Song, Lei [State Key Laboratory of Fire Science, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China)

    2015-02-01

    Nitrogen-doped graphene–ZnS quantum dots (NG–ZnS QDs) were synthesized by a one-pot hydrothermal process using graphene oxide and [(Zn{sub 2}S{sub 2}) (pa)] nanosheets as precursors. The results demonstrated that ZnS QDs deposited on the surface of the nitrogen-doped graphene (NG). Combined with series of our analysis and characterization, we found that [(Zn{sub 2}S{sub 2}) (pa)] nanosheets were used not only as the sources of ZnS QDs but also as the sources of nitrogen. Moreover, photocatalytic experiment of NG–ZnS QDs for organic dyes was conducted under visible light irradiation, and the results exhibited that the photocatalytic activities of resultant composites could be remarkably enhanced. This simple and catalyst-free approach for depositing ZnS QDs onto NG may provide an alternative way for preparation of other composites based on NG under mild conditions, which showed their potential applications in wastewater treatment. - Graphical abstract: Schematic of the four-step process of the photon-driven CT model for NG–ZnS QDs. - Highlights: • A new strategy was present to synthesize nitrogen-doped graphene–ZnS quantum dots (NG–ZnS QDs) composites. • [(Zn{sub 2}S{sub 2}) (pa)] nanosheets were used not only as the sources of ZnS QDs but also as the sources of nitrogen. • The photocatalytic activities of NG–ZnS QDs could be remarkably enhanced.

  17. 450-nm GaN laser diode enables high-speed visible light communication with 9-Gbps QAM-OFDM.

    Science.gov (United States)

    Chi, Yu-Chieh; Hsieh, Dan-Hua; Tsai, Cheng-Ting; Chen, Hsiang-Yu; Kuo, Hao-Chung; Lin, Gong-Ru

    2015-05-18

    A TO-38-can packaged Gallium nitride (GaN) blue laser diode (LD) based free-space visible light communication (VLC) with 64-quadrature amplitude modulation (QAM) and 32-subcarrier orthogonal frequency division multiplexing (OFDM) transmission at 9 Gbps is preliminarily demonstrated over a 5-m free-space link. The 3-dB analog modulation bandwidth of the TO-38-can packaged GaN blue LD biased at 65 mA and controlled at 25°C is only 900 MHz, which can be extended to 1.5 GHz for OFDM encoding after throughput intensity optimization. When delivering the 4-Gbps 16-QAM OFDM data within 1-GHz bandwidth, the error vector magnitude (EVM), signal-to-noise ratio (SNR) and bit-error-rate (BER) of the received data are observed as 8.4%, 22.4 dB and 3.5 × 10(-8), respectively. By increasing the encoded bandwidth to 1.5 GHz, the TO-38-can packaged GaN blue LD enlarges its transmission capacity to 6 Gbps but degrades its transmitted BER to 1.7 × 10(-3). The same transmission capacity of 6 Gbps can also be achieved with a BER of 1 × 10(-6) by encoding 64-QAM OFDM data within 1-GHz bandwidth. Using the 1.5-GHz full bandwidth of the TO-38-can packaged GaN blue LD provides the 64-QAM OFDM transmission up to 9 Gbps, which successfully delivers data with an EVM of 5.1%, an SNR of 22 dB and a BER of 3.6 × 10(-3) passed the forward error correction (FEC) criterion.

  18. Low-Temperature Sol-Gel Synthesis of Nitrogen-Doped Anatase/Brookite Biphasic Nanoparticles with High Surface Area and Visible-Light Performance

    Directory of Open Access Journals (Sweden)

    Liang Jiang

    2017-12-01

    Full Text Available Nitrogen doping in combination with the brookite phase or a mixture of TiO2 polymorphs nanomaterials can enhance photocatalytic activity under visible light. Generally, nitrogen-dopedanatase/brookite mixed phases TiO2 nanoparticles obtained by hydrothermal or solvothermal method need to be at high temperature and with long time heating treatment. Furthermore, the surface areas of them are low (<125 m2/g. There is hardly a report on the simple and direct preparation of N-doped anatase/brookite mixed phase TiO2 nanostructures using sol-gel method at low heating temperature. In this paper, the nitrogen-doped anatase/brookite biphasic nanoparticles with large surface area (240 m2/g were successfully prepared using sol-gel method at low temperature (165 °C, and with short heating time (4 h under autogenous pressure. The obtained sample without subsequent annealing at elevated temperatures showed enhanced photocatalytic efficiency for the degradation of methyl orange (MO with 4.2-, 9.6-, and 7.5-fold visible light activities compared to P25 and the amorphous samples heated in muffle furnace with air or in tube furnace with a flow of nitrogen at 165 °C, respectively. This result was attributed to the synergistic effects of nitrogen doping, mixed crystalline phases, and high surface area.

  19. Novel development of nanocrystalline kesterite Cu2ZnSnS4 thin film with high photocatalytic activity under visible light illumination

    Science.gov (United States)

    Apostolopoulou, Andigoni; Mahajan, Sandip; Sharma, Ramphal; Stathatos, Elias

    2018-01-01

    Cu2ZnSnS4 (CZTS) represents a promising p-type direct band gap semiconductor with large absorption coefficient in the visible region of solar light. In the present study, a kesterite CZTS nanocrystalline film, with high purity, was successfully synthesized via the combination of successive ionic layer adsorption and reaction (SILAR) and chemical bath deposition (CBD) technique. The morphology and structural properties of the CZTS films were characterized by FE-SEM microscopy, porosimetry in terms of Brunauer-Emmett-Teller (BET) technique, X-ray diffraction and Raman spectroscopy. The as-prepared films under mild heat treatment at 250 °C in the presence of sulfur atmosphere exhibited fine nanostructure with 35 nm average particle size, high specific surface area of 53 m2/g and 9 nm pore diameter. The photocatalytic activity of the films was examined to the degradation of Basic Blue 41 (BB-41) and Acid Orange 8 (AO-8) organic azo dyes under visible light irradiation, demonstrating 97.5% and 70% discoloration for BB-41 and AO-8 respectively. Reusability of the CZTS films was also tested proving good stability over several repetitions. The reduction of photocatalyst's efficiency after three successive repetitions didn't exceed 5.6% and 8.5% for BB-41 and AO-8 respectively.

  20. Communications article

    KAUST Repository

    Fariborzi, Hossein

    2017-07-20

    Seamless, covert communications using a communications system integrated or incorporated within an article of clothing is described. In one embodiment, the communications system is integrated or incorporated into a shoe insole and includes a haptic feedback mechanism, a communications module, a flexible pressure sensor, and a battery. The communications module includes a wireless communications module for wireless communications, a wired interface for wired communications, a microcontroller, and a battery charge controller. The flexible pressure sensor can be actuated by an individual\\'s toe, for example, and communication between two communications nodes can be achieved using coded signals sent by individuals using a combination of long and short presses on the pressure sensor. In response to the presses, wireless communications modules can transmit and receive coded signals based on the presses.

  1. Article choice, theory of mind, and memory in children with high-functioning autism and children with specific language impairment

    NARCIS (Netherlands)

    Schaeffer, J.; van Witteloostuijn, M.; Creemers, A.

    2017-01-01

    Previous studies show that young, typically developing (TD) children (age 5) make errors in the choice between a definite and an indefinite article. Suggested explanations for overgeneration of the definite article include failure to

  2. Copper NPs decorated titania: A novel synthesis by high energy US with a study of the photocatalytic activity under visible light.

    Science.gov (United States)

    Stucchi, Marta; Bianchi, Claudia L; Pirola, Carlo; Cerrato, Giuseppina; Morandi, Sara; Argirusis, Christos; Sourkouni, Georgia; Naldoni, Alberto; Capucci, Valentino

    2016-07-01

    The most important drawback of the use of TiO2 as photocatalyst is its lack of activity under visible light. To overcome this problem, the surface modification of commercial micro-sized TiO2 by means of high-energy ultrasound (US), employing CuCl2 as precursor molecule to obtain both metallic copper as well as copper oxides species at the TiO2 surface, is here. We have prepared samples with different copper content, in order to evaluate its impact on the photocatalytic performances of the semiconductor, and studied in particular the photodegradation in the gas phase of some volatile organic molecules (VOCs), namely acetone and acetaldehyde. We used a LED lamp in order to have only the contribution of the visible wavelengths to the TiO2 activation (typical LED lights have no emission in the UV region). We employed several techniques (i.e., HR-TEM, XRD, FT-IR and UV-Vis) in order to characterize the prepared samples, thus evidencing different sample morphologies as a function of the various copper content, with a coherent correlation between them and the photocatalytic results. Firstly, we demonstrated the possibility to use US to modify the TiO2, even when it is commercial and micro-sized as well; secondly, by avoiding completely the UV irradiation, we confirmed that pure TiO2 is not activated by visible light. On the other hand, we showed that copper metal and metal oxides nanoparticles strongly and positively affect its photocatalytic activity. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Synthesis of S/Cr doped mesoporous TiO2 with high-active visible light degradation property via solid state reaction route

    International Nuclear Information System (INIS)

    Liu Shaoyou; Tang Qunli; Feng Qingge

    2011-01-01

    S/Cr doped mesoporous TiO 2 (S-TiO 2 , Cr-TiO 2 , S-Cr-TiO 2 ) were successfully synthesized via a simple, effective and environmental benign solid state reaction route. The low angle XRD patterns demonstrated that the resulting samples possess mesostructures. The further characterizations via N 2 adsorption-desorption and XPS showed that the typical S/Cr co-doped mesoporous TiO 2 (S-Cr-TiO 2 (5S-5Cr)) possesses mesopore with the high specific surface area of 118.4 m 2 /g and narrow pore size distribution, and both S and Cr have been incorporated into the lattice of TiO 2 with the amounts of 4.16% sulfur and 7.88% chromium, respectively. And Raman spectroscopy shows that the surface of S-Cr-TiO 2 (5S-5Cr) material possesses stretching vibrational peaks at ∼709, ∼793 cm -1 are assignable to the Ti-O-Cr, O-Cr (Ti)-OH bonds, respectively. Interestingly, the UV-vis displayed that the absorption regions of S/Cr doped mesoporous TiO 2 cover the visible light region. As for the series of S-Cr-TiO 2 samples, the absorption region even extends to near infrared region with strong adsorption. Moreover, compared with the pure titanium dioxide (P25-TiO 2 ), the photodegradation properties of bromocresol green (BCG) on the S/Cr doped mesoporous TiO 2 showed excellent photocatalytic properties under visible light irradiation. Within 50 min visible light irradiation, 82.6% of the initial BCG was degraded for the S-Cr-TiO 2 (6S-4Cr) photocatalyst.

  4. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    User

    derson J.W., Elam M.B., Faas F.H., Linares. E., Schaefer E.J., Schectman G., Wilt T.J. and Wittes J. (1999) Gemfibrozil for the secondary prevention of coronary heart disease in men with low levels of high- density lipoprotein cholesterol. Veterans. Affairs High-Density Lipoprotein Choles- terol Intervention Trial Study Group.

  5. Visibility and Haze

    Science.gov (United States)

    Haze forms when sunlight encounters particle pollution. It reduces visibility in cities and scenic areas. This web area provides regulatory information and progress towards improving visibility through EPA’s regional haze program.

  6. Visible Human Project

    Science.gov (United States)

    ... cryosections are associated with anatomical terminology. AnatLine : A prototype system consisting of an anatomical image database and ... further information is available Publications VHJOE: Visible Human Journal of Endoscopy. NLM's Current Bibliographies in Medicine, Visible ...

  7. Visibly Pushdown Automata

    DEFF Research Database (Denmark)

    Srba, Jiri

    2006-01-01

    We investigate the possibility of (bi)simulation-like preorder/equivalence checking on the class of visibly pushdown automata and its natural subclasses visibly BPA (Basic Process Algebra) and visibly one-counter automata. We describe generic methods for proving complexity upper and lower bounds...... for a number of studied preorders and equivalences like simulation, completed simulation, ready simulation, 2-nested simulation preorders/equivalences and bisimulation equivalence. Our main results are that all the mentioned equivalences and preorders are EXPTIME-complete on visibly pushdown automata, PSPACE......-complete on visibly one-counter automata and P-complete on visibly BPA. Our PSPACE lower bound for visibly one-counter automata improves also the previously known DP-hardness results for ordinary one-counter automata and one-counter nets. Finally, we study regularity checking problems for visibly pushdown automata...

  8. ORIGINAL .ARTICLES

    African Journals Online (AJOL)

    poor countries. J M Wilmshurst, Ronald van Toorn, C R J C Newton. Parenteral phenobarbitone is. an integral part of the management of status epilepticus, especially in the context of resource-poor countries. It is highly effective at controlling.

  9. ~ ORIGINAL ARTICLES

    African Journals Online (AJOL)

    Professor eil White performed occupational assessments on several of the patients. ... study assessed whether early 'high-dose' IS therapy in new patients with generalised MG ...... cancer in patients receiving azathioprine."' The experience of.

  10. Research Article

    African Journals Online (AJOL)

    2018-05-01

    May 1, 2018 ... High Utility Mining, Constraint Mining. ..... which can help the retailer to know the need of customers and as a future action stores layout may change .... Conference on Communication Systems and Network Technologies (pp.

  11. Research Article

    African Journals Online (AJOL)

    regenerate vulnerable environments due to their high social correlations. ... Climate changes, earthquakes, and emergencies caused by human-made structures .... and persistence, gender, age, nationality, family type, financial situation and children, ... paid job opportunities, school access, and better sanitary services.

  12. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    sex, transactional sex and non-consensual sex put adolescent girls at high ... Medical Research Institute, Nelson R Mandela School of Medicine, University of ... the safety, immunogenicity and efficacy of the vaccine in .... About one-third of the.

  13. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    management of hypercholesterolaemia in patients attending general practitioners in ... exceptionally high (77.5% of women and 64.4% of men). The most commonly ... company updates this list at regular intervals and identifies the number of ...

  14. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    User

    Cardiovascular disease is one of the major chronic diseases ... countries, the prevalence of cardiovascular diseases ..... thirty Nigerian patients in Lagos. ... Treatment of High Blood Cholesterol in ... Dental and Medical Sciences 9 (3):07 – 12.

  15. ORIGINAL ARTICLES

    African Journals Online (AJOL)

    most common presenting complaint being vaginal bleeding. Three of the 5 ... the uterine cervix are rare, unusual and highly aggressive tumours with Jess than SO .... and Messrs Mike. Lanesman and Guy Hall for the photomicrography, and Mr.

  16. Research Article

    African Journals Online (AJOL)

    2016-06-10

    Jun 10, 2016 ... and chloroform extract was the lowest antioxidant activity (aerial parts, ... of this genus represents anti diabetic, diuretic, high blood pressure, ..... P., Ferreres, F. In vitro studies to assess the antidiabetic, anti-cholinesterase and.

  17. ORIGINAL ARTICLES

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    monoclonal amphetamine-assay result of antipsychotic drug therapy. Clin Chern 1993; 39: .... reported by the family at accessible clinic or mobile points. A history and .... service delivery; (ii) disability prevention must be a high priority because ...

  18. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    dell

    The progress of science and technology is the major areas where society comes up for essential ... Hence teaching Mathematics at high school levels should ... Mathematics school teachers, and students at different grade levels were the.

  19. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    Data regarding the age, sex, clinical diagnosis, and treatment outcomes were all retrieved from the ... Prenatal screening and diagnosis are highly recommended since most women undergo routine ultrasonography as ..... stage breast cancer.

  20. Original Article

    African Journals Online (AJOL)

    with chronic HCV infection (n=45) and diabetic patients without HCV infection ... glycemic control, high blood pressure, proteinuria, lipid abnormalities ... postural hypotension. ... older with HCV infection were more than three times more likely ...

  1. Research Article

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... environmental pollution and reducing energy consumption, using wind turbines for wind ... Strategy of high rise buildings and spatial development in height as population growth and ..... rank among smart buildings (Fig, 12).

  2. Research Article

    African Journals Online (AJOL)

    2016-06-18

    Jun 18, 2016 ... High-pressure technologies create processes that produce new products ... modeling and simulation of thermodynamic systems. .... Phase equilibrium calculations has been conducted based on the Eq. (2) and using MATLAB.

  3. Facile synthesis of flower-like BiOI hierarchical spheres at room temperature with high visible-light photocatalytic activity

    International Nuclear Information System (INIS)

    Wang, Xiao-jing; Li, Fa-tang; Li, Dong-yan; Liu, Rui-hong; Liu, Shuang-jun

    2015-01-01

    Graphical abstract: - Highlights: • Flower-like BiOI hierarchical sphere is obtained in the presence of ethylene glycol. • A template free hydrolysis route is employed at room temperature. • Ethylene glycol plays an important role in assembling BiOI nanoflakes to form spheres. • The BiOI sphere shows high visible-light photocatalytic activity and good stability. - Abstract: Flower-like BiOI hierarchical spheres are prepared at room temperature via a template free route simply by dropping water into ethylene glycol (EG) solution containing reactants based on the hydrolysis and oriented assembly roles of water and EG, respectively. The BiOI samples are characterized by X-ray diffraction (XRD), nitrogen adsorption/desorption, emission scanning electron microscopy (SEM), UV–Vis diffuse reflectance spectra (UV–Vis DRS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The photocatalytic reaction rate constant of the as-prepared BiOI hierarchical spheres is 15.8, 13.3, and 2.0 times that of BiOI nanoflakes obtained in the absence of EG in degradation of anionic dye (methyl orange), cationic dye (methylene blue), and colorless target pollutant (phenol), respectively, under the visible-light irradiation, which can be attributed to its unique flower-like structure for utilization of light, small crystal size, and large specific surface area

  4. Vacancy-Rich Monolayer BiO2-x as a Highly Efficient UV, Visible, and Near-Infrared Responsive Photocatalyst.

    Science.gov (United States)

    Li, Jun; Wu, Xiaoyong; Pan, Wenfeng; Zhang, Gaoke; Chen, Hong

    2018-01-08

    Vacancy-rich layered materials with good electron-transfer property are of great interest. Herein, a full-spectrum responsive vacancy-rich monolayer BiO 2-x has been synthesized. The increased density of states at the conduction band (CB) minimum in the monolayer BiO 2-x is responsible for the enhanced photon response and photo-absorption, which were confirmed by UV/Vis-NIR diffuse reflectance spectra (DRS) and photocurrent measurements. Compared to bulk BiO 2-x , monolayer BiO 2-x has exhibited enhanced photocatalytic performance for rhodamine B and phenol removal under UV, visible, and near-infrared light (NIR) irradiation, which can be attributed to the vacancy V Bi-O ''' as confirmed by the positron annihilation spectra. The presence of V Bi-O ''' defects in monolayer BiO 2-x promoted the separation of electrons and holes. This finding provides an atomic level understanding for developing highly efficient UV, visible, and NIR light responsive photocatalysts. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. High photocatalytic activity of hierarchical SiO2@C-doped TiO2 hollow spheres in UV and visible light towards degradation of rhodamine B.

    Science.gov (United States)

    Zhang, Ying; Chen, Juanrong; Hua, Li; Li, Songjun; Zhang, Xuanxuan; Sheng, Weichen; Cao, Shunsheng

    2017-10-15

    Ongoing research activities are targeted to explore high photocatalytic activity of TiO 2 -based photocatalysts for the degradation of environmental contaminants under UV and visible light irradiation. In this work, we devise a facile, cost-effective technique to in situ synthesize hierarchical SiO 2 @C-doped TiO 2 (SCT) hollow spheres for the first time. This strategy mainly contains the preparation of monodisperse cationic polystyrene spheres (CPS), sequential deposition of inner SiO 2 , the preparation of the sandwich-like CPS@SiO 2 @CPS particles, and formation of outer TiO 2 . After the one-step removal of CPS templates by calcination at 450°C, hierarchical SiO 2 @C-doped TiO 2 hollow spheres are in situ prepared. The morphology, hierarchical structure, and properties of SCT photocatalyst were characterized by TEM. SEM, STEM Mapping, BET, XRD, UV-vis spectroscopy, and XPS. Results strongly confirm the carbon doping in the outer TiO 2 lattice of SCT hollow spheres. When the as-synthesized SCT hollow spheres were employed as a photocatalyst for the degradation of Rhodamine B under visible-light and ultraviolet irradiation, the SCT photocatalyst exhibits a higher photocatalytic activity than commercial P25, effectively overcoming the limitations of poorer UV activity for many previous reported TiO 2 -based photocatalysts due to doping. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. ORIGINAL ARTICLE

    African Journals Online (AJOL)

    2011-04-01

    Apr 1, 2011 ... The absence of this peak in the Western Cape corresponds with a delayed provincial HIV epidemic, and exceptionally high coverage of pregnant women with PMTCT interventions of increasing effectiveness. PMTCT was first introduced in the Western Cape in. 1999 in Khayelitsha,14 following the protocols ...

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    those who revere technology and regard it as the major factor ... easier to think of technology as being human artefacts, such as machines ... We can touch it, see it, buy it, possess it, brag ... modern technology, as in the fashion industry we add the word. 'high'. ..... investment and the pressures to over-service are indeed very.

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    Implementation of an online scheduling support system in a high mix manufacturing firm. Author(s): L. Siva Rama Krishna1*, V. Mahesh2, Sandeep Dulluri 3, C. S. P. Rao4 ... A priority based heuristic for minimizing the makespan is presented.

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    May 1, 2017 ... of the final polymer and the conversion has been studied. Keywords: dental ... Available online at http://www.jfas. ... process and the high rate of this reaction As well as the exothermic effect resulting from the reaction may be ...

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    energy consumption and expenditure (Bouchard et al., 2003; Fezeu et ..... study, for instance, reflected the very high levels in ... relation with an increased risk of ill health than BMI alone. This point is further echoed by the WHO statement that BMI can be used to estimate the .... obesity among Ghanaian adults; Public Health.

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    May 1, 2018 ... Keywords: risk analysis; risk management; petroleum products; roads; pipelines. ... has for several years made a major impact on global, national, and local economies. Hussain [2] identified that highly inflexible logistics network is one of ... supply chain begins with the exploration and production of crude ...

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    Feb 24, 2018 ... In this century, high efficiency and safety in the design and operation of the ... This system had 6 generator buses and 25 load buses with 41 ..... Optimal Spinning Reserve for a Wind-Thermal Power System Using EIPSO.

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    Jun 18, 2016 ... nd simulated in system level using MATLAB/SIMULINK. ... shorter design cycle, embedded processor usage capability and high hardware density ... Angular measurement of the rotor position is an essential parameter in PMSM control ... There are two types of encoders that are used in these applications:.

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    Improved resistance to fatigue. 15. 37.5 .... in the prevalence of. AAS use are interesting and prOVide a useful model for trying ... Athletes' projections of anabolic steroid use. elm Sports ... of Mathematical Statistics, L'niver5ity of Cape Town, 1991. 23. ... Test-retest reliability and validity information for a high .school drug use.

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    The mean low density lipoprotein (LDLc) was observed to be significantly .... composed of 52 females and 38 males (sex ratio. 1.37:1). ... dL; TC= total cholesterol, mg/dL; TG=triglyceride, mg/dL; HDL=high density lipoprotein, mg/dL;. LDL=low ...

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    May 1, 2018 ... and in the poor ranking was 24%, the mean age of the participants ... Women's knowledge was 53.1% higher than that of men with a ... of high blood pressure in Iran is reported to be 12.5 percent lower than .... sections of the hospital, include 70 administrative departments and ..... it is known to other media.

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    Jan 1, 2017 ... ... recent developments in the fields of adsorption, catalysis, luminescence, ... particularly syntheses of molecules with unusual electronic ... are strong donors, and therefore, they were found to efficiently stabilize high oxidation states ...... New developments in the field of vitamin B12: Reactions of the cobalt.

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    Objectives. To determine the diagnostic yield of computed tomography (CT) of the head in children presenting for the first time with partial seizures in a region with a high prevalence of tuberculosis and neurocysticercosis. Design. Prospective cohort study. Setting. The secondary-level ambulatory service of Red Cross.

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    AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY MAY 2017 ... The reserve has had a history of high prevalence of the disease and farmers in the area are known to ignore the control of trypanosomiasis in sheep and goats and focus more on cattle. .... Previous reports in Northern Nigeria range.

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    Sep 9, 2001 ... primary diabetes care in Cape Town, South Africa: high prevalence of complications, uncontrolled hyperglycaemia, and hypertension. DiDbet Med 1997; 14: 1073-1077. 12. World Health Organisation Expert Committee. Arterial Hypertension. Report of a WHO. Expert Committee. World Health Organ Teclz ...

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    information is available and a confident assessment of poor prognosis can be made. .... from informal, poorly controlled games rather than from school sport. The South African Rugby Board has put enormous effort into education, and .... Quality of life and self-esteem were reported to be high, and. 95% reported being 'glad ...

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    The agressive management of generalised MG (classes Il-V) consisted of restoration of normal strength using high-dose daily or alternate-day corticosteroids orally or parenterally, equivalent to 50 -100 mg prednisone,11 and early thymectomy. (within a year of diagnosis).12. Long-term follow-up until true remission (cure) ...

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    incidence rates being as high as 8% in the United States. (Delzell and Lefevre ... Other studies have also reported .... (1994) in a study on bacteriuria in pregnancy reported that the .... imity of the anal and urogenital opening in females makes it ...

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    maintenance of a high routine immunisation coverage (at least. 90% of children under 1 year), .... Concerned parents who keep a road-to-health card will be more likely to have .... The winter 1996 mass immunisation campaign- is it the best ...

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    High School near Elim, a position he held until his death in. 1949. He was an .... and many representations from local people, farmers, businessmen and politicians ... With the source of doctors from Europe drying up, new recruits from Eastern ...

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    Jun 9, 2016 ... The process of estimation occurs in two stages: in the first stage, the high orders of the signal are estimated ..... In this section we describe the simulation using the theory in the previous section on. MATLAB software. .... [20]Zhou G and Giannakis G. B. On estimating random amplitude modulated harmonics.

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    the highly vascular nature of the tumours (Fig, 2, c), but did not stain sinusoids .... patients with chronic liver disease_ N Engl JMed 1993; 328, 797-801. 9. Shiina 5, Yasua ... Couinaud C. u Foie: Etudes Anatomiques

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    2017-01-01

    Jan 1, 2017 ... Keywords: ConXL moment connection; collar; concrete filled steel tube (CFT); ... Design of beam-column connections is important in steel structures with tube columns. ... Moreover, high lateral-torsional stiffness and inconsiderable ... Then, these forces pass through the rear collars bolts on the opposite.

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    May 15, 2016 ... interior spaces that will help educational optimization significantly. Perhaps some believe that ... than half after proper implementation of thermal insulation. .... Applying simple and understandable volumes for child and avoidance of any complexity in ... High safety because of low weight. * Reduction of ...

  10. Visible-Light-Initiated Na2-Eosin Y Catalyzed Highly Regio- and Stereoselective Difunctionalization of Alkynes with Alkyl Bromides.

    Science.gov (United States)

    Wang, Kuai; Meng, Ling-Guo; Wang, Lei

    2016-08-19

    A highly regioselective and stereoselective addition of alkyl bromides (amino-brominated aromatic β,β-dicyanoalkenes) to arylacetylenes by photoredox catalysis was developed. This difunctionalization of arylacetylenes was accomplished under ambient and metal-free conditions to produce alkenyl bromides in high efficiency with a wide range of group tolerance.

  11. Original Article

    African Journals Online (AJOL)

    and >5000 mg/kg (oral, slightly toxic) and the LD50 of the JC extract for the chicks was 28.28 mg/kg (IP, highly toxic). .... gender and age (i.e. adult male rats, adult female rats and ..... The rats were treated with single doses IP amphetamine (left) or chlorpromazine. (right) and EEG-EMG recordings were done 24 hour later. 0.

  12. Facile synthesis of AgI/BiOI-Bi{sub 2}O{sub 3} multi-heterojunctions with high visible light activity for Cr(VI) reduction

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qi [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Shi, Xiaodong; Liu, Enqin [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Crittenden, John C. [The Brook Byer Institute for Sustainable Systems and School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta 30332 (United States); Ma, Xiangjuan; Zhang, Yi [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China); Cong, Yanqing, E-mail: yqcong@hotmail.com [School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310018 (China)

    2016-11-05

    Graphical abstract: Highly visible-light-active AgI/BiOI-Bi{sub 2}O{sub 3} with multi-heterojunctions was developed. - Highlights: • Visible-light-active AgI/BiOI-Bi{sub 2}O{sub 3} with multi-heterojunctions was prepared. • Highly enhanced photocatalytic reduction of Cr(VI) was observed. • k{sub Cr(VI)} on AgI/BiOI-Bi{sub 2}O{sub 3} increased by ca.16 times relative to Bi{sub 2}O{sub 3}. • Decreased E{sub g}, shifted E{sub fb} and reduced charge transfer resistance were observed. • Simultaneous reduction of Cr(VI) and degradation of organics were achieved. - Abstract: AgI sensitized BiOI-Bi{sub 2}O{sub 3} composite (AgI/BiOI-Bi{sub 2}O{sub 3}) with multi-heterojunctions was prepared using simple etching-deposition process. Different characterization techniques were performed to investigate the structural, optical and electrical properties of the as-prepared photocatalysts. It was found that the ternary AgI/BiOI-Bi{sub 2}O{sub 3} composite exhibited: (1) improved photocurrent response, (2) smaller band gap, (3) greatly reduced charge transfer resistance and (4) negative shift of flat band potential, which finally led to easier generation and more efficient separation of photo-generated electron-hole pairs at the hetero-interfaces. Thus, for the reduction of Cr(VI), AgI/BiOI-Bi{sub 2}O{sub 3} exhibited excellent photocatalytic activity under visible light irradiation at near neutral pH. AgI/BiOI-Bi{sub 2}O{sub 3} was optimized when the initial molar ratio of KI to Bi{sub 2}O{sub 3} and AgNO{sub 3} to Bi{sub 2}O{sub 3} was 1:1 and 10%, respectively. The estimated k{sub Cr(VI)} on optimized AgI/BiOI-Bi{sub 2}O{sub 3} was about 16 times that on pure Bi{sub 2}O{sub 3}. Good stability was also observed in cyclic runs, indicating that the current multi-heterostructured photocatalyst is highly desirable for the remediation of Cr(VI)-containing wastewater.

  13. Solvent-assisted self-assembly of fullerene into single-crystal ultrathin microribbons as highly sensitive UV-visible photodetectors.

    Science.gov (United States)

    Wei, Lang; Yao, Jiannian; Fu, Hongbing

    2013-09-24

    The size, shape, and crystallinity of organic nanostructures play an important role in their physical properties and are mainly determined by the self-assembling kinetics of molecular components often involving the solvent conditions. Here, we reported a kinetically controlled self-assembly of C60 assisted by the solvent carbon bisulfide (CS2) into single-crystal ultrathin microribbons of 2C60·3CS2, upon mixing the poor solvent isopropyl alcohol with a C60/CS2 stock solution. Surface energy calculations reveal that these microribbons represent a kinetically favored high-energy state as compared with the thermodynamically stable shape of prismatic rods. High-resolution transmission electron microscopy observations clarify that association of CS2 at the nucleation stage helps to guide and rigidify the formation of π-π stacking 1D chains of C60 through the surrounding CS2 cage-like structures, which further act as glue, boosting lateral assembly of as-formed 1D chains into untrathin 2D microribbon single crystals. Precise control over the thickness, width, and length of 2C60·3CS2 microribbons was achieved by manipulation of the growth kinetics through adjusting the solvent conditions. Upon heating to 120 °C, sublimation of CS2 components results in fcc C60 microribbons. We found that both microribbons of solvated monoclinic 2C60·3CS2 and pure fcc C60 exhibit highly sensitive photoconductivity properties with a spectral response range covering UV to visible. The highest on/off ratio of two-terminal photodetectors based on single ribbons reaches around 250, while the responsitivity is about 75.3 A W(-1) in the UV region and 90.4 A W(-1) in the visible region.

  14. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao

    2016-05-25

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  15. High-throughput screening assay used in pharmacognosy: Selection, optimization and validation of methods of enzymatic inhibition by UV-visible spectrophotometry

    Directory of Open Access Journals (Sweden)

    Graciela Granados-Guzmán

    2014-02-01

    Full Text Available In research laboratories of both organic synthesis and extraction of natural products, every day a lot of products that can potentially introduce some biological activity are obtained. Therefore it is necessary to have in vitro assays, which provide reliable information for further evaluation in in vivo systems. From this point of view, in recent years has intensified the use of high-throughput screening assays. Such trials should be optimized and validated for accurate and precise results, i.e. reliable. The present review addresses the steps needed to develop and validate bioanalytical methods, emphasizing UV-Visible spectrophotometry as detection system. Particularly focuses on the selection of the method, the optimization to determine the best experimental conditions, validation, implementation of optimized and validated method to real samples, and finally maintenance and possible transfer it to a new laboratory.

  16. High-brightness semipolar (2021¯) blue InGaN/GaN superluminescent diodes for droop-free solid-state lighting and visible-light communications

    KAUST Repository

    Shen, Chao; Ng, Tien Khee; Leonard, John T.; Pourhashemi, Arash; Nakamura, Shuji; DenBaars, Steven P.; Speck, James S.; Alyamani, Ahmed Y.; El-desouki, Munir M.; Ooi, Boon S.

    2016-01-01

    A high-brightness, droop-free, and speckle-free InGaN/GaN quantum well blue superluminescent diode (SLD) was demonstrated on a semipolar (2021) GaN substrate. The 447-nm emitting SLD has a broad spectral linewidth of 6.3 nm at an optical power of 123 mW. A peak optical power of 256 mW was achieved at 700 mA CW injection current. By combining YAG:Ce phosphor, SLD-generated white light shows a color-rendering index (CRI) of 68.9 and a correlated color temperature (CCT) of 4340 K. The measured frequency response of the SLD revealed a -3 dB bandwidth of 560 MHz, thus demonstrating the feasibility of the device for both solid-state lighting (SSL) and visible-light communication (VLC) applications. © 2016 Optical Society of America.

  17. High-Quality Fe-doped TiO2 films with Superior Visible-Light Performance

    DEFF Research Database (Denmark)

    Su, Ren; Bechstein, Ralf; Kibsgaard, Jakob

    2012-01-01

    We report on high-quality polycrystalline Fe-doped TiO2 (Fe–TiO2) porous films synthesized via one-step electrochemical oxidation. We demonstrate that delicate properties such as the impurity concentration and the microstructure that strongly influence the performance of the material for photovol...

  18. Caracterização das publicações periódicas em fonoaudiologia e neurociências: estudo sobre os tipos e temas de artigos e visibilidade na área de linguagem Periodicals' profile in speech-language and hearing pathology and neurosciences: study on types and headers of the language area articles, and their visibility

    Directory of Open Access Journals (Sweden)

    Sandrelli Virginio de Vasconcelos

    2009-03-01

    Full Text Available TEMA: caracterização das publicações periódicas em Fonoaudiologia e Neurociências: estudo sobre os tipos e temas de artigos e visibilidade na área de linguagem. OBJETIVO: caracterizar as publicações periódicas em Fonoaudiologia estudando os artigos da área de Linguagem relacionados às Neurociências no período de 2002 a 2006. CONCLUSÃO: ficou evidente um aumento crescente de publicações em Linguagem e em Neurociências nos últimos cinco anos. Contudo, o número de publicações em determinados temas como a Dislexia, a Doença de Alzheimer e o Transtorno do Déficit de Atenção / Hiperatividade ainda mostra-se resumido.BACKGROUND: periodicals' profile in speechlanguage and hearing pathology and neurosciences: study on types and headers of the language articles, and their visibility. PURPOSE: to characterize periodicals in SpeechLanguage Pathology and Hearing, studying the articles of the Language's area related to Neurosciences in the period from 2002 to 2006. CONCLUSION: increasing publication in Language and Neurosciences in the last five years has been evident. However, number of publications in certain headers, such as dyslexia, Alzheimer's disease and AttentionDeficit/Hyperactivity Disorder are still abridged.

  19. Silica-forming articles having engineered surfaces to enhance resistance to creep sliding under high-temperature loading

    Science.gov (United States)

    Lipkin, Don Mark; Johnson, Curtis Alan; Meschter, Peter Joel; Sundaram, Sairam; Wan, Julin

    2017-02-07

    An article includes a silicon-containing region; at least one outer layer overlying a surface of the silicon-containing region; and a constituent layer on the surface of the silicon-containing region and between and contacting the silicon-containing region and the at least one outer layer, the constituent layer being formed by constituents of the silicon-containing region and being susceptible to creep within an operating environment of the article, wherein the silicon-containing region defines a plurality of channels and a plurality of ridges that interlock within the plurality of channels are formed in the silicon-containing region to physically interlock the at least one outer layer with the silicon-containing region through the constituent layer.

  20. Broadband and high absorption in Fibonacci photonic crystal including MoS2 monolayer in the visible range

    Science.gov (United States)

    Ansari, Narges; Mohebbi, Ensiyeh

    2018-03-01

    2D molybdenum disulfide MoS2, has represented potential applications in optoelectronic devices based on their promising optical absorption responses. However, for practical applications, absorption should increase furthermore in a wide wavelength window. In this paper, we design Fibonacci photonic crystals (PCs) based on Si, SiO2 and MoS2 monolayer and we calculate their absorption responses based on the transfer matrix method. The optical refractive index of the MoS2 monolayer was determined based on the Lorentz-Drude-Gauss model. Effects of Fibonacci order, periodicity, incident light angle and polarization are included in our calculations. Finally, an absorption as large as 90% in a wide optical wavelength range is achieved for both polarizations and incident angle down to 60°. Our results are useful for designing photonic devices with high absorption efficiency.

  1. Power mixture and green body for producing silicon nitride base articles of high fracture toughness and strength

    Science.gov (United States)

    Huckabee, M.L.; Buljan, S.T.; Neil, J.T.

    1991-09-17

    A powder mixture and a green body for producing a silicon nitride-based article of improved fracture toughness and strength are disclosed. The powder mixture includes (a) a bimodal silicon nitride powder blend consisting essentially of about 10-30% by weight of a first silicon nitride powder of an average particle size of about 0.2 [mu]m and a surface area of about 8-12m[sup 2]g, and about 70-90% by weight of a second silicon nitride powder of an average particle size of about 0.4-0.6 [mu]m and a surface area of about 2-4 m[sup 2]/g, (b) about 10-50 percent by volume, based on the volume of the densified article, of refractory whiskers or fibers having an aspect ratio of about 3-150 and having an equivalent diameter selected to produce in the densified article an equivalent diameter ratio of the whiskers or fibers to grains of silicon nitride of greater than 1.0, and (c) an effective amount of a suitable oxide densification aid. The green body is formed from the powder mixture, an effective amount of a suitable oxide densification aid, and an effective amount of a suitable organic binder. No Drawings

  2. Synthesis of TiO2 nanorod-decorated graphene sheets and their highly efficient photocatalytic activities under visible-light irradiation

    International Nuclear Information System (INIS)

    Lee, Eunwoo; Hong, Jin-Yong; Kang, Haeyoung; Jang, Jyongsik

    2012-01-01

    Highlights: ► TiO 2 nanorods were successfully decorated on the surface of graphene sheets. ► Population of TiO 2 nanorods can be controlled by changing experimental conditions. ► TiO 2 nanorod-decorated graphene sheets have an expanded light absorption range. ► TiO 2 nanorod-decorated graphene sheets showed unprecedented photocatalytic activity. - Abstract: The titanium dioxide (TiO 2 ) nanorod-decorated graphene sheets photocatalysts with different TiO 2 nanorods population have been synthesized by a simple non-hydrolytic sol–gel approach. Electron microscopy and X-ray diffraction analysis indicated that the TiO 2 nanorods are well-dispersed and successfully anchored on the graphene sheet surface through the formation of covalent bonds between Ti and C atoms. The photocatalytic activities are evaluated in terms of the efficiencies of photodecomposition and adsorption of methylene blue (MB) in aqueous solution under visible-light irradiation. The as-synthesized TiO 2 nanorod-decorated graphene sheets showed unprecedented photodecomposition efficiency compared to the pristine TiO 2 nanorods and the commercial TiO 2 (P-25, Degussa) under visible-light. It is believed that this predominant photocatalytic activity is due to the synergistic contribution of both a retarded charge recombination rate caused by a high electronic mobility of graphene and an increased surface area originated from nanometer-sized TiO 2 nanorods. Furthermore, photoelectrochemical study is performed to give deep insights into the primary roles of graphene that determines the photocatalytic activity.

  3. Modification of TiO{sub 2} nanorods by Bi{sub 2}MoO{sub 6} nanoparticles for high performance visible-light photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Li Na; Zhu Li [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Zhang Weide, E-mail: zhangwd@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Yu Yuxiang; Zhang Wenhui; Hou Meifang [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

    2011-10-13

    Highlights: > Bi{sub 2}MoO{sub 6}/TiO{sub 2} heterojunction photocatalysts. > Effective separation of photoexcited electrons and holes. > High visible light photocatalytic activity. - Abstract: In this work, TiO{sub 2} nanorods were prepared by a hydrothermal process and then Bi{sub 2}MoO{sub 6} nanoparticles were deposited onto the TiO{sub 2} nanorods by a solvothermal process. The nanostructured Bi{sub 2}MoO{sub 6}/TiO{sub 2} composites were extensively characterized by X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The photocatalytic activity of the Bi{sub 2}MoO{sub 6}/TiO{sub 2} composites was evaluated by degradation of methylene blue. The Bi{sub 2}MoO{sub 6}/TiO{sub 2} composites exhibit higher catalytic activity than pure Bi{sub 2}MoO{sub 6} and TiO{sub 2} for degradation of methylene blue under visible light irradiation ({lambda} > 420 nm). Further investigation revealed that the ratio of Bi{sub 2}MoO{sub 6} to TiO{sub 2} in the composites greatly influenced their photocatalytic activity. The experimental results indicated that the composite with Bi{sub 2}MoO{sub 6}:TiO{sub 2} = 1:3 exhibited the highest photocatalytic activity. The enhancement mechanism of the composite catalysts was also discussed.

  4. Real time high frequency monitoring of water quality in river streams using a UV-visible spectrometer: interest, limits and consequences for monitoring strategies

    Science.gov (United States)

    Faucheux, Mikaël; Fovet, Ophélie; Gruau, Gérard; Jaffrézic, Anne; Petitjean, Patrice; Gascuel-Odoux, Chantal; Ruiz, Laurent

    2013-04-01

    Stream water chemistry is highly variable in space and time, therefore high frequency water quality measurement methods are likely to lead to conceptual advances in the hydrological sciences. Sub-daily data on water quality improve the characterization of pollutant sources and pathways during flood events as well as during long-term periods [1]. However, real time, high frequency monitoring devices needs to be properly calibrated and validated in real streams. This study analyses data from in situ monitoring of a stream water quality. During two hydrological years (2010-11, 2011-12), a submersible UV-visible spectrometer (Scan Spectrolyser) was used for surface water quality measurement at the outlet of a headwater catchment located at Kervidy-Naizin, Western France (AgrHys long-term hydrological observatory, http://www.inra.fr/ore_agrhys/). The spectrometer is reagentless and equipped with an auto-cleaning system. It allows real time, in situ and high frequency (20 min) measurements and uses a multiwavelengt spectral (200-750 nm) for simultaneous measurement of nitrate, dissolved organic carbon (DOC) and total suspended solids (TSS). A global calibration based on a PLS (Partial Least Squares) regression is provided by the manufacturer as default configuration of the UV-visible spectrometer. We carried out a local calibration of the spectrometer based on nitrates and DOC concentrations analysed in the laboratory from daily manual sampling and sub-daily automatic sampling of flood events. TSS results are compared with 15 min turbidity records from a continuous turdidimeter (Ponsel). The results show a good correlation between laboratory data and spectrometer data both during basis flows periods and flood events. However, the local calibration gives better results than the global one. Nutrient fluxes estimates based on high and different low frequency time series (daily to monthly) are compared to discuss the implication for environmental monitoring strategies. Such

  5. Highly efficient nitrobenzene photoreduction over the amino acid-modified CdS-TiO2 nanostructures under visible light

    Directory of Open Access Journals (Sweden)

    Mohsen Padervand

    2017-01-01

    Full Text Available CdS-coupled TiO2 nanocrystals were prepared by the microemulsion-mediated solvothermal method at pretty low temperatures. The semiconductor nanocrystals were modified with tyrosine, phenyl alanine, glysine and glutamate aminoacids and then were characterized by BET, SEM, EDX, XRD, UV–Vis spectroscopy, and FTIR analysis methods. The specific surface area and the average pore diameter were found to be about 470 m2 g−1 and 2.8 nm, respectively. Moreover, the average size of the CdS-TiO2 particles was evaluated to be 28 nm. The results showed that the modification process with the aminoacids improves the adsorption capability and photoactivity of the samples. Among them, tyrosine was determined to be the best choice. According to the results, modification of CdS-TiO2 heterojunction photocatalyst with electron-donating groups is an efficient strategy to increase the photoreduction of nitroaromatic compounds. Reusability experiments were also carried out and confirmed the high capacity of the prepared samples for the photoconversion of nitrobenzene after being repeated for four times.

  6. High-accuracy measurements of snow Bidirectional Reflectance Distribution Function at visible and NIR wavelengths – comparison with modelling results

    Directory of Open Access Journals (Sweden)

    M. Dumont

    2010-03-01

    Full Text Available High-accuracy measurements of snow Bidirectional Reflectance Distribution Function (BRDF were performed for four natural snow samples with a spectrogonio-radiometer in the 500–2600 nm wavelength range. These measurements are one of the first sets of direct snow BRDF values over a wide range of lighting and viewing geometry. They were compared to BRDF calculated with two optical models. Variations of the snow anisotropy factor with lighting geometry, wavelength and snow physical properties were investigated. Results show that at wavelengths with small penetration depth, scattering mainly occurs in the very top layers and the anisotropy factor is controlled by the phase function. In this condition, forward scattering peak or double scattering peak is observed. In contrast at shorter wavelengths, the penetration of the radiation is much deeper and the number of scattering events increases. The anisotropy factor is thus nearly constant and decreases at grazing observation angles. The whole dataset is available on demand from the corresponding author.

  7. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    of Management. Published online: 1 May 2018. ABSTRACT. The article ... Achieving high financial performance is a priority for the country. .... developing at an advanced rate, and there is a hierarchy of entrepreneurial development types.

  8. Research Article Special Issue

    African Journals Online (AJOL)

    2016-07-16

    Jul 16, 2016 ... The companies with high level of customer satisfaction always are more powerful ... This article studies the impact of e-customer relationship .... 2- The multiple interactive value-added customer points with the organization.

  9. Viewer Makes Radioactivity "Visible"

    Science.gov (United States)

    Yin, L. I.

    1983-01-01

    Battery operated viewer demonstrates feasibility of generating threedimensional visible light simulations of objects that emit X-ray or gamma rays. Ray paths are traced for two pinhold positions to show location of reconstructed image. Images formed by pinholes are converted to intensified visible-light images. Applications range from radioactivity contamination surveys to monitoring radioisotope absorption in tumors.

  10. Highly efficient direct Z-scheme WO3/CdS-diethylenetriamine photocatalyst and its enhanced photocatalytic H2 evolution under visible light irradiation

    Science.gov (United States)

    Hu, Taiping; Li, Pengfei; Zhang, Jinfeng; Liang, Changhao; Dai, Kai

    2018-06-01

    Cadmium sulfide (CdS) has demonstrated great promise in artificial photocataytic hydrogen (H2) production. However, the serious photocorrosion hinders its effective interaction and real-life application. In this work, a typical direct Z-scheme WO3/CdS-diethylenetriamine (CdS-DETA) composite has been designed via facile in-situ solvothermal method, which exhibits excellent H2 production properties in visible light region. In this system, the inorganic-organic CdS-DETA nanobelts (NBs) possess enough active sites and large surface area for the encouraging nanojunction structure information. Furthermore, we also systematically calculated energy band structure and investigated charge transfer of the WO3/CdS-DETA by PL and photocurrent test, the results demonstrated that the suitable band gap matching between CdS-DETA and WO3 and high redox potential improve the separation of photogenerated holes and electrons, restraining intrinsic photocorrosion of CdS as well as improving the photocatalytic activity. 5%WO3/CdS-DETA presented the most outstanding H2 evolution rate (15522 μmol g-1 h-1), which is twice higher than that of pure CdS-DETA. WO3/CdS-DETA composites also presented high stability after three recycle H2 production experiment. Finally, direct Z-scheme photocatalytic mechanism is calculated.

  11. Heterogeneous Single-Atom Catalyst for Visible-Light-Driven High-Turnover CO2 Reduction: The Role of Electron Transfer.

    Science.gov (United States)

    Gao, Chao; Chen, Shuangming; Wang, Ying; Wang, Jiawen; Zheng, Xusheng; Zhu, Junfa; Song, Li; Zhang, Wenkai; Xiong, Yujie

    2018-03-01

    Visible-light-driven conversion of CO 2 into chemical fuels is an intriguing approach to address the energy and environmental challenges. In principle, light harvesting and catalytic reactions can be both optimized by combining the merits of homogeneous and heterogeneous photocatalysts; however, the efficiency of charge transfer between light absorbers and catalytic sites is often too low to limit the overall photocatalytic performance. In this communication, it is reported that the single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO 2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. As a result, the turnover number for CO production reaches a high value of 678 with an unprecedented turnover frequency of 3.77 min -1 , superior to those obtained with the state-of-the-art heterogeneous photocatalysts. This work provides fresh insights into the design of catalytic sites toward photocatalytic CO 2 conversion from the angle of single-atom catalysis and highlights the role of charge kinetics in bridging the gap between heterogeneous and homogeneous photocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of solar radiation (UV and visible) at high altitude on CAM-cycling and phenolic compound biosynthesis in Sedum album

    International Nuclear Information System (INIS)

    Bachereau, F.; Marigo, G.; Asta, J.

    1998-01-01

    The field experiment was carried out in order to compare the response of a CAM plant, Sedum album L., to solar radiation at a high altitude (2 100 m) with that at a low altitude location with respect to CAM and phenolic content. Treatment sites included (1) sun-exposed, low altitude, (2) sun-exposed, high altitude with different light treatments, including UV-B and UV-B + A screening, and (3) shade at high altitude. After a 70-day treatment period, CAM-cycling and phenolic compound content were analysed, and high altitude treatments were compared to the low altitude control. The sun-exposed low altitude control was characterized by CAM-cycling and a low phenolic compound content during the experiment. In plants transplanted to the high altitude, only the shaded group maintained a CAM-cycling and a phenolic compound content similar to those of the sun-exposed low altitude control. Samples under UV-B and UV-B + A filters showed similar responses, suggesting the absence of a specific UV-A radiation effect. The screening of UV-B or UV-B + A radiation allowed plants to partially maintain a CAM-cycling and induced a decrease in phenolic compound content. These responses under UV filters were, however, intermediate between those observed in sun-exposed and shaded groups. These results demonstrate a specific effect of radiation from both visible (400–800 nm) and UV-B (280–320 nm) bands on both CAM-cycling and phenolic biosynthesis in S. album L. plants. These light-dependent effects are discussed on a physiological basis and a possible interaction between CAM-cycling and phenolic metabolism is suggested. (author)

  13. Facile in situ synthesis of wurtzite ZnS/ZnO core/shell heterostructure with highly efficient visible-light photocatalytic activity and photostability

    Science.gov (United States)

    Xiao, Jian-Hua; Huang, Wei-Qing; Hu, Yong-sheng; Zeng, Fan; Huang, Qin-Yi; Zhou, Bing-Xin; Pan, Anlian; Li, Kai; Huang, Gui-Fang

    2018-02-01

    High photocatalytic activity and photostability are the pursuit of the goal for designing promising photocatalysts. Herein, using ZnO to encapsulate ZnS nanoparticles is proposed as an effective strategy to enhance photocatalytic activity and anti-photocorrosion. The ZnS/ZnO core/shell heterostructures are obtained via an annealing treatment of ZnS nanoparticles produced by a facile wet chemical approach. Due to its small size, the nascent cubic sphalerite ZnS (s-ZnS) converts into a hexagonal wurtzite ZnS (w-ZnS)/ZnO core/shell structure after annealing treatment. In situ oxidation leads to increasing ZnO, simultaneously decreasing the w-ZnS content in the resultant w-ZnS/ZnO with thermal annealing time. The w-ZnS/ZnO core/shell heterostructures show high photocatalytic activity, demonstrated by the photodegradation rate of methylene blue being up to ten-fold and seven-fold higher than that of s-ZnS under UV and visible light irradiation, respectively, and the high capability of degrading rhodamine B. The enhanced photocatalytic activity may be attributed to the large specific surface and improved charge carrier separation at the core/shell interface. Moreover, it displays high photostability owing to the protection of the ZnO shell, greatly inhibiting the photocorrosion of ZnS. This facile in situ oxidation is effective and easily scalable, providing opportunities for developing novel core/shell structure photocatalysts with high activity and photostability.

  14. [Street Outreach Offices: visibility, invisibility, and enhanced visibility].

    Science.gov (United States)

    Hallais, Janaína Alves da Silveira; Barros, Nelson Filice de

    2015-07-01

    This article discusses care for street people from a socio-anthropological perspective, using participant observation conducted with a team from a street outreach project. Based on observations, street people are historically viewed as marginal and rarely obtain access to health services, thus making them invisible to the Brazilian Unified National Health System. Brazil's National Policy for the Homeless provides for their access to health care, but such care is not always guaranteed in practice, because health services and professionals have little experience in dealing with homeless persons. The study concludes that enhanced visibility is needed to ensure care for people living on the street, establishing a therapeutic bond that deconstructs stigmatizing practice.

  15. HTTK R Package v1.4 - JSS Article on HTTK: R Package for High-Throughput Toxicokinetics

    Data.gov (United States)

    U.S. Environmental Protection Agency — httk: High-Throughput Toxicokinetics Functions and data tables for simulation and statistical analysis of chemical toxicokinetics ("TK") using data obtained from...

  16. Analyzing Visibility Configurations.

    Science.gov (United States)

    Dachsbacher, C

    2011-04-01

    Many algorithms, such as level of detail rendering and occlusion culling methods, make decisions based on the degree of visibility of an object, but do not analyze the distribution, or structure, of the visible and occluded regions across surfaces. We present an efficient method to classify different visibility configurations and show how this can be used on top of existing methods based on visibility determination. We adapt co-occurrence matrices for visibility analysis and generalize them to operate on clusters of triangular surfaces instead of pixels. We employ machine learning techniques to reliably classify the thus extracted feature vectors. Our method allows perceptually motivated level of detail methods for real-time rendering applications by detecting configurations with expected visual masking. We exemplify the versatility of our method with an analysis of area light visibility configurations in ray tracing and an area-to-area visibility analysis suitable for hierarchical radiosity refinement. Initial results demonstrate the robustness, simplicity, and performance of our method in synthetic scenes, as well as real applications.

  17. Two-dimensional porous architecture of protonated GCN and reduced graphene oxide via electrostatic self-assembly strategy for high photocatalytic hydrogen evolution under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Pu, Chenchen; Wan, Jun; Liu, Enzhou; Yin, Yunchao; Li, Juan; Ma, Yongning [School of Chemical Engineering, Northwest University, Xi’an 710069 (China); Fan, Jun, E-mail: fanjun@nwu.edu.cn [School of Chemical Engineering, Northwest University, Xi’an 710069 (China); Hu, Xiaoyun, E-mail: hxy3275@nwu.edu.cn [School of Physics, Northwest University, Xi’an 710069 (China)

    2017-03-31

    Highlights: • The protonated GCN (pGCN) is prepared by acidic cutting and hydrothermal process. • The pGCN coupled with rGO are synthesized via electrostatic self-assembly strategy. • The pGCN-5 wt% rGO is obtained with a high specific surface area of 115.64 m{sup 2}g{sup −1}. • The pGCN-5 wt% rGO photocatalysts exhibit superb photocatalytic reduction capacity. - Abstract: Herein, porous protonated graphitic carbon nitride (pGCN) is prepared from bulk g-C{sub 3}N{sub 4} (GCN) directly by acidic cutting and hydrothermal process. The holey structure not only provides a lot of bounds on the accelerated and photo induced charge transfer and thus reduce the aggregation, but also endows the GCN with more exposure to the active site. The pGCN is obtained with an increased band gap of 2.91 eV together with a higher specific surface area of 82.76 m{sup 2}g{sup −1}. Meanwhile, the positively charged GCN resulted from the protonation pretreatment is beneficial for improving the interaction with negatively charged GO sheets. Compared with GCN, pGCN-rGO displays a significant decrease of PL intensities and an apparently enhancement of visible-light absorption, resulting a lower charge recombination rate and a better light absorption. Besides, the enhanced charge separation is demonstrated by photoluminescence emission spectroscopy and the transient photocurrent measurement. The photocatalytic performance studies for the degradation of MB indicate that pGCN-rGO exhibits the highest adsorption ability towards dye molecules. In addition, the pGCN-5 wt% rGO composite shows the optimal photocatalytic activity, the photodegradation rate of MB is 99.4% after 80 min of irradiation and the H{sub 2} evolution performance up to 557 μmol g{sup −1}h{sup −1} under visible light, which is much higher than the other control samples.

  18. Controlled synthesis of {001} facets-dominated dye-sensitized BiOCl with high photocatalytic efficiency under visible-light irradiation

    International Nuclear Information System (INIS)

    Chen, Hongbin; Yu, Xiang; Zhu, Yi; Fu, Xionghui; Zhang, Yuanming

    2016-01-01

    High-quality BiOCl with {001} facets were successfully synthesized via a facile solvothermal method by controlling the volume ratio of ethanol (ET) and ethylene glycol (EG). The diameters of BiOCl nanosheets with {001} facets varied from 600 to 50 nm with the increase of EG content while the thickness nearly remained the same (∼20 nm). In the meantime, the morphologies of BiOCl turned into 3D hierarchical microspheres from 2D nanosheets. The 91.84 % {001} facets-exposed BiOCl nanosheets with diameter of 300–600 nm exhibited the best photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation on account of the strong adsorption property of the effective electron injection as well as the sequent reactive radical formation. More importantly, the RhB-sensitized BiOCl nanosheets showed effective photocatalytic property for breaking down methylene blue (MB) and methyl orange (MO) while RhB keeping almost intact until MB and MO had been photodegraded. It was found that the sensitizer radical cation (·RhB"+) could react with MB and MO and their suitable redox potential confirms that as well. These findings may provide a promising approach method for synthesizing other metal oxyhalide materials with controllable diameters of nanosheets and deepen our comprehending for the role of the semiconductor in the sensitization process.

  19. Simultaneous determination three phytosterol compounds, campesterol, stigmasterol and daucosterol in Artemisia apiacea by high performance liquid chromatography-diode array ultraviolet/visible detector

    Science.gov (United States)

    Lee, Jiwoo; Weon, Jin Bae; Yun, Bo-Ra; Eom, Min Rye; Ma, Choong Je

    2015-01-01

    Background: Artemisia apiacea is a traditional herbal medicine using treatment of eczema and jaundice in Eastern Asia, including China, Korea, and Japan. Objective: An accurate and sensitive analysis method using high performance liquid chromatography-diode array ultraviolet/visible detector and liquid chromatography–mass spectrometry for the simultaneous determination of three phytosterol compounds, campesterol, stigmasterol and daucosterol in A. apiacea was established. Materials and Methods: The analytes were separated on a Shiseido C18 column (5 μm, 4.6 mm I.D. ×250 mm) with gradient elution of 0.1% trifluoroacetic acid and acetonitrile. The flow rate was 1 mL/min and detection wavelengths were set at 205 and 254 nm. Results: Validation of the method was performed to demonstrate its linearity, precision and accuracy. The calibration curves showed good linearity (R2 > 0.9994). The limits of detection and limits of quantification were within the ranges 0.55–7.07 μg/mL and 1.67–21.44 μg/mL, respectively. And, the relative standard deviations of intra- and inter-day precision were <2.93%. The recoveries were found to be in the range of 90.03–104.91%. Conclusion: The developed method has been successfully applied to the analysis for quality control of campesterol, stigmasterol and daucosterol in A. apiacea. PMID:25829768

  20. Certification of caffeine reference material purity by ultraviolet/visible spectrophotometry and high-performance liquid chromatography with diode-array detection as two independent analytical methods.

    Science.gov (United States)

    Shehata, A B; Rizk, M S; Rend, E A

    2016-10-01

    Caffeine reference material certified for purity is produced worldwide, but no research work on the details of the certification process has been published in the literature. In this paper, we report the scientific details of the preparation and certification of pure caffeine reference materials. Caffeine was prepared by extraction from roasted and ground coffee by dichloromethane after heating in deionized water mixed with magnesium oxide. The extract was purified, dried, and bottled in dark glass vials. Stratified random selection was applied to select a number of vials for homogeneity and stability studies, which revealed that the prepared reference material is homogeneous and sufficiently stable. Quantification of caffeine purity % was carried out using a calibrated UV/visible spectrophotometer and a calibrated high-performance liquid chromatography with diode-array detection method. The results obtained from both methods were combined to drive the certified value and its associated uncertainty. The certified value of the reference material purity was found to be 99.86% and its associated uncertainty was ±0.65%, which makes the candidate reference material a very useful calibrant in food and drug chemical analysis. Copyright © 2016. Published by Elsevier B.V.

  1. Rapid modified QuEChERS method for pesticides detection in honey by high-performance liquid chromatography UV-visible

    Directory of Open Access Journals (Sweden)

    Elisabetta Bonerba

    2014-05-01

    Full Text Available The extensive use of pesticides in agriculture plays an important role in bees die-off and allows the presence of residues in hive products, particularly in honey. An accurate and reliable analytical method, based on QuEChERS extractive technique, has been developed for the quantitative determination by high-performance liquid chromatography UV-visible detector of 5 pesticides (Deltamethrin, Dimethoate, Imidacloprid, Acetamiprid, Chlorfenvinphos in honey. The method, according to Commission Directive 2002/63/EC and Regulation 882/2004/EC, provided excellent results with respect to linearity (correlation coefficient up to 0.993, limits of detection and quantification (0.005 and 0.01 μg/mL for Dimethoate, Deltamethrin and Chlorfenvinphos; 0.02 and 0.05 μg/mL for Acetamiprid and Imidacloprid, recovery values (86.4 to 96.3%, precision and relative expanded uncertainty of a measurement, demonstrating the conformity of the this method with the European directives. The proposed method was applied to 23 samples of Apulian honey. None of the investigated pesticides was detected in these samples.

  2. Certification of caffeine reference material purity by ultraviolet/visible spectrophotometry and high-performance liquid chromatography with diode-array detection as two independent analytical methods

    Directory of Open Access Journals (Sweden)

    A.B. Shehata

    2016-10-01

    Full Text Available Caffeine reference material certified for purity is produced worldwide, but no research work on the details of the certification process has been published in the literature. In this paper, we report the scientific details of the preparation and certification of pure caffeine reference materials. Caffeine was prepared by extraction from roasted and ground coffee by dichloromethane after heating in deionized water mixed with magnesium oxide. The extract was purified, dried, and bottled in dark glass vials. Stratified random selection was applied to select a number of vials for homogeneity and stability studies, which revealed that the prepared reference material is homogeneous and sufficiently stable. Quantification of caffeine purity % was carried out using a calibrated UV/visible spectrophotometer and a calibrated high-performance liquid chromatography with diode-array detection method. The results obtained from both methods were combined to drive the certified value and its associated uncertainty. The certified value of the reference material purity was found to be 99.86% and its associated uncertainty was ±0.65%, which makes the candidate reference material a very useful calibrant in food and drug chemical analysis.

  3. Fabrication and high visible-light-driven photocurrent response of g-C{sub 3}N{sub 4} film: The role of thiourea

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Lijuan; Chen, Shijian, E-mail: sjchen@cqu.edu.cn

    2016-12-15

    Highlights: • Thiourea promotes the growth and crystalline of the g-C{sub 3}N{sub 4} films on ITO. • Thiourea introduces S dopants into the g-C{sub 3}N{sub 4} films. • The obtained S-doped g-C{sub 3}N{sub 4} thin films show high VLD photocurrent response. • Three heterojunction structure types based on the g-C{sub 3}N{sub 4} films are proposed. - Abstract: We report on a convenient CVD fabrication of the uniform, compact and reproducible g-C{sub 3}N{sub 4} solid films on indium-tin oxide substrates. It is found that mixing quantitative thiourea into melamine as co-precursor prompts the deposition of greenish-yellow, transparent and smooth g-C{sub 3}N{sub 4} thin films. The thiourea apparently affects the crystalline, the surface morphologies and the energy band structures of g-C{sub 3}N{sub 4} films by modulating the polymerization process of the precursors, and simultaneously introduces S dopants into the g-C{sub 3}N{sub 4} films. Due to these roles of thiourea, the obtained S-doped g-C{sub 3}N{sub 4} films as a photoelectrode show a high and stable visible-light-driven photocurrent response. To further improve the photocurrent, the construction of three heterojunction structure types based on g-C{sub 3}N{sub 4} films is proposed and the corresponding charge transfer mechanisms are well discussed. The successful fabrication of high quality g-C{sub 3}N{sub 4} films in this work provides a footstone to construct the heterojunction film structures based on the carbon nitrides for the photoelectrochemical overall water splitting.

  4. Metal-Free 2D/2D Phosphorene/g-C3 N4 Van der Waals Heterojunction for Highly Enhanced Visible-Light Photocatalytic H2 Production.

    Science.gov (United States)

    Ran, Jingrun; Guo, Weiwei; Wang, Hailong; Zhu, Bicheng; Yu, Jiaguo; Qiao, Shi-Zhang

    2018-04-30

    The generation of green hydrogen (H 2 ) energy using sunlight is of great significance to solve the worldwide energy and environmental issues. Particularly, photocatalytic H 2 production is a highly promising strategy for solar-to-H 2 conversion. Recently, various heterostructured photocatalysts with high efficiency and good stability have been fabricated. Among them, 2D/2D van der Waals (VDW) heterojunctions have received tremendous attention, since this architecture can promote the interfacial charge separation and transfer and provide massive reactive centers. On the other hand, currently, most photocatalysts are composed of metal elements with high cost, limited reserves, and hazardous environmental impact. Hence, the development of metal-free photocatalysts is desirable. Here, a novel 2D/2D VDW heterostructure of metal-free phosphorene/graphitic carbon nitride (g-C 3 N 4 ) is fabricated. The phosphorene/g-C 3 N 4 nanocomposite shows an enhanced visible-light photocatalytic H 2 production activity of 571 µmol h -1 g -1 in 18 v% lactic acid aqueous solution. This improved performance arises from the intimate electronic coupling at the 2D/2D interface, corroborated by the advanced characterizations techniques, e.g., synchrotron-based X-ray absorption near-edge structure, and theoretical calculations. This work not only reports a new metal-free phosphorene/g-C 3 N 4 photocatalyst but also sheds lights on the design and fabrication of 2D/2D VDW heterojunction for applications in catalysis, electronics, and optoelectronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Exceptionally High Efficient Co-Co2P@N, P-Codoped Carbon Hybrid Catalyst for Visible Light-Driven CO2-to-CO Conversion.

    Science.gov (United States)

    Fu, Wen Gan

    2018-05-02

    Artificial photosynthesis has attracted wide attention, particularly the development of efficient solar light-driven methods to reduce CO2 to form energy-rich carbon-based products. Because CO2 reduction is an uphill process with a large energy barrier, suitable catalysts are necessary to achieve this transformation. In addition, CO2 adsorption on a catalyst and proton transfer to CO2 are two important factors for the conversion reaction,and catalysts with high surface area and more active sites are required to improve the efficiency of CO2 reduction. Here, we report a visible light-driven system for CO2-to-CO conversion that consists of a heterogeneous hybrid catalyst of Co and Co2P nanoparticles embedded in carbon nanolayers codoped with N and P (Co-Co2P@NPC) and a homogeneous Ru(II)-based complex photosensitizer. The average generation rate of CO of the system was up to 35,000 μmol h-1 g-1 with selectivity of 79.1% in 3 h. Linear CO production at an exceptionally high rate of 63,000 μmol h-1 g-1 was observed in the first hour of reaction. Inspired by this highly active catalyst, we also synthesized Co@NC and Co2P@NPC materials and explored their structure, morphology, and catalytic properties for CO2 photoreduction. The results showed that the nanoparticle size, partially adsorbed H2O molecules on the catalyst surface, and the hybrid nature of the systems influenced their photocatalytic CO2 reduction performance. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Visible spectroscopy on ASDEX

    International Nuclear Information System (INIS)

    Hofmann, J.V.

    1991-12-01

    In this report visible spectroscopy and impurity investigations on ASDEX are reviewed and several sets of visible spectra are presented. As a basis for identification of metallic impurity lines during plasma discharges spectra from a stainless steel - Cu arc have been recorded. In a next step a spectrum overview of ASDEX discharges is shown which reveals the dominating role of lines from light impurities like carbon and oxygen throughout the UV and visible range (2000 A ≤ λ ≤ 8000 A). Metallic impurity lines of neutrals or single ionized atoms are observed near localized surfaces. The dramatic effect of impurity reduction by boronization of the vessel walls is demonstrated in a few examples. In extension to some ivesti-gations already published, further diagnostic applications of visible spectroscopy are presented. Finally, the hardware and software system used on ASDEX are described in detail. (orig.)

  7. Process for the production of fuel combined articles for addition in block shaped high temperature fuel elements

    International Nuclear Information System (INIS)

    Hrovat, M.; Rachor, L.

    1976-01-01

    There is provided a process for the production of fuel compacts consisting of an isotropic, radiation-resistant graphite matrix of good heat conductivity having embedded therein coated fuel and/or fertile particles for insertion into high temperature fuel elements by providing the coated fuel and/or fertile particles with an overcoat of molding mixture consisting of graphite powder and a thermoplastic resin binder. The particles after the overcoating are provided with hardener and lubricant only on the surface and subsequently are compressed in a die heated to a constant temperature of about 150 0 C, hardened and discharged therefrom as finished compacts

  8. What makes a Scientific Article influential?

    NARCIS (Netherlands)

    H.P. van Dalen (Hendrik); K. Henkens

    2000-01-01

    textabstractIn this paper we examine, by means of a citation analysis, which factors influence the impact of articles published in demography journals between 1990 and 1992. Several quantifiable characteristics of the articles (characteristics with respect to authors, visibility, content and

  9. EDITORIAL: Special issue featuring articles arising from the 11th High-Tech Plasma Processes Conference Special issue featuring articles arising from the 11th High-Tech Plasma Processes Conference

    Science.gov (United States)

    Bruggeman, Peter; Degrez, Gérard; Delplancke, Marie-Paule; Gleizes, Alain

    2011-05-01

    The 11th High-Tech Plasma Processes Conference (HTPP) was held in Brussels, Belgium, 27 June-2 July, 2010. HTPP started as a thermal plasma conference and gradually expanded to include low-temperature plasmas. The conference was founded by Jacques Amouroux and Pierre Fauchais, and aims to bring together different scientific communities to facilitate contacts between science, technology and industry, providing a platform for the exploration of elementary processes and applications in and by plasmas. The first HTPP was held in Odeillo, France, in 1990. Since then it has been held every other year in different European cities: Paris, Aachen, Athens, Strasbourg, Saint-Petersburg, Patras and Brussels. The 11th HTPP conference was attended by 125 participants from 19 countries. The program involved 14 invited talks, 34 contributed talks, 72 posters and a software demonstration and hands-on session for plasma modelling. The 12th HTPP conference will be held 24-28 June 2012, in Bologna, Italy. A larger part of the contributions to the 11th HTPP has been published in the Journal of Physics: Conference Series (JPCS) volume 275, 2011. All invited speakers and other contributors, as selected by the Steering, Scientific and Organizing Committee, were invited to submit a paper based on their contributions for this special issue which is peer reviewed by the journal. Both this special issue and the JPCS volume aim to bring the 11th HTPP to a wider audience. The publications are a nice example of the broad topic range of the conference. The JPCS volume contains papers covering fundamental aspects on radiative processes of thermal plasmas, modelling of thermal arcs and non-thermal RF plasma jets, plasma diagnostics including flow and heat flux measurements of thermal plasmas, radical density measurements and laser-induced breakdown spectroscopy. The applications-oriented contributions of the JPCS volume include plasma spraying, synthesis of (nano-sized) materials, surface

  10. The extraction of gold nanoparticles from oat and wheat biomasses using sodium citrate and cetyltrimethylammonium bromide, studied by x-ray absorption spectroscopy, high-resolution transmission electron microscopy, and UV-visible spectroscopy.

    Science.gov (United States)

    Armendariz, Veronica; Parsons, Jason G; Lopez, Martha L; Peralta-Videa, Jose R; Jose-Yacaman, Miguel; Gardea-Torresdey, Jorge L

    2009-03-11

    Gold (Au) nanoparticles can be produced through the interaction of Au(III) ions with oat and wheat biomasses. This paper describes a procedure to recover gold nanoparticles from oat and wheat biomasses using cetyltrimethylammonium bromide or sodium citrate. Extracts were analyzed using UV-visible spectroscopy, high-resolution transmission electron microscopy (HRTEM), and x-ray absorption spectroscopy. The HRTEM data demonstrated that smaller nanoparticles are extracted first, followed by larger nanoparticles. In the fourth extraction, coating of chelating agents is visible on the extracted nanoparticles.

  11. The extraction of gold nanoparticles from oat and wheat biomasses using sodium citrate and cetyltrimethylammonium bromide, studied by x-ray absorption spectroscopy, high-resolution transmission electron microscopy, and UV-visible spectroscopy

    International Nuclear Information System (INIS)

    Armendariz, Veronica; Parsons, Jason G; Lopez, Martha L; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge L; Jose-Yacaman, Miguel

    2009-01-01

    Gold (Au) nanoparticles can be produced through the interaction of Au(III) ions with oat and wheat biomasses. This paper describes a procedure to recover gold nanoparticles from oat and wheat biomasses using cetyltrimethylammonium bromide or sodium citrate. Extracts were analyzed using UV-visible spectroscopy, high-resolution transmission electron microscopy (HRTEM), and x-ray absorption spectroscopy. The HRTEM data demonstrated that smaller nanoparticles are extracted first, followed by larger nanoparticles. In the fourth extraction, coating of chelating agents is visible on the extracted nanoparticles.

  12. A cocatalyst-free Eosin Y-sensitized p-type of Co₃O₄ quantum dot for highly efficient and stable visible-light-driven water reduction and hydrogen production.

    Science.gov (United States)

    Zhang, Ning; Shi, Jinwen; Niu, Fujun; Wang, Jian; Guo, Liejin

    2015-09-07

    Owing to the effect of energy band bending, p-type Co3O4 quantum dots sensitized by Eosin Y showed a high and stable photocatalytic activity (∼13,440 μmol h(-1) g(-1)(cat)) for water reduction and hydrogen production under visible-light irradiation without any cocatalyst.

  13. High performance sulfur, nitrogen and carbon doped mesoporous anatase–brookite TiO2 photocatalyst for the removal of microcystin-LR under visible light irradiation

    International Nuclear Information System (INIS)

    El-Sheikh, Said M.; Zhang, Geshan; El-Hosainy, Hamza M.; Ismail, Adel A.; O'Shea, Kevin E.; Falaras, Polycarpos; Kontos, Athanassios G.; Dionysiou, Dionysios D.

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis of tailor-designed C, N and S doped titania anatase–brookite nano-heterojunction photocatalyst. • Microcystin-LR was completely removed in the presence of doped sample under visible light. • The MC-LR degradation rate achieved by the doped sample was much better than that of un-doped sample under visible light. - Abstract: Carbon, nitrogen and sulfur (C, N and S) doped mesoporous anatase–brookite nano-heterojunction titania photocatalysts have been synthesized through a simple sol–gel method in the presence of triblock copolymer Pluronic P123. XRD and Raman spectra revealed the formation of anatase and brookite mixed phases. XPS spectra indicated the presence of C, N and S dopants. The TEM images demonstrated the formation of almost monodisperse titania nanoparticles with particle sizes of approximately 10 nm. N 2 isotherm measurements confirmed that both doped and undoped titania anatase–brookite materials have mesoporous structure. The photocatalytic degradation of the cyanotoxin microcystin-LR (MC-LR) has been investigated using these novel nanomaterials under visible light illumination. The photocatalytic efficiency of the mesoporous titania anatase–brookite photocatalyst dramatically increased with the addition of the C, N and S non-metal, achieving complete degradation (∼100%) of MC-LR. The results demonstrate the advantages of the synthetic approach and the great potential of the visible light activated C, N, and S doped titania photocatalysts for the treatment of organic micropollutants in contaminated waters under visible light

  14. Visible Light Responsive Catalyst for Air Water Purification Project

    Science.gov (United States)

    Wheeler, Raymond M.

    2014-01-01

    Investigate and develop viable approaches to render the normally UV-activated TIO2 catalyst visible light responsive (VLR) and achieve high and sustaining catalytic activity under the visible region of the solar spectrum.

  15. The chemistry of amine radical cations produced by visible light photoredox catalysis

    Directory of Open Access Journals (Sweden)

    Jie Hu

    2013-10-01

    Full Text Available Amine radical cations are highly useful reactive intermediates in amine synthesis. They have displayed several modes of reactivity leading to some highly sought-after synthetic intermediates including iminium ions, α-amino radicals, and distonic ions. One appealing method to access amine radical cations is through one-electron oxidation of the corresponding amines under visible light photoredox conditions. This approach and subsequent chemistries are emerging as a powerful tool in amine synthesis. This article reviews synthetic applications of amine radical cations produced by visible light photocatalysis.

  16. Use of Aerial high resolution visible imagery to produce large river bathymetry: a multi temporal and spatial study over the by-passed Upper Rhine

    Science.gov (United States)

    Béal, D.; Piégay, H.; Arnaud, F.; Rollet, A.; Schmitt, L.

    2011-12-01

    Aerial high resolution visible imagery allows producing large river bathymetry assuming that water depth is related to water colour (Beer-Bouguer-Lambert law). In this paper we aim at monitoring Rhine River geometry changes for a diachronic study as well as sediment transport after an artificial injection (25.000 m3 restoration operation). For that a consequent data base of ground measurements of river depth is used, built on 3 different sources: (i) differential GPS acquisitions, (ii) sounder data and (iii) lateral profiles realized by experts. Water depth is estimated using a multi linear regression over neo channels built on a principal component analysis over red, green and blue bands and previously cited depth data. The study site is a 12 km long reach of the by-passed section of the Rhine River that draws French and German border. This section has been heavily impacted by engineering works during the last two centuries: channelization since 1842 for navigation purposes and the construction of a 45 km long lateral canal and 4 consecutive hydroelectric power plants of since 1932. Several bathymetric models are produced based on 3 different spatial resolutions (6, 13 and 20 cm) and 5 acquisitions (January, March, April, August and October) since 2008. Objectives are to find the optimal spatial resolution and to characterize seasonal effects. Best performances according to the 13 cm resolution show a 18 cm accuracy when suspended matters impacted less water transparency. Discussions are oriented to the monitoring of the artificial reload after 2 flood events during winter 2010-2011. Bathymetric models produced are also useful to build 2D hydraulic model's mesh.

  17. The layered double hydroxide route to Bi-Zn co-doped TiO₂ with high photocatalytic activity under visible light.

    Science.gov (United States)

    Benalioua, Bahia; Mansour, Meriem; Bentouami, Abdelhadi; Boury, Bruno; Elandaloussi, El Hadj

    2015-05-15

    In this work, a co-doped Bi-Zn-TiO₂ photocatalist is synthesized by an original synthesis route of layered double hydroxide followed by heat treatment at 670 °C. After characterization the photocatalyst efficiency is estimated by the photo-discoloration of an anionic dye (indigo carmine) under visible light and compare to TiO₂-P25 as reference material. In this new photocatalyst, anatase and ZnO wurtzite are the only identified crystalline phase, rutile and Bi₂O₃ being undetected. Moreover, the binding energy of Bi determined (XPS analysis) is different from the one of Bi in Bi₂O₃. Compared to TiO₂-P25, the absorption is red shifted (UV-vis DRS) and the Bi-Zn-TiO₂ photocatalyst showed sorption capacity toward indigo carmine higher than that TiO₂-P25. The kinetics of the photo-discoloration is faster with Bi-Zn-TiO₂ than with TiO₂-P25. Indeed, a complete discoloration is obtained after 70 min and 120 min in the presence of Bi-Zn-TiO₂ and TiO₂-P25 respectively. The identification of the responsible species on photo-discoloration was carried out in the presence of different scavengers. The study showed that the first responsible is h(+) specie with a moderate contribution of superoxide anion radical and a minor contribution of the hydroxyl radical. The material showed high stability after five uses with the same rate of photo-discoloration. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The CeO{sub 2}/Ag{sub 3}PO{sub 4} photocatalyst with stability and high photocatalytic activity under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yanhua [School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003 (China); Zhao, Haozhu; Chen, Zhigang; Huang, Liying; Xu, Hui; Li, Huaming [School of the Environment, Institute for Energy Research, Jiangsu University, Zhenjiang, 212013 (China); Wang, Weiren [Department of Chemistry, Rice University, Houston, Texas, 77005 (United States)

    2016-09-15

    The CeO{sub 2}/Ag{sub 3}PO{sub 4} composite photocatalysts are synthesized by an in situ precipitation method. The XRD, FT-IR, XPS, TEM, EDS, and DRS are used to characterize the structure of the samples. The photocatalytic performance of the prepared samples is evaluated by the photocatalytic degradation of methylene blue (MB), rhodamine B (RhB), and ciprofloxacin (CIP). The results show that CeO{sub 2}/Ag{sub 3}PO{sub 4} hybrid materials exhibit much higher photocatalytic activity than the Ag{sub 3}PO{sub 4} alone. The optimal CeO{sub 2} content in CeO{sub 2}/Ag{sub 3}PO{sub 4} composites is found to be molar ratio 1 wt%. Photocurrent response of CeO{sub 2}/Ag{sub 3}PO{sub 4} (1 wt%) is about 1.5 times as high as that of the pure Ag{sub 3}PO{sub 4}. The increase of photocatalytic activity of CeO{sub 2}/Ag{sub 3}PO{sub 4} composites could be mainly attributed to the heterojunction between CeO{sub 2} and Ag{sub 3}PO{sub 4}. The trapping experiment has demonstrated that holes serve as the main active species for the degradation of MB under visible light irradiation. A photocatalytic mechanism is also proposed. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Predicting visibility of aircraft.

    Directory of Open Access Journals (Sweden)

    Andrew Watson

    Full Text Available Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO. In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration.

  20. Measuring visibility using smartphones

    Science.gov (United States)

    Friesen, Jan; Bialon, Raphael; Claßen, Christoph; Graffi, Kalman

    2017-04-01

    Spatial information on fog density is an important parameter for ecohydrological studies in cloud forests. The Dhofar cloud forest in Southern Oman exhibits a close interaction between the fog, trees, and rainfall. During the three month monsoon season the trees capture substantial amounts of horizontal precipitation from fog which increases net precipitation below the tree canopy. As fog density measurements are scarce, a smartphone app was designed to measure visibility. Different smartphone units use a variety of different parts. It is therefore important to assess the developed visibility measurement across a suite of different smartphones. In this study we tested five smartphones/ tablets (Google/ LG Nexus 5X, Huawei P8 lite, Huawei Y3, HTC Nexus 9, and Samsung Galaxy S4 mini) against digital camera (Sony DLSR-A900) and visual visibility observations. Visibility was assessed from photos using image entropy, from the number of visible targets, and from WiFi signal strength using RSSI. Results show clear relationships between object distance and fog density, yet a considerable spread across the different smartphone/ tablet units is evident.

  1. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-08-08

    Aug 8, 2017 ... The article considers problem of educational individualization within the .... learning in a higher educational institution, when professional preferences are ... determination of students' personal qualities correspondence to ... A high index by the “Modeling” criterionsuggeststhe ability to correlate models of ...

  2. Self-powered highly enhanced broad wavelength (UV to visible) photoresponse of ZnO@ZnO1-xSx@ZnS core-shell heterostructures.

    Science.gov (United States)

    Sarkar, Sanjit; Das Mahapatra, Ayon; Basak, Durga

    2018-08-01

    In the present scenario of energy crisis, it is inevitable to focus on the low powered or self-powered devices. Multi-spectral photoresponse is an additional advantage to the above feature. We have developed an efficient self-powered photodetector with broad wavelength detection range based on heterostructures of two wide band-gap materials ZnO and ZnS. More than two orders higher responsivity and 'ON/OFF' ratio has been observed in case of heterostructure sample as compared to pristine ZnO. On the basis of the controlled experimental results, it has been established that the interfacial surface engineering, can be useful to improve the visible response and a significant photovoltaic performance under visible light illumination can be achieved. Unlike the other recent reports on self-powered UV-visible photodetector, we have achieved two order higher visible response without compromising the UV photoresponse. Unprecedented broad wavelength photodetection in self-powered mode in the present study highlights the uniqueness and advantage of an interface in a core-shell heterostructure for photodetection applications. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. The Visible Hand of Research Performance Assessment

    Science.gov (United States)

    Hamann, Julian

    2016-01-01

    Far from allowing a governance of universities by the invisible hand of market forces, research performance assessments do not just measure differences in research quality, but yield themselves visible symptoms in terms of a stratification and standardization of disciplines. The article illustrates this with a case study of UK history departments…

  4. Visible Counterterrorism Measures in Urban Spaces

    DEFF Research Database (Denmark)

    Dalgaard-Nielsen, Anja; Laisen, Jesper; Wandorf, Charlotte

    2014-01-01

    factors impacting positively or negatively on the feelings of safety of Danish citizens, when being in a crowded place. Surprisingly, the response to security measures like fences, cameras, and uniformed guards was positive. More visible security apparently reinforced feelings of safety. This article...

  5. UVISS preliminary visibility analysis

    DEFF Research Database (Denmark)

    Betto, Maurizio

    1998-01-01

    The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part of the w......The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part...... of the work is also to setup the kernel of a software tool for the visibility analysis thatshould be easily expandable to consider more complex strucures for future activities.This analysis is part of the UVISS assessment study and it is meant to provide elementsfor the definition and the selection...

  6. Visible light-induced photocatalytic degradation of Reactive Blue-19 over highly efficient polyaniline-TiO2 nanocomposite: a comparative study with solar and UV photocatalysis.

    Science.gov (United States)

    Kalikeri, Shankramma; Kamath, Nidhi; Gadgil, Dhanashri Jayant; Shetty Kodialbail, Vidya

    2018-02-01

    Polyaniline-TiO 2 (PANI-TiO 2 ) nanocomposite was prepared by in situ polymerisation method. X-ray diffractogram (XRD) showed the formation of PANI-TiO 2 nanocomposite with the average crystallite size of 46 nm containing anatase TiO 2 . The PANI-TiO 2 nanocomposite consisted of short-chained fibrous structure of PANI with spherical TiO 2 nanoparticles dispersed at the tips and edge of the fibres. The average hydrodynamic diameter of the nanocomposite was 99.5 nm. The band gap energy was 2.1 eV which showed its ability to absorb light in the visible range. The nanocomposite exhibited better visible light-mediated photocatalytic activity than TiO 2 (Degussa P25) in terms of degradation of Reactive Blue (RB-19) dye. The photocatalysis was favoured under initial acidic pH, and complete degradation of 50 mg/L dye could be achieved at optimum catalyst loading of 1 g/L. The kinetics of degradation followed the Langmuir-Hinshelhood model. PANI-TiO 2 nanocomposite showed almost similar photocatalytic activity under UV and visible light as well as in the solar light which comprises of radiation in both UV and visible light range. Chemical oxygen demand removal of 86% could also be achieved under visible light, confirming that simultaneous mineralization of the dye occurred during photocatalysis. PANI-TiO 2 nanocomposites are promising photocatalysts for the treatment of industrial wastewater containing RB-19 dye.

  7. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene Gad

    2013-01-01

    This paper investigates managerial tactics of visualisation when a need to know and manage employees' values and attitudes is expressed. Using the Danish public school as a case study, we explore how school managers use teachers' emotions to render visible presumably invisible information about...... their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...

  8. White LED visible light communication technology research

    Science.gov (United States)

    Yang, Chao

    2017-03-01

    Visible light communication is a new type of wireless optical communication technology. White LED to the success of development, the LED lighting technology is facing a new revolution. Because the LED has high sensitivity, modulation, the advantages of good performance, large transmission power, can make it in light transmission light signal at the same time. Use white LED light-emitting characteristics, on the modulation signals to the visible light transmission, can constitute a LED visible light communication system. We built a small visible optical communication system. The system composition and structure has certain value in the field of practical application, and we also research the key technology of transmitters and receivers, the key problem has been resolved. By studying on the optical and LED the characteristics of a high speed modulation driving circuit and a high sensitive receiving circuit was designed. And information transmission through the single chip microcomputer test, a preliminary verification has realized the data transmission function.

  9. High-quality elliptical iron glycolate nanosheets: selective synthesis and chemical conversion into FexOy nanorings, porous nanosheets, and nanochains with enhanced visible-light photocatalytic activity

    Science.gov (United States)

    Tong, Guoxiu; Liu, Yun; Wu, Tong; Ye, Yucheng; Tong, Chaoli

    2015-10-01

    This paper describes an original and facile polyol-mediated solvothermal synthesis of elliptical iron glycolate nanosheets (IGNSs) combined with precursor thermal conversion into γ-Fe2O3 and α-Fe2O3/γ-Fe2O3 porous nanosheets (PNSs), α-Fe2O3 nanochains (NCs), and elliptical Fe3O4 nanorings (NRs). The IGNSs were produced via the oxidation-reduction and co-precipitation reactions in the presence of iron(iii) salts, ethylene glycol, polyethylene glycol, and ethylenediamine. Control over Fe3+ concentration, temperature, and time can considerably modulate the size and phase of the products. The IGNSs can be transformed to γ-Fe2O3 and α-Fe2O3/γ-Fe2O3 PNSs, α-Fe2O3 NCs, and elliptical Fe3O4 NRs by heat treatment under various annealing temperatures and ambiences. The PNSs and NCs exhibited high soft magnetic properties and coercivity, respectively. Visible-light photocatalytic activity toward RhB in the presence of H2O2 by PNSs and NCs was phase-, SBET, size-, porosity-, and local structure-dependent, following the order: α-Fe2O3 NCs > α-Fe2O3/γ-Fe2O3 PNSs > γ-Fe2O3 PNSs > IGNSs. In particular, α-Fe2O3/γ-Fe2O3 PNSs possessed significantly enhanced photocatalytic activity with good recyclability and could be conveniently separated by an applied magnetic field because of high magnetization. We believe that the as-prepared α-Fe2O3/γ-Fe2O3 PNSs have potential practical use in waste water treatment and microwave absorption.This paper describes an original and facile polyol-mediated solvothermal synthesis of elliptical iron glycolate nanosheets (IGNSs) combined with precursor thermal conversion into γ-Fe2O3 and α-Fe2O3/γ-Fe2O3 porous nanosheets (PNSs), α-Fe2O3 nanochains (NCs), and elliptical Fe3O4 nanorings (NRs). The IGNSs were produced via the oxidation-reduction and co-precipitation reactions in the presence of iron(iii) salts, ethylene glycol, polyethylene glycol, and ethylenediamine. Control over Fe3+ concentration, temperature, and time can

  10. High incorrect use of the standard error of the mean (SEM) in original articles in three cardiovascular journals evaluated for 2012.

    Science.gov (United States)

    Wullschleger, Marcel; Aghlmandi, Soheila; Egger, Marcel; Zwahlen, Marcel

    2014-01-01

    In biomedical journals authors sometimes use the standard error of the mean (SEM) for data description, which has been called inappropriate or incorrect. To assess the frequency of incorrect use of SEM in articles in three selected cardiovascular journals. All original journal articles published in 2012 in Cardiovascular Research, Circulation: Heart Failure and Circulation Research were assessed by two assessors for inappropriate use of SEM when providing descriptive information of empirical data. We also assessed whether the authors state in the methods section that the SEM will be used for data description. Of 441 articles included in this survey, 64% (282 articles) contained at least one instance of incorrect use of the SEM, with two journals having a prevalence above 70% and "Circulation: Heart Failure" having the lowest value (27%). In 81% of articles with incorrect use of SEM, the authors had explicitly stated that they use the SEM for data description and in 89% SEM bars were also used instead of 95% confidence intervals. Basic science studies had a 7.4-fold higher level of inappropriate SEM use (74%) than clinical studies (10%). The selection of the three cardiovascular journals was based on a subjective initial impression of observing inappropriate SEM use. The observed results are not representative for all cardiovascular journals. In three selected cardiovascular journals we found a high level of inappropriate SEM use and explicit methods statements to use it for data description, especially in basic science studies. To improve on this situation, these and other journals should provide clear instructions to authors on how to report descriptive information of empirical data.

  11. Simulating the z= 3.35 HI 21-cm Visibility Signal for the Ooty Wide ...

    Indian Academy of Sciences (India)

    This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately. All these have helped shorten the publication time and have improved the visibility of the articles. © 2017 Indian Academy of ...

  12. Visible Solid State Lasers

    NARCIS (Netherlands)

    Hikmet, R.A.M.

    2007-01-01

    Diode lasers can be found in various applications most notably in optical communication and optical storage. Visible lasers were until recently were all based on IR diode lasers. Using GaN, directly blue and violet emitting lasers have also been introduced to the market mainly in the area of optical

  13. Visible-light-assisted SLCs template synthesis of sea anemone-like Pd/PANI nanocomposites with high electrocatalytic activity for methane oxidation in acidic medium

    Science.gov (United States)

    Tan, De-Xin; Wang, Yan-Li

    2018-03-01

    Sea anemone-like palladium (Pd)/polyaniline (PANI) nanocomposites were synthesized via visible-light-assisted swollen liquid crystals (SLCs) template method. The resulting samples were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible (UV–vis) absorption spectroscopy and Fourier transform infrared (FT-IR) spectroscopy, respectively. The electrocatalytic properties of Pd/PANI nanocomposites modified glass carbon electrode (GCE) for methane oxidation were investigated by cycle voltammetry (CV) and chronoamperometry. Those dispersed sea anemone-like Pd/PANI nanocomposites had an average diameter of 320 nm. The obtained Pd nanoparticles with an average diameter of about 45 nm were uniformly distributed in PANI matrix. Sea anemone-like Pd/PANI nanocomposites exhibited excellent electrocatalytic activity and stability for oxidation of methane (CH4).

  14. Highly Efficient F, Cu doped TiO2 anti-bacterial visible light active photocatalytic coatings to combat hospital-acquired infections

    Science.gov (United States)

    Leyland, Nigel S.; Podporska-Carroll, Joanna; Browne, John; Hinder, Steven J.; Quilty, Brid; Pillai, Suresh C.

    2016-04-01

    Bacterial infections are a major threat to the health of patients in healthcare facilities including hospitals. One of the major causes of patient morbidity is infection with Staphylococcus aureus. One of the the most dominant nosocomial bacteria, Methicillin Resistant Staphylococcus aureus (MRSA) have been reported to survive on hospital surfaces (e.g. privacy window glasses) for up to 5 months. None of the current anti-bacterial technology is efficient in eliminating Staphylococcus aureus. A novel transparent, immobilised and superhydrophilic coating of titanium dioxide, co-doped with fluorine and copper has been prepared on float glass substrates. Antibacterial activity has demonstrated (by using Staphylococcus aureus), resulting from a combination of visible light activated (VLA) photocatalysis and copper ion toxicity. Co-doping with copper and fluorine has been shown to improve the performance of the coating, relative to a purely fluorine-doped VLA photocatalyst. Reductions in bacterial population of log10 = 4.2 under visible light irradiation and log10 = 1.8 in darkness have been achieved, compared with log10 = 1.8 under visible light irradiation and no activity, for a purely fluorine-doped titania. Generation of reactive oxygen species from the photocatalytic coatings is the major factor that significantly reduces the bacterial growth on the glass surfaces.

  15. Making Heat Visible

    Science.gov (United States)

    Goodhew, Julie; Pahl, Sabine; Auburn, Tim; Goodhew, Steve

    2015-01-01

    Householders play a role in energy conservation through the decisions they make about purchases and installations such as insulation, and through their habitual behavior. The present U.K. study investigated the effect of thermal imaging technology on energy conservation, by measuring the behavioral effect after householders viewed images of heat escaping from or cold air entering their homes. In Study 1 (n = 43), householders who received a thermal image reduced their energy use at a 1-year follow-up, whereas householders who received a carbon footprint audit and a non-intervention control demonstrated no change. In Study 2 (n = 87), householders were nearly 5 times more likely to install draught proofing measures after seeing a thermal image. The effect was especially pronounced for actions that addressed an issue visible in the images. Findings indicate that using thermal imaging to make heat loss visible can promote energy conservation. PMID:26635418

  16. Efficient resource allocation scheme for visible-light communication system

    Science.gov (United States)

    Kim, Woo-Chan; Bae, Chi-Sung; Cho, Dong-Ho; Shin, Hong-Seok; Jung, D. K.; Oh, Y. J.

    2009-01-01

    A visible-light communication utilizing LED has many advantagies such as visibility of information, high SNR (Signal to Noise Ratio), low installation cost, usage of existing illuminators, and high security. Furthermore, exponentially increasing needs and quality of LED have helped the development of visible-light communication. The visibility is the most attractive property in visible-light communication system, but it is difficult to ensure visibility and transmission efficiency simultaneously during initial access because of the small amount of initial access process signals. In this paper, we propose an efficient resource allocation scheme at initial access for ensuring visibility with high resource utilization rate and low data transmission failure rate. The performance has been evaluated through the numerical analysis and simulation results.

  17. Paradoxes of Visibility

    Directory of Open Access Journals (Sweden)

    Tarnay László

    2017-12-01

    Full Text Available The paper investigates two possible critical arguments following the pictorial turn. The first is formulated within ocularcentrism, the dominance of sight, and starts with the right to visibility as a general principle that governs today’s digital culture but gets twisted in special cases like the Auschwitz photos of the Shoa, the Abu Ghraib prison videos, or recently the website called Yolocaust. The second is conceived outside the visual culture and is meant to vindicate the other senses vis-à-vis the eyes. However, the argument is truncated here only to highlight the boomerang effect of the other senses: haptic vision. It is the case of visual perception when (a there is a lack of things to see and (b indeterminate synaesthesia: when vision intensifies the other senses in the embodied viewer. The two arguments converge upon a dialectic of the visible and the imaginable, which is formulated here as two paradoxes that the discussed examples transcend. By enforcing visibility at all costs where there is hardly anything recognizable to see, they lead to two diverging results. On the one hand, the meaning of “image” is extended toward the unimaginable, the traumatic experience, on the other hand, it is extended toward the invisible, the encounter with the radical Other.

  18. The benefits of visibility

    International Nuclear Information System (INIS)

    Krupnick, A.; DeWitt, D.

    1994-01-01

    The benefits of visibility improvement (or the damages with additional degradation) refer to increases (or decreases) in utility obtained in three different dimensions. The first of these is associated with the nature of the visibility change. Visual range may be improved so that features of an area become more distinct or the sky becomes clearer. Alternatively, normal features of an area may be marred, say by the site of a power plant or its plume (called plume blight). The second dimension is the location of the change: in an urban area, in a rural setting, or in a recreational area or area of particular beauty, such as the Grand Canyon. The third dimension is the type of value: use or non-use. Thus, a person who visits the Grand Canyon (or may visit it in the future) may hold use values for improving his view of the Canyon or its surroundings and may also old non-use values for improved visibility (whether for altruistic or other reasons) irrespective of present or planned visits. In all, therefore, there are 12 possible combinations of the elements in these three dimension, each of which is logically distinct from the others and which demands attention in the literature to derive willingness to pay (WTP)

  19. The benefits of visibility

    Energy Technology Data Exchange (ETDEWEB)

    Krupnick, A; DeWitt, D

    1994-07-01

    The benefits of visibility improvement (or the damages with additional degradation) refer to increases (or decreases) in utility obtained in three different dimensions. The first of these is associated with the nature of the visibility change. Visual range may be improved so that features of an area become more distinct or the sky becomes clearer. Alternatively, normal features of an area may be marred, say by the site of a power plant or its plume (called plume blight). The second dimension is the location of the change: in an urban area, in a rural setting, or in a recreational area or area of particular beauty, such as the Grand Canyon. The third dimension is the type of value: use or non-use. Thus, a person who visits the Grand Canyon (or may visit it in the future) may hold use values for improving his view of the Canyon or its surroundings and may also old non-use values for improved visibility (whether for altruistic or other reasons) irrespective of present or planned visits. In all, therefore, there are 12 possible combinations of the elements in these three dimension, each of which is logically distinct from the others and which demands attention in the literature to derive willingness to pay (WTP)

  20. Article and process for producing an article

    Science.gov (United States)

    Lacy, Benjamin Paul; Jacala, Ariel Caesar Prepena; Kottilingam, Srikanth Chandrudu; Schick, David Edward

    2017-10-24

    An article and a process of producing an article are provided. The article includes a base material, a cooling feature arrangement positioned on the base material, the cooling feature arrangement including an additive-structured material, and a cover material. The cooling feature arrangement is between the base material and the cover material. The process of producing the article includes manufacturing a cooling feature arrangement by an additive manufacturing technique, and then positioning the cooling feature arrangement between a base material and a cover material.

  1. Are reports of randomized controlled trials improving over time? A systematic review of 284 articles published in high-impact general and specialized medical journals.

    Science.gov (United States)

    To, Matthew J; Jones, Jennifer; Emara, Mohamed; Jadad, Alejandro R

    2013-01-01

    Inadequate reporting undermines findings of randomized controlled trials (RCTs). This study assessed and compared articles published in high-impact general medical and specialized journals. Reports of RCTs published in high-impact general and specialized medical journals were identified through a search of MEDLINE from January to March of 1995, 2000, 2005, and 2010. Articles that provided original data on adult patients diagnosed with chronic conditions were included in the study. Data on trial characteristics, reporting of allocation concealment, quality score, and the presence of a trial flow diagram were extracted independently by two reviewers, and discrepancies were resolved by consensus or independent adjudication. Descriptive statistics were used for quantitative variables. Comparisons between general medical and specialized journals, and trends over time were performed using Chi-square tests. Reports of 284 trials were analyzed. There was a significantly higher proportion of RCTs published with adequate reporting of allocation concealment (p = 0.003), presentation of a trial flow diagram (pgeneral medical journals had higher quality scores than those in specialized journals (p = 0.001), reported adequate allocation concealment more often (p = 0.013), and presented a trial flow diagram more often (pjournals over the last fifteen years. These improvements are likely attributed to concerted international efforts to improve reporting quality such as CONSORT. There is still much room for improvement, especially among specialized journals.

  2. Characterization of the Edges and Contrasts in a digital image with the variation of the Parameters of the High-pass Filters used in the Estimation of Atmospheric Visibility

    Directory of Open Access Journals (Sweden)

    Martha C. Guzmán-Zapata

    2013-11-01

    Full Text Available This paper considers the edges and contrasts obtained with high-pass filters used in the estimation of daytime atmospheric visibility from digital images, and the behavior of these edges and contrasts is characterized by varying the parameters of high-pass filters such as the Ideal, Gaussian, and Homomorphic-Gaussian. A synthetic image of regions with different contrasts is used to apply different filters, then, we define an index to measure the quality of the edges obtained in the filtered image and it is used to analyze the results. The results show that both, the filter selection and the selection of its parameters: affects the characteristics and quality of the detected edges in the filtered image, also determine the amount of noise that the filter added to the image (artifacts that were not present in the original image, and also establish if achieved, or not, the edge detection. The results also show that the edge quality index reaches maximum values at certain combinations of the filters parameters, which means that some combinations of parameters reduce situations distorting the edges and distorting atmospheric visibility measures based on the Fourier transform. So these parameters which provide maximum quality edges are established as suitable for use in visibility measurement.

  3. Proton and electron impact on molecular and atomic oxygen: I. High resolution fluorescence spectra in the visible and VUV spectral range and emission cross-sections for dissociative ionisation and excitation of O2

    International Nuclear Information System (INIS)

    Wilhelmi, O.; Schartner, K.H.

    2000-01-01

    For pt.II see ibid., vol.11, p.45-58, 2000. Molecular oxygen O 2 was dissociated in collisions with protons and electrons in the intermediate velocity range (p + -energies: 17-800 keV, e - -energies: 0.2-2 keV). Fluorescence from excited atomic and singly ionised fragments and from singly ionised molecules was detected in the VUV and in the visible and near UV spectral range. Highly resolved spectra are presented for the VUV (46-131 nm) and the near UV/visible (340-605 nm) spectral range. Absolute emission cross-sections have been determined for dissociative ionisation and excitation leading to fluorescence in the VUV. Results are compared with published data. (orig.)

  4. Article and method of forming an article

    Science.gov (United States)

    Lacy, Benjamin Paul; Kottilingam, Srikanth Chandrudu; Dutta, Sandip; Schick, David Edward

    2017-12-26

    Provided are an article and a method of forming an article. The method includes providing a metallic powder, heating the metallic powder to a temperature sufficient to joint at least a portion of the metallic powder to form an initial layer, sequentially forming additional layers in a build direction by providing a distributed layer of the metallic powder over the initial layer and heating the distributed layer of the metallic powder, repeating the steps of sequentially forming the additional layers in the build direction to form a portion of the article having a hollow space formed in the build direction, and forming an overhang feature extending into the hollow space. The article includes an article formed by the method described herein.

  5. NiS and MoS2 nanosheet co-modified graphitic C3N4 ternary heterostructure for high efficient visible light photodegradation of antibiotic.

    Science.gov (United States)

    Lu, Xuejun; Wang, Yu; Zhang, Xinyi; Xu, Guangqing; Wang, Dongmei; Lv, Jun; Zheng, Zhixiang; Wu, Yucheng

    2018-01-05

    The development of efficient solar driven catalytic system for the degradation of antibiotics has become increasingly important in environmental protection and remediation. Non-noble-metal NiS and MoS 2 nanosheet co-modified graphitic C 3 N 4 ternary heterostructure has been synthesized via a facile combination of hydrothermal and ultrasound method, and the ternary heterostructure has been utilized for photocatalytic degradation of antibiotic agents. The antibiotics of ciprofloxacin (CIP) and tetracycline hydrochloride (TC) were photodegraded by the hybrid under the visible light. The optimal photodegradation rate of the ternary heterostructure reaches about 96% after 2h irradiation, which is 2.1 times higher than that of pure g-C 3 N 4 for TC degradation. The photocatalytic degradation rates of the ternary heterostructure for both CIP and TC obey the pseudo-first-order kinetic model. The enhanced visible light adsorption and charge separation efficiency contribute to the photocatalytic performance of the ternary heterostructure. This work provides new insights and pathways by which efficient degradation of antibiotics can be achieved and will stimulate further studies in this important field. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Highly antibacterial activity of N-doped TiO{sub 2} thin films coated on stainless steel brackets under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi [Department of Orthodontics, School of Stomatology, Lanzhou University, Lanzhou 730000 (China); Liu, Bin [Department of Materials Science, School of Physical Science and Technology, Lanzhou University, Lanzhou 730000 (China); Cao, Baocheng, E-mail: caobch@lzu.edu.cn [Department of Orthodontics, School of Stomatology, Lanzhou University, Lanzhou 730000 (China)

    2014-08-01

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO{sub 2} thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  7. Synthesis of Nb doped TiO2 nanotube/reduced graphene oxide heterostructure photocatalyst with high visible light photocatalytic activity

    Science.gov (United States)

    Niu, Xiaoyou; Yan, Weijing; Zhao, Hongli; Yang, Jingkai

    2018-05-01

    Limited by the narrowed photoresponse range and unsatisfactory recombination of photoinduced electron-hole pairs, the photocatalytic efficiency of TiO2 is still far below what is expected. Here, we initially doped TiO2 nanotubes (TNTS) by transition metal ion Nb, then it is coupled with reduced graphene oxide (rGO) to construct a heterostructure photocatalyst. The defect state presented in TiO2 leading to the formation of localized midgap states (MS) in the bandgap, which regulating the band structure of TiO2 and extending the optical absorption to visible light region. The internal charge transport and transfer behavior analyzed by electrochemical impedance spectroscopy (EIS) reveal that the coupling of rGO with TNTS results in the formation of electron transport channel in the heterostructure, which makes a great contribution to the photoinduced charge separation. As expected, the Nb-TNTS/rGO exhibits a stable and remarkably enhanced photocatalytic activity in the visible-light irradiation degradation of methylene blue (MB), up to ∼5 times with respect to TNTS, which is attributed to the effective inhibition of charge recombination, the reduction of bandgap and higher redox potential, as well as the great adsorptivity.

  8. Highly antibacterial activity of N-doped TiO2 thin films coated on stainless steel brackets under visible light irradiation

    International Nuclear Information System (INIS)

    Cao, Shuai; Liu, Bo; Fan, Lingying; Yue, Ziqi; Liu, Bin; Cao, Baocheng

    2014-01-01

    In this study, the radio frequency (RF) magnetron sputtering method was used to prepare a TiO 2 thin film on the surface of stainless steel brackets. Eighteen groups of samples were made according to the experimental parameters. The crystal structure and surface morphology were characterized by X-ray diffraction, and scanning electron microscopy, respectively. The photocatalytic properties under visible light irradiation were evaluated by measuring the degradation ratio of methylene blue. The sputtering temperature was set at 300 °C, and the time was set as 180 min, the ratio of Ar to N was 30:1, and annealing temperature was set at 450 °C. The thin films made under these parameters had the highest visible light photocatalytic activity of all the combinations of parameters tested. Antibacterial activities of the selected thin films were also tested against Lactobacillus acidophilus and Candida albicans. The results demonstrated the thin film prepared under the parameters above showed the highest antibacterial activity.

  9. Young science journalism: writing popular scientific articles may contribute to an increase of high-school students' interest in the natural sciences

    Science.gov (United States)

    Simon, Uwe K.; Steindl, Hanna; Larcher, Nicole; Kulac, Helga; Hotter, Annelies

    2016-03-01

    Far too few high-school students choose subjects from the natural sciences (NaSc) for their majors in many countries. Even fewer study biology, chemistry or physics at university. Those, that do, often lack training to present and discuss scientific results and ideas in texts. To meet these challenges the center for didactics of biology of Graz University has set up the program Young Science Journalism. This new workshop-based interdisciplinary concept was tested in an exploratory study with grade 10 students of one Austrian high school, engaging both the biology and the German teacher of the class. It was our aim to raise students' interest in the NaSc by encouraging them to write popular scientific articles about self-chosen topics, and to help them improve their writing competence. In this paper we focus on interest development through writing. Results from this pilot study were promising. Using a mixed-method approach (comparing pre- and post-test questionnaires and semi-structured interviews from different time points analyzed qualitatively), we found that almost all students valued the project-related work highly. Most of them showed higher interest in the NaSc at project end with girls, in average, seeming to profit more from project participation. We thus recommend integrating such writing tasks into school curricula to increase students' interest in NaSc or to even create new interest. Additionally, we introduce a network presentation of questionnaire data as a powerful tool to visualize the effect of an intervention on individual students and student profile groups. This paper is part of a series accompanying the Austrian Young Science Journalism program. Additional Supporting Information may be found in the online version of this article at the publisher's web-site.

  10. Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction as a highly efficient and stable visible light photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chengbin, E-mail: chem_cbliu@hnu.edu.cn [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Cao, Chenghao [State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Luo, Xubiao [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); Luo, Shenglian [Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle, Nanchang Hangkong University, Nanchang 330063 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China)

    2015-03-21

    Graphical abstract: A unique Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction was fabricated by simple electrochemical method. The heterostructures exhibit high photocatalytic activity and excellent recycling performance. - Highlights: • Ag-bridged Ag{sub 2}O nanowire network self-stability structure. • Ag{sub 2}O nanowire network/TiO{sub 2} nanotube p–n heterojunction. • High visible light photocatalytic activity. • Highly stable recycling performance. - Abstract: A unique Ag-bridged Ag{sub 2}O nanowire network/TiO{sub 2} nanotube array p–n heterojunction (Ag–Ag{sub 2}O/TiO{sub 2} NT) was fabricated by simple electrochemical method. Ag nanoparticles were firstly electrochemically deposited onto the surface of TiO{sub 2} NT and then were partly oxidized to Ag{sub 2}O nanowires while the rest of Ag mother nanoparticles were located at the junctions of Ag{sub 2}O nanowire network. The Ag–Ag{sub 2}O/TiO{sub 2} NT heterostructure exhibited strong visible-light response, effective separation of photogenerated carriers, and high adsorption capacity. The integration of Ag–Ag{sub 2}O self-stability structure and p–n heterojunction permitted high and stable photocatalytic activity of Ag–Ag{sub 2}O/TiO{sub 2} NT heterostructure photocatalyst. Under 140-min visible light irradiation, the photocatalytic removal efficiency of both dye acid orange 7 (AO7) and industrial chemical p-nitrophenol (PNP) over Ag–Ag{sub 2}O/TiO{sub 2} NT reached nearly 100% much higher than 17% for AO7 or 13% for PNP over bare TiO{sub 2} NT. After 5 successive cycles under 600-min simulated solar light irradiation, Ag–Ag{sub 2}O/TiO{sub 2} NT remained highly stable photocatalytic activity.

  11. A climatology of visible surface reflectance spectra

    International Nuclear Information System (INIS)

    Zoogman, Peter; Liu, Xiong; Chance, Kelly; Sun, Qingsong; Schaaf, Crystal; Mahr, Tobias; Wagner, Thomas

    2016-01-01

    We present a high spectral resolution climatology of visible surface reflectance as a function of wavelength for use in satellite measurements of ozone and other atmospheric species. The Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument is planned to measure backscattered solar radiation in the 290–740 nm range, including the ultraviolet and visible Chappuis ozone bands. Observation in the weak Chappuis band takes advantage of the relative transparency of the atmosphere in the visible to achieve sensitivity to near-surface ozone. However, due to the weakness of the ozone absorption features this measurement is more sensitive to errors in visible surface reflectance, which is highly variable. We utilize reflectance measurements of individual plant, man-made, and other surface types to calculate the primary modes of variability of visible surface reflectance at a high spectral resolution, comparable to that of TEMPO (0.6 nm). Using the Moderate-resolution Imaging Spectroradiometer (MODIS) Bidirection Reflectance Distribution Function (BRDF)/albedo product and our derived primary modes we construct a high spatial resolution climatology of wavelength-dependent surface reflectance over all viewing scenes and geometries. The Global Ozone Monitoring Experiment–2 (GOME-2) Lambertian Equivalent Reflectance (LER) product provides complementary information over water and snow scenes. Preliminary results using this approach in multispectral ultraviolet+visible ozone retrievals from the GOME-2 instrument show significant improvement to the fitting residuals over vegetated scenes. - Highlights: • Our goals was visible surface reflectance for satellite trace gas measurements. • Captured the range of surface reflectance spectra through EOF analysis. • Used satellite surface reflectance products for each given scene to anchor EOFs. • Generated a climatology of time/geometry dependent surface reflectance spectra. • Demonstrated potential to

  12. On court interpreters' visibility

    DEFF Research Database (Denmark)

    Dubslaff, Friedel; Martinsen, Bodil

    of the service they receive. Ultimately, the findings will be used for training purposes. Future - and, for that matter, already practising - interpreters as well as the professional users of interpreters ought to take the reality of the interpreters' work in practice into account when assessing the quality...... on the interpreter's interpersonal role and, in particular, on signs of the interpreter's visibility, i.e. active co-participation. At first sight, the interpreting assignment in question seems to be a short and simple routine task which would not require the interpreter to deviate from the traditional picture...

  13. Making Invisible Forces Visible

    DEFF Research Database (Denmark)

    Ratner, Helene Gad

    2013-01-01

    their 'true' attitudes and values. The paper draws on theories of affect as well as actor-network theory to analyse three incidents where managers turn their interpretations of teachers' emotions into such information. These incidents suggest that the efforts to render employees' attitudes and values visible...... install a normative emotional scale where an ideal employee displays emotional investment and self-control. This has implications, not only for employees who are expected to exhibit the 'right' emotions, but also for management, which comes to depend on transient emotions and co-presence in situations...

  14. ac superconducting articles

    International Nuclear Information System (INIS)

    Meyerhoff, R.W.

    1977-01-01

    A noval ac superconducting cable is described. It consists of a composite structure having a superconducting surface along with a high thermally conductive material wherein the superconducting surface has the desired physical properties, geometrical shape and surface finish produced by the steps of depositing a superconducting layer upon a substrate having a predetermined surface finish and shape which conforms to that of the desired superconducting article, depositing a supporting layer of material on the superconducting layer and removing the substrate, the surface of the superconductor being a replica of the substrate surface

  15. CTAB-Assisted Hydrothermal Synthesis of Bi2Sn2O7 Photocatalyst and Its Highly Efficient Degradation of Organic Dye under Visible-Light Irradiation

    Directory of Open Access Journals (Sweden)

    Weicheng Xu

    2013-01-01

    Full Text Available Pyrochlore-type Bi2Sn2O7 (BSO nanoparticles have been prepared by a hydrothermal method assisted with a cationic surfactant cetyltrimethylammonium bromide (CTAB. These BSO products were characterized by powder X-ray diffraction (XRD, infrared spectroscopy (IR, scanning electron microscopy (SEM, transmission electron microscopy (TEM, Brunauer-Emmett-Teller (BET, and UV-visible diffuse reflectance spectroscopy (DRS. The results indicated that CTAB alters the surface parameters and the morphology and enhances the photoinduced charge separation rate of BSO. The photocatalytic degradation test using rhodamine B as a model pollutant showed that the photocatalytic activity of the BSO assisted with CTAB was two times that of the reference BSO. Close investigation revealed that the size, the band gap, the structure, and the existence of impurity level played an important role in the photocatalytic activities.

  16. Surface treatment of ceramic articles

    International Nuclear Information System (INIS)

    Komvopoulos, K.; Brown, I.G.; Wei, B.; Anders, S.; Anders, A.; Bhatia, C.S.

    1998-01-01

    A process is disclosed for producing an article with improved ceramic surface properties including providing an article having a ceramic surface, and placing the article onto a conductive substrate holder in a hermetic enclosure. Thereafter a low pressure ambient is provided in the hermetic enclosure. A plasma including ions of solid materials is produced the ceramic surface of the article being at least partially immersed in a macroparticle free region of the plasma. While the article is immersed in the macroparticle free region, a bias of the substrate holder is biased between a low voltage at which material from the plasma condenses on the surface of the article and a high negative voltage at which ions from the plasma are implanted into the article. 15 figs

  17. Alcohol consumption, smoking and development of visible age-related signs: a prospective cohort study.

    Science.gov (United States)

    Schou, Anne L; Mølbak, Marie-Louise; Schnor, Peter; Grønbæk, Morten; Tolstrup, Janne S

    2017-12-01

    Visible age-related signs indicate biological age, as individuals that appear old for their age are more likely to be at poor health, compared with people that appear their actual age. The aim of this study was to investigate whether alcohol and smoking are associated with four visible age-related signs (arcus corneae, xanthelasmata, earlobe crease and male pattern baldness). We used information from 11 613 individuals in the Copenhagen City Heart Study (1976-2003). Alcohol intake, smoking habits and other lifestyle factors were assessed prospectively and visible age-related signs were inspected during subsequent examinations. The risk of developing arcus corneae, earlobe crease and xanthelasmata increased stepwise with increased smoking as measured by pack-years. For alcohol consumption, a high intake was associated with the risk of developing arcus corneae and earlobe crease, but not xanthelasmata. High alcohol consumption and smoking predict development of visible age-related signs. This is the first prospective study to show that heavy alcohol use and smoking are associated with generally looking older than one's actual age. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  18. Publishing International Counseling Articles

    Science.gov (United States)

    Hohenshil, Thomas H.; Amundson, Norman E.

    2011-01-01

    This article begins with a rationale for including international articles in the "Journal of Counseling & Development." Then, 2 general categories of international articles are described. First are articles that provide a general overview of counseling in a particular country. The 2nd category is more general and might involve international…

  19. Article and method for making an article

    Energy Technology Data Exchange (ETDEWEB)

    Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

    2018-04-03

    An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of depositing a metal alloy powder to form an initial layer including at least one aperture, melting the metal alloy powder with a focused energy source to transform the powder layer to a sheet of metal alloy, sequentially depositing an additional layer of the metal alloy powder to form a layer including at least one aperture corresponding to the at least one aperture in the initial layer, melting the additional layer of the metal alloy powder with the focused energy source to increase the sheet thickness, and repeating the steps of sequentially depositing and melting the additional layers of metal alloy powder until a structure including at least one aperture having a predetermined profile is obtained. The structure is attached to a substrate to make the article.

  20. Article and method for making an article

    Science.gov (United States)

    Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

    2018-04-03

    An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of providing a metal alloy powder; forming an initial layer with the metal alloy powder, the initial layer having a preselected thickness and a preselected shape, the preselected shape including at least one aperture; sequentially forming an additional layer over the initial layer with the metal alloy powder, the additional layer having a second preselected thickness and a second preselected shape, the second preselected shape including at least one aperture corresponding to the at least one aperture in the initial layer; and joining the additional layer to the initial layer, forming a structure having a predetermined thickness, a predetermined shape, and at least one aperture having a predetermined profile. The structure is attached to a substrate to make the article.

  1. Research Article Special Issue

    African Journals Online (AJOL)

    2017-10-05

    Oct 5, 2017 ... rk was started with designing several U-shaped POF model tha ... ot in phase while the irradiance is the radiant flux (power) receive ..... methanol water mixtures in the visible wavelength area using fibre-optic evanescent field.

  2. Visible but Unseen?

    DEFF Research Database (Denmark)

    Torkilsheyggi, Arnvør Martinsdóttir á; Hertzum, Morten

    2015-01-01

    Studies have shown that whiteboards support much cooper-ative work by for example strengthening awareness, im-proving communication, and reducing mental workload. In line with these predominantly positive findings, an emer-gency department (ED) turned to its whiteboard to improve the coordination...... of its work with blood tests. We investi-gate this use of the whiteboard through observations and informal interviews in the ED and analyze the ability of the whiteboard to support coordination and awareness in the work with blood tests. Our findings show limitations in the ability of the whiteboard...... to support awareness in a setting where the users are (locally) mobile, specifically in regard to information that requires continuous monitoring. We do however also find that the whiteboard safeguarded the work with blood tests against some risks by making blood-test information socially visible....

  3. Well-crystallized ZnCo{sub 2}O{sub 4} nanosheets as a new-style support of Au catalyst for high efficient CO preferential oxidation in H{sub 2} stream under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Kai [Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002 (China); School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China); Zhang, Yujuan; Meng, Chao [Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002 (China); Cao, FangFang [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China); State Key Laboratory of Advanced Technology for Float Glass Technology, Bengbu 233000 (China); Chen, Xun; Fu, Xianzhi [Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002 (China); Dai, Wenxin, E-mail: daiwenxin@fzu.edu.cn [Research Institute of Photocatalysis, State Key Laboratory of Photocatalysis on Energy and Environment, Fuzhou University, Fuzhou 350002 (China); Yu, Changlin, E-mail: yuchanglinjx@163.com [School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, Jiangxi (China)

    2017-01-01

    Highlights: • Spinel ZnCo{sub 2}O{sub 4} nanosheets were fabricated by a facile template-free wet chemical method. • ZnCo{sub 2}O{sub 4} nanosheet supported Au catalyst exhibited a good stability for oxidizing CO. • Visible light could promote the adsorption and activation of CO and O{sub 2} on Au/ZnCo{sub 2}O{sub 4}. • A efficient charge transfer occurred on the interface of Au and ZnCo{sub 2}O{sub 4}. - Abstract: A kind of high dispersed gold catalyst supported on the spinel ZnCo{sub 2}O{sub 4} nanosheets was readily fabricated by a facile template-free wet chemical method for CO oxidation in H{sub 2}-rich streams at room temperature under visible light irradiation or not, which was found to be a high performance catalyst. As verified by X-ray powder diffractometry (XRD), Raman spectra, N{sub 2} adsorption–desorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscope (XPS), photoelectrochemical measurement and photoluminescence (PL) spectra results, the contribution of high crystallinity, the enhanced mass and charge transport, the longer lifetime of surface electrons as well as the optical absorbance properties on Au/ZnCo{sub 2}O{sub 4} enabled the superior CO preferential oxidation. Notably, electron paramagnetic resonance (EPR) and CO chemisorption (TPD-MS) results indicate that visible light could promote the adsorption and activation of both CO and O{sub 2} at Au/ZnCo{sub 2}O{sub 4} due to both the photo-response of Au nanoparticles and the photo-excitation of ZnCo{sub 2}O{sub 4} band gap under visible light irradiation. This study indicates that Au/ZnCo{sub 2}O{sub 4} may be highly desirable for a promising photo-assisted Au catalyst.

  4. High performance of visible-NIR broad spectral photocurrent application of monodisperse PbSe nanocubes decorated on rGO sheets

    Science.gov (United States)

    Ghorban Shiravizadeh, A.; Elahi, S. M.; Sebt, S. A.; Yousefi, Ramin

    2018-02-01

    In this work, the photoresponse performance of monodisperse PbSe nanocubes in the range of visible and near-infrared (NIR) (400-1500 nm) regions was enhanced by reduced graphene oxide (rGO). A simple cost-effective method is presented to synthesize monodisperse PbSe nanocubes (NCs) that are decorated on the rGO sheets. By the addition of PbSe/rGO nanocomposites with different rGO concentrations, pristine PbSe NCs were synthesized with the same method. Microscopy images showed that the size of NCs was smaller than the exciton Bohr radius (46 nm) of PbSe bulk. Therefore, the UV-Vis-IR spectroscopy result revealed that the PbSe/rGO samples had absorption peaks in the NIR region around 1650 nm and showed a blue shift compared to the absorption peak of the PbSe bulk. J-V measurements of the samples indicated that monodisperse PbSe/rGO nanocomposites had a higher resistance than the other samples under dark condition. On the other hand, the resistance of the monodisperse PbSe/rGO nanocomposites decreased under different light source illuminations while the resistance of the other samples was increased under illumination. Photodetector measurements indicated that the monodisperse morphology of the PbSe NCs enhanced the photoresponse speed and photocurrent intensity. In addition, responsivity (R) and detectivity (D*) of the samples were higher in the NIR region.

  5. Construction of fiber-shaped silver oxide/tantalum nitride p-n heterojunctions as highly efficient visible-light-driven photocatalysts.

    Science.gov (United States)

    Li, Shijie; Hu, Shiwei; Xu, Kaibing; Jiang, Wei; Liu, Yu; Leng, Zhe; Liu, Jianshe

    2017-10-15

    Constructing novel and efficient p-n heterojunction photocatalysts has stimulated great interest. Herein, we report the design and synthesis of fiber-shaped Ag 2 O/Ta 3 N 5 p-n heterojunctions as a kind of efficient photocatalysts. Ta 3 N 5 nanofibers were prepared by an electrospinning-calcination-nitridation method, and then the in-situ anchoring of Ag 2 O on their surfaces was realized by a facile deposition method. The resulting Ag 2 O/Ta 3 N 5 heterojunctions were comprised of porous Ta 3 N 5 nanofibers (diameter: ∼150nm) and Ag 2 O nanoparticles (size: ∼12nm). The photocatalytic activity of these heterojunctions were studied by decomposing rhodamine B (RhB) dye and tetracycline (TC) antibiotic under visible light (λ>400nm). In all the samples, the heterojunction with Ag 2 O/Ta 3 N 5 molar ratio of 0.2/1 displays the best activity. It is found that a synergistic effect contributes to the effective suppression of charges recombination between Ta 3 N 5 and Ag 2 O, leading to an enhanced photocatalytic activity with good stability. The photogenerated holes (h + ) and superoxide radicals (O 2 - ) play dominant roles in the photocatalytic process. These p-n heterojunctions will have great potential for environmental remediation because of the facile preparation process and exceptional photocatalytic activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Highly sensitive and simple liquid chromatography assay with ion-pairing extraction and visible detection for quantification of gold from nanoparticles.

    Science.gov (United States)

    Pallotta, Arnaud; Philippe, Valentin; Boudier, Ariane; Leroy, Pierre; Clarot, Igor

    2018-03-01

    A simple isocratic HPLC method using visible detection was developed and validated for the quantification of gold in nanoparticles (AuNP). After a first step of oxidation of nanoparticles, an ion-pair between tetrachloroaurate anion and the cationic dye Rhodamine B was formed and extracted from the aqueous media with the help of an organic solvent. The corresponding Rhodamine B was finally quantified by reversed phase liquid chromatography using a Nucleosil C18 (150mm × 4.6mm, 3µm) column and with a mobile phase containing acetonitrile and 0.1% trifluoroacetic acid aqueous solution (25/75, V/V) at 1.0mLmin -1. and at a wavelength of 555nm. The method was validated using methodology described by the International Conference on Harmonization and was shown to be specific, precise (RSD < 11%), accurate and linear in the range of 0.1 - 30.0µM with a lower limit of quantification (LLOQ) of 0.1µM. This method was in a first time applied to AuNP quality control after their synthesis. In a second time, the absence of gold leakage (either as AuNP or gold salt form) from nanostructured multilayered polyelectrolyte films under shear stress was assessed. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Facile synthesis of hierarchical Ag3PO4/TiO2 nanofiber heterostructures with highly enhanced visible light photocatalytic properties

    Science.gov (United States)

    Xie, Jinlei; Yang, Yefeng; He, Haiping; Cheng, Ding; Mao, Minmin; Jiang, Qinxu; Song, Lixin; Xiong, Jie

    2015-11-01

    Heterostructured semiconductor nanostructures have provoked great interest in the areas of energy, environment and catalysis. Herein, we report a novel hierarchical Ag3PO4/TiO2 heterostructure consisting of nearly spherical Ag3PO4 particles firmly coupled on the surface of TiO2 nanofibers (NFs). The construction of Ag3PO4/TiO2 heterostructure with tailored morphologies, compositions and optical properties was simply achieved via a facile and green synthetic strategy involving the electrospinning and solution-based processes. Owing to the synergetic effects of the components, the resulting hybrid heterostructures exhibited much improved visible light photocatalytic performance, which could degrade the RhB dye completely in 7.5 min. In addition, the coupling of Ag3PO4 particles with UV-light-sensitive TiO2 NFs enabled full utilization of solar energy and less consumption of noble metals, significantly appealing for their practical use in new energy sources and environmental issues. The developed synthetic strategy was considered to be applicable for the rational design and construction of other heterostructured catalysts.

  8. Spatial Co-Registration of Ultra-High Resolution Visible, Multispectral and Thermal Images Acquired with a Micro-UAV over Antarctic Moss Beds

    Directory of Open Access Journals (Sweden)

    Darren Turner

    2014-05-01

    Full Text Available In recent times, the use of Unmanned Aerial Vehicles (UAVs as tools for environmental remote sensing has become more commonplace. Compared to traditional airborne remote sensing, UAVs can provide finer spatial resolution data (up to 1 cm/pixel and higher temporal resolution data. For the purposes of vegetation monitoring, the use of multiple sensors such as near infrared and thermal infrared cameras are of benefit. Collecting data with multiple sensors, however, requires an accurate spatial co-registration of the various UAV image datasets. In this study, we used an Oktokopter UAV to investigate the physiological state of Antarctic moss ecosystems using three sensors: (i a visible camera (1 cm/pixel, (ii a 6 band multispectral camera (3 cm/pixel, and (iii a thermal infrared camera (10 cm/pixel. Imagery from each sensor was geo-referenced and mosaicked with a combination of commercially available software and our own algorithms based on the Scale Invariant Feature Transform (SIFT. The validation of the mosaic’s spatial co-registration revealed a mean root mean squared error (RMSE of 1.78 pixels. A thematic map of moss health, derived from the multispectral mosaic using a Modified Triangular Vegetation Index (MTVI2, and an indicative map of moss surface temperature were then combined to demonstrate sufficient accuracy of our co-registration methodology for UAV-based monitoring of Antarctic moss beds.

  9. BiOCl{sub x}Br{sub y}I{sub z} (x + y + z = 1) solid solutions with controllable band gap and highly enhanced visible light photocatalytic performances

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiuguo; Zhang, Yangyang; Li, Chunmei; Zhang, Zhifeng; Peng, Zheng; Si, Huayan; Zhang, Jianmin [School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043 (China); Li, Yanting, E-mail: yantingcn@stdu.edu.cn [School of Materials Science and Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043 (China); Hebei Provincial Key Laboratory of Traffic Engineering materials, Shijiazhuang Tiedao University, Shijiazhuang 050043 (China)

    2015-07-25

    Highlights: • BiOCl{sub x}Br{sub y}I{sub z} solid solutions were prepared by hydrolysis method. • Band gap of the solid solutions can be controllable by adjusting the molar ratio of halogen ions. • The samples show higher visible light photocatalytic activity than pure BiOX. • Orbital diversification of VB is beneficial to separating the holes and electrons effectively. • The mechanisms are discussed by active species trapping and band theory. - Abstract: A series of BiOCl{sub x}Br{sub y}I{sub z} solid solutions with controllable band gap and highly enhanced visible light photocatalytic performances were synthesized by a simple hydrolysis method. The samples were characterized by X-ray powder diffraction, UV–vis diffuse reflectance spectra, scanning electron microscope, high-resolution transmission electron microscopy and Brunauer–Emmett–Teller analysis. By adjusting the molar ratio of halogen ions, the band gap of BiOCl{sub x}Br{sub y}I{sub z} could be controllable to the suitable value for a photocatalytic reaction. Especially, BiOCl{sub x}Br{sub y}I{sub z} with a 1:1:2 molar ratio of Cl, Br to I showed the highest visible light photocatalytic activity for the degradation of methyl orange than individual BiOX systems. The degradation efficiency could reach over 90% within 60 min. The possible mechanism of photogenerated carrier transfer and higher photocatalytic activity was analyzed by active species trapping and energy band theory.

  10. Instrumental neutron activation analysis of 23 individual food articles from a high altitude region. Part 1. Determination of 14 essential minor and trace elements

    International Nuclear Information System (INIS)

    Waheed, S.; Zaidi, J.H.; Ahmad, S.; Saleem, M.

    2002-01-01

    Twenty-three individual food items commonly consumed in a high altitude region (Kashmir) have been investigated using instrumental neutron activation analysis. The concentration of Ca, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Se, Sn, and Zn is reported for these food articles. For quality assurance of our data, IAEA and NIST standard reference materials have also been studied. The dietary intake of these elements was calculated in accordance with the weekly food selection habits of the residents of this area. The dietary contribution of most of these elements was found to be in agreement to the RDA/ESadi levels. The purpose was to design a database of essential elements for this area and to study the adequacy levels of these elements in different dietary items. Fairly adequate intake of Ca, Co, Cr, Cu, Fe, Mg, Mn, Mo, Se, Sn, and Zn through these foodstuffs is reported, whereas, lower intakes through these items were found for Cl, K, and Na. (author)

  11. Highly efficient visible-light-induced photocatalytic activity of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chaiwichian, Saranyoo [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai50200 (Thailand); Inceesungvorn, Burapat [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Wetchakun, Khatcharin [Program of Physics, Faculty of Science, Ubon Ratchathani Rajabhat University, Ubon Ratchathani 34000 (Thailand); Phanichphant, Sukon [Materials Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Kangwansupamonkon, Wiyong [National Nanotechnology Center, Thailand Science Park, Phahonyotin Road, Klong 1, Klong Luang, Phathumthani 12120 (Thailand); Wetchakun, Natda, E-mail: natda_we@yahoo.com [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai50200 (Thailand)

    2014-06-01

    Highlights: • Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were obtained using hydrothermal method. • Physicochemical properties played a significant role on photocatalytic efficiency. • Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterogeneous structures were greatly enhanced for degradation of MB. • A tentative mechanism of charge transfer process in MB degradation was proposed. - Abstract: The Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts were synthesized by hydrothermal method. Physical properties of the heterojunction photocatalyst samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The XRD results indicated that BiVO{sub 4} retain monoclinic and tetragonal structures, while Bi{sub 2}WO{sub 6} presented as orthorhombic structure. The Brunauer, Emmett and Teller (BET) adsorption–desorption of nitrogen gas for specific surface area determination at the temperature of liquid nitrogen was performed on all samples. UV–vis diffuse reflectance spectra (UV–vis DRS) were used to identify the absorption range and band gap energy of the heterojunction photocatalysts. The photocatalytic performance of Bi{sub 2}WO{sub 6}/BiVO{sub 4} heterojunction photocatalysts was studied via the photodegradation of methylene blue (MB) under visible light irradiation. The results indicated that the heterojunction photocatalyst at 0.5:0.5 mole ratio of Bi{sub 2}WO{sub 6}:BiVO{sub 4} shows the highest photocatalytic activity.

  12. Synthesis of carbon-doped nanosheets m-BiVO{sub 4} with three-dimensional (3D) hierarchical structure by one-step hydrothermal method and evaluation of their high visible-light photocatalytic property

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Deqiang; Zong, Wenjuan [Chongqing University, Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-carbon and Green Buildings (China); Fan, Zihong [School of Environmental and Biological Engineering Chongqing Technology and Business University (China); Fang, Yue-Wen [East China Normal University, Key Laboratory of Polar Materials and Devices, Ministry of Education, Department of Electronic Engineering (China); Xiong, Shimin; Du, Mao; Wu, Tianhui; Ji, Fangying, E-mail: jfy@cqu.edu.cn; Xu, Xuan, E-mail: xuxuan@cqu.edu.cn [Chongqing University, Key Laboratory of Three Gorges Reservoir Region’s Eco-Environment Ministry of Education and National Centre for International Research of Low-carbon and Green Buildings (China)

    2017-04-15

    To achieve an efficient visible-light absorption and degradation of bismuth vanadate (BiVO{sub 4}), in this paper, a carbon-doped (C-doped) nanosheets monoclinic BiVO{sub 4} (m-BiVO{sub 4}), with thicknesses within 19.86 ± 8.48 nm, was synthesized using polyvinylpyrrolidone K-30 (PVP) as a template and l-carbonic as the carbon source by one-step hydrothermal synthesis method. This C-doped BiVO{sub 4} in three-dimensional (3D) hierarchical structure enjoys high visible-light photocatalytic property. The samples were characterized using x-ray diffraction, scanning electron microscope, Raman spectra, energy dispersive spectrometer, transmission electron microscope, x-ray photoelectron spectroscopy, UV–Vis diffused reflectance spectroscopy, specific surface area, electron spin resonance, and transient photocurrent response, photoluminescence spectra, and incident-photon-to-current conversion efficiency, respectively. What is more, we studied the C-doping effect on the band-gap energy of BiVO{sub 4} based on First-principles. X-ray diffraction analysis showed that all photocatalysts were in the same single monoclinic scheelite structure. According to the other characterization results, the element C was successfully doped in BiVO{sub 4}, resulting in the 3D hierarchical structure of C-doped BiVO{sub 4} (P-L-BiVO{sub 4}). We speculated that it could be the directional coalescence mechanism by which the l-cysteine promoted the two-dimensional growth and C-doping process of BiVO{sub 4}, thus leading to the formation of nanosheets which were then promoted into 3D self-assembly by PVP and the shortening of the band gap. Among all samples, P-L-BiVO{sub 4} can make the highest removal ratio of rhodamine B under visible-light irradiation. The stability of P-L-BiVO{sub 4} was verified by recycle experiments. It showed that P-L-BiVO{sub 4} had strong visible-light absorption behavior and high electron–hole separation efficiency and stability, making a significant

  13. In/visible Punctuation

    Science.gov (United States)

    Lennard, John

    2011-01-01

    This article offers two approaches to the question of "invisible punctuation," theoretical and critical. The first is a taxonomy of modes of punctuational invisibility, identifying "denial, repression, habituation, error" and "absence." Each is briefly discussed and some relations with technologies of reading are considered. The second considers…

  14. Making the Silence Visible

    Science.gov (United States)

    Keshavarz, Fatemeh

    2006-01-01

    This article discusses the vulnerability of U.S. professors of Islamic and Near Eastern studies, particularly if they are of Muslim origin. The author, a scholar of subjects related to literatures and cultures of the Muslim world, who is herself of Muslim origin, has found it more difficult in recent years to bring many topics to the classroom.…

  15. Fabrication and photocatalytic activity of high-efficiency visible-light-responsive photocatalyst ZnTe/TiO2 nanotube arrays

    International Nuclear Information System (INIS)

    Liu Yutang; Zhang Xilin; Liu Ronghua; Yang Renbin; Liu Chengbin; Cai Qingyun

    2011-01-01

    A new ZnTe modified TiO 2 nanotube (NT) array catalyst was prepared by pulse potential electrodeposition of ZnTe nanoparticles (NPs) onto TiO 2 NT arrays, and its application for photocatalytic degradation of anthracene-9-carboxylic acid (9-AnCOOH) was investigated. The even distribution of ZnTe NPs was well-proportionately grown on the top surface of the TiO 2 NT while without clogging the tube entrances. Compared with the unmodified TiO 2 NT, the ZnTe modified TiO 2 NT (ZnTe/TiO 2 NT) showed significantly enhanced photocatalytic activity towards 9-AnCOOH under simulated solar light. After 70 min of irradiation, 9-AnCOOH was degraded with the removal ratio of 45% on the bare TiO 2 NT, much lower than 80%, 90%, and 100% on the ZnTe/TiO 2 NT with the ZnTe NPs prepared under the pulsed 'on' potentials of -0.8, -1.0, and -2.0 V, respectively. The increased photodegradation efficiency mainly results from the improved photocurrent density as results of enhanced visible-light absorption and decreased hole-electron recombination due to the presence of narrow-band-gap p-type semiconductor ZnTe. -- Graphical abstract: Surface-view SEM images of ZnTe/TiO 2 NT prepared under -2.0 V, and the inset is the corresponding enlarged drawings. Display Omitted Research highlights: → A new method to deposit chalcogenides of transition metals on the TiO 2 nanotubes. → The even distribution of ZnTe nanoparticles was well-proportionedly grown onto TiO 2 NT arrays. → ZnTe/TiO 2 NT showed remarkably increased photocurrent density. → ZnTe/TiO 2 NT showed good photocatalytic performance. → The prepared new catalyst has a promising application in practical systems.

  16. Synthesis of surface molecular imprinted TiO{sub 2}/graphene photocatalyst and its highly efficient photocatalytic degradation of target pollutant under visible light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Cui, E-mail: laicui@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan (China); Wang, Man-Man [College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan (China); Zeng, Guang-Ming, E-mail: zgming@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan (China); Liu, Yun-Guo; Huang, Dan-Lian; Zhang, Chen; Wang, Rong-Zhong; Xu, Piao; Cheng, Min; Huang, Chao; Wu, Hai-Peng; Qin, Lei [College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, Hunan (China)

    2016-12-30

    Highlights: • The surface molecular imprinting technique was successfully combined with photocatalyst. • Molecularly imprinted photocatalyst exhibits recognition ability to the target molecules. • MIP-TiO{sub 2}/GR shows higher adsorption capacity and selectivity than NIP-TiO{sub 2}/GR. • The photocatalytic activity of MIP-TiO{sub 2}/GR is enhanced for target molecules. - Abstract: The molecular imprinted TiO{sub 2}/graphene photocatalyst (MIP-TiO{sub 2}/GR) was successfully prepared with bisphenol A (BPA) as the template molecule (target pollutant) and o-phenylenediamine (OPDA) as functional monomers by the surface molecular imprinting method. The combination between BPA and OPDA led to the formation of the precursor, and the subsequent polymerization of OPDA initiated by ultraviolet radiation can ensure the realization of MIP-TiO{sub 2}/GR. The samples were characterized by SEM, EDS, XRD, BET, UV–vis DRS and Zeta potential. In addition, adsorption capacities, adsorption selectivity and visible light photocatalytic performances of MIP-TiO{sub 2}/GR and non-imprinted TiO{sub 2}/graphene (NIP-TiO{sub 2}/GR) were evaluated. Moreover, the effects of pH and initial BPA concentration on removal efficiency of BPA were also investigated. The results showed that MIP-TiO{sub 2}/GR exhibited better adsorption capacity and adsorption selectivity towards the template molecule compared to NIP-TiO{sub 2}/GR due to the imprinted cavities on the surface of MIP-TiO{sub 2}/GR. Moreover, the photocatalytic activity of MIP-TiO{sub 2}/GR toward the target molecules was stronger than that of NIP-TiO{sub 2}/GR as a result of large adsorption capacity to target molecules and narrow band gap energy on MIP-TiO{sub 2}/GR. Therefore, modifying the photocatalyst by the surface molecular imprinting is a promising method to improve the molecule recognition and photocatalytic efficiency of photocatalyst for target pollutant.

  17. Revisiting visibility in the plane

    DEFF Research Database (Denmark)

    Wilkinson, Bryan Thomas

    Abstract We consider two closely related problems: computing the region visible from a point amid simple polygonal obstacles and computing the lower envelope of a set of disjoint segments. Visibility problems such as these were proposed and promptly solved in the late'80s and early'90s before...

  18. Tuning Cu dopant of Zn 0.5 Cd 0.5 S nanocrystals enables high-performance photocatalytic H 2 evolution from water splitting under visible-light irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Zongwei; Zhang, Bingkai; Zheng, Jiaxin; Yuan, Sheng; Zhuo, Zengqing; Meng, Xianguang; Chen, Zonghai; Amine, Khalil; Yang, Wanli; Wang, Lin. -Wang; Wang, Wei; Wang, Shufeng; Gong, Qihuang; Li, Jun; Liu, Fu. -Sheng; Pan, Feng

    2016-08-01

    Cu-doping into Zn1-xCdxS can greatly enhance the photocatalytic H2 evolution from water splitting under visible-light irradiation. However, it is still controversial for how the Cu-dopant improves this performance. Here, we report that appropriate Cu-doped Zn0.5Cd0.5S nanocrystals reach 21.4 mmol/h/g of H2 evolution rate without cocatalyst in the visible-light region, which is also 2.8 times as high as that of the undoped counterpart, and the corresponding apparent quantum efficiency is 18.8% at 428 nm. It is firstly confirmed that the Cu2+ changes into Cu+ after being doped by soft X-ray absorption spectroscopy (sXAS). We theoretically propose that the transformation of 2Cu2+ to 2Cu+ results in one adjacent S2- vacancy (VS) in host during the doping process, while the Cu+-dopant and VS attract the photoexcited holes and electrons, respectively. Accordingly, the photocatalytic activity is improved due to the enhanced separation of photoexcited carriers accompanied with the enhanced light absorption resulting from the Cu+-dopant and 2Cu+/VS complex as possible active site for photocatalytic H2 evolution.

  19. Sol-Gel-Hydrothermal Synthesis of the Heterostructured TiO2/N-Bi2WO6 Composite with High-Visible-Light- and Ultraviolet-Light-Induced Photocatalytic Performances

    Directory of Open Access Journals (Sweden)

    Jiang Zhang

    2012-01-01

    Full Text Available The heterostructured TiO2/N-Bi2WO6 composites were prepared by a facile sol-gel-hydrothermal method. The phase structures, morphologies, and optical properties of the samples were characterized by using X-ray powder diffraction (XRD, scanning electron microscopy (SEM, high-resolution transmission electron microscopy (HRTEM, energy dispersive spectroscopy (EDS, and UV-vis diffuse reflectance spectroscopy. The photocatalytic activities for rhodamine B of the as-prepared products were measured under visible and ultraviolet light irradiation at room temperature. The TiO2/N-Bi2WO6 composites exhibited much higher photocatalytic performances than TiO2 as well as Bi2WO6. The enhancement in the visible light photocatalytic performance of the TiO2/N-Bi2WO6 composites could be attributed to the effective electron-hole separations at the interfaces of the two semiconductors, which facilitate the transfer of the photoinduced carriers.

  20. Red Card Article 17?

    OpenAIRE

    Molenaar, Dick

    2012-01-01

    textabstractIn this article, the authors assess the current position regarding the debate over article 17 of the OECD Model (2010) and whether or not the provision should be amended, or even be considered for removal from the OECD Model.

  1. On characterizing terrain visibility graphs

    Directory of Open Access Journals (Sweden)

    William Evans

    2015-06-01

    Full Text Available A terrain is an $x$-monotone polygonal line in the $xy$-plane. Two vertices of a terrain are mutually visible if and only if there is no terrain vertex on or above the open line segment connecting them. A graph whose vertices represent terrain vertices and whose edges represent mutually visible pairs of terrain vertices is called a terrain visibility graph. We would like to find properties that are both necessary and sufficient for a graph to be a terrain visibility graph; that is, we would like to characterize terrain visibility graphs.Abello et al. [Discrete and Computational Geometry, 14(3:331--358, 1995] showed that all terrain visibility graphs are “persistent”. They showed that the visibility information of a terrain point set implies some ordering requirements on the slopes of the lines connecting pairs of points in any realization, and as a step towards showing sufficiency, they proved that for any persistent graph $M$ there is a total order on the slopes of the (pseudo lines in a generalized configuration of points whose visibility graph is $M$.We give a much simpler proof of this result by establishing an orientation to every triple of vertices, reflecting some slope ordering requirements that are consistent with $M$ being the visibility graph, and prove that these requirements form a partial order. We give a faster algorithm to construct a total order on the slopes. Our approach attempts to clarify the implications of the graph theoretic properties on the ordering of the slopes, and may be interpreted as defining properties on an underlying oriented matroid that we show is a restricted type of $3$-signotope.

  2. Infrared and visible fusion face recognition based on NSCT domain

    Science.gov (United States)

    Xie, Zhihua; Zhang, Shuai; Liu, Guodong; Xiong, Jinquan

    2018-01-01

    Visible face recognition systems, being vulnerable to illumination, expression, and pose, can not achieve robust performance in unconstrained situations. Meanwhile, near infrared face images, being light- independent, can avoid or limit the drawbacks of face recognition in visible light, but its main challenges are low resolution and signal noise ratio (SNR). Therefore, near infrared and visible fusion face recognition has become an important direction in the field of unconstrained face recognition research. In this paper, a novel fusion algorithm in non-subsampled contourlet transform (NSCT) domain is proposed for Infrared and visible face fusion recognition. Firstly, NSCT is used respectively to process the infrared and visible face images, which exploits the image information at multiple scales, orientations, and frequency bands. Then, to exploit the effective discriminant feature and balance the power of high-low frequency band of NSCT coefficients, the local Gabor binary pattern (LGBP) and Local Binary Pattern (LBP) are applied respectively in different frequency parts to obtain the robust representation of infrared and visible face images. Finally, the score-level fusion is used to fuse the all the features for final classification. The visible and near infrared face recognition is tested on HITSZ Lab2 visible and near infrared face database. Experiments results show that the proposed method extracts the complementary features of near-infrared and visible-light images and improves the robustness of unconstrained face recognition.

  3. Development and Validation of High Performance Thin-Layer Chromatographic Method for Determination of α-Mangostin in Fruit Pericarp of Mangosteen Plant (Garcinia mangostana L. using Ultraviolet – Visible Detection

    Directory of Open Access Journals (Sweden)

    Himanshu Misra

    2009-10-01

    Full Text Available A simple, fast and precise quantitative high performance thin-layer chromatographic method has been developed for quantitative estimation of α-mangostin in fruit pericarp of Garcinia mangostana L. (Hypericaceae. Best solvent for extraction of a-mangostin optimized after screening with five solvents under same conditions using hot solid-liquid extraction through soxhlet apparatus. Methanol and chloroform gave highest and second highest recovery of a-mangostin, respectively. Plates were developed in chloroform-methanol in the ratio of 27-3 (v/v. Post-chromatographic derivatization performed using anisaldehyde-sulphuric acid reagent and scanned at 382 nm in ultraviolet-visible mode. The developed method was found to be linear in the range 1.0 to 5.0 mg spot-1, limits of detection and quantitation were 150 and 450 ng spot-1. The developed method was validated in terms of system suitability, specificity and robustness.

  4. Visible light reduces C. elegans longevity.

    Science.gov (United States)

    De Magalhaes Filho, C Daniel; Henriquez, Brian; Seah, Nicole E; Evans, Ronald M; Lapierre, Louis R; Dillin, Andrew

    2018-03-02

    The transparent nematode Caenorhabditis elegans can sense UV and blue-violet light to alter behavior. Because high-dose UV and blue-violet light are not a common feature outside of the laboratory setting, we asked what role, if any, could low-intensity visible light play in C. elegans physiology and longevity. Here, we show that C. elegans lifespan is inversely correlated to the time worms were exposed to visible light. While circadian control, lite-1 and tax-2 do not contribute to the lifespan reduction, we demonstrate that visible light creates photooxidative stress along with a general unfolded-protein response that decreases the lifespan. Finally, we find that long-lived mutants are more resistant to light stress, as well as wild-type worms supplemented pharmacologically with antioxidants. This study reveals that transparent nematodes are sensitive to visible light radiation and highlights the need to standardize methods for controlling the unrecognized biased effect of light during lifespan studies in laboratory conditions.

  5. Incremental Visualizer for Visible Objects

    DEFF Research Database (Denmark)

    Bukauskas, Linas; Bøhlen, Michael Hanspeter

    This paper discusses the integration of database back-end and visualizer front-end into a one tightly coupled system. The main aim which we achieve is to reduce the data pipeline from database to visualization by using incremental data extraction of visible objects in a fly-through scenarios. We...... also argue that passing only relevant data from the database will substantially reduce the overall load of the visualization system. We propose the system Incremental Visualizer for Visible Objects (IVVO) which considers visible objects and enables incremental visualization along the observer movement...... path. IVVO is the novel solution which allows data to be visualized and loaded on the fly from the database and which regards visibilities of objects. We run a set of experiments to convince that IVVO is feasible in terms of I/O operations and CPU load. We consider the example of data which uses...

  6. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... This article is devoted to the modeling of sound absorption .... two-channel sound level meter, 6 - white noise generator. ... sound pressure was perceived by two microphones 3, 4, connected with the sound level meter. 5.

  7. Research Article Special Issue

    African Journals Online (AJOL)

    2016-07-16

    Jul 16, 2016 ... counterfeiting of currency and monetary instruments, money ... the term economic corruption which is frequently used by researchers in .... mentioned in the provisions and legislator also added fraud to this list under Article.

  8. Aaron Journal article datasets

    Data.gov (United States)

    U.S. Environmental Protection Agency — All figures used in the journal article are in netCDF format. This dataset is associated with the following publication: Sims, A., K. Alapaty , and S. Raman....

  9. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-02-01

    Feb 1, 2018 ... The main goal of this article is to analyze methodological issues in .... methodology and theory and historiology (theory of historic process) whose goal is to .... internal branches of sociology and interdisciplinary links of ...

  10. Research Article Special Issue

    African Journals Online (AJOL)

    2017-02-15

    Feb 15, 2017 ... The article also discusses the process and results of computer modeling, an error that arises ..... Prediction positioning quality .... topocentric and angular coordinates of the selected navigational satellites can determine if this.

  11. Research Article Special Issue

    African Journals Online (AJOL)

    2017-02-15

    Feb 15, 2017 ... Research Article. Special Issue ... In myriad studies implemented, the quality of life has been defined in different ways among which the .... service and trading users in living area. ... market, bakery, barber shop, restaurant, etc.

  12. Research Article Special Issue

    African Journals Online (AJOL)

    2017-02-15

    Feb 15, 2017 ... P. V. Vasiliev, V. M. Mikhelev, V. V. Muromtcev and D. S. Batischev ... Annotation This article describes algorithm for solving ultimate pit limit ... It is simplified version of the production-scheduling problem that details the.

  13. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... In this article, to improve the performance of metal cylindrical mesh shells used ... Finite element models are designed taking into account ... IFI type unit is used to increase the bearing capacity and reduce the deformation of.

  14. Research Article Special Issue

    African Journals Online (AJOL)

    2017-11-24

    Nov 24, 2017 ... The article is devoted to the experimental studies of the effect of elastic operating elements of a ... Keywords: multicomponent granular mixture, mixer with elastic ... physico-mechanical properties and design features, without ...

  15. Scientific Journal Articles

    Science.gov (United States)

    These are abstracts of peer-reviewed articles, authored by Office of Children's Health Protection staff. They cover topics including risk assessment for early life stages, inhalation dosimetry, and manganese in drinking water.

  16. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-03-07

    Mar 7, 2018 ... where the operations of all sorts of searches and sorting are the most complex ones. Existing ... The object of this article development and research is an associative ..... ARPN Journal of Engineering and Applied Sciences.

  17. Visible neutrino decay at DUNE

    Energy Technology Data Exchange (ETDEWEB)

    Coloma, Pilar [Fermilab; Peres, Orlando G. [ICTP, Trieste

    2017-05-09

    If the heaviest neutrino mass eigenstate is unstable, its decay modes could include lighter neutrino eigenstates. In this case part of the decay products could be visible, as they would interact at neutrino detectors via mixing. At neutrino oscillation experiments, a characteristic signature of such \\emph{visible neutrino decay} would be an apparent excess of events at low energies. We focus on a simple phenomenological model in which the heaviest neutrino decays as $\

  18. Reactive removal of 2-chloroethyl ethyl sulfide vapors under visible light irradiation by cerium oxide modified highly porous zirconium (hydr) oxide

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Joshua K.; Arcibar-Orozco, Javier A.; Bandosz, Teresa J., E-mail: tbandosz@ccny.cuny.edu

    2016-12-30

    Highlights: • Microporous zirconium-cerium (hydr) oxides were synthetized. • Ce presence narrowed the band gap of the materials. • The samples showed a high efficiency for removal of CEES vapors. • 1,2-Bis (ethyl thio) ethane and ethyl vinyl sulfide were the main reaction products. • 5% (Ce/Zr mol) addition of cerium oxide results in the best performing material. - Abstract: Highly porous cerium oxide modified Zr(OH){sub 4} samples were synthesized using a simple one stage urea precipitation method. The amorphicity level of zirconium hydroxide did not change upon addition of cerium oxide particles. A unique aspect of the cerium oxide-modified materials is the presence of both the oxide (CeO{sub 2}) and hydroxide (Zr(OH){sub 4}) phases resulting in a unique microporous structure of the final material. Extensive characterization using various chemical and physical methods revealed significant differences in the surface features. All synthesized materials were microporous and small additions of cerium oxide affected the surface chemistry. These samples were found as effective catalysts for a decontamination of mustard gas surrogate, 2-chloroethyl ethyl sulfide (CEES). Cerium oxide addition significantly decreased the band gap of zirconium hydroxide. Ethyl vinyl sulfide and 1,2-bis (Ethyl thio) ethane were identified as surface reaction products.

  19. High resolution scanning electron microscopy of rabbit corneal endothelium to show effects of UV-visible irradiation in the presence of chlorpromazine

    International Nuclear Information System (INIS)

    Lea, P.J.; Hollenberg, M.J.; Menon, I.A.; Temkin, R.J.; Persad, S.D.; Basu, P.K.

    1989-01-01

    The ultrastructure of rabbit cornea endothelial cells was examined by scanning electron microscopy (SEM) in freeze-cleaved corneas using a Hitachi S-570 scanning electron microscope in the high resolution mode (HRSEM). In order to study phototoxic effects in vitro, rabbit corneas (experimental) were cultured as organ culture in the presence of 5 micrograms/ml chlorpromazine (CPZ) and irradiated. For comparison, control 1 corneas were not irradiated but incubated in the dark without CPZ in the medium; control 2 corneas were also kept in the dark but in the presence of CPZ; control 3 corneas were irradiated with no CPZ in the medium. Cellular damage was not seen in the three types of control corneas, but in the experimental corneas the endothelial cells showed extensive disruption of the cell membrane and some deterioration of the intracellular components. Our study confirmed that HRSEM is a satisfactory new technique for visualizing damage of the intracellular organelles of corneal endothelium

  20. High resolution scanning electron microscopy of rabbit corneal endothelium to show effects of UV-visible irradiation in the presence of chlorpromazine

    Energy Technology Data Exchange (ETDEWEB)

    Lea, P.J.; Hollenberg, M.J.; Menon, I.A.; Temkin, R.J.; Persad, S.D.; Basu, P.K. (Univ. of Toronto, Ontario (Canada))

    1989-01-01

    The ultrastructure of rabbit cornea endothelial cells was examined by scanning electron microscopy (SEM) in freeze-cleaved corneas using a Hitachi S-570 scanning electron microscope in the high resolution mode (HRSEM). In order to study phototoxic effects in vitro, rabbit corneas (experimental) were cultured as organ culture in the presence of 5 micrograms/ml chlorpromazine (CPZ) and irradiated. For comparison, control 1 corneas were not irradiated but incubated in the dark without CPZ in the medium; control 2 corneas were also kept in the dark but in the presence of CPZ; control 3 corneas were irradiated with no CPZ in the medium. Cellular damage was not seen in the three types of control corneas, but in the experimental corneas the endothelial cells showed extensive disruption of the cell membrane and some deterioration of the intracellular components. Our study confirmed that HRSEM is a satisfactory new technique for visualizing damage of the intracellular organelles of corneal endothelium.

  1. Effects of ultraviolet radiation, visible light, and infrared radiation on erythema and pigmentation: a review.

    Science.gov (United States)

    Sklar, Lindsay R; Almutawa, Fahad; Lim, Henry W; Hamzavi, Iltefat

    2013-01-01

    The effects of ultraviolet radiation, visible light, and infrared radiation on cutaneous erythema, immediate pigment darkening, persistent pigment darkening, and delayed tanning are affected by a variety of factors. Some of these factors include the depth of cutaneous penetration of the specific wavelength, the individual skin type, and the absorption spectra of the different chromophores in the skin. UVB is an effective spectrum to induce erythema, which is followed by delayed tanning. UVA induces immediate pigment darkening, persistent pigment darkening, and delayed tanning. At high doses, UVA (primarily UVA2) can also induce erythema in individuals with skin types I-II. Visible light has been shown to induce erythema and a tanning response in dark skin, but not in fair skinned individuals. Infrared radiation produces erythema, which is probably a thermal effect. In this article we reviewed the available literature on the effects of ultraviolet radiation, visible light, and infrared radiation on the skin in regards to erythema and pigmentation. Much remains to be learned on the cutaneous effects of visible light and infrared radiation.

  2. NaYF4:Er,Yb/Bi2MoO6 core/shell nanocomposite: A highly efficient visible-light-driven photocatalyst utilizing upconversion

    International Nuclear Information System (INIS)

    Sun, Yuanyuan; Wang, Wenzhong; Sun, Songmei; Zhang, Ling

    2014-01-01

    Highlights: • Design and synthesis of NaYF 4 :Er,Yb/Bi 2 MoO 6 based on upconversion. • NaYF 4 :Er,Yb/Bi 2 MoO 6 nanocomposite was prepared for the first time. • Core–shell structure benefits the properties. • Upconversion contributed to the enhanced photocatalytic activity. • Helps to understand the functionality of new type photocatalysts. - Abstract: NaYF 4 :Er,Yb/Bi 2 MoO 6 core/shell nanocomposite was designed and prepared for the first time based on upconversion. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDS) and diffuse reflectance spectra (DRS). The results revealed that the as-synthesized NaYF 4 :Er,Yb/Bi 2 MoO 6 consisted of spheres with a core diameter of about 26 nm and a shell diameter of around 6 nm. The core was upconversion illuminant NaYF 4 :Er,Yb and the shell was Bi 2 MoO 6 around the core, which was confirmed by EDS. The NaYF 4 :Er,Yb/Bi 2 MoO 6 exhibited higher photocatalytic activity for the photodecomposition of Rhodamine B (RhB) under the irradiation of Xe lamp and green light emitting diode (g-LED). The mechanism of the high photocatalytic activity was discussed by photoluminescence spectra (PL), which is mainly attributed to upconversion of NaYF 4 :Er,Yb in the NaYF 4 :Er,Yb/Bi 2 MoO 6 nanocomposite and the core–shell structure

  3. Recompressed exfoliated graphite articles

    Science.gov (United States)

    Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

    2013-08-06

    This invention provides an electrically conductive, less anisotropic, recompressed exfoliated graphite article comprising a mixture of (a) expanded or exfoliated graphite flakes; and (b) particles of non-expandable graphite or carbon, wherein the non-expandable graphite or carbon particles are in the amount of between about 3% and about 70% by weight based on the total weight of the particles and the expanded graphite flakes combined; wherein the mixture is compressed to form the article having an apparent bulk density of from about 0.1 g/cm.sup.3 to about 2.0 g/cm.sup.3. The article exhibits a thickness-direction conductivity typically greater than 50 S/cm, more typically greater than 100 S/cm, and most typically greater than 200 S/cm. The article, when used in a thin foil or sheet form, can be a useful component in a sheet molding compound plate used as a fuel cell separator or flow field plate. The article may also be used as a current collector for a battery, supercapacitor, or any other electrochemical cell.

  4. The highly enhanced visible light photocatalytic degradation of gaseous o-dichlorobenzene through fabricating like-flowers BiPO{sub 4}/BiOBr p-n heterojunction composites

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Xuejun [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Dong, Yuying, E-mail: dongy@dlnu.edu.cn [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Zhang, Xiaodong, E-mail: fatzhxd@126.com [Environment and Low-Carbon Research Center, School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai, 200093 (China); Cui, Yubo; Ou, Xiaoxia [Department of Environmental Science and Technology, Dalian Nationalities University, Dalian, 116600 (China); Qi, Xiaohui [College of Life Science, Dalian Nationalities University, Dalian, 116600 (China)

    2017-01-01

    Highlights: • Like-flowers BiPO{sub 4}/BiOBr was fabricated by mixing in solvent method. • o-Dichlorobenzene removal efficiency was 53.6% using BiPO{sub 4}/BiOBr. • The p–n junction improved o-dichlorobenzene degradation activity. - Abstract: In this paper, in order to enhance photo-induced electron-hole pairs separation of BiOBr, flowers-like BiPO{sub 4}/BiOBr p-n heterojunction composites was fabricated by a mixing in solvent method. The as-prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), UV–vis absorption spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), and N{sub 2} adsorption-desorption. Meanwhile, their photocatalytic properties were investigated by the degradation of gaseous o-dichlorobenzene under visible light irradiation. Due to its strong adsorption capacity and the formation of p-n heterojunction, compared with BiPO{sub 4} and BiOBr, the BiPO{sub 4}/BiOBr composites showed higher photocatalytic activity in the degradation of gaseous o-DCB under visible light. Among them, 2% BiPO{sub 4}/BiOBr showed the maximum value of the activity, whose degradation rate was about 2.6 times as great as the pure BiOBr. Furthermore, the OH· was confirmed the main active species during the photocatalytic process by the trapping experiments. The outstanding performance indicated that the photocatalysts could be applied to air purification for chlorinated volatile organic compound.

  5. Some remarks about the article by B.A. Troubnikoff and A.E. Bajanova on losses by magnetic radiation of plasmas at high temperature; Quelques remarques sur l'article de B.A. Troubnikoff et A.E. Bajanova sur les pertes par rayonnement magnetique des plasmas a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Lepechinski, D. Ingenieur Chef contractuel au C. N. E. T.

    1960-07-01

    In this note, the author discusses the content of an article published by other authors. He first recalls and comments how these authors show that if magnetic radiation absorption of electrons in a plasma at high temperature is not taken into account, only the DT reaction provides an energy greater than that lost by the magnetic radiation under some condition. In the next part, he comments how the authors addressed the case for which magnetic radiation absorption is taken into account. In the third part, the author comments some calculations present in the published article. He finally states that curves produced in the article are rather pessimistic and overstate the transparency coefficient by a factor close to 2. He suggests other calculation approaches.

  6. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooher, G.I.

    1979-01-01

    A neutron absorbing article, in flat plate form and suitable for use in a storage rack for spent fuel, includes boron carbide particles, diluent particles and a solid, irreversibly cured phenolic polymer cured to a continuous matrix binding the boron carbide and diluent particles. The total conent of boron carbide and diluent particles is a major proportion of the article and the content of cured phenolic polymer present is a minor proportion. By regulation of the ratio of boron carbide particles to diluent particles, normally within the range of 1:9 and 9:1 and preferably within the range of 1:5 to 5:1, the neutron absorbing activity of the product may be controlled, which facilitates the manufacture of articles of particular absorbing activities best suitable for specific applications

  7. Visibility and surveillance regime in the age of Digital Identity

    Directory of Open Access Journals (Sweden)

    María Alejandra López Gabrielidis

    2015-12-01

    Full Text Available This article addresses the link between the hypervisibility regime in which the contemporary subject is immersed in and the new forms of surveillance. Based on an analysis of the work of Hito Steyerl How Not to be Seen: A Fucking Didactic Educational .MOV File (2013 we explore the changes suffered by the traditional form of surveillance with a special highlight on the current features of the cyber-surveillance device. The 21st century is witnessing a socio-technical phenomenon which transforms the subject into an image-data, as a result of what Paul Virilio calls the industrialization and proliferation of “visual machines” (photographic cameras, microscopes, telescopes, drones, the social online habits which tend to self-capture and self-diffusion, and the processes of datification. Nowadays, the subject assumes an active role in the surveillance mechanisms and, hence, is partly responsible of the control that is practiced over him. In this video, Hito Steyerl teaches us about camouflage techniques, confusion and low resolution uses, in order to be less visible before the eyes of the power. However, the excess of visibility and exposure of the subject seems to be a highly difficult situation to counteract in the technical conditions that we live in. As we propose in the last section of the article, in order to solve the surveillance problems in the digital age it is necessary to redefine the concept of privacy starting from the concept of digital identity, with all its implications. Consequently, we must lead the way into new forms of legal authority over data.

  8. W18O49 nanorods decorated with Ag/AgCl nanoparticles as highly-sensitive gas-sensing material and visible-light-driven photocatalyst

    International Nuclear Information System (INIS)

    Sun Shibin; Chang Xueting; Dong Lihua; Zhang Yidong; Li Zhenjiang; Qiu Yanyan

    2011-01-01

    A novel gas-sensing material and photocatalyst was successfully obtained by decorating Ag/AgCl nanoparticles on the W 18 O 49 nanorods through a clean photochemical route. The as-prepared samples were characterized using combined techniques of X-ray diffractometry, electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas-sensing measurements indicate that the Ag/AgCl/W 18 O 49 NRs sensors exhibit superior reducing gas-sensing properties to those of bare W 18 O 49 NRs, and they are highly selective and sensitive to NH 3 , acetone, and H 2 S with short response and recovery times. The Ag/AgCl/W 18 O 49 NRs photocatlysts also possess higher photocatalytic performance than bare W 18 O 49 NRs for degradation of methyl orange under simulated sunlight irradiation. Possible mechanisms concerning the enhancement of gas-sensing and photocatalytic activities of the Ag/AgCl/W 18 O 49 NRs composite were proposed. - Graphical Abstract: The Ag/AgCl nanoparticles adhered well to the W 18 O 49 nanorod. The Ag could act as transfer center of the photoexcited carriers, prohibiting their recombinations in both W 18 O 49 and AgCl. Highlights: → Ag/AgCl/W 18 O 49 NRs were successfully obtained via a clean photochemical route. → The Ag/AgCl nanoparticles decorated on the W 18 O 49 NRs possessed cladding structure. → The Ag/AgCl/W 18 O 49 NRs exhibited excellent gas-sensing and photocatalytic properties.

  9. Neutron absorbing article

    International Nuclear Information System (INIS)

    Naum, R.G.; Owens, D.P.; Dooker, G.I.

    1981-01-01

    A neutron-absorbing article suitable for use in spent fuel racks is described. It comprises boron carbide particles, diluent particles, and a phenolic polymer cured to a continuous matrix. The diluent may be silicon carbide, graphite, amorphous carbon, alumina, or silica. The combined boron carbide-diluent phase contains no more than 2 percent B 2 O 3 , and the neutron-absorbing article contains from 20 to 40 percent phenol resin. The ratio of boron carbide to diluent particles is in the range 1:9 to 9:1

  10. Simulating the z= 3.35 HI 21-cm Visibility Signal for the Ooty Wide ...

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  11. Visible tunable source

    International Nuclear Information System (INIS)

    1987-10-01

    We planned four tasks for the second phase of this project; these are: study the effect of different grating materials; study the effect of different grating shapes; study the effect of anisotropic conductivity, and optimize the resonator configuration. Because the measurement techniques involved in the first two tasks are similar, the studies on different grating materials and shapes are discussed together. We are conducting two more experiments which were not originally planned. An experiment with a high current pulsed e-beam generator is presented and a measurement of radiation as a function of beam thickness is reported

  12. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-02-01

    Feb 1, 2018 ... the Russian philosophical and sociological thought. The thoughts of the Russian scientist ... Research Article. Special Issue. Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International License. Libraries Resource Directory. We are ...

  13. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... Research Article. Special Issue. Journal of Fundamental and Applied Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0. International License. ... innovation is defined as: accepting ideas or behaviors in the organization that are novel and unfamiliar. Innovation can be in form ...

  14. Research Article Special Issue

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    Mar 7, 2018 ... This study is a review article designed to explore and explain the role of social ... Sciences is licensed under a Creative Commons Attribution-NonCommercial 4.0 ... Iranmedex, Magiran, Irandoc and MedLib, and four international ... as follows: Hard, severe and distorted thinking patterns (thoughts) 2.

  15. Research Article Special Issue

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    pc

    2017-10-17

    Oct 17, 2017 ... Perak, Malaysia was observed under ral waste in powder and xtract generated optimum produce highest length of fectively improved shoot ed faster effect on C. ed positive result for the shed light on how the Z. C. nutans. This study ld application. pagation; Zea mays stem. Research Article. Special Issue ...

  16. Research Article Special Issue

    African Journals Online (AJOL)

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    24 Ноя 2017 ... article includes the study of main characteristics of the concept "Моң" .... boundaries, is used to determine the media picture of the world of the speakers of Tatar ..... to the movies that often colorful, musical and dramatic televised) were ... aspects of intercultural communication theory, cultural studies, and ...

  17. Research Article Special Issue

    African Journals Online (AJOL)

    2017-02-15

    Feb 15, 2017 ... various geographical, economic, and social problems with the protection of the environment, and. Fragmentation and chaos rules, are: lack of adopting an integrated ... Keywords: Air Pollution, Legal System, International Law, Legal .... According to Article 12, construction of new factories and workshops ...

  18. Research Article Special Issue

    African Journals Online (AJOL)

    2017-02-15

    Feb 15, 2017 ... he achieves in innocence or guilt of the accused. ... exertion of influence by the prosecutor over the interrogator in a variety of ways ..... for decision-making and Article 75 onwards in French Code of Criminal Procedure gives.

  19. Research Article Special Issue

    African Journals Online (AJOL)

    2018-01-15

    Jan 15, 2018 ... Journal of Fundamental and Applied Scienc. ISSN 1112-9867 ... (0.9623, 0.3857) and (0.9975, ity, temperature, CO, UVB and. 10 concentration. In by using ANN or Fit model. Research Article. Special Issue .... The EM algorithm is a simple computational implementation to find the posterior mode. Fig.

  20. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-10-17

    Oct 17, 2017 ... In simple chronology, it is always true to say that better fluency .... Thus, in this research, GPL is used as the back-end software from the .... However, to present the quantitative measurement would be more .... Article title.

  1. Research Article Special Issue

    African Journals Online (AJOL)

    2017-08-08

    Aug 8, 2017 ... Research Article ... drying rate of the fluid materials also have a great influence on the quality of films. ... film's thickness versus spin speeds with speeds, th. 2. 4. 6. 8. 1500 ... where t is thickness and ω is angular velocity [19].

  2. 66 ORIGINAL ARTICLE

    African Journals Online (AJOL)

    boaz

    ORIGINAL ARTICLE. AFRICAN JOURNAL OF CLINICAL AND EXPERIMENTAL MICROBIOLOGY JAN 2016 ISBN 1595-689X VOL 17 No.1 ..... WOMEN. Social characteristics. No. examined (n = 310). No. positive. (n=30) (%). Education. Illiterate. Primary. Secondary. Tertiary. Occupation. Civil servant. House wife. Students.

  3. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-05-01

    May 1, 2018 ... This article proposed to develop problem-oriented system of decision support based on artifi- ... use hard-to-recover oil reserves and gas. The main .... of a drilling rig when organizing a system for supplying drilling spare parts.

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    2018-03-07

    Mar 7, 2018 ... ethical issues behind the retrieval of organs (commitment to ... The article reviews the practices of European countries and attitude of the EU citizens to the .... knowledge that the purchase and sale of donor organs is prohibited ...

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    African Journals Online (AJOL)

    pc

    2017-10-05

    Oct 5, 2017 ... Journal of Fundamental and Applied Sciences. ISSN 1112-9867. Available online at http://www.jfas.info. Research Article. Special Issue .... of use. Three critical success factors of e-learning (instructor characteristics, student characteristics .... Total of 95 questionnaires were used for further data analysis.

  6. Response to Trachtman's Article

    Science.gov (United States)

    Bardon, Jack I.

    1985-01-01

    This response to Trachtman's article (TM 510 399) argues that the Trachtman paper is inappropriate due to the time elapsed since the original Bardon proposal. The author acknowledges the difference in perspective between Trachtman and himself. He expresses the hope that discussion concerning this aspect of school psychology politics may be ended.…

  7. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... information educational space, are considered in the article. ... The analysis of the behavior of such systems "far from equilibrium" found that ... development and qualitative changes of the student's personality. ..... processing and testing the source codes of programs is similar to loading the source codes of.

  8. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... FEDERAL UNIVERSITY (FROM EMOTIONAL EDUCATION TO GLOBAL. THINKING ... ANNOTATION. The article highlights the topical issues of human education of the future humanistic- ... conditions (continuous self-education, updating and integration of educational resources on the basis of the ...

  9. Research Article Special Issue

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    2016-05-15

    May 15, 2016 ... AND CIVIL ENGINEERING (CASE STUDY: AMIRIYEH REGION OF SHAHRIAR ... Keywords: suburbanization; urban economics; urban development; AHP ... Analytical Network Process method was used to achieve the effect of ... Harstad, 2014 in an article titled, "imitation or innovation and Cooperation.

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    Aug 8, 2017 ... dak Campus, 21300 Kuala Terengganu, Terengganu, Malaysia ... performance of an athlete as opposed to views or self-report by the athlete, ... reliably does out the same score to people or articles with equivalent values, the instrument is ... sepak takraw youth athlete team (Tunku Mahkota Ismail Sport ...

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    2016-06-05

    Jun 5, 2016 ... because Amir al- Mu'minin's(peace be upon him) name is related to human perfection and. Journal of Fundamental and Applied Sciences. ISSN 1112-9867. Available online at http://www.jfas.info. Research Article. Special Issue. Journal of Fundamental and Applied Sciences is licensed under a Creative ...

  12. Visible Light Communication: An Emerging Area in Wireless

    Indian Academy of Sciences (India)

    A. Chockalingam

    infrared to ultraviolet. • includes visible light wavelengths (380 to 780 nm). Concluding remarks. NH ... low power, high data rate systems in satellites, portable devices, etc. .... improve spectral efficiency and performance. • Issues. • channel ...

  13. Visible-to-visible four-photon ultrahigh resolution microscopic imaging with 730-nm diode laser excited nanocrystals.

    Science.gov (United States)

    Wang, Baoju; Zhan, Qiuqiang; Zhao, Yuxiang; Wu, Ruitao; Liu, Jing; He, Sailing

    2016-01-25

    Further development of multiphoton microscopic imaging is confronted with a number of limitations, including high-cost, high complexity and relatively low spatial resolution due to the long excitation wavelength. To overcome these problems, for the first time, we propose visible-to-visible four-photon ultrahigh resolution microscopic imaging by using a common cost-effective 730-nm laser diode to excite the prepared Nd(3+)-sensitized upconversion nanoparticles (Nd(3+)-UCNPs). An ordinary multiphoton scanning microscope system was built using a visible CW diode laser and the lateral imaging resolution as high as 161-nm was achieved via the four-photon upconversion process. The demonstrated large saturation excitation power for Nd(3+)-UCNPs would be more practical and facilitate the four-photon imaging in the application. A sample with fine structure was imaged to demonstrate the advantages of visible-to-visible four-photon ultrahigh resolution microscopic imaging with 730-nm diode laser excited nanocrystals. Combining the uniqueness of UCNPs, the proposed visible-to-visible four-photon imaging would be highly promising and attractive in the field of multiphoton imaging.

  14. Making the Invisible Visible: A Methodological and a Substantive Issue

    Science.gov (United States)

    Dagley, Valerie

    2004-01-01

    This article discusses the issue of "making the invisible visible" from a methodological and a substantive viewpoint. The ideas emerged from a doctoral research study into individual target setting with middle ability students in an English secondary school. The students involved had been identified by assessments as "average"…

  15. Making Practice Visible through Writing for Professional Publication

    Science.gov (United States)

    Roberts, Sherron Killingsworth

    2016-01-01

    Why should educators and service professionals bother writing for professional publication? Experienced editor, Sherron Roberts says writing for professional publication allows educators to share their work and make their practice visible. Any educator is quite capable of writing for a professional publication. This article is intended to show…

  16. Visibility of Diversity within Association of Research Libraries Websites

    Science.gov (United States)

    Mestre, Lori S.

    2011-01-01

    Libraries in the United States have worked towards developing more inclusive environments and programs. This inclusiveness should also extend to the online library presence. This article provides results of a web page scan of all Association of Research Libraries (ARL) in the United States to document the visibility of diversity on their pages. A…

  17. Publish or perish: remaining academically relevant and visible in the ...

    African Journals Online (AJOL)

    To improve the visibility of scholars' works and make them relevant on the academic scene, electronic publishing will be advisable. This provides the potential to readers to search and locate the ar ticles at minimum time within one journal or across multiple journals. This includes publishing articles in journals that are ...

  18. Rapid Prototyping of Standard Compliant Visible Light Communications System

    OpenAIRE

    Gavrincea, Ciprian; Baranda, Jorge; Henarejos, Pol

    2014-01-01

    This article describes the implementation of a prototype visible light communications system based on the IEEE 802.15.7 standard using low-cost commercial off-the-shelf analog devices. The aim of this article is to show that this standard provides a framework that could promote the introduction of applications into the market. Thus, these specifications could be further developed, reducing the gap between the industry and research communities. The implemented prototype makes use of software d...

  19. Visible light communications modulation and signal processing

    CERN Document Server

    Wang, Zhaocheng; Huang, Wei; Xu, Zhengyuan

    2018-01-01

    This informative new book on state-of-the-art visible light communication (VLC) provides, for the first time, a systematical and advanced treatment of modulation and signal processing for VLC. Visible Light Communications: Modulation and Signal Processing offers a practical guide to designing VLC, linking academic research with commercial applications. In recent years, VLC has attracted attention from academia and industry since it has many advantages over the traditional radio frequency, including wide unregulated bandwidth, high security, and low cost. It is a promising complementary technique in 5G and beyond wireless communications, especially in indoor applications. However, lighting constraints have not been fully considered in the open literature when considering VLC system design, and its importance has been underestimated. That’s why this book—written by a team of experts with both academic research experience and industrial development experience in the field—is so welcome. To help readers u...

  20. Advances and prospects in visible light communications

    International Nuclear Information System (INIS)

    Chen Hongda; Wu Chunhui; Li Honglei; Chen Xiongbin; Gao Zongyu; Cui Shigang; Wang Qin

    2016-01-01

    Visible light communication (VLC) is an emerging technology in optical wireless communication (OWC) that has attracted worldwide research in recent years. VLC can combine communication and illumination together, which could be applied in many application scenarios such as visible light communication local area networks (VLANs), indoor localization, and intelligent lighting. In recent years, pioneering and significant work have been made in the field of VLC. In this paper, an overview of the recent progress in VLC is presented. We also demonstrate our recent experiment results including bidirectional 100 Mbit/s VLAN or Li-Fi system based on OOK modulation without blue filter. The VLC systems that we proposed are good solutions for high-speed VLC application systems with low-cost and low-complexity. VLC technology shows a bright future due to its inherent advantages, shortage of RF spectra and ever increasing popularity of white LEDs. (review)

  1. Analysis of major antioxidants from extracts of Myrmecodia pendans by UV/visible spectrophotometer, liquid chromatography/tandem mass spectrometry, and high-performance liquid chromatography/UV techniques.

    Science.gov (United States)

    Engida, Adam Mekonnen; Faika, Sitti; Nguyen-Thi, Bich Thuyen; Ju, Yi-Hsu

    2015-06-01

    In the present work, heat reflux extraction with ethanol/water (80:20; v/v) as the solvent was used to extract antioxidants from Myrmecodia pendans. The crude extract (CE) was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF) and aqueous fraction were collected. Antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power of the CE, EAF, and aqueous fraction were evaluated. EAF showed comparable antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power to those of the CE. UV/visible, liquid chromatography/electrospray ionization/tandem mass spectrometry, and high-performance liquid chromatography were employed for identifying the major antioxidant compounds in the EAF. Three major phenolic compounds (rosmarinic acid, procyanidin B1, and polymer of procyanidin B1) were identified. The first two compounds were confirmed and quantified by high-performance liquid chromatography using authentic standards, but confirmation of the third compound was hampered by a lack of commercial standard. Concentrations of rosmarinic acid and procyanidin B1 in the EAF were found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively. All these three compounds are reported for the first time in sarang semut. Copyright © 2014. Published by Elsevier B.V.

  2. Analysis of major antioxidants from extracts of Myrmecodia pendans by UV/visible spectrophotometer, liquid chromatography/tandem mass spectrometry, and high-performance liquid chromatography/UV techniques

    Directory of Open Access Journals (Sweden)

    Adam Mekonnen Engida

    2015-06-01

    Full Text Available In the present work, heat reflux extraction with ethanol/water (80:20; v/v as the solvent was used to extract antioxidants from Myrmecodia pendans. The crude extract (CE was fractionated using hexane and ethyl acetate. Ethyl acetate fraction (EAF and aqueous fraction were collected. Antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power of the CE, EAF, and aqueous fraction were evaluated. EAF showed comparable antioxidant activity against 1,1-diphenyl-2-picrylhydrazyl-radical radical and ferric reducing power to those of the CE. UV/visible, liquid chromatography/electrospray ionization/tandem mass spectrometry, and high-performance liquid chromatography were employed for identifying the major antioxidant compounds in the EAF. Three major phenolic compounds (rosmarinic acid, procyanidin B1, and polymer of procyanidin B1 were identified. The first two compounds were confirmed and quantified by high-performance liquid chromatography using authentic standards, but confirmation of the third compound was hampered by a lack of commercial standard. Concentrations of rosmarinic acid and procyanidin B1 in the EAF were found to be 20.688 ± 1.573 mg/g dry sample and 3.236 ± 0.280 mg/g dry sample, respectively. All these three compounds are reported for the first time in sarang semut.

  3. Tweeting News Articles

    Directory of Open Access Journals (Sweden)

    Marco Toledo Bastos

    2013-09-01

    Full Text Available In this article we investigate the impact of social media readership to the editorial profile of newspapers. We analyze tweets containing links to news articles from eight of the largest national newspapers in the United States, United Kingdom, Spain, Brazil, and Germany. The data collection follows the first two weeks of October 2012 and includes 2,842,699 tweets with links to news articles. Twitter-shortened links were resolved using a three-pass routine and assigned to 1 of the 21 newspaper sections. We found the concentration of links to news articles posted by top users to be lower than reported in the literature and the strategy of relaying headlines on Twitter via automatic news aggregators (feeds to be inefficient. The results of this investigation show which sections of a newspaper are the most and least read by readers in different parts of the world, with German readers placing greater emphasis on Politics and Economy; Brazilians on Sports and Arts; Spaniards on Local and National news; Britons and Americans on Opinion and World news. We also found that German and Spanish readers are more likely to read multiple national newspapers, while British readers more often resort to foreign sources of news. The results confirm that feedback to news items from a large user base is pivotal for the replication of content and that newspapers and news items can be clustered according to the editorial profile and principles of newsworthiness inherited from legacy media. The results of this investigation shed light onto the networked architecture of journalism that increasingly depends on readership agency.

  4. High Density Metamaterials for Visible Light

    Science.gov (United States)

    2016-11-28

    longitudinal plasmons with magnetic characteristics , whose field distribution is qualitatively similar to that in m0 mode for isolated SRR structure. On...gold first and then extend the techniques to other metals for better characteristics . Bio-chemical sensors will be developed based on different split...and Discussion (1) Observation of the kinetic inductance limitation for the fundamental magnetic resonance in ultrasmall gold v-shape split ring

  5. Dense ceramic articles

    International Nuclear Information System (INIS)

    Cockbain, A.G.

    1976-01-01

    A method is described for the manufacture of articles of substantially pure dense ceramic materials, for use in severe environments. Si N is very suitable for use in such environments, but suffers from the disadvantage that it is not amenable to sintering. Some disadvantages of the methods normally used for making articles of Si N are mentioned. The method described comprises mixing a powder of the substantially pure ceramic material with an additive that promotes densification, and which is capable of nuclear transmutation into a gas when exposed to radiation, and hot pressing the mixture to form a billet. The billet is then irradiated to convert the additive into a gas which is held captive in the billet, and it is then subjected to a hot forging operation, during which the captive gas escapes and an article of substantially pure dense ceramic material is forged. The method is intended primarily for use for Si N, but may be applied to other ceramic materials. The additive may be Li or Be or their compounds, to the extent of at least 5 ppm and not more than 5% by weight. Irradiation is effected by proton or neutron bombardment. (UK)

  6. [The (in)visibility of psychological family violence in childhood and adolescence].

    Science.gov (United States)

    Abranches, Cecy Dunshee de; Assis, Simone Gonçalves de

    2011-05-01

    Psychological family violence in childhood and adolescence is still poorly studied, due to difficulties in its definition and detection. This article aims to examine how psychological family violence reported by children and adolescents has been addressed in academic studies, using a literature review (LILACS, MEDLINE, SciELO, PubMed, CAPES Portal, PsycINFO, and SCOPUS databases). Among 51 epidemiological studies, 16 articles met the review's objectives; some of the articles reported a high prevalence of such violence. The study showed that the issue has been studied more in the international literature than in Brazil, which has significantly increased its visibility in the last decade but still faces difficulties involving definition, conceptualization, and operationalization. Eliminating the invisibility of psychological violence in the family could help promote prevention of such violence and protection of children and adolescents.

  7. High performance structural laminate composite material for use to 1000.degree. F. and above, apparatus for and method of manufacturing same, and articles made with same

    Science.gov (United States)

    Seal, Ellis C. (Inventor); Biggs, Jr., Robert William (Inventor); Bodepudi, Venu Prasad (Inventor); Cranston, John A. (Inventor)

    2003-01-01

    A novel materials technology has been developed and demonstrated for providing a high modulus composite material for use to 1000.degree. F. and above. This material can be produced at 5-20% of the cost of refractory materials, and has higher structural properties. This technology successfully resolves the problem of thermal shock or ply lift, which limits traditional high temperature laminates (such as graphite/polyimide and graphite/phenolic) to temperatures of 550-650.degree. F. in thicker (0.25 and above) laminates. The technology disclosed herein is an enabling technology for the nose for the External Tank (ET) of the Space Shuttle, and has been shown to be capable of withstanding the severe environments encountered by the nose cone through wind tunnel testing, high temperature subcomponent testing, and full scale structural, dynamic, acoustic, and damage tolerance testing.

  8. Young Science Journalism: Writing Popular Scientific Articles May Contribute to an Increase of High-School Students' Interest in the Natural Sciences

    Science.gov (United States)

    Simon, Uwe K.; Steindl, Hanna; Larcher, Nicole; Kulac, Helga; Hotter, Annelies

    2016-01-01

    Far too few high-school students choose subjects from the natural sciences (NaSc) for their majors in many countries. Even fewer study biology, chemistry or physics at university. Those, that do, often lack training to present and discuss scientific results and ideas in texts. To meet these challenges the center for didactics of biology of Graz…

  9. Understanding and Approaching Muslim Visibilities

    DEFF Research Database (Denmark)

    Schmidt, Garbi

    2011-01-01

    Within Western nation-states such as Denmark, Islamic identities are often seen as inherently and divergently visible, an aspect that some argue is detrimental to the secular nation-state. From a research perspective, one way to nuance this position is by focusing on groups of 'invisible' Muslims...

  10. Early Learning Theories Made Visible

    Science.gov (United States)

    Beloglovsky, Miriam; Daly, Lisa

    2015-01-01

    Go beyond reading about early learning theories and see what they look like in action in modern programs and teacher practices. With classroom vignettes and colorful photographs, this book makes the works of Jean Piaget, Erik Erikson, Lev Vygotsky, Abraham Maslow, John Dewey, Howard Gardner, and Louise Derman-Sparks visible, accessible, and easier…

  11. Non-Euclidean visibility problems

    Indian Academy of Sciences (India)

    FERNANDO CHAMIZO. Departamento de Matemáticas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. MS received 14 November 2005. Abstract. We consider the analog of visibility problems in hyperbolic plane (repre- sented by Poincaré half-plane model H), replacing the standard lattice Z ...

  12. Are naked singularities really visible

    Energy Technology Data Exchange (ETDEWEB)

    Calvani, M [Padua Univ. (Italy). Ist. di Astronomia; De Felice, F [Alberta Univ., Edmonton (Canada); Nobili, L [Padua Univ. (Italy). Ist. di Fisica

    1978-12-09

    The question whether a Kerr naked singularity is actually visible from infinity is investigated; it is shown that in fact any signal which could be emitted from the singularity is infinitely red-shifted. This implies that naked singularities would be indistinguishable from a black hole.

  13. Visible Machine Learning for Biomedicine.

    Science.gov (United States)

    Yu, Michael K; Ma, Jianzhu; Fisher, Jasmin; Kreisberg, Jason F; Raphael, Benjamin J; Ideker, Trey

    2018-06-14

    A major ambition of artificial intelligence lies in translating patient data to successful therapies. Machine learning models face particular challenges in biomedicine, however, including handling of extreme data heterogeneity and lack of mechanistic insight into predictions. Here, we argue for "visible" approaches that guide model structure with experimental biology. Copyright © 2018. Published by Elsevier Inc.

  14. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... ecological process purity. ... stabilizer; 3 - tension transformer; 4 - digit camera bioreactor; 5 - resistor block; 6 - high- ... high ecology of conducting process. .... by transport of electrons on a chain of oxidation-reduction reaction.

  15. Research Article Special Issue

    African Journals Online (AJOL)

    2017-08-08

    Aug 8, 2017 ... sucrose and lactose media exhibited that the cellulose pro rxylinus DSM 46604 resembled good ... industry, high precision acoustic speakers manufacturing, high quality paper and food industry. [6-7]. Different saccharides for ...

  16. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-03-22

    Mar 22, 2018 ... high accuracy when dealing with human life [1]. A variety of ... It has proven to provide high quality medical images and has been widely ..... International Journal of Interactive Multimedia and Artificial Intelligence, vol. 1, no. 7,.

  17. Website visibility the theory and practice of improving rankings

    CERN Document Server

    Weideman, Melius

    2009-01-01

    The quest to achieve high website rankings in search engine results is a prominent subject for both academics and website owners/coders. Website Visibility marries academic research results to the world of the information practitioner and contains a focused look at the elements which contribute to website visibility, providing support for the application of each element with relevant research. A series of real-world case studies with tested examples of research on website visibility elements and their effect on rankings are reviewed.Written by a well-respected academic and practitioner in the

  18. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-10

    Nov 10, 2017 ... digital controller, these power switches perform power conversion by synthesizing the multiple DC voltage sources into a high voltage stepped output waveform. Multilevel inverters are mostly employed in medium-to-high-voltage range in utility and drive applications namely high-power motor drive, power ...

  19. Research Article Special Issue

    African Journals Online (AJOL)

    2016-07-16

    Jul 16, 2016 ... environment, welfare, or public health. ... annually, primarily due to cardiac effects (James, Bereitschaft, 2011). ... design have been taken into consideration and the purpose is to develop the demand for ... advantages including high capacity, high speed, safety, high reliability, lower costs, and comfort,.

  20. Photodetector Characteristics in Visible Light Communication

    KAUST Repository

    Ho, Kang-Ting

    2016-04-01

    Typically, in the semiconductor industry pn heterojunctions have been used as either light-emitting diodes (LED) or photodiodes by applying forward current bias or reverse voltage bias, respectively. However, since both devices use the same structure, the light emitting and detecting properties could be combine in one single device, namely LED-based photodetector. Therefore, by integrating LED-based photodetectors as either transmitter or receiver, optical wireless communication could be easily implemented for bidirectional visible light communication networks at low-cost. Therefore, this dissertation focus on the investigation of the photodetection characteristics of InGaN LED-based photodetectors for visible light communication in the blue region. In this regard, we obtain external quantum efficiency of 10 % and photoresponse rise time of 71 μs at 405-nm illumination, revealing high-performance photodetection characteristics. Furthermore, we use orthogonal frequency division multiplexing quadrature amplitude modulation codification scheme to enlarge the operational bandwidth. Consequently, the transmission rate of the communication is efficiently enhanced up to 420 Mbit/s in visible light communication.

  1. Visible-to-near IR quantum dot-based hypermulticolor high-content screening of herbal medicines for the efficacy monitoring of hair growth promotion and hair loss inhibition.

    Science.gov (United States)

    Kim, Min Jung; Lim, Chaeyun; Lee, Jun Young; Im, Kyung Ran; Yoon, Kyung-Sup; Song, Joon Myong

    2013-04-01

    There is a growing interest in alopecia prevention strategies, as the number of alopecia patients is increasing. We examine the efficacy of herbal medicine for hair growth promotion/hair loss inhibition in two cell lines via Western blot and high-content screening (HCS). Nine herbal extracts were obtained from three different herbal medicine mixtures using 3 different extraction methods. Five target proteins-IGF-1 (insulin-like growth factor-1), TGF-β2 (transforming growth factor-β2), VEGF (vascular endothelial growth factor), DKK-1 (Dickkopf-1), and Wnt5α-were observed for the assessment of hair growth promotion/hair loss inhibition efficacy. The efficacies of nine extracts were compared with minoxidil as control. Efficacy was defined as a rise in the expression levels of IGF-1, VEGF, and Wnt5α but a decrease in DKK-1 and TGF-β2. Intracellular concurrent imaging of these proteins was successfully achieved using HCS, employing visible-to-near infrared probing based on quantum-antibody conjugates and hypermulticolor imaging.

  2. One-step synthesis of highly active Ti-containing Cr-modified MCM-48 mesoporous material and the photocatalytic performance for decomposition of H{sub 2}S under visible light

    Energy Technology Data Exchange (ETDEWEB)

    Wang Zhen; Ci Xinbo; Dai Hongjun; Yin Lu [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China); Shi Huixiang, E-mail: lanyueheyu@163.com [Department of Environmental Engineering, Zhejiang University, Hangzhou 310027 (China)

    2012-08-01

    A highly photoactive Ti-containing Cr-modified MCM-48 photocatalyst (Si/Ti = 3.4, Si/Cr = 50) was prepared by a facile one-step method at room temperature. A combination of various physicochemical techniques such as X-ray diffraction (XRD), N{sub 2} physisorption, diffuse reflectance UV-vis spectra (DRS) and X-ray photoelectron spectra (XPS) were used to characterize the properties of the synthetic catalysts. The characterization and experimental results indicated that tetrahedral Ti oxide moieties as dominant Ti oxide were loaded into the mesoporous structure and there was a synergistic interaction between the Ti species anchored on the walls and the Cr ions presented in the MCM-48 framework, which was considered to be directly correlated to the photoactivity. The Ti-Cr-MCM-48 sample can remove H{sub 2}S with the efficiency of 92% under visible light, being the Cr{sup 6+} species primarily responsible for this photoactivity. A deactivation was observed as a consequence of sulfate accumulation on the surface of the catalyst and reduction of Cr{sup 6+}.

  3. Towards a semiquantitative non invasive characterisation of Tyrian purple dye composition: Convergence of UV-Visible reflectance spectroscopy and fast-high temperature-high performance liquid chromatography with photodiode array detection.

    Science.gov (United States)

    Clementi, Catia; Nowik, Witold; Romani, Aldo; Cardon, Dominique; Trojanowicz, Marek; Davantès, Athénaïs; Chaminade, Pierre

    2016-07-05

    In this paper, partial least square (PLS) regression is innovatively applied for a semi-quantitative non invasive study of the most precious dye of Antiquity: Tyrian purple. This original approach for the study of organic dyes in the cultural heritage field, is based on the correlation of spectrophotometric (UV-Visible) and chromatographic (Fast-HT-HPLC-PDA) data from an extensive set of textiles prepared with different snail species according to historical recipes. A cross-validated PLS model, based on the quantity of 6,6'-dibromoindigotin, displays an excellent correlation factor (R(2)Y = 0.987) between values determined by chromatography and those predicted from reflectance spectra. This indicates that the spectral features of Tyrian purple on textile fibre is strictly related to the amount of this indigoid component whose content may be non invasively predicted from reflectance spectrum. The studied correlation also highlights that, independently of the dyeing method and nature of the textile fibre used, the relative content of 6,6'-dibromindigotin may be used as a parameter to distinguish samples prepared with Hexaplex trunculus L. snails from those prepared with further mollusc species. To validate this model, archaeological textile fragments dating from the Roman period were successfully examined. The results achieved open an absolutely new way in Tyrian purple analysis in cultural heritage by non invasive spectroscopic techniques attesting their convergence with HPLC and giving them a semi-quantitative value. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Prompting Students to Contemplate Effective Communication with a Visible Speech Chart from the 1870s

    Science.gov (United States)

    Potter, Lee Ann

    2014-01-01

    In this article, director of Educational Outreach at the Library of Congress Lee Ann Potter describes a classroom activity that focuses on an 1876 single-page circular published in Salem, Massachusetts about Alexander Melville Bell's Visible Speech. A. M. Bell's son, Alexander Graham Bell described "Visible Speech" as "a…

  5. An economic analysis of high-dose imatinib, dasatinib, and nilotinib for imatinib-resistant chronic phase chronic myeloid leukemia in China: A CHEERS-compliant article.

    Science.gov (United States)

    Wu, Bin; Liu, Maobai; Li, Te; Lin, Houwen; Zhong, Hua

    2017-07-01

    The aim of the study was to test the cost-effectiveness of dasatinib compared to high-dose imatinib and nilotinib in Chinese patients who were diagnosed with imatinib-resistant chronic myeloid leukemia in the chronic phase (CML-CP). A Markov model combined with clinical effectiveness, utility, and cost data was used. The sensitivity analyses were conducted to determine the robustness of the model outcomes. The impact of patient assistance programs (PAPs) was assessed. Treatment with dasatinib is expected to produce 3.65, 0.59, and 0.15 more quality-adjusted life years (QALYs) in comparison with high-dose imatinib (600 and 800 mg) and nilotinib, respectively. When a PAP was available, dasatinib yielded an incremental cost of $16,417 per QALY compared to imatinib (600 mg) and was cost-saving compared to imatinib (800 mg) and nilotinib. When PAP is available in the Chinese setting, dasatinib is likely to be a cost-effective strategy for patients with CML-CP standard-dose imatinib resistance. The results should be carefully explained due to the assumptions and limitations used in the study.

  6. Research Article. The Influence of Some Parameters on Chiral Separation of Ibuprofen by High-Performance Liquid Chromatography and Capillary Electrophoresis

    Directory of Open Access Journals (Sweden)

    Balint Alina

    2017-03-01

    Full Text Available Objective: The aim of the study was to compare the influence of mobile phase composition and temperature on chiral separation of racemic ibuprofen by capillary electrophoresis and high performance liquid chromatography with UV detection. Materials and methods: Racemic ibuprofen was analysed on a chiral OVM column with an HPLC system 1100 Agilent Technologies, under isocratic elution, by using potassium dihydrogen phosphate 20 mM and ethanol in mobile phase. The flow rate was set at 1 mL/min, UV detector at 220 nm and different column temperatures were tested. For electrophoresis separation an Agilent CE G1600AX Capillary Electrophoresis System system, with UV detection, was used. The electrophoresis analysis was performed at different pH values and temperatures, with phosphate buffer 25 mM and methyl-β-cyclodextrin as chiral selector. Results: The chromatograhic analysis reveals a high influence of mobile phase pH on ibuprofen enantiomers separation. An elution with a mixture of potassium dihydrogen phosphate 20 mM pH=3 and ethanol, at 25°C, allowed enantiomers separation with good resolution in less than 8 min. Conclusions: The proposed HPLC method proved suitable for the separation of ibuprofen enantiomers with a good resolution, but the capillary electrophoresis tested parameters did not allow chiral discrimination.

  7. Predictors of High Motivation Score for Performing Research Initiation Fellowship, Master 1, Research Master 2, and PhD Curricula During Medical Studies: A Strobe-Compliant Article.

    Science.gov (United States)

    Feigerlova, Eva; Oussalah, Abderrahim; Fournier, Jean-Paul; Antonelli, Arnaud; Hadjadj, Samy; Marechaud, Richard; Guéant, Jean-Louis; Roblot, Pascal; Braun, Marc

    2016-02-01

    Translational research plays a crucial role in bridging the gap between fundamental and clinical research. The importance of integrating research training into medical education has been emphasized. Predictive factors that help to identify the most motivated medical students to perform academic research are unknown. In a cross-sectional study on a representative sample of 315 medical students, residents and attending physicians, using a comprehensive structured questionnaire we assessed motivations and obstacles to perform academic research curricula (ie, research initiation fellowship, Master 1, Research Master 2, and PhD). Independent predictive factors associated with high "motivation score" (top quartile on motivation score ranging from 0 to 10) to enroll in academic research curricula were derived using multivariate logistic regression analysis. Independent predictors of high motivation score for performing Master 1 curriculum were: "considering that the integration of translational research in medical curriculum is essential" (OR, 3.79; 95% CI, 1.49-9.59; P = 0.005) and "knowledge of at least 2 research units within the university" (OR, 3.60; 95% CI, 2.01-6.47; P motivation score for performing Research Master 2 curriculum were: "attending physician" (OR, 4.60; 95% CI, 1.86-11.37; P = 0.001); "considering that the integration of translational research in medical curriculum is essential" (OR, 4.12; 95% CI, 1.51-11.23; P = 0.006); "knowledge of at least 2 research units within the university" (OR, 3.51; 95% CI, 1.91-6.46; P = 0.0001); and "male gender" (OR, 1.82; 95% CI, 1.02-3.25; P = 0.04). Independent predictors of high motivation score for performing PhD curriculum were: "considering that the integration of translational research in medical curriculum is essential" (OR, 5.94; 95% CI, 2.33-15.19; P = 0.0002) and "knowledge of at least 2 research units within the university" (OR, 2.63; 95% CI, 1.46-4.77; P = 0.001). This is the

  8. Radiation cured silicone rubber articles

    International Nuclear Information System (INIS)

    DuPont, J.G.; Goodwin, P.A.

    1984-01-01

    A process for making radiation cured silicone rubber articles is disclosed wherein a hydroxyl-terminated polysilaxane having a molecular weight from about 50,000 to about 2,000,000, optionally modified by mixing with up to 85% of an end-stopped silicone rubber, is mixed with from about 10 to about 70 parts per hundred of rubber of a finely divided silica filler with a particle size in the reinforcing range and other inert fillers as determined by desired final properties; the composition so prepared is formed into the desired shape at room temperature; the article so formed is precured to improve the mechanical properties of the material with which it is made by exposure to ammonia gas, ammonium hydroxide, or to the vapors or solutions of a volatile amine at room temperature; and the precured article is irradiated with high energy electrons or gamma radiation to effect a permanent cure of the material from which the article is formed

  9. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-05-01

    May 1, 2018 ... They can be found in cross over network used in a three-way high fidelity loud speaker, portable ECG ..... •Switching speed is very high. Fig.17. Circuit diagram of .... RESULTS OF SOFTWARE SIMULATION. The working of the ...

  10. Research Article Special Issue

    African Journals Online (AJOL)

    2017-09-10

    Sep 10, 2017 ... ABSTRACT. This paper presenting a new electrocard transform technique. The system involves t with ECG thresholds with several thresho second stage filtration using the high/low capable to counter the unpredictability of movement. Wavelets may reduce the motio both high and low frequency signals an.

  11. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2018-04-16

    Apr 16, 2018 ... The most important factor in the production of high-quality nickel ... ensures the high quality of the produced galvanic coatings while ... a comparative analysis of the effectiveness of the application of .... temperatures - 68-75 oC. ... Properties of solutions of nickel-containing electrolytes for workers ik (A/dm2).

  12. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-24

    Nov 24, 2017 ... Department of Architecture & Civil Engineering, RUDN University, ... In our study we used concrete modifier MB10-01, an admixture on an organic-mineral basis ... High-strength concrete is a durable material, and it has superior ..... High Strength Concrete Elements in Simulated Aggressive Environments.

  13. Ultraviolet, Visible, and Fluorescence Spectroscopy

    Science.gov (United States)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  14. Research Article Special Issue

    African Journals Online (AJOL)

    2017-09-10

    Sep 10, 2017 ... tunnel testing to determine the aerodynamic behavior during flight ha .... behavior nflation pressures and under different flow conditions [29 tenna and .... material that have high gas retention capability such as PE or PU film.

  15. Original Research Article

    African Journals Online (AJOL)

    Erah

    2009-06-05

    Jun 5, 2009 ... receptor activity and that the possibility of. LDL consumption .... a risk factor for coronary events in older men and women. .... treatment of high blood cholesterol in adults (Adult. Treatment ... Can Fam Physic 2001; 47: 303-309.

  16. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-10-17

    Oct 17, 2017 ... Data visualization is a term used for visual images that help users to understand complex data [1] through ..... The center is located at high educational institution MARA University of .... Mining geo-location in social networks.

  17. ·: ORIGINAL ARTICLES

    African Journals Online (AJOL)

    this figure is low compared with figures from other studies in .... a long summer period, high temperatures and wind are major factors contributing to the production of ..... Eragrostis grasses. Values shown are mean cpm of triplicate wells as.

  18. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... onHelicobacter Pylori (HP). ... turmeric and cinnamon by agar diffusion on helicobacter pylori have high ... flora of the gastrointestinal tract, mouth and vagina and people often receive ... was produced through water distillation.

  19. Research Article Special Issue

    African Journals Online (AJOL)

    pc

    2017-11-10

    Nov 10, 2017 ... telecommunications industry has become a rapidly growing market. ... that if firms are fully aware of which segment of the customers poses high risk of churn, ... where y = dependent variables or predicted values, α = constant ...

  20. Research Article Special Issue

    African Journals Online (AJOL)

    2016-05-15

    May 15, 2016 ... For this purpose, 400 female high school students of Kerman .... physical, psychological and social aspects of school and in fact, shows a ..... Business Media. ... accountability tool for elementary school counselors to measure ...